Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

470 files changed, 122834 insertions, 0 deletions

diff --git a/toolkit/components/places/BookmarkHTMLUtils.sys.mjs b/toolkit/components/places/BookmarkHTMLUtils.sys.mjs
new file mode 100644
index 0000000000..559d8b9a8e
--- /dev/null
+++ b/toolkit/components/places/BookmarkHTMLUtils.sys.mjs
@@ -0,0 +1,1167 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file works on the old-style "bookmarks.html" file.  It includes
+ * functions to import and export existing bookmarks to this file format.
+ *
+ * Format
+ * ------
+ *
+ * Primary heading := h1
+ *   Old version used this to set attributes on the bookmarks RDF root, such
+ *   as the last modified date. We only use H1 to check for the attribute
+ *   PLACES_ROOT, which tells us that this hierarchy root is the places root.
+ *   For backwards compatibility, if we don't find this, we assume that the
+ *   hierarchy is rooted at the bookmarks menu.
+ * Heading := any heading other than h1
+ *   Old version used this to set attributes on the current container. We only
+ *   care about the content of the heading container, which contains the title
+ *   of the bookmark container.
+ * Bookmark := a
+ *   HREF is the destination of the bookmark
+ *   FEEDURL is the URI of the RSS feed. This is deprecated and no more
+ *   supported, but some old files may still contain it.
+ *   LAST_CHARSET is stored as an annotation so that the next time we go to
+ *     that page we remember the user's preference.
+ *   ICON will be stored in the favicon service
+ *   ICON_URI is new for places bookmarks.html, it refers to the original
+ *     URI of the favicon so we don't have to make up favicon URLs.
+ *   Text of the <a> container is the name of the bookmark
+ *   Ignored: LAST_VISIT, ID (writing out non-RDF IDs can confuse Firefox 2)
+ * Bookmark comment := dd
+ *   This affects the previosly added bookmark
+ * Separator := hr
+ *   Insert a separator into the current container
+ * The folder hierarchy is defined by <dl>/<ul>/<menu> (the old importing code
+ *     handles all these cases, when we write, use <dl>).
+ *
+ * Overall design
+ * --------------
+ *
+ * We need to emulate a recursive parser. A "Bookmark import frame" is created
+ * corresponding to each folder we encounter. These are arranged in a stack,
+ * and contain all the state we need to keep track of.
+ *
+ * A frame is created when we find a heading, which defines a new container.
+ * The frame also keeps track of the nesting of <DL>s, (in well-formed
+ * bookmarks files, these will have a 1-1 correspondence with frames, but we
+ * try to be a little more flexible here). When the nesting count decreases
+ * to 0, then we know a frame is complete and to pop back to the previous
+ * frame.
+ *
+ * Note that a lot of things happen when tags are CLOSED because we need to
+ * get the text from the content of the tag. For example, link and heading tags
+ * both require the content (= title) before actually creating it.
+ */
+
+import { NetUtil } from "resource://gre/modules/NetUtil.sys.mjs";
+
+import { FileUtils } from "resource://gre/modules/FileUtils.sys.mjs";
+import { PlacesUtils } from "resource://gre/modules/PlacesUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesBackups: "resource://gre/modules/PlacesBackups.sys.mjs",
+});
+
+const Container_Normal = 0;
+const Container_Toolbar = 1;
+const Container_Menu = 2;
+const Container_Unfiled = 3;
+const Container_Places = 4;
+
+const MICROSEC_PER_SEC = 1000000;
+
+const EXPORT_INDENT = "    "; // four spaces
+
+function base64EncodeString(aString) {
+  let stream = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(
+    Ci.nsIStringInputStream
+  );
+  stream.setData(aString, aString.length);
+  let encoder = Cc["@mozilla.org/scriptablebase64encoder;1"].createInstance(
+    Ci.nsIScriptableBase64Encoder
+  );
+  return encoder.encodeToString(stream, aString.length);
+}
+
+/**
+ * Provides HTML escaping for use in HTML attributes and body of the bookmarks
+ * file, compatible with the old bookmarks system.
+ */
+function escapeHtmlEntities(aText) {
+  return (aText || "")
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;")
+    .replace(/'/g, "&#39;");
+}
+
+/**
+ * Provides URL escaping for use in HTML attributes of the bookmarks file,
+ * compatible with the old bookmarks system.
+ */
+function escapeUrl(aText) {
+  return (aText || "").replace(/"/g, "%22");
+}
+
+function notifyObservers(aTopic, aInitialImport) {
+  Services.obs.notifyObservers(
+    null,
+    aTopic,
+    aInitialImport ? "html-initial" : "html"
+  );
+}
+
+export var BookmarkHTMLUtils = Object.freeze({
+  /**
+   * Loads the current bookmarks hierarchy from a "bookmarks.html" file.
+   *
+   * @param aSpec
+   *        String containing the "file:" URI for the existing "bookmarks.html"
+   *        file to be loaded.
+   * @param [options.replace]
+   *        Whether we should erase existing bookmarks before loading.
+   *        Defaults to `false`.
+   * @param [options.source]
+   *        The bookmark change source, used to determine the sync status for
+   *        imported bookmarks. Defaults to `RESTORE` if `replace = true`, or
+   *        `IMPORT` otherwise.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                           folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromURL(
+    aSpec,
+    {
+      replace: aInitialImport = false,
+      source: aSource = aInitialImport
+        ? PlacesUtils.bookmarks.SOURCES.RESTORE
+        : PlacesUtils.bookmarks.SOURCES.IMPORT,
+    } = {}
+  ) {
+    let bookmarkCount;
+    notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_BEGIN, aInitialImport);
+    try {
+      let importer = new BookmarkImporter(aInitialImport, aSource);
+      bookmarkCount = await importer.importFromURL(aSpec);
+
+      notifyObservers(
+        PlacesUtils.TOPIC_BOOKMARKS_RESTORE_SUCCESS,
+        aInitialImport
+      );
+    } catch (ex) {
+      console.error(`Failed to import bookmarks from ${aSpec}:`, ex);
+      notifyObservers(
+        PlacesUtils.TOPIC_BOOKMARKS_RESTORE_FAILED,
+        aInitialImport
+      );
+      throw ex;
+    }
+    return bookmarkCount;
+  },
+
+  /**
+   * Loads the current bookmarks hierarchy from a "bookmarks.html" file.
+   *
+   * @param aFilePath
+   *        OS.File path string of the "bookmarks.html" file to be loaded.
+   * @param [options.replace]
+   *        Whether we should erase existing bookmarks before loading.
+   *        Defaults to `false`.
+   * @param [options.source]
+   *        The bookmark change source, used to determine the sync status for
+   *        imported bookmarks. Defaults to `RESTORE` if `replace = true`, or
+   *        `IMPORT` otherwise.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                            folders and separators
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromFile(
+    aFilePath,
+    {
+      replace: aInitialImport = false,
+      source: aSource = aInitialImport
+        ? PlacesUtils.bookmarks.SOURCES.RESTORE
+        : PlacesUtils.bookmarks.SOURCES.IMPORT,
+    } = {}
+  ) {
+    let bookmarkCount;
+    notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_BEGIN, aInitialImport);
+    try {
+      if (!(await IOUtils.exists(aFilePath))) {
+        throw new Error(
+          "Cannot import from nonexisting html file: " + aFilePath
+        );
+      }
+      let importer = new BookmarkImporter(aInitialImport, aSource);
+      bookmarkCount = await importer.importFromURL(
+        PathUtils.toFileURI(aFilePath)
+      );
+
+      notifyObservers(
+        PlacesUtils.TOPIC_BOOKMARKS_RESTORE_SUCCESS,
+        aInitialImport
+      );
+    } catch (ex) {
+      console.error(`Failed to import bookmarks from ${aFilePath}:`, ex);
+      notifyObservers(
+        PlacesUtils.TOPIC_BOOKMARKS_RESTORE_FAILED,
+        aInitialImport
+      );
+      throw ex;
+    }
+    return bookmarkCount;
+  },
+
+  /**
+   * Saves the current bookmarks hierarchy to a "bookmarks.html" file.
+   *
+   * @param aFilePath
+   *        OS.File path string for the "bookmarks.html" file to be created.
+   *
+   * @return {Promise}
+   * @resolves To the exported bookmarks count when the file has been created.
+   * @rejects JavaScript exception.
+   */
+  async exportToFile(aFilePath) {
+    let [bookmarks, count] = await lazy.PlacesBackups.getBookmarksTree();
+    let startTime = Date.now();
+
+    // Report the time taken to convert the tree to HTML.
+    let exporter = new BookmarkExporter(bookmarks);
+    await exporter.exportToFile(aFilePath);
+
+    try {
+      Services.telemetry
+        .getHistogramById("PLACES_EXPORT_TOHTML_MS")
+        .add(Date.now() - startTime);
+    } catch (ex) {
+      console.error("Unable to report telemetry.");
+    }
+
+    return count;
+  },
+
+  get defaultPath() {
+    try {
+      return Services.prefs.getCharPref("browser.bookmarks.file");
+    } catch (ex) {}
+    return PathUtils.join(PathUtils.profileDir, "bookmarks.html");
+  },
+});
+
+function Frame(aFolder) {
+  this.folder = aFolder;
+
+  /**
+   * How many <dl>s have been nested. Each frame/container should start
+   * with a heading, and is then followed by a <dl>, <ul>, or <menu>. When
+   * that list is complete, then it is the end of this container and we need
+   * to pop back up one level for new items. If we never get an open tag for
+   * one of these things, we should assume that the container is empty and
+   * that things we find should be siblings of it. Normally, these <dl>s won't
+   * be nested so this will be 0 or 1.
+   */
+  this.containerNesting = 0;
+
+  /**
+   * when we find a heading tag, it actually affects the title of the NEXT
+   * container in the list. This stores that heading tag and whether it was
+   * special. 'consumeHeading' resets this._
+   */
+  this.lastContainerType = Container_Normal;
+
+  /**
+   * this contains the text from the last begin tag until now. It is reset
+   * at every begin tag. We can check it when we see a </a>, or </h3>
+   * to see what the text content of that node should be.
+   */
+  this.previousText = "";
+
+  /**
+   * true when we hit a <dd>, which contains the description for the preceding
+   * <a> tag. We can't just check for </dd> like we can for </a> or </h3>
+   * because if there is a sub-folder, it is actually a child of the <dd>
+   * because the tag is never explicitly closed. If this is true and we see a
+   * new open tag, that means to commit the description to the previous
+   * bookmark.
+   *
+   * Additional weirdness happens when the previous <dt> tag contains a <h3>:
+   * this means there is a new folder with the given description, and whose
+   * children are contained in the following <dl> list.
+   *
+   * This is handled in openContainer(), which commits previous text if
+   * necessary.
+   */
+  this.inDescription = false;
+
+  /**
+   * contains the URL of the previous bookmark created. This is used so that
+   * when we encounter a <dd>, we know what bookmark to associate the text with.
+   * This is cleared whenever we hit a <h3>, so that we know NOT to save this
+   * with a bookmark, but to keep it until
+   */
+  this.previousLink = null;
+
+  /**
+   * Contains a reference to the last created bookmark or folder object.
+   */
+  this.previousItem = null;
+
+  /**
+   * Contains the date-added and last-modified-date of an imported item.
+   * Used to override the values set by insertBookmark, createFolder, etc.
+   */
+  this.previousDateAdded = null;
+  this.previousLastModifiedDate = null;
+}
+
+function BookmarkImporter(aInitialImport, aSource) {
+  this._isImportDefaults = aInitialImport;
+  this._source = aSource;
+
+  // This root is where we construct the bookmarks tree into, following the format
+  // of the imported file.
+  // If we're doing an initial import, the non-menu roots will be created as
+  // children of this root, so in _getBookmarkTrees we'll split them out.
+  // If we're not doing an initial import, everything gets imported under the
+  // bookmark menu folder, so there won't be any need for _getBookmarkTrees to
+  // do separation.
+  this._bookmarkTree = {
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [],
+  };
+
+  this._frames = [];
+  this._frames.push(new Frame(this._bookmarkTree));
+}
+
+BookmarkImporter.prototype = {
+  _safeTrim: function safeTrim(aStr) {
+    return aStr ? aStr.trim() : aStr;
+  },
+
+  get _curFrame() {
+    return this._frames[this._frames.length - 1];
+  },
+
+  get _previousFrame() {
+    return this._frames[this._frames.length - 2];
+  },
+
+  /**
+   * This is called when there is a new folder found. The folder takes the
+   * name from the previous frame's heading.
+   */
+  _newFrame: function newFrame() {
+    let frame = this._curFrame;
+    let containerTitle = frame.previousText;
+    frame.previousText = "";
+    let containerType = frame.lastContainerType;
+
+    let folder = {
+      children: [],
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    };
+
+    switch (containerType) {
+      case Container_Normal:
+        // This can only be a sub-folder so no need to set a guid here.
+        folder.title = containerTitle;
+        break;
+      case Container_Places:
+        folder.guid = PlacesUtils.bookmarks.rootGuid;
+        break;
+      case Container_Menu:
+        folder.guid = PlacesUtils.bookmarks.menuGuid;
+        break;
+      case Container_Unfiled:
+        folder.guid = PlacesUtils.bookmarks.unfiledGuid;
+        break;
+      case Container_Toolbar:
+        folder.guid = PlacesUtils.bookmarks.toolbarGuid;
+        break;
+      default:
+        // NOT REACHED
+        throw new Error("Unknown bookmark container type!");
+    }
+
+    frame.folder.children.push(folder);
+
+    if (frame.previousDateAdded != null) {
+      folder.dateAdded = frame.previousDateAdded;
+      frame.previousDateAdded = null;
+    }
+
+    if (frame.previousLastModifiedDate != null) {
+      folder.lastModified = frame.previousLastModifiedDate;
+      frame.previousLastModifiedDate = null;
+    }
+
+    if (
+      !folder.hasOwnProperty("dateAdded") &&
+      folder.hasOwnProperty("lastModified")
+    ) {
+      folder.dateAdded = folder.lastModified;
+    }
+
+    frame.previousItem = folder;
+
+    this._frames.push(new Frame(folder));
+  },
+
+  /**
+   * Handles <hr> as a separator.
+   *
+   * @note Separators may have a title in old html files, though Places dropped
+   *       support for them.
+   *       We also don't import ADD_DATE or LAST_MODIFIED for separators because
+   *       pre-Places bookmarks did not support them.
+   */
+  _handleSeparator: function handleSeparator(aElt) {
+    let frame = this._curFrame;
+
+    let separator = {
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    };
+    frame.folder.children.push(separator);
+    frame.previousItem = separator;
+  },
+
+  /**
+   * Called for h2,h3,h4,h5,h6. This just stores the correct information in
+   * the current frame; the actual new frame corresponding to the container
+   * associated with the heading will be created when the tag has been closed
+   * and we know the title (we don't know to create a new folder or to merge
+   * with an existing one until we have the title).
+   */
+  _handleHeadBegin: function handleHeadBegin(aElt) {
+    let frame = this._curFrame;
+
+    // after a heading, a previous bookmark is not applicable (for example, for
+    // the descriptions contained in a <dd>). Neither is any previous head type
+    frame.previousLink = null;
+    frame.lastContainerType = Container_Normal;
+
+    // It is syntactically possible for a heading to appear after another heading
+    // but before the <dl> that encloses that folder's contents.  This should not
+    // happen in practice, as the file will contain "<dl></dl>" sequence for
+    // empty containers.
+    //
+    // Just to be on the safe side, if we encounter
+    //   <h3>FOO</h3>
+    //   <h3>BAR</h3>
+    //   <dl>...content 1...</dl>
+    //   <dl>...content 2...</dl>
+    // we'll pop the stack when we find the h3 for BAR, treating that as an
+    // implicit ending of the FOO container. The output will be FOO and BAR as
+    // siblings. If there's another <dl> following (as in "content 2"), those
+    // items will be treated as further siblings of FOO and BAR
+    // This special frame popping business, of course, only happens when our
+    // frame array has more than one element so we can avoid situations where
+    // we don't have a frame to parse into anymore.
+    if (frame.containerNesting == 0 && this._frames.length > 1) {
+      this._frames.pop();
+    }
+
+    // We have to check for some attributes to see if this is a "special"
+    // folder, which will have different creation rules when the end tag is
+    // processed.
+    if (aElt.hasAttribute("personal_toolbar_folder")) {
+      if (this._isImportDefaults) {
+        frame.lastContainerType = Container_Toolbar;
+      }
+    } else if (aElt.hasAttribute("bookmarks_menu")) {
+      if (this._isImportDefaults) {
+        frame.lastContainerType = Container_Menu;
+      }
+    } else if (aElt.hasAttribute("unfiled_bookmarks_folder")) {
+      if (this._isImportDefaults) {
+        frame.lastContainerType = Container_Unfiled;
+      }
+    } else if (aElt.hasAttribute("places_root")) {
+      if (this._isImportDefaults) {
+        frame.lastContainerType = Container_Places;
+      }
+    } else {
+      let addDate = aElt.getAttribute("add_date");
+      if (addDate) {
+        frame.previousDateAdded =
+          this._convertImportedDateToInternalDate(addDate);
+      }
+      let modDate = aElt.getAttribute("last_modified");
+      if (modDate) {
+        frame.previousLastModifiedDate =
+          this._convertImportedDateToInternalDate(modDate);
+      }
+    }
+    this._curFrame.previousText = "";
+  },
+
+  /*
+   * Handles "<a" tags by creating a new bookmark. The title of the bookmark
+   * will be the text content, which will be stuffed in previousText for us
+   * and which will be saved by handleLinkEnd
+   */
+  _handleLinkBegin: function handleLinkBegin(aElt) {
+    let frame = this._curFrame;
+
+    frame.previousItem = null;
+    frame.previousText = ""; // Will hold link text, clear it.
+
+    // Get the attributes we care about.
+    let href = this._safeTrim(aElt.getAttribute("href"));
+    let icon = this._safeTrim(aElt.getAttribute("icon"));
+    let iconUri = this._safeTrim(aElt.getAttribute("icon_uri"));
+    let lastCharset = this._safeTrim(aElt.getAttribute("last_charset"));
+    let keyword = this._safeTrim(aElt.getAttribute("shortcuturl"));
+    let postData = this._safeTrim(aElt.getAttribute("post_data"));
+    let dateAdded = this._safeTrim(aElt.getAttribute("add_date"));
+    let lastModified = this._safeTrim(aElt.getAttribute("last_modified"));
+    let tags = this._safeTrim(aElt.getAttribute("tags"));
+
+    // Ignore <a> tags that have no href.
+    try {
+      frame.previousLink = Services.io.newURI(href).spec;
+    } catch (e) {
+      frame.previousLink = null;
+      return;
+    }
+
+    let bookmark = {};
+
+    // Only set the url for bookmarks.
+    if (frame.previousLink) {
+      bookmark.url = frame.previousLink;
+    }
+
+    if (dateAdded) {
+      bookmark.dateAdded = this._convertImportedDateToInternalDate(dateAdded);
+    }
+    // Save bookmark's last modified date.
+    if (lastModified) {
+      bookmark.lastModified =
+        this._convertImportedDateToInternalDate(lastModified);
+    }
+
+    if (!dateAdded && lastModified) {
+      bookmark.dateAdded = bookmark.lastModified;
+    }
+
+    if (tags) {
+      bookmark.tags = tags
+        .split(",")
+        .filter(
+          aTag =>
+            !!aTag.length && aTag.length <= PlacesUtils.bookmarks.MAX_TAG_LENGTH
+        );
+
+      // If we end up with none, then delete the property completely.
+      if (!bookmark.tags.length) {
+        delete bookmark.tags;
+      }
+    }
+
+    if (lastCharset) {
+      bookmark.charset = lastCharset;
+    }
+
+    if (keyword) {
+      bookmark.keyword = keyword;
+    }
+
+    if (postData) {
+      bookmark.postData = postData;
+    }
+
+    if (icon) {
+      bookmark.icon = icon;
+    }
+
+    if (iconUri) {
+      bookmark.iconUri = iconUri;
+    }
+
+    // Add bookmark to the tree.
+    frame.folder.children.push(bookmark);
+    frame.previousItem = bookmark;
+  },
+
+  _handleContainerBegin: function handleContainerBegin() {
+    this._curFrame.containerNesting++;
+  },
+
+  /**
+   * Our "indent" count has decreased, and when we hit 0 that means that this
+   * container is complete and we need to pop back to the outer frame. Never
+   * pop the toplevel frame
+   */
+  _handleContainerEnd: function handleContainerEnd() {
+    let frame = this._curFrame;
+    if (frame.containerNesting > 0) {
+      frame.containerNesting--;
+    }
+    if (this._frames.length > 1 && frame.containerNesting == 0) {
+      this._frames.pop();
+    }
+  },
+
+  /**
+   * Creates the new frame for this heading now that we know the name of the
+   * container (tokens since the heading open tag will have been placed in
+   * previousText).
+   */
+  _handleHeadEnd: function handleHeadEnd() {
+    this._newFrame();
+  },
+
+  /**
+   * Saves the title for the given bookmark.
+   */
+  _handleLinkEnd: function handleLinkEnd() {
+    let frame = this._curFrame;
+    frame.previousText = frame.previousText.trim();
+
+    if (frame.previousItem != null) {
+      frame.previousItem.title = frame.previousText;
+    }
+
+    frame.previousText = "";
+  },
+
+  _openContainer: function openContainer(aElt) {
+    if (aElt.namespaceURI != "http://www.w3.org/1999/xhtml") {
+      return;
+    }
+    switch (aElt.localName) {
+      case "h2":
+      case "h3":
+      case "h4":
+      case "h5":
+      case "h6":
+        this._handleHeadBegin(aElt);
+        break;
+      case "a":
+        this._handleLinkBegin(aElt);
+        break;
+      case "dl":
+      case "ul":
+      case "menu":
+        this._handleContainerBegin();
+        break;
+      case "dd":
+        this._curFrame.inDescription = true;
+        break;
+      case "hr":
+        this._handleSeparator(aElt);
+        break;
+    }
+  },
+
+  _closeContainer: function closeContainer(aElt) {
+    let frame = this._curFrame;
+
+    // Although we no longer support importing descriptions, we still need to
+    // clear any previous text, so that it doesn't get swallowed into other elements.
+    if (frame.inDescription) {
+      frame.previousText = "";
+      frame.inDescription = false;
+    }
+
+    if (aElt.namespaceURI != "http://www.w3.org/1999/xhtml") {
+      return;
+    }
+    switch (aElt.localName) {
+      case "dl":
+      case "ul":
+      case "menu":
+        this._handleContainerEnd();
+        break;
+      case "dt":
+        break;
+      case "h1":
+        // ignore
+        break;
+      case "h2":
+      case "h3":
+      case "h4":
+      case "h5":
+      case "h6":
+        this._handleHeadEnd();
+        break;
+      case "a":
+        this._handleLinkEnd();
+        break;
+      default:
+        break;
+    }
+  },
+
+  _appendText: function appendText(str) {
+    this._curFrame.previousText += str;
+  },
+
+  /**
+   * Converts a string date in seconds to a date object
+   */
+  _convertImportedDateToInternalDate:
+    function convertImportedDateToInternalDate(aDate) {
+      try {
+        if (aDate && !isNaN(aDate)) {
+          return new Date(parseInt(aDate) * 1000); // in bookmarks.html this value is in seconds
+        }
+      } catch (ex) {
+        // Do nothing.
+      }
+      return new Date();
+    },
+
+  _walkTreeForImport(aDoc) {
+    if (!aDoc) {
+      return;
+    }
+
+    let current = aDoc;
+    let next;
+    for (;;) {
+      switch (current.nodeType) {
+        case current.ELEMENT_NODE:
+          this._openContainer(current);
+          break;
+        case current.TEXT_NODE:
+          this._appendText(current.data);
+          break;
+      }
+      if ((next = current.firstChild)) {
+        current = next;
+        continue;
+      }
+      for (;;) {
+        if (current.nodeType == current.ELEMENT_NODE) {
+          this._closeContainer(current);
+        }
+        if (current == aDoc) {
+          return;
+        }
+        if ((next = current.nextSibling)) {
+          current = next;
+          break;
+        }
+        current = current.parentNode;
+      }
+    }
+  },
+
+  /**
+   * Returns the bookmark tree(s) from the importer. These are suitable for
+   * passing to PlacesUtils.bookmarks.insertTree().
+   *
+   * @returns {Array} An array of bookmark trees.
+   */
+  _getBookmarkTrees() {
+    // If we're not importing defaults, then everything gets imported under the
+    // Bookmarks menu.
+    if (!this._isImportDefaults) {
+      return [this._bookmarkTree];
+    }
+
+    // If we are importing defaults, we need to separate out the top-level
+    // default folders into separate items, for the caller to pass into insertTree.
+    let bookmarkTrees = [this._bookmarkTree];
+
+    // The children of this "root" element will contain normal children of the
+    // bookmark menu as well as the places roots. Hence, we need to filter out
+    // the separate roots, but keep the children that are relevant to the
+    // bookmark menu.
+    this._bookmarkTree.children = this._bookmarkTree.children.filter(child => {
+      if (
+        child.guid &&
+        PlacesUtils.bookmarks.userContentRoots.includes(child.guid)
+      ) {
+        bookmarkTrees.push(child);
+        return false;
+      }
+      return true;
+    });
+
+    return bookmarkTrees;
+  },
+
+  /**
+   * Imports the bookmarks from the importer into the places database.
+   *
+   * @param {BookmarkImporter} importer The importer from which to get the
+   *                                    bookmark information.
+   * @returns {number} The number of imported bookmarks, not including
+   *                   folders and separators
+   */
+  async _importBookmarks() {
+    if (this._isImportDefaults) {
+      await PlacesUtils.bookmarks.eraseEverything();
+    }
+
+    let bookmarksTrees = this._getBookmarkTrees();
+    let bookmarkCount = 0;
+    for (let tree of bookmarksTrees) {
+      if (!tree.children.length) {
+        continue;
+      }
+
+      // Give the tree the source.
+      tree.source = this._source;
+      let bookmarks = await PlacesUtils.bookmarks.insertTree(tree, {
+        fixupOrSkipInvalidEntries: true,
+      });
+      // We want to count only bookmarks, not folders or separators
+      bookmarkCount += bookmarks.filter(
+        bookmark => bookmark.type == PlacesUtils.bookmarks.TYPE_BOOKMARK
+      ).length;
+      insertFaviconsForTree(tree);
+    }
+    return bookmarkCount;
+  },
+
+  /**
+   * Imports data into the places database from the supplied url.
+   *
+   * @param {String} href The url to import data from.
+   * @returns {number} The number of imported bookmarks, not including
+   *                   folders and separators.
+   */
+  async importFromURL(href) {
+    let data = await fetchData(href);
+
+    if (this._isImportDefaults && data) {
+      // Localize default bookmarks.  Find rel="localization" links and manually
+      // localize using them.
+      let hrefs = [];
+      let links = data.head.querySelectorAll("link[rel='localization']");
+      for (let link of links) {
+        if (link.getAttribute("href")) {
+          // We need the text, not the fully qualified URL, so we use `getAttribute`.
+          hrefs.push(link.getAttribute("href"));
+        }
+      }
+
+      if (hrefs.length) {
+        let domLoc = new DOMLocalization(hrefs);
+        await domLoc.translateFragment(data.body);
+      }
+    }
+
+    this._walkTreeForImport(data);
+    return this._importBookmarks();
+  },
+};
+
+function BookmarkExporter(aBookmarksTree) {
+  // Create a map of the roots.
+  let rootsMap = new Map();
+  for (let child of aBookmarksTree.children) {
+    if (child.root) {
+      rootsMap.set(child.root, child);
+      // Also take the opportunity to get the correctly localised title for the
+      // root.
+      child.title = PlacesUtils.bookmarks.getLocalizedTitle(child);
+    }
+  }
+
+  // For backwards compatibility reasons the bookmarks menu is the root, while
+  // the bookmarks toolbar and unfiled bookmarks will be child items.
+  this._root = rootsMap.get("bookmarksMenuFolder");
+
+  for (let key of ["toolbarFolder", "unfiledBookmarksFolder"]) {
+    let root = rootsMap.get(key);
+    if (root.children && root.children.length) {
+      if (!this._root.children) {
+        this._root.children = [];
+      }
+      this._root.children.push(root);
+    }
+  }
+}
+
+BookmarkExporter.prototype = {
+  exportToFile: function exportToFile(aFilePath) {
+    return (async () => {
+      // Create a file that can be accessed by the current user only.
+      let out = FileUtils.openAtomicFileOutputStream(
+        new FileUtils.File(aFilePath)
+      );
+      try {
+        // We need a buffered output stream for performance.  See bug 202477.
+        let bufferedOut = Cc[
+          "@mozilla.org/network/buffered-output-stream;1"
+        ].createInstance(Ci.nsIBufferedOutputStream);
+        bufferedOut.init(out, 4096);
+        try {
+          // Write bookmarks in UTF-8.
+          this._converterOut = Cc[
+            "@mozilla.org/intl/converter-output-stream;1"
+          ].createInstance(Ci.nsIConverterOutputStream);
+          this._converterOut.init(bufferedOut, "utf-8");
+          try {
+            this._writeHeader();
+            await this._writeContainer(this._root);
+            // Retain the target file on success only.
+            bufferedOut.QueryInterface(Ci.nsISafeOutputStream).finish();
+          } finally {
+            this._converterOut.close();
+            this._converterOut = null;
+          }
+        } finally {
+          bufferedOut.close();
+        }
+      } finally {
+        out.close();
+      }
+    })();
+  },
+
+  _converterOut: null,
+
+  _write(aText) {
+    this._converterOut.writeString(aText || "");
+  },
+
+  _writeAttribute(aName, aValue) {
+    this._write(" " + aName + '="' + aValue + '"');
+  },
+
+  _writeLine(aText) {
+    this._write(aText + "\n");
+  },
+
+  _writeHeader() {
+    this._writeLine("<!DOCTYPE NETSCAPE-Bookmark-file-1>");
+    this._writeLine("<!-- This is an automatically generated file.");
+    this._writeLine("     It will be read and overwritten.");
+    this._writeLine("     DO NOT EDIT! -->");
+    this._writeLine(
+      '<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">'
+    );
+    this._writeLine(`<meta http-equiv="Content-Security-Policy"
+      content="default-src 'self'; script-src 'none'; img-src data: *; object-src 'none'"></meta>`);
+    this._writeLine("<TITLE>Bookmarks</TITLE>");
+  },
+
+  async _writeContainer(aItem, aIndent = "") {
+    if (aItem == this._root) {
+      this._writeLine("<H1>" + escapeHtmlEntities(this._root.title) + "</H1>");
+      this._writeLine("");
+    } else {
+      this._write(aIndent + "<DT><H3");
+      this._writeDateAttributes(aItem);
+
+      if (aItem.root === "toolbarFolder") {
+        this._writeAttribute("PERSONAL_TOOLBAR_FOLDER", "true");
+      } else if (aItem.root === "unfiledBookmarksFolder") {
+        this._writeAttribute("UNFILED_BOOKMARKS_FOLDER", "true");
+      }
+      this._writeLine(">" + escapeHtmlEntities(aItem.title) + "</H3>");
+    }
+
+    this._writeLine(aIndent + "<DL><p>");
+    if (aItem.children) {
+      await this._writeContainerContents(aItem, aIndent);
+    }
+    if (aItem == this._root) {
+      this._writeLine(aIndent + "</DL>");
+    } else {
+      this._writeLine(aIndent + "</DL><p>");
+    }
+  },
+
+  async _writeContainerContents(aItem, aIndent) {
+    let localIndent = aIndent + EXPORT_INDENT;
+
+    for (let child of aItem.children) {
+      if (child.type == PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER) {
+        await this._writeContainer(child, localIndent);
+      } else if (child.type == PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR) {
+        this._writeSeparator(child, localIndent);
+      } else {
+        await this._writeItem(child, localIndent);
+      }
+    }
+  },
+
+  _writeSeparator(aItem, aIndent) {
+    this._write(aIndent + "<HR");
+    // We keep exporting separator titles, but don't support them anymore.
+    if (aItem.title) {
+      this._writeAttribute("NAME", escapeHtmlEntities(aItem.title));
+    }
+    this._write(">");
+  },
+
+  async _writeItem(aItem, aIndent) {
+    try {
+      NetUtil.newURI(aItem.uri);
+    } catch (ex) {
+      // If the item URI is invalid, skip the item instead of failing later.
+      return;
+    }
+
+    this._write(aIndent + "<DT><A");
+    this._writeAttribute("HREF", escapeUrl(aItem.uri));
+    this._writeDateAttributes(aItem);
+    await this._writeFaviconAttribute(aItem);
+
+    if (aItem.keyword) {
+      this._writeAttribute("SHORTCUTURL", escapeHtmlEntities(aItem.keyword));
+      if (aItem.postData) {
+        this._writeAttribute("POST_DATA", escapeHtmlEntities(aItem.postData));
+      }
+    }
+
+    if (aItem.charset) {
+      this._writeAttribute("LAST_CHARSET", escapeHtmlEntities(aItem.charset));
+    }
+    if (aItem.tags) {
+      this._writeAttribute("TAGS", escapeHtmlEntities(aItem.tags));
+    }
+    this._writeLine(">" + escapeHtmlEntities(aItem.title) + "</A>");
+  },
+
+  _writeDateAttributes(aItem) {
+    if (aItem.dateAdded) {
+      this._writeAttribute(
+        "ADD_DATE",
+        Math.floor(aItem.dateAdded / MICROSEC_PER_SEC)
+      );
+    }
+    if (aItem.lastModified) {
+      this._writeAttribute(
+        "LAST_MODIFIED",
+        Math.floor(aItem.lastModified / MICROSEC_PER_SEC)
+      );
+    }
+  },
+
+  async _writeFaviconAttribute(aItem) {
+    if (!aItem.iconUri) {
+      return;
+    }
+    let favicon;
+    try {
+      favicon = await PlacesUtils.promiseFaviconData(aItem.uri);
+    } catch (ex) {
+      console.error("Unexpected Error trying to fetch icon data");
+      return;
+    }
+
+    this._writeAttribute("ICON_URI", escapeUrl(favicon.uri.spec));
+
+    if (!favicon.uri.schemeIs("chrome") && favicon.dataLen > 0) {
+      let faviconContents =
+        "data:image/png;base64," +
+        base64EncodeString(String.fromCharCode.apply(String, favicon.data));
+      this._writeAttribute("ICON", faviconContents);
+    }
+  },
+};
+
+/**
+ * Handles inserting favicons into the database for a bookmark node.
+ * It is assumed the node has already been inserted into the bookmarks
+ * database.
+ *
+ * @param {Object} node The bookmark node for icons to be inserted.
+ */
+function insertFaviconForNode(node) {
+  if (node.icon) {
+    try {
+      // Create a fake faviconURI to use (FIXME: bug 523932)
+      let faviconURI = Services.io.newURI("fake-favicon-uri:" + node.url);
+      PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+        faviconURI,
+        node.icon,
+        0,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+      PlacesUtils.favicons.setAndFetchFaviconForPage(
+        Services.io.newURI(node.url),
+        faviconURI,
+        false,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    } catch (ex) {
+      console.error("Failed to import favicon data:", ex);
+    }
+  }
+
+  if (!node.iconUri) {
+    return;
+  }
+
+  try {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      Services.io.newURI(node.url),
+      Services.io.newURI(node.iconUri),
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      null,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  } catch (ex) {
+    console.error("Failed to import favicon URI:" + ex);
+  }
+}
+
+/**
+ * Handles inserting favicons into the database for a bookmark tree - a node
+ * and its children.
+ *
+ * It is assumed the nodes have already been inserted into the bookmarks
+ * database.
+ *
+ * @param {Object} nodeTree The bookmark node tree for icons to be inserted.
+ */
+function insertFaviconsForTree(nodeTree) {
+  insertFaviconForNode(nodeTree);
+
+  if (nodeTree.children) {
+    for (let child of nodeTree.children) {
+      insertFaviconsForTree(child);
+    }
+  }
+}
+
+/**
+ * Handles fetching data from a URL.
+ *
+ * @param {String} href The url to fetch data from.
+ * @return {Promise} Returns a promise that is resolved with the data once
+ *                   the fetch is complete, or is rejected if it fails.
+ */
+function fetchData(href) {
+  return new Promise((resolve, reject) => {
+    let xhr = new XMLHttpRequest();
+    xhr.onload = () => {
+      resolve(xhr.responseXML);
+    };
+    xhr.onabort =
+      xhr.onerror =
+      xhr.ontimeout =
+        () => {
+          reject(new Error("xmlhttprequest failed"));
+        };
+    xhr.open("GET", href);
+    xhr.responseType = "document";
+    xhr.overrideMimeType("text/html");
+    xhr.send();
+  });
+}
diff --git a/toolkit/components/places/BookmarkJSONUtils.sys.mjs b/toolkit/components/places/BookmarkJSONUtils.sys.mjs
new file mode 100644
index 0000000000..29967b5395
--- /dev/null
+++ b/toolkit/components/places/BookmarkJSONUtils.sys.mjs
@@ -0,0 +1,581 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { PlacesUtils } from "resource://gre/modules/PlacesUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesBackups: "resource://gre/modules/PlacesBackups.sys.mjs",
+});
+
+// This is used to translate old folder pseudonyms in queries with their newer
+// guids.
+const OLD_BOOKMARK_QUERY_TRANSLATIONS = {
+  PLACES_ROOT: PlacesUtils.bookmarks.rootGuid,
+  BOOKMARKS_MENU: PlacesUtils.bookmarks.menuGuid,
+  TAGS: PlacesUtils.bookmarks.tagsGuid,
+  UNFILED_BOOKMARKS: PlacesUtils.bookmarks.unfiledGuid,
+  TOOLBAR: PlacesUtils.bookmarks.toolbarGuid,
+  MOBILE_BOOKMARKS: PlacesUtils.bookmarks.mobileGuid,
+};
+
+/**
+ * Generates an hash for the given string.
+ *
+ * @note The generated hash is returned in base64 form.  Mind the fact base64
+ * is case-sensitive if you are going to reuse this code.
+ */
+function generateHash(aString) {
+  let cryptoHash = Cc["@mozilla.org/security/hash;1"].createInstance(
+    Ci.nsICryptoHash
+  );
+  cryptoHash.init(Ci.nsICryptoHash.MD5);
+  let stringStream = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(
+    Ci.nsIStringInputStream
+  );
+  stringStream.setUTF8Data(aString);
+  cryptoHash.updateFromStream(stringStream, -1);
+  // base64 allows the '/' char, but we can't use it for filenames.
+  return cryptoHash.finish(true).replace(/\//g, "-");
+}
+
+export var BookmarkJSONUtils = Object.freeze({
+  /**
+   * Import bookmarks from a url.
+   *
+   * @param {string} aSpec
+   *        url of the bookmark data.
+   * @param {boolean} [options.replace]
+   *        Whether we should erase existing bookmarks before importing.
+   * @param {PlacesUtils.bookmarks.SOURCES} [options.source]
+   *        The bookmark change source, used to determine the sync status for
+   *        imported bookmarks. Defaults to `RESTORE` if `replace = true`, or
+   *        `IMPORT` otherwise.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                            folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromURL(
+    aSpec,
+    {
+      replace: aReplace = false,
+      source: aSource = aReplace
+        ? PlacesUtils.bookmarks.SOURCES.RESTORE
+        : PlacesUtils.bookmarks.SOURCES.IMPORT,
+    } = {}
+  ) {
+    notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_BEGIN, aReplace);
+    let bookmarkCount = 0;
+    try {
+      let importer = new BookmarkImporter(aReplace, aSource);
+      bookmarkCount = await importer.importFromURL(aSpec);
+
+      notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_SUCCESS, aReplace);
+    } catch (ex) {
+      console.error(`Failed to restore bookmarks from ${aSpec}:`, ex);
+      notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_FAILED, aReplace);
+      throw ex;
+    }
+    return bookmarkCount;
+  },
+
+  /**
+   * Restores bookmarks and tags from a JSON file.
+   *
+   * @param aFilePath
+   *        OS.File path string of bookmarks in JSON or JSONlz4 format to be restored.
+   * @param [options.replace]
+   *        Whether we should erase existing bookmarks before importing.
+   * @param [options.source]
+   *        The bookmark change source, used to determine the sync status for
+   *        imported bookmarks. Defaults to `RESTORE` if `replace = true`, or
+   *        `IMPORT` otherwise.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                            folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromFile(
+    aFilePath,
+    {
+      replace: aReplace = false,
+      source: aSource = aReplace
+        ? PlacesUtils.bookmarks.SOURCES.RESTORE
+        : PlacesUtils.bookmarks.SOURCES.IMPORT,
+    } = {}
+  ) {
+    notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_BEGIN, aReplace);
+    let bookmarkCount = 0;
+    try {
+      if (!(await IOUtils.exists(aFilePath))) {
+        throw new Error("Cannot restore from nonexisting json file");
+      }
+
+      let importer = new BookmarkImporter(aReplace, aSource);
+      if (aFilePath.endsWith("jsonlz4")) {
+        bookmarkCount = await importer.importFromCompressedFile(aFilePath);
+      } else {
+        bookmarkCount = await importer.importFromURL(
+          PathUtils.toFileURI(aFilePath)
+        );
+      }
+      notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_SUCCESS, aReplace);
+    } catch (ex) {
+      console.error(`Failed to restore bookmarks from ${aFilePath}:`, ex);
+      notifyObservers(PlacesUtils.TOPIC_BOOKMARKS_RESTORE_FAILED, aReplace);
+      throw ex;
+    }
+    return bookmarkCount;
+  },
+
+  /**
+   * Serializes bookmarks using JSON, and writes to the supplied file path.
+   *
+   * @param {path} aFilePath
+   *   Path string for the bookmarks file to be created.
+   * @param {object} [aOptions]
+   * @param {string} [failIfHashIs]
+   *   If the generated file would have the same hash defined here, will reject
+   *   with ex.becauseSameHash
+   * @param {boolean} [compress]
+   *   If true, writes file using lz4 compression
+   * @return {Promise}
+   * @resolves once the file has been created, to an object with the
+   *           following properties:
+   *            - count: number of exported bookmarks
+   *            - hash: file hash for contents comparison
+   * @rejects JavaScript exception.
+   */
+  async exportToFile(aFilePath, aOptions = {}) {
+    let [bookmarks, count] = await lazy.PlacesBackups.getBookmarksTree();
+    let startTime = Date.now();
+    let jsonString = JSON.stringify(bookmarks);
+    // Report the time taken to convert the tree to JSON.
+    try {
+      Services.telemetry
+        .getHistogramById("PLACES_BACKUPS_TOJSON_MS")
+        .add(Date.now() - startTime);
+    } catch (ex) {
+      console.error("Unable to report telemetry.");
+    }
+
+    let hash = generateHash(jsonString);
+
+    if (hash === aOptions.failIfHashIs) {
+      let e = new Error("Hash conflict");
+      e.becauseSameHash = true;
+      throw e;
+    }
+
+    // Do not write to the tmp folder, otherwise if it has a different
+    // filesystem writeAtomic will fail.  Eventual dangling .tmp files should
+    // be cleaned up by the caller.
+    await IOUtils.writeUTF8(aFilePath, jsonString, {
+      compress: aOptions.compress,
+      tmpPath: PathUtils.join(aFilePath + ".tmp"),
+    });
+    return { count, hash };
+  },
+});
+
+function BookmarkImporter(aReplace, aSource) {
+  this._replace = aReplace;
+  this._source = aSource;
+}
+BookmarkImporter.prototype = {
+  /**
+   * Import bookmarks from a url.
+   *
+   * @param {string} aSpec
+   *        url of the bookmark data.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                            folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromURL(spec) {
+    if (!spec.startsWith("chrome://") && !spec.startsWith("file://")) {
+      throw new Error(
+        "importFromURL can only be used with chrome:// and file:// URLs"
+      );
+    }
+    let nodes = await (await fetch(spec)).json();
+
+    if (!nodes.children || !nodes.children.length) {
+      return 0;
+    }
+
+    return this.import(nodes);
+  },
+
+  /**
+   * Import bookmarks from a compressed file.
+   *
+   * @param aFilePath
+   *        OS.File path string of the bookmark data.
+   *
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                           folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  importFromCompressedFile: async function BI_importFromCompressedFile(
+    aFilePath
+  ) {
+    // We read as UTF8 rather than JSON, as PlacesUtils.unwrapNodes expects
+    // a JSON string.
+    let result = await IOUtils.readUTF8(aFilePath, { decompress: true });
+    return this.importFromJSON(result);
+  },
+
+  /**
+   * Import bookmarks from a JSON string.
+   *
+   * @param {String} aString JSON string of serialized bookmark data.
+   * @returns {Promise<number>} The number of imported bookmarks, not including
+   *                            folders and separators.
+   * @resolves When the new bookmarks have been created.
+   * @rejects JavaScript exception.
+   */
+  async importFromJSON(aString) {
+    let nodes = PlacesUtils.unwrapNodes(
+      aString,
+      PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER
+    );
+
+    if (!nodes.length || !nodes[0].children || !nodes[0].children.length) {
+      return 0;
+    }
+
+    return this.import(nodes[0]);
+  },
+
+  async import(rootNode) {
+    // Change to rootNode.children as we don't import the root, and also filter
+    // out any obsolete "tagsFolder" sections.
+    let nodes = rootNode.children.filter(node => node.root !== "tagsFolder");
+
+    // If we're replacing, then erase existing bookmarks first.
+    if (this._replace) {
+      await PlacesUtils.bookmarks.eraseEverything({ source: this._source });
+    }
+
+    let folderIdToGuidMap = {};
+
+    // Now do some cleanup on the imported nodes so that the various guids
+    // match what we need for insertTree, and we also have mappings of folders
+    // so we can repair any searches after inserting the bookmarks (see bug 824502).
+    for (let node of nodes) {
+      if (!node.children || !node.children.length) {
+        continue;
+      } // Nothing to restore for this root
+
+      // Ensure we set the source correctly.
+      node.source = this._source;
+
+      // Translate the node for insertTree.
+      let folders = translateTreeTypes(node);
+
+      folderIdToGuidMap = Object.assign(folderIdToGuidMap, folders);
+    }
+
+    let bookmarkCount = 0;
+    // Now we can add the actual nodes to the database.
+    for (let node of nodes) {
+      // Drop any nodes without children, we can't insert them.
+      if (!node.children || !node.children.length) {
+        continue;
+      }
+
+      // Drop any roots whose guid we don't recognise - we don't support anything
+      // apart from the built-in roots.
+      if (!PlacesUtils.bookmarks.userContentRoots.includes(node.guid)) {
+        continue;
+      }
+
+      fixupSearchQueries(node, folderIdToGuidMap);
+
+      let bookmarks = await PlacesUtils.bookmarks.insertTree(node, {
+        fixupOrSkipInvalidEntries: true,
+      });
+      // We want to count only bookmarks, not folders or separators
+      bookmarkCount += bookmarks.filter(
+        bookmark => bookmark.type == PlacesUtils.bookmarks.TYPE_BOOKMARK
+      ).length;
+      // Now add any favicons.
+      try {
+        insertFaviconsForTree(node);
+      } catch (ex) {
+        console.error("Failed to insert favicons:", ex);
+      }
+    }
+    return bookmarkCount;
+  },
+};
+
+function notifyObservers(topic, replace) {
+  Services.obs.notifyObservers(null, topic, replace ? "json" : "json-append");
+}
+
+/**
+ * Iterates through a node, fixing up any place: URL queries that are found. This
+ * replaces any old (pre Firefox 62) queries that contain "folder=<id>" parts with
+ * "parent=<guid>".
+ *
+ * @param {Object} aNode The node to search.
+ * @param {Array} aFolderIdMap An array mapping of old folder IDs to new folder GUIDs.
+ */
+function fixupSearchQueries(aNode, aFolderIdMap) {
+  if (aNode.url && aNode.url.startsWith("place:")) {
+    aNode.url = fixupQuery(aNode.url, aFolderIdMap);
+  }
+  if (aNode.children) {
+    for (let child of aNode.children) {
+      fixupSearchQueries(child, aFolderIdMap);
+    }
+  }
+}
+
+/**
+ * Replaces imported folder ids with their local counterparts in a place: URI.
+ *
+ * @param   {String} aQueryURL
+ *          A place: URI with folder ids.
+ * @param   {Object} aFolderIdMap
+ *          An array mapping of old folder IDs to new folder GUIDs.
+ * @return {String} the fixed up URI if all matched. If some matched, it returns
+ *         the URI with only the matching folders included. If none matched
+ *         it returns the input URI unchanged.
+ */
+function fixupQuery(aQueryURL, aFolderIdMap) {
+  let invalid = false;
+  let convert = function (str, existingFolderId) {
+    let guid;
+    if (
+      Object.keys(OLD_BOOKMARK_QUERY_TRANSLATIONS).includes(existingFolderId)
+    ) {
+      guid = OLD_BOOKMARK_QUERY_TRANSLATIONS[existingFolderId];
+    } else {
+      guid = aFolderIdMap[existingFolderId];
+      if (!guid) {
+        invalid = true;
+        return `invalidOldParentId=${existingFolderId}`;
+      }
+    }
+    return `parent=${guid}`;
+  };
+
+  let url = aQueryURL.replace(/folder=([A-Za-z0-9_]+)/g, convert);
+  if (invalid) {
+    // One or more of the folders don't exist, cause an empty query so that
+    // we don't try to display the whole database.
+    url += "&excludeItems=1";
+  }
+  return url;
+}
+
+/**
+ * A mapping of root folder names to Guids. To help fixupRootFolderGuid.
+ */
+const rootToFolderGuidMap = {
+  placesRoot: PlacesUtils.bookmarks.rootGuid,
+  bookmarksMenuFolder: PlacesUtils.bookmarks.menuGuid,
+  unfiledBookmarksFolder: PlacesUtils.bookmarks.unfiledGuid,
+  toolbarFolder: PlacesUtils.bookmarks.toolbarGuid,
+  mobileFolder: PlacesUtils.bookmarks.mobileGuid,
+};
+
+/**
+ * Updates a bookmark node from the json version to the places GUID. This
+ * will only change GUIDs for the built-in folders. Other folders will remain
+ * unchanged.
+ *
+ * @param {Object} A bookmark node that is updated with the new GUID if necessary.
+ */
+function fixupRootFolderGuid(node) {
+  if (!node.guid && node.root && node.root in rootToFolderGuidMap) {
+    node.guid = rootToFolderGuidMap[node.root];
+  }
+}
+
+/**
+ * Translates the JSON types for a node and its children into Places compatible
+ * types. Also handles updating of other parameters e.g. dateAdded and lastModified.
+ *
+ * @param {Object} node A node to be updated. If it contains children, they will
+ *                      be updated as well.
+ * @return {Array} An array containing two items:
+ *       - {Object} A map of current folder ids to GUIDS
+ *       - {Array} An array of GUIDs for nodes that contain query URIs
+ */
+function translateTreeTypes(node) {
+  let folderIdToGuidMap = {};
+
+  // Do the uri fixup first, so we can be consistent in this function.
+  if (node.uri) {
+    node.url = node.uri;
+    delete node.uri;
+  }
+
+  switch (node.type) {
+    case PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER:
+      node.type = PlacesUtils.bookmarks.TYPE_FOLDER;
+
+      // Older type mobile folders have a random guid with an annotation. We need
+      // to make sure those go into the proper mobile folder.
+      let isMobileFolder =
+        node.annos &&
+        node.annos.some(anno => anno.name == PlacesUtils.MOBILE_ROOT_ANNO);
+      if (isMobileFolder) {
+        node.guid = PlacesUtils.bookmarks.mobileGuid;
+      } else {
+        // In case the Guid is broken, we need to fix it up.
+        fixupRootFolderGuid(node);
+      }
+
+      // Record the current id and the guid so that we can update any search
+      // queries later.
+      folderIdToGuidMap[node.id] = node.guid;
+      break;
+    case PlacesUtils.TYPE_X_MOZ_PLACE:
+      node.type = PlacesUtils.bookmarks.TYPE_BOOKMARK;
+      break;
+    case PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR:
+      node.type = PlacesUtils.bookmarks.TYPE_SEPARATOR;
+      if ("title" in node) {
+        delete node.title;
+      }
+      break;
+    default:
+      // No need to throw/reject here, insertTree will remove this node automatically.
+      console.error("Unexpected bookmark type", node.type);
+      break;
+  }
+
+  if (node.dateAdded) {
+    node.dateAdded = PlacesUtils.toDate(node.dateAdded);
+  }
+
+  if (node.lastModified) {
+    let lastModified = PlacesUtils.toDate(node.lastModified);
+    // Ensure we get a last modified date that's later or equal to the dateAdded
+    // so that we don't upset the Bookmarks API.
+    if (lastModified >= node.dateAdded) {
+      node.lastModified = lastModified;
+    } else {
+      delete node.lastModified;
+    }
+  }
+
+  if (node.tags) {
+    // Separate any tags into an array, and ignore any that are too long.
+    node.tags = node.tags
+      .split(",")
+      .filter(
+        aTag =>
+          !!aTag.length && aTag.length <= PlacesUtils.bookmarks.MAX_TAG_LENGTH
+      );
+
+    // If we end up with none, then delete the property completely.
+    if (!node.tags.length) {
+      delete node.tags;
+    }
+  }
+
+  // Sometimes postData can be null, so delete it to make the validators happy.
+  if (node.postData == null) {
+    delete node.postData;
+  }
+
+  // Now handle any children.
+  if (!node.children) {
+    return folderIdToGuidMap;
+  }
+
+  // First sort the children by index.
+  node.children = node.children.sort((a, b) => {
+    return a.index - b.index;
+  });
+
+  // Now do any adjustments required for the children.
+  for (let child of node.children) {
+    let folders = translateTreeTypes(child);
+    folderIdToGuidMap = Object.assign(folderIdToGuidMap, folders);
+  }
+
+  return folderIdToGuidMap;
+}
+
+/**
+ * Handles inserting favicons into the database for a bookmark node.
+ * It is assumed the node has already been inserted into the bookmarks
+ * database.
+ *
+ * @param {Object} node The bookmark node for icons to be inserted.
+ */
+function insertFaviconForNode(node) {
+  if (node.icon) {
+    try {
+      // Create a fake faviconURI to use (FIXME: bug 523932)
+      let faviconURI = Services.io.newURI("fake-favicon-uri:" + node.url);
+      PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+        faviconURI,
+        node.icon,
+        0,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+      PlacesUtils.favicons.setAndFetchFaviconForPage(
+        Services.io.newURI(node.url),
+        faviconURI,
+        false,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    } catch (ex) {
+      console.error("Failed to import favicon data:", ex);
+    }
+  }
+
+  if (!node.iconUri) {
+    return;
+  }
+
+  try {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      Services.io.newURI(node.url),
+      Services.io.newURI(node.iconUri),
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      null,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  } catch (ex) {
+    console.error("Failed to import favicon URI:" + ex);
+  }
+}
+
+/**
+ * Handles inserting favicons into the database for a bookmark tree - a node
+ * and its children.
+ *
+ * It is assumed the nodes have already been inserted into the bookmarks
+ * database.
+ *
+ * @param {Object} nodeTree The bookmark node tree for icons to be inserted.
+ */
+function insertFaviconsForTree(nodeTree) {
+  insertFaviconForNode(nodeTree);
+
+  if (nodeTree.children) {
+    for (let child of nodeTree.children) {
+      insertFaviconsForTree(child);
+    }
+  }
+}
diff --git a/toolkit/components/places/Bookmarks.sys.mjs b/toolkit/components/places/Bookmarks.sys.mjs
new file mode 100644
index 0000000000..7f9a397c34
--- /dev/null
+++ b/toolkit/components/places/Bookmarks.sys.mjs
@@ -0,0 +1,3385 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This module provides an asynchronous API for managing bookmarks.
+ *
+ * Bookmarks are organized in a tree structure, and include URLs, folders and
+ * separators.  Multiple bookmarks for the same URL are allowed.
+ *
+ * Note that if you are handling bookmarks operations in the UI, you should
+ * not use this API directly, but rather use PlacesTransactions, so that
+ * any operation is undo/redo-able.
+ *
+ * Each bookmark-item is represented by an object having the following
+ * properties:
+ *
+ *  - guid (string)
+ *      The globally unique identifier of the item.
+ *  - parentGuid (string)
+ *      The globally unique identifier of the folder containing the item.
+ *      This will be an empty string for the Places root folder.
+ *  - index (number)
+ *      The 0-based position of the item in the parent folder.
+ *  - dateAdded (Date)
+ *      The time at which the item was added.
+ *  - lastModified (Date)
+ *      The time at which the item was last modified.
+ *  - type (number)
+ *      The item's type, either TYPE_BOOKMARK, TYPE_FOLDER or TYPE_SEPARATOR.
+ *
+ *  The following properties are only valid for URLs or folders.
+ *
+ *  - title (string)
+ *      The item's title, if any.  Empty titles and null titles are considered
+ *      the same. Titles longer than DB_TITLE_LENGTH_MAX will be truncated.
+ *
+ *  The following properties are only valid for URLs:
+ *
+ *  - url (URL, href or nsIURI)
+ *      The item's URL.  Note that while input objects can contains either
+ *      an URL object, an href string, or an nsIURI, output objects will always
+ *      contain an URL object.
+ *      An URL cannot be longer than DB_URL_LENGTH_MAX, methods will throw if a
+ *      longer value is provided.
+ *
+ * Each successful operation notifies through the PlacesObservers
+ * interface.  To listen to such notifications you must register using
+ * PlacesUtils.observers.addListener and PlacesUtils.observers.removeListener
+ * methods.
+ * Note that bookmark addition or order changes won't notify bookmark-moved for
+ * items that have their indexes changed.
+ * Similarly, lastModified changes not done explicitly (like changing another
+ * property) won't fire a bookmark-time-changed notification.
+ * @see PlacesObservers
+ */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  NetUtil: "resource://gre/modules/NetUtil.sys.mjs",
+  PlacesSyncUtils: "resource://gre/modules/PlacesSyncUtils.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+const MATCH_ANYWHERE_UNMODIFIED =
+  Ci.mozIPlacesAutoComplete.MATCH_ANYWHERE_UNMODIFIED;
+const BEHAVIOR_BOOKMARK = Ci.mozIPlacesAutoComplete.BEHAVIOR_BOOKMARK;
+
+export var Bookmarks = Object.freeze({
+  /**
+   * Item's type constants.
+   * These should stay consistent with nsINavBookmarksService.idl
+   */
+  TYPE_BOOKMARK: 1,
+  TYPE_FOLDER: 2,
+  TYPE_SEPARATOR: 3,
+
+  /**
+   * Sync status constants, stored for each item.
+   */
+  SYNC_STATUS: {
+    UNKNOWN: Ci.nsINavBookmarksService.SYNC_STATUS_UNKNOWN,
+    NEW: Ci.nsINavBookmarksService.SYNC_STATUS_NEW,
+    NORMAL: Ci.nsINavBookmarksService.SYNC_STATUS_NORMAL,
+  },
+
+  /**
+   * Default index used to append a bookmark-item at the end of a folder.
+   * This should stay consistent with nsINavBookmarksService.idl
+   */
+  DEFAULT_INDEX: -1,
+
+  /**
+   * Maximum length of a tag.
+   * Any tag above this length is rejected.
+   */
+  MAX_TAG_LENGTH: 100,
+
+  /**
+   * Bookmark change source constants, passed as optional properties and
+   * forwarded to observers. See nsINavBookmarksService.idl for an explanation.
+   */
+  SOURCES: {
+    DEFAULT: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+    SYNC: Ci.nsINavBookmarksService.SOURCE_SYNC,
+    IMPORT: Ci.nsINavBookmarksService.SOURCE_IMPORT,
+    SYNC_REPARENT_REMOVED_FOLDER_CHILDREN:
+      Ci.nsINavBookmarksService.SOURCE_SYNC_REPARENT_REMOVED_FOLDER_CHILDREN,
+    RESTORE: Ci.nsINavBookmarksService.SOURCE_RESTORE,
+    RESTORE_ON_STARTUP: Ci.nsINavBookmarksService.SOURCE_RESTORE_ON_STARTUP,
+  },
+
+  /**
+   * Special GUIDs associated with bookmark roots.
+   * It's guaranteed that the roots will always have these guids.
+   */
+  rootGuid: "root________",
+  menuGuid: "menu________",
+  toolbarGuid: "toolbar_____",
+  unfiledGuid: "unfiled_____",
+  mobileGuid: "mobile______",
+
+  // With bug 424160, tags will stop being bookmarks, thus this root will
+  // be removed.  Do not rely on this, rather use the tagging service API.
+  tagsGuid: "tags________",
+
+  /**
+   * The GUIDs of the user content root folders that we support, for easy access
+   * as a set.
+   */
+  userContentRoots: [
+    "toolbar_____",
+    "menu________",
+    "unfiled_____",
+    "mobile______",
+  ],
+
+  /**
+   * GUID associated with bookmarks that haven't been saved to the database yet.
+   */
+  unsavedGuid: "new_________",
+
+  /**
+   * GUIDs associated with virtual queries that are used for displaying bookmark
+   * folders in the left pane.
+   */
+  virtualMenuGuid: "menu_______v",
+  virtualToolbarGuid: "toolbar____v",
+  virtualUnfiledGuid: "unfiled____v",
+  virtualMobileGuid: "mobile_____v",
+
+  /**
+   * Checks if a guid is a virtual root.
+   *
+   * @param {String} guid The guid of the item to look for.
+   * @returns {Boolean} true if guid is a virtual root, false otherwise.
+   */
+  isVirtualRootItem(guid) {
+    return (
+      guid == lazy.PlacesUtils.bookmarks.virtualMenuGuid ||
+      guid == lazy.PlacesUtils.bookmarks.virtualToolbarGuid ||
+      guid == lazy.PlacesUtils.bookmarks.virtualUnfiledGuid ||
+      guid == lazy.PlacesUtils.bookmarks.virtualMobileGuid
+    );
+  },
+
+  /**
+   * Returns the title to use on the UI for a bookmark item. Root folders
+   * in the database don't store fully localised versions of the title. To
+   * get those this function should be called.
+   *
+   * Hence, this function should only be called if a root folder object is
+   * likely to be displayed to the user.
+   *
+   * @param {Object} info An object representing a bookmark-item.
+   * @returns {String} The correct string.
+   * @throws {Error} If the guid in PlacesUtils.bookmarks.userContentRoots is
+   *                 not supported.
+   */
+  getLocalizedTitle(info) {
+    if (!lazy.PlacesUtils.bookmarks.userContentRoots.includes(info.guid)) {
+      return info.title;
+    }
+
+    switch (info.guid) {
+      case lazy.PlacesUtils.bookmarks.toolbarGuid:
+        return lazy.PlacesUtils.getString("BookmarksToolbarFolderTitle");
+      case lazy.PlacesUtils.bookmarks.menuGuid:
+        return lazy.PlacesUtils.getString("BookmarksMenuFolderTitle");
+      case lazy.PlacesUtils.bookmarks.unfiledGuid:
+        return lazy.PlacesUtils.getString("OtherBookmarksFolderTitle");
+      case lazy.PlacesUtils.bookmarks.mobileGuid:
+        return lazy.PlacesUtils.getString("MobileBookmarksFolderTitle");
+      default:
+        throw new Error(
+          `Unsupported guid ${info.guid} passed to getLocalizedTitle!`
+        );
+    }
+  },
+
+  /**
+   * Inserts a bookmark-item into the bookmarks tree.
+   *
+   * For creating a bookmark, the following set of properties is required:
+   *  - type
+   *  - parentGuid
+   *  - url, only for bookmarked URLs
+   *
+   * If an index is not specified, it defaults to appending.
+   * It's also possible to pass a non-existent GUID to force creation of an
+   * item with the given GUID, but unless you have a very sound reason, such as
+   * an undo manager implementation or synchronization, don't do that.
+   *
+   * Note that any known properties that don't apply to the specific item type
+   * cause an exception.
+   *
+   * @param info
+   *        object representing a bookmark-item.
+   *
+   * @return {Promise} resolved when the creation is complete.
+   * @resolves to an object representing the created bookmark.
+   * @rejects if it's not possible to create the requested bookmark.
+   * @throws if the arguments are invalid.
+   */
+  insert(info) {
+    let now = new Date();
+    let addedTime = (info && info.dateAdded) || now;
+    let modTime = addedTime;
+    if (addedTime > now) {
+      modTime = now;
+    }
+    let insertInfo = validateBookmarkObject("Bookmarks.jsm: insert", info, {
+      type: { defaultValue: this.TYPE_BOOKMARK },
+      index: { defaultValue: this.DEFAULT_INDEX },
+      url: {
+        requiredIf: b => b.type == this.TYPE_BOOKMARK,
+        validIf: b => b.type == this.TYPE_BOOKMARK,
+      },
+      parentGuid: {
+        required: true,
+        // Inserting into the root folder is not allowed unless it's testing.
+        validIf: b =>
+          lazy.PlacesUtils.isInAutomation || b.parentGuid != this.rootGuid,
+      },
+      title: {
+        defaultValue: "",
+        validIf: b =>
+          b.type == this.TYPE_BOOKMARK ||
+          b.type == this.TYPE_FOLDER ||
+          b.title === "",
+      },
+      dateAdded: { defaultValue: addedTime },
+      lastModified: {
+        defaultValue: modTime,
+        validIf: b =>
+          b.lastModified >= now ||
+          (b.dateAdded && b.lastModified >= b.dateAdded),
+      },
+      source: { defaultValue: this.SOURCES.DEFAULT },
+    });
+
+    return (async () => {
+      // Ensure the parent exists.
+      let parent = await fetchBookmark({ guid: insertInfo.parentGuid });
+      if (!parent) {
+        throw new Error("parentGuid must be valid");
+      }
+
+      // Set index in the appending case.
+      if (
+        insertInfo.index == this.DEFAULT_INDEX ||
+        insertInfo.index > parent._childCount
+      ) {
+        insertInfo.index = parent._childCount;
+      }
+
+      let item = await insertBookmark(insertInfo, parent);
+      let itemDetailMap = await getBookmarkDetailMap([item.guid]);
+      let itemDetail = itemDetailMap.get(item.guid);
+
+      // Pass tagging information for the observers to skip over these notifications when needed.
+      let isTagging = parent._parentId == lazy.PlacesUtils.tagsFolderId;
+      let isTagsFolder = parent._id == lazy.PlacesUtils.tagsFolderId;
+      let url = "";
+      if (item.type == Bookmarks.TYPE_BOOKMARK) {
+        url = item.url.href;
+      }
+
+      const notifications = [
+        new PlacesBookmarkAddition({
+          id: itemDetail.id,
+          url,
+          itemType: item.type,
+          parentId: parent._id,
+          index: item.index,
+          title: item.title,
+          dateAdded: item.dateAdded,
+          guid: item.guid,
+          parentGuid: item.parentGuid,
+          source: item.source,
+          isTagging: isTagging || isTagsFolder,
+          tags: itemDetail.tags,
+          frecency: itemDetail.frecency,
+          hidden: itemDetail.hidden,
+          visitCount: itemDetail.visitCount,
+          lastVisitDate: itemDetail.lastVisitDate,
+          targetFolderGuid: itemDetail.targetFolderGuid,
+          targetFolderItemId: itemDetail.targetFolderItemId,
+          targetFolderTitle: itemDetail.targetFolderTitle,
+        }),
+      ];
+
+      // If it's a tag, notify bookmark-tags-changed event to all bookmarks for this URL.
+      if (isTagging) {
+        for (let entry of await fetchBookmarksByURL(item, {
+          concurrent: true,
+        })) {
+          notifications.push(
+            new PlacesBookmarkTags({
+              id: entry._id,
+              itemType: entry.type,
+              url,
+              guid: entry.guid,
+              parentGuid: entry.parentGuid,
+              tags: entry._tags,
+              lastModified: entry.lastModified,
+              source: item.source,
+              isTagging: false,
+            })
+          );
+        }
+      }
+
+      PlacesObservers.notifyListeners(notifications);
+
+      // Remove non-enumerable properties.
+      delete item.source;
+      return Object.assign({}, item);
+    })();
+  },
+
+  /**
+   * Inserts a bookmark-tree into the existing bookmarks tree.
+   *
+   * All the specified folders and bookmarks will be inserted as new, even
+   * if duplicates. There's no merge support at this time.
+   *
+   * The input should be of the form:
+   * {
+   *   guid: "<some-existing-guid-to-use-as-parent>",
+   *   source: "<some valid source>", (optional)
+   *   children: [
+   *     ... valid bookmark objects.
+   *   ]
+   * }
+   *
+   * Children will be appended to any existing children of the parent
+   * that is specified. The source specified on the root of the tree
+   * will be used for all the items inserted. Any indices or custom parentGuids
+   * set on children will be ignored and overwritten.
+   *
+   * @param {Object} tree
+   *        object representing a tree of bookmark items to insert.
+   * @param {Object} options [optional]
+   *        object with properties representing options.  Current options are:
+   *         - fixupOrSkipInvalidEntries: makes the insert more lenient to
+   *           mistakes in the input tree.  Properties of an entry that are
+   *           fixable will be corrected, otherwise the entry will be skipped.
+   *           This is particularly convenient for import/restore operations,
+   *           but should not be abused for common inserts, since it may hide
+   *           bugs in the calling code.
+   *
+   * @return {Promise} resolved when the creation is complete.
+   * @resolves to an array of objects representing the created bookmark(s).
+   * @rejects if it's not possible to create the requested bookmark.
+   * @throws if the arguments are invalid.
+   */
+  insertTree(tree, options) {
+    if (!tree || typeof tree != "object") {
+      throw new Error("Should be provided a valid tree object.");
+    }
+    if (!Array.isArray(tree.children) || !tree.children.length) {
+      throw new Error("Should have a non-zero number of children to insert.");
+    }
+    if (!lazy.PlacesUtils.isValidGuid(tree.guid)) {
+      throw new Error(
+        `The parent guid is not valid (${tree.guid} ${tree.title}).`
+      );
+    }
+    if (tree.guid == this.rootGuid) {
+      throw new Error("Can't insert into the root.");
+    }
+    if (tree.guid == this.tagsGuid) {
+      throw new Error("Can't use insertTree to insert tags.");
+    }
+    if (
+      tree.hasOwnProperty("source") &&
+      !Object.values(this.SOURCES).includes(tree.source)
+    ) {
+      throw new Error("Can't use source value " + tree.source);
+    }
+    if (options && typeof options != "object") {
+      throw new Error("Options should be a valid object");
+    }
+    let fixupOrSkipInvalidEntries =
+      options && !!options.fixupOrSkipInvalidEntries;
+
+    // Serialize the tree into an array of items to insert into the db.
+    let insertInfos = [];
+    let urlsThatMightNeedPlaces = [];
+
+    // We want to use the same 'last added' time for all the entries
+    // we import (so they won't differ by a few ms based on where
+    // they are in the tree, and so we don't needlessly construct
+    // multiple dates).
+    let fallbackLastAdded = new Date();
+
+    const { TYPE_BOOKMARK, TYPE_FOLDER, SOURCES } = this;
+
+    // Reuse the 'source' property for all the entries.
+    let source = tree.source || SOURCES.DEFAULT;
+
+    // This is recursive.
+    function appendInsertionInfoForInfoArray(infos, indexToUse, parentGuid) {
+      // We want to keep the index of items that will be inserted into the root
+      // NULL, and then use a subquery to select the right index, to avoid
+      // races where other consumers might add items between when we determine
+      // the index and when we insert. However, the validator does not allow
+      // NULL values in in the index, so we fake it while validating and then
+      // correct later. Keep track of whether we're doing this:
+      let shouldUseNullIndices = false;
+      if (indexToUse === null) {
+        shouldUseNullIndices = true;
+        indexToUse = 0;
+      }
+
+      // When a folder gets an item added, its last modified date is updated
+      // to be equal to the date we added the item (if that date is newer).
+      // Because we're inserting a tree, we keep track of this date for the
+      // loop, updating it for inserted items as well as from any subfolders
+      // we insert.
+      let lastAddedForParent = new Date(0);
+      for (let info of infos) {
+        // Ensure to use the same date for dateAdded and lastModified, even if
+        // dateAdded may be imposed by the caller.
+        let time = (info && info.dateAdded) || fallbackLastAdded;
+        let insertInfo = {
+          guid: { defaultValue: lazy.PlacesUtils.history.makeGuid() },
+          type: { defaultValue: TYPE_BOOKMARK },
+          url: {
+            requiredIf: b => b.type == TYPE_BOOKMARK,
+            validIf: b => b.type == TYPE_BOOKMARK,
+          },
+          parentGuid: { replaceWith: parentGuid }, // Set the correct parent guid.
+          title: {
+            defaultValue: "",
+            validIf: b =>
+              b.type == TYPE_BOOKMARK ||
+              b.type == TYPE_FOLDER ||
+              b.title === "",
+          },
+          dateAdded: {
+            defaultValue: time,
+            validIf: b => !b.lastModified || b.dateAdded <= b.lastModified,
+          },
+          lastModified: {
+            defaultValue: time,
+            validIf: b =>
+              (!b.dateAdded && b.lastModified >= time) ||
+              (b.dateAdded && b.lastModified >= b.dateAdded),
+          },
+          index: { replaceWith: indexToUse++ },
+          source: { replaceWith: source },
+          keyword: { validIf: b => b.type == TYPE_BOOKMARK },
+          charset: { validIf: b => b.type == TYPE_BOOKMARK },
+          postData: { validIf: b => b.type == TYPE_BOOKMARK },
+          tags: { validIf: b => b.type == TYPE_BOOKMARK },
+          children: {
+            validIf: b => b.type == TYPE_FOLDER && Array.isArray(b.children),
+          },
+        };
+        if (fixupOrSkipInvalidEntries) {
+          insertInfo.guid.fixup = b =>
+            (b.guid = lazy.PlacesUtils.history.makeGuid());
+          insertInfo.dateAdded.fixup = insertInfo.lastModified.fixup = b =>
+            (b.lastModified = b.dateAdded = fallbackLastAdded);
+        }
+        try {
+          insertInfo = validateBookmarkObject(
+            "Bookmarks.jsm: insertTree",
+            info,
+            insertInfo
+          );
+        } catch (ex) {
+          if (fixupOrSkipInvalidEntries) {
+            indexToUse--;
+            continue;
+          } else {
+            throw ex;
+          }
+        }
+
+        if (shouldUseNullIndices) {
+          insertInfo.index = null;
+        }
+        // Store the URL if this is a bookmark, so we can ensure we create an
+        // entry in moz_places for it.
+        if (insertInfo.type == Bookmarks.TYPE_BOOKMARK) {
+          urlsThatMightNeedPlaces.push(insertInfo.url);
+        }
+
+        insertInfos.push(insertInfo);
+        // Process any children. We have to use info.children here rather than
+        // insertInfo.children because validateBookmarkObject doesn't copy over
+        // the children ref, as the default bookmark validators object doesn't
+        // know about children.
+        if (info.children) {
+          // start children of this item off at index 0.
+          let childrenLastAdded = appendInsertionInfoForInfoArray(
+            info.children,
+            0,
+            insertInfo.guid
+          );
+          if (childrenLastAdded > insertInfo.lastModified) {
+            insertInfo.lastModified = childrenLastAdded;
+          }
+          if (childrenLastAdded > lastAddedForParent) {
+            lastAddedForParent = childrenLastAdded;
+          }
+        }
+
+        // Ensure we track what time to update the parent to.
+        if (insertInfo.dateAdded > lastAddedForParent) {
+          lastAddedForParent = insertInfo.dateAdded;
+        }
+      }
+      return lastAddedForParent;
+    }
+
+    // We want to validate synchronously, but we can't know the index at which
+    // we're inserting into the parent. We just use NULL instead,
+    // and the SQL query with which we insert will update it as necessary.
+    let lastAddedForParent = appendInsertionInfoForInfoArray(
+      tree.children,
+      null,
+      tree.guid
+    );
+
+    // appendInsertionInfoForInfoArray will remove invalid items and may leave
+    // us with nothing to insert, if so, just return early.
+    if (!insertInfos.length) {
+      return [];
+    }
+
+    return (async function () {
+      let treeParent = await fetchBookmark({ guid: tree.guid });
+      if (!treeParent) {
+        throw new Error("The parent you specified doesn't exist.");
+      }
+
+      if (treeParent._parentId == lazy.PlacesUtils.tagsFolderId) {
+        throw new Error("Can't use insertTree to insert tags.");
+      }
+
+      await insertBookmarkTree(
+        insertInfos,
+        source,
+        treeParent,
+        urlsThatMightNeedPlaces,
+        lastAddedForParent
+      );
+
+      // Now update the indices of root items in the objects we return.
+      // These may be wrong if someone else modified the table between
+      // when we fetched the parent and inserted our items, but the actual
+      // inserts will have been correct, and we don't want to query the DB
+      // again if we don't have to. bug 1347230 covers improving this.
+      let rootIndex = treeParent._childCount;
+      for (let insertInfo of insertInfos) {
+        if (insertInfo.parentGuid == tree.guid) {
+          insertInfo.index += rootIndex++;
+        }
+      }
+
+      let itemDetailMap = await getBookmarkDetailMap(
+        insertInfos.map(info => info.guid)
+      );
+
+      let notifications = [];
+      for (let i = 0; i < insertInfos.length; i++) {
+        let item = insertInfos[i];
+        let itemDetail = itemDetailMap.get(item.guid);
+
+        // For sub-folders, we need to make sure their children have the correct parent ids.
+        let parentId;
+        if (item.parentGuid === treeParent.guid) {
+          // This is a direct child of the tree parent, so we can use the
+          // existing parent's id.
+          parentId = treeParent._id;
+        } else {
+          // This is a parent folder that's been updated, so we need to
+          // use the new item id.
+          parentId = itemDetail.parentId;
+        }
+
+        let url = "";
+        if (item.type == Bookmarks.TYPE_BOOKMARK) {
+          url = URL.isInstance(item.url) ? item.url.href : item.url;
+        }
+
+        notifications.push(
+          new PlacesBookmarkAddition({
+            id: itemDetail.id,
+            url,
+            itemType: item.type,
+            parentId,
+            index: item.index,
+            title: item.title,
+            dateAdded: item.dateAdded,
+            guid: item.guid,
+            parentGuid: item.parentGuid,
+            source: item.source,
+            isTagging: false,
+            tags: itemDetail.tags,
+            frecency: itemDetail.frecency,
+            hidden: itemDetail.hidden,
+            visitCount: itemDetail.visitCount,
+            lastVisitDate: itemDetail.lastVisitDate,
+            targetFolderGuid: itemDetail.targetFolderGuid,
+            targetFolderItemId: itemDetail.targetFolderItemId,
+            targetFolderTitle: itemDetail.targetFolderTitle,
+          })
+        );
+
+        try {
+          await handleBookmarkItemSpecialData(itemDetail.id, item);
+        } catch (ex) {
+          // This is not critical, regardless the bookmark has been created
+          // and we should continue notifying the next ones.
+          console.error(
+            "An error occured while handling special bookmark data:",
+            ex
+          );
+        }
+
+        // Remove non-enumerable properties.
+        delete item.source;
+
+        insertInfos[i] = Object.assign({}, item);
+      }
+
+      if (notifications.length) {
+        PlacesObservers.notifyListeners(notifications);
+      }
+
+      return insertInfos;
+    })();
+  },
+
+  /**
+   * Updates a bookmark-item.
+   *
+   * Only set the properties which should be changed (undefined properties
+   * won't be taken into account).
+   * Moreover, the item's type or dateAdded cannot be changed, since they are
+   * immutable after creation.  Trying to change them will reject.
+   *
+   * Note that any known properties that don't apply to the specific item type
+   * cause an exception.
+   *
+   * @param info
+   *        object representing a bookmark-item, as defined above.
+   *
+   * @return {Promise} resolved when the update is complete.
+   * @resolves to an object representing the updated bookmark.
+   * @rejects if it's not possible to update the given bookmark.
+   * @throws if the arguments are invalid.
+   */
+  update(info) {
+    // The info object is first validated here to ensure it's consistent, then
+    // it's compared to the existing item to remove any properties that don't
+    // need to be updated.
+    let updateInfo = validateBookmarkObject("Bookmarks.jsm: update", info, {
+      guid: { required: true },
+      index: {
+        requiredIf: b => b.hasOwnProperty("parentGuid"),
+        validIf: b => b.index >= 0 || b.index == this.DEFAULT_INDEX,
+      },
+      parentGuid: { validIf: b => b.parentGuid != this.rootGuid },
+      source: { defaultValue: this.SOURCES.DEFAULT },
+    });
+
+    // There should be at last one more property in addition to guid and source.
+    if (Object.keys(updateInfo).length < 3) {
+      throw new Error("Not enough properties to update");
+    }
+
+    return (async () => {
+      // Ensure the item exists.
+      let item = await fetchBookmark(updateInfo);
+      if (!item) {
+        throw new Error("No bookmarks found for the provided GUID");
+      }
+      if (updateInfo.hasOwnProperty("type") && updateInfo.type != item.type) {
+        throw new Error("The bookmark type cannot be changed");
+      }
+
+      // Remove any property that will stay the same.
+      removeSameValueProperties(updateInfo, item);
+      // Check if anything should still be updated.
+      if (Object.keys(updateInfo).length < 3) {
+        // Remove non-enumerable properties.
+        return Object.assign({}, item);
+      }
+      const now = new Date();
+      let lastModifiedDefault = now;
+      // In the case where `dateAdded` is specified, but `lastModified` is not,
+      // we only update `lastModified` if it is older than the new `dateAdded`.
+      if (!("lastModified" in updateInfo) && "dateAdded" in updateInfo) {
+        lastModifiedDefault = new Date(
+          Math.max(item.lastModified, updateInfo.dateAdded)
+        );
+      }
+      updateInfo = validateBookmarkObject("Bookmarks.jsm: update", updateInfo, {
+        url: { validIf: () => item.type == this.TYPE_BOOKMARK },
+        title: {
+          validIf: () =>
+            [this.TYPE_BOOKMARK, this.TYPE_FOLDER].includes(item.type),
+        },
+        lastModified: {
+          defaultValue: lastModifiedDefault,
+          validIf: b =>
+            b.lastModified >= now ||
+            b.lastModified >= (b.dateAdded || item.dateAdded),
+        },
+        dateAdded: { defaultValue: item.dateAdded },
+      });
+
+      return lazy.PlacesUtils.withConnectionWrapper(
+        "Bookmarks.jsm: update",
+        async db => {
+          let parent;
+          if (updateInfo.hasOwnProperty("parentGuid")) {
+            if (lazy.PlacesUtils.isRootItem(item.guid)) {
+              throw new Error("It's not possible to move Places root folders.");
+            }
+            if (item.type == this.TYPE_FOLDER) {
+              // Make sure we are not moving a folder into itself or one of its
+              // descendants.
+              let rows = await db.executeCached(
+                `WITH RECURSIVE
+               descendants(did) AS (
+                 VALUES(:id)
+                 UNION ALL
+                 SELECT id FROM moz_bookmarks
+                 JOIN descendants ON parent = did
+                 WHERE type = :type
+               )
+               SELECT guid FROM moz_bookmarks
+               WHERE id IN descendants
+              `,
+                { id: item._id, type: this.TYPE_FOLDER }
+              );
+              if (
+                rows
+                  .map(r => r.getResultByName("guid"))
+                  .includes(updateInfo.parentGuid)
+              ) {
+                throw new Error(
+                  "Cannot insert a folder into itself or one of its descendants"
+                );
+              }
+            }
+
+            parent = await fetchBookmark({ guid: updateInfo.parentGuid });
+            if (!parent) {
+              throw new Error("No bookmarks found for the provided parentGuid");
+            }
+          }
+
+          if (updateInfo.hasOwnProperty("index")) {
+            if (lazy.PlacesUtils.isRootItem(item.guid)) {
+              throw new Error("It's not possible to move Places root folders.");
+            }
+            // If at this point we don't have a parent yet, we are moving into
+            // the same container.  Thus we know it exists.
+            if (!parent) {
+              parent = await fetchBookmark({ guid: item.parentGuid });
+            }
+
+            if (
+              updateInfo.index >= parent._childCount ||
+              updateInfo.index == this.DEFAULT_INDEX
+            ) {
+              updateInfo.index = parent._childCount;
+
+              // Fix the index when moving within the same container.
+              if (parent.guid == item.parentGuid) {
+                updateInfo.index--;
+              }
+            }
+          }
+
+          let syncChangeDelta =
+            lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(
+              info.source
+            );
+
+          let updatedItem = await db.executeTransaction(async function () {
+            let updatedItem = await updateBookmark(
+              db,
+              updateInfo,
+              item,
+              item.index,
+              parent,
+              syncChangeDelta
+            );
+            if (parent) {
+              await setAncestorsLastModified(
+                db,
+                parent.guid,
+                updatedItem.lastModified,
+                syncChangeDelta
+              );
+            }
+            return updatedItem;
+          });
+
+          const notifications = [];
+
+          // For lastModified, we only care about the original input, since we
+          // should not notify implicit lastModified changes.
+          if (
+            (info.hasOwnProperty("lastModified") &&
+              updateInfo.hasOwnProperty("lastModified") &&
+              item.lastModified != updatedItem.lastModified) ||
+            (info.hasOwnProperty("dateAdded") &&
+              updateInfo.hasOwnProperty("dateAdded") &&
+              item.dateAdded != updatedItem.dateAdded)
+          ) {
+            let isTagging = updatedItem.parentGuid == Bookmarks.tagsGuid;
+            if (!isTagging) {
+              if (!parent) {
+                parent = await fetchBookmark({ guid: updatedItem.parentGuid });
+              }
+              isTagging = parent.parentGuid === Bookmarks.tagsGuid;
+            }
+
+            notifications.push(
+              new PlacesBookmarkTime({
+                id: updatedItem._id,
+                itemType: updatedItem.type,
+                url: updatedItem.url?.href,
+                guid: updatedItem.guid,
+                parentGuid: updatedItem.parentGuid,
+                dateAdded: updatedItem.dateAdded,
+                lastModified: updatedItem.lastModified,
+                source: updatedItem.source,
+                isTagging,
+              })
+            );
+          }
+
+          if (updateInfo.hasOwnProperty("title")) {
+            let isTagging = updatedItem.parentGuid == Bookmarks.tagsGuid;
+            if (!isTagging) {
+              if (!parent) {
+                parent = await fetchBookmark({ guid: updatedItem.parentGuid });
+              }
+              isTagging = parent.parentGuid === Bookmarks.tagsGuid;
+            }
+
+            notifications.push(
+              new PlacesBookmarkTitle({
+                id: updatedItem._id,
+                itemType: updatedItem.type,
+                url: updatedItem.url?.href,
+                guid: updatedItem.guid,
+                parentGuid: updatedItem.parentGuid,
+                title: updatedItem.title,
+                lastModified: updatedItem.lastModified,
+                source: updatedItem.source,
+                isTagging,
+              })
+            );
+
+            // If we're updating a tag, we must notify all the tagged bookmarks
+            // about the change.
+            if (isTagging) {
+              for (let entry of await fetchBookmarksByTags(
+                { tags: [updatedItem.title] },
+                { concurrent: true }
+              )) {
+                notifications.push(
+                  new PlacesBookmarkTags({
+                    id: entry._id,
+                    itemType: entry.type,
+                    url: entry.url,
+                    guid: entry.guid,
+                    parentGuid: entry.parentGuid,
+                    tags: entry._tags,
+                    lastModified: entry.lastModified,
+                    source: updatedItem.source,
+                    isTagging: false,
+                  })
+                );
+              }
+            }
+          }
+          if (updateInfo.hasOwnProperty("url")) {
+            await lazy.PlacesUtils.keywords.reassign(
+              item.url,
+              updatedItem.url,
+              updatedItem.source
+            );
+
+            let isTagging = updatedItem.parentGuid == Bookmarks.tagsGuid;
+            if (!isTagging) {
+              if (!parent) {
+                parent = await fetchBookmark({ guid: updatedItem.parentGuid });
+              }
+              isTagging = parent.parentGuid === Bookmarks.tagsGuid;
+            }
+
+            notifications.push(
+              new PlacesBookmarkUrl({
+                id: updatedItem._id,
+                itemType: updatedItem.type,
+                url: updatedItem.url.href,
+                guid: updatedItem.guid,
+                parentGuid: updatedItem.parentGuid,
+                source: updatedItem.source,
+                isTagging,
+                lastModified: updatedItem.lastModified,
+              })
+            );
+          }
+          // If the item was moved, notify bookmark-moved.
+          if (
+            item.parentGuid != updatedItem.parentGuid ||
+            item.index != updatedItem.index
+          ) {
+            let details = (await getBookmarkDetailMap([updatedItem.guid])).get(
+              updatedItem.guid
+            );
+            notifications.push(
+              new PlacesBookmarkMoved({
+                id: updatedItem._id,
+                itemType: updatedItem.type,
+                url: updatedItem.url && updatedItem.url.href,
+                guid: updatedItem.guid,
+                parentGuid: updatedItem.parentGuid,
+                source: updatedItem.source,
+                index: updatedItem.index,
+                oldParentGuid: item.parentGuid,
+                oldIndex: item.index,
+                isTagging:
+                  updatedItem.parentGuid === Bookmarks.tagsGuid ||
+                  parent.parentGuid === Bookmarks.tagsGuid,
+                title: updatedItem.title,
+                tags: details.tags,
+                frecency: details.frecency,
+                hidden: details.hidden,
+                visitCount: details.visitCount,
+                dateAdded: updatedItem.dateAdded ?? Date.now(),
+                lastVisitDate: details.lastVisitDate,
+              })
+            );
+          }
+
+          if (notifications.length) {
+            PlacesObservers.notifyListeners(notifications);
+          }
+
+          // Remove non-enumerable properties.
+          delete updatedItem.source;
+          return Object.assign({}, updatedItem);
+        }
+      );
+    })();
+  },
+
+  /**
+   * Moves multiple bookmark-items to a specific folder.
+   *
+   * If you are only updating/moving a single bookmark, use update() instead.
+   *
+   * @param {Array} guids
+   *        An array of GUIDs representing the bookmarks to move.
+   * @param {String} parentGuid
+   *        Optional, the parent GUID to move the bookmarks to.
+   * @param {Integer} index
+   *        The index to move the bookmarks to. If this is -1, the bookmarks
+   *        will be appended to the folder.
+   * @param {Integer} source
+   *        One of the Bookmarks.SOURCES.* options, representing the source of
+   *        this change.
+   *
+   * @return {Promise} resolved when the move is complete.
+   * @resolves to an array of objects representing the moved bookmarks.
+   * @rejects if it's not possible to move the given bookmark(s).
+   * @throws if the arguments are invalid.
+   */
+  moveToFolder(guids, parentGuid, index, source) {
+    if (!Array.isArray(guids) || guids.length < 1) {
+      throw new Error("guids should be an array of at least one item");
+    }
+    if (!guids.every(guid => lazy.PlacesUtils.isValidGuid(guid))) {
+      throw new Error("Expected only valid GUIDs to be passed.");
+    }
+    if (parentGuid && !lazy.PlacesUtils.isValidGuid(parentGuid)) {
+      throw new Error("parentGuid should be a valid GUID");
+    }
+    if (parentGuid == lazy.PlacesUtils.bookmarks.rootGuid) {
+      throw new Error("Cannot move bookmarks into root.");
+    }
+    if (typeof index != "number" || index < this.DEFAULT_INDEX) {
+      throw new Error(
+        `index should be a number greater than ${this.DEFAULT_INDEX}`
+      );
+    }
+
+    if (!source) {
+      source = this.SOURCES.DEFAULT;
+    }
+
+    return (async () => {
+      let updateInfos = [];
+      let syncChangeDelta =
+        lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(source);
+
+      await lazy.PlacesUtils.withConnectionWrapper(
+        "Bookmarks.jsm: moveToFolder",
+        async db => {
+          const lastModified = new Date();
+
+          let targetParentGuid = parentGuid || undefined;
+
+          for (let guid of guids) {
+            // Ensure the item exists.
+            let existingItem = await fetchBookmark({ guid }, { db });
+            if (!existingItem) {
+              throw new Error("No bookmarks found for the provided GUID");
+            }
+
+            if (parentGuid) {
+              // We're moving to a different folder.
+              if (existingItem.type == this.TYPE_FOLDER) {
+                // Make sure we are not moving a folder into itself or one of its
+                // descendants.
+                let rows = await db.executeCached(
+                  `WITH RECURSIVE
+                 descendants(did) AS (
+                   VALUES(:id)
+                   UNION ALL
+                   SELECT id FROM moz_bookmarks
+                   JOIN descendants ON parent = did
+                   WHERE type = :type
+                 )
+                 SELECT guid FROM moz_bookmarks
+                 WHERE id IN descendants
+                `,
+                  { id: existingItem._id, type: this.TYPE_FOLDER }
+                );
+                if (
+                  rows.map(r => r.getResultByName("guid")).includes(parentGuid)
+                ) {
+                  throw new Error(
+                    "Cannot insert a folder into itself or one of its descendants"
+                  );
+                }
+              }
+            } else if (!targetParentGuid) {
+              targetParentGuid = existingItem.parentGuid;
+            } else if (existingItem.parentGuid != targetParentGuid) {
+              throw new Error(
+                "All bookmarks should be in the same folder if no parent is specified"
+              );
+            }
+
+            updateInfos.push({ existingItem, currIndex: existingItem.index });
+          }
+
+          let newParent = await fetchBookmark(
+            { guid: targetParentGuid },
+            { db }
+          );
+
+          if (newParent._grandParentId == lazy.PlacesUtils.tagsFolderId) {
+            throw new Error("Can't move to a tags folder");
+          }
+
+          let newParentChildCount = newParent._childCount;
+
+          await db.executeTransaction(async () => {
+            // Now that we have all the existing items, we can do the actual updates.
+            for (let i = 0; i < updateInfos.length; i++) {
+              let info = updateInfos[i];
+              if (index != this.DEFAULT_INDEX) {
+                // If we're dropping on the same folder, then we may need to adjust
+                // the index to insert at the correct place.
+                if (info.existingItem.parentGuid == newParent.guid) {
+                  if (index > info.existingItem.index) {
+                    // If we're dragging down, we need to go one lower to insert at
+                    // the real point as moving the element changes the index of
+                    // everything below by 1.
+                    index--;
+                  } else if (index == info.existingItem.index) {
+                    // This isn't moving so we skip it, but copy the data so we have
+                    // an easy way for the notifications to check.
+                    info.updatedItem = { ...info.existingItem };
+                    continue;
+                  }
+                }
+              }
+
+              // Never let the index go higher than the max count of the folder.
+              if (index == this.DEFAULT_INDEX || index >= newParentChildCount) {
+                index = newParentChildCount;
+
+                // If this is moving within the same folder, then we need to drop the
+                // index by one to compensate for "removing" it, then re-inserting.
+                if (info.existingItem.parentGuid == newParent.guid) {
+                  index--;
+                }
+              }
+
+              info.updatedItem = await updateBookmark(
+                db,
+                { lastModified, index },
+                info.existingItem,
+                info.currIndex,
+                newParent,
+                syncChangeDelta
+              );
+              info.newParent = newParent;
+
+              // For items moving within the same folder, we have to keep track
+              // of their indexes. Otherwise we run the risk of not correctly
+              // updating the indexes of other items in the folder.
+              // This section simulates the database write in moveBookmark, which
+              // allows us to avoid re-reading the database.
+              if (info.existingItem.parentGuid == newParent.guid) {
+                let sign = index < info.currIndex ? 1 : -1;
+                for (let j = 0; j < updateInfos.length; j++) {
+                  if (j == i) {
+                    continue;
+                  }
+                  if (
+                    updateInfos[j].currIndex >=
+                      Math.min(info.currIndex, index) &&
+                    updateInfos[j].currIndex <= Math.max(info.currIndex, index)
+                  ) {
+                    updateInfos[j].currIndex += sign;
+                  }
+                }
+              }
+              info.currIndex = index;
+
+              // We only bump the parent count if we're moving from a different folder.
+              if (info.existingItem.parentGuid != newParent.guid) {
+                newParentChildCount++;
+              }
+              index++;
+            }
+
+            await setAncestorsLastModified(
+              db,
+              newParent.guid,
+              lastModified,
+              syncChangeDelta
+            );
+          });
+        }
+      );
+
+      const notifications = [];
+      let detailsMap = await getBookmarkDetailMap(
+        updateInfos.map(({ updatedItem }) => updatedItem.guid)
+      );
+      // Updates complete, time to notify everyone.
+      for (let { updatedItem, existingItem, newParent } of updateInfos) {
+        // If the item was moved, notify bookmark-moved.
+        // We use the updatedItem.index here, rather than currIndex, as the views
+        // need to know where we inserted the item as opposed to where it ended
+        // up.
+        if (
+          existingItem.parentGuid != updatedItem.parentGuid ||
+          existingItem.index != updatedItem.index
+        ) {
+          let details = detailsMap.get(updatedItem.guid);
+          notifications.push(
+            new PlacesBookmarkMoved({
+              id: updatedItem._id,
+              itemType: updatedItem.type,
+              url: existingItem.url,
+              guid: updatedItem.guid,
+              parentGuid: updatedItem.parentGuid,
+              source,
+              index: updatedItem.index,
+              oldParentGuid: existingItem.parentGuid,
+              oldIndex: existingItem.index,
+              isTagging:
+                updatedItem.parentGuid === Bookmarks.tagsGuid ||
+                newParent.parentGuid === Bookmarks.tagsGuid,
+              title: updatedItem.title,
+              tags: details.tags,
+              frecency: details.frecency,
+              hidden: details.hidden,
+              visitCount: details.visitCount,
+              dateAdded: updatedItem.dateAdded,
+              lastVisitDate: details.lastVisitDate,
+            })
+          );
+        }
+        // Remove non-enumerable properties.
+        delete updatedItem.source;
+      }
+
+      if (notifications.length) {
+        PlacesObservers.notifyListeners(notifications);
+      }
+
+      return updateInfos.map(updateInfo =>
+        Object.assign({}, updateInfo.updatedItem)
+      );
+    })();
+  },
+
+  /**
+   * Removes one or more bookmark-items.
+   *
+   * @param guidOrInfo This may be:
+   *        - The globally unique identifier of the item to remove
+   *        - an object representing the item, as defined above
+   *        - an array of objects representing the items to be removed
+   * @param {Object} [options={}]
+   *        Additional options that can be passed to the function.
+   *        Currently supports the following properties:
+   *         - preventRemovalOfNonEmptyFolders: Causes an exception to be
+   *           thrown when attempting to remove a folder that is not empty.
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise}
+   * @resolves when the removal is complete
+   * @rejects if the provided guid doesn't match any existing bookmark.
+   * @throws if the arguments are invalid.
+   */
+  remove(guidOrInfo, options = {}) {
+    let infos = guidOrInfo;
+    if (!infos) {
+      throw new Error("Input should be a valid object");
+    }
+    if (!Array.isArray(guidOrInfo)) {
+      if (typeof guidOrInfo != "object") {
+        infos = [{ guid: guidOrInfo }];
+      } else {
+        infos = [guidOrInfo];
+      }
+    }
+
+    if (!("source" in options)) {
+      options.source = Bookmarks.SOURCES.DEFAULT;
+    }
+
+    let removeInfos = [];
+    for (let info of infos) {
+      // Disallow removing the root folders.
+      if (
+        [
+          Bookmarks.rootGuid,
+          Bookmarks.menuGuid,
+          Bookmarks.toolbarGuid,
+          Bookmarks.unfiledGuid,
+          Bookmarks.tagsGuid,
+          Bookmarks.mobileGuid,
+        ].includes(info.guid)
+      ) {
+        throw new Error("It's not possible to remove Places root folders.");
+      }
+
+      // Even if we ignore any other unneeded property, we still validate any
+      // known property to reduce likelihood of hidden bugs.
+      let removeInfo = validateBookmarkObject("Bookmarks.jsm: remove", info);
+      removeInfos.push(removeInfo);
+    }
+
+    return (async function () {
+      let removeItems = [];
+      for (let info of removeInfos) {
+        // We must be able to remove a bookmark even if it has an invalid url.
+        // In that case the item won't have a url property.
+        let item = await fetchBookmark(info, { ignoreInvalidURLs: true });
+        if (!item) {
+          throw new Error("No bookmarks found for the provided GUID.");
+        }
+
+        removeItems.push(item);
+      }
+
+      await removeBookmarks(removeItems, options);
+
+      // Notify bookmark-removed to listeners.
+      let notifications = [];
+
+      for (let item of removeItems) {
+        let isUntagging = item._grandParentId == lazy.PlacesUtils.tagsFolderId;
+        let url = "";
+        if (item.type == Bookmarks.TYPE_BOOKMARK) {
+          url = item.hasOwnProperty("url") ? item.url.href : null;
+        }
+
+        notifications.push(
+          new PlacesBookmarkRemoved({
+            id: item._id,
+            url,
+            title: item.title,
+            itemType: item.type,
+            parentId: item._parentId,
+            index: item.index,
+            guid: item.guid,
+            parentGuid: item.parentGuid,
+            source: options.source,
+            isTagging: isUntagging,
+            isDescendantRemoval: false,
+          })
+        );
+
+        if (isUntagging) {
+          for (let entry of await fetchBookmarksByURL(item, {
+            concurrent: true,
+          })) {
+            notifications.push(
+              new PlacesBookmarkTags({
+                id: entry._id,
+                itemType: entry.type,
+                url,
+                guid: entry.guid,
+                parentGuid: entry.parentGuid,
+                tags: entry._tags,
+                lastModified: entry.lastModified,
+                source: options.source,
+                isTagging: false,
+              })
+            );
+          }
+        }
+      }
+
+      PlacesObservers.notifyListeners(notifications);
+    })();
+  },
+
+  /**
+   * Removes ALL bookmarks, resetting the bookmarks storage to an empty tree.
+   *
+   * Note that roots are preserved, only their children will be removed.
+   *
+   * @param {Object} [options={}]
+   *        Additional options. Currently supports the following properties:
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise} resolved when the removal is complete.
+   * @resolves once the removal is complete.
+   */
+  eraseEverything(options = {}) {
+    if (!options.source) {
+      options.source = Bookmarks.SOURCES.DEFAULT;
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "Bookmarks.jsm: eraseEverything",
+      async function (db) {
+        let urls;
+        await db.executeTransaction(async function () {
+          urls = await removeFoldersContents(
+            db,
+            Bookmarks.userContentRoots,
+            options
+          );
+          const time = lazy.PlacesUtils.toPRTime(new Date());
+          const syncChangeDelta =
+            lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(
+              options.source
+            );
+          for (let folderGuid of Bookmarks.userContentRoots) {
+            await db.executeCached(
+              `UPDATE moz_bookmarks SET lastModified = :time,
+                                        syncChangeCounter = syncChangeCounter + :syncChangeDelta
+               WHERE id IN (SELECT id FROM moz_bookmarks WHERE guid = :folderGuid )
+              `,
+              { folderGuid, time, syncChangeDelta }
+            );
+          }
+
+          await lazy.PlacesSyncUtils.bookmarks.resetSyncMetadata(
+            db,
+            options.source
+          );
+        });
+
+        if (urls?.length) {
+          await lazy.PlacesUtils.keywords.eraseEverything();
+        }
+      }
+    );
+  },
+
+  /**
+   * Returns a list of recently bookmarked items.
+   * Only includes actual bookmarks. Excludes folders, separators and queries.
+   *
+   * @param {integer} numberOfItems
+   *        The maximum number of bookmark items to return.
+   *
+   * @return {Promise} resolved when the listing is complete.
+   * @resolves to an array of recent bookmark-items.
+   * @rejects if an error happens while querying.
+   */
+  getRecent(numberOfItems) {
+    if (numberOfItems === undefined) {
+      throw new Error("numberOfItems argument is required");
+    }
+    if (typeof numberOfItems !== "number" || numberOfItems % 1 !== 0) {
+      throw new Error("numberOfItems argument must be an integer");
+    }
+    if (numberOfItems <= 0) {
+      throw new Error("numberOfItems argument must be greater than zero");
+    }
+
+    return fetchRecentBookmarks(numberOfItems);
+  },
+
+  /**
+   * Fetches information about a bookmark-item.
+   *
+   * REMARK: any successful call to this method resolves to a single
+   *         bookmark-item (or null), even when multiple bookmarks may exist
+   *         (e.g. fetching by url).  If you wish to retrieve all of the
+   *         bookmarks for a given match, use the callback instead.
+   *
+   * Input can be either a guid or an object with one, and only one, of these
+   * filtering properties set:
+   *  - guid
+   *      retrieves the item with the specified guid.
+   *  - parentGuid and index
+   *      retrieves the item by its position.
+   *  - url
+   *      retrieves the most recent bookmark having the given URL.
+   *      To retrieve ALL of the bookmarks for that URL, you must pass in an
+   *      onResult callback, that will be invoked once for each found bookmark.
+   *  - guidPrefix
+   *      retrieves the most recent item with the specified guid prefix.
+   *      To retrieve ALL of the bookmarks for that guid prefix, you must pass
+   *      in an onResult callback, that will be invoked once for each bookmark.
+   *  - tags
+   *      Retrieves the most recent item with all the specified tags.
+   *      The tags are matched in a case-insensitive way.
+   *      To retrieve ALL of the bookmarks having these tags, pass in an
+   *      onResult callback, that will be invoked once for each bookmark.
+   *      Note, there can be multiple bookmarks for the same url, if you need
+   *      unique tagged urls you can filter duplicates by accumulating in a Set.
+   *
+   * @param guidOrInfo
+   *        The globally unique identifier of the item to fetch, or an
+   *        object representing it, as defined above.
+   * @param onResult [optional]
+   *        Callback invoked for each found bookmark.
+   * @param options [optional]
+   *        an optional object whose properties describe options for the fetch:
+   *         - concurrent: fetches concurrently to any writes, returning results
+   *                       faster. On the negative side, it may return stale
+   *                       information missing the currently ongoing write.
+   *         - includePath: additionally fetches the path for the bookmarks.
+   *                        This is a potentially expensive operation.  When
+   *                        set to true, the path property is set on results
+   *                        containing an array of {title, guid} objects
+   *                        ordered from root to leaf.
+   *         - includeItemIds:
+   *             include .itemId and .parentId in the results.
+   *             ALWAYS USE THE GUIDs instead of these, unless it's _really_
+   *             necessary to get them, e.g. when sending Places notifications.
+   *
+   * @return {Promise} resolved when the fetch is complete.
+   * @resolves to an object representing the found item, as described above, or
+   *           an array of such objects.  if no item is found, the returned
+   *           promise is resolved to null.
+   * @rejects if an error happens while fetching.
+   * @throws if the arguments are invalid.
+   *
+   * @note Any unknown property in the info object is ignored.  Known properties
+   *       may be overwritten.
+   */
+  async fetch(guidOrInfo, onResult = null, options = {}) {
+    if (onResult && typeof onResult != "function") {
+      throw new Error("onResult callback must be a valid function");
+    }
+    let info = guidOrInfo;
+    if (!info) {
+      throw new Error("Input should be a valid object");
+    }
+    if (typeof info != "object") {
+      info = { guid: guidOrInfo };
+    } else if (Object.keys(info).length == 1) {
+      // Just a faster code path.
+      if (
+        !["url", "guid", "parentGuid", "index", "guidPrefix", "tags"].includes(
+          Object.keys(info)[0]
+        )
+      ) {
+        throw new Error(`Unexpected number of conditions provided: 0`);
+      }
+    } else {
+      // Only one condition at a time can be provided.
+      let conditionsCount = [
+        v => v.hasOwnProperty("guid"),
+        v => v.hasOwnProperty("parentGuid") && v.hasOwnProperty("index"),
+        v => v.hasOwnProperty("url"),
+        v => v.hasOwnProperty("guidPrefix"),
+        v => v.hasOwnProperty("tags"),
+      ].reduce((old, fn) => (old + fn(info)) | 0, 0);
+      if (conditionsCount != 1) {
+        throw new Error(
+          `Unexpected number of conditions provided: ${conditionsCount}`
+        );
+      }
+    }
+
+    // Create a new options object with just the support properties, because
+    // we may augment it and hand it down to other methods.
+    options = {
+      concurrent: !!options.concurrent,
+      includePath: !!options.includePath,
+      includeItemIds: !!options.includeItemIds,
+    };
+
+    let behavior = {};
+    if (info.hasOwnProperty("parentGuid") || info.hasOwnProperty("index")) {
+      behavior = {
+        parentGuid: { requiredIf: b => b.hasOwnProperty("index") },
+        index: {
+          validIf: b =>
+            (typeof b.index == "number" && b.index >= 0) ||
+            b.index == this.DEFAULT_INDEX,
+        },
+      };
+    }
+
+    // Even if we ignore any other unneeded property, we still validate any
+    // known property to reduce likelihood of hidden bugs.
+    let fetchInfo = validateBookmarkObject(
+      "Bookmarks.jsm: fetch",
+      info,
+      behavior
+    );
+
+    let results;
+    if (fetchInfo.hasOwnProperty("url")) {
+      results = await fetchBookmarksByURL(fetchInfo, options);
+    } else if (fetchInfo.hasOwnProperty("guid")) {
+      results = await fetchBookmark(fetchInfo, options);
+    } else if (fetchInfo.hasOwnProperty("parentGuid")) {
+      if (fetchInfo.hasOwnProperty("index")) {
+        results = await fetchBookmarkByPosition(fetchInfo, options);
+      } else {
+        results = await fetchBookmarksByParentGUID(fetchInfo, options);
+      }
+    } else if (fetchInfo.hasOwnProperty("guidPrefix")) {
+      results = await fetchBookmarksByGUIDPrefix(fetchInfo, options);
+    } else if (fetchInfo.hasOwnProperty("tags")) {
+      results = await fetchBookmarksByTags(fetchInfo, options);
+    }
+
+    if (!results) {
+      return null;
+    }
+
+    if (!Array.isArray(results)) {
+      results = [results];
+    }
+    // Remove non-enumerable properties.
+    results = results.map(r => {
+      if (r.type == this.TYPE_FOLDER) {
+        r.childCount = r._childCount;
+      }
+      if (options.includeItemIds) {
+        r.itemId = r._id;
+        r.parentId = r._parentId;
+      }
+      return Object.assign({}, r);
+    });
+
+    if (options.includePath) {
+      for (let result of results) {
+        let folderPath = await retrieveFullBookmarkPath(result.parentGuid);
+        if (folderPath) {
+          result.path = folderPath;
+        }
+      }
+    }
+
+    // Ideally this should handle an incremental behavior and thus be invoked
+    // while we fetch.  Though, the likelihood of 2 or more bookmarks for the
+    // same match is very low, so it's not worth the added code complication.
+    if (onResult) {
+      for (let result of results) {
+        try {
+          onResult(result);
+        } catch (ex) {
+          console.error(ex);
+        }
+      }
+    }
+
+    return results[0];
+  },
+
+  /**
+   * Retrieves an object representation of a bookmark-item, along with all of
+   * its descendants, if any.
+   *
+   * Each node in the tree is an object that extends the item representation
+   * described above with some additional properties:
+   *
+   *  - [deprecated] itemId (number)
+   *      the item's id.  Defined only if aOptions.includeItemIds is set.
+   *  - [deprecated] parentId (number)
+   *      the item's parent id.  Defined only if aOptions.includeItemIds is set.
+   *  - annos (array)
+   *      the item's annotations.  This is not set if there are no annotations
+   *      set for the item.
+   *
+   * The root object of the tree also has the following properties set:
+   *  - itemsCount (number, not enumerable)
+   *      the number of items, including the root item itself, which are
+   *      represented in the resolved object.
+   *
+   * Bookmarked URLs may also have the following properties:
+   *  - tags (string)
+   *      csv string of the bookmark's tags, if any.
+   *  - charset (string)
+   *      the last known charset of the bookmark, if any.
+   *  - iconurl (URL)
+   *      the bookmark's favicon URL, if any.
+   *
+   * Folders may also have the following properties:
+   *  - children (array)
+   *      the folder's children information, each of them having the same set of
+   *      properties as above.
+   *
+   * @param [optional] guid
+   *        the topmost item to be queried.  If it's not passed, the Places
+   *        root folder is queried: that is, you get a representation of the
+   *        entire bookmarks hierarchy.
+   * @param [optional] options
+   *        Options for customizing the query behavior, in the form of an
+   *        object with any of the following properties:
+   *         - excludeItemsCallback: a function for excluding items, along with
+   *           their descendants.  Given an item object (that has everything set
+   *           apart its potential children data), it should return true if the
+   *           item should be excluded.  Once an item is excluded, the function
+   *           isn't called for any of its descendants.  This isn't called for
+   *           the root item.
+   *           WARNING: since the function may be called for each item, using
+   *           this option can slow down the process significantly if the
+   *           callback does anything that's not relatively trivial.  It is
+   *           highly recommended to avoid any synchronous I/O or DB queries.
+   *         - includeItemIds: opt-in to include the deprecated id property.
+   *           Use it if you must. It'll be removed once the switch to guids is
+   *           complete.
+   *
+   * @return {Promise} resolved when the fetch is complete.
+   * @resolves to an object that represents either a single item or a
+   *           bookmarks tree.  if guid points to a non-existent item, the
+   *           returned promise is resolved to null.
+   * @rejects if an error happens while fetching.
+   * @throws if the arguments are invalid.
+   */
+  // TODO must implement these methods yet:
+  // PlacesUtils.promiseBookmarksTree()
+  fetchTree(guid = "", options = {}) {
+    throw new Error("Not yet implemented");
+  },
+
+  /**
+   * Fetch all the existing tags, sorted alphabetically.
+   * @return {Promise} resolves to an array of objects representing tags, when
+   *         fetching is complete.
+   *         Each object looks like {
+   *           name: the name of the tag,
+   *           count: number of bookmarks with this tag
+   *         }
+   */
+  async fetchTags() {
+    // TODO: Once the tagging API is implemented in Bookmarks.jsm, we can cache
+    // the list of tags, instead of querying every time.
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `
+      SELECT b.title AS name, count(*) AS count
+      FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON b.parent = p.id
+      JOIN moz_bookmarks c ON c.parent = b.id
+      WHERE p.guid = :tagsGuid
+      GROUP BY name
+      ORDER BY name COLLATE nocase ASC
+    `,
+      { tagsGuid: this.tagsGuid }
+    );
+    return rows.map(r => ({
+      name: r.getResultByName("name"),
+      count: r.getResultByName("count"),
+    }));
+  },
+
+  /**
+   * Reorders contents of a folder based on a provided array of GUIDs.
+   *
+   * @param parentGuid
+   *        The globally unique identifier of the folder whose contents should
+   *        be reordered.
+   * @param orderedChildrenGuids
+   *        Ordered array of the children's GUIDs.  If this list contains
+   *        non-existing entries they will be ignored.  If the list is
+   *        incomplete, and the current child list is already in order with
+   *        respect to orderedChildrenGuids, no change is made. Otherwise, the
+   *        new items are appended but maintain their current order relative to
+   *        eachother.
+   * @param {Object} [options={}]
+   *        Additional options. Currently supports the following properties:
+   *         - lastModified: The last modified time to use for the folder and
+               reordered children. Defaults to the current time.
+   *         - source: The change source, forwarded to all bookmark observers.
+   *           Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *
+   * @return {Promise} resolved when reordering is complete.
+   * @rejects if an error happens while reordering.
+   * @throws if the arguments are invalid.
+   */
+  reorder(parentGuid, orderedChildrenGuids, options = {}) {
+    let info = { guid: parentGuid };
+    info = validateBookmarkObject("Bookmarks.jsm: reorder", info, {
+      guid: { required: true },
+    });
+
+    if (!Array.isArray(orderedChildrenGuids) || !orderedChildrenGuids.length) {
+      throw new Error("Must provide a sorted array of children GUIDs.");
+    }
+    try {
+      orderedChildrenGuids.forEach(lazy.PlacesUtils.BOOKMARK_VALIDATORS.guid);
+    } catch (ex) {
+      throw new Error("Invalid GUID found in the sorted children array.");
+    }
+
+    options.source =
+      "source" in options
+        ? lazy.PlacesUtils.BOOKMARK_VALIDATORS.source(options.source)
+        : Bookmarks.SOURCES.DEFAULT;
+    options.lastModified =
+      "lastModified" in options
+        ? lazy.PlacesUtils.BOOKMARK_VALIDATORS.lastModified(
+            options.lastModified
+          )
+        : new Date();
+
+    return (async () => {
+      let parent = await fetchBookmark(info);
+      if (!parent || parent.type != this.TYPE_FOLDER) {
+        throw new Error("No folder found for the provided GUID.");
+      }
+      if (parent._childCount == 0) {
+        return;
+      }
+
+      let sortedChildren = await reorderChildren(
+        parent,
+        orderedChildrenGuids,
+        options
+      );
+
+      const notifications = [];
+      let detailsMap = await getBookmarkDetailMap(
+        sortedChildren.map(c => c.guid)
+      );
+      for (let child of sortedChildren) {
+        let details = detailsMap.get(child.guid);
+        notifications.push(
+          new PlacesBookmarkMoved({
+            id: child._id,
+            itemType: child.type,
+            url: child.url?.href,
+            guid: child.guid,
+            parentGuid: child.parentGuid,
+            source: options.source,
+            index: child.index,
+            oldParentGuid: child.parentGuid,
+            oldIndex: child._oldIndex,
+            isTagging:
+              child.parentGuid === Bookmarks.tagsGuid ||
+              parent.parentGuid === Bookmarks.tagsGuid,
+            title: child.title,
+            tags: details.tags,
+            frecency: details.frecency,
+            hidden: details.hidden,
+            visitCount: details.visitCount,
+            dateAdded: child.dateAdded,
+            lastVisitDate: details.lastVisitDate,
+          })
+        );
+      }
+      if (notifications.length) {
+        PlacesObservers.notifyListeners(notifications);
+      }
+    })();
+  },
+
+  /**
+   * Searches a list of bookmark-items by a search term, url or title.
+   *
+   * IMPORTANT:
+   * This is intended as an interim API for the web-extensions implementation.
+   * It will be removed as soon as we have a new querying API.
+   *
+   * Note also that this used to exclude separators but no longer does so.
+   *
+   * If you just want to search bookmarks by URL, use .fetch() instead.
+   *
+   * @param query
+   *        Either a string to use as search term, or an object
+   *        containing any of these keys: query, title or url with the
+   *        corresponding string to match as value.
+   *        The url property can be either a string or an nsIURI.
+   *
+   * @return {Promise} resolved when the search is complete.
+   * @resolves to an array of found bookmark-items.
+   * @rejects if an error happens while searching.
+   * @throws if the arguments are invalid.
+   *
+   * @note Any unknown property in the query object is ignored.
+   *       Known properties may be overwritten.
+   */
+  search(query) {
+    if (!query) {
+      throw new Error("Query object is required");
+    }
+    if (typeof query === "string") {
+      query = { query };
+    }
+    if (typeof query !== "object") {
+      throw new Error("Query must be an object or a string");
+    }
+    if (query.query && typeof query.query !== "string") {
+      throw new Error("Query option must be a string");
+    }
+    if (query.title && typeof query.title !== "string") {
+      throw new Error("Title option must be a string");
+    }
+
+    if (query.url) {
+      if (typeof query.url === "string" || URL.isInstance(query.url)) {
+        query.url = new URL(query.url).href;
+      } else if (query.url instanceof Ci.nsIURI) {
+        query.url = query.url.spec;
+      } else {
+        throw new Error("Url option must be a string or a URL object");
+      }
+    }
+
+    return queryBookmarks(query);
+  },
+});
+
+// Globals.
+
+// Update implementation.
+
+/**
+ * Updates a single bookmark in the database. This should be called from within
+ * a transaction.
+ *
+ * @param {Object} db The pre-existing database connection.
+ * @param {Object} info A bookmark-item structure with new properties.
+ * @param {Object} item A bookmark-item structure representing the existing bookmark.
+ * @param {Integer} oldIndex The index of the item in the old parent.
+ * @param {Object} newParent The new parent folder (note: this may be the same as)
+ *                           the existing folder.
+ * @param {Integer} syncChangeDelta The change delta to be applied.
+ */
+async function updateBookmark(
+  db,
+  info,
+  item,
+  oldIndex,
+  newParent,
+  syncChangeDelta
+) {
+  let tuples = new Map();
+  tuples.set("lastModified", {
+    value: lazy.PlacesUtils.toPRTime(info.lastModified),
+  });
+  if (info.hasOwnProperty("title")) {
+    tuples.set("title", {
+      value: info.title,
+      fragment: `title = NULLIF(:title, '')`,
+    });
+  }
+  if (info.hasOwnProperty("dateAdded")) {
+    tuples.set("dateAdded", {
+      value: lazy.PlacesUtils.toPRTime(info.dateAdded),
+    });
+  }
+
+  if (info.hasOwnProperty("url")) {
+    // Ensure a page exists in moz_places for this URL.
+    await lazy.PlacesUtils.maybeInsertPlace(db, info.url);
+    // Update tuples for the update query.
+    tuples.set("url", {
+      value: info.url.href,
+      fragment:
+        "fk = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url)",
+    });
+  }
+
+  let newIndex = info.hasOwnProperty("index") ? info.index : item.index;
+  if (newParent) {
+    // For simplicity, update the index regardless.
+    tuples.set("position", { value: newIndex });
+
+    // For moving within the same parent, we've already updated the indexes.
+    if (newParent.guid == item.parentGuid) {
+      // Moving inside the original container.
+      // When moving "up", add 1 to each index in the interval.
+      // Otherwise when moving down, we subtract 1.
+      // Only the parent needs a sync change, which is handled in
+      // `setAncestorsLastModified`.
+      await db.executeCached(
+        `UPDATE moz_bookmarks
+           SET position = CASE WHEN :newIndex < :currIndex
+             THEN position + 1
+             ELSE position - 1
+           END
+           WHERE parent = :newParentId
+             AND position BETWEEN :lowIndex AND :highIndex
+          `,
+        {
+          newIndex,
+          currIndex: oldIndex,
+          newParentId: newParent._id,
+          lowIndex: Math.min(oldIndex, newIndex),
+          highIndex: Math.max(oldIndex, newIndex),
+        }
+      );
+    } else {
+      // Moving across different containers. In this case, both parents and
+      // the child need sync changes. `setAncestorsLastModified`, below and in
+      // `update` and `moveToFolder`, handles the parents. The `needsSyncChange`
+      // check below handles the child.
+      tuples.set("parent", { value: newParent._id });
+      await db.executeCached(
+        `UPDATE moz_bookmarks SET position = position - 1
+         WHERE parent = :oldParentId
+           AND position >= :oldIndex
+        `,
+        { oldParentId: item._parentId, oldIndex }
+      );
+      await db.executeCached(
+        `UPDATE moz_bookmarks SET position = position + 1
+         WHERE parent = :newParentId
+           AND position >= :newIndex
+        `,
+        { newParentId: newParent._id, newIndex }
+      );
+
+      await setAncestorsLastModified(
+        db,
+        item.parentGuid,
+        info.lastModified,
+        syncChangeDelta
+      );
+    }
+  }
+
+  if (syncChangeDelta) {
+    // Sync stores child indices in the parent's record, so we only bump the
+    // item's counter if we're updating at least one more property in
+    // addition to the index, last modified time, and dateAdded.
+    let sizeThreshold = 1;
+    if (newIndex != oldIndex) {
+      ++sizeThreshold;
+    }
+    if (tuples.has("dateAdded")) {
+      ++sizeThreshold;
+    }
+    let needsSyncChange = tuples.size > sizeThreshold;
+    if (needsSyncChange) {
+      tuples.set("syncChangeDelta", {
+        value: syncChangeDelta,
+        fragment: "syncChangeCounter = syncChangeCounter + :syncChangeDelta",
+      });
+    }
+  }
+
+  let isTagging = item._grandParentId == lazy.PlacesUtils.tagsFolderId;
+  if (isTagging) {
+    // If we're updating a tag entry, bump the sync change counter for
+    // bookmarks with the tagged URL.
+    await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+      db,
+      item.url,
+      syncChangeDelta
+    );
+    if (info.hasOwnProperty("url")) {
+      // Changing the URL of a tag entry is equivalent to untagging the
+      // old URL and tagging the new one, so we bump the change counter
+      // for the new URL here.
+      await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+        db,
+        info.url,
+        syncChangeDelta
+      );
+    }
+  }
+
+  let isChangingTagFolder = item._parentId == lazy.PlacesUtils.tagsFolderId;
+  if (isChangingTagFolder && syncChangeDelta) {
+    // If we're updating a tag folder (for example, changing a tag's title),
+    // bump the change counter for all tagged bookmarks.
+    await db.executeCached(
+      `
+      UPDATE moz_bookmarks SET
+        syncChangeCounter = syncChangeCounter + :syncChangeDelta
+      WHERE type = :type AND
+            fk = (SELECT fk FROM moz_bookmarks WHERE parent = :parent)
+      `,
+      { syncChangeDelta, type: Bookmarks.TYPE_BOOKMARK, parent: item._id }
+    );
+  }
+
+  await db.executeCached(
+    `UPDATE moz_bookmarks
+     SET ${Array.from(tuples.keys())
+       .map(v => tuples.get(v).fragment || `${v} = :${v}`)
+       .join(", ")}
+     WHERE guid = :guid
+    `,
+    Object.assign(
+      { guid: item.guid },
+      [...tuples.entries()].reduce((p, c) => {
+        p[c[0]] = c[1].value;
+        return p;
+      }, {})
+    )
+  );
+
+  if (newParent) {
+    if (newParent.guid == item.parentGuid) {
+      // Mark all affected separators as changed
+      // Also bumps the change counter if the item itself is a separator
+      const startIndex = Math.min(newIndex, oldIndex);
+      await adjustSeparatorsSyncCounter(
+        db,
+        newParent._id,
+        startIndex,
+        syncChangeDelta
+      );
+    } else {
+      // Mark all affected separators as changed
+      await adjustSeparatorsSyncCounter(
+        db,
+        item._parentId,
+        oldIndex,
+        syncChangeDelta
+      );
+      await adjustSeparatorsSyncCounter(
+        db,
+        newParent._id,
+        newIndex,
+        syncChangeDelta
+      );
+    }
+  }
+
+  // If the parent changed, update related non-enumerable properties.
+  let additionalParentInfo = {};
+  if (newParent) {
+    additionalParentInfo.parentGuid = newParent.guid;
+    Object.defineProperty(additionalParentInfo, "_parentId", {
+      value: newParent._id,
+      enumerable: false,
+    });
+    Object.defineProperty(additionalParentInfo, "_grandParentId", {
+      value: newParent._parentId,
+      enumerable: false,
+    });
+  }
+
+  return mergeIntoNewObject(item, info, additionalParentInfo);
+}
+
+// Insert implementation.
+
+function insertBookmark(item, parent) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: insertBookmark",
+    async function (db) {
+      // If a guid was not provided, generate one, so we won't need to fetch the
+      // bookmark just after having created it.
+      let hasExistingGuid = item.hasOwnProperty("guid");
+      if (!hasExistingGuid) {
+        item.guid = lazy.PlacesUtils.history.makeGuid();
+      }
+
+      let isTagging = parent._parentId == lazy.PlacesUtils.tagsFolderId;
+
+      await db.executeTransaction(async function transaction() {
+        if (item.type == Bookmarks.TYPE_BOOKMARK) {
+          // Ensure a page exists in moz_places for this URL.
+          // The IGNORE conflict can trigger on `guid`.
+          await lazy.PlacesUtils.maybeInsertPlace(db, item.url);
+        }
+
+        // Adjust indices.
+        await db.executeCached(
+          `UPDATE moz_bookmarks SET position = position + 1
+         WHERE parent = :parent
+         AND position >= :index
+        `,
+          { parent: parent._id, index: item.index }
+        );
+
+        let syncChangeDelta =
+          lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(item.source);
+        let syncStatus =
+          lazy.PlacesSyncUtils.bookmarks.determineInitialSyncStatus(
+            item.source
+          );
+
+        // Insert the bookmark into the database.
+        await db.executeCached(
+          `INSERT INTO moz_bookmarks (fk, type, parent, position, title,
+                                    dateAdded, lastModified, guid,
+                                    syncChangeCounter, syncStatus)
+         VALUES (CASE WHEN :url ISNULL THEN NULL ELSE (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url) END,
+                 :type, :parent, :index, NULLIF(:title, ''), :date_added,
+                 :last_modified, :guid, :syncChangeCounter, :syncStatus)
+        `,
+          {
+            url: item.hasOwnProperty("url") ? item.url.href : null,
+            type: item.type,
+            parent: parent._id,
+            index: item.index,
+            title: item.title,
+            date_added: lazy.PlacesUtils.toPRTime(item.dateAdded),
+            last_modified: lazy.PlacesUtils.toPRTime(item.lastModified),
+            guid: item.guid,
+            syncChangeCounter: syncChangeDelta,
+            syncStatus,
+          }
+        );
+
+        // Mark all affected separators as changed
+        await adjustSeparatorsSyncCounter(
+          db,
+          parent._id,
+          item.index + 1,
+          syncChangeDelta
+        );
+
+        if (hasExistingGuid) {
+          // Remove stale tombstones if we're reinserting an item.
+          await db.executeCached(
+            `DELETE FROM moz_bookmarks_deleted WHERE guid = :guid`,
+            { guid: item.guid }
+          );
+        }
+
+        if (isTagging) {
+          // New tag entry; bump the change counter for bookmarks with the
+          // tagged URL.
+          await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+            db,
+            item.url,
+            syncChangeDelta
+          );
+        }
+
+        await setAncestorsLastModified(
+          db,
+          item.parentGuid,
+          item.dateAdded,
+          syncChangeDelta
+        );
+      });
+
+      return item;
+    }
+  );
+}
+
+function insertBookmarkTree(items, source, parent, urls, lastAddedForParent) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: insertBookmarkTree",
+    async function (db) {
+      await db.executeTransaction(async function transaction() {
+        await lazy.PlacesUtils.maybeInsertManyPlaces(db, urls);
+
+        let syncChangeDelta =
+          lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(source);
+        let syncStatus =
+          lazy.PlacesSyncUtils.bookmarks.determineInitialSyncStatus(source);
+
+        let rootId = parent._id;
+
+        items = items.map(item => ({
+          url: item.url && item.url.href,
+          type: item.type,
+          parentGuid: item.parentGuid,
+          index: item.index,
+          title: item.title,
+          date_added: lazy.PlacesUtils.toPRTime(item.dateAdded),
+          last_modified: lazy.PlacesUtils.toPRTime(item.lastModified),
+          guid: item.guid,
+          syncChangeCounter: syncChangeDelta,
+          syncStatus,
+          rootId,
+        }));
+        await db.executeCached(
+          `INSERT INTO moz_bookmarks (fk, type, parent, position, title,
+                                    dateAdded, lastModified, guid,
+                                    syncChangeCounter, syncStatus)
+         VALUES (CASE WHEN :url ISNULL THEN NULL ELSE (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url) END, :type,
+         (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+         IFNULL(:index, (SELECT count(*) FROM moz_bookmarks WHERE parent = :rootId)),
+         NULLIF(:title, ''), :date_added, :last_modified, :guid,
+         :syncChangeCounter, :syncStatus)`,
+          items
+        );
+
+        // Remove stale tombstones for new items.
+        for (let chunk of lazy.PlacesUtils.chunkArray(
+          items,
+          db.variableLimit
+        )) {
+          await db.executeCached(
+            `DELETE FROM moz_bookmarks_deleted
+             WHERE guid IN (${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+            chunk.map(item => item.guid)
+          );
+        }
+
+        await setAncestorsLastModified(
+          db,
+          parent.guid,
+          lastAddedForParent,
+          syncChangeDelta
+        );
+      });
+
+      return items;
+    }
+  );
+}
+
+/**
+ * Handles special data on a bookmark, e.g. annotations, keywords, tags, charsets,
+ * inserting the data into the appropriate place.
+ *
+ * @param {Integer} itemId The ID of the item within the bookmarks database.
+ * @param {Object} item The bookmark item with possible special data to be inserted.
+ */
+async function handleBookmarkItemSpecialData(itemId, item) {
+  if ("keyword" in item && item.keyword) {
+    try {
+      await lazy.PlacesUtils.keywords.insert({
+        keyword: item.keyword,
+        url: item.url,
+        postData: item.postData,
+        source: item.source,
+      });
+    } catch (ex) {
+      console.error(
+        `Failed to insert keyword "${item.keyword} for ${item.url}":`,
+        ex
+      );
+    }
+  }
+  if ("tags" in item) {
+    try {
+      lazy.PlacesUtils.tagging.tagURI(
+        lazy.NetUtil.newURI(item.url),
+        item.tags,
+        item.source
+      );
+    } catch (ex) {
+      // Invalid tag child, skip it.
+      console.error(
+        `Unable to set tags "${item.tags.join(", ")}" for ${item.url}:`,
+        ex
+      );
+    }
+  }
+  if ("charset" in item && item.charset) {
+    try {
+      // UTF-8 is the default. If we are passed the value then set it to null,
+      // to ensure any charset is removed from the database.
+      let charset = item.charset;
+      if (item.charset.toLowerCase() == "utf-8") {
+        charset = null;
+      }
+
+      await lazy.PlacesUtils.history.update({
+        url: item.url,
+        annotations: new Map([[lazy.PlacesUtils.CHARSET_ANNO, charset]]),
+      });
+    } catch (ex) {
+      console.error(
+        `Failed to set charset "${item.charset}" for ${item.url}:`,
+        ex
+      );
+    }
+  }
+}
+
+// Query implementation.
+
+async function queryBookmarks(info) {
+  let queryParams = {
+    tags_folder: lazy.PlacesUtils.tagsFolderId,
+  };
+  // We're searching for bookmarks, so exclude tags.
+  let queryString = "WHERE b.parent <> :tags_folder";
+  queryString += " AND p.parent <> :tags_folder";
+
+  if (info.title) {
+    queryString += " AND b.title = :title";
+    queryParams.title = info.title;
+  }
+
+  if (info.url) {
+    queryString += " AND h.url_hash = hash(:url) AND h.url = :url";
+    queryParams.url = info.url;
+  }
+
+  if (info.query) {
+    queryString +=
+      " AND AUTOCOMPLETE_MATCH(:query, h.url, b.title, NULL, NULL, 1, 1, NULL, :matchBehavior, :searchBehavior, NULL) ";
+    queryParams.query = info.query;
+    queryParams.matchBehavior = MATCH_ANYWHERE_UNMODIFIED;
+    queryParams.searchBehavior = BEHAVIOR_BOOKMARK;
+  }
+
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: queryBookmarks",
+    async function (db) {
+      // _id, _childCount, _grandParentId and _parentId fields
+      // are required to be in the result by the converting function
+      // hence setting them to NULL
+      let rows = await db.executeCached(
+        `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+                b.dateAdded, b.lastModified, b.type,
+                IFNULL(b.title, '') AS title, h.url AS url, b.parent, p.parent,
+                NULL AS _id,
+                NULL AS _childCount,
+                NULL AS _grandParentId,
+                NULL AS _parentId,
+                NULL AS _syncStatus
+         FROM moz_bookmarks b
+         LEFT JOIN moz_bookmarks p ON p.id = b.parent
+         LEFT JOIN moz_places h ON h.id = b.fk
+         ${queryString}
+        `,
+        queryParams
+      );
+
+      return rowsToItemsArray(rows);
+    }
+  );
+}
+
+/**
+ * Internal fetch implementation.
+ * @param {object} info
+ *        The bookmark item to remove.
+ * @param {object} options
+ *        An options object supporting the following properties:
+ * @param {object} [options.concurrent]
+ *        Whether to use the concurrent read-only connection.
+ * @param {object} [options.db]
+ *        A specific connection to be used.
+ * @param {object} [options.ignoreInvalidURLs]
+ *        Whether invalid URLs should be ignored or throw an exception.
+ *
+ */
+async function fetchBookmark(info, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url, b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId, b.syncStatus AS _syncStatus
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE b.guid = :guid
+      `,
+      { guid: info.guid }
+    );
+
+    return rows.length
+      ? rowsToItemsArray(rows, !!options.ignoreInvalidURLs)[0]
+      : null;
+  };
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  if (options.db) {
+    return query(options.db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmark",
+    query
+  );
+}
+
+async function fetchBookmarkByPosition(info, options = {}) {
+  let query = async function (db) {
+    let index = info.index == Bookmarks.DEFAULT_INDEX ? null : info.index;
+    let rows = await db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url, b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId, b.syncStatus AS _syncStatus
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE p.guid = :parentGuid
+       AND b.position = IFNULL(:index, (SELECT count(*) - 1
+                                        FROM moz_bookmarks
+                                        WHERE parent = p.id))
+      `,
+      { parentGuid: info.parentGuid, index }
+    );
+
+    return rows.length ? rowsToItemsArray(rows)[0] : null;
+  };
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmarkByPosition",
+    query
+  );
+}
+
+async function fetchBookmarksByTags(info, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url, b.id AS _id, b.parent AS _parentId,
+              NULL AS _childCount,
+              p.parent AS _grandParentId, b.syncStatus AS _syncStatus,
+              (SELECT group_concat(pp.title ORDER BY pp.title)
+               FROM moz_bookmarks bb
+               JOIN moz_bookmarks pp ON pp.id = bb.parent
+               JOIN moz_bookmarks gg ON gg.id = pp.parent
+               WHERE bb.fk = h.id
+               AND gg.guid = '${Bookmarks.tagsGuid}'
+              ) AS _tags
+       FROM moz_bookmarks b
+       JOIN moz_bookmarks p ON p.id = b.parent
+       JOIN moz_bookmarks g ON g.id = p.parent
+       JOIN moz_places h ON h.id = b.fk
+       WHERE g.guid <> '${Bookmarks.tagsGuid}'
+       AND b.fk IN (
+          SELECT b2.fk FROM moz_bookmarks b2
+          JOIN moz_bookmarks p2 ON p2.id = b2.parent
+          JOIN moz_bookmarks g2 ON g2.id = p2.parent
+          WHERE g2.guid = '${Bookmarks.tagsGuid}'
+          AND lower(p2.title) IN (
+            ${new Array(info.tags.length).fill("?").join(",")}
+          )
+          GROUP BY b2.fk HAVING count(*) = ${info.tags.length}
+       )
+       ORDER BY b.lastModified DESC
+      `,
+      info.tags.map(t => t.toLowerCase())
+    );
+
+    return rows.length ? rowsToItemsArray(rows) : null;
+  };
+
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmarksByTags",
+    query
+  );
+}
+
+async function fetchBookmarksByGUIDPrefix(info, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url, b.id AS _id, b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              p.parent AS _grandParentId, b.syncStatus AS _syncStatus
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE b.guid LIKE :guidPrefix
+       ORDER BY b.lastModified DESC
+      `,
+      { guidPrefix: info.guidPrefix + "%" }
+    );
+
+    return rows.length ? rowsToItemsArray(rows) : null;
+  };
+
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmarksByGUIDPrefix",
+    query
+  );
+}
+
+async function fetchBookmarksByURL(info, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `/* do not warn (bug no): not worth to add an index */
+      SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url, b.id AS _id, b.parent AS _parentId,
+              NULL AS _childCount, /* Unused for now */
+              p.parent AS _grandParentId, b.syncStatus AS _syncStatus,
+              (SELECT group_concat(pp.title ORDER BY pp.title)
+               FROM moz_bookmarks bb
+               JOIN moz_bookmarks pp ON bb.parent = pp.id
+               JOIN moz_bookmarks gg ON pp.parent = gg.id
+               WHERE bb.fk = h.id
+               AND gg.guid = '${Bookmarks.tagsGuid}'
+              ) AS _tags
+      FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      JOIN moz_places h ON h.id = b.fk
+      WHERE h.url_hash = hash(:url) AND h.url = :url
+      AND _grandParentId <> :tagsFolderId
+      ORDER BY b.lastModified DESC
+      `,
+      {
+        url: info.url.href,
+        tagsFolderId: lazy.PlacesUtils.tagsFolderId,
+      }
+    );
+
+    return rows.length ? rowsToItemsArray(rows) : null;
+  };
+
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmarksByURL",
+    query
+  );
+}
+
+async function fetchBookmarksByParentGUID(info, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+              b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+              h.url AS url,
+              b.id AS _id,
+              b.parent AS _parentId,
+              (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+              NULL AS _grandParentId,
+              NULL AS _syncStatus
+       FROM moz_bookmarks b
+       LEFT JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       WHERE p.guid = :parentGuid
+       ORDER BY b.position ASC
+      `,
+      { parentGuid: info.parentGuid }
+    );
+
+    return rows.length ? rowsToItemsArray(rows) : null;
+  };
+
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchBookmarksByParentGUID",
+    query
+  );
+}
+
+function fetchRecentBookmarks(numberOfItems) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: fetchRecentBookmarks",
+    async function (db) {
+      let rows = await db.executeCached(
+        `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+                b.dateAdded, b.lastModified, b.type,
+                IFNULL(b.title, '') AS title, h.url AS url, b.id AS _id,
+                b.parent AS _parentId, NULL AS _childCount,
+                NULL AS _grandParentId, NULL AS _syncStatus
+        FROM moz_bookmarks b
+        JOIN moz_bookmarks p ON p.id = b.parent
+        JOIN moz_places h ON h.id = b.fk
+        WHERE p.parent <> :tagsFolderId
+        AND b.type = :type
+        AND url_hash NOT BETWEEN hash("place", "prefix_lo")
+                              AND hash("place", "prefix_hi")
+        ORDER BY b.dateAdded DESC, b.ROWID DESC
+        LIMIT :numberOfItems
+        `,
+        {
+          tagsFolderId: lazy.PlacesUtils.tagsFolderId,
+          type: Bookmarks.TYPE_BOOKMARK,
+          numberOfItems,
+        }
+      );
+
+      return rows.length ? rowsToItemsArray(rows) : [];
+    }
+  );
+}
+
+async function fetchBookmarksByParent(db, info) {
+  let rows = await db.executeCached(
+    `SELECT b.guid, IFNULL(p.guid, '') AS parentGuid, b.position AS 'index',
+            b.dateAdded, b.lastModified, b.type, IFNULL(b.title, '') AS title,
+            h.url AS url, b.id AS _id, b.parent AS _parentId,
+            (SELECT count(*) FROM moz_bookmarks WHERE parent = b.id) AS _childCount,
+            p.parent AS _grandParentId, b.syncStatus AS _syncStatus
+     FROM moz_bookmarks b
+     LEFT JOIN moz_bookmarks p ON p.id = b.parent
+     LEFT JOIN moz_places h ON h.id = b.fk
+     WHERE p.guid = :parentGuid
+     ORDER BY b.position ASC
+    `,
+    { parentGuid: info.parentGuid }
+  );
+
+  return rowsToItemsArray(rows);
+}
+
+// Remove implementation.
+
+function removeBookmarks(items, options) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: removeBookmarks",
+    async function (db) {
+      let urls = [];
+
+      await db.executeTransaction(async function transaction() {
+        // We use a map for its de-duplication properties.
+        let parents = new Map();
+        let syncChangeDelta =
+          lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(
+            options.source
+          );
+
+        for (let item of items) {
+          parents.set(item.parentGuid, item._parentId);
+
+          // If it's a folder, remove its contents first.
+          if (item.type == Bookmarks.TYPE_FOLDER) {
+            if (
+              options.preventRemovalOfNonEmptyFolders &&
+              item._childCount > 0
+            ) {
+              throw new Error("Cannot remove a non-empty folder.");
+            }
+            urls = urls.concat(
+              await removeFoldersContents(db, [item.guid], options)
+            );
+          }
+        }
+
+        for (let chunk of lazy.PlacesUtils.chunkArray(
+          items,
+          db.variableLimit
+        )) {
+          // Remove the bookmarks.
+          await db.executeCached(
+            `DELETE FROM moz_bookmarks
+             WHERE guid IN (${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+            chunk.map(item => item.guid)
+          );
+        }
+
+        for (let [parentGuid, parentId] of parents.entries()) {
+          // Now recalculate the positions.
+          await db.executeCached(
+            `WITH positions(id, pos, seq) AS (
+            SELECT id, position AS pos,
+                   (row_number() OVER (ORDER BY position)) - 1 AS seq
+            FROM moz_bookmarks
+            WHERE parent = :parentId
+          )
+          UPDATE moz_bookmarks
+            SET position = (SELECT seq FROM positions WHERE positions.id = moz_bookmarks.id)
+            WHERE id IN (SELECT id FROM positions WHERE seq <> pos)
+        `,
+            { parentId }
+          );
+
+          // Mark this parent as changed.
+          await setAncestorsLastModified(
+            db,
+            parentGuid,
+            new Date(),
+            syncChangeDelta
+          );
+        }
+
+        for (let i = 0; i < items.length; i++) {
+          const item = items[i];
+          // For the notifications, we may need to adjust indexes if there are more
+          // than one of the same item in the folder. This makes sure that we notify
+          // the index of the item when it was removed, rather than the original index.
+          for (let j = i + 1; j < items.length; j++) {
+            if (
+              items[j]._parentId == item._parentId &&
+              items[j].index > item.index
+            ) {
+              items[j].index--;
+            }
+          }
+          if (item._grandParentId == lazy.PlacesUtils.tagsFolderId) {
+            // If we're removing a tag entry, increment the change counter for all
+            // bookmarks with the tagged URL.
+            await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+              db,
+              item.url,
+              syncChangeDelta
+            );
+          }
+
+          await adjustSeparatorsSyncCounter(
+            db,
+            item._parentId,
+            item.index,
+            syncChangeDelta
+          );
+        }
+
+        // Write tombstones for the removed items.
+        await insertTombstones(db, items, syncChangeDelta);
+      });
+
+      urls = urls.concat(items.map(item => item.url).filter(item => item));
+      if (urls.length) {
+        await lazy.PlacesUtils.keywords.removeFromURLsIfNotBookmarked(urls);
+      }
+    }
+  );
+}
+
+// Reorder implementation.
+
+function reorderChildren(parent, orderedChildrenGuids, options) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: reorderChildren",
+    db =>
+      db.executeTransaction(async function () {
+        // Fetch old indices for the notifications.
+        const oldIndices = new Map();
+        (
+          await db.executeCached(
+            `SELECT guid, position FROM moz_bookmarks WHERE parent = :parentId`,
+            { parentId: parent._id }
+          )
+        ).forEach(r =>
+          oldIndices.set(
+            r.getResultByName("guid"),
+            r.getResultByName("position")
+          )
+        );
+        // By the time the caller collects guids and the time reorder is invoked
+        // new bookmarks may appear, and the passed-in list becomes incomplete.
+        // To avoid unnecessary work then skip reorder if children are already
+        // in the requested sort order.
+        let lastIndex = 0,
+          needReorder = false;
+        for (let guid of orderedChildrenGuids) {
+          let requestedIndex = oldIndices.get(guid);
+          if (requestedIndex === undefined) {
+            // doesn't exist, just ignore it.
+            continue;
+          }
+          if (requestedIndex < lastIndex) {
+            needReorder = true;
+            break;
+          }
+          lastIndex = requestedIndex;
+        }
+        if (!needReorder) {
+          return [];
+        }
+
+        const valuesFragment = orderedChildrenGuids
+          .map((g, i) => `("${g}", ${i})`)
+          .join();
+        await db.execute(
+          `UPDATE moz_bookmarks
+           SET position = sorted.pos,
+               lastModified = :lastModified
+           FROM (
+             WITH fixed(guid, pos) AS (
+               VALUES ${valuesFragment}
+             )
+             SELECT b.id,
+                    row_number() OVER (ORDER BY CASE WHEN fixed.pos IS NULL THEN 1 ELSE 0 END ASC, fixed.pos ASC, position ASC) - 1 AS pos
+             FROM moz_bookmarks b
+             LEFT JOIN fixed ON b.guid = fixed.guid
+             WHERE parent = :parentId
+           ) AS sorted
+           WHERE sorted.id = moz_bookmarks.id`,
+          {
+            parentId: parent._id,
+            lastModified: lazy.PlacesUtils.toPRTime(options.lastModified),
+          }
+        );
+
+        let syncChangeDelta =
+          lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(
+            options.source
+          );
+        await setAncestorsLastModified(
+          db,
+          parent.guid,
+          options.lastModified,
+          syncChangeDelta
+        );
+        // Fetch bookmarks for the notifications, adding _oldIndex to each.
+        return (
+          await fetchBookmarksByParent(db, {
+            parentGuid: parent.guid,
+          })
+        ).map(c => {
+          // We're not returning these objects to the caller, but just in case
+          // we'd decide to do it in the future, make sure this will be removed.
+          // See rowsToItemsArray() for additional details.
+          Object.defineProperty(c, "_oldIndex", {
+            value: oldIndices.get(c.guid) || 0,
+            enumerable: false,
+            configurable: true,
+          });
+          return c;
+        });
+      })
+  );
+}
+
+// Helpers.
+
+/**
+ * Merges objects into a new object, included non-enumerable properties.
+ *
+ * @param sources
+ *        source objects to merge.
+ * @return a new object including all properties from the source objects.
+ */
+function mergeIntoNewObject(...sources) {
+  let dest = {};
+  for (let src of sources) {
+    for (let prop of Object.getOwnPropertyNames(src)) {
+      Object.defineProperty(
+        dest,
+        prop,
+        Object.getOwnPropertyDescriptor(src, prop)
+      );
+    }
+  }
+  return dest;
+}
+
+/**
+ * Remove properties that have the same value across two bookmark objects.
+ *
+ * @param dest
+ *        destination bookmark object.
+ * @param src
+ *        source bookmark object.
+ * @return a cleaned up bookmark object.
+ * @note "guid" is never removed.
+ */
+function removeSameValueProperties(dest, src) {
+  for (let prop in dest) {
+    let remove = false;
+    switch (prop) {
+      case "lastModified":
+      case "dateAdded":
+        remove =
+          src.hasOwnProperty(prop) &&
+          dest[prop].getTime() == src[prop].getTime();
+        break;
+      case "url":
+        remove = src.hasOwnProperty(prop) && dest[prop].href == src[prop].href;
+        break;
+      default:
+        remove = dest[prop] == src[prop];
+    }
+    if (remove && prop != "guid") {
+      delete dest[prop];
+    }
+  }
+}
+
+/**
+ * Convert an array of mozIStorageRow objects to an array of bookmark objects.
+ *
+ * @param {Array} rows
+ *        the array of mozIStorageRow objects.
+ * @param {Boolean} ignoreInvalidURLs
+ *        whether to ignore invalid urls (leaving the url property undefined)
+ *        or throw.
+ * @return an array of bookmark objects.
+ */
+function rowsToItemsArray(rows, ignoreInvalidURLs = false) {
+  return rows.map(row => {
+    let item = {};
+    for (let prop of ["guid", "index", "type", "title"]) {
+      item[prop] = row.getResultByName(prop);
+    }
+    for (let prop of ["dateAdded", "lastModified"]) {
+      let value = row.getResultByName(prop);
+      if (value) {
+        item[prop] = lazy.PlacesUtils.toDate(value);
+      }
+    }
+    let parentGuid = row.getResultByName("parentGuid");
+    if (parentGuid) {
+      item.parentGuid = parentGuid;
+    }
+    let url = row.getResultByName("url");
+    if (url) {
+      try {
+        item.url = new URL(url);
+      } catch (ex) {
+        if (!ignoreInvalidURLs) {
+          throw ex;
+        }
+      }
+    }
+
+    // All the private properties below this point should not be returned to the
+    // API consumer, thus they are non-enumerable and removed through
+    // Object.assign just before the object is returned.
+    // Configurable is set to support mergeIntoNewObject overwrites.
+
+    for (let prop of [
+      "_id",
+      "_parentId",
+      "_childCount",
+      "_grandParentId",
+      "_syncStatus",
+    ]) {
+      let val = row.getResultByName(prop);
+      if (val !== null) {
+        Object.defineProperty(item, prop, {
+          value: val,
+          enumerable: false,
+          configurable: true,
+        });
+      }
+    }
+
+    try {
+      let tags = row.getResultByName("_tags");
+      Object.defineProperty(item, "_tags", {
+        value: tags
+          ? tags
+              .split(",")
+              .sort((a, b) => a.toLowerCase().localeCompare(b.toLowerCase()))
+          : [],
+        enumerable: false,
+        configurable: true,
+      });
+    } catch (ex) {
+      // `tags` not fetched, don't add it.
+    }
+
+    return item;
+  });
+}
+
+function validateBookmarkObject(name, input, behavior) {
+  return lazy.PlacesUtils.validateItemProperties(
+    name,
+    lazy.PlacesUtils.BOOKMARK_VALIDATORS,
+    input,
+    behavior
+  );
+}
+
+/**
+ * Updates lastModified for all the ancestors of a given folder GUID.
+ *
+ * @param db
+ *        the Sqlite.sys.mjs connection handle.
+ * @param folderGuid
+ *        the GUID of the folder whose ancestors should be updated.
+ * @param time
+ *        a Date object to use for the update.
+ *
+ * @note the folder itself is also updated.
+ */
+var setAncestorsLastModified = async function (
+  db,
+  folderGuid,
+  time,
+  syncChangeDelta
+) {
+  await db.executeCached(
+    `WITH RECURSIVE
+     ancestors(aid) AS (
+       SELECT id FROM moz_bookmarks WHERE guid = :guid
+       UNION ALL
+       SELECT parent FROM moz_bookmarks
+       JOIN ancestors ON id = aid
+       WHERE type = :type
+     )
+     UPDATE moz_bookmarks SET lastModified = :time
+     WHERE id IN ancestors
+    `,
+    {
+      guid: folderGuid,
+      type: Bookmarks.TYPE_FOLDER,
+      time: lazy.PlacesUtils.toPRTime(time),
+    }
+  );
+
+  if (syncChangeDelta) {
+    // Flag the folder as having a change.
+    await db.executeCached(
+      `
+      UPDATE moz_bookmarks SET
+        syncChangeCounter = syncChangeCounter + :syncChangeDelta
+      WHERE guid = :guid`,
+      { guid: folderGuid, syncChangeDelta }
+    );
+  }
+};
+
+/**
+ * Remove all descendants of one or more bookmark folders.
+ *
+ * @param {Object} db
+ *        the Sqlite.sys.mjs connection handle.
+ * @param {Array} folderGuids
+ *        array of folder guids.
+ * @return {Array}
+ *         An array of the affected urls.
+ */
+var removeFoldersContents = async function (db, folderGuids, options) {
+  let syncChangeDelta = lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(
+    options.source
+  );
+
+  let itemsRemoved = [];
+  for (let folderGuid of folderGuids) {
+    let rows = await db.executeCached(
+      `WITH RECURSIVE
+       descendants(did) AS (
+         SELECT b.id FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON b.parent = p.id
+         WHERE p.guid = :folderGuid
+         UNION ALL
+         SELECT id FROM moz_bookmarks
+         JOIN descendants ON parent = did
+       )
+       SELECT b.id AS _id, b.parent AS _parentId, b.position AS 'index',
+              b.type, url, b.guid, p.guid AS parentGuid, b.dateAdded,
+              b.lastModified, IFNULL(b.title, '') AS title,
+              p.parent AS _grandParentId, NULL AS _childCount,
+              b.syncStatus AS _syncStatus
+       FROM descendants
+       /* The usage of CROSS JOIN is not random, it tells the optimizer
+          to retain the original rows order, so the hierarchy is respected */
+       CROSS JOIN moz_bookmarks b ON did = b.id
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON b.fk = h.id`,
+      { folderGuid }
+    );
+
+    itemsRemoved = itemsRemoved.concat(rowsToItemsArray(rows, true));
+
+    await db.executeCached(
+      `WITH RECURSIVE
+       descendants(did) AS (
+         SELECT b.id FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON b.parent = p.id
+         WHERE p.guid = :folderGuid
+         UNION ALL
+         SELECT id FROM moz_bookmarks
+         JOIN descendants ON parent = did
+       )
+       DELETE FROM moz_bookmarks WHERE id IN descendants`,
+      { folderGuid }
+    );
+  }
+
+  // Write tombstones for removed items.
+  await insertTombstones(db, itemsRemoved, syncChangeDelta);
+
+  // Bump the change counter for all tagged bookmarks when removing tag
+  // folders.
+  await addSyncChangesForRemovedTagFolders(db, itemsRemoved, syncChangeDelta);
+
+  // TODO (Bug 1087576): this may leave orphan tags behind.
+
+  // Send onItemRemoved notifications to listeners.
+  // TODO (Bug 1087580): for the case of eraseEverything, this should send a
+  // single clear bookmarks notification rather than notifying for each
+  // bookmark.
+
+  // Notify listeners in reverse order to serve children before parents.
+  let { source = Bookmarks.SOURCES.DEFAULT } = options;
+  let notifications = [];
+  for (let item of itemsRemoved.reverse()) {
+    let isUntagging = item._grandParentId == lazy.PlacesUtils.tagsFolderId;
+    let url = "";
+    if (item.type == Bookmarks.TYPE_BOOKMARK) {
+      url = item.hasOwnProperty("url") ? item.url.href : null;
+    }
+    notifications.push(
+      new PlacesBookmarkRemoved({
+        id: item._id,
+        url,
+        title: item.title,
+        parentId: item._parentId,
+        index: item.index,
+        itemType: item.type,
+        guid: item.guid,
+        parentGuid: item.parentGuid,
+        source,
+        isTagging: isUntagging,
+        isDescendantRemoval:
+          !lazy.PlacesUtils.bookmarks.userContentRoots.includes(
+            item.parentGuid
+          ),
+      })
+    );
+
+    if (isUntagging) {
+      for (let entry of await fetchBookmarksByURL(item, true)) {
+        notifications.push(
+          new PlacesBookmarkTags({
+            id: entry._id,
+            itemType: entry.type,
+            url,
+            guid: entry.guid,
+            parentGuid: entry.parentGuid,
+            tags: entry._tags,
+            lastModified: entry.lastModified,
+            source,
+            isTagging: false,
+          })
+        );
+      }
+    }
+  }
+
+  if (notifications.length) {
+    PlacesObservers.notifyListeners(notifications);
+  }
+
+  return itemsRemoved.filter(item => "url" in item).map(item => item.url);
+};
+
+// Indicates whether we should write a tombstone for an item that has been
+// uploaded to the server. We ignore "NEW" and "UNKNOWN" items: "NEW" items
+// haven't been uploaded yet, and "UNKNOWN" items need a full reconciliation
+// with the server.
+function needsTombstone(item) {
+  return item._syncStatus == Bookmarks.SYNC_STATUS.NORMAL;
+}
+
+// Inserts tombstones for removed synced items.
+function insertTombstones(db, itemsRemoved, syncChangeDelta) {
+  if (!syncChangeDelta) {
+    return Promise.resolve();
+  }
+  let syncedItems = itemsRemoved.filter(needsTombstone);
+  if (!syncedItems.length) {
+    return Promise.resolve();
+  }
+  let dateRemoved = lazy.PlacesUtils.toPRTime(Date.now());
+  let valuesTable = syncedItems
+    .map(
+      item => `(
+    ${JSON.stringify(item.guid)},
+    ${dateRemoved}
+  )`
+    )
+    .join(",");
+  return db.execute(`
+    INSERT INTO moz_bookmarks_deleted (guid, dateRemoved)
+    VALUES ${valuesTable}`);
+}
+
+// Bumps the change counter for all bookmarks with URLs referenced in removed
+// tag folders.
+var addSyncChangesForRemovedTagFolders = async function (
+  db,
+  itemsRemoved,
+  syncChangeDelta
+) {
+  if (!syncChangeDelta) {
+    return;
+  }
+  for (let item of itemsRemoved) {
+    let isUntagging = item._grandParentId == lazy.PlacesUtils.tagsFolderId;
+    if (isUntagging) {
+      await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+        db,
+        item.url,
+        syncChangeDelta
+      );
+    }
+  }
+};
+
+function adjustSeparatorsSyncCounter(
+  db,
+  parentId,
+  startIndex,
+  syncChangeDelta
+) {
+  if (!syncChangeDelta) {
+    return Promise.resolve();
+  }
+
+  return db.executeCached(
+    `
+    UPDATE moz_bookmarks
+    SET syncChangeCounter = syncChangeCounter + :delta
+    WHERE parent = :parent AND position >= :start_index
+      AND type = :item_type
+    `,
+    {
+      delta: syncChangeDelta,
+      parent: parentId,
+      start_index: startIndex,
+      item_type: Bookmarks.TYPE_SEPARATOR,
+    }
+  );
+}
+
+/**
+ * Return the full path, from parent to root folder, of a bookmark.
+ *
+ * @param guid
+ *        The globally unique identifier of the item to determine the full
+ *        bookmark path for.
+ * @param options [optional]
+ *        an optional object whose properties describe options for the query:
+ *         - concurrent:  Queries concurrently to any writes, returning results
+ *                        faster. On the negative side, it may return stale
+ *                        information missing the currently ongoing write.
+ *         - db:          A specific connection to be used.
+ * @return {Promise} resolved when the query is complete.
+ * @resolves to an array of {guid, title} objects that represent the full path
+ *           from parent to root for the passed in bookmark.
+ * @rejects if an error happens while querying.
+ */
+async function retrieveFullBookmarkPath(guid, options = {}) {
+  let query = async function (db) {
+    let rows = await db.executeCached(
+      `WITH RECURSIVE parents(guid, _id, _parent, title) AS
+          (SELECT guid, id AS _id, parent AS _parent,
+                  IFNULL(title, '') AS title
+           FROM moz_bookmarks
+           WHERE guid = :pguid
+           UNION ALL
+           SELECT b.guid, b.id AS _id, b.parent AS _parent,
+                  IFNULL(b.title, '') AS title
+           FROM moz_bookmarks b
+           INNER JOIN parents ON b.id=parents._parent)
+        SELECT * FROM parents WHERE guid != :rootGuid;
+      `,
+      { pguid: guid, rootGuid: lazy.PlacesUtils.bookmarks.rootGuid }
+    );
+
+    return rows.reverse().map(r => ({
+      guid: r.getResultByName("guid"),
+      title: r.getResultByName("title"),
+    }));
+  };
+
+  if (options.concurrent) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    return query(db);
+  }
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.jsm: retrieveFullBookmarkPath",
+    query
+  );
+}
+
+/**
+ * Get detail of bookmarks of given GUID as Map.
+ *
+ * @param {Array} aGuids An array of item GUIDs.
+ * @return {Promise}
+ * @resolves to Map of bookmark details. The key is guid.
+ */
+async function getBookmarkDetailMap(aGuids) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "Bookmarks.geBookmarkDetails",
+    async db => {
+      const rows = await db.executeCached(
+        `
+          SELECT
+            b.guid,
+            b.id,
+            b.parent,
+            IFNULL(h.frecency, 0),
+            IFNULL(h.hidden, 0),
+            IFNULL(h.visit_count, 0),
+            h.last_visit_date,
+            (
+              SELECT group_concat(pp.title ORDER BY pp.title)
+              FROM moz_bookmarks bb
+              JOIN moz_bookmarks pp ON pp.id = bb.parent
+              JOIN moz_bookmarks gg ON gg.id = pp.parent
+              WHERE bb.fk = h.id
+              AND gg.guid = '${Bookmarks.tagsGuid}'
+            ),
+            t.guid, t.id, t.title
+          FROM moz_bookmarks b
+          LEFT JOIN moz_places h ON h.id = b.fk
+          LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(h.url)
+          WHERE b.guid IN (${lazy.PlacesUtils.sqlBindPlaceholders(aGuids)})
+          `,
+        aGuids
+      );
+
+      return new Map(
+        rows.map(row => {
+          const lastVisitDate = row.getResultByIndex(6);
+
+          return [
+            row.getResultByIndex(0),
+            {
+              id: row.getResultByIndex(1),
+              parentId: row.getResultByIndex(2),
+              frecency: row.getResultByIndex(3),
+              hidden: row.getResultByIndex(4),
+              visitCount: row.getResultByIndex(5),
+              lastVisitDate: lastVisitDate
+                ? lazy.PlacesUtils.toDate(lastVisitDate).getTime()
+                : null,
+              tags: row.getResultByIndex(7),
+              targetFolderGuid: row.getResultByIndex(8),
+              targetFolderItemId: row.getResultByIndex(9),
+              targetFolderTitle: row.getResultByIndex(10),
+            },
+          ];
+        })
+      );
+    }
+  );
+}
diff --git a/toolkit/components/places/Database.cpp b/toolkit/components/places/Database.cpp
new file mode 100644
index 0000000000..891c53156d
--- /dev/null
+++ b/toolkit/components/places/Database.cpp
@@ -0,0 +1,2284 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/StaticPrefs_places.h"
+
+#include "Database.h"
+
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIFile.h"
+
+#include "nsNavBookmarks.h"
+#include "nsNavHistory.h"
+#include "nsPlacesTables.h"
+#include "nsPlacesIndexes.h"
+#include "nsPlacesTriggers.h"
+#include "nsPlacesMacros.h"
+#include "nsVariant.h"
+#include "SQLFunctions.h"
+#include "Helpers.h"
+#include "nsFaviconService.h"
+
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "prenv.h"
+#include "prsystem.h"
+#include "nsPrintfCString.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Services.h"
+#include "mozilla/Unused.h"
+#include "mozIStorageService.h"
+#include "prtime.h"
+
+#include "nsXULAppAPI.h"
+
+// Time between corrupt database backups.
+#define RECENT_BACKUP_TIME_MICROSEC (int64_t)86400 * PR_USEC_PER_SEC  // 24H
+
+// Filename of the database.
+#define DATABASE_FILENAME u"places.sqlite"_ns
+// Filename of the icons database.
+#define DATABASE_FAVICONS_FILENAME u"favicons.sqlite"_ns
+
+// Set to the database file name when it was found corrupt by a previous
+// maintenance run.
+#define PREF_FORCE_DATABASE_REPLACEMENT \
+  "places.database.replaceDatabaseOnStartup"
+
+// Whether on corruption we should try to fix the database by cloning it.
+#define PREF_DATABASE_CLONEONCORRUPTION "places.database.cloneOnCorruption"
+
+// Set to specify the size of the places database growth increments in kibibytes
+#define PREF_GROWTH_INCREMENT_KIB "places.database.growthIncrementKiB"
+
+// Set to disable the default robust storage and use volatile, in-memory
+// storage without robust transaction flushing guarantees. This makes
+// SQLite use much less I/O at the cost of losing data when things crash.
+// The pref is only honored if an environment variable is set. The env
+// variable is intentionally named something scary to help prevent someone
+// from thinking it is a useful performance optimization they should enable.
+#define PREF_DISABLE_DURABILITY "places.database.disableDurability"
+
+#define PREF_PREVIEWS_ENABLED "places.previews.enabled"
+
+#define ENV_ALLOW_CORRUPTION \
+  "ALLOW_PLACES_DATABASE_TO_LOSE_DATA_AND_BECOME_CORRUPT"
+
+// Maximum size for the WAL file.
+// For performance reasons this should be as large as possible, so that more
+// transactions can fit into it, and the checkpoint cost is paid less often.
+// At the same time, since we use synchronous = NORMAL, an fsync happens only
+// at checkpoint time, so we don't want the WAL to grow too much and risk to
+// lose all the contained transactions on a crash.
+#define DATABASE_MAX_WAL_BYTES 2048000
+
+// Since exceeding the journal limit will cause a truncate, we allow a slightly
+// larger limit than DATABASE_MAX_WAL_BYTES to reduce the number of truncates.
+// This is the number of bytes the journal can grow over the maximum wal size
+// before being truncated.
+#define DATABASE_JOURNAL_OVERHEAD_BYTES 2048000
+
+#define BYTES_PER_KIBIBYTE 1024
+
+// How much time Sqlite can wait before returning a SQLITE_BUSY error.
+#define DATABASE_BUSY_TIMEOUT_MS 100
+
+// This annotation is no longer used & is obsolete, but here for migration.
+#define LAST_USED_ANNO "bookmarkPropertiesDialog/folderLastUsed"_ns
+// This is key in the meta table that the LAST_USED_ANNO is migrated to.
+#define LAST_USED_FOLDERS_META_KEY "places/bookmarks/edit/lastusedfolder"_ns
+
+// We use a fixed title for the mobile root to avoid marking the database as
+// corrupt if we can't look up the localized title in the string bundle. Sync
+// sets the title to the localized version when it creates the left pane query.
+#define MOBILE_ROOT_TITLE "mobile"
+
+// Legacy item annotation used by the old Sync engine.
+#define SYNC_PARENT_ANNO "sync/parent"
+
+using namespace mozilla;
+
+namespace mozilla::places {
+
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Helpers
+
+/**
+ * Get the filename for a corrupt database.
+ */
+nsString getCorruptFilename(const nsString& aDbFilename) {
+  return aDbFilename + u".corrupt"_ns;
+}
+/**
+ * Get the filename for a recover database.
+ */
+nsString getRecoverFilename(const nsString& aDbFilename) {
+  return aDbFilename + u".recover"_ns;
+}
+
+/**
+ * Checks whether exists a corrupt database file created not longer than
+ * RECENT_BACKUP_TIME_MICROSEC ago.
+ */
+bool isRecentCorruptFile(const nsCOMPtr<nsIFile>& aCorruptFile) {
+  MOZ_ASSERT(NS_IsMainThread());
+  bool fileExists = false;
+  if (NS_FAILED(aCorruptFile->Exists(&fileExists)) || !fileExists) {
+    return false;
+  }
+  PRTime lastMod = 0;
+  return NS_SUCCEEDED(aCorruptFile->GetLastModifiedTime(&lastMod)) &&
+         lastMod > 0 && (PR_Now() - lastMod) <= RECENT_BACKUP_TIME_MICROSEC;
+}
+
+/**
+ * Removes a file, optionally adding a suffix to the file name.
+ */
+void RemoveFileSwallowsErrors(const nsCOMPtr<nsIFile>& aFile,
+                              const nsString& aSuffix = u""_ns) {
+  nsCOMPtr<nsIFile> file;
+  MOZ_ALWAYS_SUCCEEDS(aFile->Clone(getter_AddRefs(file)));
+  if (!aSuffix.IsEmpty()) {
+    nsAutoString newFileName;
+    file->GetLeafName(newFileName);
+    newFileName.Append(aSuffix);
+    MOZ_ALWAYS_SUCCEEDS(file->SetLeafName(newFileName));
+  }
+  DebugOnly<nsresult> rv = file->Remove(false);
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to remove file.");
+}
+
+/**
+ * Sets the connection journal mode to one of the JOURNAL_* types.
+ *
+ * @param aDBConn
+ *        The database connection.
+ * @param aJournalMode
+ *        One of the JOURNAL_* types.
+ * @returns the current journal mode.
+ * @note this may return a different journal mode than the required one, since
+ *       setting it may fail.
+ */
+enum JournalMode SetJournalMode(nsCOMPtr<mozIStorageConnection>& aDBConn,
+                                enum JournalMode aJournalMode) {
+  MOZ_ASSERT(NS_IsMainThread());
+  nsAutoCString journalMode;
+  switch (aJournalMode) {
+    default:
+      MOZ_FALLTHROUGH_ASSERT("Trying to set an unknown journal mode.");
+      // Fall through to the default DELETE journal.
+    case JOURNAL_DELETE:
+      journalMode.AssignLiteral("delete");
+      break;
+    case JOURNAL_TRUNCATE:
+      journalMode.AssignLiteral("truncate");
+      break;
+    case JOURNAL_MEMORY:
+      journalMode.AssignLiteral("memory");
+      break;
+    case JOURNAL_WAL:
+      journalMode.AssignLiteral("wal");
+      break;
+  }
+
+  nsCOMPtr<mozIStorageStatement> statement;
+  nsAutoCString query(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA journal_mode = ");
+  query.Append(journalMode);
+  aDBConn->CreateStatement(query, getter_AddRefs(statement));
+  NS_ENSURE_TRUE(statement, JOURNAL_DELETE);
+
+  bool hasResult = false;
+  if (NS_SUCCEEDED(statement->ExecuteStep(&hasResult)) && hasResult &&
+      NS_SUCCEEDED(statement->GetUTF8String(0, journalMode))) {
+    if (journalMode.EqualsLiteral("delete")) {
+      return JOURNAL_DELETE;
+    }
+    if (journalMode.EqualsLiteral("truncate")) {
+      return JOURNAL_TRUNCATE;
+    }
+    if (journalMode.EqualsLiteral("memory")) {
+      return JOURNAL_MEMORY;
+    }
+    if (journalMode.EqualsLiteral("wal")) {
+      return JOURNAL_WAL;
+    }
+    MOZ_ASSERT(false, "Got an unknown journal mode.");
+  }
+
+  return JOURNAL_DELETE;
+}
+
+nsresult CreateRoot(nsCOMPtr<mozIStorageConnection>& aDBConn,
+                    const nsCString& aRootName, const nsCString& aGuid,
+                    const nsCString& titleString, const int32_t position,
+                    int64_t& newId) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // A single creation timestamp for all roots so that the root folder's
+  // last modification time isn't earlier than its childrens' creation time.
+  static PRTime timestamp = 0;
+  if (!timestamp) timestamp = RoundedPRNow();
+
+  // Create a new bookmark folder for the root.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = aDBConn->CreateStatement(
+      nsLiteralCString(
+          "INSERT INTO moz_bookmarks "
+          "(type, position, title, dateAdded, lastModified, guid, parent, "
+          "syncChangeCounter, syncStatus) "
+          "VALUES (:item_type, :item_position, :item_title,"
+          ":date_added, :last_modified, :guid, "
+          "IFNULL((SELECT id FROM moz_bookmarks WHERE parent = 0), 0), "
+          "1, :sync_status)"),
+      getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) return rv;
+
+  rv = stmt->BindInt32ByName("item_type"_ns,
+                             nsINavBookmarksService::TYPE_FOLDER);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindInt32ByName("item_position"_ns, position);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindUTF8StringByName("item_title"_ns, titleString);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindInt64ByName("date_added"_ns, timestamp);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindInt64ByName("last_modified"_ns, timestamp);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindUTF8StringByName("guid"_ns, aGuid);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->BindInt32ByName("sync_status"_ns,
+                             nsINavBookmarksService::SYNC_STATUS_NEW);
+  if (NS_FAILED(rv)) return rv;
+  rv = stmt->Execute();
+  if (NS_FAILED(rv)) return rv;
+
+  newId = nsNavBookmarks::sLastInsertedItemId;
+  return NS_OK;
+}
+
+nsresult SetupDurability(nsCOMPtr<mozIStorageConnection>& aDBConn,
+                         int32_t aDBPageSize) {
+  nsresult rv;
+  if (PR_GetEnv(ENV_ALLOW_CORRUPTION) &&
+      Preferences::GetBool(PREF_DISABLE_DURABILITY, false)) {
+    // Volatile storage was requested. Use the in-memory journal (no
+    // filesystem I/O) and don't sync the filesystem after writing.
+    SetJournalMode(aDBConn, JOURNAL_MEMORY);
+    rv = aDBConn->ExecuteSimpleSQL("PRAGMA synchronous = OFF"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    // Be sure to set journal mode after page_size.  WAL would prevent the
+    // change otherwise.
+    if (JOURNAL_WAL == SetJournalMode(aDBConn, JOURNAL_WAL)) {
+      // Set the WAL journal size limit.
+      int32_t checkpointPages =
+          static_cast<int32_t>(DATABASE_MAX_WAL_BYTES / aDBPageSize);
+      nsAutoCString checkpointPragma("PRAGMA wal_autocheckpoint = ");
+      checkpointPragma.AppendInt(checkpointPages);
+      rv = aDBConn->ExecuteSimpleSQL(checkpointPragma);
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      // Ignore errors, if we fail here the database could be considered corrupt
+      // and we won't be able to go on, even if it's just matter of a bogus file
+      // system.  The default mode (DELETE) will be fine in such a case.
+      (void)SetJournalMode(aDBConn, JOURNAL_TRUNCATE);
+
+      // Set synchronous to FULL to ensure maximum data integrity, even in
+      // case of crashes or unclean shutdowns.
+      rv = aDBConn->ExecuteSimpleSQL("PRAGMA synchronous = FULL"_ns);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  // The journal is usually free to grow for performance reasons, but it never
+  // shrinks back.  Since the space taken may be problematic, limit its size.
+  nsAutoCString journalSizePragma("PRAGMA journal_size_limit = ");
+  journalSizePragma.AppendInt(DATABASE_MAX_WAL_BYTES +
+                              DATABASE_JOURNAL_OVERHEAD_BYTES);
+  (void)aDBConn->ExecuteSimpleSQL(journalSizePragma);
+
+  // Grow places in |growthIncrementKiB| increments to limit fragmentation on
+  // disk. By default, it's 5 MB.
+  int32_t growthIncrementKiB =
+      Preferences::GetInt(PREF_GROWTH_INCREMENT_KIB, 5 * BYTES_PER_KIBIBYTE);
+  if (growthIncrementKiB > 0) {
+    (void)aDBConn->SetGrowthIncrement(growthIncrementKiB * BYTES_PER_KIBIBYTE,
+                                      ""_ns);
+  }
+  return NS_OK;
+}
+
+nsresult AttachDatabase(nsCOMPtr<mozIStorageConnection>& aDBConn,
+                        const nsACString& aPath, const nsACString& aName) {
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = aDBConn->CreateStatement("ATTACH DATABASE :path AS "_ns + aName,
+                                         getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindUTF8StringByName("path"_ns, aPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // The journal limit must be set apart for each database.
+  nsAutoCString journalSizePragma("PRAGMA favicons.journal_size_limit = ");
+  journalSizePragma.AppendInt(DATABASE_MAX_WAL_BYTES +
+                              DATABASE_JOURNAL_OVERHEAD_BYTES);
+  Unused << aDBConn->ExecuteSimpleSQL(journalSizePragma);
+
+  return NS_OK;
+}
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// Database
+
+PLACES_FACTORY_SINGLETON_IMPLEMENTATION(Database, gDatabase)
+
+NS_IMPL_ISUPPORTS(Database, nsIObserver, nsISupportsWeakReference)
+
+Database::Database()
+    : mMainThreadStatements(mMainConn),
+      mMainThreadAsyncStatements(mMainConn),
+      mAsyncThreadStatements(mMainConn),
+      mDBPageSize(0),
+      mDatabaseStatus(nsINavHistoryService::DATABASE_STATUS_OK),
+      mClosed(false),
+      mClientsShutdown(new ClientsShutdownBlocker()),
+      mConnectionShutdown(new ConnectionShutdownBlocker(this)),
+      mMaxUrlLength(0),
+      mCacheObservers(TOPIC_PLACES_INIT_COMPLETE),
+      mRootId(-1),
+      mMenuRootId(-1),
+      mTagsRootId(-1),
+      mUnfiledRootId(-1),
+      mToolbarRootId(-1),
+      mMobileRootId(-1) {
+  MOZ_ASSERT(!XRE_IsContentProcess(),
+             "Cannot instantiate Places in the content process");
+  // Attempting to create two instances of the service?
+  MOZ_ASSERT(!gDatabase);
+  gDatabase = this;
+}
+
+already_AddRefed<nsIAsyncShutdownClient>
+Database::GetProfileChangeTeardownPhase() {
+  nsCOMPtr<nsIAsyncShutdownService> asyncShutdownSvc =
+      services::GetAsyncShutdownService();
+  MOZ_ASSERT(asyncShutdownSvc);
+  if (NS_WARN_IF(!asyncShutdownSvc)) {
+    return nullptr;
+  }
+
+  // Consumers of Places should shutdown before us, at profile-change-teardown.
+  nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase;
+  DebugOnly<nsresult> rv =
+      asyncShutdownSvc->GetProfileChangeTeardown(getter_AddRefs(shutdownPhase));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  return shutdownPhase.forget();
+}
+
+already_AddRefed<nsIAsyncShutdownClient>
+Database::GetProfileBeforeChangePhase() {
+  nsCOMPtr<nsIAsyncShutdownService> asyncShutdownSvc =
+      services::GetAsyncShutdownService();
+  MOZ_ASSERT(asyncShutdownSvc);
+  if (NS_WARN_IF(!asyncShutdownSvc)) {
+    return nullptr;
+  }
+
+  // Consumers of Places should shutdown before us, at profile-change-teardown.
+  nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase;
+  DebugOnly<nsresult> rv =
+      asyncShutdownSvc->GetProfileBeforeChange(getter_AddRefs(shutdownPhase));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  return shutdownPhase.forget();
+}
+
+Database::~Database() = default;
+
+already_AddRefed<mozIStorageAsyncStatement> Database::GetAsyncStatement(
+    const nsACString& aQuery) {
+  if (PlacesShutdownBlocker::sIsStarted || NS_FAILED(EnsureConnection())) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(NS_IsMainThread());
+  return mMainThreadAsyncStatements.GetCachedStatement(aQuery);
+}
+
+already_AddRefed<mozIStorageStatement> Database::GetStatement(
+    const nsACString& aQuery) {
+  if (PlacesShutdownBlocker::sIsStarted) {
+    return nullptr;
+  }
+  if (NS_IsMainThread()) {
+    if (NS_FAILED(EnsureConnection())) {
+      return nullptr;
+    }
+    return mMainThreadStatements.GetCachedStatement(aQuery);
+  }
+  // In the async case, the connection must have been started on the main-thread
+  // already.
+  MOZ_ASSERT(mMainConn);
+  return mAsyncThreadStatements.GetCachedStatement(aQuery);
+}
+
+already_AddRefed<nsIAsyncShutdownClient> Database::GetClientsShutdown() {
+  if (mClientsShutdown) return mClientsShutdown->GetClient();
+  return nullptr;
+}
+
+already_AddRefed<nsIAsyncShutdownClient> Database::GetConnectionShutdown() {
+  if (mConnectionShutdown) return mConnectionShutdown->GetClient();
+  return nullptr;
+}
+
+// static
+already_AddRefed<Database> Database::GetDatabase() {
+  if (PlacesShutdownBlocker::sIsStarted) {
+    return nullptr;
+  }
+  return GetSingleton();
+}
+
+nsresult Database::Init() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // DO NOT FAIL HERE, otherwise we would never break the cycle between this
+  // object and the shutdown blockers, causing unexpected leaks.
+
+  {
+    // First of all Places clients should block profile-change-teardown.
+    nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase =
+        GetProfileChangeTeardownPhase();
+    MOZ_ASSERT(shutdownPhase);
+    if (shutdownPhase) {
+      nsresult rv = shutdownPhase->AddBlocker(
+          static_cast<nsIAsyncShutdownBlocker*>(mClientsShutdown.get()),
+          NS_LITERAL_STRING_FROM_CSTRING(__FILE__), __LINE__, u""_ns);
+      if (NS_FAILED(rv)) {
+        // Might occur if we're already shutting down, see bug#1753165
+        PlacesShutdownBlocker::sIsStarted = true;
+        NS_WARNING("Cannot add shutdown blocker for profile-change-teardown");
+      }
+    }
+  }
+
+  {
+    // Then connection closing should block profile-before-change.
+    nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase =
+        GetProfileBeforeChangePhase();
+    MOZ_ASSERT(shutdownPhase);
+    if (shutdownPhase) {
+      nsresult rv = shutdownPhase->AddBlocker(
+          static_cast<nsIAsyncShutdownBlocker*>(mConnectionShutdown.get()),
+          NS_LITERAL_STRING_FROM_CSTRING(__FILE__), __LINE__, u""_ns);
+      if (NS_FAILED(rv)) {
+        // Might occur if we're already shutting down, see bug#1753165
+        PlacesShutdownBlocker::sIsStarted = true;
+        NS_WARNING("Cannot add shutdown blocker for profile-before-change");
+      }
+    }
+  }
+
+  // Finally observe profile shutdown notifications.
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    (void)os->AddObserver(this, TOPIC_PROFILE_CHANGE_TEARDOWN, true);
+  }
+  return NS_OK;
+}
+
+nsresult Database::EnsureConnection() {
+  // Run this only once.
+  if (mMainConn ||
+      mDatabaseStatus == nsINavHistoryService::DATABASE_STATUS_LOCKED) {
+    return NS_OK;
+  }
+  // Don't try to create a database too late.
+  if (PlacesShutdownBlocker::sIsStarted) {
+    return NS_ERROR_FAILURE;
+  }
+
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Database initialization must happen on the main-thread");
+
+  {
+    bool initSucceeded = false;
+    auto notify = MakeScopeExit([&]() {
+      // If the database connection cannot be opened, it may just be locked
+      // by third parties.  Set a locked state.
+      if (!initSucceeded) {
+        mMainConn = nullptr;
+        mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_LOCKED;
+      }
+      // Notify at the next tick, to avoid re-entrancy problems.
+      NS_DispatchToMainThread(
+          NewRunnableMethod("places::Database::EnsureConnection()", this,
+                            &Database::NotifyConnectionInitalized));
+    });
+
+    nsCOMPtr<mozIStorageService> storage =
+        do_GetService(MOZ_STORAGE_SERVICE_CONTRACTID);
+    NS_ENSURE_STATE(storage);
+
+    nsCOMPtr<nsIFile> profileDir;
+    nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                         getter_AddRefs(profileDir));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCOMPtr<nsIFile> databaseFile;
+    rv = profileDir->Clone(getter_AddRefs(databaseFile));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = databaseFile->Append(DATABASE_FILENAME);
+    NS_ENSURE_SUCCESS(rv, rv);
+    bool databaseExisted = false;
+    rv = databaseFile->Exists(&databaseExisted);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsAutoString corruptDbName;
+    if (NS_SUCCEEDED(Preferences::GetString(PREF_FORCE_DATABASE_REPLACEMENT,
+                                            corruptDbName)) &&
+        !corruptDbName.IsEmpty()) {
+      // If this pref is set, maintenance required a database replacement, due
+      // to integrity corruption. Be sure to clear the pref to avoid handling it
+      // more than once.
+      (void)Preferences::ClearUser(PREF_FORCE_DATABASE_REPLACEMENT);
+
+      // The database is corrupt, backup and replace it with a new one.
+      nsCOMPtr<nsIFile> fileToBeReplaced;
+      bool fileExists = false;
+      if (NS_SUCCEEDED(profileDir->Clone(getter_AddRefs(fileToBeReplaced))) &&
+          NS_SUCCEEDED(fileToBeReplaced->Exists(&fileExists)) && fileExists) {
+        rv = BackupAndReplaceDatabaseFile(storage, corruptDbName, true, false);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+
+    // Open the database file.  If it does not exist a new one will be created.
+    // Use an unshared connection, it will consume more memory but avoid shared
+    // cache contentions across threads.
+    rv = storage->OpenUnsharedDatabase(databaseFile,
+                                       mozIStorageService::CONNECTION_DEFAULT,
+                                       getter_AddRefs(mMainConn));
+    if (NS_SUCCEEDED(rv) && !databaseExisted) {
+      mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_CREATE;
+    } else if (rv == NS_ERROR_FILE_CORRUPTED) {
+      // The database is corrupt, backup and replace it with a new one.
+      rv = BackupAndReplaceDatabaseFile(storage, DATABASE_FILENAME, true, true);
+      // Fallback to catch-all handler.
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Initialize the database schema.  In case of failure the existing schema
+    // is is corrupt or incoherent, thus the database should be replaced.
+    bool databaseMigrated = false;
+    rv = SetupDatabaseConnection(storage);
+    bool shouldTryToCloneDb = true;
+    if (NS_SUCCEEDED(rv)) {
+      // Failing to initialize the schema may indicate a corruption.
+      rv = InitSchema(&databaseMigrated);
+      if (NS_FAILED(rv)) {
+        // Cloning the db on a schema migration may not be a good idea, since we
+        // may end up cloning the schema problems.
+        shouldTryToCloneDb = false;
+        if (rv == NS_ERROR_STORAGE_BUSY || rv == NS_ERROR_FILE_IS_LOCKED ||
+            rv == NS_ERROR_FILE_NO_DEVICE_SPACE ||
+            rv == NS_ERROR_OUT_OF_MEMORY) {
+          // The database is not corrupt, though some migration step failed.
+          // This may be caused by concurrent use of sync and async Storage APIs
+          // or by a system issue.
+          // The best we can do is trying again. If it should still fail, Places
+          // won't work properly and will be handled as LOCKED.
+          rv = InitSchema(&databaseMigrated);
+          if (NS_FAILED(rv)) {
+            rv = NS_ERROR_FILE_IS_LOCKED;
+          }
+        } else {
+          rv = NS_ERROR_FILE_CORRUPTED;
+        }
+      }
+    }
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      if (rv != NS_ERROR_FILE_IS_LOCKED) {
+        mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_CORRUPT;
+      }
+      // Some errors may not indicate a database corruption, for those cases we
+      // just bail out without throwing away a possibly valid places.sqlite.
+      if (rv == NS_ERROR_FILE_CORRUPTED) {
+        // Since we don't know which database is corrupt, we must replace both.
+        rv = BackupAndReplaceDatabaseFile(storage, DATABASE_FAVICONS_FILENAME,
+                                          false, false);
+        NS_ENSURE_SUCCESS(rv, rv);
+        rv = BackupAndReplaceDatabaseFile(storage, DATABASE_FILENAME,
+                                          shouldTryToCloneDb, true);
+        NS_ENSURE_SUCCESS(rv, rv);
+        // Try to initialize the new database again.
+        rv = SetupDatabaseConnection(storage);
+        NS_ENSURE_SUCCESS(rv, rv);
+        rv = InitSchema(&databaseMigrated);
+      }
+      // Bail out if we couldn't fix the database.
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    if (databaseMigrated) {
+      mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_UPGRADED;
+    }
+
+    // Initialize here all the items that are not part of the on-disk database,
+    // like views, temp triggers or temp tables.  The database should not be
+    // considered corrupt if any of the following fails.
+
+    rv = InitTempEntities();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = CheckRoots();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    initSucceeded = true;
+  }
+  return NS_OK;
+}
+
+nsresult Database::NotifyConnectionInitalized() {
+  MOZ_ASSERT(NS_IsMainThread());
+  // Notify about Places initialization.
+  nsCOMArray<nsIObserver> entries;
+  mCacheObservers.GetEntries(entries);
+  for (int32_t idx = 0; idx < entries.Count(); ++idx) {
+    MOZ_ALWAYS_SUCCEEDS(
+        entries[idx]->Observe(nullptr, TOPIC_PLACES_INIT_COMPLETE, nullptr));
+  }
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    MOZ_ALWAYS_SUCCEEDS(
+        obs->NotifyObservers(nullptr, TOPIC_PLACES_INIT_COMPLETE, nullptr));
+  }
+  return NS_OK;
+}
+
+nsresult Database::EnsureFaviconsDatabaseAttached(
+    const nsCOMPtr<mozIStorageService>& aStorage) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIFile> databaseFile;
+  NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                         getter_AddRefs(databaseFile));
+  NS_ENSURE_STATE(databaseFile);
+  nsresult rv = databaseFile->Append(DATABASE_FAVICONS_FILENAME);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsString iconsPath;
+  rv = databaseFile->GetPath(iconsPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool fileExists = false;
+  if (NS_SUCCEEDED(databaseFile->Exists(&fileExists)) && fileExists) {
+    return AttachDatabase(mMainConn, NS_ConvertUTF16toUTF8(iconsPath),
+                          "favicons"_ns);
+  }
+
+  // Open the database file, this will also create it.
+  nsCOMPtr<mozIStorageConnection> conn;
+  rv = aStorage->OpenUnsharedDatabase(databaseFile,
+                                      mozIStorageService::CONNECTION_DEFAULT,
+                                      getter_AddRefs(conn));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  {
+    // Ensure we'll close the connection when done.
+    auto cleanup = MakeScopeExit([&]() {
+      // We cannot use AsyncClose() here, because by the time we try to ATTACH
+      // this database, its transaction could be still be running and that would
+      // cause the ATTACH query to fail.
+      MOZ_ALWAYS_TRUE(NS_SUCCEEDED(conn->Close()));
+    });
+
+    // Enable incremental vacuum for this database. Since it will contain even
+    // large blobs and can be cleared with history, it's worth to have it.
+    // Note that it will be necessary to manually use PRAGMA incremental_vacuum.
+    rv = conn->ExecuteSimpleSQL("PRAGMA auto_vacuum = INCREMENTAL"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+#if !defined(HAVE_64BIT_BUILD)
+    // Ensure that temp tables are held in memory, not on disk, on 32 bit
+    // platforms.
+    rv = conn->ExecuteSimpleSQL("PRAGMA temp_store = MEMORY"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+#endif
+
+    int32_t defaultPageSize;
+    rv = conn->GetDefaultPageSize(&defaultPageSize);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = SetupDurability(conn, defaultPageSize);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // We are going to update the database, so everything from now on should be
+    // in a transaction for performances.
+    mozStorageTransaction transaction(conn, false);
+    // XXX Handle the error, bug 1696133.
+    Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+    rv = conn->ExecuteSimpleSQL(CREATE_MOZ_ICONS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(CREATE_IDX_MOZ_ICONS_ICONURLHASH);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(CREATE_MOZ_PAGES_W_ICONS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PAGES_W_ICONS_ICONURLHASH);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(CREATE_MOZ_ICONS_TO_PAGES);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = transaction.Commit();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // The scope exit will take care of closing the connection.
+  }
+
+  rv = AttachDatabase(mMainConn, NS_ConvertUTF16toUTF8(iconsPath),
+                      "favicons"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::BackupAndReplaceDatabaseFile(
+    nsCOMPtr<mozIStorageService>& aStorage, const nsString& aDbFilename,
+    bool aTryToClone, bool aReopenConnection) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aDbFilename.Equals(DATABASE_FILENAME)) {
+    mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_CORRUPT;
+  } else {
+    // Due to OS file lockings, attached databases can't be cloned properly,
+    // otherwise trying to reattach them later would fail.
+    aTryToClone = false;
+  }
+
+  nsCOMPtr<nsIFile> profDir;
+  nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                       getter_AddRefs(profDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIFile> databaseFile;
+  rv = profDir->Clone(getter_AddRefs(databaseFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = databaseFile->Append(aDbFilename);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If we already failed in the last 24 hours avoid to create another corrupt
+  // file, since doing so, in some situation, could cause us to create a new
+  // corrupt file at every try to access any Places service.  That is bad
+  // because it would quickly fill the user's disk space without any notice.
+  nsCOMPtr<nsIFile> corruptFile;
+  rv = profDir->Clone(getter_AddRefs(corruptFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsString corruptFilename = getCorruptFilename(aDbFilename);
+  rv = corruptFile->Append(corruptFilename);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isRecentCorruptFile(corruptFile)) {
+    // Ensure we never create more than one corrupt file.
+    nsCOMPtr<nsIFile> corruptFile;
+    rv = profDir->Clone(getter_AddRefs(corruptFile));
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsString corruptFilename = getCorruptFilename(aDbFilename);
+    rv = corruptFile->Append(corruptFilename);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = corruptFile->Remove(false);
+    if (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND) {
+      return rv;
+    }
+
+    nsCOMPtr<nsIFile> backup;
+    Unused << BackupDatabaseFile(databaseFile, corruptFilename, profDir,
+                                 getter_AddRefs(backup));
+  }
+
+  // If anything fails from this point on, we have a stale connection or
+  // database file, and there's not much more we can do.
+  // The only thing we can try to do is to replace the database on the next
+  // startup, and report the problem through telemetry.
+  {
+    enum eCorruptDBReplaceStage : int8_t {
+      stage_closing = 0,
+      stage_removing,
+      stage_reopening,
+      stage_replaced,
+      stage_cloning,
+      stage_cloned
+    };
+    eCorruptDBReplaceStage stage = stage_closing;
+    auto guard = MakeScopeExit([&]() {
+      // In case we failed to close the connection or remove the database file,
+      // we want to try again at the next startup.
+      if (stage == stage_closing || stage == stage_removing) {
+        Preferences::SetString(PREF_FORCE_DATABASE_REPLACEMENT, aDbFilename);
+      }
+      // Report the corruption through telemetry.
+      Telemetry::Accumulate(
+          Telemetry::PLACES_DATABASE_CORRUPTION_HANDLING_STAGE,
+          static_cast<int8_t>(stage));
+    });
+
+    // Close database connection if open.
+    if (mMainConn) {
+      rv = mMainConn->SpinningSynchronousClose();
+      NS_ENSURE_SUCCESS(rv, rv);
+      mMainConn = nullptr;
+    }
+
+    // Remove the broken database.
+    stage = stage_removing;
+    rv = databaseFile->Remove(false);
+    if (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND) {
+      return rv;
+    }
+
+    // Create a new database file and try to clone tables from the corrupt one.
+    bool cloned = false;
+    if (aTryToClone &&
+        Preferences::GetBool(PREF_DATABASE_CLONEONCORRUPTION, true)) {
+      stage = stage_cloning;
+      rv = TryToCloneTablesFromCorruptDatabase(aStorage, databaseFile);
+      if (NS_SUCCEEDED(rv)) {
+        // If we cloned successfully, we should not consider the database
+        // corrupt anymore, otherwise we could reimport default bookmarks.
+        mDatabaseStatus = nsINavHistoryService::DATABASE_STATUS_OK;
+        cloned = true;
+      }
+    }
+
+    if (aReopenConnection) {
+      // Use an unshared connection, it will consume more memory but avoid
+      // shared cache contentions across threads.
+      stage = stage_reopening;
+      rv = aStorage->OpenUnsharedDatabase(
+          databaseFile, mozIStorageService::CONNECTION_DEFAULT,
+          getter_AddRefs(mMainConn));
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    stage = cloned ? stage_cloned : stage_replaced;
+  }
+
+  return NS_OK;
+}
+
+nsresult Database::TryToCloneTablesFromCorruptDatabase(
+    const nsCOMPtr<mozIStorageService>& aStorage,
+    const nsCOMPtr<nsIFile>& aDatabaseFile) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsAutoString filename;
+  nsresult rv = aDatabaseFile->GetLeafName(filename);
+
+  nsCOMPtr<nsIFile> corruptFile;
+  rv = aDatabaseFile->Clone(getter_AddRefs(corruptFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = corruptFile->SetLeafName(getCorruptFilename(filename));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoString path;
+  rv = corruptFile->GetPath(path);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> recoverFile;
+  rv = aDatabaseFile->Clone(getter_AddRefs(recoverFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = recoverFile->SetLeafName(getRecoverFilename(filename));
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Ensure there's no previous recover file.
+  rv = recoverFile->Remove(false);
+  if (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND) {
+    return rv;
+  }
+
+  nsCOMPtr<mozIStorageConnection> conn;
+  auto guard = MakeScopeExit([&]() {
+    if (conn) {
+      Unused << conn->Close();
+    }
+    RemoveFileSwallowsErrors(recoverFile);
+  });
+
+  rv = aStorage->OpenUnsharedDatabase(recoverFile,
+                                      mozIStorageService::CONNECTION_DEFAULT,
+                                      getter_AddRefs(conn));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = AttachDatabase(conn, NS_ConvertUTF16toUTF8(path), "corrupt"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mozStorageTransaction transaction(conn, false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  // Copy the schema version.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  (void)conn->CreateStatement("PRAGMA corrupt.user_version"_ns,
+                              getter_AddRefs(stmt));
+  NS_ENSURE_TRUE(stmt, NS_ERROR_OUT_OF_MEMORY);
+  bool hasResult;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  int32_t schemaVersion = stmt->AsInt32(0);
+  rv = conn->SetSchemaVersion(schemaVersion);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Recreate the tables.
+  rv = conn->CreateStatement(
+      nsLiteralCString(
+          "SELECT name, sql FROM corrupt.sqlite_master "
+          "WHERE type = 'table' AND name BETWEEN 'moz_' AND 'moza'"),
+      getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    nsAutoCString name;
+    rv = stmt->GetUTF8String(0, name);
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsAutoCString query;
+    rv = stmt->GetUTF8String(1, query);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(query);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // Copy the table contents.
+    rv = conn->ExecuteSimpleSQL("INSERT INTO main."_ns + name +
+                                " SELECT * FROM corrupt."_ns + name);
+    if (NS_FAILED(rv)) {
+      rv = conn->ExecuteSimpleSQL("INSERT INTO main."_ns + name +
+                                  " SELECT * FROM corrupt."_ns + name +
+                                  " ORDER BY rowid DESC"_ns);
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Recreate the indices.  Doing this after data addition is faster.
+  rv = conn->CreateStatement(
+      nsLiteralCString(
+          "SELECT sql FROM corrupt.sqlite_master "
+          "WHERE type <> 'table' AND name BETWEEN 'moz_' AND 'moza'"),
+      getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+  hasResult = false;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    nsAutoCString query;
+    rv = stmt->GetUTF8String(0, query);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = conn->ExecuteSimpleSQL(query);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  rv = stmt->Finalize();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  MOZ_ALWAYS_SUCCEEDS(conn->Close());
+  conn = nullptr;
+  rv = recoverFile->RenameTo(nullptr, filename);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RemoveFileSwallowsErrors(corruptFile);
+  RemoveFileSwallowsErrors(corruptFile, u"-wal"_ns);
+  RemoveFileSwallowsErrors(corruptFile, u"-shm"_ns);
+
+  guard.release();
+  return NS_OK;
+}
+
+nsresult Database::SetupDatabaseConnection(
+    nsCOMPtr<mozIStorageService>& aStorage) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Using immediate transactions allows the main connection to retry writes
+  // that fail with `SQLITE_BUSY` because a cloned connection has locked the
+  // database for writing.
+  nsresult rv = mMainConn->SetDefaultTransactionType(
+      mozIStorageConnection::TRANSACTION_IMMEDIATE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // WARNING: any statement executed before setting the journal mode must be
+  // finalized, since SQLite doesn't allow changing the journal mode if there
+  // is any outstanding statement.
+
+  {
+    // Get the page size.  This may be different than the default if the
+    // database file already existed with a different page size.
+    nsCOMPtr<mozIStorageStatement> statement;
+    rv = mMainConn->CreateStatement(
+        nsLiteralCString(MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA page_size"),
+        getter_AddRefs(statement));
+    NS_ENSURE_SUCCESS(rv, rv);
+    bool hasResult = false;
+    rv = statement->ExecuteStep(&hasResult);
+    NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hasResult, NS_ERROR_FILE_CORRUPTED);
+    rv = statement->GetInt32(0, &mDBPageSize);
+    NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && mDBPageSize > 0,
+                   NS_ERROR_FILE_CORRUPTED);
+  }
+
+#if !defined(HAVE_64BIT_BUILD)
+  // Ensure that temp tables are held in memory, not on disk, on 32 bit
+  // platforms.
+  rv = mMainConn->ExecuteSimpleSQL(nsLiteralCString(
+      MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA temp_store = MEMORY"));
+  NS_ENSURE_SUCCESS(rv, rv);
+#endif
+
+  rv = SetupDurability(mMainConn, mDBPageSize);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString busyTimeoutPragma("PRAGMA busy_timeout = ");
+  busyTimeoutPragma.AppendInt(DATABASE_BUSY_TIMEOUT_MS);
+  (void)mMainConn->ExecuteSimpleSQL(busyTimeoutPragma);
+
+  // Enable FOREIGN KEY support. This is a strict requirement.
+  rv = mMainConn->ExecuteSimpleSQL(nsLiteralCString(
+      MOZ_STORAGE_UNIQUIFY_QUERY_STR "PRAGMA foreign_keys = ON"));
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_FILE_CORRUPTED);
+#ifdef DEBUG
+  {
+    // There are a few cases where setting foreign_keys doesn't work:
+    //  * in the middle of a multi-statement transaction
+    //  * if the SQLite library in use doesn't support them
+    // Since we need foreign_keys, let's at least assert in debug mode.
+    nsCOMPtr<mozIStorageStatement> stmt;
+    mMainConn->CreateStatement("PRAGMA foreign_keys"_ns, getter_AddRefs(stmt));
+    bool hasResult = false;
+    if (stmt && NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+      int32_t fkState = stmt->AsInt32(0);
+      MOZ_ASSERT(fkState, "Foreign keys should be enabled");
+    }
+  }
+#endif
+
+  // Attach the favicons database to the main connection.
+  rv = EnsureFaviconsDatabaseAttached(aStorage);
+  if (NS_FAILED(rv)) {
+    // The favicons database may be corrupt. Try to replace and reattach it.
+    nsCOMPtr<nsIFile> iconsFile;
+    rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                getter_AddRefs(iconsFile));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = iconsFile->Append(DATABASE_FAVICONS_FILENAME);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = iconsFile->Remove(false);
+    if (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND) {
+      return rv;
+    }
+    rv = EnsureFaviconsDatabaseAttached(aStorage);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Create favicons temp entities.
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_ICONS_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // We use our functions during migration, so initialize them now.
+  rv = InitFunctions();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::InitSchema(bool* aDatabaseMigrated) {
+  MOZ_ASSERT(NS_IsMainThread());
+  *aDatabaseMigrated = false;
+
+  // Get the database schema version.
+  int32_t currentSchemaVersion;
+  nsresult rv = mMainConn->GetSchemaVersion(&currentSchemaVersion);
+  NS_ENSURE_SUCCESS(rv, rv);
+  bool databaseInitialized = currentSchemaVersion > 0;
+
+  if (databaseInitialized &&
+      currentSchemaVersion == nsINavHistoryService::DATABASE_SCHEMA_VERSION) {
+    // The database is up to date and ready to go.
+    return NS_OK;
+  }
+
+  // We are going to update the database, so everything from now on should be in
+  // a transaction for performances.
+  mozStorageTransaction transaction(mMainConn, false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  if (databaseInitialized) {
+    // Migration How-to:
+    //
+    // 1. increment PLACES_SCHEMA_VERSION.
+    // 2. implement a method that performs upgrade to your version from the
+    //    previous one.
+    //
+    // NOTE: The downgrade process is pretty much complicated by the fact old
+    //       versions cannot know what a new version is going to implement.
+    //       The only thing we will do for downgrades is setting back the schema
+    //       version, so that next upgrades will run again the migration step.
+
+    if (currentSchemaVersion < nsINavHistoryService::DATABASE_SCHEMA_VERSION) {
+      *aDatabaseMigrated = true;
+
+      if (currentSchemaVersion < 52) {
+        // These are versions older than Firefox 68 ESR that are not supported
+        // anymore.  In this case it's safer to just replace the database.
+        return NS_ERROR_FILE_CORRUPTED;
+      }
+
+      // Firefox 62 uses schema version 52.
+      // Firefox 68 uses schema version 52. - This is an ESR.
+
+      if (currentSchemaVersion < 53) {
+        rv = MigrateV53Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 69 uses schema version 53
+      // Firefox 72 is a watershed release.
+
+      if (currentSchemaVersion < 54) {
+        rv = MigrateV54Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 81 uses schema version 54
+
+      if (currentSchemaVersion < 55) {
+        rv = MigrateV55Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      if (currentSchemaVersion < 56) {
+        rv = MigrateV56Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      if (currentSchemaVersion < 57) {
+        rv = MigrateV57Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 91 uses schema version 57
+
+      // The schema 58 migration is no longer needed.
+
+      // Firefox 92 uses schema version 58
+
+      // The schema 59 migration is no longer needed.
+
+      // Firefox 94 uses schema version 59
+
+      if (currentSchemaVersion < 60) {
+        rv = MigrateV60Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 96 uses schema version 60
+
+      if (currentSchemaVersion < 61) {
+        rv = MigrateV61Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // The schema 62 migration is no longer needed.
+
+      // Firefox 97 uses schema version 62
+
+      // The schema 63 migration is no longer needed.
+
+      // Firefox 98 uses schema version 63
+
+      // The schema 64 migration is no longer needed.
+
+      // Firefox 99 uses schema version 64
+
+      // The schema 65 migration is no longer needed.
+
+      // The schema 66 migration is no longer needed.
+
+      // Firefox 100 uses schema version 66
+
+      if (currentSchemaVersion < 67) {
+        rv = MigrateV67Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // The schema 68 migration is no longer needed.
+
+      // Firefox 103 uses schema version 68
+
+      if (currentSchemaVersion < 69) {
+        rv = MigrateV69Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 104 uses schema version 69
+
+      if (currentSchemaVersion < 70) {
+        rv = MigrateV70Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      if (currentSchemaVersion < 71) {
+        rv = MigrateV71Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 110 uses schema version 71
+
+      if (currentSchemaVersion < 72) {
+        rv = MigrateV72Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 111 uses schema version 72
+
+      if (currentSchemaVersion < 73) {
+        rv = MigrateV73Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 114  uses schema version 73
+
+      if (currentSchemaVersion < 74) {
+        rv = MigrateV74Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 115  uses schema version 74
+
+      if (currentSchemaVersion < 75) {
+        rv = MigrateV75Up();
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Firefox 118 uses schema version 75
+
+      // Schema Upgrades must add migration code here.
+      // >>> IMPORTANT! <<<
+      // NEVER MIX UP SYNC AND ASYNC EXECUTION IN MIGRATORS, YOU MAY LOCK THE
+      // CONNECTION AND CAUSE FURTHER STEPS TO FAIL.
+      // In case, set a bool and do the async work in the ScopeExit guard just
+      // before the migration steps.
+    }
+  } else {
+    // This is a new database, so we have to create all the tables and indices.
+
+    // moz_origins.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_ORIGINS);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_places.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_EXTRA);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_URL_HASH);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_REVHOST);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_VISITCOUNT);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_FRECENCY);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_LASTVISITDATE);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_GUID);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_ORIGIN_ID);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_ALT_FRECENCY);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_historyvisits.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_HISTORYVISITS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_HISTORYVISITS_EXTRA);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_HISTORYVISITS_PLACEDATE);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_HISTORYVISITS_FROMVISIT);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_HISTORYVISITS_VISITDATE);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_inputhistory.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_INPUTHISTORY);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_bookmarks.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_BOOKMARKS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_BOOKMARKS_DELETED);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_BOOKMARKS_PLACETYPE);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_BOOKMARKS_PARENTPOSITION);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv =
+        mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_BOOKMARKS_PLACELASTMODIFIED);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_BOOKMARKS_DATEADDED);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_BOOKMARKS_GUID);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_keywords.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_KEYWORDS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_KEYWORDS_PLACEPOSTDATA);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_anno_attributes.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_ANNO_ATTRIBUTES);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_annos.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_ANNOS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_ANNOS_PLACEATTRIBUTE);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_items_annos.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_ITEMS_ANNOS);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_ITEMSANNOS_PLACEATTRIBUTE);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_meta.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_META);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_places_metadata
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_METADATA);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(
+        CREATE_IDX_MOZ_PLACES_METADATA_PLACECREATED);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_METADATA_REFERRER);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_places_metadata_search_queries
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_METADATA_SEARCH_QUERIES);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // moz_previews_tombstones
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PREVIEWS_TOMBSTONES);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // The bookmarks roots get initialized in CheckRoots().
+  }
+
+  // Set the schema version to the current one.
+  rv = mMainConn->SetSchemaVersion(
+      nsINavHistoryService::DATABASE_SCHEMA_VERSION);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // ANY FAILURE IN THIS METHOD WILL CAUSE US TO MARK THE DATABASE AS CORRUPT
+  // AND TRY TO REPLACE IT.
+  // DO NOT PUT HERE ANYTHING THAT IS NOT RELATED TO INITIALIZATION OR MODIFYING
+  // THE DISK DATABASE.
+
+  return NS_OK;
+}
+
+nsresult Database::CheckRoots() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // If the database has just been created, skip straight to the part where
+  // we create the roots.
+  if (mDatabaseStatus == nsINavHistoryService::DATABASE_STATUS_CREATE) {
+    return EnsureBookmarkRoots(0, /* shouldReparentRoots */ false);
+  }
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      nsLiteralCString("SELECT guid, id, position, parent FROM moz_bookmarks "
+                       "WHERE guid IN ( "
+                       "'" ROOT_GUID "', '" MENU_ROOT_GUID
+                       "', '" TOOLBAR_ROOT_GUID "', "
+                       "'" TAGS_ROOT_GUID "', '" UNFILED_ROOT_GUID
+                       "', '" MOBILE_ROOT_GUID "' )"),
+      getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult;
+  nsAutoCString guid;
+  int32_t maxPosition = 0;
+  bool shouldReparentRoots = false;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    rv = stmt->GetUTF8String(0, guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    int64_t parentId = stmt->AsInt64(3);
+
+    if (guid.EqualsLiteral(ROOT_GUID)) {
+      mRootId = stmt->AsInt64(1);
+      shouldReparentRoots |= parentId != 0;
+    } else {
+      maxPosition = std::max(stmt->AsInt32(2), maxPosition);
+
+      if (guid.EqualsLiteral(MENU_ROOT_GUID)) {
+        mMenuRootId = stmt->AsInt64(1);
+      } else if (guid.EqualsLiteral(TOOLBAR_ROOT_GUID)) {
+        mToolbarRootId = stmt->AsInt64(1);
+      } else if (guid.EqualsLiteral(TAGS_ROOT_GUID)) {
+        mTagsRootId = stmt->AsInt64(1);
+      } else if (guid.EqualsLiteral(UNFILED_ROOT_GUID)) {
+        mUnfiledRootId = stmt->AsInt64(1);
+      } else if (guid.EqualsLiteral(MOBILE_ROOT_GUID)) {
+        mMobileRootId = stmt->AsInt64(1);
+      }
+      shouldReparentRoots |= parentId != mRootId;
+    }
+  }
+
+  rv = EnsureBookmarkRoots(maxPosition + 1, shouldReparentRoots);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::EnsureBookmarkRoots(const int32_t startPosition,
+                                       bool shouldReparentRoots) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsresult rv;
+
+  if (mRootId < 1) {
+    // The first root's title is an empty string.
+    rv = CreateRoot(mMainConn, "places"_ns, "root________"_ns, ""_ns, 0,
+                    mRootId);
+
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  int32_t position = startPosition;
+
+  // For the other roots, the UI doesn't rely on the value in the database, so
+  // just set it to something simple to make it easier for humans to read.
+  if (mMenuRootId < 1) {
+    rv = CreateRoot(mMainConn, "menu"_ns, "menu________"_ns, "menu"_ns,
+                    position, mMenuRootId);
+    if (NS_FAILED(rv)) return rv;
+    position++;
+  }
+
+  if (mToolbarRootId < 1) {
+    rv = CreateRoot(mMainConn, "toolbar"_ns, "toolbar_____"_ns, "toolbar"_ns,
+                    position, mToolbarRootId);
+    if (NS_FAILED(rv)) return rv;
+    position++;
+  }
+
+  if (mTagsRootId < 1) {
+    rv = CreateRoot(mMainConn, "tags"_ns, "tags________"_ns, "tags"_ns,
+                    position, mTagsRootId);
+    if (NS_FAILED(rv)) return rv;
+    position++;
+  }
+
+  if (mUnfiledRootId < 1) {
+    rv = CreateRoot(mMainConn, "unfiled"_ns, "unfiled_____"_ns, "unfiled"_ns,
+                    position, mUnfiledRootId);
+    if (NS_FAILED(rv)) return rv;
+    position++;
+  }
+
+  if (mMobileRootId < 1) {
+    int64_t mobileRootId = CreateMobileRoot();
+    if (mobileRootId <= 0) return NS_ERROR_FAILURE;
+    {
+      nsCOMPtr<mozIStorageStatement> mobileRootSyncStatusStmt;
+      rv = mMainConn->CreateStatement(
+          nsLiteralCString("UPDATE moz_bookmarks SET syncStatus = "
+                           ":sync_status WHERE id = :id"),
+          getter_AddRefs(mobileRootSyncStatusStmt));
+      if (NS_FAILED(rv)) return rv;
+
+      rv = mobileRootSyncStatusStmt->BindInt32ByName(
+          "sync_status"_ns, nsINavBookmarksService::SYNC_STATUS_NEW);
+      if (NS_FAILED(rv)) return rv;
+      rv = mobileRootSyncStatusStmt->BindInt64ByName("id"_ns, mobileRootId);
+      if (NS_FAILED(rv)) return rv;
+
+      rv = mobileRootSyncStatusStmt->Execute();
+      if (NS_FAILED(rv)) return rv;
+
+      mMobileRootId = mobileRootId;
+    }
+  }
+
+  if (!shouldReparentRoots) {
+    return NS_OK;
+  }
+
+  // At least one root had the wrong parent, so we need to ensure that
+  // all roots are parented correctly, fix their positions, and bump the
+  // Sync change counter.
+  rv = mMainConn->ExecuteSimpleSQL(nsLiteralCString(
+      "CREATE TEMP TRIGGER moz_ensure_bookmark_roots_trigger "
+      "AFTER UPDATE OF parent ON moz_bookmarks FOR EACH ROW "
+      "WHEN OLD.parent <> NEW.parent "
+      "BEGIN "
+      "UPDATE moz_bookmarks SET "
+      "syncChangeCounter = syncChangeCounter + 1 "
+      "WHERE id IN (OLD.parent, NEW.parent, NEW.id); "
+
+      "UPDATE moz_bookmarks SET "
+      "position = position - 1 "
+      "WHERE parent = OLD.parent AND position >= OLD.position; "
+
+      // Fix the positions of the root's old siblings. Since we've already
+      // moved the root, we need to exclude it from the subquery.
+      "UPDATE moz_bookmarks SET "
+      "position = IFNULL((SELECT MAX(position) + 1 FROM moz_bookmarks "
+      "WHERE parent = NEW.parent AND "
+      "id <> NEW.id), 0)"
+      "WHERE id = NEW.id; "
+      "END"));
+  if (NS_FAILED(rv)) return rv;
+  auto guard = MakeScopeExit([&]() {
+    Unused << mMainConn->ExecuteSimpleSQL(
+        "DROP TRIGGER moz_ensure_bookmark_roots_trigger"_ns);
+  });
+
+  nsCOMPtr<mozIStorageStatement> reparentStmt;
+  rv = mMainConn->CreateStatement(
+      nsLiteralCString(
+          "UPDATE moz_bookmarks SET "
+          "parent = CASE id WHEN :root_id THEN 0 ELSE :root_id END "
+          "WHERE id IN (:root_id, :menu_root_id, :toolbar_root_id, "
+          ":tags_root_id, "
+          ":unfiled_root_id, :mobile_root_id)"),
+      getter_AddRefs(reparentStmt));
+  if (NS_FAILED(rv)) return rv;
+
+  rv = reparentStmt->BindInt64ByName("root_id"_ns, mRootId);
+  if (NS_FAILED(rv)) return rv;
+  rv = reparentStmt->BindInt64ByName("menu_root_id"_ns, mMenuRootId);
+  if (NS_FAILED(rv)) return rv;
+  rv = reparentStmt->BindInt64ByName("toolbar_root_id"_ns, mToolbarRootId);
+  if (NS_FAILED(rv)) return rv;
+  rv = reparentStmt->BindInt64ByName("tags_root_id"_ns, mTagsRootId);
+  if (NS_FAILED(rv)) return rv;
+  rv = reparentStmt->BindInt64ByName("unfiled_root_id"_ns, mUnfiledRootId);
+  if (NS_FAILED(rv)) return rv;
+  rv = reparentStmt->BindInt64ByName("mobile_root_id"_ns, mMobileRootId);
+  if (NS_FAILED(rv)) return rv;
+
+  rv = reparentStmt->Execute();
+  if (NS_FAILED(rv)) return rv;
+
+  return NS_OK;
+}
+
+nsresult Database::InitFunctions() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsresult rv = GetUnreversedHostFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = MatchAutoCompleteFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = CalculateFrecencyFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = GenerateGUIDFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = IsValidGUIDFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = FixupURLFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = StoreLastInsertedIdFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = HashFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = GetQueryParamFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = GetPrefixFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = GetHostAndPortFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = StripPrefixAndUserinfoFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = IsFrecencyDecayingFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = NoteSyncChangeFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = InvalidateDaysOfHistoryFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = MD5HexFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = SetShouldStartFrecencyRecalculationFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = TargetFolderGuidFunction::create(mMainConn);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (StaticPrefs::places_frecency_pages_alternative_featureGate_AtStartup()) {
+    rv = CalculateAltFrecencyFunction::create(mMainConn);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult Database::InitTempEntities() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsresult rv =
+      mMainConn->ExecuteSimpleSQL(CREATE_HISTORYVISITS_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_HISTORYVISITS_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_PLACES_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_UPDATEORIGINSDELETE_TEMP);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_UPDATEORIGINSDELETE_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (Preferences::GetBool(PREF_PREVIEWS_ENABLED, false)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        CREATE_PLACES_AFTERDELETE_WPREVIEWS_TRIGGER);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_PLACES_AFTERDELETE_TRIGGER);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_PLACES_AFTERUPDATE_FRECENCY_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_PLACES_AFTERUPDATE_RECALC_FRECENCY_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_ORIGINS_AFTERUPDATE_RECALC_FRECENCY_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_ORIGINS_AFTERUPDATE_FRECENCY_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERUPDATE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_KEYWORDS_FOREIGNCOUNT_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_KEYWORDS_FOREIGNCOUNT_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      CREATE_KEYWORDS_FOREIGNCOUNT_AFTERUPDATE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv =
+      mMainConn->ExecuteSimpleSQL(CREATE_BOOKMARKS_DELETED_AFTERINSERT_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv =
+      mMainConn->ExecuteSimpleSQL(CREATE_BOOKMARKS_DELETED_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_PLACES_METADATA_AFTERDELETE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Create triggers to remove rows with empty json
+  rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_EXTRA_AFTERUPDATE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv =
+      mMainConn->ExecuteSimpleSQL(CREATE_MOZ_HISTORYVISITS_AFTERUPDATE_TRIGGER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV53Up() {
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement("SELECT 1 FROM moz_items_annos"_ns,
+                                           getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    // Likely we removed the table.
+    return NS_OK;
+  }
+
+  // Remove all item annotations but SYNC_PARENT_ANNO.
+  rv = mMainConn->CreateStatement(
+      nsLiteralCString(
+          "DELETE FROM moz_items_annos "
+          "WHERE anno_attribute_id NOT IN ( "
+          "  SELECT id FROM moz_anno_attributes WHERE name = :anno_name "
+          ") "),
+      getter_AddRefs(stmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindUTF8StringByName("anno_name"_ns,
+                                  nsLiteralCString(SYNC_PARENT_ANNO));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mMainConn->ExecuteSimpleSQL(nsLiteralCString(
+      "DELETE FROM moz_anno_attributes WHERE id IN ( "
+      "  SELECT id FROM moz_anno_attributes "
+      "  EXCEPT "
+      "  SELECT DISTINCT anno_attribute_id FROM moz_annos "
+      "  EXCEPT "
+      "  SELECT DISTINCT anno_attribute_id FROM moz_items_annos "
+      ")"));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV54Up() {
+  // Add an expiration column to moz_icons_to_pages.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT expire_ms FROM moz_icons_to_pages"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_icons_to_pages "
+        "ADD COLUMN expire_ms INTEGER NOT NULL DEFAULT 0 "_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Set all the zero-ed entries as expired today, they won't be removed until
+  // the next related page load.
+  rv = mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_icons_to_pages "
+      "SET expire_ms = strftime('%s','now','localtime','start "
+      "of day','utc') * 1000 "
+      "WHERE expire_ms = 0 "_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV55Up() {
+  // Add places metadata tables.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT id FROM moz_places_metadata"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    // Create the tables.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_METADATA);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // moz_places_metadata_search_queries.
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_METADATA_SEARCH_QUERIES);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV56Up() {
+  // Add places metadata (place_id, created_at) index.
+  return mMainConn->ExecuteSimpleSQL(
+      CREATE_IDX_MOZ_PLACES_METADATA_PLACECREATED);
+}
+
+nsresult Database::MigrateV57Up() {
+  // Add the scrolling columns to the metadata.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT scrolling_time FROM moz_places_metadata"_ns,
+      getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places_metadata "
+        "ADD COLUMN scrolling_time INTEGER NOT NULL DEFAULT 0 "_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  rv = mMainConn->CreateStatement(
+      "SELECT scrolling_distance FROM moz_places_metadata"_ns,
+      getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places_metadata "
+        "ADD COLUMN scrolling_distance INTEGER NOT NULL DEFAULT 0 "_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult Database::MigrateV60Up() {
+  // Add the site_name column to moz_places.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT site_name FROM moz_places"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places ADD COLUMN site_name TEXT"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult Database::MigrateV61Up() {
+  // Add previews tombstones table if necessary.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT hash FROM moz_previews_tombstones"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PREVIEWS_TOMBSTONES);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult Database::MigrateV67Up() {
+  // Align all input field in moz_inputhistory to lowercase. If there are
+  // multiple records that expresses the same input, use maximum use_count from
+  // them to carry on the experience of the past.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->ExecuteSimpleSQL(
+      "INSERT INTO moz_inputhistory "
+      "SELECT place_id, LOWER(input), use_count FROM moz_inputhistory "
+      "  WHERE LOWER(input) <> input "
+      "ON CONFLICT DO "
+      "  UPDATE SET use_count = MAX(use_count, EXCLUDED.use_count)"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DELETE FROM moz_inputhistory WHERE LOWER(input) <> input"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV69Up() {
+  // Add source and annotation column to places table.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT source FROM moz_historyvisits"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_historyvisits "
+        "ADD COLUMN source INTEGER DEFAULT 0 NOT NULL"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_historyvisits "
+        "ADD COLUMN triggeringPlaceId INTEGER"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV70Up() {
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT recalc_frecency FROM moz_places LIMIT 1 "_ns,
+      getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    // Add recalc_frecency column, indicating frecency has to be recalculated.
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places "
+        "ADD COLUMN recalc_frecency INTEGER NOT NULL DEFAULT 0 "_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // We must do the following updates regardless, for downgrade/upgrade cases.
+
+  // moz_origins frecency is, at the time of this migration, the sum of all the
+  // positive frecencies of pages linked to that origin. Frecencies that were
+  // set to negative to request recalculation are thus not accounted for, and
+  // since we're about to flip them to positive we should add them to their
+  // origin. Then we must also update origins stats.
+  // We ignore frecency = -1 because it's just an indication to recalculate
+  // frecency and not an actual frecency value that was flipped, thus it would
+  // not make sense to count it for the origin.
+  rv = mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_origins "
+      "SET frecency = frecency + abs_frecency "
+      "FROM (SELECT origin_id, ABS(frecency) AS abs_frecency FROM moz_places "
+      "WHERE frecency < -1) AS places "
+      "WHERE moz_origins.id = places.origin_id"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "INSERT OR REPLACE INTO moz_meta(key, value) VALUES "
+      "('origin_frecency_count', "
+      "(SELECT COUNT(*) FROM moz_origins WHERE frecency > 0) "
+      "), "
+      "('origin_frecency_sum', "
+      "(SELECT TOTAL(frecency) FROM moz_origins WHERE frecency > 0) "
+      "), "
+      "('origin_frecency_sum_of_squares', "
+      "(SELECT TOTAL(frecency * frecency) FROM moz_origins WHERE frecency > 0) "
+      ") "_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Now set recalc_frecency = 1 and positive frecency to any page having a
+  // negative frecency.
+  // Note we don't flip frecency = -1, since we skipped it above when updating
+  // origins, and it remains an acceptable value yet, until the recalculation.
+  rv = mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_places "
+      "SET recalc_frecency = 1, "
+      "    frecency = CASE WHEN frecency = -1 THEN -1 ELSE ABS(frecency) END "
+      "WHERE frecency < 0 "_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV71Up() {
+  // Fix the foreign counts. We ignore failures as the tables may not exist.
+  mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_places "
+      "SET foreign_count = foreign_count - 1 "
+      "WHERE id in (SELECT place_id FROM moz_places_metadata_snapshots)"_ns);
+  mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_places "
+      "SET foreign_count = foreign_count - 1 "
+      "WHERE id in (SELECT place_id FROM moz_session_to_places)"_ns);
+
+  // Remove unused snapshots and session tables and indexes.
+  nsresult rv = mMainConn->ExecuteSimpleSQL(
+      "DROP INDEX IF EXISTS moz_places_metadata_snapshots_pinnedindex"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP INDEX IF EXISTS moz_places_metadata_snapshots_extra_typeindex"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_places_metadata_groups_to_snapshots"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_places_metadata_snapshots_groups"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_places_metadata_snapshots_extra"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_places_metadata_snapshots"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_session_to_places"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = mMainConn->ExecuteSimpleSQL(
+      "DROP TABLE IF EXISTS moz_session_metadata"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult Database::MigrateV72Up() {
+  // Recalculate frecency of unvisited bookmarks.
+  nsresult rv = mMainConn->ExecuteSimpleSQL(
+      "UPDATE moz_places "
+      "SET recalc_frecency = 1 "
+      "WHERE foreign_count > 0 AND visit_count = 0"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+nsresult Database::MigrateV73Up() {
+  // Add recalc_frecency, alt_frecency and recalc_alt_frecency to moz_origins.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT recalc_frecency FROM moz_origins"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_origins "
+        "ADD COLUMN recalc_frecency INTEGER NOT NULL DEFAULT 0"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_origins "
+        "ADD COLUMN alt_frecency INTEGER"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_origins "
+        "ADD COLUMN recalc_alt_frecency INTEGER NOT NULL DEFAULT 0"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult Database::MigrateV74Up() {
+  // Add alt_frecency and recalc_alt_frecency to moz_places.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT alt_frecency FROM moz_places"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places "
+        "ADD COLUMN alt_frecency INTEGER"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(
+        "ALTER TABLE moz_places "
+        "ADD COLUMN recalc_alt_frecency INTEGER NOT NULL DEFAULT 0"_ns);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_IDX_MOZ_PLACES_ALT_FRECENCY);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult Database::MigrateV75Up() {
+  // Add *_extra tables for moz_places and moz_historyvisits
+  nsCOMPtr<mozIStorageStatement> stmt;
+  nsresult rv = mMainConn->CreateStatement(
+      "SELECT sync_json FROM moz_places_extra"_ns, getter_AddRefs(stmt));
+  if (NS_FAILED(rv)) {
+    nsresult rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_PLACES_EXTRA);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = mMainConn->ExecuteSimpleSQL(CREATE_MOZ_HISTORYVISITS_EXTRA);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+int64_t Database::CreateMobileRoot() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Create the mobile root, ignoring conflicts if one already exists (for
+  // example, if the user downgraded to an earlier release channel).
+  nsCOMPtr<mozIStorageStatement> createStmt;
+  nsresult rv = mMainConn->CreateStatement(
+      nsLiteralCString(
+          "INSERT OR IGNORE INTO moz_bookmarks "
+          "(type, title, dateAdded, lastModified, guid, position, parent) "
+          "SELECT :item_type, :item_title, :timestamp, :timestamp, :guid, "
+          "IFNULL((SELECT MAX(position) + 1 FROM moz_bookmarks p WHERE "
+          "p.parent = b.id), 0), b.id "
+          "FROM moz_bookmarks b WHERE b.parent = 0"),
+      getter_AddRefs(createStmt));
+  if (NS_FAILED(rv)) return -1;
+
+  rv = createStmt->BindInt32ByName("item_type"_ns,
+                                   nsINavBookmarksService::TYPE_FOLDER);
+  if (NS_FAILED(rv)) return -1;
+  rv = createStmt->BindUTF8StringByName("item_title"_ns,
+                                        nsLiteralCString(MOBILE_ROOT_TITLE));
+  if (NS_FAILED(rv)) return -1;
+  rv = createStmt->BindInt64ByName("timestamp"_ns, RoundedPRNow());
+  if (NS_FAILED(rv)) return -1;
+  rv = createStmt->BindUTF8StringByName("guid"_ns,
+                                        nsLiteralCString(MOBILE_ROOT_GUID));
+  if (NS_FAILED(rv)) return -1;
+
+  rv = createStmt->Execute();
+  if (NS_FAILED(rv)) return -1;
+
+  // Find the mobile root ID. We can't use the last inserted ID because the
+  // root might already exist, and we ignore on conflict.
+  nsCOMPtr<mozIStorageStatement> findIdStmt;
+  rv = mMainConn->CreateStatement(
+      "SELECT id FROM moz_bookmarks WHERE guid = :guid"_ns,
+      getter_AddRefs(findIdStmt));
+  if (NS_FAILED(rv)) return -1;
+
+  rv = findIdStmt->BindUTF8StringByName("guid"_ns,
+                                        nsLiteralCString(MOBILE_ROOT_GUID));
+  if (NS_FAILED(rv)) return -1;
+
+  bool hasResult = false;
+  rv = findIdStmt->ExecuteStep(&hasResult);
+  if (NS_FAILED(rv) || !hasResult) return -1;
+
+  int64_t rootId;
+  rv = findIdStmt->GetInt64(0, &rootId);
+  if (NS_FAILED(rv)) return -1;
+
+  return rootId;
+}
+
+void Database::Shutdown() {
+  // As the last step in the shutdown path, finalize the database handle.
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!mClosed);
+
+  // Break cycles with the shutdown blockers.
+  mClientsShutdown = nullptr;
+  nsCOMPtr<mozIStorageCompletionCallback> connectionShutdown =
+      std::move(mConnectionShutdown);
+
+  if (!mMainConn) {
+    // The connection has never been initialized. Just mark it as closed.
+    mClosed = true;
+    (void)connectionShutdown->Complete(NS_OK, nullptr);
+    return;
+  }
+
+#ifdef DEBUG
+  {
+    bool hasResult;
+    nsCOMPtr<mozIStorageStatement> stmt;
+
+    // Sanity check for missing guids.
+    nsresult rv =
+        mMainConn->CreateStatement(nsLiteralCString("SELECT 1 "
+                                                    "FROM moz_places "
+                                                    "WHERE guid IS NULL "),
+                                   getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found a page without a GUID!");
+    rv = mMainConn->CreateStatement(nsLiteralCString("SELECT 1 "
+                                                     "FROM moz_bookmarks "
+                                                     "WHERE guid IS NULL "),
+                                    getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found a bookmark without a GUID!");
+
+    // Sanity check for unrounded dateAdded and lastModified values (bug
+    // 1107308).
+    rv = mMainConn->CreateStatement(
+        nsLiteralCString(
+            "SELECT 1 "
+            "FROM moz_bookmarks "
+            "WHERE dateAdded % 1000 > 0 OR lastModified % 1000 > 0 LIMIT 1"),
+        getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found unrounded dates!");
+
+    // Sanity check url_hash
+    rv = mMainConn->CreateStatement(
+        "SELECT 1 FROM moz_places WHERE url_hash = 0"_ns, getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found a place without a hash!");
+
+    // Sanity check unique urls
+    rv = mMainConn->CreateStatement(
+        nsLiteralCString(
+            "SELECT 1 FROM moz_places GROUP BY url HAVING count(*) > 1 "),
+        getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found a duplicate url!");
+
+    // Sanity check NULL urls
+    rv = mMainConn->CreateStatement(
+        "SELECT 1 FROM moz_places WHERE url ISNULL "_ns, getter_AddRefs(stmt));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = stmt->ExecuteStep(&hasResult);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    MOZ_ASSERT(!hasResult, "Found a NULL url!");
+  }
+#endif
+
+  mMainThreadStatements.FinalizeStatements();
+  mMainThreadAsyncStatements.FinalizeStatements();
+
+  RefPtr<FinalizeStatementCacheProxy<mozIStorageStatement>> event =
+      new FinalizeStatementCacheProxy<mozIStorageStatement>(
+          mAsyncThreadStatements, NS_ISUPPORTS_CAST(nsIObserver*, this));
+  DispatchToAsyncThread(event);
+
+  mClosed = true;
+
+  // Execute PRAGMA optimized as last step, this will ensure proper database
+  // performance across restarts.
+  nsCOMPtr<mozIStoragePendingStatement> ps;
+  MOZ_ALWAYS_SUCCEEDS(mMainConn->ExecuteSimpleSQLAsync(
+      "PRAGMA optimize(0x02)"_ns, nullptr, getter_AddRefs(ps)));
+
+  if (NS_FAILED(mMainConn->AsyncClose(connectionShutdown))) {
+    mozilla::Unused << connectionShutdown->Complete(NS_ERROR_UNEXPECTED,
+                                                    nullptr);
+  }
+  mMainConn = nullptr;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+Database::Observe(nsISupports* aSubject, const char* aTopic,
+                  const char16_t* aData) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (strcmp(aTopic, TOPIC_PROFILE_CHANGE_TEARDOWN) == 0) {
+    // Tests simulating shutdown may cause multiple notifications.
+    if (PlacesShutdownBlocker::sIsStarted) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIObserverService> os = services::GetObserverService();
+    NS_ENSURE_STATE(os);
+
+    // If shutdown happens in the same mainthread loop as init, observers could
+    // handle the places-init-complete notification after xpcom-shutdown, when
+    // the connection does not exist anymore.  Removing those observers would
+    // be less expensive but may cause their RemoveObserver calls to throw.
+    // Thus notify the topic now, so they stop listening for it.
+    nsCOMPtr<nsISimpleEnumerator> e;
+    if (NS_SUCCEEDED(os->EnumerateObservers(TOPIC_PLACES_INIT_COMPLETE,
+                                            getter_AddRefs(e))) &&
+        e) {
+      bool hasMore = false;
+      while (NS_SUCCEEDED(e->HasMoreElements(&hasMore)) && hasMore) {
+        nsCOMPtr<nsISupports> supports;
+        if (NS_SUCCEEDED(e->GetNext(getter_AddRefs(supports)))) {
+          nsCOMPtr<nsIObserver> observer = do_QueryInterface(supports);
+          (void)observer->Observe(observer, TOPIC_PLACES_INIT_COMPLETE,
+                                  nullptr);
+        }
+      }
+    }
+
+    // Notify all Places users that we are about to shutdown.
+    (void)os->NotifyObservers(nullptr, TOPIC_PLACES_SHUTDOWN, nullptr);
+  } else if (strcmp(aTopic, TOPIC_SIMULATE_PLACES_SHUTDOWN) == 0) {
+    // This notification is (and must be) only used by tests that are trying
+    // to simulate Places shutdown out of the normal shutdown path.
+
+    // Tests simulating shutdown may cause re-entrance.
+    if (PlacesShutdownBlocker::sIsStarted) {
+      return NS_OK;
+    }
+
+    // We are simulating a shutdown, so invoke the shutdown blockers,
+    // wait for them, then proceed with connection shutdown.
+    // Since we are already going through shutdown, but it's not the real one,
+    // we won't need to block the real one anymore, so we can unblock it.
+    {
+      nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase =
+          GetProfileChangeTeardownPhase();
+      if (shutdownPhase) {
+        shutdownPhase->RemoveBlocker(mClientsShutdown.get());
+      }
+      (void)mClientsShutdown->BlockShutdown(nullptr);
+    }
+
+    // Spin the events loop until the clients are done.
+    // Note, this is just for tests, specifically test_clearHistory_shutdown.js
+    SpinEventLoopUntil("places:Database::Observe(SIMULATE_PLACES_SHUTDOWN)"_ns,
+                       [&]() {
+                         return mClientsShutdown->State() ==
+                                PlacesShutdownBlocker::States::RECEIVED_DONE;
+                       });
+
+    {
+      nsCOMPtr<nsIAsyncShutdownClient> shutdownPhase =
+          GetProfileBeforeChangePhase();
+      if (shutdownPhase) {
+        shutdownPhase->RemoveBlocker(mConnectionShutdown.get());
+      }
+      (void)mConnectionShutdown->BlockShutdown(nullptr);
+    }
+  }
+  return NS_OK;
+}
+
+}  // namespace mozilla::places
diff --git a/toolkit/components/places/Database.h b/toolkit/components/places/Database.h
new file mode 100644
index 0000000000..1798f73eec
--- /dev/null
+++ b/toolkit/components/places/Database.h
@@ -0,0 +1,375 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_Database_h_
+#define mozilla_places_Database_h_
+
+#include "MainThreadUtils.h"
+#include "nsWeakReference.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIObserver.h"
+#include "mozilla/storage.h"
+#include "mozilla/storage/StatementCache.h"
+#include "mozilla/Attributes.h"
+#include "nsIEventTarget.h"
+#include "Shutdown.h"
+#include "nsCategoryCache.h"
+
+// Fired after Places inited.
+#define TOPIC_PLACES_INIT_COMPLETE "places-init-complete"
+// This topic is received when the profile is about to be lost.  Places does
+// initial shutdown work and notifies TOPIC_PLACES_SHUTDOWN to all listeners.
+// Any shutdown work that requires the Places APIs should happen here.
+#define TOPIC_PROFILE_CHANGE_TEARDOWN "profile-change-teardown"
+// Fired when Places is shutting down.  Any code should stop accessing Places
+// APIs after this notification.  If you need to listen for Places shutdown
+// you should only use this notification, next ones are intended only for
+// internal Places use.
+#define TOPIC_PLACES_SHUTDOWN "places-shutdown"
+// Fired when the connection has gone, nothing will work from now on.
+#define TOPIC_PLACES_CONNECTION_CLOSED "places-connection-closed"
+
+// Simulate profile-before-change. This topic may only be used by
+// calling `observe` directly on the database. Used for testing only.
+#define TOPIC_SIMULATE_PLACES_SHUTDOWN "test-simulate-places-shutdown"
+
+class mozIStorageService;
+class nsIAsyncShutdownClient;
+class nsIRunnable;
+
+namespace mozilla::places {
+
+enum JournalMode {
+  // Default SQLite journal mode.
+  JOURNAL_DELETE = 0
+  // Can reduce fsyncs on Linux when journal is deleted (See bug 460315).
+  // We fallback to this mode when WAL is unavailable.
+  ,
+  JOURNAL_TRUNCATE
+  // Unsafe in case of crashes on database swap or low memory.
+  ,
+  JOURNAL_MEMORY
+  // Can reduce number of fsyncs.  We try to use this mode by default.
+  ,
+  JOURNAL_WAL
+};
+
+class ClientsShutdownBlocker;
+class ConnectionShutdownBlocker;
+
+class Database final : public nsIObserver, public nsSupportsWeakReference {
+  using StatementCache = mozilla::storage::StatementCache<mozIStorageStatement>;
+  using AsyncStatementCache =
+      mozilla::storage::StatementCache<mozIStorageAsyncStatement>;
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  Database();
+
+  /**
+   * Initializes the database connection and the schema.
+   * In case of corruption the database is copied to a backup file and replaced.
+   */
+  nsresult Init();
+
+  /**
+   * The AsyncShutdown client used by clients of this API to be informed of
+   * shutdown.
+   */
+  already_AddRefed<nsIAsyncShutdownClient> GetClientsShutdown();
+
+  /**
+   * The AsyncShutdown client used by clients of this API to be informed of
+   * connection shutdown.
+   */
+  already_AddRefed<nsIAsyncShutdownClient> GetConnectionShutdown();
+
+  /**
+   * Getter to use when instantiating the class.
+   *
+   * @return Singleton instance of this class.
+   */
+  static already_AddRefed<Database> GetDatabase();
+
+  /**
+   * Actually initialized the connection on first need.
+   */
+  nsresult EnsureConnection();
+
+  /**
+   * Notifies that the connection has been initialized.
+   */
+  nsresult NotifyConnectionInitalized();
+
+  /**
+   * Returns last known database status.
+   *
+   * @return one of the nsINavHistoryService::DATABASE_STATUS_* constants.
+   */
+  uint16_t GetDatabaseStatus() {
+    mozilla::Unused << EnsureConnection();
+    return mDatabaseStatus;
+  }
+
+  /**
+   * Returns a pointer to the storage connection.
+   *
+   * @return The connection handle.
+   */
+  mozIStorageConnection* MainConn() {
+    mozilla::Unused << EnsureConnection();
+    return mMainConn;
+  }
+
+  /**
+   * Dispatches a runnable to the connection async thread, to be serialized
+   * with async statements.
+   *
+   * @param aEvent
+   *        The runnable to be dispatched.
+   */
+  void DispatchToAsyncThread(nsIRunnable* aEvent) {
+    if (mClosed || NS_FAILED(EnsureConnection())) {
+      return;
+    }
+    nsCOMPtr<nsIEventTarget> target = do_GetInterface(mMainConn);
+    if (target) {
+      (void)target->Dispatch(aEvent, NS_DISPATCH_NORMAL);
+    }
+  }
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Statements Getters.
+
+  /**
+   * Gets a cached synchronous statement.
+   *
+   * @param aQuery
+   *        SQL query literal.
+   * @return The cached statement.
+   * @note Always null check the result.
+   * @note Always use a scoper to reset the statement.
+   */
+  template <int N>
+  already_AddRefed<mozIStorageStatement> GetStatement(const char (&aQuery)[N]) {
+    nsDependentCString query(aQuery, N - 1);
+    return GetStatement(query);
+  }
+
+  /**
+   * Gets a cached synchronous statement.
+   *
+   * @param aQuery
+   *        nsCString of SQL query.
+   * @return The cached statement.
+   * @note Always null check the result.
+   * @note Always use a scoper to reset the statement.
+   */
+  already_AddRefed<mozIStorageStatement> GetStatement(const nsACString& aQuery);
+
+  /**
+   * Gets a cached asynchronous statement.
+   *
+   * @param aQuery
+   *        SQL query literal.
+   * @return The cached statement.
+   * @note Always null check the result.
+   * @note AsyncStatements are automatically reset on execution.
+   */
+  template <int N>
+  already_AddRefed<mozIStorageAsyncStatement> GetAsyncStatement(
+      const char (&aQuery)[N]) {
+    nsDependentCString query(aQuery, N - 1);
+    return GetAsyncStatement(query);
+  }
+
+  /**
+   * Gets a cached asynchronous statement.
+   *
+   * @param aQuery
+   *        nsCString of SQL query.
+   * @return The cached statement.
+   * @note Always null check the result.
+   * @note AsyncStatements are automatically reset on execution.
+   */
+  already_AddRefed<mozIStorageAsyncStatement> GetAsyncStatement(
+      const nsACString& aQuery);
+
+  int64_t GetTagsFolderId() {
+    mozilla::Unused << EnsureConnection();
+    return mTagsRootId;
+  }
+
+ protected:
+  /**
+   * Finalizes the cached statements and closes the database connection.
+   * A TOPIC_PLACES_CONNECTION_CLOSED notification is fired when done.
+   */
+  void Shutdown();
+
+  /**
+   * Ensure the favicons database file exists.
+   *
+   * @param aStorage
+   *        mozStorage service instance.
+   */
+  nsresult EnsureFaviconsDatabaseAttached(
+      const nsCOMPtr<mozIStorageService>& aStorage);
+
+  /**
+   * Creates a database backup and replaces the original file with a new
+   * one.
+   *
+   * @param aStorage
+   *        mozStorage service instance.
+   * @param aDbfilename
+   *        the database file name to replace.
+   * @param aTryToClone
+   *        whether we should try to clone a corrupt database.
+   * @param aReopenConnection
+   *        whether we should open a new connection to the replaced database.
+   */
+  nsresult BackupAndReplaceDatabaseFile(nsCOMPtr<mozIStorageService>& aStorage,
+                                        const nsString& aDbFilename,
+                                        bool aTryToClone,
+                                        bool aReopenConnection);
+
+  /**
+   * Tries to recover tables and their contents from a corrupt database.
+   *
+   * @param aStorage
+   *        mozStorage service instance.
+   * @param aDatabaseFile
+   *        nsIFile pointing to the places.sqlite file considered corrupt.
+   */
+  nsresult TryToCloneTablesFromCorruptDatabase(
+      const nsCOMPtr<mozIStorageService>& aStorage,
+      const nsCOMPtr<nsIFile>& aDatabaseFile);
+
+  /**
+   * Set up the connection environment through PRAGMAs.
+   * Will return NS_ERROR_FILE_CORRUPTED if any critical setting fails.
+   *
+   * @param aStorage
+   *        mozStorage service instance.
+   */
+  nsresult SetupDatabaseConnection(nsCOMPtr<mozIStorageService>& aStorage);
+
+  /**
+   * Initializes the schema.  This performs any necessary migrations for the
+   * database.  All migration is done inside a transaction that is rolled back
+   * if any error occurs.
+   * @param aDatabaseMigrated
+   *        Whether a schema upgrade happened.
+   */
+  nsresult InitSchema(bool* aDatabaseMigrated);
+
+  /**
+   * Checks the root bookmark folders are present, and saves the IDs for them.
+   */
+  nsresult CheckRoots();
+
+  /**
+   * Creates bookmark roots in a new DB.
+   */
+  nsresult EnsureBookmarkRoots(const int32_t startPosition,
+                               bool shouldReparentRoots);
+
+  /**
+   * Initializes additionale SQLite functions, defined in SQLFunctions.h
+   */
+  nsresult InitFunctions();
+
+  /**
+   * Initializes temp entities, like triggers, tables, views...
+   */
+  nsresult InitTempEntities();
+
+  /**
+   * Helpers used by schema upgrades.
+   * When adding a new function remember to bump up the schema version in
+   * nsINavHistoryService.
+   */
+  nsresult MigrateV53Up();
+  nsresult MigrateV54Up();
+  nsresult MigrateV55Up();
+  nsresult MigrateV56Up();
+  nsresult MigrateV57Up();
+  nsresult MigrateV60Up();
+  nsresult MigrateV61Up();
+  nsresult MigrateV67Up();
+  nsresult MigrateV69Up();
+  nsresult MigrateV70Up();
+  nsresult MigrateV71Up();
+  nsresult MigrateV72Up();
+  nsresult MigrateV73Up();
+  nsresult MigrateV74Up();
+  nsresult MigrateV75Up();
+
+  nsresult UpdateBookmarkRootTitles();
+
+  friend class ConnectionShutdownBlocker;
+
+  int64_t CreateMobileRoot();
+
+ private:
+  ~Database();
+
+  /**
+   * Singleton getter, invoked by class instantiation.
+   */
+  static already_AddRefed<Database> GetSingleton();
+
+  static Database* gDatabase;
+
+  nsCOMPtr<mozIStorageConnection> mMainConn;
+
+  mutable StatementCache mMainThreadStatements;
+  mutable AsyncStatementCache mMainThreadAsyncStatements;
+  mutable StatementCache mAsyncThreadStatements;
+
+  int32_t mDBPageSize;
+  uint16_t mDatabaseStatus;
+  bool mClosed;
+
+  /**
+   * Phases for shutting down the Database.
+   * See Shutdown.h for further details about the shutdown procedure.
+   */
+  already_AddRefed<nsIAsyncShutdownClient> GetProfileChangeTeardownPhase();
+  already_AddRefed<nsIAsyncShutdownClient> GetProfileBeforeChangePhase();
+
+  /**
+   * Blockers in charge of waiting for the Places clients and then shutting
+   * down the mozStorage connection.
+   * See Shutdown.h for further details about the shutdown procedure.
+   *
+   * Cycles with these are broken in `Shutdown()`.
+   */
+  RefPtr<ClientsShutdownBlocker> mClientsShutdown;
+  RefPtr<ConnectionShutdownBlocker> mConnectionShutdown;
+
+  // Maximum length of a stored url.
+  // For performance reasons we don't store very long urls in history, since
+  // they are slower to search through and cause abnormal database growth,
+  // affecting the awesomebar fetch time.
+  uint32_t mMaxUrlLength;
+
+  // Used to initialize components on places startup.
+  nsCategoryCache<nsIObserver> mCacheObservers;
+
+  // Used to cache the places folder Ids when the connection is started.
+  int64_t mRootId;
+  int64_t mMenuRootId;
+  int64_t mTagsRootId;
+  int64_t mUnfiledRootId;
+  int64_t mToolbarRootId;
+  int64_t mMobileRootId;
+};
+
+}  // namespace mozilla::places
+
+#endif  // mozilla_places_Database_h_
diff --git a/toolkit/components/places/ExtensionSearchHandler.sys.mjs b/toolkit/components/places/ExtensionSearchHandler.sys.mjs
new file mode 100644
index 0000000000..a04e40b6c6
--- /dev/null
+++ b/toolkit/components/places/ExtensionSearchHandler.sys.mjs
@@ -0,0 +1,336 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Used to keep track of all of the registered keywords, where each keyword is
+// mapped to a KeywordInfo instance.
+let gKeywordMap = new Map();
+
+// Used to keep track of the active input session.
+let gActiveInputSession = null;
+
+// Used to keep track of who has control over the active suggestion callback
+// so older callbacks can be ignored. The callback ID should increment whenever
+// the input changes or the input session ends.
+let gCurrentCallbackID = 0;
+
+// Handles keeping track of information associated to the registered keyword.
+class KeywordInfo {
+  constructor(extension, description) {
+    this._extension = extension;
+    this._description = description;
+  }
+
+  get description() {
+    return this._description;
+  }
+
+  set description(desc) {
+    this._description = desc;
+  }
+
+  get extension() {
+    return this._extension;
+  }
+}
+
+// Responsible for handling communication between the extension and the urlbar.
+class InputSession {
+  constructor(keyword, extension) {
+    this._keyword = keyword;
+    this._extension = extension;
+    this._suggestionsCallback = null;
+    this._searchFinishedCallback = null;
+  }
+
+  get keyword() {
+    return this._keyword;
+  }
+
+  addSuggestions(suggestions) {
+    if (this._suggestionsCallback) {
+      this._suggestionsCallback(suggestions);
+    }
+  }
+
+  start(eventName) {
+    this._extension.emit(eventName);
+  }
+
+  update(eventName, text, suggestionsCallback, searchFinishedCallback) {
+    // Check to see if an existing input session needs to be ended first.
+    if (this._searchFinishedCallback) {
+      this._searchFinishedCallback();
+    }
+    this._searchFinishedCallback = searchFinishedCallback;
+    this._suggestionsCallback = suggestionsCallback;
+    this._extension.emit(eventName, text, ++gCurrentCallbackID);
+  }
+
+  cancel(eventName) {
+    if (this._searchFinishedCallback) {
+      this._searchFinishedCallback();
+      this._searchFinishedCallback = null;
+      this._suggestionsCallback = null;
+    }
+    this._extension.emit(eventName);
+  }
+
+  end(eventName, text, disposition) {
+    if (this._searchFinishedCallback) {
+      this._searchFinishedCallback();
+      this._searchFinishedCallback = null;
+      this._suggestionsCallback = null;
+    }
+    this._extension.emit(eventName, text, disposition);
+  }
+}
+
+export var ExtensionSearchHandler = Object.freeze({
+  MSG_INPUT_STARTED: "webext-omnibox-input-started",
+  MSG_INPUT_CHANGED: "webext-omnibox-input-changed",
+  MSG_INPUT_ENTERED: "webext-omnibox-input-entered",
+  MSG_INPUT_CANCELLED: "webext-omnibox-input-cancelled",
+  MSG_INPUT_DELETED: "webext-omnibox-input-deleted",
+
+  /**
+   * Registers a keyword.
+   *
+   * @param {string} keyword The keyword to register.
+   * @param {Extension} extension The extension registering the keyword.
+   */
+  registerKeyword(keyword, extension) {
+    if (gKeywordMap.has(keyword)) {
+      throw new Error(
+        `The keyword provided is already registered: "${keyword}"`
+      );
+    }
+    gKeywordMap.set(keyword, new KeywordInfo(extension, extension.name));
+  },
+
+  /**
+   * Unregisters a keyword.
+   *
+   * @param {string} keyword The keyword to unregister.
+   */
+  unregisterKeyword(keyword) {
+    if (!gKeywordMap.has(keyword)) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+    gActiveInputSession = null;
+    gKeywordMap.delete(keyword);
+  },
+
+  /**
+   * Checks if a keyword is registered.
+   *
+   * @param {string} keyword The word to check.
+   * @return {boolean} true if the word is a registered keyword.
+   */
+  isKeywordRegistered(keyword) {
+    return gKeywordMap.has(keyword);
+  },
+
+  /**
+   * @return {boolean} true if there is an active input session.
+   */
+  hasActiveInputSession() {
+    return gActiveInputSession != null;
+  },
+
+  /**
+   * @param {string} keyword The keyword to look up.
+   * @return {string} the description to use for the heuristic result.
+   */
+  getDescription(keyword) {
+    if (!gKeywordMap.has(keyword)) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+    return gKeywordMap.get(keyword).description;
+  },
+
+  /**
+   * Sets the default suggestion for the registered keyword. The suggestion's
+   * description will be used for the comment in the heuristic result.
+   *
+   * @param {string} keyword The keyword.
+   * @param {string} description The description to use for the heuristic result.
+   */
+  setDefaultSuggestion(keyword, { description }) {
+    if (!gKeywordMap.has(keyword)) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+    gKeywordMap.get(keyword).description = description;
+  },
+
+  /**
+   * Adds suggestions for the registered keyword. This function will throw if
+   * the keyword provided is not registered or active, or if the callback ID
+   * provided is no longer equal to the active callback ID.
+   *
+   * @param {string} keyword The keyword.
+   * @param {integer} id The ID of the suggestion callback.
+   * @param {Array<Object>} suggestions An array of suggestions to provide to the urlbar.
+   */
+  addSuggestions(keyword, id, suggestions) {
+    if (!gKeywordMap.has(keyword)) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+
+    if (!gActiveInputSession || gActiveInputSession.keyword != keyword) {
+      throw new Error(
+        `The keyword provided is not apart of an active input session: "${keyword}"`
+      );
+    }
+
+    if (id != gCurrentCallbackID) {
+      throw new Error(
+        `The callback is no longer active for the keyword provided: "${keyword}"`
+      );
+    }
+
+    gActiveInputSession.addSuggestions(suggestions);
+  },
+
+  /**
+   * Called when the input in the urlbar begins with `<keyword><space>`.
+   *
+   * If the keyword is inactive, MSG_INPUT_STARTED is emitted and the
+   * keyword is marked as active. If the keyword is followed by any text,
+   * MSG_INPUT_CHANGED is fired with the current callback ID that can be
+   * used to provide suggestions to the urlbar while the callback ID is active.
+   * The callback is invalidated when either the input changes or the urlbar blurs.
+   *
+   * @param {object} data An object that contains
+   *                 {string} keyword The keyword to handle.
+   *                 {string} text The search text in the urlbar.
+   *                 {boolean} inPrivateWindow privateness of window search
+   *                           is occuring in.
+   * @param {Function} callback The callback used to provide search suggestions.
+   * @return {Promise} promise that resolves when the current search is complete.
+   */
+  handleSearch(data, callback) {
+    let { keyword, text } = data;
+    let keywordInfo = gKeywordMap.get(keyword);
+    if (!keywordInfo) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+
+    let { extension } = keywordInfo;
+    if (data.inPrivateWindow && !extension.privateBrowsingAllowed) {
+      return Promise.resolve(false);
+    }
+
+    if (gActiveInputSession && gActiveInputSession.keyword != keyword) {
+      throw new Error("A different input session is already ongoing");
+    }
+
+    if (!text || !text.startsWith(`${keyword} `)) {
+      throw new Error(`The text provided must start with: "${keyword} "`);
+    }
+
+    if (!callback) {
+      throw new Error("A callback must be provided");
+    }
+
+    // The search text in the urlbar currently starts with <keyword><space>, and
+    // we only want the text that follows.
+    text = text.substring(keyword.length + 1);
+
+    // We fire MSG_INPUT_STARTED once we have <keyword><space>, and only fire
+    // MSG_INPUT_CHANGED when we have text to process. This is different from Chrome's
+    // behavior, which always fires MSG_INPUT_STARTED right before MSG_INPUT_CHANGED
+    // first fires, but this is a bug in Chrome according to https://crbug.com/258911.
+    if (!gActiveInputSession) {
+      gActiveInputSession = new InputSession(keyword, extension);
+      gActiveInputSession.start(this.MSG_INPUT_STARTED);
+
+      // Resolve early if there is no text to process. There can be text to process when
+      // the input starts if the user copy/pastes the text into the urlbar.
+      if (!text.length) {
+        return Promise.resolve();
+      }
+    }
+
+    return new Promise(resolve => {
+      gActiveInputSession.update(
+        this.MSG_INPUT_CHANGED,
+        text,
+        callback,
+        resolve
+      );
+    });
+  },
+
+  /**
+   * Called when the user clicks on a suggestion that was added by
+   * an extension. MSG_INPUT_ENTERED is emitted to the extension with
+   * the keyword, the current search string, and info about how the
+   * the search should be handled. This ends the active input session.
+   *
+   * @param {string} keyword The keyword associated to the suggestion.
+   * @param {string} text The search text in the urlbar.
+   * @param {string} where How the page should be opened. Accepted values are:
+   *    "current": open the page in the same tab.
+   *    "tab": open the page in a new foreground tab.
+   *    "tabshifted": open the page in a new background tab.
+   */
+  handleInputEntered(keyword, text, where) {
+    if (!gKeywordMap.has(keyword)) {
+      throw new Error(`The keyword provided is not registered: "${keyword}"`);
+    }
+
+    if (!gActiveInputSession) {
+      throw new Error("There is no active input session");
+    }
+
+    if (gActiveInputSession && gActiveInputSession.keyword != keyword) {
+      throw new Error("A different input session is already ongoing");
+    }
+
+    if (!text || !text.startsWith(`${keyword} `)) {
+      throw new Error(`The text provided must start with: "${keyword} "`);
+    }
+
+    let dispositionMap = {
+      current: "currentTab",
+      tab: "newForegroundTab",
+      tabshifted: "newBackgroundTab",
+    };
+    let disposition = dispositionMap[where];
+
+    if (!disposition) {
+      throw new Error(`Invalid "where" argument: ${where}`);
+    }
+
+    // The search text in the urlbar currently starts with <keyword><space>, and
+    // we only want to send the text that follows.
+    text = text.substring(keyword.length + 1);
+
+    gActiveInputSession.end(this.MSG_INPUT_ENTERED, text, disposition);
+    gActiveInputSession = null;
+  },
+
+  /**
+   * Called when the user deletes a suggestion that was added by
+   * an extension. MSG_INPUT_DELETED is emitted to the extension with
+   * the description of the suggestion that was deleted.
+   *
+   * @param {string} text The description of the suggestion.
+   */
+  handleInputDeleted(text) {
+    return gActiveInputSession.update(this.MSG_INPUT_DELETED, text);
+  },
+
+  /**
+   * If the user has ended the keyword input session without accepting the input,
+   * MSG_INPUT_CANCELLED is emitted and the input session is ended.
+   */
+  handleInputCancelled() {
+    if (!gActiveInputSession) {
+      throw new Error("There is no active input session");
+    }
+    gActiveInputSession.cancel(this.MSG_INPUT_CANCELLED);
+    gActiveInputSession = null;
+  },
+});
diff --git a/toolkit/components/places/FaviconHelpers.cpp b/toolkit/components/places/FaviconHelpers.cpp
new file mode 100644
index 0000000000..1c565a3de1
--- /dev/null
+++ b/toolkit/components/places/FaviconHelpers.cpp
@@ -0,0 +1,1261 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FaviconHelpers.h"
+
+#include "nsICacheEntry.h"
+#include "nsICachingChannel.h"
+#include "nsIClassOfService.h"
+#include "nsIAsyncVerifyRedirectCallback.h"
+#include "nsIHttpChannel.h"
+#include "nsIPrincipal.h"
+
+#include "nsComponentManagerUtils.h"
+#include "nsNavHistory.h"
+#include "nsFaviconService.h"
+
+#include "mozilla/dom/PlacesFavicon.h"
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/storage.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/StaticPrefs_network.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsStreamUtils.h"
+#include "nsStringStream.h"
+#include "nsIPrivateBrowsingChannel.h"
+#include "nsISupportsPriority.h"
+#include <algorithm>
+#include <deque>
+#include "mozilla/gfx/2D.h"
+#include "imgIContainer.h"
+#include "ImageOps.h"
+#include "imgIEncoder.h"
+
+using namespace mozilla;
+using namespace mozilla::places;
+using namespace mozilla::storage;
+
+namespace mozilla {
+namespace places {
+
+namespace {
+
+/**
+ * Fetches information about a page from the database.
+ *
+ * @param aDB
+ *        Database connection to history tables.
+ * @param _page
+ *        Page that should be fetched.
+ */
+nsresult FetchPageInfo(const RefPtr<Database>& aDB, PageData& _page) {
+  MOZ_ASSERT(_page.spec.Length(), "Must have a non-empty spec!");
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // The subquery finds the bookmarked uri we want to set the icon for,
+  // walking up redirects.
+  nsCString query = nsPrintfCString(
+      "SELECT h.id, pi.id, h.guid, ( "
+      "WITH RECURSIVE "
+      "destinations(visit_type, from_visit, place_id, rev_host, bm) AS ( "
+      "SELECT v.visit_type, v.from_visit, p.id, p.rev_host, b.id "
+      "FROM moz_places p  "
+      "LEFT JOIN moz_historyvisits v ON v.place_id = p.id  "
+      "LEFT JOIN moz_bookmarks b ON b.fk = p.id "
+      "WHERE p.id = h.id "
+      "UNION "
+      "SELECT src.visit_type, src.from_visit, src.place_id, p.rev_host, b.id "
+      "FROM moz_places p "
+      "JOIN moz_historyvisits src ON src.place_id = p.id "
+      "JOIN destinations dest ON dest.from_visit = src.id AND dest.visit_type "
+      "IN (%d, %d) "
+      "LEFT JOIN moz_bookmarks b ON b.fk = src.place_id "
+      "WHERE instr(p.rev_host, dest.rev_host) = 1 "
+      "OR instr(dest.rev_host, p.rev_host) = 1 "
+      ") "
+      "SELECT url "
+      "FROM moz_places p "
+      "JOIN destinations r ON r.place_id = p.id "
+      "WHERE bm NOTNULL "
+      "LIMIT 1 "
+      "), fixup_url(get_unreversed_host(h.rev_host)) AS host "
+      "FROM moz_places h "
+      "LEFT JOIN moz_pages_w_icons pi ON page_url_hash = hash(:page_url) AND "
+      "page_url = :page_url "
+      "WHERE h.url_hash = hash(:page_url) AND h.url = :page_url",
+      nsINavHistoryService::TRANSITION_REDIRECT_PERMANENT,
+      nsINavHistoryService::TRANSITION_REDIRECT_TEMPORARY);
+
+  nsCOMPtr<mozIStorageStatement> stmt = aDB->GetStatement(query);
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = URIBinder::Bind(stmt, "page_url"_ns, _page.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!hasResult) {
+    // The page does not exist.
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  rv = stmt->GetInt64(0, &_page.placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // May be null, and in such a case this will be 0.
+  _page.id = stmt->AsInt64(1);
+  rv = stmt->GetUTF8String(2, _page.guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Bookmarked url can be nullptr.
+  bool isNull;
+  rv = stmt->GetIsNull(3, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // The page could not be bookmarked.
+  if (!isNull) {
+    rv = stmt->GetUTF8String(3, _page.bookmarkedSpec);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (_page.host.IsEmpty()) {
+    rv = stmt->GetUTF8String(4, _page.host);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (!_page.canAddToHistory) {
+    // Either history is disabled or the scheme is not supported.  In such a
+    // case we want to update the icon only if the page is bookmarked.
+
+    if (_page.bookmarkedSpec.IsEmpty()) {
+      // The page is not bookmarked.  Since updating the icon with a disabled
+      // history would be a privacy leak, bail out as if the page did not exist.
+      return NS_ERROR_NOT_AVAILABLE;
+    } else {
+      // The page, or a redirect to it, is bookmarked.  If the bookmarked spec
+      // is different from the requested one, use it.
+      if (!_page.bookmarkedSpec.Equals(_page.spec)) {
+        _page.spec = _page.bookmarkedSpec;
+        rv = FetchPageInfo(aDB, _page);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Stores information about an icon in the database.
+ *
+ * @param aDB
+ *        Database connection to history tables.
+ * @param aIcon
+ *        Icon that should be stored.
+ * @param aMustReplace
+ *        If set to true, the function will bail out with NS_ERROR_NOT_AVAILABLE
+ *        if it can't find a previous stored icon to replace.
+ * @note Should be wrapped in a transaction.
+ */
+nsresult SetIconInfo(const RefPtr<Database>& aDB, IconData& aIcon,
+                     bool aMustReplace = false) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aIcon.payloads.Length() > 0);
+  MOZ_ASSERT(!aIcon.spec.IsEmpty());
+  MOZ_ASSERT(aIcon.expiration > 0);
+
+  // There are multiple cases possible at this point:
+  //   1. We must insert some payloads and no payloads exist in the table. This
+  //      would be a straight INSERT.
+  //   2. The table contains the same number of payloads we are inserting. This
+  //      would be a straight UPDATE.
+  //   3. The table contains more payloads than we are inserting. This would be
+  //      an UPDATE and a DELETE.
+  //   4. The table contains less payloads than we are inserting. This would be
+  //      an UPDATE and an INSERT.
+  // We can't just remove all the old entries and insert the new ones, cause
+  // we'd lose the referential integrity with pages.  For the same reason we
+  // cannot use INSERT OR REPLACE, since it's implemented as DELETE AND INSERT.
+  // Thus, we follow this strategy:
+  //   * SELECT all existing icon ids
+  //   * For each payload, either UPDATE OR INSERT reusing icon ids.
+  //   * If any previous icon ids is leftover, DELETE it.
+
+  nsCOMPtr<mozIStorageStatement> selectStmt = aDB->GetStatement(
+      "SELECT id FROM moz_icons "
+      "WHERE fixed_icon_url_hash = hash(fixup_url(:url)) "
+      "AND icon_url = :url ");
+  NS_ENSURE_STATE(selectStmt);
+  mozStorageStatementScoper scoper(selectStmt);
+  nsresult rv = URIBinder::Bind(selectStmt, "url"_ns, aIcon.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  std::deque<int64_t> ids;
+  bool hasResult = false;
+  while (NS_SUCCEEDED(selectStmt->ExecuteStep(&hasResult)) && hasResult) {
+    int64_t id = selectStmt->AsInt64(0);
+    MOZ_ASSERT(id > 0);
+    ids.push_back(id);
+  }
+  if (aMustReplace && ids.empty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsCOMPtr<mozIStorageStatement> insertStmt = aDB->GetStatement(
+      "INSERT INTO moz_icons "
+      "(icon_url, fixed_icon_url_hash, width, root, expire_ms, data) "
+      "VALUES (:url, hash(fixup_url(:url)), :width, :root, :expire, :data) ");
+  NS_ENSURE_STATE(insertStmt);
+  // ReplaceFaviconData may replace data for an already existing icon, and in
+  // that case it won't have the page uri at hand, thus it can't tell if the
+  // icon is a root icon or not. For that reason, never overwrite a root = 1.
+  nsCOMPtr<mozIStorageStatement> updateStmt = aDB->GetStatement(
+      "UPDATE moz_icons SET width = :width, "
+      "expire_ms = :expire, "
+      "data = :data, "
+      "root = (root  OR :root) "
+      "WHERE id = :id ");
+  NS_ENSURE_STATE(updateStmt);
+
+  for (auto& payload : aIcon.payloads) {
+    // Sanity checks.
+    MOZ_ASSERT(payload.mimeType.EqualsLiteral(PNG_MIME_TYPE) ||
+                   payload.mimeType.EqualsLiteral(SVG_MIME_TYPE),
+               "Only png and svg payloads are supported");
+    MOZ_ASSERT(!payload.mimeType.EqualsLiteral(SVG_MIME_TYPE) ||
+                   payload.width == UINT16_MAX,
+               "SVG payloads should have max width");
+    MOZ_ASSERT(payload.width > 0, "Payload should have a width");
+#ifdef DEBUG
+    // Done to ensure we fetch the id. See the MOZ_ASSERT below.
+    payload.id = 0;
+#endif
+    if (!ids.empty()) {
+      // Pop the first existing id for reuse.
+      int64_t id = ids.front();
+      ids.pop_front();
+      mozStorageStatementScoper scoper(updateStmt);
+      rv = updateStmt->BindInt64ByName("id"_ns, id);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = updateStmt->BindInt32ByName("width"_ns, payload.width);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = updateStmt->BindInt64ByName("expire"_ns, aIcon.expiration / 1000);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = updateStmt->BindInt32ByName("root"_ns, aIcon.rootIcon);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = updateStmt->BindBlobByName("data"_ns, TO_INTBUFFER(payload.data),
+                                      payload.data.Length());
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = updateStmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Set the new payload id.
+      payload.id = id;
+    } else {
+      // Insert a new entry.
+      mozStorageStatementScoper scoper(insertStmt);
+      rv = URIBinder::Bind(insertStmt, "url"_ns, aIcon.spec);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = insertStmt->BindInt32ByName("width"_ns, payload.width);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      rv = insertStmt->BindInt32ByName("root"_ns, aIcon.rootIcon);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = insertStmt->BindInt64ByName("expire"_ns, aIcon.expiration / 1000);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = insertStmt->BindBlobByName("data"_ns, TO_INTBUFFER(payload.data),
+                                      payload.data.Length());
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = insertStmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Set the new payload id.
+      payload.id = nsFaviconService::sLastInsertedIconId;
+    }
+    MOZ_ASSERT(payload.id > 0, "Payload should have an id");
+  }
+
+  if (!ids.empty()) {
+    // Remove any old leftover payload.
+    nsAutoCString sql("DELETE FROM moz_icons WHERE id IN (");
+    for (int64_t id : ids) {
+      sql.AppendInt(id);
+      sql.AppendLiteral(",");
+    }
+    sql.AppendLiteral(" 0)");  // Non-existing id to match the trailing comma.
+    nsCOMPtr<mozIStorageStatement> stmt = aDB->GetStatement(sql);
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Fetches information on a icon url from the database.
+ *
+ * @param aDBConn
+ *        Database connection to history tables.
+ * @param aPreferredWidth
+ *        The preferred size to fetch.
+ * @param _icon
+ *        Icon that should be fetched.
+ */
+nsresult FetchIconInfo(const RefPtr<Database>& aDB, uint16_t aPreferredWidth,
+                       IconData& _icon) {
+  MOZ_ASSERT(_icon.spec.Length(), "Must have a non-empty spec!");
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  if (_icon.status & ICON_STATUS_CACHED) {
+    // The icon data has already been set by ReplaceFaviconData.
+    return NS_OK;
+  }
+
+  nsCOMPtr<mozIStorageStatement> stmt = aDB->GetStatement(
+      "/* do not warn (bug no: not worth having a compound index) */ "
+      "SELECT id, expire_ms, data, width, root "
+      "FROM moz_icons "
+      "WHERE fixed_icon_url_hash = hash(fixup_url(:url)) "
+      "AND icon_url = :url "
+      "ORDER BY width DESC ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  DebugOnly<nsresult> rv = URIBinder::Bind(stmt, "url"_ns, _icon.spec);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+  bool hasResult = false;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    IconPayload payload;
+    rv = stmt->GetInt64(0, &payload.id);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+    // Expiration can be nullptr.
+    bool isNull;
+    rv = stmt->GetIsNull(1, &isNull);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    if (!isNull) {
+      int64_t expire_ms;
+      rv = stmt->GetInt64(1, &expire_ms);
+      MOZ_ASSERT(NS_SUCCEEDED(rv));
+      _icon.expiration = expire_ms * 1000;
+    }
+
+    uint8_t* data;
+    uint32_t dataLen = 0;
+    rv = stmt->GetBlob(2, &dataLen, &data);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    payload.data.Adopt(TO_CHARBUFFER(data), dataLen);
+
+    int32_t width;
+    rv = stmt->GetInt32(3, &width);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    payload.width = width;
+    if (payload.width == UINT16_MAX) {
+      payload.mimeType.AssignLiteral(SVG_MIME_TYPE);
+    } else {
+      payload.mimeType.AssignLiteral(PNG_MIME_TYPE);
+    }
+
+    int32_t rootIcon;
+    rv = stmt->GetInt32(4, &rootIcon);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    _icon.rootIcon = rootIcon;
+
+    if (aPreferredWidth == 0 || _icon.payloads.Length() == 0) {
+      _icon.payloads.AppendElement(payload);
+    } else if (payload.width >= aPreferredWidth) {
+      // Only retain the best matching payload.
+      _icon.payloads.ReplaceElementAt(0, payload);
+    } else {
+      break;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult FetchIconPerSpec(const RefPtr<Database>& aDB,
+                          const nsACString& aPageSpec,
+                          const nsACString& aPageHost, IconData& aIconData,
+                          uint16_t aPreferredWidth) {
+  MOZ_ASSERT(!aPageSpec.IsEmpty(), "Page spec must not be empty.");
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // This selects both associated and root domain icons, ordered by width,
+  // where an associated icon has priority over a root domain icon.
+  // Regardless, note that while this way we are far more efficient, we lost
+  // associations with root domain icons, so it's possible we'll return one
+  // for a specific size when an associated icon for that size doesn't exist.
+  nsCOMPtr<mozIStorageStatement> stmt = aDB->GetStatement(
+      "/* do not warn (bug no: not worth having a compound index) */ "
+      "SELECT width, icon_url, root "
+      "FROM moz_icons i "
+      "JOIN moz_icons_to_pages ON i.id = icon_id "
+      "JOIN moz_pages_w_icons p ON p.id = page_id "
+      "WHERE page_url_hash = hash(:url) AND page_url = :url "
+      "OR (:hash_idx AND page_url_hash = hash(substr(:url, 0, :hash_idx)) "
+      "AND page_url = substr(:url, 0, :hash_idx)) "
+      "UNION ALL "
+      "SELECT width, icon_url, root "
+      "FROM moz_icons i "
+      "WHERE fixed_icon_url_hash = hash(fixup_url(:host) || '/favicon.ico') "
+      "ORDER BY width DESC, root ASC");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = URIBinder::Bind(stmt, "url"_ns, aPageSpec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindUTF8StringByName("host"_ns, aPageHost);
+  NS_ENSURE_SUCCESS(rv, rv);
+  int32_t hashIdx = PromiseFlatCString(aPageSpec).RFind("#");
+  rv = stmt->BindInt32ByName("hash_idx"_ns, hashIdx + 1);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Return the biggest icon close to the preferred width. It may be bigger
+  // or smaller if the preferred width isn't found.
+  bool hasResult;
+  int32_t lastWidth = 0;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    int32_t width;
+    rv = stmt->GetInt32(0, &width);
+    if (lastWidth == width) {
+      // We already found an icon for this width. We always prefer the first
+      // icon found, because it's a non-root icon, per the root ASC ordering.
+      continue;
+    }
+    if (!aIconData.spec.IsEmpty() && width < aPreferredWidth) {
+      // We found the best match, or we already found a match so we don't need
+      // to fallback to the root domain icon.
+      break;
+    }
+    lastWidth = width;
+    rv = stmt->GetUTF8String(1, aIconData.spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Tries to compute the expiration time for a icon from the channel.
+ *
+ * @param aChannel
+ *        The network channel used to fetch the icon.
+ * @return a valid expiration value for the fetched icon.
+ */
+PRTime GetExpirationTimeFromChannel(nsIChannel* aChannel) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Attempt to get an expiration time from the cache.  If this fails, we'll
+  // make one up.
+  PRTime now = PR_Now();
+  PRTime expiration = -1;
+  nsCOMPtr<nsICachingChannel> cachingChannel = do_QueryInterface(aChannel);
+  if (cachingChannel) {
+    nsCOMPtr<nsISupports> cacheToken;
+    nsresult rv = cachingChannel->GetCacheToken(getter_AddRefs(cacheToken));
+    if (NS_SUCCEEDED(rv)) {
+      nsCOMPtr<nsICacheEntry> cacheEntry = do_QueryInterface(cacheToken);
+      uint32_t seconds;
+      rv = cacheEntry->GetExpirationTime(&seconds);
+      if (NS_SUCCEEDED(rv)) {
+        // Set the expiration, but make sure we honor our cap.
+        expiration = now + std::min((PRTime)seconds * PR_USEC_PER_SEC,
+                                    MAX_FAVICON_EXPIRATION);
+      }
+    }
+  }
+  // If we did not obtain a time from the cache, use the cap value.
+  return expiration < now + MIN_FAVICON_EXPIRATION
+             ? now + MAX_FAVICON_EXPIRATION
+             : expiration;
+}
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncFetchAndSetIconForPage
+
+NS_IMPL_ISUPPORTS_INHERITED(AsyncFetchAndSetIconForPage, Runnable,
+                            nsIStreamListener, nsIInterfaceRequestor,
+                            nsIChannelEventSink, mozIPlacesPendingOperation)
+
+AsyncFetchAndSetIconForPage::AsyncFetchAndSetIconForPage(
+    IconData& aIcon, PageData& aPage, bool aFaviconLoadPrivate,
+    nsIFaviconDataCallback* aCallback, nsIPrincipal* aLoadingPrincipal,
+    uint64_t aRequestContextID)
+    : Runnable("places::AsyncFetchAndSetIconForPage"),
+      mCallback(new nsMainThreadPtrHolder<nsIFaviconDataCallback>(
+          "AsyncFetchAndSetIconForPage::mCallback", aCallback)),
+      mIcon(aIcon),
+      mPage(aPage),
+      mFaviconLoadPrivate(aFaviconLoadPrivate),
+      mLoadingPrincipal(new nsMainThreadPtrHolder<nsIPrincipal>(
+          "AsyncFetchAndSetIconForPage::mLoadingPrincipal", aLoadingPrincipal)),
+      mCanceled(false),
+      mRequestContextID(aRequestContextID) {
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Try to fetch the icon from the database.
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  nsresult rv = FetchIconInfo(DB, 0, mIcon);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isInvalidIcon = !mIcon.payloads.Length() || PR_Now() > mIcon.expiration;
+  bool fetchIconFromNetwork =
+      mIcon.fetchMode == FETCH_ALWAYS ||
+      (mIcon.fetchMode == FETCH_IF_MISSING && isInvalidIcon);
+
+  // Check if we can associate the icon to this page.
+  rv = FetchPageInfo(DB, mPage);
+  if (NS_FAILED(rv)) {
+    if (rv == NS_ERROR_NOT_AVAILABLE) {
+      // We have never seen this page.  If we can add the page to history,
+      // we will try to do it later, otherwise just bail out.
+      if (!mPage.canAddToHistory) {
+        return NS_OK;
+      }
+    }
+    return rv;
+  }
+
+  if (!fetchIconFromNetwork) {
+    // There is already a valid icon or we don't want to fetch a new one,
+    // directly proceed with association.
+    RefPtr<AsyncAssociateIconToPage> event =
+        new AsyncAssociateIconToPage(mIcon, mPage, mCallback);
+    // We're already on the async thread.
+    return event->Run();
+  }
+
+  // Fetch the icon from the network, the request starts from the main-thread.
+  // When done this will associate the icon to the page and notify.
+  nsCOMPtr<nsIRunnable> event =
+      NewRunnableMethod("places::AsyncFetchAndSetIconForPage::FetchFromNetwork",
+                        this, &AsyncFetchAndSetIconForPage::FetchFromNetwork);
+  return NS_DispatchToMainThread(event);
+}
+
+nsresult AsyncFetchAndSetIconForPage::FetchFromNetwork() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mCanceled) {
+    return NS_OK;
+  }
+
+  // Ensure data is cleared, since it's going to be overwritten.
+  mIcon.payloads.Clear();
+
+  IconPayload payload;
+  mIcon.payloads.AppendElement(payload);
+
+  nsCOMPtr<nsIURI> iconURI;
+  nsresult rv = NS_NewURI(getter_AddRefs(iconURI), mIcon.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIChannel> channel;
+  rv = NS_NewChannel(getter_AddRefs(channel), iconURI, mLoadingPrincipal,
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_INHERITS_SEC_CONTEXT |
+                         nsILoadInfo::SEC_ALLOW_CHROME |
+                         nsILoadInfo::SEC_DISALLOW_SCRIPT,
+                     nsIContentPolicy::TYPE_INTERNAL_IMAGE_FAVICON);
+
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIInterfaceRequestor> listenerRequestor =
+      do_QueryInterface(reinterpret_cast<nsISupports*>(this));
+  NS_ENSURE_STATE(listenerRequestor);
+  rv = channel->SetNotificationCallbacks(listenerRequestor);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIPrivateBrowsingChannel> pbChannel = do_QueryInterface(channel);
+  if (pbChannel) {
+    rv = pbChannel->SetPrivate(mFaviconLoadPrivate);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsCOMPtr<nsISupportsPriority> priorityChannel = do_QueryInterface(channel);
+  if (priorityChannel) {
+    priorityChannel->AdjustPriority(nsISupportsPriority::PRIORITY_LOWEST);
+  }
+
+  if (StaticPrefs::network_http_tailing_enabled()) {
+    nsCOMPtr<nsIClassOfService> cos = do_QueryInterface(channel);
+    if (cos) {
+      cos->AddClassFlags(nsIClassOfService::Tail |
+                         nsIClassOfService::Throttleable);
+    }
+
+    nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(channel));
+    if (httpChannel) {
+      Unused << httpChannel->SetRequestContextID(mRequestContextID);
+    }
+  }
+
+  rv = channel->AsyncOpen(this);
+  if (NS_SUCCEEDED(rv)) {
+    mRequest = channel;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::Cancel() {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mCanceled) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  mCanceled = true;
+  if (mRequest) {
+    mRequest->CancelWithReason(NS_BINDING_ABORTED,
+                               "AsyncFetchAndSetIconForPage::Cancel"_ns);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::OnStartRequest(nsIRequest* aRequest) {
+  // mRequest should already be set from ::FetchFromNetwork, but in the case of
+  // a redirect we might get a new request, and we should make sure we keep a
+  // reference to the most current request.
+  mRequest = aRequest;
+  if (mCanceled) {
+    mRequest->Cancel(NS_BINDING_ABORTED);
+  }
+  // Don't store icons responding with Cache-Control: no-store, but always
+  // allow root domain icons.
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(aRequest);
+  if (httpChannel) {
+    bool isNoStore;
+    nsAutoCString path;
+    nsCOMPtr<nsIURI> uri;
+    if (NS_SUCCEEDED(httpChannel->GetURI(getter_AddRefs(uri))) &&
+        NS_SUCCEEDED(uri->GetFilePath(path)) &&
+        !path.EqualsLiteral("/favicon.ico") &&
+        NS_SUCCEEDED(httpChannel->IsNoStoreResponse(&isNoStore)) && isNoStore) {
+      // Abandon the network fetch.
+      mRequest->CancelWithReason(
+          NS_BINDING_ABORTED, "AsyncFetchAndSetIconForPage::OnStartRequest"_ns);
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::OnDataAvailable(nsIRequest* aRequest,
+                                             nsIInputStream* aInputStream,
+                                             uint64_t aOffset,
+                                             uint32_t aCount) {
+  MOZ_ASSERT(mIcon.payloads.Length() == 1);
+  // Limit downloads to 500KB.
+  const size_t kMaxDownloadSize = 500 * 1024;
+  if (mIcon.payloads[0].data.Length() + aCount > kMaxDownloadSize) {
+    mIcon.payloads.Clear();
+    return NS_ERROR_FILE_TOO_BIG;
+  }
+
+  nsAutoCString buffer;
+  nsresult rv = NS_ConsumeStream(aInputStream, aCount, buffer);
+  if (rv != NS_BASE_STREAM_WOULD_BLOCK && NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!mIcon.payloads[0].data.Append(buffer, fallible)) {
+    mIcon.payloads.Clear();
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::GetInterface(const nsIID& uuid, void** aResult) {
+  return QueryInterface(uuid, aResult);
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::AsyncOnChannelRedirect(
+    nsIChannel* oldChannel, nsIChannel* newChannel, uint32_t flags,
+    nsIAsyncVerifyRedirectCallback* cb) {
+  // If we've been canceled, stop the redirect with NS_BINDING_ABORTED, and
+  // handle the cancel on the original channel.
+  (void)cb->OnRedirectVerifyCallback(mCanceled ? NS_BINDING_ABORTED : NS_OK);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AsyncFetchAndSetIconForPage::OnStopRequest(nsIRequest* aRequest,
+                                           nsresult aStatusCode) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Don't need to track this anymore.
+  mRequest = nullptr;
+  if (mCanceled) {
+    return NS_OK;
+  }
+
+  nsFaviconService* favicons = nsFaviconService::GetFaviconService();
+  NS_ENSURE_STATE(favicons);
+
+  nsresult rv;
+
+  // If fetching the icon failed, bail out.
+  if (NS_FAILED(aStatusCode) || mIcon.payloads.Length() == 0) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
+  // aRequest should always QI to nsIChannel.
+  MOZ_ASSERT(channel);
+
+  MOZ_ASSERT(mIcon.payloads.Length() == 1);
+  IconPayload& payload = mIcon.payloads[0];
+
+  nsAutoCString contentType;
+  channel->GetContentType(contentType);
+  // Bug 366324 - We don't want to sniff for SVG, so rely on server-specified
+  // type.
+  if (contentType.EqualsLiteral(SVG_MIME_TYPE)) {
+    payload.mimeType.AssignLiteral(SVG_MIME_TYPE);
+    payload.width = UINT16_MAX;
+  } else {
+    NS_SniffContent(NS_DATA_SNIFFER_CATEGORY, aRequest,
+                    TO_INTBUFFER(payload.data), payload.data.Length(),
+                    payload.mimeType);
+  }
+
+  // If the icon does not have a valid MIME type, bail out.
+  if (payload.mimeType.IsEmpty()) {
+    return NS_OK;
+  }
+
+  mIcon.expiration = GetExpirationTimeFromChannel(channel);
+
+  // Telemetry probes to measure the favicon file sizes for each different file
+  // type. This allow us to measure common file sizes while also observing each
+  // type popularity.
+  if (payload.mimeType.EqualsLiteral(PNG_MIME_TYPE)) {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_PNG_SIZES,
+                          payload.data.Length());
+  } else if (payload.mimeType.EqualsLiteral("image/x-icon") ||
+             payload.mimeType.EqualsLiteral("image/vnd.microsoft.icon")) {
+    Telemetry::Accumulate(mozilla::Telemetry::PLACES_FAVICON_ICO_SIZES,
+                          payload.data.Length());
+  } else if (payload.mimeType.EqualsLiteral("image/jpeg") ||
+             payload.mimeType.EqualsLiteral("image/pjpeg")) {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_JPEG_SIZES,
+                          payload.data.Length());
+  } else if (payload.mimeType.EqualsLiteral("image/gif")) {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_GIF_SIZES,
+                          payload.data.Length());
+  } else if (payload.mimeType.EqualsLiteral("image/bmp") ||
+             payload.mimeType.EqualsLiteral("image/x-windows-bmp")) {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_BMP_SIZES,
+                          payload.data.Length());
+  } else if (payload.mimeType.EqualsLiteral(SVG_MIME_TYPE)) {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_SVG_SIZES,
+                          payload.data.Length());
+  } else {
+    Telemetry::Accumulate(Telemetry::PLACES_FAVICON_OTHER_SIZES,
+                          payload.data.Length());
+  }
+
+  rv = favicons->OptimizeIconSizes(mIcon);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If there's not valid payload, don't store the icon into to the database.
+  if (mIcon.payloads.Length() == 0) {
+    return NS_OK;
+  }
+
+  mIcon.status = ICON_STATUS_CHANGED;
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  RefPtr<AsyncAssociateIconToPage> event =
+      new AsyncAssociateIconToPage(mIcon, mPage, mCallback);
+  DB->DispatchToAsyncThread(event);
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncAssociateIconToPage
+
+AsyncAssociateIconToPage::AsyncAssociateIconToPage(
+    const IconData& aIcon, const PageData& aPage,
+    const nsMainThreadPtrHandle<nsIFaviconDataCallback>& aCallback)
+    : Runnable("places::AsyncAssociateIconToPage"),
+      mCallback(aCallback),
+      mIcon(aIcon),
+      mPage(aPage) {
+  // May be created in both threads.
+}
+
+NS_IMETHODIMP
+AsyncAssociateIconToPage::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(!mPage.guid.IsEmpty(),
+             "Page info should have been fetched already");
+  MOZ_ASSERT(mPage.canAddToHistory || !mPage.bookmarkedSpec.IsEmpty(),
+             "The page should be addable to history or a bookmark");
+
+  bool shouldUpdateIcon = mIcon.status & ICON_STATUS_CHANGED;
+  if (!shouldUpdateIcon) {
+    for (const auto& payload : mIcon.payloads) {
+      // If the entry is missing from the database, we should add it.
+      if (payload.id == 0) {
+        shouldUpdateIcon = true;
+        break;
+      }
+    }
+  }
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+
+  mozStorageTransaction transaction(
+      DB->MainConn(), false, mozIStorageConnection::TRANSACTION_IMMEDIATE);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  nsresult rv;
+  if (shouldUpdateIcon) {
+    rv = SetIconInfo(DB, mIcon);
+    if (NS_FAILED(rv)) {
+      (void)transaction.Commit();
+      return rv;
+    }
+
+    mIcon.status = (mIcon.status & ~(ICON_STATUS_CACHED)) | ICON_STATUS_SAVED;
+  }
+
+  // If the page does not have an id, don't try to insert a new one, cause we
+  // don't know where the page comes from.  Not doing so we may end adding
+  // a page that otherwise we'd explicitly ignore, like a POST or an error page.
+  if (mPage.placeId == 0) {
+    rv = transaction.Commit();
+    NS_ENSURE_SUCCESS(rv, rv);
+    return NS_OK;
+  }
+
+  // Expire old favicons to keep up with website changes. Associated icons must
+  // be expired also when storing a root favicon, because a page may change to
+  // only have a root favicon.
+  // Note that here we could also be in the process of adding further payloads
+  // to a page, and we don't want to expire just added payloads. For this
+  // reason we only remove expired payloads.
+  // Oprhan icons are not removed at this time because it'd be expensive. The
+  // privacy implications are limited, since history removal methods also expire
+  // orphan icons.
+  if (mPage.id > 0) {
+    nsCOMPtr<mozIStorageStatement> stmt;
+    stmt = DB->GetStatement(
+        "DELETE FROM moz_icons_to_pages "
+        "WHERE page_id = :page_id "
+        "AND expire_ms < strftime('%s','now','localtime','utc') * 1000 ");
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+    rv = stmt->BindInt64ByName("page_id"_ns, mPage.id);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Don't associate pages to root domain icons, since those will be returned
+  // regardless.  This saves a lot of work and database space since we don't
+  // need to store urls and relations.
+  // Though, this is possible only if both the page and the icon have the same
+  // host, otherwise we couldn't relate them.
+  if (!mIcon.rootIcon || !mIcon.host.Equals(mPage.host)) {
+    // The page may have associated payloads already, and those could have to be
+    // expired. For example at a certain point a page could decide to stop
+    // serving its usual 16px and 32px pngs, and use an svg instead. On the
+    // other side, we could also be in the process of adding more payloads to
+    // this page, and we should not expire the payloads we just added. For this,
+    // we use the expiration field as an indicator and remove relations based on
+    // it being elapsed. We don't remove orphan icons at this time since it
+    // would have a cost. The privacy hit is limited since history removal
+    // methods already expire orphan icons.
+    if (mPage.id == 0) {
+      // We need to create the page entry.
+      nsCOMPtr<mozIStorageStatement> stmt;
+      stmt = DB->GetStatement(
+          "INSERT OR IGNORE INTO moz_pages_w_icons (page_url, page_url_hash) "
+          "VALUES (:page_url, hash(:page_url)) ");
+      NS_ENSURE_STATE(stmt);
+      mozStorageStatementScoper scoper(stmt);
+      rv = URIBinder::Bind(stmt, "page_url"_ns, mPage.spec);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    // Then we can create the relations.
+    nsCOMPtr<mozIStorageStatement> stmt;
+    stmt = DB->GetStatement(
+        "INSERT INTO moz_icons_to_pages (page_id, icon_id, expire_ms) "
+        "VALUES ((SELECT id from moz_pages_w_icons WHERE page_url_hash = "
+        "hash(:page_url) AND page_url = :page_url), "
+        ":icon_id, :expire) "
+        "ON CONFLICT(page_id, icon_id) DO "
+        "UPDATE SET expire_ms = :expire ");
+    NS_ENSURE_STATE(stmt);
+
+    // For some reason using BindingParamsArray here fails execution, so we must
+    // execute the statements one by one.
+    // In the future we may want to investigate the reasons, sounds like related
+    // to contraints.
+    for (const auto& payload : mIcon.payloads) {
+      mozStorageStatementScoper scoper(stmt);
+      nsCOMPtr<mozIStorageBindingParams> params;
+      rv = URIBinder::Bind(stmt, "page_url"_ns, mPage.spec);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->BindInt64ByName("icon_id"_ns, payload.id);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->BindInt64ByName("expire"_ns, mIcon.expiration / 1000);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  mIcon.status |= ICON_STATUS_ASSOCIATED;
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Finally, dispatch an event to the main thread to notify observers.
+  nsCOMPtr<nsIRunnable> event =
+      new NotifyIconObservers(mIcon, mPage, mCallback);
+  rv = NS_DispatchToMainThread(event);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If there is a bookmarked page that redirects to this one, try to update its
+  // icon as well.
+  if (!mPage.bookmarkedSpec.IsEmpty() &&
+      !mPage.bookmarkedSpec.Equals(mPage.spec)) {
+    // Create a new page struct to avoid polluting it with old data.
+    PageData bookmarkedPage;
+    bookmarkedPage.spec = mPage.bookmarkedSpec;
+    RefPtr<Database> DB = Database::GetDatabase();
+    if (DB && NS_SUCCEEDED(FetchPageInfo(DB, bookmarkedPage))) {
+      // This will be silent, so be sure to not pass in the current callback.
+      nsMainThreadPtrHandle<nsIFaviconDataCallback> nullCallback;
+      RefPtr<AsyncAssociateIconToPage> event =
+          new AsyncAssociateIconToPage(mIcon, bookmarkedPage, nullCallback);
+      Unused << event->Run();
+    }
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncGetFaviconURLForPage
+
+AsyncGetFaviconURLForPage::AsyncGetFaviconURLForPage(
+    const nsACString& aPageSpec, const nsACString& aPageHost,
+    uint16_t aPreferredWidth, nsIFaviconDataCallback* aCallback)
+    : Runnable("places::AsyncGetFaviconURLForPage"),
+      mPreferredWidth(aPreferredWidth == 0 ? UINT16_MAX : aPreferredWidth),
+      mCallback(new nsMainThreadPtrHolder<nsIFaviconDataCallback>(
+          "AsyncGetFaviconURLForPage::mCallback", aCallback)) {
+  MOZ_ASSERT(NS_IsMainThread());
+  mPageSpec.Assign(aPageSpec);
+  mPageHost.Assign(aPageHost);
+}
+
+NS_IMETHODIMP
+AsyncGetFaviconURLForPage::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  IconData iconData;
+  nsresult rv =
+      FetchIconPerSpec(DB, mPageSpec, mPageHost, iconData, mPreferredWidth);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Now notify our callback of the icon spec we retrieved, even if empty.
+  PageData pageData;
+  pageData.spec.Assign(mPageSpec);
+
+  nsCOMPtr<nsIRunnable> event =
+      new NotifyIconObservers(iconData, pageData, mCallback);
+  rv = NS_DispatchToMainThread(event);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncGetFaviconDataForPage
+
+AsyncGetFaviconDataForPage::AsyncGetFaviconDataForPage(
+    const nsACString& aPageSpec, const nsACString& aPageHost,
+    uint16_t aPreferredWidth, nsIFaviconDataCallback* aCallback)
+    : Runnable("places::AsyncGetFaviconDataForPage"),
+      mPreferredWidth(aPreferredWidth == 0 ? UINT16_MAX : aPreferredWidth),
+      mCallback(new nsMainThreadPtrHolder<nsIFaviconDataCallback>(
+          "AsyncGetFaviconDataForPage::mCallback", aCallback)) {
+  MOZ_ASSERT(NS_IsMainThread());
+  mPageSpec.Assign(aPageSpec);
+  mPageHost.Assign(aPageHost);
+}
+
+NS_IMETHODIMP
+AsyncGetFaviconDataForPage::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  IconData iconData;
+  nsresult rv =
+      FetchIconPerSpec(DB, mPageSpec, mPageHost, iconData, mPreferredWidth);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!iconData.spec.IsEmpty()) {
+    rv = FetchIconInfo(DB, mPreferredWidth, iconData);
+    if (NS_FAILED(rv)) {
+      iconData.spec.Truncate();
+    }
+  }
+
+  PageData pageData;
+  pageData.spec.Assign(mPageSpec);
+
+  nsCOMPtr<nsIRunnable> event =
+      new NotifyIconObservers(iconData, pageData, mCallback);
+  rv = NS_DispatchToMainThread(event);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncReplaceFaviconData
+
+AsyncReplaceFaviconData::AsyncReplaceFaviconData(const IconData& aIcon)
+    : Runnable("places::AsyncReplaceFaviconData"), mIcon(aIcon) {
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+NS_IMETHODIMP
+AsyncReplaceFaviconData::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+
+  mozStorageTransaction transaction(
+      DB->MainConn(), false, mozIStorageConnection::TRANSACTION_IMMEDIATE);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  nsresult rv = SetIconInfo(DB, mIcon, true);
+  if (rv == NS_ERROR_NOT_AVAILABLE) {
+    // There's no previous icon to replace, we don't need to do anything.
+    (void)transaction.Commit();
+    return NS_OK;
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // We can invalidate the cache version since we now persist the icon.
+  nsCOMPtr<nsIRunnable> event = NewRunnableMethod(
+      "places::AsyncReplaceFaviconData::RemoveIconDataCacheEntry", this,
+      &AsyncReplaceFaviconData::RemoveIconDataCacheEntry);
+  rv = NS_DispatchToMainThread(event);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult AsyncReplaceFaviconData::RemoveIconDataCacheEntry() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIURI> iconURI;
+  nsresult rv = NS_NewURI(getter_AddRefs(iconURI), mIcon.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsFaviconService* favicons = nsFaviconService::GetFaviconService();
+  NS_ENSURE_STATE(favicons);
+  favicons->mUnassociatedIcons.RemoveEntry(iconURI);
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// NotifyIconObservers
+
+NotifyIconObservers::NotifyIconObservers(
+    const IconData& aIcon, const PageData& aPage,
+    const nsMainThreadPtrHandle<nsIFaviconDataCallback>& aCallback)
+    : Runnable("places::NotifyIconObservers"),
+      mCallback(aCallback),
+      mIcon(aIcon),
+      mPage(aPage) {}
+
+// MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is marked
+// MOZ_CAN_RUN_SCRIPT.  See bug 1535398.
+MOZ_CAN_RUN_SCRIPT_BOUNDARY
+NS_IMETHODIMP
+NotifyIconObservers::Run() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  nsCOMPtr<nsIURI> iconURI;
+  if (!mIcon.spec.IsEmpty()) {
+    if (!NS_WARN_IF(
+            NS_FAILED(NS_NewURI(getter_AddRefs(iconURI), mIcon.spec)))) {
+      // Notify observers only if something changed.
+      if (mIcon.status & ICON_STATUS_SAVED ||
+          mIcon.status & ICON_STATUS_ASSOCIATED) {
+        nsCOMPtr<nsIURI> pageURI;
+        if (!NS_WARN_IF(
+                NS_FAILED(NS_NewURI(getter_AddRefs(pageURI), mPage.spec)))) {
+          // Invalide page-icon image cache, since the icon is about to change.
+          nsFaviconService* favicons = nsFaviconService::GetFaviconService();
+          MOZ_ASSERT(favicons);
+          if (favicons) {
+            nsCString pageIconSpec("page-icon:");
+            pageIconSpec.Append(mPage.spec);
+            nsCOMPtr<nsIURI> pageIconURI;
+            if (NS_SUCCEEDED(
+                    NS_NewURI(getter_AddRefs(pageIconURI), pageIconSpec))) {
+              favicons->ClearImageCache(pageIconURI);
+            }
+          }
+
+          // Notify about the favicon change.
+          dom::Sequence<OwningNonNull<dom::PlacesEvent>> events;
+          RefPtr<dom::PlacesFavicon> faviconEvent = new dom::PlacesFavicon();
+          AppendUTF8toUTF16(mPage.spec, faviconEvent->mUrl);
+          AppendUTF8toUTF16(mIcon.spec, faviconEvent->mFaviconUrl);
+          faviconEvent->mPageGuid.Assign(mPage.guid);
+          bool success =
+              !!events.AppendElement(faviconEvent.forget(), fallible);
+          MOZ_RELEASE_ASSERT(success);
+          dom::PlacesObservers::NotifyListeners(events);
+        }
+      }
+    }
+  }
+
+  if (!mCallback) {
+    return NS_OK;
+  }
+
+  if (mIcon.payloads.Length() > 0) {
+    IconPayload& payload = mIcon.payloads[0];
+    return mCallback->OnComplete(iconURI, payload.data.Length(),
+                                 TO_INTBUFFER(payload.data), payload.mimeType,
+                                 payload.width);
+  }
+  return mCallback->OnComplete(iconURI, 0, TO_INTBUFFER(EmptyCString()), ""_ns,
+                               0);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncCopyFavicons
+
+AsyncCopyFavicons::AsyncCopyFavicons(PageData& aFromPage, PageData& aToPage,
+                                     nsIFaviconDataCallback* aCallback)
+    : Runnable("places::AsyncCopyFavicons"),
+      mFromPage(aFromPage),
+      mToPage(aToPage),
+      mCallback(new nsMainThreadPtrHolder<nsIFaviconDataCallback>(
+          "AsyncCopyFavicons::mCallback", aCallback)) {
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+NS_IMETHODIMP
+AsyncCopyFavicons::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  IconData icon;
+
+  // Ensure we'll callback and dispatch notifications to the main-thread.
+  auto cleanup = MakeScopeExit([&]() {
+    // If we bailed out early, just return a null icon uri, since we didn't
+    // copy anything.
+    if (!(icon.status & ICON_STATUS_ASSOCIATED)) {
+      icon.spec.Truncate();
+    }
+    nsCOMPtr<nsIRunnable> event =
+        new NotifyIconObservers(icon, mToPage, mCallback);
+    NS_DispatchToMainThread(event);
+  });
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+
+  nsresult rv = FetchPageInfo(DB, mToPage);
+  if (rv == NS_ERROR_NOT_AVAILABLE || !mToPage.placeId) {
+    // We have never seen this page, or we can't add this page to history and
+    // and it's not a bookmark. We won't add the page.
+    return NS_OK;
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Get just one icon, to check whether the page has any, and to notify later.
+  rv = FetchIconPerSpec(DB, mFromPage.spec, ""_ns, icon, UINT16_MAX);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (icon.spec.IsEmpty()) {
+    // There's nothing to copy.
+    return NS_OK;
+  }
+
+  // Insert an entry in moz_pages_w_icons if needed.
+  if (!mToPage.id) {
+    // We need to create the page entry.
+    nsCOMPtr<mozIStorageStatement> stmt;
+    stmt = DB->GetStatement(
+        "INSERT OR IGNORE INTO moz_pages_w_icons (page_url, page_url_hash) "
+        "VALUES (:page_url, hash(:page_url)) ");
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+    rv = URIBinder::Bind(stmt, "page_url"_ns, mToPage.spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+    // Required to to fetch the id and the guid.
+    rv = FetchPageInfo(DB, mToPage);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Create the relations.
+  nsCOMPtr<mozIStorageStatement> stmt = DB->GetStatement(
+      "INSERT OR IGNORE INTO moz_icons_to_pages (page_id, icon_id, expire_ms) "
+      "SELECT :id, icon_id, expire_ms "
+      "FROM moz_icons_to_pages "
+      "WHERE page_id = (SELECT id FROM moz_pages_w_icons WHERE page_url_hash = "
+      "hash(:url) AND page_url = :url) ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+  rv = stmt->BindInt64ByName("id"_ns, mToPage.id);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = URIBinder::Bind(stmt, "url"_ns, mFromPage.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Setting this will make us send pageChanged notifications.
+  // The scope exit will take care of the callback and notifications.
+  icon.status |= ICON_STATUS_ASSOCIATED;
+
+  return NS_OK;
+}
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/FaviconHelpers.h b/toolkit/components/places/FaviconHelpers.h
new file mode 100644
index 0000000000..ba3407722c
--- /dev/null
+++ b/toolkit/components/places/FaviconHelpers.h
@@ -0,0 +1,327 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#pragma once
+
+#include "nsIFaviconService.h"
+#include "nsIChannelEventSink.h"
+#include "nsIInterfaceRequestor.h"
+#include "nsIStreamListener.h"
+#include "mozIPlacesPendingOperation.h"
+#include "nsThreadUtils.h"
+#include "nsProxyRelease.h"
+#include "imgLoader.h"
+
+class nsIPrincipal;
+
+#include "Database.h"
+#include "mozilla/storage.h"
+
+#define ICON_STATUS_UNKNOWN 0
+#define ICON_STATUS_CHANGED 1 << 0
+#define ICON_STATUS_SAVED 1 << 1
+#define ICON_STATUS_ASSOCIATED 1 << 2
+#define ICON_STATUS_CACHED 1 << 3
+
+#define TO_CHARBUFFER(_buffer) \
+  reinterpret_cast<char*>(const_cast<uint8_t*>(_buffer))
+#define TO_INTBUFFER(_string) \
+  reinterpret_cast<uint8_t*>(const_cast<char*>(_string.get()))
+
+#define PNG_MIME_TYPE "image/png"
+#define SVG_MIME_TYPE "image/svg+xml"
+
+// Always ensure a minimum expiration time, so icons are not already expired
+// on addition.
+#define MIN_FAVICON_EXPIRATION ((PRTime)1 * 24 * 60 * 60 * PR_USEC_PER_SEC)
+// The maximum time we will keep a favicon around.  We always ask the cache
+// first and default to this value if we can't get a time, or the time we get
+// is far in the future.
+#define MAX_FAVICON_EXPIRATION ((PRTime)7 * 24 * 60 * 60 * PR_USEC_PER_SEC)
+
+namespace mozilla {
+namespace places {
+
+/**
+ * Indicates when a icon should be fetched from network.
+ */
+enum AsyncFaviconFetchMode { FETCH_NEVER = 0, FETCH_IF_MISSING, FETCH_ALWAYS };
+
+/**
+ * Represents one of the payloads (frames) of an icon entry.
+ */
+struct IconPayload {
+  IconPayload() : id(0), width(0) {
+    data.SetIsVoid(true);
+    mimeType.SetIsVoid(true);
+  }
+
+  int64_t id;
+  uint16_t width;
+  nsCString data;
+  nsCString mimeType;
+};
+
+/**
+ * Represents an icon entry.
+ */
+struct IconData {
+  IconData()
+      : expiration(0),
+        fetchMode(FETCH_NEVER),
+        status(ICON_STATUS_UNKNOWN),
+        rootIcon(0) {}
+
+  nsCString spec;
+  nsCString host;
+  PRTime expiration;
+  enum AsyncFaviconFetchMode fetchMode;
+  uint16_t status;  // This is a bitset, see ICON_STATUS_* defines above.
+  uint8_t rootIcon;
+  CopyableTArray<IconPayload> payloads;
+};
+
+/**
+ * Data cache for a page entry.
+ */
+struct PageData {
+  PageData() : id(0), placeId(0), canAddToHistory(true) {
+    guid.SetIsVoid(true);
+  }
+
+  int64_t id;       // This is the moz_pages_w_icons id.
+  int64_t placeId;  // This is the moz_places page id.
+  nsCString spec;
+  nsCString host;
+  nsCString bookmarkedSpec;
+  bool canAddToHistory;  // False for disabled history and unsupported schemas.
+  nsCString guid;
+};
+
+/**
+ * Info for a frame.
+ */
+struct FrameData {
+  FrameData(uint16_t aIndex, uint16_t aWidth) : index(aIndex), width(aWidth) {}
+
+  uint16_t index;
+  uint16_t width;
+};
+
+/**
+ * Async fetches icon from database or network, associates it with the required
+ * page and finally notifies the change.
+ */
+class AsyncFetchAndSetIconForPage final : public Runnable,
+                                          public nsIStreamListener,
+                                          public nsIInterfaceRequestor,
+                                          public nsIChannelEventSink,
+                                          public mozIPlacesPendingOperation {
+ public:
+  NS_DECL_NSIRUNNABLE
+  NS_DECL_NSISTREAMLISTENER
+  NS_DECL_NSIINTERFACEREQUESTOR
+  NS_DECL_NSICHANNELEVENTSINK
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_MOZIPLACESPENDINGOPERATION
+  NS_DECL_ISUPPORTS_INHERITED
+
+  /**
+   * Constructor.
+   *
+   * @param aIcon
+   *        Icon to be fetched and associated.
+   * @param aPage
+   *        Page to which associate the icon.
+   * @param aFaviconLoadPrivate
+   *        Whether this favicon load is in private browsing.
+   * @param aCallback
+   *        Function to be called when the fetch-and-associate process finishes.
+   * @param aLoadingPrincipal
+   *        LoadingPrincipal of the icon to be fetched.
+   */
+  AsyncFetchAndSetIconForPage(IconData& aIcon, PageData& aPage,
+                              bool aFaviconLoadPrivate,
+                              nsIFaviconDataCallback* aCallback,
+                              nsIPrincipal* aLoadingPrincipal,
+                              uint64_t aRequestContextID);
+
+ private:
+  nsresult FetchFromNetwork();
+  virtual ~AsyncFetchAndSetIconForPage() = default;
+
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+  IconData mIcon;
+  PageData mPage;
+  const bool mFaviconLoadPrivate;
+  nsMainThreadPtrHandle<nsIPrincipal> mLoadingPrincipal;
+  bool mCanceled;
+  nsCOMPtr<nsIRequest> mRequest;
+  uint64_t mRequestContextID;
+};
+
+/**
+ * Associates the icon to the required page, finally dispatches an event to the
+ * main thread to notify the change to observers.
+ */
+class AsyncAssociateIconToPage final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  /**
+   * Constructor.
+   *
+   * @param aIcon
+   *        Icon to be associated.
+   * @param aPage
+   *        Page to which associate the icon.
+   * @param aCallback
+   *        Function to be called when the associate process finishes.
+   */
+  AsyncAssociateIconToPage(
+      const IconData& aIcon, const PageData& aPage,
+      const nsMainThreadPtrHandle<nsIFaviconDataCallback>& aCallback);
+
+ private:
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+  IconData mIcon;
+  PageData mPage;
+};
+
+/**
+ * Asynchronously tries to get the URL of a page's favicon, then notifies the
+ * given observer.
+ */
+class AsyncGetFaviconURLForPage final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  /**
+   * Constructor.
+   *
+   * @param aPageSpec
+   *        URL of the page whose favicon's URL we're fetching
+   * @param aPageHost
+   *        Host of the page whose favicon's URL we're fetching
+   * @param aCallback
+   *        function to be called once finished
+   * @param aPreferredWidth
+   *        The preferred size for the icon
+   */
+  AsyncGetFaviconURLForPage(const nsACString& aPageSpec,
+                            const nsACString& aPageHost,
+                            uint16_t aPreferredWidth,
+                            nsIFaviconDataCallback* aCallback);
+
+ private:
+  uint16_t mPreferredWidth;
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+  nsCString mPageSpec;
+  nsCString mPageHost;
+};
+
+/**
+ * Asynchronously tries to get the URL and data of a page's favicon, then
+ * notifies the given observer.
+ */
+class AsyncGetFaviconDataForPage final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  /**
+   * Constructor.
+   *
+   * @param aPageSpec
+   *        URL of the page whose favicon URL and data we're fetching
+   * @param aPageHost
+   *        Host of the page whose favicon's URL we're fetching
+   * @param aPreferredWidth
+   *        The preferred size of the icon.  We will try to return an icon close
+   *        to this size.
+   * @param aCallback
+   *        function to be called once finished
+   */
+  AsyncGetFaviconDataForPage(const nsACString& aPageSpec,
+                             const nsACString& aPageHost,
+                             uint16_t aPreferredWidth,
+                             nsIFaviconDataCallback* aCallback);
+
+ private:
+  uint16_t mPreferredWidth;
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+  nsCString mPageSpec;
+  nsCString mPageHost;
+};
+
+class AsyncReplaceFaviconData final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  explicit AsyncReplaceFaviconData(const IconData& aIcon);
+
+ private:
+  nsresult RemoveIconDataCacheEntry();
+
+  IconData mIcon;
+};
+
+/**
+ * Notifies the icon change to favicon observers.
+ */
+class NotifyIconObservers final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  /**
+   * Constructor.
+   *
+   * @param aIcon
+   *        Icon information. Can be empty if no icon is associated to the page.
+   * @param aPage
+   *        Page to which the icon information applies.
+   * @param aCallback
+   *        Function to be notified in all cases.
+   */
+  NotifyIconObservers(
+      const IconData& aIcon, const PageData& aPage,
+      const nsMainThreadPtrHandle<nsIFaviconDataCallback>& aCallback);
+
+ private:
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+  IconData mIcon;
+  PageData mPage;
+};
+
+/**
+ * Copies Favicons from one page to another one.
+ */
+class AsyncCopyFavicons final : public Runnable {
+ public:
+  NS_DECL_NSIRUNNABLE
+
+  /**
+   * Constructor.
+   *
+   * @param aFromPage
+   *        The originating page.
+   * @param aToPage
+   *        The destination page.
+   * @param aFaviconLoadPrivate
+   *        Whether this favicon load is in private browsing.
+   * @param aCallback
+   *        An optional callback to invoke when done.
+   */
+  AsyncCopyFavicons(PageData& aFromPage, PageData& aToPage,
+                    nsIFaviconDataCallback* aCallback);
+
+ private:
+  PageData mFromPage;
+  PageData mToPage;
+  nsMainThreadPtrHandle<nsIFaviconDataCallback> mCallback;
+};
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/Helpers.cpp b/toolkit/components/places/Helpers.cpp
new file mode 100644
index 0000000000..90ab263ec1
--- /dev/null
+++ b/toolkit/components/places/Helpers.cpp
@@ -0,0 +1,382 @@
+/* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Helpers.h"
+#include "mozIStorageError.h"
+#include "prio.h"
+#include "nsIFile.h"
+#include "nsReadableUtils.h"
+#include "nsString.h"
+#include "nsNavHistory.h"
+#include "mozilla/Base64.h"
+#include "mozilla/HashFunctions.h"
+#include "mozilla/RandomNum.h"
+#include <algorithm>
+#include "mozilla/Services.h"
+
+// The length of guids that are used by history and bookmarks.
+#define GUID_LENGTH 12
+
+// Maximum number of chars to use for calculating hashes. This value has been
+// picked to ensure low hash collisions on a real world common places.sqlite.
+// While collisions are not a big deal for functionality, a low ratio allows
+// for slightly more efficient SELECTs.
+#define MAX_CHARS_TO_HASH 1500U
+
+extern "C" {
+
+// Generates a new Places GUID. This function uses C linkage because it's
+// called from the Rust synced bookmarks mirror, on the storage thread.
+nsresult NS_GeneratePlacesGUID(nsACString* _guid) {
+  return mozilla::places::GenerateGUID(*_guid);
+}
+
+}  // extern "C"
+
+namespace mozilla {
+namespace places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// AsyncStatementCallback
+
+NS_IMPL_ISUPPORTS(AsyncStatementCallback, mozIStorageStatementCallback)
+
+NS_IMETHODIMP
+WeakAsyncStatementCallback::HandleResult(mozIStorageResultSet* aResultSet) {
+  MOZ_ASSERT(false, "Was not expecting a resultset, but got it.");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WeakAsyncStatementCallback::HandleCompletion(uint16_t aReason) { return NS_OK; }
+
+NS_IMETHODIMP
+WeakAsyncStatementCallback::HandleError(mozIStorageError* aError) {
+#ifdef DEBUG
+  int32_t result;
+  nsresult rv = aError->GetResult(&result);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString message;
+  rv = aError->GetMessage(message);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString warnMsg;
+  warnMsg.AppendLiteral(
+      "An error occurred while executing an async statement: ");
+  warnMsg.AppendInt(result);
+  warnMsg.Append(' ');
+  warnMsg.Append(message);
+  NS_WARNING(warnMsg.get());
+#endif
+
+  return NS_OK;
+}
+
+#define URI_TO_URLCSTRING(uri, spec)    \
+  nsAutoCString spec;                   \
+  if (NS_FAILED(aURI->GetSpec(spec))) { \
+    return NS_ERROR_UNEXPECTED;         \
+  }
+
+// Bind URI to statement by index.
+nsresult  // static
+URIBinder::Bind(mozIStorageStatement* aStatement, int32_t aIndex,
+                nsIURI* aURI) {
+  NS_ASSERTION(aStatement, "Must have non-null statement");
+  NS_ASSERTION(aURI, "Must have non-null uri");
+
+  URI_TO_URLCSTRING(aURI, spec);
+  return URIBinder::Bind(aStatement, aIndex, spec);
+}
+
+// Statement URLCString to statement by index.
+nsresult  // static
+URIBinder::Bind(mozIStorageStatement* aStatement, int32_t index,
+                const nsACString& aURLString) {
+  NS_ASSERTION(aStatement, "Must have non-null statement");
+  return aStatement->BindUTF8StringByIndex(
+      index, StringHead(aURLString, URI_LENGTH_MAX));
+}
+
+// Bind URI to statement by name.
+nsresult  // static
+URIBinder::Bind(mozIStorageStatement* aStatement, const nsACString& aName,
+                nsIURI* aURI) {
+  NS_ASSERTION(aStatement, "Must have non-null statement");
+  NS_ASSERTION(aURI, "Must have non-null uri");
+
+  URI_TO_URLCSTRING(aURI, spec);
+  return URIBinder::Bind(aStatement, aName, spec);
+}
+
+// Bind URLCString to statement by name.
+nsresult  // static
+URIBinder::Bind(mozIStorageStatement* aStatement, const nsACString& aName,
+                const nsACString& aURLString) {
+  NS_ASSERTION(aStatement, "Must have non-null statement");
+  return aStatement->BindUTF8StringByName(
+      aName, StringHead(aURLString, URI_LENGTH_MAX));
+}
+
+// Bind URI to params by index.
+nsresult  // static
+URIBinder::Bind(mozIStorageBindingParams* aParams, int32_t aIndex,
+                nsIURI* aURI) {
+  NS_ASSERTION(aParams, "Must have non-null statement");
+  NS_ASSERTION(aURI, "Must have non-null uri");
+
+  URI_TO_URLCSTRING(aURI, spec);
+  return URIBinder::Bind(aParams, aIndex, spec);
+}
+
+// Bind URLCString to params by index.
+nsresult  // static
+URIBinder::Bind(mozIStorageBindingParams* aParams, int32_t index,
+                const nsACString& aURLString) {
+  NS_ASSERTION(aParams, "Must have non-null statement");
+  return aParams->BindUTF8StringByIndex(index,
+                                        StringHead(aURLString, URI_LENGTH_MAX));
+}
+
+// Bind URI to params by name.
+nsresult  // static
+URIBinder::Bind(mozIStorageBindingParams* aParams, const nsACString& aName,
+                nsIURI* aURI) {
+  NS_ASSERTION(aParams, "Must have non-null params array");
+  NS_ASSERTION(aURI, "Must have non-null uri");
+
+  URI_TO_URLCSTRING(aURI, spec);
+  return URIBinder::Bind(aParams, aName, spec);
+}
+
+// Bind URLCString to params by name.
+nsresult  // static
+URIBinder::Bind(mozIStorageBindingParams* aParams, const nsACString& aName,
+                const nsACString& aURLString) {
+  NS_ASSERTION(aParams, "Must have non-null params array");
+
+  nsresult rv = aParams->BindUTF8StringByName(
+      aName, StringHead(aURLString, URI_LENGTH_MAX));
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+#undef URI_TO_URLCSTRING
+
+nsresult GetReversedHostname(nsIURI* aURI, nsString& aRevHost) {
+  nsAutoCString forward8;
+  nsresult rv = aURI->GetHost(forward8);
+  // Not all URIs have a host.
+  if (NS_FAILED(rv)) return rv;
+
+  // can't do reversing in UTF8, better use 16-bit chars
+  GetReversedHostname(NS_ConvertUTF8toUTF16(forward8), aRevHost);
+  return NS_OK;
+}
+
+void GetReversedHostname(const nsString& aForward, nsString& aRevHost) {
+  ReverseString(aForward, aRevHost);
+  aRevHost.Append(char16_t('.'));
+}
+
+void ReverseString(const nsString& aInput, nsString& aReversed) {
+  aReversed.Truncate(0);
+  for (int32_t i = aInput.Length() - 1; i >= 0; i--) {
+    aReversed.Append(aInput[i]);
+  }
+}
+
+nsresult GenerateGUID(nsACString& _guid) {
+  _guid.Truncate();
+
+  // Request raw random bytes and base64url encode them.  For each set of three
+  // bytes, we get one character.
+  const uint32_t kRequiredBytesLength =
+      static_cast<uint32_t>(GUID_LENGTH / 4 * 3);
+
+  uint8_t buffer[kRequiredBytesLength];
+  if (!mozilla::GenerateRandomBytesFromOS(buffer, kRequiredBytesLength)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = Base64URLEncode(kRequiredBytesLength, buffer,
+                                Base64URLEncodePaddingPolicy::Omit, _guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  NS_ASSERTION(_guid.Length() == GUID_LENGTH, "GUID is not the right size!");
+  return NS_OK;
+}
+
+bool IsValidGUID(const nsACString& aGUID) {
+  nsCString::size_type len = aGUID.Length();
+  if (len != GUID_LENGTH) {
+    return false;
+  }
+
+  for (nsCString::size_type i = 0; i < len; i++) {
+    char c = aGUID[i];
+    if ((c >= 'a' && c <= 'z') ||  // a-z
+        (c >= 'A' && c <= 'Z') ||  // A-Z
+        (c >= '0' && c <= '9') ||  // 0-9
+        c == '-' || c == '_') {    // - or _
+      continue;
+    }
+    return false;
+  }
+  return true;
+}
+
+void TruncateTitle(const nsACString& aTitle, nsACString& aTrimmed) {
+  if (aTitle.IsVoid()) {
+    return;
+  }
+  aTrimmed = aTitle;
+  if (aTitle.Length() > TITLE_LENGTH_MAX) {
+    aTrimmed = StringHead(aTitle, TITLE_LENGTH_MAX);
+  }
+}
+
+PRTime RoundToMilliseconds(PRTime aTime) {
+  return aTime - (aTime % PR_USEC_PER_MSEC);
+}
+
+PRTime RoundedPRNow() { return RoundToMilliseconds(PR_Now()); }
+
+nsresult HashURL(const nsACString& aSpec, const nsACString& aMode,
+                 uint64_t* _hash) {
+  NS_ENSURE_ARG_POINTER(_hash);
+
+  // HashString doesn't stop at the string boundaries if a length is passed to
+  // it, so ensure to pass a proper value.
+  const uint32_t maxLenToHash =
+      std::min(static_cast<uint32_t>(aSpec.Length()), MAX_CHARS_TO_HASH);
+
+  if (aMode.IsEmpty()) {
+    // URI-like strings (having a prefix before a colon), are handled specially,
+    // as a 48 bit hash, where first 16 bits are the prefix hash, while the
+    // other 32 are the string hash.
+    // The 16 bits have been decided based on the fact hashing all of the IANA
+    // known schemes, plus "places", does not generate collisions.
+    // Since we only care about schemes, we just search in the first 50 chars.
+    // The longest known IANA scheme, at this time, is 30 chars.
+    const nsDependentCSubstring& strHead = StringHead(aSpec, 50);
+    nsACString::const_iterator start, tip, end;
+    strHead.BeginReading(tip);
+    start = tip;
+    strHead.EndReading(end);
+    uint32_t strHash = HashString(aSpec.BeginReading(), maxLenToHash);
+    if (FindCharInReadable(':', tip, end)) {
+      const nsDependentCSubstring& prefix = Substring(start, tip);
+      uint64_t prefixHash =
+          static_cast<uint64_t>(HashString(prefix) & 0x0000FFFF);
+      // The second half of the url is more likely to be unique, so we add it.
+      *_hash = (prefixHash << 32) + strHash;
+    } else {
+      *_hash = strHash;
+    }
+  } else if (aMode.EqualsLiteral("prefix_lo")) {
+    // Keep only 16 bits.
+    *_hash = static_cast<uint64_t>(
+                 HashString(aSpec.BeginReading(), maxLenToHash) & 0x0000FFFF)
+             << 32;
+  } else if (aMode.EqualsLiteral("prefix_hi")) {
+    // Keep only 16 bits.
+    *_hash = static_cast<uint64_t>(
+                 HashString(aSpec.BeginReading(), maxLenToHash) & 0x0000FFFF)
+             << 32;
+    // Make this a prefix upper bound by filling the lowest 32 bits.
+    *_hash += 0xFFFFFFFF;
+  } else {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+bool GetHiddenState(bool aIsRedirect, uint32_t aTransitionType) {
+  return aTransitionType == nsINavHistoryService::TRANSITION_FRAMED_LINK ||
+         aTransitionType == nsINavHistoryService::TRANSITION_EMBED ||
+         aIsRedirect;
+}
+
+nsresult TokenizeQueryString(const nsACString& aQuery,
+                             nsTArray<QueryKeyValuePair>* aTokens) {
+  // Strip off the "place:" prefix
+  const uint32_t prefixlen = 6;  // = strlen("place:");
+  nsCString query;
+  if (aQuery.Length() >= prefixlen &&
+      Substring(aQuery, 0, prefixlen).EqualsLiteral("place:"))
+    query = Substring(aQuery, prefixlen);
+  else
+    query = aQuery;
+
+  int32_t keyFirstIndex = 0;
+  int32_t equalsIndex = 0;
+  for (uint32_t i = 0; i < query.Length(); i++) {
+    if (query[i] == '&') {
+      // new clause, save last one
+      if (i - keyFirstIndex > 1) {
+        // XXX(Bug 1631371) Check if this should use a fallible operation as it
+        // pretended earlier, or change the return type to void.
+        aTokens->AppendElement(
+            QueryKeyValuePair(query, keyFirstIndex, equalsIndex, i));
+      }
+      keyFirstIndex = equalsIndex = i + 1;
+    } else if (query[i] == '=') {
+      equalsIndex = i;
+    }
+  }
+
+  // handle last pair, if any
+  if (query.Length() - keyFirstIndex > 1) {
+    // XXX(Bug 1631371) Check if this should use a fallible operation as it
+    // pretended earlier, or change the return type to void.
+    aTokens->AppendElement(
+        QueryKeyValuePair(query, keyFirstIndex, equalsIndex, query.Length()));
+  }
+  return NS_OK;
+}
+
+void TokensToQueryString(const nsTArray<QueryKeyValuePair>& aTokens,
+                         nsACString& aQuery) {
+  aQuery = "place:"_ns;
+  StringJoinAppend(aQuery, "&"_ns, aTokens,
+                   [](nsACString& dst, const QueryKeyValuePair& token) {
+                     dst.Append(token.key);
+                     dst.AppendLiteral("=");
+                     dst.Append(token.value);
+                   });
+}
+
+nsresult BackupDatabaseFile(nsIFile* aDBFile, const nsAString& aBackupFileName,
+                            nsIFile* aBackupParentDirectory, nsIFile** backup) {
+  nsresult rv;
+  nsCOMPtr<nsIFile> parentDir = aBackupParentDirectory;
+  if (!parentDir) {
+    // This argument is optional, and defaults to the same parent directory
+    // as the current file.
+    rv = aDBFile->GetParent(getter_AddRefs(parentDir));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsCOMPtr<nsIFile> backupDB;
+  rv = parentDir->Clone(getter_AddRefs(backupDB));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = backupDB->Append(aBackupFileName);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = backupDB->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoString fileName;
+  rv = backupDB->GetLeafName(fileName);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = backupDB->Remove(false);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  backupDB.forget(backup);
+  return aDBFile->CopyTo(parentDir, fileName);
+}
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/Helpers.h b/toolkit/components/places/Helpers.h
new file mode 100644
index 0000000000..6719fdded2
--- /dev/null
+++ b/toolkit/components/places/Helpers.h
@@ -0,0 +1,303 @@
+/* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_Helpers_h_
+#define mozilla_places_Helpers_h_
+
+/**
+ * This file contains helper classes used by various bits of Places code.
+ */
+
+#include "mozilla/storage.h"
+#include "nsIURI.h"
+#include "nsThreadUtils.h"
+#include "nsProxyRelease.h"
+#include "prtime.h"
+#include "mozilla/Telemetry.h"
+#include "mozIStorageStatementCallback.h"
+
+class nsIFile;
+
+namespace mozilla {
+namespace places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Asynchronous Statement Callback Helper
+
+class WeakAsyncStatementCallback : public mozIStorageStatementCallback {
+ public:
+  NS_DECL_MOZISTORAGESTATEMENTCALLBACK
+  WeakAsyncStatementCallback() = default;
+
+ protected:
+  virtual ~WeakAsyncStatementCallback() = default;
+};
+
+class AsyncStatementCallback : public WeakAsyncStatementCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  AsyncStatementCallback() = default;
+
+ protected:
+  virtual ~AsyncStatementCallback() = default;
+};
+
+/**
+ * Macros to use in place of NS_DECL_MOZISTORAGESTATEMENTCALLBACK to declare the
+ * methods this class assumes silent or notreached.
+ */
+#define NS_DECL_ASYNCSTATEMENTCALLBACK                     \
+  NS_IMETHOD HandleResult(mozIStorageResultSet*) override; \
+  NS_IMETHOD HandleCompletion(uint16_t) override;
+
+/**
+ * Utils to bind a specified URI (or URL) to a statement or binding params, at
+ * the specified index or name.
+ * @note URIs are always bound as UTF8.
+ */
+class URIBinder  // static
+{
+ public:
+  // Bind URI to statement by index.
+  static nsresult Bind(mozIStorageStatement* statement, int32_t index,
+                       nsIURI* aURI);
+  // Statement URLCString to statement by index.
+  static nsresult Bind(mozIStorageStatement* statement, int32_t index,
+                       const nsACString& aURLString);
+  // Bind URI to statement by name.
+  static nsresult Bind(mozIStorageStatement* statement, const nsACString& aName,
+                       nsIURI* aURI);
+  // Bind URLCString to statement by name.
+  static nsresult Bind(mozIStorageStatement* statement, const nsACString& aName,
+                       const nsACString& aURLString);
+  // Bind URI to params by index.
+  static nsresult Bind(mozIStorageBindingParams* aParams, int32_t index,
+                       nsIURI* aURI);
+  // Bind URLCString to params by index.
+  static nsresult Bind(mozIStorageBindingParams* aParams, int32_t index,
+                       const nsACString& aURLString);
+  // Bind URI to params by name.
+  static nsresult Bind(mozIStorageBindingParams* aParams,
+                       const nsACString& aName, nsIURI* aURI);
+  // Bind URLCString to params by name.
+  static nsresult Bind(mozIStorageBindingParams* aParams,
+                       const nsACString& aName, const nsACString& aURLString);
+};
+
+/**
+ * This extracts the hostname from the URI and reverses it in the
+ * form that we use (always ending with a "."). So
+ * "http://microsoft.com/" becomes "moc.tfosorcim."
+ *
+ * The idea behind this is that we can create an index over the items in
+ * the reversed host name column, and then query for as much or as little
+ * of the host name as we feel like.
+ *
+ * For example, the query "host >= 'gro.allizom.' AND host < 'gro.allizom/'
+ * Matches all host names ending in '.mozilla.org', including
+ * 'developer.mozilla.org' and just 'mozilla.org' (since we define all
+ * reversed host names to end in a period, even 'mozilla.org' matches).
+ * The important thing is that this operation uses the index. Any substring
+ * calls in a select statement (even if it's for the beginning of a string)
+ * will bypass any indices and will be slow).
+ *
+ * @param aURI
+ *        URI that contains spec to reverse
+ * @param aRevHost
+ *        Out parameter
+ */
+nsresult GetReversedHostname(nsIURI* aURI, nsString& aRevHost);
+
+/**
+ * Similar method to GetReversedHostName but for strings
+ */
+void GetReversedHostname(const nsString& aForward, nsString& aRevHost);
+
+/**
+ * Reverses a string.
+ *
+ * @param aInput
+ *        The string to be reversed
+ * @param aReversed
+ *        Output parameter will contain the reversed string
+ */
+void ReverseString(const nsString& aInput, nsString& aReversed);
+
+/**
+ * Generates an 12 character guid to be used by bookmark and history entries.
+ *
+ * @note This guid uses the characters a-z, A-Z, 0-9, '-', and '_'.
+ */
+nsresult GenerateGUID(nsACString& _guid);
+
+/**
+ * Determines if the string is a valid guid or not.
+ *
+ * @param aGUID
+ *        The guid to test.
+ * @return true if it is a valid guid, false otherwise.
+ */
+bool IsValidGUID(const nsACString& aGUID);
+
+/**
+ * Truncates the title if it's longer than TITLE_LENGTH_MAX.
+ *
+ * @param aTitle
+ *        The title to truncate (if necessary)
+ * @param aTrimmed
+ *        Output parameter to return the trimmed string
+ */
+void TruncateTitle(const nsACString& aTitle, nsACString& aTrimmed);
+
+/**
+ * Round down a PRTime value to milliseconds precision (...000).
+ *
+ * @param aTime
+ *        a PRTime value.
+ * @return aTime rounded down to milliseconds precision.
+ */
+PRTime RoundToMilliseconds(PRTime aTime);
+
+/**
+ * Round down PR_Now() to milliseconds precision.
+ *
+ * @return @see PR_Now, RoundToMilliseconds.
+ */
+PRTime RoundedPRNow();
+
+nsresult HashURL(const nsACString& aSpec, const nsACString& aMode,
+                 uint64_t* _hash);
+
+class QueryKeyValuePair final {
+ public:
+  QueryKeyValuePair(const nsACString& aKey, const nsACString& aValue) {
+    key = aKey;
+    value = aValue;
+  };
+
+  // QueryKeyValuePair
+  //
+  //                  01234567890
+  //    input : qwerty&key=value&qwerty
+  //                  ^   ^     ^
+  //          aKeyBegin   |     aPastEnd (may point to null terminator)
+  //                      aEquals
+  //
+  //    Special case: if aKeyBegin == aEquals, then there is only one string
+  //    and no equal sign, so we treat the entire thing as a key with no value
+
+  QueryKeyValuePair(const nsACString& aSource, int32_t aKeyBegin,
+                    int32_t aEquals, int32_t aPastEnd) {
+    if (aEquals == aKeyBegin) aEquals = aPastEnd;
+    key = Substring(aSource, aKeyBegin, aEquals - aKeyBegin);
+    if (aPastEnd - aEquals > 0)
+      value = Substring(aSource, aEquals + 1, aPastEnd - aEquals - 1);
+  }
+  nsCString key;
+  nsCString value;
+};
+
+/**
+ * Tokenizes a QueryString.
+ *
+ * @param aQuery The string to tokenize.
+ * @param aTokens The tokenized result.
+ */
+nsresult TokenizeQueryString(const nsACString& aQuery,
+                             nsTArray<QueryKeyValuePair>* aTokens);
+
+void TokensToQueryString(const nsTArray<QueryKeyValuePair>& aTokens,
+                         nsACString& aQuery);
+
+/**
+ * Copies the specified database file to the specified parent directory with
+ * the specified file name.  If the parent directory is not specified, it
+ * places the backup in the same directory as the current file.  This
+ * function ensures that the file being created is unique. This utility is meant
+ * to be used on database files with no open connections. Using this on database
+ * files with open connections may result in a corrupt backup file.
+ *
+ * @param aDBFile
+ *        The database file that will be backed up.
+ * @param aBackupFileName
+ *        The name of the new backup file to create.
+ * @param [optional] aBackupParentDirectory
+ *        The directory you'd like the backup file to be placed.
+ * @param backup
+ *        An outparam for the nsIFile pointing to the backup copy.
+ */
+nsresult BackupDatabaseFile(nsIFile* aDBFile, const nsAString& aBackupFileName,
+                            nsIFile* aBackupParentDirectory, nsIFile** backup);
+
+/**
+ * Used to finalize a statementCache on a specified thread.
+ */
+template <typename StatementType>
+class FinalizeStatementCacheProxy : public Runnable {
+ public:
+  /**
+   * Constructor.
+   *
+   * @param aStatementCache
+   *        The statementCache that should be finalized.
+   * @param aOwner
+   *        The object that owns the statement cache.  This runnable will hold
+   *        a strong reference to it so aStatementCache will not disappear from
+   *        under us.
+   */
+  FinalizeStatementCacheProxy(
+      mozilla::storage::StatementCache<StatementType>& aStatementCache,
+      nsISupports* aOwner)
+      : Runnable("places::FinalizeStatementCacheProxy"),
+        mStatementCache(aStatementCache),
+        mOwner(aOwner),
+        mCallingThread(do_GetCurrentThread()) {}
+
+  NS_IMETHOD Run() override {
+    mStatementCache.FinalizeStatements();
+    // Release the owner back on the calling thread.
+    NS_ProxyRelease("FinalizeStatementCacheProxy::mOwner", mCallingThread,
+                    mOwner.forget());
+    return NS_OK;
+  }
+
+ protected:
+  mozilla::storage::StatementCache<StatementType>& mStatementCache;
+  nsCOMPtr<nsISupports> mOwner;
+  nsCOMPtr<nsIThread> mCallingThread;
+};
+
+/**
+ * Determines if a visit should be marked as hidden given its transition type
+ * and whether or not it was a redirect.
+ *
+ * @param aIsRedirect
+ *        True if this visit was a redirect, false otherwise.
+ * @param aTransitionType
+ *        The transition type of the visit.
+ * @return true if this visit should be hidden.
+ */
+bool GetHiddenState(bool aIsRedirect, uint32_t aTransitionType);
+
+/**
+ * Used to notify a topic to system observers on async execute completion.
+ */
+class AsyncStatementTelemetryTimer : public AsyncStatementCallback {
+ public:
+  explicit AsyncStatementTelemetryTimer(Telemetry::HistogramID aHistogramId,
+                                        TimeStamp aStart = TimeStamp::Now())
+      : mHistogramId(aHistogramId), mStart(aStart) {}
+
+  NS_IMETHOD HandleCompletion(uint16_t aReason) override;
+
+ private:
+  const Telemetry::HistogramID mHistogramId;
+  const TimeStamp mStart;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_Helpers_h_
diff --git a/toolkit/components/places/History.cpp b/toolkit/components/places/History.cpp
new file mode 100644
index 0000000000..81cccdcb55
--- /dev/null
+++ b/toolkit/components/places/History.cpp
@@ -0,0 +1,2355 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Attributes.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/MemoryReporting.h"
+
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "nsXULAppAPI.h"
+
+#include "History.h"
+#include "nsNavHistory.h"
+#include "nsNavBookmarks.h"
+#include "Helpers.h"
+#include "PlaceInfo.h"
+#include "VisitInfo.h"
+#include "nsPlacesMacros.h"
+#include "NotifyRankingChanged.h"
+
+#include "mozilla/storage.h"
+#include "mozilla/dom/Link.h"
+#include "nsDocShellCID.h"
+#include "mozilla/Components.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsThreadUtils.h"
+#include "nsNetUtil.h"
+#include "nsIWidget.h"
+#include "nsIXPConnect.h"
+#include "nsIXULRuntime.h"
+#include "mozilla/Unused.h"
+#include "nsContentUtils.h"  // for nsAutoScriptBlocker
+#include "nsJSUtils.h"
+#include "nsStandardURL.h"
+#include "mozilla/ipc/URIUtils.h"
+#include "nsPrintfCString.h"
+#include "nsTHashtable.h"
+#include "jsapi.h"
+#include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject, JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_DefineElement, JS_GetElement, JS_GetProperty
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_places.h"
+#include "mozilla/dom/ContentProcessMessageManager.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/dom/PlacesVisit.h"
+#include "mozilla/dom/PlacesVisitTitle.h"
+#include "mozilla/dom/ScriptSettings.h"
+
+#include "nsIBrowserWindowTracker.h"
+#include "nsImportModule.h"
+#include "mozilla/StaticPrefs_browser.h"
+
+using namespace mozilla::dom;
+using namespace mozilla::ipc;
+
+namespace mozilla::places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// Global Defines
+
+// Observer event fired after a visit has been registered in the DB.
+#define URI_VISIT_SAVED "uri-visit-saved"
+
+#define DESTINATIONFILEURI_ANNO "downloads/destinationFileURI"_ns
+
+////////////////////////////////////////////////////////////////////////////////
+//// VisitData
+
+struct VisitData {
+  VisitData()
+      : placeId(0),
+        visitId(0),
+        hidden(true),
+        typed(false),
+        transitionType(UINT32_MAX),
+        visitTime(0),
+        frecency(-1),
+        lastVisitId(0),
+        lastVisitTime(0),
+        visitCount(0),
+        referrerVisitId(0),
+        titleChanged(false),
+        isUnrecoverableError(false),
+        useFrecencyRedirectBonus(false),
+        source(nsINavHistoryService::VISIT_SOURCE_ORGANIC),
+        triggeringPlaceId(0),
+        triggeringSponsoredURLVisitTimeMS(0),
+        bookmarked(false) {
+    guid.SetIsVoid(true);
+    title.SetIsVoid(true);
+    baseDomain.SetIsVoid(true);
+    triggeringSearchEngine.SetIsVoid(true);
+    triggeringSponsoredURL.SetIsVoid(true);
+    triggeringSponsoredURLBaseDomain.SetIsVoid(true);
+  }
+
+  explicit VisitData(nsIURI* aURI, nsIURI* aReferrer = nullptr)
+      : placeId(0),
+        visitId(0),
+        hidden(true),
+        typed(false),
+        transitionType(UINT32_MAX),
+        visitTime(0),
+        frecency(-1),
+        lastVisitId(0),
+        lastVisitTime(0),
+        visitCount(0),
+        referrerVisitId(0),
+        titleChanged(false),
+        isUnrecoverableError(false),
+        useFrecencyRedirectBonus(false),
+        source(nsINavHistoryService::VISIT_SOURCE_ORGANIC),
+        triggeringPlaceId(0),
+        triggeringSponsoredURLVisitTimeMS(0),
+        bookmarked(false) {
+    MOZ_ASSERT(aURI);
+    if (aURI) {
+      (void)aURI->GetSpec(spec);
+      (void)GetReversedHostname(aURI, revHost);
+    }
+    if (aReferrer) {
+      (void)aReferrer->GetSpec(referrerSpec);
+    }
+    guid.SetIsVoid(true);
+    title.SetIsVoid(true);
+    baseDomain.SetIsVoid(true);
+    triggeringSearchEngine.SetIsVoid(true);
+    triggeringSponsoredURL.SetIsVoid(true);
+    triggeringSponsoredURLBaseDomain.SetIsVoid(true);
+  }
+
+  /**
+   * Sets the transition type of the visit, as well as if it was typed.
+   *
+   * @param aTransitionType
+   *        The transition type constant to set.  Must be one of the
+   *        TRANSITION_ constants on nsINavHistoryService.
+   */
+  void SetTransitionType(uint32_t aTransitionType) {
+    typed = aTransitionType == nsINavHistoryService::TRANSITION_TYPED;
+    transitionType = aTransitionType;
+  }
+
+  int64_t placeId;
+  nsCString guid;
+  int64_t visitId;
+  nsCString spec;
+  nsCString baseDomain;
+  nsString revHost;
+  bool hidden;
+  bool typed;
+  uint32_t transitionType;
+  PRTime visitTime;
+  int32_t frecency;
+  int64_t lastVisitId;
+  PRTime lastVisitTime;
+  uint32_t visitCount;
+
+  /**
+   * Stores the title.  If this is empty (IsEmpty() returns true), then the
+   * title should be removed from the Place.  If the title is void (IsVoid()
+   * returns true), then no title has been set on this object, and titleChanged
+   * should remain false.
+   */
+  nsString title;
+
+  nsCString referrerSpec;
+  int64_t referrerVisitId;
+
+  // TODO bug 626836 hook up hidden and typed change tracking too!
+  bool titleChanged;
+
+  // Indicates whether the visit ended up in an unrecoverable error.
+  bool isUnrecoverableError;
+
+  // Whether to override the visit type bonus with a redirect bonus when
+  // calculating frecency on the most recent visit.
+  bool useFrecencyRedirectBonus;
+
+  uint16_t source;
+  nsCString triggeringSearchEngine;
+  int64_t triggeringPlaceId;
+  nsCString triggeringSponsoredURL;
+  nsCString triggeringSponsoredURLBaseDomain;
+  int64_t triggeringSponsoredURLVisitTimeMS;
+  bool bookmarked;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Anonymous Helpers
+
+namespace {
+
+/**
+ * Convert the given js value to a js array.
+ *
+ * @param [in] aValue
+ *        the JS value to convert.
+ * @param [in] aCtx
+ *        The JSContext for aValue.
+ * @param [out] _array
+ *        the JS array.
+ * @param [out] _arrayLength
+ *        _array's length.
+ */
+nsresult GetJSArrayFromJSValue(JS::Handle<JS::Value> aValue, JSContext* aCtx,
+                               JS::MutableHandle<JSObject*> _array,
+                               uint32_t* _arrayLength) {
+  if (aValue.isObjectOrNull()) {
+    JS::Rooted<JSObject*> val(aCtx, aValue.toObjectOrNull());
+    bool isArray;
+    if (!JS::IsArrayObject(aCtx, val, &isArray)) {
+      return NS_ERROR_UNEXPECTED;
+    }
+    if (isArray) {
+      _array.set(val);
+      (void)JS::GetArrayLength(aCtx, _array, _arrayLength);
+      NS_ENSURE_ARG(*_arrayLength > 0);
+      return NS_OK;
+    }
+  }
+
+  // Build a temporary array to store this one item so the code below can
+  // just loop.
+  *_arrayLength = 1;
+  _array.set(JS::NewArrayObject(aCtx, 0));
+  NS_ENSURE_TRUE(_array, NS_ERROR_OUT_OF_MEMORY);
+
+  bool rc = JS_DefineElement(aCtx, _array, 0, aValue, 0);
+  NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+  return NS_OK;
+}
+
+/**
+ * Attemps to convert a given js value to a nsIURI object.
+ * @param aCtx
+ *        The JSContext for aValue.
+ * @param aValue
+ *        The JS value to convert.
+ * @return the nsIURI object, or null if aValue is not a nsIURI object.
+ */
+already_AddRefed<nsIURI> GetJSValueAsURI(JSContext* aCtx,
+                                         const JS::Value& aValue) {
+  if (!aValue.isPrimitive()) {
+    nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+
+    nsCOMPtr<nsIXPConnectWrappedNative> wrappedObj;
+    JS::Rooted<JSObject*> obj(aCtx, aValue.toObjectOrNull());
+    nsresult rv =
+        xpc->GetWrappedNativeOfJSObject(aCtx, obj, getter_AddRefs(wrappedObj));
+    NS_ENSURE_SUCCESS(rv, nullptr);
+    nsCOMPtr<nsIURI> uri = do_QueryInterface(wrappedObj->Native());
+    return uri.forget();
+  }
+  return nullptr;
+}
+
+/**
+ * Obtains an nsIURI from the "uri" property of a JSObject.
+ *
+ * @param aCtx
+ *        The JSContext for aObject.
+ * @param aObject
+ *        The JSObject to get the URI from.
+ * @param aProperty
+ *        The name of the property to get the URI from.
+ * @return the URI if it exists.
+ */
+already_AddRefed<nsIURI> GetURIFromJSObject(JSContext* aCtx,
+                                            JS::Handle<JSObject*> aObject,
+                                            const char* aProperty) {
+  JS::Rooted<JS::Value> uriVal(aCtx);
+  bool rc = JS_GetProperty(aCtx, aObject, aProperty, &uriVal);
+  NS_ENSURE_TRUE(rc, nullptr);
+  return GetJSValueAsURI(aCtx, uriVal);
+}
+
+/**
+ * Attemps to convert a JS value to a string.
+ * @param aCtx
+ *        The JSContext for aObject.
+ * @param aValue
+ *        The JS value to convert.
+ * @param _string
+ *        The string to populate with the value, or set it to void.
+ */
+void GetJSValueAsString(JSContext* aCtx, const JS::Value& aValue,
+                        nsString& _string) {
+  if (aValue.isUndefined() || !(aValue.isNull() || aValue.isString())) {
+    _string.SetIsVoid(true);
+    return;
+  }
+
+  // |null| in JS maps to the empty string.
+  if (aValue.isNull()) {
+    _string.Truncate();
+    return;
+  }
+
+  if (!AssignJSString(aCtx, _string, aValue.toString())) {
+    _string.SetIsVoid(true);
+  }
+}
+
+/**
+ * Obtains the specified property of a JSObject.
+ *
+ * @param aCtx
+ *        The JSContext for aObject.
+ * @param aObject
+ *        The JSObject to get the string from.
+ * @param aProperty
+ *        The property to get the value from.
+ * @param _string
+ *        The string to populate with the value, or set it to void.
+ */
+void GetStringFromJSObject(JSContext* aCtx, JS::Handle<JSObject*> aObject,
+                           const char* aProperty, nsString& _string) {
+  JS::Rooted<JS::Value> val(aCtx);
+  bool rc = JS_GetProperty(aCtx, aObject, aProperty, &val);
+  if (!rc) {
+    _string.SetIsVoid(true);
+    return;
+  }
+  GetJSValueAsString(aCtx, val, _string);
+}
+
+/**
+ * Obtains the specified property of a JSObject.
+ *
+ * @param aCtx
+ *        The JSContext for aObject.
+ * @param aObject
+ *        The JSObject to get the int from.
+ * @param aProperty
+ *        The property to get the value from.
+ * @param _int
+ *        The integer to populate with the value on success.
+ */
+template <typename IntType>
+nsresult GetIntFromJSObject(JSContext* aCtx, JS::Handle<JSObject*> aObject,
+                            const char* aProperty, IntType* _int) {
+  JS::Rooted<JS::Value> value(aCtx);
+  bool rc = JS_GetProperty(aCtx, aObject, aProperty, &value);
+  NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+  if (value.isUndefined()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  NS_ENSURE_ARG(value.isPrimitive());
+  NS_ENSURE_ARG(value.isNumber());
+
+  double num;
+  rc = JS::ToNumber(aCtx, value, &num);
+  NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+  NS_ENSURE_ARG(IntType(num) == num);
+
+  *_int = IntType(num);
+  return NS_OK;
+}
+
+/**
+ * Obtains the specified property of a JSObject.
+ *
+ * @pre aArray must be an Array object.
+ *
+ * @param aCtx
+ *        The JSContext for aArray.
+ * @param aArray
+ *        The JSObject to get the object from.
+ * @param aIndex
+ *        The index to get the object from.
+ * @param objOut
+ *        Set to the JSObject pointer on success.
+ */
+nsresult GetJSObjectFromArray(JSContext* aCtx, JS::Handle<JSObject*> aArray,
+                              uint32_t aIndex,
+                              JS::MutableHandle<JSObject*> objOut) {
+  JS::Rooted<JS::Value> value(aCtx);
+  bool rc = JS_GetElement(aCtx, aArray, aIndex, &value);
+  NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+  NS_ENSURE_ARG(!value.isPrimitive());
+  objOut.set(&value.toObject());
+  return NS_OK;
+}
+
+}  // namespace
+
+class VisitedQuery final : public AsyncStatementCallback {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  static nsresult Start(nsIURI* aURI,
+                        History::ContentParentSet&& aContentProcessesToNotify) {
+    MOZ_ASSERT(aURI, "Null URI");
+    MOZ_ASSERT(XRE_IsParentProcess());
+
+    History* history = History::GetService();
+    NS_ENSURE_STATE(history);
+    RefPtr<VisitedQuery> query =
+        new VisitedQuery(aURI, std::move(aContentProcessesToNotify));
+    return history->QueueVisitedStatement(std::move(query));
+  }
+
+  static nsresult Start(nsIURI* aURI,
+                        mozIVisitedStatusCallback* aCallback = nullptr) {
+    MOZ_ASSERT(aURI, "Null URI");
+    MOZ_ASSERT(XRE_IsParentProcess());
+
+    nsMainThreadPtrHandle<mozIVisitedStatusCallback> callback(
+        new nsMainThreadPtrHolder<mozIVisitedStatusCallback>(
+            "mozIVisitedStatusCallback", aCallback));
+
+    History* history = History::GetService();
+    NS_ENSURE_STATE(history);
+    RefPtr<VisitedQuery> query = new VisitedQuery(aURI, callback);
+    return history->QueueVisitedStatement(std::move(query));
+  }
+
+  void Execute(mozIStorageAsyncStatement& aStatement) {
+    // Bind by index for performance.
+    nsresult rv = URIBinder::Bind(&aStatement, 0, mURI);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    nsCOMPtr<mozIStoragePendingStatement> handle;
+    rv = aStatement.ExecuteAsync(this, getter_AddRefs(handle));
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    Unused << rv;
+  }
+
+  NS_IMETHOD HandleResult(mozIStorageResultSet* aResults) override {
+    // If this method is called, we've gotten results, which means we have a
+    // visit.
+    mIsVisited = true;
+    return NS_OK;
+  }
+
+  NS_IMETHOD HandleError(mozIStorageError* aError) override {
+    // mIsVisited is already set to false, and that's the assumption we will
+    // make if an error occurred.
+    return NS_OK;
+  }
+
+  NS_IMETHOD HandleCompletion(uint16_t aReason) override {
+    if (aReason == mozIStorageStatementCallback::REASON_FINISHED) {
+      NotifyVisitedStatus();
+    }
+    return NS_OK;
+  }
+
+  void NotifyVisitedStatus() {
+    // If an external handling callback is provided, just notify through it.
+    if (mCallback) {
+      mCallback->IsVisited(mURI, mIsVisited);
+      return;
+    }
+
+    if (History* history = History::GetService()) {
+      auto status = mIsVisited ? IHistory::VisitedStatus::Visited
+                               : IHistory::VisitedStatus::Unvisited;
+      history->NotifyVisited(mURI, status, &mContentProcessesToNotify);
+    }
+  }
+
+ private:
+  explicit VisitedQuery(
+      nsIURI* aURI,
+      const nsMainThreadPtrHandle<mozIVisitedStatusCallback>& aCallback)
+      : mURI(aURI), mCallback(aCallback) {}
+
+  explicit VisitedQuery(nsIURI* aURI,
+                        History::ContentParentSet&& aContentProcessesToNotify)
+      : mURI(aURI),
+        mContentProcessesToNotify(std::move(aContentProcessesToNotify)) {}
+
+  ~VisitedQuery() = default;
+
+  nsCOMPtr<nsIURI> mURI;
+  nsMainThreadPtrHandle<mozIVisitedStatusCallback> mCallback;
+  History::ContentParentSet mContentProcessesToNotify;
+  bool mIsVisited = false;
+};
+
+NS_IMPL_ISUPPORTS_INHERITED0(VisitedQuery, AsyncStatementCallback)
+
+/**
+ * Notifies observers about a visit or an array of visits.
+ */
+class NotifyManyVisitsObservers : public Runnable {
+ public:
+  explicit NotifyManyVisitsObservers(const VisitData& aPlace)
+      : Runnable("places::NotifyManyVisitsObservers"),
+        mPlaces({aPlace}),
+        mHistory(History::GetService()) {}
+
+  explicit NotifyManyVisitsObservers(nsTArray<VisitData>&& aPlaces)
+      : Runnable("places::NotifyManyVisitsObservers"),
+        mPlaces(std::move(aPlaces)),
+        mHistory(History::GetService()) {}
+
+  nsresult NotifyVisit(nsNavHistory* aNavHistory,
+                       nsCOMPtr<nsIObserverService>& aObsService, PRTime aNow,
+                       nsIURI* aURI, const VisitData& aPlace) {
+    if (aObsService) {
+      DebugOnly<nsresult> rv =
+          aObsService->NotifyObservers(aURI, URI_VISIT_SAVED, nullptr);
+      NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Could not notify observers");
+    }
+
+    if (aNow - aPlace.visitTime < RECENTLY_VISITED_URIS_MAX_AGE) {
+      mHistory->AppendToRecentlyVisitedURIs(aURI, aPlace.hidden);
+    }
+    mHistory->NotifyVisited(aURI, IHistory::VisitedStatus::Visited);
+
+    aNavHistory->UpdateDaysOfHistory(aPlace.visitTime);
+
+    return NS_OK;
+  }
+
+  void AddPlaceForNotify(const VisitData& aPlace,
+                         Sequence<OwningNonNull<PlacesEvent>>& aEvents) {
+    if (aPlace.transitionType == nsINavHistoryService::TRANSITION_EMBED) {
+      return;
+    }
+
+    RefPtr<PlacesVisit> visitEvent = new PlacesVisit();
+    visitEvent->mVisitId = aPlace.visitId;
+    visitEvent->mUrl.Assign(NS_ConvertUTF8toUTF16(aPlace.spec));
+    visitEvent->mVisitTime = aPlace.visitTime / 1000;
+    visitEvent->mReferringVisitId = aPlace.referrerVisitId;
+    visitEvent->mTransitionType = aPlace.transitionType;
+    visitEvent->mPageGuid.Assign(aPlace.guid);
+    visitEvent->mFrecency = aPlace.frecency;
+    visitEvent->mHidden = aPlace.hidden;
+    visitEvent->mVisitCount = aPlace.visitCount + 1;  // Add current visit
+    visitEvent->mTypedCount = static_cast<uint32_t>(aPlace.typed);
+    visitEvent->mLastKnownTitle.Assign(aPlace.title);
+
+    bool success = !!aEvents.AppendElement(visitEvent.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+
+    if (aPlace.titleChanged) {
+      RefPtr<PlacesVisitTitle> titleEvent = new PlacesVisitTitle();
+      titleEvent->mUrl.Assign(NS_ConvertUTF8toUTF16(aPlace.spec));
+      titleEvent->mPageGuid.Assign(aPlace.guid);
+      titleEvent->mTitle.Assign(aPlace.title);
+      bool success = !!aEvents.AppendElement(titleEvent.forget(), fallible);
+      MOZ_RELEASE_ASSERT(success);
+    }
+  }
+
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is marked
+  // MOZ_CAN_RUN_SCRIPT.  See bug 1535398.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+
+    // We are in the main thread, no need to lock.
+    if (mHistory->IsShuttingDown()) {
+      // If we are shutting down, we cannot notify the observers.
+      return NS_OK;
+    }
+
+    nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+    if (!navHistory) {
+      NS_WARNING(
+          "Trying to notify visits observers but cannot get the history "
+          "service!");
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIObserverService> obsService =
+        mozilla::services::GetObserverService();
+
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    PRTime now = PR_Now();
+    for (uint32_t i = 0; i < mPlaces.Length(); ++i) {
+      nsCOMPtr<nsIURI> uri;
+      if (NS_WARN_IF(
+              NS_FAILED(NS_NewURI(getter_AddRefs(uri), mPlaces[i].spec)))) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      AddPlaceForNotify(mPlaces[i], events);
+
+      nsresult rv = NotifyVisit(navHistory, obsService, now, uri, mPlaces[i]);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    if (events.Length() > 0) {
+      PlacesObservers::NotifyListeners(events);
+    }
+
+    return NS_OK;
+  }
+
+ private:
+  AutoTArray<VisitData, 1> mPlaces;
+  RefPtr<History> mHistory;
+};
+
+/**
+ * Notifies observers about a pages title changing.
+ */
+class NotifyTitleObservers : public Runnable {
+ public:
+  /**
+   * Notifies observers on the main thread.
+   *
+   * @param aSpec
+   *        The spec of the URI to notify about.
+   * @param aTitle
+   *        The new title to notify about.
+   */
+  NotifyTitleObservers(const nsCString& aSpec, const nsString& aTitle,
+                       const nsCString& aGUID)
+      : Runnable("places::NotifyTitleObservers"),
+        mSpec(aSpec),
+        mTitle(aTitle),
+        mGUID(aGUID) {}
+
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is marked
+  // MOZ_CAN_RUN_SCRIPT.  See bug 1535398.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+
+    RefPtr<PlacesVisitTitle> titleEvent = new PlacesVisitTitle();
+    titleEvent->mUrl.Assign(NS_ConvertUTF8toUTF16(mSpec));
+    titleEvent->mPageGuid.Assign(mGUID);
+    titleEvent->mTitle.Assign(mTitle);
+
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    bool success = !!events.AppendElement(titleEvent.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+
+    PlacesObservers::NotifyListeners(events);
+
+    return NS_OK;
+  }
+
+ private:
+  const nsCString mSpec;
+  const nsString mTitle;
+  const nsCString mGUID;
+};
+
+/**
+ * Helper class for methods which notify their callers through the
+ * mozIVisitInfoCallback interface.
+ */
+class NotifyPlaceInfoCallback : public Runnable {
+ public:
+  NotifyPlaceInfoCallback(
+      const nsMainThreadPtrHandle<mozIVisitInfoCallback>& aCallback,
+      const VisitData& aPlace, bool aIsSingleVisit, nsresult aResult)
+      : Runnable("places::NotifyPlaceInfoCallback"),
+        mCallback(aCallback),
+        mPlace(aPlace),
+        mResult(aResult),
+        mIsSingleVisit(aIsSingleVisit) {
+    MOZ_ASSERT(aCallback, "Must pass a non-null callback!");
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+
+    bool hasValidURIs = true;
+    nsCOMPtr<nsIURI> referrerURI;
+    if (!mPlace.referrerSpec.IsEmpty()) {
+      hasValidURIs = !NS_WARN_IF(NS_FAILED(
+          NS_NewURI(getter_AddRefs(referrerURI), mPlace.referrerSpec)));
+    }
+
+    nsCOMPtr<nsIURI> uri;
+    hasValidURIs =
+        hasValidURIs &&
+        !NS_WARN_IF(NS_FAILED(NS_NewURI(getter_AddRefs(uri), mPlace.spec)));
+
+    nsCOMPtr<mozIPlaceInfo> place;
+    if (mIsSingleVisit) {
+      nsCOMPtr<mozIVisitInfo> visit =
+          new VisitInfo(mPlace.visitId, mPlace.visitTime, mPlace.transitionType,
+                        referrerURI.forget());
+      PlaceInfo::VisitsArray visits;
+      (void)visits.AppendElement(visit);
+
+      // The frecency isn't exposed because it may not reflect the updated value
+      // in the case of InsertVisitedURIs.
+      place = new PlaceInfo(mPlace.placeId, mPlace.guid, uri.forget(),
+                            mPlace.title, -1, visits);
+    } else {
+      // Same as above.
+      place = new PlaceInfo(mPlace.placeId, mPlace.guid, uri.forget(),
+                            mPlace.title, -1);
+    }
+
+    if (NS_SUCCEEDED(mResult) && hasValidURIs) {
+      (void)mCallback->HandleResult(place);
+    } else {
+      (void)mCallback->HandleError(mResult, place);
+    }
+
+    return NS_OK;
+  }
+
+ private:
+  nsMainThreadPtrHandle<mozIVisitInfoCallback> mCallback;
+  VisitData mPlace;
+  const nsresult mResult;
+  bool mIsSingleVisit;
+};
+
+/**
+ * Notifies a callback object when the operation is complete.
+ */
+class NotifyCompletion : public Runnable {
+ public:
+  explicit NotifyCompletion(
+      const nsMainThreadPtrHandle<mozIVisitInfoCallback>& aCallback,
+      uint32_t aUpdatedCount = 0)
+      : Runnable("places::NotifyCompletion"),
+        mCallback(aCallback),
+        mUpdatedCount(aUpdatedCount) {
+    MOZ_ASSERT(aCallback, "Must pass a non-null callback!");
+  }
+
+  NS_IMETHOD Run() override {
+    if (NS_IsMainThread()) {
+      (void)mCallback->HandleCompletion(mUpdatedCount);
+    } else {
+      (void)NS_DispatchToMainThread(this);
+    }
+    return NS_OK;
+  }
+
+ private:
+  nsMainThreadPtrHandle<mozIVisitInfoCallback> mCallback;
+  uint32_t mUpdatedCount;
+};
+
+/**
+ * Checks to see if we can add aURI to history, and dispatches an error to
+ * aCallback (if provided) if we cannot.
+ *
+ * @param aURI
+ *        The URI to check.
+ * @param [optional] aGUID
+ *        The guid of the URI to check.  This is passed back to the callback.
+ * @param [optional] aCallback
+ *        The callback to notify if the URI cannot be added to history.
+ * @return true if the URI can be added to history, false otherwise.
+ */
+bool CanAddURI(nsIURI* aURI, const nsCString& aGUID = ""_ns,
+               mozIVisitInfoCallback* aCallback = nullptr) {
+  MOZ_ASSERT(NS_IsMainThread());
+  nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(navHistory, false);
+
+  bool canAdd;
+  nsresult rv = navHistory->CanAddURI(aURI, &canAdd);
+  if (NS_SUCCEEDED(rv) && canAdd) {
+    return true;
+  };
+
+  // We cannot add the URI.  Notify the callback, if we were given one.
+  if (aCallback) {
+    VisitData place(aURI);
+    place.guid = aGUID;
+    nsMainThreadPtrHandle<mozIVisitInfoCallback> callback(
+        new nsMainThreadPtrHolder<mozIVisitInfoCallback>(
+            "mozIVisitInfoCallback", aCallback));
+    nsCOMPtr<nsIRunnable> event = new NotifyPlaceInfoCallback(
+        callback, place, true, NS_ERROR_INVALID_ARG);
+    (void)NS_DispatchToMainThread(event);
+  }
+
+  return false;
+}
+
+/**
+ * Adds a visit to the database.
+ */
+class InsertVisitedURIs final : public Runnable {
+ public:
+  /**
+   * Adds a visit to the database asynchronously.
+   *
+   * @param aConnection
+   *        The database connection to use for these operations.
+   * @param aPlaces
+   *        The locations to record visits.
+   * @param [optional] aCallback
+   *        The callback to notify about the visit.
+   */
+  static nsresult Start(mozIStorageConnection* aConnection,
+                        nsTArray<VisitData>&& aPlaces,
+                        mozIVisitInfoCallback* aCallback = nullptr,
+                        uint32_t aInitialUpdatedCount = 0) {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+    MOZ_ASSERT(aPlaces.Length() > 0, "Must pass a non-empty array!");
+
+    // Make sure nsNavHistory service is up before proceeding:
+    nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+    MOZ_ASSERT(navHistory, "Could not get nsNavHistory?!");
+    if (!navHistory) {
+      return NS_ERROR_FAILURE;
+    }
+
+    nsMainThreadPtrHandle<mozIVisitInfoCallback> callback(
+        new nsMainThreadPtrHolder<mozIVisitInfoCallback>(
+            "mozIVisitInfoCallback", aCallback));
+    bool ignoreErrors = false, ignoreResults = false;
+    if (aCallback) {
+      // We ignore errors from either of these methods in case old JS consumers
+      // don't implement them (in which case they will get error/result
+      // notifications as normal).
+      Unused << aCallback->GetIgnoreErrors(&ignoreErrors);
+      Unused << aCallback->GetIgnoreResults(&ignoreResults);
+    }
+    RefPtr<InsertVisitedURIs> event = new InsertVisitedURIs(
+        aConnection, std::move(aPlaces), callback, ignoreErrors, ignoreResults,
+        aInitialUpdatedCount);
+
+    // Get the target thread, and then start the work!
+    nsCOMPtr<nsIEventTarget> target = do_GetInterface(aConnection);
+    NS_ENSURE_TRUE(target, NS_ERROR_UNEXPECTED);
+    nsresult rv = target->Dispatch(event, NS_DISPATCH_NORMAL);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return NS_OK;
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread(),
+               "This should not be called on the main thread");
+
+    // The inner run method may bail out at any point, so we ensure we do
+    // whatever we can and then notify the main thread we're done.
+    nsresult rv = InnerRun();
+
+    if (!!mCallback) {
+      NS_DispatchToMainThread(
+          new NotifyCompletion(mCallback, mSuccessfulUpdatedCount));
+    }
+    return rv;
+  }
+
+  nsresult InnerRun() {
+    MOZ_ASSERT(!NS_IsMainThread());
+    // Prevent Shutdown() from proceeding while this is running.
+    MutexAutoLock lockedScope(mHistory->mBlockShutdownMutex);
+    // Check if we were already shutting down.
+    if (mHistory->IsShuttingDown()) {
+      return NS_OK;
+    }
+
+    mozStorageTransaction transaction(
+        mDBConn, false, mozIStorageConnection::TRANSACTION_IMMEDIATE);
+
+    // XXX Handle the error, bug 1696133.
+    Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+    const VisitData* lastFetchedPlace = nullptr;
+    uint32_t lastFetchedVisitCount = 0;
+    bool shouldChunkNotifications = mPlaces.Length() > NOTIFY_VISITS_CHUNK_SIZE;
+    nsTArray<VisitData> notificationChunk;
+    if (shouldChunkNotifications) {
+      notificationChunk.SetCapacity(NOTIFY_VISITS_CHUNK_SIZE);
+    }
+
+    // This is an optimization for frecency updating, if all the entries point
+    // to the same URL (inserting multiple visits for the same url), then we can
+    // update frecency once at the end of the loop. Otherwise, if there's
+    // multiple pages, we'll delay frecency recalculation to a later time.
+    bool shouldUpdateFrecency = false;
+
+    for (nsTArray<VisitData>::size_type i = 0; i < mPlaces.Length(); i++) {
+      VisitData& place = mPlaces.ElementAt(i);
+
+      if (i == 0) {
+        // isUnrecoverableError can only be defined when this is invoked by
+        // VisitURI, to insert a single visit. When it's defined, the page
+        // will be hidden, thus it's not worth updating.
+        shouldUpdateFrecency = !place.isUnrecoverableError;
+      } else if (shouldUpdateFrecency &&
+                 (!place.spec.Equals(mPlaces.ElementAt(i - 1).spec))) {
+        // We have multiple entries with different URLs, delay recalculation.
+        // A SQL trigger will set recalc_frecency automatically when a visit
+        // is added.
+        shouldUpdateFrecency = false;
+      }
+      // Fetching from the database can overwrite this information, so save it
+      // apart.
+      bool typed = place.typed;
+      bool hidden = place.hidden;
+
+      // We can avoid a database lookup if it's the same place as the last
+      // visit we added.
+      bool known =
+          lastFetchedPlace && lastFetchedPlace->spec.Equals(place.spec);
+      if (!known) {
+        nsresult rv = mHistory->FetchPageInfo(place, &known);
+        if (NS_FAILED(rv)) {
+          if (!!mCallback && !mIgnoreErrors) {
+            nsCOMPtr<nsIRunnable> event =
+                new NotifyPlaceInfoCallback(mCallback, place, true, rv);
+            return NS_DispatchToMainThread(event);
+          }
+          return NS_OK;
+        }
+        lastFetchedPlace = &mPlaces.ElementAt(i);
+        lastFetchedVisitCount = lastFetchedPlace->visitCount;
+      } else {
+        // Copy over the data from the already known place.
+        place.placeId = lastFetchedPlace->placeId;
+        place.guid = lastFetchedPlace->guid;
+        place.lastVisitId = lastFetchedPlace->visitId;
+        place.lastVisitTime = lastFetchedPlace->visitTime;
+        if (!place.title.IsVoid()) {
+          place.titleChanged = !lastFetchedPlace->title.Equals(place.title);
+        }
+        place.frecency = lastFetchedPlace->frecency;
+        // Add one visit for the previous loop.
+        place.visitCount = ++lastFetchedVisitCount;
+      }
+
+      // If any transition is typed, ensure the page is marked as typed.
+      if (typed != lastFetchedPlace->typed) {
+        place.typed = true;
+      }
+
+      // If any transition is visible, ensure the page is marked as visible.
+      if (hidden != lastFetchedPlace->hidden) {
+        place.hidden = false;
+      }
+
+      FetchReferrerInfo(place);
+      UpdateVisitSource(place, mHistory);
+
+      nsresult rv = DoDatabaseInserts(known, place);
+      if (!!mCallback) {
+        // Check if consumers wanted to be notified about success/failure,
+        // depending on whether this action succeeded or not.
+        if ((NS_SUCCEEDED(rv) && !mIgnoreResults) ||
+            (NS_FAILED(rv) && !mIgnoreErrors)) {
+          nsCOMPtr<nsIRunnable> event =
+              new NotifyPlaceInfoCallback(mCallback, place, true, rv);
+          nsresult rv2 = NS_DispatchToMainThread(event);
+          NS_ENSURE_SUCCESS(rv2, rv2);
+        }
+      }
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      if (shouldChunkNotifications) {
+        int32_t numRemaining = (int32_t)(mPlaces.Length() - (i + 1));
+        notificationChunk.AppendElement(place);
+        if (notificationChunk.Length() == NOTIFY_VISITS_CHUNK_SIZE ||
+            numRemaining == 0) {
+          nsCOMPtr<nsIRunnable> event =
+              new NotifyManyVisitsObservers(std::move(notificationChunk));
+          rv = NS_DispatchToMainThread(event);
+          NS_ENSURE_SUCCESS(rv, rv);
+
+          int32_t nextCapacity =
+              std::min(NOTIFY_VISITS_CHUNK_SIZE, numRemaining);
+          notificationChunk.SetCapacity(nextCapacity);
+        }
+      }
+
+      // If we get here, we must have been successful adding/updating this
+      // visit/place, so update the count:
+      mSuccessfulUpdatedCount++;
+    }
+
+    if (shouldUpdateFrecency) {
+      VisitData& place = mPlaces.ElementAt(0);
+      if (NS_SUCCEEDED(UpdateFrecency(
+              place.placeId,
+              place.useFrecencyRedirectBonus && mPlaces.Length() == 1))) {
+        // Notifying a new visit should be sufficient to know that frecency
+        // changed, but since historically we notified a frecency change, for
+        // now we'll continue doing it, and re-evaluate in the future.
+        NS_DispatchToMainThread(new NotifyRankingChanged());
+      }
+    }
+
+    nsresult rv = transaction.Commit();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // If we don't need to chunk the notifications, just notify using the
+    // original mPlaces array.
+    if (!shouldChunkNotifications) {
+      nsCOMPtr<nsIRunnable> event =
+          new NotifyManyVisitsObservers(std::move(mPlaces));
+      rv = NS_DispatchToMainThread(event);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    return NS_OK;
+  }
+
+ private:
+  InsertVisitedURIs(
+      mozIStorageConnection* aConnection, nsTArray<VisitData>&& aPlaces,
+      const nsMainThreadPtrHandle<mozIVisitInfoCallback>& aCallback,
+      bool aIgnoreErrors, bool aIgnoreResults, uint32_t aInitialUpdatedCount)
+      : Runnable("places::InsertVisitedURIs"),
+        mDBConn(aConnection),
+        mPlaces(std::move(aPlaces)),
+        mCallback(aCallback),
+        mIgnoreErrors(aIgnoreErrors),
+        mIgnoreResults(aIgnoreResults),
+        mSuccessfulUpdatedCount(aInitialUpdatedCount),
+        mHistory(History::GetService()) {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+
+#ifdef DEBUG
+    for (nsTArray<VisitData>::size_type i = 0; i < mPlaces.Length(); i++) {
+      nsCOMPtr<nsIURI> uri;
+      MOZ_ASSERT(NS_SUCCEEDED(NS_NewURI(getter_AddRefs(uri), mPlaces[i].spec)));
+      MOZ_ASSERT(CanAddURI(uri),
+                 "Passed a VisitData with a URI we cannot add to history!");
+    }
+#endif
+  }
+
+  /**
+   * Inserts or updates the entry in moz_places for this visit, adds the visit,
+   * and updates the frecency of the place.
+   *
+   * @param {boolean} aKnown
+   *        True if we already have an entry for this place in moz_places, false
+   *        otherwise.
+   * @param {VisitData} aPlace
+   *        The place we are adding a visit for.
+   */
+  nsresult DoDatabaseInserts(bool aKnown, VisitData& aPlace) {
+    MOZ_ASSERT(!NS_IsMainThread(),
+               "This should not be called on the main thread");
+
+    // If the page was in moz_places, we need to update the entry.
+    nsresult rv;
+    if (aKnown) {
+      rv = mHistory->UpdatePlace(aPlace);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+    // Otherwise, the page was not in moz_places, so now we have to add it.
+    else {
+      rv = mHistory->InsertPlace(aPlace);
+      NS_ENSURE_SUCCESS(rv, rv);
+      aPlace.placeId = nsNavHistory::sLastInsertedPlaceId;
+    }
+    MOZ_ASSERT(aPlace.placeId > 0);
+
+    rv = AddVisit(aPlace);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Adding a visit sets the recalculation flags through a trigger, but for
+    // error pages we don't want that, because recalculation considers this a
+    // normal successful visit. In the future we should store the error state
+    // along with the visit, so that recalculation can do a better job and
+    // we can remove this workaround update. See Bug 1842008.
+    if (aPlace.isUnrecoverableError) {
+      nsCOMPtr<mozIStorageStatement> stmt = mHistory->GetStatement(
+          "UPDATE moz_places "
+          "SET recalc_frecency = 0, recalc_alt_frecency = 0 "
+          "WHERE id = :page_id");
+      NS_ENSURE_STATE(stmt);
+      mozStorageStatementScoper scoper(stmt);
+      rv = stmt->BindInt64ByName("page_id"_ns, aPlace.placeId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    return NS_OK;
+  }
+
+  /**
+   * Fetches information about a referrer for aPlace if it was a recent
+   * visit or not.
+   *
+   * @param aPlace
+   *        The VisitData for the visit we will eventually add.
+   *
+   */
+  void FetchReferrerInfo(VisitData& aPlace) {
+    if (aPlace.referrerSpec.IsEmpty()) {
+      return;
+    }
+
+    VisitData referrer;
+    referrer.spec = aPlace.referrerSpec;
+    // If the referrer is the same as the page, we don't need to fetch it.
+    if (aPlace.referrerSpec.Equals(aPlace.spec)) {
+      referrer = aPlace;
+      // The page last visit id is also the referrer visit id.
+      aPlace.referrerVisitId = aPlace.lastVisitId;
+    } else {
+      bool exists = false;
+      if (NS_SUCCEEDED(mHistory->FetchPageInfo(referrer, &exists)) && exists) {
+        // Copy the referrer last visit id.
+        aPlace.referrerVisitId = referrer.lastVisitId;
+      }
+    }
+
+    // Check if the page has effectively been visited recently, otherwise
+    // discard the referrer info.
+    if (!aPlace.referrerVisitId || !referrer.lastVisitTime ||
+        aPlace.visitTime - referrer.lastVisitTime > RECENT_EVENT_THRESHOLD) {
+      // We will not be using the referrer data.
+      aPlace.referrerSpec.Truncate();
+      aPlace.referrerVisitId = 0;
+    }
+  }
+
+  /**
+   * Adds a visit for _place and updates it with the right visit id.
+   *
+   * @param _place
+   *        The VisitData for the place we need to know visit information about.
+   */
+  nsresult AddVisit(VisitData& _place) {
+    MOZ_ASSERT(_place.placeId > 0);
+
+    nsresult rv;
+    nsCOMPtr<mozIStorageStatement> stmt;
+    stmt = mHistory->GetStatement(
+        "INSERT INTO moz_historyvisits "
+        "(from_visit, place_id, visit_date, visit_type, session, source, "
+        "triggeringPlaceId) "
+        "VALUES (:from_visit, :page_id, :visit_date, :visit_type, 0, :source, "
+        ":triggeringPlaceId) ");
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+
+    rv = stmt->BindInt64ByName("page_id"_ns, _place.placeId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindInt64ByName("from_visit"_ns, _place.referrerVisitId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindInt64ByName("visit_date"_ns, _place.visitTime);
+    NS_ENSURE_SUCCESS(rv, rv);
+    uint32_t transitionType = _place.transitionType;
+    MOZ_ASSERT(transitionType >= nsINavHistoryService::TRANSITION_LINK &&
+                   transitionType <= nsINavHistoryService::TRANSITION_RELOAD,
+               "Invalid transition type!");
+    rv = stmt->BindInt32ByName("visit_type"_ns, (int32_t)transitionType);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindInt32ByName("source"_ns, _place.source);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (_place.triggeringPlaceId != 0) {
+      rv = stmt->BindInt64ByName("triggeringPlaceId"_ns,
+                                 _place.triggeringPlaceId);
+    } else {
+      rv = stmt->BindNullByName("triggeringPlaceId"_ns);
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    _place.visitId = nsNavHistory::sLastInsertedVisitId;
+    MOZ_ASSERT(_place.visitId > 0);
+
+    return NS_OK;
+  }
+
+  /**
+   * Updates the frecency, and possibly the hidden-ness of aPlace.
+   *
+   * @param aPlace
+   *        The VisitData for the place we want to update.
+   */
+  nsresult UpdateFrecency(const int64_t aPlaceId, bool aIsRedirect) {
+    nsresult rv;
+    {  // First, set our frecency to the proper value.
+      nsCOMPtr<mozIStorageStatement> stmt = mHistory->GetStatement(
+          "UPDATE moz_places "
+          "SET frecency = CALCULATE_FRECENCY(:page_id, :redirect) "
+          "WHERE id = :page_id");
+      NS_ENSURE_STATE(stmt);
+      mozStorageStatementScoper scoper(stmt);
+
+      rv = stmt->BindInt64ByName("page_id"_ns, aPlaceId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->BindInt32ByName("redirect"_ns, aIsRedirect);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    if (StaticPrefs::
+            places_frecency_pages_alternative_featureGate_AtStartup()) {
+      nsCOMPtr<mozIStorageStatement> stmt = mHistory->GetStatement(
+          "UPDATE moz_places "
+          "SET alt_frecency = CALCULATE_ALT_FRECENCY(id, :redirect), "
+          "recalc_alt_frecency = 0 "
+          "WHERE id = :page_id");
+      NS_ENSURE_STATE(stmt);
+      mozStorageStatementScoper scoper(stmt);
+      rv = stmt->BindInt64ByName("page_id"_ns, aPlaceId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->BindInt32ByName("redirect"_ns, aIsRedirect);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    return NS_OK;
+  }
+
+  nsresult UpdateVisitSource(VisitData& aPlace, History* aHistory) {
+    if (aPlace.bookmarked) {
+      aPlace.source = nsINavHistoryService::VISIT_SOURCE_BOOKMARKED;
+    } else if (!aPlace.triggeringSearchEngine.IsEmpty()) {
+      aPlace.source = nsINavHistoryService::VISIT_SOURCE_SEARCHED;
+    } else {
+      aPlace.source = nsINavHistoryService::VISIT_SOURCE_ORGANIC;
+    }
+
+    if (aPlace.triggeringSponsoredURL.IsEmpty()) {
+      // No triggeringSponsoredURL.
+      return NS_OK;
+    }
+
+    if ((aPlace.visitTime -
+         aPlace.triggeringSponsoredURLVisitTimeMS * PR_USEC_PER_MSEC) >
+        StaticPrefs::browser_places_sponsoredSession_timeoutSecs() *
+            PR_USEC_PER_SEC) {
+      // Sponsored session timeout.
+      return NS_OK;
+    }
+
+    if (aPlace.spec.Equals(aPlace.triggeringSponsoredURL)) {
+      // This place is the triggeringSponsoredURL.
+      aPlace.source = nsINavHistoryService::VISIT_SOURCE_SPONSORED;
+      return NS_OK;
+    }
+
+    if (!aPlace.baseDomain.Equals(aPlace.triggeringSponsoredURLBaseDomain)) {
+      // The base domain is not same.
+      return NS_OK;
+    }
+
+    nsCOMPtr<mozIStorageStatement> stmt;
+    stmt = aHistory->GetStatement(
+        "SELECT id FROM moz_places h "
+        "WHERE url_hash = hash(:url) AND url = :url");
+    NS_ENSURE_STATE(stmt);
+    nsresult rv =
+        URIBinder::Bind(stmt, "url"_ns, aPlace.triggeringSponsoredURL);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    mozStorageStatementScoper scoper(stmt);
+
+    bool exists;
+    rv = stmt->ExecuteStep(&exists);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (exists) {
+      rv = stmt->GetInt64(0, &aPlace.triggeringPlaceId);
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      Telemetry::ScalarAdd(
+          Telemetry::ScalarID::PLACES_SPONSORED_VISIT_NO_TRIGGERING_URL, 1);
+    }
+
+    aPlace.source = nsINavHistoryService::VISIT_SOURCE_SPONSORED;
+
+    return NS_OK;
+  }
+
+  mozIStorageConnection* mDBConn;
+
+  nsTArray<VisitData> mPlaces;
+
+  nsMainThreadPtrHandle<mozIVisitInfoCallback> mCallback;
+
+  bool mIgnoreErrors;
+
+  bool mIgnoreResults;
+
+  uint32_t mSuccessfulUpdatedCount;
+
+  /**
+   * Strong reference to the History object because we do not want it to
+   * disappear out from under us.
+   */
+  RefPtr<History> mHistory;
+};
+
+/**
+ * Sets the page title for a page in moz_places (if necessary).
+ */
+class SetPageTitle : public Runnable {
+ public:
+  /**
+   * Sets a pages title in the database asynchronously.
+   *
+   * @param aConnection
+   *        The database connection to use for this operation.
+   * @param aURI
+   *        The URI to set the page title on.
+   * @param aTitle
+   *        The title to set for the page, if the page exists.
+   */
+  static nsresult Start(mozIStorageConnection* aConnection, nsIURI* aURI,
+                        const nsAString& aTitle) {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+    MOZ_ASSERT(aURI, "Must pass a non-null URI object!");
+
+    nsCString spec;
+    nsresult rv = aURI->GetSpec(spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    RefPtr<SetPageTitle> event = new SetPageTitle(spec, aTitle);
+
+    // Get the target thread, and then start the work!
+    nsCOMPtr<nsIEventTarget> target = do_GetInterface(aConnection);
+    NS_ENSURE_TRUE(target, NS_ERROR_UNEXPECTED);
+    rv = target->Dispatch(event, NS_DISPATCH_NORMAL);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return NS_OK;
+  }
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!NS_IsMainThread(),
+               "This should not be called on the main thread");
+
+    // First, see if the page exists in the database (we'll need its id later).
+    bool exists;
+    nsresult rv = mHistory->FetchPageInfo(mPlace, &exists);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (!exists || !mPlace.titleChanged) {
+      // We have no record of this page, or we have no title change, so there
+      // is no need to do any further work.
+      return NS_OK;
+    }
+
+    MOZ_ASSERT(mPlace.placeId > 0, "We somehow have an invalid place id here!");
+
+    // Now we can update our database record.
+    nsCOMPtr<mozIStorageStatement> stmt = mHistory->GetStatement(
+        "UPDATE moz_places "
+        "SET title = :page_title "
+        "WHERE id = :page_id ");
+    NS_ENSURE_STATE(stmt);
+
+    {
+      mozStorageStatementScoper scoper(stmt);
+      rv = stmt->BindInt64ByName("page_id"_ns, mPlace.placeId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Empty strings should clear the title, just like
+      // nsNavHistory::SetPageTitle.
+      if (mPlace.title.IsEmpty()) {
+        rv = stmt->BindNullByName("page_title"_ns);
+      } else {
+        rv = stmt->BindStringByName("page_title"_ns,
+                                    StringHead(mPlace.title, TITLE_LENGTH_MAX));
+      }
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->Execute();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    nsCOMPtr<nsIRunnable> event =
+        new NotifyTitleObservers(mPlace.spec, mPlace.title, mPlace.guid);
+    rv = NS_DispatchToMainThread(event);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return NS_OK;
+  }
+
+ private:
+  SetPageTitle(const nsCString& aSpec, const nsAString& aTitle)
+      : Runnable("places::SetPageTitle"), mHistory(History::GetService()) {
+    mPlace.spec = aSpec;
+    mPlace.title = aTitle;
+  }
+
+  VisitData mPlace;
+
+  /**
+   * Strong reference to the History object because we do not want it to
+   * disappear out from under us.
+   */
+  RefPtr<History> mHistory;
+};
+
+/**
+ * Stores an embed visit, and notifies observers.
+ *
+ * @param aPlace
+ *        The VisitData of the visit to store as an embed visit.
+ * @param [optional] aCallback
+ *        The mozIVisitInfoCallback to notify, if provided.
+ *
+ * FIXME(emilio, bug 1595484): We should get rid of EMBED visits completely.
+ */
+void NotifyEmbedVisit(VisitData& aPlace,
+                      mozIVisitInfoCallback* aCallback = nullptr) {
+  MOZ_ASSERT(aPlace.transitionType == nsINavHistoryService::TRANSITION_EMBED,
+             "Must only pass TRANSITION_EMBED visits to this!");
+  MOZ_ASSERT(NS_IsMainThread(), "Must be called on the main thread!");
+
+  nsCOMPtr<nsIURI> uri;
+  if (NS_WARN_IF(NS_FAILED(NS_NewURI(getter_AddRefs(uri), aPlace.spec)))) {
+    return;
+  }
+
+  if (!!aCallback) {
+    nsMainThreadPtrHandle<mozIVisitInfoCallback> callback(
+        new nsMainThreadPtrHolder<mozIVisitInfoCallback>(
+            "mozIVisitInfoCallback", aCallback));
+    bool ignoreResults = false;
+    Unused << aCallback->GetIgnoreResults(&ignoreResults);
+    if (!ignoreResults) {
+      nsCOMPtr<nsIRunnable> event =
+          new NotifyPlaceInfoCallback(callback, aPlace, true, NS_OK);
+      (void)NS_DispatchToMainThread(event);
+    }
+  }
+
+  nsCOMPtr<nsIRunnable> event = new NotifyManyVisitsObservers(aPlace);
+  (void)NS_DispatchToMainThread(event);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// History
+
+History* History::gService = nullptr;
+
+History::History()
+    : mShuttingDown(false),
+      mShuttingDownMutex("History::mShuttingDownMutex"),
+      mBlockShutdownMutex("History::mBlockShutdownMutex"),
+      mRecentlyVisitedURIs(RECENTLY_VISITED_URIS_SIZE) {
+  NS_ASSERTION(!gService, "Ruh-roh!  This service has already been created!");
+  if (XRE_IsParentProcess()) {
+    nsCOMPtr<nsIProperties> dirsvc = components::Directory::Service();
+    bool haveProfile = false;
+    MOZ_RELEASE_ASSERT(
+        dirsvc &&
+            NS_SUCCEEDED(
+                dirsvc->Has(NS_APP_USER_PROFILE_50_DIR, &haveProfile)) &&
+            haveProfile,
+        "Can't construct history service if there is no profile.");
+  }
+  gService = this;
+
+  nsCOMPtr<nsIObserverService> os = services::GetObserverService();
+  NS_WARNING_ASSERTION(os, "Observer service was not found!");
+  if (os) {
+    (void)os->AddObserver(this, TOPIC_PLACES_SHUTDOWN, false);
+  }
+}
+
+History::~History() {
+  UnregisterWeakMemoryReporter(this);
+
+  MOZ_ASSERT(gService == this);
+  gService = nullptr;
+}
+
+void History::InitMemoryReporter() { RegisterWeakMemoryReporter(this); }
+
+class ConcurrentStatementsHolder final : public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS
+
+  ConcurrentStatementsHolder() : mShutdownWasInvoked(false) {}
+
+  static RefPtr<ConcurrentStatementsHolder> Create(
+      mozIStorageConnection* aDBConn) {
+    RefPtr<ConcurrentStatementsHolder> holder =
+        new ConcurrentStatementsHolder();
+    nsresult rv = aDBConn->AsyncClone(true, holder);
+    if (NS_FAILED(rv)) {
+      return nullptr;
+    }
+    return holder;
+  }
+
+  NS_IMETHOD Complete(nsresult aStatus, nsISupports* aConnection) override {
+    if (NS_FAILED(aStatus)) {
+      return NS_OK;
+    }
+    mReadOnlyDBConn = do_QueryInterface(aConnection);
+    // It's possible Shutdown was invoked before we were handed back the
+    // cloned connection handle.
+    if (mShutdownWasInvoked) {
+      Shutdown();
+      return NS_OK;
+    }
+
+    // Now we can create our cached statements.
+
+    if (!mIsVisitedStatement) {
+      (void)mReadOnlyDBConn->CreateAsyncStatement(
+          nsLiteralCString("SELECT 1 FROM moz_places h "
+                           "WHERE url_hash = hash(?1) AND url = ?1 AND "
+                           "last_visit_date NOTNULL "),
+          getter_AddRefs(mIsVisitedStatement));
+      MOZ_ASSERT(mIsVisitedStatement);
+      auto queries = std::move(mVisitedQueries);
+      if (mIsVisitedStatement) {
+        for (auto& query : queries) {
+          query->Execute(*mIsVisitedStatement);
+        }
+      }
+    }
+
+    return NS_OK;
+  }
+
+  void QueueVisitedStatement(RefPtr<VisitedQuery> aCallback) {
+    if (mIsVisitedStatement) {
+      aCallback->Execute(*mIsVisitedStatement);
+    } else {
+      mVisitedQueries.AppendElement(std::move(aCallback));
+    }
+  }
+
+  void Shutdown() {
+    mShutdownWasInvoked = true;
+    if (mReadOnlyDBConn) {
+      mVisitedQueries.Clear();
+      DebugOnly<nsresult> rv;
+      if (mIsVisitedStatement) {
+        rv = mIsVisitedStatement->Finalize();
+        MOZ_ASSERT(NS_SUCCEEDED(rv));
+      }
+      rv = mReadOnlyDBConn->AsyncClose(nullptr);
+      MOZ_ASSERT(NS_SUCCEEDED(rv));
+      mReadOnlyDBConn = nullptr;
+    }
+  }
+
+ private:
+  ~ConcurrentStatementsHolder() = default;
+
+  nsCOMPtr<mozIStorageAsyncConnection> mReadOnlyDBConn;
+  nsCOMPtr<mozIStorageAsyncStatement> mIsVisitedStatement;
+  nsTArray<RefPtr<VisitedQuery>> mVisitedQueries;
+  bool mShutdownWasInvoked;
+};
+
+NS_IMPL_ISUPPORTS(ConcurrentStatementsHolder, mozIStorageCompletionCallback)
+
+nsresult History::QueueVisitedStatement(RefPtr<VisitedQuery> aQuery) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (IsShuttingDown()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (!mConcurrentStatementsHolder) {
+    mozIStorageConnection* dbConn = GetDBConn();
+    NS_ENSURE_STATE(dbConn);
+    mConcurrentStatementsHolder = ConcurrentStatementsHolder::Create(dbConn);
+    if (!mConcurrentStatementsHolder) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+  }
+  mConcurrentStatementsHolder->QueueVisitedStatement(std::move(aQuery));
+  return NS_OK;
+}
+
+nsresult History::InsertPlace(VisitData& aPlace) {
+  MOZ_ASSERT(aPlace.placeId == 0, "should not have a valid place id!");
+  MOZ_ASSERT(!NS_IsMainThread(), "must be called off of the main thread!");
+
+  nsCOMPtr<mozIStorageStatement> stmt = GetStatement(
+      "INSERT INTO moz_places "
+      "(url, url_hash, title, rev_host, hidden, typed, frecency, guid) "
+      "VALUES (:url, hash(:url), :title, :rev_host, :hidden, :typed, "
+      ":frecency, :guid) ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindStringByName("rev_host"_ns, aPlace.revHost);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = URIBinder::Bind(stmt, "url"_ns, aPlace.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsString title = aPlace.title;
+  // Empty strings should have no title, just like nsNavHistory::SetPageTitle.
+  if (title.IsEmpty()) {
+    rv = stmt->BindNullByName("title"_ns);
+  } else {
+    title.Assign(StringHead(aPlace.title, TITLE_LENGTH_MAX));
+    rv = stmt->BindStringByName("title"_ns, title);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("typed"_ns, aPlace.typed);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // When inserting a page for a first visit that should not appear in
+  // autocomplete, for example an error page, use a zero frecency.
+  int32_t frecency = aPlace.isUnrecoverableError ? 0 : aPlace.frecency;
+  rv = stmt->BindInt32ByName("frecency"_ns, frecency);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("hidden"_ns, aPlace.hidden);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (aPlace.guid.IsVoid()) {
+    rv = GenerateGUID(aPlace.guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  rv = stmt->BindUTF8StringByName("guid"_ns, aPlace.guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult History::UpdatePlace(const VisitData& aPlace) {
+  MOZ_ASSERT(!NS_IsMainThread(), "must be called off of the main thread!");
+  MOZ_ASSERT(aPlace.placeId > 0, "must have a valid place id!");
+  MOZ_ASSERT(!aPlace.guid.IsVoid(), "must have a guid!");
+
+  nsCOMPtr<mozIStorageStatement> stmt;
+  bool titleIsVoid = aPlace.title.IsVoid();
+  if (titleIsVoid) {
+    // Don't change the title.
+    stmt = GetStatement(
+        "UPDATE moz_places "
+        "SET hidden = :hidden, "
+        "typed = :typed, "
+        "guid = :guid "
+        "WHERE id = :page_id ");
+  } else {
+    stmt = GetStatement(
+        "UPDATE moz_places "
+        "SET title = :title, "
+        "hidden = :hidden, "
+        "typed = :typed, "
+        "guid = :guid "
+        "WHERE id = :page_id ");
+  }
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv;
+  if (!titleIsVoid) {
+    // An empty string clears the title.
+    if (aPlace.title.IsEmpty()) {
+      rv = stmt->BindNullByName("title"_ns);
+    } else {
+      rv = stmt->BindStringByName("title"_ns,
+                                  StringHead(aPlace.title, TITLE_LENGTH_MAX));
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  rv = stmt->BindInt32ByName("typed"_ns, aPlace.typed);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("hidden"_ns, aPlace.hidden);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindUTF8StringByName("guid"_ns, aPlace.guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("page_id"_ns, aPlace.placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult History::FetchPageInfo(VisitData& _place, bool* _exists) {
+  MOZ_ASSERT(!_place.spec.IsEmpty() || !_place.guid.IsEmpty(),
+             "must have either a non-empty spec or guid!");
+  MOZ_ASSERT(!NS_IsMainThread(), "must be called off of the main thread!");
+
+  nsresult rv;
+
+  // URI takes precedence.
+  nsCOMPtr<mozIStorageStatement> stmt;
+  bool selectByURI = !_place.spec.IsEmpty();
+  if (selectByURI) {
+    stmt = GetStatement(
+        "SELECT guid, id, title, hidden, typed, frecency, visit_count, "
+        "last_visit_date, "
+        "(SELECT id FROM moz_historyvisits "
+        "WHERE place_id = h.id AND visit_date = h.last_visit_date) AS "
+        "last_visit_id, "
+        "EXISTS(SELECT 1 FROM moz_bookmarks WHERE fk = h.id) AS bookmarked "
+        "FROM moz_places h "
+        "WHERE url_hash = hash(:page_url) AND url = :page_url ");
+    NS_ENSURE_STATE(stmt);
+
+    rv = URIBinder::Bind(stmt, "page_url"_ns, _place.spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    stmt = GetStatement(
+        "SELECT url, id, title, hidden, typed, frecency, visit_count, "
+        "last_visit_date, "
+        "(SELECT id FROM moz_historyvisits "
+        "WHERE place_id = h.id AND visit_date = h.last_visit_date) AS "
+        "last_visit_id, "
+        "EXISTS(SELECT 1 FROM moz_bookmarks WHERE fk = h.id) AS bookmarked "
+        "FROM moz_places h "
+        "WHERE guid = :guid ");
+    NS_ENSURE_STATE(stmt);
+
+    rv = stmt->BindUTF8StringByName("guid"_ns, _place.guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  mozStorageStatementScoper scoper(stmt);
+
+  rv = stmt->ExecuteStep(_exists);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!*_exists) {
+    return NS_OK;
+  }
+
+  if (selectByURI) {
+    if (_place.guid.IsEmpty()) {
+      rv = stmt->GetUTF8String(0, _place.guid);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  } else {
+    nsAutoCString spec;
+    rv = stmt->GetUTF8String(0, spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    _place.spec = spec;
+  }
+
+  rv = stmt->GetInt64(1, &_place.placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoString title;
+  rv = stmt->GetString(2, title);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If the title we were given was void, that means we did not bother to set
+  // it to anything.  As a result, ignore the fact that we may have changed the
+  // title (because we don't want to, that would be empty), and set the title
+  // to what is currently stored in the datbase.
+  if (_place.title.IsVoid()) {
+    _place.title = title;
+  }
+  // Otherwise, just indicate if the title has changed.
+  else {
+    _place.titleChanged = !(_place.title.Equals(title)) &&
+                          !(_place.title.IsEmpty() && title.IsVoid());
+  }
+
+  int32_t hidden;
+  rv = stmt->GetInt32(3, &hidden);
+  NS_ENSURE_SUCCESS(rv, rv);
+  _place.hidden = !!hidden;
+
+  int32_t typed;
+  rv = stmt->GetInt32(4, &typed);
+  NS_ENSURE_SUCCESS(rv, rv);
+  _place.typed = !!typed;
+
+  rv = stmt->GetInt32(5, &_place.frecency);
+  NS_ENSURE_SUCCESS(rv, rv);
+  int32_t visitCount;
+  rv = stmt->GetInt32(6, &visitCount);
+  NS_ENSURE_SUCCESS(rv, rv);
+  _place.visitCount = visitCount;
+  rv = stmt->GetInt64(7, &_place.lastVisitTime);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(8, &_place.lastVisitId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  int32_t bookmarked;
+  rv = stmt->GetInt32(9, &bookmarked);
+  NS_ENSURE_SUCCESS(rv, rv);
+  _place.bookmarked = bookmarked == 1;
+
+  return NS_OK;
+}
+
+MOZ_DEFINE_MALLOC_SIZE_OF(HistoryMallocSizeOf)
+
+NS_IMETHODIMP
+History::CollectReports(nsIHandleReportCallback* aHandleReport,
+                        nsISupports* aData, bool aAnonymize) {
+  MOZ_COLLECT_REPORT(
+      "explicit/history-links-hashtable", KIND_HEAP, UNITS_BYTES,
+      SizeOfIncludingThis(HistoryMallocSizeOf),
+      "Memory used by the hashtable that records changes to the visited state "
+      "of links.");
+
+  return NS_OK;
+}
+
+size_t History::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+  size_t size = aMallocSizeOf(this);
+  size += mTrackedURIs.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  for (const auto& entry : mTrackedURIs.Values()) {
+    size += entry.SizeOfExcludingThis(aMallocSizeOf);
+  }
+  return size;
+}
+
+/* static */
+History* History::GetService() {
+  if (gService) {
+    return gService;
+  }
+
+  nsCOMPtr<IHistory> service = components::History::Service();
+  if (service) {
+    NS_ASSERTION(gService, "Our constructor was not run?!");
+  }
+
+  return gService;
+}
+
+/* static */
+already_AddRefed<History> History::GetSingleton() {
+  if (!gService) {
+    RefPtr<History> svc = new History();
+    MOZ_ASSERT(gService == svc.get());
+    svc->InitMemoryReporter();
+    return svc.forget();
+  }
+
+  return do_AddRef(gService);
+}
+
+mozIStorageConnection* History::GetDBConn() {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (IsShuttingDown()) {
+    return nullptr;
+  }
+  if (!mDB) {
+    mDB = Database::GetDatabase();
+    NS_ENSURE_TRUE(mDB, nullptr);
+    // This must happen on the main-thread, so when we try to use the connection
+    // later it's initialized.
+    mDB->EnsureConnection();
+    NS_ENSURE_TRUE(mDB, nullptr);
+  }
+  return mDB->MainConn();
+}
+
+const mozIStorageConnection* History::GetConstDBConn() {
+  MOZ_ASSERT(!NS_IsMainThread());
+  {
+    MOZ_ASSERT(mDB || IsShuttingDown());
+    if (IsShuttingDown() || !mDB) {
+      return nullptr;
+    }
+  }
+  return mDB->MainConn();
+}
+
+void History::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MutexAutoLock lockedScope(mBlockShutdownMutex);
+  {
+    MutexAutoLock lockedScope(mShuttingDownMutex);
+    MOZ_ASSERT(!mShuttingDown && "Shutdown was called more than once!");
+    mShuttingDown = true;
+  }
+  if (mConcurrentStatementsHolder) {
+    mConcurrentStatementsHolder->Shutdown();
+  }
+}
+
+void History::AppendToRecentlyVisitedURIs(nsIURI* aURI, bool aHidden) {
+  PRTime now = PR_Now();
+
+  mRecentlyVisitedURIs.InsertOrUpdate(aURI, RecentURIVisit{now, aHidden});
+
+  // Remove entries older than RECENTLY_VISITED_URIS_MAX_AGE.
+  for (auto iter = mRecentlyVisitedURIs.Iter(); !iter.Done(); iter.Next()) {
+    if ((now - iter.Data().mTime) > RECENTLY_VISITED_URIS_MAX_AGE) {
+      iter.Remove();
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// IHistory
+
+NS_IMETHODIMP
+History::VisitURI(nsIWidget* aWidget, nsIURI* aURI, nsIURI* aLastVisitedURI,
+                  uint32_t aFlags, uint64_t aBrowserId) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aURI);
+
+  if (IsShuttingDown()) {
+    return NS_OK;
+  }
+
+  if (XRE_IsContentProcess()) {
+    if (!BaseHistory::CanStore(aURI)) {
+      return NS_OK;
+    }
+
+    NS_ENSURE_ARG(aWidget);
+    BrowserChild* browserChild = aWidget->GetOwningBrowserChild();
+    NS_ENSURE_TRUE(browserChild, NS_ERROR_FAILURE);
+    (void)browserChild->SendVisitURI(aURI, aLastVisitedURI, aFlags, aBrowserId);
+    return NS_OK;
+  }
+
+  nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(navHistory, NS_ERROR_OUT_OF_MEMORY);
+
+  // Silently return if URI is something we shouldn't add to DB.
+  bool canAdd;
+  nsresult rv = navHistory->CanAddURI(aURI, &canAdd);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!canAdd) {
+    return NS_OK;
+  }
+
+  bool reload = false;
+  if (aLastVisitedURI) {
+    rv = aURI->Equals(aLastVisitedURI, &reload);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsTArray<VisitData> placeArray(1);
+  placeArray.AppendElement(VisitData(aURI, aLastVisitedURI));
+  VisitData& place = placeArray.ElementAt(0);
+  NS_ENSURE_FALSE(place.spec.IsEmpty(), NS_ERROR_INVALID_ARG);
+
+  place.visitTime = PR_Now();
+
+  // Assigns a type to the edge in the visit linked list. Each type will be
+  // considered differently when weighting the frecency of a location.
+  uint32_t recentFlags = navHistory->GetRecentFlags(aURI);
+  bool isFollowedLink = recentFlags & nsNavHistory::RECENT_ACTIVATED;
+
+  // Embed visits should never be added to the database, and the same is valid
+  // for redirects across frames.
+  // For the above reasoning non-toplevel transitions are handled at first.
+  // if the visit is toplevel or a non-toplevel followed link, then it can be
+  // handled as usual and stored on disk.
+
+  uint32_t transitionType = nsINavHistoryService::TRANSITION_LINK;
+
+  if (!(aFlags & IHistory::TOP_LEVEL) && !isFollowedLink) {
+    // A frame redirected to a new site without user interaction.
+    transitionType = nsINavHistoryService::TRANSITION_EMBED;
+  } else if (aFlags & IHistory::REDIRECT_TEMPORARY) {
+    transitionType = nsINavHistoryService::TRANSITION_REDIRECT_TEMPORARY;
+  } else if (aFlags & IHistory::REDIRECT_PERMANENT) {
+    transitionType = nsINavHistoryService::TRANSITION_REDIRECT_PERMANENT;
+  } else if (reload) {
+    transitionType = nsINavHistoryService::TRANSITION_RELOAD;
+  } else if ((recentFlags & nsNavHistory::RECENT_TYPED) &&
+             !(aFlags & IHistory::UNRECOVERABLE_ERROR)) {
+    // Don't mark error pages as typed, even if they were actually typed by
+    // the user.  This is useful to limit their score in autocomplete.
+    transitionType = nsINavHistoryService::TRANSITION_TYPED;
+  } else if (recentFlags & nsNavHistory::RECENT_BOOKMARKED) {
+    transitionType = nsINavHistoryService::TRANSITION_BOOKMARK;
+  } else if (!(aFlags & IHistory::TOP_LEVEL) && isFollowedLink) {
+    // User activated a link in a frame.
+    transitionType = nsINavHistoryService::TRANSITION_FRAMED_LINK;
+  }
+
+  place.SetTransitionType(transitionType);
+  bool isRedirect = aFlags & IHistory::REDIRECT_SOURCE;
+  if (isRedirect) {
+    place.useFrecencyRedirectBonus =
+        (aFlags & (IHistory::REDIRECT_SOURCE_PERMANENT |
+                   IHistory::REDIRECT_SOURCE_UPGRADED)) ||
+        transitionType != nsINavHistoryService::TRANSITION_TYPED;
+  }
+  place.hidden = GetHiddenState(isRedirect, place.transitionType);
+
+  // Error pages should never be autocompleted.
+  place.isUnrecoverableError = aFlags & IHistory::UNRECOVERABLE_ERROR;
+
+  // Do not save a reloaded uri if we have visited the same URI recently.
+  if (reload) {
+    auto entry = mRecentlyVisitedURIs.Lookup(aURI);
+    // Check if the entry exists and is younger than
+    // RECENTLY_VISITED_URIS_MAX_AGE.
+    if (entry && (PR_Now() - entry->mTime) < RECENTLY_VISITED_URIS_MAX_AGE) {
+      bool wasHidden = entry->mHidden;
+      // Regardless of whether we store the visit or not, we must update the
+      // stored visit time.
+      AppendToRecentlyVisitedURIs(aURI, place.hidden);
+      // We always want to store an unhidden visit, if the previous visits were
+      // hidden, because otherwise the page may not appear in the history UI.
+      // This can happen for example at a page redirecting to itself.
+      if (!wasHidden || place.hidden) {
+        // We can skip this visit.
+        return NS_OK;
+      }
+    }
+  }
+
+  nsCOMPtr<nsIBrowserWindowTracker> bwt =
+      do_ImportESModule("resource:///modules/BrowserWindowTracker.sys.mjs",
+                        "BrowserWindowTracker", &rv);
+  if (NS_SUCCEEDED(rv)) {
+    // Only if it is running on Firefox, continue to process the followings.
+    nsCOMPtr<nsISupports> browser;
+    rv = bwt->GetBrowserById(aBrowserId, getter_AddRefs(browser));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (browser) {
+      RefPtr<Element> browserElement = static_cast<Element*>(browser.get());
+
+      nsAutoString triggeringSearchEngineURL;
+      browserElement->GetAttribute(u"triggeringSearchEngineURL"_ns,
+                                   triggeringSearchEngineURL);
+      if (!triggeringSearchEngineURL.IsEmpty() &&
+          place.spec.Equals(NS_ConvertUTF16toUTF8(triggeringSearchEngineURL))) {
+        nsAutoString triggeringSearchEngine;
+        browserElement->GetAttribute(u"triggeringSearchEngine"_ns,
+                                     triggeringSearchEngine);
+        place.triggeringSearchEngine.Assign(
+            NS_ConvertUTF16toUTF8(triggeringSearchEngine));
+      }
+
+      nsAutoString triggeringSponsoredURL;
+      browserElement->GetAttribute(u"triggeringSponsoredURL"_ns,
+                                   triggeringSponsoredURL);
+      if (!triggeringSponsoredURL.IsEmpty()) {
+        place.triggeringSponsoredURL.Assign(
+            NS_ConvertUTF16toUTF8(triggeringSponsoredURL));
+
+        nsAutoString triggeringSponsoredURLVisitTimeMS;
+        browserElement->GetAttribute(u"triggeringSponsoredURLVisitTimeMS"_ns,
+                                     triggeringSponsoredURLVisitTimeMS);
+        place.triggeringSponsoredURLVisitTimeMS =
+            triggeringSponsoredURLVisitTimeMS.ToInteger64(&rv);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        // Get base domain. We need to get it here since nsIEffectiveTLDService
+        // referred in DomainNameFromURI should access on main thread.
+        nsCOMPtr<nsIURI> currentURL;
+        rv = NS_MutateURI(new net::nsStandardURL::Mutator())
+                 .SetSpec(place.spec)
+                 .Finalize(currentURL);
+        NS_ENSURE_SUCCESS(rv, rv);
+        nsCOMPtr<nsIURI> sponsoredURL;
+        rv = NS_MutateURI(new net::nsStandardURL::Mutator())
+                 .SetSpec(place.triggeringSponsoredURL)
+                 .Finalize(sponsoredURL);
+        NS_ENSURE_SUCCESS(rv, rv);
+        navHistory->DomainNameFromURI(currentURL, place.baseDomain);
+        navHistory->DomainNameFromURI(sponsoredURL,
+                                      place.triggeringSponsoredURLBaseDomain);
+      }
+    }
+  }
+
+  // EMBED visits should not go through the database.
+  // They exist only to keep track of isVisited status during the session.
+  if (place.transitionType == nsINavHistoryService::TRANSITION_EMBED) {
+    NotifyEmbedVisit(place);
+  } else {
+    mozIStorageConnection* dbConn = GetDBConn();
+    NS_ENSURE_STATE(dbConn);
+
+    rv = InsertVisitedURIs::Start(dbConn, std::move(placeArray));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+History::SetURITitle(nsIURI* aURI, const nsAString& aTitle) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aURI);
+
+  if (IsShuttingDown()) {
+    return NS_OK;
+  }
+
+  if (XRE_IsContentProcess()) {
+    auto* cpc = dom::ContentChild::GetSingleton();
+    MOZ_ASSERT(cpc, "Content Protocol is NULL!");
+    Unused << cpc->SendSetURITitle(aURI, PromiseFlatString(aTitle));
+    return NS_OK;
+  }
+
+  nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+
+  // At first, it seems like nav history should always be available here, no
+  // matter what.
+  //
+  // nsNavHistory fails to register as a service if there is no profile in
+  // place (for instance, if user is choosing a profile).
+  //
+  // Maybe the correct thing to do is to not register this service if no
+  // profile has been selected?
+  //
+  NS_ENSURE_TRUE(navHistory, NS_ERROR_FAILURE);
+
+  bool canAdd;
+  nsresult rv = navHistory->CanAddURI(aURI, &canAdd);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!canAdd) {
+    return NS_OK;
+  }
+
+  mozIStorageConnection* dbConn = GetDBConn();
+  NS_ENSURE_STATE(dbConn);
+
+  return SetPageTitle::Start(dbConn, aURI, aTitle);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIAsyncHistory
+
+NS_IMETHODIMP
+History::UpdatePlaces(JS::Handle<JS::Value> aPlaceInfos,
+                      mozIVisitInfoCallback* aCallback, JSContext* aCtx) {
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_UNEXPECTED);
+  NS_ENSURE_TRUE(!aPlaceInfos.isPrimitive(), NS_ERROR_INVALID_ARG);
+
+  uint32_t infosLength;
+  JS::Rooted<JSObject*> infos(aCtx);
+  nsresult rv = GetJSArrayFromJSValue(aPlaceInfos, aCtx, &infos, &infosLength);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint32_t initialUpdatedCount = 0;
+
+  nsTArray<VisitData> visitData;
+  for (uint32_t i = 0; i < infosLength; i++) {
+    JS::Rooted<JSObject*> info(aCtx);
+    nsresult rv = GetJSObjectFromArray(aCtx, infos, i, &info);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsCOMPtr<nsIURI> uri = GetURIFromJSObject(aCtx, info, "uri");
+    nsCString guid;
+    {
+      nsString fatGUID;
+      GetStringFromJSObject(aCtx, info, "guid", fatGUID);
+      if (fatGUID.IsVoid()) {
+        guid.SetIsVoid(true);
+      } else {
+        CopyUTF16toUTF8(fatGUID, guid);
+      }
+    }
+
+    // Make sure that any uri we are given can be added to history, and if not,
+    // skip it (CanAddURI will notify our callback for us).
+    if (uri && !CanAddURI(uri, guid, aCallback)) {
+      continue;
+    }
+
+    // We must have at least one of uri or guid.
+    NS_ENSURE_ARG(uri || !guid.IsVoid());
+
+    // If we were given a guid, make sure it is valid.
+    bool isValidGUID = IsValidGUID(guid);
+    NS_ENSURE_ARG(guid.IsVoid() || isValidGUID);
+
+    nsString title;
+    GetStringFromJSObject(aCtx, info, "title", title);
+
+    JS::Rooted<JSObject*> visits(aCtx, nullptr);
+    {
+      JS::Rooted<JS::Value> visitsVal(aCtx);
+      bool rc = JS_GetProperty(aCtx, info, "visits", &visitsVal);
+      NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+      if (!visitsVal.isPrimitive()) {
+        visits = visitsVal.toObjectOrNull();
+        bool isArray;
+        if (!JS::IsArrayObject(aCtx, visits, &isArray)) {
+          return NS_ERROR_UNEXPECTED;
+        }
+        if (!isArray) {
+          return NS_ERROR_INVALID_ARG;
+        }
+      }
+    }
+    NS_ENSURE_ARG(visits);
+
+    uint32_t visitsLength = 0;
+    if (visits) {
+      (void)JS::GetArrayLength(aCtx, visits, &visitsLength);
+    }
+    NS_ENSURE_ARG(visitsLength > 0);
+
+    // Check each visit, and build our array of VisitData objects.
+    visitData.SetCapacity(visitData.Length() + visitsLength);
+    for (uint32_t j = 0; j < visitsLength; j++) {
+      JS::Rooted<JSObject*> visit(aCtx);
+      rv = GetJSObjectFromArray(aCtx, visits, j, &visit);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      VisitData& data = *visitData.AppendElement(VisitData(uri));
+      if (!title.IsEmpty()) {
+        data.title = title;
+      } else if (!title.IsVoid()) {
+        // Setting data.title to an empty string wouldn't make it non-void.
+        data.title.SetIsVoid(false);
+      }
+      data.guid = guid;
+
+      // We must have a date and a transaction type!
+      rv = GetIntFromJSObject(aCtx, visit, "visitDate", &data.visitTime);
+      NS_ENSURE_SUCCESS(rv, rv);
+      // visitDate should be in microseconds. It's easy to do the wrong thing
+      // and pass milliseconds to updatePlaces, so we lazily check for that.
+      // While it's not easily distinguishable, since both are integers, we can
+      // check if the value is very far in the past, and assume it's probably
+      // a mistake.
+      if (data.visitTime < (PR_Now() / 1000)) {
+#ifdef DEBUG
+        nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+        Unused << xpc->DebugDumpJSStack(false, false, false);
+        MOZ_CRASH("invalid time format passed to updatePlaces");
+#endif
+        return NS_ERROR_INVALID_ARG;
+      }
+      uint32_t transitionType = 0;
+      rv = GetIntFromJSObject(aCtx, visit, "transitionType", &transitionType);
+      NS_ENSURE_SUCCESS(rv, rv);
+      NS_ENSURE_ARG_RANGE(transitionType, nsINavHistoryService::TRANSITION_LINK,
+                          nsINavHistoryService::TRANSITION_RELOAD);
+      data.SetTransitionType(transitionType);
+      data.hidden = GetHiddenState(false, transitionType);
+
+      // If the visit is an embed visit, we do not actually add it to the
+      // database.
+      if (transitionType == nsINavHistoryService::TRANSITION_EMBED) {
+        NotifyEmbedVisit(data, aCallback);
+        visitData.RemoveLastElement();
+        initialUpdatedCount++;
+        continue;
+      }
+
+      // The referrer is optional.
+      nsCOMPtr<nsIURI> referrer =
+          GetURIFromJSObject(aCtx, visit, "referrerURI");
+      if (referrer) {
+        (void)referrer->GetSpec(data.referrerSpec);
+      }
+    }
+  }
+
+  mozIStorageConnection* dbConn = GetDBConn();
+  NS_ENSURE_STATE(dbConn);
+
+  nsMainThreadPtrHandle<mozIVisitInfoCallback> callback(
+      new nsMainThreadPtrHolder<mozIVisitInfoCallback>("mozIVisitInfoCallback",
+                                                       aCallback));
+
+  // It is possible that all of the visits we were passed were dissallowed by
+  // CanAddURI, which isn't an error.  If we have no visits to add, however,
+  // we should not call InsertVisitedURIs::Start.
+  if (visitData.Length()) {
+    nsresult rv = InsertVisitedURIs::Start(dbConn, std::move(visitData),
+                                           callback, initialUpdatedCount);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else if (aCallback) {
+    // Be sure to notify that all of our operations are complete.  This
+    // is dispatched to the background thread first and redirected to the
+    // main thread from there to make sure that all database notifications
+    // and all embed or canAddURI notifications have finished.
+
+    // Note: if we're inserting anything, it's the responsibility of
+    // InsertVisitedURIs to call the completion callback, as here we won't
+    // know how yet many items we will successfully insert/update.
+    nsCOMPtr<nsIEventTarget> backgroundThread = do_GetInterface(dbConn);
+    NS_ENSURE_TRUE(backgroundThread, NS_ERROR_UNEXPECTED);
+    nsCOMPtr<nsIRunnable> event =
+        new NotifyCompletion(callback, initialUpdatedCount);
+    return backgroundThread->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+History::IsURIVisited(nsIURI* aURI, mozIVisitedStatusCallback* aCallback) {
+  NS_ENSURE_STATE(NS_IsMainThread());
+  NS_ENSURE_ARG(aURI);
+  NS_ENSURE_ARG(aCallback);
+
+  return VisitedQuery::Start(aURI, aCallback);
+}
+
+NS_IMETHODIMP
+History::ClearCache() {
+  mRecentlyVisitedURIs.Clear();
+  return NS_OK;
+}
+
+void History::StartPendingVisitedQueries(PendingVisitedQueries&& aQueries) {
+  if (XRE_IsContentProcess()) {
+    auto* cpc = dom::ContentChild::GetSingleton();
+    MOZ_ASSERT(cpc, "Content Protocol is NULL!");
+
+    // Fairly arbitrary limit on the number of URLs we send at a time, to avoid
+    // going over the IPC message size limit... Note that this is imperfect (we
+    // could have very long URIs), so this is a best-effort kind of thing. See
+    // bug 1775265.
+    constexpr size_t kBatchLimit = 4000;
+
+    nsTArray<RefPtr<nsIURI>> uris(aQueries.Count());
+    for (const auto& entry : aQueries) {
+      uris.AppendElement(entry.GetKey());
+      MOZ_ASSERT(entry.GetData().IsEmpty(),
+                 "Child process shouldn't have parent requests");
+      if (uris.Length() == kBatchLimit) {
+        Unused << cpc->SendStartVisitedQueries(uris);
+        uris.ClearAndRetainStorage();
+      }
+    }
+
+    if (!uris.IsEmpty()) {
+      Unused << cpc->SendStartVisitedQueries(uris);
+    }
+  } else {
+    // TODO(bug 1594368): We could do a single query, as long as we can
+    // then notify each URI individually.
+    for (auto& entry : aQueries) {
+      nsresult queryStatus = VisitedQuery::Start(
+          entry.GetKey(), std::move(*entry.GetModifiableData()));
+      Unused << NS_WARN_IF(NS_FAILED(queryStatus));
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+History::Observe(nsISupports* aSubject, const char* aTopic,
+                 const char16_t* aData) {
+  if (strcmp(aTopic, TOPIC_PLACES_SHUTDOWN) == 0) {
+    Shutdown();
+
+    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+    if (os) {
+      (void)os->RemoveObserver(this, TOPIC_PLACES_SHUTDOWN);
+    }
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ISUPPORTS(History, IHistory, mozIAsyncHistory, nsIObserver,
+                  nsIMemoryReporter)
+
+}  // namespace mozilla::places
diff --git a/toolkit/components/places/History.h b/toolkit/components/places/History.h
new file mode 100644
index 0000000000..03a31186fd
--- /dev/null
+++ b/toolkit/components/places/History.h
@@ -0,0 +1,203 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_History_h_
+#define mozilla_places_History_h_
+
+#include <utility>
+
+#include "Database.h"
+#include "mozIAsyncHistory.h"
+#include "mozIStorageConnection.h"
+#include "mozilla/BaseHistory.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/dom/Link.h"
+#include "mozilla/dom/PContentChild.h"
+#include "nsTHashMap.h"
+#include "nsIMemoryReporter.h"
+#include "nsIObserver.h"
+#include "nsString.h"
+#include "nsTHashtable.h"
+#include "nsTObserverArray.h"
+#include "nsURIHashKey.h"
+
+namespace mozilla::places {
+
+struct VisitData;
+class ConcurrentStatementsHolder;
+class VisitedQuery;
+
+// Initial size of mRecentlyVisitedURIs.
+#define RECENTLY_VISITED_URIS_SIZE 64
+// Microseconds after which a visit can be expired from mRecentlyVisitedURIs.
+// When an URI is reloaded we only take into account the first visit to it, and
+// ignore any subsequent visits, if they happen before this time has elapsed.
+// A commonly found case is to reload a page every 5 minutes, so we pick a time
+// larger than that.
+#define RECENTLY_VISITED_URIS_MAX_AGE (6 * 60 * PR_USEC_PER_SEC)
+// When notifying the main thread after inserting visits, we chunk the visits
+// into medium-sized groups so that we can amortize the cost of the runnable
+// without janking the main thread by expecting it to process hundreds at once.
+#define NOTIFY_VISITS_CHUNK_SIZE 100
+
+class History final : public BaseHistory,
+                      public mozIAsyncHistory,
+                      public nsIObserver,
+                      public nsIMemoryReporter {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZIASYNCHISTORY
+  NS_DECL_NSIOBSERVER
+  NS_DECL_NSIMEMORYREPORTER
+
+  // IHistory
+  NS_IMETHOD VisitURI(nsIWidget*, nsIURI*, nsIURI* aLastVisitedURI,
+                      uint32_t aFlags, uint64_t aBrowserId) final;
+  NS_IMETHOD SetURITitle(nsIURI*, const nsAString&) final;
+
+  // BaseHistory
+  void StartPendingVisitedQueries(PendingVisitedQueries&&) final;
+
+  History();
+
+  nsresult QueueVisitedStatement(RefPtr<VisitedQuery>);
+
+  /**
+   * Adds an entry in moz_places with the data in aVisitData.
+   *
+   * @param aPlace
+   *        The visit data to use to populate a new row in moz_places.
+   */
+  nsresult InsertPlace(VisitData& aPlace);
+
+  /**
+   * Updates an entry in moz_places with the data in aVisitData.
+   *
+   * @param aPlace
+   *        The visit data to use to update the existing row in moz_places.
+   */
+  nsresult UpdatePlace(const VisitData& aPlace);
+
+  /**
+   * Loads information about the page into _place from moz_places.
+   *
+   * @param _place
+   *        The VisitData for the place we need to know information about.
+   * @param [out] _exists
+   *        Whether or the page was recorded in moz_places, false otherwise.
+   */
+  nsresult FetchPageInfo(VisitData& _place, bool* _exists);
+
+  /**
+   * Get the number of bytes of memory this History object is using,
+   * including sizeof(*this))
+   */
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
+
+  /**
+   * Obtains a pointer to this service.
+   */
+  static History* GetService();
+
+  /**
+   * Used by the service manager only.
+   */
+  static already_AddRefed<History> GetSingleton();
+
+  template <int N>
+  already_AddRefed<mozIStorageStatement> GetStatement(const char (&aQuery)[N]) {
+    // May be invoked on both threads.
+    const mozIStorageConnection* dbConn = GetConstDBConn();
+    NS_ENSURE_TRUE(dbConn, nullptr);
+    return mDB->GetStatement(aQuery);
+  }
+
+  already_AddRefed<mozIStorageStatement> GetStatement(
+      const nsACString& aQuery) {
+    // May be invoked on both threads.
+    const mozIStorageConnection* dbConn = GetConstDBConn();
+    NS_ENSURE_TRUE(dbConn, nullptr);
+    return mDB->GetStatement(aQuery);
+  }
+
+  bool IsShuttingDown() {
+    MutexAutoLock lockedScope(mShuttingDownMutex);
+    return mShuttingDown;
+  }
+
+  /**
+   * Helper function to append a new URI to mRecentlyVisitedURIs. See
+   * mRecentlyVisitedURIs.
+   * @param {nsIURI} aURI The URI to append
+   * @param {bool} aHidden The hidden status of the visit being appended.
+   */
+  void AppendToRecentlyVisitedURIs(nsIURI* aURI, bool aHidden);
+
+ private:
+  virtual ~History();
+
+  void InitMemoryReporter();
+
+  /**
+   * Obtains a read-write database connection, initializing the connection
+   * if needed. Must be invoked on the main thread.
+   */
+  mozIStorageConnection* GetDBConn();
+
+  /**
+   * Obtains a read-write database connection, but won't try to initialize it.
+   * May be invoked on both threads, but first one must invoke GetDBConn() on
+   * the main-thread at least once.
+   */
+  const mozIStorageConnection* GetConstDBConn();
+
+  /**
+   * The database handle.  This is initialized lazily by the first call to
+   * GetDBConn(), so never use it directly, or, if you really need, always
+   * invoke GetDBConn() before.
+   */
+  RefPtr<mozilla::places::Database> mDB;
+
+  RefPtr<ConcurrentStatementsHolder> mConcurrentStatementsHolder;
+
+  /**
+   * Remove any memory references to tasks and do not take on any more.
+   */
+  void Shutdown();
+
+  static History* gService;
+
+  // Ensures new tasks aren't started on destruction. Should only be changed on
+  // the main thread.
+  bool mShuttingDown;
+  // This mutex guards mShuttingDown and should be acquired on the helper
+  // thread.
+  Mutex mShuttingDownMutex MOZ_UNANNOTATED;
+  // Code running in the helper thread can acquire this mutex to block shutdown
+  // from proceeding until done, otherwise it may be impossible to get
+  // statements to execute and an insert operation could be interrupted in the
+  // middle.
+  Mutex mBlockShutdownMutex MOZ_UNANNOTATED;
+
+  // Allow private access from the helper thread to acquire mutexes.
+  friend class InsertVisitedURIs;
+
+  /**
+   * mRecentlyVisitedURIs remembers URIs which have been recently added to
+   * history, to avoid saving these locations repeatedly in a short period.
+   */
+  struct RecentURIVisit {
+    PRTime mTime;
+    bool mHidden;
+  };
+
+  nsTHashMap<nsURIHashKey, RecentURIVisit> mRecentlyVisitedURIs;
+};
+
+}  // namespace mozilla::places
+
+#endif  // mozilla_places_History_h_
diff --git a/toolkit/components/places/History.sys.mjs b/toolkit/components/places/History.sys.mjs
new file mode 100644
index 0000000000..3f43ca5a53
--- /dev/null
+++ b/toolkit/components/places/History.sys.mjs
@@ -0,0 +1,1741 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Asynchronous API for managing history.
+ *
+ *
+ * The API makes use of `PageInfo` and `VisitInfo` objects, defined as follows.
+ *
+ * A `PageInfo` object is any object that contains A SUBSET of the
+ * following properties:
+ * - guid: (string)
+ *     The globally unique id of the page.
+ * - url: (URL)
+ *     or (nsIURI)
+ *     or (string)
+ *     The full URI of the page. Note that `PageInfo` values passed as
+ *     argument may hold `nsIURI` or `string` values for property `url`,
+ *     but `PageInfo` objects returned by this module always hold `URL`
+ *     values.
+ * - title: (string)
+ *     The title associated with the page, if any.
+ * - description: (string)
+ *     The description of the page, if any.
+ * - previewImageURL: (URL)
+ *     or (nsIURI)
+ *     or (string)
+ *     The preview image URL of the page, if any.
+ * - frecency: (number)
+ *     The frecency of the page, if any.
+ *     See https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Places/Frecency_algorithm
+ *     Note that this property may not be used to change the actualy frecency
+ *     score of a page, only to retrieve it. In other words, any `frecency` field
+ *     passed as argument to a function of this API will be ignored.
+ *  - visits: (Array<VisitInfo>)
+ *     All the visits for this page, if any.
+ *  - annotations: (Map)
+ *     A map containing key/value pairs of the annotations for this page, if any.
+ *
+ * See the documentation of individual methods to find out which properties
+ * are required for `PageInfo` arguments or returned for `PageInfo` results.
+ *
+ * A `VisitInfo` object is any object that contains A SUBSET of the following
+ * properties:
+ * - date: (Date)
+ *     The time the visit occurred.
+ * - transition: (number)
+ *     How the user reached the page. See constants `TRANSITIONS.*`
+ *     for the possible transition types.
+ * - referrer: (URL)
+ *          or (nsIURI)
+ *          or (string)
+ *     The referring URI of this visit. Note that `VisitInfo` passed
+ *     as argument may hold `nsIURI` or `string` values for property `referrer`,
+ *     but `VisitInfo` objects returned by this module always hold `URL`
+ *     values.
+ * See the documentation of individual methods to find out which properties
+ * are required for `VisitInfo` arguments or returned for `VisitInfo` results.
+ *
+ *
+ *
+ * Each successful operation notifies through the PlacesObservers. To listen to such
+ * notifications you must register using
+ * PlacesObservers `addListener` and `removeListener` methods.
+ * @see PlacesObservers
+ */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "asyncHistory",
+  "@mozilla.org/browser/history;1",
+  "mozIAsyncHistory"
+);
+
+/**
+ * Whenever we update numerous pages, it is preferable to yield time to the main
+ * thread every so often to avoid janking.
+ * These constants determine the maximal number of notifications we
+ * may emit before we yield.
+ */
+const ONRESULT_CHUNK_SIZE = 300;
+
+// This constant determines the maximum number of remove pages before we cycle.
+const REMOVE_PAGES_CHUNKLEN = 300;
+
+export var History = Object.freeze({
+  ANNOTATION_EXPIRE_NEVER: 4,
+  // Constants for the type of annotation.
+  ANNOTATION_TYPE_STRING: 3,
+  ANNOTATION_TYPE_INT64: 5,
+
+  /**
+   * Fetch the available information for one page.
+   *
+   * @param {URL|nsIURI|string} guidOrURI: (string) or (URL, nsIURI or href)
+   *      Either the full URI of the page or the GUID of the page.
+   * @param {object} [options]
+   *      An optional object whose properties describe options:
+   *        - `includeVisits` (boolean) set this to true if `visits` in the
+   *           PageInfo needs to contain VisitInfo in a reverse chronological order.
+   *           By default, `visits` is undefined inside the returned `PageInfo`.
+   *        - `includeMeta` (boolean) set this to true to fetch page meta fields,
+   *           i.e. `description`, `site_name` and `preview_image_url`.
+   *        - `includeAnnotations` (boolean) set this to true to fetch any
+   *           annotations that are associated with the page.
+   *
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolves (PageInfo | null) If the page could be found, the information
+   *      on that page.
+   * @note the VisitInfo objects returned while fetching visits do not
+   *       contain the property `referrer`.
+   *       TODO: Add `referrer` to VisitInfo. See Bug #1365913.
+   * @note the visits returned will not contain `TRANSITION_EMBED` visits.
+   *
+   * @throws (Error)
+   *      If `guidOrURI` does not have the expected type or if it is a string
+   *      that may be parsed neither as a valid URL nor as a valid GUID.
+   */
+  fetch(guidOrURI, options = {}) {
+    // First, normalize to guid or string, and throw if not possible
+    guidOrURI = lazy.PlacesUtils.normalizeToURLOrGUID(guidOrURI);
+
+    // See if options exists and make sense
+    if (!options || typeof options !== "object") {
+      throw new TypeError("options should be an object and not null");
+    }
+
+    let hasIncludeVisits = "includeVisits" in options;
+    if (hasIncludeVisits && typeof options.includeVisits !== "boolean") {
+      throw new TypeError("includeVisits should be a boolean if exists");
+    }
+
+    let hasIncludeMeta = "includeMeta" in options;
+    if (hasIncludeMeta && typeof options.includeMeta !== "boolean") {
+      throw new TypeError("includeMeta should be a boolean if exists");
+    }
+
+    let hasIncludeAnnotations = "includeAnnotations" in options;
+    if (
+      hasIncludeAnnotations &&
+      typeof options.includeAnnotations !== "boolean"
+    ) {
+      throw new TypeError("includeAnnotations should be a boolean if exists");
+    }
+
+    return lazy.PlacesUtils.promiseDBConnection().then(db =>
+      fetch(db, guidOrURI, options)
+    );
+  },
+
+  /**
+   * Fetches all pages which have one or more of the specified annotations.
+   *
+   * @param annotations: An array of strings containing the annotation names to
+   *                     find.
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolves (Map)
+   *      A Map containing the annotations, pages and their contents, e.g.
+   *      Map("anno1" => [{page, content}, {page, content}]), "anno2" => ....);
+   * @rejects (Error) XXX
+   *      Rejects if the insert was unsuccessful.
+   */
+  fetchAnnotatedPages(annotations) {
+    // See if options exists and make sense
+    if (!annotations || !Array.isArray(annotations)) {
+      throw new TypeError("annotations should be an Array and not null");
+    }
+    if (annotations.some(name => typeof name !== "string")) {
+      throw new TypeError("all annotation values should be strings");
+    }
+
+    return lazy.PlacesUtils.promiseDBConnection().then(db =>
+      fetchAnnotatedPages(db, annotations)
+    );
+  },
+
+  /**
+   * Fetch multiple pages.
+   *
+   * @param {string[]|nsIURI[]|URL[]} guidOrURIs: Array of href or URLs to fetch.
+   * @returns {Promise}
+   *   A promise resolved once the operation is complete.
+   * @resolves {Map<string, string>} Map of PageInfos, keyed by the input info,
+   *   either guid or href. We don't use nsIURI or URL as keys to avoid
+   *   complexity, in all the cases the caller knows which objects is handling,
+   *   and can unwrap them. Unknown input pages will have no entry in the Map.
+   * @throws (Error)
+   *   If input is invalid, for example not a valid GUID or URL.
+   */
+  fetchMany(guidOrURIs) {
+    if (!Array.isArray(guidOrURIs)) {
+      throw new TypeError("Input is not an array");
+    }
+    // First, normalize to guid or URL, throw if not possible
+    guidOrURIs = guidOrURIs.map(v => lazy.PlacesUtils.normalizeToURLOrGUID(v));
+    return lazy.PlacesUtils.promiseDBConnection().then(db =>
+      fetchMany(db, guidOrURIs)
+    );
+  },
+
+  /**
+   * Adds a number of visits for a single page.
+   *
+   * Any change may be observed through PlacesObservers.
+   *
+   * @param pageInfo: (PageInfo)
+   *      Information on a page. This `PageInfo` MUST contain
+   *        - a property `url`, as specified by the definition of `PageInfo`.
+   *        - a property `visits`, as specified by the definition of
+   *          `PageInfo`, which MUST contain at least one visit.
+   *      If a property `title` is provided, the title of the page
+   *      is updated.
+   *      If the `date` of a visit is not provided, it defaults
+   *      to now.
+   *      If the `transition` of a visit is not provided, it defaults to
+   *      TRANSITION_LINK.
+   *
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolves (PageInfo)
+   *      A PageInfo object populated with data after the insert is complete.
+   * @rejects (Error)
+   *      Rejects if the insert was unsuccessful.
+   *
+   * @throws (Error)
+   *      If the `url` specified was for a protocol that should not be
+   *      stored (@see nsNavHistory::CanAddURI).
+   * @throws (Error)
+   *      If `pageInfo` has an unexpected type.
+   * @throws (Error)
+   *      If `pageInfo` does not have a `url`.
+   * @throws (Error)
+   *      If `pageInfo` does not have a `visits` property or if the
+   *      value of `visits` is ill-typed or is an empty array.
+   * @throws (Error)
+   *      If an element of `visits` has an invalid `date`.
+   * @throws (Error)
+   *      If an element of `visits` has an invalid `transition`.
+   */
+  insert(pageInfo) {
+    let info = lazy.PlacesUtils.validatePageInfo(pageInfo);
+
+    return lazy.PlacesUtils.withConnectionWrapper("History.jsm: insert", db =>
+      insert(db, info)
+    );
+  },
+
+  /**
+   * Adds a number of visits for a number of pages.
+   *
+   * Any change may be observed through PlacesObservers.
+   *
+   * @param pageInfos: (Array<PageInfo>)
+   *      Information on a page. This `PageInfo` MUST contain
+   *        - a property `url`, as specified by the definition of `PageInfo`.
+   *        - a property `visits`, as specified by the definition of
+   *          `PageInfo`, which MUST contain at least one visit.
+   *      If a property `title` is provided, the title of the page
+   *      is updated.
+   *      If the `date` of a visit is not provided, it defaults
+   *      to now.
+   *      If the `transition` of a visit is not provided, it defaults to
+   *      TRANSITION_LINK.
+   * @param onResult: (function(PageInfo))
+   *      A callback invoked for each page inserted.
+   * @param onError: (function(PageInfo))
+   *      A callback invoked for each page which generated an error
+   *      when an insert was attempted.
+   *
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolves (null)
+   * @rejects (Error)
+   *      Rejects if all of the inserts were unsuccessful.
+   *
+   * @throws (Error)
+   *      If the `url` specified was for a protocol that should not be
+   *      stored (@see nsNavHistory::CanAddURI).
+   * @throws (Error)
+   *      If `pageInfos` has an unexpected type.
+   * @throws (Error)
+   *      If a `pageInfo` does not have a `url`.
+   * @throws (Error)
+   *      If a `PageInfo` does not have a `visits` property or if the
+   *      value of `visits` is ill-typed or is an empty array.
+   * @throws (Error)
+   *      If an element of `visits` has an invalid `date`.
+   * @throws (Error)
+   *      If an element of `visits` has an invalid `transition`.
+   */
+  insertMany(pageInfos, onResult, onError) {
+    let infos = [];
+
+    if (!Array.isArray(pageInfos)) {
+      throw new TypeError("pageInfos must be an array");
+    }
+    if (!pageInfos.length) {
+      throw new TypeError("pageInfos may not be an empty array");
+    }
+
+    if (onResult && typeof onResult != "function") {
+      throw new TypeError(`onResult: ${onResult} is not a valid function`);
+    }
+    if (onError && typeof onError != "function") {
+      throw new TypeError(`onError: ${onError} is not a valid function`);
+    }
+
+    for (let pageInfo of pageInfos) {
+      let info = lazy.PlacesUtils.validatePageInfo(pageInfo);
+      infos.push(info);
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "History.jsm: insertMany",
+      db => insertMany(db, infos, onResult, onError)
+    );
+  },
+
+  /**
+   * Remove pages from the database.
+   *
+   * Any change may be observed through PlacesObservers.
+   *
+   *
+   * @param page: (URL or nsIURI)
+   *      The full URI of the page.
+   *             or (string)
+   *      Either the full URI of the page or the GUID of the page.
+   *             or (Array<URL|nsIURI|string>)
+   *      An array of the above, to batch requests.
+   * @param onResult: (function(PageInfo))
+   *      A callback invoked for each page found.
+   *
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolve (bool)
+   *      `true` if at least one page was removed, `false` otherwise.
+   * @throws (TypeError)
+   *       If `pages` has an unexpected type or if a string provided
+   *       is neither a valid GUID nor a valid URI or if `pages`
+   *       is an empty array.
+   */
+  remove(pages, onResult = null) {
+    // Normalize and type-check arguments
+    if (Array.isArray(pages)) {
+      if (!pages.length) {
+        throw new TypeError("Expected at least one page");
+      }
+    } else {
+      pages = [pages];
+    }
+
+    let guids = [];
+    let urls = [];
+    for (let page of pages) {
+      // Normalize to URL or GUID, or throw if `page` cannot
+      // be normalized.
+      let normalized = lazy.PlacesUtils.normalizeToURLOrGUID(page);
+      if (typeof normalized === "string") {
+        guids.push(normalized);
+      } else {
+        urls.push(normalized.href);
+      }
+    }
+
+    // At this stage, we know that either `guids` is not-empty
+    // or `urls` is not-empty.
+
+    if (onResult && typeof onResult != "function") {
+      throw new TypeError("Invalid function: " + onResult);
+    }
+
+    return (async function () {
+      let removedPages = false;
+      let count = 0;
+      while (guids.length || urls.length) {
+        if (count && count % 2 == 0) {
+          // Every few cycles, yield time back to the main
+          // thread to avoid jank.
+          await Promise.resolve();
+        }
+        count++;
+        let guidsSlice = guids.splice(0, REMOVE_PAGES_CHUNKLEN);
+        let urlsSlice = [];
+        if (guidsSlice.length < REMOVE_PAGES_CHUNKLEN) {
+          urlsSlice = urls.splice(0, REMOVE_PAGES_CHUNKLEN - guidsSlice.length);
+        }
+
+        let pages = { guids: guidsSlice, urls: urlsSlice };
+
+        let result = await lazy.PlacesUtils.withConnectionWrapper(
+          "History.jsm: remove",
+          db => remove(db, pages, onResult)
+        );
+
+        removedPages = removedPages || result;
+      }
+      return removedPages;
+    })();
+  },
+
+  /**
+   * Remove visits matching specific characteristics.
+   *
+   * Any change may be observed through PlacesObservers.
+   *
+   * @param filter: (object)
+   *      The `object` may contain some of the following
+   *      properties:
+   *          - beginDate: (Date) Remove visits that have
+   *                been added since this date (inclusive).
+   *          - endDate: (Date) Remove visits that have
+   *                been added before this date (inclusive).
+   *          - limit: (Number) Limit the number of visits
+   *                we remove to this number
+   *          - url: (URL) Only remove visits to this URL
+   *          - transition: (Integer)
+   *                The type of the transition (see TRANSITIONS below)
+   *      If both `beginDate` and `endDate` are specified,
+   *      visits between `beginDate` (inclusive) and `end`
+   *      (inclusive) are removed.
+   *
+   * @param onResult: (function(VisitInfo), [optional])
+   *     A callback invoked for each visit found and removed.
+   *     Note that the referrer property of `VisitInfo`
+   *     is NOT populated.
+   *
+   * @return (Promise)
+   * @resolve (bool)
+   *      `true` if at least one visit was removed, `false`
+   *      otherwise.
+   * @throws (TypeError)
+   *      If `filter` does not have the expected type, in
+   *      particular if the `object` is empty.
+   */
+  removeVisitsByFilter(filter, onResult = null) {
+    if (!filter || typeof filter != "object") {
+      throw new TypeError("Expected a filter");
+    }
+
+    let hasBeginDate = "beginDate" in filter;
+    let hasEndDate = "endDate" in filter;
+    let hasURL = "url" in filter;
+    let hasLimit = "limit" in filter;
+    let hasTransition = "transition" in filter;
+    if (hasBeginDate) {
+      this.ensureDate(filter.beginDate);
+    }
+    if (hasEndDate) {
+      this.ensureDate(filter.endDate);
+    }
+    if (hasBeginDate && hasEndDate && filter.beginDate > filter.endDate) {
+      throw new TypeError("`beginDate` should be at least as old as `endDate`");
+    }
+    if (hasTransition && !this.isValidTransition(filter.transition)) {
+      throw new TypeError("`transition` should be valid");
+    }
+    if (
+      !hasBeginDate &&
+      !hasEndDate &&
+      !hasURL &&
+      !hasLimit &&
+      !hasTransition
+    ) {
+      throw new TypeError("Expected a non-empty filter");
+    }
+
+    if (
+      hasURL &&
+      !URL.isInstance(filter.url) &&
+      typeof filter.url != "string" &&
+      !(filter.url instanceof Ci.nsIURI)
+    ) {
+      throw new TypeError("Expected a valid URL for `url`");
+    }
+
+    if (
+      hasLimit &&
+      (typeof filter.limit != "number" ||
+        filter.limit <= 0 ||
+        !Number.isInteger(filter.limit))
+    ) {
+      throw new TypeError("Expected a non-zero positive integer as a limit");
+    }
+
+    if (onResult && typeof onResult != "function") {
+      throw new TypeError("Invalid function: " + onResult);
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "History.jsm: removeVisitsByFilter",
+      db => removeVisitsByFilter(db, filter, onResult)
+    );
+  },
+
+  /**
+   * Remove pages from the database based on a filter.
+   *
+   * Any change may be observed through PlacesObservers
+   *
+   *
+   * @param filter: An object containing a non empty subset of the following
+   * properties:
+   * - host: (string)
+   *     Hostname with or without subhost. Examples:
+   *       "mozilla.org" removes pages from mozilla.org but not its subdomains
+   *       ".mozilla.org" removes pages from mozilla.org and its subdomains
+   *       "." removes local files
+   * - beginDate: (Date)
+   *     The first time the page was visited (inclusive)
+   * - endDate: (Date)
+   *     The last time the page was visited (inclusive)
+   * @param [optional] onResult: (function(PageInfo))
+   *      A callback invoked for each page found.
+   *
+   * @note This removes pages with at least one visit inside the timeframe.
+   *       Any visits outside the timeframe will also be removed with the page.
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolve (bool)
+   *      `true` if at least one page was removed, `false` otherwise.
+   * @throws (TypeError)
+   *       if `filter` does not have the expected type, in particular
+   *       if the `object` is empty, or its components do not satisfy the
+   *       criteria given above
+   */
+  removeByFilter(filter, onResult) {
+    if (!filter || typeof filter !== "object") {
+      throw new TypeError("Expected a filter object");
+    }
+
+    let hasHost = filter.host;
+    if (hasHost) {
+      if (typeof filter.host !== "string") {
+        throw new TypeError("`host` should be a string");
+      }
+      filter.host = filter.host.toLowerCase();
+      if (filter.host.length > 1 && filter.host.lastIndexOf(".") == 0) {
+        // The input contains only an initial period, thus it may be a
+        // wildcarded local host, like ".localhost". Ideally the consumer should
+        // pass just "localhost", because there is no concept of subhosts for
+        // it, but we are being more lenient to allow for simpler input.
+        // Anyway, in this case we remove the wildcard to avoid clearing too
+        // much if the consumer wrongly passes in things like ".com".
+        filter.host = filter.host.slice(1);
+      }
+    }
+
+    let hasBeginDate = "beginDate" in filter;
+    if (hasBeginDate) {
+      this.ensureDate(filter.beginDate);
+    }
+
+    let hasEndDate = "endDate" in filter;
+    if (hasEndDate) {
+      this.ensureDate(filter.endDate);
+    }
+
+    if (hasBeginDate && hasEndDate && filter.beginDate > filter.endDate) {
+      throw new TypeError("`beginDate` should be at least as old as `endDate`");
+    }
+
+    if (!hasBeginDate && !hasEndDate && !hasHost) {
+      throw new TypeError("Expected a non-empty filter");
+    }
+
+    // Check the host format.
+    // Either it has no dots, or has multiple dots, or it's a single dot char.
+    if (
+      hasHost &&
+      (!/^(\.?([.a-z0-9-]+\.[a-z0-9-]+)?|[a-z0-9-]+)$/.test(filter.host) ||
+        filter.host.includes(".."))
+    ) {
+      throw new TypeError(
+        "Expected well formed hostname string for `host` with atmost 1 wildcard."
+      );
+    }
+
+    if (onResult && typeof onResult != "function") {
+      throw new TypeError("Invalid function: " + onResult);
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "History.jsm: removeByFilter",
+      db => removeByFilter(db, filter, onResult)
+    );
+  },
+
+  /**
+   * Determine if a page has been visited.
+   *
+   * @param guidOrURI: (string) or (URL, nsIURI or href)
+   *      Either the full URI of the page or the GUID of the page.
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   * @resolve (bool)
+   *      `true` if the page has been visited, `false` otherwise.
+   * @throws (Error)
+   *      If `guidOrURI` has an unexpected type or if a string provided
+   *      is neither not a valid GUID nor a valid URI.
+   */
+  hasVisits(guidOrURI) {
+    // Quick fallback to the cpp version.
+    if (guidOrURI instanceof Ci.nsIURI) {
+      return new Promise(resolve => {
+        lazy.asyncHistory.isURIVisited(guidOrURI, (aURI, aIsVisited) => {
+          resolve(aIsVisited);
+        });
+      });
+    }
+
+    guidOrURI = lazy.PlacesUtils.normalizeToURLOrGUID(guidOrURI);
+    let isGuid = typeof guidOrURI == "string";
+    let sqlFragment = isGuid
+      ? "guid = :val"
+      : "url_hash = hash(:val) AND url = :val ";
+
+    return lazy.PlacesUtils.promiseDBConnection().then(async db => {
+      let rows = await db.executeCached(
+        `SELECT 1 FROM moz_places
+                                         WHERE ${sqlFragment}
+                                         AND last_visit_date NOTNULL`,
+        { val: isGuid ? guidOrURI : guidOrURI.href }
+      );
+      return !!rows.length;
+    });
+  },
+
+  /**
+   * Clear all history.
+   *
+   * @return (Promise)
+   *      A promise resolved once the operation is complete.
+   */
+  clear() {
+    return lazy.PlacesUtils.withConnectionWrapper("History.jsm: clear", clear);
+  },
+
+  /**
+   * Is a value a valid transition type?
+   *
+   * @param transition: (String)
+   * @return (Boolean)
+   */
+  isValidTransition(transition) {
+    return Object.values(History.TRANSITIONS).includes(transition);
+  },
+
+  /**
+   * Throw if an object is not a Date object.
+   */
+  ensureDate(arg) {
+    if (
+      !arg ||
+      typeof arg != "object" ||
+      arg.constructor.name != "Date" ||
+      isNaN(arg)
+    ) {
+      throw new TypeError("Expected a valid Date, got " + arg);
+    }
+  },
+
+  /**
+   * Update information for a page.
+   *
+   * Currently, it supports updating the description, preview image URL and annotations
+   * for a page, any other fields will be ignored.
+   *
+   * Note that this function will ignore the update if the target page has not
+   * yet been stored in the database. `History.fetch` could be used to check
+   * whether the page and its meta information exist or not. Beware that
+   * fetch&update might fail as they are not executed in a single transaction.
+   *
+   * @param pageInfo: (PageInfo)
+   *      pageInfo must contain a URL of the target page. It will be ignored
+   *      if a valid page `guid` is also provided.
+   *
+   *      If a property `description` is provided, the description of the
+   *      page is updated. Note that:
+   *      1). An empty string or null `description` will clear the existing
+   *          value in the database.
+   *      2). Descriptions longer than DB_DESCRIPTION_LENGTH_MAX will be
+   *          truncated.
+   *
+   *      If a property `siteName` is provided, the site name of the
+   *      page is updated. Note that:
+   *      1). An empty string or null `siteName` will clear the existing
+   *          value in the database.
+   *      2). Descriptions longer than DB_SITENAME_LENGTH_MAX will be
+   *          truncated.
+   *
+   *      If a property `previewImageURL` is provided, the preview image
+   *      URL of the page is updated. Note that:
+   *      1). A null `previewImageURL` will clear the existing value in the
+   *          database.
+   *      2). It throws if its length is greater than DB_URL_LENGTH_MAX
+   *          defined in PlacesUtils.jsm.
+   *
+   *      If a property `annotations` is provided, the annotations will be
+   *      updated. Note that:
+   *      1). It should be a Map containing key/value pairs to be updated.
+   *      2). If the value is falsy, the annotation will be removed.
+   *      3). If the value is non-falsy, the annotation will be added or updated.
+   *      For `annotations` the keys must all be strings, the values should be
+   *      Boolean, Number or Strings. null and undefined are supported as falsy values.
+   *
+   * @return (Promise)
+   *      A promise resolved once the update is complete.
+   * @rejects (Error)
+   *      Rejects if the update was unsuccessful.
+   *
+   * @throws (Error)
+   *      If `pageInfo` has an unexpected type.
+   * @throws (Error)
+   *      If `pageInfo` has an invalid `url` or an invalid `guid`.
+   * @throws (Error)
+   *      If `pageInfo` has neither `description` nor `previewImageURL`.
+   * @throws (Error)
+   *      If the length of `pageInfo.previewImageURL` is greater than
+   *      DB_URL_LENGTH_MAX defined in PlacesUtils.jsm.
+   */
+  update(pageInfo) {
+    let info = lazy.PlacesUtils.validatePageInfo(pageInfo, false);
+
+    if (
+      info.description === undefined &&
+      info.siteName === undefined &&
+      info.previewImageURL === undefined &&
+      info.annotations === undefined
+    ) {
+      throw new TypeError(
+        "pageInfo object must at least have either a description, siteName, previewImageURL or annotations property."
+      );
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper("History.jsm: update", db =>
+      update(db, info)
+    );
+  },
+
+  /**
+   * Possible values for the `transition` property of `VisitInfo`
+   * objects.
+   */
+
+  TRANSITIONS: {
+    /**
+     * The user followed a link and got a new toplevel window.
+     */
+    LINK: Ci.nsINavHistoryService.TRANSITION_LINK,
+
+    /**
+     * The user typed the page's URL in the URL bar or selected it from
+     * URL bar autocomplete results, clicked on it from a history query
+     * (from the History sidebar, History menu, or history query in the
+     * personal toolbar or Places organizer.
+     */
+    TYPED: Ci.nsINavHistoryService.TRANSITION_TYPED,
+
+    /**
+     * The user followed a bookmark to get to the page.
+     */
+    BOOKMARK: Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+
+    /**
+     * Some inner content is loaded. This is true of all images on a
+     * page, and the contents of the iframe. It is also true of any
+     * content in a frame if the user did not explicitly follow a link
+     * to get there.
+     */
+    EMBED: Ci.nsINavHistoryService.TRANSITION_EMBED,
+
+    /**
+     * Set when the transition was a permanent redirect.
+     */
+    REDIRECT_PERMANENT: Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT,
+
+    /**
+     * Set when the transition was a temporary redirect.
+     */
+    REDIRECT_TEMPORARY: Ci.nsINavHistoryService.TRANSITION_REDIRECT_TEMPORARY,
+
+    /**
+     * Set when the transition is a download.
+     */
+    DOWNLOAD: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+
+    /**
+     * The user followed a link and got a visit in a frame.
+     */
+    FRAMED_LINK: Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK,
+
+    /**
+     * The user reloaded a page.
+     */
+    RELOAD: Ci.nsINavHistoryService.TRANSITION_RELOAD,
+  },
+});
+
+/**
+ * Convert a PageInfo object into the format expected by updatePlaces.
+ *
+ * Note: this assumes that the PageInfo object has already been validated
+ * via PlacesUtils.validatePageInfo.
+ *
+ * @param pageInfo: (PageInfo)
+ * @return (info)
+ */
+function convertForUpdatePlaces(pageInfo) {
+  let info = {
+    guid: pageInfo.guid,
+    uri: lazy.PlacesUtils.toURI(pageInfo.url),
+    title: pageInfo.title,
+    visits: [],
+  };
+
+  for (let inVisit of pageInfo.visits) {
+    let visit = {
+      visitDate: lazy.PlacesUtils.toPRTime(inVisit.date),
+      transitionType: inVisit.transition,
+      referrerURI: inVisit.referrer
+        ? lazy.PlacesUtils.toURI(inVisit.referrer)
+        : undefined,
+    };
+    info.visits.push(visit);
+  }
+  return info;
+}
+
+// Inner implementation of History.clear().
+var clear = async function (db) {
+  await db.executeTransaction(async function () {
+    // Since all metadata must be removed, remove it before pages, to save on
+    // foreign key delete cascading.
+    await db.execute("DELETE FROM moz_places_metadata");
+
+    // Remove all non-bookmarked places entries first, this will speed up the
+    // triggers work.
+    await db.execute(`DELETE FROM moz_places WHERE foreign_count = 0`);
+    await db.execute(`DELETE FROM moz_updateoriginsdelete_temp`);
+
+    // Expire orphan icons.
+    await db.executeCached(`DELETE FROM moz_pages_w_icons
+                            WHERE page_url_hash NOT IN (SELECT url_hash FROM moz_places)`);
+    await removeOrphanIcons(db);
+
+    // Expire annotations.
+    await db.execute(`DELETE FROM moz_annos WHERE NOT EXISTS (
+                        SELECT 1 FROM moz_places WHERE id = place_id
+                      )`);
+
+    // Expire inputhistory.
+    await db.execute(`DELETE FROM moz_inputhistory WHERE place_id IN (
+                        SELECT i.place_id FROM moz_inputhistory i
+                        LEFT JOIN moz_places h ON h.id = i.place_id
+                        WHERE h.id IS NULL)`);
+
+    // Remove all history.
+    await db.execute("DELETE FROM moz_historyvisits");
+  });
+
+  PlacesObservers.notifyListeners([new PlacesHistoryCleared()]);
+};
+
+/**
+ * Clean up pages whose history has been modified, by either
+ * removing them entirely (if they are marked for removal,
+ * typically because all visits have been removed and there
+ * are no more foreign keys such as bookmarks) or updating
+ * their frecency (otherwise).
+ *
+ * @param db: (Sqlite connection)
+ *      The database.
+ * @param pages: (Array of objects)
+ *      Pages that have been touched and that need cleaning up.
+ *      Each object should have the following properties:
+ *          - id: (number) The `moz_places` identifier for the place.
+ *          - hasVisits: (boolean) If `true`, there remains at least one
+ *              visit to this page, so the page should be kept and its
+ *              frecency updated.
+ *          - hasForeign: (boolean) If `true`, the page has at least
+ *              one foreign reference (i.e. a bookmark), so the page should
+ *              be kept and its frecency updated.
+ * @return (Promise)
+ */
+var cleanupPages = async function (db, pages) {
+  let pagesToRemove = pages.filter(p => !p.hasForeign && !p.hasVisits);
+  if (!pagesToRemove.length) {
+    return;
+  }
+
+  // Note, we are already in a transaction, since callers create it.
+  // Check relations regardless, to avoid creating orphans in case of
+  // async race conditions.
+  for (let chunk of lazy.PlacesUtils.chunkArray(
+    pagesToRemove,
+    db.variableLimit
+  )) {
+    let idsToRemove = chunk.map(p => p.id);
+    await db.execute(
+      `DELETE FROM moz_places
+       WHERE id IN ( ${lazy.PlacesUtils.sqlBindPlaceholders(idsToRemove)} )
+         AND foreign_count = 0 AND last_visit_date ISNULL`,
+      idsToRemove
+    );
+
+    // Expire orphans.
+    let hashesToRemove = chunk.map(p => p.hash);
+    await db.executeCached(
+      `DELETE FROM moz_pages_w_icons
+       WHERE page_url_hash IN (${lazy.PlacesUtils.sqlBindPlaceholders(
+         hashesToRemove
+       )})`,
+      hashesToRemove
+    );
+
+    await db.execute(
+      `DELETE FROM moz_annos
+       WHERE place_id IN ( ${lazy.PlacesUtils.sqlBindPlaceholders(
+         idsToRemove
+       )} )`,
+      idsToRemove
+    );
+    await db.execute(
+      `DELETE FROM moz_inputhistory
+       WHERE place_id IN ( ${lazy.PlacesUtils.sqlBindPlaceholders(
+         idsToRemove
+       )} )`,
+      idsToRemove
+    );
+  }
+  // Hosts accumulated during the places delete are updated through a trigger
+  // (see nsPlacesTriggers.h).
+  await db.executeCached(`DELETE FROM moz_updateoriginsdelete_temp`);
+
+  await removeOrphanIcons(db);
+};
+
+/**
+ * Remove icons whose origin is not in moz_origins, unless referenced.
+ * @param db: (Sqlite connection)
+ *      The database.
+ */
+function removeOrphanIcons(db) {
+  return db.executeCached(`
+    DELETE FROM moz_icons WHERE id IN (
+      SELECT id FROM moz_icons WHERE root = 0
+      UNION ALL
+      SELECT id FROM moz_icons
+      WHERE root = 1
+        AND get_host_and_port(icon_url) NOT IN (SELECT host FROM moz_origins)
+        AND fixup_url(get_host_and_port(icon_url)) NOT IN (SELECT host FROM moz_origins)
+      EXCEPT
+      SELECT icon_id FROM moz_icons_to_pages
+    )`);
+}
+
+/**
+ * Notify observers that pages have been removed/updated.
+ *
+ * @param db: (Sqlite connection)
+ *      The database.
+ * @param pages: (Array of objects)
+ *      Pages that have been touched and that need cleaning up.
+ *      Each object should have the following properties:
+ *          - id: (number) The `moz_places` identifier for the place.
+ *          - hasVisits: (boolean) If `true`, there remains at least one
+ *              visit to this page, so the page should be kept and its
+ *              frecency updated.
+ *          - hasForeign: (boolean) If `true`, the page has at least
+ *              one foreign reference (i.e. a bookmark), so the page should
+ *              be kept and its frecency updated.
+ * @param transitionType: (Number)
+ *      Set to a valid TRANSITIONS value to indicate all transitions of a
+ *      certain type have been removed, otherwise defaults to 0 (unknown value).
+ * @return (Promise)
+ */
+var notifyCleanup = async function (db, pages, transitionType = 0) {
+  const notifications = [];
+
+  for (let page of pages) {
+    const isRemovedFromStore = !page.hasVisits && !page.hasForeign;
+    notifications.push(
+      new PlacesVisitRemoved({
+        url: page.url.href,
+        pageGuid: page.guid,
+        reason: PlacesVisitRemoved.REASON_DELETED,
+        transitionType,
+        isRemovedFromStore,
+        isPartialVisistsRemoval: !isRemovedFromStore && page.hasVisits > 0,
+      })
+    );
+  }
+
+  PlacesObservers.notifyListeners(notifications);
+};
+
+/**
+ * Notify an `onResult` callback of a set of operations
+ * that just took place.
+ *
+ * @param data: (Array)
+ *      The data to send to the callback.
+ * @param onResult: (function [optional])
+ *      If provided, call `onResult` with `data[0]`, `data[1]`, etc.
+ *      Otherwise, do nothing.
+ */
+var notifyOnResult = async function (data, onResult) {
+  if (!onResult) {
+    return;
+  }
+  let notifiedCount = 0;
+  for (let info of data) {
+    try {
+      onResult(info);
+    } catch (ex) {
+      // Errors should be reported but should not stop the operation.
+      Promise.reject(ex);
+    }
+    if (++notifiedCount % ONRESULT_CHUNK_SIZE == 0) {
+      // Every few notifications, yield time back to the main
+      // thread to avoid jank.
+      await Promise.resolve();
+    }
+  }
+};
+
+// Inner implementation of History.fetch.
+var fetch = async function (db, guidOrURL, options) {
+  let whereClauseFragment = "";
+  let params = {};
+  if (URL.isInstance(guidOrURL)) {
+    whereClauseFragment = "WHERE h.url_hash = hash(:url) AND h.url = :url";
+    params.url = guidOrURL.href;
+  } else {
+    whereClauseFragment = "WHERE h.guid = :guid";
+    params.guid = guidOrURL;
+  }
+
+  let visitSelectionFragment = "";
+  let joinFragment = "";
+  let visitOrderFragment = "";
+  if (options.includeVisits) {
+    visitSelectionFragment = ", v.visit_date, v.visit_type";
+    joinFragment = "JOIN moz_historyvisits v ON h.id = v.place_id";
+    visitOrderFragment = "ORDER BY v.visit_date DESC";
+  }
+
+  let pageMetaSelectionFragment = "";
+  if (options.includeMeta) {
+    pageMetaSelectionFragment = ", description, site_name, preview_image_url";
+  }
+
+  let query = `SELECT h.id, guid, url, title, frecency
+               ${pageMetaSelectionFragment} ${visitSelectionFragment}
+               FROM moz_places h ${joinFragment}
+               ${whereClauseFragment}
+               ${visitOrderFragment}`;
+  let pageInfo = null;
+  let placeId = null;
+  await db.executeCached(query, params, row => {
+    if (pageInfo === null) {
+      // This means we're on the first row, so we need to get all the page info.
+      pageInfo = {
+        guid: row.getResultByName("guid"),
+        url: new URL(row.getResultByName("url")),
+        frecency: row.getResultByName("frecency"),
+        title: row.getResultByName("title") || "",
+      };
+      placeId = row.getResultByName("id");
+    }
+    if (options.includeMeta) {
+      pageInfo.description = row.getResultByName("description") || "";
+      pageInfo.siteName = row.getResultByName("site_name") || "";
+      let previewImageURL = row.getResultByName("preview_image_url");
+      pageInfo.previewImageURL = previewImageURL
+        ? new URL(previewImageURL)
+        : null;
+    }
+    if (options.includeVisits) {
+      // On every row (not just the first), we need to collect visit data.
+      if (!("visits" in pageInfo)) {
+        pageInfo.visits = [];
+      }
+      let date = lazy.PlacesUtils.toDate(row.getResultByName("visit_date"));
+      let transition = row.getResultByName("visit_type");
+
+      // TODO: Bug #1365913 add referrer URL to the `VisitInfo` data as well.
+      pageInfo.visits.push({ date, transition });
+    }
+  });
+
+  // Only try to get annotations if requested, and if there's an actual page found.
+  if (pageInfo && options.includeAnnotations) {
+    let rows = await db.executeCached(
+      `
+      SELECT n.name, a.content FROM moz_anno_attributes n
+      JOIN moz_annos a ON n.id = a.anno_attribute_id
+      WHERE a.place_id = :placeId
+    `,
+      { placeId }
+    );
+
+    pageInfo.annotations = new Map(
+      rows.map(row => [
+        row.getResultByName("name"),
+        row.getResultByName("content"),
+      ])
+    );
+  }
+  return pageInfo;
+};
+
+// Inner implementation of History.fetchAnnotatedPages.
+var fetchAnnotatedPages = async function (db, annotations) {
+  let result = new Map();
+  let rows = await db.execute(
+    `
+    SELECT n.name, h.url, a.content FROM moz_anno_attributes n
+    JOIN moz_annos a ON n.id = a.anno_attribute_id
+    JOIN moz_places h ON h.id = a.place_id
+    WHERE n.name IN (${new Array(annotations.length).fill("?").join(",")})
+  `,
+    annotations
+  );
+
+  for (let row of rows) {
+    let uri;
+    try {
+      uri = new URL(row.getResultByName("url"));
+    } catch (ex) {
+      console.error("Invalid URL read from database in fetchAnnotatedPages");
+      continue;
+    }
+
+    let anno = {
+      uri,
+      content: row.getResultByName("content"),
+    };
+    let annoName = row.getResultByName("name");
+    let pageAnnos = result.get(annoName);
+    if (!pageAnnos) {
+      pageAnnos = [];
+      result.set(annoName, pageAnnos);
+    }
+    pageAnnos.push(anno);
+  }
+
+  return result;
+};
+
+// Inner implementation of History.fetchMany.
+var fetchMany = async function (db, guidOrURLs) {
+  let resultsMap = new Map();
+  for (let chunk of lazy.PlacesUtils.chunkArray(guidOrURLs, db.variableLimit)) {
+    let urls = [];
+    let guids = [];
+    for (let v of chunk) {
+      if (URL.isInstance(v)) {
+        urls.push(v);
+      } else {
+        guids.push(v);
+      }
+    }
+    let wheres = [];
+    let params = [];
+    if (urls.length) {
+      wheres.push(`
+        (
+          url_hash IN(${lazy.PlacesUtils.sqlBindPlaceholders(
+            urls,
+            "hash(",
+            ")"
+          )}) AND
+          url IN(${lazy.PlacesUtils.sqlBindPlaceholders(urls)})
+        )`);
+      let hrefs = urls.map(u => u.href);
+      params = [...params, ...hrefs, ...hrefs];
+    }
+    if (guids.length) {
+      wheres.push(`guid IN(${lazy.PlacesUtils.sqlBindPlaceholders(guids)})`);
+      params = [...params, ...guids];
+    }
+
+    let rows = await db.executeCached(
+      `
+      SELECT h.id, guid, url, title, frecency
+      FROM moz_places h
+      WHERE ${wheres.join(" OR ")}
+    `,
+      params
+    );
+    for (let row of rows) {
+      let pageInfo = {
+        guid: row.getResultByName("guid"),
+        url: new URL(row.getResultByName("url")),
+        frecency: row.getResultByName("frecency"),
+        title: row.getResultByName("title") || "",
+      };
+      if (guidOrURLs.includes(pageInfo.guid)) {
+        resultsMap.set(pageInfo.guid, pageInfo);
+      } else {
+        resultsMap.set(pageInfo.url.href, pageInfo);
+      }
+    }
+  }
+  return resultsMap;
+};
+
+// Inner implementation of History.removeVisitsByFilter.
+var removeVisitsByFilter = async function (db, filter, onResult = null) {
+  // 1. Determine visits that took place during the interval.  Note
+  // that the database uses microseconds, while JS uses milliseconds,
+  // so we need to *1000 one way and /1000 the other way.
+  let conditions = [];
+  let args = {};
+  let transition = -1;
+  if ("beginDate" in filter) {
+    conditions.push("v.visit_date >= :begin * 1000");
+    args.begin = Number(filter.beginDate);
+  }
+  if ("endDate" in filter) {
+    conditions.push("v.visit_date <= :end * 1000");
+    args.end = Number(filter.endDate);
+  }
+  if ("limit" in filter) {
+    args.limit = Number(filter.limit);
+  }
+  if ("transition" in filter) {
+    conditions.push("v.visit_type = :transition");
+    args.transition = filter.transition;
+    transition = filter.transition;
+  }
+
+  let optionalJoin = "";
+  if ("url" in filter) {
+    let url = filter.url;
+    if (url instanceof Ci.nsIURI) {
+      url = filter.url.spec;
+    } else {
+      url = new URL(url).href;
+    }
+    optionalJoin = `JOIN moz_places h ON h.id = v.place_id`;
+    conditions.push("h.url_hash = hash(:url)", "h.url = :url");
+    args.url = url;
+  }
+
+  let visitsToRemove = [];
+  let pagesToInspect = new Set();
+  let onResultData = onResult ? [] : null;
+
+  await db.executeCached(
+    `SELECT v.id, place_id, visit_date / 1000 AS date, visit_type FROM moz_historyvisits v
+             ${optionalJoin}
+             WHERE ${conditions.join(" AND ")}${
+      args.limit ? " LIMIT :limit" : ""
+    }`,
+    args,
+    row => {
+      let id = row.getResultByName("id");
+      let place_id = row.getResultByName("place_id");
+      visitsToRemove.push(id);
+      pagesToInspect.add(place_id);
+
+      if (onResult) {
+        onResultData.push({
+          date: new Date(row.getResultByName("date")),
+          transition: row.getResultByName("visit_type"),
+        });
+      }
+    }
+  );
+
+  if (!visitsToRemove.length) {
+    // Nothing to do
+    return false;
+  }
+
+  let pages = [];
+  await db.executeTransaction(async function () {
+    // 2. Remove all offending visits.
+    for (let chunk of lazy.PlacesUtils.chunkArray(
+      visitsToRemove,
+      db.variableLimit
+    )) {
+      await db.execute(
+        `DELETE FROM moz_historyvisits
+         WHERE id IN (${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+        chunk
+      );
+    }
+
+    // 3. Find out which pages have been orphaned
+    for (let chunk of lazy.PlacesUtils.chunkArray(
+      [...pagesToInspect],
+      db.variableLimit
+    )) {
+      await db.execute(
+        `SELECT id, url, url_hash, guid,
+          (foreign_count != 0) AS has_foreign,
+          (last_visit_date NOTNULL) as has_visits
+         FROM moz_places
+         WHERE id IN (${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+        chunk,
+        row => {
+          let page = {
+            id: row.getResultByName("id"),
+            guid: row.getResultByName("guid"),
+            hasForeign: row.getResultByName("has_foreign"),
+            hasVisits: row.getResultByName("has_visits"),
+            url: new URL(row.getResultByName("url")),
+            hash: row.getResultByName("url_hash"),
+          };
+          pages.push(page);
+        }
+      );
+    }
+
+    // 4. Clean up and notify
+    await cleanupPages(db, pages);
+  });
+
+  notifyCleanup(db, pages, transition);
+  notifyOnResult(onResultData, onResult); // don't wait
+
+  return !!visitsToRemove.length;
+};
+
+// Inner implementation of History.removeByFilter
+var removeByFilter = async function (db, filter, onResult = null) {
+  // 1. Create fragment for date filtration
+  let dateFilterSQLFragment = "";
+  let conditions = [];
+  let params = {};
+  if ("beginDate" in filter) {
+    conditions.push("v.visit_date >= :begin");
+    params.begin = lazy.PlacesUtils.toPRTime(filter.beginDate);
+  }
+  if ("endDate" in filter) {
+    conditions.push("v.visit_date <= :end");
+    params.end = lazy.PlacesUtils.toPRTime(filter.endDate);
+  }
+
+  if (conditions.length !== 0) {
+    dateFilterSQLFragment = `EXISTS
+         (SELECT id FROM moz_historyvisits v WHERE v.place_id = h.id AND
+         ${conditions.join(" AND ")}
+         LIMIT 1)`;
+  }
+
+  // 2. Create fragment for host and subhost filtering
+  let hostFilterSQLFragment = "";
+  if (filter.host) {
+    // There are four cases that we need to consider:
+    // mozilla.org, .mozilla.org, localhost, and local files
+    let revHost = filter.host.split("").reverse().join("");
+    if (filter.host == ".") {
+      // Local files.
+      hostFilterSQLFragment = `h.rev_host = :revHost`;
+    } else if (filter.host.startsWith(".")) {
+      // Remove the subhost wildcard.
+      revHost = revHost.slice(0, -1);
+      hostFilterSQLFragment = `h.rev_host between :revHost || "." and :revHost || "/"`;
+    } else {
+      // This covers non-wildcarded hosts (e.g.: mozilla.org, localhost)
+      hostFilterSQLFragment = `h.rev_host = :revHost || "."`;
+    }
+    params.revHost = revHost;
+  }
+
+  // 3. Find out what needs to be removed
+  let fragmentArray = [hostFilterSQLFragment, dateFilterSQLFragment];
+  let query = `SELECT h.id, url, url_hash, rev_host, guid, title, frecency, foreign_count
+       FROM moz_places h WHERE
+       (${fragmentArray.filter(f => f !== "").join(") AND (")})`;
+  let onResultData = onResult ? [] : null;
+  let pages = [];
+  let hasPagesToRemove = false;
+
+  await db.executeCached(query, params, row => {
+    let hasForeign = row.getResultByName("foreign_count") != 0;
+    if (!hasForeign) {
+      hasPagesToRemove = true;
+    }
+    let id = row.getResultByName("id");
+    let guid = row.getResultByName("guid");
+    let url = row.getResultByName("url");
+    let page = {
+      id,
+      guid,
+      hasForeign,
+      hasVisits: false,
+      url: new URL(url),
+      hash: row.getResultByName("url_hash"),
+    };
+    pages.push(page);
+    if (onResult) {
+      onResultData.push({
+        guid,
+        title: row.getResultByName("title"),
+        frecency: row.getResultByName("frecency"),
+        url: new URL(url),
+      });
+    }
+  });
+
+  if (pages.length === 0) {
+    // Nothing to do
+    return false;
+  }
+
+  await db.executeTransaction(async function () {
+    // 4. Actually remove visits
+    let pageIds = pages.map(p => p.id);
+    for (let chunk of lazy.PlacesUtils.chunkArray(pageIds, db.variableLimit)) {
+      await db.execute(
+        `DELETE FROM moz_historyvisits
+         WHERE place_id IN(${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+        chunk
+      );
+    }
+    // 5. Clean up and notify
+    await cleanupPages(db, pages);
+  });
+
+  notifyCleanup(db, pages);
+  notifyOnResult(onResultData, onResult);
+
+  return hasPagesToRemove;
+};
+
+// Inner implementation of History.remove.
+var remove = async function (db, { guids, urls }, onResult = null) {
+  // 1. Find out what needs to be removed
+  let onResultData = onResult ? [] : null;
+  let pages = [];
+  let hasPagesToRemove = false;
+  function onRow(row) {
+    let hasForeign = row.getResultByName("foreign_count") != 0;
+    if (!hasForeign) {
+      hasPagesToRemove = true;
+    }
+    let id = row.getResultByName("id");
+    let guid = row.getResultByName("guid");
+    let url = row.getResultByName("url");
+    let page = {
+      id,
+      guid,
+      hasForeign,
+      hasVisits: false,
+      url: new URL(url),
+      hash: row.getResultByName("url_hash"),
+    };
+    pages.push(page);
+    if (onResult) {
+      onResultData.push({
+        guid,
+        title: row.getResultByName("title"),
+        frecency: row.getResultByName("frecency"),
+        url: new URL(url),
+      });
+    }
+  }
+  for (let chunk of lazy.PlacesUtils.chunkArray(guids, db.variableLimit)) {
+    let query = `SELECT id, url, url_hash, guid, foreign_count, title, frecency
+       FROM moz_places
+       WHERE guid IN (${lazy.PlacesUtils.sqlBindPlaceholders(guids)})
+      `;
+    await db.execute(query, chunk, onRow);
+  }
+  for (let chunk of lazy.PlacesUtils.chunkArray(urls, db.variableLimit)) {
+    // Make an array of variables like `["?1", "?2", ...]`, up to the length of
+    // the chunk. This lets us bind each URL once, reusing the binding for the
+    // `url_hash IN (...)` and `url IN (...)` clauses. We add 1 because indexed
+    // parameters start at 1, not 0.
+    let variables = Array.from(
+      { length: chunk.length },
+      (_, i) => "?" + (i + 1)
+    );
+    let query = `SELECT id, url, url_hash, guid, foreign_count, title, frecency
+       FROM moz_places
+       WHERE url_hash IN (${variables.map(v => `hash(${v})`).join(",")}) AND
+             url IN (${variables.join(",")})
+      `;
+    await db.execute(query, chunk, onRow);
+  }
+
+  if (!pages.length) {
+    // Nothing to do
+    return false;
+  }
+
+  await db.executeTransaction(async function () {
+    // 2. Remove all visits to these pages.
+    let pageIds = pages.map(p => p.id);
+    for (let chunk of lazy.PlacesUtils.chunkArray(pageIds, db.variableLimit)) {
+      await db.execute(
+        `DELETE FROM moz_historyvisits
+         WHERE place_id IN (${lazy.PlacesUtils.sqlBindPlaceholders(chunk)})`,
+        chunk
+      );
+    }
+
+    // 3. Clean up and notify
+    await cleanupPages(db, pages);
+  });
+
+  notifyCleanup(db, pages);
+  notifyOnResult(onResultData, onResult); // don't wait
+
+  return hasPagesToRemove;
+};
+
+/**
+ * Merges an updateInfo object, as returned by asyncHistory.updatePlaces
+ * into a PageInfo object as defined in this file.
+ *
+ * @param updateInfo: (Object)
+ *      An object that represents a page that is generated by
+ *      asyncHistory.updatePlaces.
+ * @param pageInfo: (PageInfo)
+ *      An PageInfo object into which to merge the data from updateInfo.
+ *      Defaults to an empty object so that this method can be used
+ *      to simply convert an updateInfo object into a PageInfo object.
+ *
+ * @return (PageInfo)
+ *      A PageInfo object populated with data from updateInfo.
+ */
+function mergeUpdateInfoIntoPageInfo(updateInfo, pageInfo = {}) {
+  pageInfo.guid = updateInfo.guid;
+  pageInfo.title = updateInfo.title;
+  if (!pageInfo.url) {
+    pageInfo.url = URL.fromURI(updateInfo.uri);
+    pageInfo.title = updateInfo.title;
+    pageInfo.placeId = updateInfo.placeId;
+    pageInfo.visits = updateInfo.visits.map(visit => {
+      return {
+        visitId: visit.visitId,
+        date: lazy.PlacesUtils.toDate(visit.visitDate),
+        transition: visit.transitionType,
+        referrer: visit.referrerURI ? URL.fromURI(visit.referrerURI) : null,
+      };
+    });
+  }
+  return pageInfo;
+}
+
+// Inner implementation of History.insert.
+var insert = function (db, pageInfo) {
+  let info = convertForUpdatePlaces(pageInfo);
+
+  return new Promise((resolve, reject) => {
+    lazy.asyncHistory.updatePlaces(info, {
+      handleError: error => {
+        reject(error);
+      },
+      handleResult: result => {
+        pageInfo = mergeUpdateInfoIntoPageInfo(result, pageInfo);
+      },
+      handleCompletion: () => {
+        resolve(pageInfo);
+      },
+    });
+  });
+};
+
+// Inner implementation of History.insertMany.
+var insertMany = function (db, pageInfos, onResult, onError) {
+  let infos = [];
+  let onResultData = [];
+  let onErrorData = [];
+
+  for (let pageInfo of pageInfos) {
+    let info = convertForUpdatePlaces(pageInfo);
+    infos.push(info);
+  }
+
+  return new Promise((resolve, reject) => {
+    lazy.asyncHistory.updatePlaces(infos, {
+      handleError: (resultCode, result) => {
+        let pageInfo = mergeUpdateInfoIntoPageInfo(result);
+        onErrorData.push(pageInfo);
+      },
+      handleResult: result => {
+        let pageInfo = mergeUpdateInfoIntoPageInfo(result);
+        onResultData.push(pageInfo);
+      },
+      ignoreErrors: !onError,
+      ignoreResults: !onResult,
+      handleCompletion: updatedCount => {
+        notifyOnResult(onResultData, onResult);
+        notifyOnResult(onErrorData, onError);
+        if (updatedCount > 0) {
+          resolve();
+        } else {
+          reject({ message: "No items were added to history." });
+        }
+      },
+    });
+  });
+};
+
+// Inner implementation of History.update.
+var update = async function (db, pageInfo) {
+  // Check for page existence first; we can skip most of the work if it doesn't
+  // exist and anyway we'll need the place id multiple times later.
+  // Prefer GUID over url if it's present.
+  let id;
+  if (typeof pageInfo.guid === "string") {
+    let rows = await db.executeCached(
+      "SELECT id FROM moz_places WHERE guid = :guid",
+      { guid: pageInfo.guid }
+    );
+    id = rows.length ? rows[0].getResultByName("id") : null;
+  } else {
+    let rows = await db.executeCached(
+      "SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url",
+      { url: pageInfo.url.href }
+    );
+    id = rows.length ? rows[0].getResultByName("id") : null;
+  }
+  if (!id) {
+    return;
+  }
+
+  let updateFragments = [];
+  let params = {};
+  if ("description" in pageInfo) {
+    updateFragments.push("description");
+    params.description = pageInfo.description;
+  }
+  if ("siteName" in pageInfo) {
+    updateFragments.push("site_name");
+    params.site_name = pageInfo.siteName;
+  }
+  if ("previewImageURL" in pageInfo) {
+    updateFragments.push("preview_image_url");
+    params.preview_image_url = pageInfo.previewImageURL
+      ? pageInfo.previewImageURL.href
+      : null;
+  }
+  if (updateFragments.length) {
+    // Since this data may be written at every visit and is textual, avoid
+    // overwriting the existing record if it didn't change.
+    await db.execute(
+      `
+      UPDATE moz_places
+      SET ${updateFragments.map(v => `${v} = :${v}`).join(", ")}
+      WHERE id = :id
+        AND (${updateFragments
+          .map(v => `IFNULL(${v}, '') <> IFNULL(:${v}, '')`)
+          .join(" OR ")})
+    `,
+      { id, ...params }
+    );
+  }
+
+  if (pageInfo.annotations) {
+    let annosToRemove = [];
+    let annosToUpdate = [];
+
+    for (let anno of pageInfo.annotations) {
+      anno[1] ? annosToUpdate.push(anno[0]) : annosToRemove.push(anno[0]);
+    }
+
+    await db.executeTransaction(async function () {
+      if (annosToUpdate.length) {
+        await db.execute(
+          `
+          INSERT OR IGNORE INTO moz_anno_attributes (name)
+          VALUES ${Array.from(annosToUpdate.keys())
+            .map(k => `(:${k})`)
+            .join(", ")}
+        `,
+          Object.assign({}, annosToUpdate)
+        );
+
+        for (let anno of annosToUpdate) {
+          let content = pageInfo.annotations.get(anno);
+          // TODO: We only really need to save the type whilst we still support
+          // accessing page annotations via the annotation service.
+          let type =
+            typeof content == "string"
+              ? History.ANNOTATION_TYPE_STRING
+              : History.ANNOTATION_TYPE_INT64;
+          let date = lazy.PlacesUtils.toPRTime(new Date());
+
+          // This will replace the id every time an annotation is updated. This is
+          // not currently an issue as we're not joining on the id field.
+          await db.execute(
+            `
+            INSERT OR REPLACE INTO moz_annos
+              (place_id, anno_attribute_id, content, flags,
+               expiration, type, dateAdded, lastModified)
+            VALUES (:id,
+                    (SELECT id FROM moz_anno_attributes WHERE name = :anno_name),
+                    :content, 0, :expiration, :type, :date_added,
+                    :last_modified)
+          `,
+            {
+              id,
+              anno_name: anno,
+              content,
+              expiration: History.ANNOTATION_EXPIRE_NEVER,
+              type,
+              // The date fields are unused, so we just set them both to the latest.
+              date_added: date,
+              last_modified: date,
+            }
+          );
+        }
+      }
+
+      for (let anno of annosToRemove) {
+        // We don't remove anything from the moz_anno_attributes table. If we
+        // delete the last item of a given name, that item really should go away.
+        // It will be cleaned up by expiration.
+        await db.execute(
+          `
+          DELETE FROM moz_annos
+          WHERE place_id = :id
+          AND anno_attribute_id =
+            (SELECT id FROM moz_anno_attributes WHERE name = :anno_name)
+        `,
+          { id, anno_name: anno }
+        );
+      }
+    });
+  }
+};
diff --git a/toolkit/components/places/INativePlacesEventCallback.h b/toolkit/components/places/INativePlacesEventCallback.h
new file mode 100644
index 0000000000..46e52146e2
--- /dev/null
+++ b/toolkit/components/places/INativePlacesEventCallback.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_image_INativePlacesEventCallback_h
+#define mozilla_image_INativePlacesEventCallback_h
+
+#include "mozilla/dom/PlacesObserversBinding.h"
+#include "mozilla/WeakPtr.h"
+#include "nsISupports.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace places {
+
+class INativePlacesEventCallback : public SupportsWeakPtr {
+ public:
+  typedef dom::Sequence<OwningNonNull<dom::PlacesEvent>> PlacesEventSequence;
+
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  virtual void HandlePlacesEvent(const PlacesEventSequence& aEvents) = 0;
+
+ protected:
+  virtual ~INativePlacesEventCallback() = default;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_image_INativePlacesEventCallback_h
diff --git a/toolkit/components/places/NotifyRankingChanged.h b/toolkit/components/places/NotifyRankingChanged.h
new file mode 100644
index 0000000000..e902fe8016
--- /dev/null
+++ b/toolkit/components/places/NotifyRankingChanged.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_NotifyRankingChanged_h_
+#define mozilla_places_NotifyRankingChanged_h_
+
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/dom/PlacesRanking.h"
+
+using namespace mozilla::dom;
+
+namespace mozilla {
+namespace places {
+
+class NotifyRankingChanged final : public Runnable {
+ public:
+  NotifyRankingChanged() : Runnable("places::NotifyRankingChanged") {}
+
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY until Runnable::Run is marked
+  // MOZ_CAN_RUN_SCRIPT.  See bug 1535398.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread(), "This should be called on the main thread");
+
+    RefPtr<PlacesRanking> event = new PlacesRanking();
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    bool success = !!events.AppendElement(event.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+    PlacesObservers::NotifyListeners(events);
+
+    return NS_OK;
+  }
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_NotifyRankingChanged_h_
diff --git a/toolkit/components/places/PageIconProtocolHandler.cpp b/toolkit/components/places/PageIconProtocolHandler.cpp
new file mode 100644
index 0000000000..a2f1d60edd
--- /dev/null
+++ b/toolkit/components/places/PageIconProtocolHandler.cpp
@@ -0,0 +1,397 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PageIconProtocolHandler.h"
+
+#include "mozilla/NullPrincipal.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Components.h"
+#include "mozilla/Try.h"
+#include "nsFaviconService.h"
+#include "nsStringStream.h"
+#include "nsStreamUtils.h"
+#include "nsIChannel.h"
+#include "nsIFaviconService.h"
+#include "nsIIOService.h"
+#include "nsILoadInfo.h"
+#include "nsIOutputStream.h"
+#include "nsIPipe.h"
+#include "nsIRequestObserver.h"
+#include "nsIURIMutator.h"
+#include "nsNetUtil.h"
+#include "SimpleChannel.h"
+
+#define PAGE_ICON_SCHEME "page-icon"
+
+using mozilla::net::IsNeckoChild;
+using mozilla::net::NeckoChild;
+using mozilla::net::RemoteStreamGetter;
+using mozilla::net::RemoteStreamInfo;
+
+namespace mozilla::places {
+
+struct FaviconMetadata {
+  nsCOMPtr<nsIInputStream> mStream;
+  nsCString mContentType;
+  int64_t mContentLength = 0;
+};
+
+StaticRefPtr<PageIconProtocolHandler> PageIconProtocolHandler::sSingleton;
+
+namespace {
+
+class DefaultFaviconObserver final : public nsIRequestObserver {
+ public:
+  explicit DefaultFaviconObserver(nsIOutputStream* aOutputStream)
+      : mOutputStream(aOutputStream) {
+    MOZ_ASSERT(aOutputStream);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIREQUESTOBSERVER
+ private:
+  ~DefaultFaviconObserver() = default;
+
+  nsCOMPtr<nsIOutputStream> mOutputStream;
+};
+
+NS_IMPL_ISUPPORTS(DefaultFaviconObserver, nsIRequestObserver);
+
+NS_IMETHODIMP DefaultFaviconObserver::OnStartRequest(nsIRequest*) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP DefaultFaviconObserver::OnStopRequest(nsIRequest*, nsresult) {
+  // We must close the outputStream regardless.
+  mOutputStream->Close();
+  return NS_OK;
+}
+
+}  // namespace
+
+static nsresult MakeDefaultFaviconChannel(nsIURI* aURI, nsILoadInfo* aLoadInfo,
+                                          nsIChannel** aOutChannel) {
+  nsCOMPtr<nsIIOService> ios = mozilla::components::IO::Service();
+  nsCOMPtr<nsIChannel> chan;
+  nsCOMPtr<nsIURI> defaultFaviconURI;
+
+  auto* faviconService = nsFaviconService::GetFaviconService();
+  if (MOZ_UNLIKELY(!faviconService)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult rv =
+      faviconService->GetDefaultFavicon(getter_AddRefs(defaultFaviconURI));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = ios->NewChannelFromURIWithLoadInfo(defaultFaviconURI, aLoadInfo,
+                                          getter_AddRefs(chan));
+  NS_ENSURE_SUCCESS(rv, rv);
+  chan->SetOriginalURI(aURI);
+  chan->SetContentType(nsLiteralCString(FAVICON_DEFAULT_MIMETYPE));
+  chan.forget(aOutChannel);
+  return NS_OK;
+}
+
+static nsresult StreamDefaultFavicon(nsIURI* aURI, nsILoadInfo* aLoadInfo,
+                                     nsIOutputStream* aOutputStream) {
+  auto closeStreamOnError =
+      mozilla::MakeScopeExit([&] { aOutputStream->Close(); });
+
+  auto observer = MakeRefPtr<DefaultFaviconObserver>(aOutputStream);
+
+  nsCOMPtr<nsIStreamListener> listener;
+  nsresult rv = NS_NewSimpleStreamListener(getter_AddRefs(listener),
+                                           aOutputStream, observer);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIChannel> defaultIconChannel;
+  rv = MakeDefaultFaviconChannel(aURI, aLoadInfo,
+                                 getter_AddRefs(defaultIconChannel));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = defaultIconChannel->AsyncOpen(listener);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  closeStreamOnError.release();
+  return NS_OK;
+}
+
+namespace {
+
+class FaviconDataCallback final : public nsIFaviconDataCallback {
+ public:
+  FaviconDataCallback(nsIURI* aURI, nsILoadInfo* aLoadInfo)
+      : mURI(aURI), mLoadInfo(aLoadInfo) {
+    MOZ_ASSERT(aURI);
+    MOZ_ASSERT(aLoadInfo);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIFAVICONDATACALLBACK
+
+  RefPtr<FaviconMetadataPromise> Promise() {
+    return mPromiseHolder.Ensure(__func__);
+  }
+
+ private:
+  ~FaviconDataCallback();
+  nsCOMPtr<nsIURI> mURI;
+  MozPromiseHolder<FaviconMetadataPromise> mPromiseHolder;
+  nsCOMPtr<nsILoadInfo> mLoadInfo;
+};
+
+NS_IMPL_ISUPPORTS(FaviconDataCallback, nsIFaviconDataCallback);
+
+FaviconDataCallback::~FaviconDataCallback() {
+  mPromiseHolder.RejectIfExists(NS_ERROR_FAILURE, __func__);
+}
+
+NS_IMETHODIMP FaviconDataCallback::OnComplete(nsIURI* aURI, uint32_t aDataLen,
+                                              const uint8_t* aData,
+                                              const nsACString& aMimeType,
+                                              uint16_t aWidth) {
+  if (!aDataLen) {
+    mPromiseHolder.Reject(NS_ERROR_NOT_AVAILABLE, __func__);
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIInputStream> inputStream;
+  nsresult rv =
+      NS_NewByteInputStream(getter_AddRefs(inputStream),
+                            AsChars(Span{aData, aDataLen}), NS_ASSIGNMENT_COPY);
+  if (NS_FAILED(rv)) {
+    mPromiseHolder.Reject(rv, __func__);
+    return rv;
+  }
+
+  FaviconMetadata metadata;
+  metadata.mStream = inputStream;
+  metadata.mContentType = aMimeType;
+  metadata.mContentLength = aDataLen;
+  mPromiseHolder.Resolve(std::move(metadata), __func__);
+
+  return NS_OK;
+}
+
+}  // namespace
+
+NS_IMPL_ISUPPORTS(PageIconProtocolHandler, nsIProtocolHandler,
+                  nsISupportsWeakReference);
+
+NS_IMETHODIMP PageIconProtocolHandler::GetScheme(nsACString& aScheme) {
+  aScheme.AssignLiteral(PAGE_ICON_SCHEME);
+  return NS_OK;
+}
+
+NS_IMETHODIMP PageIconProtocolHandler::AllowPort(int32_t, const char*,
+                                                 bool* aAllow) {
+  *aAllow = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP PageIconProtocolHandler::NewChannel(nsIURI* aURI,
+                                                  nsILoadInfo* aLoadInfo,
+                                                  nsIChannel** aOutChannel) {
+  // Load the URI remotely if accessed from a child.
+  if (IsNeckoChild()) {
+    MOZ_TRY(SubstituteRemoteChannel(aURI, aLoadInfo, aOutChannel));
+    return NS_OK;
+  }
+
+  nsresult rv = NewChannelInternal(aURI, aLoadInfo, aOutChannel);
+  if (NS_SUCCEEDED(rv)) {
+    return rv;
+  }
+  return MakeDefaultFaviconChannel(aURI, aLoadInfo, aOutChannel);
+}
+
+Result<Ok, nsresult> PageIconProtocolHandler::SubstituteRemoteChannel(
+    nsIURI* aURI, nsILoadInfo* aLoadInfo, nsIChannel** aRetVal) {
+  MOZ_ASSERT(IsNeckoChild());
+  MOZ_TRY(aURI ? NS_OK : NS_ERROR_INVALID_ARG);
+  MOZ_TRY(aLoadInfo ? NS_OK : NS_ERROR_INVALID_ARG);
+
+  RefPtr<RemoteStreamGetter> streamGetter =
+      new RemoteStreamGetter(aURI, aLoadInfo);
+
+  NewSimpleChannel(aURI, aLoadInfo, streamGetter, aRetVal);
+  return Ok();
+}
+
+nsresult PageIconProtocolHandler::NewChannelInternal(nsIURI* aURI,
+                                                     nsILoadInfo* aLoadInfo,
+                                                     nsIChannel** aOutChannel) {
+  // Create a pipe that will give us an output stream that we can use once
+  // we got all the favicon data.
+  nsCOMPtr<nsIAsyncInputStream> pipeIn;
+  nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+  GetStreams(getter_AddRefs(pipeIn), getter_AddRefs(pipeOut));
+
+  // Create our channel.
+  nsCOMPtr<nsIChannel> channel;
+  {
+    // We override the channel's loadinfo below anyway, so using a null
+    // principal here is alright.
+    nsCOMPtr<nsIPrincipal> loadingPrincipal =
+        NullPrincipal::CreateWithoutOriginAttributes();
+    nsresult rv = NS_NewInputStreamChannel(
+        getter_AddRefs(channel), aURI, pipeIn.forget(), loadingPrincipal,
+        nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_IS_BLOCKED,
+        nsIContentPolicy::TYPE_INTERNAL_IMAGE);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsresult rv = channel->SetLoadInfo(aLoadInfo);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  GetFaviconData(aURI, aLoadInfo)
+      ->Then(
+          GetMainThreadSerialEventTarget(), __func__,
+          [pipeOut, channel](const FaviconMetadata& aMetadata) {
+            channel->SetContentType(aMetadata.mContentType);
+            channel->SetContentLength(aMetadata.mContentLength);
+
+            nsresult rv;
+            const nsCOMPtr<nsIEventTarget> target =
+                do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID, &rv);
+
+            if (NS_WARN_IF(NS_FAILED(rv))) {
+              channel->CancelWithReason(NS_BINDING_ABORTED,
+                                        "GetFaviconData failed"_ns);
+              return;
+            }
+
+            NS_AsyncCopy(aMetadata.mStream, pipeOut, target);
+          },
+          [uri = nsCOMPtr{aURI}, loadInfo = nsCOMPtr{aLoadInfo}, pipeOut,
+           channel](nsresult aRv) {
+            // There are a few reasons why this might fail. For example, one
+            // reason is that the URI might not actually be properly parsable.
+            // In that case, we'll try one last time to stream the default
+            // favicon before giving up.
+            channel->SetContentType(nsLiteralCString(FAVICON_DEFAULT_MIMETYPE));
+            channel->SetContentLength(-1);
+            Unused << StreamDefaultFavicon(uri, loadInfo, pipeOut);
+          });
+  channel.forget(aOutChannel);
+  return NS_OK;
+}
+
+RefPtr<FaviconMetadataPromise> PageIconProtocolHandler::GetFaviconData(
+    nsIURI* aPageIconURI, nsILoadInfo* aLoadInfo) {
+  auto* faviconService = nsFaviconService::GetFaviconService();
+  if (MOZ_UNLIKELY(!faviconService)) {
+    return FaviconMetadataPromise::CreateAndReject(NS_ERROR_UNEXPECTED,
+                                                   __func__);
+  }
+
+  uint16_t preferredSize = 0;
+  faviconService->PreferredSizeFromURI(aPageIconURI, &preferredSize);
+
+  nsCOMPtr<nsIURI> pageURI;
+  nsresult rv;
+  {
+    // NOTE: We don't need to strip #size= fragments because
+    // GetFaviconDataForPage strips them when doing the database lookup.
+    nsAutoCString pageQuery;
+    aPageIconURI->GetPathQueryRef(pageQuery);
+    rv = NS_NewURI(getter_AddRefs(pageURI), pageQuery);
+    if (NS_FAILED(rv)) {
+      return FaviconMetadataPromise::CreateAndReject(rv, __func__);
+    }
+  }
+
+  auto faviconCallback =
+      MakeRefPtr<FaviconDataCallback>(aPageIconURI, aLoadInfo);
+  rv = faviconService->GetFaviconDataForPage(pageURI, faviconCallback,
+                                             preferredSize);
+  if (NS_FAILED(rv)) {
+    return FaviconMetadataPromise::CreateAndReject(rv, __func__);
+  }
+
+  return faviconCallback->Promise();
+}
+
+RefPtr<RemoteStreamPromise> PageIconProtocolHandler::NewStream(
+    nsIURI* aChildURI, nsILoadInfo* aLoadInfo, bool* aTerminateSender) {
+  MOZ_ASSERT(!IsNeckoChild());
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!aChildURI || !aLoadInfo || !aTerminateSender) {
+    return RemoteStreamPromise::CreateAndReject(NS_ERROR_INVALID_ARG, __func__);
+  }
+
+  *aTerminateSender = true;
+
+  // We should never receive a URI that isn't for a page-icon because
+  // these requests ordinarily come from the child's PageIconProtocolHandler.
+  // Ensure this request is for a page-icon URI. A compromised child process
+  // could send us any URI.
+  bool isPageIconScheme = false;
+  if (NS_FAILED(aChildURI->SchemeIs(PAGE_ICON_SCHEME, &isPageIconScheme)) ||
+      !isPageIconScheme) {
+    return RemoteStreamPromise::CreateAndReject(NS_ERROR_UNKNOWN_PROTOCOL,
+                                                __func__);
+  }
+
+  // For errors after this point, we want to propagate the error to
+  // the child, but we don't force the child process to be terminated.
+  *aTerminateSender = false;
+
+  RefPtr<RemoteStreamPromise::Private> outerPromise =
+      new RemoteStreamPromise::Private(__func__);
+  nsCOMPtr<nsIURI> uri(aChildURI);
+  nsCOMPtr<nsILoadInfo> loadInfo(aLoadInfo);
+  RefPtr<PageIconProtocolHandler> self = this;
+
+  GetFaviconData(uri, loadInfo)
+      ->Then(
+          GetMainThreadSerialEventTarget(), __func__,
+          [outerPromise](const FaviconMetadata& aMetadata) {
+            RemoteStreamInfo info(aMetadata.mStream, aMetadata.mContentType,
+                                  aMetadata.mContentLength);
+            outerPromise->Resolve(std::move(info), __func__);
+          },
+          [self, uri, loadInfo, outerPromise](nsresult aRv) {
+            nsCOMPtr<nsIAsyncInputStream> pipeIn;
+            nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+            self->GetStreams(getter_AddRefs(pipeIn), getter_AddRefs(pipeOut));
+
+            RemoteStreamInfo info(
+                pipeIn, nsLiteralCString(FAVICON_DEFAULT_MIMETYPE), -1);
+            Unused << StreamDefaultFavicon(uri, loadInfo, pipeOut);
+            outerPromise->Resolve(std::move(info), __func__);
+          });
+  return outerPromise;
+}
+
+void PageIconProtocolHandler::GetStreams(nsIAsyncInputStream** inStream,
+                                         nsIAsyncOutputStream** outStream) {
+  static constexpr size_t kSegmentSize = 4096;
+  nsCOMPtr<nsIAsyncInputStream> pipeIn;
+  nsCOMPtr<nsIAsyncOutputStream> pipeOut;
+  NS_NewPipe2(getter_AddRefs(pipeIn), getter_AddRefs(pipeOut), true, true,
+              kSegmentSize,
+              nsIFaviconService::MAX_FAVICON_BUFFER_SIZE / kSegmentSize);
+
+  pipeIn.forget(inStream);
+  pipeOut.forget(outStream);
+}
+
+// static
+void PageIconProtocolHandler::NewSimpleChannel(
+    nsIURI* aURI, nsILoadInfo* aLoadInfo, RemoteStreamGetter* aStreamGetter,
+    nsIChannel** aRetVal) {
+  nsCOMPtr<nsIChannel> channel = NS_NewSimpleChannel(
+      aURI, aLoadInfo, aStreamGetter,
+      [](nsIStreamListener* listener, nsIChannel* simpleChannel,
+         RemoteStreamGetter* getter) -> RequestOrReason {
+        return getter->GetAsync(listener, simpleChannel,
+                                &NeckoChild::SendGetPageIconStream);
+      });
+
+  channel.swap(*aRetVal);
+}
+
+}  // namespace mozilla::places
diff --git a/toolkit/components/places/PageIconProtocolHandler.h b/toolkit/components/places/PageIconProtocolHandler.h
new file mode 100644
index 0000000000..7cfeeae99b
--- /dev/null
+++ b/toolkit/components/places/PageIconProtocolHandler.h
@@ -0,0 +1,94 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_PageIconProtocolHandler_h
+#define mozilla_places_PageIconProtocolHandler_h
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/net/RemoteStreamGetter.h"
+#include "nsIProtocolHandler.h"
+#include "nsThreadUtils.h"
+#include "nsWeakReference.h"
+
+namespace mozilla::places {
+
+struct FaviconMetadata;
+using FaviconMetadataPromise =
+    mozilla::MozPromise<FaviconMetadata, nsresult, false>;
+
+using net::RemoteStreamPromise;
+
+class PageIconProtocolHandler final : public nsIProtocolHandler,
+                                      public nsSupportsWeakReference {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPROTOCOLHANDLER
+
+  static already_AddRefed<PageIconProtocolHandler> GetSingleton() {
+    MOZ_ASSERT(NS_IsMainThread());
+    if (MOZ_UNLIKELY(!sSingleton)) {
+      sSingleton = new PageIconProtocolHandler();
+      ClearOnShutdown(&sSingleton);
+    }
+    return do_AddRef(sSingleton);
+  }
+
+  /**
+   * To be called in the parent process to obtain an input stream for the
+   * given icon.
+   *
+   * @param aChildURI a page-icon URI sent from the child.
+   * @param aLoadInfo the nsILoadInfo for the load attempt from the child.
+   * @param aTerminateSender out param set to true when the params are invalid
+   *        and indicate the child should be terminated. If |aChildURI| is
+   *        not a page-icon URI, the child is in an invalid state and
+   *        should be terminated. This outparam will be set synchronously.
+   *
+   * @return RemoteStreamPromise
+   *        The RemoteStreamPromise will resolve with an RemoteStreamInfo on
+   *        success, and reject with an nsresult on failure.
+   */
+  RefPtr<RemoteStreamPromise> NewStream(nsIURI* aChildURI,
+                                        nsILoadInfo* aLoadInfo,
+                                        bool* aTerminateSender);
+
+ private:
+  ~PageIconProtocolHandler() = default;
+
+  /**
+   * This replaces the provided channel with a channel that will proxy the load
+   * to the parent process.
+   *
+   * @param aURI the page-icon: URI.
+   * @param aLoadInfo the loadinfo for the request.
+   * @param aRetVal in/out channel param referring to the channel that
+   *        might need to be substituted with a remote channel.
+   * @return NS_OK if the replacement channel was created successfully.
+   *         Otherwise, returns an error.
+   */
+  Result<Ok, nsresult> SubstituteRemoteChannel(nsIURI* aURI,
+                                               nsILoadInfo* aLoadInfo,
+                                               nsIChannel** aRetVal);
+
+  RefPtr<FaviconMetadataPromise> GetFaviconData(nsIURI* aPageIconURI,
+                                                nsILoadInfo* aLoadInfo);
+
+  nsresult NewChannelInternal(nsIURI*, nsILoadInfo*, nsIChannel**);
+
+  void GetStreams(nsIAsyncInputStream** inStream,
+                  nsIAsyncOutputStream** outStream);
+
+  // Gets a SimpleChannel that wraps the provided channel.
+  static void NewSimpleChannel(nsIURI* aURI, nsILoadInfo* aLoadinfo,
+                               mozilla::net::RemoteStreamGetter* aStreamGetter,
+                               nsIChannel** aRetVal);
+  static StaticRefPtr<PageIconProtocolHandler> sSingleton;
+};
+
+}  // namespace mozilla::places
+
+#endif
diff --git a/toolkit/components/places/PlaceInfo.cpp b/toolkit/components/places/PlaceInfo.cpp
new file mode 100644
index 0000000000..fc489ddb78
--- /dev/null
+++ b/toolkit/components/places/PlaceInfo.cpp
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PlaceInfo.h"
+#include "VisitInfo.h"
+#include "nsIURI.h"
+#include "nsServiceManagerUtils.h"
+#include "nsIXPConnect.h"
+#include "jsapi.h"
+#include "js/Array.h"               // JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_DefineElement
+
+namespace mozilla {
+namespace places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// PlaceInfo
+
+PlaceInfo::PlaceInfo(int64_t aId, const nsCString& aGUID,
+                     already_AddRefed<nsIURI> aURI, const nsString& aTitle,
+                     int64_t aFrecency)
+    : mId(aId),
+      mGUID(aGUID),
+      mURI(aURI),
+      mTitle(aTitle),
+      mFrecency(aFrecency),
+      mVisitsAvailable(false) {
+  MOZ_ASSERT(mURI, "Must provide a non-null uri!");
+}
+
+PlaceInfo::PlaceInfo(int64_t aId, const nsCString& aGUID,
+                     already_AddRefed<nsIURI> aURI, const nsString& aTitle,
+                     int64_t aFrecency, const VisitsArray& aVisits)
+    : mId(aId),
+      mGUID(aGUID),
+      mURI(aURI),
+      mTitle(aTitle),
+      mFrecency(aFrecency),
+      mVisits(aVisits.Clone()),
+      mVisitsAvailable(true) {
+  MOZ_ASSERT(mURI, "Must provide a non-null uri!");
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIPlaceInfo
+
+NS_IMETHODIMP
+PlaceInfo::GetPlaceId(int64_t* _placeId) {
+  *_placeId = mId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlaceInfo::GetGuid(nsACString& _guid) {
+  _guid = mGUID;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlaceInfo::GetUri(nsIURI** _uri) {
+  NS_ADDREF(*_uri = mURI);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlaceInfo::GetTitle(nsAString& _title) {
+  _title = mTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlaceInfo::GetFrecency(int64_t* _frecency) {
+  *_frecency = mFrecency;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlaceInfo::GetVisits(JSContext* aContext,
+                     JS::MutableHandle<JS::Value> _visits) {
+  // If the visits data was not provided, return null rather
+  // than an empty array to distinguish this case from the case
+  // of a place without any visit.
+  if (!mVisitsAvailable) {
+    _visits.setNull();
+    return NS_OK;
+  }
+
+  // TODO bug 625913 when we use this in situations that have more than one
+  // visit here, we will likely want to make this cache the value.
+  JS::Rooted<JSObject*> visits(aContext, JS::NewArrayObject(aContext, 0));
+  NS_ENSURE_TRUE(visits, NS_ERROR_OUT_OF_MEMORY);
+
+  JS::Rooted<JSObject*> global(aContext, JS::CurrentGlobalOrNull(aContext));
+  NS_ENSURE_TRUE(global, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
+
+  for (VisitsArray::size_type idx = 0; idx < mVisits.Length(); idx++) {
+    JS::Rooted<JSObject*> jsobj(aContext);
+    nsresult rv = xpc->WrapNative(aContext, global, mVisits[idx],
+                                  NS_GET_IID(mozIVisitInfo), jsobj.address());
+    NS_ENSURE_SUCCESS(rv, rv);
+    NS_ENSURE_STATE(jsobj);
+
+    bool rc = JS_DefineElement(aContext, visits, idx, jsobj, JSPROP_ENUMERATE);
+    NS_ENSURE_TRUE(rc, NS_ERROR_UNEXPECTED);
+  }
+
+  _visits.setObject(*visits);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ISUPPORTS(PlaceInfo, mozIPlaceInfo)
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/PlaceInfo.h b/toolkit/components/places/PlaceInfo.h
new file mode 100644
index 0000000000..6363ae1386
--- /dev/null
+++ b/toolkit/components/places/PlaceInfo.h
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_PlaceInfo_h__
+#define mozilla_places_PlaceInfo_h__
+
+#include "mozIAsyncHistory.h"
+#include "nsCOMPtr.h"
+#include "nsIURI.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "mozilla/Attributes.h"
+
+class mozIVisitInfo;
+
+namespace mozilla {
+namespace places {
+
+class PlaceInfo final : public mozIPlaceInfo {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZIPLACEINFO
+
+  typedef nsTArray<nsCOMPtr<mozIVisitInfo> > VisitsArray;
+
+  PlaceInfo(int64_t aId, const nsCString& aGUID, already_AddRefed<nsIURI> aURI,
+            const nsString& aTitle, int64_t aFrecency);
+  PlaceInfo(int64_t aId, const nsCString& aGUID, already_AddRefed<nsIURI> aURI,
+            const nsString& aTitle, int64_t aFrecency,
+            const VisitsArray& aVisits);
+
+ private:
+  ~PlaceInfo() = default;
+
+  const int64_t mId;
+  const nsCString mGUID;
+  nsCOMPtr<nsIURI> mURI;
+  const nsString mTitle;
+  const int64_t mFrecency;
+  const VisitsArray mVisits;
+  bool mVisitsAvailable;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_PlaceInfo_h__
diff --git a/toolkit/components/places/PlacesBackups.sys.mjs b/toolkit/components/places/PlacesBackups.sys.mjs
new file mode 100644
index 0000000000..066eef4ec9
--- /dev/null
+++ b/toolkit/components/places/PlacesBackups.sys.mjs
@@ -0,0 +1,517 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab filetype=javascript
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  BookmarkJSONUtils: "resource://gre/modules/BookmarkJSONUtils.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(
+  lazy,
+  "filenamesRegex",
+  () =>
+    /^bookmarks-([0-9-]+)(?:_([0-9]+)){0,1}(?:_([a-z0-9=+-]{24})){0,1}\.(json(lz4)?)$/i
+);
+
+async function limitBackups(aMaxBackups, backupFiles) {
+  if (
+    typeof aMaxBackups == "number" &&
+    aMaxBackups > -1 &&
+    backupFiles.length >= aMaxBackups
+  ) {
+    let numberOfBackupsToDelete = backupFiles.length - aMaxBackups;
+    while (numberOfBackupsToDelete--) {
+      let oldestBackup = backupFiles.pop();
+      await IOUtils.remove(oldestBackup);
+    }
+  }
+}
+
+/**
+ * Appends meta-data information to a given filename.
+ */
+function appendMetaDataToFilename(aFilename, aMetaData) {
+  let matches = aFilename.match(lazy.filenamesRegex);
+  return (
+    "bookmarks-" +
+    matches[1] +
+    "_" +
+    aMetaData.count +
+    "_" +
+    aMetaData.hash +
+    "." +
+    matches[4]
+  );
+}
+
+/**
+ * Gets the hash from a backup filename.
+ *
+ * @return the extracted hash or null.
+ */
+function getHashFromFilename(aFilename) {
+  let matches = aFilename.match(lazy.filenamesRegex);
+  if (matches && matches[3]) {
+    return matches[3];
+  }
+  return null;
+}
+
+/**
+ * Given two filenames, checks if they contain the same date.
+ */
+function isFilenameWithSameDate(aSourceName, aTargetName) {
+  let sourceMatches = aSourceName.match(lazy.filenamesRegex);
+  let targetMatches = aTargetName.match(lazy.filenamesRegex);
+
+  return sourceMatches && targetMatches && sourceMatches[1] == targetMatches[1];
+}
+
+/**
+ * Given a filename, searches for another backup with the same date.
+ *
+ * @return path string or null.
+ */
+function getBackupFileForSameDate(aFilename) {
+  return (async function () {
+    let backupFiles = await PlacesBackups.getBackupFiles();
+    for (let backupFile of backupFiles) {
+      if (isFilenameWithSameDate(PathUtils.filename(backupFile), aFilename)) {
+        return backupFile;
+      }
+    }
+    return null;
+  })();
+}
+
+export var PlacesBackups = {
+  /**
+   * Matches the backup filename:
+   *  0: file name
+   *  1: date in form Y-m-d
+   *  2: bookmarks count
+   *  3: contents hash
+   *  4: file extension
+   */
+  get filenamesRegex() {
+    return lazy.filenamesRegex;
+  },
+
+  /**
+   * Gets backup folder asynchronously.
+   * @return {Promise}
+   * @resolve the folder (the folder string path).
+   */
+  getBackupFolder: function PB_getBackupFolder() {
+    return (async () => {
+      if (this._backupFolder) {
+        return this._backupFolder;
+      }
+      let backupsDirPath = PathUtils.join(
+        PathUtils.profileDir,
+        this.profileRelativeFolderPath
+      );
+      await IOUtils.makeDirectory(backupsDirPath);
+      return (this._backupFolder = backupsDirPath);
+    })();
+  },
+
+  get profileRelativeFolderPath() {
+    return "bookmarkbackups";
+  },
+
+  /**
+   * Cache current backups in a sorted (by date DESC) array.
+   * @return {Promise}
+   * @resolve a sorted array of string paths.
+   */
+  getBackupFiles: function PB_getBackupFiles() {
+    return (async () => {
+      if (this._backupFiles) {
+        return this._backupFiles;
+      }
+
+      this._backupFiles = [];
+
+      let backupFolderPath = await this.getBackupFolder();
+      let children = await IOUtils.getChildren(backupFolderPath);
+      let list = [];
+      for (const entry of children) {
+        // Since IOUtils I/O is serialized, we can safely remove .tmp files
+        // without risking to remove ongoing backups.
+        let filename = PathUtils.filename(entry);
+        if (filename.endsWith(".tmp")) {
+          list.push(IOUtils.remove(entry));
+          continue;
+        }
+
+        if (lazy.filenamesRegex.test(filename)) {
+          // Remove bogus backups in future dates.
+          if (this.getDateForFile(entry) > new Date()) {
+            list.push(IOUtils.remove(entry));
+            continue;
+          }
+          this._backupFiles.push(entry);
+        }
+      }
+      await Promise.all(list);
+
+      this._backupFiles.sort((a, b) => {
+        let aDate = this.getDateForFile(a);
+        let bDate = this.getDateForFile(b);
+        return bDate - aDate;
+      });
+
+      return this._backupFiles;
+    })();
+  },
+
+  /**
+   * Invalidates the internal cache for testing purposes.
+   */
+  invalidateCache() {
+    this._backupFiles = null;
+  },
+
+  /**
+   * Generates a ISO date string (YYYY-MM-DD) from a Date object.
+   *
+   * @param dateObj
+   *        The date object to parse.
+   * @return an ISO date string.
+   */
+  toISODateString: function toISODateString(dateObj) {
+    if (!dateObj || dateObj.constructor.name != "Date" || !dateObj.getTime()) {
+      throw new Error("invalid date object");
+    }
+    let padDate = val => ("0" + val).substr(-2, 2);
+    return [
+      dateObj.getFullYear(),
+      padDate(dateObj.getMonth() + 1),
+      padDate(dateObj.getDate()),
+    ].join("-");
+  },
+
+  /**
+   * Creates a filename for bookmarks backup files.
+   *
+   * @param [optional] aDateObj
+   *                   Date object used to build the filename.
+   *                   Will use current date if empty.
+   * @param [optional] bool - aCompress
+   *                   Determines if file extension is json or jsonlz4
+                       Default is json
+   * @return A bookmarks backup filename.
+   */
+  getFilenameForDate: function PB_getFilenameForDate(aDateObj, aCompress) {
+    let dateObj = aDateObj || new Date();
+    // Use YYYY-MM-DD (ISO 8601) as it doesn't contain illegal characters
+    // and makes the alphabetical order of multiple backup files more useful.
+    return (
+      "bookmarks-" +
+      PlacesBackups.toISODateString(dateObj) +
+      ".json" +
+      (aCompress ? "lz4" : "")
+    );
+  },
+
+  /**
+   * Creates a Date object from a backup file.  The date is the backup
+   * creation date.
+   *
+   * @param {Sring} aBackupFile The path of the backup.
+   * @return {Date} A Date object for the backup's creation time.
+   */
+  getDateForFile: function PB_getDateForFile(aBackupFile) {
+    let filename = PathUtils.filename(aBackupFile);
+    let matches = filename.match(lazy.filenamesRegex);
+    if (!matches) {
+      throw new Error(`Invalid backup file name: ${filename}`);
+    }
+    return new Date(matches[1].replace(/-/g, "/"));
+  },
+
+  /**
+   * Get the most recent backup file.
+   *
+   * @return {Promise}
+   * @result the path to the file.
+   */
+  getMostRecentBackup: function PB_getMostRecentBackup() {
+    return (async () => {
+      let entries = await this.getBackupFiles();
+      for (let entry of entries) {
+        let rx = /\.json(lz4)?$/;
+        if (PathUtils.filename(entry).match(rx)) {
+          return entry;
+        }
+      }
+      return null;
+    })();
+  },
+
+  /**
+   * Returns whether a recent enough backup exists, using these heuristic: if
+   * a backup exists, it should be newer than the last browser session date,
+   * otherwise it should not be older than maxDays.
+   * If the backup is older than the last session, the calculated time is
+   * reported to telemetry.
+   *
+   * @param [maxDays] The maximum number of days a backup can be old.
+   */
+  async hasRecentBackup({ maxDays = 3 } = {}) {
+    let lastBackupFile = await PlacesBackups.getMostRecentBackup();
+    if (!lastBackupFile) {
+      return false;
+    }
+    let lastBackupTime = PlacesBackups.getDateForFile(lastBackupFile);
+    let profileLastUse = Services.appinfo.replacedLockTime || Date.now();
+    if (lastBackupTime > profileLastUse) {
+      return true;
+    }
+    let backupAge = Math.round((profileLastUse - lastBackupTime) / 86400000);
+    // Telemetry the age of the last available backup.
+    try {
+      Services.telemetry
+        .getHistogramById("PLACES_BACKUPS_DAYSFROMLAST")
+        .add(backupAge);
+    } catch (ex) {
+      console.error(new Error("Unable to report telemetry."));
+    }
+    return backupAge <= maxDays;
+  },
+
+  /**
+   * Serializes bookmarks using JSON, and writes to the supplied file.
+   *
+   * @param aFilePath
+   *        path for the "bookmarks.json" file to be created.
+   * @return {Promise}
+   * @resolves the number of serialized uri nodes.
+   */
+  async saveBookmarksToJSONFile(aFilePath) {
+    let { count: nodeCount, hash: hash } =
+      await lazy.BookmarkJSONUtils.exportToFile(aFilePath);
+
+    let backupFolderPath = await this.getBackupFolder();
+    if (PathUtils.profileDir == backupFolderPath) {
+      // We are creating a backup in the default backups folder,
+      // so just update the internal cache.
+      if (!this._backupFiles) {
+        await this.getBackupFiles();
+      }
+      this._backupFiles.unshift(aFilePath);
+    } else {
+      let aMaxBackup = Services.prefs.getIntPref(
+        "browser.bookmarks.max_backups"
+      );
+      if (aMaxBackup === 0) {
+        if (!this._backupFiles) {
+          await this.getBackupFiles();
+        }
+        limitBackups(aMaxBackup, this._backupFiles);
+        return nodeCount;
+      }
+      // If we are saving to a folder different than our backups folder, then
+      // we also want to create a new compressed version in it.
+      // This way we ensure the latest valid backup is the same saved by the
+      // user.  See bug 424389.
+      let mostRecentBackupFile = await this.getMostRecentBackup();
+      if (
+        !mostRecentBackupFile ||
+        hash != getHashFromFilename(PathUtils.filename(mostRecentBackupFile))
+      ) {
+        let name = this.getFilenameForDate(undefined, true);
+        let newFilename = appendMetaDataToFilename(name, {
+          count: nodeCount,
+          hash,
+        });
+        let newFilePath = PathUtils.join(backupFolderPath, newFilename);
+        let backupFile = await getBackupFileForSameDate(name);
+        if (backupFile) {
+          // There is already a backup for today, replace it.
+          await IOUtils.remove(backupFile);
+          if (!this._backupFiles) {
+            await this.getBackupFiles();
+          } else {
+            this._backupFiles.shift();
+          }
+          this._backupFiles.unshift(newFilePath);
+        } else {
+          // There is no backup for today, add the new one.
+          if (!this._backupFiles) {
+            await this.getBackupFiles();
+          }
+          this._backupFiles.unshift(newFilePath);
+        }
+        let jsonString = await IOUtils.read(aFilePath);
+        await IOUtils.write(newFilePath, jsonString, {
+          compress: true,
+        });
+        await limitBackups(aMaxBackup, this._backupFiles);
+      }
+    }
+    return nodeCount;
+  },
+
+  /**
+   * Creates a dated backup in <profile>/bookmarkbackups.
+   * Stores the bookmarks using a lz4 compressed JSON file.
+   *
+   * @param [optional] int aMaxBackups
+   *                       The maximum number of backups to keep.  If set to 0
+   *                       all existing backups are removed and aForceBackup is
+   *                       ignored, so a new one won't be created.
+   * @param [optional] bool aForceBackup
+   *                        Forces creating a backup even if one was already
+   *                        created that day (overwrites).
+   * @return {Promise}
+   */
+  create: function PB_create(aMaxBackups, aForceBackup) {
+    return (async () => {
+      if (aMaxBackups === 0) {
+        // Backups are disabled, delete any existing one and bail out.
+        if (!this._backupFiles) {
+          await this.getBackupFiles();
+        }
+        await limitBackups(0, this._backupFiles);
+        return;
+      }
+
+      // Ensure to initialize _backupFiles
+      if (!this._backupFiles) {
+        await this.getBackupFiles();
+      }
+      let newBackupFilename = this.getFilenameForDate(undefined, true);
+      // If we already have a backup for today we should do nothing, unless we
+      // were required to enforce a new backup.
+      let backupFile = await getBackupFileForSameDate(newBackupFilename);
+      if (backupFile && !aForceBackup) {
+        return;
+      }
+
+      if (backupFile) {
+        // In case there is a backup for today we should recreate it.
+        this._backupFiles.shift();
+        await IOUtils.remove(backupFile);
+      }
+
+      // Now check the hash of the most recent backup, and try to create a new
+      // backup, if that fails due to hash conflict, just rename the old backup.
+      let mostRecentBackupFile = await this.getMostRecentBackup();
+      let mostRecentHash =
+        mostRecentBackupFile &&
+        getHashFromFilename(PathUtils.filename(mostRecentBackupFile));
+
+      // Save bookmarks to a backup file.
+      let backupFolder = await this.getBackupFolder();
+      let newBackupFile = PathUtils.join(backupFolder, newBackupFilename);
+      let newFilenameWithMetaData;
+      try {
+        let { count: nodeCount, hash: hash } =
+          await lazy.BookmarkJSONUtils.exportToFile(newBackupFile, {
+            compress: true,
+            failIfHashIs: mostRecentHash,
+          });
+        newFilenameWithMetaData = appendMetaDataToFilename(newBackupFilename, {
+          count: nodeCount,
+          hash,
+        });
+      } catch (ex) {
+        if (!ex.becauseSameHash) {
+          throw ex;
+        }
+        // The last backup already contained up-to-date information, just
+        // rename it as if it was today's backup.
+        this._backupFiles.shift();
+        newBackupFile = mostRecentBackupFile;
+        // Ensure we retain the proper extension when renaming
+        // the most recent backup file.
+        if (/\.json$/.test(PathUtils.filename(mostRecentBackupFile))) {
+          newBackupFilename = this.getFilenameForDate();
+        }
+        newFilenameWithMetaData = appendMetaDataToFilename(newBackupFilename, {
+          count: this.getBookmarkCountForFile(mostRecentBackupFile),
+          hash: mostRecentHash,
+        });
+      }
+
+      // Append metadata to the backup filename.
+      let newBackupFileWithMetadata = PathUtils.join(
+        backupFolder,
+        newFilenameWithMetaData
+      );
+      await IOUtils.move(newBackupFile, newBackupFileWithMetadata);
+      this._backupFiles.unshift(newBackupFileWithMetadata);
+
+      // Limit the number of backups.
+      await limitBackups(aMaxBackups, this._backupFiles);
+    })();
+  },
+
+  /**
+   * Gets the bookmark count for backup file.
+   *
+   * @param aFilePath
+   *        File path The backup file.
+   *
+   * @return the bookmark count or null.
+   */
+  getBookmarkCountForFile: function PB_getBookmarkCountForFile(aFilePath) {
+    let count = null;
+    let filename = PathUtils.filename(aFilePath);
+    let matches = filename.match(lazy.filenamesRegex);
+    if (matches && matches[2]) {
+      count = matches[2];
+    }
+    return count;
+  },
+
+  /**
+   * Gets a bookmarks tree representation usable to create backups in different
+   * file formats.  The root or the tree is PlacesUtils.bookmarks.rootGuid.
+   *
+   * @return an object representing a tree with the places root as its root.
+   *         Each bookmark is represented by an object having these properties:
+   *         * id: the item id (make this not enumerable after bug 824502)
+   *         * title: the title
+   *         * guid: unique id
+   *         * parent: item id of the parent folder, not enumerable
+   *         * index: the position in the parent
+   *         * dateAdded: microseconds from the epoch
+   *         * lastModified: microseconds from the epoch
+   *         * type: type of the originating node as defined in PlacesUtils
+   *         The following properties exist only for a subset of bookmarks:
+   *         * annos: array of annotations
+   *         * uri: url
+   *         * iconUri: favicon's url
+   *         * keyword: associated keyword
+   *         * charset: last known charset
+   *         * tags: csv string of tags
+   *         * root: string describing whether this represents a root
+   *         * children: array of child items in a folder
+   */
+  async getBookmarksTree() {
+    let startTime = Date.now();
+    let root = await lazy.PlacesUtils.promiseBookmarksTree(
+      lazy.PlacesUtils.bookmarks.rootGuid,
+      {
+        includeItemIds: true,
+      }
+    );
+
+    try {
+      Services.telemetry
+        .getHistogramById("PLACES_BACKUPS_BOOKMARKSTREE_MS")
+        .add(Date.now() - startTime);
+    } catch (ex) {
+      console.error("Unable to report telemetry.");
+    }
+    return [root, root.itemsCount];
+  },
+};
diff --git a/toolkit/components/places/PlacesDBUtils.sys.mjs b/toolkit/components/places/PlacesDBUtils.sys.mjs
new file mode 100644
index 0000000000..5cc2bfc631
--- /dev/null
+++ b/toolkit/components/places/PlacesDBUtils.sys.mjs
@@ -0,0 +1,1399 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab filetype=javascript
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const BYTES_PER_MEBIBYTE = 1048576;
+const MS_PER_DAY = 86400000;
+// Threshold value for removeOldCorruptDBs.
+// Corrupt DBs older than this value are removed.
+const CORRUPT_DB_RETAIN_DAYS = 14;
+
+// Seconds between maintenance runs.
+const MAINTENANCE_INTERVAL_SECONDS = 7 * 86400;
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesPreviews: "resource://gre/modules/PlacesPreviews.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+});
+
+export var PlacesDBUtils = {
+  _isShuttingDown: false,
+
+  _clearTaskQueue: false,
+  clearPendingTasks() {
+    PlacesDBUtils._clearTaskQueue = true;
+  },
+
+  /**
+   * Executes integrity check and common maintenance tasks.
+   *
+   * @return a Map[taskName(String) -> Object]. The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task.
+   */
+  async maintenanceOnIdle() {
+    let tasks = [
+      this.checkIntegrity,
+      this.checkCoherence,
+      this._refreshUI,
+      this.incrementalVacuum,
+      this.removeOldCorruptDBs,
+      this.deleteOrphanPreviews,
+    ];
+    let telemetryStartTime = Date.now();
+    let taskStatusMap = await PlacesDBUtils.runTasks(tasks);
+
+    Services.prefs.setIntPref(
+      "places.database.lastMaintenance",
+      parseInt(Date.now() / 1000)
+    );
+    Services.telemetry
+      .getHistogramById("PLACES_IDLE_MAINTENANCE_TIME_MS")
+      .add(Date.now() - telemetryStartTime);
+    return taskStatusMap;
+  },
+
+  /**
+   * Executes integrity check, common and advanced maintenance tasks (like
+   * expiration and vacuum).  Will also collect statistics on the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise}
+   *        A promise that resolves with a Map[taskName(String) -> Object].
+   *        The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task.
+   */
+  async checkAndFixDatabase() {
+    let tasks = [
+      this.checkIntegrity,
+      this.checkCoherence,
+      this.expire,
+      this.vacuum,
+      this.stats,
+      this._refreshUI,
+    ];
+    return PlacesDBUtils.runTasks(tasks);
+  },
+
+  /**
+   * Forces a full refresh of Places views.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @returns {Array} An empty array.
+   */
+  async _refreshUI() {
+    PlacesObservers.notifyListeners([new PlacesPurgeCaches()]);
+    return [];
+  },
+
+  /**
+   * Checks integrity and tries to fix the database through a reindex.
+   *
+   * @return {Promise} resolves if database is sane or is made sane.
+   * @resolves to an array of logs for this task.
+   * @rejects if we're unable to fix corruption or unable to check status.
+   */
+  async checkIntegrity() {
+    let logs = [];
+
+    async function check(dbName) {
+      try {
+        await integrity(dbName);
+        logs.push(`The ${dbName} database is sane`);
+      } catch (ex) {
+        PlacesDBUtils.clearPendingTasks();
+        if (ex.result == Cr.NS_ERROR_FILE_CORRUPTED) {
+          logs.push(`The ${dbName} database is corrupt`);
+          Services.prefs.setCharPref(
+            "places.database.replaceDatabaseOnStartup",
+            dbName
+          );
+          throw new Error(
+            `Unable to fix corruption, ${dbName} will be replaced on next startup`
+          );
+        }
+        throw new Error(`Unable to check ${dbName} integrity: ${ex}`);
+      }
+    }
+
+    await check("places.sqlite");
+    await check("favicons.sqlite");
+
+    return logs;
+  },
+
+  /**
+   * Checks data coherence and tries to fix most common errors.
+   *
+   * @return {Promise} resolves when coherence is checked.
+   * @resolves to an array of logs for this task.
+   * @rejects if database is not coherent.
+   */
+  async checkCoherence() {
+    let logs = [];
+    let stmts = await PlacesDBUtils._getCoherenceStatements();
+    let coherenceCheck = true;
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: coherence check:",
+      db =>
+        db.executeTransaction(async () => {
+          for (let { query, params } of stmts) {
+            try {
+              await db.execute(query, params || null);
+            } catch (ex) {
+              console.error(ex);
+              coherenceCheck = false;
+            }
+          }
+        })
+    );
+
+    if (coherenceCheck) {
+      logs.push("The database is coherent");
+    } else {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error("Unable to complete the coherence check");
+    }
+    return logs;
+  },
+
+  /**
+   * Runs incremental vacuum on databases supporting it.
+   *
+   * @return {Promise} resolves when done.
+   * @resolves to an array of logs for this task.
+   * @rejects if we were unable to vacuum.
+   */
+  async incrementalVacuum() {
+    let logs = [];
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: incrementalVacuum",
+      async db => {
+        let count = (
+          await db.execute("PRAGMA favicons.freelist_count")
+        )[0].getResultByIndex(0);
+        if (count < 10) {
+          logs.push(
+            `The favicons database has only ${count} free pages, not vacuuming.`
+          );
+        } else {
+          logs.push(
+            `The favicons database has ${count} free pages, vacuuming.`
+          );
+          await db.execute("PRAGMA favicons.incremental_vacuum");
+          count = (
+            await db.execute("PRAGMA favicons.freelist_count")
+          )[0].getResultByIndex(0);
+          logs.push(
+            `The database has been vacuumed and has now ${count} free pages.`
+          );
+        }
+        return logs;
+      }
+    ).catch(ex => {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error(
+        "Unable to incrementally vacuum the favicons database " + ex
+      );
+    });
+  },
+
+  /**
+   * Expire orphan previews that don't have a Places entry anymore.
+   *
+   * @return {Promise} resolves when done.
+   * @resolves to an array of logs for this task.
+   */
+  async deleteOrphanPreviews() {
+    let logs = [];
+    try {
+      let deleted = await lazy.PlacesPreviews.deleteOrphans();
+      if (deleted) {
+        logs.push(`Orphan previews deleted.`);
+      }
+    } catch (ex) {
+      throw new Error("Unable to delete orphan previews " + ex);
+    }
+    return logs;
+  },
+
+  async _getCoherenceStatements() {
+    let cleanupStatements = [
+      // MOZ_PLACES
+      // L.1 remove duplicate URLs.
+      // This task uses a temp table of potential dupes, and a trigger to remove
+      // them. It runs first because it relies on subsequent tasks to clean up
+      // orphaned foreign key references. The task works like this: first, we
+      // insert all rows with the same hash into the temp table. This lets
+      // SQLite use the `url_hash` index for scanning `moz_places`. Hashes
+      // aren't unique, so two different URLs might have the same hash. To find
+      // the actual dupes, we use a unique constraint on the URL in the temp
+      // table. If that fails, we bump the dupe count. Then, we delete all dupes
+      // from the table. This fires the cleanup trigger, which updates all
+      // foreign key references to point to one of the duplicate Places, then
+      // deletes the others.
+      {
+        query: `CREATE TEMP TABLE IF NOT EXISTS moz_places_dupes_temp(
+          id INTEGER PRIMARY KEY
+        , hash INTEGER NOT NULL
+        , url TEXT UNIQUE NOT NULL
+        , count INTEGER NOT NULL DEFAULT 0
+        )`,
+      },
+      {
+        query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_places_remove_dupes_temp_trigger
+        AFTER DELETE ON moz_places_dupes_temp
+        FOR EACH ROW
+        BEGIN
+          /* Reassign history visits. */
+          UPDATE moz_historyvisits SET
+            place_id = OLD.id
+          WHERE place_id IN (SELECT id FROM moz_places
+                             WHERE id <> OLD.id AND
+                                   url_hash = OLD.hash AND
+                                   url = OLD.url);
+
+          /* Merge autocomplete history entries. */
+          INSERT INTO moz_inputhistory(place_id, input, use_count)
+          SELECT OLD.id, a.input, a.use_count
+          FROM moz_inputhistory a
+          JOIN moz_places h ON h.id = a.place_id
+          WHERE h.id <> OLD.id AND
+                h.url_hash = OLD.hash AND
+                h.url = OLD.url
+          ON CONFLICT(place_id, input) DO UPDATE SET
+            place_id = excluded.place_id,
+            use_count = use_count + excluded.use_count;
+
+          /* Merge page annos, ignoring annos with the same name that are
+             already set on the destination. */
+          INSERT OR IGNORE INTO moz_annos(id, place_id, anno_attribute_id,
+                                          content, flags, expiration, type,
+                                          dateAdded, lastModified)
+          SELECT (SELECT k.id FROM moz_annos k
+                  WHERE k.place_id = OLD.id AND
+                        k.anno_attribute_id = a.anno_attribute_id), OLD.id,
+                 a.anno_attribute_id, a.content, a.flags, a.expiration, a.type,
+                 a.dateAdded, a.lastModified
+          FROM moz_annos a
+          JOIN moz_places h ON h.id = a.place_id
+          WHERE h.id <> OLD.id AND
+                url_hash = OLD.hash AND
+                url = OLD.url;
+
+          /* Reassign bookmarks, and bump the Sync change counter just in case
+             we have new keywords. */
+          UPDATE moz_bookmarks SET
+            fk = OLD.id,
+            syncChangeCounter = syncChangeCounter + 1
+          WHERE fk IN (SELECT id FROM moz_places
+                       WHERE url_hash = OLD.hash AND
+                             url = OLD.url);
+
+          /* Reassign keywords. */
+          UPDATE moz_keywords SET
+            place_id = OLD.id
+          WHERE place_id IN (SELECT id FROM moz_places
+                             WHERE id <> OLD.id AND
+                                   url_hash = OLD.hash AND
+                                   url = OLD.url);
+
+          /* Now that we've updated foreign key references, drop the
+             conflicting source. */
+          DELETE FROM moz_places
+          WHERE id <> OLD.id AND
+                url_hash = OLD.hash AND
+                url = OLD.url;
+
+          /* Recalculate frecency for the destination. */
+          UPDATE moz_places SET recalc_frecency = 1, recalc_alt_frecency = 1
+          WHERE id = OLD.id;
+        END`,
+      },
+      {
+        query: `INSERT INTO moz_places_dupes_temp(id, hash, url, count)
+        SELECT h.id, h.url_hash, h.url, 1
+        FROM moz_places h
+        JOIN (SELECT url_hash FROM moz_places
+              GROUP BY url_hash
+              HAVING count(*) > 1) d ON d.url_hash = h.url_hash
+        ON CONFLICT(url) DO UPDATE SET
+          count = count + 1`,
+      },
+      { query: `DELETE FROM moz_places_dupes_temp WHERE count > 1` },
+      { query: `DROP TABLE moz_places_dupes_temp` },
+
+      // MOZ_ANNO_ATTRIBUTES
+      // A.1 remove obsolete annotations from moz_annos.
+      // The 'weave0' idiom exploits character ordering (0 follows /) to
+      // efficiently select all annos with a 'weave/' prefix.
+      {
+        query: `DELETE FROM moz_annos
+        WHERE type = 4 OR anno_attribute_id IN (
+          SELECT id FROM moz_anno_attributes
+          WHERE name = 'downloads/destinationFileName' OR
+                name BETWEEN 'weave/' AND 'weave0'
+        )`,
+      },
+
+      // A.3 remove unused attributes.
+      {
+        query: `DELETE FROM moz_anno_attributes WHERE id IN (
+          SELECT id FROM moz_anno_attributes n
+          WHERE NOT EXISTS
+              (SELECT id FROM moz_annos WHERE anno_attribute_id = n.id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_ANNOS
+      // B.1 remove annos with an invalid attribute
+      {
+        query: `DELETE FROM moz_annos WHERE id IN (
+          SELECT id FROM moz_annos a
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_anno_attributes
+              WHERE id = a.anno_attribute_id LIMIT 1)
+        )`,
+      },
+
+      // B.2 remove orphan annos
+      {
+        query: `DELETE FROM moz_annos WHERE id IN (
+          SELECT id FROM moz_annos a
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = a.place_id LIMIT 1)
+        )`,
+      },
+
+      // D.1 remove items that are not uri bookmarks from tag containers
+      {
+        query: `DELETE FROM moz_bookmarks WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE b.parent IN
+            (SELECT id FROM moz_bookmarks WHERE parent = :tags_folder)
+            AND b.type <> :bookmark_type
+        )`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.2 remove empty tags
+      {
+        query: `DELETE FROM moz_bookmarks WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE b.id IN
+            (SELECT id FROM moz_bookmarks WHERE parent = :tags_folder)
+            AND NOT EXISTS
+              (SELECT id from moz_bookmarks WHERE parent = b.id LIMIT 1)
+        )`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.3 move orphan items to unsorted folder
+      {
+        query: `UPDATE moz_bookmarks SET
+          parent = (SELECT id FROM moz_bookmarks WHERE guid = :unfiledGuid)
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT b.id FROM moz_bookmarks b
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_bookmarks WHERE id = b.parent LIMIT 1)
+        )`,
+        params: {
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.4 Insert tombstones for any synced items with the wrong type.
+      // Sync doesn't support changing the type of an existing item while
+      // keeping its GUID. To avoid confusing other clients, we insert
+      // tombstones for all synced items with the wrong type, so that we
+      // can reupload them with the correct type and a new GUID.
+      {
+        query: `INSERT OR IGNORE INTO moz_bookmarks_deleted(guid, dateRemoved)
+                SELECT guid, :dateRemoved
+                FROM moz_bookmarks
+                WHERE syncStatus <> :syncStatus AND
+                      ((type IN (:folder_type, :separator_type) AND
+                        fk NOTNULL) OR
+                       (type = :bookmark_type AND
+                        fk IS NULL) OR
+                       type IS NULL)`,
+        params: {
+          dateRemoved: lazy.PlacesUtils.toPRTime(new Date()),
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        },
+      },
+
+      // D.5 fix wrong item types
+      // Folders and separators should not have an fk.
+      // If they have a valid fk, convert them to bookmarks, and give them new
+      // GUIDs. If the item has children, we'll move them to the unfiled root
+      // in D.8. If the `fk` doesn't exist in `moz_places`, we'll remove the
+      // item in D.9.
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = :bookmark_type
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE type IN (:folder_type, :separator_type)
+            AND fk NOTNULL
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.6 fix wrong item types
+      // Bookmarks should have an fk, if they don't have any, convert them to
+      // folders.
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = :folder_type
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE type = :bookmark_type
+            AND fk IS NULL
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.7 fix wrong item types
+      // `moz_bookmarks.type` doesn't have a NOT NULL constraint, so it's
+      // possible for an item to not have a type (bug 1586427).
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            type = CASE WHEN fk NOT NULL THEN :bookmark_type ELSE :folder_type END
+        WHERE guid NOT IN (
+         :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND type IS NULL`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.8 fix wrong parents
+      // Items cannot have separators or other bookmarks
+      // as parent, if they have bad parent move them to unsorted bookmarks.
+      {
+        query: `UPDATE moz_bookmarks SET
+          parent = (SELECT id FROM moz_bookmarks WHERE guid = :unfiledGuid)
+        WHERE guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND id IN (
+          SELECT id FROM moz_bookmarks b
+          WHERE EXISTS
+            (SELECT id FROM moz_bookmarks WHERE id = b.parent
+              AND type IN (:bookmark_type, :separator_type)
+              LIMIT 1)
+        )`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          separator_type: lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.9 remove items without a valid place
+      // We've already converted folders with an `fk` to bookmarks in D.5,
+      // and bookmarks without an `fk` to folders in D.6. However, the `fk`
+      // might not reference an existing `moz_places.id`, even if it's
+      // NOT NULL. This statement takes care of those.
+      {
+        query: `DELETE FROM moz_bookmarks AS b
+        WHERE b.guid NOT IN (
+          :rootGuid, :menuGuid, :toolbarGuid, :unfiledGuid, :tagsGuid  /* skip roots */
+        ) AND b.fk NOT NULL
+          AND b.type = :bookmark_type
+          AND NOT EXISTS (SELECT 1 FROM moz_places h WHERE h.id = b.fk)`,
+        params: {
+          bookmark_type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          rootGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+          menuGuid: lazy.PlacesUtils.bookmarks.menuGuid,
+          toolbarGuid: lazy.PlacesUtils.bookmarks.toolbarGuid,
+          unfiledGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+          tagsGuid: lazy.PlacesUtils.bookmarks.tagsGuid,
+        },
+      },
+
+      // D.10 fix non-consecutive positions.
+      {
+        query: `
+          WITH positions(item_id, pos, seq) AS (
+            SELECT id, position AS pos,
+                   (row_number() OVER (PARTITION BY parent ORDER BY position)) - 1 AS seq
+            FROM moz_bookmarks
+          )
+          UPDATE moz_bookmarks
+          SET position = seq
+          FROM positions
+          WHERE item_id = moz_bookmarks.id AND seq <> pos`,
+      },
+
+      // D.12 Fix empty-named tags.
+      // Tags were allowed to have empty names due to a UI bug.  Fix them by
+      // replacing their title with "(notitle)", and bumping the change counter
+      // for all bookmarks with the fixed tags.
+      {
+        query: `UPDATE moz_bookmarks SET syncChangeCounter = syncChangeCounter + 1
+         WHERE fk IN (SELECT b.fk FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      WHERE length(p.title) = 0 AND p.type = :folder_type AND
+                            p.parent = :tags_folder)`,
+        params: {
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+      {
+        query: `UPDATE moz_bookmarks SET title = :empty_title
+        WHERE length(title) = 0 AND type = :folder_type
+          AND parent = :tags_folder`,
+        params: {
+          empty_title: "(notitle)",
+          folder_type: lazy.PlacesUtils.bookmarks.TYPE_FOLDER,
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+
+      // MOZ_ICONS
+      // E.1 remove orphan icon entries.
+      {
+        query: `DELETE FROM moz_pages_w_icons WHERE page_url_hash NOT IN (
+          SELECT url_hash FROM moz_places
+        )`,
+      },
+
+      // Remove icons whose origin is not in moz_origins, unless referenced.
+      {
+        query: `DELETE FROM moz_icons WHERE id IN (
+          SELECT id FROM moz_icons WHERE root = 0
+          UNION ALL
+          SELECT id FROM moz_icons
+          WHERE root = 1
+            AND get_host_and_port(icon_url) NOT IN (SELECT host FROM moz_origins)
+            AND fixup_url(get_host_and_port(icon_url)) NOT IN (SELECT host FROM moz_origins)
+          EXCEPT
+          SELECT icon_id FROM moz_icons_to_pages
+        )`,
+      },
+
+      // MOZ_HISTORYVISITS
+      // F.1 remove orphan visits
+      {
+        query: `DELETE FROM moz_historyvisits WHERE id IN (
+          SELECT id FROM moz_historyvisits v
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = v.place_id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_INPUTHISTORY
+      // G.1 remove orphan input history
+      {
+        query: `DELETE FROM moz_inputhistory WHERE place_id IN (
+          SELECT place_id FROM moz_inputhistory i
+          WHERE NOT EXISTS
+            (SELECT id FROM moz_places WHERE id = i.place_id LIMIT 1)
+        )`,
+      },
+
+      // MOZ_KEYWORDS
+      // I.1 remove unused keywords
+      {
+        query: `DELETE FROM moz_keywords WHERE id IN (
+          SELECT id FROM moz_keywords k
+          WHERE NOT EXISTS
+            (SELECT 1 FROM moz_places h WHERE k.place_id = h.id)
+        )`,
+      },
+
+      // MOZ_PLACES
+      // L.2 recalculate visit_count and last_visit_date
+      {
+        query: `UPDATE moz_places
+        SET visit_count = (SELECT count(*) FROM moz_historyvisits
+                            WHERE place_id = moz_places.id AND visit_type NOT IN (0,4,7,8,9)),
+            last_visit_date = (SELECT MAX(visit_date) FROM moz_historyvisits
+                                WHERE place_id = moz_places.id)
+        WHERE id IN (
+          SELECT h.id FROM moz_places h
+          WHERE visit_count <> (SELECT count(*) FROM moz_historyvisits v
+                                WHERE v.place_id = h.id AND visit_type NOT IN (0,4,7,8,9))
+              OR last_visit_date IS NOT
+                (SELECT MAX(visit_date) FROM moz_historyvisits v WHERE v.place_id = h.id)
+        )`,
+      },
+
+      // L.3 recalculate hidden for redirects.
+      {
+        query: `UPDATE moz_places
+        SET hidden = 1
+        WHERE id IN (
+          SELECT h.id FROM moz_places h
+          JOIN moz_historyvisits src ON src.place_id = h.id
+          JOIN moz_historyvisits dst ON dst.from_visit = src.id AND dst.visit_type IN (5,6)
+          LEFT JOIN moz_bookmarks on fk = h.id AND fk ISNULL
+          GROUP BY src.place_id HAVING count(*) = visit_count
+        )`,
+      },
+
+      // L.4 recalculate foreign_count.
+      {
+        query: `UPDATE moz_places SET foreign_count =
+          (SELECT count(*) FROM moz_bookmarks WHERE fk = moz_places.id ) +
+          (SELECT count(*) FROM moz_keywords WHERE place_id = moz_places.id )`,
+      },
+
+      // L.5 recalculate missing hashes.
+      {
+        query: `UPDATE moz_places SET url_hash = hash(url) WHERE url_hash = 0`,
+      },
+
+      // L.6 fix invalid Place GUIDs.
+      {
+        query: `UPDATE moz_places
+        SET guid = GENERATE_GUID()
+        WHERE guid IS NULL OR
+              NOT IS_VALID_GUID(guid)`,
+      },
+
+      // MOZ_BOOKMARKS
+      // S.1 fix invalid GUIDs for synced bookmarks.
+      // This requires multiple related statements.
+      // First, we insert tombstones for all synced bookmarks with invalid
+      // GUIDs, so that we can delete them on the server. Second, we add a
+      // temporary trigger to bump the change counter for the parents of any
+      // items we update, since Sync stores the list of child GUIDs on the
+      // parent. Finally, we assign new GUIDs for all items with missing and
+      // invalid GUIDs, bump their change counters, and reset their sync
+      // statuses to NEW so that they're considered for deduping.
+      {
+        query: `INSERT OR IGNORE INTO moz_bookmarks_deleted(guid, dateRemoved)
+        SELECT guid, :dateRemoved
+        FROM moz_bookmarks
+        WHERE syncStatus <> :syncStatus AND
+              guid NOT NULL AND
+              NOT IS_VALID_GUID(guid)`,
+        params: {
+          dateRemoved: lazy.PlacesUtils.toPRTime(new Date()),
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        },
+      },
+      {
+        query: `UPDATE moz_bookmarks
+        SET guid = GENERATE_GUID(),
+            syncStatus = :syncStatus
+        WHERE guid IS NULL OR
+              NOT IS_VALID_GUID(guid)`,
+        params: {
+          syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        },
+      },
+
+      // S.2 drop tombstones for bookmarks that aren't deleted.
+      {
+        query: `DELETE FROM moz_bookmarks_deleted
+        WHERE guid IN (SELECT guid FROM moz_bookmarks)`,
+      },
+
+      // S.3 set missing added and last modified dates.
+      {
+        query: `UPDATE moz_bookmarks
+        SET dateAdded = COALESCE(NULLIF(dateAdded, 0), NULLIF(lastModified, 0), NULLIF((
+              SELECT MIN(visit_date) FROM moz_historyvisits
+              WHERE place_id = fk
+            ), 0), STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000),
+            lastModified = COALESCE(NULLIF(lastModified, 0), NULLIF(dateAdded, 0), NULLIF((
+              SELECT MAX(visit_date) FROM moz_historyvisits
+              WHERE place_id = fk
+            ), 0), STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000)
+        WHERE NULLIF(dateAdded, 0) IS NULL OR
+              NULLIF(lastModified, 0) IS NULL`,
+      },
+
+      // S.4 reset added dates that are ahead of last modified dates.
+      {
+        query: `UPDATE moz_bookmarks
+         SET dateAdded = lastModified
+         WHERE dateAdded > lastModified`,
+      },
+    ];
+
+    // Create triggers for updating Sync metadata. The "sync change" trigger
+    // bumps the parent's change counter when we update a GUID or move an item
+    // to a different folder, since Sync stores the list of child GUIDs on the
+    // parent. The "sync tombstone" trigger inserts tombstones for deleted
+    // synced bookmarks.
+    cleanupStatements.unshift({
+      query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_bm_sync_change_temp_trigger
+      AFTER UPDATE OF guid, parent, position ON moz_bookmarks
+      FOR EACH ROW
+      BEGIN
+        UPDATE moz_bookmarks
+        SET syncChangeCounter = syncChangeCounter + 1
+        WHERE id IN (OLD.parent, NEW.parent, NEW.id);
+      END`,
+    });
+    cleanupStatements.unshift({
+      query: `CREATE TEMP TRIGGER IF NOT EXISTS moz_bm_sync_tombstone_temp_trigger
+      AFTER DELETE ON moz_bookmarks
+      FOR EACH ROW WHEN OLD.guid NOT NULL AND
+                        OLD.syncStatus <> 1
+      BEGIN
+        UPDATE moz_bookmarks
+        SET syncChangeCounter = syncChangeCounter + 1
+        WHERE id = OLD.parent;
+
+        INSERT INTO moz_bookmarks_deleted(guid, dateRemoved)
+        VALUES(OLD.guid, STRFTIME('%s', 'now', 'localtime', 'utc') * 1000000);
+      END`,
+    });
+    cleanupStatements.push({
+      query: `DROP TRIGGER moz_bm_sync_change_temp_trigger`,
+    });
+    cleanupStatements.push({
+      query: `DROP TRIGGER moz_bm_sync_tombstone_temp_trigger`,
+    });
+
+    return cleanupStatements;
+  },
+
+  /**
+   * Tries to vacuum the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise} resolves when database is vacuumed.
+   * @resolves to an array of logs for this task.
+   * @rejects if we are unable to vacuum database.
+   */
+  async vacuum() {
+    let logs = [];
+    let placesDbPath = PathUtils.join(PathUtils.profileDir, "places.sqlite");
+    let info = await IOUtils.stat(placesDbPath);
+    logs.push(`Initial database size is ${parseInt(info.size / 1024)}KiB`);
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: vacuum",
+      async db => {
+        await db.execute("VACUUM");
+        logs.push("The database has been vacuumed");
+        info = await IOUtils.stat(placesDbPath);
+        logs.push(`Final database size is ${parseInt(info.size / 1024)}KiB`);
+        return logs;
+      }
+    ).catch(() => {
+      PlacesDBUtils.clearPendingTasks();
+      throw new Error("Unable to vacuum database");
+    });
+  },
+
+  /**
+   * Forces a full expiration on the database.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   * @return {Promise} resolves when the database in cleaned up.
+   * @resolves to an array of logs for this task.
+   */
+  async expire() {
+    let logs = [];
+
+    let expiration = Cc["@mozilla.org/places/expiration;1"].getService(
+      Ci.nsIObserver
+    );
+
+    let returnPromise = new Promise(res => {
+      let observer = (subject, topic, data) => {
+        Services.obs.removeObserver(observer, topic);
+        logs.push("Database cleaned up");
+        res(logs);
+      };
+      Services.obs.addObserver(
+        observer,
+        lazy.PlacesUtils.TOPIC_EXPIRATION_FINISHED
+      );
+    });
+
+    // Force an orphans expiration step.
+    expiration.observe(null, "places-debug-start-expiration", 0);
+    return returnPromise;
+  },
+
+  /**
+   * Collects statistical data on the database.
+   *
+   * @return {Promise} resolves when statistics are collected.
+   * @resolves to an array of logs for this task.
+   * @rejects if we are unable to collect stats for some reason.
+   */
+  async stats() {
+    let logs = [];
+    let placesDbPath = PathUtils.join(PathUtils.profileDir, "places.sqlite");
+    let info = await IOUtils.stat(placesDbPath);
+    logs.push(`Places.sqlite size is ${parseInt(info.size / 1024)}KiB`);
+    let faviconsDbPath = PathUtils.join(
+      PathUtils.profileDir,
+      "favicons.sqlite"
+    );
+    info = await IOUtils.stat(faviconsDbPath);
+    logs.push(`Favicons.sqlite size is ${parseInt(info.size / 1024)}KiB`);
+
+    // Execute each step async.
+    let pragmas = [
+      "user_version",
+      "page_size",
+      "cache_size",
+      "journal_mode",
+      "synchronous",
+    ].map(p => `pragma_${p}`);
+    let pragmaQuery = `SELECT * FROM ${pragmas.join(", ")}`;
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesDBUtils: pragma for stats",
+      async db => {
+        let row = (await db.execute(pragmaQuery))[0];
+        for (let i = 0; i != pragmas.length; i++) {
+          logs.push(`${pragmas[i]} is ${row.getResultByIndex(i)}`);
+        }
+      }
+    ).catch(() => {
+      logs.push("Could not set pragma for stat collection");
+    });
+
+    // Get maximum number of unique URIs.
+    try {
+      let limitURIs = await Cc["@mozilla.org/places/expiration;1"]
+        .getService(Ci.nsISupports)
+        .wrappedJSObject.getPagesLimit();
+      logs.push(
+        "History can store a maximum of " + limitURIs + " unique pages"
+      );
+    } catch (ex) {}
+
+    let query = "SELECT name FROM sqlite_master WHERE type = :type";
+    let params = {};
+    let _getTableCount = async tableName => {
+      let db = await lazy.PlacesUtils.promiseDBConnection();
+      let rows = await db.execute(`SELECT count(*) FROM ${tableName}`);
+      logs.push(
+        `Table ${tableName} has ${rows[0].getResultByIndex(0)} records`
+      );
+    };
+
+    try {
+      params.type = "table";
+      let db = await lazy.PlacesUtils.promiseDBConnection();
+      await db.execute(query, params, r =>
+        _getTableCount(r.getResultByIndex(0))
+      );
+    } catch (ex) {
+      throw new Error("Unable to collect stats.");
+    }
+
+    let details = await PlacesDBUtils.getEntitiesStats();
+    logs.push(
+      `Pages sequentiality: ${details.get("moz_places").sequentialityPerc}`
+    );
+    let entities = Array.from(details.keys()).sort((a, b) => {
+      return details.get(a).sizePerc - details.get(b).sizePerc;
+    });
+    for (let key of entities) {
+      let info = details.get(key);
+      logs.push(
+        `${key}: ${info.sizeBytes / 1024}KiB (${info.sizePerc}%), ${
+          info.efficiencyPerc
+        }% eff.`
+      );
+    }
+
+    return logs;
+  },
+
+  /**
+   * Collects telemetry data and reports it to Telemetry.
+   *
+   * Note: although this function isn't actually async, we keep it async to
+   * allow us to maintain a simple, consistent API for the tasks within this object.
+   *
+   */
+  async telemetry() {
+    // This will be populated with one integer property for each probe result,
+    // using the histogram name as key.
+    let probeValues = {};
+
+    // The following array contains an ordered list of entries that are
+    // processed to collect telemetry data.  Each entry has these properties:
+    //
+    //  histogram: Name of the telemetry histogram to update.
+    //  query:     This is optional.  If present, contains a database command
+    //             that will be executed asynchronously, and whose result will
+    //             be added to the telemetry histogram.
+    //  callback:  This is optional.  If present, contains a function that must
+    //             return the value that will be added to the telemetry
+    //             histogram. If a query is also present, its result is passed
+    //             as the first argument of the function.  If the function
+    //             raises an exception, no data is added to the histogram.
+    //
+    // Since all queries are executed in order by the database backend, the
+    // callbacks can also use the result of previous queries stored in the
+    // probeValues object.
+    let probes = [
+      {
+        histogram: "PLACES_PAGES_COUNT",
+        query: "SELECT count(*) FROM moz_places",
+      },
+
+      {
+        histogram: "PLACES_BOOKMARKS_COUNT",
+        query: `SELECT count(*) FROM moz_bookmarks b
+                    JOIN moz_bookmarks t ON t.id = b.parent
+                    AND t.parent <> :tags_folder
+                    WHERE b.type = :type_bookmark`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_TAGS_COUNT",
+        query: `SELECT count(*) FROM moz_bookmarks
+                    WHERE parent = :tags_folder`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+        },
+      },
+
+      {
+        histogram: "PLACES_KEYWORDS_COUNT",
+        query: "SELECT count(*) FROM moz_keywords",
+      },
+
+      {
+        histogram: "PLACES_SORTED_BOOKMARKS_PERC",
+        query: `SELECT IFNULL(ROUND((
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      JOIN moz_bookmarks g ON g.id = p.parent
+                      WHERE g.guid <> :root_guid
+                        AND g.guid <> :tags_guid
+                        AND b.type  = :type_bookmark
+                      ) * 100 / (
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks p ON p.id = b.parent
+                      JOIN moz_bookmarks g ON g.id = p.parent
+                      AND g.guid <> :tags_guid
+                      WHERE b.type = :type_bookmark
+                    )), 0)`,
+        params: {
+          root_guid: lazy.PlacesUtils.bookmarks.rootGuid,
+          tags_guid: lazy.PlacesUtils.bookmarks.tagsGuid,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_TAGGED_BOOKMARKS_PERC",
+        query: `SELECT IFNULL(ROUND((
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks t ON t.id = b.parent
+                      AND t.parent = :tags_folder
+                      ) * 100 / (
+                      SELECT count(*) FROM moz_bookmarks b
+                      JOIN moz_bookmarks t ON t.id = b.parent
+                      AND t.parent <> :tags_folder
+                      WHERE b.type = :type_bookmark
+                    )), 0)`,
+        params: {
+          tags_folder: lazy.PlacesUtils.tagsFolderId,
+          type_bookmark: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        },
+      },
+
+      {
+        histogram: "PLACES_DATABASE_FILESIZE_MB",
+        async callback() {
+          let placesDbPath = PathUtils.join(
+            PathUtils.profileDir,
+            "places.sqlite"
+          );
+          let info = await IOUtils.stat(placesDbPath);
+          return parseInt(info.size / BYTES_PER_MEBIBYTE);
+        },
+      },
+
+      {
+        histogram: "PLACES_DATABASE_FAVICONS_FILESIZE_MB",
+        async callback() {
+          let faviconsDbPath = PathUtils.join(
+            PathUtils.profileDir,
+            "favicons.sqlite"
+          );
+          let info = await IOUtils.stat(faviconsDbPath);
+          return parseInt(info.size / BYTES_PER_MEBIBYTE);
+        },
+      },
+
+      {
+        histogram: "PLACES_ANNOS_PAGES_COUNT",
+        query: "SELECT count(*) FROM moz_annos",
+      },
+
+      {
+        histogram: "PLACES_MAINTENANCE_DAYSFROMLAST",
+        callback() {
+          try {
+            let lastMaintenance = Services.prefs.getIntPref(
+              "places.database.lastMaintenance"
+            );
+            let nowSeconds = parseInt(Date.now() / 1000);
+            return parseInt((nowSeconds - lastMaintenance) / 86400);
+          } catch (ex) {
+            return 60;
+          }
+        },
+      },
+      {
+        scalar: "places.pages_need_frecency_recalculation",
+        query: "SELECT count(*) FROM moz_places WHERE recalc_frecency = 1",
+      },
+      {
+        scalar: "places.previousday_visits",
+        query: `SELECT COUNT(*) from moz_places
+                      WHERE hidden=0 AND last_visit_date < (strftime('%s', 'now', 'start of day') * 1000000)
+                      AND last_visit_date > (strftime('%s', 'now', 'start of day', '-1 day') * 1000000)
+                      AND last_visit_date IS NOT NULL;`,
+      },
+    ];
+
+    for (let probe of probes) {
+      let val;
+      if ("query" in probe) {
+        let db = await lazy.PlacesUtils.promiseDBConnection();
+        val = (
+          await db.execute(probe.query, probe.params || {})
+        )[0].getResultByIndex(0);
+      }
+      // Report the result of the probe through Telemetry.
+      // The resulting promise cannot reject.
+      if ("callback" in probe) {
+        val = await probe.callback(val);
+      }
+      probeValues[probe.histogram || probe.scalar] = val;
+      if (probe.histogram) {
+        Services.telemetry.getHistogramById(probe.histogram).add(val);
+      } else if (probe.scalar) {
+        Services.telemetry.scalarSet(probe.scalar, val);
+      } else {
+        throw new Error("Unknwon telemetry probe type");
+      }
+    }
+  },
+
+  /**
+   * Remove old and useless places.sqlite.corrupt files.
+   *
+   * @resolves to an array of logs for this task.
+   *
+   */
+  async removeOldCorruptDBs() {
+    let logs = [];
+    logs.push(
+      "> Cleanup profile from places.sqlite.corrupt files older than " +
+        CORRUPT_DB_RETAIN_DAYS +
+        " days."
+    );
+    let re = /places\.sqlite(-\d)?\.corrupt$/;
+    let currentTime = Date.now();
+    let children = await IOUtils.getChildren(PathUtils.profileDir);
+    try {
+      for (let entry of children) {
+        let fileInfo = await IOUtils.stat(entry);
+        let lastModificationDate;
+        if (fileInfo.type == "regular" && re.test(entry)) {
+          lastModificationDate = fileInfo.lastModified;
+          try {
+            // Convert milliseconds to days.
+            let days = Math.ceil(
+              (currentTime - lastModificationDate) / MS_PER_DAY
+            );
+            if (days >= CORRUPT_DB_RETAIN_DAYS || days < 0) {
+              await IOUtils.remove(entry);
+            }
+          } catch (error) {
+            logs.push("Could not remove file: " + entry, error);
+          }
+        }
+      }
+    } catch (error) {
+      logs.push("removeOldCorruptDBs failed", error);
+    }
+    return logs;
+  },
+
+  /**
+   * Gets detailed statistics about database entities like tables and indices.
+   * @returns {Map} a Map by table name, containing an object with the following
+   *          properties:
+   *            - efficiencyPerc: percentage filling of pages, an high
+   *              efficiency means most pages are filled up almost completely.
+   *              This value is not particularly useful with a low number of
+   *              pages.
+   *            - sizeBytes: size of the entity in bytes
+   *            - pages: number of pages of the entity
+   *            - sizePerc: percentage of the total database size
+   *            - sequentialityPerc: percentage of sequential pages, this is
+   *              a global value of the database, thus it's the same for every
+   *              entity, and it can be used to evaluate fragmentation and the
+   *              need for vacuum.
+   */
+  async getEntitiesStats() {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(`
+      /* do not warn (bug no): no need for index */
+      SELECT name,
+      round((pgsize - unused) * 100.0 / pgsize, 1) as efficiency_perc,
+      pgsize as size_bytes, pageno as pages,
+      round(pgsize * 100.0 / (SELECT sum(pgsize) FROM dbstat WHERE aggregate = TRUE), 1) as size_perc,
+      round((
+        WITH s(row, pageno) AS (
+          SELECT row_number() OVER (ORDER BY path), pageno FROM dbstat ORDER BY path
+        )
+        SELECT sum(s1.pageno+1==s2.pageno)*100.0/count(*)
+        FROM s AS s1, s AS s2
+        WHERE s1.row+1=s2.row
+      ), 1) AS sequentiality_perc
+      FROM dbstat
+      WHERE aggregate = TRUE
+    `);
+    let entitiesByName = new Map();
+    for (let row of rows) {
+      let details = {
+        efficiencyPerc: row.getResultByName("efficiency_perc"),
+        pages: row.getResultByName("pages"),
+        sizeBytes: row.getResultByName("size_bytes"),
+        sizePerc: row.getResultByName("size_perc"),
+        sequentialityPerc: row.getResultByName("sequentiality_perc"),
+      };
+      entitiesByName.set(row.getResultByName("name"), details);
+    }
+    return entitiesByName;
+  },
+
+  /**
+   * Gets detailed statistics about database entities and their respective row
+   * counts.
+   * @returns {Array} An array that augments each object returned by
+   *          {@link getEntitiesStats} with the following extra properties:
+   *            - entity: name of the entity
+   *            - count: row count of the entity
+   */
+  async getEntitiesStatsAndCounts() {
+    let stats = await PlacesDBUtils.getEntitiesStats();
+    let data = [];
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    for (let [entity, value] of stats) {
+      let count = "-";
+      try {
+        if (
+          entity.startsWith("moz_") &&
+          !entity.endsWith("index") &&
+          entity != "moz_places_visitcount" /* bug in index name */
+        ) {
+          count = (
+            await db.execute(`SELECT count(*) FROM ${entity}`)
+          )[0].getResultByIndex(0);
+        }
+      } catch (ex) {
+        console.error(ex);
+      }
+      data.push(Object.assign(value, { entity, count }));
+    }
+    return data;
+  },
+
+  /**
+   * Runs a list of tasks, returning a Map when done.
+   *
+   * @param tasks
+   *        Array of tasks to be executed, in form of pointers to methods in
+   *        this module.
+   * @return {Promise}
+   *        A promise that resolves with a Map[taskName(String) -> Object].
+   *        The Object has the following properties:
+   *         - succeeded: boolean
+   *         - logs: an array of strings containing the messages logged by the task
+   */
+  async runTasks(tasks) {
+    if (!this._registeredShutdownObserver) {
+      this._registeredShutdownObserver = true;
+      lazy.PlacesUtils.registerShutdownFunction(() => {
+        this._isShuttingDown = true;
+      });
+    }
+    PlacesDBUtils._clearTaskQueue = false;
+    let tasksMap = new Map();
+    for (let task of tasks) {
+      if (PlacesDBUtils._isShuttingDown) {
+        tasksMap.set(task.name, {
+          succeeded: false,
+          logs: ["Shutting down, will not schedule the task."],
+        });
+        continue;
+      }
+
+      if (PlacesDBUtils._clearTaskQueue) {
+        tasksMap.set(task.name, {
+          succeeded: false,
+          logs: ["The task queue was cleared by an error in another task."],
+        });
+        continue;
+      }
+
+      let result = await task()
+        .then((logs = [`${task.name} complete`]) => ({ succeeded: true, logs }))
+        .catch(err => ({ succeeded: false, logs: [err.message] }));
+      tasksMap.set(task.name, result);
+    }
+    return tasksMap;
+  },
+};
+
+async function integrity(dbName) {
+  async function check(db) {
+    let row;
+    await db.execute("PRAGMA integrity_check", null, (r, cancel) => {
+      row = r;
+      cancel();
+    });
+    return row.getResultByIndex(0) === "ok";
+  }
+
+  // Create a new connection for this check, so we can operate independently
+  // from a broken Places service.
+  // openConnection returns an exception with .result == Cr.NS_ERROR_FILE_CORRUPTED,
+  // we should do the same everywhere we want maintenance to try replacing the
+  // database on next startup.
+  let path = PathUtils.join(PathUtils.profileDir, dbName);
+  let db = await lazy.Sqlite.openConnection({ path });
+  try {
+    if (await check(db)) {
+      return;
+    }
+
+    // We stopped due to an integrity corruption, try to fix it if possible.
+    // First, try to reindex, this often fixes simple indices problems.
+    try {
+      await db.execute("REINDEX");
+    } catch (ex) {
+      throw new Components.Exception(
+        "Impossible to reindex database",
+        Cr.NS_ERROR_FILE_CORRUPTED
+      );
+    }
+
+    // Check again.
+    if (!(await check(db))) {
+      throw new Components.Exception(
+        "The database is still corrupt",
+        Cr.NS_ERROR_FILE_CORRUPTED
+      );
+    }
+  } finally {
+    await db.close();
+  }
+}
+
+export function PlacesDBUtilsIdleMaintenance() {}
+
+PlacesDBUtilsIdleMaintenance.prototype = {
+  observe(subject, topic, data) {
+    switch (topic) {
+      case "idle-daily":
+        // Once a week run places.sqlite maintenance tasks.
+        let lastMaintenance = Services.prefs.getIntPref(
+          "places.database.lastMaintenance",
+          0
+        );
+        let nowSeconds = parseInt(Date.now() / 1000);
+        if (lastMaintenance < nowSeconds - MAINTENANCE_INTERVAL_SECONDS) {
+          PlacesDBUtils.maintenanceOnIdle();
+        }
+        break;
+      default:
+        throw new Error("Trying to handle an unknown category.");
+    }
+  },
+  classID: Components.ID("d38926e0-29c1-11eb-8588-0800200c9a66"),
+  QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+};
diff --git a/toolkit/components/places/PlacesExpiration.sys.mjs b/toolkit/components/places/PlacesExpiration.sys.mjs
new file mode 100644
index 0000000000..4db494d63e
--- /dev/null
+++ b/toolkit/components/places/PlacesExpiration.sys.mjs
@@ -0,0 +1,957 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This component handles history and orphans expiration.
+ * Expiration runs:
+ * - At idle, but just once, we stop any other kind of expiration during idle
+ *   to preserve batteries in portable devices.
+ * - At shutdown, only if the database is dirty, we should still avoid to
+ *   expire too heavily on shutdown.
+ * - On a repeating timer we expire in small chunks.
+ *
+ * Expiration algorithm will adapt itself based on:
+ * - Memory size of the device.
+ * - Status of the database (clean or dirty).
+ */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+// Last expiration step should run before the final sync.
+const TOPIC_DEBUG_START_EXPIRATION = "places-debug-start-expiration";
+const TOPIC_IDLE_BEGIN = "idle";
+const TOPIC_IDLE_END = "active";
+const TOPIC_IDLE_DAILY = "idle-daily";
+const TOPIC_TESTING_MODE = "testing-mode";
+const TOPIC_TEST_INTERVAL_CHANGED = "test-interval-changed";
+
+// This value determines which systems we consider to have limited memory.
+// This is used to protect against large database sizes on those systems.
+const DATABASE_MEMORY_CONSTRAINED_THRESHOLD = 2147483648; // 2 GiB
+
+// This value determines which systems we consider to have limited disk space.
+// This is used to protect against large database sizes on those systems.
+const DATABASE_DISK_CONSTRAINED_THRESHOLD = 5368709120; // 5 GiB
+
+// Maximum size of the optimal database.  High-end hardware has plenty of
+// memory and disk space, but performances don't grow linearly.
+const DATABASE_MAX_SIZE = 78643200; // 75 MiB
+// If the physical memory size is bogus, fallback to this.
+const MEMSIZE_FALLBACK_BYTES = 268435456; // 256 MiB
+// If the disk available space is bogus, fallback to this.
+const DISKSIZE_FALLBACK_BYTES = 268435456; // 256 MiB
+
+// Max number of entries to expire at each expiration step.
+// This value is globally used for different kind of data we expire, can be
+// tweaked based on data type.  See below in getQuery.
+const EXPIRE_LIMIT_PER_STEP = 6;
+// When we run a large expiration step, the above limit is multiplied by this.
+const EXPIRE_LIMIT_PER_LARGE_STEP_MULTIPLIER = 10;
+
+// When history is clean or dirty enough we will adapt the expiration algorithm
+// to be more lazy or more aggressive.
+// This is done acting on the interval between expiration steps and the number
+// of expirable items.
+// 1. Clean history:
+//   We expire at (default interval * EXPIRE_AGGRESSIVITY_MULTIPLIER) the
+//   default number of entries.
+// 2. Dirty history:
+//   We expire at the default interval, but a greater number of entries
+//   (default number of entries * EXPIRE_AGGRESSIVITY_MULTIPLIER).
+const EXPIRE_AGGRESSIVITY_MULTIPLIER = 3;
+
+// This is the average size in bytes of an URI entry in the database.
+// Magic numbers are determined through analysis of the distribution of a ratio
+// between number of unique URIs and database size among our users.
+// Used as a fall back value when it's not possible to calculate the real value.
+const URIENTRY_AVG_SIZE = 700;
+
+// Seconds of idle time before starting a larger expiration step.
+// Notice during idle we stop the expiration timer since we don't want to hurt
+// stand-by or mobile devices batteries.
+const IDLE_TIMEOUT_SECONDS = 5 * 60;
+
+// If the number of pages over history limit is greater than this threshold,
+// expiration will be more aggressive, to bring back history to a saner size.
+const OVERLIMIT_PAGES_THRESHOLD = 1000;
+
+// Milliseconds in a day.
+const MSECS_PER_DAY = 86400000;
+
+// When we expire we can use these limits:
+// - SMALL for usual partial expirations, will expire a small chunk.
+// - LARGE for idle or shutdown expirations, will expire a large chunk.
+// - UNLIMITED will expire all the orphans.
+// - DEBUG will use a known limit, passed along with the debug notification.
+const LIMIT = {
+  SMALL: 0,
+  LARGE: 1,
+  UNLIMITED: 2,
+  DEBUG: 3,
+};
+
+// Represents the status of history database.
+const STATUS = {
+  CLEAN: 0,
+  DIRTY: 1,
+  UNKNOWN: 2,
+};
+
+// Represents actions on which a query will run.
+const ACTION = {
+  TIMED: 1 << 0, // happens every this.intervalSeconds
+  TIMED_OVERLIMIT: 1 << 1, // like TIMED but only when history is over limits
+  SHUTDOWN_DIRTY: 1 << 2, // happens at shutdown for DIRTY state
+  IDLE_DIRTY: 1 << 3, // happens on idle for DIRTY state
+  IDLE_DAILY: 1 << 4, // happens once a day on idle
+  DEBUG: 1 << 5, // happens on TOPIC_DEBUG_START_EXPIRATION
+};
+
+// The queries we use to expire.
+const EXPIRATION_QUERIES = {
+  // Some visits can be expired more often than others, cause they are less
+  // useful to the user and can pollute awesomebar results:
+  // 1. urls over 255 chars having only one visit
+  // 2. downloads
+  // 3. non-typed hidden single-visit urls
+  // We never expire redirect targets, because they are currently necessary to
+  // recognize redirect sources (see Bug 468710 for better options).
+  QUERY_FIND_EXOTIC_VISITS_TO_EXPIRE: {
+    sql: `INSERT INTO expiration_notify (v_id, url, guid, visit_date, reason)
+      WITH visits AS (
+        SELECT v.id, url, guid, visit_type, visit_date, visit_count, hidden, typed
+        FROM moz_historyvisits v
+        JOIN moz_places h ON h.id = v.place_id
+        WHERE visit_date < strftime('%s','now','localtime','start of day','-90 days','utc') * 1000000
+        AND visit_type NOT IN (5,6)
+      )
+      SELECT id, url, guid, visit_date, "exotic"
+      FROM visits
+      WHERE (hidden = 1 AND typed = 0 AND visit_count <= 1) OR visit_type = 7
+      UNION ALL
+      SELECT id, url, guid, visit_date, "exotic"
+      FROM visits
+      WHERE visit_count = 1 AND LENGTH(url) > 255
+      ORDER BY visit_date ASC
+      LIMIT :limit_visits`,
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Finds visits to be expired when history is over the unique pages limit,
+  // otherwise will return nothing.
+  // This explicitly excludes any visits added in the last 7 days, to protect
+  // users with thousands of bookmarks from constantly losing history.
+  QUERY_FIND_VISITS_TO_EXPIRE: {
+    sql: `INSERT INTO expiration_notify
+            (v_id, url, guid, visit_date, expected_results)
+          SELECT v.id, h.url, h.guid, v.visit_date, :limit_visits
+          FROM moz_historyvisits v
+          JOIN moz_places h ON h.id = v.place_id
+          WHERE (SELECT COUNT(*) FROM moz_places) > :max_uris
+          AND visit_date < strftime('%s','now','localtime','start of day','-7 days','utc') * 1000000
+          ORDER BY v.visit_date ASC
+          LIMIT :limit_visits`,
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Removes the previously found visits.
+  QUERY_EXPIRE_VISITS: {
+    sql: `DELETE FROM moz_historyvisits WHERE id IN (
+            SELECT v_id FROM expiration_notify WHERE v_id NOTNULL
+          )`,
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Finds orphan URIs in the database.
+  // Notice we won't notify single removed URIs on History.clear(), so we don't
+  // run this query in such a case, but just delete URIs.
+  // This could run in the middle of adding a visit or bookmark to a new page.
+  // In such a case since it is async, could end up expiring the orphan page
+  // before it actually gets the new visit or bookmark.
+  // Thus, since new pages get frecency -1, we filter on that.
+  QUERY_FIND_URIS_TO_EXPIRE: {
+    sql: `INSERT INTO expiration_notify (p_id, url, guid, visit_date)
+          SELECT h.id, h.url, h.guid, h.last_visit_date
+          FROM moz_places h
+          LEFT JOIN moz_historyvisits v ON h.id = v.place_id
+          WHERE h.last_visit_date IS NULL
+            AND h.foreign_count = 0
+            AND v.id IS NULL
+            AND frecency <> -1
+          LIMIT :limit_uris`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire found URIs from the database.
+  QUERY_EXPIRE_URIS: {
+    sql: `DELETE FROM moz_places WHERE id IN (
+            SELECT p_id FROM expiration_notify WHERE p_id NOTNULL
+          ) AND foreign_count = 0 AND last_visit_date ISNULL`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Hosts accumulated during the places delete are updated through a trigger
+  // (see nsPlacesTriggers.h).
+  QUERY_UPDATE_HOSTS: {
+    sql: `DELETE FROM moz_updateoriginsdelete_temp`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire from favicons any page that has only relations older than 180 days,
+  // if the page is not bookmarked, and we have a root icon that can be used
+  // as a placeholder until the page is visited again.
+  // The moz_pages_to_icons entries are removed by the table's FOREIGN KEY,
+  // while orphan icons are removed by the following queries.
+  QUERY_EXPIRE_OLD_FAVICONS: {
+    sql: `
+    DELETE FROM moz_pages_w_icons WHERE id IN (
+      WITH pages_with_old_relations (page_id, page_url_hash) AS (
+        SELECT page_id, page_url_hash
+        FROM moz_icons_to_pages ip
+        JOIN moz_pages_w_icons p ON p.id = page_id
+        GROUP BY page_id
+        HAVING max(expire_ms) < strftime('%s','now','localtime','start of day','-180 days','utc') * 1000
+      )
+      SELECT page_id
+      FROM pages_with_old_relations
+      JOIN moz_places h ON h.url_hash = page_url_hash
+      JOIN moz_origins o ON h.origin_id = o.id
+      WHERE foreign_count = 0
+      AND EXISTS (
+        SELECT 1 FROM moz_icons
+        WHERE root = 1
+          AND fixed_icon_url_hash = hash(fixup_url(o.host) || '/favicon.ico')
+      )
+      LIMIT 100
+    )`,
+    actions: ACTION.IDLE_DIRTY | ACTION.IDLE_DAILY | ACTION.DEBUG,
+  },
+
+  // Expire orphan pages from the icons database.
+  QUERY_EXPIRE_FAVICONS_PAGES: {
+    sql: `DELETE FROM moz_pages_w_icons
+          WHERE page_url_hash NOT IN (
+            SELECT url_hash FROM moz_places
+          ) OR NOT EXISTS (
+            SELECT 1 FROM moz_icons_to_pages WHERE page_id = moz_pages_w_icons.id
+          )`,
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire orphan icons from the database.
+  QUERY_EXPIRE_FAVICONS: {
+    sql: `DELETE FROM moz_icons WHERE id IN (
+            SELECT id FROM moz_icons WHERE root = 0
+            EXCEPT
+            SELECT icon_id FROM moz_icons_to_pages
+          )`,
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire orphan page annotations from the database.
+  QUERY_EXPIRE_ANNOS: {
+    sql: `DELETE FROM moz_annos WHERE id in (
+            SELECT a.id FROM moz_annos a
+            LEFT JOIN moz_places h ON a.place_id = h.id
+            WHERE h.id IS NULL
+            LIMIT :limit_annos
+          )`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire orphan inputhistory.
+  QUERY_EXPIRE_INPUTHISTORY: {
+    sql: `DELETE FROM moz_inputhistory
+          WHERE place_id IN (SELECT p_id FROM expiration_notify)
+          AND place_id IN (
+            SELECT i.place_id FROM moz_inputhistory i
+            LEFT JOIN moz_places h ON h.id = i.place_id
+            WHERE h.id IS NULL
+            LIMIT :limit_inputhistory
+          )`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Select entries for notifications.
+  // If p_id is set whole_entry = 1, then we have expired the full page.
+  // Either p_id or v_id are always set.
+  QUERY_SELECT_NOTIFICATIONS: {
+    sql: `/* do not warn (bug no): temp table has no index */
+          SELECT url, guid, MAX(visit_date) AS visit_date,
+                 MAX(IFNULL(MIN(p_id, 1), MIN(v_id, 0))) AS whole_entry,
+                 MAX(expected_results) AS expected_results,
+                 (SELECT MAX(visit_date) FROM expiration_notify
+                  WHERE reason = "expired" AND url = n.url AND p_id ISNULL
+                 ) AS most_recent_expired_visit
+          FROM expiration_notify n
+          GROUP BY url`,
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Empty the notifications table.
+  QUERY_DELETE_NOTIFICATIONS: {
+    sql: "DELETE FROM expiration_notify",
+    actions:
+      ACTION.TIMED |
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+
+  // Expire interactions older than N days.
+  QUERY_EXPIRE_INTERACTIONS: {
+    sql: `DELETE FROM moz_places_metadata
+          WHERE id IN (
+            SELECT id FROM moz_places_metadata
+            WHERE updated_at < strftime('%s','now','localtime','-' || :days_interactions || ' day','start of day','utc') * 1000
+            ORDER BY updated_at ASC
+            LIMIT :limit_interactions
+          )`,
+    get disabled() {
+      return !Services.prefs.getBoolPref(
+        "browser.places.interactions.enabled",
+        false
+      );
+    },
+    actions:
+      ACTION.TIMED_OVERLIMIT |
+      ACTION.SHUTDOWN_DIRTY |
+      ACTION.IDLE_DIRTY |
+      ACTION.IDLE_DAILY |
+      ACTION.DEBUG,
+  },
+};
+
+export function nsPlacesExpiration() {
+  // Allows other components to easily access getPagesLimit.
+  this.wrappedJSObject = this;
+
+  XPCOMUtils.defineLazyServiceGetter(
+    this,
+    "_idle",
+    "@mozilla.org/widget/useridleservice;1",
+    "nsIUserIdleService"
+  );
+
+  // Max number of unique URIs to retain in history.
+  // Notice this is a lazy limit.  This means we will start to expire if we will
+  // go over it, but we won't ensure that we will stop exactly when we reach it,
+  // instead we will stop after the next expiration step that will bring us
+  // below it.
+  // If this preference does not exist or has a negative value, we will
+  // calculate a limit based on current hardware.
+  XPCOMUtils.defineLazyPreferenceGetter(
+    this,
+    "maxPages",
+    "places.history.expiration.max_pages",
+    -1,
+    () => {
+      // Clear the cache.
+      dump("max_pages changing\n");
+      this._pagesLimit = null;
+    }
+  );
+
+  // Seconds between each expiration step.
+  XPCOMUtils.defineLazyPreferenceGetter(
+    this,
+    "intervalSeconds",
+    "places.history.expiration.interval_seconds",
+    3 * 60, // 3 minutes
+    () => {
+      // Renew the timer with the new interval value.
+      this._newTimer();
+    },
+    v => (v > 0 ? v : 3 * 60) // Accept only positive values.
+  );
+
+  this._dbInitializedPromise = lazy.PlacesUtils.withConnectionWrapper(
+    "PlacesExpiration.jsm: setup",
+    async db => {
+      await db.execute(
+        `CREATE TEMP TABLE expiration_notify (
+          id INTEGER PRIMARY KEY,
+          v_id INTEGER,
+          p_id INTEGER,
+          url TEXT NOT NULL,
+          guid TEXT NOT NULL,
+          visit_date INTEGER,
+          expected_results INTEGER NOT NULL DEFAULT 0,
+          reason TEXT NOT NULL DEFAULT "expired"
+        )`
+      );
+    }
+  )
+    .then(() => {
+      // Start the expiration timer.
+      this._newTimer();
+      // Expire daily on idle.
+      Services.obs.addObserver(this, TOPIC_IDLE_DAILY, true);
+    })
+    .catch(console.error);
+
+  // Block shutdown.
+  let shutdownClient =
+    lazy.PlacesUtils.history.connectionShutdownClient.jsclient;
+  shutdownClient.addBlocker("Places Expiration: shutdown", () => {
+    if (this._shuttingDown) {
+      return;
+    }
+    this._shuttingDown = true;
+    this.expireOnIdle = false;
+    if (this._timer) {
+      this._timer.cancel();
+      this._timer = null;
+    }
+    // If the database is dirty, we want to expire some entries, to speed up
+    // the expiration process.
+    if (this.status == STATUS.DIRTY) {
+      this._expire(ACTION.SHUTDOWN_DIRTY, LIMIT.LARGE).catch(console.error);
+    }
+  });
+}
+
+nsPlacesExpiration.prototype = {
+  observe(aSubject, aTopic, aData) {
+    if (this._shuttingDown) {
+      return;
+    }
+
+    if (aTopic == TOPIC_DEBUG_START_EXPIRATION) {
+      // The passed-in limit is the maximum number of visits to expire when
+      // history is over capacity.  Mind to correctly handle the NaN value.
+      let limit = parseInt(aData);
+      if (limit == -1) {
+        // Everything should be expired without any limit.  If history is over
+        // capacity then all existing visits will be expired.
+        // Should only be used in tests, since may cause dataloss.
+        this._expire(ACTION.DEBUG, LIMIT.UNLIMITED).catch(console.error);
+      } else if (limit > 0) {
+        // The number of expired visits is limited by this amount.  It may be
+        // used for testing purposes, like checking that limited queries work.
+        this._debugLimit = limit;
+        this._expire(ACTION.DEBUG, LIMIT.DEBUG).catch(console.error);
+      } else {
+        // Any other value is intended as a 0 limit, that means no visits
+        // will be expired.  Even if this doesn't touch visits, it will remove
+        // any orphan pages, icons, annotations and similar from the database,
+        // so it may be used for cleanup purposes.
+        this._debugLimit = -1;
+        this._expire(ACTION.DEBUG, LIMIT.DEBUG).catch(console.error);
+      }
+    } else if (aTopic == TOPIC_IDLE_BEGIN) {
+      // Stop the expiration timer.  We don't want to keep up expiring on idle
+      // to preserve batteries on mobile devices and avoid killing stand-by.
+      if (this._timer) {
+        this._timer.cancel();
+        this._timer = null;
+      }
+      if (this.expireOnIdle) {
+        this._expire(ACTION.IDLE_DIRTY, LIMIT.LARGE).catch(console.error);
+      }
+    } else if (aTopic == TOPIC_IDLE_END) {
+      // Restart the expiration timer.
+      if (!this._timer) {
+        this._newTimer();
+      }
+    } else if (aTopic == TOPIC_IDLE_DAILY) {
+      this._expire(ACTION.IDLE_DAILY, LIMIT.LARGE).catch(console.error);
+    } else if (aTopic == TOPIC_TESTING_MODE) {
+      this._testingMode = true;
+    } else if (aTopic == lazy.PlacesUtils.TOPIC_INIT_COMPLETE) {
+      const placesObserver = new PlacesWeakCallbackWrapper(
+        // History status is clean after a clear history.
+        () => {
+          this.status = STATUS.CLEAN;
+        }
+      );
+      PlacesObservers.addListener(["history-cleared"], placesObserver);
+    }
+  },
+
+  // nsINamed
+
+  name: "nsPlacesExpiration",
+
+  // nsITimerCallback
+
+  notify() {
+    // Run at the first idle, or after 5 minutes, whatever comes first.
+    Services.tm.idleDispatchToMainThread(async () => {
+      let db = await lazy.PlacesUtils.promiseDBConnection();
+      let pagesCount = (
+        await db.executeCached("SELECT count(*) AS count FROM moz_places")
+      )[0].getResultByName("count");
+      let pagesLimit = await this.getPagesLimit();
+      // Check if we are over history capacity, if so visits must be expired.
+      let overLimitPages = pagesCount - pagesLimit;
+      let action = overLimitPages > 0 ? ACTION.TIMED_OVERLIMIT : ACTION.TIMED;
+      // Adapt expiration aggressivity to the number of pages over the limit.
+      let limit =
+        overLimitPages > OVERLIMIT_PAGES_THRESHOLD ? LIMIT.LARGE : LIMIT.SMALL;
+      this._expire(action, limit).catch(console.error);
+    }, 300000);
+  },
+
+  _handleQueryResultAndAddNotification(row, notifications) {
+    // We don't want to notify after shutdown.
+    if (this._shuttingDown) {
+      return;
+    }
+
+    // expected_results is set to the number of expected visits by
+    // QUERY_FIND_VISITS_TO_EXPIRE.  We decrease that counter for each found
+    // visit and if it reaches zero we mark the database as dirty, since all
+    // the expected visits were expired, so it's likely the next run will
+    // find more.
+    let expectedResults = row.getResultByName("expected_results");
+    if (expectedResults > 0) {
+      if (!("_expectedResultsCount" in this)) {
+        this._expectedResultsCount = expectedResults;
+      }
+      if (this._expectedResultsCount > 0) {
+        this._expectedResultsCount--;
+      }
+    }
+
+    let uri = Services.io.newURI(row.getResultByName("url"));
+    let guid = row.getResultByName("guid");
+    let visitDate = row.getResultByName("visit_date");
+    let wholeEntry = row.getResultByName("whole_entry");
+    let mostRecentExpiredVisit = row.getResultByName(
+      "most_recent_expired_visit"
+    );
+
+    if (mostRecentExpiredVisit) {
+      let days = parseInt(
+        (Date.now() - mostRecentExpiredVisit / 1000) / MSECS_PER_DAY
+      );
+      if (!this._mostRecentExpiredVisitDays) {
+        this._mostRecentExpiredVisitDays = days;
+      } else if (days < this._mostRecentExpiredVisitDays) {
+        this._mostRecentExpiredVisitDays = days;
+      }
+    }
+
+    // Dispatch expiration notifications to history.
+    const isRemovedFromStore = !!wholeEntry;
+    notifications.push(
+      new PlacesVisitRemoved({
+        url: uri.spec,
+        pageGuid: guid,
+        reason: PlacesVisitRemoved.REASON_EXPIRED,
+        isRemovedFromStore,
+        isPartialVisistsRemoval: !isRemovedFromStore && visitDate > 0,
+      })
+    );
+  },
+
+  _shuttingDown: false,
+
+  _status: STATUS.UNKNOWN,
+  set status(aNewStatus) {
+    if (aNewStatus != this._status) {
+      // If status changes we should restart the timer.
+      this._status = aNewStatus;
+      this._newTimer();
+      // If needed add/remove the cleanup step on idle.  We want to expire on
+      // idle only if history is dirty, to preserve mobile devices batteries.
+      this.expireOnIdle = aNewStatus == STATUS.DIRTY;
+    }
+  },
+  get status() {
+    return this._status;
+  },
+
+  async getPagesLimit() {
+    if (this._pagesLimit != null) {
+      return this._pagesLimit;
+    }
+    if (this.maxPages >= 0) {
+      return (this._pagesLimit = this.maxPages);
+    }
+
+    // The user didn't specify a custom limit, so we calculate the number of
+    // unique places that may fit an optimal database size on this hardware.
+    // Oldest pages over this threshold will be expired.
+    let memSizeBytes = MEMSIZE_FALLBACK_BYTES;
+    try {
+      // Limit the size on systems with small memory.
+      memSizeBytes = Services.sysinfo.getProperty("memsize");
+    } catch (ex) {}
+    if (memSizeBytes <= 0) {
+      memSizeBytes = MEMSIZE_FALLBACK_BYTES;
+    }
+
+    let diskAvailableBytes = DISKSIZE_FALLBACK_BYTES;
+    try {
+      // Protect against a full disk or tiny quota.
+      diskAvailableBytes =
+        lazy.PlacesUtils.history.DBConnection.databaseFile.QueryInterface(
+          Ci.nsIFile
+        ).diskSpaceAvailable;
+    } catch (ex) {}
+    if (diskAvailableBytes <= 0) {
+      diskAvailableBytes = DISKSIZE_FALLBACK_BYTES;
+    }
+
+    const isMemoryConstrained =
+      memSizeBytes < DATABASE_MEMORY_CONSTRAINED_THRESHOLD;
+    const isDiskConstrained =
+      diskAvailableBytes < DATABASE_DISK_CONSTRAINED_THRESHOLD;
+
+    let optimalDatabaseSize = DATABASE_MAX_SIZE;
+    if (isMemoryConstrained || isDiskConstrained) {
+      // This size is used to protect against a large database size
+      // on disks with limited space or on systems with small memory
+      optimalDatabaseSize /= 2;
+    }
+
+    // Calculate avg size of a URI in the database.
+    let db;
+    try {
+      db = await lazy.PlacesUtils.promiseDBConnection();
+      if (db) {
+        let row = (
+          await db.execute(`SELECT * FROM pragma_page_size(),
+                                              pragma_page_count(),
+                                              pragma_freelist_count(),
+                                              (SELECT count(*) FROM moz_places)`)
+        )[0];
+        let pageSize = row.getResultByIndex(0);
+        let pageCount = row.getResultByIndex(1);
+        let freelistCount = row.getResultByIndex(2);
+        let uriCount = row.getResultByIndex(3);
+        let dbSize = (pageCount - freelistCount) * pageSize;
+        let avgURISize = Math.ceil(dbSize / uriCount);
+        // For new profiles this value may be too large, due to the Sqlite header,
+        // or Infinity when there are no pages.  Thus we must limit it.
+        if (avgURISize > URIENTRY_AVG_SIZE * 3) {
+          avgURISize = URIENTRY_AVG_SIZE;
+        }
+        return (this._pagesLimit = Math.ceil(optimalDatabaseSize / avgURISize));
+      }
+    } catch (ex) {
+      // We may have been initialized late in the shutdown process, maybe
+      // by a call to clear history on shutdown.
+      // If we're unable to get a connection clone, we'll just proceed with a
+      // large default value, it should not be critical at this point in the
+      // application life-cycle.
+    }
+    return (this._pagesLimit = 100000);
+  },
+
+  _isIdleObserver: false,
+  _expireOnIdle: false,
+  set expireOnIdle(aExpireOnIdle) {
+    // Observe idle regardless aExpireOnIdle, since we always want to stop
+    // timed expiration on idle, to preserve mobile battery life.
+    if (!this._isIdleObserver && !this._shuttingDown) {
+      this._idle.addIdleObserver(this, IDLE_TIMEOUT_SECONDS);
+      this._isIdleObserver = true;
+    } else if (this._isIdleObserver && this._shuttingDown) {
+      this._idle.removeIdleObserver(this, IDLE_TIMEOUT_SECONDS);
+      this._isIdleObserver = false;
+    }
+
+    // If running a debug expiration we need full control of what happens
+    // but idle cleanup could activate in the middle, since tinderboxes are
+    // permanently idle.  That would cause unexpected oranges, so disable it.
+    if (this._debugLimit !== undefined) {
+      this._expireOnIdle = false;
+    } else {
+      this._expireOnIdle = aExpireOnIdle;
+    }
+  },
+  get expireOnIdle() {
+    return this._expireOnIdle;
+  },
+
+  // Number of expiration steps needed to reach a CLEAN status.
+  _telemetrySteps: 1,
+
+  /**
+   * Expires visits and orphans.
+   *
+   * @param aAction
+   *        The ACTION we are expiring for.  See the ACTION const for values.
+   * @param aLimit
+   *        Whether to use small, large or no limits when expiring.  See the
+   *        LIMIT const for values.
+   */
+  async _expire(aAction, aLimit) {
+    // Don't try to further expire after shutdown.
+    if (this._shuttingDown && aAction != ACTION.SHUTDOWN_DIRTY) {
+      return;
+    }
+    await this._dbInitializedPromise;
+
+    try {
+      let notifications = [];
+      await lazy.PlacesUtils.withConnectionWrapper(
+        "PlacesExpiration.jsm: expire",
+        async db => {
+          await db.executeTransaction(async () => {
+            for (let queryType in EXPIRATION_QUERIES) {
+              let query = EXPIRATION_QUERIES[queryType];
+              if (query.actions & aAction && !query.disabled) {
+                let params = await this._getQueryParams(
+                  queryType,
+                  aLimit,
+                  aAction
+                );
+                await db.executeCached(query.sql, params, row => {
+                  this._handleQueryResultAndAddNotification(row, notifications);
+                });
+              }
+            }
+          });
+        }
+      );
+      if (notifications.length) {
+        PlacesObservers.notifyListeners(notifications);
+      }
+    } catch (ex) {
+      console.error(ex);
+      return;
+    }
+
+    if (this._mostRecentExpiredVisitDays) {
+      try {
+        Services.telemetry
+          .getHistogramById("PLACES_MOST_RECENT_EXPIRED_VISIT_DAYS")
+          .add(this._mostRecentExpiredVisitDays);
+      } catch (ex) {
+        console.error("Unable to report telemetry.");
+      } finally {
+        delete this._mostRecentExpiredVisitDays;
+      }
+    }
+
+    if ("_expectedResultsCount" in this) {
+      // Adapt the aggressivity of steps based on the status of history.
+      // A dirty history will return all the entries we are expecting bringing
+      // our countdown to zero, while a clean one will not.
+      let oldStatus = this.status;
+      this.status =
+        this._expectedResultsCount == 0 ? STATUS.DIRTY : STATUS.CLEAN;
+
+      // Collect or send telemetry data.
+      if (this.status == STATUS.DIRTY) {
+        this._telemetrySteps++;
+      } else {
+        // Avoid reporting the common cases where the database is clean, or
+        // a single step is needed.
+        if (oldStatus == STATUS.DIRTY) {
+          try {
+            Services.telemetry
+              .getHistogramById("PLACES_EXPIRATION_STEPS_TO_CLEAN2")
+              .add(this._telemetrySteps);
+          } catch (ex) {
+            console.error("Unable to report telemetry.");
+          }
+        }
+        this._telemetrySteps = 1;
+      }
+
+      delete this._expectedResultsCount;
+    }
+
+    // Dispatch a notification that expiration has finished.
+    Services.obs.notifyObservers(
+      null,
+      lazy.PlacesUtils.TOPIC_EXPIRATION_FINISHED
+    );
+  },
+
+  /**
+   * Generate a query used for expiration.
+   *
+   * @param aQueryType
+   *        Type of the query.
+   * @param aLimit
+   *        Whether to use small, large or no limits when expiring.  See the
+   *        LIMIT const for values.
+   * @param aAction
+   *        Current action causing the expiration.  See the ACTION const.
+   */
+  async _getQueryParams(aQueryType, aLimit, aAction) {
+    let baseLimit;
+    switch (aLimit) {
+      case LIMIT.UNLIMITED:
+        baseLimit = -1;
+        break;
+      case LIMIT.SMALL:
+        baseLimit = EXPIRE_LIMIT_PER_STEP;
+        break;
+      case LIMIT.LARGE:
+        baseLimit =
+          EXPIRE_LIMIT_PER_STEP * EXPIRE_LIMIT_PER_LARGE_STEP_MULTIPLIER;
+        break;
+      case LIMIT.DEBUG:
+        baseLimit = this._debugLimit;
+        break;
+    }
+    if (
+      this.status == STATUS.DIRTY &&
+      aAction != ACTION.DEBUG &&
+      baseLimit > 0
+    ) {
+      baseLimit *= EXPIRE_AGGRESSIVITY_MULTIPLIER;
+    }
+
+    switch (aQueryType) {
+      case "QUERY_FIND_EXOTIC_VISITS_TO_EXPIRE":
+        return {
+          // Avoid expiring all visits in case of an unlimited debug expiration,
+          // just remove orphans instead.
+          limit_visits:
+            aLimit == LIMIT.DEBUG && baseLimit == -1 ? 0 : baseLimit,
+        };
+      case "QUERY_FIND_VISITS_TO_EXPIRE":
+        return {
+          max_uris: await this.getPagesLimit(),
+          // Avoid expiring all visits in case of an unlimited debug expiration,
+          // just remove orphans instead.
+          limit_visits:
+            aLimit == LIMIT.DEBUG && baseLimit == -1 ? 0 : baseLimit,
+        };
+      case "QUERY_FIND_URIS_TO_EXPIRE":
+        return {
+          limit_uris: baseLimit,
+        };
+      case "QUERY_EXPIRE_ANNOS":
+        return {
+          // Each page may have multiple annos.
+          limit_annos: baseLimit * EXPIRE_AGGRESSIVITY_MULTIPLIER,
+        };
+      case "QUERY_EXPIRE_INPUTHISTORY":
+        return {
+          limit_inputhistory: baseLimit,
+        };
+      case "QUERY_EXPIRE_INTERACTIONS":
+        return {
+          days_interactions: Services.prefs.getIntPref(
+            "browser.places.interactions.expireDays",
+            60
+          ),
+          limit_interactions:
+            aLimit == LIMIT.DEBUG && baseLimit == -1 ? 0 : baseLimit,
+        };
+    }
+    return undefined;
+  },
+
+  /**
+   * Creates a new timer based on this.intervalSeconds.
+   *
+   * @return a REPEATING_SLACK nsITimer that runs every this.intervalSeconds.
+   */
+  _newTimer() {
+    if (this._timer) {
+      this._timer.cancel();
+    }
+    if (this._shuttingDown) {
+      return undefined;
+    }
+
+    if (!this._isIdleObserver) {
+      this._idle.addIdleObserver(this, IDLE_TIMEOUT_SECONDS);
+      this._isIdleObserver = true;
+    }
+
+    let interval =
+      this.status != STATUS.DIRTY
+        ? this.intervalSeconds * EXPIRE_AGGRESSIVITY_MULTIPLIER
+        : this.intervalSeconds;
+
+    let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+    timer.initWithCallback(
+      this,
+      interval * 1000,
+      Ci.nsITimer.TYPE_REPEATING_SLACK_LOW_PRIORITY
+    );
+    if (this._testingMode) {
+      Services.obs.notifyObservers(null, TOPIC_TEST_INTERVAL_CHANGED, interval);
+    }
+    return (this._timer = timer);
+  },
+
+  classID: Components.ID("705a423f-2f69-42f3-b9fe-1517e0dee56f"),
+
+  QueryInterface: ChromeUtils.generateQI([
+    "nsINamed",
+    "nsIObserver",
+    "nsISupportsWeakReference",
+    "nsITimerCallback",
+  ]),
+};
diff --git a/toolkit/components/places/PlacesFrecencyRecalculator.sys.mjs b/toolkit/components/places/PlacesFrecencyRecalculator.sys.mjs
new file mode 100644
index 0000000000..2de558af34
--- /dev/null
+++ b/toolkit/components/places/PlacesFrecencyRecalculator.sys.mjs
@@ -0,0 +1,593 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This component handles frecency recalculations and decay on idle.
+ */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+ChromeUtils.defineESModuleGetters(lazy, {
+  AsyncShutdown: "resource://gre/modules/AsyncShutdown.sys.mjs",
+  DeferredTask: "resource://gre/modules/DeferredTask.sys.mjs",
+  ObjectUtils: "resource://gre/modules/ObjectUtils.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "logger", function () {
+  return lazy.PlacesUtils.getLogger({ prefix: "FrecencyRecalculator" });
+});
+
+// Decay rate applied daily to frecency scores.
+// A scaling factor of .975 results in an half-life of 28 days.
+const FRECENCY_DECAYRATE = "0.975";
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "frecencyDecayRate",
+  "places.frecency.decayRate",
+  FRECENCY_DECAYRATE,
+  null,
+  val => {
+    if (typeof val == "string") {
+      val = parseFloat(val);
+    }
+    if (val > 1.0) {
+      lazy.logger.error("Invalid frecency decay rate value: " + val);
+      val = parseFloat(FRECENCY_DECAYRATE);
+    }
+    return val;
+  }
+);
+
+// An adaptive history entry is removed if unused for these many days.
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "adaptiveHistoryExpireDays",
+  "places.adaptiveHistory.expireDays",
+  90
+);
+
+// Time between deferred task executions.
+const DEFERRED_TASK_INTERVAL_MS = 2 * 60000;
+// Maximum time to wait for an idle before the task is executed anyway.
+const DEFERRED_TASK_MAX_IDLE_WAIT_MS = 5 * 60000;
+// Number of entries to update at once.
+const DEFAULT_CHUNK_SIZE = 50;
+
+export class PlacesFrecencyRecalculator {
+  classID = Components.ID("1141fd31-4c1a-48eb-8f1a-2f05fad94085");
+
+  /**
+   * A DeferredTask that runs our tasks.
+   */
+  #task = null;
+
+  /**
+   * Handler for alternative frecency.
+   * This allows to manager alternative ranking algorithms to experiment with.
+   */
+  #alternativeFrecencyHelper = null;
+
+  /**
+   * This is useful for testing.
+   */
+  get alternativeFrecencyInfo() {
+    return this.#alternativeFrecencyHelper?.sets;
+  }
+
+  constructor() {
+    lazy.logger.trace("Initializing Frecency Recalculator");
+
+    this.QueryInterface = ChromeUtils.generateQI([
+      "nsIObserver",
+      "nsISupportsWeakReference",
+    ]);
+
+    // Do not initialize during shutdown.
+    if (
+      Services.startup.isInOrBeyondShutdownPhase(
+        Ci.nsIAppStartup.SHUTDOWN_PHASE_APPSHUTDOWNTEARDOWN
+      )
+    ) {
+      return;
+    }
+
+    this.#task = new lazy.DeferredTask(
+      this.#taskFn.bind(this),
+      DEFERRED_TASK_INTERVAL_MS,
+      DEFERRED_TASK_MAX_IDLE_WAIT_MS
+    );
+    lazy.AsyncShutdown.profileChangeTeardown.addBlocker(
+      "PlacesFrecencyRecalculator: shutdown",
+      () => this.#finalize()
+    );
+
+    // The public methods and properties are intended to be used by tests, and
+    // are exposed through the raw js object. Since this is expected to work
+    // based on signals or notification, it should not be necessary to expose
+    // any API for the product, though if that would become necessary in the
+    // future, we could add an interface for the service.
+    this.wrappedJSObject = this;
+    // This can be used by tests to await for the decay process.
+    this.pendingFrecencyDecayPromise = Promise.resolve();
+
+    Services.obs.addObserver(this, "idle-daily", true);
+    Services.obs.addObserver(this, "frecency-recalculation-needed", true);
+
+    this.#alternativeFrecencyHelper = new AlternativeFrecencyHelper(this);
+
+    // Run once on startup, so we pick up any leftover work.
+    lazy.PlacesUtils.history.shouldStartFrecencyRecalculation = true;
+    this.maybeStartFrecencyRecalculation();
+  }
+
+  async #taskFn() {
+    if (this.#task.isFinalized) {
+      return;
+    }
+    const refObj = {};
+    const histogram = "PLACES_FRECENCY_RECALC_CHUNK_TIME_MS";
+    TelemetryStopwatch.start(histogram, refObj);
+    try {
+      if (await this.recalculateSomeFrecencies()) {
+        TelemetryStopwatch.finish(histogram, refObj);
+      } else {
+        TelemetryStopwatch.cancel(histogram, refObj);
+      }
+    } catch (ex) {
+      TelemetryStopwatch.cancel(histogram, refObj);
+      console.error(ex);
+      lazy.logger.error(ex);
+    }
+  }
+
+  #finalize() {
+    lazy.logger.trace("Finalizing frecency recalculator");
+    // We don't mind about tasks completiion, since we can execute them in the
+    // next session.
+    this.#task.disarm();
+    this.#task.finalize().catch(console.error);
+  }
+
+  /**
+   * Updates a chunk of outdated frecency values. If there's more frecency
+   * values to update at the end of the process, it may rearm the task.
+   * @param {Number} chunkSize maximum number of entries to update at a time,
+   *   set to -1 to update any entry.
+   * @resolves {boolean} Whether any entry was recalculated.
+   */
+  async recalculateSomeFrecencies({ chunkSize = DEFAULT_CHUNK_SIZE } = {}) {
+    lazy.logger.trace(
+      `Recalculate ${chunkSize >= 0 ? chunkSize : "infinite"} frecency values`
+    );
+    let affectedCount = 0;
+    let hasRecalculatedAnything = false;
+    let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+    await db.executeTransaction(async function () {
+      let affected = await db.executeCached(
+        `UPDATE moz_places
+        SET frecency = CALCULATE_FRECENCY(id)
+        WHERE id IN (
+          SELECT id FROM moz_places
+          WHERE recalc_frecency = 1
+          ORDER BY frecency DESC
+          LIMIT ${chunkSize}
+        )
+        RETURNING id`
+      );
+      affectedCount += affected.length;
+    });
+    let shouldRestartRecalculation = affectedCount >= chunkSize;
+    hasRecalculatedAnything = affectedCount > 0;
+    if (hasRecalculatedAnything) {
+      PlacesObservers.notifyListeners([new PlacesRanking()]);
+    }
+
+    // Also recalculate some origins frecency.
+    affectedCount = await this.#recalculateSomeOriginsFrecencies({
+      chunkSize,
+    });
+    shouldRestartRecalculation ||= affectedCount >= chunkSize;
+    hasRecalculatedAnything ||= affectedCount > 0;
+
+    // If alternative frecency is enabled, also recalculate a chunk of it.
+    affectedCount =
+      await this.#alternativeFrecencyHelper.recalculateSomeAlternativeFrecencies(
+        { chunkSize }
+      );
+    shouldRestartRecalculation ||= affectedCount >= chunkSize;
+    hasRecalculatedAnything ||= affectedCount > 0;
+
+    if (chunkSize > 0 && shouldRestartRecalculation) {
+      // There's more entries to recalculate, rearm the task.
+      this.#task.arm();
+    } else {
+      // There's nothing left to recalculate, wait for the next change.
+      lazy.PlacesUtils.history.shouldStartFrecencyRecalculation = false;
+      this.#task.disarm();
+    }
+    return hasRecalculatedAnything;
+  }
+
+  async #recalculateSomeOriginsFrecencies({ chunkSize }) {
+    lazy.logger.trace(`Recalculate ${chunkSize} origins frecency values`);
+    let affectedCount = 0;
+    let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+    await db.executeTransaction(async () => {
+      let affected = await db.executeCached(
+        `
+        UPDATE moz_origins
+        SET frecency = CAST(
+              (SELECT total(frecency)
+               FROM moz_places h
+               WHERE origin_id = moz_origins.id AND frecency > 0)
+              AS INT
+            ),
+            recalc_frecency = 0
+        WHERE id IN (
+          SELECT id FROM moz_origins
+          WHERE recalc_frecency = 1
+          ORDER BY frecency DESC
+          LIMIT ${chunkSize}
+        )
+        RETURNING id`
+      );
+      affectedCount += affected.length;
+
+      // Calculate and store the frecency statistics used to calculate a
+      // thredhold. Origins above that threshold will be considered meaningful
+      // and autofilled.
+      // While it may be tempting to do this only when some frecency was
+      // updated, that won't catch the edge case of the moz_origins table being
+      // emptied.
+      let row = (
+        await db.executeCached(`
+        SELECT count(*), total(frecency), total(pow(frecency,2))
+        FROM moz_origins
+        WHERE frecency > 0
+      `)
+      )[0];
+      await lazy.PlacesUtils.metadata.setMany(
+        new Map([
+          ["origin_frecency_count", row.getResultByIndex(0)],
+          ["origin_frecency_sum", row.getResultByIndex(1)],
+          ["origin_frecency_sum_of_squares", row.getResultByIndex(2)],
+        ])
+      );
+    });
+
+    return affectedCount;
+  }
+
+  /**
+   * Forces full recalculation of any outdated frecency values.
+   * This exists for testing purposes; in tests we don't want to wait for
+   * the deferred task to run, this can enforce a recalculation.
+   */
+  async recalculateAnyOutdatedFrecencies() {
+    this.#task.disarm();
+    return this.recalculateSomeFrecencies({ chunkSize: -1 });
+  }
+
+  /**
+   * Whether a recalculation task is pending.
+   */
+  get isRecalculationPending() {
+    return this.#task.isArmed;
+  }
+
+  /**
+   * Invoked periodically to eventually start a recalculation task.
+   */
+  maybeStartFrecencyRecalculation() {
+    if (
+      lazy.PlacesUtils.history.shouldStartFrecencyRecalculation &&
+      !this.#task.isFinalized
+    ) {
+      lazy.logger.trace("Arm frecency recalculation");
+      this.#task.arm();
+    }
+  }
+
+  /**
+   * Decays frecency and adaptive history.
+   * @resolves once the process is complete. Never rejects.
+   */
+  async decay() {
+    lazy.logger.trace("Decay frecency");
+    let refObj = {};
+    TelemetryStopwatch.start("PLACES_IDLE_FRECENCY_DECAY_TIME_MS", refObj);
+    // Ensure moz_places_afterupdate_frecency_trigger ignores decaying
+    // frecency changes.
+    lazy.PlacesUtils.history.isFrecencyDecaying = true;
+    try {
+      let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+      await db.executeTransaction(async function () {
+        // Decay all frecency rankings to reduce value of pages that haven't
+        // been visited in a while.
+        await db.executeCached(
+          `UPDATE moz_places SET frecency = ROUND(frecency * :decay_rate)
+            WHERE frecency > 0 AND recalc_frecency = 0`,
+          { decay_rate: lazy.frecencyDecayRate }
+        );
+        // Decay potentially unused adaptive entries (e.g. those that are at 1)
+        // to allow better chances for new entries that will start at 1.
+        await db.executeCached(
+          `UPDATE moz_inputhistory SET use_count = use_count * :decay_rate`,
+          { decay_rate: lazy.frecencyDecayRate }
+        );
+        // Delete any adaptive entries that won't help in ordering anymore.
+        await db.executeCached(
+          `DELETE FROM moz_inputhistory WHERE use_count < :use_count`,
+          {
+            use_count: Math.pow(
+              lazy.frecencyDecayRate,
+              lazy.adaptiveHistoryExpireDays
+            ),
+          }
+        );
+
+        TelemetryStopwatch.finish("PLACES_IDLE_FRECENCY_DECAY_TIME_MS", refObj);
+        PlacesObservers.notifyListeners([new PlacesRanking()]);
+      });
+    } catch (ex) {
+      TelemetryStopwatch.cancel("PLACES_IDLE_FRECENCY_DECAY_TIME_MS", refObj);
+      console.error(ex);
+      lazy.logger.error(ex);
+    } finally {
+      lazy.PlacesUtils.history.isFrecencyDecaying = false;
+    }
+  }
+
+  observe(subject, topic, data) {
+    lazy.logger.trace(`Got ${topic} topic`);
+    switch (topic) {
+      case "idle-daily":
+        this.pendingFrecencyDecayPromise = this.decay();
+        // Also recalculate frecencies.
+        lazy.logger.trace("Frecency recalculation on idle");
+        lazy.PlacesUtils.history.shouldStartFrecencyRecalculation = true;
+        this.maybeStartFrecencyRecalculation();
+        return;
+      case "frecency-recalculation-needed":
+        lazy.logger.trace("Frecency recalculation requested");
+        this.maybeStartFrecencyRecalculation();
+        return;
+      case "test-execute-taskFn":
+        subject.promise = this.#taskFn();
+        return;
+      case "test-alternative-frecency-init":
+        this.#alternativeFrecencyHelper = new AlternativeFrecencyHelper(this);
+        subject.promise =
+          this.#alternativeFrecencyHelper.initializedDeferred.promise;
+    }
+  }
+}
+
+class AlternativeFrecencyHelper {
+  initializedDeferred = Promise.withResolvers();
+  #recalculator = null;
+
+  sets = {
+    pages: {
+      // This pref is only read once and used to kick-off recalculations.
+      enabled: Services.prefs.getBoolPref(
+        "places.frecency.pages.alternative.featureGate",
+        false
+      ),
+      // Key used to store variables in the moz_meta table.
+      metadataKey: "page_alternative_frecency",
+      // The table containing frecency.
+      table: "moz_places",
+      // Object containing variables influencing the calculation.
+      // Any change to this object will cause a full recalculation on restart.
+      variables: {
+        // Current version of origins alternative frecency.
+        //  ! IMPORTANT: Always bump up when making changes to the algorithm.
+        version: 2,
+        highWeight: Services.prefs.getIntPref(
+          "places.frecency.pages.alternative.highWeight",
+          100
+        ),
+        mediumWeight: Services.prefs.getIntPref(
+          "places.frecency.pages.alternative.mediumWeight",
+          50
+        ),
+        lowWeight: Services.prefs.getIntPref(
+          "places.frecency.pages.alternative.lowWeight",
+          20
+        ),
+        halfLifeDays: Services.prefs.getIntPref(
+          "places.frecency.pages.alternative.halfLifeDays",
+          30
+        ),
+        numSampledVisits: Services.prefs.getIntPref(
+          "places.frecency.pages.alternative.numSampledVisits",
+          10
+        ),
+      },
+      method: this.#recalculateSomePagesAlternativeFrecencies,
+    },
+
+    origins: {
+      // This pref is only read once and used to kick-off recalculations.
+      enabled: Services.prefs.getBoolPref(
+        "places.frecency.origins.alternative.featureGate",
+        false
+      ),
+      // Key used to store variables in the moz_meta table.
+      metadataKey: "origin_alternative_frecency",
+      // The table containing frecency.
+      table: "moz_origins",
+      // Object containing variables influencing the calculation.
+      // Any change to this object will cause a full recalculation on restart.
+      variables: {
+        // Current version of origins alternative frecency.
+        //  ! IMPORTANT: Always bump up when making changes to the algorithm.
+        version: 2,
+        // Frecencies of pages are ignored after these many days.
+        daysCutOff: Services.prefs.getIntPref(
+          "places.frecency.origins.alternative.daysCutOff",
+          90
+        ),
+      },
+      method: this.#recalculateSomeOriginsAlternativeFrecencies,
+    },
+  };
+
+  constructor(recalculator) {
+    this.#recalculator = recalculator;
+    this.#kickOffAlternativeFrecencies()
+      .catch(console.error)
+      .finally(() => this.initializedDeferred.resolve());
+  }
+
+  async #kickOffAlternativeFrecencies() {
+    let recalculateFirstChunk = false;
+    for (let [type, set] of Object.entries(this.sets)) {
+      // Now check the variables cached in the moz_meta table. If not found we
+      // assume alternative frecency was disabled in the previous session.
+      let storedVariables = await lazy.PlacesUtils.metadata.get(
+        set.metadataKey,
+        null
+      );
+
+      // Check whether this is the first-run, that happens when the alternative
+      // ranking is enabled and it was not at the previous session, or variables
+      // were changed. We should recalculate all the alternative frecency values.
+      if (
+        set.enabled &&
+        !lazy.ObjectUtils.deepEqual(set.variables, storedVariables)
+      ) {
+        lazy.logger.trace(
+          `Alternative frecency of ${type} must be recalculated`
+        );
+        await lazy.PlacesUtils.withConnectionWrapper(
+          `PlacesFrecencyRecalculator :: ${type} alternative frecency set recalc`,
+          async db => {
+            await db.execute(`UPDATE ${set.table} SET recalc_alt_frecency = 1`);
+          }
+        );
+        await lazy.PlacesUtils.metadata.set(set.metadataKey, set.variables);
+        recalculateFirstChunk = true;
+        continue;
+      }
+
+      if (!set.enabled && storedVariables) {
+        lazy.logger.trace(`Clean up alternative frecency of ${type}`);
+        // Clear alternative frecency to save on space.
+        await lazy.PlacesUtils.withConnectionWrapper(
+          `PlacesFrecencyRecalculator :: ${type} alternative frecency set NULL`,
+          async db => {
+            await db.execute(`UPDATE ${set.table} SET alt_frecency = NULL`);
+          }
+        );
+        await lazy.PlacesUtils.metadata.delete(set.metadataKey);
+      }
+    }
+
+    if (recalculateFirstChunk) {
+      // Do a first recalculation immediately, so we don't leave the user
+      // with unranked entries for too long.
+      await this.recalculateSomeAlternativeFrecencies();
+
+      // Ensure the recalculation task is armed for a second run.
+      lazy.PlacesUtils.history.shouldStartFrecencyRecalculation = true;
+      this.#recalculator.maybeStartFrecencyRecalculation();
+    }
+  }
+
+  /**
+   * Updates a chunk of outdated frecency values.
+   * @param {Number} chunkSize maximum number of entries to update at a time,
+   *   set to -1 to update any entry.
+   * @resolves {Number} Number of affected pages.
+   */
+  async recalculateSomeAlternativeFrecencies({
+    chunkSize = DEFAULT_CHUNK_SIZE,
+  } = {}) {
+    let affected = 0;
+    for (let set of Object.values(this.sets)) {
+      if (!set.enabled) {
+        continue;
+      }
+      try {
+        affected += await set.method({ chunkSize, variables: set.variables });
+      } catch (ex) {
+        console.error(ex);
+      }
+    }
+    return affected;
+  }
+
+  async #recalculateSomePagesAlternativeFrecencies({ chunkSize, variables }) {
+    lazy.logger.trace(
+      `Recalculate ${chunkSize} alternative pages frecency values`
+    );
+    // Since it takes a long period of time to recalculate frecency of all the
+    // pages, due to the high number of them, we artificially increase the
+    // chunk size here.
+    let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+    let affected = await db.executeCached(
+      `UPDATE moz_places
+       SET alt_frecency = CALCULATE_ALT_FRECENCY(moz_places.id),
+           recalc_alt_frecency = 0
+       WHERE id IN (
+        SELECT id FROM moz_places
+          WHERE recalc_alt_frecency = 1
+          ORDER BY frecency DESC
+          LIMIT ${chunkSize * 2}
+      )
+      RETURNING id`
+    );
+    return affected;
+  }
+
+  async #recalculateSomeOriginsAlternativeFrecencies({ chunkSize, variables }) {
+    lazy.logger.trace(
+      `Recalculate ${chunkSize} alternative origins frecency values`
+    );
+    let affectedCount = 0;
+    let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+    await db.executeTransaction(async () => {
+      let affected = await db.executeCached(
+        `
+        UPDATE moz_origins
+        SET alt_frecency = (
+          SELECT sum(frecency)
+          FROM moz_places h
+          WHERE origin_id = moz_origins.id
+          AND last_visit_date >
+            strftime('%s','now','localtime','start of day',
+                     '-${variables.daysCutOff} day','utc') * 1000000
+        ), recalc_alt_frecency = 0
+        WHERE id IN (
+          SELECT id FROM moz_origins
+          WHERE recalc_alt_frecency = 1
+          ORDER BY frecency DESC
+          LIMIT ${chunkSize}
+        )
+        RETURNING id`
+      );
+      affectedCount += affected.length;
+
+      // Calculate and store the alternative frecency threshold. Origins above
+      // this threshold will be considered meaningful and autofilled.
+      if (affected.length) {
+        let threshold = (
+          await db.executeCached(`SELECT avg(alt_frecency) FROM moz_origins`)
+        )[0].getResultByIndex(0);
+        await lazy.PlacesUtils.metadata.set(
+          "origin_alt_frecency_threshold",
+          threshold
+        );
+      }
+    });
+
+    return affectedCount;
+  }
+}
diff --git a/toolkit/components/places/PlacesPreviews.sys.mjs b/toolkit/components/places/PlacesPreviews.sys.mjs
new file mode 100644
index 0000000000..08ee94664a
--- /dev/null
+++ b/toolkit/components/places/PlacesPreviews.sys.mjs
@@ -0,0 +1,449 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { EventEmitter } from "resource://gre/modules/EventEmitter.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  BackgroundPageThumbs: "resource://gre/modules/BackgroundPageThumbs.sys.mjs",
+  PageThumbsStorage: "resource://gre/modules/PageThumbs.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  clearTimeout: "resource://gre/modules/Timer.sys.mjs",
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "logConsole", function () {
+  return console.createInstance({
+    prefix: "PlacesPreviews",
+    maxLogLevel: Services.prefs.getBoolPref("places.previews.log", false)
+      ? "Debug"
+      : "Warn",
+  });
+});
+
+// Toggling Places previews requires a restart, because a database trigger
+// filling up tombstones is enabled on the database only when the pref is set
+// on startup.
+ChromeUtils.defineLazyGetter(lazy, "previewsEnabled", function () {
+  return Services.prefs.getBoolPref("places.previews.enabled", false);
+});
+
+// Preview deletions are done in chunks of this size.
+const DELETE_CHUNK_SIZE = 50;
+// This is the time between deletion chunks.
+const DELETE_TIMEOUT_MS = 60000;
+
+// The folder inside the profile folder where to store previews.
+const PREVIEWS_DIRECTORY = "places-previews";
+
+// How old a preview file should be before we replace it.
+const DAYS_BEFORE_REPLACEMENT = 30;
+
+/**
+ * This extends Set to only keep the latest 100 entries.
+ */
+class LimitedSet extends Set {
+  #limit = 100;
+  add(key) {
+    super.add(key);
+    let oversize = this.size - this.#limit;
+    if (oversize > 0) {
+      for (let entry of this) {
+        if (oversize-- <= 0) {
+          break;
+        }
+        this.delete(entry);
+      }
+    }
+  }
+}
+
+/**
+ * This class handles previews deletion from tombstones in the database.
+ * Deletion happens in chunks, each chunk runs after DELETE_TIMEOUT_MS, and
+ * the process is interrupted once there's nothing more to delete.
+ * Any page removal operations on the Places database will restart the timer.
+ */
+class DeletionHandler {
+  #timeoutId = null;
+  #shutdownProgress = {};
+
+  /**
+   * This can be set by tests to speed up the deletion process, otherwise the
+   * product should just use the default value.
+   */
+  #timeout = DELETE_TIMEOUT_MS;
+  get timeout() {
+    return this.#timeout;
+  }
+  set timeout(val) {
+    if (this.#timeoutId) {
+      lazy.clearTimeout(this.#timeoutId);
+      this.#timeoutId = null;
+    }
+    this.#timeout = val;
+    this.ensureRunning();
+  }
+
+  constructor() {
+    // Clear any pending timeouts on shutdown.
+    lazy.PlacesUtils.history.shutdownClient.jsclient.addBlocker(
+      "PlacesPreviews.jsm::DeletionHandler",
+      async () => {
+        this.#shutdownProgress.shuttingDown = true;
+        lazy.clearTimeout(this.#timeoutId);
+        this.#timeoutId = null;
+      },
+      { fetchState: () => this.#shutdownProgress }
+    );
+  }
+
+  /**
+   * This should be invoked everytime we expect there are tombstones to
+   * handle. If deletion is already pending, this is a no-op.
+   */
+  ensureRunning() {
+    if (this.#timeoutId || this.#shutdownProgress.shuttingDown) {
+      return;
+    }
+    this.#timeoutId = lazy.setTimeout(() => {
+      this.#timeoutId = null;
+      ChromeUtils.idleDispatch(() => {
+        this.#deleteChunk().catch(ex =>
+          lazy.logConsole.error("Error during previews deletion:" + ex)
+        );
+      });
+    }, this.timeout);
+  }
+
+  /**
+   * Deletes a chunk of previews.
+   */
+  async #deleteChunk() {
+    if (this.#shutdownProgress.shuttingDown) {
+      return;
+    }
+    // Select tombstones, delete images, then delete tombstones. This order
+    // ensures that in case of problems we'll try again in the future.
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let count;
+    let hashes = (
+      await db.executeCached(
+        `SELECT hash, (SELECT count(*) FROM moz_previews_tombstones) AS count
+         FROM moz_previews_tombstones LIMIT ${DELETE_CHUNK_SIZE}`
+      )
+    ).map(r => {
+      if (count === undefined) {
+        count = r.getResultByName("count");
+      }
+      return r.getResultByName("hash");
+    });
+    if (!count || this.#shutdownProgress.shuttingDown) {
+      // There's nothing to delete, or it's too late.
+      return;
+    }
+
+    let deleted = [];
+    for (let hash of hashes) {
+      let filePath = PlacesPreviews.getPathForHash(hash);
+      try {
+        await IOUtils.remove(filePath);
+        PlacesPreviews.onDelete(filePath);
+        deleted.push(hash);
+      } catch (ex) {
+        if (DOMException.isInstance(ex) && ex.name == "NotFoundError") {
+          deleted.push(hash);
+        } else {
+          lazy.logConsole.error("Unable to delete file: " + filePath);
+        }
+      }
+      if (this.#shutdownProgress.shuttingDown) {
+        return;
+      }
+    }
+    // Delete hashes from tombstones.
+    let params = deleted.reduce((p, c, i) => {
+      p["hash" + i] = c;
+      return p;
+    }, {});
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesPreviews.jsm::ExpirePreviews",
+      async db => {
+        await db.execute(
+          `DELETE FROM moz_previews_tombstones WHERE hash in
+            (${Object.keys(params)
+              .map(p => `:${p}`)
+              .join(",")})`,
+          params
+        );
+      }
+    );
+
+    if (count > DELETE_CHUNK_SIZE) {
+      this.ensureRunning();
+    }
+  }
+}
+
+/**
+ * Handles previews for Places urls.
+ * Previews are stored in WebP format, using MD5 hash of the page url in hex
+ * format. All the previews are saved into a "places-previews" folder under
+ * the roaming profile folder.
+ */
+export const PlacesPreviews = new (class extends EventEmitter {
+  #placesObserver = null;
+  #deletionHandler = null;
+  // This is used as a cache to avoid fetching the same preview multiple
+  // times in a short timeframe.
+  #recentlyUpdatedPreviews = new LimitedSet();
+
+  fileExtension = ".webp";
+  fileContentType = "image/webp";
+
+  constructor() {
+    super();
+    // Observe page removals and delete previews when necessary.
+    this.#placesObserver = new PlacesWeakCallbackWrapper(
+      this.handlePlacesEvents.bind(this)
+    );
+    PlacesObservers.addListener(
+      ["history-cleared", "page-removed"],
+      this.#placesObserver
+    );
+
+    // Start deletion in case it was interruped during the previous session,
+    // it will end once there's nothing more to delete.
+    this.#deletionHandler = new DeletionHandler();
+    this.#deletionHandler.ensureRunning();
+  }
+
+  handlePlacesEvents(events) {
+    for (const event of events) {
+      if (
+        event.type == "history-cleared" ||
+        (event.type == "page-removed" && event.isRemovedFromStore)
+      ) {
+        this.#deletionHandler.ensureRunning();
+        return;
+      }
+    }
+  }
+
+  /**
+   * Whether the feature is enabled. Use this instead of directly checking
+   * the pref, since it requires a restart.
+   */
+  get enabled() {
+    return lazy.previewsEnabled;
+  }
+
+  /**
+   * Returns the path to the previews folder.
+   * @returns {string} The path to the previews folder.
+   */
+  getPath() {
+    return PathUtils.join(
+      Services.dirsvc.get("ProfD", Ci.nsIFile).path,
+      PREVIEWS_DIRECTORY
+    );
+  }
+
+  /**
+   * Returns the file path of the preview for the given url.
+   * This doesn't guarantee the file exists.
+   * @param {string} url Address of the page.
+   * @returns {string} File path of the preview for the given url.
+   */
+  getPathForUrl(url) {
+    return PathUtils.join(
+      this.getPath(),
+      lazy.PlacesUtils.md5(url, { format: "hex" }) + this.fileExtension
+    );
+  }
+
+  /**
+   * Returns the file path of the preview having the given hash.
+   * @param {string} hash md5 hash in hex format.
+   * @returns {string } File path of the preview having the given hash.
+   */
+  getPathForHash(hash) {
+    return PathUtils.join(this.getPath(), hash + this.fileExtension);
+  }
+
+  /**
+   * Returns the moz-page-thumb: url to show the preview for the given url.
+   * @param {string} url Address of the page.
+   * @returns {string} Preview url for the given page url.
+   */
+  getPageThumbURL(url) {
+    return (
+      "moz-page-thumb://" +
+      "places-previews" +
+      "/?url=" +
+      encodeURIComponent(url) +
+      "&revision=" +
+      lazy.PageThumbsStorage.getRevision(url)
+    );
+  }
+
+  /**
+   * Updates the preview for the given page url. The update happens in
+   * background, using a windowless browser with very conservative privacy
+   * settings. Due to this, it may not look exactly like the page that the user
+   * is normally facing when logged in. See BackgroundPageThumbs.jsm for
+   * additional details.
+   * Unless `forceUpdate` is set, the preview is not updated if:
+   *  - It was already fetched recently
+   *  - The stored preview is younger than DAYS_BEFORE_REPLACEMENT
+   * The previem image is encoded using WebP.
+   * @param {string} url The address of the page.
+   * @param {boolean} [forceUpdate] Whether to update the preview regardless.
+   * @returns {boolean} Whether a preview is available and ready.
+   */
+  async update(url, { forceUpdate = false } = {}) {
+    if (!this.enabled) {
+      return false;
+    }
+    let filePath = this.getPathForUrl(url);
+    if (!forceUpdate) {
+      if (this.#recentlyUpdatedPreviews.has(filePath)) {
+        lazy.logConsole.debug("Skipping update because recently updated");
+        return true;
+      }
+      try {
+        let fileInfo = await IOUtils.stat(filePath);
+        if (
+          fileInfo.lastModified >
+          Date.now() - DAYS_BEFORE_REPLACEMENT * 86400000
+        ) {
+          // File is recent enough.
+          this.#recentlyUpdatedPreviews.add(filePath);
+          lazy.logConsole.debug("Skipping update because file is recent");
+          return true;
+        }
+      } catch (ex) {
+        // If the file doesn't exist, we always update it.
+        if (!DOMException.isInstance(ex) || ex.name != "NotFoundError") {
+          lazy.logConsole.error("Error while trying to stat() preview" + ex);
+          return false;
+        }
+      }
+    }
+
+    let buffer = await new Promise(resolve => {
+      let observer = (subject, topic, errorUrl) => {
+        if (errorUrl == url) {
+          resolve(null);
+        }
+      };
+      Services.obs.addObserver(observer, "page-thumbnail:error");
+      lazy.BackgroundPageThumbs.capture(url, {
+        dontStore: true,
+        contentType: this.fileContentType,
+        onDone: (url, reason, handle) => {
+          Services.obs.removeObserver(observer, "page-thumbnail:error");
+          resolve(handle?.data);
+        },
+      });
+    });
+    if (!buffer) {
+      lazy.logConsole.error("Unable to fetch preview: " + url);
+      return false;
+    }
+    try {
+      await IOUtils.makeDirectory(this.getPath(), { ignoreExisting: true });
+      await IOUtils.write(filePath, new Uint8Array(buffer), {
+        tmpPath: filePath + ".tmp",
+      });
+    } catch (ex) {
+      lazy.logConsole.error(
+        lazy.logConsole.error("Unable to create preview: " + ex)
+      );
+      return false;
+    }
+    this.#recentlyUpdatedPreviews.add(filePath);
+    return true;
+  }
+
+  /**
+   * Removes orphan previews that are not tracked by Places.
+   * Orphaning should normally not happen, but unexpected manipulation (e.g. the
+   * user touching the profile folder, or third party applications) could cause
+   * it.
+   * This method is slow, because it has to go through all the Places stored
+   * pages, thus it's suggested to only run it as periodic maintenance.
+   * @returns {boolean} Whether orphans deletion ran.
+   */
+  async deleteOrphans() {
+    if (!this.enabled) {
+      return false;
+    }
+
+    // From the previews directory, get all the files whose name matches our
+    // format.  Avoid any other filenames, also for safety reasons, since we are
+    // injecting them into SQL.
+    let files = await IOUtils.getChildren(this.getPath());
+    let hashes = files
+      .map(f => PathUtils.filename(f))
+      .filter(n => /^[a-f0-9]{32}\.webp$/)
+      .map(n => n.substring(0, n.lastIndexOf(".")));
+
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesPreviews.jsm::deleteOrphans",
+      async db => {
+        await db.execute(
+          `
+          WITH files(hash) AS (
+            VALUES ${hashes.map(h => `('${h}')`).join(", ")}
+          )
+          INSERT OR IGNORE INTO moz_previews_tombstones
+            SELECT hash FROM files
+            EXCEPT
+            SELECT md5hex(url) FROM moz_places
+          `
+        );
+      }
+    );
+    this.#deletionHandler.ensureRunning();
+    return true;
+  }
+
+  /**
+   * This is invoked by #deletionHandler every time a preview file is removed.
+   * @param {string} filePath The path of the deleted file.
+   */
+  onDelete(filePath) {
+    this.#recentlyUpdatedPreviews.delete(filePath);
+    this.emit("places-preview-deleted", filePath);
+  }
+
+  /**
+   * Used by tests to change the deletion timeout between chunks.
+   * @param {integer} timeout New timeout in milliseconds.
+   */
+  testSetDeletionTimeout(timeout) {
+    if (timeout === null) {
+      this.#deletionHandler.timeout = DELETE_TIMEOUT_MS;
+    } else {
+      this.#deletionHandler.timeout = timeout;
+    }
+  }
+})();
+
+/**
+ * Used to exposes nsIPlacesPreviewsHelperService to the moz-page-thumb protocol
+ * cpp implementation.
+ */
+export function PlacesPreviewsHelperService() {}
+
+PlacesPreviewsHelperService.prototype = {
+  classID: Components.ID("{bd0a4d3b-ff26-4d4d-9a62-a513e1c1bf92}"),
+  QueryInterface: ChromeUtils.generateQI(["nsIPlacesPreviewsHelperService"]),
+
+  getFilePathForURL(url) {
+    return PlacesPreviews.getPathForUrl(url);
+  },
+};
diff --git a/toolkit/components/places/PlacesQuery.sys.mjs b/toolkit/components/places/PlacesQuery.sys.mjs
new file mode 100644
index 0000000000..674e49b0ba
--- /dev/null
+++ b/toolkit/components/places/PlacesQuery.sys.mjs
@@ -0,0 +1,458 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  BinarySearch: "resource://gre/modules/BinarySearch.sys.mjs",
+  BrowserUtils: "resource://gre/modules/BrowserUtils.sys.mjs",
+  DeferredTask: "resource://gre/modules/DeferredTask.sys.mjs",
+  ObjectUtils: "resource://gre/modules/ObjectUtils.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+const BULK_PLACES_EVENTS_THRESHOLD = 50;
+const OBSERVER_DEBOUNCE_RATE_MS = 500;
+const OBSERVER_DEBOUNCE_TIMEOUT_MS = 5000;
+
+/**
+ * An object that contains details of a page visit.
+ *
+ * @typedef {object} HistoryVisit
+ *
+ * @property {Date} date
+ *   When this page was visited.
+ * @property {string} title
+ *   The page's title.
+ * @property {string} url
+ *   The page's URL.
+ */
+
+/**
+ * Cache key type depends on how visits are currently being grouped.
+ *
+ * By date: number - The start of day timestamp of the visit.
+ * By site: string - The domain name of the visit.
+ *
+ * @typedef {number | string} CacheKey
+ */
+
+/**
+ * Queries the places database using an async read only connection. Maintains
+ * an internal cache of query results which is live-updated by adding listeners
+ * to `PlacesObservers`. When the results are no longer needed, call `close` to
+ * remove the listeners.
+ */
+export class PlacesQuery {
+  /** @type {Map<CacheKey, HistoryVisit[]>} */
+  cachedHistory = null;
+  /** @type {object} */
+  cachedHistoryOptions = null;
+  /** @type {Map<string, Set<HistoryVisit>>} */
+  #cachedHistoryPerUrl = null;
+  /** @type {function(PlacesEvent[])} */
+  #historyListener = null;
+  /** @type {function(HistoryVisit[])} */
+  #historyListenerCallback = null;
+  /** @type {DeferredTask} */
+  #historyObserverTask = null;
+  #searchInProgress = false;
+
+  /**
+   * Get a snapshot of history visits at this moment.
+   *
+   * @param {object} [options]
+   *   Options to apply to the database query.
+   * @param {number} [options.daysOld]
+   *   The maximum number of days to go back in history.
+   * @param {number} [options.limit]
+   *   The maximum number of visits to return.
+   * @param {string} [options.sortBy]
+   *   The sorting order of history visits:
+   *   - "date": Group visits based on the date they occur.
+   *   - "site": Group visits based on host, excluding any "www." prefix.
+   * @returns {Map<any, HistoryVisit[]>}
+   *   History visits obtained from the database query.
+   */
+  async getHistory({ daysOld = 60, limit, sortBy = "date" } = {}) {
+    const options = { daysOld, limit, sortBy };
+    const cacheInvalid =
+      this.cachedHistory == null ||
+      !lazy.ObjectUtils.deepEqual(options, this.cachedHistoryOptions);
+    if (cacheInvalid) {
+      this.initializeCache(options);
+      await this.fetchHistory();
+    }
+    if (!this.#historyListener) {
+      this.#initHistoryListener();
+    }
+    return this.cachedHistory;
+  }
+
+  /**
+   * Clear existing cache and store options for the new query.
+   *
+   * @param {object} options
+   *   The database query options.
+   */
+  initializeCache(options = this.cachedHistoryOptions) {
+    this.cachedHistory = new Map();
+    this.cachedHistoryOptions = options;
+    this.#cachedHistoryPerUrl = new Map();
+  }
+
+  /**
+   * Run the database query and populate the history cache.
+   */
+  async fetchHistory() {
+    const { daysOld, limit, sortBy } = this.cachedHistoryOptions;
+    const db = await lazy.PlacesUtils.promiseDBConnection();
+    let groupBy;
+    switch (sortBy) {
+      case "date":
+        groupBy = "url, date(visit_date / 1000000, 'unixepoch', 'localtime')";
+        break;
+      case "site":
+        groupBy = "url";
+        break;
+    }
+    const sql = `SELECT MAX(visit_date) as visit_date, title, url
+      FROM moz_historyvisits v
+      JOIN moz_places h
+      ON v.place_id = h.id
+      WHERE visit_date >= (strftime('%s','now','localtime','start of day','-${Number(
+        daysOld
+      )} days','utc') * 1000000)
+      AND hidden = 0
+      GROUP BY ${groupBy}
+      ORDER BY visit_date DESC
+      LIMIT ${limit > 0 ? limit : -1}`;
+    const rows = await db.executeCached(sql);
+    for (const row of rows) {
+      const visit = this.formatRowAsVisit(row);
+      this.appendToCache(visit);
+    }
+  }
+
+  /**
+   * Search the database for visits matching a search query. This does not
+   * affect internal caches, and observers will not be notified of search
+   * results obtained from this query.
+   *
+   * @param {string} query
+   *   The search query.
+   * @param {number} [limit]
+   *   The maximum number of visits to return.
+   * @returns {HistoryVisit[]}
+   *   The matching visits.
+   */
+  async searchHistory(query, limit) {
+    const { sortBy } = this.cachedHistoryOptions;
+    const db = await lazy.PlacesUtils.promiseLargeCacheDBConnection();
+    let orderBy;
+    switch (sortBy) {
+      case "date":
+        orderBy = "visit_date DESC";
+        break;
+      case "site":
+        orderBy = "url";
+        break;
+    }
+    const sql = `SELECT MAX(visit_date) as visit_date, title, url
+      FROM moz_historyvisits v
+      JOIN moz_places h
+      ON v.place_id = h.id
+      WHERE AUTOCOMPLETE_MATCH(:query, url, title, NULL, 1, 1, 1, 1, :matchBehavior, :searchBehavior, NULL)
+      AND hidden = 0
+      GROUP BY url
+      ORDER BY ${orderBy}
+      LIMIT ${limit > 0 ? limit : -1}`;
+    if (this.#searchInProgress) {
+      db.interrupt();
+    }
+    try {
+      this.#searchInProgress = true;
+      const rows = await db.executeCached(sql, {
+        query,
+        matchBehavior: Ci.mozIPlacesAutoComplete.MATCH_ANYWHERE_UNMODIFIED,
+        searchBehavior: Ci.mozIPlacesAutoComplete.BEHAVIOR_HISTORY,
+      });
+      return rows.map(row => this.formatRowAsVisit(row));
+    } finally {
+      this.#searchInProgress = false;
+    }
+  }
+
+  /**
+   * Append a visit into the container it belongs to.
+   *
+   * @param {HistoryVisit} visit
+   *   The visit to append.
+   */
+  appendToCache(visit) {
+    this.#getContainerForVisit(visit).push(visit);
+    this.#insertIntoCachedHistoryPerUrl(visit);
+  }
+
+  /**
+   * Insert a visit into the container it belongs to, ensuring to maintain
+   * sorted order. Used for handling `page-visited` events after the initial
+   * fetch of history data.
+   *
+   * @param {HistoryVisit} visit
+   *   The visit to insert.
+   */
+  insertSortedIntoCache(visit) {
+    const container = this.#getContainerForVisit(visit);
+    const existingVisitsForUrl = this.#cachedHistoryPerUrl.get(visit.url) ?? [];
+    for (const existingVisit of existingVisitsForUrl) {
+      if (this.#getContainerForVisit(existingVisit) === container) {
+        if (existingVisit.date.getTime() >= visit.date.getTime()) {
+          // Existing visit is more recent. Don't insert this one.
+          return;
+        }
+        // Remove the existing visit, then insert the new one.
+        container.splice(container.indexOf(existingVisit), 1);
+        existingVisitsForUrl.delete(existingVisit);
+        break;
+      }
+    }
+    let insertionPoint = 0;
+    if (visit.date.getTime() < container[0]?.date.getTime()) {
+      insertionPoint = lazy.BinarySearch.insertionIndexOf(
+        (a, b) => b.date.getTime() - a.date.getTime(),
+        container,
+        visit
+      );
+    }
+    container.splice(insertionPoint, 0, visit);
+    this.#insertIntoCachedHistoryPerUrl(visit);
+  }
+
+  /**
+   * Insert a visit into the url-keyed history cache.
+   *
+   * @param {HistoryVisit} visit
+   *   The visit to insert.
+   */
+  #insertIntoCachedHistoryPerUrl(visit) {
+    const container = this.#cachedHistoryPerUrl.get(visit.url);
+    if (container) {
+      container.add(visit);
+    } else {
+      this.#cachedHistoryPerUrl.set(visit.url, new Set().add(visit));
+    }
+  }
+
+  /**
+   * Retrieve the corresponding container for this visit.
+   *
+   * @param {HistoryVisit} visit
+   *   The visit to check.
+   * @returns {HistoryVisit[]}
+   *   The container it belongs to.
+   */
+  #getContainerForVisit(visit) {
+    const mapKey = this.#getMapKeyForVisit(visit);
+    let container = this.cachedHistory?.get(mapKey);
+    if (!container) {
+      container = [];
+      this.cachedHistory?.set(mapKey, container);
+    }
+    return container;
+  }
+
+  #getMapKeyForVisit(visit) {
+    switch (this.cachedHistoryOptions.sortBy) {
+      case "date":
+        return this.getStartOfDayTimestamp(visit.date);
+      case "site":
+        const { protocol } = new URL(visit.url);
+        return protocol === "http:" || protocol === "https:"
+          ? lazy.BrowserUtils.formatURIStringForDisplay(visit.url)
+          : "";
+    }
+    return null;
+  }
+
+  /**
+   * Observe changes to the visits table. When changes are made, the callback
+   * is given the new list of visits. Only one callback can be active at a time
+   * (per instance). If one already exists, it will be replaced.
+   *
+   * @param {function(HistoryVisit[])} callback
+   *   The function to call when changes are made.
+   */
+  observeHistory(callback) {
+    this.#historyListenerCallback = callback;
+  }
+
+  /**
+   * Close this query. Caches are cleared and listeners are removed.
+   */
+  close() {
+    this.cachedHistory = null;
+    this.cachedHistoryOptions = null;
+    this.#cachedHistoryPerUrl = null;
+    if (this.#historyListener) {
+      PlacesObservers.removeListener(
+        [
+          "page-removed",
+          "page-visited",
+          "history-cleared",
+          "page-title-changed",
+        ],
+        this.#historyListener
+      );
+    }
+    this.#historyListener = null;
+    this.#historyListenerCallback = null;
+    if (!this.#historyObserverTask.isFinalized) {
+      this.#historyObserverTask.disarm();
+      this.#historyObserverTask.finalize();
+    }
+  }
+
+  /**
+   * Listen for changes to the visits table and update caches accordingly.
+   */
+  #initHistoryListener() {
+    this.#historyObserverTask = new lazy.DeferredTask(
+      async () => {
+        if (typeof this.#historyListenerCallback === "function") {
+          const history = await this.getHistory(this.cachedHistoryOptions);
+          this.#historyListenerCallback(history);
+        }
+      },
+      OBSERVER_DEBOUNCE_RATE_MS,
+      OBSERVER_DEBOUNCE_TIMEOUT_MS
+    );
+    this.#historyListener = async events => {
+      if (
+        events.length >= BULK_PLACES_EVENTS_THRESHOLD ||
+        events.some(({ type }) => type === "page-removed")
+      ) {
+        // Accounting for cascading deletes, or handling places events in bulk,
+        // can be expensive. In this case, we invalidate the cache once rather
+        // than handling each event individually.
+        this.cachedHistory = null;
+      } else if (this.cachedHistory != null) {
+        for (const event of events) {
+          switch (event.type) {
+            case "page-visited":
+              this.handlePageVisited(event);
+              break;
+            case "history-cleared":
+              this.initializeCache();
+              break;
+            case "page-title-changed":
+              this.handlePageTitleChanged(event);
+              break;
+          }
+        }
+      }
+      this.#historyObserverTask.arm();
+    };
+    PlacesObservers.addListener(
+      ["page-removed", "page-visited", "history-cleared", "page-title-changed"],
+      this.#historyListener
+    );
+  }
+
+  /**
+   * Handle a page visited event.
+   *
+   * @param {PlacesEvent} event
+   *   The event.
+   * @return {HistoryVisit}
+   *   The visit that was inserted, or `null` if no visit was inserted.
+   */
+  handlePageVisited(event) {
+    if (event.hidden) {
+      return null;
+    }
+    const visit = this.formatEventAsVisit(event);
+    this.insertSortedIntoCache(visit);
+    return visit;
+  }
+
+  /**
+   * Handle a page title changed event.
+   *
+   * @param {PlacesEvent} event
+   *   The event.
+   */
+  handlePageTitleChanged(event) {
+    const visits = this.#cachedHistoryPerUrl.get(event.url);
+    if (visits == null) {
+      return;
+    }
+    for (const visit of visits) {
+      visit.title = event.title;
+    }
+  }
+
+  /**
+   * Get timestamp from a date by only considering its year, month, and date
+   * (so that it can be used as a date-based key).
+   *
+   * @param {Date} date
+   *   The date to truncate.
+   * @returns {number}
+   *   The corresponding timestamp.
+   */
+  getStartOfDayTimestamp(date) {
+    return new Date(
+      date.getFullYear(),
+      date.getMonth(),
+      date.getDate()
+    ).getTime();
+  }
+
+  /**
+   * Get timestamp from a date by only considering its year and month (so that
+   * it can be used as a month-based key).
+   *
+   * @param {Date} date
+   *   The date to truncate.
+   * @returns {number}
+   *   The corresponding timestamp.
+   */
+  getStartOfMonthTimestamp(date) {
+    return new Date(date.getFullYear(), date.getMonth()).getTime();
+  }
+
+  /**
+   * Format a database row as a history visit.
+   *
+   * @param {mozIStorageRow} row
+   *   The row to format.
+   * @returns {HistoryVisit}
+   *   The resulting history visit.
+   */
+  formatRowAsVisit(row) {
+    return {
+      date: lazy.PlacesUtils.toDate(row.getResultByName("visit_date")),
+      title: row.getResultByName("title"),
+      url: row.getResultByName("url"),
+    };
+  }
+
+  /**
+   * Format a page visited event as a history visit.
+   *
+   * @param {PlacesEvent} event
+   *   The event to format.
+   * @returns {HistoryVisit}
+   *   The resulting history visit.
+   */
+  formatEventAsVisit(event) {
+    return {
+      date: new Date(event.visitTime),
+      title: event.lastKnownTitle,
+      url: event.url,
+    };
+  }
+}
diff --git a/toolkit/components/places/PlacesSyncUtils.sys.mjs b/toolkit/components/places/PlacesSyncUtils.sys.mjs
new file mode 100644
index 0000000000..6da1b91243
--- /dev/null
+++ b/toolkit/components/places/PlacesSyncUtils.sys.mjs
@@ -0,0 +1,2098 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Log: "resource://gre/modules/Log.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+/**
+ * This module exports functions for Sync to use when applying remote
+ * records. The calls are similar to those in `Bookmarks.jsm` and
+ * `nsINavBookmarksService`, with special handling for
+ * tags, keywords, synced annotations, and missing parents.
+ */
+export var PlacesSyncUtils = {};
+
+const { SOURCE_SYNC } = Ci.nsINavBookmarksService;
+
+const MICROSECONDS_PER_SECOND = 1000000;
+
+const MOBILE_BOOKMARKS_PREF = "browser.bookmarks.showMobileBookmarks";
+
+// These are defined as lazy getters to defer initializing the bookmarks
+// service until it's needed.
+ChromeUtils.defineLazyGetter(lazy, "ROOT_RECORD_ID_TO_GUID", () => ({
+  menu: lazy.PlacesUtils.bookmarks.menuGuid,
+  places: lazy.PlacesUtils.bookmarks.rootGuid,
+  tags: lazy.PlacesUtils.bookmarks.tagsGuid,
+  toolbar: lazy.PlacesUtils.bookmarks.toolbarGuid,
+  unfiled: lazy.PlacesUtils.bookmarks.unfiledGuid,
+  mobile: lazy.PlacesUtils.bookmarks.mobileGuid,
+}));
+
+ChromeUtils.defineLazyGetter(lazy, "ROOT_GUID_TO_RECORD_ID", () => ({
+  [lazy.PlacesUtils.bookmarks.menuGuid]: "menu",
+  [lazy.PlacesUtils.bookmarks.rootGuid]: "places",
+  [lazy.PlacesUtils.bookmarks.tagsGuid]: "tags",
+  [lazy.PlacesUtils.bookmarks.toolbarGuid]: "toolbar",
+  [lazy.PlacesUtils.bookmarks.unfiledGuid]: "unfiled",
+  [lazy.PlacesUtils.bookmarks.mobileGuid]: "mobile",
+}));
+
+ChromeUtils.defineLazyGetter(lazy, "ROOTS", () =>
+  Object.keys(lazy.ROOT_RECORD_ID_TO_GUID)
+);
+
+// Gets the history transition values we ignore and do not sync, as a
+// string, which is a comma-separated set of values - ie, something which can
+// be used with sqlite's IN operator. Does *not* includes the parens.
+ChromeUtils.defineLazyGetter(lazy, "IGNORED_TRANSITIONS_AS_SQL_LIST", () =>
+  // * We don't sync `TRANSITION_FRAMED_LINK` visits - these are excluded when
+  //   rendering the history menu, so we use the same constraints for Sync.
+  // * We don't sync `TRANSITION_DOWNLOAD` because it makes no sense to see
+  //   these on other devices - the downloaded file can not exist.
+  // * We don't want to sync TRANSITION_EMBED visits, but these aren't
+  //   stored in the DB, so no need to specify them.
+  // * 0 is invalid, and hopefully don't exist, but let's exclude it anyway.
+  // Array.toString() semantics are well defined and exactly what we need, so..
+  [
+    0,
+    lazy.PlacesUtils.history.TRANSITION_FRAMED_LINK,
+    lazy.PlacesUtils.history.TRANSITION_DOWNLOAD,
+  ].toString()
+);
+
+const HistorySyncUtils = (PlacesSyncUtils.history = Object.freeze({
+  SYNC_ID_META_KEY: "sync/history/syncId",
+  LAST_SYNC_META_KEY: "sync/history/lastSync",
+
+  /**
+   * Returns the current history sync ID, or `""` if one isn't set.
+   */
+  getSyncId() {
+    return lazy.PlacesUtils.metadata.get(HistorySyncUtils.SYNC_ID_META_KEY, "");
+  },
+
+  /**
+   * Assigns a new sync ID. This is called when we sync for the first time with
+   * a new account, and when we're the first to sync after a node reassignment.
+   *
+   * @return {Promise} resolved once the ID has been updated.
+   * @resolves to the new sync ID.
+   */
+  resetSyncId() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "HistorySyncUtils: resetSyncId",
+      function (db) {
+        let newSyncId = lazy.PlacesUtils.history.makeGuid();
+        return db.executeTransaction(async function () {
+          await setHistorySyncId(db, newSyncId);
+          return newSyncId;
+        });
+      }
+    );
+  },
+
+  /**
+   * Ensures that the existing local sync ID, if any, is up-to-date with the
+   * server. This is called when we sync with an existing account.
+   *
+   * @param newSyncId
+   *        The server's sync ID.
+   * @return {Promise} resolved once the ID has been updated.
+   */
+  async ensureCurrentSyncId(newSyncId) {
+    if (!newSyncId || typeof newSyncId != "string") {
+      throw new TypeError("Invalid new history sync ID");
+    }
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "HistorySyncUtils: ensureCurrentSyncId",
+      async function (db) {
+        let existingSyncId = await lazy.PlacesUtils.metadata.getWithConnection(
+          db,
+          HistorySyncUtils.SYNC_ID_META_KEY,
+          ""
+        );
+
+        if (existingSyncId == newSyncId) {
+          lazy.HistorySyncLog.trace("History sync ID up-to-date", {
+            existingSyncId,
+          });
+          return;
+        }
+
+        lazy.HistorySyncLog.info(
+          "History sync ID changed; resetting metadata",
+          {
+            existingSyncId,
+            newSyncId,
+          }
+        );
+        await db.executeTransaction(function () {
+          return setHistorySyncId(db, newSyncId);
+        });
+      }
+    );
+  },
+
+  /**
+   * Returns the last sync time, in seconds, for the history collection, or 0
+   * if history has never synced before.
+   */
+  async getLastSync() {
+    let lastSync = await lazy.PlacesUtils.metadata.get(
+      HistorySyncUtils.LAST_SYNC_META_KEY,
+      0
+    );
+    return lastSync / 1000;
+  },
+
+  /**
+   * Updates the history collection last sync time.
+   *
+   * @param lastSyncSeconds
+   *        The collection last sync time, in seconds, as a number or string.
+   */
+  async setLastSync(lastSyncSeconds) {
+    let lastSync = Math.floor(lastSyncSeconds * 1000);
+    if (!Number.isInteger(lastSync)) {
+      throw new TypeError("Invalid history last sync timestamp");
+    }
+    await lazy.PlacesUtils.metadata.set(
+      HistorySyncUtils.LAST_SYNC_META_KEY,
+      lastSync
+    );
+  },
+
+  /**
+   * Removes all history visits and pages from the database. Sync calls this
+   * method when it receives a command from a remote client to wipe all stored
+   * data.
+   *
+   * @return {Promise} resolved once all pages and visits have been removed.
+   */
+  async wipe() {
+    await lazy.PlacesUtils.history.clear();
+    await HistorySyncUtils.reset();
+  },
+
+  /**
+   * Removes the sync ID and last sync time for the history collection. Unlike
+   * `wipe`, this keeps all existing history pages and visits.
+   *
+   * @return {Promise} resolved once the metadata have been removed.
+   */
+  reset() {
+    return lazy.PlacesUtils.metadata.delete(
+      HistorySyncUtils.SYNC_ID_META_KEY,
+      HistorySyncUtils.LAST_SYNC_META_KEY
+    );
+  },
+
+  /**
+   * Clamps a history visit date between the current date and the earliest
+   * sensible date.
+   *
+   * @param {Date} visitDate
+   *        The visit date.
+   * @return {Date} The clamped visit date.
+   */
+  clampVisitDate(visitDate) {
+    let currentDate = new Date();
+    if (visitDate > currentDate) {
+      return currentDate;
+    }
+    if (visitDate < BookmarkSyncUtils.EARLIEST_BOOKMARK_TIMESTAMP) {
+      return new Date(BookmarkSyncUtils.EARLIEST_BOOKMARK_TIMESTAMP);
+    }
+    return visitDate;
+  },
+
+  /**
+   * Fetches the frecency for the URL provided
+   *
+   * @param url
+   * @returns {Number} The frecency of the given url
+   */
+  async fetchURLFrecency(url) {
+    let canonicalURL = lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.url(url);
+
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `
+      SELECT frecency
+      FROM moz_places
+      WHERE url_hash = hash(:url) AND url = :url
+      LIMIT 1`,
+      { url: canonicalURL.href }
+    );
+
+    return rows.length ? rows[0].getResultByName("frecency") : -1;
+  },
+
+  /**
+   * Filters syncable places from a collection of places guids.
+   *
+   * @param guids
+   *
+   * @returns {Array} new Array with the guids that aren't syncable
+   */
+  async determineNonSyncableGuids(guids) {
+    // Filter out hidden pages and transitions that we don't sync.
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let nonSyncableGuids = [];
+    for (let chunk of lazy.PlacesUtils.chunkArray(guids, db.variableLimit)) {
+      let rows = await db.execute(
+        `
+        SELECT DISTINCT p.guid FROM moz_places p
+        JOIN moz_historyvisits v ON p.id = v.place_id
+        WHERE p.guid IN (${new Array(chunk.length).fill("?").join(",")}) AND
+            (p.hidden = 1 OR v.visit_type IN (${
+              lazy.IGNORED_TRANSITIONS_AS_SQL_LIST
+            }))
+      `,
+        chunk
+      );
+      nonSyncableGuids = nonSyncableGuids.concat(
+        rows.map(row => row.getResultByName("guid"))
+      );
+    }
+    return nonSyncableGuids;
+  },
+
+  /**
+   * Change the guid of the given uri
+   *
+   * @param uri
+   * @param guid
+   */
+  changeGuid(uri, guid) {
+    let canonicalURL = lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.url(uri);
+    let validatedGuid = lazy.PlacesUtils.BOOKMARK_VALIDATORS.guid(guid);
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesSyncUtils.history: changeGuid",
+      async function (db) {
+        await db.executeCached(
+          `
+            UPDATE moz_places
+            SET guid = :guid
+            WHERE url_hash = hash(:page_url) AND url = :page_url`,
+          { guid: validatedGuid, page_url: canonicalURL.href }
+        );
+      }
+    );
+  },
+
+  /**
+   * Fetch the last 20 visits (date and type of it) corresponding to a given url
+   *
+   * @param url
+   * @returns {Array} Each element of the Array is an object with members: date and type
+   */
+  async fetchVisitsForURL(url) {
+    let canonicalURL = lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.url(url);
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `
+      SELECT visit_type type, visit_date date,
+      json_extract(e.sync_json, '$.unknown_sync_fields') as unknownSyncFields
+      FROM moz_historyvisits v
+      JOIN moz_places h ON h.id = v.place_id
+      LEFT OUTER JOIN moz_historyvisits_extra e ON e.visit_id = v.id
+      WHERE url_hash = hash(:url) AND url = :url
+      ORDER BY date DESC LIMIT 20`,
+      { url: canonicalURL.href }
+    );
+    return rows.map(row => {
+      let visitDate = row.getResultByName("date");
+      let visitType = row.getResultByName("type");
+      let visit = { date: visitDate, type: visitType };
+
+      // We should grab unknown fields to roundtrip them
+      // back to the server
+      let unknownFields = row.getResultByName("unknownSyncFields");
+      if (unknownFields) {
+        let unknownFieldsObj = JSON.parse(unknownFields);
+        for (const key in unknownFieldsObj) {
+          // We have to manually add it to the cleartext since that's
+          // what gets processed during upload
+          visit[key] = unknownFieldsObj[key];
+        }
+      }
+      return visit;
+    });
+  },
+
+  /**
+   * Fetches the guid of a uri
+   *
+   * @param uri
+   * @returns {String} The guid of the given uri
+   */
+  async fetchGuidForURL(url) {
+    let canonicalURL = lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.url(url);
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `
+        SELECT guid
+        FROM moz_places
+        WHERE url_hash = hash(:page_url) AND url = :page_url`,
+      { page_url: canonicalURL.href }
+    );
+    if (!rows.length) {
+      return null;
+    }
+    return rows[0].getResultByName("guid");
+  },
+
+  /**
+   * Fetch information about a guid (url, title and frecency)
+   *
+   * @param guid
+   * @returns {Object} Object with three members: url, title and frecency of the given guid
+   */
+  async fetchURLInfoForGuid(guid) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `
+      SELECT url, IFNULL(title, '') AS title, frecency,
+      json_extract(e.sync_json, '$.unknown_sync_fields') as unknownSyncFields
+      FROM moz_places h
+      LEFT OUTER JOIN moz_places_extra e ON e.place_id = h.id
+      WHERE guid = :guid`,
+      { guid }
+    );
+    if (rows.length === 0) {
+      return null;
+    }
+
+    let info = {
+      url: rows[0].getResultByName("url"),
+      title: rows[0].getResultByName("title"),
+      frecency: rows[0].getResultByName("frecency"),
+    };
+    let unknownFields = rows[0].getResultByName("unknownSyncFields");
+    if (unknownFields) {
+      // This will be unfurled at the caller since the
+      // cleartext process will drop this
+      info.unknownFields = unknownFields;
+    }
+    return info;
+  },
+
+  /**
+   * Get all URLs filtered by the limit and since members of the options object.
+   *
+   * @param options
+   *        Options object with two members, since and limit. Both of them must be provided
+   * @returns {Array} - Up to limit number of URLs starting from the date provided by since
+   *
+   * Note that some visit types are explicitly excluded - downloads and framed
+   * links.
+   */
+  async getAllURLs(options) {
+    // Check that the limit property is finite number.
+    if (!Number.isFinite(options.limit)) {
+      throw new Error("The number provided in options.limit is not finite.");
+    }
+    // Check that the since property is of type Date.
+    if (
+      !options.since ||
+      Object.prototype.toString.call(options.since) != "[object Date]"
+    ) {
+      throw new Error(
+        "The property since of the options object must be of type Date."
+      );
+    }
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let sinceInMicroseconds = lazy.PlacesUtils.toPRTime(options.since);
+    let rows = await db.executeCached(
+      `
+      SELECT DISTINCT p.url
+      FROM moz_places p
+      JOIN moz_historyvisits v ON p.id = v.place_id
+      WHERE p.last_visit_date > :cutoff_date AND
+            p.hidden = 0 AND
+            v.visit_type NOT IN (${lazy.IGNORED_TRANSITIONS_AS_SQL_LIST})
+      ORDER BY frecency DESC
+      LIMIT :max_results`,
+      { cutoff_date: sinceInMicroseconds, max_results: options.limit }
+    );
+    return rows.map(row => row.getResultByName("url"));
+  },
+  /**
+   * Insert or update the unknownFields that this client doesn't understand (yet)
+   * but stores & roundtrips them to prevent other clients from losing that data
+   *
+   * @param updates array of objects
+   *  an update object needs to have either a:
+   *  placeId: if we're putting unknownFields for a moz_places item
+   *  visitId: if we're putting unknownFields for a moz_historyvisits item
+   *  Note: Supplying none or both will result in that record being ignored
+   *  unknownFields: the stringified json to insert
+   */
+  async updateUnknownFieldsBatch(updates) {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "HistorySyncUtils: updateUnknownFieldsBatch",
+      async function (db) {
+        await db.executeTransaction(async () => {
+          for await (const update of updates) {
+            // Validate we only have one of these props
+            if (
+              (update.placeId && update.visitId) ||
+              (!update.placeId && !update.visitId)
+            ) {
+              continue;
+            }
+            let tableName = update.placeId
+              ? "moz_places_extra"
+              : "moz_historyvisits_extra";
+            let keyName = update.placeId ? "place_id" : "visit_id";
+            await db.executeCached(
+              `
+            INSERT INTO ${tableName} (${keyName}, sync_json)
+            VALUES (
+              :keyValue,
+              json_object('unknown_sync_fields', :unknownFields)
+            )
+            ON CONFLICT(${keyName}) DO UPDATE SET
+            sync_json=json_patch(${tableName}.sync_json, json_object('unknown_sync_fields',:unknownFields))
+            `,
+              {
+                keyValue: update.placeId ?? update.visitId,
+                unknownFields: update.unknownFields,
+              }
+            );
+          }
+        });
+      }
+    );
+  },
+  // End of history freeze
+}));
+
+const BookmarkSyncUtils = (PlacesSyncUtils.bookmarks = Object.freeze({
+  SYNC_ID_META_KEY: "sync/bookmarks/syncId",
+  LAST_SYNC_META_KEY: "sync/bookmarks/lastSync",
+  WIPE_REMOTE_META_KEY: "sync/bookmarks/wipeRemote",
+
+  // Jan 23, 1993 in milliseconds since 1970. Corresponds roughly to the release
+  // of the original NCSA Mosiac. We can safely assume that any dates before
+  // this time are invalid.
+  EARLIEST_BOOKMARK_TIMESTAMP: Date.UTC(1993, 0, 23),
+
+  KINDS: {
+    BOOKMARK: "bookmark",
+    QUERY: "query",
+    FOLDER: "folder",
+    LIVEMARK: "livemark",
+    SEPARATOR: "separator",
+  },
+
+  get ROOTS() {
+    return lazy.ROOTS;
+  },
+
+  /**
+   * Returns the current bookmarks sync ID, or `""` if one isn't set.
+   */
+  getSyncId() {
+    return lazy.PlacesUtils.metadata.get(
+      BookmarkSyncUtils.SYNC_ID_META_KEY,
+      ""
+    );
+  },
+
+  /**
+   * Indicates if the bookmarks engine should erase all bookmarks on the server
+   * and all other clients, because the user manually restored their bookmarks
+   * from a backup on this client.
+   */
+  async shouldWipeRemote() {
+    let shouldWipeRemote = await lazy.PlacesUtils.metadata.get(
+      BookmarkSyncUtils.WIPE_REMOTE_META_KEY,
+      false
+    );
+    return !!shouldWipeRemote;
+  },
+
+  /**
+   * Assigns a new sync ID, bumps the change counter, and flags all items as
+   * "NEW" for upload. This is called when we sync for the first time with a
+   * new account, when we're the first to sync after a node reassignment, and
+   * on the first sync after a manual restore.
+   *
+   * @return {Promise} resolved once the ID and all items have been updated.
+   * @resolves to the new sync ID.
+   */
+  resetSyncId() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: resetSyncId",
+      function (db) {
+        let newSyncId = lazy.PlacesUtils.history.makeGuid();
+        return db.executeTransaction(async function () {
+          await setBookmarksSyncId(db, newSyncId);
+          await resetAllSyncStatuses(
+            db,
+            lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW
+          );
+          return newSyncId;
+        });
+      }
+    );
+  },
+
+  /**
+   * Ensures that the existing local sync ID, if any, is up-to-date with the
+   * server. This is called when we sync with an existing account.
+   *
+   * We always take the server's sync ID. If we don't have an existing ID,
+   * we're either syncing for the first time with an existing account, or Places
+   * has automatically restored from a backup. If the sync IDs don't match,
+   * we're likely syncing after a node reassignment, where another client
+   * uploaded their bookmarks first.
+   *
+   * @param newSyncId
+   *        The server's sync ID.
+   * @return {Promise} resolved once the ID and all items have been updated.
+   */
+  async ensureCurrentSyncId(newSyncId) {
+    if (!newSyncId || typeof newSyncId != "string") {
+      throw new TypeError("Invalid new bookmarks sync ID");
+    }
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: ensureCurrentSyncId",
+      async function (db) {
+        let existingSyncId = await lazy.PlacesUtils.metadata.getWithConnection(
+          db,
+          BookmarkSyncUtils.SYNC_ID_META_KEY,
+          ""
+        );
+
+        // If we don't have a sync ID, take the server's without resetting
+        // sync statuses.
+        if (!existingSyncId) {
+          lazy.BookmarkSyncLog.info("Taking new bookmarks sync ID", {
+            newSyncId,
+          });
+          await db.executeTransaction(() => setBookmarksSyncId(db, newSyncId));
+          return;
+        }
+
+        // If the existing sync ID matches the server, great!
+        if (existingSyncId == newSyncId) {
+          lazy.BookmarkSyncLog.trace("Bookmarks sync ID up-to-date", {
+            existingSyncId,
+          });
+          return;
+        }
+
+        // Otherwise, we have a sync ID, but it doesn't match, so we were likely
+        // node reassigned. Take the server's sync ID and reset all items to
+        // "UNKNOWN" so that we can merge.
+        lazy.BookmarkSyncLog.info(
+          "Bookmarks sync ID changed; resetting sync statuses",
+          { existingSyncId, newSyncId }
+        );
+        await db.executeTransaction(async function () {
+          await setBookmarksSyncId(db, newSyncId);
+          await resetAllSyncStatuses(
+            db,
+            lazy.PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN
+          );
+        });
+      }
+    );
+  },
+
+  /**
+   * Returns the last sync time, in seconds, for the bookmarks collection, or 0
+   * if bookmarks have never synced before.
+   */
+  async getLastSync() {
+    let lastSync = await lazy.PlacesUtils.metadata.get(
+      BookmarkSyncUtils.LAST_SYNC_META_KEY,
+      0
+    );
+    return lastSync / 1000;
+  },
+
+  /**
+   * Updates the bookmarks collection last sync time.
+   *
+   * @param lastSyncSeconds
+   *        The collection last sync time, in seconds, as a number or string.
+   */
+  async setLastSync(lastSyncSeconds) {
+    let lastSync = Math.floor(lastSyncSeconds * 1000);
+    if (!Number.isInteger(lastSync)) {
+      throw new TypeError("Invalid bookmarks last sync timestamp");
+    }
+    await lazy.PlacesUtils.metadata.set(
+      BookmarkSyncUtils.LAST_SYNC_META_KEY,
+      lastSync
+    );
+  },
+
+  /**
+   * Resets Sync metadata for bookmarks in Places. This function behaves
+   * differently depending on the change source, and may be called from
+   * `PlacesSyncUtils.bookmarks.reset` or
+   * `PlacesUtils.bookmarks.eraseEverything`.
+   *
+   * - RESTORE: The user is restoring from a backup. Drop the sync ID, last
+   *   sync time, and tombstones; reset sync statuses for remaining items to
+   *   "NEW"; then set a flag to wipe the server and all other clients. On the
+   *   next sync, we'll replace their bookmarks with ours.
+   *
+   * - RESTORE_ON_STARTUP: Places is automatically restoring from a backup to
+   *   recover from a corrupt database. The sync ID, last sync time, and
+   *   tombstones don't exist, since we don't back them up; reset sync statuses
+   *   for the roots to "UNKNOWN"; but don't wipe the server. On the next sync,
+   *   we'll merge the restored bookmarks with the ones on the server.
+   *
+   * - SYNC: Either another client told us to erase our bookmarks
+   *   (`PlacesSyncUtils.bookmarks.wipe`), or the user disconnected Sync
+   *   (`PlacesSyncUtils.bookmarks.reset`). In both cases, drop the existing
+   *   sync ID, last sync time, and tombstones; reset sync statuses for
+   *   remaining items to "NEW"; and don't wipe the server.
+   *
+   * @param db
+   *        the Sqlite.sys.mjs connection handle.
+   * @param source
+   *        the change source constant.
+   */
+  async resetSyncMetadata(db, source) {
+    if (
+      ![
+        lazy.PlacesUtils.bookmarks.SOURCES.RESTORE,
+        lazy.PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+        lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+      ].includes(source)
+    ) {
+      return;
+    }
+
+    // Remove the sync ID and last sync time in all cases.
+    await lazy.PlacesUtils.metadata.deleteWithConnection(
+      db,
+      BookmarkSyncUtils.SYNC_ID_META_KEY,
+      BookmarkSyncUtils.LAST_SYNC_META_KEY
+    );
+
+    // If we're manually restoring from a backup, wipe the server and other
+    // clients, so that we replace their bookmarks with the restored tree. If
+    // we're automatically restoring to recover from a corrupt database, don't
+    // wipe; we want to merge the restored tree with the one on the server.
+    await lazy.PlacesUtils.metadata.setWithConnection(
+      db,
+      new Map([
+        [
+          BookmarkSyncUtils.WIPE_REMOTE_META_KEY,
+          source == lazy.PlacesUtils.bookmarks.SOURCES.RESTORE,
+        ],
+      ])
+    );
+
+    // Reset change counters and sync statuses for roots and remaining
+    // items, and drop tombstones.
+    let syncStatus =
+      source == lazy.PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP
+        ? lazy.PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN
+        : lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW;
+    await resetAllSyncStatuses(db, syncStatus);
+  },
+
+  /**
+   * Converts a Places GUID to a Sync record ID. Record IDs are identical to
+   * Places GUIDs for all items except roots.
+   */
+  guidToRecordId(guid) {
+    return lazy.ROOT_GUID_TO_RECORD_ID[guid] || guid;
+  },
+
+  /**
+   * Converts a Sync record ID to a Places GUID.
+   */
+  recordIdToGuid(recordId) {
+    return lazy.ROOT_RECORD_ID_TO_GUID[recordId] || recordId;
+  },
+
+  /**
+   * Fetches the record IDs for a folder's children, ordered by their position
+   * within the folder.
+   * Used only be tests - but that includes tps, so it lives here.
+   */
+  fetchChildRecordIds(parentRecordId) {
+    lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.recordId(parentRecordId);
+    let parentGuid = BookmarkSyncUtils.recordIdToGuid(parentRecordId);
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: fetchChildRecordIds",
+      async function (db) {
+        let childGuids = await fetchChildGuids(db, parentGuid);
+        return childGuids.map(guid => BookmarkSyncUtils.guidToRecordId(guid));
+      }
+    );
+  },
+
+  /**
+   * Migrates an array of `{ recordId, modified }` tuples from the old JSON-based
+   * tracker to the new sync change counter. `modified` is when the change was
+   * added to the old tracker, in milliseconds.
+   *
+   * Sync calls this method before the first bookmark sync after the Places
+   * schema migration.
+   */
+  migrateOldTrackerEntries(entries) {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: migrateOldTrackerEntries",
+      function (db) {
+        return db.executeTransaction(async function () {
+          // Mark all existing bookmarks as synced, and clear their change
+          // counters to avoid a full upload on the next sync. Note that
+          // this means we'll miss changes made between startup and the first
+          // post-migration sync, as well as changes made on a new release
+          // channel that weren't synced before the user downgraded. This is
+          // unfortunate, but no worse than the behavior of the old tracker.
+          //
+          // We also likely have bookmarks that don't exist on the server,
+          // because the old tracker missed them. We'll eventually fix the
+          // server once we decide on a repair strategy.
+          await db.executeCached(
+            `
+            WITH RECURSIVE
+            syncedItems(id) AS (
+              SELECT b.id FROM moz_bookmarks b
+              WHERE b.guid IN ('menu________', 'toolbar_____', 'unfiled_____',
+                               'mobile______')
+              UNION ALL
+              SELECT b.id FROM moz_bookmarks b
+              JOIN syncedItems s ON b.parent = s.id
+            )
+            UPDATE moz_bookmarks SET
+              syncStatus = :syncStatus,
+              syncChangeCounter = 0
+            WHERE id IN syncedItems`,
+            { syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL }
+          );
+
+          await db.executeCached(`DELETE FROM moz_bookmarks_deleted`);
+
+          await db.executeCached(`CREATE TEMP TABLE moz_bookmarks_tracked (
+            guid TEXT PRIMARY KEY,
+            time INTEGER
+          )`);
+
+          try {
+            for (let { recordId, modified } of entries) {
+              let guid = BookmarkSyncUtils.recordIdToGuid(recordId);
+              if (!lazy.PlacesUtils.isValidGuid(guid)) {
+                lazy.BookmarkSyncLog.warn(
+                  `migrateOldTrackerEntries: Ignoring ` +
+                    `change for invalid item ${guid}`
+                );
+                continue;
+              }
+              let time = lazy.PlacesUtils.toPRTime(
+                Number.isFinite(modified) ? modified : Date.now()
+              );
+              await db.executeCached(
+                `
+                INSERT OR IGNORE INTO moz_bookmarks_tracked (guid, time)
+                VALUES (:guid, :time)`,
+                { guid, time }
+              );
+            }
+
+            // Bump the change counter for existing tracked items.
+            await db.executeCached(`
+              INSERT OR REPLACE INTO moz_bookmarks (id, fk, type, parent,
+                                                    position, title,
+                                                    dateAdded, lastModified,
+                                                    guid, syncChangeCounter,
+                                                    syncStatus)
+              SELECT b.id, b.fk, b.type, b.parent, b.position, b.title,
+                     b.dateAdded, MAX(b.lastModified, t.time), b.guid,
+                     b.syncChangeCounter + 1, b.syncStatus
+              FROM moz_bookmarks b
+              JOIN moz_bookmarks_tracked t ON b.guid = t.guid`);
+
+            // Insert tombstones for nonexistent tracked items, using the most
+            // recent deletion date for more accurate reconciliation. We assume
+            // the tracked item belongs to a synced root.
+            await db.executeCached(`
+              INSERT OR REPLACE INTO moz_bookmarks_deleted (guid, dateRemoved)
+              SELECT t.guid, MAX(IFNULL((SELECT dateRemoved FROM moz_bookmarks_deleted
+                                         WHERE guid = t.guid), 0), t.time)
+              FROM moz_bookmarks_tracked t
+              LEFT JOIN moz_bookmarks b ON t.guid = b.guid
+              WHERE b.guid IS NULL`);
+          } finally {
+            await db.executeCached(`DROP TABLE moz_bookmarks_tracked`);
+          }
+        });
+      }
+    );
+  },
+
+  /**
+   * Reorders a folder's children, based on their order in the array of sync
+   * IDs.
+   *
+   * Sync uses this method to reorder all synced children after applying all
+   * incoming records.
+   *
+   * @return {Promise} resolved when reordering is complete.
+   * @rejects if an error happens while reordering.
+   * @throws if the arguments are invalid.
+   */
+  order(parentRecordId, childRecordIds) {
+    lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS.recordId(parentRecordId);
+    if (!childRecordIds.length) {
+      return undefined;
+    }
+    let parentGuid = BookmarkSyncUtils.recordIdToGuid(parentRecordId);
+    if (parentGuid == lazy.PlacesUtils.bookmarks.rootGuid) {
+      // Reordering roots doesn't make sense, but Sync will do this on the
+      // first sync.
+      return undefined;
+    }
+    let orderedChildrenGuids = childRecordIds.map(
+      BookmarkSyncUtils.recordIdToGuid
+    );
+    return lazy.PlacesUtils.bookmarks.reorder(
+      parentGuid,
+      orderedChildrenGuids,
+      {
+        source: SOURCE_SYNC,
+      }
+    );
+  },
+
+  /**
+   * Resolves to true if there are known sync changes.
+   */
+  havePendingChanges() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: havePendingChanges",
+      async function (db) {
+        let rows = await db.executeCached(`
+          WITH RECURSIVE
+          syncedItems(id, guid, syncChangeCounter) AS (
+            SELECT b.id, b.guid, b.syncChangeCounter
+             FROM moz_bookmarks b
+             WHERE b.guid IN ('menu________', 'toolbar_____', 'unfiled_____',
+                              'mobile______')
+            UNION ALL
+            SELECT b.id, b.guid, b.syncChangeCounter
+            FROM moz_bookmarks b
+            JOIN syncedItems s ON b.parent = s.id
+          ),
+          changedItems(guid) AS (
+            SELECT guid FROM syncedItems
+            WHERE syncChangeCounter >= 1
+            UNION ALL
+            SELECT guid FROM moz_bookmarks_deleted
+          )
+          SELECT EXISTS(SELECT guid FROM changedItems) AS haveChanges`);
+        return !!rows[0].getResultByName("haveChanges");
+      }
+    );
+  },
+
+  /**
+   * Returns a changeset containing local bookmark changes since the last sync.
+   *
+   * @return {Promise} resolved once all items have been fetched.
+   * @resolves to an object containing records for changed bookmarks, keyed by
+   *           the record ID.
+   * @see pullSyncChanges for the implementation, and markChangesAsSyncing for
+   *      an explanation of why we update the sync status.
+   */
+  pullChanges() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: pullChanges",
+      pullSyncChanges
+    );
+  },
+
+  /**
+   * Updates the sync status of all "NEW" bookmarks to "NORMAL", so that Sync
+   * can recover correctly after an interrupted sync.
+   *
+   * @param changeRecords
+   *        A changeset containing sync change records, as returned by
+   *        `pullChanges`.
+   * @return {Promise} resolved once all records have been updated.
+   */
+  markChangesAsSyncing(changeRecords) {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: markChangesAsSyncing",
+      db => markChangesAsSyncing(db, changeRecords)
+    );
+  },
+
+  /**
+   * Decrements the sync change counter, updates the sync status, and cleans up
+   * tombstones for successfully synced items. Sync calls this method at the
+   * end of each bookmark sync.
+   *
+   * @param changeRecords
+   *        A changeset containing sync change records, as returned by
+   *        `pullChanges`.
+   * @return {Promise} resolved once all records have been updated.
+   */
+  pushChanges(changeRecords) {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: pushChanges",
+      async function (db) {
+        let skippedCount = 0;
+        let weakCount = 0;
+        let updateParams = [];
+        let tombstoneGuidsToRemove = [];
+
+        for (let recordId in changeRecords) {
+          // Validate change records to catch coding errors.
+          let changeRecord = validateChangeRecord(
+            "BookmarkSyncUtils: pushChanges",
+            changeRecords[recordId],
+            {
+              tombstone: { required: true },
+              counter: { required: true },
+              synced: { required: true },
+            }
+          );
+
+          // Skip weakly uploaded records.
+          if (!changeRecord.counter) {
+            weakCount++;
+            continue;
+          }
+
+          // Sync sets the `synced` flag for reconciled or successfully
+          // uploaded items. If upload failed, ignore the change; we'll
+          // try again on the next sync.
+          if (!changeRecord.synced) {
+            skippedCount++;
+            continue;
+          }
+
+          let guid = BookmarkSyncUtils.recordIdToGuid(recordId);
+          if (changeRecord.tombstone) {
+            tombstoneGuidsToRemove.push(guid);
+          } else {
+            updateParams.push({
+              guid,
+              syncChangeDelta: changeRecord.counter,
+              syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+            });
+          }
+        }
+
+        // Reduce the change counter and update the sync status for
+        // reconciled and uploaded items. If the bookmark was updated
+        // during the sync, its change counter will still be > 0 for the
+        // next sync.
+        if (updateParams.length || tombstoneGuidsToRemove.length) {
+          await db.executeTransaction(async function () {
+            if (updateParams.length) {
+              await db.executeCached(
+                `
+                UPDATE moz_bookmarks
+                SET syncChangeCounter = MAX(syncChangeCounter - :syncChangeDelta, 0),
+                    syncStatus = :syncStatus
+                WHERE guid = :guid`,
+                updateParams
+              );
+              // and if there are *both* bookmarks and tombstones for these
+              // items, we nuke the tombstones.
+              // This should be unlikely, but bad if it happens.
+              let dupedGuids = updateParams.map(({ guid }) => guid);
+              await removeUndeletedTombstones(db, dupedGuids);
+            }
+            await removeTombstones(db, tombstoneGuidsToRemove);
+          });
+        }
+
+        lazy.BookmarkSyncLog.debug(`pushChanges: Processed change records`, {
+          weak: weakCount,
+          skipped: skippedCount,
+          updated: updateParams.length,
+        });
+      }
+    );
+  },
+
+  /**
+   * Removes items from the database. Sync buffers incoming tombstones, and
+   * calls this method to apply them at the end of each sync. Deletion
+   * happens in three steps:
+   *
+   *  1. Remove all non-folder items. Deleting a folder on a remote client
+   *     uploads tombstones for the folder and its children at the time of
+   *     deletion. This preserves any new children we've added locally since
+   *     the last sync.
+   *  2. Reparent remaining children to the tombstoned folder's parent. This
+   *     bumps the change counter for the children and their new parent.
+   *  3. Remove the tombstoned folder. Because we don't do this in a
+   *     transaction, the user might move new items into the folder before we
+   *     can remove it. In that case, we keep the folder and upload the new
+   *     subtree to the server.
+   *
+   * See the comment above `BookmarksStore::deletePending` for the details on
+   * why delete works the way it does.
+   */
+  remove(recordIds) {
+    if (!recordIds.length) {
+      return null;
+    }
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: remove",
+      async function (db) {
+        let folderGuids = [];
+        for (let recordId of recordIds) {
+          if (recordId in lazy.ROOT_RECORD_ID_TO_GUID) {
+            lazy.BookmarkSyncLog.warn(
+              `remove: Refusing to remove root ${recordId}`
+            );
+            continue;
+          }
+          let guid = BookmarkSyncUtils.recordIdToGuid(recordId);
+          let bookmarkItem = await lazy.PlacesUtils.bookmarks.fetch(guid);
+          if (!bookmarkItem) {
+            lazy.BookmarkSyncLog.trace(`remove: Item ${guid} already removed`);
+            continue;
+          }
+          let kind = await getKindForItem(db, bookmarkItem);
+          if (kind == BookmarkSyncUtils.KINDS.FOLDER) {
+            folderGuids.push(bookmarkItem.guid);
+            continue;
+          }
+          let wasRemoved = await deleteSyncedAtom(bookmarkItem);
+          if (wasRemoved) {
+            lazy.BookmarkSyncLog.trace(
+              `remove: Removed item ${guid} with kind ${kind}`
+            );
+          }
+        }
+
+        for (let guid of folderGuids) {
+          let bookmarkItem = await lazy.PlacesUtils.bookmarks.fetch(guid);
+          if (!bookmarkItem) {
+            lazy.BookmarkSyncLog.trace(
+              `remove: Folder ${guid} already removed`
+            );
+            continue;
+          }
+          let wasRemoved = await deleteSyncedFolder(db, bookmarkItem);
+          if (wasRemoved) {
+            lazy.BookmarkSyncLog.trace(
+              `remove: Removed folder ${bookmarkItem.guid}`
+            );
+          }
+        }
+
+        // TODO (Bug 1313890): Refactor the bookmarks engine to pull change records
+        // before uploading, instead of returning records to merge into the engine's
+        // initial changeset.
+        return pullSyncChanges(db);
+      }
+    );
+  },
+
+  /**
+   * Removes all bookmarks and tombstones from the database. Sync calls this
+   * method when it receives a command from a remote client to wipe all stored
+   * data.
+   *
+   * @return {Promise} resolved once all items have been removed.
+   */
+  wipe() {
+    return lazy.PlacesUtils.bookmarks.eraseEverything({
+      source: SOURCE_SYNC,
+    });
+  },
+
+  /**
+   * Marks all bookmarks as "NEW" and removes all tombstones. Unlike `wipe`,
+   * this keeps all existing bookmarks, and only clears their sync change
+   * tracking info.
+   *
+   * @return {Promise} resolved once all items have been updated.
+   */
+  reset() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: reset",
+      function (db) {
+        return db.executeTransaction(async function () {
+          await BookmarkSyncUtils.resetSyncMetadata(db, SOURCE_SYNC);
+        });
+      }
+    );
+  },
+
+  /**
+   * Fetches a Sync bookmark object for an item in the tree.
+   *
+   * Should only be used by SYNC TESTS.
+   * We should remove this in bug XXXXXX, updating the tests to use
+   * PlacesUtils.bookmarks.fetch.
+   *
+   * The object contains
+   * the following properties, depending on the item's kind:
+   *
+   *  - kind (all): A string representing the item's kind.
+   *  - recordId (all): The item's record ID.
+   *  - parentRecordId (all): The record ID of the item's parent.
+   *  - parentTitle (all): The title of the item's parent, used for de-duping.
+   *    Omitted for the Places root and parents with empty titles.
+   *  - dateAdded (all): Timestamp in milliseconds, when the bookmark was added
+   *    or created on a remote device if known.
+   *  - title ("bookmark", "folder", "query"): The item's title.
+   *    Omitted if empty.
+   *  - url ("bookmark", "query"): The item's URL.
+   *  - tags ("bookmark", "query"): An array containing the item's tags.
+   *  - keyword ("bookmark"): The bookmark's keyword, if one exists.
+   *  - childRecordIds ("folder"): An array containing the record IDs of the item's
+   *    children, used to determine child order.
+   *  - folder ("query"): The tag folder name, if this is a tag query.
+   *  - index ("separator"): The separator's position within its parent.
+   */
+  async fetch(recordId) {
+    let guid = BookmarkSyncUtils.recordIdToGuid(recordId);
+    let bookmarkItem = await lazy.PlacesUtils.bookmarks.fetch(guid);
+    if (!bookmarkItem) {
+      return null;
+    }
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkSyncUtils: fetch",
+      async function (db) {
+        // Convert the Places bookmark object to a Sync bookmark and add
+        // kind-specific properties. Titles are required for bookmarks,
+        // and folders; optional for queries, and omitted for separators.
+        let kind = await getKindForItem(db, bookmarkItem);
+        let item;
+        switch (kind) {
+          case BookmarkSyncUtils.KINDS.BOOKMARK:
+            item = await fetchBookmarkItem(db, bookmarkItem);
+            break;
+
+          case BookmarkSyncUtils.KINDS.QUERY:
+            item = await fetchQueryItem(db, bookmarkItem);
+            break;
+
+          case BookmarkSyncUtils.KINDS.FOLDER:
+            item = await fetchFolderItem(db, bookmarkItem);
+            break;
+
+          case BookmarkSyncUtils.KINDS.SEPARATOR:
+            item = await placesBookmarkToSyncBookmark(db, bookmarkItem);
+            item.index = bookmarkItem.index;
+            break;
+
+          default:
+            throw new Error(`Unknown bookmark kind: ${kind}`);
+        }
+
+        // Sync uses the parent title for de-duping. All Sync bookmark objects
+        // except the Places root should have this property.
+        if (bookmarkItem.parentGuid) {
+          let parent = await lazy.PlacesUtils.bookmarks.fetch(
+            bookmarkItem.parentGuid
+          );
+          item.parentTitle = parent.title || "";
+        }
+
+        return item;
+      }
+    );
+  },
+
+  /**
+   * Returns the sync change counter increment for a change source constant.
+   */
+  determineSyncChangeDelta(source) {
+    // Don't bump the change counter when applying changes made by Sync, to
+    // avoid sync loops.
+    return source == lazy.PlacesUtils.bookmarks.SOURCES.SYNC ? 0 : 1;
+  },
+
+  /**
+   * Returns the sync status for a new item inserted by a change source.
+   */
+  determineInitialSyncStatus(source) {
+    if (source == lazy.PlacesUtils.bookmarks.SOURCES.SYNC) {
+      // Incoming bookmarks are "NORMAL", since they already exist on the server.
+      return lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL;
+    }
+    if (source == lazy.PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP) {
+      // If the user restores from a backup, or Places automatically recovers
+      // from a corrupt database, all prior sync tracking is lost. Setting the
+      // status to "UNKNOWN" allows Sync to reconcile restored bookmarks with
+      // those on the server.
+      return lazy.PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN;
+    }
+    // For all other sources, mark items as "NEW". We'll update their statuses
+    // to "NORMAL" after the first sync.
+    return lazy.PlacesUtils.bookmarks.SYNC_STATUS.NEW;
+  },
+
+  /**
+   * An internal helper that bumps the change counter for all bookmarks with
+   * a given URL. This is used to update bookmarks when adding or changing a
+   * tag or keyword entry.
+   *
+   * @param db
+   *        the Sqlite.sys.mjs connection handle.
+   * @param url
+   *        the bookmark URL object.
+   * @param syncChangeDelta
+   *        the sync change counter increment.
+   * @return {Promise} resolved when the counters have been updated.
+   */
+  addSyncChangesForBookmarksWithURL(db, url, syncChangeDelta) {
+    if (!url || !syncChangeDelta) {
+      return Promise.resolve();
+    }
+    return db.executeCached(
+      `
+      UPDATE moz_bookmarks
+        SET syncChangeCounter = syncChangeCounter + :syncChangeDelta
+      WHERE type = :type AND
+            fk = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND
+                  url = :url)`,
+      {
+        syncChangeDelta,
+        type: lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: url.href,
+      }
+    );
+  },
+
+  /**
+   * Returns `0` if no sensible timestamp could be found.
+   * Otherwise, returns the earliest sensible timestamp between `existingMillis`
+   * and `serverMillis`.
+   */
+  ratchetTimestampBackwards(
+    existingMillis,
+    serverMillis,
+    lowerBound = BookmarkSyncUtils.EARLIEST_BOOKMARK_TIMESTAMP
+  ) {
+    const possible = [+existingMillis, +serverMillis].filter(
+      n => !isNaN(n) && n > lowerBound
+    );
+    if (!possible.length) {
+      return 0;
+    }
+    return Math.min(...possible);
+  },
+
+  /**
+   * Rebuilds the left pane query for the mobile root under "All Bookmarks" if
+   * necessary. Sync calls this method at the end of each bookmark sync. This
+   * code should eventually move to `PlacesUIUtils#maybeRebuildLeftPane`; see
+   * bug 647605.
+   *
+   * - If there are no mobile bookmarks, the query will not be created, or
+   *   will be removed if it already exists.
+   * - If there are mobile bookmarks, the query will be created if it doesn't
+   *   exist, or will be updated with the correct title and URL otherwise.
+   */
+  async ensureMobileQuery() {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+
+    let mobileChildGuids = await fetchChildGuids(
+      db,
+      lazy.PlacesUtils.bookmarks.mobileGuid
+    );
+    let hasMobileBookmarks = !!mobileChildGuids.length;
+
+    Services.prefs.setBoolPref(MOBILE_BOOKMARKS_PREF, hasMobileBookmarks);
+  },
+}));
+
+PlacesSyncUtils.test = {};
+PlacesSyncUtils.test.bookmarks = Object.freeze({
+  /**
+   * Inserts a synced bookmark into the tree. Only SYNC TESTS should call this
+   * method; other callers should use `PlacesUtils.bookmarks.insert`.
+   *
+   * It is in this file rather than a test-only file because it makes use of
+   * other internal functions here, so moving is not trivial - see bug 1662602.
+   *
+   * The following properties are supported:
+   *  - kind: Required.
+   *  - guid: Required.
+   *  - parentGuid: Required.
+   *  - url: Required for bookmarks.
+   *  - tags: An optional array of tag strings.
+   *  - keyword: An optional keyword string.
+   *
+   * Sync doesn't set the index, since it appends and reorders children
+   * after applying all incoming items.
+   *
+   * @param info
+   *        object representing a synced bookmark.
+   *
+   * @return {Promise} resolved when the creation is complete.
+   * @resolves to an object representing the created bookmark.
+   * @rejects if it's not possible to create the requested bookmark.
+   * @throws if the arguments are invalid.
+   */
+  insert(info) {
+    let insertInfo = validateNewBookmark("BookmarkTestUtils: insert", info);
+
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "BookmarkTestUtils: insert",
+      async db => {
+        // If we're inserting a tag query, make sure the tag exists and fix the
+        // folder ID to refer to the local tag folder.
+        insertInfo = await updateTagQueryFolder(db, insertInfo);
+
+        let bookmarkInfo = syncBookmarkToPlacesBookmark(insertInfo);
+        let bookmarkItem = await lazy.PlacesUtils.bookmarks.insert(
+          bookmarkInfo
+        );
+        let newItem = await insertBookmarkMetadata(
+          db,
+          bookmarkItem,
+          insertInfo
+        );
+
+        return newItem;
+      }
+    );
+  },
+});
+
+ChromeUtils.defineLazyGetter(lazy, "HistorySyncLog", () => {
+  return lazy.Log.repository.getLogger("Sync.Engine.History.HistorySyncUtils");
+});
+
+ChromeUtils.defineLazyGetter(lazy, "BookmarkSyncLog", () => {
+  // Use a sub-log of the bookmarks engine, so setting the level for that
+  // engine also adjust the level of this log.
+  return lazy.Log.repository.getLogger(
+    "Sync.Engine.Bookmarks.BookmarkSyncUtils"
+  );
+});
+
+function validateSyncBookmarkObject(name, input, behavior) {
+  return lazy.PlacesUtils.validateItemProperties(
+    name,
+    lazy.PlacesUtils.SYNC_BOOKMARK_VALIDATORS,
+    input,
+    behavior
+  );
+}
+
+// Validates a sync change record as returned by `pullChanges` and passed to
+// `pushChanges`.
+function validateChangeRecord(name, changeRecord, behavior) {
+  return lazy.PlacesUtils.validateItemProperties(
+    name,
+    lazy.PlacesUtils.SYNC_CHANGE_RECORD_VALIDATORS,
+    changeRecord,
+    behavior
+  );
+}
+
+// Similar to the private `fetchBookmarksByParent` implementation in
+// `Bookmarks.jsm`.
+var fetchChildGuids = async function (db, parentGuid) {
+  let rows = await db.executeCached(
+    `
+    SELECT guid
+    FROM moz_bookmarks
+    WHERE parent = (
+      SELECT id FROM moz_bookmarks WHERE guid = :parentGuid
+    )
+    ORDER BY position`,
+    { parentGuid }
+  );
+  return rows.map(row => row.getResultByName("guid"));
+};
+
+// Legacy tag queries may use a `place:` URL that refers to the tag folder ID.
+// When we apply a synced tag query from a remote client, we need to update the
+// URL to point to the local tag.
+function updateTagQueryFolder(db, info) {
+  if (
+    info.kind != BookmarkSyncUtils.KINDS.QUERY ||
+    !info.folder ||
+    !info.url ||
+    info.url.protocol != "place:"
+  ) {
+    return info;
+  }
+
+  let params = new URLSearchParams(info.url.pathname);
+  let type = +params.get("type");
+  if (type != Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAG_CONTENTS) {
+    return info;
+  }
+
+  lazy.BookmarkSyncLog.debug(
+    `updateTagQueryFolder: Tag query folder: ${info.folder}`
+  );
+
+  // Rewrite the query to directly reference the tag.
+  params.delete("queryType");
+  params.delete("type");
+  params.delete("folder");
+  params.set("tag", info.folder);
+  info.url = new URL(info.url.protocol + params);
+  return info;
+}
+
+// Keywords are a 1 to 1 mapping between strings and pairs of (URL, postData).
+// (the postData is not synced, so we ignore it). Sync associates keywords with
+// bookmarks, which is not really accurate. -- We might already have a keyword
+// with that name, or we might already have another bookmark with that URL with
+// a different keyword, etc.
+//
+// If we don't handle those cases by removing the conflicting keywords first,
+// the insertion  will fail, and the keywords will either be wrong, or missing.
+// This function handles those cases.
+function removeConflictingKeywords(bookmarkURL, newKeyword) {
+  return lazy.PlacesUtils.withConnectionWrapper(
+    "BookmarkSyncUtils: removeConflictingKeywords",
+    async function (db) {
+      let entryForURL = await lazy.PlacesUtils.keywords.fetch({
+        url: bookmarkURL.href,
+      });
+      if (entryForURL && entryForURL.keyword !== newKeyword) {
+        await lazy.PlacesUtils.keywords.remove({
+          keyword: entryForURL.keyword,
+          source: SOURCE_SYNC,
+        });
+        // This will cause us to reupload this record for this sync, but
+        // without it, we will risk data corruption.
+        await BookmarkSyncUtils.addSyncChangesForBookmarksWithURL(
+          db,
+          entryForURL.url,
+          1
+        );
+      }
+      if (!newKeyword) {
+        return;
+      }
+      let entryForNewKeyword = await lazy.PlacesUtils.keywords.fetch({
+        keyword: newKeyword,
+      });
+      if (entryForNewKeyword) {
+        await lazy.PlacesUtils.keywords.remove({
+          keyword: entryForNewKeyword.keyword,
+          source: SOURCE_SYNC,
+        });
+        await BookmarkSyncUtils.addSyncChangesForBookmarksWithURL(
+          db,
+          entryForNewKeyword.url,
+          1
+        );
+      }
+    }
+  );
+}
+
+// Sets annotations, keywords, and tags on a new bookmark. Returns a Sync
+// bookmark object.
+async function insertBookmarkMetadata(db, bookmarkItem, insertInfo) {
+  let newItem = await placesBookmarkToSyncBookmark(db, bookmarkItem);
+
+  try {
+    newItem.tags = tagItem(bookmarkItem, insertInfo.tags);
+  } catch (ex) {
+    lazy.BookmarkSyncLog.warn(
+      `insertBookmarkMetadata: Error tagging item ${insertInfo.recordId}`,
+      ex
+    );
+  }
+
+  if (insertInfo.keyword) {
+    await removeConflictingKeywords(bookmarkItem.url, insertInfo.keyword);
+    await lazy.PlacesUtils.keywords.insert({
+      keyword: insertInfo.keyword,
+      url: bookmarkItem.url.href,
+      source: SOURCE_SYNC,
+    });
+    newItem.keyword = insertInfo.keyword;
+  }
+
+  return newItem;
+}
+
+// Determines the Sync record kind for an existing bookmark.
+async function getKindForItem(db, item) {
+  switch (item.type) {
+    case lazy.PlacesUtils.bookmarks.TYPE_FOLDER: {
+      return BookmarkSyncUtils.KINDS.FOLDER;
+    }
+    case lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK:
+      return item.url.protocol == "place:"
+        ? BookmarkSyncUtils.KINDS.QUERY
+        : BookmarkSyncUtils.KINDS.BOOKMARK;
+
+    case lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR:
+      return BookmarkSyncUtils.KINDS.SEPARATOR;
+  }
+  return null;
+}
+
+// Returns the `nsINavBookmarksService` bookmark type constant for a Sync
+// record kind.
+function getTypeForKind(kind) {
+  switch (kind) {
+    case BookmarkSyncUtils.KINDS.BOOKMARK:
+    case BookmarkSyncUtils.KINDS.QUERY:
+      return lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK;
+
+    case BookmarkSyncUtils.KINDS.FOLDER:
+      return lazy.PlacesUtils.bookmarks.TYPE_FOLDER;
+
+    case BookmarkSyncUtils.KINDS.SEPARATOR:
+      return lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR;
+  }
+  throw new Error(`Unknown bookmark kind: ${kind}`);
+}
+
+function validateNewBookmark(name, info) {
+  let insertInfo = validateSyncBookmarkObject(name, info, {
+    kind: { required: true },
+    recordId: { required: true },
+    url: {
+      requiredIf: b =>
+        [
+          BookmarkSyncUtils.KINDS.BOOKMARK,
+          BookmarkSyncUtils.KINDS.QUERY,
+        ].includes(b.kind),
+      validIf: b =>
+        [
+          BookmarkSyncUtils.KINDS.BOOKMARK,
+          BookmarkSyncUtils.KINDS.QUERY,
+        ].includes(b.kind),
+    },
+    parentRecordId: { required: true },
+    title: {
+      validIf: b =>
+        [
+          BookmarkSyncUtils.KINDS.BOOKMARK,
+          BookmarkSyncUtils.KINDS.QUERY,
+          BookmarkSyncUtils.KINDS.FOLDER,
+        ].includes(b.kind) || b.title === "",
+    },
+    query: { validIf: b => b.kind == BookmarkSyncUtils.KINDS.QUERY },
+    folder: { validIf: b => b.kind == BookmarkSyncUtils.KINDS.QUERY },
+    tags: {
+      validIf: b =>
+        [
+          BookmarkSyncUtils.KINDS.BOOKMARK,
+          BookmarkSyncUtils.KINDS.QUERY,
+        ].includes(b.kind),
+    },
+    keyword: {
+      validIf: b =>
+        [
+          BookmarkSyncUtils.KINDS.BOOKMARK,
+          BookmarkSyncUtils.KINDS.QUERY,
+        ].includes(b.kind),
+    },
+    dateAdded: { required: false },
+  });
+
+  return insertInfo;
+}
+
+function tagItem(item, tags) {
+  if (!item.url) {
+    return [];
+  }
+
+  // Remove leading and trailing whitespace, then filter out empty tags.
+  let newTags = tags ? tags.map(tag => tag.trim()).filter(Boolean) : [];
+
+  // Removing the last tagged item will also remove the tag. To preserve
+  // tag IDs, we temporarily tag a dummy URI, ensuring the tags exist.
+  let dummyURI = lazy.PlacesUtils.toURI("about:weave#BStore_tagURI");
+  let bookmarkURI = lazy.PlacesUtils.toURI(item.url);
+  if (newTags && newTags.length) {
+    lazy.PlacesUtils.tagging.tagURI(dummyURI, newTags, SOURCE_SYNC);
+  }
+  lazy.PlacesUtils.tagging.untagURI(bookmarkURI, null, SOURCE_SYNC);
+  if (newTags && newTags.length) {
+    lazy.PlacesUtils.tagging.tagURI(bookmarkURI, newTags, SOURCE_SYNC);
+  }
+  lazy.PlacesUtils.tagging.untagURI(dummyURI, null, SOURCE_SYNC);
+
+  return newTags;
+}
+
+// Converts a Places bookmark to a Sync bookmark. This function maps Places
+// GUIDs to record IDs and filters out extra Places properties like date added,
+// last modified, and index.
+async function placesBookmarkToSyncBookmark(db, bookmarkItem) {
+  let item = {};
+
+  for (let prop in bookmarkItem) {
+    switch (prop) {
+      // Record IDs are identical to Places GUIDs for all items except roots.
+      case "guid":
+        item.recordId = BookmarkSyncUtils.guidToRecordId(bookmarkItem.guid);
+        break;
+
+      case "parentGuid":
+        item.parentRecordId = BookmarkSyncUtils.guidToRecordId(
+          bookmarkItem.parentGuid
+        );
+        break;
+
+      // Sync uses kinds instead of types, which distinguish between folders,
+      // livemarks, bookmarks, and queries.
+      case "type":
+        item.kind = await getKindForItem(db, bookmarkItem);
+        break;
+
+      case "title":
+      case "url":
+        item[prop] = bookmarkItem[prop];
+        break;
+
+      case "dateAdded":
+        item[prop] = new Date(bookmarkItem[prop]).getTime();
+        break;
+    }
+  }
+
+  return item;
+}
+
+// Converts a Sync bookmark object to a Places bookmark or livemark object.
+// This function maps record IDs to Places GUIDs, and filters out extra Sync
+// properties like keywords, tags. Returns an object that can be passed to
+// `PlacesUtils.bookmarks.{insert, update}`.
+function syncBookmarkToPlacesBookmark(info) {
+  let bookmarkInfo = {
+    source: SOURCE_SYNC,
+  };
+
+  for (let prop in info) {
+    switch (prop) {
+      case "kind":
+        bookmarkInfo.type = getTypeForKind(info.kind);
+        break;
+
+      // Convert record IDs to Places GUIDs for roots.
+      case "recordId":
+        bookmarkInfo.guid = BookmarkSyncUtils.recordIdToGuid(info.recordId);
+        break;
+
+      case "dateAdded":
+        bookmarkInfo.dateAdded = new Date(info.dateAdded);
+        break;
+
+      case "parentRecordId":
+        bookmarkInfo.parentGuid = BookmarkSyncUtils.recordIdToGuid(
+          info.parentRecordId
+        );
+        // Instead of providing an index, Sync reorders children at the end of
+        // the sync using `BookmarkSyncUtils.order`. We explicitly specify the
+        // default index here to prevent `PlacesUtils.bookmarks.update` from
+        // throwing.
+        bookmarkInfo.index = lazy.PlacesUtils.bookmarks.DEFAULT_INDEX;
+        break;
+
+      case "title":
+      case "url":
+        bookmarkInfo[prop] = info[prop];
+        break;
+    }
+  }
+
+  return bookmarkInfo;
+}
+
+// Creates and returns a Sync bookmark object containing the bookmark's
+// tags, keyword.
+var fetchBookmarkItem = async function (db, bookmarkItem) {
+  let item = await placesBookmarkToSyncBookmark(db, bookmarkItem);
+
+  if (!item.title) {
+    item.title = "";
+  }
+
+  item.tags = lazy.PlacesUtils.tagging.getTagsForURI(
+    lazy.PlacesUtils.toURI(bookmarkItem.url)
+  );
+
+  let keywordEntry = await lazy.PlacesUtils.keywords.fetch({
+    url: bookmarkItem.url,
+  });
+  if (keywordEntry) {
+    item.keyword = keywordEntry.keyword;
+  }
+
+  return item;
+};
+
+// Creates and returns a Sync bookmark object containing the folder's children.
+async function fetchFolderItem(db, bookmarkItem) {
+  let item = await placesBookmarkToSyncBookmark(db, bookmarkItem);
+
+  if (!item.title) {
+    item.title = "";
+  }
+
+  let childGuids = await fetchChildGuids(db, bookmarkItem.guid);
+  item.childRecordIds = childGuids.map(guid =>
+    BookmarkSyncUtils.guidToRecordId(guid)
+  );
+
+  return item;
+}
+
+// Creates and returns a Sync bookmark object containing the query's tag
+// folder name.
+async function fetchQueryItem(db, bookmarkItem) {
+  let item = await placesBookmarkToSyncBookmark(db, bookmarkItem);
+
+  let params = new URLSearchParams(bookmarkItem.url.pathname);
+  let tags = params.getAll("tag");
+  if (tags.length == 1) {
+    item.folder = tags[0];
+  }
+
+  return item;
+}
+
+function addRowToChangeRecords(row, changeRecords) {
+  let guid = row.getResultByName("guid");
+  if (!guid) {
+    throw new Error(`Changed item missing GUID`);
+  }
+  let isTombstone = !!row.getResultByName("tombstone");
+  let recordId = BookmarkSyncUtils.guidToRecordId(guid);
+  if (recordId in changeRecords) {
+    let existingRecord = changeRecords[recordId];
+    if (existingRecord.tombstone == isTombstone) {
+      // Should never happen: `moz_bookmarks.guid` has a unique index, and
+      // `moz_bookmarks_deleted.guid` is the primary key.
+      throw new Error(`Duplicate item or tombstone ${recordId} in changeset`);
+    }
+    if (!existingRecord.tombstone && isTombstone) {
+      // Don't replace undeleted items with tombstones...
+      lazy.BookmarkSyncLog.warn(
+        "addRowToChangeRecords: Ignoring tombstone for undeleted item",
+        recordId
+      );
+      return;
+    }
+    // ...But replace undeleted tombstones with items.
+    lazy.BookmarkSyncLog.warn(
+      "addRowToChangeRecords: Replacing tombstone for undeleted item",
+      recordId
+    );
+  }
+  let modifiedAsPRTime = row.getResultByName("modified");
+  let modified = modifiedAsPRTime / MICROSECONDS_PER_SECOND;
+  if (Number.isNaN(modified) || modified <= 0) {
+    lazy.BookmarkSyncLog.error(
+      "addRowToChangeRecords: Invalid modified date for " + recordId,
+      modifiedAsPRTime
+    );
+    modified = 0;
+  }
+  changeRecords[recordId] = {
+    modified,
+    counter: row.getResultByName("syncChangeCounter"),
+    status: row.getResultByName("syncStatus"),
+    tombstone: isTombstone,
+    synced: false,
+  };
+}
+
+/**
+ * Queries the database for synced bookmarks and tombstones, and returns a
+ * changeset for the Sync bookmarks engine.
+ *
+ * @param db
+ *        The Sqlite.sys.mjs connection handle.
+ * @param forGuids
+ *        Fetch Sync tracking information for only the requested GUIDs.
+ * @return {Promise} resolved once all items have been fetched.
+ * @resolves to an object containing records for changed bookmarks, keyed by
+ *           the record ID.
+ */
+var pullSyncChanges = async function (db, forGuids = []) {
+  let changeRecords = {};
+
+  let itemConditions = ["syncChangeCounter >= 1"];
+  let tombstoneConditions = ["1 = 1"];
+  if (forGuids.length) {
+    let restrictToGuids = `guid IN (${forGuids
+      .map(guid => JSON.stringify(guid))
+      .join(",")})`;
+    itemConditions.push(restrictToGuids);
+    tombstoneConditions.push(restrictToGuids);
+  }
+
+  let rows = await db.executeCached(
+    `
+    WITH RECURSIVE
+    syncedItems(id, guid, modified, syncChangeCounter, syncStatus) AS (
+      SELECT b.id, b.guid, b.lastModified, b.syncChangeCounter, b.syncStatus
+       FROM moz_bookmarks b
+       WHERE b.guid IN ('menu________', 'toolbar_____', 'unfiled_____',
+                        'mobile______')
+      UNION ALL
+      SELECT b.id, b.guid, b.lastModified, b.syncChangeCounter, b.syncStatus
+      FROM moz_bookmarks b
+      JOIN syncedItems s ON b.parent = s.id
+    )
+    SELECT guid, modified, syncChangeCounter, syncStatus, 0 AS tombstone
+    FROM syncedItems
+    WHERE ${itemConditions.join(" AND ")}
+    UNION ALL
+    SELECT guid, dateRemoved AS modified, 1 AS syncChangeCounter,
+           :deletedSyncStatus, 1 AS tombstone
+    FROM moz_bookmarks_deleted
+    WHERE ${tombstoneConditions.join(" AND ")}`,
+    { deletedSyncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL }
+  );
+  for (let row of rows) {
+    addRowToChangeRecords(row, changeRecords);
+  }
+
+  return changeRecords;
+};
+
+// Moves a synced folder's remaining children to its parent, and deletes the
+// folder if it's empty.
+async function deleteSyncedFolder(db, bookmarkItem) {
+  // At this point, any member in the folder that remains is either a folder
+  // pending deletion (which we'll get to in this function), or an item that
+  // should not be deleted. To avoid deleting these items, we first move them
+  // to the parent of the folder we're about to delete.
+  let childGuids = await fetchChildGuids(db, bookmarkItem.guid);
+  if (!childGuids.length) {
+    // No children -- just delete the folder.
+    return deleteSyncedAtom(bookmarkItem);
+  }
+
+  if (lazy.BookmarkSyncLog.level <= lazy.Log.Level.Trace) {
+    lazy.BookmarkSyncLog.trace(
+      `deleteSyncedFolder: Moving ${JSON.stringify(childGuids)} children of ` +
+        `"${bookmarkItem.guid}" to grandparent
+      "${BookmarkSyncUtils.guidToRecordId(bookmarkItem.parentGuid)}" before ` +
+        `deletion`
+    );
+  }
+
+  // Move children out of the parent and into the grandparent
+  for (let guid of childGuids) {
+    await lazy.PlacesUtils.bookmarks.update({
+      guid,
+      parentGuid: bookmarkItem.parentGuid,
+      index: lazy.PlacesUtils.bookmarks.DEFAULT_INDEX,
+      // `SYNC_REPARENT_REMOVED_FOLDER_CHILDREN` bumps the change counter for
+      // the child and its new parent, without incrementing the bookmark
+      // tracker's score.
+      //
+      // We intentionally don't check if the child is one we'll remove later,
+      // so it's possible we'll bump the change counter of the closest living
+      // ancestor when it's not needed. This avoids inconsistency if removal
+      // is interrupted, since we don't run this operation in a transaction.
+      source:
+        lazy.PlacesUtils.bookmarks.SOURCES
+          .SYNC_REPARENT_REMOVED_FOLDER_CHILDREN,
+    });
+  }
+
+  // Delete the (now empty) parent
+  try {
+    await lazy.PlacesUtils.bookmarks.remove(bookmarkItem.guid, {
+      preventRemovalOfNonEmptyFolders: true,
+      // We don't want to bump the change counter for this deletion, because
+      // a tombstone for the folder is already on the server.
+      source: SOURCE_SYNC,
+    });
+  } catch (e) {
+    // We failed, probably because someone added something to this folder
+    // between when we got the children and now (or the database is corrupt,
+    // or something else happened...) This is unlikely, but possible. To
+    // avoid corruption in this case, we need to reupload the record to the
+    // server.
+    //
+    // (Ideally this whole operation would be done in a transaction, and this
+    // wouldn't be possible).
+    lazy.BookmarkSyncLog.trace(
+      `deleteSyncedFolder: Error removing parent ` +
+        `${bookmarkItem.guid} after reparenting children`,
+      e
+    );
+    return false;
+  }
+
+  return true;
+}
+
+// Removes a synced bookmark or empty folder from the database.
+var deleteSyncedAtom = async function (bookmarkItem) {
+  try {
+    await lazy.PlacesUtils.bookmarks.remove(bookmarkItem.guid, {
+      preventRemovalOfNonEmptyFolders: true,
+      source: SOURCE_SYNC,
+    });
+  } catch (ex) {
+    // Likely already removed.
+    lazy.BookmarkSyncLog.trace(
+      `deleteSyncedAtom: Error removing ` + bookmarkItem.guid,
+      ex
+    );
+    return false;
+  }
+
+  return true;
+};
+
+/**
+ * Updates the sync status on all "NEW" and "UNKNOWN" bookmarks to "NORMAL".
+ *
+ * We do this when pulling changes instead of in `pushChanges` to make sure
+ * we write tombstones if a new item is deleted after an interrupted sync. (For
+ * example, if a "NEW" record is uploaded or reconciled, then the app is closed
+ * before Sync calls `pushChanges`).
+ */
+function markChangesAsSyncing(db, changeRecords) {
+  let unsyncedGuids = [];
+  for (let recordId in changeRecords) {
+    if (changeRecords[recordId].tombstone) {
+      continue;
+    }
+    if (
+      changeRecords[recordId].status ==
+      lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    ) {
+      continue;
+    }
+    let guid = BookmarkSyncUtils.recordIdToGuid(recordId);
+    unsyncedGuids.push(JSON.stringify(guid));
+  }
+  if (!unsyncedGuids.length) {
+    return Promise.resolve();
+  }
+  return db.execute(
+    `
+    UPDATE moz_bookmarks
+    SET syncStatus = :syncStatus
+    WHERE guid IN (${unsyncedGuids.join(",")})`,
+    { syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL }
+  );
+}
+
+/**
+ * Removes tombstones for successfully synced items.
+ *
+ * @return {Promise}
+ */
+var removeTombstones = function (db, guids) {
+  if (!guids.length) {
+    return Promise.resolve();
+  }
+  return db.execute(`
+    DELETE FROM moz_bookmarks_deleted
+    WHERE guid IN (${guids.map(guid => JSON.stringify(guid)).join(",")})`);
+};
+
+/**
+ * Removes tombstones for successfully synced items where the specified GUID
+ * exists in *both* the bookmarks and tombstones tables.
+ *
+ * @return {Promise}
+ */
+var removeUndeletedTombstones = function (db, guids) {
+  if (!guids.length) {
+    return Promise.resolve();
+  }
+  // sqlite can't join in a DELETE, so we use a subquery.
+  return db.execute(`
+    DELETE FROM moz_bookmarks_deleted
+    WHERE guid IN (${guids.map(guid => JSON.stringify(guid)).join(",")})
+    AND guid IN (SELECT guid from moz_bookmarks)`);
+};
+
+// Sets the history sync ID and clears the last sync time.
+async function setHistorySyncId(db, newSyncId) {
+  await lazy.PlacesUtils.metadata.setWithConnection(
+    db,
+    new Map([[HistorySyncUtils.SYNC_ID_META_KEY, newSyncId]])
+  );
+
+  await lazy.PlacesUtils.metadata.deleteWithConnection(
+    db,
+    HistorySyncUtils.LAST_SYNC_META_KEY
+  );
+}
+
+// Sets the bookmarks sync ID and clears the last sync time.
+async function setBookmarksSyncId(db, newSyncId) {
+  await lazy.PlacesUtils.metadata.setWithConnection(
+    db,
+    new Map([[BookmarkSyncUtils.SYNC_ID_META_KEY, newSyncId]])
+  );
+
+  await lazy.PlacesUtils.metadata.deleteWithConnection(
+    db,
+    BookmarkSyncUtils.LAST_SYNC_META_KEY,
+    BookmarkSyncUtils.WIPE_REMOTE_META_KEY
+  );
+}
+
+// Bumps the change counter and sets the given sync status for all bookmarks,
+// and drops stale tombstones.
+async function resetAllSyncStatuses(db, syncStatus) {
+  await db.execute(
+    `
+    UPDATE moz_bookmarks
+    SET syncChangeCounter = 1,
+        syncStatus = :syncStatus`,
+    { syncStatus }
+  );
+
+  // Drop stale tombstones.
+  await db.execute("DELETE FROM moz_bookmarks_deleted");
+}
+
+/**
+ * Other clients might have new fields we don't quite understand yet,
+ * so we add it to a "unknownFields" field to roundtrip back to the server
+ * so other clients don't experience data loss
+ * @param record: an object, usually from the server, and will iterate through the
+ *  the keys and extract any fields that are unknown to this client
+ * @param validFields: an array of keys we know are valid and should ignore
+ * @returns {String} json object containing unknownfields, null if none found
+ */
+PlacesSyncUtils.extractUnknownFields = (record, validFields) => {
+  let { unknownFields, hasUnknownFields } = Object.keys(record).reduce(
+    ({ unknownFields, hasUnknownFields }, key) => {
+      if (validFields.includes(key)) {
+        return { unknownFields, hasUnknownFields };
+      }
+      unknownFields[key] = record[key];
+      return { unknownFields, hasUnknownFields: true };
+    },
+    { unknownFields: {}, hasUnknownFields: false }
+  );
+  if (hasUnknownFields) {
+    // For simplicity, we store the unknown fields as a string
+    // since we never operate on it and just need it for roundtripping
+    return JSON.stringify(unknownFields);
+  }
+  return null;
+};
diff --git a/toolkit/components/places/PlacesTransactions.sys.mjs b/toolkit/components/places/PlacesTransactions.sys.mjs
new file mode 100644
index 0000000000..0c9accd3ba
--- /dev/null
+++ b/toolkit/components/places/PlacesTransactions.sys.mjs
@@ -0,0 +1,1803 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Overview
+ * --------
+ * This modules serves as the transactions manager for Places (hereinafter PTM).
+ * It implements all the elementary transactions for its UI commands: creating
+ * items, editing their various properties, and so forth.
+ *
+ * Note that since the effect of invoking a Places command is not limited to the
+ * window in which it was performed (e.g. a folder created in the Library may be
+ * the parent of a bookmark created in some browser window), PTM is a singleton.
+ * It's therefore unnecessary to initialize PTM in any way apart importing this
+ * module.
+ *
+ * PTM shares most of its semantics with common command pattern implementations.
+ * However, the asynchronous design of contemporary and future APIs, combined
+ * with the commitment to serialize all UI operations, does make things a little
+ * bit different.  For example, when |undo| is called in order to undo the top
+ * undo entry, the caller cannot tell for sure what entry would it be, because
+ * the execution of some transactions is either in process, or enqueued to be.
+ *
+ * Also note that unlike the nsITransactionManager, for example, this API is by
+ * no means generic.  That is, it cannot be used to execute anything but the
+ * elementary transactions implemented here (Please file a bug if you find
+ * anything uncovered).  More-complex transactions (e.g. creating a folder and
+ * moving a bookmark into it) may be implemented as a batch (see below).
+ *
+ * A note about GUIDs and item-ids
+ * -------------------------------
+ * There's an ongoing effort (see bug 1071511) to deprecate item-ids in Places
+ * in favor of GUIDs.  Both because new APIs (e.g. Bookmark.jsm) expose them to
+ * the minimum necessary, and because GUIDs play much better with implementing
+ * |redo|, this API doesn't support item-ids at all, and only accepts bookmark
+ * GUIDs, both for input (e.g. for setting the parent folder for a new bookmark)
+ * and for output (when the GUID for such a bookmark is propagated).
+ *
+ * Constructing transactions
+ * -------------------------
+ * At the bottom of this module you will find transactions for all Places UI
+ * commands.  They are exposed as constructors set on the PlacesTransactions
+ * object (e.g. PlacesTransactions.NewFolder).  The input for this constructors
+ * is taken in the form of a single argument, a plain object consisting of the
+ * properties for the transaction.  Input properties may be either required or
+ * optional (for example, |keyword| is required for the EditKeyword transaction,
+ * but optional for the NewBookmark transaction).
+ *
+ * To make things simple, a given input property has the same basic meaning and
+ * valid values across all transactions which accept it in the input object.
+ * Here is a list of all supported input properties along with their expected
+ * values:
+ *  - url: a URL object, an nsIURI object, or a href.
+ *  - urls: an array of urls, as above.
+ *  - tag - a string.
+ *  - tags: an array of strings.
+ *  - guid, parentGuid, newParentGuid: a valid Places GUID string.
+ *  - guids: an array of valid Places GUID strings.
+ *  - title: a string
+ *  - index, newIndex: the position of an item in its containing folder,
+ *    starting from 0.
+ *    integer and PlacesUtils.bookmarks.DEFAULT_INDEX
+ *
+ * If a required property is missing in the input object (e.g. not specifying
+ * parentGuid for NewBookmark), or if the value for any of the input properties
+ * is invalid "on the surface" (e.g. a numeric value for GUID, or a string that
+ * isn't 12-characters long), the transaction constructor throws right way.
+ * More complex errors (e.g. passing a non-existent GUID for parentGuid) only
+ * reveal once the transaction is executed.
+ *
+ * Executing Transactions (the |transact| method of transactions)
+ * --------------------------------------------------------------
+ * Once a transaction is created, you must call its |transact| method for it to
+ * be executed and take effect.  |transact| is an asynchronous method that takes
+ * no arguments, and returns a promise that resolves once the transaction is
+ * executed.  Executing one of the transactions for creating items (NewBookmark,
+ * NewFolder, NewSeparator) resolve to the new item's GUID.
+ * There's no resolution value for other transactions.
+ * If a transaction fails to execute, |transact| rejects and the transactions
+ * history is not affected.
+ *
+ * |transact| throws if it's called more than once (successfully or not) on the
+ * same transaction object.
+ *
+ * Batches
+ * -------
+ * Sometimes it is useful to "batch" or "merge" transactions.  For example,
+ * something like "Bookmark All Tabs" may be implemented as one NewFolder
+ * transaction followed by numerous NewBookmark transactions - all to be undone
+ * or redone in a single undo or redo command.  Use `PlacesTransactions.batch()`
+ * in such cases.
+ * It takes an array of transactions which will be executed in the given order
+ * and later be treated as a single entry in the transactions history.
+ * If a transaction depends on the results from a previous one, it can be
+ * replaced by a function that will be invoked with an array of results
+ * accumulated from the previous transactions, indexed in the same positions.
+ * The function should return the transaction to execute. For example:
+ *
+ *  let transactions = [
+ *    // Returns the GUID of the new bookmark.
+ *    PlacesTransactions.NewBookmark({
+ *      parentGuid: "someGUID",
+ *      title: "someTitle",
+ *      url: "https://www.mozilla.org/""
+ *    }),
+ *    previousResults => PlacesTransactions.EditKeyword({
+ *      // Get the GUID from the result of transactions[0].
+ *      guid: previousResults[0],
+ *      keyword: "someKeyword",
+ *    },
+ *  ];
+ *
+ * `PlacesTransactions.batch()` returns a promise resolved when the batch ends.
+ * The resolution value is an array with all the transaction return values
+ * indexed like the original transactions. So, for example, if a transaction
+ * returns an array of GUIDs, to get a list of all the created GUIDs for all the
+ * transactions one could use .flat() to flatten the array.
+ *
+ * If any transactions fails to execute, the batch continues (exceptions are
+ * logged) and the result of that transactions will be set to undefined.
+ * Only transactions that were executed successfully are added to the
+ * transactions history as part of the batch.
+ *
+ * Serialization
+ * -------------
+ * All |PlacesTransaction| operations are serialized.  That is, even though the
+ * implementation is asynchronous, the order in which PlacesTransactions methods
+ * is called does guarantee the order in which they are to be invoked.
+ *
+ * The only exception to this rule is |transact| calls done during a batch (see
+ * above).  |transact| calls are serialized with each other (and with undo, redo
+ * and clearTransactionsHistory), but they  are, of course, not serialized with
+ * batches.
+ *
+ * The transactions-history structure
+ * ----------------------------------
+ * The transactions-history is a two-dimensional stack of transactions: the
+ * transactions are ordered in reverse to the order they were committed.
+ * It's two-dimensional because PTM allows batching transactions together for
+ * the purpose of undo or redo (see Batches above).
+ *
+ * The undoPosition property is set to the index of the top entry. If there is
+ * no entry at that index, there is nothing to undo.
+ * Entries prior to undoPosition, if any, are redo entries, the first one being
+ * the top redo entry.
+ *
+ * [ [2nd redo txn, 1st redo txn],  <= 2nd redo entry
+ *   [2nd redo txn, 1st redo txn],  <= 1st redo entry
+ *   [1st undo txn, 2nd undo txn],  <= 1st undo entry
+ *   [1st undo txn, 2nd undo txn]   <= 2nd undo entry ]
+ * undoPostion: 2.
+ *
+ * Note that when a new entry is created, all redo entries are removed.
+ */
+
+const TRANSACTIONS_QUEUE_TIMEOUT_MS = 240000; // 4 Mins.
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+// Use a single queue bookmarks transaction manager. This pref exists as an
+// emergency switch-off, it will go away in the future.
+const prefs = {};
+XPCOMUtils.defineLazyPreferenceGetter(
+  prefs,
+  "USE_SINGLE_QUEUE",
+  "places.bookmarks.useSingleQueueTransactionManager",
+  true
+);
+
+import { PlacesUtils } from "resource://gre/modules/PlacesUtils.sys.mjs";
+
+function setTimeout(callback, ms) {
+  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+  timer.initWithCallback(callback, ms, timer.TYPE_ONE_SHOT);
+}
+
+const lazy = {};
+ChromeUtils.defineLazyGetter(lazy, "logger", function () {
+  return console.createInstance({
+    prefix: "PlacesTransactions",
+    maxLogLevel: Services.prefs.getCharPref(
+      "places.transactions.logLevel",
+      "Error"
+    ),
+  });
+});
+
+class TransactionsHistoryArray extends Array {
+  constructor() {
+    super();
+
+    // The index of the first undo entry (if any) - See the documentation
+    // at the top of this file.
+    this._undoPosition = 0;
+    // Outside of this module, the API of transactions is inaccessible, and so
+    // are any internal properties.  To achieve that, transactions are proxified
+    // in their constructors.  This maps the proxies to their respective raw
+    // objects.
+    this.proxifiedToRaw = new WeakMap();
+  }
+
+  get undoPosition() {
+    return this._undoPosition;
+  }
+
+  // Handy shortcuts
+  get topUndoEntry() {
+    return this.undoPosition < this.length ? this[this.undoPosition] : null;
+  }
+  get topRedoEntry() {
+    return this.undoPosition > 0 ? this[this.undoPosition - 1] : null;
+  }
+
+  /**
+   * Proxify a transaction object for consumers.
+   * @param rawTransaction
+   *        the raw transaction object.
+   * @return the proxified transaction object.
+   * @see getRawTransaction for retrieving the raw transaction.
+   */
+  proxifyTransaction(rawTransaction) {
+    let proxy = Object.freeze({
+      transact(inBatch, batchIndex) {
+        return TransactionsManager.transact(this, inBatch, batchIndex);
+      },
+      toString() {
+        return rawTransaction.toString();
+      },
+    });
+    this.proxifiedToRaw.set(proxy, rawTransaction);
+    return proxy;
+  }
+
+  /**
+   * Check if the given object is a the proxy object for some transaction.
+   * @param aValue
+   *        any JS value.
+   * @return true if aValue is the proxy object for some transaction, false
+   * otherwise.
+   */
+  isProxifiedTransactionObject(value) {
+    return this.proxifiedToRaw.has(value);
+  }
+
+  /**
+   * Get the raw transaction for the given proxy.
+   * @param aProxy
+   *        the proxy object
+   * @return the transaction proxified by aProxy; |undefined| is returned if
+   * aProxy is not a proxified transaction.
+   */
+  getRawTransaction(proxy) {
+    return this.proxifiedToRaw.get(proxy);
+  }
+
+  /**
+   * Add a transaction either as a new entry, if forced or if there are no undo
+   * entries, or to the top undo entry.
+   *
+   * @param aProxifiedTransaction
+   *        the proxified transaction object to be added to the transaction
+   *        history.
+   * @param [optional] aForceNewEntry
+   *        Force a new entry for the transaction. Default: false.
+   *        If false, an entry will we created only if there's no undo entry
+   *        to extend.
+   */
+  add(proxifiedTransaction, forceNewEntry = false) {
+    if (!this.isProxifiedTransactionObject(proxifiedTransaction)) {
+      throw new Error("aProxifiedTransaction is not a proxified transaction");
+    }
+
+    if (!this.length || forceNewEntry) {
+      this.clearRedoEntries();
+      lazy.logger.debug(`Adding transaction: ${proxifiedTransaction}`);
+      this.unshift([proxifiedTransaction]);
+    } else {
+      lazy.logger.debug(`Adding transaction: ${proxifiedTransaction}`);
+      this[this.undoPosition].unshift(proxifiedTransaction);
+    }
+  }
+
+  /**
+   * Clear all undo entries.
+   */
+  clearUndoEntries() {
+    lazy.logger.debug("Clearing undo entries");
+    if (this.undoPosition < this.length) {
+      this.splice(this.undoPosition);
+    }
+  }
+
+  /**
+   * Clear all redo entries.
+   */
+  clearRedoEntries() {
+    lazy.logger.debug("Clearing redo entries");
+    if (this.undoPosition > 0) {
+      this.splice(0, this.undoPosition);
+      this._undoPosition = 0;
+    }
+  }
+
+  /**
+   * Clear all entries.
+   */
+  clearAllEntries() {
+    lazy.logger.debug("Clearing all entries");
+    if (this.length) {
+      this.splice(0);
+      this._undoPosition = 0;
+    }
+  }
+}
+
+ChromeUtils.defineLazyGetter(
+  lazy,
+  "TransactionsHistory",
+  () => new TransactionsHistoryArray()
+);
+
+export var PlacesTransactions = {
+  /**
+   * @see Batches in the module documentation.
+   */
+  batch(transactionsToBatch, batchName) {
+    if (!Array.isArray(transactionsToBatch) || !transactionsToBatch.length) {
+      throw new Error("Must pass a non-empty array");
+    }
+    if (
+      transactionsToBatch.some(
+        o =>
+          !lazy.TransactionsHistory.isProxifiedTransactionObject(o) &&
+          typeof o != "function"
+      )
+    ) {
+      throw new Error("Must pass only transactions or functions");
+    }
+    lazy.logger.debug(
+      `Batch ${batchName}: ${transactionsToBatch.length} transactions`
+    );
+    return TransactionsManager.batch(async function () {
+      lazy.logger.debug(`Batch ${batchName}: executing transactions`);
+      let accumulatedResults = [];
+      for (let txn of transactionsToBatch) {
+        try {
+          if (typeof txn == "function") {
+            txn = txn(accumulatedResults);
+          }
+          accumulatedResults.push(
+            await txn.transact(true, accumulatedResults.length)
+          );
+        } catch (ex) {
+          // TODO Bug 1865631: handle these errors better, currently we just
+          // continue, that works for non-dependent transactions, but will
+          // skip most of the work for functions depending on previous results.
+          // Moreover in both cases we should notify the user about the problem.
+          accumulatedResults.push(undefined);
+          // Using console.error() here sometimes fails, due to unknown XPC
+          // wrappers reasons, so just use our logger.
+          lazy.logger.error(`Failed to execute batched transaction: ${ex}`);
+        }
+      }
+      return accumulatedResults;
+    });
+  },
+
+  /**
+   * Asynchronously undo the transaction immediately after the current undo
+   * position in the transactions history in the reverse order, if any, and
+   * adjusts the undo position.
+   *
+   * @return {Promises).  The promise always resolves.
+   * @note All undo manager operations are queued. This means that transactions
+   * history may change by the time your request is fulfilled.
+   */
+  undo() {
+    lazy.logger.debug("undo() was invoked");
+    return TransactionsManager.undo();
+  },
+
+  /**
+   * Asynchronously redo the transaction immediately before the current undo
+   * position in the transactions history, if any, and adjusts the undo
+   * position.
+   *
+   * @return {Promises).  The promise always resolves.
+   * @note All undo manager operations are queued. This means that transactions
+   * history may change by the time your request is fulfilled.
+   */
+  redo() {
+    lazy.logger.debug("redo() was invoked");
+    return TransactionsManager.redo();
+  },
+
+  /**
+   * Asynchronously clear the undo, redo, or all entries from the transactions
+   * history.
+   *
+   * @param [optional] undoEntries
+   *        Whether or not to clear undo entries.  Default: true.
+   * @param [optional] redoEntries
+   *        Whether or not to clear undo entries.  Default: true.
+   *
+   * @return {Promises).  The promise always resolves.
+   * @throws if both aUndoEntries and aRedoEntries are false.
+   * @note All undo manager operations are queued. This means that transactions
+   * history may change by the time your request is fulfilled.
+   */
+  clearTransactionsHistory(undoEntries = true, redoEntries = true) {
+    lazy.logger.debug("clearTransactionsHistory() was invoked");
+    return TransactionsManager.clearTransactionsHistory(
+      undoEntries,
+      redoEntries
+    );
+  },
+
+  /**
+   * The numbers of entries in the transactions history.
+   */
+  get length() {
+    return lazy.TransactionsHistory.length;
+  },
+
+  /**
+   * Get the transaction history entry at a given index.  Each entry consists
+   * of one or more transaction objects.
+   *
+   * @param index
+   *        the index of the entry to retrieve.
+   * @return an array of transaction objects in their undo order (that is,
+   * reversely to the order they were executed).
+   * @throw if aIndex is invalid (< 0 or >= length).
+   * @note the returned array is a clone of the history entry and is not
+   * kept in sync with the original entry if it changes.
+   */
+  entry(index) {
+    if (!Number.isInteger(index) || index < 0 || index >= this.length) {
+      throw new Error("Invalid index");
+    }
+
+    return lazy.TransactionsHistory[index];
+  },
+
+  /**
+   * The index of the top undo entry in the transactions history.
+   * If there are no undo entries, it equals to |length|.
+   * Entries past this point
+   * Entries at and past this point are redo entries.
+   */
+  get undoPosition() {
+    return lazy.TransactionsHistory.undoPosition;
+  },
+
+  /**
+   * Shortcut for accessing the top undo entry in the transaction history.
+   */
+  get topUndoEntry() {
+    return lazy.TransactionsHistory.topUndoEntry;
+  },
+
+  /**
+   * Shortcut for accessing the top redo entry in the transaction history.
+   */
+  get topRedoEntry() {
+    return lazy.TransactionsHistory.topRedoEntry;
+  },
+};
+
+/**
+ * Helper for serializing the calls to TransactionsManager methods. It allows
+ * us to guarantee that the order in which TransactionsManager asynchronous
+ * methods are called also enforces the order in which they're executed, and
+ * that they are never executed in parallel.
+ *
+ * In other words: Enqueuer.enqueue(aFunc1); Enqueuer.enqueue(aFunc2) is roughly
+ * the same as Task.spawn(aFunc1).then(Task.spawn(aFunc2)).
+ */
+function Enqueuer(name) {
+  this._promise = Promise.resolve();
+  this._name = name;
+}
+Enqueuer.prototype = {
+  /**
+   * Spawn a functions once all previous functions enqueued are done running,
+   * and all promises passed to alsoWaitFor are no longer pending.
+   *
+   * @param   func
+   *          a function returning a promise.
+   * @return  a promise that resolves once aFunc is done running. The promise
+   *          "mirrors" the promise returned by aFunc.
+   */
+  enqueue(func) {
+    lazy.logger.debug(`${this._name} enqueing`);
+    // If a transaction awaits on a never resolved promise, or is mistakenly
+    // nested, it could hang the transactions queue forever.  Thus we timeout
+    // the execution after a meaningful amount of time, to ensure in any case
+    // we'll proceed after a while.
+    let timeoutPromise = new Promise((resolve, reject) => {
+      setTimeout(
+        () =>
+          reject(
+            new Error(
+              "PlacesTransaction timeout, most likely caused by unresolved pending work."
+            )
+          ),
+        TRANSACTIONS_QUEUE_TIMEOUT_MS
+      );
+    });
+    let promise = this._promise.then(() =>
+      Promise.race([func(), timeoutPromise])
+    );
+
+    // Propagate exceptions to the caller, but dismiss them internally.
+    this._promise = promise.catch(lazy.logger.error);
+    return promise;
+  },
+
+  /**
+   * Same as above, but for a promise returned by a function that already run.
+   * This is useful, for example, for serializing transact calls with undo calls,
+   * even though transact has its own Enqueuer.
+   *
+   * @param {Promise} otherPromise
+   *        any promise.
+   * @param {string} source
+   *        source for logging purposes
+   */
+  alsoWaitFor(otherPromise, source) {
+    lazy.logger.debug(`${this._name} alsoWaitFor: ${source}`);
+    // We don't care if aPromise resolves or rejects, but just that is not
+    // pending anymore.
+    // If a transaction awaits on a never resolved promise, or is mistakenly
+    // nested, it could hang the transactions queue forever.  Thus we timeout
+    // the execution after a meaningful amount of time, to ensure in any case
+    // we'll proceed after a while.
+    let timeoutPromise = new Promise((resolve, reject) => {
+      setTimeout(
+        () =>
+          reject(
+            new Error(
+              "PlacesTransaction timeout, most likely caused by unresolved pending work."
+            )
+          ),
+        TRANSACTIONS_QUEUE_TIMEOUT_MS
+      );
+    });
+    let promise = Promise.race([otherPromise, timeoutPromise]).catch(
+      console.error
+    );
+    this._promise = Promise.all([this._promise, promise]);
+  },
+
+  /**
+   * The promise for this queue.
+   */
+  get promise() {
+    return this._promise;
+  },
+};
+
+var TransactionsManager = {
+  // See the documentation at the top of this file. |transact| calls are not
+  // serialized with |batch| calls.
+  _mainEnqueuer: new Enqueuer("MainEnqueuer"),
+  _transactEnqueuer: new Enqueuer("TransactEnqueuer"),
+
+  // Transactions object should never be recycled (that is, |execute| should
+  // only be called once (or not at all) after they're constructed.
+  // This keeps track of all transactions which were executed.
+  _executedTransactions: new WeakSet(),
+
+  /**
+   * Execute a proxified transaction.
+   *
+   * @param {object} txnProxy The proxified transaction to execute.
+   * @param {boolean} [inBatch] Whether the transaction is part of a batch.
+   * @param {integer} [batchIndex] The index of the transaction in the batch array.
+   * @returns {Promise} resolved to the transaction return value once complete.
+   */
+  transact(txnProxy, inBatch = false, batchIndex = undefined) {
+    let rawTxn = lazy.TransactionsHistory.getRawTransaction(txnProxy);
+    if (!rawTxn) {
+      throw new Error("|transact| was called with an unexpected object");
+    }
+
+    if (this._executedTransactions.has(rawTxn)) {
+      throw new Error("Transactions objects may not be recycled.");
+    }
+
+    lazy.logger.debug(`transact() enqueue: ${txnProxy}`);
+
+    // Add it in advance so one doesn't accidentally do
+    // sameTxn.transact(); sameTxn.transact();
+    this._executedTransactions.add(rawTxn);
+
+    let task = async () => {
+      lazy.logger.debug(`transact execute(): ${txnProxy}`);
+      // Don't try to catch exceptions. If execute fails, we better not add the
+      // transaction to the undo stack.
+      let retval = await rawTxn.execute();
+
+      let forceNewEntry = !inBatch || batchIndex === 0;
+      lazy.TransactionsHistory.add(txnProxy, forceNewEntry);
+
+      this._updateCommandsOnActiveWindow();
+      return retval;
+    };
+
+    if (prefs.USE_SINGLE_QUEUE) {
+      return task();
+    }
+
+    let promise = this._transactEnqueuer.enqueue(task);
+    this._mainEnqueuer.alsoWaitFor(promise, "transact");
+    return promise;
+  },
+
+  batch(task) {
+    return this._mainEnqueuer.enqueue(task);
+  },
+
+  /**
+   * Undo the top undo entry, if any, and update the undo position accordingly.
+   */
+  undo() {
+    let promise = this._mainEnqueuer.enqueue(async () => {
+      lazy.logger.debug("Undo execute");
+      let entry = lazy.TransactionsHistory.topUndoEntry;
+      if (!entry) {
+        return;
+      }
+
+      for (let txnProxy of entry) {
+        try {
+          await lazy.TransactionsHistory.getRawTransaction(txnProxy).undo();
+        } catch (ex) {
+          // If one transaction is broken, it's not safe to work with any other
+          // undo entry.  Report the error and clear the undo history.
+          console.error(ex, "Can't undo a transaction, clearing undo entries.");
+          lazy.TransactionsHistory.clearUndoEntries();
+          return;
+        }
+      }
+      lazy.TransactionsHistory._undoPosition++;
+      this._updateCommandsOnActiveWindow();
+    });
+    if (!prefs.USE_SINGLE_QUEUE) {
+      this._transactEnqueuer.alsoWaitFor(promise, "undo");
+    }
+    return promise;
+  },
+
+  /**
+   * Redo the top redo entry, if any, and update the undo position accordingly.
+   */
+  redo() {
+    let promise = this._mainEnqueuer.enqueue(async () => {
+      lazy.logger.debug("Redo execute");
+      let entry = lazy.TransactionsHistory.topRedoEntry;
+      if (!entry) {
+        return;
+      }
+
+      for (let i = entry.length - 1; i >= 0; i--) {
+        let transaction = lazy.TransactionsHistory.getRawTransaction(entry[i]);
+        try {
+          if (transaction.redo) {
+            await transaction.redo();
+          } else {
+            await transaction.execute();
+          }
+        } catch (ex) {
+          // If one transaction is broken, it's not safe to work with any other
+          // redo entry. Report the error and clear the undo history.
+          console.error(ex, "Can't redo a transaction, clearing redo entries.");
+          lazy.TransactionsHistory.clearRedoEntries();
+          return;
+        }
+      }
+      lazy.TransactionsHistory._undoPosition--;
+      this._updateCommandsOnActiveWindow();
+    });
+    if (!prefs.USE_SINGLE_QUEUE) {
+      this._transactEnqueuer.alsoWaitFor(promise, "redo");
+    }
+    return promise;
+  },
+
+  clearTransactionsHistory(undoEntries, redoEntries) {
+    let promise = this._mainEnqueuer.enqueue(function () {
+      lazy.logger.debug(`ClearTransactionsHistory execute`);
+      if (undoEntries && redoEntries) {
+        lazy.TransactionsHistory.clearAllEntries();
+      } else if (undoEntries) {
+        lazy.TransactionsHistory.clearUndoEntries();
+      } else if (redoEntries) {
+        lazy.TransactionsHistory.clearRedoEntries();
+      } else {
+        throw new Error("either aUndoEntries or aRedoEntries should be true");
+      }
+    });
+
+    if (!prefs.USE_SINGLE_QUEUE) {
+      this._transactEnqueuer.alsoWaitFor(promise, "clearTransactionsHistory");
+    }
+    return promise;
+  },
+
+  // Updates commands in the undo group of the active window commands.
+  // Inactive windows commands will be updated on focus.
+  _updateCommandsOnActiveWindow() {
+    // Updating "undo" will cause a group update including "redo".
+    try {
+      let win = Services.focus.activeWindow;
+      if (win) {
+        win.updateCommands("undo");
+      }
+    } catch (ex) {
+      console.error(ex, "Couldn't update undo commands.");
+    }
+  },
+};
+
+/**
+ * Internal helper for defining the standard transactions and their input.
+ * It takes the required and optional properties, and generates the public
+ * constructor (which takes the input in the form of a plain object) which,
+ * when called, creates the argument-less "public" |execute| method by binding
+ * the input properties to the function arguments (required properties first,
+ * then the optional properties).
+ *
+ * If this seems confusing, look at the consumers.
+ *
+ * This magic serves two purposes:
+ * (1) It completely hides the transactions' internals from the module
+ *     consumers.
+ * (2) It keeps each transaction implementation to what is about, bypassing
+ *     all this bureaucracy while still validating input appropriately.
+ */
+function DefineTransaction(requiredProps = [], optionalProps = []) {
+  for (let prop of [...requiredProps, ...optionalProps]) {
+    if (!DefineTransaction.inputProps.has(prop)) {
+      throw new Error("Property '" + prop + "' is not defined");
+    }
+  }
+
+  let ctor = function (input) {
+    // We want to support both syntaxes:
+    // let t = new PlacesTransactions.NewBookmark(),
+    // let t = PlacesTransactions.NewBookmark()
+    if (this == PlacesTransactions) {
+      return new ctor(input);
+    }
+
+    if (requiredProps.length || optionalProps.length) {
+      // Bind the input properties to the arguments of execute.
+      input = DefineTransaction.verifyInput(
+        input,
+        requiredProps,
+        optionalProps
+      );
+      this.execute = this.execute.bind(this, input);
+    }
+    return lazy.TransactionsHistory.proxifyTransaction(this);
+  };
+  return ctor;
+}
+
+function simpleValidateFunc(checkFn) {
+  return v => {
+    if (!checkFn(v)) {
+      throw new Error("Invalid value");
+    }
+    return v;
+  };
+}
+
+DefineTransaction.strValidate = simpleValidateFunc(v => typeof v == "string");
+DefineTransaction.strOrNullValidate = simpleValidateFunc(
+  v => typeof v == "string" || v === null
+);
+DefineTransaction.indexValidate = simpleValidateFunc(
+  v => Number.isInteger(v) && v >= PlacesUtils.bookmarks.DEFAULT_INDEX
+);
+DefineTransaction.guidValidate = simpleValidateFunc(v =>
+  /^[a-zA-Z0-9\-_]{12}$/.test(v)
+);
+
+function isPrimitive(v) {
+  return v === null || (typeof v != "object" && typeof v != "function");
+}
+
+function checkProperty(obj, prop, required, checkFn) {
+  if (prop in obj) {
+    return checkFn(obj[prop]);
+  }
+
+  return !required;
+}
+
+DefineTransaction.childObjectValidate = function (obj) {
+  if (
+    obj &&
+    checkProperty(obj, "title", false, v => typeof v == "string") &&
+    !("type" in obj && obj.type != PlacesUtils.bookmarks.TYPE_BOOKMARK)
+  ) {
+    obj.url = DefineTransaction.urlValidate(obj.url);
+    let validKeys = ["title", "url"];
+    if (Object.keys(obj).every(k => validKeys.includes(k))) {
+      return obj;
+    }
+  }
+  throw new Error("Invalid child object");
+};
+
+DefineTransaction.urlValidate = function (url) {
+  if (url instanceof Ci.nsIURI) {
+    return URL.fromURI(url);
+  }
+  return new URL(url);
+};
+
+DefineTransaction.inputProps = new Map();
+DefineTransaction.defineInputProps = function (
+  names,
+  validateFn,
+  defaultValue
+) {
+  for (let name of names) {
+    this.inputProps.set(name, {
+      validateValue(value) {
+        if (value === undefined) {
+          return defaultValue;
+        }
+        try {
+          return validateFn(value);
+        } catch (ex) {
+          throw new Error(`Invalid value for input property ${name}: ${ex}`);
+        }
+      },
+
+      validateInput(input, required) {
+        if (required && !(name in input)) {
+          throw new Error(`Required input property is missing: ${name}`);
+        }
+        return this.validateValue(input[name]);
+      },
+
+      isArrayProperty: false,
+    });
+  }
+};
+
+DefineTransaction.defineArrayInputProp = function (name, basePropertyName) {
+  let baseProp = this.inputProps.get(basePropertyName);
+  if (!baseProp) {
+    throw new Error(`Unknown input property: ${basePropertyName}`);
+  }
+
+  this.inputProps.set(name, {
+    validateValue(aValue) {
+      if (aValue == undefined) {
+        return [];
+      }
+
+      if (!Array.isArray(aValue)) {
+        throw new Error(`${name} input property value must be an array`);
+      }
+
+      // We must create a new array in the local scope to avoid a memory leak due
+      // to the array global object. We can't use Cu.cloneInto as that doesn't
+      // handle the URIs. Slice & map also aren't good enough, so we start off
+      // with a clean array and insert what we need into it.
+      let newArray = [];
+      for (let item of aValue) {
+        newArray.push(baseProp.validateValue(item));
+      }
+      return newArray;
+    },
+
+    // We allow setting either the array property itself (e.g. urls), or a
+    // single element of it (url, in that example), that is then transformed
+    // into a single-element array.
+    validateInput(input, required) {
+      if (name in input) {
+        // It's not allowed to set both though.
+        if (basePropertyName in input) {
+          throw new Error(`It is not allowed to set both ${name} and
+                          ${basePropertyName} as  input properties`);
+        }
+        let array = this.validateValue(input[name]);
+        if (required && !array.length) {
+          throw new Error(`Empty array passed for required input property:
+                           ${name}`);
+        }
+        return array;
+      }
+      // If the property is required and it's not set as is, check if the base
+      // property is set.
+      if (required && !(basePropertyName in input)) {
+        throw new Error(`Required input property is missing: ${name}`);
+      }
+
+      if (basePropertyName in input) {
+        return [baseProp.validateValue(input[basePropertyName])];
+      }
+
+      return [];
+    },
+
+    isArrayProperty: true,
+  });
+};
+
+DefineTransaction.validatePropertyValue = function (prop, input, required) {
+  return this.inputProps.get(prop).validateInput(input, required);
+};
+
+DefineTransaction.getInputObjectForSingleValue = function (
+  input,
+  requiredProps,
+  optionalProps
+) {
+  // The following input forms may be deduced from a single value:
+  // * a single required property with or without optional properties (the given
+  //   value is set to the required property).
+  // * a single optional property with no required properties.
+  if (
+    requiredProps.length > 1 ||
+    (!requiredProps.length && optionalProps.length > 1)
+  ) {
+    throw new Error("Transaction input isn't an object");
+  }
+
+  let propName =
+    requiredProps.length == 1 ? requiredProps[0] : optionalProps[0];
+  let propValue =
+    this.inputProps.get(propName).isArrayProperty && !Array.isArray(input)
+      ? [input]
+      : input;
+  return { [propName]: propValue };
+};
+
+DefineTransaction.verifyInput = function (
+  input,
+  requiredProps = [],
+  optionalProps = []
+) {
+  if (!requiredProps.length && !optionalProps.length) {
+    return {};
+  }
+
+  // If there's just a single required/optional property, we allow passing it
+  // as is, so, for example, one could do PlacesTransactions.Remove(myGuid)
+  // rather than PlacesTransactions.Remove({ guid: myGuid}).
+  // This shortcut isn't supported for "complex" properties, like objects (note
+  // there is no use case for this at the moment anyway).
+  let isSinglePropertyInput =
+    isPrimitive(input) ||
+    Array.isArray(input) ||
+    input instanceof Ci.nsISupports;
+  if (isSinglePropertyInput) {
+    input = this.getInputObjectForSingleValue(
+      input,
+      requiredProps,
+      optionalProps
+    );
+  }
+
+  let fixedInput = {};
+  for (let prop of requiredProps) {
+    fixedInput[prop] = this.validatePropertyValue(prop, input, true);
+  }
+  for (let prop of optionalProps) {
+    fixedInput[prop] = this.validatePropertyValue(prop, input, false);
+  }
+
+  return fixedInput;
+};
+
+// Update the documentation at the top of this module if you add or
+// remove properties.
+DefineTransaction.defineInputProps(
+  ["url"],
+  DefineTransaction.urlValidate,
+  null
+);
+DefineTransaction.defineInputProps(
+  ["guid", "parentGuid", "newParentGuid"],
+  DefineTransaction.guidValidate
+);
+DefineTransaction.defineInputProps(
+  ["title", "postData"],
+  DefineTransaction.strOrNullValidate,
+  null
+);
+DefineTransaction.defineInputProps(
+  ["keyword", "oldKeyword", "oldTag", "tag"],
+  DefineTransaction.strValidate,
+  ""
+);
+DefineTransaction.defineInputProps(
+  ["index", "newIndex"],
+  DefineTransaction.indexValidate,
+  PlacesUtils.bookmarks.DEFAULT_INDEX
+);
+DefineTransaction.defineInputProps(
+  ["child"],
+  DefineTransaction.childObjectValidate
+);
+DefineTransaction.defineArrayInputProp("guids", "guid");
+DefineTransaction.defineArrayInputProp("urls", "url");
+DefineTransaction.defineArrayInputProp("tags", "tag");
+DefineTransaction.defineArrayInputProp("children", "child");
+
+/**
+ * Creates items (all types) from a bookmarks tree representation, as defined
+ * in PlacesUtils.promiseBookmarksTree.
+ *
+ * @param tree
+ *        the bookmarks tree object.  You may pass either a bookmarks tree
+ *        returned by promiseBookmarksTree, or a manually defined one.
+ * @param [optional] restoring (default: false)
+ *        Whether or not the items are restored.  Only in restore mode, are
+ *        the guid, dateAdded and lastModified properties honored.
+ * @note the id, root and charset properties of items in aBookmarksTree are
+ *       always ignored.  The index property is ignored for all items but the
+ *       root one.
+ * @return {Promise}
+ * @resolves to the guid of the new item.
+ */
+// TODO: Replace most of this with insertTree.
+function createItemsFromBookmarksTree(tree, restoring = false) {
+  async function createItem(
+    item,
+    parentGuid,
+    index = PlacesUtils.bookmarks.DEFAULT_INDEX
+  ) {
+    let guid;
+    let info = { parentGuid, index };
+    if (restoring) {
+      info.guid = item.guid;
+      info.dateAdded = PlacesUtils.toDate(item.dateAdded);
+      info.lastModified = PlacesUtils.toDate(item.lastModified);
+    }
+    let shouldResetLastModified = false;
+    switch (item.type) {
+      case PlacesUtils.TYPE_X_MOZ_PLACE: {
+        info.url = item.uri;
+        if (typeof item.title == "string") {
+          info.title = item.title;
+        }
+
+        guid = (await PlacesUtils.bookmarks.insert(info)).guid;
+
+        if ("keyword" in item) {
+          let { uri: url, keyword, postData } = item;
+          await PlacesUtils.keywords.insert({ url, keyword, postData });
+        }
+        if ("tags" in item) {
+          PlacesUtils.tagging.tagURI(
+            Services.io.newURI(item.uri),
+            item.tags.split(",")
+          );
+        }
+        break;
+      }
+      case PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER: {
+        info.type = PlacesUtils.bookmarks.TYPE_FOLDER;
+        if (typeof item.title == "string") {
+          info.title = item.title;
+        }
+        guid = (await PlacesUtils.bookmarks.insert(info)).guid;
+        if ("children" in item) {
+          for (let child of item.children) {
+            await createItem(child, guid);
+          }
+        }
+        if (restoring) {
+          shouldResetLastModified = true;
+        }
+        break;
+      }
+      case PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR: {
+        info.type = PlacesUtils.bookmarks.TYPE_SEPARATOR;
+        guid = (await PlacesUtils.bookmarks.insert(info)).guid;
+        break;
+      }
+    }
+
+    if (shouldResetLastModified) {
+      let lastModified = PlacesUtils.toDate(item.lastModified);
+      await PlacesUtils.bookmarks.update({ guid, lastModified });
+    }
+
+    return guid;
+  }
+  return createItem(tree, tree.parentGuid, tree.index);
+}
+
+/** ***************************************************************************
+ * The Standard Places Transactions.
+ *
+ * See the documentation at the top of this file. The valid values for input
+ * are also documented there.
+ *****************************************************************************/
+
+var PT = PlacesTransactions;
+
+/**
+ * Transaction for creating a bookmark.
+ *
+ * Required Input Properties: url, parentGuid.
+ * Optional Input Properties: index, title, keyword, tags.
+ *
+ * When this transaction is executed, it's resolved to the new bookmark's GUID.
+ */
+PT.NewBookmark = DefineTransaction(
+  ["parentGuid", "url"],
+  ["index", "title", "tags"]
+);
+PT.NewBookmark.prototype = Object.seal({
+  async execute({ parentGuid, url, index, title, tags }) {
+    let info = { parentGuid, index, url, title };
+    // Filter tags to exclude already existing ones.
+    if (tags.length) {
+      let currentTags = PlacesUtils.tagging.getTagsForURI(url.URI);
+      tags = tags.filter(t => !currentTags.includes(t));
+    }
+
+    async function createItem() {
+      info = await PlacesUtils.bookmarks.insert(info);
+      if (tags.length) {
+        PlacesUtils.tagging.tagURI(url.URI, tags);
+      }
+    }
+
+    await createItem();
+
+    this.undo = async function () {
+      // Pick up the removed info so we have the accurate last-modified value.
+      await PlacesUtils.bookmarks.remove(info);
+      if (tags.length) {
+        PlacesUtils.tagging.untagURI(url.URI, tags);
+      }
+    };
+    this.redo = async function () {
+      await createItem();
+    };
+    return info.guid;
+  },
+  toString() {
+    return "NewBookmark";
+  },
+});
+
+/**
+ * Transaction for creating a folder.
+ *
+ * Required Input Properties: title, parentGuid.
+ * Optional Input Properties: index, children
+ *
+ * When this transaction is executed, it's resolved to the new folder's GUID.
+ */
+PT.NewFolder = DefineTransaction(
+  ["parentGuid", "title"],
+  ["index", "children"]
+);
+PT.NewFolder.prototype = Object.seal({
+  async execute({ parentGuid, title, index, children }) {
+    let folderGuid;
+    let info = {
+      children: [
+        {
+          // Ensure to specify a guid to be restored on redo.
+          guid: PlacesUtils.history.makeGuid(),
+          title,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        },
+      ],
+      // insertTree uses guid as the parent for where it is being inserted
+      // into.
+      guid: parentGuid,
+    };
+
+    if (children && children.length) {
+      // Ensure to specify a guid for each child to be restored on redo.
+      info.children[0].children = children.map(c => {
+        c.guid = PlacesUtils.history.makeGuid();
+        return c;
+      });
+    }
+
+    async function createItem() {
+      // Note, insertTree returns an array, rather than the folder/child structure.
+      // For simplicity, we only get the new folder id here. This means that
+      // an undo then redo won't retain exactly the same information for all
+      // the child bookmarks, but we believe that isn't important at the moment.
+      let bmInfo = await PlacesUtils.bookmarks.insertTree(info);
+      // insertTree returns an array, but we only need to deal with the folder guid.
+      folderGuid = bmInfo[0].guid;
+
+      // Bug 1388097: insertTree doesn't handle inserting at a specific index for the folder,
+      // therefore we update the bookmark manually afterwards.
+      if (index != PlacesUtils.bookmarks.DEFAULT_INDEX) {
+        bmInfo[0].index = index;
+        bmInfo = await PlacesUtils.bookmarks.update(bmInfo[0]);
+      }
+    }
+    await createItem();
+
+    this.undo = async function () {
+      await PlacesUtils.bookmarks.remove(folderGuid);
+    };
+    this.redo = async function () {
+      await createItem();
+    };
+    return folderGuid;
+  },
+  toString() {
+    return "NewFolder";
+  },
+});
+
+/**
+ * Transaction for creating a separator.
+ *
+ * Required Input Properties: parentGuid.
+ * Optional Input Properties: index.
+ *
+ * When this transaction is executed, it's resolved to the new separator's
+ * GUID.
+ */
+PT.NewSeparator = DefineTransaction(["parentGuid"], ["index"]);
+PT.NewSeparator.prototype = Object.seal({
+  async execute(info) {
+    info.type = PlacesUtils.bookmarks.TYPE_SEPARATOR;
+    info = await PlacesUtils.bookmarks.insert(info);
+    this.undo = PlacesUtils.bookmarks.remove.bind(PlacesUtils.bookmarks, info);
+    this.redo = PlacesUtils.bookmarks.insert.bind(PlacesUtils.bookmarks, info);
+    return info.guid;
+  },
+  toString() {
+    return "NewSeparator";
+  },
+});
+
+/**
+ * Transaction for moving an item.
+ *
+ * Required Input Properties: guid, newParentGuid.
+ * Optional Input Properties  newIndex.
+ */
+PT.Move = DefineTransaction(["guids", "newParentGuid"], ["newIndex"]);
+PT.Move.prototype = Object.seal({
+  async execute({ guids, newParentGuid, newIndex }) {
+    let originalInfos = [];
+    let index = newIndex;
+
+    for (let guid of guids) {
+      // We need to save the original data for undo.
+      let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
+      if (!originalInfo) {
+        throw new Error("Cannot move a non-existent item");
+      }
+
+      originalInfos.push(originalInfo);
+    }
+
+    await PlacesUtils.bookmarks.moveToFolder(guids, newParentGuid, index);
+
+    this.undo = async function () {
+      // Undo has the potential for moving multiple bookmarks to multiple different
+      // folders and positions, which is very complicated to manage. Therefore we do
+      // individual moves one at a time and hopefully everything is put back approximately
+      // where it should be.
+      for (let info of originalInfos) {
+        await PlacesUtils.bookmarks.update(info);
+      }
+    };
+    this.redo = PlacesUtils.bookmarks.moveToFolder.bind(
+      PlacesUtils.bookmarks,
+      guids,
+      newParentGuid,
+      index
+    );
+    return guids;
+  },
+  toString() {
+    return "Move";
+  },
+});
+
+/**
+ * Transaction for setting the title for an item.
+ *
+ * Required Input Properties: guid, title.
+ */
+PT.EditTitle = DefineTransaction(["guid", "title"]);
+PT.EditTitle.prototype = Object.seal({
+  async execute({ guid, title }) {
+    let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
+    if (!originalInfo) {
+      throw new Error("cannot update a non-existent item");
+    }
+
+    let updateInfo = { guid, title };
+    updateInfo = await PlacesUtils.bookmarks.update(updateInfo);
+
+    this.undo = PlacesUtils.bookmarks.update.bind(
+      PlacesUtils.bookmarks,
+      originalInfo
+    );
+    this.redo = PlacesUtils.bookmarks.update.bind(
+      PlacesUtils.bookmarks,
+      updateInfo
+    );
+  },
+  toString() {
+    return "EditTitle";
+  },
+});
+
+/**
+ * Transaction for setting the URI for an item.
+ *
+ * Required Input Properties: guid, url.
+ */
+PT.EditUrl = DefineTransaction(["guid", "url"]);
+PT.EditUrl.prototype = Object.seal({
+  async execute({ guid, url }) {
+    let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
+    if (!originalInfo) {
+      throw new Error("cannot update a non-existent item");
+    }
+    if (originalInfo.type != PlacesUtils.bookmarks.TYPE_BOOKMARK) {
+      throw new Error("Cannot edit url for non-bookmark items");
+    }
+
+    let uri = url.URI;
+    let originalURI = originalInfo.url.URI;
+    let originalTags = PlacesUtils.tagging.getTagsForURI(originalURI);
+    let updatedInfo = { guid, url };
+    let newURIAdditionalTags = null;
+
+    async function updateItem() {
+      updatedInfo = await PlacesUtils.bookmarks.update(updatedInfo);
+      // Move tags from the original URI to the new URI.
+      if (originalTags.length) {
+        // Untag the original URI only if this was the only bookmark.
+        if (!(await PlacesUtils.bookmarks.fetch({ url: originalInfo.url }))) {
+          PlacesUtils.tagging.untagURI(originalURI, originalTags);
+        }
+        let currentNewURITags = PlacesUtils.tagging.getTagsForURI(uri);
+        newURIAdditionalTags = originalTags.filter(
+          t => !currentNewURITags.includes(t)
+        );
+        if (newURIAdditionalTags && newURIAdditionalTags.length) {
+          PlacesUtils.tagging.tagURI(uri, newURIAdditionalTags);
+        }
+      }
+    }
+    await updateItem();
+
+    this.undo = async function () {
+      await PlacesUtils.bookmarks.update(originalInfo);
+      // Move tags from new URI to original URI.
+      if (originalTags.length) {
+        // Only untag the new URI if this is the only bookmark.
+        if (
+          newURIAdditionalTags &&
+          !!newURIAdditionalTags.length &&
+          !(await PlacesUtils.bookmarks.fetch({ url }))
+        ) {
+          PlacesUtils.tagging.untagURI(uri, newURIAdditionalTags);
+        }
+        PlacesUtils.tagging.tagURI(originalURI, originalTags);
+      }
+    };
+
+    this.redo = async function () {
+      updatedInfo = await updateItem();
+    };
+  },
+  toString() {
+    return "EditUrl";
+  },
+});
+
+/**
+ * Transaction for setting the keyword for a bookmark.
+ *
+ * Required Input Properties: guid, keyword.
+ * Optional Input Properties: postData, oldKeyword.
+ */
+PT.EditKeyword = DefineTransaction(
+  ["guid", "keyword"],
+  ["postData", "oldKeyword"]
+);
+PT.EditKeyword.prototype = Object.seal({
+  async execute({ guid, keyword, postData, oldKeyword }) {
+    let url;
+    let oldKeywordEntry;
+    if (oldKeyword) {
+      oldKeywordEntry = await PlacesUtils.keywords.fetch(oldKeyword);
+      url = oldKeywordEntry.url;
+      await PlacesUtils.keywords.remove(oldKeyword);
+    }
+
+    if (keyword) {
+      if (!url) {
+        url = (await PlacesUtils.bookmarks.fetch(guid)).url;
+      }
+      await PlacesUtils.keywords.insert({
+        url,
+        keyword,
+        postData: postData || (oldKeywordEntry ? oldKeywordEntry.postData : ""),
+      });
+    }
+
+    this.undo = async function () {
+      if (keyword) {
+        await PlacesUtils.keywords.remove(keyword);
+      }
+      if (oldKeywordEntry) {
+        await PlacesUtils.keywords.insert(oldKeywordEntry);
+      }
+    };
+  },
+  toString() {
+    return "EditKeyword";
+  },
+});
+
+/**
+ * Transaction for sorting a folder by name.
+ *
+ * Required Input Properties: guid.
+ */
+PT.SortByName = DefineTransaction(["guid"]);
+PT.SortByName.prototype = {
+  async execute({ guid }) {
+    let sortingMethod = (node_a, node_b) => {
+      if (
+        PlacesUtils.nodeIsContainer(node_a) &&
+        !PlacesUtils.nodeIsContainer(node_b)
+      ) {
+        return -1;
+      }
+      if (
+        !PlacesUtils.nodeIsContainer(node_a) &&
+        PlacesUtils.nodeIsContainer(node_b)
+      ) {
+        return 1;
+      }
+      return node_a.title.localeCompare(node_b.title);
+    };
+    let oldOrderGuids = [];
+    let newOrderGuids = [];
+    let preSepNodes = [];
+
+    // This is not great, since it does main-thread IO.
+    // PromiseBookmarksTree can't be used, since it' won't stop at the first level'.
+    let root = PlacesUtils.getFolderContents(guid, false, false).root;
+    for (let i = 0; i < root.childCount; ++i) {
+      let node = root.getChild(i);
+      oldOrderGuids.push(node.bookmarkGuid);
+      if (PlacesUtils.nodeIsSeparator(node)) {
+        if (preSepNodes.length) {
+          preSepNodes.sort(sortingMethod);
+          newOrderGuids.push(...preSepNodes.map(n => n.bookmarkGuid));
+          preSepNodes = [];
+        }
+        newOrderGuids.push(node.bookmarkGuid);
+      } else {
+        preSepNodes.push(node);
+      }
+    }
+    root.containerOpen = false;
+    if (preSepNodes.length) {
+      preSepNodes.sort(sortingMethod);
+      newOrderGuids.push(...preSepNodes.map(n => n.bookmarkGuid));
+    }
+    await PlacesUtils.bookmarks.reorder(guid, newOrderGuids);
+
+    this.undo = async function () {
+      await PlacesUtils.bookmarks.reorder(guid, oldOrderGuids);
+    };
+    this.redo = async function () {
+      await PlacesUtils.bookmarks.reorder(guid, newOrderGuids);
+    };
+  },
+  toString() {
+    return "SortByName";
+  },
+};
+
+/**
+ * Transaction for removing an item (any type).
+ *
+ * Required Input Properties: guids.
+ */
+PT.Remove = DefineTransaction(["guids"]);
+PT.Remove.prototype = {
+  async execute({ guids }) {
+    let removedItems = [];
+
+    for (let guid of guids) {
+      try {
+        // Although we don't strictly need to get this information for the remove,
+        // we do need it for the possibility of undo().
+        removedItems.push(await PlacesUtils.promiseBookmarksTree(guid));
+      } catch (ex) {
+        if (!ex.becauseInvalidURL) {
+          throw new Error(`Failed to get info for the guid: ${guid}: ${ex}`);
+        }
+        removedItems.push({ guid });
+      }
+    }
+
+    let removeThem = async function () {
+      if (removedItems.length) {
+        // We have to pass just the guids as although remove() accepts full
+        // info items, promiseBookmarksTree returns dateAdded and lastModified
+        // as PRTime rather than date types.
+        await PlacesUtils.bookmarks.remove(
+          removedItems.map(info => ({ guid: info.guid }))
+        );
+      }
+    };
+    await removeThem();
+
+    this.undo = async function () {
+      for (let info of removedItems) {
+        try {
+          await createItemsFromBookmarksTree(info, true);
+        } catch (ex) {
+          console.error(`Unable to undo removal of ${info.guid}`);
+        }
+      }
+    };
+    this.redo = removeThem;
+  },
+  toString() {
+    return "Remove";
+  },
+};
+
+/**
+ * Transaction for tagging urls.
+ *
+ * Required Input Properties: urls, tags.
+ */
+PT.Tag = DefineTransaction(["urls", "tags"]);
+PT.Tag.prototype = {
+  async execute({ urls, tags }) {
+    let onUndo = [],
+      onRedo = [];
+    for (let url of urls) {
+      if (!(await PlacesUtils.bookmarks.fetch({ url }))) {
+        // Tagging is only allowed for bookmarked URIs (but see 424160).
+        let createTxn = lazy.TransactionsHistory.getRawTransaction(
+          PT.NewBookmark({
+            url,
+            tags,
+            parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+          })
+        );
+        await createTxn.execute();
+        onUndo.unshift(createTxn.undo.bind(createTxn));
+        onRedo.push(createTxn.redo.bind(createTxn));
+      } else {
+        let uri = url.URI;
+        let currentTags = PlacesUtils.tagging.getTagsForURI(uri);
+        let newTags = tags.filter(t => !currentTags.includes(t));
+        if (newTags.length) {
+          PlacesUtils.tagging.tagURI(uri, newTags);
+          onUndo.unshift(() => {
+            PlacesUtils.tagging.untagURI(uri, newTags);
+          });
+          onRedo.push(() => {
+            PlacesUtils.tagging.tagURI(uri, newTags);
+          });
+        }
+      }
+    }
+    this.undo = async function () {
+      for (let f of onUndo) {
+        await f();
+      }
+    };
+    this.redo = async function () {
+      for (let f of onRedo) {
+        await f();
+      }
+    };
+  },
+  toString() {
+    return "Tag";
+  },
+};
+
+/**
+ * Transaction for removing tags from a URI.
+ *
+ * Required Input Properties: urls.
+ * Optional Input Properties: tags.
+ *
+ * If |tags| is not set, all tags set for |url| are removed.
+ */
+PT.Untag = DefineTransaction(["urls"], ["tags"]);
+PT.Untag.prototype = {
+  execute({ urls, tags }) {
+    let onUndo = [],
+      onRedo = [];
+    for (let url of urls) {
+      let uri = url.URI;
+      let tagsToRemove;
+      let tagsSet = PlacesUtils.tagging.getTagsForURI(uri);
+      if (tags.length) {
+        tagsToRemove = tags.filter(t => tagsSet.includes(t));
+      } else {
+        tagsToRemove = tagsSet;
+      }
+      if (tagsToRemove.length) {
+        PlacesUtils.tagging.untagURI(uri, tagsToRemove);
+      }
+      onUndo.unshift(() => {
+        if (tagsToRemove.length) {
+          PlacesUtils.tagging.tagURI(uri, tagsToRemove);
+        }
+      });
+      onRedo.push(() => {
+        if (tagsToRemove.length) {
+          PlacesUtils.tagging.untagURI(uri, tagsToRemove);
+        }
+      });
+    }
+    this.undo = async function () {
+      for (let f of onUndo) {
+        await f();
+      }
+    };
+    this.redo = async function () {
+      for (let f of onRedo) {
+        await f();
+      }
+    };
+  },
+  toString() {
+    return "Untag";
+  },
+};
+
+/**
+ * Transaction for renaming a tag.
+ *
+ * Required Input Properties: oldTag, tag.
+ */
+PT.RenameTag = DefineTransaction(["oldTag", "tag"]);
+PT.RenameTag.prototype = {
+  async execute({ oldTag, tag }) {
+    // For now this is implemented by untagging and tagging all the bookmarks.
+    // We should create a specialized bookmarking API to just rename the tag.
+    let onUndo = [],
+      onRedo = [];
+    let urls = new Set();
+    await PlacesUtils.bookmarks.fetch({ tags: [oldTag] }, b => urls.add(b.url));
+    if (urls.size > 0) {
+      urls = Array.from(urls);
+      let tagTxn = lazy.TransactionsHistory.getRawTransaction(
+        PT.Tag({ urls, tags: [tag] })
+      );
+      await tagTxn.execute();
+      onUndo.unshift(tagTxn.undo.bind(tagTxn));
+      onRedo.push(tagTxn.redo.bind(tagTxn));
+      let untagTxn = lazy.TransactionsHistory.getRawTransaction(
+        PT.Untag({ urls, tags: [oldTag] })
+      );
+      await untagTxn.execute();
+      onUndo.unshift(untagTxn.undo.bind(untagTxn));
+      onRedo.push(untagTxn.redo.bind(untagTxn));
+
+      // Update all the place: queries that refer to this tag.
+      let db = await PlacesUtils.promiseDBConnection();
+      let rows = await db.executeCached(
+        `
+        SELECT h.url, b.guid, b.title
+        FROM moz_places h
+        JOIN moz_bookmarks b ON b.fk = h.id
+        WHERE url_hash BETWEEN hash("place", "prefix_lo")
+                           AND hash("place", "prefix_hi")
+          AND url LIKE :tagQuery
+      `,
+        { tagQuery: "%tag=%" }
+      );
+      for (let row of rows) {
+        let url = row.getResultByName("url");
+        try {
+          url = new URL(url);
+          let urlParams = new URLSearchParams(url.pathname);
+          let tags = urlParams.getAll("tag");
+          if (!tags.includes(oldTag)) {
+            continue;
+          }
+          if (tags.length > 1) {
+            // URLSearchParams cannot set more than 1 same-named param.
+            urlParams.delete("tag");
+            urlParams.set("tag", tag);
+            url = new URL(
+              url.protocol +
+                urlParams +
+                "&tag=" +
+                tags.filter(t => t != oldTag).join("&tag=")
+            );
+          } else {
+            urlParams.set("tag", tag);
+            url = new URL(url.protocol + urlParams);
+          }
+        } catch (ex) {
+          console.error(
+            "Invalid bookmark url: " + row.getResultByName("url") + ": " + ex
+          );
+          continue;
+        }
+        let guid = row.getResultByName("guid");
+        let title = row.getResultByName("title");
+
+        let editUrlTxn = lazy.TransactionsHistory.getRawTransaction(
+          PT.EditUrl({ guid, url })
+        );
+        await editUrlTxn.execute();
+        onUndo.unshift(editUrlTxn.undo.bind(editUrlTxn));
+        onRedo.push(editUrlTxn.redo.bind(editUrlTxn));
+        if (title == oldTag) {
+          let editTitleTxn = lazy.TransactionsHistory.getRawTransaction(
+            PT.EditTitle({ guid, title: tag })
+          );
+          await editTitleTxn.execute();
+          onUndo.unshift(editTitleTxn.undo.bind(editTitleTxn));
+          onRedo.push(editTitleTxn.redo.bind(editTitleTxn));
+        }
+      }
+    }
+    this.undo = async function () {
+      for (let f of onUndo) {
+        await f();
+      }
+    };
+    this.redo = async function () {
+      for (let f of onRedo) {
+        await f();
+      }
+    };
+  },
+  toString() {
+    return "RenameTag";
+  },
+};
+
+/**
+ * Transaction for copying an item.
+ *
+ * Required Input Properties: guid, newParentGuid
+ * Optional Input Properties: newIndex.
+ */
+PT.Copy = DefineTransaction(["guid", "newParentGuid"], ["newIndex"]);
+PT.Copy.prototype = {
+  async execute({ guid, newParentGuid, newIndex }) {
+    let creationInfo = null;
+    try {
+      creationInfo = await PlacesUtils.promiseBookmarksTree(guid);
+    } catch (ex) {
+      throw new Error(
+        "Failed to get info for the specified item (guid: " +
+          guid +
+          "). Ex: " +
+          ex
+      );
+    }
+    creationInfo.parentGuid = newParentGuid;
+    creationInfo.index = newIndex;
+
+    let newItemGuid = await createItemsFromBookmarksTree(creationInfo, false);
+    let newItemInfo = null;
+    this.undo = async function () {
+      if (!newItemInfo) {
+        newItemInfo = await PlacesUtils.promiseBookmarksTree(newItemGuid);
+      }
+      await PlacesUtils.bookmarks.remove(newItemGuid);
+    };
+    this.redo = async function () {
+      await createItemsFromBookmarksTree(newItemInfo, true);
+    };
+
+    return newItemGuid;
+  },
+  toString() {
+    return "Copy";
+  },
+};
diff --git a/toolkit/components/places/PlacesUtils.sys.mjs b/toolkit/components/places/PlacesUtils.sys.mjs
new file mode 100644
index 0000000000..aeebedd31a
--- /dev/null
+++ b/toolkit/components/places/PlacesUtils.sys.mjs
@@ -0,0 +1,2923 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Bookmarks: "resource://gre/modules/Bookmarks.sys.mjs",
+  History: "resource://gre/modules/History.sys.mjs",
+  Log: "resource://gre/modules/Log.sys.mjs",
+  PlacesSyncUtils: "resource://gre/modules/PlacesSyncUtils.sys.mjs",
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "MOZ_ACTION_REGEX", () => {
+  return /^moz-action:([^,]+),(.*)$/;
+});
+
+ChromeUtils.defineLazyGetter(lazy, "CryptoHash", () => {
+  return Components.Constructor(
+    "@mozilla.org/security/hash;1",
+    "nsICryptoHash",
+    "initWithString"
+  );
+});
+
+// On Mac OSX, the transferable system converts "\r\n" to "\n\n", where
+// we really just want "\n". On other platforms, the transferable system
+// converts "\r\n" to "\n".
+const NEWLINE = AppConstants.platform == "macosx" ? "\n" : "\r\n";
+
+// Timers resolution is not always good, it can have a 16ms precision on Win.
+const TIMERS_RESOLUTION_SKEW_MS = 16;
+
+function QI_node(aNode, aIID) {
+  try {
+    return aNode.QueryInterface(aIID);
+  } catch (ex) {}
+  return null;
+}
+function asContainer(aNode) {
+  return QI_node(aNode, Ci.nsINavHistoryContainerResultNode);
+}
+function asQuery(aNode) {
+  return QI_node(aNode, Ci.nsINavHistoryQueryResultNode);
+}
+
+/**
+ * Sends a keyword change notification.
+ *
+ * @param url
+ *        the url to notify about.
+ * @param keyword
+ *        The keyword to notify, or empty string if a keyword was removed.
+ */
+async function notifyKeywordChange(url, keyword, source) {
+  // Notify bookmarks about the removal.
+  let bookmarks = [];
+  await PlacesUtils.bookmarks.fetch({ url }, b => bookmarks.push(b), {
+    includeItemIds: true,
+  });
+
+  const notifications = bookmarks.map(
+    bookmark =>
+      new PlacesBookmarkKeyword({
+        id: bookmark.itemId,
+        itemType: bookmark.type,
+        url,
+        guid: bookmark.guid,
+        parentGuid: bookmark.parentGuid,
+        keyword,
+        lastModified: bookmark.lastModified,
+        source,
+        isTagging: false,
+      })
+  );
+  if (notifications.length) {
+    PlacesObservers.notifyListeners(notifications);
+  }
+}
+
+/**
+ * Serializes the given node in JSON format.
+ *
+ * @param aNode
+ *        An nsINavHistoryResultNode
+ */
+function serializeNode(aNode) {
+  let data = {};
+
+  data.title = aNode.title;
+  // The id is no longer used for copying within the same instance/session of
+  // Firefox as of at least 61. However, we keep the id for now to maintain
+  // backwards compat of drag and drop with older Firefox versions.
+  data.id = aNode.itemId;
+  data.itemGuid = aNode.bookmarkGuid;
+  // Add an instanceId so we can tell which instance of an FF session the data
+  // is coming from.
+  data.instanceId = PlacesUtils.instanceId;
+
+  let guid = aNode.bookmarkGuid;
+
+  // Some nodes, e.g. the unfiled/menu/toolbar ones can have a virtual guid, so
+  // we ignore any that are a folder shortcut. These will be handled below.
+  if (
+    guid &&
+    !PlacesUtils.bookmarks.isVirtualRootItem(guid) &&
+    !PlacesUtils.isVirtualLeftPaneItem(guid)
+  ) {
+    if (aNode.parent) {
+      data.parent = aNode.parent.itemId;
+      data.parentGuid = aNode.parent.bookmarkGuid;
+    }
+
+    data.dateAdded = aNode.dateAdded;
+    data.lastModified = aNode.lastModified;
+  }
+
+  if (PlacesUtils.nodeIsURI(aNode)) {
+    // Check for url validity.
+    new URL(aNode.uri);
+    data.type = PlacesUtils.TYPE_X_MOZ_PLACE;
+    data.uri = aNode.uri;
+    if (aNode.tags) {
+      data.tags = aNode.tags;
+    }
+  } else if (PlacesUtils.nodeIsFolder(aNode)) {
+    if (aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT) {
+      data.type = PlacesUtils.TYPE_X_MOZ_PLACE;
+      data.uri = aNode.uri;
+      data.concreteGuid = PlacesUtils.getConcreteItemGuid(aNode);
+    } else {
+      data.type = PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER;
+    }
+  } else if (PlacesUtils.nodeIsQuery(aNode)) {
+    data.type = PlacesUtils.TYPE_X_MOZ_PLACE;
+    data.uri = aNode.uri;
+  } else if (PlacesUtils.nodeIsSeparator(aNode)) {
+    data.type = PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR;
+  }
+
+  return JSON.stringify(data);
+}
+
+// Imposed to limit database size.
+const DB_URL_LENGTH_MAX = 65536;
+const DB_TITLE_LENGTH_MAX = 4096;
+const DB_DESCRIPTION_LENGTH_MAX = 256;
+const DB_SITENAME_LENGTH_MAX = 50;
+
+/**
+ * Executes a boolean validate function, throwing if it returns false.
+ *
+ * @param boolValidateFn
+ *        A boolean validate function.
+ * @return the input value.
+ * @throws if input doesn't pass the validate function.
+ */
+function simpleValidateFunc(boolValidateFn) {
+  return (v, input) => {
+    if (!boolValidateFn(v, input)) {
+      throw new Error("Invalid value");
+    }
+    return v;
+  };
+}
+
+/**
+ * List of bookmark object validators, one per each known property.
+ * Validators must throw if the property value is invalid and return a fixed up
+ * version of the value, if needed.
+ */
+const BOOKMARK_VALIDATORS = Object.freeze({
+  guid: simpleValidateFunc(v => PlacesUtils.isValidGuid(v)),
+  parentGuid: simpleValidateFunc(v => PlacesUtils.isValidGuid(v)),
+  guidPrefix: simpleValidateFunc(v => PlacesUtils.isValidGuidPrefix(v)),
+  index: simpleValidateFunc(
+    v => Number.isInteger(v) && v >= PlacesUtils.bookmarks.DEFAULT_INDEX
+  ),
+  dateAdded: simpleValidateFunc(v => v.constructor.name == "Date" && !isNaN(v)),
+  lastModified: simpleValidateFunc(
+    v => v.constructor.name == "Date" && !isNaN(v)
+  ),
+  type: simpleValidateFunc(
+    v =>
+      Number.isInteger(v) &&
+      [
+        PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        PlacesUtils.bookmarks.TYPE_FOLDER,
+        PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      ].includes(v)
+  ),
+  title: v => {
+    if (v === null) {
+      return "";
+    }
+    if (typeof v == "string") {
+      return v.slice(0, DB_TITLE_LENGTH_MAX);
+    }
+    throw new Error("Invalid title");
+  },
+  url: v => {
+    simpleValidateFunc(
+      val =>
+        (typeof val == "string" && val.length <= DB_URL_LENGTH_MAX) ||
+        (val instanceof Ci.nsIURI && val.spec.length <= DB_URL_LENGTH_MAX) ||
+        (URL.isInstance(val) && val.href.length <= DB_URL_LENGTH_MAX)
+    )(v);
+    if (typeof v === "string") {
+      return new URL(v);
+    }
+    if (v instanceof Ci.nsIURI) {
+      return URL.fromURI(v);
+    }
+    return v;
+  },
+  source: simpleValidateFunc(
+    v =>
+      Number.isInteger(v) &&
+      Object.values(PlacesUtils.bookmarks.SOURCES).includes(v)
+  ),
+  keyword: simpleValidateFunc(v => typeof v == "string" && v.length),
+  charset: simpleValidateFunc(v => typeof v == "string" && v.length),
+  postData: simpleValidateFunc(v => typeof v == "string" && v.length),
+  tags: simpleValidateFunc(
+    v =>
+      Array.isArray(v) &&
+      v.length &&
+      v.every(item => item && typeof item == "string")
+  ),
+});
+
+// Sync bookmark records can contain additional properties.
+const SYNC_BOOKMARK_VALIDATORS = Object.freeze({
+  // Sync uses Places GUIDs for all records except roots.
+  recordId: simpleValidateFunc(
+    v =>
+      typeof v == "string" &&
+      (lazy.PlacesSyncUtils.bookmarks.ROOTS.includes(v) ||
+        PlacesUtils.isValidGuid(v))
+  ),
+  parentRecordId: v => SYNC_BOOKMARK_VALIDATORS.recordId(v),
+  // Sync uses kinds instead of types.
+  kind: simpleValidateFunc(
+    v =>
+      typeof v == "string" &&
+      Object.values(lazy.PlacesSyncUtils.bookmarks.KINDS).includes(v)
+  ),
+  query: simpleValidateFunc(v => v === null || (typeof v == "string" && v)),
+  folder: simpleValidateFunc(
+    v =>
+      typeof v == "string" &&
+      v &&
+      v.length <= PlacesUtils.bookmarks.MAX_TAG_LENGTH
+  ),
+  tags: v => {
+    if (v === null) {
+      return [];
+    }
+    if (!Array.isArray(v)) {
+      throw new Error("Invalid tag array");
+    }
+    for (let tag of v) {
+      if (
+        typeof tag != "string" ||
+        !tag ||
+        tag.length > PlacesUtils.bookmarks.MAX_TAG_LENGTH
+      ) {
+        throw new Error(`Invalid tag: ${tag}`);
+      }
+    }
+    return v;
+  },
+  keyword: simpleValidateFunc(v => v === null || typeof v == "string"),
+  dateAdded: simpleValidateFunc(
+    v =>
+      typeof v === "number" &&
+      v > lazy.PlacesSyncUtils.bookmarks.EARLIEST_BOOKMARK_TIMESTAMP
+  ),
+  feed: v => (v === null ? v : BOOKMARK_VALIDATORS.url(v)),
+  site: v => (v === null ? v : BOOKMARK_VALIDATORS.url(v)),
+  title: BOOKMARK_VALIDATORS.title,
+  url: BOOKMARK_VALIDATORS.url,
+});
+
+// Sync change records are passed between `PlacesSyncUtils` and the Sync
+// bookmarks engine, and are used to update an item's sync status and change
+// counter at the end of a sync.
+const SYNC_CHANGE_RECORD_VALIDATORS = Object.freeze({
+  modified: simpleValidateFunc(v => typeof v == "number" && v >= 0),
+  counter: simpleValidateFunc(v => typeof v == "number" && v >= 0),
+  status: simpleValidateFunc(
+    v =>
+      typeof v == "number" &&
+      Object.values(PlacesUtils.bookmarks.SYNC_STATUS).includes(v)
+  ),
+  tombstone: simpleValidateFunc(v => v === true || v === false),
+  synced: simpleValidateFunc(v => v === true || v === false),
+});
+/**
+ * List PageInfo bookmark object validators.
+ */
+const PAGEINFO_VALIDATORS = Object.freeze({
+  guid: BOOKMARK_VALIDATORS.guid,
+  url: BOOKMARK_VALIDATORS.url,
+  title: v => {
+    if (v == null || v == undefined) {
+      return undefined;
+    } else if (typeof v === "string") {
+      return v;
+    }
+    throw new TypeError(
+      `title property of PageInfo object: ${v} must be a string if provided`
+    );
+  },
+  previewImageURL: v => {
+    if (!v) {
+      return null;
+    }
+    return BOOKMARK_VALIDATORS.url(v);
+  },
+  description: v => {
+    if (typeof v === "string" || v === null) {
+      return v ? v.slice(0, DB_DESCRIPTION_LENGTH_MAX) : null;
+    }
+    throw new TypeError(
+      `description property of pageInfo object: ${v} must be either a string or null if provided`
+    );
+  },
+  siteName: v => {
+    if (typeof v === "string" || v === null) {
+      return v ? v.slice(0, DB_SITENAME_LENGTH_MAX) : null;
+    }
+    throw new TypeError(
+      `siteName property of pageInfo object: ${v} must be either a string or null if provided`
+    );
+  },
+  annotations: v => {
+    if (typeof v != "object" || v.constructor.name != "Map") {
+      throw new TypeError("annotations must be a Map");
+    }
+
+    if (v.size == 0) {
+      throw new TypeError("there must be at least one annotation");
+    }
+
+    for (let [key, value] of v.entries()) {
+      if (typeof key != "string") {
+        throw new TypeError("all annotation keys must be strings");
+      }
+      if (
+        typeof value != "string" &&
+        typeof value != "number" &&
+        typeof value != "boolean" &&
+        value !== null &&
+        value !== undefined
+      ) {
+        throw new TypeError(
+          "all annotation values must be Boolean, Numbers or Strings"
+        );
+      }
+    }
+    return v;
+  },
+  visits: v => {
+    if (!Array.isArray(v) || !v.length) {
+      throw new TypeError("PageInfo object must have an array of visits");
+    }
+    let visits = [];
+    for (let inVisit of v) {
+      let visit = {
+        date: new Date(),
+        transition: inVisit.transition || lazy.History.TRANSITIONS.LINK,
+      };
+
+      if (!PlacesUtils.history.isValidTransition(visit.transition)) {
+        throw new TypeError(
+          `transition: ${visit.transition} is not a valid transition type`
+        );
+      }
+
+      if (inVisit.date) {
+        PlacesUtils.history.ensureDate(inVisit.date);
+        if (inVisit.date > Date.now() + TIMERS_RESOLUTION_SKEW_MS) {
+          throw new TypeError(`date: ${inVisit.date} cannot be a future date`);
+        }
+        visit.date = inVisit.date;
+      }
+
+      if (inVisit.referrer) {
+        visit.referrer = PlacesUtils.normalizeToURLOrGUID(inVisit.referrer);
+      }
+      visits.push(visit);
+    }
+    return visits;
+  },
+});
+
+export var PlacesUtils = {
+  // Place entries that are containers, e.g. bookmark folders or queries.
+  TYPE_X_MOZ_PLACE_CONTAINER: "text/x-moz-place-container",
+  // Place entries that are bookmark separators.
+  TYPE_X_MOZ_PLACE_SEPARATOR: "text/x-moz-place-separator",
+  // Place entries that are not containers or separators
+  TYPE_X_MOZ_PLACE: "text/x-moz-place",
+  // Place entries in shortcut url format (url\ntitle)
+  TYPE_X_MOZ_URL: "text/x-moz-url",
+  // Place entries formatted as HTML anchors
+  TYPE_HTML: "text/html",
+  // Place entries as raw URL text
+  TYPE_PLAINTEXT: "text/plain",
+  // Used to track the action that populated the clipboard.
+  TYPE_X_MOZ_PLACE_ACTION: "text/x-moz-place-action",
+
+  // Deprecated: Remaining only for supporting migration of old livemarks.
+  LMANNO_FEEDURI: "livemark/feedURI",
+  LMANNO_SITEURI: "livemark/siteURI",
+  CHARSET_ANNO: "URIProperties/characterSet",
+  // Deprecated: This is only used for supporting import from older datasets.
+  MOBILE_ROOT_ANNO: "mobile/bookmarksRoot",
+
+  TOPIC_SHUTDOWN: "places-shutdown",
+  TOPIC_INIT_COMPLETE: "places-init-complete",
+  TOPIC_DATABASE_LOCKED: "places-database-locked",
+  TOPIC_EXPIRATION_FINISHED: "places-expiration-finished",
+  TOPIC_FAVICONS_EXPIRED: "places-favicons-expired",
+  TOPIC_VACUUM_STARTING: "places-vacuum-starting",
+  TOPIC_BOOKMARKS_RESTORE_BEGIN: "bookmarks-restore-begin",
+  TOPIC_BOOKMARKS_RESTORE_SUCCESS: "bookmarks-restore-success",
+  TOPIC_BOOKMARKS_RESTORE_FAILED: "bookmarks-restore-failed",
+
+  observers: PlacesObservers,
+
+  /**
+   * GUIDs associated with virtual queries that are used for displaying the
+   * top-level folders in the left pane.
+   */
+  virtualAllBookmarksGuid: "allbms_____v",
+  virtualHistoryGuid: "history____v",
+  virtualDownloadsGuid: "downloads__v",
+  virtualTagsGuid: "tags_______v",
+
+  /**
+   * Checks if a guid is a virtual left-pane root.
+   *
+   * @param {String} guid The guid of the item to look for.
+   * @returns {Boolean} true if guid is a virtual root, false otherwise.
+   */
+  isVirtualLeftPaneItem(guid) {
+    return (
+      guid == PlacesUtils.virtualAllBookmarksGuid ||
+      guid == PlacesUtils.virtualHistoryGuid ||
+      guid == PlacesUtils.virtualDownloadsGuid ||
+      guid == PlacesUtils.virtualTagsGuid
+    );
+  },
+
+  asContainer: aNode => asContainer(aNode),
+  asQuery: aNode => asQuery(aNode),
+
+  endl: NEWLINE,
+
+  /**
+   * Is a string a valid GUID?
+   *
+   * @param guid: (String)
+   * @return (Boolean)
+   */
+  isValidGuid(guid) {
+    return typeof guid == "string" && guid && /^[a-zA-Z0-9\-_]{12}$/.test(guid);
+  },
+
+  /**
+   * Is a string a valid GUID prefix?
+   *
+   * @param guidPrefix: (String)
+   * @return (Boolean)
+   */
+  isValidGuidPrefix(guidPrefix) {
+    return (
+      typeof guidPrefix == "string" &&
+      guidPrefix &&
+      /^[a-zA-Z0-9\-_]{1,11}$/.test(guidPrefix)
+    );
+  },
+
+  /**
+   * Generates a random GUID and replace its beginning with the given
+   * prefix. We do this instead of just prepending the prefix to keep
+   * the correct character length.
+   *
+   * @param prefix: (String)
+   * @return (String)
+   */
+  generateGuidWithPrefix(prefix) {
+    return prefix + this.history.makeGuid().substring(prefix.length);
+  },
+
+  /**
+   * Converts a string or n URL object to an nsIURI.
+   *
+   * @param url (URL) or (String)
+   *        the URL to convert.
+   * @return nsIURI for the given URL.
+   */
+  toURI(url) {
+    if (url instanceof Ci.nsIURI) {
+      return url;
+    }
+    if (URL.isInstance(url)) {
+      return url.URI;
+    }
+    return Services.io.newURI(url);
+  },
+
+  /**
+   * Convert a Date object to a PRTime (microseconds).
+   *
+   * @param date
+   *        the Date object to convert.
+   * @return microseconds from the epoch.
+   */
+  toPRTime(date) {
+    if (
+      (typeof date != "number" && date.constructor.name != "Date") ||
+      isNaN(date)
+    ) {
+      throw new Error("Invalid value passed to toPRTime");
+    }
+    return date * 1000;
+  },
+
+  /**
+   * Convert a PRTime to a Date object.
+   *
+   * @param time
+   *        microseconds from the epoch.
+   * @return a Date object.
+   */
+  toDate(time) {
+    if (typeof time != "number" || isNaN(time)) {
+      throw new Error("Invalid value passed to toDate");
+    }
+    return new Date(parseInt(time / 1000));
+  },
+
+  /**
+   * Wraps a string in a nsISupportsString wrapper.
+   * @param   aString
+   *          The string to wrap.
+   * @returns A nsISupportsString object containing a string.
+   */
+  toISupportsString: function PU_toISupportsString(aString) {
+    let s = Cc["@mozilla.org/supports-string;1"].createInstance(
+      Ci.nsISupportsString
+    );
+    s.data = aString;
+    return s;
+  },
+
+  getFormattedString: function PU_getFormattedString(key, params) {
+    return lazy.bundle.formatStringFromName(key, params);
+  },
+
+  getString: function PU_getString(key) {
+    return lazy.bundle.GetStringFromName(key);
+  },
+
+  /**
+   * Parses a moz-action URL and returns its parts.
+   *
+   * @param url A moz-action URI.
+   * @note URL is in the format moz-action:ACTION,JSON_ENCODED_PARAMS
+   */
+  parseActionUrl(url) {
+    if (url instanceof Ci.nsIURI) {
+      url = url.spec;
+    } else if (URL.isInstance(url)) {
+      url = url.href;
+    }
+    // Faster bailout.
+    if (!url.startsWith("moz-action:")) {
+      return null;
+    }
+
+    try {
+      let [, type, params] = url.match(lazy.MOZ_ACTION_REGEX);
+      let action = {
+        type,
+        params: JSON.parse(params),
+      };
+      for (let key in action.params) {
+        action.params[key] = decodeURIComponent(action.params[key]);
+      }
+      return action;
+    } catch (ex) {
+      console.error(`Invalid action url "${url}"`);
+      return null;
+    }
+  },
+
+  /**
+   * Determines if a folder is generated from a query.
+   * @param aNode a result true.
+   * @returns true if the node is a folder generated from a query.
+   */
+  isQueryGeneratedFolder(node) {
+    if (!node.parent) {
+      return false;
+    }
+    return this.nodeIsFolder(node) && this.nodeIsQuery(node.parent);
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a Bookmark folder.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a Bookmark folder, false otherwise
+   */
+  nodeIsFolder: function PU_nodeIsFolder(aNode) {
+    return (
+      aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER ||
+      aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT
+    );
+  },
+
+  /**
+   * Determines whether or not a ResultNode represents a bookmarked URI.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node represents a bookmarked URI, false otherwise
+   */
+  nodeIsBookmark: function PU_nodeIsBookmark(aNode) {
+    return (
+      aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_URI &&
+      (aNode.itemId != -1 || aNode.bookmarkGuid)
+    );
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a Bookmark separator.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a Bookmark separator, false otherwise
+   */
+  nodeIsSeparator: function PU_nodeIsSeparator(aNode) {
+    return aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR;
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a URL item.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a URL item, false otherwise
+   */
+  nodeIsURI: function PU_nodeIsURI(aNode) {
+    return aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_URI;
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a Query item.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a Query item, false otherwise
+   */
+  nodeIsQuery: function PU_nodeIsQuery(aNode) {
+    return aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY;
+  },
+
+  /**
+   * Generator for a node's ancestors.
+   * @param aNode
+   *        A result node
+   */
+  nodeAncestors: function* PU_nodeAncestors(aNode) {
+    let node = aNode.parent;
+    while (node) {
+      yield node;
+      node = node.parent;
+    }
+  },
+
+  /**
+   * Checks validity of an object, filling up default values for optional
+   * properties.
+   *
+   * @param {string} name
+   *        The operation name. This is included in the error message if
+   *        validation fails.
+   * @param validators (object)
+   *        An object containing input validators. Keys should be field names;
+   *        values should be validation functions.
+   * @param props (object)
+   *        The object to validate.
+   * @param behavior (object) [optional]
+   *        Object defining special behavior for some of the properties.
+   *        The following behaviors may be optionally set:
+   *         - required: this property is required.
+   *         - replaceWith: this property will be overwritten with the value
+   *                        provided
+   *         - requiredIf: if the provided condition is satisfied, then this
+   *                       property is required.
+   *         - validIf: if the provided condition is not satisfied, then this
+   *                    property is invalid.
+   *         - defaultValue: an undefined property should default to this value.
+   *         - fixup: a function invoked when validation fails, takes the input
+   *                  object as argument and must fix the property.
+   *
+   * @return a validated and normalized item.
+   * @throws if the object contains invalid data.
+   * @note any unknown properties are pass-through.
+   */
+  validateItemProperties(name, validators, props, behavior = {}) {
+    if (typeof props != "object" || !props) {
+      throw new Error(`${name}: Input should be a valid object`);
+    }
+    // Make a shallow copy of `props` to avoid mutating the original object
+    // when filling in defaults.
+    let input = Object.assign({}, props);
+    let normalizedInput = {};
+    let required = new Set();
+    for (let prop in behavior) {
+      if (
+        behavior[prop].hasOwnProperty("required") &&
+        behavior[prop].required
+      ) {
+        required.add(prop);
+      }
+      if (
+        behavior[prop].hasOwnProperty("requiredIf") &&
+        behavior[prop].requiredIf(input)
+      ) {
+        required.add(prop);
+      }
+      if (
+        behavior[prop].hasOwnProperty("validIf") &&
+        input[prop] !== undefined &&
+        !behavior[prop].validIf(input)
+      ) {
+        if (behavior[prop].hasOwnProperty("fixup")) {
+          behavior[prop].fixup(input);
+        } else {
+          throw new Error(
+            `${name}: Invalid value for property '${prop}': ${JSON.stringify(
+              input[prop]
+            )}`
+          );
+        }
+      }
+      if (
+        behavior[prop].hasOwnProperty("defaultValue") &&
+        input[prop] === undefined
+      ) {
+        input[prop] = behavior[prop].defaultValue;
+      }
+      if (behavior[prop].hasOwnProperty("replaceWith")) {
+        input[prop] = behavior[prop].replaceWith;
+      }
+    }
+
+    for (let prop in input) {
+      if (required.has(prop)) {
+        required.delete(prop);
+      } else if (input[prop] === undefined) {
+        // Skip undefined properties that are not required.
+        continue;
+      }
+      if (validators.hasOwnProperty(prop)) {
+        try {
+          normalizedInput[prop] = validators[prop](input[prop], input);
+        } catch (ex) {
+          if (
+            behavior.hasOwnProperty(prop) &&
+            behavior[prop].hasOwnProperty("fixup")
+          ) {
+            behavior[prop].fixup(input);
+            normalizedInput[prop] = input[prop];
+          } else {
+            throw new Error(
+              `${name}: Invalid value for property '${prop}': ${JSON.stringify(
+                input[prop]
+              )}`
+            );
+          }
+        }
+      }
+    }
+    if (required.size > 0) {
+      throw new Error(
+        `${name}: The following properties were expected: ${[...required].join(
+          ", "
+        )}`
+      );
+    }
+    return normalizedInput;
+  },
+
+  BOOKMARK_VALIDATORS,
+  PAGEINFO_VALIDATORS,
+  SYNC_BOOKMARK_VALIDATORS,
+  SYNC_CHANGE_RECORD_VALIDATORS,
+
+  QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+
+  _shutdownFunctions: [],
+  registerShutdownFunction: function PU_registerShutdownFunction(aFunc) {
+    // If this is the first registered function, add the shutdown observer.
+    if (!this._shutdownFunctions.length) {
+      Services.obs.addObserver(this, this.TOPIC_SHUTDOWN);
+    }
+    this._shutdownFunctions.push(aFunc);
+  },
+
+  // nsIObserver
+  observe: function PU_observe(aSubject, aTopic, aData) {
+    switch (aTopic) {
+      case this.TOPIC_SHUTDOWN:
+        Services.obs.removeObserver(this, this.TOPIC_SHUTDOWN);
+        while (this._shutdownFunctions.length) {
+          this._shutdownFunctions.shift().apply(this);
+        }
+        break;
+    }
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a host container.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a host container, false otherwise
+   */
+  nodeIsHost: function PU_nodeIsHost(aNode) {
+    return (
+      aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY &&
+      aNode.parent &&
+      asQuery(aNode.parent).queryOptions.resultType ==
+        Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY
+    );
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a day container.
+   * @param   node
+   *          A NavHistoryResultNode
+   * @returns true if the node is a day container, false otherwise
+   */
+  nodeIsDay: function PU_nodeIsDay(aNode) {
+    var resultType;
+    return (
+      aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY &&
+      aNode.parent &&
+      ((resultType = asQuery(aNode.parent).queryOptions.resultType) ==
+        Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+        resultType == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY)
+    );
+  },
+
+  /**
+   * Determines whether or not a result-node is a tag container.
+   * @param   aNode
+   *          A result-node
+   * @returns true if the node is a tag container, false otherwise
+   */
+  nodeIsTagQuery: function PU_nodeIsTagQuery(aNode) {
+    if (aNode.type != Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY) {
+      return false;
+    }
+    // Direct child of RESULTS_AS_TAGS_ROOT.
+    let parent = aNode.parent;
+    if (
+      parent &&
+      PlacesUtils.asQuery(parent).queryOptions.resultType ==
+        Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAGS_ROOT
+    ) {
+      return true;
+    }
+    // We must also support the right pane of the Library, when the tag query
+    // is the root node. Unfortunately this is also valid for any tag query
+    // selected in the left pane that is not a direct child of RESULTS_AS_TAGS_ROOT.
+    if (
+      !parent &&
+      aNode == aNode.parentResult.root &&
+      PlacesUtils.asQuery(aNode).query.tags.length == 1
+    ) {
+      return true;
+    }
+    return false;
+  },
+
+  /**
+   * Determines whether or not a ResultNode is a container.
+   * @param   aNode
+   *          A result node
+   * @returns true if the node is a container item, false otherwise
+   */
+  containerTypes: [
+    Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER,
+    Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT,
+    Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY,
+  ],
+  nodeIsContainer: function PU_nodeIsContainer(aNode) {
+    return this.containerTypes.includes(aNode.type);
+  },
+
+  /**
+   * Determines whether or not a ResultNode is an history related container.
+   * @param   node
+   *          A result node
+   * @returns true if the node is an history related container, false otherwise
+   */
+  nodeIsHistoryContainer: function PU_nodeIsHistoryContainer(aNode) {
+    var resultType;
+    return (
+      this.nodeIsQuery(aNode) &&
+      ((resultType = asQuery(aNode).queryOptions.resultType) ==
+        Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY ||
+        resultType == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+        resultType == Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY ||
+        this.nodeIsDay(aNode) ||
+        this.nodeIsHost(aNode))
+    );
+  },
+
+  /**
+   * Gets the concrete item-guid for the given node. For everything but folder
+   * shortcuts, this is just node.bookmarkGuid.  For folder shortcuts, this is
+   * node.targetFolderGuid (see nsINavHistoryService.idl for the semantics).
+   *
+   * @param aNode
+   *        a result node.
+   * @return the concrete item-guid for aNode.
+   */
+  getConcreteItemGuid(aNode) {
+    if (aNode.type == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT) {
+      return asQuery(aNode).targetFolderGuid;
+    }
+    return aNode.bookmarkGuid;
+  },
+
+  /**
+   * Reverse a host based on the moz_places algorithm, that is reverse the host
+   * string and add a trailing period.  For example "google.com" becomes
+   * "moc.elgoog.".
+   *
+   * @param url
+   *        the URL to generate a rev host for.
+   * @return the reversed host string.
+   */
+  getReversedHost(url) {
+    return url.host.split("").reverse().join("") + ".";
+  },
+
+  /**
+   * String-wraps a result node according to the rules of the specified
+   * content type for copy or move operations.
+   *
+   * @param   aNode
+   *          The Result node to wrap (serialize)
+   * @param   aType
+   *          The content type to serialize as
+   * @return  A string serialization of the node
+   */
+  wrapNode(aNode, aType) {
+    // when wrapping a node, we want all the items, even if the original
+    // query options are excluding them.
+    // This can happen when copying from the left hand pane of the bookmarks
+    // organizer.
+    // @return [node, shouldClose]
+    function gatherDataFromNode(node, gatherDataFunc) {
+      if (
+        PlacesUtils.nodeIsFolder(node) &&
+        node.type != Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT &&
+        asQuery(node).queryOptions.excludeItems
+      ) {
+        let folderRoot = PlacesUtils.getFolderContents(
+          node.bookmarkGuid,
+          false,
+          true
+        ).root;
+        try {
+          return gatherDataFunc(folderRoot);
+        } finally {
+          folderRoot.containerOpen = false;
+        }
+      }
+      // If we didn't create our own query, do not alter the node's state.
+      return gatherDataFunc(node);
+    }
+
+    function gatherDataHtml(node) {
+      let htmlEscape = s =>
+        s
+          .replace(/&/g, "&amp;")
+          .replace(/>/g, "&gt;")
+          .replace(/</g, "&lt;")
+          .replace(/"/g, "&quot;")
+          .replace(/'/g, "&apos;");
+
+      // escape out potential HTML in the title
+      let escapedTitle = node.title ? htmlEscape(node.title) : "";
+
+      if (PlacesUtils.nodeIsContainer(node)) {
+        asContainer(node);
+        let wasOpen = node.containerOpen;
+        if (!wasOpen) {
+          node.containerOpen = true;
+        }
+
+        let childString = "<DL><DT>" + escapedTitle + "</DT>" + NEWLINE;
+        let cc = node.childCount;
+        for (let i = 0; i < cc; ++i) {
+          childString +=
+            "<DD>" +
+            NEWLINE +
+            gatherDataHtml(node.getChild(i)) +
+            "</DD>" +
+            NEWLINE;
+        }
+        node.containerOpen = wasOpen;
+        return childString + "</DL>" + NEWLINE;
+      }
+      if (PlacesUtils.nodeIsURI(node)) {
+        return `<A HREF="${node.uri}">${escapedTitle}</A>${NEWLINE}`;
+      }
+      if (PlacesUtils.nodeIsSeparator(node)) {
+        return "<HR>" + NEWLINE;
+      }
+      return "";
+    }
+
+    function gatherDataText(node) {
+      if (PlacesUtils.nodeIsContainer(node)) {
+        asContainer(node);
+        let wasOpen = node.containerOpen;
+        if (!wasOpen) {
+          node.containerOpen = true;
+        }
+
+        let childString = node.title + NEWLINE;
+        let cc = node.childCount;
+        for (let i = 0; i < cc; ++i) {
+          let child = node.getChild(i);
+          let suffix = i < cc - 1 ? NEWLINE : "";
+          childString += gatherDataText(child) + suffix;
+        }
+        node.containerOpen = wasOpen;
+        return childString;
+      }
+      if (PlacesUtils.nodeIsURI(node)) {
+        return node.uri;
+      }
+      if (PlacesUtils.nodeIsSeparator(node)) {
+        return "--------------------";
+      }
+      return "";
+    }
+
+    switch (aType) {
+      case this.TYPE_X_MOZ_PLACE:
+      case this.TYPE_X_MOZ_PLACE_SEPARATOR:
+      case this.TYPE_X_MOZ_PLACE_CONTAINER: {
+        // Serialize the node to JSON.
+        return serializeNode(aNode);
+      }
+      case this.TYPE_X_MOZ_URL: {
+        if (PlacesUtils.nodeIsURI(aNode)) {
+          return aNode.uri + NEWLINE + aNode.title;
+        }
+        if (PlacesUtils.nodeIsContainer(aNode)) {
+          return PlacesUtils.getURLsForContainerNode(aNode)
+            .map(item => item.uri + "\n" + item.title)
+            .join("\n");
+        }
+        return "";
+      }
+      case this.TYPE_HTML: {
+        return gatherDataFromNode(aNode, gatherDataHtml);
+      }
+    }
+
+    // Otherwise, we wrap as TYPE_PLAINTEXT.
+    return gatherDataFromNode(aNode, gatherDataText);
+  },
+
+  /**
+   * Unwraps data from the Clipboard or the current Drag Session.
+   * @param   blob
+   *          A blob (string) of data, in some format we potentially know how
+   *          to parse.
+   * @param   type
+   *          The content type of the blob.
+   * @returns An array of objects representing each item contained by the source.
+   * @throws if the blob contains invalid data.
+   */
+  unwrapNodes: function PU_unwrapNodes(blob, type) {
+    // We split on "\n"  because the transferable system converts "\r\n" to "\n"
+    var nodes = [];
+    switch (type) {
+      case this.TYPE_X_MOZ_PLACE:
+      case this.TYPE_X_MOZ_PLACE_SEPARATOR:
+      case this.TYPE_X_MOZ_PLACE_CONTAINER:
+        nodes = JSON.parse("[" + blob + "]");
+        break;
+      case this.TYPE_X_MOZ_URL: {
+        let parts = blob.split("\n");
+        // data in this type has 2 parts per entry, so if there are fewer
+        // than 2 parts left, the blob is malformed and we should stop
+        // but drag and drop of files from the shell has parts.length = 1
+        if (parts.length != 1 && parts.length % 2) {
+          break;
+        }
+        for (let i = 0; i < parts.length; i = i + 2) {
+          let uriString = parts[i];
+          let titleString = "";
+          if (parts.length > i + 1) {
+            titleString = parts[i + 1];
+          } else {
+            // for drag and drop of files, try to use the leafName as title
+            try {
+              titleString = Services.io
+                .newURI(uriString)
+                .QueryInterface(Ci.nsIURL).fileName;
+            } catch (ex) {}
+          }
+          // note:  Services.io.newURI() will throw if uriString is not a valid URI
+          let uri = Services.io.newURI(uriString);
+          if (Services.io.newURI(uriString) && uri.scheme != "place") {
+            nodes.push({
+              uri: uriString,
+              title: titleString ? titleString : uriString,
+              type: this.TYPE_X_MOZ_URL,
+            });
+          }
+        }
+        break;
+      }
+      case this.TYPE_PLAINTEXT: {
+        let parts = blob.split("\n");
+        for (let i = 0; i < parts.length; i++) {
+          let uriString = parts[i];
+          // text/uri-list is converted to TYPE_PLAINTEXT but it could contain
+          // comments line prepended by #, we should skip them, as well as
+          // empty uris.
+          if (uriString.substr(0, 1) == "\x23" || uriString == "") {
+            continue;
+          }
+          // note: Services.io.newURI) will throw if uriString is not a valid URI
+          let uri = Services.io.newURI(uriString);
+          if (uri.scheme != "place") {
+            nodes.push({
+              uri: uriString,
+              title: uriString,
+              type: this.TYPE_X_MOZ_URL,
+            });
+          }
+        }
+        break;
+      }
+      default:
+        throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+    return nodes;
+  },
+
+  /**
+   * Validate an input PageInfo object, returning a valid PageInfo object.
+   *
+   * @param pageInfo: (PageInfo)
+   * @return (PageInfo)
+   */
+  validatePageInfo(pageInfo, validateVisits = true) {
+    return this.validateItemProperties(
+      "PageInfo",
+      PAGEINFO_VALIDATORS,
+      pageInfo,
+      {
+        url: { requiredIf: b => !b.guid },
+        guid: { requiredIf: b => !b.url },
+        visits: { requiredIf: b => validateVisits },
+      }
+    );
+  },
+  /**
+   * Normalize a key to either a string (if it is a valid GUID) or an
+   * instance of `URL` (if it is a `URL`, `nsIURI`, or a string
+   * representing a valid url).
+   *
+   * @throws (TypeError)
+   *         If the key is neither a valid guid nor a valid url.
+   */
+  normalizeToURLOrGUID(key) {
+    if (typeof key === "string") {
+      // A string may be a URL or a guid
+      if (this.isValidGuid(key)) {
+        return key;
+      }
+      return new URL(key);
+    }
+    if (URL.isInstance(key)) {
+      return key;
+    }
+    if (key instanceof Ci.nsIURI) {
+      return URL.fromURI(key);
+    }
+    throw new TypeError("Invalid url or guid: " + key);
+  },
+
+  /**
+   * Generates a nsINavHistoryResult for the contents of a folder.
+   * @param   aFolderGuid
+   *          The folder to open
+   * @param   [optional] excludeItems
+   *          True to hide all items (individual bookmarks). This is used on
+   *          the left places pane so you just get a folder hierarchy.
+   * @param   [optional] expandQueries
+   *          True to make query items expand as new containers. For managing,
+   *          you want this to be false, for menus and such, you want this to
+   *          be true.
+   * @returns A nsINavHistoryResult containing the contents of the
+   *          folder. The result.root is guaranteed to be open.
+   */
+  getFolderContents(aFolderGuid, aExcludeItems, aExpandQueries) {
+    if (!this.isValidGuid(aFolderGuid)) {
+      throw new Error("aFolderGuid should be a valid GUID.");
+    }
+    var query = this.history.getNewQuery();
+    query.setParents([aFolderGuid]);
+    var options = this.history.getNewQueryOptions();
+    options.excludeItems = aExcludeItems;
+    options.expandQueries = aExpandQueries;
+
+    var result = this.history.executeQuery(query, options);
+    result.root.containerOpen = true;
+    return result;
+  },
+
+  // Identifier getters for special folders.
+  // You should use these everywhere PlacesUtils is available to avoid XPCOM
+  // traversal just to get roots' ids.
+  get tagsFolderId() {
+    delete this.tagsFolderId;
+    return (this.tagsFolderId = this.bookmarks.tagsFolder);
+  },
+
+  /**
+   * Checks if item is a root.
+   *
+   * @param {String} guid The guid of the item to look for.
+   * @returns {Boolean} true if guid is a root, false otherwise.
+   */
+  isRootItem(guid) {
+    return (
+      guid == PlacesUtils.bookmarks.menuGuid ||
+      guid == PlacesUtils.bookmarks.toolbarGuid ||
+      guid == PlacesUtils.bookmarks.unfiledGuid ||
+      guid == PlacesUtils.bookmarks.tagsGuid ||
+      guid == PlacesUtils.bookmarks.rootGuid ||
+      guid == PlacesUtils.bookmarks.mobileGuid
+    );
+  },
+
+  /**
+   * Returns a nsNavHistoryContainerResultNode with forced excludeItems and
+   * expandQueries.
+   * @param   aNode
+   *          The node to convert
+   * @param   [optional] excludeItems
+   *          True to hide all items (individual bookmarks). This is used on
+   *          the left places pane so you just get a folder hierarchy.
+   * @param   [optional] expandQueries
+   *          True to make query items expand as new containers. For managing,
+   *          you want this to be false, for menus and such, you want this to
+   *          be true.
+   * @returns A nsINavHistoryContainerResultNode containing the unfiltered
+   *          contents of the container.
+   * @note    The returned container node could be open or closed, we don't
+   *          guarantee its status.
+   */
+  getContainerNodeWithOptions: function PU_getContainerNodeWithOptions(
+    aNode,
+    aExcludeItems,
+    aExpandQueries
+  ) {
+    if (!this.nodeIsContainer(aNode)) {
+      throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    // excludeItems is inherited by child containers in an excludeItems view.
+    var excludeItems =
+      asQuery(aNode).queryOptions.excludeItems ||
+      asQuery(aNode.parentResult.root).queryOptions.excludeItems;
+    // expandQueries is inherited by child containers in an expandQueries view.
+    var expandQueries =
+      asQuery(aNode).queryOptions.expandQueries &&
+      asQuery(aNode.parentResult.root).queryOptions.expandQueries;
+
+    // If our options are exactly what we expect, directly return the node.
+    if (excludeItems == aExcludeItems && expandQueries == aExpandQueries) {
+      return aNode;
+    }
+
+    // Otherwise, get contents manually.
+    var query = {},
+      options = {};
+    this.history.queryStringToQuery(aNode.uri, query, options);
+    options.value.excludeItems = aExcludeItems;
+    options.value.expandQueries = aExpandQueries;
+    return this.history.executeQuery(query.value, options.value).root;
+  },
+
+  /**
+   * Returns true if a container has uri nodes in its first level.
+   * Has better performance than (getURLsForContainerNode(node).length > 0).
+   * @param aNode
+   *        The container node to search through.
+   * @returns true if the node contains uri nodes, false otherwise.
+   */
+  hasChildURIs: function PU_hasChildURIs(aNode) {
+    if (!this.nodeIsContainer(aNode)) {
+      return false;
+    }
+
+    let root = this.getContainerNodeWithOptions(aNode, false, true);
+    let result = root.parentResult;
+    let didSuppressNotifications = false;
+    let wasOpen = root.containerOpen;
+    if (!wasOpen) {
+      didSuppressNotifications = result.suppressNotifications;
+      if (!didSuppressNotifications) {
+        result.suppressNotifications = true;
+      }
+
+      root.containerOpen = true;
+    }
+
+    let found = false;
+    for (let i = 0; i < root.childCount && !found; i++) {
+      let child = root.getChild(i);
+      if (this.nodeIsURI(child)) {
+        found = true;
+      }
+    }
+
+    if (!wasOpen) {
+      root.containerOpen = false;
+      if (!didSuppressNotifications) {
+        result.suppressNotifications = false;
+      }
+    }
+    return found;
+  },
+
+  /**
+   * Returns an array containing all the uris in the first level of the
+   * passed in container.
+   * If you only need to know if the node contains uris, use hasChildURIs.
+   * @param aNode
+   *        The container node to search through
+   * @returns array of uris in the first level of the container.
+   */
+  getURLsForContainerNode: function PU_getURLsForContainerNode(aNode) {
+    let urls = [];
+    if (!this.nodeIsContainer(aNode)) {
+      return urls;
+    }
+
+    let root = this.getContainerNodeWithOptions(aNode, false, true);
+    let result = root.parentResult;
+    let wasOpen = root.containerOpen;
+    let didSuppressNotifications = false;
+    if (!wasOpen) {
+      didSuppressNotifications = result.suppressNotifications;
+      if (!didSuppressNotifications) {
+        result.suppressNotifications = true;
+      }
+
+      root.containerOpen = true;
+    }
+
+    for (let i = 0; i < root.childCount; ++i) {
+      let child = root.getChild(i);
+      if (this.nodeIsURI(child)) {
+        urls.push({
+          uri: child.uri,
+          isBookmark: this.nodeIsBookmark(child),
+          title: child.title,
+        });
+      }
+    }
+
+    if (!wasOpen) {
+      root.containerOpen = false;
+      if (!didSuppressNotifications) {
+        result.suppressNotifications = false;
+      }
+    }
+    return urls;
+  },
+
+  /**
+   * Gets a shared Sqlite.sys.mjs readonly connection to the Places database,
+   * usable only for SELECT queries.
+   *
+   * This is intended to be used mostly internally, components outside of
+   * Places should, when possible, use API calls and file bugs to get proper
+   * APIs, where they are missing.
+   * Keep in mind the Places DB schema is by no means frozen or even stable.
+   * Your custom queries can - and will - break overtime.
+   *
+   * Example:
+   * let db = await PlacesUtils.promiseDBConnection();
+   * let rows = await db.executeCached(sql, params);
+   */
+  promiseDBConnection: () => lazy.gAsyncDBConnPromised,
+
+  /**
+   * This is pretty much the same as promiseDBConnection, but with a larger
+   * page cache, useful for consumers doing large table scans, like the urlbar.
+   * @see promiseDBConnection
+   */
+  promiseLargeCacheDBConnection: () => lazy.gAsyncDBLargeCacheConnPromised,
+  get largeCacheDBConnDeferred() {
+    return gAsyncDBLargeCacheConnDeferred;
+  },
+
+  /**
+   * Returns a Sqlite.sys.mjs wrapper for the main Places connection. Most callers
+   * should prefer `withConnectionWrapper`, which ensures that all database
+   * operations finish before the connection is closed.
+   */
+  promiseUnsafeWritableDBConnection: () => lazy.gAsyncDBWrapperPromised,
+
+  /**
+   * Performs a read/write operation on the Places database through a Sqlite.sys.mjs
+   * wrapped connection to the Places database.
+   *
+   * This is intended to be used only by Places itself, always use APIs if you
+   * need to modify the Places database. Use promiseDBConnection if you need to
+   * SELECT from the database and there's no covering API.
+   * Keep in mind the Places DB schema is by no means frozen or even stable.
+   * Your custom queries can - and will - break overtime.
+   *
+   * As all operations on the Places database are asynchronous, if shutdown
+   * is initiated while an operation is pending, this could cause dataloss.
+   * Using `withConnectionWrapper` ensures that shutdown waits until all
+   * operations are complete before proceeding.
+   *
+   * Example:
+   * await withConnectionWrapper("Bookmarks: Remove a bookmark", Task.async(function*(db) {
+   *    // Proceed with the db, asynchronously.
+   *    // Shutdown will not interrupt operations that take place here.
+   * }));
+   *
+   * @param {string} name The name of the operation. Used for debugging, logging
+   *   and crash reporting.
+   * @param {function(db)} task A function that takes as argument a Sqlite.sys.mjs
+   *   connection and returns a Promise. Shutdown is guaranteed to not interrupt
+   *   execution of `task`.
+   */
+  async withConnectionWrapper(name, task) {
+    if (!name) {
+      throw new TypeError("Expecting a user-readable name");
+    }
+    let db = await lazy.gAsyncDBWrapperPromised;
+    return db.executeBeforeShutdown(name, task);
+  },
+
+  /**
+   * Gets favicon data for a given page url.
+   *
+   * @param {string | URL | nsIURI} aPageUrl
+   *   url of the page to look favicon for.
+   * @param {number} preferredWidth
+   *   The preferred width of the favicon in pixels. The default value of 0
+   *   returns the largest icon available.
+   * @resolves to an object representing a favicon entry, having the following
+   *           properties: { uri, dataLen, data, mimeType }
+   * @rejects JavaScript exception if the given url has no associated favicon.
+   */
+  promiseFaviconData(aPageUrl, preferredWidth = 0) {
+    return new Promise((resolve, reject) => {
+      if (!(aPageUrl instanceof Ci.nsIURI)) {
+        aPageUrl = PlacesUtils.toURI(aPageUrl);
+      }
+      PlacesUtils.favicons.getFaviconDataForPage(
+        aPageUrl,
+        function (uri, dataLen, data, mimeType, size) {
+          if (uri) {
+            resolve({ uri, dataLen, data, mimeType, size });
+          } else {
+            reject();
+          }
+        },
+        preferredWidth
+      );
+    });
+  },
+
+  /**
+   * Returns the passed URL with a #size ref for the specified size and
+   * devicePixelRatio.
+   *
+   * @param window
+   *        The window where the icon will appear.
+   * @param href
+   *        The string href we should add the ref to.
+   * @param size
+   *        The target image size
+   * @return The URL with the fragment at the end, in the same formar as input.
+   */
+  urlWithSizeRef(window, href, size) {
+    return (
+      href +
+      (href.includes("#") ? "&" : "#") +
+      "size=" +
+      Math.round(size) * window.devicePixelRatio
+    );
+  },
+
+  /**
+   * Asynchronously retrieve a JS-object representation of a places bookmarks
+   * item (a bookmark, a folder, or a separator) along with all of its
+   * descendants.
+   *
+   * @param [optional] aItemGuid
+   *        the (topmost) item to be queried.  If it's not passed, the places
+   *        root is queried: that is, you get a representation of the entire
+   *        bookmarks hierarchy.
+   * @param [optional] aOptions
+   *        Options for customizing the query behavior, in the form of a JS
+   *        object with any of the following properties:
+   *         - excludeItemsCallback: a function for excluding items, along with
+   *           their descendants.  Given an item object (that has everything set
+   *           apart its potential children data), it should return true if the
+   *           item should be excluded.  Once an item is excluded, the function
+   *           isn't called for any of its descendants.  This isn't called for
+   *           the root item.
+   *           WARNING: since the function may be called for each item, using
+   *           this option can slow down the process significantly if the
+   *           callback does anything that's not relatively trivial.  It is
+   *           highly recommended to avoid any synchronous I/O or DB queries.
+   *        - includeItemIds: opt-in to include the deprecated id property.
+   *          Use it if you must. It'll be removed once the switch to GUIDs is
+   *          complete.
+   *
+   * @return {Promise}
+   * @resolves to a JS object that represents either a single item or a
+   * bookmarks tree.  Each node in the tree has the following properties set:
+   *  - guid (string): the item's GUID (same as aItemGuid for the top item).
+   *  - [deprecated] id (number): the item's id. This is only if
+   *    aOptions.includeItemIds is set.
+   *  - type (string):  the item's type.  @see PlacesUtils.TYPE_X_*
+   *  - typeCode (number):  the item's type in numeric format.
+   *    @see PlacesUtils.bookmarks.TYPE_*
+   *  - title (string): the item's title. If it has no title, this property
+   *    isn't set.
+   *  - dateAdded (number, microseconds from the epoch): the date-added value of
+   *    the item.
+   *  - lastModified (number, microseconds from the epoch): the last-modified
+   *    value of the item.
+   *  - index: the item's index under it's parent.
+   *
+   * The root object (i.e. the one for aItemGuid) also has the following
+   * properties set:
+   *  - parentGuid (string): the GUID of the root's parent.  This isn't set if
+   *    the root item is the places root.
+   *  - itemsCount (number, not enumerable): the number of items, including the
+   *    root item itself, which are represented in the resolved object.
+   *
+   * Bookmark items also have the following properties:
+   *  - uri (string): the item's url.
+   *  - tags (string): csv string of the bookmark's tags.
+   *  - charset (string): the last known charset of the bookmark.
+   *  - keyword (string): the bookmark's keyword (unset if none).
+   *  - postData (string): the bookmark's keyword postData (unset if none).
+   *  - iconUri (string): the bookmark's favicon url.
+   * The last four properties are not set at all if they're irrelevant (e.g.
+   * |charset| is not set if no charset was previously set for the bookmark
+   * url).
+   *
+   * Folders may also have the following properties:
+   *  - children (array): the folder's children information, each of them
+   *    having the same set of properties as above.
+   *
+   * @rejects if the query failed for any reason.
+   * @note if aItemGuid points to a non-existent item, the returned promise is
+   * resolved to null.
+   */
+  async promiseBookmarksTree(aItemGuid = "", aOptions = {}) {
+    let createItemInfoObject = async function (aRow, aIncludeParentGuid) {
+      let item = {};
+      let copyProps = (...props) => {
+        for (let prop of props) {
+          let val = aRow.getResultByName(prop);
+          if (val !== null) {
+            item[prop] = val;
+          }
+        }
+      };
+      copyProps("guid", "title", "index", "dateAdded", "lastModified");
+      if (aIncludeParentGuid) {
+        copyProps("parentGuid");
+      }
+
+      let itemId = aRow.getResultByName("id");
+      if (aOptions.includeItemIds) {
+        item.id = itemId;
+      }
+
+      let type = aRow.getResultByName("type");
+      item.typeCode = type;
+      if (type == Ci.nsINavBookmarksService.TYPE_BOOKMARK) {
+        copyProps("charset", "tags", "iconUri");
+      }
+
+      switch (type) {
+        case PlacesUtils.bookmarks.TYPE_BOOKMARK:
+          item.type = PlacesUtils.TYPE_X_MOZ_PLACE;
+          // If this throws due to an invalid url, the item will be skipped.
+          try {
+            item.uri = new URL(aRow.getResultByName("url")).href;
+          } catch (ex) {
+            let error = new Error("Invalid bookmark URL");
+            error.becauseInvalidURL = true;
+            throw error;
+          }
+          // Keywords are cached, so this should be decently fast.
+          let entry = await PlacesUtils.keywords.fetch({ url: item.uri });
+          if (entry) {
+            item.keyword = entry.keyword;
+            item.postData = entry.postData;
+          }
+          break;
+        case PlacesUtils.bookmarks.TYPE_FOLDER:
+          item.type = PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER;
+          // Mark root folders.
+          if (item.guid == PlacesUtils.bookmarks.rootGuid) {
+            item.root = "placesRoot";
+          } else if (item.guid == PlacesUtils.bookmarks.menuGuid) {
+            item.root = "bookmarksMenuFolder";
+          } else if (item.guid == PlacesUtils.bookmarks.unfiledGuid) {
+            item.root = "unfiledBookmarksFolder";
+          } else if (item.guid == PlacesUtils.bookmarks.toolbarGuid) {
+            item.root = "toolbarFolder";
+          } else if (item.guid == PlacesUtils.bookmarks.mobileGuid) {
+            item.root = "mobileFolder";
+          }
+          break;
+        case PlacesUtils.bookmarks.TYPE_SEPARATOR:
+          item.type = PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR;
+          break;
+        default:
+          console.error(`Unexpected bookmark type ${type}`);
+          break;
+      }
+      return item;
+    };
+
+    const QUERY_STR = `/* do not warn (bug no): cannot use an index */
+       WITH RECURSIVE
+       descendants(fk, level, type, id, guid, parent, parentGuid, position,
+                   title, dateAdded, lastModified) AS (
+         SELECT b1.fk, 0, b1.type, b1.id, b1.guid, b1.parent,
+                (SELECT guid FROM moz_bookmarks WHERE id = b1.parent),
+                b1.position, b1.title, b1.dateAdded, b1.lastModified
+         FROM moz_bookmarks b1 WHERE b1.guid=:item_guid
+         UNION ALL
+         SELECT b2.fk, level + 1, b2.type, b2.id, b2.guid, b2.parent,
+                descendants.guid, b2.position, b2.title, b2.dateAdded,
+                b2.lastModified
+         FROM moz_bookmarks b2
+         JOIN descendants ON b2.parent = descendants.id AND b2.id <> :tags_folder),
+       tagged(place_id, tags) AS (
+         SELECT b.fk, group_concat(p.title ORDER BY p.title)
+         FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON p.id = b.parent
+         JOIN moz_bookmarks g ON g.id = p.parent
+         WHERE g.guid = '${PlacesUtils.bookmarks.tagsGuid}'
+         GROUP BY b.fk
+       )
+       SELECT d.level, d.id, d.guid, d.parent, d.parentGuid, d.type,
+              d.position AS [index], IFNULL(d.title, '') AS title, d.dateAdded,
+              d.lastModified, h.url, (SELECT icon_url FROM moz_icons i
+                      JOIN moz_icons_to_pages ON icon_id = i.id
+                      JOIN moz_pages_w_icons pi ON page_id = pi.id
+                      WHERE pi.page_url_hash = hash(h.url) AND pi.page_url = h.url
+                      ORDER BY width DESC LIMIT 1) AS iconUri,
+              (SELECT tags FROM tagged WHERE place_id = h.id) AS tags,
+              (SELECT a.content FROM moz_annos a
+               JOIN moz_anno_attributes n ON a.anno_attribute_id = n.id
+               WHERE place_id = h.id AND n.name = :charset_anno
+              ) AS charset
+       FROM descendants d
+       LEFT JOIN moz_bookmarks b3 ON b3.id = d.parent
+       LEFT JOIN moz_places h ON h.id = d.fk
+       ORDER BY d.level, d.parent, d.position`;
+
+    if (!aItemGuid) {
+      aItemGuid = this.bookmarks.rootGuid;
+    }
+
+    let hasExcludeItemsCallback = aOptions.hasOwnProperty(
+      "excludeItemsCallback"
+    );
+    let excludedParents = new Set();
+    let shouldExcludeItem = (aItem, aParentGuid) => {
+      let exclude =
+        excludedParents.has(aParentGuid) ||
+        aOptions.excludeItemsCallback(aItem);
+      if (exclude) {
+        if (aItem.type == this.TYPE_X_MOZ_PLACE_CONTAINER) {
+          excludedParents.add(aItem.guid);
+        }
+      }
+      return exclude;
+    };
+
+    let rootItem = null;
+    let parentsMap = new Map();
+    let conn = await this.promiseDBConnection();
+    let rows = await conn.executeCached(QUERY_STR, {
+      tags_folder: PlacesUtils.tagsFolderId,
+      charset_anno: PlacesUtils.CHARSET_ANNO,
+      item_guid: aItemGuid,
+    });
+    let yieldCounter = 0;
+    for (let row of rows) {
+      let item;
+      if (!rootItem) {
+        try {
+          // This is the first row.
+          rootItem = item = await createItemInfoObject(row, true);
+          Object.defineProperty(rootItem, "itemsCount", {
+            value: 1,
+            writable: true,
+            enumerable: false,
+            configurable: false,
+          });
+        } catch (ex) {
+          console.error("Failed to fetch the data for the root item");
+          throw ex;
+        }
+      } else {
+        try {
+          // Our query guarantees that we always visit parents ahead of their
+          // children.
+          item = await createItemInfoObject(row, false);
+          let parentGuid = row.getResultByName("parentGuid");
+          if (hasExcludeItemsCallback && shouldExcludeItem(item, parentGuid)) {
+            continue;
+          }
+
+          let parentItem = parentsMap.get(parentGuid);
+          if ("children" in parentItem) {
+            parentItem.children.push(item);
+          } else {
+            parentItem.children = [item];
+          }
+
+          rootItem.itemsCount++;
+        } catch (ex) {
+          // This is a bogus child, report and skip it.
+          console.error("Failed to fetch the data for an item ", ex);
+          continue;
+        }
+      }
+
+      if (item.type == this.TYPE_X_MOZ_PLACE_CONTAINER) {
+        parentsMap.set(item.guid, item);
+      }
+
+      // With many bookmarks we end up stealing the CPU - even with yielding!
+      // So we let everyone else have a go every few items (bug 1186714).
+      if (++yieldCounter % 50 == 0) {
+        await new Promise(resolve => {
+          Services.tm.dispatchToMainThread(resolve);
+        });
+      }
+    }
+
+    return rootItem;
+  },
+
+  /**
+   * Returns a generator that iterates over `array` and yields slices of no
+   * more than `chunkLength` elements at a time.
+   *
+   * @param  {Array} array An array containing zero or more elements.
+   * @param  {number} chunkLength The maximum number of elements in each chunk.
+   * @yields {Array} A chunk of the array.
+   * @throws if `chunkLength` is negative or not an integer.
+   */
+  *chunkArray(array, chunkLength) {
+    if (chunkLength <= 0 || !Number.isInteger(chunkLength)) {
+      throw new TypeError("Chunk length must be a positive integer");
+    }
+    if (!array.length) {
+      return;
+    }
+    if (array.length <= chunkLength) {
+      yield array;
+      return;
+    }
+    let startIndex = 0;
+    while (startIndex < array.length) {
+      yield array.slice(startIndex, (startIndex += chunkLength));
+    }
+  },
+
+  /**
+   * Returns SQL placeholders to bind multiple values into an IN clause.
+   * @param {Array|number} info
+   *   Array or number of entries to create.
+   * @param {string} [prefix]
+   *   String prefix to add before the SQL param.
+   * @param {string} [suffix]
+   *   String suffix to add after the SQL param.
+   */
+  sqlBindPlaceholders(info, prefix = "", suffix = "") {
+    let length = Array.isArray(info) ? info.length : info;
+    return new Array(length).fill(prefix + "?" + suffix).join(",");
+  },
+
+  /**
+   * Run some text through md5 and return the hash.
+   * @param {string} data The string to hash.
+   * @param {string} [format] Which format of the hash to return:
+   *   - "ascii" for ascii format.
+   *   - "hex" for hex format.
+   * @returns {string} hash of the input string in the required format.
+   * @deprecated use sha256 instead.
+   */
+  md5(data, { format = "ascii" } = {}) {
+    let hasher = new lazy.CryptoHash("md5");
+
+    // Convert the data to a byte array for hashing.
+    data = new TextEncoder().encode(data);
+    hasher.update(data, data.length);
+    switch (format) {
+      case "hex":
+        let hash = hasher.finish(false);
+        return Array.from(hash, (c, i) =>
+          hash.charCodeAt(i).toString(16).padStart(2, "0")
+        ).join("");
+      case "ascii":
+      default:
+        return hasher.finish(true);
+    }
+  },
+
+  /**
+   * Run some text through SHA256 and return the hash.
+   * @param {string} data The string to hash.
+   * @param {string} [format] Which format of the hash to return:
+   *   - "ascii" for ascii format.
+   *   - "hex" for hex format.
+   * @returns {string} hash of the input string in the required format.
+   */
+  sha256(data, { format = "ascii" } = {}) {
+    let hasher = new lazy.CryptoHash("sha256");
+
+    // Convert the data to a byte array for hashing.
+    data = new TextEncoder().encode(data);
+    hasher.update(data, data.length);
+    switch (format) {
+      case "hex":
+        let hash = hasher.finish(false);
+        return Array.from(hash, (c, i) =>
+          hash.charCodeAt(i).toString(16).padStart(2, "0")
+        ).join("");
+      case "ascii":
+      default:
+        return hasher.finish(true);
+    }
+  },
+
+  /**
+   * Inserts a new place if one doesn't currently exist.
+   *
+   * This should only be used from an API that is connecting this new entry to
+   * some additional foreign table. Otherwise this will just create an orphan
+   * entry that could be expired at any time.
+   *
+   * @param db
+   *        The database connection to use.
+   * @param url
+   *        A valid URL object.
+   * @return {Promise} resolved when the operation is complete.
+   */
+  async maybeInsertPlace(db, url) {
+    // The IGNORE conflict can trigger on `guid`.
+    await db.executeCached(
+      `INSERT OR IGNORE INTO moz_places (url, url_hash, rev_host, hidden, frecency, guid)
+      VALUES (:url, hash(:url), :rev_host,
+              (CASE WHEN :url BETWEEN 'place:' AND 'place:' || X'FFFF' THEN 1 ELSE 0 END),
+              :frecency,
+              IFNULL((SELECT guid FROM moz_places WHERE url_hash = hash(:url) AND url = :url),
+                      GENERATE_GUID()))
+      `,
+      {
+        url: url.href,
+        rev_host: this.getReversedHost(url),
+        frecency: url.protocol == "place:" ? 0 : -1,
+      }
+    );
+  },
+
+  /**
+   * Tries to insert a set of new places if they don't exist yet.
+   *
+   * This should only be used from an API that is connecting this new entry to
+   * some additional foreign table. Otherwise this will just create an orphan
+   * entry that could be expired at any time.
+   *
+   * @param db
+   *        The database to use
+   * @param urls
+   *        An array with all the url objects to insert.
+   * @return {Promise} resolved when the operation is complete.
+   */
+  async maybeInsertManyPlaces(db, urls) {
+    await db.executeCached(
+      `INSERT OR IGNORE INTO moz_places (url, url_hash, rev_host, hidden, frecency, guid) VALUES
+     (:url, hash(:url), :rev_host,
+     (CASE WHEN :url BETWEEN 'place:' AND 'place:' || X'FFFF' THEN 1 ELSE 0 END),
+     :frecency,
+     IFNULL((SELECT guid FROM moz_places WHERE url_hash = hash(:url) AND url = :url), :maybeguid))`,
+      urls.map(url => ({
+        url: url.href,
+        rev_host: this.getReversedHost(url),
+        frecency: url.protocol == "place:" ? 0 : -1,
+        maybeguid: this.history.makeGuid(),
+      }))
+    );
+  },
+
+  /**
+   * Can be used to detect being in automation to allow specific code paths
+   * that are normally disallowed.
+   */
+  get isInAutomation() {
+    return (
+      Cu.isInAutomation || Services.env.exists("XPCSHELL_TEST_PROFILE_DIR")
+    );
+  },
+
+  /**
+   * Creates a logger.
+   * Logging level can be controlled through places.loglevel.
+   *
+   * @param {string} [prefix] Prefix to use for the logged messages, "::" will
+   *                 be appended automatically to the prefix.
+   * @returns {object} The logger.
+   */
+  getLogger({ prefix = "" } = {}) {
+    if (!this._logger) {
+      this._logger = lazy.Log.repository.getLogger("places");
+      this._logger.manageLevelFromPref("places.loglevel");
+      this._logger.addAppender(
+        new lazy.Log.ConsoleAppender(new lazy.Log.BasicFormatter())
+      );
+    }
+    if (prefix) {
+      // This is not an early return because it is necessary to invoke getLogger
+      // at least once before getLoggerWithMessagePrefix; it replaces a
+      // method of the original logger, rather than using an actual Proxy.
+      return lazy.Log.repository.getLoggerWithMessagePrefix(
+        "places",
+        prefix + " :: "
+      );
+    }
+    return this._logger;
+  },
+};
+
+ChromeUtils.defineLazyGetter(PlacesUtils, "history", function () {
+  let hs = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+    Ci.nsINavHistoryService
+  );
+  return Object.freeze(
+    new Proxy(hs, {
+      get(target, name) {
+        let property, object;
+        if (name in target) {
+          property = target[name];
+          object = target;
+        } else {
+          property = lazy.History[name];
+          object = lazy.History;
+        }
+        if (typeof property == "function") {
+          return property.bind(object);
+        }
+        return property;
+      },
+      set(target, name, val) {
+        // Forward to the XPCOM object, otherwise don't allow to set properties.
+        if (name in target) {
+          target[name] = val;
+          return true;
+        }
+        // This will throw in strict mode.
+        return false;
+      },
+    })
+  );
+});
+
+XPCOMUtils.defineLazyServiceGetter(
+  PlacesUtils,
+  "favicons",
+  "@mozilla.org/browser/favicon-service;1",
+  "nsIFaviconService"
+);
+
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "bmsvc",
+  "@mozilla.org/browser/nav-bookmarks-service;1",
+  "nsINavBookmarksService"
+);
+ChromeUtils.defineLazyGetter(PlacesUtils, "bookmarks", () => {
+  return Object.freeze(
+    new Proxy(lazy.Bookmarks, {
+      get: (target, name) =>
+        lazy.Bookmarks.hasOwnProperty(name)
+          ? lazy.Bookmarks[name]
+          : lazy.bmsvc[name],
+    })
+  );
+});
+
+XPCOMUtils.defineLazyServiceGetter(
+  PlacesUtils,
+  "tagging",
+  "@mozilla.org/browser/tagging-service;1",
+  "nsITaggingService"
+);
+
+ChromeUtils.defineLazyGetter(lazy, "bundle", function () {
+  const PLACES_STRING_BUNDLE_URI = "chrome://places/locale/places.properties";
+  return Services.strings.createBundle(PLACES_STRING_BUNDLE_URI);
+});
+
+// This is just used as a reasonably-random value for copy & paste / drag operations.
+ChromeUtils.defineLazyGetter(PlacesUtils, "instanceId", () => {
+  return PlacesUtils.history.makeGuid();
+});
+
+/**
+ * Setup internal databases for closing properly during shutdown.
+ *
+ * 1. Places initiates shutdown.
+ * 2. Before places can move to the step where it closes the low-level connection,
+ *   we need to make sure that we have closed `conn`.
+ * 3. Before we can close `conn`, we need to make sure that all external clients
+ *   have stopped using `conn`.
+ * 4. Before we can close Sqlite, we need to close `conn`.
+ */
+function setupDbForShutdown(conn, name) {
+  try {
+    let state = "0. Not started.";
+    let promiseClosed = new Promise((resolve, reject) => {
+      // The service initiates shutdown.
+      // Before it can safely close its connection, we need to make sure
+      // that we have closed the high-level connection.
+      try {
+        PlacesUtils.history.connectionShutdownClient.jsclient.addBlocker(
+          `${name} closing as part of Places shutdown`,
+          async function () {
+            state = "1. Service has initiated shutdown";
+
+            // At this stage, all external clients have finished using the
+            // database. We just need to close the high-level connection.
+            try {
+              await conn.close();
+              state = "2. Closed Sqlite.sys.mjs connection.";
+              resolve();
+            } catch (ex) {
+              state = "2. Failed to closed Sqlite.sys.mjs connection: " + ex;
+              reject(ex);
+            }
+          },
+          () => state
+        );
+      } catch (ex) {
+        // It's too late to block shutdown, just close the connection.
+        conn.close();
+        reject(ex);
+      }
+    }).catch(console.error);
+
+    // Make sure that Sqlite.sys.mjs doesn't close until we are done
+    // with the high-level connection.
+    lazy.Sqlite.shutdown.addBlocker(
+      `${name} must be closed before Sqlite.sys.mjs`,
+      () => promiseClosed,
+      () => state
+    );
+  } catch (ex) {
+    // It's too late to block shutdown, just close the connection.
+    conn.close();
+    throw ex;
+  }
+}
+
+ChromeUtils.defineLazyGetter(lazy, "gAsyncDBConnPromised", () =>
+  lazy.Sqlite.cloneStorageConnection({
+    connection: PlacesUtils.history.DBConnection,
+    readOnly: true,
+  })
+    .then(conn => {
+      setupDbForShutdown(conn, "PlacesUtils read-only connection");
+      return conn;
+    })
+    .catch(console.error)
+);
+
+ChromeUtils.defineLazyGetter(lazy, "gAsyncDBWrapperPromised", () =>
+  lazy.Sqlite.wrapStorageConnection({
+    connection: PlacesUtils.history.DBConnection,
+  })
+    .then(conn => {
+      setupDbForShutdown(conn, "PlacesUtils wrapped connection");
+      return conn;
+    })
+    .catch(console.error)
+);
+
+var gAsyncDBLargeCacheConnDeferred = Promise.withResolvers();
+ChromeUtils.defineLazyGetter(lazy, "gAsyncDBLargeCacheConnPromised", () =>
+  lazy.Sqlite.cloneStorageConnection({
+    connection: PlacesUtils.history.DBConnection,
+    readOnly: true,
+  })
+    .then(async conn => {
+      setupDbForShutdown(conn, "PlacesUtils large cache read-only connection");
+      // Components like the urlbar often fallback to a table scan due to lack
+      // of full text indices.  A larger cache helps reducing IO and improves
+      // performance. This value is expected to be larger than the default
+      // mozStorage value defined as MAX_CACHE_SIZE_BYTES in
+      // storage/mozStorageConnection.cpp.
+      await conn.execute("PRAGMA cache_size = -6144"); // 6MiB
+      // These should be kept in sync with nsPlacesTables.h.
+      await conn.execute(`
+        CREATE TEMP TABLE IF NOT EXISTS moz_openpages_temp (
+          url TEXT,
+          userContextId INTEGER,
+          open_count INTEGER,
+          PRIMARY KEY (url, userContextId)
+        )`);
+      await conn.execute(`
+        CREATE TEMP TRIGGER IF NOT EXISTS moz_openpages_temp_afterupdate_trigger
+        AFTER UPDATE OF open_count ON moz_openpages_temp FOR EACH ROW
+        WHEN NEW.open_count = 0
+        BEGIN
+          DELETE FROM moz_openpages_temp
+          WHERE url = NEW.url
+            AND userContextId = NEW.userContextId;
+        END`);
+      gAsyncDBLargeCacheConnDeferred.resolve(conn);
+      return conn;
+    })
+    .catch(console.error)
+);
+
+/**
+ * The metadata API allows consumers to store simple key-value metadata in
+ * Places. Keys are strings, values can be any type that SQLite supports:
+ * numbers (integers and doubles), Booleans, strings, and blobs. Values are
+ * cached in memory for faster lookups.
+ *
+ * Since some consumers set metadata as part of an existing operation or active
+ * transaction, the API also exposes a `*withConnection` variant for each
+ * method that takes an open database connection.
+ */
+PlacesUtils.metadata = {
+  cache: new Map(),
+  jsonPrefix: "data:application/json;base64,",
+
+  /**
+   * Returns the value associated with a metadata key.
+   *
+   * @param  {String} key
+   *         The metadata key to look up.
+   * @param  {String|Object|Array} defaultValue
+   *         Optional. The default value to return if the value is not present,
+   *         or cannot be parsed.
+   * @resolves {*}
+   *         The value associated with the key, or the defaultValue if there is one.
+   * @rejects
+   *         Rejected if the value is not found or it cannot be parsed
+   *         and there is no defaultValue.
+   */
+  get(key, defaultValue) {
+    return PlacesUtils.withConnectionWrapper("PlacesUtils.metadata.get", db =>
+      this.getWithConnection(db, key, defaultValue)
+    );
+  },
+
+  /**
+   * Sets the value for a metadata key.
+   *
+   * @param {String} key
+   *        The metadata key to update.
+   * @param {*}
+   *        The value to associate with the key.
+   */
+  set(key, value) {
+    return PlacesUtils.withConnectionWrapper("PlacesUtils.metadata.set", db =>
+      this.setWithConnection(db, new Map([[key, value]]))
+    );
+  },
+
+  /**
+   * Sets the value for multiple keys.
+   *
+   * @param {Map} pairs
+   *        The metadata keys to update, with their value.
+   */
+  setMany(pairs) {
+    return PlacesUtils.withConnectionWrapper("PlacesUtils.metadata.set", db =>
+      this.setWithConnection(db, pairs)
+    );
+  },
+
+  /**
+   * Removes the values for the given metadata keys.
+   *
+   * @param {String...}
+   *        One or more metadata keys to remove.
+   */
+  delete(...keys) {
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.metadata.delete",
+      db => this.deleteWithConnection(db, ...keys)
+    );
+  },
+
+  async getWithConnection(db, key, defaultValue) {
+    key = this.canonicalizeKey(key);
+    if (this.cache.has(key)) {
+      return this.cache.get(key);
+    }
+    let rows = await db.executeCached(
+      `
+      SELECT value FROM moz_meta WHERE key = :key`,
+      { key }
+    );
+    let value = null;
+    if (rows.length) {
+      let row = rows[0];
+      let rawValue = row.getResultByName("value");
+      // Convert blobs back to `Uint8Array`s.
+      if (row.getTypeOfIndex(0) == row.VALUE_TYPE_BLOB) {
+        value = new Uint8Array(rawValue);
+      } else if (
+        typeof rawValue == "string" &&
+        rawValue.startsWith(this.jsonPrefix)
+      ) {
+        try {
+          value = JSON.parse(
+            this._base64Decode(rawValue.substr(this.jsonPrefix.length))
+          );
+        } catch (ex) {
+          if (defaultValue !== undefined) {
+            // We must create a new array in the local scope to avoid a memory
+            // leak due to the array global object.
+            value = Cu.cloneInto(defaultValue, {});
+          } else {
+            throw ex;
+          }
+        }
+      } else {
+        value = rawValue;
+      }
+    } else if (defaultValue !== undefined) {
+      // We must create a new array in the local scope to avoid a memory leak due
+      // to the array global object.
+      value = Cu.cloneInto(defaultValue, {});
+    } else {
+      throw new Error(`No data stored for key ${key}`);
+    }
+    this.cache.set(key, value);
+    return value;
+  },
+
+  async setWithConnection(db, pairs) {
+    let entriesToSet = [];
+    let keysToDelete = Array.from(pairs.entries())
+      .filter(([key, value]) => {
+        if (value !== null) {
+          entriesToSet.push({ key: this.canonicalizeKey(key), value });
+          return false;
+        }
+        return true;
+      })
+      .map(([key, value]) => key);
+    if (keysToDelete.length) {
+      await this.deleteWithConnection(db, ...keysToDelete);
+      if (keysToDelete.length == pairs.size) {
+        return;
+      }
+    }
+
+    // Generate key{i}, value{i} pairs for the SQL bindings.
+    let params = entriesToSet.reduce((accumulator, { key, value }, i) => {
+      accumulator[`key${i}`] = key;
+      // Convert Objects to base64 JSON urls.
+      accumulator[`value${i}`] =
+        typeof value == "object" &&
+        ChromeUtils.getClassName(value) != "Uint8Array"
+          ? this.jsonPrefix + this._base64Encode(JSON.stringify(value))
+          : value;
+      return accumulator;
+    }, {});
+    await db.executeCached(
+      "REPLACE INTO moz_meta (key, value) VALUES " +
+        entriesToSet.map((e, i) => `(:key${i}, :value${i})`).join(),
+      params
+    );
+
+    // Update the cache.
+    entriesToSet.forEach(({ key, value }) => {
+      this.cache.set(key, value);
+    });
+  },
+
+  async deleteWithConnection(db, ...keys) {
+    keys = keys.map(this.canonicalizeKey);
+    if (!keys.length) {
+      return;
+    }
+    await db.execute(
+      `
+      DELETE FROM moz_meta
+      WHERE key IN (${new Array(keys.length).fill("?").join(",")})`,
+      keys
+    );
+    for (let key of keys) {
+      this.cache.delete(key);
+    }
+  },
+
+  canonicalizeKey(key) {
+    if (typeof key != "string" || !/^[a-zA-Z0-9\/_]+$/.test(key)) {
+      throw new TypeError("Invalid metadata key: " + key);
+    }
+    return key.toLowerCase();
+  },
+
+  _base64Encode(str) {
+    return ChromeUtils.base64URLEncode(new TextEncoder().encode(str), {
+      pad: true,
+    });
+  },
+
+  _base64Decode(str) {
+    return new TextDecoder("utf-8").decode(
+      ChromeUtils.base64URLDecode(str, { padding: "require" })
+    );
+  },
+};
+
+/**
+ * Keywords management API.
+ * Sooner or later these keywords will merge with search aliases, this is an
+ * interim API that should then be replaced by a unified one.
+ * Keywords are associated with URLs and can have POST data.
+ * The relations between URLs and keywords are the following:
+ *  - 1 keyword can only point to 1 URL
+ *  - 1 URL can have multiple keywords, iff they differ by POST data (included the empty one).
+ */
+PlacesUtils.keywords = {
+  /**
+   * Fetches a keyword entry based on keyword or URL.
+   *
+   * @param keywordOrEntry
+   *        Either the keyword to fetch or an entry providing keyword
+   *        or url property to find keywords for.  If both properties are set,
+   *        this returns their intersection.
+   * @param onResult [optional]
+   *        Callback invoked for each found entry.
+   * @return {Promise}
+   * @resolves to an object in the form: { keyword, url, postData },
+   *           or null if a keyword entry was not found.
+   */
+  fetch(keywordOrEntry, onResult = null) {
+    if (typeof keywordOrEntry == "string") {
+      keywordOrEntry = { keyword: keywordOrEntry };
+    }
+
+    if (
+      keywordOrEntry === null ||
+      typeof keywordOrEntry != "object" ||
+      ("keyword" in keywordOrEntry && typeof keywordOrEntry.keyword != "string")
+    ) {
+      throw new Error("Invalid keyword");
+    }
+
+    let hasKeyword = "keyword" in keywordOrEntry;
+    let hasUrl = "url" in keywordOrEntry;
+
+    if (!hasKeyword && !hasUrl) {
+      throw new Error("At least keyword or url must be provided");
+    }
+    if (onResult && typeof onResult != "function") {
+      throw new Error("onResult callback must be a valid function");
+    }
+
+    if (hasUrl) {
+      try {
+        keywordOrEntry.url = BOOKMARK_VALIDATORS.url(keywordOrEntry.url);
+      } catch (ex) {
+        throw new Error(keywordOrEntry.url + " is not a valid URL");
+      }
+    }
+    if (hasKeyword) {
+      keywordOrEntry.keyword = keywordOrEntry.keyword.trim().toLowerCase();
+    }
+
+    let safeOnResult = entry => {
+      if (onResult) {
+        try {
+          onResult(entry);
+        } catch (ex) {
+          console.error(ex);
+        }
+      }
+    };
+
+    return promiseKeywordsCache().then(cache => {
+      let entries = [];
+      if (hasKeyword) {
+        let entry = cache.get(keywordOrEntry.keyword);
+        if (entry) {
+          entries.push(entry);
+        }
+      }
+      if (hasUrl) {
+        for (let entry of cache.values()) {
+          if (entry.url.href == keywordOrEntry.url.href) {
+            entries.push(entry);
+          }
+        }
+      }
+
+      entries = entries.filter(e => {
+        return (
+          (!hasUrl || e.url.href == keywordOrEntry.url.href) &&
+          (!hasKeyword || e.keyword == keywordOrEntry.keyword)
+        );
+      });
+
+      entries.forEach(safeOnResult);
+      return entries.length ? entries[0] : null;
+    });
+  },
+
+  /**
+   * Adds a new keyword and postData for the given URL.
+   *
+   * @param keywordEntry
+   *        An object describing the keyword to insert, in the form:
+   *        {
+   *          keyword: non-empty string,
+   *          url: URL or href to associate to the keyword,
+   *          postData: optional POST data to associate to the keyword
+   *          source: The change source, forwarded to all bookmark observers.
+   *            Defaults to nsINavBookmarksService::SOURCE_DEFAULT.
+   *        }
+   * @note Do not define a postData property if there isn't any POST data.
+   *       Defining an empty string for POST data is equivalent to not having it.
+   * @resolves when the addition is complete.
+   */
+  insert(keywordEntry) {
+    if (!keywordEntry || typeof keywordEntry != "object") {
+      throw new Error("Input should be a valid object");
+    }
+
+    if (
+      !("keyword" in keywordEntry) ||
+      !keywordEntry.keyword ||
+      typeof keywordEntry.keyword != "string"
+    ) {
+      throw new Error("Invalid keyword");
+    }
+    if (
+      "postData" in keywordEntry &&
+      keywordEntry.postData &&
+      typeof keywordEntry.postData != "string"
+    ) {
+      throw new Error("Invalid POST data");
+    }
+    if (!("url" in keywordEntry)) {
+      throw new Error("undefined is not a valid URL");
+    }
+
+    if (!("source" in keywordEntry)) {
+      keywordEntry.source = PlacesUtils.bookmarks.SOURCES.DEFAULT;
+    }
+    let { keyword, url, source } = keywordEntry;
+    keyword = keyword.trim().toLowerCase();
+    let postData = keywordEntry.postData || "";
+    // This also checks href for validity
+    try {
+      url = BOOKMARK_VALIDATORS.url(url);
+    } catch (ex) {
+      throw new Error(url + " is not a valid URL");
+    }
+
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.keywords.insert",
+      async db => {
+        let cache = await promiseKeywordsCache();
+
+        // Trying to set the same keyword is a no-op.
+        let oldEntry = cache.get(keyword);
+        if (
+          oldEntry &&
+          oldEntry.url.href == url.href &&
+          (oldEntry.postData || "") == postData
+        ) {
+          return;
+        }
+
+        // A keyword can only be associated to a single page.
+        // If another page is using the new keyword, we must update the keyword
+        // entry.
+        // Note we cannot use INSERT OR REPLACE cause it wouldn't invoke the delete
+        // trigger.
+        if (oldEntry) {
+          await db.executeCached(
+            `UPDATE moz_keywords
+             SET place_id = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url),
+                 post_data = :post_data
+             WHERE keyword = :keyword
+            `,
+            { url: url.href, keyword, post_data: postData }
+          );
+          await notifyKeywordChange(oldEntry.url.href, "", source);
+        } else {
+          // An entry for the given page could be missing, in such a case we need to
+          // create it.  The IGNORE conflict can trigger on `guid`.
+          await db.executeTransaction(async () => {
+            await PlacesUtils.maybeInsertPlace(db, url);
+
+            // A new keyword could be assigned to an url that already has one,
+            // then we must replace the old keyword with the new one.
+            let oldKeywords = [];
+            for (let entry of cache.values()) {
+              if (
+                entry.url.href == url.href &&
+                (entry.postData || "") == postData
+              ) {
+                oldKeywords.push(entry.keyword);
+              }
+            }
+            if (oldKeywords.length) {
+              for (let oldKeyword of oldKeywords) {
+                await db.executeCached(
+                  `DELETE FROM moz_keywords WHERE keyword = :oldKeyword`,
+                  { oldKeyword }
+                );
+                cache.delete(oldKeyword);
+              }
+            }
+
+            await db.executeCached(
+              `INSERT INTO moz_keywords (keyword, place_id, post_data)
+               VALUES (:keyword, (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url), :post_data)
+              `,
+              { url: url.href, keyword, post_data: postData }
+            );
+
+            await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+              db,
+              url,
+              lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(source)
+            );
+          });
+        }
+
+        cache.set(keyword, { keyword, url, postData: postData || null });
+
+        // In any case, notify about the new keyword.
+        await notifyKeywordChange(url.href, keyword, source);
+      }
+    );
+  },
+
+  /**
+   * Removes a keyword.
+   *
+   * @param keyword
+   *        The keyword to remove.
+   * @return {Promise}
+   * @resolves when the removal is complete.
+   */
+  remove(keywordOrEntry) {
+    if (typeof keywordOrEntry == "string") {
+      keywordOrEntry = {
+        keyword: keywordOrEntry,
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      };
+    }
+
+    if (
+      keywordOrEntry === null ||
+      typeof keywordOrEntry != "object" ||
+      !keywordOrEntry.keyword ||
+      typeof keywordOrEntry.keyword != "string"
+    ) {
+      throw new Error("Invalid keyword");
+    }
+
+    let { keyword, source = Ci.nsINavBookmarksService.SOURCE_DEFAULT } =
+      keywordOrEntry;
+    keyword = keywordOrEntry.keyword.trim().toLowerCase();
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.keywords.remove",
+      async db => {
+        let cache = await promiseKeywordsCache();
+        if (!cache.has(keyword)) {
+          return;
+        }
+        let { url } = cache.get(keyword);
+        cache.delete(keyword);
+
+        await db.executeTransaction(async function () {
+          await db.execute(
+            `DELETE FROM moz_keywords WHERE keyword = :keyword`,
+            { keyword }
+          );
+
+          await lazy.PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL(
+            db,
+            url,
+            lazy.PlacesSyncUtils.bookmarks.determineSyncChangeDelta(source)
+          );
+        });
+
+        // Notify bookmarks about the removal.
+        await notifyKeywordChange(url.href, "", source);
+      }
+    );
+  },
+
+  /**
+   * Moves all (keyword, POST data) pairs from one URL to another, and fires
+   * observer notifications for all affected bookmarks. If the destination URL
+   * already has keywords, they will be removed and replaced with the source
+   * URL's keywords.
+   *
+   * @param oldURL
+   *        The source URL.
+   * @param newURL
+   *        The destination URL.
+   * @param source
+   *        The change source, forwarded to all bookmark observers.
+   * @return {Promise}
+   * @resolves when all keywords have been moved to the destination URL.
+   */
+  reassign(oldURL, newURL, source = PlacesUtils.bookmarks.SOURCES.DEFAULT) {
+    try {
+      oldURL = BOOKMARK_VALIDATORS.url(oldURL);
+    } catch (ex) {
+      throw new Error(oldURL + " is not a valid source URL");
+    }
+    try {
+      newURL = BOOKMARK_VALIDATORS.url(newURL);
+    } catch (ex) {
+      throw new Error(oldURL + " is not a valid destination URL");
+    }
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.keywords.reassign",
+      async function (db) {
+        let keywordsToReassign = [];
+        let keywordsToRemove = [];
+        let cache = await promiseKeywordsCache();
+        for (let [keyword, entry] of cache) {
+          if (entry.url.href == oldURL.href) {
+            keywordsToReassign.push(keyword);
+          }
+          if (entry.url.href == newURL.href) {
+            keywordsToRemove.push(keyword);
+          }
+        }
+        if (!keywordsToReassign.length) {
+          return;
+        }
+
+        await db.executeTransaction(async function () {
+          // Remove existing keywords from the new URL.
+          await db.executeCached(
+            `DELETE FROM moz_keywords WHERE keyword = :keyword`,
+            keywordsToRemove.map(keyword => ({ keyword }))
+          );
+
+          // Move keywords from the old URL to the new URL.
+          await db.executeCached(
+            `
+          UPDATE moz_keywords SET
+            place_id = (SELECT id FROM moz_places
+                        WHERE url_hash = hash(:newURL) AND
+                              url = :newURL)
+          WHERE place_id = (SELECT id FROM moz_places
+                            WHERE url_hash = hash(:oldURL) AND
+                                  url = :oldURL)`,
+            { newURL: newURL.href, oldURL: oldURL.href }
+          );
+        });
+        for (let keyword of keywordsToReassign) {
+          let entry = cache.get(keyword);
+          entry.url = newURL;
+        }
+        for (let keyword of keywordsToRemove) {
+          cache.delete(keyword);
+        }
+
+        if (keywordsToReassign.length) {
+          // If we moved any keywords, notify that we removed all keywords from
+          // the old and new URLs, then notify for each moved keyword.
+          await notifyKeywordChange(oldURL, "", source);
+          await notifyKeywordChange(newURL, "", source);
+          for (let keyword of keywordsToReassign) {
+            await notifyKeywordChange(newURL, keyword, source);
+          }
+        } else if (keywordsToRemove.length) {
+          // If the old URL didn't have any keywords, but the new URL did, just
+          // notify that we removed all keywords from the new URL.
+          await notifyKeywordChange(oldURL, "", source);
+        }
+      }
+    );
+  },
+
+  /**
+   * Removes all orphaned keywords from the given URLs. Orphaned keywords are
+   * associated with URLs that are no longer bookmarked. If a given URL is still
+   * bookmarked, its keywords will not be removed.
+   *
+   * @param urls
+   *        A list of URLs to check for orphaned keywords.
+   * @return {Promise}
+   * @resolves when all keywords have been removed from URLs that are no longer
+   *           bookmarked.
+   */
+  removeFromURLsIfNotBookmarked(urls) {
+    let hrefs = new Set();
+    for (let url of urls) {
+      try {
+        url = BOOKMARK_VALIDATORS.url(url);
+      } catch (ex) {
+        throw new Error(url + " is not a valid URL");
+      }
+      hrefs.add(url.href);
+    }
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.keywords.removeFromURLsIfNotBookmarked",
+      async function (db) {
+        let keywordsByHref = new Map();
+        let cache = await promiseKeywordsCache();
+        for (let [keyword, entry] of cache) {
+          let href = entry.url.href;
+          if (!hrefs.has(href)) {
+            continue;
+          }
+          if (!keywordsByHref.has(href)) {
+            keywordsByHref.set(href, [keyword]);
+            continue;
+          }
+          let existingKeywords = keywordsByHref.get(href);
+          existingKeywords.push(keyword);
+        }
+        if (!keywordsByHref.size) {
+          return;
+        }
+
+        let placeInfosToRemove = [];
+        let rows = await db.execute(
+          `
+          SELECT h.id, h.url
+          FROM moz_places h
+          JOIN moz_keywords k ON k.place_id = h.id
+          GROUP BY h.id
+          HAVING h.foreign_count = count(*) +
+            (SELECT count(*)
+             FROM moz_bookmarks b
+             JOIN moz_bookmarks p ON b.parent = p.id
+             WHERE p.parent = :tags_root AND b.fk = h.id)
+          `,
+          { tags_root: PlacesUtils.tagsFolderId }
+        );
+        for (let row of rows) {
+          placeInfosToRemove.push({
+            placeId: row.getResultByName("id"),
+            href: row.getResultByName("url"),
+          });
+        }
+        if (!placeInfosToRemove.length) {
+          return;
+        }
+
+        await db.execute(
+          `DELETE FROM moz_keywords WHERE place_id IN (${Array.from(
+            placeInfosToRemove.map(info => info.placeId)
+          ).join()})`
+        );
+        for (let { href } of placeInfosToRemove) {
+          let keywords = keywordsByHref.get(href);
+          for (let keyword of keywords) {
+            cache.delete(keyword);
+          }
+        }
+      }
+    );
+  },
+
+  /**
+   * Removes all keywords from all URLs.
+   *
+   * @return {Promise}
+   * @resolves when all keywords have been removed.
+   */
+  eraseEverything() {
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils.keywords.eraseEverything",
+      async function (db) {
+        let cache = await promiseKeywordsCache();
+        if (!cache.size) {
+          return;
+        }
+        await db.executeCached(`DELETE FROM moz_keywords`);
+        cache.clear();
+      }
+    );
+  },
+
+  /**
+   * Invalidates the keywords cache, leaving all existing keywords in place.
+   * The cache will be repopulated on the next `PlacesUtils.keywords.*` call.
+   *
+   * @return {Promise}
+   * @resolves when the cache has been cleared.
+   */
+  invalidateCachedKeywords() {
+    gKeywordsCachePromise = gKeywordsCachePromise.then(_ => null);
+    this.ensureCacheInitialized();
+    return gKeywordsCachePromise;
+  },
+
+  /**
+   * Ensures the keywords cache is initialized.
+   */
+  async ensureCacheInitialized() {
+    this._cache = await promiseKeywordsCache();
+  },
+
+  /**
+   * Checks from the cache if a given word is a bookmark keyword.
+   * We must make sure the cache is populated, and await ensureCacheInitialized()
+   * before calling this function.
+   *
+   * @return {Boolean} Whether the given word is a keyword.
+   */
+  isKeywordFromCache(keyword) {
+    return this._cache?.has(keyword);
+  },
+};
+
+var gKeywordsCachePromise = Promise.resolve();
+
+function promiseKeywordsCache() {
+  let promise = gKeywordsCachePromise.then(function (cache) {
+    if (cache) {
+      return cache;
+    }
+    return PlacesUtils.withConnectionWrapper(
+      "PlacesUtils: promiseKeywordsCache",
+      async db => {
+        let cache = new Map();
+        let rows = await db.execute(
+          `SELECT keyword, url, post_data
+           FROM moz_keywords k
+           JOIN moz_places h ON h.id = k.place_id
+          `
+        );
+        let brokenKeywords = [];
+        for (let row of rows) {
+          let keyword = row.getResultByName("keyword");
+          try {
+            let entry = {
+              keyword,
+              url: new URL(row.getResultByName("url")),
+              postData: row.getResultByName("post_data") || null,
+            };
+            cache.set(keyword, entry);
+          } catch (ex) {
+            // The url is invalid, don't load the keyword and remove it, or it
+            // would break the whole keywords API.
+            brokenKeywords.push(keyword);
+          }
+        }
+        if (brokenKeywords.length) {
+          await db.execute(
+            `DELETE FROM moz_keywords
+             WHERE keyword IN (${brokenKeywords.map(JSON.stringify).join(",")})
+            `
+          );
+        }
+        return cache;
+      }
+    );
+  });
+  gKeywordsCachePromise = promise.catch(_ => {});
+  return promise;
+}
diff --git a/toolkit/components/places/SQLFunctions.cpp b/toolkit/components/places/SQLFunctions.cpp
new file mode 100644
index 0000000000..e625f3fa09
--- /dev/null
+++ b/toolkit/components/places/SQLFunctions.cpp
@@ -0,0 +1,1520 @@
+/* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/storage.h"
+#include "mozilla/StaticPrefs_places.h"
+#include "nsString.h"
+#include "nsFaviconService.h"
+#include "nsNavBookmarks.h"
+#include "nsUnicharUtils.h"
+#include "nsWhitespaceTokenizer.h"
+#include "nsEscape.h"
+#include "mozIPlacesAutoComplete.h"
+#include "SQLFunctions.h"
+#include "nsMathUtils.h"
+#include "nsUnicodeProperties.h"
+#include "nsUTF8Utils.h"
+#include "nsINavHistoryService.h"
+#include "nsPrintfCString.h"
+#include "nsNavHistory.h"
+#include "mozilla/Likely.h"
+#include "mozilla/Services.h"
+#include "mozilla/Utf8.h"
+#include "nsURLHelper.h"
+#include "nsVariant.h"
+#include "nsICryptoHash.h"
+
+// Maximum number of chars to search through.
+// MatchAutoCompleteFunction won't look for matches over this threshold.
+#define MAX_CHARS_TO_SEARCH_THROUGH 255
+
+#define SECONDS_PER_DAY 86400
+
+using namespace mozilla::storage;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Anonymous Helpers
+
+namespace {
+
+using const_char_iterator = nsACString::const_char_iterator;
+using size_type = nsACString::size_type;
+using char_type = nsACString::char_type;
+
+/**
+ * Scan forward through UTF-8 text until the next potential character that
+ * could match a given codepoint when lower-cased (false positives are okay).
+ * This avoids having to actually parse the UTF-8 text, which is slow.
+ *
+ * @param aStart
+ *        An iterator pointing to the first character position considered.
+ *        It will be updated by this function.
+ * @param aEnd
+ *        An interator pointing to past-the-end of the string.
+ */
+static MOZ_ALWAYS_INLINE void goToNextSearchCandidate(
+    const_char_iterator& aStart, const const_char_iterator& aEnd,
+    uint32_t aSearchFor) {
+  // If the character we search for is ASCII, then we can scan until we find
+  // it or its ASCII uppercase character, modulo the special cases
+  // U+0130 LATIN CAPITAL LETTER I WITH DOT ABOVE and U+212A KELVIN SIGN
+  // (which are the only non-ASCII characters that lower-case to ASCII ones).
+  // Since false positives are okay, we approximate ASCII lower-casing by
+  // bit-ORing with 0x20, for increased performance.
+  //
+  // If the character we search for is *not* ASCII, we can ignore everything
+  // that is, since all ASCII characters lower-case to ASCII.
+  //
+  // Because of how UTF-8 uses high-order bits, this will never land us
+  // in the middle of a codepoint.
+  //
+  // The assumptions about Unicode made here are verified in the test_casing
+  // gtest.
+  if (aSearchFor < 128) {
+    // When searching for I or K, we pick out the first byte of the UTF-8
+    // encoding of the corresponding special case character, and look for it
+    // in the loop below.  For other characters we fall back to 0xff, which
+    // is not a valid UTF-8 byte.
+    unsigned char target = (unsigned char)(aSearchFor | 0x20);
+    unsigned char special = 0xff;
+    if (target == 'i' || target == 'k') {
+      special = (target == 'i' ? 0xc4 : 0xe2);
+    }
+
+    while (aStart < aEnd && (unsigned char)(*aStart | 0x20) != target &&
+           (unsigned char)*aStart != special) {
+      aStart++;
+    }
+  } else {
+    while (aStart < aEnd && (unsigned char)(*aStart) < 128) {
+      aStart++;
+    }
+  }
+}
+
+/**
+ * Check whether a character position is on a word boundary of a UTF-8 string
+ * (rather than within a word).  We define "within word" to be any position
+ * between [a-zA-Z] and [a-z] -- this lets us match CamelCase words.
+ * TODO: support non-latin alphabets.
+ *
+ * @param aPos
+ *        An iterator pointing to the character position considered.  It must
+ *        *not* be the first byte of a string.
+ *
+ * @return true if boundary, false otherwise.
+ */
+static MOZ_ALWAYS_INLINE bool isOnBoundary(const_char_iterator aPos) {
+  if ('a' <= *aPos && *aPos <= 'z') {
+    char prev = static_cast<char>(*(aPos - 1) | 0x20);
+    return !('a' <= prev && prev <= 'z');
+  }
+  return true;
+}
+
+/**
+ * Check whether a token string matches a particular position of a source
+ * string, case insensitively (or optionally, case and diacritic insensitively).
+ *
+ * @param aTokenStart
+ *        An iterator pointing to the start of the token string.
+ * @param aTokenEnd
+ *        An iterator pointing past-the-end of the token string.
+ * @param aSourceStart
+ *        An iterator pointing to the position of source string to start
+ *        matching at.
+ * @param aSourceEnd
+ *        An iterator pointing past-the-end of the source string.
+ * @param aMatchDiacritics
+ *        Whether or not the match is diacritic-sensitive.
+ *
+ * @return true if the string [aTokenStart, aTokenEnd) matches the start of
+ *         the string [aSourceStart, aSourceEnd, false otherwise.
+ */
+static MOZ_ALWAYS_INLINE bool stringMatch(const_char_iterator aTokenStart,
+                                          const_char_iterator aTokenEnd,
+                                          const_char_iterator aSourceStart,
+                                          const_char_iterator aSourceEnd,
+                                          bool aMatchDiacritics) {
+  const_char_iterator tokenCur = aTokenStart, sourceCur = aSourceStart;
+
+  while (tokenCur < aTokenEnd) {
+    if (sourceCur >= aSourceEnd) {
+      return false;
+    }
+
+    bool error;
+    if (!CaseInsensitiveUTF8CharsEqual(sourceCur, tokenCur, aSourceEnd,
+                                       aTokenEnd, &sourceCur, &tokenCur, &error,
+                                       aMatchDiacritics)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+enum FindInStringBehavior { eFindOnBoundary, eFindAnywhere };
+
+/**
+ * Common implementation for findAnywhere and findOnBoundary.
+ *
+ * @param aToken
+ *        The token we're searching for
+ * @param aSourceString
+ *        The string in which we're searching
+ * @param aBehavior
+ *        eFindOnBoundary if we should only consider matchines which occur on
+ *        word boundaries, or eFindAnywhere if we should consider matches
+ *        which appear anywhere.
+ *
+ * @return true if aToken was found in aSourceString, false otherwise.
+ */
+static bool findInString(const nsDependentCSubstring& aToken,
+                         const nsACString& aSourceString,
+                         FindInStringBehavior aBehavior) {
+  // GetLowerUTF8Codepoint assumes that there's at least one byte in
+  // the string, so don't pass an empty token here.
+  MOZ_ASSERT(!aToken.IsEmpty(), "Don't search for an empty token!");
+
+  // We cannot match anything if there is nothing to search.
+  if (aSourceString.IsEmpty()) {
+    return false;
+  }
+
+  const nsNavHistory* history = nsNavHistory::GetConstHistoryService();
+  bool matchDiacritics = history && history->MatchDiacritics();
+
+  const_char_iterator tokenStart(aToken.BeginReading()),
+      tokenEnd(aToken.EndReading()), tokenNext,
+      sourceStart(aSourceString.BeginReading()),
+      sourceEnd(aSourceString.EndReading()), sourceCur(sourceStart), sourceNext;
+
+  uint32_t tokenFirstChar =
+      GetLowerUTF8Codepoint(tokenStart, tokenEnd, &tokenNext);
+  if (tokenFirstChar == uint32_t(-1)) {
+    return false;
+  }
+  if (!matchDiacritics) {
+    tokenFirstChar = ToNaked(tokenFirstChar);
+  }
+
+  for (;;) {
+    if (matchDiacritics) {
+      // Scan forward to the next viable candidate (if any).
+      goToNextSearchCandidate(sourceCur, sourceEnd, tokenFirstChar);
+    }
+    if (sourceCur == sourceEnd) {
+      break;
+    }
+
+    // Check whether the first character in the token matches the character
+    // at sourceCur.  At the same time, get a pointer to the next character
+    // in the source.
+    uint32_t sourceFirstChar =
+        GetLowerUTF8Codepoint(sourceCur, sourceEnd, &sourceNext);
+    if (sourceFirstChar == uint32_t(-1)) {
+      return false;
+    }
+    if (!matchDiacritics) {
+      sourceFirstChar = ToNaked(sourceFirstChar);
+    }
+
+    if (sourceFirstChar == tokenFirstChar &&
+        (aBehavior != eFindOnBoundary || sourceCur == sourceStart ||
+         isOnBoundary(sourceCur)) &&
+        stringMatch(tokenNext, tokenEnd, sourceNext, sourceEnd,
+                    matchDiacritics)) {
+      return true;
+    }
+
+    sourceCur = sourceNext;
+  }
+
+  return false;
+}
+
+static MOZ_ALWAYS_INLINE nsDependentCString
+getSharedUTF8String(mozIStorageValueArray* aValues, uint32_t aIndex) {
+  uint32_t len;
+  const char* str = aValues->AsSharedUTF8String(aIndex, &len);
+  if (!str) {
+    return nsDependentCString("", (size_t)0);
+  }
+  return nsDependentCString(str, len);
+}
+
+/**
+ * Gets the length of the prefix in a URI spec.  "Prefix" is defined to be the
+ * scheme, colon, and, if present, two slashes.
+ *
+ * Examples:
+ *
+ *   http://example.com
+ *   ~~~~~~~
+ *   => length == 7
+ *
+ *   foo:example
+ *   ~~~~
+ *   => length == 4
+ *
+ *   not a spec
+ *   => length == 0
+ *
+ * @param  aSpec
+ *         A URI spec, or a string that may be a URI spec.
+ * @return The length of the prefix in the spec.  If there isn't a prefix,
+ *         returns 0.
+ */
+static MOZ_ALWAYS_INLINE size_type getPrefixLength(const nsACString& aSpec) {
+  // To keep the search bounded, look at 64 characters at most.  The longest
+  // IANA schemes are ~30, so double that and round up to a nice number.
+  size_type length = std::min(static_cast<size_type>(64), aSpec.Length());
+  for (size_type i = 0; i < length; ++i) {
+    if (aSpec[i] == static_cast<char_type>(':')) {
+      // Found the ':'.  Now skip past "//", if present.
+      if (i + 2 < aSpec.Length() &&
+          aSpec[i + 1] == static_cast<char_type>('/') &&
+          aSpec[i + 2] == static_cast<char_type>('/')) {
+        i += 2;
+      }
+      return i + 1;
+    }
+  }
+  return 0;
+}
+
+/**
+ * Gets the index in a URI spec of the host and port substring and optionally
+ * its length.
+ *
+ * Examples:
+ *
+ *   http://example.com/
+ *          ~~~~~~~~~~~
+ *   => index == 7, length == 11
+ *
+ *   http://example.com:8888/
+ *          ~~~~~~~~~~~~~~~~
+ *   => index == 7, length == 16
+ *
+ *   http://user:pass@example.com/
+ *                    ~~~~~~~~~~~
+ *   => index == 17, length == 11
+ *
+ *   foo:example
+ *       ~~~~~~~
+ *   => index == 4, length == 7
+ *
+ *   not a spec
+ *   ~~~~~~~~~~
+ *   => index == 0, length == 10
+ *
+ * @param  aSpec
+ *         A URI spec, or a string that may be a URI spec.
+ * @param  _hostAndPortLength
+ *         The length of the host and port substring is returned through this
+ *         param.  Pass null if you don't care.
+ * @return The length of the host and port substring in the spec.  If aSpec
+ *         doesn't look like a URI, then the entire aSpec is assumed to be a
+ *         "host and port", and this returns 0, and _hostAndPortLength will be
+ *         the length of aSpec.
+ */
+static MOZ_ALWAYS_INLINE size_type
+indexOfHostAndPort(const nsACString& aSpec, size_type* _hostAndPortLength) {
+  size_type index = getPrefixLength(aSpec);
+  size_type i = index;
+  for (; i < aSpec.Length(); ++i) {
+    // RFC 3986 (URIs): The origin ("authority") is terminated by '/', '?', or
+    // '#' (or the end of the URI).
+    if (aSpec[i] == static_cast<char_type>('/') ||
+        aSpec[i] == static_cast<char_type>('?') ||
+        aSpec[i] == static_cast<char_type>('#')) {
+      break;
+    }
+    // RFC 3986: '@' marks the end of the userinfo component.
+    if (aSpec[i] == static_cast<char_type>('@')) {
+      index = i + 1;
+    }
+  }
+  if (_hostAndPortLength) {
+    *_hostAndPortLength = i - index;
+  }
+  return index;
+}
+
+}  // End anonymous namespace
+
+namespace mozilla::places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// AutoComplete Matching Function
+
+/* static */
+nsresult MatchAutoCompleteFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<MatchAutoCompleteFunction> function = new MatchAutoCompleteFunction();
+
+  nsresult rv = aDBConn->CreateFunction("autocomplete_match"_ns,
+                                        kArgIndexLength, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+/* static */
+nsDependentCSubstring MatchAutoCompleteFunction::fixupURISpec(
+    const nsACString& aURISpec, int32_t aMatchBehavior, nsACString& aSpecBuf) {
+  nsDependentCSubstring fixedSpec;
+
+  // Try to unescape the string.  If that succeeds and yields a different
+  // string which is also valid UTF-8, we'll use it.
+  // Otherwise, we will simply use our original string.
+  bool unescaped =
+      NS_UnescapeURL(aURISpec.BeginReading(), (int32_t)aURISpec.Length(),
+                     esc_SkipControl, aSpecBuf);
+  if (unescaped && IsUtf8(aSpecBuf)) {
+    fixedSpec.Rebind(aSpecBuf, 0);
+  } else {
+    fixedSpec.Rebind(aURISpec, 0);
+  }
+
+  if (aMatchBehavior == mozIPlacesAutoComplete::MATCH_ANYWHERE_UNMODIFIED) {
+    return fixedSpec;
+  }
+
+  if (StringBeginsWith(fixedSpec, "http://"_ns)) {
+    fixedSpec.Rebind(fixedSpec, 7);
+  } else if (StringBeginsWith(fixedSpec, "https://"_ns)) {
+    fixedSpec.Rebind(fixedSpec, 8);
+  } else if (StringBeginsWith(fixedSpec, "ftp://"_ns)) {
+    fixedSpec.Rebind(fixedSpec, 6);
+  }
+
+  return fixedSpec;
+}
+
+/* static */
+bool MatchAutoCompleteFunction::findAnywhere(
+    const nsDependentCSubstring& aToken, const nsACString& aSourceString) {
+  // We can't use FindInReadable here; it works only for ASCII.
+
+  return findInString(aToken, aSourceString, eFindAnywhere);
+}
+
+/* static */
+bool MatchAutoCompleteFunction::findOnBoundary(
+    const nsDependentCSubstring& aToken, const nsACString& aSourceString) {
+  return findInString(aToken, aSourceString, eFindOnBoundary);
+}
+
+/* static */
+MatchAutoCompleteFunction::searchFunctionPtr
+MatchAutoCompleteFunction::getSearchFunction(int32_t aBehavior) {
+  switch (aBehavior) {
+    case mozIPlacesAutoComplete::MATCH_ANYWHERE:
+    case mozIPlacesAutoComplete::MATCH_ANYWHERE_UNMODIFIED:
+      return findAnywhere;
+    case mozIPlacesAutoComplete::MATCH_BOUNDARY:
+    default:
+      return findOnBoundary;
+  };
+}
+
+NS_IMPL_ISUPPORTS(MatchAutoCompleteFunction, mozIStorageFunction)
+
+MatchAutoCompleteFunction::MatchAutoCompleteFunction()
+    : mCachedZero(new IntegerVariant(0)), mCachedOne(new IntegerVariant(1)) {
+  static_assert(IntegerVariant::HasThreadSafeRefCnt::value,
+                "Caching assumes that variants have thread-safe refcounting");
+}
+
+NS_IMETHODIMP
+MatchAutoCompleteFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                          nsIVariant** _result) {
+  // Macro to make the code a bit cleaner and easier to read.  Operates on
+  // searchBehavior.
+  int32_t searchBehavior = aArguments->AsInt32(kArgIndexSearchBehavior);
+#define HAS_BEHAVIOR(aBitName) \
+  (searchBehavior & mozIPlacesAutoComplete::BEHAVIOR_##aBitName)
+
+  nsDependentCString searchString =
+      getSharedUTF8String(aArguments, kArgSearchString);
+  nsDependentCString url = getSharedUTF8String(aArguments, kArgIndexURL);
+
+  int32_t matchBehavior = aArguments->AsInt32(kArgIndexMatchBehavior);
+
+  // We only want to filter javascript: URLs if we are not supposed to search
+  // for them, and the search does not start with "javascript:".
+  if (matchBehavior != mozIPlacesAutoComplete::MATCH_ANYWHERE_UNMODIFIED &&
+      StringBeginsWith(url, "javascript:"_ns) && !HAS_BEHAVIOR(JAVASCRIPT) &&
+      !StringBeginsWith(searchString, "javascript:"_ns)) {
+    *_result = do_AddRef(mCachedZero).take();
+    return NS_OK;
+  }
+
+  int32_t visitCount = aArguments->AsInt32(kArgIndexVisitCount);
+  // Filtering on typed is no more used by Firefox, it is still being used by
+  // comm-central clients.
+  bool typed = aArguments->AsInt32(kArgIndexTyped) != 0;
+  bool bookmark = aArguments->AsInt32(kArgIndexBookmark) != 0;
+  nsDependentCString tags = getSharedUTF8String(aArguments, kArgIndexTags);
+  int32_t openPageCount = aArguments->AsInt32(kArgIndexOpenPageCount);
+  bool matches = false;
+  if (HAS_BEHAVIOR(RESTRICT)) {
+    // Make sure we match all the filter requirements.  If a given restriction
+    // is active, make sure the corresponding condition is not true.
+    matches = (!HAS_BEHAVIOR(HISTORY) || visitCount > 0) &&
+              (!HAS_BEHAVIOR(TYPED) || typed) &&
+              (!HAS_BEHAVIOR(BOOKMARK) || bookmark) &&
+              (!HAS_BEHAVIOR(TAG) || !tags.IsVoid()) &&
+              (!HAS_BEHAVIOR(OPENPAGE) || openPageCount > 0);
+  } else {
+    // Make sure that we match all the filter requirements and that the
+    // corresponding condition is true if at least a given restriction is
+    // active.
+    matches = (HAS_BEHAVIOR(HISTORY) && visitCount > 0) ||
+              (HAS_BEHAVIOR(TYPED) && typed) ||
+              (HAS_BEHAVIOR(BOOKMARK) && bookmark) ||
+              (HAS_BEHAVIOR(TAG) && !tags.IsVoid()) ||
+              (HAS_BEHAVIOR(OPENPAGE) && openPageCount > 0);
+  }
+
+  if (!matches) {
+    *_result = do_AddRef(mCachedZero).take();
+    return NS_OK;
+  }
+
+  // Obtain our search function.
+  searchFunctionPtr searchFunction = getSearchFunction(matchBehavior);
+
+  // Clean up our URI spec and prepare it for searching.
+  nsCString fixedUrlBuf;
+  nsDependentCSubstring fixedUrl =
+      fixupURISpec(url, matchBehavior, fixedUrlBuf);
+  // Limit the number of chars we search through.
+  const nsDependentCSubstring& trimmedUrl =
+      Substring(fixedUrl, 0, MAX_CHARS_TO_SEARCH_THROUGH);
+
+  nsDependentCString title = getSharedUTF8String(aArguments, kArgIndexTitle);
+  // Limit the number of chars we search through.
+  const nsDependentCSubstring& trimmedTitle =
+      Substring(title, 0, MAX_CHARS_TO_SEARCH_THROUGH);
+
+  // Caller may pass a fallback title, for example in case of bookmarks or
+  // snapshots, one may want to search both the user provided title and the
+  // history one.
+  nsDependentCString fallbackTitle =
+      getSharedUTF8String(aArguments, kArgIndexFallbackTitle);
+  // Limit the number of chars we search through.
+  const nsDependentCSubstring& trimmedFallbackTitle =
+      Substring(fallbackTitle, 0, MAX_CHARS_TO_SEARCH_THROUGH);
+
+  // Determine if every token matches either the bookmark title, tags, page
+  // title, or page URL.
+  nsCWhitespaceTokenizer tokenizer(searchString);
+  while (matches && tokenizer.hasMoreTokens()) {
+    const nsDependentCSubstring& token = tokenizer.nextToken();
+
+    if (HAS_BEHAVIOR(TITLE) && HAS_BEHAVIOR(URL)) {
+      matches = (searchFunction(token, trimmedTitle) ||
+                 searchFunction(token, trimmedFallbackTitle) ||
+                 searchFunction(token, tags)) &&
+                searchFunction(token, trimmedUrl);
+    } else if (HAS_BEHAVIOR(TITLE)) {
+      matches = searchFunction(token, trimmedTitle) ||
+                searchFunction(token, trimmedFallbackTitle) ||
+                searchFunction(token, tags);
+    } else if (HAS_BEHAVIOR(URL)) {
+      matches = searchFunction(token, trimmedUrl);
+    } else {
+      matches = searchFunction(token, trimmedTitle) ||
+                searchFunction(token, trimmedFallbackTitle) ||
+                searchFunction(token, tags) ||
+                searchFunction(token, trimmedUrl);
+    }
+  }
+
+  *_result = do_AddRef(matches ? mCachedOne : mCachedZero).take();
+  return NS_OK;
+#undef HAS_BEHAVIOR
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Frecency Calculation Function
+
+/* static */
+nsresult CalculateFrecencyFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<CalculateFrecencyFunction> function = new CalculateFrecencyFunction();
+
+  nsresult rv = aDBConn->CreateFunction("calculate_frecency"_ns, -1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(CalculateFrecencyFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+CalculateFrecencyFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                          nsIVariant** _result) {
+  // Fetch arguments.  Use default values if they were omitted.
+  uint32_t numEntries;
+  nsresult rv = aArguments->GetNumEntries(&numEntries);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numEntries <= 2, "unexpected number of arguments");
+
+  int64_t pageId = aArguments->AsInt64(0);
+  MOZ_ASSERT(pageId > 0, "Should always pass a valid page id");
+  if (pageId <= 0) {
+    *_result = MakeAndAddRef<IntegerVariant>(0).take();
+    return NS_OK;
+  }
+
+  enum RedirectBonus { eUnknown, eRedirect, eNormal };
+
+  RedirectBonus mostRecentVisitBonus = eUnknown;
+
+  if (numEntries > 1) {
+    mostRecentVisitBonus = aArguments->AsInt32(1) ? eRedirect : eNormal;
+  }
+
+  int32_t typed = 0;
+  int32_t visitCount = 0;
+  PRTime mostRecentBookmarkTime = 0;
+  int32_t isQuery = 0;
+  float pointsForSampledVisits = 0.0f;
+  int32_t numSampledVisits = 0;
+  int32_t bonus = 0;
+
+  // This is a const version of the history object for thread-safety.
+  const nsNavHistory* history = nsNavHistory::GetConstHistoryService();
+  NS_ENSURE_STATE(history);
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+
+  // Fetch the page stats from the database.
+  {
+    nsCOMPtr<mozIStorageStatement> getPageInfo = DB->GetStatement(
+        "SELECT typed, visit_count, MAX(dateAdded), "
+        "(substr(url, 0, 7) = 'place:') "
+        "FROM moz_places h "
+        "LEFT JOIN moz_bookmarks ON fk = h.id "
+        "WHERE h.id = :page_id");
+    NS_ENSURE_STATE(getPageInfo);
+    mozStorageStatementScoper infoScoper(getPageInfo);
+
+    rv = getPageInfo->BindInt64ByName("page_id"_ns, pageId);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    bool hasResult = false;
+    rv = getPageInfo->ExecuteStep(&hasResult);
+    NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hasResult, NS_ERROR_UNEXPECTED);
+
+    rv = getPageInfo->GetInt32(0, &typed);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = getPageInfo->GetInt32(1, &visitCount);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = getPageInfo->GetInt64(2, &mostRecentBookmarkTime);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = getPageInfo->GetInt32(3, &isQuery);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (visitCount > 0) {
+    // Get a sample of the last visits to the page, to calculate its weight.
+    // In case the visit is a redirect target, calculate the frecency
+    // as if the original page was visited.
+    // If it's a redirect source, we may want to use a lower bonus.
+    nsCString redirectsTransitionFragment = nsPrintfCString(
+        "%d AND %d ", nsINavHistoryService::TRANSITION_REDIRECT_PERMANENT,
+        nsINavHistoryService::TRANSITION_REDIRECT_TEMPORARY);
+    nsCOMPtr<mozIStorageStatement> getVisits = DB->GetStatement(
+        nsLiteralCString(
+            "/* do not warn (bug 659740 - SQLite may ignore index if few "
+            "visits exist) */"
+            "SELECT "
+            "IFNULL(origin.visit_type, v.visit_type) AS visit_type, "
+            "target.visit_type AS target_visit_type, "
+            "ROUND((strftime('%s','now','localtime','utc') - "
+            "v.visit_date/1000000)/86400) AS age_in_days, "
+            "v.source AS visit_source "
+            "FROM moz_historyvisits v "
+            "LEFT JOIN moz_historyvisits origin ON origin.id = v.from_visit "
+            "AND v.visit_type BETWEEN ") +
+        redirectsTransitionFragment +
+        nsLiteralCString(
+            "LEFT JOIN moz_historyvisits target ON v.id = target.from_visit "
+            "AND target.visit_type BETWEEN ") +
+        redirectsTransitionFragment +
+        nsLiteralCString("WHERE v.place_id = :page_id "
+                         "ORDER BY v.visit_date DESC "
+                         "LIMIT :max_visits "));
+    NS_ENSURE_STATE(getVisits);
+    mozStorageStatementScoper visitsScoper(getVisits);
+    rv = getVisits->BindInt64ByName("page_id"_ns, pageId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = getVisits->BindInt32ByName("max_visits"_ns,
+                                    history->GetNumVisitsForFrecency());
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Fetch only a limited number of recent visits.
+    bool hasResult = false;
+    while (NS_SUCCEEDED(getVisits->ExecuteStep(&hasResult)) && hasResult) {
+      // If this is a redirect target, we'll use the visitType of the source,
+      // otherwise the actual visitType.
+      int32_t visitType = getVisits->AsInt32(0);
+
+      // When adding a new visit, we should haved passed-in whether we should
+      // use the redirect bonus. We can't fetch this information from the
+      // database, because we only store redirect targets.
+      // For older visits we extract the value from the database.
+      bool useRedirectBonus = mostRecentVisitBonus == eRedirect;
+      if (mostRecentVisitBonus == eUnknown || numSampledVisits > 0) {
+        int32_t targetVisitType = getVisits->AsInt32(1);
+        useRedirectBonus =
+            targetVisitType ==
+                nsINavHistoryService::TRANSITION_REDIRECT_PERMANENT ||
+            (targetVisitType ==
+                 nsINavHistoryService::TRANSITION_REDIRECT_TEMPORARY &&
+             visitType != nsINavHistoryService::TRANSITION_TYPED);
+      }
+
+      uint32_t visitSource = getVisits->AsInt32(3);
+      if (mostRecentBookmarkTime) {
+        // For bookmarked visit, add full bonus.
+        bonus = history->GetFrecencyTransitionBonus(visitType, true,
+                                                    useRedirectBonus);
+        bonus += history->GetFrecencyTransitionBonus(
+            nsINavHistoryService::TRANSITION_BOOKMARK, true);
+      } else if (visitSource == nsINavHistoryService::VISIT_SOURCE_ORGANIC) {
+        bonus = history->GetFrecencyTransitionBonus(visitType, true,
+                                                    useRedirectBonus);
+      } else if (visitSource == nsINavHistoryService::VISIT_SOURCE_SEARCHED) {
+        bonus = history->GetFrecencyTransitionBonus(
+            nsINavHistoryService::TRANSITION_LINK, true, useRedirectBonus);
+      }
+
+      // If bonus was zero, we can skip the work to determine the weight.
+      if (bonus) {
+        int32_t ageInDays = getVisits->AsInt32(2);
+        int32_t weight = history->GetFrecencyAgedWeight(ageInDays);
+        pointsForSampledVisits += ((float)weight * ((float)bonus / 100.0f));
+      }
+
+      numSampledVisits++;
+    }
+  }
+
+  // If we sampled some visits for this page, use the calculated weight.
+  if (numSampledVisits) {
+    // We were unable to calculate points, maybe cause all the visits in the
+    // sample had a zero bonus. Though, we know the page has some past valid
+    // visit, or visit_count would be zero. Thus we set the frecency to
+    // -1, so they are still shown in autocomplete.
+    if (pointsForSampledVisits == 0.0f) {
+      *_result = MakeAndAddRef<IntegerVariant>(-1).take();
+    } else {
+      // Estimate frecency using the sampled visits.
+      // Use ceilf() so that we don't round down to 0, which
+      // would cause us to completely ignore the place during autocomplete.
+      *_result =
+          MakeAndAddRef<IntegerVariant>(
+              (int32_t)ceilf((float)visitCount * ceilf(pointsForSampledVisits) /
+                             (float)numSampledVisits))
+              .take();
+    }
+    return NS_OK;
+  }
+
+  // Otherwise this page has no visits, it may be bookmarked.
+  if (!mostRecentBookmarkTime || isQuery) {
+    *_result = MakeAndAddRef<IntegerVariant>(0).take();
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(bonus == 0, "Pages should arrive here with 0 bonus");
+  MOZ_ASSERT(mostRecentBookmarkTime > 0, "This should be a bookmarked page");
+
+  // For unvisited bookmarks, produce a non-zero frecency, so that they show
+  // up in URL bar autocomplete.
+  // Make it so something bookmarked and typed will have a higher frecency
+  // than something just typed or just bookmarked.
+  bonus += history->GetFrecencyTransitionBonus(
+      nsINavHistoryService::TRANSITION_BOOKMARK, false);
+  if (typed) {
+    bonus += history->GetFrecencyTransitionBonus(
+        nsINavHistoryService::TRANSITION_TYPED, false);
+  }
+
+  // Use an appropriate bucket depending on the bookmark creation date.
+  int32_t bookmarkAgeInDays =
+      static_cast<int32_t>((PR_Now() - mostRecentBookmarkTime) /
+                           ((PRTime)SECONDS_PER_DAY * (PRTime)PR_USEC_PER_SEC));
+
+  pointsForSampledVisits =
+      (float)history->GetFrecencyAgedWeight(bookmarkAgeInDays) *
+      ((float)bonus / 100.0f);
+
+  // use ceilf() so that we don't round down to 0, which
+  // would cause us to completely ignore the place during autocomplete
+  *_result =
+      MakeAndAddRef<IntegerVariant>((int32_t)ceilf(pointsForSampledVisits))
+          .take();
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Frecency Calculation Function
+
+/* static */
+nsresult CalculateAltFrecencyFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<CalculateAltFrecencyFunction> function =
+      new CalculateAltFrecencyFunction();
+
+  nsresult rv =
+      aDBConn->CreateFunction("calculate_alt_frecency"_ns, -1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(CalculateAltFrecencyFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+CalculateAltFrecencyFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                             nsIVariant** _result) {
+  // Fetch arguments.  Use default values if they were omitted.
+  uint32_t numEntries;
+  nsresult rv = aArguments->GetNumEntries(&numEntries);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numEntries <= 2, "unexpected number of arguments");
+
+  int64_t pageId = aArguments->AsInt64(0);
+  MOZ_ASSERT(pageId > 0, "Should always pass a valid page id");
+  if (pageId <= 0) {
+    *_result = MakeAndAddRef<IntegerVariant>(0).take();
+    return NS_OK;
+  }
+
+  int32_t isRedirect = 0;
+  if (numEntries > 1) {
+    isRedirect = aArguments->AsInt32(1);
+  }
+  // This is a const version of the history object for thread-safety.
+  const nsNavHistory* history = nsNavHistory::GetConstHistoryService();
+  NS_ENSURE_STATE(history);
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+
+  /*
+    Exponentially decay each visit with an half-life of halfLifeDays.
+    Score per each visit is a weight exponentially decayed depending on how
+    far away is from a reference date, that is the most recent visit date.
+    The weight for each visit is assigned depending on the visit type and other
+    information (bookmarked, a redirect, a typed entry).
+    If a page has no visits, consider a single visit with an high weight and
+    decay its score using the bookmark date as reference time.
+    Frecency is the sum of all the scores / number of samples.
+    The final score is further decayed using the same half-life.
+    To avoid having to decay the score manually, the stored value is the number
+    of days after which the score would become 1.
+
+    TODO: Add reference link to source docs here.
+  */
+  nsCOMPtr<mozIStorageStatement> stmt = DB->GetStatement(
+      "WITH "
+      "lambda (lambda) AS ( "
+      "  SELECT ln(2) / :halfLifeDays "
+      "), "
+      "visits (days, weight) AS ( "
+      "  SELECT "
+      "    v.visit_date / 86400000000, "
+      "    (SELECT CASE "
+      "      WHEN IFNULL(s.visit_type, v.visit_type) = 3 "  // from a bookmark
+      "        OR v.source = 2 "                            // is a bookmark
+      "        OR  ( IFNULL(s.visit_type, v.visit_type) = 2 "  // is typed
+      "          AND v.source <> 3 "                           // not a search
+      "          AND t.id IS NULL AND NOT :isRedirect "        // not a redirect
+      "        ) "
+      "      THEN :highWeight "
+      "      WHEN t.id IS NULL AND NOT :isRedirect "  // not a redirect
+      "       AND IFNULL(s.visit_type, v.visit_type) NOT IN (4, 8, 9) "
+      "      THEN :mediumWeight "
+      "      ELSE :lowWeight "
+      "     END) "
+      "  FROM moz_historyvisits v "
+      // If it's a redirect target, use the visit_type of the source.
+      "  LEFT JOIN moz_historyvisits s ON s.id = v.from_visit "
+      "                               AND v.visit_type IN (5,6) "
+      // If it's a redirect, use a low weight.
+      "  LEFT JOIN moz_historyvisits t ON t.from_visit = v.id "
+      "                               AND t.visit_type IN (5,6) "
+      "  WHERE v.place_id = :pageId "
+      "  ORDER BY v.visit_date DESC "
+      "  LIMIT :numSampledVisits "
+      "), "
+      "bookmark (days, weight) AS ( "
+      "  SELECT dateAdded / 86400000000, 100 "
+      "  FROM moz_bookmarks "
+      "  WHERE fk = :pageId "
+      "  ORDER BY dateAdded DESC "
+      "  LIMIT 1 "
+      "), "
+      "samples (days, weight) AS ( "
+      "  SELECT * FROM bookmark WHERE (SELECT count(*) FROM visits) = 0 "
+      "  UNION ALL "
+      "  SELECT * FROM visits "
+      "), "
+      "reference (days, samples_count) AS ( "
+      "  SELECT max(samples.days), count(*) FROM samples "
+      "), "
+      "scores (score) AS ( "
+      "  SELECT (weight * exp(-lambda * (samples.days - reference.days))) "
+      "  FROM samples, reference, lambda "
+      ") "
+      "SELECT CASE "
+      "WHEN (substr(url, 0, 7) = 'place:') THEN 0 "
+      "ELSE "
+      "  reference.days + CAST (( "
+      "    ln( "
+      "      sum(score) / samples_count * MAX(visit_count, samples_count) "
+      "    ) / lambda "
+      "  ) AS INTEGER) "
+      "END "
+      "FROM moz_places h, reference, lambda, scores "
+      "WHERE h.id = :pageId");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper infoScoper(stmt);
+
+  rv = stmt->BindInt64ByName("pageId"_ns, pageId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("isRedirect"_ns, isRedirect);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName(
+      "halfLifeDays"_ns,
+      StaticPrefs::places_frecency_pages_alternative_halfLifeDays_AtStartup());
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName(
+      "numSampledVisits"_ns,
+      StaticPrefs::
+          places_frecency_pages_alternative_numSampledVisits_AtStartup());
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName(
+      "lowWeight"_ns,
+      StaticPrefs::places_frecency_pages_alternative_lowWeight_AtStartup());
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName(
+      "mediumWeight"_ns,
+      StaticPrefs::places_frecency_pages_alternative_mediumWeight_AtStartup());
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName(
+      "highWeight"_ns,
+      StaticPrefs::places_frecency_pages_alternative_highWeight_AtStartup());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult = false;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && hasResult, NS_ERROR_UNEXPECTED);
+
+  bool isNull;
+  if (NS_SUCCEEDED(stmt->GetIsNull(0, &isNull)) && isNull) {
+    *_result = MakeAndAddRef<NullVariant>().take();
+  } else {
+    int32_t score;
+    rv = stmt->GetInt32(0, &score);
+    NS_ENSURE_SUCCESS(rv, rv);
+    *_result = MakeAndAddRef<IntegerVariant>(score).take();
+  }
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// GUID Creation Function
+
+/* static */
+nsresult GenerateGUIDFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<GenerateGUIDFunction> function = new GenerateGUIDFunction();
+  nsresult rv = aDBConn->CreateFunction("generate_guid"_ns, 0, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(GenerateGUIDFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+GenerateGUIDFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                     nsIVariant** _result) {
+  nsAutoCString guid;
+  nsresult rv = GenerateGUID(guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *_result = MakeAndAddRef<UTF8TextVariant>(guid).take();
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// GUID Validation Function
+
+/* static */
+nsresult IsValidGUIDFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<IsValidGUIDFunction> function = new IsValidGUIDFunction();
+  return aDBConn->CreateFunction("is_valid_guid"_ns, 1, function);
+}
+
+NS_IMPL_ISUPPORTS(IsValidGUIDFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+IsValidGUIDFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                    nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  nsAutoCString guid;
+  aArguments->GetUTF8String(0, guid);
+
+  RefPtr<nsVariant> result = new nsVariant();
+  result->SetAsBool(IsValidGUID(guid));
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get Unreversed Host Function
+
+/* static */
+nsresult GetUnreversedHostFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<GetUnreversedHostFunction> function = new GetUnreversedHostFunction();
+  nsresult rv = aDBConn->CreateFunction("get_unreversed_host"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(GetUnreversedHostFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+GetUnreversedHostFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                          nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  nsAutoString src;
+  aArguments->GetString(0, src);
+
+  RefPtr<nsVariant> result = new nsVariant();
+
+  if (src.Length() > 1) {
+    src.Truncate(src.Length() - 1);
+    nsAutoString dest;
+    ReverseString(src, dest);
+    result->SetAsAString(dest);
+  } else {
+    result->SetAsAString(u""_ns);
+  }
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Fixup URL Function
+
+/* static */
+nsresult FixupURLFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<FixupURLFunction> function = new FixupURLFunction();
+  nsresult rv = aDBConn->CreateFunction("fixup_url"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(FixupURLFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+FixupURLFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                 nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  nsAutoString src;
+  aArguments->GetString(0, src);
+
+  RefPtr<nsVariant> result = new nsVariant();
+
+  if (StringBeginsWith(src, u"http://"_ns)) {
+    src.Cut(0, 7);
+  } else if (StringBeginsWith(src, u"https://"_ns)) {
+    src.Cut(0, 8);
+  } else if (StringBeginsWith(src, u"ftp://"_ns)) {
+    src.Cut(0, 6);
+  }
+
+  // Remove common URL hostname prefixes
+  if (StringBeginsWith(src, u"www."_ns)) {
+    src.Cut(0, 4);
+  }
+
+  result->SetAsAString(src);
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Store Last Inserted Id Function
+
+/* static */
+nsresult StoreLastInsertedIdFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<StoreLastInsertedIdFunction> function =
+      new StoreLastInsertedIdFunction();
+  nsresult rv =
+      aDBConn->CreateFunction("store_last_inserted_id"_ns, 2, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(StoreLastInsertedIdFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+StoreLastInsertedIdFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                            nsIVariant** _result) {
+  uint32_t numArgs;
+  nsresult rv = aArgs->GetNumEntries(&numArgs);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numArgs == 2);
+
+  nsAutoCString table;
+  rv = aArgs->GetUTF8String(0, table);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t lastInsertedId = aArgs->AsInt64(1);
+
+  MOZ_ASSERT(table.EqualsLiteral("moz_places") ||
+             table.EqualsLiteral("moz_historyvisits") ||
+             table.EqualsLiteral("moz_bookmarks") ||
+             table.EqualsLiteral("moz_icons"));
+
+  if (table.EqualsLiteral("moz_bookmarks")) {
+    nsNavBookmarks::StoreLastInsertedId(table, lastInsertedId);
+  } else if (table.EqualsLiteral("moz_icons")) {
+    nsFaviconService::StoreLastInsertedId(table, lastInsertedId);
+  } else {
+    nsNavHistory::StoreLastInsertedId(table, lastInsertedId);
+  }
+
+  RefPtr<nsVariant> result = new nsVariant();
+  rv = result->SetAsInt64(lastInsertedId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get Query Param Function
+
+/* static */
+nsresult GetQueryParamFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<GetQueryParamFunction> function = new GetQueryParamFunction();
+  return aDBConn->CreateFunction("get_query_param"_ns, 2, function);
+}
+
+NS_IMPL_ISUPPORTS(GetQueryParamFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+GetQueryParamFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                      nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  nsDependentCString queryString = getSharedUTF8String(aArguments, 0);
+  nsDependentCString paramName = getSharedUTF8String(aArguments, 1);
+
+  RefPtr<nsVariant> result = new nsVariant();
+  if (!queryString.IsEmpty() && !paramName.IsEmpty()) {
+    URLParams::Parse(
+        queryString,
+        [&paramName, &result](const nsAString& aName, const nsAString& aValue) {
+          NS_ConvertUTF16toUTF8 name(aName);
+          if (!paramName.Equals(name)) {
+            return true;
+          }
+          result->SetAsAString(aValue);
+          return false;
+        });
+  }
+
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Hash Function
+
+/* static */
+nsresult HashFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<HashFunction> function = new HashFunction();
+  return aDBConn->CreateFunction("hash"_ns, -1, function);
+}
+
+NS_IMPL_ISUPPORTS(HashFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+HashFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                             nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  // Fetch arguments.  Use default values if they were omitted.
+  uint32_t numEntries;
+  nsresult rv = aArguments->GetNumEntries(&numEntries);
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(numEntries >= 1 && numEntries <= 2, NS_ERROR_FAILURE);
+
+  nsDependentCString str = getSharedUTF8String(aArguments, 0);
+  nsAutoCString mode;
+  if (numEntries > 1) {
+    aArguments->GetUTF8String(1, mode);
+  }
+
+  RefPtr<nsVariant> result = new nsVariant();
+  uint64_t hash;
+  rv = mozilla::places::HashURL(str, mode, &hash);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = result->SetAsInt64((int64_t)hash);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// MD5 Function
+
+/* static */
+nsresult MD5HexFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<MD5HexFunction> function = new MD5HexFunction();
+  return aDBConn->CreateFunction("md5hex"_ns, -1, function);
+}
+
+NS_IMPL_ISUPPORTS(MD5HexFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+MD5HexFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                               nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+
+  // Fetch arguments.
+  uint32_t numEntries;
+  nsresult rv = aArguments->GetNumEntries(&numEntries);
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(numEntries == 1, NS_ERROR_FAILURE);
+  nsDependentCString str = getSharedUTF8String(aArguments, 0);
+
+  nsCOMPtr<nsICryptoHash> hasher =
+      do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // MD5 is not a secure hash function, but it's ok for this use.
+  rv = hasher->Init(nsICryptoHash::MD5);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = hasher->Update(reinterpret_cast<const uint8_t*>(str.BeginReading()),
+                      str.Length());
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString binaryHash, hashString;
+  rv = hasher->Finish(false, binaryHash);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Convert to HEX.
+  static const char* const hex = "0123456789abcdef";
+  hashString.SetCapacity(2 * binaryHash.Length());
+  for (size_t i = 0; i < binaryHash.Length(); ++i) {
+    auto c = static_cast<unsigned char>(binaryHash[i]);
+    hashString.Append(hex[(c >> 4) & 0x0F]);
+    hashString.Append(hex[c & 0x0F]);
+  }
+
+  RefPtr<nsVariant> result = new nsVariant();
+  result->SetAsACString(hashString);
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get prefix function
+
+/* static */
+nsresult GetPrefixFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<GetPrefixFunction> function = new GetPrefixFunction();
+  nsresult rv = aDBConn->CreateFunction("get_prefix"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(GetPrefixFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+GetPrefixFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                  nsIVariant** _result) {
+  MOZ_ASSERT(aArgs);
+
+  uint32_t numArgs;
+  nsresult rv = aArgs->GetNumEntries(&numArgs);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numArgs == 1);
+
+  nsDependentCString spec(getSharedUTF8String(aArgs, 0));
+
+  RefPtr<nsVariant> result = new nsVariant();
+  result->SetAsACString(Substring(spec, 0, getPrefixLength(spec)));
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get host and port function
+
+/* static */
+nsresult GetHostAndPortFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<GetHostAndPortFunction> function = new GetHostAndPortFunction();
+  nsresult rv = aDBConn->CreateFunction("get_host_and_port"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(GetHostAndPortFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+GetHostAndPortFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                       nsIVariant** _result) {
+  MOZ_ASSERT(aArgs);
+
+  uint32_t numArgs;
+  nsresult rv = aArgs->GetNumEntries(&numArgs);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numArgs == 1);
+
+  nsDependentCString spec(getSharedUTF8String(aArgs, 0));
+
+  RefPtr<nsVariant> result = new nsVariant();
+
+  size_type length;
+  size_type index = indexOfHostAndPort(spec, &length);
+  result->SetAsACString(Substring(spec, index, length));
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Strip prefix and userinfo function
+
+/* static */
+nsresult StripPrefixAndUserinfoFunction::create(
+    mozIStorageConnection* aDBConn) {
+  RefPtr<StripPrefixAndUserinfoFunction> function =
+      new StripPrefixAndUserinfoFunction();
+  nsresult rv =
+      aDBConn->CreateFunction("strip_prefix_and_userinfo"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(StripPrefixAndUserinfoFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+StripPrefixAndUserinfoFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                               nsIVariant** _result) {
+  MOZ_ASSERT(aArgs);
+
+  uint32_t numArgs;
+  nsresult rv = aArgs->GetNumEntries(&numArgs);
+  NS_ENSURE_SUCCESS(rv, rv);
+  MOZ_ASSERT(numArgs == 1);
+
+  nsDependentCString spec(getSharedUTF8String(aArgs, 0));
+
+  RefPtr<nsVariant> result = new nsVariant();
+
+  size_type index = indexOfHostAndPort(spec, nullptr);
+  result->SetAsACString(Substring(spec, index, spec.Length() - index));
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Is frecency decaying function
+
+/* static */
+nsresult IsFrecencyDecayingFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<IsFrecencyDecayingFunction> function =
+      new IsFrecencyDecayingFunction();
+  nsresult rv = aDBConn->CreateFunction("is_frecency_decaying"_ns, 0, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(IsFrecencyDecayingFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+IsFrecencyDecayingFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                           nsIVariant** _result) {
+  MOZ_ASSERT(aArgs);
+
+#ifdef DEBUG
+  uint32_t numArgs;
+  MOZ_ASSERT(NS_SUCCEEDED(aArgs->GetNumEntries(&numArgs)) && numArgs == 0);
+#endif
+
+  RefPtr<nsVariant> result = new nsVariant();
+  nsresult rv = result->SetAsBool(nsNavHistory::sIsFrecencyDecaying);
+  NS_ENSURE_SUCCESS(rv, rv);
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Should start frecency recalculation function
+
+/* static */
+nsresult SetShouldStartFrecencyRecalculationFunction::create(
+    mozIStorageConnection* aDBConn) {
+  RefPtr<SetShouldStartFrecencyRecalculationFunction> function =
+      new SetShouldStartFrecencyRecalculationFunction();
+  nsresult rv = aDBConn->CreateFunction(
+      "set_should_start_frecency_recalculation"_ns, 0, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(SetShouldStartFrecencyRecalculationFunction,
+                  mozIStorageFunction)
+
+NS_IMETHODIMP
+SetShouldStartFrecencyRecalculationFunction::OnFunctionCall(
+    mozIStorageValueArray* aArgs, nsIVariant** _result) {
+  MOZ_ASSERT(aArgs);
+
+#ifdef DEBUG
+  uint32_t numArgs;
+  MOZ_ASSERT(NS_SUCCEEDED(aArgs->GetNumEntries(&numArgs)) && numArgs == 0);
+#endif
+
+  // When changing from false to true, dispatch a runnable to the main-thread
+  // to start a recalculation. Once there's nothing left to recalculathe this
+  // boolean will be set back to false. Note this means there will be a short
+  // interval between completing a recalculation and setting this back to false
+  // where we could potentially lose a recalculation request. That should not be
+  // a big deal, since the recalculation will just happen at the next operation
+  // changing frecency or, in the worst case, at the next session.
+  if (!nsNavHistory::sShouldStartFrecencyRecalculation.exchange(true)) {
+    mozilla::Unused << NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "SetShouldStartFrecencyRecalculationFunction::Notify", [] {
+          nsCOMPtr<nsIObserverService> os = services::GetObserverService();
+          if (os) {
+            mozilla::Unused << os->NotifyObservers(
+                nullptr, "frecency-recalculation-needed", nullptr);
+          }
+        }));
+  }
+
+  RefPtr<nsVariant> result = new nsVariant();
+  nsresult rv = result->SetAsBool(true);
+  NS_ENSURE_SUCCESS(rv, rv);
+  result.forget(_result);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Note Sync Change Function
+
+/* static */
+nsresult NoteSyncChangeFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<NoteSyncChangeFunction> function = new NoteSyncChangeFunction();
+  nsresult rv = aDBConn->CreateFunction("note_sync_change"_ns, 0, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(NoteSyncChangeFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+NoteSyncChangeFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                       nsIVariant** _result) {
+  nsNavBookmarks::NoteSyncChange();
+  *_result = nullptr;
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Invalidate days of history Function
+
+/* static */
+nsresult InvalidateDaysOfHistoryFunction::create(
+    mozIStorageConnection* aDBConn) {
+  RefPtr<InvalidateDaysOfHistoryFunction> function =
+      new InvalidateDaysOfHistoryFunction();
+  nsresult rv =
+      aDBConn->CreateFunction("invalidate_days_of_history"_ns, 0, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(InvalidateDaysOfHistoryFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+InvalidateDaysOfHistoryFunction::OnFunctionCall(mozIStorageValueArray* aArgs,
+                                                nsIVariant** _result) {
+  nsNavHistory::InvalidateDaysOfHistory();
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Target folder guid from places query Function
+
+/* static */
+nsresult TargetFolderGuidFunction::create(mozIStorageConnection* aDBConn) {
+  RefPtr<TargetFolderGuidFunction> function = new TargetFolderGuidFunction();
+  nsresult rv = aDBConn->CreateFunction("target_folder_guid"_ns, 1, function);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(TargetFolderGuidFunction, mozIStorageFunction)
+
+NS_IMETHODIMP
+TargetFolderGuidFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                         nsIVariant** _result) {
+  // Must have non-null function arguments.
+  MOZ_ASSERT(aArguments);
+  // Must have one argument.
+  DebugOnly<uint32_t> numArgs = 0;
+  MOZ_ASSERT(NS_SUCCEEDED(aArguments->GetNumEntries(&numArgs)) && numArgs == 1,
+             "unexpected number of arguments");
+
+  nsDependentCString queryURI = getSharedUTF8String(aArguments, 0);
+  Maybe<nsCString> targetFolderGuid =
+      nsNavHistory::GetTargetFolderGuid(queryURI);
+
+  if (targetFolderGuid.isSome()) {
+    RefPtr<nsVariant> result = new nsVariant();
+    result->SetAsACString(*targetFolderGuid);
+    result.forget(_result);
+  } else {
+    *_result = MakeAndAddRef<NullVariant>().take();
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::places
diff --git a/toolkit/components/places/SQLFunctions.h b/toolkit/components/places/SQLFunctions.h
new file mode 100644
index 0000000000..0b0dbca970
--- /dev/null
+++ b/toolkit/components/places/SQLFunctions.h
@@ -0,0 +1,686 @@
+/* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_SQLFunctions_h_
+#define mozilla_places_SQLFunctions_h_
+
+/**
+ * This file contains functions that Places adds to the database handle that can
+ * be accessed by SQL queries.
+ *
+ * Keep the GUID-related parts of this file in sync with
+ * toolkit/downloads/SQLFunctions.[h|cpp]!
+ */
+
+#include "mozIStorageFunction.h"
+#include "mozilla/Attributes.h"
+
+class mozIStorageConnection;
+
+namespace mozilla {
+namespace places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// AutoComplete Matching Function
+
+/**
+ * This function is used to determine if a given set of data should match an
+ * AutoComplete query.
+ *
+ * In SQL, you'd use it in the WHERE clause like so:
+ * WHERE AUTOCOMPLETE_MATCH(aSearchString, aURL, aTitle, aTags, aVisitCount,
+ *                          aTyped, aBookmark, aOpenPageCount, aMatchBehavior,
+ *                          aSearchBehavior, aFallbackTitle)
+ *
+ * @param aSearchString
+ *        The string to compare against.
+ * @param aURL
+ *        The URL to test for an AutoComplete match.
+ * @param aTitle
+ *        The title to test for an AutoComplete match.
+ * @param aTags
+ *        The tags to test for an AutoComplete match.
+ * @param aVisitCount
+ *        The number of visits aURL has.
+ * @param aTyped
+ *        Indicates if aURL is a typed URL or not.  Treated as a boolean.
+ * @param aBookmark
+ *        Indicates if aURL is a bookmark or not.  Treated as a boolean.
+ * @param aOpenPageCount
+ *        The number of times aURL has been registered as being open.  (See
+ *        UrlbarProviderOpenTabs::registerOpenTab.)
+ * @param aMatchBehavior
+ *        The match behavior to use for this search.
+ * @param aSearchBehavior
+ *        A bitfield dictating the search behavior.
+ * @param aFallbackTitle
+ *        The title may come from a bookmark or a snapshot, in that case the
+ *        caller can provide the original history title to match on both.
+ */
+class MatchAutoCompleteFunction final : public mozIStorageFunction {
+ public:
+  MatchAutoCompleteFunction();
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~MatchAutoCompleteFunction() = default;
+
+  /**
+   * IntegerVariants for 0 and 1 are frequently used in awesomebar queries,
+   * so we cache them to avoid allocating memory repeatedly.
+   */
+  nsCOMPtr<nsIVariant> mCachedZero;
+  nsCOMPtr<nsIVariant> mCachedOne;
+
+  /**
+   * Argument Indexes
+   */
+  static const uint32_t kArgSearchString = 0;
+  static const uint32_t kArgIndexURL = 1;
+  static const uint32_t kArgIndexTitle = 2;
+  static const uint32_t kArgIndexTags = 3;
+  static const uint32_t kArgIndexVisitCount = 4;
+  static const uint32_t kArgIndexTyped = 5;
+  static const uint32_t kArgIndexBookmark = 6;
+  static const uint32_t kArgIndexOpenPageCount = 7;
+  static const uint32_t kArgIndexMatchBehavior = 8;
+  static const uint32_t kArgIndexSearchBehavior = 9;
+  static const uint32_t kArgIndexFallbackTitle = 10;
+  static const uint32_t kArgIndexLength = 11;
+
+  /**
+   * Typedefs
+   */
+  typedef bool (*searchFunctionPtr)(const nsDependentCSubstring& aToken,
+                                    const nsACString& aSourceString);
+
+  typedef nsACString::const_char_iterator const_char_iterator;
+
+  /**
+   * Obtains the search function to match on.
+   *
+   * @param aBehavior
+   *        The matching behavior to use defined by one of the
+   *        mozIPlacesAutoComplete::MATCH_* values.
+   * @return a pointer to the function that will perform the proper search.
+   */
+  static searchFunctionPtr getSearchFunction(int32_t aBehavior);
+
+  /**
+   * Tests if aSourceString starts with aToken.
+   *
+   * @param aToken
+   *        The string to search for.
+   * @param aSourceString
+   *        The string to search.
+   * @return true if found, false otherwise.
+   */
+  static bool findBeginning(const nsDependentCSubstring& aToken,
+                            const nsACString& aSourceString);
+
+  /**
+   * Tests if aSourceString starts with aToken in a case sensitive way.
+   *
+   * @param aToken
+   *        The string to search for.
+   * @param aSourceString
+   *        The string to search.
+   * @return true if found, false otherwise.
+   */
+  static bool findBeginningCaseSensitive(const nsDependentCSubstring& aToken,
+                                         const nsACString& aSourceString);
+
+  /**
+   * Searches aSourceString for aToken anywhere in the string in a case-
+   * insensitive way.
+   *
+   * @param aToken
+   *        The string to search for.
+   * @param aSourceString
+   *        The string to search.
+   * @return true if found, false otherwise.
+   */
+  static bool findAnywhere(const nsDependentCSubstring& aToken,
+                           const nsACString& aSourceString);
+
+  /**
+   * Tests if aToken is found on a word boundary in aSourceString.
+   *
+   * @param aToken
+   *        The string to search for.
+   * @param aSourceString
+   *        The string to search.
+   * @return true if found, false otherwise.
+   */
+  static bool findOnBoundary(const nsDependentCSubstring& aToken,
+                             const nsACString& aSourceString);
+
+  /**
+   * Fixes a URI's spec such that it is ready to be searched.  This includes
+   * unescaping escaped characters and removing certain specs that we do not
+   * care to search for.
+   *
+   * @param aURISpec
+   *        The spec of the URI to prepare for searching.
+   * @param aMatchBehavior
+   *        The matching behavior to use defined by one of the
+   *        mozIPlacesAutoComplete::MATCH_* values.
+   * @param aSpecBuf
+   *        A string buffer that the returned slice can point into, if needed.
+   * @return the fixed up string.
+   */
+  static nsDependentCSubstring fixupURISpec(const nsACString& aURISpec,
+                                            int32_t aMatchBehavior,
+                                            nsACString& aSpecBuf);
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Frecency Calculation Function
+
+/**
+ * This function is used to calculate frecency for a page.
+ *
+ * In SQL, you'd use it in when setting frecency like:
+ * SET frecency = CALCULATE_FRECENCY(place_id).
+ * Optional parameters must be passed in if the page is not yet in the database,
+ * otherwise they will be fetched from it automatically.
+ *
+ * @param {int64_t} pageId
+ *        The id of the page.  Pass -1 if the page is being added right now.
+ * @param [optional] {int32_t} useRedirectBonus
+ *        Whether we should use the lower redirect bonus for the most recent
+ *        page visit.  If not passed in, it will use a database guess.
+ */
+class CalculateFrecencyFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~CalculateFrecencyFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Alternative Frecency Calculation Function
+
+/**
+ * This function is used to calculate alternative frecency for a page.
+ *
+ * In SQL, you'd use it in when setting frecency like:
+ * SET alt_frecency = CALCULATE_ALT_FRECENCY(place_id).
+ * Optional parameters must be passed in if the page is not yet in the database,
+ * otherwise they will be fetched from it automatically.
+ *
+ * @param {int64_t} pageId
+ *        The id of the page.  Pass -1 if the page is being added right now.
+ * @param {int32_t} [useRedirectBonus]
+ *        Whether we should use the lower redirect bonus for the most recent
+ *        page visit.  If not passed in, it will use a database guess.
+ */
+class CalculateAltFrecencyFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~CalculateAltFrecencyFunction() = default;
+};
+
+/**
+ * SQL function to generate a GUID for a place or bookmark item.  This is just
+ * a wrapper around GenerateGUID in Helpers.h.
+ *
+ * @return a guid for the item.
+ */
+class GenerateGUIDFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~GenerateGUIDFunction() = default;
+};
+
+/**
+ * SQL function to check if a GUID is valid.  This is just a wrapper around
+ * IsValidGUID in Helpers.h.
+ *
+ * @return true if valid, false otherwise.
+ */
+class IsValidGUIDFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~IsValidGUIDFunction() = default;
+};
+
+/**
+ * SQL function to unreverse the rev_host of a page.
+ *
+ * @param rev_host
+ *        The rev_host value of the page.
+ *
+ * @return the unreversed host of the page.
+ */
+class GetUnreversedHostFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~GetUnreversedHostFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Fixup URL Function
+
+/**
+ * Make a given URL more suitable for searches, by removing common prefixes
+ * such as "www."
+ *
+ * @param url
+ *        A URL.
+ * @return
+ *        The same URL, with redundant parts removed.
+ */
+class FixupURLFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~FixupURLFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Store Last Inserted Id Function
+
+/**
+ * Store the last inserted id for reference purpose.
+ *
+ * @param tableName
+ *        The table name.
+ * @param id
+ *        The last inserted id.
+ * @return null
+ */
+class StoreLastInsertedIdFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~StoreLastInsertedIdFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Hash Function
+
+/**
+ * Calculates hash for a given string using the mfbt AddToHash function.
+ *
+ * @param string
+ *        A string.
+ * @return
+ *        The hash for the string.
+ */
+class HashFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~HashFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// MD5 Function
+
+/**
+ * Calculates md5 hash for a given string.
+ *
+ * @param string
+ *        A string.
+ * @return
+ *        The hash for the string.
+ */
+class MD5HexFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~MD5HexFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get Query Param Function
+
+/**
+ * Extracts and returns the value of a parameter from a query string.
+ *
+ * @param string
+ *        A string.
+ * @return
+ *        The value of the query parameter as a string, or NULL if not set.
+ */
+class GetQueryParamFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~GetQueryParamFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get prefix function
+
+/**
+ * Gets the length of the prefix in a URL.  "Prefix" is defined to be the
+ * scheme, colon, and, if present, two slashes.
+ *
+ * @param url
+ *        A URL, or a string that may be a URL.
+ * @return
+ *        If `url` is actually a URL and has a prefix, then this returns the
+ *        prefix.  Otherwise this returns an empty string.
+ */
+class GetPrefixFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~GetPrefixFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Get host and port function
+
+/**
+ * Gets the host and port substring of a URL.
+ *
+ * @param url
+ *        A URL, or a string that may be a URL.
+ * @return
+ *        If `url` is actually a URL, or if it's a URL without the prefix, then
+ *        this returns the host and port substring of the URL.  Otherwise, this
+ *        returns `url` itself.
+ */
+class GetHostAndPortFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~GetHostAndPortFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Strip prefix function
+
+/**
+ * Gets the part of a URL after its prefix and userinfo; i.e., the substring
+ * starting at the host.
+ *
+ * @param url
+ *        A URL, or a string that may be a URL.
+ * @return
+ *        If `url` is actually a URL, or if it's a URL without the prefix, then
+ *        this returns the substring starting at the host.  Otherwise, this
+ *        returns `url` itself.
+ */
+class StripPrefixAndUserinfoFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~StripPrefixAndUserinfoFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Is frecency decaying function
+
+/**
+ * Returns nsNavHistory::IsFrecencyDecaying().
+ *
+ * @return
+ *        True if frecency is currently decaying and false otherwise.
+ */
+class IsFrecencyDecayingFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~IsFrecencyDecayingFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Should start frecency recalculation function
+
+/**
+ * sets nsNavHistory::sShouldStartFrecencyRecalculation to true.
+ * @returns {boolean} true
+ */
+class SetShouldStartFrecencyRecalculationFunction final
+    : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~SetShouldStartFrecencyRecalculationFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Note Sync Change Function
+
+/**
+ * Bumps the global Sync change counter. See the comment above
+ * `totalSyncChanges` in `nsINavBookmarksService` for a more detailed
+ * explanation.
+ */
+class NoteSyncChangeFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~NoteSyncChangeFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Invalidate days of history Function
+
+/**
+ * Invalidate the days of history in nsNavHistory.
+ */
+class InvalidateDaysOfHistoryFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~InvalidateDaysOfHistoryFunction() = default;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// Target folder guid from places query Function
+
+/**
+ * Target folder guid from places query.
+ */
+class TargetFolderGuidFunction final : public mozIStorageFunction {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_MOZISTORAGEFUNCTION
+
+  /**
+   * Registers the function with the specified database connection.
+   *
+   * @param aDBConn
+   *        The database connection to register with.
+   */
+  static nsresult create(mozIStorageConnection* aDBConn);
+
+ private:
+  ~TargetFolderGuidFunction() = default;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_SQLFunctions_h_
diff --git a/toolkit/components/places/Shutdown.cpp b/toolkit/components/places/Shutdown.cpp
new file mode 100644
index 0000000000..8327784b86
--- /dev/null
+++ b/toolkit/components/places/Shutdown.cpp
@@ -0,0 +1,217 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Shutdown.h"
+#include "mozilla/Unused.h"
+#include "mozilla/Services.h"
+#include "mozilla/SimpleEnumerator.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIProperty.h"
+#include "nsIObserverService.h"
+#include "nsIWritablePropertyBag.h"
+#include "nsVariant.h"
+#include "Database.h"
+
+namespace mozilla {
+namespace places {
+
+uint16_t PlacesShutdownBlocker::sCounter = 0;
+Atomic<bool> PlacesShutdownBlocker::sIsStarted(false);
+
+PlacesShutdownBlocker::PlacesShutdownBlocker(const nsString& aName)
+    : mName(aName), mState(NOT_STARTED), mCounter(sCounter++) {
+  MOZ_ASSERT(NS_IsMainThread());
+  // During tests, we can end up with the Database singleton being resurrected.
+  // Make sure that each instance of DatabaseShutdown has a unique name.
+  if (mCounter > 1) {
+    mName.AppendInt(mCounter);
+  }
+  // Create a barrier that will be exposed to clients through GetClient(), so
+  // they can block Places shutdown.
+  nsCOMPtr<nsIAsyncShutdownService> asyncShutdown =
+      services::GetAsyncShutdownService();
+  MOZ_ASSERT(asyncShutdown);
+  if (asyncShutdown) {
+    nsCOMPtr<nsIAsyncShutdownBarrier> barrier;
+    nsresult rv = asyncShutdown->MakeBarrier(mName, getter_AddRefs(barrier));
+    MOZ_ALWAYS_SUCCEEDS(rv);
+    if (NS_SUCCEEDED(rv) && barrier) {
+      mBarrier = new nsMainThreadPtrHolder<nsIAsyncShutdownBarrier>(
+          "PlacesShutdownBlocker::mBarrier", barrier);
+    }
+  }
+}
+
+// nsIAsyncShutdownBlocker
+NS_IMETHODIMP
+PlacesShutdownBlocker::GetName(nsAString& aName) {
+  aName = mName;
+  return NS_OK;
+}
+
+// nsIAsyncShutdownBlocker
+NS_IMETHODIMP
+PlacesShutdownBlocker::GetState(nsIPropertyBag** _state) {
+  NS_ENSURE_ARG_POINTER(_state);
+
+  nsCOMPtr<nsIWritablePropertyBag> bag =
+      do_CreateInstance("@mozilla.org/hash-property-bag;1");
+  NS_ENSURE_TRUE(bag, NS_ERROR_OUT_OF_MEMORY);
+
+  RefPtr<nsVariant> progress = new nsVariant();
+  Unused << NS_WARN_IF(NS_FAILED(progress->SetAsUint8(mState)));
+  Unused << NS_WARN_IF(
+      NS_FAILED(bag->SetProperty(u"PlacesShutdownProgress"_ns, progress)));
+
+  if (mBarrier) {
+    nsCOMPtr<nsIPropertyBag> barrierState;
+    if (NS_SUCCEEDED(mBarrier->GetState(getter_AddRefs(barrierState))) &&
+        barrierState) {
+      nsCOMPtr<nsISimpleEnumerator> enumerator;
+      if (NS_SUCCEEDED(
+              barrierState->GetEnumerator(getter_AddRefs(enumerator))) &&
+          enumerator) {
+        for (const auto& property : SimpleEnumerator<nsIProperty>(enumerator)) {
+          nsAutoString prefix(u"Barrier: "_ns);
+          nsAutoString name;
+          Unused << NS_WARN_IF(NS_FAILED(property->GetName(name)));
+          prefix.Append(name);
+          nsCOMPtr<nsIVariant> value;
+          Unused << NS_WARN_IF(
+              NS_FAILED(property->GetValue(getter_AddRefs(value))));
+          Unused << NS_WARN_IF(NS_FAILED(bag->SetProperty(prefix, value)));
+        }
+      }
+    }
+  }
+  bag.forget(_state);
+  return NS_OK;
+}
+
+already_AddRefed<nsIAsyncShutdownClient> PlacesShutdownBlocker::GetClient() {
+  nsCOMPtr<nsIAsyncShutdownClient> client;
+  if (mBarrier) {
+    MOZ_ALWAYS_SUCCEEDS(mBarrier->GetClient(getter_AddRefs(client)));
+  }
+  return client.forget();
+}
+
+// nsIAsyncShutdownBlocker
+NS_IMETHODIMP
+PlacesShutdownBlocker::BlockShutdown(nsIAsyncShutdownClient* aParentClient) {
+  MOZ_ASSERT(NS_IsMainThread());
+  mParentClient = new nsMainThreadPtrHolder<nsIAsyncShutdownClient>(
+      "ClientsShutdownBlocker::mParentClient", aParentClient);
+  mState = RECEIVED_BLOCK_SHUTDOWN;
+
+  if (NS_WARN_IF(!mBarrier)) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Wait until all the clients have removed their blockers.
+  MOZ_ALWAYS_SUCCEEDS(mBarrier->Wait(this));
+
+  mState = CALLED_WAIT_CLIENTS;
+  return NS_OK;
+}
+
+// nsIAsyncShutdownCompletionCallback
+NS_IMETHODIMP
+PlacesShutdownBlocker::Done() {
+  MOZ_ASSERT(false, "Should always be overridden");
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(PlacesShutdownBlocker, nsIAsyncShutdownBlocker,
+                  nsIAsyncShutdownCompletionCallback)
+
+////////////////////////////////////////////////////////////////////////////////
+
+ClientsShutdownBlocker::ClientsShutdownBlocker()
+    : PlacesShutdownBlocker(u"Places Clients shutdown"_ns) {
+  // Do nothing.
+}
+
+// nsIAsyncShutdownCompletionCallback
+NS_IMETHODIMP
+ClientsShutdownBlocker::Done() {
+  // At this point all the clients are done, we can stop blocking the shutdown
+  // phase.
+  mState = RECEIVED_DONE;
+
+  // mParentClient is nullptr in tests.
+  if (mParentClient) {
+    nsresult rv = mParentClient->RemoveBlocker(this);
+    if (NS_WARN_IF(NS_FAILED(rv))) return rv;
+    mParentClient = nullptr;
+  }
+  mBarrier = nullptr;
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+ConnectionShutdownBlocker::ConnectionShutdownBlocker(Database* aDatabase)
+    : PlacesShutdownBlocker(u"Places Connection shutdown"_ns),
+      mDatabase(aDatabase) {
+  // Do nothing.
+}
+
+// nsIAsyncShutdownCompletionCallback
+NS_IMETHODIMP
+ConnectionShutdownBlocker::Done() {
+  // At this point all the clients are done, we can stop blocking the shutdown
+  // phase.
+  mState = RECEIVED_DONE;
+
+  // Annotate that Database shutdown started.
+  sIsStarted = true;
+
+  // At this stage, any use of this database is forbidden. Get rid of
+  // `gDatabase`. Note, however, that the database could be
+  // resurrected.  This can happen in particular during tests.
+  MOZ_ASSERT(Database::gDatabase == nullptr ||
+             Database::gDatabase == mDatabase);
+  Database::gDatabase = nullptr;
+
+  // Database::Shutdown will invoke Complete once the connection is closed.
+  mDatabase->Shutdown();
+  mState = CALLED_STORAGESHUTDOWN;
+  mBarrier = nullptr;
+  return NS_OK;
+}
+
+// mozIStorageCompletionCallback
+NS_IMETHODIMP
+ConnectionShutdownBlocker::Complete(nsresult, nsISupports*) {
+  MOZ_ASSERT(NS_IsMainThread());
+  mState = RECEIVED_STORAGESHUTDOWN_COMPLETE;
+
+  // The connection is closed, the Database has no more use, so we can break
+  // possible cycles.
+  mDatabase = nullptr;
+
+  // Notify the connection has gone.
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  MOZ_ASSERT(os);
+  if (os) {
+    MOZ_ALWAYS_SUCCEEDS(
+        os->NotifyObservers(nullptr, TOPIC_PLACES_CONNECTION_CLOSED, nullptr));
+  }
+  mState = NOTIFIED_OBSERVERS_PLACES_CONNECTION_CLOSED;
+
+  // mParentClient is nullptr in tests
+  if (mParentClient) {
+    nsresult rv = mParentClient->RemoveBlocker(this);
+    if (NS_WARN_IF(NS_FAILED(rv))) return rv;
+    mParentClient = nullptr;
+  }
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(ConnectionShutdownBlocker, PlacesShutdownBlocker,
+                            mozIStorageCompletionCallback)
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/Shutdown.h b/toolkit/components/places/Shutdown.h
new file mode 100644
index 0000000000..3e5612a454
--- /dev/null
+++ b/toolkit/components/places/Shutdown.h
@@ -0,0 +1,155 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_Shutdown_h_
+#define mozilla_places_Shutdown_h_
+
+#include "mozIStorageCompletionCallback.h"
+#include "nsIAsyncShutdown.h"
+#include "nsProxyRelease.h"
+
+namespace mozilla {
+namespace places {
+
+class Database;
+
+/**
+ * This is most of the code responsible for Places shutdown.
+ *
+ * PHASE 1 (Legacy clients shutdown)
+ * The shutdown procedure begins when the Database singleton receives
+ * profile-change-teardown (note that tests will instead notify nsNavHistory,
+ * that forwards the notification to the Database instance).
+ * Database::Observe first of all checks if initialization was completed
+ * properly, to avoid race conditions, then it notifies "places-shutdown" to
+ * legacy clients. Legacy clients are supposed to start and complete any
+ * shutdown critical work in the same tick, since we won't wait for them.
+
+ * PHASE 2 (Modern clients shutdown)
+ * Modern clients should instead register as a blocker by passing a promise to
+ * nsINavHistoryService::shutdownClient (for example see Sanitizer.jsm), so they
+ * block Places shutdown until the promise is resolved.
+ * When profile-change-teardown is observed by async shutdown, it calls
+ * ClientsShutdownBlocker::BlockShutdown. This class is registered as a teardown
+ * phase blocker in Database::Init (see Database::mClientsShutdown).
+ * ClientsShutdownBlocker::BlockShudown waits for all the clients registered
+ * through nsINavHistoryService::shutdownClient. When all the clients are done,
+ * its `Done` method is invoked, and it stops blocking the shutdown phase, so
+ * that it can continue.
+ *
+ * PHASE 3 (Connection shutdown)
+ * ConnectionBlocker is registered as a profile-before-change blocker in
+ * Database::Init (see Database::mConnectionShutdown).
+ * When profile-before-change is observer by async shutdown, it calls
+ * ConnectionShutdownBlocker::BlockShutdown.
+ * Then the control is passed to Database::Shutdown, that executes some sanity
+ * checks, clears cached statements and proceeds with asyncClose.
+ * Once the connection is definitely closed, Database will call back
+ * ConnectionBlocker::Complete. At this point a final
+ * places-connection-closed notification is sent, for testing purposes.
+ */
+
+/**
+ * A base AsyncShutdown blocker in charge of shutting down Places.
+ */
+class PlacesShutdownBlocker : public nsIAsyncShutdownBlocker,
+                              public nsIAsyncShutdownCompletionCallback {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIASYNCSHUTDOWNBLOCKER
+  NS_DECL_NSIASYNCSHUTDOWNCOMPLETIONCALLBACK
+
+  explicit PlacesShutdownBlocker(const nsString& aName);
+
+  already_AddRefed<nsIAsyncShutdownClient> GetClient();
+
+  // The current state, used internally and for forensics/debugging purposes.
+  // Not all the states make sense for all the derived classes.
+  enum States {
+    NOT_STARTED,
+    // Execution of `BlockShutdown` in progress.
+    RECEIVED_BLOCK_SHUTDOWN,
+
+    // Values specific to ClientsShutdownBlocker
+    // a. Set while we are waiting for clients to do their job and unblock us.
+    CALLED_WAIT_CLIENTS,
+    // b. Set when all the clients are done.
+    RECEIVED_DONE,
+
+    // Values specific to ConnectionShutdownBlocker
+    // a. Set after we notified observers that Places is closing the connection.
+    NOTIFIED_OBSERVERS_PLACES_WILL_CLOSE_CONNECTION,
+    // b. Set after we pass control to Database::Shutdown, and wait for it to
+    // close the connection and call our `Complete` method when done.
+    CALLED_STORAGESHUTDOWN,
+    // c. Set when Database has closed the connection and passed control to
+    // us through `Complete`.
+    RECEIVED_STORAGESHUTDOWN_COMPLETE,
+    // d. We have notified observers that Places has closed the connection.
+    NOTIFIED_OBSERVERS_PLACES_CONNECTION_CLOSED,
+  };
+  States State() { return mState; }
+
+  static Atomic<bool> sIsStarted;
+
+ protected:
+  // The blocker name, also used as barrier name.
+  nsString mName;
+  // The current state, see States.
+  States mState;
+  // The barrier optionally used to wait for clients.
+  nsMainThreadPtrHandle<nsIAsyncShutdownBarrier> mBarrier;
+  // The parent object who registered this as a blocker.
+  nsMainThreadPtrHandle<nsIAsyncShutdownClient> mParentClient;
+
+  // As tests may resurrect a dead `Database`, we use a counter to
+  // give the instances of `PlacesShutdownBlocker` unique names.
+  uint16_t mCounter;
+  static uint16_t sCounter;
+
+  virtual ~PlacesShutdownBlocker() = default;
+};
+
+/**
+ * Blocker also used to wait for clients, through an owned barrier.
+ */
+class ClientsShutdownBlocker final : public PlacesShutdownBlocker {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(ClientsShutdownBlocker,
+                                       PlacesShutdownBlocker)
+
+  explicit ClientsShutdownBlocker();
+
+  NS_IMETHOD Done() override;
+
+ private:
+  ~ClientsShutdownBlocker() = default;
+};
+
+/**
+ * Blocker used to wait when closing the database connection.
+ */
+class ConnectionShutdownBlocker final : public PlacesShutdownBlocker,
+                                        public mozIStorageCompletionCallback {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_MOZISTORAGECOMPLETIONCALLBACK
+
+  explicit ConnectionShutdownBlocker(mozilla::places::Database* aDatabase);
+
+  NS_IMETHOD Done() override;
+
+ private:
+  ~ConnectionShutdownBlocker() = default;
+
+  // The owning database.
+  // The cycle is broken in method Complete(), once the connection
+  // has been closed by mozStorage.
+  RefPtr<mozilla::places::Database> mDatabase;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_Shutdown_h_
diff --git a/toolkit/components/places/SyncedBookmarksMirror.h b/toolkit/components/places/SyncedBookmarksMirror.h
new file mode 100644
index 0000000000..4839896841
--- /dev/null
+++ b/toolkit/components/places/SyncedBookmarksMirror.h
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_SyncedBookmarksMirror_h_
+#define mozilla_places_SyncedBookmarksMirror_h_
+
+#include "mozISyncedBookmarksMirror.h"
+#include "nsCOMPtr.h"
+
+extern "C" {
+
+// Implemented in Rust, in the `bookmark_sync` crate.
+void NS_NewSyncedBookmarksMerger(mozISyncedBookmarksMerger** aResult);
+
+}  // extern "C"
+
+namespace mozilla {
+namespace places {
+
+already_AddRefed<mozISyncedBookmarksMerger> NewSyncedBookmarksMerger() {
+  nsCOMPtr<mozISyncedBookmarksMerger> merger;
+  NS_NewSyncedBookmarksMerger(getter_AddRefs(merger));
+  return merger.forget();
+}
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_SyncedBookmarksMirror_h_
diff --git a/toolkit/components/places/SyncedBookmarksMirror.sys.mjs b/toolkit/components/places/SyncedBookmarksMirror.sys.mjs
new file mode 100644
index 0000000000..31688928b3
--- /dev/null
+++ b/toolkit/components/places/SyncedBookmarksMirror.sys.mjs
@@ -0,0 +1,2617 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file implements a mirror and two-way merger for synced bookmarks. The
+ * mirror matches the complete tree stored on the Sync server, and stages new
+ * bookmarks changed on the server since the last sync. The merger walks the
+ * local tree in Places and the mirrored remote tree, produces a new merged
+ * tree, then updates the local tree to reflect the merged tree.
+ *
+ * Let's start with an overview of the different classes, and how they fit
+ * together.
+ *
+ * - `SyncedBookmarksMirror` sets up the database, validates and upserts new
+ *   incoming records, attaches to Places, and applies the changed records.
+ *   During application, we fetch the local and remote bookmark trees, merge
+ *   them, and update Places to match. Merging and application happen in a
+ *   single transaction, so applying the merged tree won't collide with local
+ *   changes. A failure at this point aborts the merge and leaves Places
+ *   unchanged.
+ *
+ * - A `BookmarkTree` is a fully rooted tree that also notes deletions. A
+ *   `BookmarkNode` represents a local item in Places, or a remote item in the
+ *   mirror.
+ *
+ * - A `MergedBookmarkNode` holds a local node, a remote node, and a
+ *   `MergeState` that indicates which node to prefer when updating Places and
+ *   the server to match the merged tree.
+ *
+ * - `BookmarkObserverRecorder` records all changes made to Places during the
+ *   merge, then dispatches `PlacesObservers` notifications. Places uses
+ *   these notifications to update the UI and internal caches. We can't dispatch
+ *   during the merge because observers won't see the changes until the merge
+ *   transaction commits and the database is consistent again.
+ *
+ * - After application, we flag all applied incoming items as merged, create
+ *   Sync records for the locally new and updated items in Places, and upload
+ *   the records to the server. At this point, all outgoing items are flagged as
+ *   changed in Places, so the next sync can resume cleanly if the upload is
+ *   interrupted or fails.
+ *
+ * - Once upload succeeds, we update the mirror with the uploaded records, so
+ *   that the mirror matches the server again. An interruption or error here
+ *   will leave the uploaded items flagged as changed in Places, so we'll merge
+ *   them again on the next sync. This is redundant work, but shouldn't cause
+ *   issues.
+ */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Async: "resource://services-common/async.sys.mjs",
+  Log: "resource://gre/modules/Log.sys.mjs",
+  PlacesSyncUtils: "resource://gre/modules/PlacesSyncUtils.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "MirrorLog", () =>
+  lazy.Log.repository.getLogger("Sync.Engine.Bookmarks.Mirror")
+);
+
+const SyncedBookmarksMerger = Components.Constructor(
+  "@mozilla.org/browser/synced-bookmarks-merger;1",
+  "mozISyncedBookmarksMerger"
+);
+
+// These can be removed once they're exposed in a central location (bug
+// 1375896).
+const DB_URL_LENGTH_MAX = 65536;
+const DB_TITLE_LENGTH_MAX = 4096;
+
+// The current mirror database schema version. Bump for migrations, then add
+// migration code to `migrateMirrorSchema`.
+const MIRROR_SCHEMA_VERSION = 9;
+
+// Use a shared jankYielder in these functions
+ChromeUtils.defineLazyGetter(lazy, "yieldState", () => lazy.Async.yieldState());
+
+/** Adapts a `Log.sys.mjs` logger to a `mozIServicesLogSink`. */
+class LogAdapter {
+  constructor(log) {
+    this.log = log;
+  }
+
+  get maxLevel() {
+    let level = this.log.level;
+    if (level <= lazy.Log.Level.All) {
+      return Ci.mozIServicesLogSink.LEVEL_TRACE;
+    }
+    if (level <= lazy.Log.Level.Info) {
+      return Ci.mozIServicesLogSink.LEVEL_DEBUG;
+    }
+    if (level <= lazy.Log.Level.Warn) {
+      return Ci.mozIServicesLogSink.LEVEL_WARN;
+    }
+    if (level <= lazy.Log.Level.Error) {
+      return Ci.mozIServicesLogSink.LEVEL_ERROR;
+    }
+    return Ci.mozIServicesLogSink.LEVEL_OFF;
+  }
+
+  trace(message) {
+    this.log.trace(message);
+  }
+
+  debug(message) {
+    this.log.debug(message);
+  }
+
+  warn(message) {
+    this.log.warn(message);
+  }
+
+  error(message) {
+    this.log.error(message);
+  }
+}
+
+/**
+ * A helper to track the progress of a merge for telemetry and shutdown hang
+ * reporting.
+ */
+class ProgressTracker {
+  constructor(recordStepTelemetry) {
+    this.recordStepTelemetry = recordStepTelemetry;
+    this.steps = [];
+  }
+
+  /**
+   * Records a merge step, updating the shutdown blocker state.
+   *
+   * @param {String} name A step name from `ProgressTracker.STEPS`. This is
+   *        included in shutdown hang crash reports, along with the timestamp
+   *        the step was recorded.
+   * @param {Number} [took] The time taken, in milliseconds.
+   * @param {Array} [counts] An array of additional counts to report in the
+   *        shutdown blocker state.
+   */
+  step(name, took = -1, counts = null) {
+    let info = { step: name, at: Date.now() };
+    if (took > -1) {
+      info.took = took;
+    }
+    if (counts) {
+      info.counts = counts;
+    }
+    this.steps.push(info);
+  }
+
+  /**
+   * Records a merge step with timings and counts for telemetry.
+   *
+   * @param {String} name The step name.
+   * @param {Number} took The time taken, in milliseconds.
+   * @param {Array} [counts] An array of additional `{ name, count }` tuples to
+   *        record in telemetry for this step.
+   */
+  stepWithTelemetry(name, took, counts = null) {
+    this.step(name, took, counts);
+    this.recordStepTelemetry(name, took, counts);
+  }
+
+  /**
+   * Records a merge step with the time taken and item count.
+   *
+   * @param {String} name The step name.
+   * @param {Number} took The time taken, in milliseconds.
+   * @param {Number} count The number of items handled in this step.
+   */
+  stepWithItemCount(name, took, count) {
+    this.stepWithTelemetry(name, took, [{ name: "items", count }]);
+  }
+
+  /**
+   * Clears all recorded merge steps.
+   */
+  reset() {
+    this.steps = [];
+  }
+
+  /**
+   * Returns the shutdown blocker state. This is included in shutdown hang
+   * crash reports, in the `AsyncShutdownTimeout` annotation.
+   *
+   * @see    `fetchState` in `AsyncShutdown` for more details.
+   * @return {Object} A stringifiable object with the recorded steps.
+   */
+  fetchState() {
+    return { steps: this.steps };
+  }
+}
+
+/** Merge steps for which we record progress. */
+ProgressTracker.STEPS = {
+  FETCH_LOCAL_TREE: "fetchLocalTree",
+  FETCH_REMOTE_TREE: "fetchRemoteTree",
+  MERGE: "merge",
+  APPLY: "apply",
+  NOTIFY_OBSERVERS: "notifyObservers",
+  FETCH_LOCAL_CHANGE_RECORDS: "fetchLocalChangeRecords",
+  FINALIZE: "finalize",
+};
+
+/**
+ * A mirror maintains a copy of the complete tree as stored on the Sync server.
+ * It is persistent.
+ *
+ * The mirror schema is a hybrid of how Sync and Places represent bookmarks.
+ * The `items` table contains item attributes (title, kind, URL, etc.), while
+ * the `structure` table stores parent-child relationships and position.
+ * This is similar to how iOS encodes "value" and "structure" state,
+ * though we handle these differently when merging. See `BookmarkMerger` for
+ * details.
+ *
+ * There's no guarantee that the remote state is consistent. We might be missing
+ * parents or children, or a bookmark and its parent might disagree about where
+ * it belongs. This means we need a strategy to handle missing parents and
+ * children.
+ *
+ * We treat the `children` of the last parent we see as canonical, and ignore
+ * the child's `parentid` entirely. We also ignore missing children, and
+ * temporarily reparent bookmarks with missing parents to "unfiled". When we
+ * eventually see the missing items, either during a later sync or as part of
+ * repair, we'll fill in the mirror's gaps and fix up the local tree.
+ *
+ * During merging, we won't intentionally try to fix inconsistencies on the
+ * server, and opt to build as complete a tree as we can from the remote state,
+ * even if we diverge from what's in the mirror. See bug 1433512 for context.
+ *
+ * If a sync is interrupted, we resume downloading from the server collection
+ * last modified time, or the server last modified time of the most recent
+ * record if newer. New incoming records always replace existing records in the
+ * mirror.
+ *
+ * We delete the mirror database on client reset, including when the sync ID
+ * changes on the server, and when the user is node reassigned, disables the
+ * bookmarks engine, or signs out.
+ */
+export class SyncedBookmarksMirror {
+  constructor(
+    db,
+    wasCorrupt = false,
+    {
+      recordStepTelemetry,
+      recordValidationTelemetry,
+      finalizeAt = lazy.PlacesUtils.history.shutdownClient.jsclient,
+    } = {}
+  ) {
+    this.db = db;
+    this.wasCorrupt = wasCorrupt;
+    this.recordValidationTelemetry = recordValidationTelemetry;
+
+    this.merger = new SyncedBookmarksMerger();
+    this.merger.db = db.unsafeRawConnection.QueryInterface(
+      Ci.mozIStorageConnection
+    );
+    this.merger.logger = new LogAdapter(lazy.MirrorLog);
+
+    // Automatically close the database connection on shutdown. `progress`
+    // tracks state for shutdown hang reporting.
+    this.progress = new ProgressTracker(recordStepTelemetry);
+    this.finalizeController = new AbortController();
+    this.finalizeAt = finalizeAt;
+    this.finalizeBound = () => this.finalize({ alsoCleanup: false });
+    this.finalizeAt.addBlocker(
+      "SyncedBookmarksMirror: finalize",
+      this.finalizeBound,
+      { fetchState: () => this.progress }
+    );
+  }
+
+  /**
+   * Sets up the mirror database connection and upgrades the mirror to the
+   * newest schema version. Automatically recreates the mirror if it's corrupt;
+   * throws on failure.
+   *
+   * @param  {String} options.path
+   *         The path to the mirror database file, either absolute or relative
+   *         to the profile path.
+   * @param  {Function} options.recordStepTelemetry
+   *         A function with the signature `(name: String, took: Number,
+   *         counts: Array?)`, where `name` is the name of the merge step,
+   *         `took` is the time taken in milliseconds, and `counts` is an
+   *         array of named counts (`{ name, count }` tuples) with additional
+   *         counts for the step to record in the telemetry ping.
+   * @param  {Function} options.recordValidationTelemetry
+   *         A function with the signature `(took: Number, checked: Number,
+   *         problems: Array)`, where `took` is the time taken to run
+   *         validation in milliseconds, `checked` is the number of items
+   *         checked, and `problems` is an array of named problem counts.
+   * @param  {AsyncShutdown.Barrier} [options.finalizeAt]
+   *         A shutdown phase, barrier, or barrier client that should
+   *         automatically finalize the mirror when triggered. Exposed for
+   *         testing.
+   * @return {SyncedBookmarksMirror}
+   *         A mirror ready for use.
+   */
+  static async open(options) {
+    let db = await lazy.PlacesUtils.promiseUnsafeWritableDBConnection();
+    if (!db) {
+      throw new TypeError("Can't open mirror without Places connection");
+    }
+    let path;
+    if (PathUtils.isAbsolute(options.path)) {
+      path = options.path;
+    } else {
+      path = PathUtils.join(PathUtils.profileDir, options.path);
+    }
+    let wasCorrupt = false;
+    try {
+      await attachAndInitMirrorDatabase(db, path);
+    } catch (ex) {
+      if (isDatabaseCorrupt(ex)) {
+        lazy.MirrorLog.warn(
+          "Error attaching mirror to Places; removing and " +
+            "recreating mirror",
+          ex
+        );
+        wasCorrupt = true;
+        await IOUtils.remove(path);
+        await attachAndInitMirrorDatabase(db, path);
+      } else {
+        lazy.MirrorLog.error(
+          "Unrecoverable error attaching mirror to Places",
+          ex
+        );
+        throw ex;
+      }
+    }
+    return new SyncedBookmarksMirror(db, wasCorrupt, options);
+  }
+
+  /**
+   * Returns the newer of the bookmarks collection last modified time, or the
+   * server modified time of the newest record. The bookmarks engine uses this
+   * timestamp as the "high water mark" for all downloaded records. Each sync
+   * downloads and stores records that are strictly newer than this time.
+   *
+   * @return {Number}
+   *         The high water mark time, in seconds.
+   */
+  async getCollectionHighWaterMark() {
+    // The first case, where we have records with server modified times newer
+    // than the collection last modified time, occurs when a sync is interrupted
+    // before we call `setCollectionLastModified`. We subtract one second, the
+    // maximum time precision guaranteed by the server, so that we don't miss
+    // other records with the same time as the newest one we downloaded.
+    let rows = await this.db.executeCached(
+      `
+      SELECT MAX(
+        IFNULL((SELECT MAX(serverModified) - 1000 FROM items), 0),
+        IFNULL((SELECT CAST(value AS INTEGER) FROM meta
+                WHERE key = :modifiedKey), 0)
+      ) AS highWaterMark`,
+      { modifiedKey: SyncedBookmarksMirror.META_KEY.LAST_MODIFIED }
+    );
+    let highWaterMark = rows[0].getResultByName("highWaterMark");
+    return highWaterMark / 1000;
+  }
+
+  /**
+   * Updates the bookmarks collection last modified time. Note that this may
+   * be newer than the modified time of the most recent record.
+   *
+   * @param {Number|String} lastModifiedSeconds
+   *        The collection last modified time, in seconds.
+   */
+  async setCollectionLastModified(lastModifiedSeconds) {
+    let lastModified = Math.floor(lastModifiedSeconds * 1000);
+    if (!Number.isInteger(lastModified)) {
+      throw new TypeError("Invalid collection last modified time");
+    }
+    await this.db.executeBeforeShutdown(
+      "SyncedBookmarksMirror: setCollectionLastModified",
+      db =>
+        db.executeCached(
+          `
+        REPLACE INTO meta(key, value)
+        VALUES(:modifiedKey, :lastModified)`,
+          {
+            modifiedKey: SyncedBookmarksMirror.META_KEY.LAST_MODIFIED,
+            lastModified,
+          }
+        )
+    );
+  }
+
+  /**
+   * Returns the bookmarks collection sync ID. This corresponds to
+   * `PlacesSyncUtils.bookmarks.getSyncId`.
+   *
+   * @return {String}
+   *         The sync ID, or `""` if one isn't set.
+   */
+  async getSyncId() {
+    let rows = await this.db.executeCached(
+      `
+      SELECT value FROM meta WHERE key = :syncIdKey`,
+      { syncIdKey: SyncedBookmarksMirror.META_KEY.SYNC_ID }
+    );
+    return rows.length ? rows[0].getResultByName("value") : "";
+  }
+
+  /**
+   * Ensures that the sync ID in the mirror is up-to-date with the server and
+   * Places, and discards the mirror on mismatch.
+   *
+   * The bookmarks engine store the same sync ID in Places and the mirror to
+   * "tie" the two together. This allows Sync to do the right thing if the
+   * database files are copied between profiles connected to different accounts.
+   *
+   * See `PlacesSyncUtils.bookmarks.ensureCurrentSyncId` for an explanation of
+   * how Places handles sync ID mismatches.
+   *
+   * @param {String} newSyncId
+   *        The server's sync ID.
+   */
+  async ensureCurrentSyncId(newSyncId) {
+    if (!newSyncId || typeof newSyncId != "string") {
+      throw new TypeError("Invalid new bookmarks sync ID");
+    }
+    let existingSyncId = await this.getSyncId();
+    if (existingSyncId == newSyncId) {
+      lazy.MirrorLog.trace("Sync ID up-to-date in mirror", { existingSyncId });
+      return;
+    }
+    lazy.MirrorLog.info(
+      "Sync ID changed from ${existingSyncId} to " +
+        "${newSyncId}; resetting mirror",
+      { existingSyncId, newSyncId }
+    );
+    await this.db.executeBeforeShutdown(
+      "SyncedBookmarksMirror: ensureCurrentSyncId",
+      db =>
+        db.executeTransaction(async function () {
+          await resetMirror(db);
+          await db.execute(
+            `
+          REPLACE INTO meta(key, value)
+          VALUES(:syncIdKey, :newSyncId)`,
+            { syncIdKey: SyncedBookmarksMirror.META_KEY.SYNC_ID, newSyncId }
+          );
+        })
+    );
+  }
+
+  /**
+   * Stores incoming or uploaded Sync records in the mirror. Rejects if any
+   * records are invalid.
+   *
+   * @param {PlacesItem[]} records
+   *        Sync records to store in the mirror.
+   * @param {Boolean} [options.needsMerge]
+   *        Indicates if the records were changed remotely since the last sync,
+   *        and should be merged into the local tree. This option is set to
+   *        `true` for incoming records, and `false` for successfully uploaded
+   *        records. Tests can also pass `false` to set up an existing mirror.
+   * @param {AbortSignal} [options.signal]
+   *        An abort signal that can be used to interrupt the operation. If
+   *        omitted, storing incoming items can still be interrupted when the
+   *        mirror is finalized.
+   */
+  async store(records, { needsMerge = true, signal = null } = {}) {
+    let options = {
+      needsMerge,
+      signal: anyAborted(this.finalizeController.signal, signal),
+    };
+    await this.db.executeBeforeShutdown("SyncedBookmarksMirror: store", db =>
+      db.executeTransaction(async () => {
+        for (let record of records) {
+          if (options.signal.aborted) {
+            throw new SyncedBookmarksMirror.InterruptedError(
+              "Interrupted while storing incoming items"
+            );
+          }
+          let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+          if (guid == lazy.PlacesUtils.bookmarks.rootGuid) {
+            // The engine should hard DELETE Places roots from the server.
+            throw new TypeError("Can't store Places root");
+          }
+          if (lazy.MirrorLog.level <= lazy.Log.Level.Trace) {
+            lazy.MirrorLog.trace(
+              `Storing in mirror: ${record.cleartextToString()}`
+            );
+          }
+          switch (record.type) {
+            case "bookmark":
+              await this.storeRemoteBookmark(record, options);
+              continue;
+
+            case "query":
+              await this.storeRemoteQuery(record, options);
+              continue;
+
+            case "folder":
+              await this.storeRemoteFolder(record, options);
+              continue;
+
+            case "livemark":
+              await this.storeRemoteLivemark(record, options);
+              continue;
+
+            case "separator":
+              await this.storeRemoteSeparator(record, options);
+              continue;
+
+            default:
+              if (record.deleted) {
+                await this.storeRemoteTombstone(record, options);
+                continue;
+              }
+          }
+          lazy.MirrorLog.warn("Ignoring record with unknown type", record.type);
+        }
+      })
+    );
+  }
+
+  /**
+   * Builds a complete merged tree from the local and remote trees, resolves
+   * value and structure conflicts, dedupes local items, applies the merged
+   * tree back to Places, and notifies observers about the changes.
+   *
+   * Merging and application happen in a transaction, meaning code that uses the
+   * main Places connection, including the UI, will fail to write to the
+   * database until the transaction commits. Asynchronous consumers will retry
+   * on `SQLITE_BUSY`; synchronous consumers will fail after waiting for 100ms.
+   * See bug 1305563, comment 122 for details.
+   *
+   * @param  {Number} [options.localTimeSeconds]
+   *         The current local time, in seconds.
+   * @param  {Number} [options.remoteTimeSeconds]
+   *         The current server time, in seconds.
+   * @param  {Boolean} [options.notifyInStableOrder]
+   *         If `true`, fire observer notifications for items in the same folder
+   *         in a stable order. This is disabled by default, to avoid the cost
+   *         of sorting the notifications, but enabled in some tests to simplify
+   *         their checks.
+   * @param  {AbortSignal} [options.signal]
+   *         An abort signal that can be used to interrupt a merge when its
+   *         associated `AbortController` is aborted. If omitted, the merge can
+   *         still be interrupted when the mirror is finalized.
+   * @return {Object.<String, BookmarkChangeRecord>}
+   *         A changeset containing locally changed and reconciled records to
+   *         upload to the server, and to store in the mirror once upload
+   *         succeeds.
+   */
+  async apply({
+    localTimeSeconds,
+    remoteTimeSeconds,
+    notifyInStableOrder,
+    signal = null,
+  } = {}) {
+    // We intentionally don't use `executeBeforeShutdown` in this function,
+    // since merging can take a while for large trees, and we don't want to
+    // block shutdown. Since all new items are in the mirror, we'll just try
+    // to merge again on the next sync.
+
+    let finalizeOrInterruptSignal = anyAborted(
+      this.finalizeController.signal,
+      signal
+    );
+
+    let changeRecords;
+    try {
+      changeRecords = await this.tryApply(
+        finalizeOrInterruptSignal,
+        localTimeSeconds,
+        remoteTimeSeconds,
+        notifyInStableOrder
+      );
+    } finally {
+      this.progress.reset();
+    }
+
+    return changeRecords;
+  }
+
+  async tryApply(
+    signal,
+    localTimeSeconds,
+    remoteTimeSeconds,
+    notifyInStableOrder = false
+  ) {
+    let wasMerged = await withTiming("Merging bookmarks in Rust", () =>
+      this.merge(signal, localTimeSeconds, remoteTimeSeconds)
+    );
+
+    if (!wasMerged) {
+      lazy.MirrorLog.debug("No changes detected in both mirror and Places");
+      return {};
+    }
+
+    // At this point, the database is consistent, so we can notify observers and
+    // inflate records for outgoing items.
+
+    let observersToNotify = new BookmarkObserverRecorder(this.db, {
+      signal,
+      notifyInStableOrder,
+    });
+
+    await withTiming(
+      "Notifying Places observers",
+      async () => {
+        try {
+          // Note that we don't use a transaction when fetching info for
+          // observers, so it's possible we might notify with stale info if the
+          // main connection changes Places between the time we finish merging,
+          // and the time we notify observers.
+          await observersToNotify.notifyAll();
+        } catch (ex) {
+          // Places relies on observer notifications to update internal caches.
+          // If notifying observers failed, these caches may be inconsistent,
+          // so we invalidate them just in case.
+          await lazy.PlacesUtils.keywords.invalidateCachedKeywords();
+          lazy.MirrorLog.warn("Error notifying Places observers", ex);
+        } finally {
+          await this.db.executeTransaction(async () => {
+            await this.db.execute(`DELETE FROM itemsAdded`);
+            await this.db.execute(`DELETE FROM guidsChanged`);
+            await this.db.execute(`DELETE FROM itemsChanged`);
+            await this.db.execute(`DELETE FROM itemsRemoved`);
+            await this.db.execute(`DELETE FROM itemsMoved`);
+          });
+        }
+      },
+      time =>
+        this.progress.stepWithTelemetry(
+          ProgressTracker.STEPS.NOTIFY_OBSERVERS,
+          time
+        )
+    );
+
+    let { changeRecords } = await withTiming(
+      "Fetching records for local items to upload",
+      async () => {
+        try {
+          let result = await this.fetchLocalChangeRecords(signal);
+          return result;
+        } finally {
+          await this.db.execute(`DELETE FROM itemsToUpload`);
+        }
+      },
+      (time, result) =>
+        this.progress.stepWithItemCount(
+          ProgressTracker.STEPS.FETCH_LOCAL_CHANGE_RECORDS,
+          time,
+          result.count
+        )
+    );
+
+    return changeRecords;
+  }
+
+  merge(signal, localTimeSeconds = Date.now() / 1000, remoteTimeSeconds = 0) {
+    return new Promise((resolve, reject) => {
+      let op = null;
+      function onAbort() {
+        signal.removeEventListener("abort", onAbort);
+        op.cancel();
+      }
+      let callback = {
+        QueryInterface: ChromeUtils.generateQI([
+          "mozISyncedBookmarksMirrorProgressListener",
+          "mozISyncedBookmarksMirrorCallback",
+        ]),
+        // `mozISyncedBookmarksMirrorProgressListener` methods.
+        onFetchLocalTree: (took, itemCount, deleteCount, problemsBag) => {
+          let counts = [
+            {
+              name: "items",
+              count: itemCount,
+            },
+            {
+              name: "deletions",
+              count: deleteCount,
+            },
+          ];
+          this.progress.stepWithTelemetry(
+            ProgressTracker.STEPS.FETCH_LOCAL_TREE,
+            took,
+            counts
+          );
+          // We don't record local tree problems in validation telemetry.
+        },
+        onFetchRemoteTree: (took, itemCount, deleteCount, problemsBag) => {
+          let counts = [
+            {
+              name: "items",
+              count: itemCount,
+            },
+            {
+              name: "deletions",
+              count: deleteCount,
+            },
+          ];
+          this.progress.stepWithTelemetry(
+            ProgressTracker.STEPS.FETCH_REMOTE_TREE,
+            took,
+            counts
+          );
+          // Record validation telemetry for problems in the remote tree.
+          let problems = bagToNamedCounts(problemsBag, [
+            "orphans",
+            "misparentedRoots",
+            "multipleParents",
+            "nonFolderParents",
+            "parentChildDisagreements",
+            "missingChildren",
+          ]);
+          let checked = itemCount + deleteCount;
+          this.recordValidationTelemetry(took, checked, problems);
+        },
+        onMerge: (took, countsBag) => {
+          let counts = bagToNamedCounts(countsBag, [
+            "items",
+            "dupes",
+            "remoteRevives",
+            "localDeletes",
+            "localRevives",
+            "remoteDeletes",
+          ]);
+          this.progress.stepWithTelemetry(
+            ProgressTracker.STEPS.MERGE,
+            took,
+            counts
+          );
+        },
+        onApply: took => {
+          this.progress.stepWithTelemetry(ProgressTracker.STEPS.APPLY, took);
+        },
+        // `mozISyncedBookmarksMirrorCallback` methods.
+        handleSuccess(result) {
+          signal.removeEventListener("abort", onAbort);
+          resolve(result);
+        },
+        handleError(code, message) {
+          signal.removeEventListener("abort", onAbort);
+          switch (code) {
+            case Cr.NS_ERROR_STORAGE_BUSY:
+              reject(new SyncedBookmarksMirror.MergeConflictError(message));
+              break;
+
+            case Cr.NS_ERROR_ABORT:
+              reject(new SyncedBookmarksMirror.InterruptedError(message));
+              break;
+
+            default:
+              reject(new SyncedBookmarksMirror.MergeError(message));
+          }
+        },
+      };
+      op = this.merger.merge(localTimeSeconds, remoteTimeSeconds, callback);
+      if (signal.aborted) {
+        op.cancel();
+      } else {
+        signal.addEventListener("abort", onAbort);
+      }
+    });
+  }
+
+  /**
+   * Discards the mirror contents. This is called when the user is node
+   * reassigned, disables the bookmarks engine, or signs out.
+   */
+  async reset() {
+    await this.db.executeBeforeShutdown("SyncedBookmarksMirror: reset", db =>
+      db.executeTransaction(() => resetMirror(db))
+    );
+  }
+
+  /**
+   * Fetches the GUIDs of all items in the remote tree that need to be merged
+   * into the local tree.
+   *
+   * @return {String[]}
+   *         Remotely changed GUIDs that need to be merged into Places.
+   */
+  async fetchUnmergedGuids() {
+    let rows = await this.db.execute(`
+      SELECT guid FROM items
+      WHERE needsMerge
+      ORDER BY guid`);
+    return rows.map(row => row.getResultByName("guid"));
+  }
+
+  async storeRemoteBookmark(record, { needsMerge, signal }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+
+    let url = validateURL(record.bmkUri);
+    if (url) {
+      await this.maybeStoreRemoteURL(url);
+    }
+
+    let parentGuid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(
+      record.parentid
+    );
+    let serverModified = determineServerModified(record);
+    let dateAdded = determineDateAdded(record);
+    let title = validateTitle(record.title);
+    let keyword = validateKeyword(record.keyword);
+    let validity = url
+      ? Ci.mozISyncedBookmarksMerger.VALIDITY_VALID
+      : Ci.mozISyncedBookmarksMerger.VALIDITY_REPLACE;
+
+    let unknownFields = lazy.PlacesSyncUtils.extractUnknownFields(
+      record.cleartext,
+      [
+        "bmkUri",
+        "description",
+        "keyword",
+        "tags",
+        "title",
+        ...COMMON_UNKNOWN_FIELDS,
+      ]
+    );
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, parentGuid, serverModified, needsMerge, kind,
+                         dateAdded, title, keyword, validity, unknownFields,
+                         urlId)
+      VALUES(:guid, :parentGuid, :serverModified, :needsMerge, :kind,
+             :dateAdded, NULLIF(:title, ''), :keyword, :validity, :unknownFields,
+             (SELECT id FROM urls
+              WHERE hash = hash(:url) AND
+                    url = :url))`,
+      {
+        guid,
+        parentGuid,
+        serverModified,
+        needsMerge,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_BOOKMARK,
+        dateAdded,
+        title,
+        keyword,
+        url: url ? url.href : null,
+        validity,
+        unknownFields,
+      }
+    );
+
+    let tags = record.tags;
+    if (tags && Array.isArray(tags)) {
+      for (let rawTag of tags) {
+        if (signal.aborted) {
+          throw new SyncedBookmarksMirror.InterruptedError(
+            "Interrupted while storing tags for incoming bookmark"
+          );
+        }
+        let tag = validateTag(rawTag);
+        if (!tag) {
+          continue;
+        }
+        await this.db.executeCached(
+          `
+          INSERT INTO tags(itemId, tag)
+          SELECT id, :tag FROM items
+          WHERE guid = :guid`,
+          { tag, guid }
+        );
+      }
+    }
+  }
+
+  async storeRemoteQuery(record, { needsMerge }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+
+    let validity = Ci.mozISyncedBookmarksMerger.VALIDITY_VALID;
+
+    let url = validateURL(record.bmkUri);
+    if (url) {
+      // The query has a valid URL. Determine if we need to rewrite and reupload
+      // it.
+      let params = new URLSearchParams(url.href.slice(url.protocol.length));
+      let type = +params.get("type");
+      if (type == Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAG_CONTENTS) {
+        // Legacy tag queries with this type use a `place:` URL with a `folder`
+        // param that points to the tag folder ID. Rewrite the query to directly
+        // reference the tag stored in its `folderName`, then flag the rewritten
+        // query for reupload.
+        let tagFolderName = validateTag(record.folderName);
+        if (tagFolderName) {
+          try {
+            url.href = `place:tag=${tagFolderName}`;
+            validity = Ci.mozISyncedBookmarksMerger.VALIDITY_REUPLOAD;
+          } catch (ex) {
+            // The tag folder name isn't URL-encoded (bug 1449939), so we might
+            // produce an invalid URL. However, invalid URLs are already likely
+            // to cause other issues, and it's better to replace or delete the
+            // query than break syncing or the Firefox UI.
+            url = null;
+          }
+        } else {
+          // The tag folder name is invalid, so replace or delete the remote
+          // copy.
+          url = null;
+        }
+      } else {
+        let folder = params.get("folder");
+        if (folder && !params.has("excludeItems")) {
+          // We don't sync enough information to rewrite other queries with a
+          // `folder` param (bug 1377175). Referencing a nonexistent folder ID
+          // causes the query to return all items in the database, so we add
+          // `excludeItems=1` to stop it from doing so. We also flag the
+          // rewritten query for reupload.
+          try {
+            url.href = `${url.href}&excludeItems=1`;
+            validity = Ci.mozISyncedBookmarksMerger.VALIDITY_REUPLOAD;
+          } catch (ex) {
+            url = null;
+          }
+        }
+      }
+
+      // Other queries are implicitly valid, and don't need to be reuploaded
+      // or replaced.
+    }
+
+    if (url) {
+      await this.maybeStoreRemoteURL(url);
+    } else {
+      // If the query doesn't have a valid URL, we must replace the remote copy
+      // with either a valid local copy, or a tombstone if the query doesn't
+      // exist locally.
+      validity = Ci.mozISyncedBookmarksMerger.VALIDITY_REPLACE;
+    }
+
+    let parentGuid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(
+      record.parentid
+    );
+    let serverModified = determineServerModified(record);
+    let dateAdded = determineDateAdded(record);
+    let title = validateTitle(record.title);
+
+    let unknownFields = lazy.PlacesSyncUtils.extractUnknownFields(
+      record.cleartext,
+      [
+        "bmkUri",
+        "description",
+        "folderName",
+        "keyword",
+        "queryId",
+        "tags",
+        "title",
+        ...COMMON_UNKNOWN_FIELDS,
+      ]
+    );
+
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, parentGuid, serverModified, needsMerge, kind,
+                         dateAdded, title,
+                         urlId,
+                         validity, unknownFields)
+      VALUES(:guid, :parentGuid, :serverModified, :needsMerge, :kind,
+             :dateAdded, NULLIF(:title, ''),
+             (SELECT id FROM urls
+              WHERE hash = hash(:url) AND
+                    url = :url),
+             :validity, :unknownFields)`,
+      {
+        guid,
+        parentGuid,
+        serverModified,
+        needsMerge,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_QUERY,
+        dateAdded,
+        title,
+        url: url ? url.href : null,
+        validity,
+        unknownFields,
+      }
+    );
+  }
+
+  async storeRemoteFolder(record, { needsMerge, signal }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+    let parentGuid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(
+      record.parentid
+    );
+    let serverModified = determineServerModified(record);
+    let dateAdded = determineDateAdded(record);
+    let title = validateTitle(record.title);
+    let unknownFields = lazy.PlacesSyncUtils.extractUnknownFields(
+      record.cleartext,
+      ["children", "description", "title", ...COMMON_UNKNOWN_FIELDS]
+    );
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, parentGuid, serverModified, needsMerge, kind,
+                         dateAdded, title, unknownFields)
+      VALUES(:guid, :parentGuid, :serverModified, :needsMerge, :kind,
+             :dateAdded, NULLIF(:title, ''), :unknownFields)`,
+      {
+        guid,
+        parentGuid,
+        serverModified,
+        needsMerge,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_FOLDER,
+        dateAdded,
+        title,
+        unknownFields,
+      }
+    );
+
+    let children = record.children;
+    if (children && Array.isArray(children)) {
+      let offset = 0;
+      for (let chunk of lazy.PlacesUtils.chunkArray(
+        children,
+        this.db.variableLimit - 1
+      )) {
+        if (signal.aborted) {
+          throw new SyncedBookmarksMirror.InterruptedError(
+            "Interrupted while storing children for incoming folder"
+          );
+        }
+        // Builds a fragment like `(?2, ?1, 0), (?3, ?1, 1), ...`, where ?1 is
+        // the folder's GUID, [?2, ?3] are the first and second child GUIDs
+        // (SQLite binding parameters index from 1), and [0, 1] are the
+        // positions. This lets us store the folder's children using as few
+        // statements as possible.
+        let valuesFragment = Array.from(
+          { length: chunk.length },
+          (_, index) => `(?${index + 2}, ?1, ${offset + index})`
+        ).join(",");
+        await this.db.execute(
+          `
+          INSERT INTO structure(guid, parentGuid, position)
+          VALUES ${valuesFragment}`,
+          [guid, ...chunk.map(lazy.PlacesSyncUtils.bookmarks.recordIdToGuid)]
+        );
+        offset += chunk.length;
+      }
+    }
+  }
+
+  async storeRemoteLivemark(record, { needsMerge }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+    let parentGuid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(
+      record.parentid
+    );
+    let serverModified = determineServerModified(record);
+    let feedURL = validateURL(record.feedUri);
+    let dateAdded = determineDateAdded(record);
+    let title = validateTitle(record.title);
+    let siteURL = validateURL(record.siteUri);
+
+    let validity = feedURL
+      ? Ci.mozISyncedBookmarksMerger.VALIDITY_VALID
+      : Ci.mozISyncedBookmarksMerger.VALIDITY_REPLACE;
+
+    let unknownFields = lazy.PlacesSyncUtils.extractUnknownFields(
+      record.cleartext,
+      [
+        "children",
+        "description",
+        "feedUri",
+        "siteUri",
+        "title",
+        ...COMMON_UNKNOWN_FIELDS,
+      ]
+    );
+
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, parentGuid, serverModified, needsMerge, kind,
+                         dateAdded, title, feedURL, siteURL, validity, unknownFields)
+      VALUES(:guid, :parentGuid, :serverModified, :needsMerge, :kind,
+             :dateAdded, NULLIF(:title, ''), :feedURL, :siteURL, :validity, :unknownFields)`,
+      {
+        guid,
+        parentGuid,
+        serverModified,
+        needsMerge,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_LIVEMARK,
+        dateAdded,
+        title,
+        feedURL: feedURL ? feedURL.href : null,
+        siteURL: siteURL ? siteURL.href : null,
+        validity,
+        unknownFields,
+      }
+    );
+  }
+
+  async storeRemoteSeparator(record, { needsMerge }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+    let parentGuid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(
+      record.parentid
+    );
+    let serverModified = determineServerModified(record);
+    let dateAdded = determineDateAdded(record);
+    let unknownFields = lazy.PlacesSyncUtils.extractUnknownFields(
+      record.cleartext,
+      ["pos", ...COMMON_UNKNOWN_FIELDS]
+    );
+
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, parentGuid, serverModified, needsMerge, kind,
+                         dateAdded, unknownFields)
+      VALUES(:guid, :parentGuid, :serverModified, :needsMerge, :kind,
+             :dateAdded, :unknownFields)`,
+      {
+        guid,
+        parentGuid,
+        serverModified,
+        needsMerge,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_SEPARATOR,
+        dateAdded,
+        unknownFields,
+      }
+    );
+  }
+
+  async storeRemoteTombstone(record, { needsMerge }) {
+    let guid = lazy.PlacesSyncUtils.bookmarks.recordIdToGuid(record.id);
+    let serverModified = determineServerModified(record);
+
+    await this.db.executeCached(
+      `
+      REPLACE INTO items(guid, serverModified, needsMerge, isDeleted)
+      VALUES(:guid, :serverModified, :needsMerge, 1)`,
+      { guid, serverModified, needsMerge }
+    );
+  }
+
+  async maybeStoreRemoteURL(url) {
+    await this.db.executeCached(
+      `
+      INSERT OR IGNORE INTO urls(guid, url, hash, revHost)
+      VALUES(IFNULL((SELECT guid FROM urls
+                     WHERE hash = hash(:url) AND
+                                  url = :url),
+                    GENERATE_GUID()), :url, hash(:url), :revHost)`,
+      { url: url.href, revHost: lazy.PlacesUtils.getReversedHost(url) }
+    );
+  }
+
+  /**
+   * Inflates Sync records for all staged outgoing items.
+   *
+   * @param  {AbortSignal} signal
+   *         Stops fetching records when the associated `AbortController`
+   *         is aborted.
+   * @return {Object}
+   *         A `{ changeRecords, count }` tuple, where `changeRecords` is a
+   *         changeset containing Sync record cleartexts for outgoing items and
+   *         tombstones, keyed by their Sync record IDs, and `count` is the
+   *         number of records.
+   */
+  async fetchLocalChangeRecords(signal) {
+    let changeRecords = {};
+    let childRecordIdsByLocalParentId = new Map();
+    let tagsByLocalId = new Map();
+
+    let childGuidRows = [];
+    await this.db.execute(
+      `SELECT parentId, guid FROM structureToUpload
+       ORDER BY parentId, position`,
+      null,
+      (row, cancel) => {
+        if (signal.aborted) {
+          cancel();
+        } else {
+          // `Sqlite.sys.mjs` callbacks swallow exceptions (bug 1387775), so we
+          // accumulate all rows in an array, and process them after.
+          childGuidRows.push(row);
+        }
+      }
+    );
+
+    await lazy.Async.yieldingForEach(
+      childGuidRows,
+      row => {
+        if (signal.aborted) {
+          throw new SyncedBookmarksMirror.InterruptedError(
+            "Interrupted while fetching structure to upload"
+          );
+        }
+        let localParentId = row.getResultByName("parentId");
+        let childRecordId = lazy.PlacesSyncUtils.bookmarks.guidToRecordId(
+          row.getResultByName("guid")
+        );
+        let childRecordIds = childRecordIdsByLocalParentId.get(localParentId);
+        if (childRecordIds) {
+          childRecordIds.push(childRecordId);
+        } else {
+          childRecordIdsByLocalParentId.set(localParentId, [childRecordId]);
+        }
+      },
+      lazy.yieldState
+    );
+
+    let tagRows = [];
+    await this.db.execute(
+      `SELECT id, tag FROM tagsToUpload`,
+      null,
+      (row, cancel) => {
+        if (signal.aborted) {
+          cancel();
+        } else {
+          tagRows.push(row);
+        }
+      }
+    );
+
+    await lazy.Async.yieldingForEach(
+      tagRows,
+      row => {
+        if (signal.aborted) {
+          throw new SyncedBookmarksMirror.InterruptedError(
+            "Interrupted while fetching tags to upload"
+          );
+        }
+        let localId = row.getResultByName("id");
+        let tag = row.getResultByName("tag");
+        let tags = tagsByLocalId.get(localId);
+        if (tags) {
+          tags.push(tag);
+        } else {
+          tagsByLocalId.set(localId, [tag]);
+        }
+      },
+      lazy.yieldState
+    );
+
+    let itemRows = [];
+    await this.db.execute(
+      `SELECT id, syncChangeCounter, guid, isDeleted, type, isQuery,
+              tagFolderName, keyword, url, IFNULL(title, '') AS title,
+              position, parentGuid, unknownFields,
+              IFNULL(parentTitle, '') AS parentTitle, dateAdded
+       FROM itemsToUpload`,
+      null,
+      (row, cancel) => {
+        if (signal.interrupted) {
+          cancel();
+        } else {
+          itemRows.push(row);
+        }
+      }
+    );
+
+    await lazy.Async.yieldingForEach(
+      itemRows,
+      row => {
+        if (signal.aborted) {
+          throw new SyncedBookmarksMirror.InterruptedError(
+            "Interrupted while fetching items to upload"
+          );
+        }
+        let syncChangeCounter = row.getResultByName("syncChangeCounter");
+
+        let guid = row.getResultByName("guid");
+        let recordId = lazy.PlacesSyncUtils.bookmarks.guidToRecordId(guid);
+
+        // Tombstones don't carry additional properties.
+        let isDeleted = row.getResultByName("isDeleted");
+        if (isDeleted) {
+          changeRecords[recordId] = new BookmarkChangeRecord(
+            syncChangeCounter,
+            {
+              id: recordId,
+              deleted: true,
+            }
+          );
+          return;
+        }
+
+        let parentGuid = row.getResultByName("parentGuid");
+        let parentRecordId =
+          lazy.PlacesSyncUtils.bookmarks.guidToRecordId(parentGuid);
+
+        let unknownFieldsRow = row.getResultByName("unknownFields");
+        let unknownFields = unknownFieldsRow
+          ? JSON.parse(unknownFieldsRow)
+          : null;
+        let type = row.getResultByName("type");
+        switch (type) {
+          case lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK: {
+            let isQuery = row.getResultByName("isQuery");
+            if (isQuery) {
+              let queryCleartext = {
+                id: recordId,
+                type: "query",
+                // We ignore `parentid` and use the parent's `children`, but older
+                // Desktops and Android use `parentid` as the canonical parent.
+                // iOS is stricter and requires both `children` and `parentid` to
+                // match.
+                parentid: parentRecordId,
+                // Older Desktops use `hasDupe` (along with `parentName` for
+                // deduping), if hasDupe is true, then they won't attempt deduping
+                // (since they believe that a duplicate for this record should
+                // exist). We set it to true to prevent them from applying their
+                // deduping logic.
+                hasDupe: true,
+                parentName: row.getResultByName("parentTitle"),
+                // Omit `dateAdded` from the record if it's not set locally.
+                dateAdded: row.getResultByName("dateAdded") || undefined,
+                bmkUri: row.getResultByName("url"),
+                title: row.getResultByName("title"),
+                // folderName should never be an empty string or null
+                folderName: row.getResultByName("tagFolderName") || undefined,
+                ...unknownFields,
+              };
+              changeRecords[recordId] = new BookmarkChangeRecord(
+                syncChangeCounter,
+                queryCleartext
+              );
+              return;
+            }
+
+            let bookmarkCleartext = {
+              id: recordId,
+              type: "bookmark",
+              parentid: parentRecordId,
+              hasDupe: true,
+              parentName: row.getResultByName("parentTitle"),
+              dateAdded: row.getResultByName("dateAdded") || undefined,
+              bmkUri: row.getResultByName("url"),
+              title: row.getResultByName("title"),
+              ...unknownFields,
+            };
+            let keyword = row.getResultByName("keyword");
+            if (keyword) {
+              bookmarkCleartext.keyword = keyword;
+            }
+            let localId = row.getResultByName("id");
+            let tags = tagsByLocalId.get(localId);
+            if (tags) {
+              bookmarkCleartext.tags = tags;
+            }
+            changeRecords[recordId] = new BookmarkChangeRecord(
+              syncChangeCounter,
+              bookmarkCleartext
+            );
+            return;
+          }
+
+          case lazy.PlacesUtils.bookmarks.TYPE_FOLDER: {
+            let folderCleartext = {
+              id: recordId,
+              type: "folder",
+              parentid: parentRecordId,
+              hasDupe: true,
+              parentName: row.getResultByName("parentTitle"),
+              dateAdded: row.getResultByName("dateAdded") || undefined,
+              title: row.getResultByName("title"),
+              ...unknownFields,
+            };
+            let localId = row.getResultByName("id");
+            let childRecordIds = childRecordIdsByLocalParentId.get(localId);
+            folderCleartext.children = childRecordIds || [];
+            changeRecords[recordId] = new BookmarkChangeRecord(
+              syncChangeCounter,
+              folderCleartext
+            );
+            return;
+          }
+
+          case lazy.PlacesUtils.bookmarks.TYPE_SEPARATOR: {
+            let separatorCleartext = {
+              id: recordId,
+              type: "separator",
+              parentid: parentRecordId,
+              hasDupe: true,
+              parentName: row.getResultByName("parentTitle"),
+              dateAdded: row.getResultByName("dateAdded") || undefined,
+              // Older Desktops use `pos` for deduping.
+              pos: row.getResultByName("position"),
+              ...unknownFields,
+            };
+            changeRecords[recordId] = new BookmarkChangeRecord(
+              syncChangeCounter,
+              separatorCleartext
+            );
+            return;
+          }
+
+          default:
+            throw new TypeError("Can't create record for unknown Places item");
+        }
+      },
+      lazy.yieldState
+    );
+
+    return { changeRecords, count: itemRows.length };
+  }
+
+  /**
+   * Closes the mirror database connection. This is called automatically on
+   * shutdown, but may also be called explicitly when the mirror is no longer
+   * needed.
+   *
+   * @param {Boolean} [options.alsoCleanup]
+   *                  If specified, drop all temp tables, views, and triggers,
+   *                  and detach from the mirror database before closing the
+   *                  connection. Defaults to `true`.
+   */
+  finalize({ alsoCleanup = true } = {}) {
+    if (!this.finalizePromise) {
+      this.finalizePromise = (async () => {
+        this.progress.step(ProgressTracker.STEPS.FINALIZE);
+        this.finalizeController.abort();
+        this.merger.reset();
+        if (alsoCleanup) {
+          // If the mirror is finalized explicitly, clean up temp entities and
+          // detach from the mirror database. We can skip this for automatic
+          // finalization, since the Places connection is already shutting
+          // down.
+          await cleanupMirrorDatabase(this.db);
+        }
+        await this.db.execute(`PRAGMA mirror.optimize(0x02)`);
+        await this.db.execute(`DETACH mirror`);
+        this.finalizeAt.removeBlocker(this.finalizeBound);
+      })();
+    }
+    return this.finalizePromise;
+  }
+}
+
+/** Key names for the key-value `meta` table. */
+SyncedBookmarksMirror.META_KEY = {
+  LAST_MODIFIED: "collection/lastModified",
+  SYNC_ID: "collection/syncId",
+};
+
+/**
+ * An error thrown when the merge was interrupted.
+ */
+class InterruptedError extends Error {
+  constructor(message) {
+    super(message);
+    this.name = "InterruptedError";
+  }
+}
+SyncedBookmarksMirror.InterruptedError = InterruptedError;
+
+/**
+ * An error thrown when the merge failed for an unexpected reason.
+ */
+class MergeError extends Error {
+  constructor(message) {
+    super(message);
+    this.name = "MergeError";
+  }
+}
+SyncedBookmarksMirror.MergeError = MergeError;
+
+/**
+ * An error thrown when the merge can't proceed because the local tree
+ * changed during the merge.
+ */
+class MergeConflictError extends Error {
+  constructor(message) {
+    super(message);
+    this.name = "MergeConflictError";
+  }
+}
+SyncedBookmarksMirror.MergeConflictError = MergeConflictError;
+
+/**
+ * An error thrown when the mirror database is corrupt, or can't be migrated to
+ * the latest schema version, and must be replaced.
+ */
+class DatabaseCorruptError extends Error {
+  constructor(message) {
+    super(message);
+    this.name = "DatabaseCorruptError";
+  }
+}
+
+// Indicates if the mirror should be replaced because the database file is
+// corrupt.
+function isDatabaseCorrupt(error) {
+  if (error instanceof DatabaseCorruptError) {
+    return true;
+  }
+  if (error.errors) {
+    return error.errors.some(
+      error =>
+        error instanceof Ci.mozIStorageError &&
+        (error.result == Ci.mozIStorageError.CORRUPT ||
+          error.result == Ci.mozIStorageError.NOTADB)
+    );
+  }
+  return false;
+}
+
+/**
+ * Attaches a cloned Places database connection to the mirror database,
+ * migrates the mirror schema to the latest version, and creates temporary
+ * tables, views, and triggers.
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The Places database connection.
+ * @param {String} path
+ *        The full path to the mirror database file.
+ */
+async function attachAndInitMirrorDatabase(db, path) {
+  await db.execute(`ATTACH :path AS mirror`, { path });
+  try {
+    await db.executeTransaction(async function () {
+      let currentSchemaVersion = await db.getSchemaVersion("mirror");
+      if (currentSchemaVersion > 0) {
+        if (currentSchemaVersion < MIRROR_SCHEMA_VERSION) {
+          await migrateMirrorSchema(db, currentSchemaVersion);
+        }
+      } else {
+        await initializeMirrorDatabase(db);
+      }
+      // Downgrading from a newer profile to an older profile rolls back the
+      // schema version, but leaves all new columns in place. We'll run the
+      // migration logic again on the next upgrade.
+      await db.setSchemaVersion(MIRROR_SCHEMA_VERSION, "mirror");
+      await initializeTempMirrorEntities(db);
+    });
+  } catch (ex) {
+    await db.execute(`DETACH mirror`);
+    throw ex;
+  }
+}
+
+/**
+ * Migrates the mirror database schema to the latest version.
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The mirror database connection.
+ * @param {Number} currentSchemaVersion
+ *        The current mirror database schema version.
+ */
+async function migrateMirrorSchema(db, currentSchemaVersion) {
+  if (currentSchemaVersion < 5) {
+    // The mirror was pref'd off by default for schema versions 1-4.
+    throw new DatabaseCorruptError(
+      `Can't migrate from schema version ${currentSchemaVersion}; too old`
+    );
+  }
+  if (currentSchemaVersion < 6) {
+    await db.execute(`CREATE INDEX IF NOT EXISTS mirror.itemURLs ON
+                      items(urlId)`);
+    await db.execute(`CREATE INDEX IF NOT EXISTS mirror.itemKeywords ON
+                      items(keyword) WHERE keyword NOT NULL`);
+  }
+  if (currentSchemaVersion < 7) {
+    await db.execute(`CREATE INDEX IF NOT EXISTS mirror.structurePositions ON
+                      structure(parentGuid, position)`);
+  }
+  if (currentSchemaVersion < 8) {
+    // Not really a "schema" update, but addresses the defect from bug 1635859.
+    // In short, every bookmark with a corresponding entry in the mirror should
+    // have syncStatus = NORMAL.
+    await db.execute(`UPDATE moz_bookmarks AS b
+                      SET syncStatus = ${lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL}
+                      WHERE EXISTS (SELECT 1 FROM mirror.items
+                                    WHERE guid = b.guid)`);
+  }
+  if (currentSchemaVersion < 9) {
+    // Adding unknownFields to the mirror table, which allows us to
+    // keep fields we may not yet understand from other clients and roundtrip
+    // them during the sync process
+    let columns = await db.execute(`PRAGMA table_info(items)`);
+    // migration needs to be idempotent, so we check if the column exists first
+    let exists = columns.find(
+      row => row.getResultByName("name") === "unknownFields"
+    );
+    if (!exists) {
+      await db.execute(`ALTER TABLE items ADD COLUMN unknownFields TEXT`);
+    }
+  }
+}
+
+/**
+ * Initializes a new mirror database, creating persistent tables, indexes, and
+ * roots.
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The mirror database connection.
+ */
+async function initializeMirrorDatabase(db) {
+  // Key-value metadata table. Stores the server collection last modified time
+  // and sync ID.
+  await db.execute(`CREATE TABLE mirror.meta(
+    key TEXT PRIMARY KEY,
+    value NOT NULL
+  ) WITHOUT ROWID`);
+
+  // Note: description and loadInSidebar are not used as of Firefox 63, but
+  // remain to avoid rebuilding the database if the user happens to downgrade.
+  await db.execute(`CREATE TABLE mirror.items(
+    id INTEGER PRIMARY KEY,
+    guid TEXT UNIQUE NOT NULL,
+    /* The "parentid" from the record. */
+    parentGuid TEXT,
+    /* The server modified time, in milliseconds. */
+    serverModified INTEGER NOT NULL DEFAULT 0,
+    needsMerge BOOLEAN NOT NULL DEFAULT 0,
+    validity INTEGER NOT NULL DEFAULT ${Ci.mozISyncedBookmarksMerger.VALIDITY_VALID},
+    isDeleted BOOLEAN NOT NULL DEFAULT 0,
+    kind INTEGER NOT NULL DEFAULT -1,
+    /* The creation date, in milliseconds. */
+    dateAdded INTEGER NOT NULL DEFAULT 0,
+    title TEXT,
+    urlId INTEGER REFERENCES urls(id)
+                  ON DELETE SET NULL,
+    keyword TEXT,
+    description TEXT,
+    loadInSidebar BOOLEAN,
+    smartBookmarkName TEXT,
+    feedURL TEXT,
+    siteURL TEXT,
+    unknownFields TEXT
+  )`);
+
+  await db.execute(`CREATE TABLE mirror.structure(
+    guid TEXT,
+    parentGuid TEXT REFERENCES items(guid)
+                    ON DELETE CASCADE,
+    position INTEGER NOT NULL,
+    PRIMARY KEY(parentGuid, guid)
+  ) WITHOUT ROWID`);
+
+  await db.execute(`CREATE TABLE mirror.urls(
+    id INTEGER PRIMARY KEY,
+    guid TEXT NOT NULL,
+    url TEXT NOT NULL,
+    hash INTEGER NOT NULL,
+    revHost TEXT NOT NULL
+  )`);
+
+  await db.execute(`CREATE TABLE mirror.tags(
+    itemId INTEGER NOT NULL REFERENCES items(id)
+                            ON DELETE CASCADE,
+    tag TEXT NOT NULL
+  )`);
+
+  await db.execute(
+    `CREATE INDEX mirror.structurePositions ON structure(parentGuid, position)`
+  );
+
+  await db.execute(`CREATE INDEX mirror.urlHashes ON urls(hash)`);
+
+  await db.execute(`CREATE INDEX mirror.itemURLs ON items(urlId)`);
+
+  await db.execute(`CREATE INDEX mirror.itemKeywords ON items(keyword)
+                    WHERE keyword NOT NULL`);
+
+  await createMirrorRoots(db);
+}
+
+/**
+ * Drops all temp tables, views, and triggers used for merging, and detaches
+ * from the mirror database.
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The mirror database connection.
+ */
+async function cleanupMirrorDatabase(db) {
+  await db.executeTransaction(async function () {
+    await db.execute(`DROP TABLE changeGuidOps`);
+    await db.execute(`DROP TABLE itemsToApply`);
+    await db.execute(`DROP TABLE applyNewLocalStructureOps`);
+    await db.execute(`DROP VIEW localTags`);
+    await db.execute(`DROP TABLE itemsAdded`);
+    await db.execute(`DROP TABLE guidsChanged`);
+    await db.execute(`DROP TABLE itemsChanged`);
+    await db.execute(`DROP TABLE itemsMoved`);
+    await db.execute(`DROP TABLE itemsRemoved`);
+    await db.execute(`DROP TABLE itemsToUpload`);
+    await db.execute(`DROP TABLE structureToUpload`);
+    await db.execute(`DROP TABLE tagsToUpload`);
+  });
+}
+
+/**
+ * Sets up the syncable roots. All items in the mirror we apply will descend
+ * from these roots - however, malformed records from the server which create
+ * a different root *will* be created in the mirror - just not applied.
+ *
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The mirror database connection.
+ */
+async function createMirrorRoots(db) {
+  const syncableRoots = [
+    {
+      guid: lazy.PlacesUtils.bookmarks.rootGuid,
+      // The Places root is its own parent, to satisfy the foreign key and
+      // `NOT NULL` constraints on `structure`.
+      parentGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+      position: -1,
+      needsMerge: false,
+    },
+    ...lazy.PlacesUtils.bookmarks.userContentRoots.map((guid, position) => {
+      return {
+        guid,
+        parentGuid: lazy.PlacesUtils.bookmarks.rootGuid,
+        position,
+        needsMerge: true,
+      };
+    }),
+  ];
+
+  for (let { guid, parentGuid, position, needsMerge } of syncableRoots) {
+    await db.executeCached(
+      `
+      INSERT INTO items(guid, parentGuid, kind, needsMerge)
+      VALUES(:guid, :parentGuid, :kind, :needsMerge)`,
+      {
+        guid,
+        parentGuid,
+        kind: Ci.mozISyncedBookmarksMerger.KIND_FOLDER,
+        needsMerge,
+      }
+    );
+
+    await db.executeCached(
+      `
+      INSERT INTO structure(guid, parentGuid, position)
+      VALUES(:guid, :parentGuid, :position)`,
+      { guid, parentGuid, position }
+    );
+  }
+}
+
+/**
+ * Creates temporary tables, views, and triggers to apply the mirror to Places.
+ *
+ * @param {Sqlite.OpenedConnection} db
+ *        The mirror database connection.
+ */
+async function initializeTempMirrorEntities(db) {
+  await db.execute(`CREATE TEMP TABLE changeGuidOps(
+    localGuid TEXT PRIMARY KEY,
+    mergedGuid TEXT UNIQUE NOT NULL,
+    syncStatus INTEGER,
+    level INTEGER NOT NULL,
+    lastModifiedMicroseconds INTEGER NOT NULL
+  ) WITHOUT ROWID`);
+
+  await db.execute(`
+    CREATE TEMP TRIGGER changeGuids
+    AFTER DELETE ON changeGuidOps
+    BEGIN
+      /* Record item changed notifications for the updated GUIDs. */
+      INSERT INTO guidsChanged(itemId, oldGuid, level)
+      SELECT b.id, OLD.localGuid, OLD.level
+      FROM moz_bookmarks b
+      WHERE b.guid = OLD.localGuid;
+
+      UPDATE moz_bookmarks SET
+        guid = OLD.mergedGuid,
+        lastModified = OLD.lastModifiedMicroseconds,
+        syncStatus = IFNULL(OLD.syncStatus, syncStatus)
+      WHERE guid = OLD.localGuid;
+    END`);
+
+  await db.execute(`CREATE TEMP TABLE itemsToApply(
+    mergedGuid TEXT PRIMARY KEY,
+    localId INTEGER UNIQUE,
+    remoteId INTEGER UNIQUE NOT NULL,
+    remoteGuid TEXT UNIQUE NOT NULL,
+    newLevel INTEGER NOT NULL,
+    newType INTEGER NOT NULL,
+    localDateAddedMicroseconds INTEGER,
+    remoteDateAddedMicroseconds INTEGER NOT NULL,
+    lastModifiedMicroseconds INTEGER NOT NULL,
+    oldTitle TEXT,
+    newTitle TEXT,
+    oldPlaceId INTEGER,
+    newPlaceId INTEGER,
+    newKeyword TEXT
+  )`);
+
+  await db.execute(`CREATE INDEX existingItems ON itemsToApply(localId)
+                    WHERE localId NOT NULL`);
+
+  await db.execute(`CREATE INDEX oldPlaceIds ON itemsToApply(oldPlaceId)
+                    WHERE oldPlaceId NOT NULL`);
+
+  await db.execute(`CREATE INDEX newPlaceIds ON itemsToApply(newPlaceId)
+                    WHERE newPlaceId NOT NULL`);
+
+  await db.execute(`CREATE INDEX newKeywords ON itemsToApply(newKeyword)
+                    WHERE newKeyword NOT NULL`);
+
+  await db.execute(`CREATE TEMP TABLE applyNewLocalStructureOps(
+    mergedGuid TEXT PRIMARY KEY,
+    mergedParentGuid TEXT NOT NULL,
+    position INTEGER NOT NULL,
+    level INTEGER NOT NULL,
+    lastModifiedMicroseconds INTEGER NOT NULL
+  ) WITHOUT ROWID`);
+
+  await db.execute(`
+    CREATE TEMP TRIGGER applyNewLocalStructure
+    AFTER DELETE ON applyNewLocalStructureOps
+    BEGIN
+      INSERT INTO itemsMoved(itemId, oldParentId, oldParentGuid, oldPosition,
+                             level)
+      SELECT b.id, p.id, p.guid, b.position, OLD.level
+      FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      WHERE b.guid = OLD.mergedGuid;
+
+      UPDATE moz_bookmarks SET
+        parent = (SELECT id FROM moz_bookmarks
+                  WHERE guid = OLD.mergedParentGuid),
+        position = OLD.position,
+        lastModified = OLD.lastModifiedMicroseconds
+      WHERE guid = OLD.mergedGuid;
+    END`);
+
+  // A view of local bookmark tags. Tags, like keywords, are associated with
+  // URLs, so two bookmarks with the same URL should have the same tags. Unlike
+  // keywords, one tag may be associated with many different URLs. Tags are also
+  // different because they're implemented as bookmarks under the hood. Each tag
+  // is stored as a folder under the tags root, and tagged URLs are stored as
+  // untitled bookmarks under these folders. This complexity can be removed once
+  // bug 424160 lands.
+  await db.execute(`
+    CREATE TEMP VIEW localTags(tagEntryId, tagEntryGuid, tagFolderId,
+                               tagFolderGuid, tagEntryPosition, tagEntryType,
+                               tag, placeId, lastModifiedMicroseconds) AS
+    SELECT b.id, b.guid, p.id, p.guid, b.position, b.type,
+           p.title, b.fk, b.lastModified
+    FROM moz_bookmarks b
+    JOIN moz_bookmarks p ON p.id = b.parent
+    WHERE b.type = ${lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK} AND
+          p.parent = (SELECT id FROM moz_bookmarks
+                      WHERE guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}')`);
+
+  // Untags a URL by removing its tag entry.
+  await db.execute(`
+    CREATE TEMP TRIGGER untagLocalPlace
+    INSTEAD OF DELETE ON localTags
+    BEGIN
+      /* Record an item removed notification for the tag entry. */
+      INSERT INTO itemsRemoved(itemId, parentId, position, type, placeId, guid,
+                               parentGuid, title, isUntagging)
+      VALUES(OLD.tagEntryId, OLD.tagFolderId, OLD.tagEntryPosition,
+             OLD.tagEntryType, OLD.placeId, OLD.tagEntryGuid,
+             OLD.tagFolderGuid, OLD.tag, 1);
+
+      DELETE FROM moz_bookmarks WHERE id = OLD.tagEntryId;
+
+      /* Fix the positions of the sibling tag entries. */
+      UPDATE moz_bookmarks SET
+        position = position - 1
+      WHERE parent = OLD.tagFolderId AND
+            position > OLD.tagEntryPosition;
+    END`);
+
+  // Tags a URL by creating a tag folder if it doesn't exist, then inserting a
+  // tag entry for the URL into the tag folder. `NEW.placeId` can be NULL, in
+  // which case we'll just create the tag folder.
+  await db.execute(`
+    CREATE TEMP TRIGGER tagLocalPlace
+    INSTEAD OF INSERT ON localTags
+    BEGIN
+      /* Ensure the tag folder exists. */
+      INSERT OR IGNORE INTO moz_bookmarks(guid, parent, position, type, title,
+                                          dateAdded, lastModified)
+      VALUES(IFNULL((SELECT b.guid FROM moz_bookmarks b
+                     JOIN moz_bookmarks p ON p.id = b.parent
+                     WHERE b.title = NEW.tag AND
+                           p.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}'),
+                    GENERATE_GUID()),
+             (SELECT id FROM moz_bookmarks
+              WHERE guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}'),
+             (SELECT COUNT(*) FROM moz_bookmarks b
+              JOIN moz_bookmarks p ON p.id = b.parent
+              WHERE p.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}'),
+             ${lazy.PlacesUtils.bookmarks.TYPE_FOLDER}, NEW.tag,
+             NEW.lastModifiedMicroseconds,
+             NEW.lastModifiedMicroseconds);
+
+      /* Record an item added notification if we created a tag folder.
+         "CHANGES()" returns the number of rows affected by the INSERT above:
+         1 if we created the folder, or 0 if the folder already existed. */
+      INSERT INTO itemsAdded(guid, isTagging)
+      SELECT b.guid, 1
+      FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      WHERE CHANGES() > 0 AND
+            b.title = NEW.tag AND
+            p.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}';
+
+      /* Add a tag entry for the URL under the tag folder. Omitting the place
+         ID creates a tag folder without tagging the URL. */
+      INSERT OR IGNORE INTO moz_bookmarks(guid, parent, position, type, fk,
+                                          dateAdded, lastModified)
+      SELECT IFNULL((SELECT b.guid FROM moz_bookmarks b
+                     JOIN moz_bookmarks p ON p.id = b.parent
+                     WHERE b.fk = NEW.placeId AND
+                           p.title = NEW.tag AND
+                           p.parent = (SELECT id FROM moz_bookmarks
+                                       WHERE guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}')),
+                    GENERATE_GUID()),
+             (SELECT b.id FROM moz_bookmarks b
+              JOIN moz_bookmarks p ON p.id = b.parent
+              WHERE p.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}' AND
+                    b.title = NEW.tag),
+             (SELECT COUNT(*) FROM moz_bookmarks b
+              JOIN moz_bookmarks p ON p.id = b.parent
+              WHERE p.title = NEW.tag AND
+                    p.parent = (SELECT id FROM moz_bookmarks
+                                WHERE guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}')),
+             ${lazy.PlacesUtils.bookmarks.TYPE_BOOKMARK}, NEW.placeId,
+             NEW.lastModifiedMicroseconds,
+             NEW.lastModifiedMicroseconds
+      WHERE NEW.placeId NOT NULL;
+
+      /* Record an item added notification for the tag entry. */
+      INSERT INTO itemsAdded(guid, isTagging)
+      SELECT b.guid, 1
+      FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      WHERE CHANGES() > 0 AND
+            b.fk = NEW.placeId AND
+            p.title = NEW.tag AND
+            p.parent = (SELECT id FROM moz_bookmarks
+                        WHERE guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}');
+    END`);
+
+  // Stores properties to pass to `onItem{Added, Changed, Moved, Removed}`
+  // bookmark observers for new, updated, moved, and deleted items.
+  await db.execute(`CREATE TEMP TABLE itemsAdded(
+    guid TEXT PRIMARY KEY,
+    isTagging BOOLEAN NOT NULL DEFAULT 0,
+    keywordChanged BOOLEAN NOT NULL DEFAULT 0,
+    level INTEGER NOT NULL DEFAULT -1
+  ) WITHOUT ROWID`);
+
+  await db.execute(`CREATE INDEX addedItemLevels ON itemsAdded(level)`);
+
+  await db.execute(`CREATE TEMP TABLE guidsChanged(
+    itemId INTEGER PRIMARY KEY,
+    oldGuid TEXT NOT NULL,
+    level INTEGER NOT NULL DEFAULT -1
+  )`);
+
+  await db.execute(`CREATE INDEX changedGuidLevels ON guidsChanged(level)`);
+
+  await db.execute(`CREATE TEMP TABLE itemsChanged(
+    itemId INTEGER PRIMARY KEY,
+    oldTitle TEXT,
+    oldPlaceId INTEGER,
+    keywordChanged BOOLEAN NOT NULL DEFAULT 0,
+    level INTEGER NOT NULL DEFAULT -1
+  )`);
+
+  await db.execute(`CREATE INDEX changedItemLevels ON itemsChanged(level)`);
+
+  await db.execute(`CREATE TEMP TABLE itemsMoved(
+    itemId INTEGER PRIMARY KEY,
+    oldParentId INTEGER NOT NULL,
+    oldParentGuid TEXT NOT NULL,
+    oldPosition INTEGER NOT NULL,
+    level INTEGER NOT NULL DEFAULT -1
+  )`);
+
+  await db.execute(`CREATE INDEX movedItemLevels ON itemsMoved(level)`);
+
+  await db.execute(`CREATE TEMP TABLE itemsRemoved(
+    itemId INTEGER PRIMARY KEY,
+    guid TEXT NOT NULL,
+    parentId INTEGER NOT NULL,
+    position INTEGER NOT NULL,
+    type INTEGER NOT NULL,
+    title TEXT NOT NULL,
+    placeId INTEGER,
+    parentGuid TEXT NOT NULL,
+    /* We record the original level of the removed item in the tree so that we
+       can notify children before parents. */
+    level INTEGER NOT NULL DEFAULT -1,
+    isUntagging BOOLEAN NOT NULL DEFAULT 0,
+    keywordRemoved BOOLEAN NOT NULL DEFAULT 0
+  )`);
+
+  await db.execute(
+    `CREATE INDEX removedItemLevels ON itemsRemoved(level DESC)`
+  );
+
+  // Stores locally changed items staged for upload.
+  await db.execute(`CREATE TEMP TABLE itemsToUpload(
+    id INTEGER PRIMARY KEY,
+    guid TEXT UNIQUE NOT NULL,
+    syncChangeCounter INTEGER NOT NULL,
+    isDeleted BOOLEAN NOT NULL DEFAULT 0,
+    parentGuid TEXT,
+    parentTitle TEXT,
+    dateAdded INTEGER, /* In milliseconds. */
+    type INTEGER,
+    title TEXT,
+    placeId INTEGER,
+    isQuery BOOLEAN NOT NULL DEFAULT 0,
+    url TEXT,
+    tagFolderName TEXT,
+    keyword TEXT,
+    position INTEGER,
+    unknownFields TEXT
+  )`);
+
+  await db.execute(`CREATE TEMP TABLE structureToUpload(
+    guid TEXT PRIMARY KEY,
+    parentId INTEGER NOT NULL REFERENCES itemsToUpload(id)
+                              ON DELETE CASCADE,
+    position INTEGER NOT NULL
+  ) WITHOUT ROWID`);
+
+  await db.execute(
+    `CREATE INDEX parentsToUpload ON structureToUpload(parentId, position)`
+  );
+
+  await db.execute(`CREATE TEMP TABLE tagsToUpload(
+    id INTEGER REFERENCES itemsToUpload(id)
+               ON DELETE CASCADE,
+    tag TEXT,
+    PRIMARY KEY(id, tag)
+  ) WITHOUT ROWID`);
+}
+
+async function resetMirror(db) {
+  await db.execute(`DELETE FROM meta`);
+  await db.execute(`DELETE FROM structure`);
+  await db.execute(`DELETE FROM items`);
+  await db.execute(`DELETE FROM urls`);
+
+  // Since we need to reset the modified times and merge flags for the syncable
+  // roots, we simply delete and recreate them.
+  await createMirrorRoots(db);
+}
+
+// Converts a Sync record's last modified time to milliseconds.
+function determineServerModified(record) {
+  return Math.max(record.modified * 1000, 0) || 0;
+}
+
+// Determines a Sync record's creation date.
+function determineDateAdded(record) {
+  let serverModified = determineServerModified(record);
+  return lazy.PlacesSyncUtils.bookmarks.ratchetTimestampBackwards(
+    record.dateAdded,
+    serverModified
+  );
+}
+
+function validateTitle(rawTitle) {
+  if (typeof rawTitle != "string" || !rawTitle) {
+    return null;
+  }
+  return rawTitle.slice(0, DB_TITLE_LENGTH_MAX);
+}
+
+function validateURL(rawURL) {
+  if (typeof rawURL != "string" || rawURL.length > DB_URL_LENGTH_MAX) {
+    return null;
+  }
+  let url = null;
+  try {
+    url = new URL(rawURL);
+  } catch (ex) {}
+  return url;
+}
+
+function validateKeyword(rawKeyword) {
+  if (typeof rawKeyword != "string") {
+    return null;
+  }
+  let keyword = rawKeyword.trim();
+  // Drop empty keywords.
+  return keyword ? keyword.toLowerCase() : null;
+}
+
+function validateTag(rawTag) {
+  if (typeof rawTag != "string") {
+    return null;
+  }
+  let tag = rawTag.trim();
+  if (!tag || tag.length > lazy.PlacesUtils.bookmarks.MAX_TAG_LENGTH) {
+    // Drop empty and oversized tags.
+    return null;
+  }
+  return tag;
+}
+
+/**
+ * Measures and logs the time taken to execute a function, using a monotonic
+ * clock.
+ *
+ * @param  {String} name
+ *         The name of the operation, used for logging.
+ * @param  {Function} func
+ *         The function to time.
+ * @param  {Function} [recordTiming]
+ *         An optional function with the signature `(time: Number)`, where
+ *         `time` is the measured time.
+ * @return The return value of the timed function.
+ */
+async function withTiming(name, func, recordTiming) {
+  lazy.MirrorLog.debug(name);
+
+  let startTime = Cu.now();
+  let result = await func();
+  let elapsedTime = Cu.now() - startTime;
+
+  lazy.MirrorLog.debug(`${name} took ${elapsedTime.toFixed(3)}ms`);
+  if (typeof recordTiming == "function") {
+    recordTiming(elapsedTime, result);
+  }
+
+  return result;
+}
+
+/**
+ * Fires bookmark and keyword observer notifications for all changes made during
+ * the merge.
+ */
+class BookmarkObserverRecorder {
+  constructor(db, { notifyInStableOrder, signal }) {
+    this.db = db;
+    this.notifyInStableOrder = notifyInStableOrder;
+    this.signal = signal;
+    this.placesEvents = [];
+    this.shouldInvalidateKeywords = false;
+  }
+
+  /**
+   * Fires observer notifications for all changed items, invalidates the
+   * livemark cache if necessary, and recalculates frecencies for changed
+   * URLs. This is called outside the merge transaction.
+   */
+  async notifyAll() {
+    await this.noteAllChanges();
+    if (this.shouldInvalidateKeywords) {
+      await lazy.PlacesUtils.keywords.invalidateCachedKeywords();
+    }
+    this.notifyBookmarkObservers();
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted before recalculating frecencies for new URLs"
+      );
+    }
+  }
+
+  orderBy(level, parent, position) {
+    return `ORDER BY ${
+      this.notifyInStableOrder ? `${level}, ${parent}, ${position}` : level
+    }`;
+  }
+
+  /**
+   * Records Places observer notifications for removed, added, moved, and
+   * changed items.
+   */
+  async noteAllChanges() {
+    lazy.MirrorLog.trace("Recording observer notifications for removed items");
+    // `ORDER BY v.level DESC` sorts deleted children before parents, to ensure
+    // that we update caches in the correct order (bug 1297941).
+    await this.db.execute(
+      `SELECT v.itemId AS id, v.parentId, v.parentGuid, v.position, v.type,
+              (SELECT h.url FROM moz_places h WHERE h.id = v.placeId) AS url,
+              v.title, v.guid, v.isUntagging, v.keywordRemoved
+       FROM itemsRemoved v
+       ${this.orderBy("v.level", "v.parentId", "v.position")}`,
+      null,
+      (row, cancel) => {
+        if (this.signal.aborted) {
+          cancel();
+          return;
+        }
+        let info = {
+          id: row.getResultByName("id"),
+          parentId: row.getResultByName("parentId"),
+          position: row.getResultByName("position"),
+          type: row.getResultByName("type"),
+          urlHref: row.getResultByName("url"),
+          title: row.getResultByName("title"),
+          guid: row.getResultByName("guid"),
+          parentGuid: row.getResultByName("parentGuid"),
+          isUntagging: row.getResultByName("isUntagging"),
+        };
+        this.noteItemRemoved(info);
+        if (row.getResultByName("keywordRemoved")) {
+          this.shouldInvalidateKeywords = true;
+        }
+      }
+    );
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted while recording observer notifications for removed items"
+      );
+    }
+
+    lazy.MirrorLog.trace("Recording observer notifications for changed GUIDs");
+    await this.db.execute(
+      `SELECT b.id, b.lastModified, b.type, b.guid AS newGuid,
+              p.guid AS parentGuid, gp.guid AS grandParentGuid
+       FROM guidsChanged c
+       JOIN moz_bookmarks b ON b.id = c.itemId
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_bookmarks gp ON gp.id = p.parent
+       ${this.orderBy("c.level", "b.parent", "b.position")}`,
+      null,
+      (row, cancel) => {
+        if (this.signal.aborted) {
+          cancel();
+          return;
+        }
+        let info = {
+          id: row.getResultByName("id"),
+          lastModified: row.getResultByName("lastModified"),
+          type: row.getResultByName("type"),
+          newGuid: row.getResultByName("newGuid"),
+          parentGuid: row.getResultByName("parentGuid"),
+          grandParentGuid: row.getResultByName("grandParentGuid"),
+        };
+        this.noteGuidChanged(info);
+      }
+    );
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted while recording observer notifications for changed GUIDs"
+      );
+    }
+
+    lazy.MirrorLog.trace("Recording observer notifications for new items");
+    await this.db.execute(
+      `SELECT b.id, p.id AS parentId, b.position, b.type,
+              IFNULL(b.title, '') AS title, b.dateAdded, b.guid,
+              p.guid AS parentGuid, n.isTagging, n.keywordChanged,
+              h.url AS url, IFNULL(h.frecency, 0) AS frecency,
+              IFNULL(h.hidden, 0) AS hidden,
+              IFNULL(h.visit_count, 0) AS visit_count,
+              h.last_visit_date,
+              (SELECT group_concat(pp.title ORDER BY pp.title)
+               FROM moz_bookmarks bb
+               JOIN moz_bookmarks pp ON pp.id = bb.parent
+               JOIN moz_bookmarks gg ON gg.id = pp.parent
+               WHERE bb.fk = h.id
+               AND gg.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}'
+              ) AS tags,
+              t.guid AS tGuid, t.id AS tId, t.title AS tTitle
+       FROM itemsAdded n
+       JOIN moz_bookmarks b ON b.guid = n.guid
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(url)
+       ${this.orderBy("n.level", "b.parent", "b.position")}`,
+      null,
+      (row, cancel) => {
+        if (this.signal.aborted) {
+          cancel();
+          return;
+        }
+
+        let lastVisitDate = row.getResultByName("last_visit_date");
+
+        let info = {
+          id: row.getResultByName("id"),
+          parentId: row.getResultByName("parentId"),
+          position: row.getResultByName("position"),
+          type: row.getResultByName("type"),
+          urlHref: row.getResultByName("url"),
+          title: row.getResultByName("title"),
+          dateAdded: row.getResultByName("dateAdded"),
+          guid: row.getResultByName("guid"),
+          parentGuid: row.getResultByName("parentGuid"),
+          isTagging: row.getResultByName("isTagging"),
+          frecency: row.getResultByName("frecency"),
+          hidden: row.getResultByName("hidden"),
+          visitCount: row.getResultByName("visit_count"),
+          lastVisitDate: lastVisitDate
+            ? lazy.PlacesUtils.toDate(lastVisitDate).getTime()
+            : null,
+          tags: row.getResultByName("tags"),
+          targetFolderGuid: row.getResultByName("tGuid"),
+          targetFolderItemId: row.getResultByName("tId"),
+          targetFolderTitle: row.getResultByName("tTitle"),
+        };
+
+        this.noteItemAdded(info);
+        if (row.getResultByName("keywordChanged")) {
+          this.shouldInvalidateKeywords = true;
+        }
+      }
+    );
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted while recording observer notifications for new items"
+      );
+    }
+
+    lazy.MirrorLog.trace("Recording observer notifications for moved items");
+    await this.db.execute(
+      `SELECT b.id, b.guid, b.type, p.guid AS newParentGuid, c.oldParentGuid,
+              b.position AS newPosition, c.oldPosition,
+              gp.guid AS grandParentGuid,
+              h.url AS url, IFNULL(b.title, '') AS title,
+              IFNULL(h.frecency, 0) AS frecency, IFNULL(h.hidden, 0) AS hidden,
+              IFNULL(h.visit_count, 0) AS visit_count,
+              b.dateAdded, h.last_visit_date,
+              (SELECT group_concat(pp.title ORDER BY pp.title)
+               FROM moz_bookmarks bb
+               JOIN moz_bookmarks pp ON pp.id = bb.parent
+               JOIN moz_bookmarks gg ON gg.id = pp.parent
+               WHERE bb.fk = h.id
+               AND gg.guid = '${lazy.PlacesUtils.bookmarks.tagsGuid}'
+              ) AS tags
+       FROM itemsMoved c
+       JOIN moz_bookmarks b ON b.id = c.itemId
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_bookmarks gp ON gp.id = p.parent
+       LEFT JOIN moz_places h ON h.id = b.fk
+       ${this.orderBy("c.level", "b.parent", "b.position")}`,
+      null,
+      (row, cancel) => {
+        if (this.signal.aborted) {
+          cancel();
+          return;
+        }
+        let lastVisitDate = row.getResultByName("last_visit_date");
+        let info = {
+          id: row.getResultByName("id"),
+          guid: row.getResultByName("guid"),
+          type: row.getResultByName("type"),
+          newParentGuid: row.getResultByName("newParentGuid"),
+          oldParentGuid: row.getResultByName("oldParentGuid"),
+          newPosition: row.getResultByName("newPosition"),
+          oldPosition: row.getResultByName("oldPosition"),
+          urlHref: row.getResultByName("url"),
+          grandParentGuid: row.getResultByName("grandParentGuid"),
+          title: row.getResultByName("title"),
+          frecency: row.getResultByName("frecency"),
+          hidden: row.getResultByName("hidden"),
+          visitCount: row.getResultByName("visit_count"),
+          dateAdded: lazy.PlacesUtils.toDate(
+            row.getResultByName("dateAdded")
+          ).getTime(),
+          lastVisitDate: lastVisitDate
+            ? lazy.PlacesUtils.toDate(lastVisitDate).getTime()
+            : null,
+          tags: row.getResultByName("tags"),
+        };
+        this.noteItemMoved(info);
+      }
+    );
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted while recording observer notifications for moved items"
+      );
+    }
+
+    lazy.MirrorLog.trace("Recording observer notifications for changed items");
+    await this.db.execute(
+      `SELECT b.id, b.guid, b.lastModified, b.type,
+              IFNULL(b.title, '') AS newTitle,
+              IFNULL(c.oldTitle, '') AS oldTitle,
+              (SELECT h.url FROM moz_places h
+               WHERE h.id = b.fk) AS newURL,
+              (SELECT h.url FROM moz_places h
+               WHERE h.id = c.oldPlaceId) AS oldURL,
+              p.id AS parentId, p.guid AS parentGuid,
+              c.keywordChanged,
+              gp.guid AS grandParentGuid,
+              (SELECT h.url FROM moz_places h WHERE h.id = b.fk) AS url
+       FROM itemsChanged c
+       JOIN moz_bookmarks b ON b.id = c.itemId
+       JOIN moz_bookmarks p ON p.id = b.parent
+       LEFT JOIN moz_bookmarks gp ON gp.id = p.parent
+       ${this.orderBy("c.level", "b.parent", "b.position")}`,
+      null,
+      (row, cancel) => {
+        if (this.signal.aborted) {
+          cancel();
+          return;
+        }
+        let info = {
+          id: row.getResultByName("id"),
+          guid: row.getResultByName("guid"),
+          lastModified: row.getResultByName("lastModified"),
+          type: row.getResultByName("type"),
+          newTitle: row.getResultByName("newTitle"),
+          oldTitle: row.getResultByName("oldTitle"),
+          newURLHref: row.getResultByName("newURL"),
+          oldURLHref: row.getResultByName("oldURL"),
+          parentId: row.getResultByName("parentId"),
+          parentGuid: row.getResultByName("parentGuid"),
+          grandParentGuid: row.getResultByName("grandParentGuid"),
+        };
+        this.noteItemChanged(info);
+        if (row.getResultByName("keywordChanged")) {
+          this.shouldInvalidateKeywords = true;
+        }
+      }
+    );
+    if (this.signal.aborted) {
+      throw new SyncedBookmarksMirror.InterruptedError(
+        "Interrupted while recording observer notifications for changed items"
+      );
+    }
+  }
+
+  noteItemAdded(info) {
+    this.placesEvents.push(
+      new PlacesBookmarkAddition({
+        id: info.id,
+        parentId: info.parentId,
+        index: info.position,
+        url: info.urlHref || "",
+        title: info.title,
+        // Note that both the database and the legacy `onItem{Moved, Removed,
+        // Changed}` notifications use microsecond timestamps, but
+        // `PlacesBookmarkAddition` uses milliseconds.
+        dateAdded: info.dateAdded / 1000,
+        guid: info.guid,
+        parentGuid: info.parentGuid,
+        source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+        itemType: info.type,
+        isTagging: info.isTagging,
+        tags: info.tags,
+        frecency: info.frecency,
+        hidden: info.hidden,
+        visitCount: info.visitCount,
+        lastVisitDate: info.lastVisitDate,
+        targetFolderGuid: info.targetFolderGuid,
+        targetFolderItemId: info.targetFolderItemId,
+        targetFolderTitle: info.targetFolderTitle,
+      })
+    );
+  }
+
+  noteGuidChanged(info) {
+    this.placesEvents.push(
+      new PlacesBookmarkGuid({
+        id: info.id,
+        itemType: info.type,
+        url: info.urlHref,
+        guid: info.newGuid,
+        parentGuid: info.parentGuid,
+        lastModified: info.lastModified,
+        source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+        isTagging:
+          info.parentGuid === lazy.PlacesUtils.bookmarks.tagsGuid ||
+          info.grandParentGuid === lazy.PlacesUtils.bookmarks.tagsGuid,
+      })
+    );
+  }
+
+  noteItemMoved(info) {
+    this.placesEvents.push(
+      new PlacesBookmarkMoved({
+        id: info.id,
+        itemType: info.type,
+        url: info.urlHref,
+        title: info.title,
+        guid: info.guid,
+        parentGuid: info.newParentGuid,
+        source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+        index: info.newPosition,
+        oldParentGuid: info.oldParentGuid,
+        oldIndex: info.oldPosition,
+        isTagging:
+          info.newParentGuid === lazy.PlacesUtils.bookmarks.tagsGuid ||
+          info.grandParentGuid === lazy.PlacesUtils.bookmarks.tagsGuid,
+        tags: info.tags,
+        frecency: info.frecency,
+        hidden: info.hidden,
+        visitCount: info.visitCount,
+        dateAdded: info.dateAdded,
+        lastVisitDate: info.lastVisitDate,
+      })
+    );
+  }
+
+  noteItemChanged(info) {
+    if (info.oldTitle != info.newTitle) {
+      this.placesEvents.push(
+        new PlacesBookmarkTitle({
+          id: info.id,
+          itemType: info.type,
+          url: info.urlHref,
+          guid: info.guid,
+          parentGuid: info.parentGuid,
+          title: info.newTitle,
+          lastModified: info.lastModified,
+          source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+          isTagging:
+            info.parentGuid === lazy.PlacesUtils.bookmarks.tagsGuid ||
+            info.grandParentGuid === lazy.PlacesUtils.bookmarks.tagsGuid,
+        })
+      );
+    }
+    if (info.oldURLHref != info.newURLHref) {
+      this.placesEvents.push(
+        new PlacesBookmarkUrl({
+          id: info.id,
+          itemType: info.type,
+          url: info.newURLHref,
+          guid: info.guid,
+          parentGuid: info.parentGuid,
+          lastModified: info.lastModified,
+          source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+          isTagging:
+            info.parentGuid === lazy.PlacesUtils.bookmarks.tagsGuid ||
+            info.grandParentGuid === lazy.PlacesUtils.bookmarks.tagsGuid,
+        })
+      );
+    }
+  }
+
+  noteItemRemoved(info) {
+    this.placesEvents.push(
+      new PlacesBookmarkRemoved({
+        id: info.id,
+        parentId: info.parentId,
+        index: info.position,
+        url: info.urlHref || "",
+        title: info.title,
+        guid: info.guid,
+        parentGuid: info.parentGuid,
+        source: lazy.PlacesUtils.bookmarks.SOURCES.SYNC,
+        itemType: info.type,
+        isTagging: info.isUntagging,
+        isDescendantRemoval: false,
+      })
+    );
+  }
+
+  notifyBookmarkObservers() {
+    lazy.MirrorLog.trace("Notifying bookmark observers");
+
+    if (this.placesEvents.length) {
+      PlacesObservers.notifyListeners(this.placesEvents);
+    }
+
+    lazy.MirrorLog.trace("Notified bookmark observers");
+  }
+}
+
+/**
+ * Holds Sync metadata and the cleartext for a locally changed record. The
+ * bookmarks engine inflates a Sync record from the cleartext, and updates the
+ * `synced` property for successfully uploaded items.
+ *
+ * At the end of the sync, the engine writes the uploaded cleartext back to the
+ * mirror, and passes the updated change record as part of the changeset to
+ * `PlacesSyncUtils.bookmarks.pushChanges`.
+ */
+class BookmarkChangeRecord {
+  constructor(syncChangeCounter, cleartext) {
+    this.tombstone = cleartext.deleted === true;
+    this.counter = syncChangeCounter;
+    this.cleartext = cleartext;
+    this.synced = false;
+  }
+}
+
+function bagToNamedCounts(bag, names) {
+  let counts = [];
+  for (let name of names) {
+    let count = bag.getProperty(name);
+    if (count > 0) {
+      counts.push({ name, count });
+    }
+  }
+  return counts;
+}
+
+/**
+ * Returns an `AbortSignal` that aborts if either `finalizeSignal` or
+ * `interruptSignal` aborts. This is like `Promise.race`, but for
+ * cancellations.
+ *
+ * @param  {AbortSignal} finalizeSignal
+ * @param  {AbortSignal?} signal
+ * @return {AbortSignal}
+ */
+function anyAborted(finalizeSignal, interruptSignal = null) {
+  if (finalizeSignal.aborted || !interruptSignal) {
+    // If the mirror was already finalized, or we don't have an interrupt
+    // signal for this merge, just use the finalize signal.
+    return finalizeSignal;
+  }
+  if (interruptSignal.aborted) {
+    // If the merge was interrupted, return its already-aborted signal.
+    return interruptSignal;
+  }
+  // Otherwise, we return a new signal that aborts if either the mirror is
+  // finalized, or the merge is interrupted, whichever happens first.
+  let controller = new AbortController();
+  function onAbort() {
+    finalizeSignal.removeEventListener("abort", onAbort);
+    interruptSignal.removeEventListener("abort", onAbort);
+    controller.abort();
+  }
+  finalizeSignal.addEventListener("abort", onAbort);
+  interruptSignal.addEventListener("abort", onAbort);
+  return controller.signal;
+}
+
+// Common unknown fields for places items
+const COMMON_UNKNOWN_FIELDS = [
+  "dateAdded",
+  "hasDupe",
+  "id",
+  "modified",
+  "parentid",
+  "parentName",
+  "type",
+];
+
+// In conclusion, this is why bookmark syncing is hard.
diff --git a/toolkit/components/places/TaggingService.sys.mjs b/toolkit/components/places/TaggingService.sys.mjs
new file mode 100644
index 0000000000..e27c84f844
--- /dev/null
+++ b/toolkit/components/places/TaggingService.sys.mjs
@@ -0,0 +1,565 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { PlacesUtils } from "resource://gre/modules/PlacesUtils.sys.mjs";
+
+const TOPIC_SHUTDOWN = "places-shutdown";
+
+/**
+ * The Places Tagging Service
+ */
+export function TaggingService() {
+  this.handlePlacesEvents = this.handlePlacesEvents.bind(this);
+
+  // Observe bookmarks changes.
+  PlacesUtils.observers.addListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-title-changed",
+    ],
+    this.handlePlacesEvents
+  );
+
+  // Cleanup on shutdown.
+  Services.obs.addObserver(this, TOPIC_SHUTDOWN);
+}
+
+TaggingService.prototype = {
+  /**
+   * Creates a tag container under the tags-root with the given name.
+   *
+   * @param aTagName
+   *        the name for the new tag.
+   * @param aSource
+   *        a change source constant from nsINavBookmarksService::SOURCE_*.
+   * @returns the id of the new tag container.
+   */
+  _createTag: function TS__createTag(aTagName, aSource) {
+    var newFolderId = PlacesUtils.bookmarks.createFolder(
+      PlacesUtils.tagsFolderId,
+      aTagName,
+      PlacesUtils.bookmarks.DEFAULT_INDEX,
+      /* aGuid */ null,
+      aSource
+    );
+    // Add the folder to our local cache, so we can avoid doing this in the
+    // observer that would have to check itemType.
+    this._tagFolders[newFolderId] = aTagName;
+
+    return newFolderId;
+  },
+
+  /**
+   * Checks whether the given uri is tagged with the given tag.
+   *
+   * @param [in] aURI
+   *        url to check for
+   * @param [in] aTagName
+   *        the tag to check for
+   * @returns the item id if the URI is tagged with the given tag, -1
+   *          otherwise.
+   */
+  _getItemIdForTaggedURI: function TS__getItemIdForTaggedURI(aURI, aTagName) {
+    var tagId = this._getItemIdForTag(aTagName);
+    if (tagId == -1) {
+      return -1;
+    }
+    // Using bookmarks service API for this would be a pain.
+    // Until tags implementation becomes sane, go the query way.
+    let db = PlacesUtils.history.DBConnection;
+    let stmt = db.createStatement(
+      `SELECT id FROM moz_bookmarks
+       WHERE parent = :tag_id
+       AND fk = (SELECT id FROM moz_places WHERE url_hash = hash(:page_url) AND url = :page_url)`
+    );
+    stmt.params.tag_id = tagId;
+    stmt.params.page_url = aURI.spec;
+    try {
+      if (stmt.executeStep()) {
+        return stmt.row.id;
+      }
+    } finally {
+      stmt.finalize();
+    }
+    return -1;
+  },
+
+  /**
+   * Returns the folder id for a tag, or -1 if not found.
+   * @param [in] aTag
+   *        string tag to search for
+   * @returns integer id for the bookmark folder for the tag
+   */
+  _getItemIdForTag: function TS_getItemIdForTag(aTagName) {
+    for (var i in this._tagFolders) {
+      if (aTagName.toLowerCase() == this._tagFolders[i].toLowerCase()) {
+        return parseInt(i);
+      }
+    }
+    return -1;
+  },
+  /**
+   * Makes a proper array of tag objects like  { id: number, name: string }.
+   *
+   * @param aTags
+   *        Array of tags.  Entries can be tag names or concrete item id.
+   * @param trim [optional]
+   *        Whether to trim passed-in named tags. Defaults to false.
+   * @return Array of tag objects like { id: number, name: string }.
+   *
+   * @throws Cr.NS_ERROR_INVALID_ARG if any element of the input array is not
+   *         a valid tag.
+   */
+  _convertInputMixedTagsArray(aTags, trim = false) {
+    // Handle sparse array with a .filter.
+    return aTags
+      .filter(tag => tag !== undefined)
+      .map(idOrName => {
+        let tag = {};
+        if (typeof idOrName == "number" && this._tagFolders[idOrName]) {
+          // This is a tag folder id.
+          tag.id = idOrName;
+          // We can't know the name at this point, since a previous tag could
+          // want to change it.
+          tag.__defineGetter__("name", () => this._tagFolders[tag.id]);
+        } else if (
+          typeof idOrName == "string" &&
+          !!idOrName.length &&
+          idOrName.length <= PlacesUtils.bookmarks.MAX_TAG_LENGTH
+        ) {
+          // This is a tag name.
+          tag.name = trim ? idOrName.trim() : idOrName;
+          // We can't know the id at this point, since a previous tag could
+          // have created it.
+          tag.__defineGetter__("id", () => this._getItemIdForTag(tag.name));
+        } else {
+          throw Components.Exception(
+            "Invalid tag value",
+            Cr.NS_ERROR_INVALID_ARG
+          );
+        }
+        return tag;
+      });
+  },
+
+  // nsITaggingService
+  tagURI: function TS_tagURI(aURI, aTags, aSource) {
+    if (!aURI || !aTags || !Array.isArray(aTags) || !aTags.length) {
+      throw Components.Exception(
+        "Invalid value for tags",
+        Cr.NS_ERROR_INVALID_ARG
+      );
+    }
+
+    // This also does some input validation.
+    let tags = this._convertInputMixedTagsArray(aTags, true);
+
+    for (let tag of tags) {
+      if (tag.id == -1) {
+        // Tag does not exist yet, create it.
+        this._createTag(tag.name, aSource);
+      }
+
+      let itemId = this._getItemIdForTaggedURI(aURI, tag.name);
+      if (itemId == -1) {
+        // The provided URI is not yet tagged, add a tag for it.
+        // Note that bookmarks under tag containers must have null titles.
+        PlacesUtils.bookmarks.insertBookmark(
+          tag.id,
+          aURI,
+          PlacesUtils.bookmarks.DEFAULT_INDEX,
+          /* aTitle */ null,
+          /* aGuid */ null,
+          aSource
+        );
+      } else {
+        // Otherwise, bump the tag's timestamp, so that we can increment the
+        // sync change counter for all bookmarks with the URI.
+        PlacesUtils.bookmarks.setItemLastModified(
+          itemId,
+          PlacesUtils.toPRTime(Date.now()),
+          aSource
+        );
+      }
+
+      // Try to preserve user's tag name casing.
+      // Rename the tag container so the Places view matches the most-recent
+      // user-typed value.
+      if (PlacesUtils.bookmarks.getItemTitle(tag.id) != tag.name) {
+        // this._tagFolders is updated by the bookmarks observer.
+        PlacesUtils.bookmarks.setItemTitle(tag.id, tag.name, aSource);
+      }
+    }
+  },
+
+  /**
+   * Removes the tag container from the tags root if the given tag is empty.
+   *
+   * @param aTagId
+   *        the itemId of the tag element under the tags root
+   * @param aSource
+   *        a change source constant from nsINavBookmarksService::SOURCE_*
+   */
+  _removeTagIfEmpty: function TS__removeTagIfEmpty(aTagId, aSource) {
+    let count = 0;
+    let db = PlacesUtils.history.DBConnection;
+    let stmt = db.createStatement(
+      `SELECT count(*) AS count FROM moz_bookmarks
+       WHERE parent = :tag_id`
+    );
+    stmt.params.tag_id = aTagId;
+    try {
+      if (stmt.executeStep()) {
+        count = stmt.row.count;
+      }
+    } finally {
+      stmt.finalize();
+    }
+
+    if (count == 0) {
+      PlacesUtils.bookmarks.removeItem(aTagId, aSource);
+    }
+  },
+
+  // nsITaggingService
+  untagURI: function TS_untagURI(aURI, aTags, aSource) {
+    if (!aURI || (aTags && (!Array.isArray(aTags) || !aTags.length))) {
+      throw Components.Exception(
+        "Invalid value for tags",
+        Cr.NS_ERROR_INVALID_ARG
+      );
+    }
+
+    if (!aTags) {
+      // Passing null should clear all tags for aURI, see the IDL.
+      // XXXmano: write a perf-sensitive version of this code path...
+      aTags = this.getTagsForURI(aURI);
+    }
+
+    // This also does some input validation.
+    let tags = this._convertInputMixedTagsArray(aTags);
+
+    let isAnyTagNotTrimmed = tags.some(tag => /^\s|\s$/.test(tag.name));
+    if (isAnyTagNotTrimmed) {
+      throw Components.Exception(
+        "At least one tag passed to untagURI was not trimmed",
+        Cr.NS_ERROR_INVALID_ARG
+      );
+    }
+
+    for (let tag of tags) {
+      if (tag.id != -1) {
+        // A tag could exist.
+        let itemId = this._getItemIdForTaggedURI(aURI, tag.name);
+        if (itemId != -1) {
+          // There is a tagged item.
+          PlacesUtils.bookmarks.removeItem(itemId, aSource);
+        }
+      }
+    }
+  },
+
+  // nsITaggingService
+  getTagsForURI: function TS_getTagsForURI(aURI) {
+    if (!aURI) {
+      throw Components.Exception("Invalid uri", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    let tags = [];
+    let db = PlacesUtils.history.DBConnection;
+    let stmt = db.createStatement(
+      `SELECT t.id AS folderId
+       FROM moz_bookmarks b
+       JOIN moz_bookmarks t on t.id = b.parent
+       WHERE b.fk = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url) AND
+       t.parent = :tags_root
+       ORDER BY b.lastModified DESC, b.id DESC`
+    );
+    stmt.params.url = aURI.spec;
+    stmt.params.tags_root = PlacesUtils.tagsFolderId;
+    try {
+      while (stmt.executeStep()) {
+        try {
+          tags.push(this._tagFolders[stmt.row.folderId]);
+        } catch (ex) {}
+      }
+    } finally {
+      stmt.finalize();
+    }
+
+    // sort the tag list
+    tags.sort(function (a, b) {
+      return a.toLowerCase().localeCompare(b.toLowerCase());
+    });
+    return tags;
+  },
+
+  __tagFolders: null,
+  get _tagFolders() {
+    if (!this.__tagFolders) {
+      this.__tagFolders = [];
+
+      let db = PlacesUtils.history.DBConnection;
+      let stmt = db.createStatement(
+        "SELECT id, title FROM moz_bookmarks WHERE parent = :tags_root "
+      );
+      stmt.params.tags_root = PlacesUtils.tagsFolderId;
+      try {
+        while (stmt.executeStep()) {
+          this.__tagFolders[stmt.row.id] = stmt.row.title;
+        }
+      } finally {
+        stmt.finalize();
+      }
+    }
+
+    return this.__tagFolders;
+  },
+
+  // nsIObserver
+  observe: function TS_observe(aSubject, aTopic, aData) {
+    if (aTopic == TOPIC_SHUTDOWN) {
+      PlacesUtils.observers.removeListener(
+        [
+          "bookmark-added",
+          "bookmark-removed",
+          "bookmark-moved",
+          "bookmark-title-changed",
+        ],
+        this.handlePlacesEvents
+      );
+      Services.obs.removeObserver(this, TOPIC_SHUTDOWN);
+    }
+  },
+
+  /**
+   * If the only bookmark items associated with aURI are contained in tag
+   * folders, returns the IDs of those items.  This can be the case if
+   * the URI was bookmarked and tagged at some point, but the bookmark was
+   * removed, leaving only the bookmark items in tag folders.  If the URI is
+   * either properly bookmarked or not tagged just returns and empty array.
+   *
+   * @param   aURI
+   *          A URI (string) that may or may not be bookmarked
+   * @returns an array of item ids
+   */
+  _getTaggedItemIdsIfUnbookmarkedURI:
+    function TS__getTaggedItemIdsIfUnbookmarkedURI(url) {
+      var itemIds = [];
+      var isBookmarked = false;
+
+      // Using bookmarks service API for this would be a pain.
+      // Until tags implementation becomes sane, go the query way.
+      let db = PlacesUtils.history.DBConnection;
+      let stmt = db.createStatement(
+        `SELECT id, parent
+       FROM moz_bookmarks
+       WHERE fk = (SELECT id FROM moz_places WHERE url_hash = hash(:page_url) AND url = :page_url)`
+      );
+      stmt.params.page_url = url;
+      try {
+        while (stmt.executeStep() && !isBookmarked) {
+          if (this._tagFolders[stmt.row.parent]) {
+            // This is a tag entry.
+            itemIds.push(stmt.row.id);
+          } else {
+            // This is a real bookmark, so the bookmarked URI is not an orphan.
+            isBookmarked = true;
+          }
+        }
+      } finally {
+        stmt.finalize();
+      }
+
+      return isBookmarked ? [] : itemIds;
+    },
+
+  handlePlacesEvents(events) {
+    for (let event of events) {
+      switch (event.type) {
+        case "bookmark-added":
+          if (
+            !event.isTagging ||
+            event.itemType != PlacesUtils.bookmarks.TYPE_FOLDER
+          ) {
+            continue;
+          }
+
+          this._tagFolders[event.id] = event.title;
+          break;
+        case "bookmark-removed":
+          // Item is a tag folder.
+          if (
+            event.parentId == PlacesUtils.tagsFolderId &&
+            this._tagFolders[event.id]
+          ) {
+            delete this._tagFolders[event.id];
+            break;
+          }
+
+          Services.tm.dispatchToMainThread(() => {
+            if (event.url && !this._tagFolders[event.parentId]) {
+              // Item is a bookmark that was removed from a non-tag folder.
+              // If the only bookmark items now associated with the bookmark's URI are
+              // contained in tag folders, the URI is no longer properly bookmarked, so
+              // untag it.
+              let itemIds = this._getTaggedItemIdsIfUnbookmarkedURI(event.url);
+              for (let i = 0; i < itemIds.length; i++) {
+                try {
+                  PlacesUtils.bookmarks.removeItem(itemIds[i], event.source);
+                } catch (ex) {}
+              }
+            } else if (event.url && this._tagFolders[event.parentId]) {
+              // Item is a tag entry.  If this was the last entry for this tag, remove it.
+              this._removeTagIfEmpty(event.parentId, event.source);
+            }
+          });
+          break;
+        case "bookmark-moved":
+          if (
+            this._tagFolders[event.id] &&
+            PlacesUtils.bookmarks.tagsGuid === event.oldParentGuid &&
+            PlacesUtils.bookmarks.tagsGuid !== event.parentGuid
+          ) {
+            delete this._tagFolders[event.id];
+          }
+          break;
+        case "bookmark-title-changed":
+          if (this._tagFolders[event.id]) {
+            this._tagFolders[event.id] = event.title;
+          }
+          break;
+      }
+    }
+  },
+
+  // nsISupports
+
+  classID: Components.ID("{bbc23860-2553-479d-8b78-94d9038334f7}"),
+
+  QueryInterface: ChromeUtils.generateQI(["nsITaggingService", "nsIObserver"]),
+};
+
+/**
+ * Class tracking a single tag autocomplete search.
+ */
+class TagSearch {
+  constructor(searchString, autocompleteSearch, listener) {
+    // We need a result regardless of having matches.
+    this._result = Cc[
+      "@mozilla.org/autocomplete/simple-result;1"
+    ].createInstance(Ci.nsIAutoCompleteSimpleResult);
+    this._result.setDefaultIndex(0);
+    this._result.setSearchString(searchString);
+
+    this._autocompleteSearch = autocompleteSearch;
+    this._listener = listener;
+  }
+
+  async start() {
+    if (this._canceled) {
+      throw new Error("Can't restart a canceled search");
+    }
+
+    let searchString = this._result.searchString;
+    // Only search on characters for the last tag.
+    let index = Math.max(
+      searchString.lastIndexOf(","),
+      searchString.lastIndexOf(";")
+    );
+    let before = "";
+    if (index != -1) {
+      before = searchString.slice(0, index + 1);
+      searchString = searchString.slice(index + 1);
+      // skip past whitespace
+      var m = searchString.match(/\s+/);
+      if (m) {
+        before += m[0];
+        searchString = searchString.slice(m[0].length);
+      }
+    }
+
+    if (searchString.length) {
+      let tags = await PlacesUtils.bookmarks.fetchTags();
+      if (this._canceled) {
+        return;
+      }
+
+      let lcSearchString = searchString.toLowerCase();
+      let matchingTags = tags
+        .filter(t => t.name.toLowerCase().startsWith(lcSearchString))
+        .map(t => t.name);
+
+      for (let i = 0; i < matchingTags.length; ++i) {
+        let tag = matchingTags[i];
+        // For each match, prepend what the user has typed so far.
+        this._result.appendMatch(before + tag, tag);
+        // In case of many tags, notify once every 10.
+        if (i % 10 == 0) {
+          this._notifyResult(true);
+          // yield to avoid monopolizing the main-thread
+          await new Promise(resolve =>
+            Services.tm.dispatchToMainThread(resolve)
+          );
+          if (this._canceled) {
+            return;
+          }
+        }
+      }
+    }
+
+    // Search is done.
+    this._notifyResult(false);
+  }
+
+  cancel() {
+    this._canceled = true;
+  }
+
+  _notifyResult(searchOngoing) {
+    let resultCode = this._result.matchCount
+      ? "RESULT_SUCCESS"
+      : "RESULT_NOMATCH";
+    if (searchOngoing) {
+      resultCode += "_ONGOING";
+    }
+    this._result.setSearchResult(Ci.nsIAutoCompleteResult[resultCode]);
+    this._listener.onSearchResult(this._autocompleteSearch, this._result);
+  }
+}
+
+// Implements nsIAutoCompleteSearch
+export function TagAutoCompleteSearch() {}
+
+TagAutoCompleteSearch.prototype = {
+  /*
+   * Search for a given string and notify a listener of the result.
+   *
+   * @param searchString - The string to search for
+   * @param searchParam - An extra parameter
+   * @param previousResult - A previous result to use for faster searching
+   * @param listener - A listener to notify when the search is complete
+   */
+  startSearch(searchString, searchParam, previousResult, listener) {
+    if (this._search) {
+      this._search.cancel();
+    }
+    this._search = new TagSearch(searchString, this, listener);
+    this._search.start().catch(console.error);
+  },
+
+  /**
+   * Stop an asynchronous search that is in progress
+   */
+  stopSearch() {
+    this._search.cancel();
+    this._search = null;
+  },
+
+  classID: Components.ID("{1dcc23b0-d4cb-11dc-9ad6-479d56d89593}"),
+  QueryInterface: ChromeUtils.generateQI(["nsIAutoCompleteSearch"]),
+};
diff --git a/toolkit/components/places/VisitInfo.cpp b/toolkit/components/places/VisitInfo.cpp
new file mode 100644
index 0000000000..c957c13a6b
--- /dev/null
+++ b/toolkit/components/places/VisitInfo.cpp
@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VisitInfo.h"
+#include "nsIURI.h"
+
+namespace mozilla {
+namespace places {
+
+////////////////////////////////////////////////////////////////////////////////
+//// VisitInfo
+
+VisitInfo::VisitInfo(int64_t aVisitId, PRTime aVisitDate,
+                     uint32_t aTransitionType,
+                     already_AddRefed<nsIURI> aReferrer)
+    : mVisitId(aVisitId),
+      mVisitDate(aVisitDate),
+      mTransitionType(aTransitionType),
+      mReferrer(aReferrer) {}
+
+VisitInfo::~VisitInfo() = default;
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIVisitInfo
+
+NS_IMETHODIMP
+VisitInfo::GetVisitId(int64_t* _visitId) {
+  *_visitId = mVisitId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+VisitInfo::GetVisitDate(PRTime* _visitDate) {
+  *_visitDate = mVisitDate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+VisitInfo::GetTransitionType(uint32_t* _transitionType) {
+  *_transitionType = mTransitionType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+VisitInfo::GetReferrerURI(nsIURI** _referrer) {
+  NS_IF_ADDREF(*_referrer = mReferrer);
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsISupports
+
+NS_IMPL_ISUPPORTS(VisitInfo, mozIVisitInfo)
+
+}  // namespace places
+}  // namespace mozilla
diff --git a/toolkit/components/places/VisitInfo.h b/toolkit/components/places/VisitInfo.h
new file mode 100644
index 0000000000..7b99cd46a6
--- /dev/null
+++ b/toolkit/components/places/VisitInfo.h
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_places_VisitInfo_h__
+#define mozilla_places_VisitInfo_h__
+
+#include "mozIAsyncHistory.h"
+#include "mozilla/Attributes.h"
+#include "nsCOMPtr.h"
+
+class nsIURI;
+
+namespace mozilla {
+namespace places {
+
+class VisitInfo final : public mozIVisitInfo {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZIVISITINFO
+
+  VisitInfo(int64_t aVisitId, PRTime aVisitDate, uint32_t aTransitionType,
+            already_AddRefed<nsIURI> aReferrer);
+
+ private:
+  ~VisitInfo();
+  const int64_t mVisitId;
+  const PRTime mVisitDate;
+  const uint32_t mTransitionType;
+  nsCOMPtr<nsIURI> mReferrer;
+};
+
+}  // namespace places
+}  // namespace mozilla
+
+#endif  // mozilla_places_VisitInfo_h__
diff --git a/toolkit/components/places/bookmark_sync/Cargo.toml b/toolkit/components/places/bookmark_sync/Cargo.toml
new file mode 100644
index 0000000000..36af67afd0
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/Cargo.toml
@@ -0,0 +1,20 @@
+[package]
+name = "bookmark_sync"
+version = "0.1.0"
+authors = ["Lina Cambridge <lina@yakshaving.ninja>"]
+edition = "2018"
+license = "MPL-2.0"
+
+[dependencies]
+atomic_refcell = "0.1"
+dogear = "0.5.0"
+libc = "0.2"
+log = "0.4"
+cstr = "0.2"
+moz_task = { path = "../../../../xpcom/rust/moz_task" }
+nserror = { path = "../../../../xpcom/rust/nserror" }
+nsstring = { path = "../../../../xpcom/rust/nsstring" }
+storage = { path = "../../../../storage/rust" }
+storage_variant = { path = "../../../../storage/variant" }
+url = "2.4"
+xpcom = { path = "../../../../xpcom/rust/xpcom" }
diff --git a/toolkit/components/places/bookmark_sync/src/driver.rs b/toolkit/components/places/bookmark_sync/src/driver.rs
new file mode 100644
index 0000000000..43bb1f1f79
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/src/driver.rs
@@ -0,0 +1,259 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::{
+    fmt::Write,
+    sync::atomic::{AtomicBool, Ordering},
+    time::Duration,
+};
+
+use dogear::{AbortSignal, Guid, ProblemCounts, StructureCounts, TelemetryEvent};
+use log::{Level, LevelFilter, Log, Metadata, Record};
+use moz_task::{Task, TaskRunnable, ThreadPtrHandle};
+use nserror::nsresult;
+use nsstring::{nsACString, nsCString, nsString};
+use storage_variant::HashPropertyBag;
+use xpcom::interfaces::{mozIServicesLogSink, mozISyncedBookmarksMirrorProgressListener};
+
+extern "C" {
+    fn NS_GeneratePlacesGUID(guid: *mut nsACString) -> nsresult;
+}
+
+fn generate_guid() -> Result<nsCString, nsresult> {
+    let mut guid = nsCString::new();
+    let rv = unsafe { NS_GeneratePlacesGUID(&mut *guid) };
+    if rv.succeeded() {
+        Ok(guid)
+    } else {
+        Err(rv)
+    }
+}
+
+/// An abort controller is used to abort merges running on the storage thread
+/// from the main thread. Its design is based on the DOM API of the same name.
+pub struct AbortController {
+    aborted: AtomicBool,
+}
+
+impl AbortController {
+    /// Signals the store to stop merging as soon as it can.
+    pub fn abort(&self) {
+        self.aborted.store(true, Ordering::Release)
+    }
+}
+
+impl Default for AbortController {
+    fn default() -> AbortController {
+        AbortController {
+            aborted: AtomicBool::new(false),
+        }
+    }
+}
+
+impl AbortSignal for AbortController {
+    fn aborted(&self) -> bool {
+        self.aborted.load(Ordering::Acquire)
+    }
+}
+
+/// The merger driver, created and used on the storage thread.
+pub struct Driver {
+    log: Logger,
+    progress: Option<ThreadPtrHandle<mozISyncedBookmarksMirrorProgressListener>>,
+}
+
+impl Driver {
+    #[inline]
+    pub fn new(
+        log: Logger,
+        progress: Option<ThreadPtrHandle<mozISyncedBookmarksMirrorProgressListener>>,
+    ) -> Driver {
+        Driver { log, progress }
+    }
+}
+
+impl dogear::Driver for Driver {
+    fn generate_new_guid(&self, invalid_guid: &Guid) -> dogear::Result<Guid> {
+        generate_guid()
+            .map_err(|_| dogear::ErrorKind::InvalidGuid(invalid_guid.clone()).into())
+            .and_then(|s| Guid::from_utf8(s.as_ref()))
+    }
+
+    #[inline]
+    fn max_log_level(&self) -> LevelFilter {
+        self.log.max_level
+    }
+
+    #[inline]
+    fn logger(&self) -> &dyn Log {
+        &self.log
+    }
+
+    fn record_telemetry_event(&self, event: TelemetryEvent) {
+        if let Some(ref progress) = self.progress {
+            let task = RecordTelemetryEventTask {
+                progress: progress.clone(),
+                event,
+            };
+            let _ = TaskRunnable::new(
+                "bookmark_sync::Driver::record_telemetry_event",
+                Box::new(task),
+            )
+            .and_then(|r| TaskRunnable::dispatch(r, progress.owning_thread()));
+        }
+    }
+}
+
+pub struct Logger {
+    pub max_level: LevelFilter,
+    logger: Option<ThreadPtrHandle<mozIServicesLogSink>>,
+}
+
+impl Logger {
+    #[inline]
+    pub fn new(
+        max_level: LevelFilter,
+        logger: Option<ThreadPtrHandle<mozIServicesLogSink>>,
+    ) -> Logger {
+        Logger { max_level, logger }
+    }
+}
+
+impl Log for Logger {
+    #[inline]
+    fn enabled(&self, meta: &Metadata) -> bool {
+        self.logger.is_some() && meta.level() <= self.max_level
+    }
+
+    fn log(&self, record: &Record) {
+        if !self.enabled(record.metadata()) {
+            return;
+        }
+        if let Some(logger) = &self.logger {
+            let mut message = nsString::new();
+            match write!(message, "{}", record.args()) {
+                Ok(_) => {
+                    let task = LogTask {
+                        logger: logger.clone(),
+                        level: record.metadata().level(),
+                        message,
+                    };
+                    let _ = TaskRunnable::new("bookmark_sync::Logger::log", Box::new(task))
+                        .and_then(|r| TaskRunnable::dispatch(r, logger.owning_thread()));
+                }
+                Err(_) => {}
+            }
+        }
+    }
+
+    fn flush(&self) {}
+}
+
+/// Logs a message to the mirror logger. This task is created on the async
+/// thread, and dispatched to the main thread.
+struct LogTask {
+    logger: ThreadPtrHandle<mozIServicesLogSink>,
+    level: Level,
+    message: nsString,
+}
+
+impl Task for LogTask {
+    fn run(&self) {
+        let logger = self.logger.get().unwrap();
+        match self.level {
+            Level::Error => unsafe {
+                logger.Error(&*self.message);
+            },
+            Level::Warn => unsafe {
+                logger.Warn(&*self.message);
+            },
+            Level::Debug => unsafe {
+                logger.Debug(&*self.message);
+            },
+            Level::Trace => unsafe {
+                logger.Trace(&*self.message);
+            },
+            _ => {}
+        }
+    }
+
+    fn done(&self) -> Result<(), nsresult> {
+        Ok(())
+    }
+}
+
+/// Calls a progress listener callback for a merge telemetry event. This task is
+/// created on the async thread, and dispatched to the main thread.
+struct RecordTelemetryEventTask {
+    progress: ThreadPtrHandle<mozISyncedBookmarksMirrorProgressListener>,
+    event: TelemetryEvent,
+}
+
+impl Task for RecordTelemetryEventTask {
+    fn run(&self) {
+        let callback = self.progress.get().unwrap();
+        let _ = match &self.event {
+            TelemetryEvent::FetchLocalTree(stats) => unsafe {
+                callback.OnFetchLocalTree(
+                    as_millis(stats.time),
+                    stats.items as i64,
+                    stats.deletions as i64,
+                    problem_counts_to_bag(&stats.problems).bag().coerce(),
+                )
+            },
+            TelemetryEvent::FetchRemoteTree(stats) => unsafe {
+                callback.OnFetchRemoteTree(
+                    as_millis(stats.time),
+                    stats.items as i64,
+                    stats.deletions as i64,
+                    problem_counts_to_bag(&stats.problems).bag().coerce(),
+                )
+            },
+            TelemetryEvent::Merge(time, counts) => unsafe {
+                callback.OnMerge(
+                    as_millis(*time),
+                    structure_counts_to_bag(counts).bag().coerce(),
+                )
+            },
+            TelemetryEvent::Apply(time) => unsafe { callback.OnApply(as_millis(*time)) },
+        };
+    }
+
+    fn done(&self) -> std::result::Result<(), nsresult> {
+        Ok(())
+    }
+}
+
+fn as_millis(d: Duration) -> i64 {
+    d.as_secs() as i64 * 1000 + i64::from(d.subsec_millis())
+}
+
+fn problem_counts_to_bag(problems: &ProblemCounts) -> HashPropertyBag {
+    let mut bag = HashPropertyBag::new();
+    bag.set("orphans", problems.orphans as i64);
+    bag.set("misparentedRoots", problems.misparented_roots as i64);
+    bag.set(
+        "multipleParents",
+        problems.multiple_parents_by_children as i64,
+    );
+    bag.set("missingParents", problems.missing_parent_guids as i64);
+    bag.set("nonFolderParents", problems.non_folder_parent_guids as i64);
+    bag.set(
+        "parentChildDisagreements",
+        problems.parent_child_disagreements as i64,
+    );
+    bag.set("missingChildren", problems.missing_children as i64);
+    bag
+}
+
+fn structure_counts_to_bag(counts: &StructureCounts) -> HashPropertyBag {
+    let mut bag = HashPropertyBag::new();
+    bag.set("remoteRevives", counts.remote_revives as i64);
+    bag.set("localDeletes", counts.local_deletes as i64);
+    bag.set("localRevives", counts.local_revives as i64);
+    bag.set("remoteDeletes", counts.remote_deletes as i64);
+    bag.set("dupes", counts.dupes as i64);
+    bag.set("items", counts.merged_nodes as i64);
+    bag
+}
diff --git a/toolkit/components/places/bookmark_sync/src/error.rs b/toolkit/components/places/bookmark_sync/src/error.rs
new file mode 100644
index 0000000000..5ac7c5b62c
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/src/error.rs
@@ -0,0 +1,106 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::{error, fmt, result, string::FromUtf16Error};
+
+use nserror::{
+    nsresult, NS_ERROR_ABORT, NS_ERROR_FAILURE, NS_ERROR_INVALID_ARG, NS_ERROR_STORAGE_BUSY,
+    NS_ERROR_UNEXPECTED,
+};
+
+pub type Result<T> = result::Result<T, Error>;
+
+#[derive(Debug)]
+pub enum Error {
+    Dogear(dogear::Error),
+    Storage(storage::Error),
+    InvalidLocalRoots,
+    InvalidRemoteRoots,
+    Nsresult(nsresult),
+    UnknownItemType(i64),
+    UnknownItemKind(i64),
+    MalformedString(Box<dyn error::Error + Send + Sync + 'static>),
+    MergeConflict,
+    StorageBusy,
+    UnknownItemValidity(i64),
+    DidNotRun,
+}
+
+impl error::Error for Error {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        match self {
+            Error::Dogear(err) => Some(err),
+            Error::Storage(err) => Some(err),
+            _ => None,
+        }
+    }
+}
+
+impl From<dogear::Error> for Error {
+    fn from(err: dogear::Error) -> Error {
+        Error::Dogear(err)
+    }
+}
+
+impl From<storage::Error> for Error {
+    fn from(err: storage::Error) -> Error {
+        Error::Storage(err)
+    }
+}
+
+impl From<nsresult> for Error {
+    fn from(result: nsresult) -> Error {
+        Error::Nsresult(result)
+    }
+}
+
+impl From<FromUtf16Error> for Error {
+    fn from(error: FromUtf16Error) -> Error {
+        Error::MalformedString(error.into())
+    }
+}
+
+impl From<Error> for nsresult {
+    fn from(error: Error) -> nsresult {
+        match error {
+            Error::Dogear(err) => match err.kind() {
+                dogear::ErrorKind::Abort => NS_ERROR_ABORT,
+                _ => NS_ERROR_FAILURE,
+            },
+            Error::InvalidLocalRoots | Error::InvalidRemoteRoots | Error::DidNotRun => {
+                NS_ERROR_UNEXPECTED
+            }
+            Error::Storage(err) => err.into(),
+            Error::Nsresult(result) => result.clone(),
+            Error::UnknownItemType(_)
+            | Error::UnknownItemKind(_)
+            | Error::MalformedString(_)
+            | Error::UnknownItemValidity(_) => NS_ERROR_INVALID_ARG,
+            Error::MergeConflict | Error::StorageBusy => NS_ERROR_STORAGE_BUSY,
+        }
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Error::Dogear(err) => err.fmt(f),
+            Error::Storage(err) => err.fmt(f),
+            Error::InvalidLocalRoots => f.write_str("The Places roots are invalid"),
+            Error::InvalidRemoteRoots => {
+                f.write_str("The roots in the mirror database are invalid")
+            }
+            Error::Nsresult(result) => write!(f, "Operation failed with {}", result.error_name()),
+            Error::UnknownItemType(typ) => write!(f, "Unknown item type {} in Places", typ),
+            Error::UnknownItemKind(kind) => write!(f, "Unknown item kind {} in mirror", kind),
+            Error::MalformedString(err) => err.fmt(f),
+            Error::MergeConflict => f.write_str("Local tree changed during merge"),
+            Error::StorageBusy => f.write_str("The database is busy"),
+            Error::UnknownItemValidity(validity) => {
+                write!(f, "Unknown item validity {} in database", validity)
+            }
+            Error::DidNotRun => write!(f, "Failed to run merge on storage thread"),
+        }
+    }
+}
diff --git a/toolkit/components/places/bookmark_sync/src/lib.rs b/toolkit/components/places/bookmark_sync/src/lib.rs
new file mode 100644
index 0000000000..a0dadd51c2
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/src/lib.rs
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![allow(non_snake_case)]
+
+#[macro_use]
+extern crate cstr;
+#[macro_use]
+extern crate xpcom;
+
+mod driver;
+mod error;
+mod merger;
+mod store;
+
+use xpcom::{interfaces::mozISyncedBookmarksMerger, RefPtr};
+
+use crate::merger::SyncedBookmarksMerger;
+
+#[no_mangle]
+pub unsafe extern "C" fn NS_NewSyncedBookmarksMerger(
+    result: *mut *const mozISyncedBookmarksMerger,
+) {
+    let merger = SyncedBookmarksMerger::new();
+    RefPtr::new(merger.coerce::<mozISyncedBookmarksMerger>()).forget(&mut *result);
+}
diff --git a/toolkit/components/places/bookmark_sync/src/merger.rs b/toolkit/components/places/bookmark_sync/src/merger.rs
new file mode 100644
index 0000000000..ca0fc17a75
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/src/merger.rs
@@ -0,0 +1,237 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::{cell::RefCell, fmt::Write, mem, sync::Arc};
+
+use atomic_refcell::AtomicRefCell;
+use dogear::Store;
+use log::LevelFilter;
+use moz_task::{Task, TaskRunnable, ThreadPtrHandle, ThreadPtrHolder};
+use nserror::{nsresult, NS_ERROR_NOT_AVAILABLE, NS_OK};
+use nsstring::nsString;
+use storage::Conn;
+use xpcom::{
+    interfaces::{
+        mozIPlacesPendingOperation, mozIServicesLogSink, mozIStorageConnection,
+        mozISyncedBookmarksMirrorCallback, mozISyncedBookmarksMirrorProgressListener,
+    },
+    RefPtr, XpCom,
+};
+
+use crate::driver::{AbortController, Driver, Logger};
+use crate::error;
+use crate::store;
+
+#[xpcom(implement(mozISyncedBookmarksMerger), nonatomic)]
+pub struct SyncedBookmarksMerger {
+    db: RefCell<Option<Conn>>,
+    logger: RefCell<Option<RefPtr<mozIServicesLogSink>>>,
+}
+
+impl SyncedBookmarksMerger {
+    pub fn new() -> RefPtr<SyncedBookmarksMerger> {
+        SyncedBookmarksMerger::allocate(InitSyncedBookmarksMerger {
+            db: RefCell::default(),
+            logger: RefCell::default(),
+        })
+    }
+
+    xpcom_method!(get_db => GetDb() -> *const mozIStorageConnection);
+    fn get_db(&self) -> Result<RefPtr<mozIStorageConnection>, nsresult> {
+        self.db
+            .borrow()
+            .as_ref()
+            .map(|db| RefPtr::new(db.connection()))
+            .ok_or(NS_OK)
+    }
+
+    xpcom_method!(set_db => SetDb(connection: *const mozIStorageConnection));
+    fn set_db(&self, connection: Option<&mozIStorageConnection>) -> Result<(), nsresult> {
+        self.db
+            .replace(connection.map(|connection| Conn::wrap(RefPtr::new(connection))));
+        Ok(())
+    }
+
+    xpcom_method!(get_logger => GetLogger() -> *const mozIServicesLogSink);
+    fn get_logger(&self) -> Result<RefPtr<mozIServicesLogSink>, nsresult> {
+        match *self.logger.borrow() {
+            Some(ref logger) => Ok(logger.clone()),
+            None => Err(NS_OK),
+        }
+    }
+
+    xpcom_method!(set_logger => SetLogger(logger: *const mozIServicesLogSink));
+    fn set_logger(&self, logger: Option<&mozIServicesLogSink>) -> Result<(), nsresult> {
+        self.logger.replace(logger.map(RefPtr::new));
+        Ok(())
+    }
+
+    xpcom_method!(
+        merge => Merge(
+            local_time_seconds: i64,
+            remote_time_seconds: i64,
+            callback: *const mozISyncedBookmarksMirrorCallback
+        ) -> *const mozIPlacesPendingOperation
+    );
+    fn merge(
+        &self,
+        local_time_seconds: i64,
+        remote_time_seconds: i64,
+        callback: &mozISyncedBookmarksMirrorCallback,
+    ) -> Result<RefPtr<mozIPlacesPendingOperation>, nsresult> {
+        let callback = RefPtr::new(callback);
+        let db = match *self.db.borrow() {
+            Some(ref db) => db.clone(),
+            None => return Err(NS_ERROR_NOT_AVAILABLE),
+        };
+        let logger = &*self.logger.borrow();
+        let async_thread = db.thread()?;
+        let controller = Arc::new(AbortController::default());
+        let task = MergeTask::new(
+            &db,
+            Arc::clone(&controller),
+            logger.as_ref().cloned(),
+            local_time_seconds,
+            remote_time_seconds,
+            callback,
+        )?;
+        let runnable = TaskRunnable::new(
+            "bookmark_sync::SyncedBookmarksMerger::merge",
+            Box::new(task),
+        )?;
+        TaskRunnable::dispatch(runnable, &async_thread)?;
+        let op = MergeOp::new(controller);
+        Ok(RefPtr::new(op.coerce()))
+    }
+
+    xpcom_method!(reset => Reset());
+    fn reset(&self) -> Result<(), nsresult> {
+        mem::drop(self.db.borrow_mut().take());
+        mem::drop(self.logger.borrow_mut().take());
+        Ok(())
+    }
+}
+
+struct MergeTask {
+    db: Conn,
+    controller: Arc<AbortController>,
+    max_log_level: LevelFilter,
+    logger: Option<ThreadPtrHandle<mozIServicesLogSink>>,
+    local_time_millis: i64,
+    remote_time_millis: i64,
+    progress: Option<ThreadPtrHandle<mozISyncedBookmarksMirrorProgressListener>>,
+    callback: ThreadPtrHandle<mozISyncedBookmarksMirrorCallback>,
+    result: AtomicRefCell<error::Result<store::ApplyStatus>>,
+}
+
+impl MergeTask {
+    fn new(
+        db: &Conn,
+        controller: Arc<AbortController>,
+        logger: Option<RefPtr<mozIServicesLogSink>>,
+        local_time_seconds: i64,
+        remote_time_seconds: i64,
+        callback: RefPtr<mozISyncedBookmarksMirrorCallback>,
+    ) -> Result<MergeTask, nsresult> {
+        let max_log_level = logger
+            .as_ref()
+            .and_then(|logger| {
+                let mut level = 0i16;
+                unsafe { logger.GetMaxLevel(&mut level) }.to_result().ok()?;
+                Some(level)
+            })
+            .map(|level| match level {
+                mozIServicesLogSink::LEVEL_ERROR => LevelFilter::Error,
+                mozIServicesLogSink::LEVEL_WARN => LevelFilter::Warn,
+                mozIServicesLogSink::LEVEL_DEBUG => LevelFilter::Debug,
+                mozIServicesLogSink::LEVEL_TRACE => LevelFilter::Trace,
+                _ => LevelFilter::Off,
+            })
+            .unwrap_or(LevelFilter::Off);
+        let logger = match logger {
+            Some(logger) => Some(ThreadPtrHolder::new(cstr!("mozIServicesLogSink"), logger)?),
+            None => None,
+        };
+        let progress = callback
+            .query_interface::<mozISyncedBookmarksMirrorProgressListener>()
+            .and_then(|p| {
+                ThreadPtrHolder::new(cstr!("mozISyncedBookmarksMirrorProgressListener"), p).ok()
+            });
+        Ok(MergeTask {
+            db: db.clone(),
+            controller,
+            max_log_level,
+            logger,
+            local_time_millis: local_time_seconds * 1000,
+            remote_time_millis: remote_time_seconds * 1000,
+            progress,
+            callback: ThreadPtrHolder::new(cstr!("mozISyncedBookmarksMirrorCallback"), callback)?,
+            result: AtomicRefCell::new(Err(error::Error::DidNotRun)),
+        })
+    }
+
+    fn merge(&self) -> error::Result<store::ApplyStatus> {
+        let mut db = self.db.clone();
+        if db.transaction_in_progress()? {
+            // If a transaction is already open, we can avoid an unnecessary
+            // merge, since we won't be able to apply the merged tree back to
+            // Places. This is common, especially if the user makes lots of
+            // changes at once. In that case, our merge task might run in the
+            // middle of a `Sqlite.sys.mjs` transaction, and fail when we try to
+            // open our own transaction in `Store::apply`. Since the local
+            // tree might be in an inconsistent state, we can't safely update
+            // Places.
+            return Err(error::Error::StorageBusy);
+        }
+        let log = Logger::new(self.max_log_level, self.logger.clone());
+        let driver = Driver::new(log, self.progress.clone());
+        let mut store = store::Store::new(
+            &mut db,
+            &driver,
+            &self.controller,
+            self.local_time_millis,
+            self.remote_time_millis,
+        );
+        store.validate()?;
+        store.prepare()?;
+        let status = store.merge_with_driver(&driver, &*self.controller)?;
+        Ok(status)
+    }
+}
+
+impl Task for MergeTask {
+    fn run(&self) {
+        *self.result.borrow_mut() = self.merge();
+    }
+
+    fn done(&self) -> Result<(), nsresult> {
+        let callback = self.callback.get().unwrap();
+        match mem::replace(&mut *self.result.borrow_mut(), Err(error::Error::DidNotRun)) {
+            Ok(status) => unsafe { callback.HandleSuccess(status.into()) },
+            Err(err) => {
+                let mut message = nsString::new();
+                write!(message, "{}", err).unwrap();
+                unsafe { callback.HandleError(err.into(), &*message) }
+            }
+        }
+        .to_result()
+    }
+}
+
+#[xpcom(implement(mozIPlacesPendingOperation), atomic)]
+pub struct MergeOp {
+    controller: Arc<AbortController>,
+}
+
+impl MergeOp {
+    pub fn new(controller: Arc<AbortController>) -> RefPtr<MergeOp> {
+        MergeOp::allocate(InitMergeOp { controller })
+    }
+
+    xpcom_method!(cancel => Cancel());
+    fn cancel(&self) -> Result<(), nsresult> {
+        self.controller.abort();
+        Ok(())
+    }
+}
diff --git a/toolkit/components/places/bookmark_sync/src/store.rs b/toolkit/components/places/bookmark_sync/src/store.rs
new file mode 100644
index 0000000000..6e8d8024b4
--- /dev/null
+++ b/toolkit/components/places/bookmark_sync/src/store.rs
@@ -0,0 +1,1322 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::{collections::HashMap, convert::TryFrom, fmt};
+
+use dogear::{
+    debug, warn, AbortSignal, CompletionOps, Content, DeleteLocalItem, Guid, Item, Kind,
+    MergedRoot, Tree, UploadItem, UploadTombstone, Validity,
+};
+use nsstring::nsString;
+use storage::{Conn, Step};
+use url::Url;
+use xpcom::interfaces::{mozISyncedBookmarksMerger, nsINavBookmarksService};
+
+use crate::driver::{AbortController, Driver};
+use crate::error::{Error, Result};
+
+extern "C" {
+    fn NS_NavBookmarksTotalSyncChanges() -> i64;
+}
+
+fn total_sync_changes() -> i64 {
+    unsafe { NS_NavBookmarksTotalSyncChanges() }
+}
+
+// Return all the non-root-roots as a 'sql set' (ie, suitable for use in an
+// IN statement)
+fn user_roots_as_sql_set() -> String {
+    format!(
+        "('{0}', '{1}', '{2}', '{3}', '{4}')",
+        dogear::MENU_GUID,
+        dogear::MOBILE_GUID,
+        dogear::TAGS_GUID,
+        dogear::TOOLBAR_GUID,
+        dogear::UNFILED_GUID
+    )
+}
+
+pub struct Store<'s> {
+    db: &'s mut Conn,
+    driver: &'s Driver,
+    controller: &'s AbortController,
+
+    /// The total Sync change count before merging. We store this before
+    /// accessing Places, and compare the current and stored counts after
+    /// opening our transaction. If they match, we can safely apply the
+    /// tree. Otherwise, we bail and try merging again on the next sync.
+    total_sync_changes: i64,
+
+    local_time_millis: i64,
+    remote_time_millis: i64,
+}
+
+impl<'s> Store<'s> {
+    pub fn new(
+        db: &'s mut Conn,
+        driver: &'s Driver,
+        controller: &'s AbortController,
+        local_time_millis: i64,
+        remote_time_millis: i64,
+    ) -> Store<'s> {
+        Store {
+            db,
+            driver,
+            controller,
+            total_sync_changes: total_sync_changes(),
+            local_time_millis,
+            remote_time_millis,
+        }
+    }
+
+    /// Ensures that all local roots are parented correctly.
+    ///
+    /// The Places root can't be in another folder, or we'll recurse infinitely
+    /// when we try to fetch the local tree.
+    ///
+    /// The five built-in roots should be under the Places root, or we'll build
+    /// and sync an invalid tree (bug 1453994, bug 1472127).
+    pub fn validate(&self) -> Result<()> {
+        self.controller.err_if_aborted()?;
+        let mut statement = self.db.prepare(format!(
+            "SELECT NOT EXISTS(
+               SELECT 1 FROM moz_bookmarks
+               WHERE id = (SELECT parent FROM moz_bookmarks
+                           WHERE guid = '{root}')
+             ) AND NOT EXISTS(
+               SELECT 1 FROM moz_bookmarks b
+               JOIN moz_bookmarks p ON p.id = b.parent
+               WHERE b.guid IN {user_roots} AND
+                     p.guid <> '{root}'
+             )",
+            root = dogear::ROOT_GUID,
+            user_roots = user_roots_as_sql_set(),
+        ))?;
+        let has_valid_roots = match statement.step()? {
+            Some(row) => row.get_by_index::<i64>(0)? == 1,
+            None => false,
+        };
+        if has_valid_roots {
+            Ok(())
+        } else {
+            Err(Error::InvalidLocalRoots)
+        }
+    }
+
+    /// Prepares the mirror database for a merge.
+    pub fn prepare(&self) -> Result<()> {
+        // Sync associates keywords with bookmarks, and doesn't sync POST data;
+        // Places associates keywords with (URL, POST data) pairs, and multiple
+        // bookmarks may have the same URL. When a keyword changes, clients
+        // should reupload all bookmarks with the affected URL (see
+        // `PlacesSyncUtils.bookmarks.addSyncChangesForBookmarksWithURL` and
+        // bug 1328737). Just in case, we flag any remote bookmarks that have
+        // different keywords for the same URL, or the same keyword for
+        // different URLs, for reupload.
+        self.controller.err_if_aborted()?;
+        self.db.exec(format!(
+            "UPDATE items SET
+               validity = {}
+             WHERE validity = {} AND (
+               urlId IN (
+                 /* Same URL, different keywords. `COUNT` ignores NULLs, so
+                    we need to count them separately. This handles cases where
+                    a keyword was removed from one, but not all bookmarks with
+                    the same URL. */
+                 SELECT urlId FROM items
+                 GROUP BY urlId
+                 HAVING COUNT(DISTINCT keyword) +
+                        COUNT(DISTINCT CASE WHEN keyword IS NULL
+                                       THEN 1 END) > 1
+               ) OR keyword IN (
+                 /* Different URLs, same keyword. Bookmarks with keywords but
+                    without URLs are already invalid, so we don't need to handle
+                    NULLs here. */
+                 SELECT keyword FROM items
+                 WHERE keyword NOT NULL
+                 GROUP BY keyword
+                 HAVING COUNT(DISTINCT urlId) > 1
+               )
+             )",
+            mozISyncedBookmarksMerger::VALIDITY_REUPLOAD,
+            mozISyncedBookmarksMerger::VALIDITY_VALID,
+        ))?;
+        Ok(())
+    }
+
+    /// Creates a local tree item from a row in the `localItems` CTE.
+    fn local_row_to_item(&self, step: &Step) -> Result<(Item, Option<Content>)> {
+        let raw_guid: nsString = step.get_by_name("guid")?;
+        let guid = Guid::from_utf16(&*raw_guid)?;
+
+        let raw_url_href: Option<nsString> = step.get_by_name("url")?;
+        let (url, validity) = match raw_url_href {
+            // Local items might have (syntactically) invalid URLs, as in bug
+            // 1615931. If we try to sync these items, other clients will flag
+            // them as invalid (see `SyncedBookmarksMirror#storeRemote{Bookmark,
+            // Query}`), delete them when merging, and upload tombstones for
+            // them. We can avoid this extra round trip by flagging the local
+            // item as invalid. If there's a corresponding remote item with a
+            // valid URL, we'll replace the local item with it; if there isn't,
+            // we'll delete the local item.
+            Some(raw_url_href) => match Url::parse(&String::from_utf16(&*raw_url_href)?) {
+                Ok(url) => (Some(url), Validity::Valid),
+                Err(err) => {
+                    warn!(
+                        self.driver,
+                        "Failed to parse URL for local item {}: {}", guid, err
+                    );
+                    (None, Validity::Replace)
+                }
+            },
+            None => (None, Validity::Valid),
+        };
+
+        let typ: i64 = step.get_by_name("type")?;
+        let kind = match u16::try_from(typ) {
+            Ok(nsINavBookmarksService::TYPE_BOOKMARK) => match url.as_ref() {
+                Some(u) if u.scheme() == "place" => Kind::Query,
+                _ => Kind::Bookmark,
+            },
+            Ok(nsINavBookmarksService::TYPE_FOLDER) => {
+                let is_livemark: i64 = step.get_by_name("isLivemark")?;
+                if is_livemark == 1 {
+                    Kind::Livemark
+                } else {
+                    Kind::Folder
+                }
+            }
+            Ok(nsINavBookmarksService::TYPE_SEPARATOR) => Kind::Separator,
+            _ => return Err(Error::UnknownItemType(typ)),
+        };
+
+        let mut item = Item::new(guid, kind);
+
+        let local_modified: i64 = step.get_by_name_or_default("localModified");
+        item.age = (self.local_time_millis - local_modified).max(0);
+
+        let sync_change_counter: i64 = step.get_by_name("syncChangeCounter")?;
+        item.needs_merge = sync_change_counter > 0;
+
+        item.validity = validity;
+
+        let content = if item.validity == Validity::Replace || item.guid == dogear::ROOT_GUID {
+            None
+        } else {
+            let sync_status: i64 = step.get_by_name("syncStatus")?;
+            match u16::try_from(sync_status) {
+                Ok(nsINavBookmarksService::SYNC_STATUS_NORMAL) => None,
+                _ => match kind {
+                    Kind::Bookmark | Kind::Query => {
+                        let raw_title: nsString = step.get_by_name("title")?;
+                        let title = String::from_utf16(&*raw_title)?;
+                        url.map(|url| Content::Bookmark {
+                            title,
+                            url_href: url.into(),
+                        })
+                    }
+                    Kind::Folder | Kind::Livemark => {
+                        let raw_title: nsString = step.get_by_name("title")?;
+                        let title = String::from_utf16(&*raw_title)?;
+                        Some(Content::Folder { title })
+                    }
+                    Kind::Separator => Some(Content::Separator),
+                },
+            }
+        };
+
+        Ok((item, content))
+    }
+
+    /// Creates a remote tree item from a row in `mirror.items`.
+    fn remote_row_to_item(&self, step: &Step) -> Result<(Item, Option<Content>)> {
+        let raw_guid: nsString = step.get_by_name("guid")?;
+        let guid = Guid::from_utf16(&*raw_guid)?;
+
+        let raw_kind: i64 = step.get_by_name("kind")?;
+        let kind = Kind::from_column(raw_kind)?;
+
+        let mut item = Item::new(guid, kind);
+
+        let remote_modified: i64 = step.get_by_name("serverModified")?;
+        item.age = (self.remote_time_millis - remote_modified).max(0);
+
+        let needs_merge: i32 = step.get_by_name("needsMerge")?;
+        item.needs_merge = needs_merge == 1;
+
+        let raw_validity: i64 = step.get_by_name("validity")?;
+        item.validity = Validity::from_column(raw_validity)?;
+
+        let content = if item.validity == Validity::Replace
+            || item.guid == dogear::ROOT_GUID
+            || !item.needs_merge
+        {
+            None
+        } else {
+            match kind {
+                Kind::Bookmark | Kind::Query => {
+                    let raw_title: nsString = step.get_by_name("title")?;
+                    let title = String::from_utf16(&*raw_title)?;
+                    let raw_url_href: Option<nsString> = step.get_by_name("url")?;
+                    match raw_url_href {
+                        Some(raw_url_href) => {
+                            // Unlike for local items, we don't parse URLs for
+                            // remote items, since `storeRemote{Bookmark,
+                            // Query}` already parses and canonicalizes them
+                            // before inserting them into the mirror database.
+                            let url_href = String::from_utf16(&*raw_url_href)?;
+                            Some(Content::Bookmark { title, url_href })
+                        }
+                        None => None,
+                    }
+                }
+                Kind::Folder | Kind::Livemark => {
+                    let raw_title: nsString = step.get_by_name("title")?;
+                    let title = String::from_utf16(&*raw_title)?;
+                    Some(Content::Folder { title })
+                }
+                Kind::Separator => Some(Content::Separator),
+            }
+        };
+
+        Ok((item, content))
+    }
+}
+
+impl<'s> dogear::Store for Store<'s> {
+    type Ok = ApplyStatus;
+    type Error = Error;
+
+    /// Builds a fully rooted, consistent tree from the items and tombstones in
+    /// Places.
+    fn fetch_local_tree(&self) -> Result<Tree> {
+        let mut root_statement = self.db.prepare(format!(
+            "SELECT guid, type, syncChangeCounter, syncStatus,
+                    lastModified / 1000 AS localModified,
+                    NULL AS url, 0 AS isLivemark
+             FROM moz_bookmarks
+             WHERE guid = '{}'",
+            dogear::ROOT_GUID
+        ))?;
+        let mut builder = match root_statement.step()? {
+            Some(step) => {
+                let (item, _) = self.local_row_to_item(&step)?;
+                Tree::with_root(item)
+            }
+            None => return Err(Error::InvalidLocalRoots),
+        };
+
+        // Add items and contents to the builder, keeping track of their
+        // structure in a separate map. We can't call `p.by_structure(...)`
+        // after adding the item, because this query might return rows for
+        // children before their parents. This approach also lets us scan
+        // `moz_bookmarks` once, using the index on `(b.parent, b.position)`
+        // to avoid a temp B-tree for the `ORDER BY`.
+        let mut child_guids_by_parent_guid: HashMap<Guid, Vec<Guid>> = HashMap::new();
+        let mut items_statement = self.db.prepare(format!(
+            "SELECT b.guid, p.guid AS parentGuid, b.type, b.syncChangeCounter,
+                    b.syncStatus, b.lastModified / 1000 AS localModified,
+                    IFNULL(b.title, '') AS title,
+                    (SELECT h.url FROM moz_places h WHERE h.id = b.fk) AS url,
+                    0 AS isLivemark
+             FROM moz_bookmarks b
+             JOIN moz_bookmarks p ON p.id = b.parent
+             WHERE b.guid <> '{}'
+             ORDER BY b.parent, b.position",
+            dogear::ROOT_GUID,
+        ))?;
+        while let Some(step) = items_statement.step()? {
+            self.controller.err_if_aborted()?;
+            let (item, content) = self.local_row_to_item(&step)?;
+
+            let raw_parent_guid: nsString = step.get_by_name("parentGuid")?;
+            let parent_guid = Guid::from_utf16(&*raw_parent_guid)?;
+            child_guids_by_parent_guid
+                .entry(parent_guid)
+                .or_default()
+                .push(item.guid.clone());
+
+            let mut p = builder.item(item)?;
+            if let Some(content) = content {
+                p.content(content);
+            }
+        }
+
+        // At this point, we've added entries for all items to the tree, so
+        // we can add their structure info.
+        for (parent_guid, child_guids) in &child_guids_by_parent_guid {
+            for child_guid in child_guids {
+                self.controller.err_if_aborted()?;
+                builder.parent_for(child_guid).by_structure(parent_guid)?;
+            }
+        }
+
+        let mut deletions_statement = self.db.prepare("SELECT guid FROM moz_bookmarks_deleted")?;
+        while let Some(step) = deletions_statement.step()? {
+            self.controller.err_if_aborted()?;
+            let raw_guid: nsString = step.get_by_name("guid")?;
+            let guid = Guid::from_utf16(&*raw_guid)?;
+            builder.deletion(guid);
+        }
+
+        let tree = Tree::try_from(builder)?;
+        Ok(tree)
+    }
+
+    /// Builds a fully rooted, consistent tree from the items and tombstones in the
+    /// mirror.
+    fn fetch_remote_tree(&self) -> Result<Tree> {
+        let mut root_statement = self.db.prepare(format!(
+            "SELECT guid, serverModified, kind, needsMerge, validity
+             FROM items
+             WHERE guid = '{}'",
+            dogear::ROOT_GUID,
+        ))?;
+        let mut builder = match root_statement.step()? {
+            Some(step) => {
+                let (item, _) = self.remote_row_to_item(&step)?;
+                Tree::with_root(item)
+            }
+            None => return Err(Error::InvalidRemoteRoots),
+        };
+        builder.reparent_orphans_to(&dogear::UNFILED_GUID);
+
+        let mut items_statement = self.db.prepare(format!(
+            "SELECT v.guid, v.parentGuid, v.serverModified, v.kind,
+                    IFNULL(v.title, '') AS title, v.needsMerge, v.validity,
+                    v.isDeleted,
+                    (SELECT u.url FROM urls u
+                     WHERE u.id = v.urlId) AS url
+             FROM items v
+             WHERE v.guid <> '{}'
+             ORDER BY v.guid",
+            dogear::ROOT_GUID,
+        ))?;
+        while let Some(step) = items_statement.step()? {
+            self.controller.err_if_aborted()?;
+
+            let is_deleted: i64 = step.get_by_name("isDeleted")?;
+            if is_deleted == 1 {
+                let needs_merge: i32 = step.get_by_name("needsMerge")?;
+                if needs_merge == 0 {
+                    // Ignore already-merged tombstones. These aren't persisted
+                    // locally, so merging them is a no-op.
+                    continue;
+                }
+                let raw_guid: nsString = step.get_by_name("guid")?;
+                let guid = Guid::from_utf16(&*raw_guid)?;
+                builder.deletion(guid);
+            } else {
+                let (item, content) = self.remote_row_to_item(&step)?;
+                let mut p = builder.item(item)?;
+                if let Some(content) = content {
+                    p.content(content);
+                }
+                let raw_parent_guid: Option<nsString> = step.get_by_name("parentGuid")?;
+                if let Some(raw_parent_guid) = raw_parent_guid {
+                    p.by_parent_guid(Guid::from_utf16(&*raw_parent_guid)?)?;
+                }
+            }
+        }
+
+        let mut structure_statement = self.db.prepare(format!(
+            "SELECT guid, parentGuid FROM structure
+             WHERE guid <> '{}'
+             ORDER BY parentGuid, position",
+            dogear::ROOT_GUID,
+        ))?;
+        while let Some(step) = structure_statement.step()? {
+            self.controller.err_if_aborted()?;
+            let raw_guid: nsString = step.get_by_name("guid")?;
+            let guid = Guid::from_utf16(&*raw_guid)?;
+
+            let raw_parent_guid: nsString = step.get_by_name("parentGuid")?;
+            let parent_guid = Guid::from_utf16(&*raw_parent_guid)?;
+
+            builder.parent_for(&guid).by_children(&parent_guid)?;
+        }
+
+        let tree = Tree::try_from(builder)?;
+        Ok(tree)
+    }
+
+    fn apply<'t>(&mut self, root: MergedRoot<'t>) -> Result<ApplyStatus> {
+        let ops = root.completion_ops_with_signal(self.controller)?;
+
+        if ops.is_empty() {
+            // If we don't have any items to apply, upload, or delete,
+            // no need to open a transaction at all.
+            return Ok(ApplyStatus::Skipped);
+        }
+
+        // Apply the merged tree and stage outgoing items. This transaction
+        // blocks writes from the main connection until it's committed, so we
+        // try to do as little work as possible within it.
+        if self.db.transaction_in_progress()? {
+            return Err(Error::StorageBusy);
+        }
+        let tx = self.db.transaction()?;
+        if self.total_sync_changes != total_sync_changes() {
+            return Err(Error::MergeConflict);
+        }
+
+        debug!(self.driver, "Updating local items in Places");
+        update_local_items_in_places(
+            &tx,
+            &self.driver,
+            &self.controller,
+            self.local_time_millis,
+            &ops,
+        )?;
+
+        debug!(self.driver, "Staging items to upload");
+        stage_items_to_upload(
+            &tx,
+            &self.driver,
+            &self.controller,
+            &ops.upload_items,
+            &ops.upload_tombstones,
+        )?;
+
+        cleanup(&tx)?;
+        tx.commit()?;
+
+        Ok(ApplyStatus::Merged)
+    }
+}
+
+/// Builds a temporary table with the merge states of all nodes in the merged
+/// tree and updates Places to match the merged tree.
+///
+/// Conceptually, we examine the merge state of each item, and either leave the
+/// item unchanged, upload the local side, apply the remote side, or apply and
+/// then reupload the remote side with a new structure.
+///
+/// Note that we update Places and flag items *before* upload, while iOS
+/// updates the mirror *after* a successful upload. This simplifies our
+/// implementation, though we lose idempotent merges. If upload is interrupted,
+/// the next sync won't distinguish between new merge states from the previous
+/// sync, and local changes.
+fn update_local_items_in_places<'t>(
+    db: &Conn,
+    driver: &Driver,
+    controller: &AbortController,
+    local_time_millis: i64,
+    ops: &CompletionOps<'t>,
+) -> Result<()> {
+    debug!(
+        driver,
+        "Cleaning up observer notifications left from last sync"
+    );
+    controller.err_if_aborted()?;
+    db.exec(
+        "DELETE FROM itemsAdded;
+         DELETE FROM guidsChanged;
+         DELETE FROM itemsChanged;
+         DELETE FROM itemsRemoved;
+         DELETE FROM itemsMoved;",
+    )?;
+
+    // Places uses microsecond timestamps for dates added and last modified
+    // times, rounded to the nearest millisecond. Using `now` for the local
+    // time lets us set modified times deterministically for tests.
+    let now = local_time_millis * 1000;
+
+    // Insert URLs for new remote items into the `moz_places` table. We need to
+    // do this before inserting new remote items, since we need Place IDs for
+    // both old and new URLs.
+    debug!(driver, "Inserting Places for new items");
+    for chunk in ops.apply_remote_items.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "INSERT OR IGNORE INTO moz_places(url, url_hash, rev_host, hidden,
+                                              frecency, guid)
+             SELECT u.url, u.hash, u.revHost,
+                    (CASE WHEN u.url BETWEEN 'place:' AND 'place:' || X'FFFF' THEN 1 ELSE 0 END),
+                    (CASE v.kind WHEN {} THEN 0 ELSE -1 END),
+                    IFNULL((SELECT h.guid FROM moz_places h
+                            WHERE h.url_hash = u.hash AND
+                                  h.url = u.url), u.guid)
+             FROM items v
+             JOIN urls u ON u.id = v.urlId
+             WHERE v.guid IN ({})",
+            mozISyncedBookmarksMerger::KIND_QUERY,
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            let remote_guid = nsString::from(&*op.remote_node().guid);
+            statement.bind_by_index(index as u32, remote_guid)?;
+        }
+        statement.execute()?;
+    }
+
+    // Build a table of new and updated items.
+    debug!(driver, "Staging apply remote item ops");
+    for chunk in ops.apply_remote_items.chunks(db.variable_limit()? / 3) {
+        // CTEs in `WITH` clauses aren't indexed, so this query needs a full
+        // table scan on `ops`. But that's okay; a separate temp table for ops
+        // would also need a full scan. Note that we need both the local _and_
+        // remote GUIDs here, because we haven't changed the local GUIDs yet.
+        let mut statement = db.prepare(format!(
+            "WITH
+             ops(mergedGuid, localGuid, remoteGuid, level) AS (VALUES {})
+             INSERT INTO itemsToApply(mergedGuid, localId, remoteId,
+                                      remoteGuid, newLevel,
+                                      newType,
+                                      localDateAddedMicroseconds,
+                                      remoteDateAddedMicroseconds,
+                                      lastModifiedMicroseconds,
+                                      oldTitle, newTitle, oldPlaceId,
+                                      newPlaceId,
+                                      newKeyword)
+             SELECT n.mergedGuid, b.id, v.id,
+                    v.guid, n.level,
+                    (CASE WHEN v.kind IN ({}, {}) THEN {}
+                          WHEN v.kind IN ({}, {}) THEN {}
+                          ELSE {}
+                     END),
+                    b.dateAdded,
+                    v.dateAdded * 1000,
+                    MAX(v.dateAdded * 1000, {}),
+                    b.title, v.title, b.fk,
+                    (SELECT h.id FROM moz_places h
+                     JOIN urls u ON u.hash = h.url_hash
+                     WHERE u.id = v.urlId AND
+                           u.url = h.url),
+                    v.keyword
+             FROM ops n
+             JOIN items v ON v.guid = n.remoteGuid
+             LEFT JOIN moz_bookmarks b ON b.guid = n.localGuid",
+            repeat_display(chunk.len(), ",", |index, f| {
+                let op = &chunk[index];
+                write!(f, "(?, ?, ?, {})", op.level)
+            }),
+            mozISyncedBookmarksMerger::KIND_BOOKMARK,
+            mozISyncedBookmarksMerger::KIND_QUERY,
+            nsINavBookmarksService::TYPE_BOOKMARK,
+            mozISyncedBookmarksMerger::KIND_FOLDER,
+            mozISyncedBookmarksMerger::KIND_LIVEMARK,
+            nsINavBookmarksService::TYPE_FOLDER,
+            nsINavBookmarksService::TYPE_SEPARATOR,
+            now,
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+
+            let offset = (index * 3) as u32;
+
+            // In most cases, the merged and remote GUIDs are the same for new
+            // items. For updates, all three are typically the same. We could
+            // try to avoid binding duplicates, but that complicates chunking,
+            // and we don't expect many items to change after the first sync.
+            let merged_guid = nsString::from(&*op.merged_node.guid);
+            statement.bind_by_index(offset, merged_guid)?;
+
+            let local_guid = op
+                .merged_node
+                .merge_state
+                .local_node()
+                .map(|node| nsString::from(&*node.guid));
+            statement.bind_by_index(offset + 1, local_guid)?;
+
+            let remote_guid = nsString::from(&*op.remote_node().guid);
+            statement.bind_by_index(offset + 2, remote_guid)?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(driver, "Staging change GUID ops");
+    for chunk in ops.change_guids.chunks(db.variable_limit()? / 2) {
+        let mut statement = db.prepare(format!(
+            "INSERT INTO changeGuidOps(localGuid, mergedGuid, syncStatus, level,
+                                       lastModifiedMicroseconds)
+             VALUES {}",
+            repeat_display(chunk.len(), ",", |index, f| {
+                let op = &chunk[index];
+                // If only the local GUID changed, the item was deduped, so we
+                // can mark it as syncing. Otherwise, we changed an invalid
+                // GUID locally or remotely, so we leave its original sync
+                // status in place until we've uploaded it.
+                let sync_status = if op.merged_node.remote_guid_changed() {
+                    None
+                } else {
+                    Some(nsINavBookmarksService::SYNC_STATUS_NORMAL)
+                };
+                write!(
+                    f,
+                    "(?, ?, {}, {}, {})",
+                    NullableFragment(sync_status),
+                    op.level,
+                    now
+                )
+            })
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+
+            let offset = (index * 2) as u32;
+
+            let local_guid = nsString::from(&*op.local_node().guid);
+            statement.bind_by_index(offset, local_guid)?;
+
+            let merged_guid = nsString::from(&*op.merged_node.guid);
+            statement.bind_by_index(offset + 1, merged_guid)?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(driver, "Staging apply new local structure ops");
+    for chunk in ops
+        .apply_new_local_structure
+        .chunks(db.variable_limit()? / 2)
+    {
+        let mut statement = db.prepare(format!(
+            "INSERT INTO applyNewLocalStructureOps(mergedGuid, mergedParentGuid,
+                                                   position, level,
+                                                   lastModifiedMicroseconds)
+             VALUES {}",
+            repeat_display(chunk.len(), ",", |index, f| {
+                let op = &chunk[index];
+                write!(f, "(?, ?, {}, {}, {})", op.position, op.level, now)
+            })
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+
+            let offset = (index * 2) as u32;
+
+            let merged_guid = nsString::from(&*op.merged_node.guid);
+            statement.bind_by_index(offset, merged_guid)?;
+
+            let merged_parent_guid = nsString::from(&*op.merged_parent_node.guid);
+            statement.bind_by_index(offset + 1, merged_parent_guid)?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(driver, "Removing tombstones for revived items");
+    for chunk in ops.delete_local_tombstones.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "DELETE FROM moz_bookmarks_deleted
+             WHERE guid IN ({})",
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(&*op.guid().as_str()))?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(
+        driver,
+        "Inserting new tombstones for non-syncable and invalid items"
+    );
+    for chunk in ops.insert_local_tombstones.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "INSERT INTO moz_bookmarks_deleted(guid, dateRemoved)
+             VALUES {}",
+            repeat_display(chunk.len(), ",", |_, f| write!(f, "(?, {})", now)),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(
+                index as u32,
+                nsString::from(&*op.remote_node().guid.as_str()),
+            )?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(driver, "Removing local items");
+    for chunk in ops.delete_local_items.chunks(db.variable_limit()?) {
+        remove_local_items(&db, driver, controller, chunk)?;
+    }
+
+    // Fires the `changeGuids` trigger.
+    debug!(driver, "Changing GUIDs");
+    controller.err_if_aborted()?;
+    db.exec("DELETE FROM changeGuidOps")?;
+
+    debug!(driver, "Applying remote items");
+    apply_remote_items(db, driver, controller)?;
+
+    // Fires the `applyNewLocalStructure` trigger.
+    debug!(driver, "Applying new local structure");
+    controller.err_if_aborted()?;
+    db.exec("DELETE FROM applyNewLocalStructureOps")?;
+
+    debug!(
+        driver,
+        "Resetting change counters for items that shouldn't be uploaded"
+    );
+    for chunk in ops.set_local_merged.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "UPDATE moz_bookmarks SET
+               syncChangeCounter = 0
+             WHERE guid IN ({})",
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(&*op.merged_node.guid))?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(
+        driver,
+        "Bumping change counters for items that should be uploaded"
+    );
+    for chunk in ops.set_local_unmerged.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "UPDATE moz_bookmarks SET
+               syncChangeCounter = 1
+             WHERE guid IN ({})",
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(&*op.merged_node.guid))?;
+        }
+        statement.execute()?;
+    }
+
+    debug!(driver, "Flagging applied remote items as merged");
+    for chunk in ops.set_remote_merged.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "UPDATE items SET
+               needsMerge = 0
+             WHERE guid IN ({})",
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(op.guid().as_str()))?;
+        }
+        statement.execute()?;
+    }
+
+    Ok(())
+}
+
+/// Upserts all new and updated items from the `itemsToApply` table into Places.
+fn apply_remote_items(db: &Conn, driver: &Driver, controller: &AbortController) -> Result<()> {
+    debug!(driver, "Recording item added notifications for new items");
+    controller.err_if_aborted()?;
+    db.exec(
+        "INSERT INTO itemsAdded(guid, keywordChanged, level)
+         SELECT n.mergedGuid, n.newKeyword NOT NULL OR
+                              EXISTS(SELECT 1 FROM moz_keywords k
+                                     WHERE k.place_id = n.newPlaceId OR
+                                           k.keyword = n.newKeyword),
+                n.newLevel
+         FROM itemsToApply n
+         WHERE n.localId IS NULL",
+    )?;
+
+    debug!(
+        driver,
+        "Recording item changed notifications for existing items"
+    );
+    controller.err_if_aborted()?;
+    db.exec(
+        "INSERT INTO itemsChanged(itemId, oldTitle, oldPlaceId, keywordChanged,
+                                 level)
+        SELECT n.localId, n.oldTitle, n.oldPlaceId,
+               n.newKeyword NOT NULL OR EXISTS(
+                 SELECT 1 FROM moz_keywords k
+                 WHERE k.place_id IN (n.oldPlaceId, n.newPlaceId) OR
+                       k.keyword = n.newKeyword
+               ),
+               n.newLevel
+        FROM itemsToApply n
+        WHERE n.localId NOT NULL",
+    )?;
+
+    // Remove all keywords from old and new URLs, and remove new keywords from
+    // all existing URLs. The `NOT NULL` conditions are important; they ensure
+    // that SQLite uses our partial indexes, instead of a table scan.
+    debug!(driver, "Removing old keywords");
+    controller.err_if_aborted()?;
+    db.exec(
+        "DELETE FROM moz_keywords
+         WHERE place_id IN (SELECT oldPlaceId FROM itemsToApply
+                            WHERE oldPlaceId NOT NULL) OR
+               place_id IN (SELECT newPlaceId FROM itemsToApply
+                            WHERE newPlaceId NOT NULL) OR
+               keyword IN (SELECT newKeyword FROM itemsToApply
+                           WHERE newKeyword NOT NULL)
+    ",
+    )?;
+
+    debug!(driver, "Removing old tags");
+    controller.err_if_aborted()?;
+    db.exec(
+        "DELETE FROM localTags
+         WHERE placeId IN (SELECT oldPlaceId FROM itemsToApply
+                           WHERE oldPlaceId NOT NULL) OR
+               placeId IN (SELECT newPlaceId FROM itemsToApply
+                           WHERE newPlaceId NOT NULL)",
+    )?;
+
+    // Insert and update items, using -1 for new items' parent IDs and
+    // positions. We'll update these later, when we apply the new local
+    // structure. This is a full table scan on `itemsToApply`. The no-op
+    // `WHERE` clause is necessary to avoid a parsing ambiguity.
+    debug!(driver, "Upserting new items");
+    controller.err_if_aborted()?;
+    db.exec(format!(
+        "INSERT INTO moz_bookmarks(id, guid, parent, position, type, fk, title,
+                                   dateAdded,
+                                   lastModified,
+                                   syncStatus, syncChangeCounter)
+         SELECT localId, mergedGuid, -1, -1, newType, newPlaceId, newTitle,
+                /* Pick the older of the local and remote date added. We'll
+                   weakly reupload any items with an older local date. */
+                MIN(IFNULL(localDateAddedMicroseconds,
+                           remoteDateAddedMicroseconds),
+                    remoteDateAddedMicroseconds),
+                /* The last modified date should always be newer than the date
+                   added, so we pick the newer of the two here. */
+                MAX(lastModifiedMicroseconds, remoteDateAddedMicroseconds),
+                {syncStatusNormal}, 0
+         FROM itemsToApply
+         WHERE 1
+         ON CONFLICT(id) DO UPDATE SET
+           title = excluded.title,
+           dateAdded = excluded.dateAdded,
+           lastModified = excluded.lastModified,
+           syncStatus = {syncStatusNormal},
+           /* It's important that we update the URL *after* removing old keywords
+              and *before* inserting new ones, so that the above DELETEs select
+              the correct affected items. */
+           fk = excluded.fk",
+        syncStatusNormal = nsINavBookmarksService::SYNC_STATUS_NORMAL
+    ))?;
+    // The roots are never in `itemsToApply` but still need to (well, at least
+    // *should*) have a syncStatus of NORMAL after a reconcilliation. The
+    // ROOT_GUID doesn't matter in practice, but we include it to be consistent.
+    db.exec(format!(
+        "UPDATE moz_bookmarks SET
+            syncStatus={syncStatusNormal}
+         WHERE guid IN {user_roots} OR
+               guid = '{root}'
+               ",
+        syncStatusNormal = nsINavBookmarksService::SYNC_STATUS_NORMAL,
+        root = dogear::ROOT_GUID,
+        user_roots = user_roots_as_sql_set(),
+    ))?;
+
+    // Flag frecencies for recalculation. This is a multi-index OR that uses the
+    // `oldPlacesIds` and `newPlaceIds` partial indexes, since `<>` is only true
+    // if both terms are not NULL. Without those constraints, the subqueries
+    // would scan `itemsToApply` twice. The `oldPlaceId <> newPlaceId` and
+    // `newPlaceId <> oldPlaceId` checks exclude items where the URL didn't
+    // change; we don't need to recalculate their frecencies.
+    debug!(driver, "Flagging frecencies for recalculation");
+    controller.err_if_aborted()?;
+    db.exec(
+        "UPDATE moz_places SET
+           recalc_frecency = 1, recalc_alt_frecency = 1
+         WHERE frecency <> 0 AND (
+           id IN (
+             SELECT oldPlaceId FROM itemsToApply
+             WHERE oldPlaceId <> newPlaceId
+           ) OR id IN (
+             SELECT newPlaceId FROM itemsToApply
+             WHERE newPlaceId <> oldPlaceId
+           )
+         )",
+    )?;
+
+    debug!(driver, "Inserting new keywords for new URLs");
+    controller.err_if_aborted()?;
+    db.exec(
+        "INSERT OR IGNORE INTO moz_keywords(keyword, place_id, post_data)
+         SELECT newKeyword, newPlaceId, ''
+         FROM itemsToApply
+         WHERE newKeyword NOT NULL",
+    )?;
+
+    debug!(driver, "Inserting new tags for new URLs");
+    controller.err_if_aborted()?;
+    db.exec(
+        "INSERT INTO localTags(tag, placeId, lastModifiedMicroseconds)
+         SELECT t.tag, n.newPlaceId, n.lastModifiedMicroseconds
+         FROM itemsToApply n
+         JOIN tags t ON t.itemId = n.remoteId",
+    )?;
+
+    Ok(())
+}
+
+/// Removes deleted local items from Places.
+fn remove_local_items(
+    db: &Conn,
+    driver: &Driver,
+    controller: &AbortController,
+    ops: &[DeleteLocalItem],
+) -> Result<()> {
+    debug!(driver, "Recording observer notifications for removed items");
+    let mut observer_statement = db.prepare(format!(
+        "WITH
+         ops(guid, level) AS (VALUES {})
+         INSERT INTO itemsRemoved(itemId, parentId, position, type, title,
+                                  placeId, guid, parentGuid, level, keywordRemoved)
+         SELECT b.id, b.parent, b.position, b.type, IFNULL(b.title, \"\"), b.fk,
+                b.guid, p.guid, n.level, EXISTS(SELECT 1 FROM moz_keywords k WHERE k.place_id = b.fk)
+         FROM ops n
+         JOIN moz_bookmarks b ON b.guid = n.guid
+         JOIN moz_bookmarks p ON p.id = b.parent",
+        repeat_display(ops.len(), ",", |index, f| {
+            let op = &ops[index];
+            write!(f, "(?, {})", op.local_node().level())
+        }),
+    ))?;
+    for (index, op) in ops.iter().enumerate() {
+        controller.err_if_aborted()?;
+        observer_statement.bind_by_index(
+            index as u32,
+            nsString::from(&*op.local_node().guid.as_str()),
+        )?;
+    }
+    observer_statement.execute()?;
+
+    debug!(driver, "Recalculating frecencies for removed bookmark URLs");
+    let mut frecency_statement = db.prepare(format!(
+        "UPDATE moz_places SET
+            recalc_frecency = 1, recalc_alt_frecency = 1
+         WHERE id IN (SELECT b.fk FROM moz_bookmarks b
+                      WHERE b.guid IN ({})) AND
+               frecency <> 0",
+        repeat_sql_vars(ops.len())
+    ))?;
+    for (index, op) in ops.iter().enumerate() {
+        controller.err_if_aborted()?;
+        frecency_statement.bind_by_index(
+            index as u32,
+            nsString::from(&*op.local_node().guid.as_str()),
+        )?;
+    }
+    frecency_statement.execute()?;
+
+    // This can be removed in bug 1460577.
+    debug!(driver, "Removing annos for deleted items");
+    let mut annos_statement = db.prepare(format!(
+        "DELETE FROM moz_items_annos
+         WHERE item_id = (SELECT b.id FROM moz_bookmarks b
+                          WHERE b.guid IN ({}))",
+        repeat_sql_vars(ops.len()),
+    ))?;
+    for (index, op) in ops.iter().enumerate() {
+        controller.err_if_aborted()?;
+        annos_statement.bind_by_index(
+            index as u32,
+            nsString::from(&*op.local_node().guid.as_str()),
+        )?;
+    }
+    annos_statement.execute()?;
+
+    debug!(
+        driver,
+        "Removing keywords associated with deleted bookmarks"
+    );
+    let mut keywords_statement = db.prepare(format!(
+        "DELETE FROM moz_keywords
+         WHERE place_id IN (SELECT b.fk FROM moz_bookmarks b
+            WHERE b.guid IN ({}))",
+        repeat_sql_vars(ops.len()),
+    ))?;
+    for (index, op) in ops.iter().enumerate() {
+        controller.err_if_aborted()?;
+        keywords_statement.bind_by_index(
+            index as u32,
+            nsString::from(&*op.local_node().guid.as_str()),
+        )?;
+    }
+    keywords_statement.execute()?;
+
+    debug!(driver, "Removing deleted items from Places");
+    let mut delete_statement = db.prepare(format!(
+        "DELETE FROM moz_bookmarks
+         WHERE guid IN ({})",
+        repeat_sql_vars(ops.len()),
+    ))?;
+    for (index, op) in ops.iter().enumerate() {
+        controller.err_if_aborted()?;
+        delete_statement.bind_by_index(
+            index as u32,
+            nsString::from(&*op.local_node().guid.as_str()),
+        )?;
+    }
+    delete_statement.execute()?;
+
+    Ok(())
+}
+
+/// Stores a snapshot of all locally changed items in a temporary table for
+/// upload. This is called from within the merge transaction, to ensure that
+/// changes made during the sync don't cause us to upload inconsistent records.
+///
+/// For an example of why we use a temporary table instead of reading directly
+/// from Places, consider a user adding a bookmark, then changing its parent
+/// folder. We first add the bookmark to the default folder, bump the change
+/// counter of the new bookmark and the default folder, then trigger a sync.
+/// Depending on how quickly the user picks the new parent, we might upload
+/// a record for the default folder, commit the move, then upload the bookmark.
+/// We'll still upload the new parent on the next sync, but, in the meantime,
+/// we've introduced a parent-child disagreement. This can also happen if the
+/// user moves many items between folders.
+///
+/// Conceptually, `itemsToUpload` is a transient "view" of locally changed
+/// items. The change counter in Places is the persistent record of items that
+/// we need to upload, so, if upload is interrupted or fails, we'll stage the
+/// items again on the next sync.
+fn stage_items_to_upload(
+    db: &Conn,
+    driver: &Driver,
+    controller: &AbortController,
+    upload_items: &[UploadItem],
+    upload_tombstones: &[UploadTombstone],
+) -> Result<()> {
+    debug!(driver, "Cleaning up staged items left from last sync");
+    controller.err_if_aborted()?;
+    db.exec("DELETE FROM itemsToUpload")?;
+
+    // Stage remotely changed items with older local creation dates. These are
+    // tracked "weakly": if the upload is interrupted or fails, we won't
+    // reupload the record on the next sync.
+    debug!(driver, "Staging items with older local dates added");
+    controller.err_if_aborted()?;
+    db.exec(format!(
+        "INSERT OR IGNORE INTO itemsToUpload(id, guid, syncChangeCounter,
+                                             parentGuid, parentTitle, dateAdded,
+                                             type, title, placeId, isQuery, url,
+                                             keyword, position, tagFolderName,
+                                             unknownFields)
+         {}
+         JOIN itemsToApply n ON n.mergedGuid = b.guid
+         WHERE n.localDateAddedMicroseconds < n.remoteDateAddedMicroseconds",
+        UploadItemsFragment("b"),
+    ))?;
+
+    debug!(driver, "Staging remaining locally changed items for upload");
+    for chunk in upload_items.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "INSERT OR IGNORE INTO itemsToUpload(id, guid, syncChangeCounter,
+                                                 parentGuid, parentTitle,
+                                                 dateAdded, type, title,
+                                                 placeId, isQuery, url, keyword,
+                                                 position, tagFolderName,
+                                                 unknownFields)
+             {}
+             WHERE b.guid IN ({})",
+            UploadItemsFragment("b"),
+            repeat_sql_vars(chunk.len()),
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(&*op.merged_node.guid))?;
+        }
+        statement.execute()?;
+    }
+
+    // Record the child GUIDs of locally changed folders, which we use to
+    // populate the `children` array in the record.
+    debug!(driver, "Staging structure to upload");
+    controller.err_if_aborted()?;
+    db.exec(
+        "
+        INSERT INTO structureToUpload(guid, parentId, position)
+        SELECT b.guid, b.parent, b.position
+        FROM moz_bookmarks b
+        JOIN itemsToUpload o ON o.id = b.parent",
+    )?;
+
+    // Stage tags for outgoing bookmarks.
+    debug!(driver, "Staging tags to upload");
+    controller.err_if_aborted()?;
+    db.exec(
+        "
+        INSERT OR IGNORE INTO tagsToUpload(id, tag)
+        SELECT o.id, t.tag
+        FROM localTags t
+        JOIN itemsToUpload o ON o.placeId = t.placeId",
+    )?;
+
+    // Finally, stage tombstones for deleted items. Ignore conflicts if we have
+    // tombstones for undeleted items; Places Maintenance should clean these up.
+    debug!(driver, "Staging tombstones to upload");
+    for chunk in upload_tombstones.chunks(db.variable_limit()?) {
+        let mut statement = db.prepare(format!(
+            "INSERT OR IGNORE INTO itemsToUpload(guid, syncChangeCounter, isDeleted)
+             VALUES {}",
+            repeat_display(chunk.len(), ",", |_, f| write!(f, "(?, 1, 1)"))
+        ))?;
+        for (index, op) in chunk.iter().enumerate() {
+            controller.err_if_aborted()?;
+            statement.bind_by_index(index as u32, nsString::from(op.guid().as_str()))?;
+        }
+        statement.execute()?;
+    }
+
+    Ok(())
+}
+
+fn cleanup(db: &Conn) -> Result<()> {
+    db.exec("DELETE FROM itemsToApply")?;
+    Ok(())
+}
+
+/// Formats a list of binding parameters for inclusion in a SQL list.
+#[inline]
+fn repeat_sql_vars(count: usize) -> impl fmt::Display {
+    repeat_display(count, ",", |_, f| write!(f, "?"))
+}
+
+/// Construct a `RepeatDisplay` that will repeatedly call `fmt_one` with a
+/// formatter `count` times, separated by `sep`. This is copied from the
+/// `sql_support` crate in `application-services`.
+#[inline]
+fn repeat_display<'a, F>(count: usize, sep: &'a str, fmt_one: F) -> RepeatDisplay<'a, F>
+where
+    F: Fn(usize, &mut fmt::Formatter) -> fmt::Result,
+{
+    RepeatDisplay {
+        count,
+        sep,
+        fmt_one,
+    }
+}
+
+/// Helper type for printing repeated strings more efficiently.
+#[derive(Debug, Clone)]
+struct RepeatDisplay<'a, F> {
+    count: usize,
+    sep: &'a str,
+    fmt_one: F,
+}
+
+impl<'a, F> fmt::Display for RepeatDisplay<'a, F>
+where
+    F: Fn(usize, &mut fmt::Formatter) -> fmt::Result,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for i in 0..self.count {
+            if i != 0 {
+                f.write_str(self.sep)?;
+            }
+            (self.fmt_one)(i, f)?;
+        }
+        Ok(())
+    }
+}
+
+/// Converts between a type `T` and its SQL representation.
+trait Column<T> {
+    fn from_column(raw: T) -> Result<Self>
+    where
+        Self: Sized;
+    fn into_column(self) -> T;
+}
+
+impl Column<i64> for Kind {
+    fn from_column(raw: i64) -> Result<Kind> {
+        Ok(match i16::try_from(raw) {
+            Ok(mozISyncedBookmarksMerger::KIND_BOOKMARK) => Kind::Bookmark,
+            Ok(mozISyncedBookmarksMerger::KIND_QUERY) => Kind::Query,
+            Ok(mozISyncedBookmarksMerger::KIND_FOLDER) => Kind::Folder,
+            Ok(mozISyncedBookmarksMerger::KIND_LIVEMARK) => Kind::Livemark,
+            Ok(mozISyncedBookmarksMerger::KIND_SEPARATOR) => Kind::Separator,
+            _ => return Err(Error::UnknownItemKind(raw)),
+        })
+    }
+
+    fn into_column(self) -> i64 {
+        match self {
+            Kind::Bookmark => mozISyncedBookmarksMerger::KIND_BOOKMARK as i64,
+            Kind::Query => mozISyncedBookmarksMerger::KIND_QUERY as i64,
+            Kind::Folder => mozISyncedBookmarksMerger::KIND_FOLDER as i64,
+            Kind::Livemark => mozISyncedBookmarksMerger::KIND_LIVEMARK as i64,
+            Kind::Separator => mozISyncedBookmarksMerger::KIND_SEPARATOR as i64,
+        }
+    }
+}
+
+impl Column<i64> for Validity {
+    fn from_column(raw: i64) -> Result<Validity> {
+        Ok(match i16::try_from(raw) {
+            Ok(mozISyncedBookmarksMerger::VALIDITY_VALID) => Validity::Valid,
+            Ok(mozISyncedBookmarksMerger::VALIDITY_REUPLOAD) => Validity::Reupload,
+            Ok(mozISyncedBookmarksMerger::VALIDITY_REPLACE) => Validity::Replace,
+            _ => return Err(Error::UnknownItemValidity(raw).into()),
+        })
+    }
+
+    fn into_column(self) -> i64 {
+        match self {
+            Validity::Valid => mozISyncedBookmarksMerger::VALIDITY_VALID as i64,
+            Validity::Reupload => mozISyncedBookmarksMerger::VALIDITY_REUPLOAD as i64,
+            Validity::Replace => mozISyncedBookmarksMerger::VALIDITY_REPLACE as i64,
+        }
+    }
+}
+
+/// Formats an optional value so that it can be included in a SQL statement.
+struct NullableFragment<T>(Option<T>);
+
+impl<T> fmt::Display for NullableFragment<T>
+where
+    T: fmt::Display,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match &self.0 {
+            Some(v) => v.fmt(f),
+            None => write!(f, "NULL"),
+        }
+    }
+}
+
+/// Formats a `SELECT` statement for staging local items in the `itemsToUpload`
+/// table.
+struct UploadItemsFragment(&'static str);
+
+impl fmt::Display for UploadItemsFragment {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "SELECT {0}.id, {0}.guid, {}.syncChangeCounter,
+                       p.guid AS parentGuid, p.title AS parentTitle,
+                       {0}.dateAdded / 1000 AS dateAdded, {0}.type, {0}.title,
+                       h.id AS placeId,
+                       IFNULL(substr(h.url, 1, 6) = 'place:', 0) AS isQuery,
+                       h.url,
+                       (SELECT keyword FROM moz_keywords WHERE place_id = h.id),
+                       {0}.position,
+                       (SELECT get_query_param(substr(url, 7), 'tag')
+                        WHERE substr(h.url, 1, 6) = 'place:') AS tagFolderName,
+                        v.unknownFields
+                FROM moz_bookmarks {0}
+                JOIN moz_bookmarks p ON p.id = {0}.parent
+                LEFT JOIN moz_places h ON h.id = {0}.fk
+                LEFT JOIN items v ON v.guid = {0}.guid",
+            self.0
+        )
+    }
+}
+
+pub enum ApplyStatus {
+    Merged,
+    Skipped,
+}
+
+impl From<ApplyStatus> for bool {
+    fn from(status: ApplyStatus) -> bool {
+        match status {
+            ApplyStatus::Merged => true,
+            ApplyStatus::Skipped => false,
+        }
+    }
+}
diff --git a/toolkit/components/places/components.conf b/toolkit/components/places/components.conf
new file mode 100644
index 0000000000..af18830a29
--- /dev/null
+++ b/toolkit/components/places/components.conf
@@ -0,0 +1,128 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'name': 'History',
+        'cid': '{0937a705-91a6-417a-8292-b22eb10da86c}',
+        'contract_ids': ['@mozilla.org/browser/history;1'],
+        'singleton': True,
+        'type': 'mozilla::places::History',
+        'headers': ['mozilla/places/History.h'],
+        'constructor': 'mozilla::places::History::GetSingleton',
+    },
+    {
+        'cid': '{e8b8bdb7-c96c-4d82-9c6f-2b3c585ec7ea}',
+        'contract_ids': ['@mozilla.org/network/protocol;1?name=cached-favicon'],
+        'type': 'nsCachedFaviconProtocolHandler',
+        'headers': ['/toolkit/components/places/nsCachedFaviconProtocolHandler.h'],
+        'protocol_config': {
+            'scheme': 'cached-favicon',
+            'flags': [
+                'URI_NORELATIVE',
+                'URI_NOAUTH',
+                'URI_DANGEROUS_TO_LOAD',
+                'URI_IS_LOCAL_RESOURCE',
+            ],
+        },
+    },
+    {
+        'cid': '{984e3259-9266-49cf-b605-60b022a00756}',
+        'contract_ids': ['@mozilla.org/browser/favicon-service;1'],
+        'singleton': True,
+        'type': 'nsFaviconService',
+        'headers': ['/toolkit/components/places/nsFaviconService.h'],
+        'constructor': 'nsFaviconService::GetSingleton',
+    },
+    {
+        'cid': '{9de95a0c-39a4-4d64-9a53-17940dd7cabb}',
+        'contract_ids': ['@mozilla.org/browser/nav-bookmarks-service;1'],
+        'singleton': True,
+        'type': 'nsNavBookmarks',
+        'headers': ['/toolkit/components/places/nsNavBookmarks.h'],
+        'constructor': 'nsNavBookmarks::GetSingleton',
+    },
+    {
+        'cid': '{88cecbb7-6c63-4b3b-8cd4-84f3b8228c69}',
+        'contract_ids': ['@mozilla.org/browser/nav-history-service;1'],
+        'singleton': True,
+        'type': 'nsNavHistory',
+        'headers': ['/toolkit/components/places/nsNavHistory.h'],
+        'constructor': 'nsNavHistory::GetSingleton',
+        'categories': {'vacuum-participant': 'Places'},
+    },
+
+    {
+        'cid': '{bbc23860-2553-479d-8b78-94d9038334f7}',
+        'contract_ids': ['@mozilla.org/browser/tagging-service;1'],
+        'esModule': 'resource://gre/modules/TaggingService.sys.mjs',
+        'constructor': 'TaggingService',
+    },
+    {
+        'cid': '{1dcc23b0-d4cb-11dc-9ad6-479d56d89593}',
+        'contract_ids': ['@mozilla.org/autocomplete/search;1?name=places-tag-autocomplete'],
+        'esModule': 'resource://gre/modules/TaggingService.sys.mjs',
+        'constructor': 'TagAutoCompleteSearch',
+    },
+
+    {
+        'cid': '{705a423f-2f69-42f3-b9fe-1517e0dee56f}',
+        'contract_ids': ['@mozilla.org/places/expiration;1'],
+        'esModule': 'resource://gre/modules/PlacesExpiration.sys.mjs',
+        'constructor': 'nsPlacesExpiration',
+        'categories': {'places-init-complete': 'nsPlacesExpiration'},
+    },
+
+    {
+        'cid': '{d38926e0-29c1-11eb-8588-0800200c9a66}',
+        'contract_ids': ['@mozilla.org/places/databaseUtilsIdleMaintenance;1'],
+        'esModule': 'resource://gre/modules/PlacesDBUtils.sys.mjs',
+        'constructor': 'PlacesDBUtilsIdleMaintenance',
+        'categories': {'idle-daily': 'PlacesDBUtilsIdleMaintenance'},
+    },
+
+    {
+        'cid': '{60a1f7c6-4ff9-4a42-84d3-5a185faa6f32}',
+        'contract_ids': ['@mozilla.org/network/protocol;1?name=page-icon'],
+        'singleton': True,
+        'type': 'mozilla::places::PageIconProtocolHandler',
+        'headers': ['mozilla/places/PageIconProtocolHandler.h'],
+        'constructor': 'mozilla::places::PageIconProtocolHandler::GetSingleton',
+        'protocol_config': {
+            'scheme': 'page-icon',
+            'flags': [
+                'URI_STD',
+                'URI_IS_UI_RESOURCE',
+                'URI_IS_LOCAL_RESOURCE',
+                'URI_NORELATIVE',
+                'URI_NOAUTH',
+            ],
+        },
+    },
+
+    {
+        'cid': '{7d47b41d-7cc5-4882-b293-d8f3f3b48b46}',
+        'contract_ids': ['@mozilla.org/browser/synced-bookmarks-merger;1'],
+        'type': 'mozISyncedBookmarksMerger',
+        'headers': ['mozilla/places/SyncedBookmarksMirror.h'],
+        'constructor': 'mozilla::places::NewSyncedBookmarksMerger',
+    },
+
+    {
+        'cid': '{bd0a4d3b-ff26-4d4d-9a62-a513e1c1bf92}',
+        'contract_ids': ['@mozilla.org/places/previews-helper;1'],
+        'esModule': 'resource://gre/modules/PlacesPreviews.sys.mjs',
+        'constructor': 'PlacesPreviewsHelperService',
+    },
+
+    {
+        'cid': '{1141fd31-4c1a-48eb-8f1a-2f05fad94085}',
+        'contract_ids': ['@mozilla.org/places/frecency-recalculator;1'],
+        'esModule': 'resource://gre/modules/PlacesFrecencyRecalculator.sys.mjs',
+        'constructor': 'PlacesFrecencyRecalculator',
+        'categories': {'places-init-complete': 'PlacesFrecencyRecalculator'},
+    },
+]
diff --git a/toolkit/components/places/moz.build b/toolkit/components/places/moz.build
new file mode 100644
index 0000000000..a0513ec341
--- /dev/null
+++ b/toolkit/components/places/moz.build
@@ -0,0 +1,88 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if CONFIG["MOZ_PLACES"]:
+    TEST_DIRS += ["tests"]
+
+XPIDL_SOURCES += [
+    "nsINavHistoryService.idl",
+]
+
+XPIDL_MODULE = "places"
+
+if CONFIG["MOZ_PLACES"]:
+    XPIDL_SOURCES += [
+        "mozIAsyncHistory.idl",
+        "mozIPlacesAutoComplete.idl",
+        "mozIPlacesPendingOperation.idl",
+        "mozISyncedBookmarksMirror.idl",
+        "nsIFaviconService.idl",
+        "nsINavBookmarksService.idl",
+        "nsIPlacesPreviewsHelperService.idl",
+        "nsITaggingService.idl",
+    ]
+
+    EXPORTS.mozilla.places = [
+        "Database.h",
+        "History.h",
+        "INativePlacesEventCallback.h",
+        "NotifyRankingChanged.h",
+        "PageIconProtocolHandler.h",
+        "Shutdown.h",
+        "SyncedBookmarksMirror.h",
+    ]
+
+    UNIFIED_SOURCES += [
+        "Database.cpp",
+        "FaviconHelpers.cpp",
+        "Helpers.cpp",
+        "History.cpp",
+        "nsCachedFaviconProtocolHandler.cpp",
+        "nsFaviconService.cpp",
+        "nsNavBookmarks.cpp",
+        "nsNavHistory.cpp",
+        "nsNavHistoryQuery.cpp",
+        "nsNavHistoryResult.cpp",
+        "PageIconProtocolHandler.cpp",
+        "PlaceInfo.cpp",
+        "Shutdown.cpp",
+        "SQLFunctions.cpp",
+        "VisitInfo.cpp",
+    ]
+
+    LOCAL_INCLUDES += [
+        "../build",
+    ]
+
+    EXTRA_JS_MODULES += [
+        "BookmarkHTMLUtils.sys.mjs",
+        "BookmarkJSONUtils.sys.mjs",
+        "Bookmarks.sys.mjs",
+        "ExtensionSearchHandler.sys.mjs",
+        "History.sys.mjs",
+        "PlacesBackups.sys.mjs",
+        "PlacesDBUtils.sys.mjs",
+        "PlacesExpiration.sys.mjs",
+        "PlacesFrecencyRecalculator.sys.mjs",
+        "PlacesPreviews.sys.mjs",
+        "PlacesQuery.sys.mjs",
+        "PlacesSyncUtils.sys.mjs",
+        "PlacesTransactions.sys.mjs",
+        "PlacesUtils.sys.mjs",
+        "SyncedBookmarksMirror.sys.mjs",
+        "TaggingService.sys.mjs",
+    ]
+
+    XPCOM_MANIFESTS += [
+        "components.conf",
+    ]
+
+    FINAL_LIBRARY = "xul"
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Places")
diff --git a/toolkit/components/places/mozIAsyncHistory.idl b/toolkit/components/places/mozIAsyncHistory.idl
new file mode 100644
index 0000000000..90c32b1090
--- /dev/null
+++ b/toolkit/components/places/mozIAsyncHistory.idl
@@ -0,0 +1,186 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+interface nsIVariant;
+
+[scriptable, uuid(41e4ccc9-f0c8-4cd7-9753-7a38514b8488)]
+interface mozIVisitInfo : nsISupports
+{
+  /**
+   * The machine-local (internal) id of the visit.
+   */
+  readonly attribute long long visitId;
+
+  /**
+   * The time the visit occurred.
+   */
+  readonly attribute PRTime visitDate;
+
+  /**
+   * The transition type used to get to this visit.  One of the TRANSITION_TYPE
+   * constants on nsINavHistory.
+   *
+   * @see nsINavHistory.idl
+   */
+  readonly attribute unsigned long transitionType;
+
+  /**
+   * The referring URI of this visit.  This may be null.
+   */
+  readonly attribute nsIURI referrerURI;
+};
+
+[scriptable, uuid(ad83e137-c92a-4b7b-b67e-0a318811f91e)]
+interface mozIPlaceInfo : nsISupports
+{
+  /**
+   * The machine-local (internal) id of the place.
+   */
+  readonly attribute long long placeId;
+
+  /**
+   * The globally unique id of the place.
+   */
+  readonly attribute ACString guid;
+
+  /**
+   * The URI of the place.
+   */
+  readonly attribute nsIURI uri;
+
+  /**
+   * The title associated with the place.
+   */
+  readonly attribute AString title;
+
+  /**
+   * The frecency of the place.
+   */
+  readonly attribute long long frecency;
+
+  /**
+   * An array of mozIVisitInfo objects for the place.
+   */
+  [implicit_jscontext]
+  readonly attribute jsval visits;
+};
+
+/**
+ * Shared Callback interface for mozIAsyncHistory methods. The semantics
+ * for each method are detailed in mozIAsyncHistory.
+ */
+[scriptable, uuid(1f266877-2859-418b-a11b-ec3ae4f4f93d)]
+interface mozIVisitInfoCallback : nsISupports
+{
+  /**
+   * Called when the given place could not be processed.
+   *
+   * @param aResultCode
+   *        nsresult indicating the failure reason.
+   * @param aPlaceInfo
+   *        The information that was given to the caller for the place.
+   */
+  void handleError(in nsresult aResultCode,
+                   in mozIPlaceInfo aPlaceInfo);
+
+  /**
+   * Called for each place processed successfully.
+   *
+   * @param aPlaceInfo
+   *        The current info stored for the place.
+   */
+  void handleResult(in mozIPlaceInfo aPlaceInfo);
+
+  /**
+   * Called when all records were processed.
+   * @param aUpdatedItems
+   *        How many items were successfully updated.
+   */
+  void handleCompletion(in unsigned long aUpdatedItems);
+
+  /**
+   * These two attributes govern whether we attempt to call
+   * handleResult and handleError, respectively, if/once
+   * results/errors occur.
+   */
+  readonly attribute bool ignoreResults;
+  readonly attribute bool ignoreErrors;
+};
+
+[scriptable, function, uuid(994092bf-936f-449b-8dd6-0941e024360d)]
+interface mozIVisitedStatusCallback : nsISupports
+{
+  /**
+   * Notifies whether a certain URI has been visited.
+   *
+   * @param aURI
+   *        URI being notified about.
+   * @param aVisitedStatus
+   *        The visited status of aURI.
+   */
+  void isVisited(in nsIURI aURI,
+                 in boolean aVisitedStatus);
+};
+
+/**
+ * This interface contains APIs for cpp consumers.
+ * Javascript consumers should look at History.jsm instead,
+ * that is exposed through PlacesUtils.history.
+ *
+ * If you're evaluating adding a new history API, it should
+ * usually go to History.jsm, unless it needs to do long and
+ * expensive work in a batch, then it could be worth doing
+ * that in History.cpp.
+ */
+
+[scriptable, uuid(1643EFD2-A329-4733-A39D-17069C8D3B2D)]
+interface mozIAsyncHistory : nsISupports
+{
+  /**
+   * Adds a set of visits for one or more mozIPlaceInfo objects, and updates
+   * each mozIPlaceInfo's title or guid.
+   *
+   * aCallback.handleResult is called for each visit added.
+   *
+   * @param aPlaceInfo
+   *        The mozIPlaceInfo object[s] containing the information to store or
+   *        update.  This can be a single object, or an array of objects.
+   * @param [optional] aCallback
+   *        A mozIVisitInfoCallback object which consists of callbacks to be
+   *        notified for successful and/or failed changes.
+   *
+   * @throws NS_ERROR_INVALID_ARG
+   *         - Passing in NULL for aPlaceInfo.
+   *         - Not providing at least one valid guid, or uri for all
+   *           mozIPlaceInfo object[s].
+   *         - Not providing an array or nothing for the visits property of
+   *           mozIPlaceInfo.
+   *         - Not providing a visitDate and transitionType for each
+   *           mozIVisitInfo.
+   *         - Providing an invalid transitionType for a mozIVisitInfo.
+   */
+  [implicit_jscontext]
+  void updatePlaces(in jsval aPlaceInfo,
+                    [optional] in mozIVisitInfoCallback aCallback);
+
+  /**
+   * Checks if a given URI has been visited.
+   *
+   * @param aURI
+   *        The URI to check for.
+   * @param aCallback
+   *        A mozIVisitStatusCallback object which receives the visited status.
+   */
+  void isURIVisited(in nsIURI aURI,
+                    in mozIVisitedStatusCallback aCallback);
+
+  /**
+   * Helper to clear any internal state caches, like the recent URIs list.
+   * This may be useful in testing code.
+   */
+  void clearCache();
+};
diff --git a/toolkit/components/places/mozIPlacesAutoComplete.idl b/toolkit/components/places/mozIPlacesAutoComplete.idl
new file mode 100644
index 0000000000..1b05c55c8f
--- /dev/null
+++ b/toolkit/components/places/mozIPlacesAutoComplete.idl
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+
+/**
+ * This interface provides some constants used by the Places AutoComplete
+ * search provider as well as methods to track opened pages for AutoComplete
+ * purposes.
+ */
+[scriptable, uuid(61b6348a-09e1-4810-8057-f8cb3cec6ef8)]
+interface mozIPlacesAutoComplete : nsISupports
+{
+  //////////////////////////////////////////////////////////////////////////////
+  //// Matching Constants
+
+  // A few of these are not used in Firefox, but are still referenced in
+  // comm-central.
+
+  /**
+   * Match anywhere in each searchable term.
+   */
+  const long MATCH_ANYWHERE = 0;
+
+  /**
+   * Match first on word boundaries, and if we do not get enough results, then
+   * match anywhere in each searchable term.
+   */
+  const long MATCH_BOUNDARY_ANYWHERE = 1;
+
+  /**
+   * Match on word boundaries in each searchable term.
+   */
+  const long MATCH_BOUNDARY = 2;
+
+  /**
+   * Match only the beginning of each search term.
+   */
+  const long MATCH_BEGINNING = 3;
+
+  /**
+   * Match anywhere in each searchable term without doing any transformation
+   * or stripping on the underlying data.
+   */
+  const long MATCH_ANYWHERE_UNMODIFIED = 4;
+
+  /**
+   * Match only the beginning of each search term using a case sensitive
+   * comparator.
+   */
+  const long MATCH_BEGINNING_CASE_SENSITIVE = 5;
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Search Behavior Constants
+
+  /**
+   * Search through history.
+   */
+  const long BEHAVIOR_HISTORY = 1 << 0;
+
+  /**
+   * Search though bookmarks.
+   */
+  const long BEHAVIOR_BOOKMARK = 1 << 1;
+
+  /**
+   * Search through tags.
+   */
+  const long BEHAVIOR_TAG = 1 << 2;
+
+  /**
+   * Search the title of pages.
+   */
+  const long BEHAVIOR_TITLE = 1 << 3;
+
+  /**
+   * Search the URL of pages.
+   */
+  const long BEHAVIOR_URL = 1 << 4;
+
+  /**
+   * Search for typed pages.
+   * No more supported by Firefox, it is still being used by comm-central clients.
+   */
+  const long BEHAVIOR_TYPED = 1 << 5;
+
+  /**
+   * Search javascript: URLs.
+   */
+  const long BEHAVIOR_JAVASCRIPT = 1 << 6;
+
+  /**
+   * Search for pages that have been marked as being opened, such as a tab
+   * in a tabbrowser.
+   */
+  const long BEHAVIOR_OPENPAGE = 1 << 7;
+
+  /**
+   * Use intersection between history, typed, bookmark, tag and openpage
+   * instead of union, when the restrict bit is set.
+   */
+  const long BEHAVIOR_RESTRICT = 1 << 8;
+
+  /**
+   * Include search suggestions from the currently selected search provider.
+   */
+  const long BEHAVIOR_SEARCH = 1 << 9;
+};
diff --git a/toolkit/components/places/mozIPlacesPendingOperation.idl b/toolkit/components/places/mozIPlacesPendingOperation.idl
new file mode 100644
index 0000000000..678a908708
--- /dev/null
+++ b/toolkit/components/places/mozIPlacesPendingOperation.idl
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(ebd31374-3808-40e4-9e73-303bf70467c3)]
+interface mozIPlacesPendingOperation : nsISupports {
+  /**
+   * Cancels a pending operation, if possible.  This will only fail if you try
+   * to cancel more than once.
+   */
+   void cancel();
+};
diff --git a/toolkit/components/places/mozISyncedBookmarksMirror.idl b/toolkit/components/places/mozISyncedBookmarksMirror.idl
new file mode 100644
index 0000000000..0ceaeff5ad
--- /dev/null
+++ b/toolkit/components/places/mozISyncedBookmarksMirror.idl
@@ -0,0 +1,100 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozIServicesLogSink.idl"
+#include "nsISupports.idl"
+
+interface mozIPlacesPendingOperation;
+interface mozIStorageConnection;
+interface nsIPropertyBag;
+
+// A progress listener used to record telemetry.
+[scriptable, uuid(6239ffe3-6ffd-49ac-8b1d-958407395bf9)]
+interface mozISyncedBookmarksMirrorProgressListener : nsISupports {
+  // Called after the merger fetches the local tree from Places, with the time
+  // taken to build the tree, number of items in the tree, and a map of
+  // structure problem counts for validation telemetry.
+  void onFetchLocalTree(in long long took, in long long itemCount,
+                        in long long deletedCount, in nsIPropertyBag problems);
+
+  // Called after the merger builds the remote tree from the mirror database.
+  void onFetchRemoteTree(in long long took, in long long itemCount,
+                         in long long deletedCount, in nsIPropertyBag problems);
+
+  // Called after the merger builds the merged tree, including structure change
+  // counts for event telemetry.
+  void onMerge(in long long took, in nsIPropertyBag counts);
+
+  // Called after the merger finishes applying the merged tree to Places and
+  // staging outgoing items.
+  void onApply(in long long took);
+};
+
+// A callback called when the merge finishes.
+[scriptable, uuid(d23fdfea-92c8-409d-a516-08ae395d578f)]
+interface mozISyncedBookmarksMirrorCallback : nsISupports {
+  void handleSuccess(in bool result);
+  void handleError(in nsresult code, in AString message);
+};
+
+[scriptable, uuid(37485984-a6ab-46e3-9b0c-e8b613413ef3)]
+interface mozISyncedBookmarksMirrorLogger : nsISupports {
+  const short LEVEL_OFF = 0;
+  const short LEVEL_ERROR = 1;
+  const short LEVEL_WARN = 2;
+  const short LEVEL_DEBUG = 3;
+  const short LEVEL_TRACE = 4;
+
+  attribute short maxLevel;
+
+  void error(in AString message);
+  void warn(in AString message);
+  void debug(in AString message);
+  void trace(in AString message);
+};
+
+[scriptable, builtinclass, uuid(f0a6217d-8344-4e68-9995-bbf5554be86e)]
+interface mozISyncedBookmarksMerger : nsISupports {
+  // Synced item kinds. These are stored in the mirror database.
+  const short KIND_BOOKMARK = 1;
+  const short KIND_QUERY = 2;
+  const short KIND_FOLDER = 3;
+  const short KIND_LIVEMARK = 4;
+  const short KIND_SEPARATOR = 5;
+
+  // Synced item validity states. These are also stored in the mirror
+  // database. `REUPLOAD` means a remote item can be fixed up and applied,
+  // and should be reuploaded. `REPLACE` means a remote item isn't valid
+  // at all, and should either be replaced with a valid local copy, or deleted
+  // if a valid local copy doesn't exist.
+  const short VALIDITY_VALID = 1;
+  const short VALIDITY_REUPLOAD = 2;
+  const short VALIDITY_REPLACE = 3;
+
+  // The mirror database connection to use for merging. The merge runs on the
+  // connection's async thread, to avoid blocking the main thread. The
+  // connection must be open, and the database schema, temp tables, and
+  // triggers must be set up before calling `merge`.
+  attribute mozIStorageConnection db;
+
+  // Optional; used for logging.
+  attribute mozIServicesLogSink logger;
+
+  // Merges the local and remote bookmark trees, applies the merged tree to
+  // Places, and stages locally changed and reconciled items for upload. When
+  // the merge finishes, either `callback.handleSuccess` or
+  // `callback.handleError` are called. If `callback` also implements
+  // `mozISyncedBookmarksMergerProgressListener`, the merger reports progress
+  // after each step. Returns an object with a `cancel` method that can be used
+  // to interrupt the merge.
+  mozIPlacesPendingOperation merge(
+    in long long localTimeSeconds,
+    in long long remoteTimeSeconds,
+    in mozISyncedBookmarksMirrorCallback callback
+  );
+
+  // Resets the database connection and logger. This does _not_ automatically
+  // close the database connection.
+  void reset();
+};
diff --git a/toolkit/components/places/nsCachedFaviconProtocolHandler.cpp b/toolkit/components/places/nsCachedFaviconProtocolHandler.cpp
new file mode 100644
index 0000000000..9688c4ce08
--- /dev/null
+++ b/toolkit/components/places/nsCachedFaviconProtocolHandler.cpp
@@ -0,0 +1,341 @@
+//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Implementation of cached-favicon: URLs for accessing favicons. The urls are
+ * sent to the favicon service. If the favicon service doesn't have the data,
+ * a stream containing the default favicon will be returned.
+ */
+
+#include "nsCachedFaviconProtocolHandler.h"
+#include "nsFaviconService.h"
+#include "nsICancelable.h"
+#include "nsIChannel.h"
+#include "nsIInputStream.h"
+#include "nsISupportsUtils.h"
+#include "nsIURI.h"
+#include "nsNetUtil.h"
+#include "nsInputStreamPump.h"
+#include "nsContentUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsStringStream.h"
+#include "SimpleChannel.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/storage.h"
+#include "mozIStorageResultSet.h"
+#include "mozIStorageRow.h"
+#include "Helpers.h"
+#include "FaviconHelpers.h"
+
+using namespace mozilla;
+using namespace mozilla::places;
+
+////////////////////////////////////////////////////////////////////////////////
+//// Global Functions
+
+/**
+ * Creates a channel to obtain the default favicon.
+ */
+static nsresult GetDefaultIcon(nsIChannel* aOriginalChannel,
+                               nsIChannel** aChannel) {
+  nsCOMPtr<nsIURI> defaultIconURI;
+  nsresult rv = NS_NewURI(getter_AddRefs(defaultIconURI),
+                          nsLiteralCString(FAVICON_DEFAULT_URL));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsILoadInfo> loadInfo = aOriginalChannel->LoadInfo();
+  rv = NS_NewChannelInternal(aChannel, defaultIconURI, loadInfo);
+  NS_ENSURE_SUCCESS(rv, rv);
+  Unused << (*aChannel)->SetContentType(
+      nsLiteralCString(FAVICON_DEFAULT_MIMETYPE));
+  Unused << aOriginalChannel->SetContentType(
+      nsLiteralCString(FAVICON_DEFAULT_MIMETYPE));
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// faviconAsyncLoader
+
+namespace {
+
+/**
+ * An instance of this class is passed to the favicon service as the callback
+ * for getting favicon data from the database.  We'll get this data back in
+ * HandleResult, and on HandleCompletion, we'll close our output stream which
+ * will close the original channel for the favicon request.
+ *
+ * However, if an error occurs at any point and we don't have mData, we will
+ * just fallback to the default favicon.  If anything happens at that point, the
+ * world must be against us, so we can do nothing.
+ */
+class faviconAsyncLoader : public AsyncStatementCallback, public nsICancelable {
+  NS_DECL_NSICANCELABLE
+  NS_DECL_ISUPPORTS_INHERITED
+
+ public:
+  faviconAsyncLoader(nsIChannel* aChannel, nsIStreamListener* aListener,
+                     uint16_t aPreferredSize)
+      : mChannel(aChannel),
+        mListener(aListener),
+        mPreferredSize(aPreferredSize) {
+    MOZ_ASSERT(aChannel, "Not providing a channel will result in crashes!");
+    MOZ_ASSERT(aListener,
+               "Not providing a stream listener will result in crashes!");
+    MOZ_ASSERT(aChannel, "Not providing a channel!");
+  }
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// mozIStorageStatementCallback
+
+  NS_IMETHOD HandleResult(mozIStorageResultSet* aResultSet) override {
+    nsCOMPtr<mozIStorageRow> row;
+    while (NS_SUCCEEDED(aResultSet->GetNextRow(getter_AddRefs(row))) && row) {
+      int32_t width;
+      nsresult rv = row->GetInt32(1, &width);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // Check if we already found an image >= than the preferred size,
+      // otherwise keep examining the next results.
+      if (width < mPreferredSize && !mData.IsEmpty()) {
+        return NS_OK;
+      }
+
+      // Eventually override the default mimeType for svg.
+      if (width == UINT16_MAX) {
+        rv = mChannel->SetContentType(nsLiteralCString(SVG_MIME_TYPE));
+      } else {
+        rv = mChannel->SetContentType(nsLiteralCString(PNG_MIME_TYPE));
+      }
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // Obtain the binary blob that contains our favicon data.
+      uint8_t* data;
+      uint32_t dataLen;
+      rv = row->GetBlob(0, &dataLen, &data);
+      NS_ENSURE_SUCCESS(rv, rv);
+      mData.Adopt(TO_CHARBUFFER(data), dataLen);
+    }
+
+    return NS_OK;
+  }
+
+  static void CancelRequest(nsIStreamListener* aListener, nsIChannel* aChannel,
+                            nsresult aResult) {
+    MOZ_ASSERT(aListener);
+    MOZ_ASSERT(aChannel);
+
+    aListener->OnStartRequest(aChannel);
+    aListener->OnStopRequest(aChannel, aResult);
+    aChannel->CancelWithReason(NS_BINDING_ABORTED,
+                               "faviconAsyncLoader::CancelRequest"_ns);
+  }
+
+  NS_IMETHOD HandleCompletion(uint16_t aReason) override {
+    MOZ_DIAGNOSTIC_ASSERT(mListener);
+    MOZ_ASSERT(mChannel);
+    NS_ENSURE_TRUE(mListener, NS_ERROR_UNEXPECTED);
+    NS_ENSURE_TRUE(mChannel, NS_ERROR_UNEXPECTED);
+
+    // Ensure we'll break possible cycles with the listener.
+    auto cleanup = MakeScopeExit([&]() {
+      mListener = nullptr;
+      mChannel = nullptr;
+    });
+
+    if (mCanceled) {
+      // The channel that has created this faviconAsyncLoader has been canceled.
+      CancelRequest(mListener, mChannel, mStatus);
+      return NS_OK;
+    }
+
+    nsresult rv;
+
+    nsCOMPtr<nsILoadInfo> loadInfo = mChannel->LoadInfo();
+    nsISerialEventTarget* target = GetMainThreadSerialEventTarget();
+    if (!mData.IsEmpty()) {
+      nsCOMPtr<nsIInputStream> stream;
+      rv = NS_NewCStringInputStream(getter_AddRefs(stream), mData);
+      MOZ_ASSERT(NS_SUCCEEDED(rv));
+      if (NS_SUCCEEDED(rv)) {
+        RefPtr<nsInputStreamPump> pump;
+        rv = nsInputStreamPump::Create(getter_AddRefs(pump), stream, 0, 0, true,
+                                       target);
+        MOZ_ASSERT(NS_SUCCEEDED(rv));
+        if (NS_SUCCEEDED(rv)) {
+          rv = pump->AsyncRead(mListener);
+          if (NS_FAILED(rv)) {
+            CancelRequest(mListener, mChannel, rv);
+            return rv;
+          }
+
+          mPump = pump;
+          return NS_OK;
+        }
+      }
+    }
+
+    // Fallback to the default favicon.
+    // we should pass the loadInfo of the original channel along
+    // to the new channel. Note that mChannel can not be null,
+    // constructor checks that.
+    rv = GetDefaultIcon(mChannel, getter_AddRefs(mDefaultIconChannel));
+    if (NS_FAILED(rv)) {
+      CancelRequest(mListener, mChannel, rv);
+      return rv;
+    }
+
+    rv = mDefaultIconChannel->AsyncOpen(mListener);
+    if (NS_FAILED(rv)) {
+      mDefaultIconChannel = nullptr;
+      CancelRequest(mListener, mChannel, rv);
+      return rv;
+    }
+
+    return NS_OK;
+  }
+
+ protected:
+  virtual ~faviconAsyncLoader() = default;
+
+ private:
+  nsCOMPtr<nsIChannel> mChannel;
+  nsCOMPtr<nsIChannel> mDefaultIconChannel;
+  nsCOMPtr<nsIStreamListener> mListener;
+  nsCOMPtr<nsIInputStreamPump> mPump;
+  nsCString mData;
+  uint16_t mPreferredSize;
+  bool mCanceled{false};
+  nsresult mStatus{NS_OK};
+};
+
+NS_IMPL_ISUPPORTS_INHERITED(faviconAsyncLoader, AsyncStatementCallback,
+                            nsICancelable)
+
+NS_IMETHODIMP
+faviconAsyncLoader::Cancel(nsresult aStatus) {
+  if (mCanceled) {
+    return NS_OK;
+  }
+
+  mCanceled = true;
+  mStatus = aStatus;
+
+  if (mPump) {
+    mPump->Cancel(aStatus);
+    mPump = nullptr;
+  }
+
+  if (mDefaultIconChannel) {
+    mDefaultIconChannel->Cancel(aStatus);
+    mDefaultIconChannel = nullptr;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsCachedFaviconProtocolHandler
+
+NS_IMPL_ISUPPORTS(nsCachedFaviconProtocolHandler, nsIProtocolHandler)
+
+// nsCachedFaviconProtocolHandler::GetScheme
+
+NS_IMETHODIMP
+nsCachedFaviconProtocolHandler::GetScheme(nsACString& aScheme) {
+  aScheme.AssignLiteral("cached-favicon");
+  return NS_OK;
+}
+
+// nsCachedFaviconProtocolHandler::NewChannel
+//
+
+NS_IMETHODIMP
+nsCachedFaviconProtocolHandler::NewChannel(nsIURI* aURI, nsILoadInfo* aLoadInfo,
+                                           nsIChannel** _retval) {
+  NS_ENSURE_ARG_POINTER(aURI);
+
+  nsCOMPtr<nsIURI> cachedFaviconURI;
+  nsresult rv = ParseCachedFaviconURI(aURI, getter_AddRefs(cachedFaviconURI));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NewFaviconChannel(aURI, cachedFaviconURI, aLoadInfo, _retval);
+}
+
+// nsCachedFaviconProtocolHandler::AllowPort
+//
+//    Don't override any bans on bad ports.
+
+NS_IMETHODIMP
+nsCachedFaviconProtocolHandler::AllowPort(int32_t port, const char* scheme,
+                                          bool* _retval) {
+  *_retval = false;
+  return NS_OK;
+}
+
+// nsCachedFaviconProtocolHandler::ParseCachedFaviconURI
+//
+//    Get actual URI from cached-favicon URL
+
+nsresult nsCachedFaviconProtocolHandler::ParseCachedFaviconURI(
+    nsIURI* aURI, nsIURI** aResultURI) {
+  nsresult rv;
+  nsAutoCString path;
+  rv = aURI->GetPathQueryRef(path);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = NS_NewURI(aResultURI, path);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+nsresult nsCachedFaviconProtocolHandler::NewFaviconChannel(
+    nsIURI* aURI, nsIURI* aCachedFaviconURI, nsILoadInfo* aLoadInfo,
+    nsIChannel** _channel) {
+  // Create our channel.  We'll call SetContentType with the right type when
+  // we know what it actually is.
+  nsCOMPtr<nsIChannel> channel = NS_NewSimpleChannel(
+      aURI, aLoadInfo, aCachedFaviconURI,
+      [](nsIStreamListener* listener, nsIChannel* channel,
+         nsIURI* cachedFaviconURI) -> RequestOrReason {
+        auto fallback = [&]() -> RequestOrReason {
+          nsCOMPtr<nsIChannel> chan;
+          nsresult rv = GetDefaultIcon(channel, getter_AddRefs(chan));
+          NS_ENSURE_SUCCESS(rv, Err(rv));
+
+          rv = chan->AsyncOpen(listener);
+          NS_ENSURE_SUCCESS(rv, Err(rv));
+
+          nsCOMPtr<nsIRequest> request(chan);
+          return RequestOrCancelable(WrapNotNull(request));
+        };
+
+        // Now we go ahead and get our data asynchronously for the favicon.
+        // Ignore the ref part of the URI before querying the database because
+        // we may have added a size fragment for rendering purposes.
+        nsFaviconService* faviconService =
+            nsFaviconService::GetFaviconService();
+        nsAutoCString faviconSpec;
+        nsresult rv = cachedFaviconURI->GetSpecIgnoringRef(faviconSpec);
+        // Any failures fallback to the default icon channel.
+        if (NS_FAILED(rv) || !faviconService) return fallback();
+
+        uint16_t preferredSize = UINT16_MAX;
+        MOZ_ALWAYS_SUCCEEDS(faviconService->PreferredSizeFromURI(
+            cachedFaviconURI, &preferredSize));
+        nsCOMPtr<mozIStorageStatementCallback> callback =
+            new faviconAsyncLoader(channel, listener, preferredSize);
+        if (!callback) return fallback();
+
+        rv = faviconService->GetFaviconDataAsync(faviconSpec, callback);
+        if (NS_FAILED(rv)) return fallback();
+
+        nsCOMPtr<nsICancelable> cancelable = do_QueryInterface(callback);
+        return RequestOrCancelable(WrapNotNull(cancelable));
+      });
+  NS_ENSURE_TRUE(channel, NS_ERROR_OUT_OF_MEMORY);
+
+  channel.forget(_channel);
+  return NS_OK;
+}
diff --git a/toolkit/components/places/nsCachedFaviconProtocolHandler.h b/toolkit/components/places/nsCachedFaviconProtocolHandler.h
new file mode 100644
index 0000000000..b252f63596
--- /dev/null
+++ b/toolkit/components/places/nsCachedFaviconProtocolHandler.h
@@ -0,0 +1,55 @@
+//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCachedFaviconProtocolHandler_h___
+#define nsCachedFaviconProtocolHandler_h___
+
+#include "nsCOMPtr.h"
+#include "nsIProtocolHandler.h"
+#include "nsIURI.h"
+#include "nsString.h"
+#include "nsWeakReference.h"
+#include "mozilla/Attributes.h"
+
+// {e8b8bdb7-c96c-4d82-9c6f-2b3c585ec7ea}
+#define NS_CACHEDFAVICONPROTOCOLHANDLER_CID          \
+  {                                                  \
+    0xe8b8bdb7, 0xc96c, 0x4d82, {                    \
+      0x9c, 0x6f, 0x2b, 0x3c, 0x58, 0x5e, 0xc7, 0xea \
+    }                                                \
+  }
+
+class nsCachedFaviconProtocolHandler final : public nsIProtocolHandler,
+                                             public nsSupportsWeakReference {
+ public:
+  nsCachedFaviconProtocolHandler() = default;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPROTOCOLHANDLER
+
+ private:
+  ~nsCachedFaviconProtocolHandler() = default;
+
+  nsresult ParseCachedFaviconURI(nsIURI* aURI, nsIURI** aResultURI);
+
+  /**
+   * Obtains a new channel to be used to get a favicon from the database.  This
+   * method is asynchronous.
+   *
+   * @param aURI
+   *        The URI the channel will be created for.  This is the URI that is
+   *        set as the original URI on the channel.
+   * @param aCachedFaviconURI
+   *        The URI that holds the data needed to get the favicon from the
+   *        database.
+   * @param aLoadInfo
+   *        The loadinfo that requested the resource load.
+   * @returns (via _channel) the channel that will obtain the favicon data.
+   */
+  nsresult NewFaviconChannel(nsIURI* aURI, nsIURI* aCachedFaviconURI,
+                             nsILoadInfo* aLoadInfo, nsIChannel** _channel);
+};
+
+#endif /* nsCachedFaviconProtocolHandler_h___ */
diff --git a/toolkit/components/places/nsFaviconService.cpp b/toolkit/components/places/nsFaviconService.cpp
new file mode 100644
index 0000000000..51d20236c3
--- /dev/null
+++ b/toolkit/components/places/nsFaviconService.cpp
@@ -0,0 +1,862 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This is the favicon service, which stores favicons for web pages with your
+ * history as you browse. It is also used to save the favicons for bookmarks.
+ *
+ * DANGER: The history query system makes assumptions about the favicon storage
+ * so that icons can be quickly generated for history/bookmark result sets. If
+ * you change the database layout at all, you will have to update both services.
+ */
+
+#include "nsFaviconService.h"
+
+#include "nsNavHistory.h"
+#include "nsPlacesMacros.h"
+#include "Helpers.h"
+
+#include "nsNetUtil.h"
+#include "nsReadableUtils.h"
+#include "nsStreamUtils.h"
+#include "plbase64.h"
+#include "nsIClassInfoImpl.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/LoadInfo.h"
+#include "mozilla/NullPrincipal.h"
+#include "mozilla/Preferences.h"
+#include "nsILoadInfo.h"
+#include "nsIContentPolicy.h"
+#include "nsIProtocolHandler.h"
+#include "nsIScriptError.h"
+#include "nsContentUtils.h"
+#include "imgICache.h"
+
+#define UNASSOCIATED_FAVICONS_LENGTH 32
+
+// When replaceFaviconData is called, we store the icons in an in-memory cache
+// instead of in storage. Icons in the cache are expired according to this
+// interval.
+#define UNASSOCIATED_ICON_EXPIRY_INTERVAL 60000
+
+using namespace mozilla;
+using namespace mozilla::places;
+
+const uint16_t gFaviconSizes[7] = {192, 144, 96, 64, 48, 32, 16};
+
+/**
+ * Used to notify a topic to system observers on async execute completion.
+ * Will throw on error.
+ */
+class ExpireFaviconsStatementCallbackNotifier : public AsyncStatementCallback {
+ public:
+  ExpireFaviconsStatementCallbackNotifier();
+  NS_IMETHOD HandleCompletion(uint16_t aReason) override;
+};
+
+namespace {
+
+/**
+ * Extracts and filters native sizes from the given container, based on the
+ * list of sizes we are supposed to retain.
+ * All calculation is done considering square sizes and the largest side.
+ * In case of multiple frames of the same size, only the first one is retained.
+ */
+nsresult GetFramesInfoForContainer(imgIContainer* aContainer,
+                                   nsTArray<FrameData>& aFramesInfo) {
+  // Don't extract frames from animated images.
+  bool animated;
+  nsresult rv = aContainer->GetAnimated(&animated);
+  if (NS_FAILED(rv) || !animated) {
+    nsTArray<nsIntSize> nativeSizes;
+    rv = aContainer->GetNativeSizes(nativeSizes);
+    if (NS_SUCCEEDED(rv) && nativeSizes.Length() > 1) {
+      for (uint32_t i = 0; i < nativeSizes.Length(); ++i) {
+        nsIntSize nativeSize = nativeSizes[i];
+        // Only retain square frames.
+        if (nativeSize.width != nativeSize.height) {
+          continue;
+        }
+        // Check if it's one of the sizes we care about.
+        const auto* end = std::end(gFaviconSizes);
+        const uint16_t* matchingSize =
+            std::find(std::begin(gFaviconSizes), end, nativeSize.width);
+        if (matchingSize != end) {
+          // We must avoid duped sizes, an image could contain multiple frames
+          // of the same size, but we can only store one. We could use an
+          // hashtable, but considered the average low number of frames, we'll
+          // just do a linear search.
+          bool dupe = false;
+          for (const auto& frameInfo : aFramesInfo) {
+            if (frameInfo.width == *matchingSize) {
+              dupe = true;
+              break;
+            }
+          }
+          if (!dupe) {
+            aFramesInfo.AppendElement(FrameData(i, *matchingSize));
+          }
+        }
+      }
+    }
+  }
+
+  if (aFramesInfo.Length() == 0) {
+    // Always have at least the default size.
+    int32_t width;
+    rv = aContainer->GetWidth(&width);
+    NS_ENSURE_SUCCESS(rv, rv);
+    int32_t height;
+    rv = aContainer->GetHeight(&height);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // For non-square images, pick the largest side.
+    aFramesInfo.AppendElement(FrameData(0, std::max(width, height)));
+  }
+  return NS_OK;
+}
+
+}  // namespace
+
+PLACES_FACTORY_SINGLETON_IMPLEMENTATION(nsFaviconService, gFaviconService)
+
+NS_IMPL_CLASSINFO(nsFaviconService, nullptr, 0, NS_FAVICONSERVICE_CID)
+NS_IMPL_ISUPPORTS_CI(nsFaviconService, nsIFaviconService, nsITimerCallback,
+                     nsINamed)
+
+nsFaviconService::nsFaviconService()
+    : mUnassociatedIcons(UNASSOCIATED_FAVICONS_LENGTH),
+      mDefaultIconURIPreferredSize(UINT16_MAX) {
+  NS_ASSERTION(!gFaviconService,
+               "Attempting to create two instances of the service!");
+  gFaviconService = this;
+}
+
+nsFaviconService::~nsFaviconService() {
+  NS_ASSERTION(gFaviconService == this,
+               "Deleting a non-singleton instance of the service");
+  if (gFaviconService == this) gFaviconService = nullptr;
+}
+
+Atomic<int64_t> nsFaviconService::sLastInsertedIconId(0);
+
+void  // static
+nsFaviconService::StoreLastInsertedId(const nsACString& aTable,
+                                      const int64_t aLastInsertedId) {
+  MOZ_ASSERT(aTable.EqualsLiteral("moz_icons"));
+  sLastInsertedIconId = aLastInsertedId;
+}
+
+nsresult nsFaviconService::Init() {
+  mDB = Database::GetDatabase();
+  NS_ENSURE_STATE(mDB);
+
+  mExpireUnassociatedIconsTimer = NS_NewTimer();
+  NS_ENSURE_STATE(mExpireUnassociatedIconsTimer);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::ExpireAllFavicons() {
+  NS_ENSURE_STATE(mDB);
+
+  nsCOMPtr<mozIStorageAsyncStatement> removePagesStmt =
+      mDB->GetAsyncStatement("DELETE FROM moz_pages_w_icons");
+  NS_ENSURE_STATE(removePagesStmt);
+  nsCOMPtr<mozIStorageAsyncStatement> removeIconsStmt =
+      mDB->GetAsyncStatement("DELETE FROM moz_icons");
+  NS_ENSURE_STATE(removeIconsStmt);
+  nsCOMPtr<mozIStorageAsyncStatement> unlinkIconsStmt =
+      mDB->GetAsyncStatement("DELETE FROM moz_icons_to_pages");
+  NS_ENSURE_STATE(unlinkIconsStmt);
+
+  nsTArray<RefPtr<mozIStorageBaseStatement>> stmts = {
+      ToRefPtr(std::move(removePagesStmt)),
+      ToRefPtr(std::move(removeIconsStmt)),
+      ToRefPtr(std::move(unlinkIconsStmt))};
+  nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
+  if (!conn) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  nsCOMPtr<mozIStoragePendingStatement> ps;
+  RefPtr<ExpireFaviconsStatementCallbackNotifier> callback =
+      new ExpireFaviconsStatementCallbackNotifier();
+  return conn->ExecuteAsync(stmts, callback, getter_AddRefs(ps));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsITimerCallback
+
+NS_IMETHODIMP
+nsFaviconService::Notify(nsITimer* timer) {
+  if (timer != mExpireUnassociatedIconsTimer.get()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  PRTime now = PR_Now();
+  for (auto iter = mUnassociatedIcons.Iter(); !iter.Done(); iter.Next()) {
+    UnassociatedIconHashKey* iconKey = iter.Get();
+    if (now - iconKey->created >= UNASSOCIATED_ICON_EXPIRY_INTERVAL) {
+      iter.Remove();
+    }
+  }
+
+  // Re-init the expiry timer if the cache isn't empty.
+  if (mUnassociatedIcons.Count() > 0) {
+    mExpireUnassociatedIconsTimer->InitWithCallback(
+        this, UNASSOCIATED_ICON_EXPIRY_INTERVAL, nsITimer::TYPE_ONE_SHOT);
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////
+//// nsINamed
+
+NS_IMETHODIMP
+nsFaviconService::GetName(nsACString& aName) {
+  aName.AssignLiteral("nsFaviconService");
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIFaviconService
+
+NS_IMETHODIMP
+nsFaviconService::GetDefaultFavicon(nsIURI** _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  // not found, use default
+  if (!mDefaultIcon) {
+    nsresult rv = NS_NewURI(getter_AddRefs(mDefaultIcon),
+                            nsLiteralCString(FAVICON_DEFAULT_URL));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsCOMPtr<nsIURI> uri = mDefaultIcon;
+  uri.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::GetDefaultFaviconMimeType(nsACString& _retval) {
+  _retval = nsLiteralCString(FAVICON_DEFAULT_MIMETYPE);
+  return NS_OK;
+}
+
+void nsFaviconService::ClearImageCache(nsIURI* aImageURI) {
+  MOZ_ASSERT(aImageURI, "Must pass a non-null URI");
+  nsCOMPtr<imgICache> imgCache;
+  nsresult rv =
+      GetImgTools()->GetImgCacheForDocument(nullptr, getter_AddRefs(imgCache));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  if (NS_SUCCEEDED(rv)) {
+    Unused << imgCache->RemoveEntry(aImageURI, nullptr);
+  }
+}
+
+NS_IMETHODIMP
+nsFaviconService::SetAndFetchFaviconForPage(
+    nsIURI* aPageURI, nsIURI* aFaviconURI, bool aForceReload,
+    uint32_t aFaviconLoadType, nsIFaviconDataCallback* aCallback,
+    nsIPrincipal* aLoadingPrincipal, uint64_t aRequestContextID,
+    mozIPlacesPendingOperation** _canceler) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aPageURI);
+  NS_ENSURE_ARG(aFaviconURI);
+  NS_ENSURE_ARG_POINTER(_canceler);
+
+  nsCOMPtr<nsIPrincipal> loadingPrincipal = aLoadingPrincipal;
+  MOZ_ASSERT(loadingPrincipal,
+             "please provide aLoadingPrincipal for this favicon");
+  if (!loadingPrincipal) {
+    // Let's default to the nullPrincipal if no loadingPrincipal is provided.
+    AutoTArray<nsString, 2> params = {
+        u"nsFaviconService::setAndFetchFaviconForPage()"_ns,
+        u"nsFaviconService::setAndFetchFaviconForPage(..., "
+        "[optional aLoadingPrincipal])"_ns};
+    nsContentUtils::ReportToConsole(
+        nsIScriptError::warningFlag, "Security by Default"_ns,
+        nullptr,  // aDocument
+        nsContentUtils::eNECKO_PROPERTIES, "APIDeprecationWarning", params);
+    loadingPrincipal = NullPrincipal::CreateWithoutOriginAttributes();
+  }
+  NS_ENSURE_TRUE(loadingPrincipal, NS_ERROR_FAILURE);
+
+  bool loadPrivate =
+      aFaviconLoadType == nsIFaviconService::FAVICON_LOAD_PRIVATE;
+
+  // Build page data.
+  PageData page;
+  nsresult rv = aPageURI->GetSpec(page.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // URIs can arguably lack a host.
+  Unused << aPageURI->GetHost(page.host);
+  if (StringBeginsWith(page.host, "www."_ns)) {
+    page.host.Cut(0, 4);
+  }
+  bool canAddToHistory;
+  nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(navHistory, NS_ERROR_OUT_OF_MEMORY);
+  rv = navHistory->CanAddURI(aPageURI, &canAddToHistory);
+  NS_ENSURE_SUCCESS(rv, rv);
+  page.canAddToHistory = !!canAddToHistory && !loadPrivate;
+
+  // Build icon data.
+  IconData icon;
+  // If we have an in-memory icon payload, it overwrites the actual request.
+  UnassociatedIconHashKey* iconKey = mUnassociatedIcons.GetEntry(aFaviconURI);
+  if (iconKey) {
+    icon = iconKey->iconData;
+    mUnassociatedIcons.RemoveEntry(iconKey);
+  } else {
+    icon.fetchMode = aForceReload ? FETCH_ALWAYS : FETCH_IF_MISSING;
+    rv = aFaviconURI->GetSpec(icon.spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // URIs can arguably lack a host.
+    Unused << aFaviconURI->GetHost(icon.host);
+    if (StringBeginsWith(icon.host, "www."_ns)) {
+      icon.host.Cut(0, 4);
+    }
+  }
+
+  // A root icon is when the icon and page have the same host and the path
+  // is just /favicon.ico. These icons are considered valid for the whole
+  // origin and expired with the origin through a trigger.
+  nsAutoCString path;
+  if (NS_SUCCEEDED(aFaviconURI->GetPathQueryRef(path)) &&
+      !icon.host.IsEmpty() && icon.host.Equals(page.host) &&
+      path.EqualsLiteral("/favicon.ico")) {
+    icon.rootIcon = 1;
+  }
+
+  // If the page url points to an image, the icon's url will be the same.
+  // TODO (Bug 403651): store a resample of the image.  For now avoid that
+  // for database size and UX concerns.
+  // Don't store favicons for error pages either.
+  if (icon.spec.Equals(page.spec) ||
+      icon.spec.EqualsLiteral(FAVICON_CERTERRORPAGE_URL) ||
+      icon.spec.EqualsLiteral(FAVICON_ERRORPAGE_URL)) {
+    return NS_OK;
+  }
+
+  RefPtr<AsyncFetchAndSetIconForPage> event = new AsyncFetchAndSetIconForPage(
+      icon, page, loadPrivate, aCallback, aLoadingPrincipal, aRequestContextID);
+
+  // Get the target thread and start the work.
+  // DB will be updated and observers notified when data has finished loading.
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  DB->DispatchToAsyncThread(event);
+
+  // Return this event to the caller to allow aborting an eventual fetch.
+  event.forget(_canceler);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::ReplaceFaviconData(nsIURI* aFaviconURI,
+                                     const nsTArray<uint8_t>& aData,
+                                     const nsACString& aMimeType,
+                                     PRTime aExpiration) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aFaviconURI);
+  NS_ENSURE_ARG(aData.Length() > 0);
+  NS_ENSURE_ARG(aMimeType.Length() > 0);
+  NS_ENSURE_ARG(imgLoader::SupportImageWithMimeType(
+      aMimeType, AcceptedMimeTypes::IMAGES_AND_DOCUMENTS));
+
+  PRTime now = PR_Now();
+  if (aExpiration < now + MIN_FAVICON_EXPIRATION) {
+    // Invalid input, just use the default.
+    aExpiration = now + MAX_FAVICON_EXPIRATION;
+  }
+
+  UnassociatedIconHashKey* iconKey = mUnassociatedIcons.PutEntry(aFaviconURI);
+  if (!iconKey) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  iconKey->created = now;
+
+  // If the cache contains unassociated icons, an expiry timer should already
+  // exist, otherwise there may be a timer left hanging around, so make sure we
+  // fire a new one.
+  uint32_t unassociatedCount = mUnassociatedIcons.Count();
+  if (unassociatedCount == 1) {
+    mExpireUnassociatedIconsTimer->Cancel();
+    mExpireUnassociatedIconsTimer->InitWithCallback(
+        this, UNASSOCIATED_ICON_EXPIRY_INTERVAL, nsITimer::TYPE_ONE_SHOT);
+  }
+
+  IconData* iconData = &(iconKey->iconData);
+  iconData->expiration = aExpiration;
+  iconData->status = ICON_STATUS_CACHED;
+  iconData->fetchMode = FETCH_NEVER;
+  nsresult rv = aFaviconURI->GetSpec(iconData->spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // URIs can arguably lack a host.
+  Unused << aFaviconURI->GetHost(iconData->host);
+  if (StringBeginsWith(iconData->host, "www."_ns)) {
+    iconData->host.Cut(0, 4);
+  }
+
+  // Note we can't set rootIcon here, because don't know the page it will be
+  // associated with. We'll do that later in SetAndFetchFaviconForPage if the
+  // icon doesn't exist; otherwise, if AsyncReplaceFaviconData updates an
+  // existing icon, it will take care of not overwriting an existing
+  // root = 1 value.
+
+  IconPayload payload;
+  payload.mimeType = aMimeType;
+  payload.data.Assign(TO_CHARBUFFER(aData.Elements()), aData.Length());
+  if (payload.mimeType.EqualsLiteral(SVG_MIME_TYPE)) {
+    payload.width = UINT16_MAX;
+  }
+  // There may already be a previous payload, so ensure to only have one.
+  iconData->payloads.Clear();
+  iconData->payloads.AppendElement(payload);
+
+  rv = OptimizeIconSizes(*iconData);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If there's not valid payload, don't store the icon into to the database.
+  if ((*iconData).payloads.Length() == 0) {
+    // We cannot optimize this favicon size and we are over the maximum size
+    // allowed, so we will not save data to the db to avoid bloating it.
+    mUnassociatedIcons.RemoveEntry(aFaviconURI);
+    return NS_ERROR_FAILURE;
+  }
+
+  // If the database contains an icon at the given url, we will update the
+  // database immediately so that the associated pages are kept in sync.
+  // Otherwise, do nothing and let the icon be picked up from the memory hash.
+  RefPtr<AsyncReplaceFaviconData> event =
+      new AsyncReplaceFaviconData(*iconData);
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  DB->DispatchToAsyncThread(event);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::ReplaceFaviconDataFromDataURL(
+    nsIURI* aFaviconURI, const nsAString& aDataURL, PRTime aExpiration,
+    nsIPrincipal* aLoadingPrincipal) {
+  NS_ENSURE_ARG(aFaviconURI);
+  NS_ENSURE_TRUE(aDataURL.Length() > 0, NS_ERROR_INVALID_ARG);
+  PRTime now = PR_Now();
+  if (aExpiration < now + MIN_FAVICON_EXPIRATION) {
+    // Invalid input, just use the default.
+    aExpiration = now + MAX_FAVICON_EXPIRATION;
+  }
+
+  nsCOMPtr<nsIURI> dataURI;
+  nsresult rv = NS_NewURI(getter_AddRefs(dataURI), aDataURL);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Use the data: protocol handler to convert the data.
+  nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIProtocolHandler> protocolHandler;
+  rv = ioService->GetProtocolHandler("data", getter_AddRefs(protocolHandler));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIPrincipal> loadingPrincipal = aLoadingPrincipal;
+  MOZ_ASSERT(loadingPrincipal,
+             "please provide aLoadingPrincipal for this favicon");
+  if (!loadingPrincipal) {
+    // Let's default to the nullPrincipal if no loadingPrincipal is provided.
+    AutoTArray<nsString, 2> params = {
+        u"nsFaviconService::ReplaceFaviconDataFromDataURL()"_ns,
+        u"nsFaviconService::ReplaceFaviconDataFromDataURL(...,"
+        " [optional aLoadingPrincipal])"_ns};
+    nsContentUtils::ReportToConsole(
+        nsIScriptError::warningFlag, "Security by Default"_ns,
+        nullptr,  // aDocument
+        nsContentUtils::eNECKO_PROPERTIES, "APIDeprecationWarning", params);
+
+    loadingPrincipal = NullPrincipal::CreateWithoutOriginAttributes();
+  }
+  NS_ENSURE_TRUE(loadingPrincipal, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsILoadInfo> loadInfo = new mozilla::net::LoadInfo(
+      loadingPrincipal,
+      nullptr,  // aTriggeringPrincipal
+      nullptr,  // aLoadingNode
+      nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_INHERITS_SEC_CONTEXT |
+          nsILoadInfo::SEC_ALLOW_CHROME | nsILoadInfo::SEC_DISALLOW_SCRIPT,
+      nsIContentPolicy::TYPE_INTERNAL_IMAGE_FAVICON);
+
+  nsCOMPtr<nsIChannel> channel;
+  rv = protocolHandler->NewChannel(dataURI, loadInfo, getter_AddRefs(channel));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Blocking stream is OK for data URIs.
+  nsCOMPtr<nsIInputStream> stream;
+  rv = channel->Open(getter_AddRefs(stream));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint64_t available64;
+  rv = stream->Available(&available64);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (available64 == 0 || available64 > UINT32_MAX / sizeof(uint8_t)) {
+    return NS_ERROR_FILE_TOO_BIG;
+  }
+  uint32_t available = (uint32_t)available64;
+
+  // Read all the decoded data.
+  nsTArray<uint8_t> buffer;
+  buffer.SetLength(available);
+  uint32_t numRead;
+  rv = stream->Read(TO_CHARBUFFER(buffer.Elements()), available, &numRead);
+  if (NS_FAILED(rv) || numRead != available) {
+    return rv;
+  }
+
+  nsAutoCString mimeType;
+  rv = channel->GetContentType(mimeType);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // ReplaceFaviconData can now do the dirty work.
+  rv = ReplaceFaviconData(aFaviconURI, buffer, mimeType, aExpiration);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::GetFaviconURLForPage(nsIURI* aPageURI,
+                                       nsIFaviconDataCallback* aCallback,
+                                       uint16_t aPreferredWidth) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aPageURI);
+  NS_ENSURE_ARG(aCallback);
+  // Use the default value, may be UINT16_MAX if a default is not set.
+  if (aPreferredWidth == 0) {
+    aPreferredWidth = mDefaultIconURIPreferredSize;
+  }
+
+  nsAutoCString pageSpec;
+  nsresult rv = aPageURI->GetSpec(pageSpec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString pageHost;
+  // It's expected that some domains may not have a host.
+  Unused << aPageURI->GetHost(pageHost);
+
+  RefPtr<AsyncGetFaviconURLForPage> event = new AsyncGetFaviconURLForPage(
+      pageSpec, pageHost, aPreferredWidth, aCallback);
+
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  DB->DispatchToAsyncThread(event);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::GetFaviconDataForPage(nsIURI* aPageURI,
+                                        nsIFaviconDataCallback* aCallback,
+                                        uint16_t aPreferredWidth) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aPageURI);
+  NS_ENSURE_ARG(aCallback);
+  // Use the default value, may be UINT16_MAX if a default is not set.
+  if (aPreferredWidth == 0) {
+    aPreferredWidth = mDefaultIconURIPreferredSize;
+  }
+
+  nsAutoCString pageSpec;
+  nsresult rv = aPageURI->GetSpec(pageSpec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString pageHost;
+  // It's expected that some domains may not have a host.
+  Unused << aPageURI->GetHost(pageHost);
+
+  RefPtr<AsyncGetFaviconDataForPage> event = new AsyncGetFaviconDataForPage(
+      pageSpec, pageHost, aPreferredWidth, aCallback);
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  DB->DispatchToAsyncThread(event);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::CopyFavicons(nsIURI* aFromPageURI, nsIURI* aToPageURI,
+                               uint32_t aFaviconLoadType,
+                               nsIFaviconDataCallback* aCallback) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG(aFromPageURI);
+  NS_ENSURE_ARG(aToPageURI);
+  NS_ENSURE_TRUE(
+      aFaviconLoadType >= nsIFaviconService::FAVICON_LOAD_PRIVATE &&
+          aFaviconLoadType <= nsIFaviconService::FAVICON_LOAD_NON_PRIVATE,
+      NS_ERROR_INVALID_ARG);
+
+  PageData fromPage;
+  nsresult rv = aFromPageURI->GetSpec(fromPage.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  PageData toPage;
+  rv = aToPageURI->GetSpec(toPage.spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool canAddToHistory;
+  nsNavHistory* navHistory = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(navHistory, NS_ERROR_OUT_OF_MEMORY);
+  rv = navHistory->CanAddURI(aToPageURI, &canAddToHistory);
+  NS_ENSURE_SUCCESS(rv, rv);
+  toPage.canAddToHistory =
+      !!canAddToHistory &&
+      aFaviconLoadType != nsIFaviconService::FAVICON_LOAD_PRIVATE;
+
+  RefPtr<AsyncCopyFavicons> event =
+      new AsyncCopyFavicons(fromPage, toPage, aCallback);
+
+  // Get the target thread and start the work.
+  // DB will be updated and observers notified when done.
+  RefPtr<Database> DB = Database::GetDatabase();
+  NS_ENSURE_STATE(DB);
+  DB->DispatchToAsyncThread(event);
+
+  return NS_OK;
+}
+
+nsresult nsFaviconService::GetFaviconLinkForIcon(nsIURI* aFaviconURI,
+                                                 nsIURI** _retval) {
+  NS_ENSURE_ARG(aFaviconURI);
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  nsAutoCString spec;
+  if (aFaviconURI) {
+    // List of protocols for which it doesn't make sense to generate a favicon
+    // uri since they can be directly loaded from disk or memory.
+    static constexpr nsLiteralCString sDirectRequestProtocols[] = {
+        // clang-format off
+        "about"_ns,
+        "cached-favicon"_ns,
+        "chrome"_ns,
+        "data"_ns,
+        "file"_ns,
+        "moz-page-thumb"_ns,
+        "page-icon"_ns,
+        "resource"_ns,
+        // clang-format on
+    };
+    nsAutoCString iconURIScheme;
+    if (NS_SUCCEEDED(aFaviconURI->GetScheme(iconURIScheme)) &&
+        std::find(std::begin(sDirectRequestProtocols),
+                  std::end(sDirectRequestProtocols),
+                  iconURIScheme) != std::end(sDirectRequestProtocols)) {
+      // Just return the input URL.
+      *_retval = do_AddRef(aFaviconURI).take();
+      return NS_OK;
+    }
+    nsresult rv = aFaviconURI->GetSpec(spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return GetFaviconLinkForIconString(spec, _retval);
+}
+
+// nsFaviconService::GetFaviconLinkForIconString
+//
+//    This computes a favicon URL with string input and using the cached
+//    default one to minimize parsing.
+
+nsresult nsFaviconService::GetFaviconLinkForIconString(const nsCString& aSpec,
+                                                       nsIURI** aOutput) {
+  if (aSpec.IsEmpty()) {
+    return GetDefaultFavicon(aOutput);
+  }
+
+  if (StringBeginsWith(aSpec, "chrome:"_ns)) {
+    // pass through for chrome URLs, since they can be referenced without
+    // this service
+    return NS_NewURI(aOutput, aSpec);
+  }
+
+  nsAutoCString annoUri;
+  annoUri.AssignLiteral("cached-favicon:");
+  annoUri += aSpec;
+  return NS_NewURI(aOutput, annoUri);
+}
+
+/**
+ * Checks the icon and evaluates if it needs to be optimized.
+ *
+ * @param aIcon
+ *        The icon to be evaluated.
+ */
+nsresult nsFaviconService::OptimizeIconSizes(IconData& aIcon) {
+  // TODO (bug 1346139): move optimization to the async thread.
+  MOZ_ASSERT(NS_IsMainThread());
+  // There should only be a single payload at this point, it may have to be
+  // split though, if it's an ico file.
+  MOZ_ASSERT(aIcon.payloads.Length() == 1);
+
+  // Even if the page provides a large image for the favicon (eg, a highres
+  // image or a multiresolution .ico file), don't try to store more data than
+  // needed.
+  IconPayload payload = aIcon.payloads[0];
+  if (payload.mimeType.EqualsLiteral(SVG_MIME_TYPE)) {
+    // Nothing to optimize, but check the payload size.
+    if (payload.data.Length() >= nsIFaviconService::MAX_FAVICON_BUFFER_SIZE) {
+      aIcon.payloads.Clear();
+    }
+    return NS_OK;
+  }
+
+  // Make space for the optimized payloads.
+  aIcon.payloads.Clear();
+
+  // decode image
+  nsCOMPtr<imgIContainer> container;
+  nsresult rv = GetImgTools()->DecodeImageFromBuffer(
+      payload.data.get(), payload.data.Length(), payload.mimeType,
+      getter_AddRefs(container));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // For ICO files, we must evaluate each of the frames we care about.
+  nsTArray<FrameData> framesInfo;
+  rv = GetFramesInfoForContainer(container, framesInfo);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  for (const auto& frameInfo : framesInfo) {
+    IconPayload newPayload;
+    newPayload.mimeType = nsLiteralCString(PNG_MIME_TYPE);
+    newPayload.width = frameInfo.width;
+    for (uint16_t size : gFaviconSizes) {
+      // The icon could be smaller than 16, that is our minimum.
+      // Icons smaller than 16px are kept as-is.
+      if (frameInfo.width >= 16) {
+        if (size > frameInfo.width) {
+          continue;
+        }
+        newPayload.width = size;
+      }
+
+      // If the original payload is png, the size is the same and not animated,
+      // rescale the image only if it's larger than the maximum allowed.
+      bool animated;
+      if (newPayload.mimeType.Equals(payload.mimeType) &&
+          newPayload.width == frameInfo.width &&
+          payload.data.Length() < nsIFaviconService::MAX_FAVICON_BUFFER_SIZE &&
+          (NS_FAILED(container->GetAnimated(&animated)) || !animated)) {
+        newPayload.data = payload.data;
+        break;
+      }
+
+      // Otherwise, scale and recompress. Rescaling will also take care of
+      // extracting a static image from an animated one.
+      // Since EncodeScaledImage uses SYNC_DECODE, it will pick the best
+      // frame.
+      nsCOMPtr<nsIInputStream> iconStream;
+      rv = GetImgTools()->EncodeScaledImage(container, newPayload.mimeType,
+                                            newPayload.width, newPayload.width,
+                                            u""_ns, getter_AddRefs(iconStream));
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Read the stream into the new buffer.
+      rv = NS_ConsumeStream(iconStream, UINT32_MAX, newPayload.data);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // If the icon size is good, we are done, otherwise try the next size.
+      if (newPayload.data.Length() <
+          nsIFaviconService::MAX_FAVICON_BUFFER_SIZE) {
+        break;
+      }
+    }
+
+    MOZ_ASSERT(newPayload.data.Length() <
+               nsIFaviconService::MAX_FAVICON_BUFFER_SIZE);
+    if (newPayload.data.Length() < nsIFaviconService::MAX_FAVICON_BUFFER_SIZE) {
+      aIcon.payloads.AppendElement(newPayload);
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsFaviconService::GetFaviconDataAsync(
+    const nsCString& aFaviconSpec, mozIStorageStatementCallback* aCallback) {
+  MOZ_ASSERT(aCallback, "Doesn't make sense to call this without a callback");
+
+  nsCOMPtr<mozIStorageAsyncStatement> stmt = mDB->GetAsyncStatement(
+      "/*Do not warn (bug no: not worth adding an index */ "
+      "SELECT data, width FROM moz_icons "
+      "WHERE fixed_icon_url_hash = hash(fixup_url(:url)) AND icon_url = :url "
+      "ORDER BY width DESC");
+  NS_ENSURE_STATE(stmt);
+
+  nsresult rv = URIBinder::Bind(stmt, "url"_ns, aFaviconSpec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<mozIStoragePendingStatement> pendingStatement;
+  return stmt->ExecuteAsync(aCallback, getter_AddRefs(pendingStatement));
+}
+
+NS_IMETHODIMP
+nsFaviconService::SetDefaultIconURIPreferredSize(uint16_t aDefaultSize) {
+  mDefaultIconURIPreferredSize = aDefaultSize > 0 ? aDefaultSize : UINT16_MAX;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFaviconService::PreferredSizeFromURI(nsIURI* aURI, uint16_t* _size) {
+  NS_ENSURE_ARG(aURI);
+  *_size = mDefaultIconURIPreferredSize;
+  nsAutoCString ref;
+  // Check for a ref first.
+  if (NS_FAILED(aURI->GetRef(ref)) || ref.Length() == 0) return NS_OK;
+
+  // Look for a "size=" fragment.
+  int32_t start = ref.RFind("size=");
+  if (start >= 0 && ref.Length() > static_cast<uint32_t>(start) + 5) {
+    nsDependentCSubstring size;
+    // This is safe regardless, since Rebind checks start is not over
+    // Length().
+    size.Rebind(ref, start + 5);
+    // Check if the string contains any non-digit.
+    auto begin = size.BeginReading(), end = size.EndReading();
+    for (const auto* ch = begin; ch < end; ++ch) {
+      if (*ch < '0' || *ch > '9') {
+        // Not a digit.
+        return NS_OK;
+      }
+    }
+    // Convert the string to an integer value.
+    nsresult rv;
+    uint16_t val = PromiseFlatCString(size).ToInteger(&rv);
+    if (NS_SUCCEEDED(rv)) {
+      *_size = val;
+    }
+  }
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// ExpireFaviconsStatementCallbackNotifier
+
+ExpireFaviconsStatementCallbackNotifier::
+    ExpireFaviconsStatementCallbackNotifier() = default;
+
+NS_IMETHODIMP
+ExpireFaviconsStatementCallbackNotifier::HandleCompletion(uint16_t aReason) {
+  // We should dispatch only if expiration has been successful.
+  if (aReason != mozIStorageStatementCallback::REASON_FINISHED) return NS_OK;
+
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (observerService) {
+    (void)observerService->NotifyObservers(
+        nullptr, NS_PLACES_FAVICONS_EXPIRED_TOPIC_ID, nullptr);
+  }
+
+  return NS_OK;
+}
diff --git a/toolkit/components/places/nsFaviconService.h b/toolkit/components/places/nsFaviconService.h
new file mode 100644
index 0000000000..4485bbaf28
--- /dev/null
+++ b/toolkit/components/places/nsFaviconService.h
@@ -0,0 +1,145 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsFaviconService_h_
+#define nsFaviconService_h_
+
+#include <utility>
+
+#include "Database.h"
+#include "FaviconHelpers.h"
+#include "imgITools.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/storage.h"
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIFaviconService.h"
+#include "nsINamed.h"
+#include "nsITimer.h"
+#include "nsServiceManagerUtils.h"
+#include "nsString.h"
+#include "nsTHashtable.h"
+#include "nsToolkitCompsCID.h"
+#include "nsURIHashKey.h"
+#include "prtime.h"
+
+// The target dimension in pixels for favicons we store, in reverse order.
+// When adding/removing sizes from here, make sure to update the vector size.
+extern const uint16_t gFaviconSizes[7];
+
+// forward class definitions
+class mozIStorageStatementCallback;
+
+class UnassociatedIconHashKey : public nsURIHashKey {
+ public:
+  explicit UnassociatedIconHashKey(const nsIURI* aURI)
+      : nsURIHashKey(aURI), created(PR_Now()) {}
+  UnassociatedIconHashKey(UnassociatedIconHashKey&& aOther) noexcept
+      : nsURIHashKey(std::move(aOther)),
+        iconData(std::move(aOther.iconData)),
+        created(std::move(aOther.created)) {}
+  mozilla::places::IconData iconData;
+  PRTime created;
+};
+
+class nsFaviconService final : public nsIFaviconService,
+                               public nsITimerCallback,
+                               public nsINamed {
+ public:
+  nsFaviconService();
+
+  /**
+   * Obtains the service's object.
+   */
+  static already_AddRefed<nsFaviconService> GetSingleton();
+
+  /**
+   * Initializes the service's object.  This should only be called once.
+   */
+  nsresult Init();
+
+  /**
+   * Returns a cached pointer to the favicon service for consumers in the
+   * places directory.
+   */
+  static nsFaviconService* GetFaviconService() {
+    if (!gFaviconService) {
+      nsCOMPtr<nsIFaviconService> serv =
+          do_GetService(NS_FAVICONSERVICE_CONTRACTID);
+      NS_ENSURE_TRUE(serv, nullptr);
+      NS_ASSERTION(gFaviconService, "Should have static instance pointer now");
+    }
+    return gFaviconService;
+  }
+
+  // addition to API for strings to prevent excessive parsing of URIs
+  nsresult GetFaviconLinkForIconString(const nsCString& aSpec,
+                                       nsIURI** aOutput);
+
+  nsresult OptimizeIconSizes(mozilla::places::IconData& aIcon);
+
+  /**
+   * Obtains the favicon data asynchronously.
+   *
+   * @param aFaviconSpec
+   *        The spec of the URI representing the favicon we are looking for.
+   * @param aCallback
+   *        The callback where results or errors will be dispatch to.  In the
+   *        returned result, the favicon binary data will be at index 0, and the
+   *        mime type will be at index 1.
+   */
+  nsresult GetFaviconDataAsync(const nsCString& aFaviconSpec,
+                               mozIStorageStatementCallback* aCallback);
+
+  /**
+   * Clears the image cache for the given image spec.
+   *
+   * @param aImageURI
+   *        The URI of the image to clear cache for.
+   */
+  void ClearImageCache(nsIURI* aImageURI);
+
+  static mozilla::Atomic<int64_t> sLastInsertedIconId;
+  static void StoreLastInsertedId(const nsACString& aTable,
+                                  const int64_t aLastInsertedId);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIFAVICONSERVICE
+  NS_DECL_NSITIMERCALLBACK
+  NS_DECL_NSINAMED
+
+ private:
+  imgITools* GetImgTools() {
+    if (!mImgTools) {
+      mImgTools = do_CreateInstance("@mozilla.org/image/tools;1");
+    }
+    return mImgTools;
+  }
+
+  ~nsFaviconService();
+
+  RefPtr<mozilla::places::Database> mDB;
+
+  nsCOMPtr<nsITimer> mExpireUnassociatedIconsTimer;
+  nsCOMPtr<imgITools> mImgTools;
+
+  static nsFaviconService* gFaviconService;
+
+  /**
+   * A cached URI for the default icon. We return this a lot, and don't want to
+   * re-parse and normalize our unchanging string many times.  Important: do
+   * not return this directly; use Clone() since callers may change the object
+   * they get back. May be null, in which case it needs initialization.
+   */
+  nsCOMPtr<nsIURI> mDefaultIcon;
+
+  // This class needs access to the icons cache.
+  friend class mozilla::places::AsyncReplaceFaviconData;
+  nsTHashtable<UnassociatedIconHashKey> mUnassociatedIcons;
+
+  uint16_t mDefaultIconURIPreferredSize;
+};
+
+#endif  // nsFaviconService_h_
diff --git a/toolkit/components/places/nsIFaviconService.idl b/toolkit/components/places/nsIFaviconService.idl
new file mode 100644
index 0000000000..5bc26545c6
--- /dev/null
+++ b/toolkit/components/places/nsIFaviconService.idl
@@ -0,0 +1,339 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+interface nsIPrincipal;
+interface mozIPlacesPendingOperation;
+interface nsIFaviconDataCallback;
+
+[scriptable, uuid(e81e0b0c-b9f1-4c2e-8f3c-b809933cf73c)]
+interface nsIFaviconService : nsISupports
+{
+  // The favicon is being loaded from a private browsing window
+  const unsigned long FAVICON_LOAD_PRIVATE = 1;
+  // The favicon is being loaded from a non-private browsing window
+  const unsigned long FAVICON_LOAD_NON_PRIVATE = 2;
+
+  /**
+   * The limit in bytes of the size of favicons in memory and passed via the
+   * favicon protocol.
+   */
+  const unsigned long MAX_FAVICON_BUFFER_SIZE = 65536;
+
+  /**
+   * For a given icon URI, this will return a URI that will result in the image.
+   * In most cases, this is an annotation URI.  For chrome URIs, this will do
+   * nothing but returning the input URI.
+   *
+   * No validity checking is done. If you pass an icon URI that we've never
+   * seen, you'll get back a URI that references an invalid icon. The
+   * cached-favicon protocol handler's special case for cached favicon will
+   * resolve invalid icons to the default icon, although without caching.
+   * For invalid chrome URIs, you'll get a broken image.
+   *
+   * @param aFaviconURI
+   *        The URI of an icon in the favicon service.
+   * @return A URI that will give you the icon image.  This is NOT the URI of
+   *         the icon as set on the page, but a URI that will give you the
+   *         data out of the favicon service.  For a normal page with a
+   *         favicon we've stored, this will be an annotation URI which will
+   *         then cause the corresponding favicon data to be loaded async from
+   *         this service.  For pages where we don't have a favicon, this will
+   *         be a chrome URI of the default icon. For chrome URIs, the
+   *         output will be the same as the input.
+   */
+  nsIURI getFaviconLinkForIcon(in nsIURI aFaviconURI);
+
+  /**
+   * Expire all known favicons from the database.
+   *
+   * @note This is an async method.
+   *       On successful completion a "places-favicons-expired" notification is
+   *       dispatched through observer's service.
+   */
+  void expireAllFavicons();
+
+  /**
+   * Sets the default size returned by preferredSizeFromURI when the uri doesn't
+   * specify a size ref. If this is not invoked first, or 0 is passed to it,
+   * preferredSizeFromURI() will return UINT16_MAX, that matches the biggest
+   * icon available.
+   */
+  void setDefaultIconURIPreferredSize(in unsigned short aDefaultSize);
+
+  /**
+   * Tries to extract the preferred size from an icon uri ref fragment.
+   *
+   * @param aURI
+   *        The URI to parse.
+   * @return The preferred size, or a default size set through
+   *         setDefaultIconURIPreferredSize, or UINT16_MAX if neither are set.
+   */
+  unsigned short preferredSizeFromURI(in nsIURI aURI);
+
+  /**
+   * The default favicon URI
+   */
+  readonly attribute nsIURI defaultFavicon;
+
+  /**
+   * The default favicon mimeType
+   */
+  readonly attribute AUTF8String defaultFaviconMimeType;
+
+  /**
+   * Declares that a given page uses a favicon with the given URI and
+   * attempts to fetch and save the icon data by loading the favicon URI
+   * through an async network request.
+   *
+   * If the icon data already exists, we won't try to reload the icon unless
+   * aForceReload is true.  Similarly, if the icon is in the failed favicon
+   * cache we won't do anything unless aForceReload is true, in which case
+   * we'll try to reload the favicon.
+   *
+   * This function will only save favicons for pages that are already stored in
+   * the database, like visited pages or bookmarks.  For any other URIs, it
+   * will succeed but do nothing.  This function will also ignore the error
+   * page favicon URI (see FAVICON_ERRORPAGE_URL below).
+   *
+   * Icons that fail to load will automatically be added to the failed favicon
+   * cache, and this function will not save favicons for non-bookmarked URIs
+   * when history is disabled.
+   *
+   * @note This function is identical to
+   *       nsIFaviconService::setAndLoadFaviconForPage.
+   *
+   * @param aPageURI
+   *        URI of the page whose favicon is being set.
+   * @param aFaviconURI
+   *        URI of the favicon to associate with the page.
+   * @param aForceReload
+   *        If aForceReload is false, we try to reload the favicon only if we
+   *        don't have it or it has expired from the cache.  Setting
+   *        aForceReload to true causes us to reload the favicon even if we
+   *        have a usable copy.
+   * @param aFaviconLoadType
+   *        Set to FAVICON_LOAD_PRIVATE if the favicon is loaded from a private
+   *        browsing window.  Set to FAVICON_LOAD_NON_PRIVATE otherwise.
+   * @param [optional] aCallback
+   *        Once we're done setting and/or fetching the favicon, we invoke this
+   *        callback.
+   * @param [optional] aLoadingPrincipal
+   *        Principal of the page whose favicon is being set. If this argument
+   *        is omitted, the loadingPrincipal defaults to the nullPrincipal.
+   * @param [optional] aRequestContextID
+   *        used to inform Necko of how to link the
+   *        favicon request with other requests in the same tab.
+   *
+   * @see nsIFaviconDataCallback in nsIFaviconService.idl.
+   */
+  mozIPlacesPendingOperation setAndFetchFaviconForPage(
+    in nsIURI aPageURI,
+    in nsIURI aFaviconURI,
+    in boolean aForceReload,
+    in unsigned long aFaviconLoadType,
+    [optional] in nsIFaviconDataCallback aCallback,
+    [optional] in nsIPrincipal aLoadingPrincipal,
+    [optional] in unsigned long long aRequestContextID);
+
+  /**
+   * Sets the data for a given favicon URI either by replacing existing data in
+   * the database or taking the place of otherwise fetched icon data when
+   * calling setAndFetchFaviconForPage later.
+   *
+   * Favicon data for favicon URIs that are not associated with a page URI via
+   * setAndFetchFaviconForPage will be stored in memory, but may be expired at
+   * any time, so you should make an effort to associate favicon URIs with page
+   * URIs as soon as possible.
+   *
+   * It's better to not use this function for chrome: icon URIs since you can
+   * reference the chrome image yourself. getFaviconLinkForIcon/Page will ignore
+   * any associated data if the favicon URI is "chrome:" and just return the
+   * same chrome URI.
+   *
+   * This function does NOT send out notifications that the data has changed.
+   * Pages using this favicons that are visible in history or bookmarks views
+   * will keep the old icon until they have been refreshed by other means.
+   *
+   * This function tries to optimize the favicon size, if it is bigger
+   * than a defined limit we will try to convert it to a 16x16 png image.
+   * If the conversion fails and favicon is still bigger than our max accepted
+   * size it won't be saved.
+   *
+   * @param aFaviconURI
+   *        URI of the favicon whose data is being set.
+   * @param aData
+   *        Binary contents of the favicon to save
+   * @param aMimeType
+   *        MIME type of the data to store.  This is important so that we know
+   *        what to report when the favicon is used.  You should always set this
+   *        param unless you are clearing an icon.
+   * @param [optional] aExpiration
+   *        Time in microseconds since the epoch when this favicon expires.
+   *        Until this time, we won't try to load it again.
+   * @throws NS_ERROR_FAILURE
+   *         Thrown if the favicon is overbloated and won't be saved to the db.
+   */
+  void replaceFaviconData(in nsIURI aFaviconURI,
+                          in Array<octet> aData,
+                          in AUTF8String aMimeType,
+                          [optional] in PRTime aExpiration);
+
+  /**
+   * Same as replaceFaviconData but the data is provided by a string
+   * containing a data URL.
+   *
+   * @see replaceFaviconData
+   *
+   * @param aFaviconURI
+   *        URI of the favicon whose data is being set.
+   * @param aDataURL
+   *        string containing a data URL that represents the contents of
+   *        the favicon to save
+   * @param [optional] aExpiration
+   *        Time in microseconds since the epoch when this favicon expires.
+   *        Until this time, we won't try to load it again.
+   * @param [optional] aLoadingPrincipal
+   *        Principal of the page whose favicon is being set. If this argument
+   *        is omitted, the loadingPrincipal defaults to the nullPrincipal.
+   * @throws NS_ERROR_FAILURE
+   *         Thrown if the favicon is overbloated and won't be saved to the db.
+   */
+  void replaceFaviconDataFromDataURL(in nsIURI aFaviconURI,
+                                     in AString aDataURL,
+                                     [optional] in PRTime aExpiration,
+                                     [optional] in nsIPrincipal aLoadingPrincipal);
+
+  /**
+   * Retrieves the favicon URI associated to the given page, if any.
+   *
+   * @param aPageURI
+   *        URI of the page whose favicon URI we're looking up.
+   * @param aCallback
+   *        This callback is always invoked to notify the result of the lookup.
+   *        The aURI parameter will be the favicon URI, or null when no favicon
+   *        is associated with the page or an error occurred while fetching it.
+   *        aDataLen will be always 0, aData will be an empty array, and
+   *        aMimeType will be an empty string, regardless of whether a favicon
+   *        was found.
+   * @param [optional] aPreferredWidth
+   *        The preferred icon width, skip or pass 0 for the default value,
+   *        set through setDefaultIconURIPreferredSize.
+   *
+   * @note If a favicon specific to this page cannot be found, this will try to
+   *       fallback to the /favicon.ico for the root domain.
+   *
+   * @see nsIFaviconDataCallback in nsIFaviconService.idl.
+   */
+  void getFaviconURLForPage(in nsIURI aPageURI,
+                            in nsIFaviconDataCallback aCallback,
+                            [optional] in unsigned short aPreferredWidth);
+
+  /**
+   * Retrieves the favicon URI and data associated to the given page, if any.
+   * If the page icon is not available, it will try to return the root domain
+   * icon data, when it's known.
+   *
+   * @param aPageURI
+   *        URI of the page whose favicon URI and data we're looking up.
+   * @param aCallback
+   *        This callback is always invoked to notify the result of the lookup.  The aURI
+   *        parameter will be the favicon URI, or null when no favicon is
+   *        associated with the page or an error occurred while fetching it.  If
+   *        aURI is not null, the other parameters may contain the favicon data.
+   *        However, if no favicon data is currently associated with the favicon
+   *        URI, aDataLen will be 0, aData will be an empty array, and aMimeType
+   *        will be an empty string.
+   * @param [optional] aPreferredWidth
+   *        The preferred icon width, skip or pass 0 for the default value,
+   *        set through setDefaultIconURIPreferredSize.
+   * @note If a favicon specific to this page cannot be found, this will try to
+   *       fallback to the /favicon.ico for the root domain.
+   *
+   * @see nsIFaviconDataCallback in nsIFaviconService.idl.
+   */
+  void getFaviconDataForPage(in nsIURI aPageURI,
+                             in nsIFaviconDataCallback aCallback,
+                             [optional] in unsigned short aPreferredWidth);
+
+  /**
+   * Copies cached favicons from a page to another one.
+   *
+   * @param aFromPageURI
+   *        URI of the originating page.
+   * @param aToPageURI
+   *        URI of the destination page.
+   * @param aFaviconLoadType
+   *        Set to FAVICON_LOAD_PRIVATE if the copy is started from a private
+   *        browsing window.  Set to FAVICON_LOAD_NON_PRIVATE otherwise.
+   * @param [optional] aCallback
+   *        Once we're done copying the favicon, we invoke this callback.
+   *        If a copy has been done, the callback will report one of the
+   *        favicons uri as aFaviconURI, otherwise all the params will be null.
+   */
+  void copyFavicons(in nsIURI aFromPageURI,
+                    in nsIURI aToPageURI,
+                    in unsigned long aFaviconLoadType,
+                    [optional] in nsIFaviconDataCallback aCallback);
+};
+
+[scriptable, function, uuid(c85e5c82-b70f-4621-9528-beb2aa47fb44)]
+interface nsIFaviconDataCallback : nsISupports
+{
+  /**
+   * Called when the required favicon's information is available.
+   *
+   * It's up to the invoking method to state if the callback is always invoked,
+   * or called on success only.  Check the method documentation to ensure that.
+   *
+   * The caller will receive the most information we can gather on the icon,
+   * but it's not guaranteed that all of them will be set.  For some method
+   * we could not know the favicon's data (it could just be too expensive to
+   * get it, or the method does not require we actually have any data).
+   * It's up to the caller to check aDataLen > 0 before using any data-related
+   * information like mime-type or data itself.
+   *
+   * @param aFaviconURI
+   *        Receives the "favicon URI" (not the "favicon link URI") associated
+   *        to the requested page.  This can be null if there is no associated
+   *        favicon URI, or the callback is notifying a failure.
+   * @param aDataLen
+   *        Size of the icon data in bytes.  Notice that a value of 0 does not
+   *        necessarily mean that we don't have an icon.
+   * @param aData
+   *        Icon data, or an empty array if aDataLen is 0.
+   * @param aMimeType
+   *        Mime type of the icon, or an empty string if aDataLen is 0.
+   * @param aWidth
+   *        Width of the icon. 0 if the width is unknown or if the icon is
+   *        vectorial.
+   *
+   * @note If you want to open a network channel to access the favicon, it's
+   *       recommended that you call the getFaviconLinkForIcon method to convert
+   *       the "favicon URI" into a "favicon link URI".
+   */
+  void onComplete(in nsIURI aFaviconURI,
+                  in unsigned long aDataLen,
+                  [const,array,size_is(aDataLen)] in octet aData,
+                  in AUTF8String aMimeType,
+                  in unsigned short aWidth);
+};
+
+%{C++
+
+/**
+ * Notification sent when all favicons are expired.
+ */
+#define NS_PLACES_FAVICONS_EXPIRED_TOPIC_ID "places-favicons-expired"
+
+#define FAVICON_DEFAULT_URL "chrome://global/skin/icons/defaultFavicon.svg"
+#define FAVICON_DEFAULT_MIMETYPE "image/svg+xml"
+
+#define FAVICON_ERRORPAGE_URL "chrome://global/skin/icons/info.svg"
+#define FAVICON_CERTERRORPAGE_URL "chrome://global/skin/icons/warning.svg"
+
+%}
diff --git a/toolkit/components/places/nsINavBookmarksService.idl b/toolkit/components/places/nsINavBookmarksService.idl
new file mode 100644
index 0000000000..1891d7c6d0
--- /dev/null
+++ b/toolkit/components/places/nsINavBookmarksService.idl
@@ -0,0 +1,211 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIFile;
+interface nsIURI;
+interface nsITransaction;
+
+/**
+ * The BookmarksService interface provides methods for managing bookmarked
+ * history items.  Bookmarks consist of a set of user-customizable
+ * folders.  A URI in history can be contained in one or more such folders.
+ */
+
+[scriptable, uuid(24533891-afa6-4663-b72d-3143d03f1b04)]
+interface nsINavBookmarksService : nsISupports
+{
+  /**
+   * The item ID of the top-level folder that contain the tag "folders".
+   */
+  readonly attribute long long tagsFolder;
+
+  /**
+   * The total number of Sync changes (inserts, updates, deletes, merges, and
+   * uploads) recorded since Places startup for all bookmarks.
+   *
+   * Note that this is *not* the number of bookmark syncs. It's a monotonically
+   * increasing counter incremented for every change that affects a bookmark's
+   * `syncChangeCounter`.
+   *
+   * The counter can be used to avoid keeping an exclusive transaction open for
+   * time-consuming work. One way to do that is to store the current value of
+   * the counter, do the work, start a transaction, check the current value
+   * again, and compare it to the stored value to determine if the database
+   * changed during the work.
+   *
+   * The bookmarks mirror does this to check for changes between building and
+   * applying a merged tree. This avoids blocking the main Places connection
+   * during the merge, and ensures that the new tree still applies cleanly.
+   */
+  readonly attribute long long totalSyncChanges;
+
+  /**
+   * This value should be used for APIs that allow passing in an index
+   * where an index is not known, or not required to be specified.
+   * e.g.: When appending an item to a folder.
+   */
+  const short DEFAULT_INDEX = -1;
+
+  const unsigned short TYPE_BOOKMARK = 1;
+  const unsigned short TYPE_FOLDER = 2;
+  const unsigned short TYPE_SEPARATOR = 3;
+  // Dynamic containers are deprecated and unsupported.
+  // This const exists just to avoid reusing the value.
+  const unsigned short TYPE_DYNAMIC_CONTAINER = 4;
+
+  // Change source constants. These are used to distinguish changes made by
+  // Sync and bookmarks import from other Places consumers, though they can
+  // be extended to support other callers. Sources are passed as optional
+  // parameters to methods used by Sync, and forwarded to observers.
+  const unsigned short SOURCE_DEFAULT = 0;
+  const unsigned short SOURCE_SYNC = 1;
+  const unsigned short SOURCE_IMPORT = 2;
+  const unsigned short SOURCE_SYNC_REPARENT_REMOVED_FOLDER_CHILDREN = 4;
+  const unsigned short SOURCE_RESTORE = 5;
+  const unsigned short SOURCE_RESTORE_ON_STARTUP = 6;
+
+  /**
+   * Sync status flags, stored in Places for each item. These affect conflict
+   * resolution, when an item is changed both locally and remotely; deduping,
+   * when a local item matches a remote item with similar contents and different
+   * GUIDs; and whether we write a tombstone when an item is deleted locally.
+   *
+   * Status  | Description               | Conflict   | Can     | Needs
+   *         |                           | resolution | dedupe? | tombstone?
+   * -----------------------------------------------------------------------
+   * UNKNOWN | Automatically restored    | Prefer     | No      | No
+   *         | on startup to recover     | deletion   |         |
+   *         | from database corruption, |            |         |
+   *         | or sync ID change on      |            |         |
+   *         | server.                   |            |         |
+   * -----------------------------------------------------------------------
+   * NEW     | Item not uploaded to      | Prefer     | Yes     | No
+   *         | server yet, or Sync       | newer      |         |
+   *         | disconnected.             |            |         |
+   * -----------------------------------------------------------------------
+   * NORMAL  | Item uploaded to server.  | Prefer     | No      | Yes
+   *         |                           | newer      |         |
+   */
+  const unsigned short SYNC_STATUS_UNKNOWN = 0;
+  const unsigned short SYNC_STATUS_NEW = 1;
+  const unsigned short SYNC_STATUS_NORMAL = 2;
+
+  /**
+   * Inserts a child bookmark into the given folder.
+   *
+   *  @param aParentId
+   *         The id of the parent folder
+   *  @param aURI
+   *         The URI to insert
+   *  @param aIndex
+   *         The index to insert at, or DEFAULT_INDEX to append
+   *  @param aTitle
+   *         The title for the new bookmark
+   *  @param [optional] aGuid
+   *         The GUID to be set for the new item.  If not set, a new GUID is
+   *         generated.  Unless you've a very sound reason, such as an undo
+   *         manager implementation, do not pass this argument.
+   *  @param [optional] aSource
+   *         The change source. This is forwarded to all bookmark observers,
+   *         allowing them to distinguish between insertions from different
+   *         callers. Defaults to SOURCE_DEFAULT if omitted.
+   *  @return The ID of the newly-created bookmark.
+   *
+   *  @note aTitle will be truncated to TITLE_LENGTH_MAX and
+   *        aURI will be truncated to URI_LENGTH_MAX.
+   *  @throws if aGuid is malformed.
+   */
+  [can_run_script]
+  long long insertBookmark(in long long aParentId, in nsIURI aURI,
+                           in long aIndex, in AUTF8String aTitle,
+                           [optional] in ACString aGuid,
+                           [optional] in unsigned short aSource);
+
+  /**
+   * Removes a child item. Used to delete a bookmark or separator.
+   *  @param aItemId
+   *         The child item to remove
+   *  @param [optional] aSource
+   *         The change source, forwarded to all bookmark observers. Defaults
+   *         to SOURCE_DEFAULT.
+   */
+  [can_run_script]
+  void removeItem(in long long aItemId, [optional] in unsigned short aSource);
+
+  /**
+   * Creates a new child folder and inserts it under the given parent.
+   *  @param aParentFolder
+   *         The id of the parent folder
+   *  @param aName
+   *         The name of the new folder
+   *  @param aIndex
+   *         The index to insert at, or DEFAULT_INDEX to append
+   *  @param [optional] aGuid
+   *         The GUID to be set for the new item.  If not set, a new GUID is
+   *         generated.  Unless you've a very sound reason, such as an undo
+   *         manager implementation, do not pass this argument.
+   *  @param [optional] aSource
+   *         The change source, forwarded to all bookmark observers. Defaults
+   *         to SOURCE_DEFAULT.
+   *  @return The ID of the newly-inserted folder.
+   *  @throws if aGuid is malformed.
+   */
+  [can_run_script]
+  long long createFolder(in long long aParentFolder, in AUTF8String name,
+                         in long index,
+                         [optional] in ACString aGuid,
+                         [optional] in unsigned short aSource);
+
+  /**
+   * Set the title for an item.
+   *  @param aItemId
+   *         The id of the item whose title should be updated.
+   *  @param aTitle
+   *         The new title for the bookmark.
+   *  @param [optional] aSource
+   *         The change source, forwarded to all bookmark observers. Defaults
+   *         to SOURCE_DEFAULT.
+   *
+   *  @note  aTitle will be truncated to TITLE_LENGTH_MAX.
+   */
+  [can_run_script]
+  void setItemTitle(in long long aItemId, in AUTF8String aTitle,
+                    [optional] in unsigned short aSource);
+
+  /**
+   * Get the title for an item.
+   *
+   * If no item title is available it will return a void string (null in JS).
+   *
+   *  @param aItemId
+   *         The id of the item whose title should be retrieved
+   *  @return The title of the item.
+   */
+  AUTF8String getItemTitle(in long long aItemId);
+
+  /**
+   * Set the last modified time for an item.
+   *
+   * @param aItemId
+   *        the id of the item whose last modified time should be updated.
+   * @param aLastModified
+   *        the new last modified value in microseconds.  Note that it is
+   *        rounded down to milliseconds precision.
+   * @param [optional] aSource
+   *        The change source, forwarded to all bookmark observers. Defaults
+   *        to SOURCE_DEFAULT.
+   *
+   * @note This is the only method that will send an itemChanged notification
+   *       for the property.  lastModified will still be updated in
+   *       any other method that changes an item property, but we will send
+   *       the corresponding itemChanged notification instead.
+   */
+  [can_run_script]
+  void setItemLastModified(in long long aItemId,
+                           in PRTime aLastModified,
+                           [optional] in unsigned short aSource);
+};
diff --git a/toolkit/components/places/nsINavHistoryService.idl b/toolkit/components/places/nsINavHistoryService.idl
new file mode 100644
index 0000000000..5b118911a1
--- /dev/null
+++ b/toolkit/components/places/nsINavHistoryService.idl
@@ -0,0 +1,1160 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Using Places services after quit-application is not reliable, so make
+ * sure to do any shutdown work on quit-application, or history
+ * synchronization could fail, losing latest changes.
+ */
+
+#include "nsISupports.idl"
+
+interface nsIArray;
+interface nsIFile;
+interface nsIObserver;
+interface nsIVariant;
+interface nsIURI;
+
+interface mozIStorageConnection;
+interface mozIStorageStatementCallback;
+interface mozIStoragePendingStatement;
+interface nsIAsyncShutdownClient;
+
+interface nsINavHistoryContainerResultNode;
+interface nsINavHistoryQueryResultNode;
+interface nsINavHistoryQuery;
+interface nsINavHistoryQueryOptions;
+interface nsINavHistoryResult;
+
+[scriptable, uuid(91d104bb-17ef-404b-9f9a-d9ed8de6824c)]
+interface nsINavHistoryResultNode : nsISupports
+{
+  /**
+   * Indentifies the parent result node in the result set. This is null for
+   * top level nodes.
+   */
+  readonly attribute nsINavHistoryContainerResultNode parent;
+
+  /**
+   * The history-result to which this node belongs.
+   */
+  readonly attribute nsINavHistoryResult parentResult;
+
+  /**
+   * URI of the resource in question. For visits and URLs, this is the URL of
+   * the page. For folders and queries, this is the place: URI of the
+   * corresponding folder or query. This may be empty for other types of
+   * objects like host containers.
+   */
+  readonly attribute AUTF8String uri;
+
+  /**
+   * Identifies the type of this node. This node can then be QI-ed to the
+   * corresponding specialized result node interface.
+   */
+  const unsigned long RESULT_TYPE_URI = 0;               // nsINavHistoryResultNode
+
+  // Visit nodes are deprecated and unsupported.
+  // This line exists just to avoid reusing the value:
+  // const unsigned long RESULT_TYPE_VISIT = 1;
+
+  // Full visit nodes are deprecated and unsupported.
+  // This line exists just to avoid reusing the value:
+  // const unsigned long RESULT_TYPE_FULL_VISIT = 2;
+
+  // Dynamic containers are deprecated and unsupported.
+  // This const exists just to avoid reusing the value:
+  // const unsigned long RESULT_TYPE_DYNAMIC_CONTAINER = 4; // nsINavHistoryContainerResultNode
+
+  const unsigned long RESULT_TYPE_QUERY = 5;             // nsINavHistoryQueryResultNode
+  const unsigned long RESULT_TYPE_FOLDER = 6;            // nsINavHistoryQueryResultNode
+  const unsigned long RESULT_TYPE_SEPARATOR = 7;         // nsINavHistoryResultNode
+  const unsigned long RESULT_TYPE_FOLDER_SHORTCUT = 9;   // nsINavHistoryQueryResultNode
+  readonly attribute unsigned long type;
+
+  /**
+   * Title of the web page, or of the node's query (day, host, folder, etc)
+   */
+  readonly attribute AUTF8String title;
+
+  /**
+   * Total number of times the URI has ever been accessed. For hosts, this
+   * is the total of the children under it, NOT the total times the host has
+   * been accessed (this would require an additional query, so is not given
+   * by default when most of the time it is never needed).
+   */
+  readonly attribute unsigned long accessCount;
+
+  /**
+   * This is the time the user accessed the page.
+   *
+   * If this is a visit, it is the exact time that the page visit occurred.
+   *
+   * If this is a URI, it is the most recent time that the URI was visited.
+   * Even if you ask for all URIs for a given date range long ago, this might
+   * contain today's date if the URI was visited today.
+   *
+   * For hosts, or other node types with children, this is the most recent
+   * access time for any of the children.
+   *
+   * For days queries this is the respective endTime - a maximum possible
+   * visit time to fit in the day range.
+   */
+  readonly attribute PRTime time;
+
+  /**
+   * This URI can be used as an image source URI and will give you the favicon
+   * for the page. It is *not* the URI of the favicon, but rather something
+   * that will resolve to the actual image.
+   *
+   * In most cases, this is an annotation URI that will query the favicon
+   * service. If the entry has no favicon, this is the chrome URI of the
+   * default favicon. If the favicon originally lived in chrome, this will
+   * be the original chrome URI of the icon.
+   */
+  readonly attribute AUTF8String icon;
+
+  /**
+   * This is the number of levels between this node and the top of the
+   * hierarchy. The members of result.children have indentLevel = 0, their
+   * children have indentLevel = 1, etc. The indent level of the root node is
+   * set to -1.
+   */
+  readonly attribute long indentLevel;
+
+  /**
+   * When this item is in a bookmark folder (parent is of type folder), this is
+   * the index into that folder of this node. These indices start at 0 and
+   * increase in the order that they appear in the bookmark folder. For items
+   * that are not in a bookmark folder, this value is -1.
+   */
+  readonly attribute long bookmarkIndex;
+
+  /**
+   * If the node is an item (bookmark, folder or a separator) this value is the
+   * row ID of that bookmark in the database. For other nodes, this value is
+   * set to -1.
+   */
+  readonly attribute long long itemId;
+
+  /**
+   * If the node is an item (bookmark, folder or a separator) this value is the
+   * time that the item was created. For other nodes, this value is 0.
+   */
+  readonly attribute PRTime dateAdded;
+
+  /**
+   * If the node is an item (bookmark, folder or a separator) this value is the
+   * time that the item was last modified. For other nodes, this value is 0.
+   *
+   *  @note When an item is added lastModified is set to the same value as
+   *        dateAdded.
+   */
+  readonly attribute PRTime lastModified;
+
+  /**
+   * For uri nodes, this is a sorted list of the tags, delimited with commans,
+   * for the uri represented by this node. Otherwise this is an empty string.
+   */
+  readonly attribute AString tags;
+
+  /**
+   * The unique ID associated with the page. It my return an empty string
+   * if the result node is a non-URI node.
+   */
+  readonly attribute ACString pageGuid;
+
+  /**
+   * The unique ID associated with the bookmark. It returns an empty string
+   * if the result node is not associated with a bookmark, a folder or a
+   * separator.
+   */
+  readonly attribute ACString bookmarkGuid;
+
+  /**
+   * The unique ID associated with the history visit. For node types other than
+   * history visit nodes, this value is -1.
+   */
+  readonly attribute long long visitId;
+
+  /**
+   * The transition type associated with this visit. For node types other than
+   * history visit nodes, this value is 0.
+   */
+  readonly attribute unsigned long visitType;
+};
+
+
+/**
+ * Base class for container results. This includes all types of groupings.
+ * Bookmark folders and places queries will be QueryResultNodes which extends
+ * these items.
+ */
+[scriptable, uuid(3E9CC95F-0D93-45F1-894F-908EEB9866D7)]
+interface nsINavHistoryContainerResultNode : nsINavHistoryResultNode
+{
+
+  /**
+   * Set this to allow descent into the container. When closed, attempting
+   * to call getChildren or childCount will result in an error. You should
+   * set this to false when you are done reading.
+   *
+   * For HOST and DAY groupings, doing this is free since the children have
+   * been precomputed. For queries and bookmark folders, being open means they
+   * will keep themselves up-to-date by listening for updates and re-querying
+   * as needed.
+   */
+  attribute boolean containerOpen;
+
+  /**
+   * Indicates whether the container is closed, loading, or opened.  Loading
+   * implies that the container has been opened asynchronously and has not yet
+   * fully opened.
+   */
+  readonly attribute unsigned short state;
+  const unsigned short STATE_CLOSED = 0;
+  const unsigned short STATE_LOADING = 1;
+  const unsigned short STATE_OPENED = 2;
+
+  /**
+   * This indicates whether this node "may" have children, and can be used
+   * when the container is open or closed. When the container is closed, it
+   * will give you an exact answer if the node can easily be populated (for
+   * example, a bookmark folder). If not (for example, a complex history query),
+   * it will return true. When the container is open, it will always be
+   * accurate. It is intended to be used to see if we should draw the "+" next
+   * to a tree item.
+   */
+  readonly attribute boolean hasChildren;
+
+  /**
+   * This gives you the children of the nodes. It is preferrable to use this
+   * interface over the array one, since it avoids creating an nsIArray object
+   * and the interface is already the correct type.
+   *
+   * @throws NS_ERROR_NOT_AVAILABLE if containerOpen is false.
+   */
+  readonly attribute unsigned long childCount;
+  nsINavHistoryResultNode getChild(in unsigned long aIndex);
+
+  /**
+   * Get the index of a direct child in this container.
+   *
+   * @param aNode
+   *        a result node.
+   *
+   * @return aNode's index in this container.
+   * @throws NS_ERROR_NOT_AVAILABLE if containerOpen is false.
+   * @throws NS_ERROR_INVALID_ARG if aNode isn't a direct child of this
+   * container.
+   */
+  unsigned long getChildIndex(in nsINavHistoryResultNode aNode);
+};
+
+
+/**
+ * Used for places queries and as a base for bookmark folders.
+ *
+ * Note that if you request places to *not* be expanded in the options that
+ * generated this node, this item will report it has no children and never try
+ * to populate itself.
+ */
+[scriptable, uuid(62817759-4FEE-44A3-B58C-3E2F5AFC9D0A)]
+interface nsINavHistoryQueryResultNode : nsINavHistoryContainerResultNode
+{
+  /**
+   * Get the query which builds this node's children.
+   * Only valid for RESULT_TYPE_QUERY nodes.
+   */
+  readonly attribute nsINavHistoryQuery query;
+
+  /**
+   * Get the options which group this node's children.
+   * Only valid for RESULT_TYPE_QUERY nodes.
+   */
+  readonly attribute nsINavHistoryQueryOptions queryOptions;
+
+  /**
+   * For both simple folder queries and folder shortcut queries, this is set to
+   * the concrete itemId of the folder (i.e. for folder shortcuts it's the
+   * target folder id).  Otherwise, this is set to -1.
+   */
+  readonly attribute long long folderItemId;
+
+  /**
+   * For both simple folder queries and folder shortcut queries, this is set to
+   * the concrete guid of the folder (i.e. for folder shortcuts it's the target
+   * folder guid). Otherwise, this is set to an empty string.
+   */
+  readonly attribute ACString targetFolderGuid;
+};
+
+
+/**
+ * Allows clients to observe what is happening to a result as it updates itself
+ * according to history and bookmark system events. Register this observer on a
+ * result using nsINavHistoryResult::addObserver.
+ */
+[scriptable, uuid(f62d8b6b-3c4e-4a9f-a897-db605d0b7a0f)]
+interface nsINavHistoryResultObserver : nsISupports
+{
+  /**
+   * Whether the observer is interested into history details changes.
+   * Those include visits additions and removals. If the observer doesn't
+   * provide this attribute, it will default to false.
+   * In practice, the observer won't receive nodeHistoryDetailsChanged.
+   * Note: this is only read when the observer is added, it cannot be changed
+   * dynamically.
+   */
+  readonly attribute boolean skipHistoryDetailsNotifications;
+
+  /**
+   * Called when 'aItem' is inserted into 'aParent' at index 'aNewIndex'.
+   * The item previously at index (if any) and everything below it will have
+   * been shifted down by one. The item may be a container or a leaf.
+   */
+  void nodeInserted(in nsINavHistoryContainerResultNode aParent,
+                    in nsINavHistoryResultNode aNode,
+                    in unsigned long aNewIndex);
+
+  /**
+   * Called whan 'aItem' is removed from 'aParent' at 'aOldIndex'. The item
+   * may be a container or a leaf. This function will be called after the item
+   * has been removed from its parent list, but before anything else (including
+   * NULLing out the item's parent) has happened.
+   */
+  void nodeRemoved(in nsINavHistoryContainerResultNode aParent,
+                   in nsINavHistoryResultNode aItem,
+                   in unsigned long aOldIndex);
+
+  /**
+   * Called whan 'aItem' is moved from 'aOldParent' at 'aOldIndex' to
+   * aNewParent at aNewIndex. The item may be a container or a leaf.
+   *
+   * XXX: at the moment, this method is called only when an item is moved
+   * within the same container. When an item is moved between containers,
+   * a new node is created for the item, and the itemRemoved/itemAdded methods
+   * are used.
+   */
+  void nodeMoved(in nsINavHistoryResultNode aNode,
+                 in nsINavHistoryContainerResultNode aOldParent,
+                 in unsigned long aOldIndex,
+                 in nsINavHistoryContainerResultNode aNewParent,
+                 in unsigned long aNewIndex);
+
+  /**
+   * Called right after aNode's title has changed.
+   *
+   * @param aNode
+   *        a result node
+   * @param aNewTitle
+   *        the new title
+   */
+  void nodeTitleChanged(in nsINavHistoryResultNode aNode,
+                        in AUTF8String aNewTitle);
+
+  /**
+   * Called right after aNode's uri property has changed.
+   *
+   * @param aNode
+   *        a result node
+   * @param aNewURI
+   *        the old uri
+   */
+  void nodeURIChanged(in nsINavHistoryResultNode aNode,
+                      in AUTF8String aOldURI);
+
+  /**
+   * Called right after aNode's icon property has changed.
+   *
+   * @param aNode
+   *        a result node
+   *
+   * @note: The new icon is accessible through aNode.icon.
+   */
+  void nodeIconChanged(in nsINavHistoryResultNode aNode);
+
+  /**
+   * Called right after aNode's time property or accessCount property, or both,
+   * have changed.
+   *
+   * @param aNode
+   *        a uri result node
+   * @param aOldVisitDate
+   *        the old visit date
+   * @param aOldAccessCount
+   *        the old access-count
+   */
+  void nodeHistoryDetailsChanged(in nsINavHistoryResultNode aNode,
+                                 in PRTime aOldVisitDate,
+                                 in unsigned long aOldAccessCount);
+
+  /**
+   * Called when the tags set on the uri represented by aNode have changed.
+   *
+   * @param aNode
+   *        a uri result node
+   *
+   * @note: The new tags list is accessible through aNode.tags.
+   */
+  void nodeTagsChanged(in nsINavHistoryResultNode aNode);
+
+  /**
+   * Called right after the aNode's keyword property has changed.
+   *
+   * @param aNode
+   *        a uri result node
+   * @param aNewKeyword
+   *        the new keyword
+   */
+  void nodeKeywordChanged(in nsINavHistoryResultNode aNode,
+                          in AUTF8String aNewKeyword);
+
+  /**
+   * Called right after aNode's dateAdded property has changed.
+   *
+   * @param aNode
+   *        a result node
+   * @param aNewValue
+   *        the new value of the dateAdded property
+   */
+  void nodeDateAddedChanged(in nsINavHistoryResultNode aNode,
+                            in PRTime aNewValue);
+
+  /**
+   * Called right after aNode's dateModified property has changed.
+   *
+   * @param aNode
+   *        a result node
+   * @param aNewValue
+   *        the new value of the dateModified property
+   */
+  void nodeLastModifiedChanged(in nsINavHistoryResultNode aNode,
+                               in PRTime aNewValue);
+
+  /**
+   * Called after a container changes state.
+   *
+   * @param aContainerNode
+   *        The container that has changed state.
+   * @param aOldState
+   *        The state that aContainerNode has transitioned out of.
+   * @param aNewState
+   *        The state that aContainerNode has transitioned into.
+   */
+  void containerStateChanged(in nsINavHistoryContainerResultNode aContainerNode,
+                             in unsigned long aOldState,
+                             in unsigned long aNewState);
+
+  /**
+   * Called when something significant has happened within the container. The
+   * contents of the container should be re-built.
+   *
+   * @param aContainerNode
+   *        the container node to invalidate
+   */
+  void invalidateContainer(in nsINavHistoryContainerResultNode aContainerNode);
+
+  /**
+   * This is called to indicate to the UI that the sort has changed to the
+   * given mode. For trees, for example, this would update the column headers
+   * to reflect the sorting. For many other types of views, this won't be
+   * applicable.
+   *
+   * @param sortingMode  One of nsINavHistoryQueryOptions.SORT_BY_* that
+   *                     indicates the new sorting mode.
+   *
+   * This only is expected to update the sorting UI. invalidateAll() will also
+   * get called if the sorting changes to update everything.
+   */
+  void sortingChanged(in unsigned short sortingMode);
+
+  /**
+   * This is called to indicate that a batch operation is about to start or end.
+   * The observer could want to disable some events or updates during batches,
+   * since multiple operations are packed in a short time.
+   * For example treeviews could temporarily suppress select notifications.
+   *
+   * @param aToggleMode
+   *        true if a batch is starting, false if it's ending.
+   */
+  void batching(in boolean aToggleMode);
+
+  /**
+   * Called by the result when this observer is added.
+   */
+  attribute nsINavHistoryResult result;
+};
+
+
+/**
+ * The result of a history/bookmark query.
+ */
+[scriptable, uuid(c2229ce3-2159-4001-859c-7013c52f7619)]
+interface nsINavHistoryResult : nsISupports
+{
+  /**
+   * Sorts all nodes recursively by the given parameter, one of
+   * nsINavHistoryQueryOptions.SORT_BY_*  This will update the corresponding
+   * options for this result, so that re-using the current options/queries will
+   * always give you the current view.
+   */
+  attribute unsigned short sortingMode;
+
+  /**
+   * Whether or not notifications on result changes are suppressed.
+   * Initially set to false.
+   *
+   * Use this to avoid flickering and to improve performance when you
+   * do temporary changes to the result structure (e.g. when searching for a
+   * node recursively).
+   */
+  attribute boolean suppressNotifications;
+
+  /**
+   * Adds an observer for changes done in the result.
+   *
+   * @param aObserver
+   *        a result observer.
+   * @param aOwnsWeak
+   *        If false, the result will keep an owning reference to the observer,
+   *        which must be removed using removeObserver.
+   *        If true, the result will keep a weak reference to the observer, which
+   *        must implement nsISupportsWeakReference.
+   *
+   * @see nsINavHistoryResultObserver
+   */
+  void addObserver(in nsINavHistoryResultObserver aObserver,
+                   [optional] in boolean aOwnsWeak);
+
+  /**
+   * Removes an observer that was added by addObserver.
+   *
+   * @param aObserver
+   *        a result observer that was added by addObserver.
+   */
+  void removeObserver(in nsINavHistoryResultObserver aObserver);
+
+  /**
+   * This is the root of the results. Remember that you need to open all
+   * containers for their contents to be valid.
+   *
+   * When a result goes out of scope it will continue to observe changes till
+   * it is cycle collected.  While the result waits to be collected it will stay
+   * in memory, and continue to update itself, potentially causing unwanted
+   * additional work.  When you close the root node the result will stop
+   * observing changes, so it is good practice to close the root node when you
+   * are done with a result, since that will avoid unwanted performance hits.
+   */
+  readonly attribute nsINavHistoryContainerResultNode root;
+
+  /**
+   * Notifies you that a bunch of things are about to change, don't do any
+   * heavy-duty processing until onEndUpdateBatch is called.
+   */
+  void onBeginUpdateBatch();
+
+  /**
+   * Notifies you that we are done doing a bunch of things and you should go
+   * ahead and update UI, etc.
+   */
+  void onEndUpdateBatch();
+};
+
+
+/**
+ * This object encapsulates all the query parameters you're likely to need
+ * when building up history UI. All parameters are ANDed together.
+ *
+ * This is not intended to be a super-general query mechanism. This was designed
+ * so that most queries can be done in only one SQL query. This is important
+ * because, if the user has their profile on a networked drive, query latency
+ * can be non-negligible.
+ */
+
+[scriptable, uuid(dc87ae79-22f1-4dcf-975b-852b01d210cb)]
+interface nsINavHistoryQuery : nsISupports
+{
+  /**
+   * Time range for results (INCLUSIVE). The *TimeReference is one of the
+   * constants TIME_RELATIVE_* which indicates how to interpret the
+   * corresponding time value.
+   *   TIME_RELATIVE_EPOCH (default):
+   *     The time is relative to Jan 1 1970 GMT, (this is a normal PRTime)
+   *   TIME_RELATIVE_TODAY:
+   *     The time is relative to this morning at midnight. Normally used for
+   *     queries relative to today. For example, a "past week" query would be
+   *     today-6 days -> today+1 day
+   *   TIME_RELATIVE_NOW:
+   *     The time is relative to right now.
+   *
+   * Note: PRTime is in MICROseconds since 1 Jan 1970. Javascript date objects
+   * are expressed in MILLIseconds since 1 Jan 1970.
+   *
+   * As a special case, a 0 time relative to TIME_RELATIVE_EPOCH indicates that
+   * the time is not part of the query. This is the default, so an empty query
+   * will match any time. The has* functions return whether the corresponding
+   * time is considered.
+   *
+   * You can read absolute*Time to get the time value that the currently loaded
+   * reference points + offset resolve to.
+   */
+  const unsigned long TIME_RELATIVE_EPOCH = 0;
+  const unsigned long TIME_RELATIVE_TODAY = 1;
+  const unsigned long TIME_RELATIVE_NOW = 2;
+
+  attribute PRTime beginTime;
+  attribute unsigned long beginTimeReference;
+  readonly attribute boolean hasBeginTime;
+  readonly attribute PRTime absoluteBeginTime;
+
+  attribute PRTime endTime;
+  attribute unsigned long endTimeReference;
+  readonly attribute boolean hasEndTime;
+  readonly attribute PRTime absoluteEndTime;
+
+  /**
+   * Text search terms.
+   */
+  attribute AString searchTerms;
+  readonly attribute boolean hasSearchTerms;
+
+  /**
+   * Set lower or upper limits for how many times an item has been
+   * visited.  The default is -1, and in that case all items are
+   * matched regardless of their visit count.
+   */
+  attribute long minVisits;
+  attribute long maxVisits;
+
+  /**
+   * When the set of transitions is nonempty, results are limited to pages which
+   * have at least one visit for each of the transition types.
+   * @note: For searching on more than one transition this can be very slow.
+   *
+   * Limit results to the specified list of transition types.
+   */
+  void setTransitions(in Array<unsigned long> transitions);
+
+  /**
+   * Get the transitions set for this query.
+   */
+  Array<unsigned long> getTransitions();
+
+  /**
+   * Get the count of the set query transitions.
+   */
+  readonly attribute unsigned long transitionCount;
+
+  /**
+   * This controls the meaning of 'domain', and whether it is an exact match
+   * 'domainIsHost' = true, or hierarchical (= false).
+   */
+  attribute boolean domainIsHost;
+
+  /**
+   * This is the host or domain name (controlled by domainIsHost). When
+   * domainIsHost, domain only does exact matching on host names. Otherwise,
+   * it will return anything whose host name ends in 'domain'.
+   *
+   * This one is a little different than most. Setting it to an empty string
+   * is a real query and will match any URI that has no host name (local files
+   * and such). Set this to NULL (in C++ use SetIsVoid) if you don't want
+   * domain matching.
+   */
+  attribute AUTF8String domain;
+  readonly attribute boolean hasDomain;
+
+  /**
+   * This is a URI to match, to, for example, find out every time you visited
+   * a given URI. This is an exact match.
+   */
+  attribute nsIURI uri;
+  readonly attribute boolean hasUri;
+
+  /**
+   * Limit results to items that are tagged with all of the given tags.  This
+   * attribute must be set to an array of strings.  When called as a getter it
+   * will return an array of strings sorted ascending in lexicographical order.
+   * The array may be empty in either case.  Duplicate tags may be specified
+   * when setting the attribute, but the getter returns only unique tags.
+   */
+  attribute nsIVariant tags;
+
+  /**
+   * If 'tagsAreNot' is true, the results are instead limited to items that
+   * are not tagged with any of the given tags.  This attribute is used in
+   * conjunction with the 'tags' attribute.
+   */
+  attribute boolean tagsAreNot;
+
+  /**
+   * Limit results to items that are in all of the given folders.
+   */
+  Array<ACString> getParents();
+  readonly attribute unsigned long parentCount;
+
+  /**
+   * This is not recursive so results will be returned from the first level of
+   * that folder.
+   */
+  void setParents(in Array<ACString> aGuids);
+
+  /**
+   * Creates a new query item with the same parameters of this one.
+   */
+  nsINavHistoryQuery clone();
+};
+
+/**
+ * This object represents the global options for executing a query.
+ */
+[scriptable, uuid(8198dfa7-8061-4766-95cb-fa86b3c00a47)]
+interface nsINavHistoryQueryOptions : nsISupports
+{
+  /**
+   * You can ask for the results to be pre-sorted. Since the DB has indices
+   * of many items, it can produce sorted results almost for free. These should
+   * be self-explanatory.
+   *
+   * Note: re-sorting is slower, as is sorting by title or when you have a
+   * host name.
+   *
+   * For bookmark items, SORT_BY_NONE means sort by the natural bookmark order.
+   */
+  const unsigned short SORT_BY_NONE = 0;
+  const unsigned short SORT_BY_TITLE_ASCENDING = 1;
+  const unsigned short SORT_BY_TITLE_DESCENDING = 2;
+  const unsigned short SORT_BY_DATE_ASCENDING = 3;
+  const unsigned short SORT_BY_DATE_DESCENDING = 4;
+  const unsigned short SORT_BY_URI_ASCENDING = 5;
+  const unsigned short SORT_BY_URI_DESCENDING = 6;
+  const unsigned short SORT_BY_VISITCOUNT_ASCENDING = 7;
+  const unsigned short SORT_BY_VISITCOUNT_DESCENDING = 8;
+  const unsigned short SORT_BY_DATEADDED_ASCENDING = 11;
+  const unsigned short SORT_BY_DATEADDED_DESCENDING = 12;
+  const unsigned short SORT_BY_LASTMODIFIED_ASCENDING = 13;
+  const unsigned short SORT_BY_LASTMODIFIED_DESCENDING = 14;
+  const unsigned short SORT_BY_TAGS_ASCENDING = 17;
+  const unsigned short SORT_BY_TAGS_DESCENDING = 18;
+  const unsigned short SORT_BY_FRECENCY_ASCENDING = 21;
+  const unsigned short SORT_BY_FRECENCY_DESCENDING = 22;
+
+  /**
+   * "URI" results, one for each URI visited in the range. Individual result
+   * nodes will be of type "URI".
+   */
+  const unsigned short RESULTS_AS_URI = 0;
+
+  /**
+   * "Visit" results, with one for each time a page was visited (this will
+   * often give you multiple results for one URI). Individual result nodes will
+   * have type "Visit"
+   *
+   * @note This result type is only supported by QUERY_TYPE_HISTORY.
+   */
+  const unsigned short RESULTS_AS_VISIT = 1;
+
+  /**
+   * This returns query nodes for each predefined date range where we
+   * had visits. The node contains information how to load its content:
+   * - visits for the given date range will be loaded.
+   *
+   * @note This result type is only supported by QUERY_TYPE_HISTORY.
+   */
+  const unsigned short RESULTS_AS_DATE_QUERY = 3;
+
+  /**
+   * This returns nsINavHistoryQueryResultNode nodes for each site where we
+   * have visits. The node contains information how to load its content:
+   * - last visit for each url in the given host will be loaded.
+   *
+   * @note This result type is only supported by QUERY_TYPE_HISTORY.
+   */
+  const unsigned short RESULTS_AS_SITE_QUERY = 4;
+
+  /**
+   * This returns nsINavHistoryQueryResultNode nodes for each day where we
+   * have visits. The node contains information how to load its content:
+   * - list of hosts visited in the given period will be loaded.
+   *
+   * @note This result type is only supported by QUERY_TYPE_HISTORY.
+   */
+  const unsigned short RESULTS_AS_DATE_SITE_QUERY = 5;
+
+  /**
+   * This returns nsINavHistoryQueryResultNode nodes for each tag.
+   * The node contains information how to load its content:
+   * - list of bookmarks with the given tag will be loaded.
+   *
+   * @note Setting this resultType will force queryType to QUERY_TYPE_BOOKMARKS.
+   */
+  const unsigned short RESULTS_AS_TAGS_ROOT = 6;
+
+  /**
+   * DEPRECATED: This exists for Sync and also to avoid reusing this number.
+   */
+  const unsigned short RESULTS_AS_TAG_CONTENTS = 7;
+
+  /**
+   * This returns nsINavHistoryQueryResultNode nodes for each top-level bookmark
+   * root.
+   *
+   * @note Setting this resultType will force queryType to QUERY_TYPE_BOOKMARKS.
+   */
+  const unsigned short RESULTS_AS_ROOTS_QUERY = 8;
+
+  /**
+   * This returns nsINavHistoryQueryResultNode for each left-pane root.
+   */
+  const unsigned short RESULTS_AS_LEFT_PANE_QUERY = 9;
+
+  /**
+   * The sorting mode to be used for this query.
+   * mode is one of SORT_BY_*
+   */
+  attribute unsigned short sortingMode;
+
+  /**
+   * Sets the result type. One of RESULT_TYPE_* which includes how URIs are
+   * represented.
+   */
+  attribute unsigned short resultType;
+
+  /**
+   * This option excludes all URIs and separators from a bookmarks query.
+   * This would be used if you just wanted a list of bookmark folders and
+   * queries (such as the left pane of the places page).
+   * Defaults to false.
+   */
+  attribute boolean excludeItems;
+
+  /**
+   * Set to true to exclude queries ("place:" URIs) from the query results.
+   * Simple folder queries (bookmark folder symlinks) will still be included.
+   * Defaults to false.
+   */
+  attribute boolean excludeQueries;
+
+  /**
+   * When set, allows items with "place:" URIs to appear as containers,
+   * with the container's contents filled in from the stored query.
+   * If not set, these will appear as normal items. Doesn't do anything if
+   * excludeQueries is set. Defaults to false.
+   *
+   * Note that this has no effect on folder links, which are place: URIs
+   * returned by nsINavBookmarkService.GetFolderURI. These are always expanded
+   * and will appear as bookmark folders.
+   */
+  attribute boolean expandQueries;
+
+  /**
+   * Some pages in history are marked "hidden" and thus don't appear by default
+   * in queries.  These include automatic framed visits and redirects.  Setting
+   * this attribute will return all pages, even hidden ones.  Does nothing for
+   * bookmark queries. Defaults to false.
+   */
+  attribute boolean includeHidden;
+
+  /**
+   * This is the maximum number of results that you want. The query is executed,
+   * the results are sorted, and then the top 'maxResults' results are taken
+   * and returned. Set to 0 (the default) to get all results.
+   *
+   * THIS DOES NOT WORK IN CONJUNCTION WITH SORTING BY TITLE. This is because
+   * sorting by title requires us to sort after using locale-sensetive sorting
+   * (as opposed to letting the database do it for us).
+   *
+   * Instead, we get the result ordered by date, pick the maxResult most recent
+   * ones, and THEN sort by title.
+   */
+  attribute unsigned long maxResults;
+
+  const unsigned short QUERY_TYPE_HISTORY = 0;
+  const unsigned short QUERY_TYPE_BOOKMARKS = 1;
+
+  /**
+   * The type of search to use when querying the DB; This attribute is only
+   * honored by query nodes. It is silently ignored for simple folder queries.
+   */
+  attribute unsigned short queryType;
+
+  /**
+   * When this is true, the root container node generated by these options and
+   * its descendant containers will be opened asynchronously if they support it.
+   * This is false by default.
+   *
+   * @note Currently only bookmark folder containers support being opened
+   *       asynchronously.
+   */
+  attribute boolean asyncEnabled;
+
+  /**
+   * Creates a new options item with the same parameters of this one.
+   */
+  nsINavHistoryQueryOptions clone();
+};
+
+[scriptable, uuid(20c974ff-ee16-4828-9326-1b7c9e036622)]
+interface nsINavHistoryService : nsISupports
+{
+  // The current database schema version.
+  // To migrate to a new version bump this, add a MigrateVXXUp function to
+  // Database.cpp/h, and a test into tests/migration/
+  const unsigned long DATABASE_SCHEMA_VERSION = 75;
+
+  /**
+   * System Notifications:
+   *
+   * places-init-complete - Sent once the History service is completely
+   *                        initialized successfully.
+   * places-database-locked - Sent if initialization of the History service
+   *                          failed due to the inability to open the places.sqlite
+   *                          for access reasons.
+   */
+
+  /**
+   * This transition type means the user followed a link and got a new toplevel
+   * window.
+   */
+  const unsigned long TRANSITION_LINK = 1;
+
+  /**
+   * This transition type means that the user typed the page's URL in the
+   * URL bar or selected it from URL bar autocomplete results, clicked on
+   * it from a history query (from the History sidebar, History menu,
+   * or history query in the personal toolbar or Places organizer.
+   */
+  const unsigned long TRANSITION_TYPED = 2;
+
+  /**
+   * This transition is set when the user followed a bookmark to get to the
+   * page.
+   */
+  const unsigned long TRANSITION_BOOKMARK = 3;
+
+  /**
+   * This transition type is set when some inner content is loaded. This is
+   * true of all images on a page, and the contents of the iframe. It is also
+   * true of any content in a frame if the user did not explicitly follow
+   * a link to get there.
+   */
+  const unsigned long TRANSITION_EMBED = 4;
+
+  /**
+   * Set when the transition was a permanent redirect.
+   */
+  const unsigned long TRANSITION_REDIRECT_PERMANENT = 5;
+
+  /**
+   * Set when the transition was a temporary redirect.
+   */
+  const unsigned long TRANSITION_REDIRECT_TEMPORARY = 6;
+
+  /**
+   * Set when the transition is a download.
+   */
+  const unsigned long TRANSITION_DOWNLOAD = 7;
+
+  /**
+   * This transition type means the user followed a link and got a visit in
+   * a frame.
+   */
+  const unsigned long TRANSITION_FRAMED_LINK = 8;
+
+  /**
+   * This transition type means the page has been reloaded.
+   */
+  const unsigned long TRANSITION_RELOAD = 9;
+
+  /**
+   * Set when database is coherent
+   */
+  const unsigned short DATABASE_STATUS_OK = 0;
+
+  /**
+   * Set when database did not exist and we created a new one.
+   */
+  const unsigned short DATABASE_STATUS_CREATE = 1;
+
+  /**
+   * Set when database was corrupt and we replaced it with a new one.
+   */
+  const unsigned short DATABASE_STATUS_CORRUPT = 2;
+
+  /**
+   * Set when database schema has been upgraded.
+   */
+  const unsigned short DATABASE_STATUS_UPGRADED = 3;
+
+  /**
+   * Set when database couldn't be opened.
+   */
+  const unsigned short DATABASE_STATUS_LOCKED = 4;
+
+  /**
+   * Insert this value into moz_historyvisits if the visit source is organic.
+   */
+  const unsigned short VISIT_SOURCE_ORGANIC = 0;
+
+  /**
+   * Insert this value into moz_historyvisits if the visit source is sponsored.
+   */
+  const unsigned short VISIT_SOURCE_SPONSORED = 1;
+
+  /**
+   * Insert this value into moz_historyvisits if the visit source is bookmarked.
+   */
+  const unsigned short VISIT_SOURCE_BOOKMARKED = 2;
+
+  /**
+   * Insert this value into moz_historyvisits if the visit source is searched.
+   */
+  const unsigned short VISIT_SOURCE_SEARCHED = 3;
+
+  /**
+   * Returns the current database status
+   */
+  readonly attribute unsigned short databaseStatus;
+
+  /**
+   * This is just like markPageAsTyped (in nsIBrowserHistory, also implemented
+   * by the history service), but for bookmarks. It declares that the given URI
+   * is being opened as a result of following a bookmark. If this URI is loaded
+   * soon after this message has been received, that transition will be marked
+   * as following a bookmark.
+   */
+  void markPageAsFollowedBookmark(in nsIURI aURI);
+
+  /**
+   * Designates the url as having been explicitly typed in by the user.
+   *
+   * @param aURI
+   *        URI of the page to be marked.
+   */
+  void markPageAsTyped(in nsIURI aURI);
+
+  /**
+   * Designates the url as coming from a link explicitly followed by
+   * the user (for example by clicking on it).
+   *
+   * @param aURI
+   *        URI of the page to be marked.
+   */
+  void markPageAsFollowedLink(in nsIURI aURI);
+
+  /**
+   * Returns true if this URI would be added to the history. You don't have to
+   * worry about calling this, adding a visit will always check before
+   * actually adding the page. This function is public because some components
+   * may want to check if this page would go in the history (i.e. for
+   * annotations).
+   */
+  boolean canAddURI(in nsIURI aURI);
+
+  /**
+   * This returns a new query object that you can pass to executeQuer[y/ies].
+   * It will be initialized to all empty (so using it will give you all history).
+   */
+  nsINavHistoryQuery getNewQuery();
+
+  /**
+   * This returns a new options object that you can pass to executeQuer[y/ies]
+   * after setting the desired options.
+   */
+  nsINavHistoryQueryOptions getNewQueryOptions();
+
+  /**
+   * Executes a single query.
+   */
+  nsINavHistoryResult executeQuery(in nsINavHistoryQuery aQuery,
+                                   in nsINavHistoryQueryOptions options);
+
+  /**
+   * Converts a query URI-like string to a query object.
+   */
+  void queryStringToQuery(in AUTF8String aQueryString,
+                          out nsINavHistoryQuery aQuery,
+                          out nsINavHistoryQueryOptions options);
+
+  /**
+   * Converts a query into an equivalent string that can be persisted. Inverse
+   * of queryStringToQuery()
+   */
+  AUTF8String queryToQueryString(in nsINavHistoryQuery aQuery,
+                                 in nsINavHistoryQueryOptions options);
+
+  /**
+   * True if history is disabled. currently,
+   * history is disabled if the places.history.enabled pref is false.
+   */
+  readonly attribute boolean historyDisabled;
+
+  /**
+   * Generate a guid.
+   * Guids can be used for any places purposes (history, bookmarks, etc.)
+   * Returns null if the generation of the guid failed.
+   */
+  ACString makeGuid();
+
+  /**
+   * Returns a 48-bit hash for a URI spec.
+   *
+   * @param aSpec
+   *        The URI spec to hash.
+   * @param aMode
+   *        The hash mode: `""` (default), `"prefix_lo"`, or `"prefix_hi"`.
+   */
+  unsigned long long hashURL(in ACString aSpec, [optional] in ACString aMode);
+
+  /**
+   * Whether frecency is in the process of being decayed. The value can also
+   * be read through the is_frecency_decaying() SQL function exposed by Places
+   * database connections.
+   */
+  attribute boolean isFrecencyDecaying;
+
+  /**
+   * This is set to true when a frecency is invalidated and set back to false
+   * when all the outdated values have been recalculated.
+   */
+  attribute boolean shouldStartFrecencyRecalculation;
+
+  /**
+   * The database connection used by Places.
+   */
+  readonly attribute mozIStorageConnection DBConnection;
+
+  /**
+   * Asynchronously executes the statement created from a query.
+   *
+   * @see nsINavHistoryService::executeQuery
+   * @note THIS IS A TEMPORARY API.  Don't rely on it, since it will be replaced
+   *       in future versions by a real async querying API.
+   * @note Results obtained from this method differ from results obtained from
+   *       executeQuery, because there is additional filtering and sorting
+   *       done by the latter.  Thus you should use executeQuery, unless you
+   *       are absolutely sure that the returned results are fine for
+   *       your use-case.
+   */
+  mozIStoragePendingStatement asyncExecuteLegacyQuery(
+    in nsINavHistoryQuery aQuery,
+    in nsINavHistoryQueryOptions aOptions,
+    in mozIStorageStatementCallback aCallback);
+
+  /**
+   * Hook for clients who need to perform actions during/by the end of
+   * the shutdown of the database.
+   * May be null if it's too late to get one.
+   */
+  readonly attribute nsIAsyncShutdownClient shutdownClient;
+
+  /**
+   * Hook for internal clients who need to perform actions just before the
+   * connection gets closed.
+   * May be null if it's too late to get one.
+   */
+  readonly attribute nsIAsyncShutdownClient connectionShutdownClient;
+};
diff --git a/toolkit/components/places/nsIPlacesPreviewsHelperService.idl b/toolkit/components/places/nsIPlacesPreviewsHelperService.idl
new file mode 100644
index 0000000000..7293532ffb
--- /dev/null
+++ b/toolkit/components/places/nsIPlacesPreviewsHelperService.idl
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/**
+ * A service which returns information about file paths where the
+ * previews for URLs are stored. These previews are used by the
+ * moz-page-thumb protocol
+ */
+
+[scriptable, uuid(bd0a4d3b-ff26-4d4d-9a62-a513e1c1bf92)]
+interface nsIPlacesPreviewsHelperService : nsISupports
+{
+  /**
+   * Returns the full file path containing the screenshot for a given URL
+   */
+  AString getFilePathForURL(in AString aURL);
+};
diff --git a/toolkit/components/places/nsITaggingService.idl b/toolkit/components/places/nsITaggingService.idl
new file mode 100644
index 0000000000..acda63b583
--- /dev/null
+++ b/toolkit/components/places/nsITaggingService.idl
@@ -0,0 +1,66 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+interface nsIVariant;
+
+[scriptable, uuid(9759bd0e-78e2-4421-9ed1-c676e1af3513)]
+interface nsITaggingService : nsISupports
+{
+  /**
+   * Tags a URL with the given set of tags. Current tags set for the URL
+   * persist. Tags in aTags which are already set for the given URL are
+   * ignored.
+   *
+   * @param aURI
+   *        the URL to tag.
+   * @param aTags
+   *        Array of tags to set for the given URL.  Each element within the
+   *        array can be either a tag name (non-empty string) or a concrete
+   *        itemId of a tag container.
+   * @param [optional] aSource
+   *        A change source constant from nsINavBookmarksService::SOURCE_*.
+   *        Defaults to SOURCE_DEFAULT if omitted.
+   */
+  void tagURI(in nsIURI aURI,
+              in nsIVariant aTags,
+              [optional] in unsigned short aSource);
+
+  /**
+   * Removes tags from a URL. Tags from aTags which are not set for the
+   * given URL are ignored.
+   *
+   * @param aURI
+   *        the URL to un-tag.
+   * @param aTags
+   *        Array of tags to unset.  Pass null to remove all tags from the given
+   *        url.  Each element within the array can be either a tag name
+   *        (non-empty string) or a concrete itemId of a tag container.
+   * @param [optional] aSource
+   *        A change source constant from nsINavBookmarksService::SOURCE_*.
+   *        Defaults to SOURCE_DEFAULT if omitted.
+   */
+  void untagURI(in nsIURI aURI,
+                in nsIVariant aTags,
+                [optional] in unsigned short aSource);
+
+  /**
+   * Retrieves all tags set for the given URL.
+   *
+   * @param aURI
+   *        a URL.
+   * @returns array of tags (sorted by name).
+   */
+  Array<AString> getTagsForURI(in nsIURI aURI);
+
+};
+
+%{C++
+
+#define TAGGING_SERVICE_CID "@mozilla.org/browser/tagging-service;1"
+
+%}
diff --git a/toolkit/components/places/nsNavBookmarks.cpp b/toolkit/components/places/nsNavBookmarks.cpp
new file mode 100644
index 0000000000..b47c967706
--- /dev/null
+++ b/toolkit/components/places/nsNavBookmarks.cpp
@@ -0,0 +1,1799 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNavBookmarks.h"
+
+#include "nsNavHistory.h"
+#include "nsPlacesMacros.h"
+#include "Helpers.h"
+
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsITaggingService.h"
+#include "nsNetUtil.h"
+#include "nsIProtocolHandler.h"
+#include "nsIObserverService.h"
+#include "nsUnicharUtils.h"
+#include "nsPrintfCString.h"
+#include "nsQueryObject.h"
+#include "mozIStorageValueArray.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/storage.h"
+#include "mozilla/dom/PlacesBookmarkAddition.h"
+#include "mozilla/dom/PlacesBookmarkRemoved.h"
+#include "mozilla/dom/PlacesBookmarkTags.h"
+#include "mozilla/dom/PlacesBookmarkTime.h"
+#include "mozilla/dom/PlacesBookmarkTitle.h"
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/dom/PlacesVisit.h"
+
+using namespace mozilla;
+
+// These columns sit to the right of the kGetInfoIndex_* columns.
+const int32_t nsNavBookmarks::kGetChildrenIndex_Guid = 18;
+const int32_t nsNavBookmarks::kGetChildrenIndex_Position = 19;
+const int32_t nsNavBookmarks::kGetChildrenIndex_Type = 20;
+const int32_t nsNavBookmarks::kGetChildrenIndex_PlaceID = 21;
+const int32_t nsNavBookmarks::kGetChildrenIndex_SyncStatus = 22;
+
+using namespace mozilla::dom;
+using namespace mozilla::places;
+
+extern "C" {
+
+// Returns the total number of Sync changes recorded since Places startup for
+// all bookmarks. This function uses C linkage because it's called from the
+// Rust synced bookmarks mirror, on the storage thread. Using `get_service` to
+// access the bookmarks service from Rust trips a thread-safety assertion, so
+// we can't use `nsNavBookmarks::GetTotalSyncChanges`.
+int64_t NS_NavBookmarksTotalSyncChanges() {
+  return nsNavBookmarks::sTotalSyncChanges;
+}
+
+}  // extern "C"
+
+PLACES_FACTORY_SINGLETON_IMPLEMENTATION(nsNavBookmarks, gBookmarksService)
+
+namespace {
+
+// Returns the sync change counter increment for a change source constant.
+inline int64_t DetermineSyncChangeDelta(uint16_t aSource) {
+  return aSource == nsINavBookmarksService::SOURCE_SYNC ? 0 : 1;
+}
+
+// Returns the sync status for a new item inserted by a change source.
+inline int32_t DetermineInitialSyncStatus(uint16_t aSource) {
+  if (aSource == nsINavBookmarksService::SOURCE_SYNC) {
+    return nsINavBookmarksService::SYNC_STATUS_NORMAL;
+  }
+  if (aSource == nsINavBookmarksService::SOURCE_RESTORE_ON_STARTUP) {
+    return nsINavBookmarksService::SYNC_STATUS_UNKNOWN;
+  }
+  return nsINavBookmarksService::SYNC_STATUS_NEW;
+}
+
+// Indicates whether an item has been uploaded to the server and
+// needs a tombstone on deletion.
+inline bool NeedsTombstone(const BookmarkData& aBookmark) {
+  return aBookmark.syncStatus == nsINavBookmarksService::SYNC_STATUS_NORMAL;
+}
+
+inline nsresult GetTags(nsIURI* aURI, nsTArray<nsString>& aResult) {
+  nsresult rv;
+  nsCOMPtr<nsITaggingService> taggingService =
+      do_GetService("@mozilla.org/browser/tagging-service;1", &rv);
+
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return taggingService->GetTagsForURI(aURI, aResult);
+}
+
+}  // namespace
+
+nsNavBookmarks::nsNavBookmarks() : mCanNotify(false) {
+  NS_ASSERTION(!gBookmarksService,
+               "Attempting to create two instances of the service!");
+  gBookmarksService = this;
+}
+
+nsNavBookmarks::~nsNavBookmarks() {
+  NS_ASSERTION(gBookmarksService == this,
+               "Deleting a non-singleton instance of the service");
+  if (gBookmarksService == this) gBookmarksService = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsNavBookmarks, nsINavBookmarksService, nsIObserver,
+                  nsISupportsWeakReference)
+
+Atomic<int64_t> nsNavBookmarks::sLastInsertedItemId(0);
+
+void  // static
+nsNavBookmarks::StoreLastInsertedId(const nsACString& aTable,
+                                    const int64_t aLastInsertedId) {
+  MOZ_ASSERT(aTable.EqualsLiteral("moz_bookmarks"));
+  sLastInsertedItemId = aLastInsertedId;
+}
+
+Atomic<int64_t> nsNavBookmarks::sTotalSyncChanges(0);
+
+void  // static
+nsNavBookmarks::NoteSyncChange() {
+  sTotalSyncChanges++;
+}
+
+nsresult nsNavBookmarks::Init() {
+  mDB = Database::GetDatabase();
+  NS_ENSURE_STATE(mDB);
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    (void)os->AddObserver(this, TOPIC_PLACES_CONNECTION_CLOSED, true);
+  }
+
+  mCanNotify = true;
+
+  // DO NOT PUT STUFF HERE that can fail. See observer comment above.
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::AdjustIndices(int64_t aFolderId, int32_t aStartIndex,
+                                       int32_t aEndIndex, int32_t aDelta) {
+  NS_ASSERTION(
+      aStartIndex >= 0 && aEndIndex <= INT32_MAX && aStartIndex <= aEndIndex,
+      "Bad indices");
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET position = position + :delta "
+      "WHERE parent = :parent "
+      "AND position BETWEEN :from_index AND :to_index");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt32ByName("delta"_ns, aDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("parent"_ns, aFolderId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("from_index"_ns, aStartIndex);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("to_index"_ns, aEndIndex);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::AdjustSeparatorsSyncCounter(int64_t aFolderId,
+                                                     int32_t aStartIndex,
+                                                     int64_t aSyncChangeDelta) {
+  MOZ_ASSERT(aStartIndex >= 0, "Bad start position");
+  if (!aSyncChangeDelta) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET syncChangeCounter = syncChangeCounter + :delta "
+      "WHERE parent = :parent AND position >= :start_index "
+      "AND type = :item_type ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("delta"_ns, aSyncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("parent"_ns, aFolderId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("start_index"_ns, aStartIndex);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("item_type"_ns, TYPE_SEPARATOR);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::GetTagsFolder(int64_t* aRoot) {
+  int64_t id = mDB->GetTagsFolderId();
+  NS_ENSURE_TRUE(id > 0, NS_ERROR_UNEXPECTED);
+  *aRoot = id;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::GetTotalSyncChanges(int64_t* aTotalSyncChanges) {
+  *aTotalSyncChanges = sTotalSyncChanges;
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::InsertBookmarkInDB(
+    int64_t aPlaceId, enum ItemType aItemType, int64_t aParentId,
+    int32_t aIndex, const nsACString& aTitle, PRTime aDateAdded,
+    PRTime aLastModified, const nsACString& aParentGuid, int64_t aGrandParentId,
+    nsIURI* aURI, uint16_t aSource, int64_t* _itemId, nsACString& _guid) {
+  // Check for a valid itemId.
+  MOZ_ASSERT(_itemId && (*_itemId == -1 || *_itemId > 0));
+  // Check for a valid placeId.
+  MOZ_ASSERT(aPlaceId && (aPlaceId == -1 || aPlaceId > 0));
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "INSERT INTO moz_bookmarks "
+      "(id, fk, type, parent, position, title, "
+      "dateAdded, lastModified, guid, syncStatus, syncChangeCounter) "
+      "VALUES (:item_id, :page_id, :item_type, :parent, :item_index, "
+      ":item_title, :date_added, :last_modified, "
+      ":item_guid, :sync_status, :change_counter)");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv;
+  if (*_itemId != -1)
+    rv = stmt->BindInt64ByName("item_id"_ns, *_itemId);
+  else
+    rv = stmt->BindNullByName("item_id"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (aPlaceId != -1)
+    rv = stmt->BindInt64ByName("page_id"_ns, aPlaceId);
+  else
+    rv = stmt->BindNullByName("page_id"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->BindInt32ByName("item_type"_ns, aItemType);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("parent"_ns, aParentId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("item_index"_ns, aIndex);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (aTitle.IsEmpty())
+    rv = stmt->BindNullByName("item_title"_ns);
+  else
+    rv = stmt->BindUTF8StringByName("item_title"_ns, aTitle);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->BindInt64ByName("date_added"_ns, aDateAdded);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (aLastModified) {
+    rv = stmt->BindInt64ByName("last_modified"_ns, aLastModified);
+  } else {
+    rv = stmt->BindInt64ByName("last_modified"_ns, aDateAdded);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Could use IsEmpty because our callers check for GUID validity,
+  // but it doesn't hurt.
+  bool hasExistingGuid = _guid.Length() == 12;
+  if (hasExistingGuid) {
+    MOZ_ASSERT(IsValidGUID(_guid));
+    rv = stmt->BindUTF8StringByName("item_guid"_ns, _guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    nsAutoCString guid;
+    rv = GenerateGUID(guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindUTF8StringByName("item_guid"_ns, guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    _guid.Assign(guid);
+  }
+
+  int64_t syncChangeDelta = DetermineSyncChangeDelta(aSource);
+  rv = stmt->BindInt64ByName("change_counter"_ns, syncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  uint16_t syncStatus = DetermineInitialSyncStatus(aSource);
+  rv = stmt->BindInt32ByName("sync_status"_ns, syncStatus);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Remove stale tombstones if we're reinserting an item.
+  if (hasExistingGuid) {
+    rv = RemoveTombstone(_guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (*_itemId == -1) {
+    *_itemId = sLastInsertedItemId;
+  }
+
+  if (aParentId > 0) {
+    // Update last modified date of the ancestors.
+    // TODO (bug 408991): Doing this for all ancestors would be slow without a
+    //                    nested tree, so for now update only the parent.
+    rv = SetItemDateInternal(LAST_MODIFIED, syncChangeDelta, aParentId,
+                             aDateAdded);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+  bool isTagging = aGrandParentId == tagsRootId;
+  if (isTagging) {
+    // If we're tagging a bookmark, increment the change counter for all
+    // bookmarks with the URI.
+    rv = AddSyncChangesForBookmarksWithURI(aURI, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Mark all affected separators as changed
+  rv = AdjustSeparatorsSyncCounter(aParentId, aIndex + 1, syncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Add a cache entry since we know everything about this bookmark.
+  BookmarkData bookmark;
+  bookmark.id = *_itemId;
+  bookmark.guid.Assign(_guid);
+  if (!aTitle.IsEmpty()) {
+    bookmark.title.Assign(aTitle);
+  }
+  bookmark.position = aIndex;
+  bookmark.placeId = aPlaceId;
+  bookmark.parentId = aParentId;
+  bookmark.type = aItemType;
+  bookmark.dateAdded = aDateAdded;
+  if (aLastModified)
+    bookmark.lastModified = aLastModified;
+  else
+    bookmark.lastModified = aDateAdded;
+  if (aURI) {
+    rv = aURI->GetSpec(bookmark.url);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  bookmark.parentGuid = aParentGuid;
+  bookmark.grandParentId = aGrandParentId;
+  bookmark.syncStatus = syncStatus;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::InsertBookmark(int64_t aFolder, nsIURI* aURI, int32_t aIndex,
+                               const nsACString& aTitle,
+                               const nsACString& aGUID, uint16_t aSource,
+                               int64_t* aNewBookmarkId) {
+  NS_ENSURE_ARG(aURI);
+  NS_ENSURE_ARG_POINTER(aNewBookmarkId);
+  NS_ENSURE_ARG_MIN(aIndex, nsINavBookmarksService::DEFAULT_INDEX);
+
+  if (!aGUID.IsEmpty() && !IsValidGUID(aGUID)) return NS_ERROR_INVALID_ARG;
+
+  mozStorageTransaction transaction(mDB->MainConn(), false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+  int64_t placeId;
+  nsAutoCString placeGuid;
+  nsresult rv = history->GetOrCreateIdForPage(aURI, &placeId, placeGuid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Get the correct index for insertion.  This also ensures the parent exists.
+  int32_t index, folderCount;
+  int64_t grandParentId;
+  nsAutoCString folderGuid;
+  rv = FetchFolderInfo(aFolder, &folderCount, folderGuid, &grandParentId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (aIndex == nsINavBookmarksService::DEFAULT_INDEX ||
+      aIndex >= folderCount) {
+    index = folderCount;
+  } else {
+    index = aIndex;
+    // Create space for the insertion.
+    rv = AdjustIndices(aFolder, index, INT32_MAX, 1);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  *aNewBookmarkId = -1;
+  PRTime dateAdded = RoundedPRNow();
+  nsAutoCString guid(aGUID);
+  nsCString title;
+  TruncateTitle(aTitle, title);
+
+  rv = InsertBookmarkInDB(placeId, BOOKMARK, aFolder, index, title, dateAdded,
+                          0, folderGuid, grandParentId, aURI, aSource,
+                          aNewBookmarkId, guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!mCanNotify) {
+    return NS_OK;
+  }
+
+  Sequence<OwningNonNull<PlacesEvent>> notifications;
+  nsAutoCString utf8spec;
+  aURI->GetSpec(utf8spec);
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+
+  RefPtr<PlacesBookmarkAddition> bookmark = new PlacesBookmarkAddition();
+  bookmark->mItemType = TYPE_BOOKMARK;
+  bookmark->mId = *aNewBookmarkId;
+  bookmark->mParentId = aFolder;
+  bookmark->mIndex = index;
+  bookmark->mUrl.Assign(NS_ConvertUTF8toUTF16(utf8spec));
+  bookmark->mTitle.Assign(NS_ConvertUTF8toUTF16(title));
+  bookmark->mDateAdded = dateAdded / 1000;
+  bookmark->mGuid.Assign(guid);
+  bookmark->mParentGuid.Assign(folderGuid);
+  bookmark->mSource = aSource;
+  bookmark->mIsTagging = grandParentId == tagsRootId;
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT "
+      "  h.frecency, "
+      "  h.hidden, "
+      "  h.visit_count, "
+      "  h.last_visit_date, "
+      "  (SELECT group_concat(p.title ORDER BY p.title) "
+      "    FROM moz_bookmarks b "
+      "    JOIN moz_bookmarks p ON p.id = b.parent "
+      "    JOIN moz_bookmarks g ON g.id = p.parent "
+      "    WHERE g.guid = " SQL_QUOTE(TAGS_ROOT_GUID)
+      "      AND b.fk = h.id "
+      "  ) AS tags, "
+      "  t.guid, t.id, t.title "
+      "FROM moz_places h "
+      "LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(h.url) "
+      "WHERE h.id = :id");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+  rv = stmt->BindInt64ByName("id"_ns, placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool exists;
+  if (NS_SUCCEEDED(stmt->ExecuteStep(&exists)) && exists) {
+    int32_t frecency;
+    rv = stmt->GetInt32(0, &frecency);
+    NS_ENSURE_SUCCESS(rv, rv);
+    bookmark->mFrecency = frecency;
+    int32_t hidden;
+    rv = stmt->GetInt32(1, &hidden);
+    NS_ENSURE_SUCCESS(rv, rv);
+    bookmark->mHidden = !!hidden;
+    int32_t visitCount;
+    rv = stmt->GetInt32(2, &visitCount);
+    NS_ENSURE_SUCCESS(rv, rv);
+    bookmark->mVisitCount = visitCount;
+
+    bool isLastVisitDateNull;
+    rv = stmt->GetIsNull(3, &isLastVisitDateNull);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (isLastVisitDateNull) {
+      bookmark->mLastVisitDate.SetNull();
+    } else {
+      int64_t lastVisitDate;
+      rv = stmt->GetInt64(3, &lastVisitDate);
+      NS_ENSURE_SUCCESS(rv, rv);
+      bookmark->mLastVisitDate = lastVisitDate;
+    }
+
+    nsString tags;
+    rv = stmt->GetString(4, tags);
+    NS_ENSURE_SUCCESS(rv, rv);
+    bookmark->mTags.Assign(tags);
+
+    bool isTargetFolderNull;
+    rv = stmt->GetIsNull(5, &isTargetFolderNull);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!isTargetFolderNull) {
+      nsCString targetFolderGuid;
+      rv = stmt->GetUTF8String(5, targetFolderGuid);
+      NS_ENSURE_SUCCESS(rv, rv);
+      bookmark->mTargetFolderGuid.Assign(targetFolderGuid);
+
+      int64_t targetFolderItemId = -1;
+      rv = stmt->GetInt64(6, &targetFolderItemId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      bookmark->mTargetFolderItemId = targetFolderItemId;
+
+      nsString targetFolderTitle;
+      rv = stmt->GetString(7, targetFolderTitle);
+      NS_ENSURE_SUCCESS(rv, rv);
+      bookmark->mTargetFolderTitle.Assign(targetFolderTitle);
+    } else {
+      bookmark->mTargetFolderGuid.SetIsVoid(true);
+      bookmark->mTargetFolderItemId = -1;
+      bookmark->mTargetFolderTitle.SetIsVoid(true);
+    }
+  } else {
+    MOZ_ASSERT(false);
+    bookmark->mTags.SetIsVoid(true);
+    bookmark->mFrecency = 0;
+    bookmark->mHidden = false;
+    bookmark->mVisitCount = 0;
+    bookmark->mLastVisitDate.SetNull();
+    bookmark->mTargetFolderGuid.SetIsVoid(true);
+    bookmark->mTargetFolderItemId = -1;
+    bookmark->mTargetFolderTitle.SetIsVoid(true);
+  }
+
+  bool success = !!notifications.AppendElement(bookmark.forget(), fallible);
+  MOZ_RELEASE_ASSERT(success);
+
+  // If the bookmark has been added to a tag container, notify all
+  // bookmark-folder result nodes which contain a bookmark for the new
+  // bookmark's url.
+  if (grandParentId == tagsRootId) {
+    // Notify a tags change to all bookmarks for this URI.
+    nsTArray<BookmarkData> bookmarks;
+    rv = GetBookmarksForURI(aURI, bookmarks);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsTArray<nsString> tags;
+    rv = GetTags(aURI, tags);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    for (uint32_t i = 0; i < bookmarks.Length(); ++i) {
+      // Check that bookmarks doesn't include the current tag itemId.
+      MOZ_ASSERT(bookmarks[i].id != *aNewBookmarkId);
+      RefPtr<PlacesBookmarkTags> tagsChanged = new PlacesBookmarkTags();
+      tagsChanged->mId = bookmarks[i].id;
+      tagsChanged->mItemType = TYPE_BOOKMARK;
+      tagsChanged->mUrl.Assign(NS_ConvertUTF8toUTF16(utf8spec));
+      tagsChanged->mGuid = bookmarks[i].guid;
+      tagsChanged->mParentGuid = bookmarks[i].parentGuid;
+      tagsChanged->mTags.Assign(tags);
+      tagsChanged->mLastModified = bookmarks[i].lastModified / 1000;
+      tagsChanged->mSource = aSource;
+      tagsChanged->mIsTagging = false;
+      success = !!notifications.AppendElement(tagsChanged.forget(), fallible);
+      MOZ_RELEASE_ASSERT(success);
+    }
+  }
+
+  PlacesObservers::NotifyListeners(notifications);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::RemoveItem(int64_t aItemId, uint16_t aSource) {
+  AUTO_PROFILER_LABEL("nsNavBookmarks::RemoveItem", OTHER);
+
+  BookmarkData bookmark;
+  nsresult rv = FetchItemInfo(aItemId, bookmark);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Check we're not trying to remove a root.
+  NS_ENSURE_ARG(bookmark.parentId > 0 && bookmark.grandParentId > 0);
+
+  mozStorageTransaction transaction(mDB->MainConn(), false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  if (bookmark.type == TYPE_FOLDER) {
+    // Remove all of the folder's children.
+    rv = RemoveFolderChildren(bookmark.id, aSource);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  nsCOMPtr<mozIStorageStatement> stmt =
+      mDB->GetStatement("DELETE FROM moz_bookmarks WHERE id = :item_id");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  rv = stmt->BindInt64ByName("item_id"_ns, bookmark.id);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Fix indices in the parent.
+  if (bookmark.position != DEFAULT_INDEX) {
+    rv = AdjustIndices(bookmark.parentId, bookmark.position + 1, INT32_MAX, -1);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  int64_t syncChangeDelta = DetermineSyncChangeDelta(aSource);
+
+  // Add a tombstone for synced items.
+  if (syncChangeDelta) {
+    rv = InsertTombstone(bookmark);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  bookmark.lastModified = RoundedPRNow();
+  rv = SetItemDateInternal(LAST_MODIFIED, syncChangeDelta, bookmark.parentId,
+                           bookmark.lastModified);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Mark all affected separators as changed
+  rv = AdjustSeparatorsSyncCounter(bookmark.parentId, bookmark.position,
+                                   syncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+  if (bookmark.grandParentId == tagsRootId) {
+    // If we're removing a tag, increment the change counter for all bookmarks
+    // with the URI.
+    rv = AddSyncChangesForBookmarksWithURL(bookmark.url, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIURI> uri;
+  if (bookmark.type == TYPE_BOOKMARK) {
+    // A broken url should not interrupt the removal process.
+    (void)NS_NewURI(getter_AddRefs(uri), bookmark.url);
+    // We cannot assert since some automated tests are checking this path.
+    NS_WARNING_ASSERTION(uri, "Invalid URI in RemoveItem");
+  }
+
+  if (!mCanNotify) {
+    return NS_OK;
+  }
+
+  Sequence<OwningNonNull<PlacesEvent>> notifications;
+  RefPtr<PlacesBookmarkRemoved> bookmarkRef = new PlacesBookmarkRemoved();
+  bookmarkRef->mItemType = bookmark.type;
+  bookmarkRef->mId = bookmark.id;
+  bookmarkRef->mParentId = bookmark.parentId;
+  bookmarkRef->mIndex = bookmark.position;
+  if (bookmark.type == TYPE_BOOKMARK) {
+    bookmarkRef->mUrl.Assign(NS_ConvertUTF8toUTF16(bookmark.url));
+  }
+  bookmarkRef->mTitle.Assign(NS_ConvertUTF8toUTF16(bookmark.title));
+  bookmarkRef->mGuid.Assign(bookmark.guid);
+  bookmarkRef->mParentGuid.Assign(bookmark.parentGuid);
+  bookmarkRef->mSource = aSource;
+  bookmarkRef->mIsTagging =
+      bookmark.parentId == tagsRootId || bookmark.grandParentId == tagsRootId;
+  bookmarkRef->mIsDescendantRemoval = false;
+  bool success = !!notifications.AppendElement(bookmarkRef.forget(), fallible);
+  MOZ_RELEASE_ASSERT(success);
+
+  if (bookmark.type == TYPE_BOOKMARK && bookmark.grandParentId == tagsRootId &&
+      uri) {
+    // If the removed bookmark was child of a tag container, notify a tags
+    // change to all bookmarks for this URI.
+    nsTArray<BookmarkData> bookmarks;
+    rv = GetBookmarksForURI(uri, bookmarks);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsAutoCString utf8spec;
+    uri->GetSpec(utf8spec);
+
+    nsTArray<nsString> tags;
+    rv = GetTags(uri, tags);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    for (uint32_t i = 0; i < bookmarks.Length(); ++i) {
+      RefPtr<PlacesBookmarkTags> tagsChanged = new PlacesBookmarkTags();
+      tagsChanged->mId = bookmarks[i].id;
+      tagsChanged->mItemType = TYPE_BOOKMARK;
+      tagsChanged->mUrl.Assign(NS_ConvertUTF8toUTF16(utf8spec));
+      tagsChanged->mGuid = bookmarks[i].guid;
+      tagsChanged->mParentGuid = bookmarks[i].parentGuid;
+      tagsChanged->mTags.Assign(tags);
+      tagsChanged->mLastModified = bookmarks[i].lastModified / 1000;
+      tagsChanged->mSource = aSource;
+      tagsChanged->mIsTagging = false;
+      success = !!notifications.AppendElement(tagsChanged.forget(), fallible);
+      MOZ_RELEASE_ASSERT(success);
+    }
+  }
+
+  PlacesObservers::NotifyListeners(notifications);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::CreateFolder(int64_t aParent, const nsACString& aTitle,
+                             int32_t aIndex, const nsACString& aGUID,
+                             uint16_t aSource, int64_t* aNewFolderId) {
+  // NOTE: aParent can be null for root creation, so not checked
+  NS_ENSURE_ARG_POINTER(aNewFolderId);
+  NS_ENSURE_ARG_MIN(aIndex, nsINavBookmarksService::DEFAULT_INDEX);
+  if (!aGUID.IsEmpty() && !IsValidGUID(aGUID)) return NS_ERROR_INVALID_ARG;
+
+  // Get the correct index for insertion.  This also ensures the parent exists.
+  int32_t index = aIndex, folderCount;
+  int64_t grandParentId;
+  nsAutoCString folderGuid;
+  nsresult rv =
+      FetchFolderInfo(aParent, &folderCount, folderGuid, &grandParentId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mozStorageTransaction transaction(mDB->MainConn(), false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  if (aIndex == nsINavBookmarksService::DEFAULT_INDEX ||
+      aIndex >= folderCount) {
+    index = folderCount;
+  } else {
+    // Create space for the insertion.
+    rv = AdjustIndices(aParent, index, INT32_MAX, 1);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  *aNewFolderId = -1;
+  PRTime dateAdded = RoundedPRNow();
+  nsAutoCString guid(aGUID);
+  nsCString title;
+  TruncateTitle(aTitle, title);
+
+  rv = InsertBookmarkInDB(-1, FOLDER, aParent, index, title, dateAdded, 0,
+                          folderGuid, grandParentId, nullptr, aSource,
+                          aNewFolderId, guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+
+  if (mCanNotify) {
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    RefPtr<PlacesBookmarkAddition> folder = new PlacesBookmarkAddition();
+    folder->mItemType = TYPE_FOLDER;
+    folder->mId = *aNewFolderId;
+    folder->mParentId = aParent;
+    folder->mIndex = index;
+    folder->mTitle.Assign(NS_ConvertUTF8toUTF16(title));
+    folder->mDateAdded = dateAdded / 1000;
+    folder->mGuid.Assign(guid);
+    folder->mParentGuid.Assign(folderGuid);
+    folder->mSource = aSource;
+    folder->mIsTagging = aParent == tagsRootId;
+    folder->mTags.SetIsVoid(true);
+    folder->mFrecency = 0;
+    folder->mHidden = false;
+    folder->mVisitCount = 0;
+    folder->mLastVisitDate.SetNull();
+    folder->mTargetFolderGuid.SetIsVoid(true);
+    folder->mTargetFolderItemId = -1;
+    folder->mTargetFolderTitle.SetIsVoid(true);
+    bool success = !!events.AppendElement(folder.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+
+    PlacesObservers::NotifyListeners(events);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::GetDescendantChildren(
+    int64_t aFolderId, const nsACString& aFolderGuid, int64_t aGrandParentId,
+    nsTArray<BookmarkData>& aFolderChildrenArray) {
+  // New children will be added from this index on.
+  uint32_t startIndex = aFolderChildrenArray.Length();
+  nsresult rv;
+  {
+    // Collect children informations.
+    // Select all children of a given folder, sorted by position.
+    // This is a LEFT JOIN because not all bookmarks types have a place.
+    // We construct a result where the first columns exactly match
+    // kGetInfoIndex_* order, and additionally contains columns for position,
+    // item_child, and folder_child from moz_bookmarks.
+    nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+        "SELECT h.id, h.url, b.title, h.rev_host, h.visit_count, "
+        "h.last_visit_date, null, b.id, b.dateAdded, b.lastModified, "
+        "b.parent, null, h.frecency, h.hidden, h.guid, null, null, null, "
+        "b.guid, b.position, b.type, b.fk, b.syncStatus "
+        "FROM moz_bookmarks b "
+        "LEFT JOIN moz_places h ON b.fk = h.id "
+        "WHERE b.parent = :parent "
+        "ORDER BY b.position ASC");
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+
+    rv = stmt->BindInt64ByName("parent"_ns, aFolderId);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    bool hasMore;
+    while (NS_SUCCEEDED(stmt->ExecuteStep(&hasMore)) && hasMore) {
+      BookmarkData child;
+      rv = stmt->GetInt64(nsNavHistory::kGetInfoIndex_ItemId, &child.id);
+      NS_ENSURE_SUCCESS(rv, rv);
+      child.parentId = aFolderId;
+      child.grandParentId = aGrandParentId;
+      child.parentGuid = aFolderGuid;
+      rv = stmt->GetInt32(kGetChildrenIndex_Type, &child.type);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->GetInt64(kGetChildrenIndex_PlaceID, &child.placeId);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->GetInt32(kGetChildrenIndex_Position, &child.position);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->GetUTF8String(kGetChildrenIndex_Guid, child.guid);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->GetInt32(kGetChildrenIndex_SyncStatus, &child.syncStatus);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      if (child.type == TYPE_BOOKMARK) {
+        rv = stmt->GetUTF8String(nsNavHistory::kGetInfoIndex_URL, child.url);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      bool isNull;
+      rv = stmt->GetIsNull(nsNavHistory::kGetInfoIndex_Title, &isNull);
+      NS_ENSURE_SUCCESS(rv, rv);
+      if (!isNull) {
+        rv =
+            stmt->GetUTF8String(nsNavHistory::kGetInfoIndex_Title, child.title);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+
+      // Append item to children's array.
+      aFolderChildrenArray.AppendElement(child);
+    }
+  }
+
+  // Recursively call GetDescendantChildren for added folders.
+  // We start at startIndex since previous folders are checked
+  // by previous calls to this method.
+  uint32_t childCount = aFolderChildrenArray.Length();
+  for (uint32_t i = startIndex; i < childCount; ++i) {
+    if (aFolderChildrenArray[i].type == TYPE_FOLDER) {
+      // nsTarray assumes that all children can be memmove()d, thus we can't
+      // just pass aFolderChildrenArray[i].guid to a method that will change
+      // the array itself.  Otherwise, since it's passed by reference, after a
+      // memmove() it could point to garbage and cause intermittent crashes.
+      nsCString guid = aFolderChildrenArray[i].guid;
+      GetDescendantChildren(aFolderChildrenArray[i].id, guid, aFolderId,
+                            aFolderChildrenArray);
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::RemoveFolderChildren(int64_t aFolderId,
+                                              uint16_t aSource) {
+  AUTO_PROFILER_LABEL("nsNavBookmarks::RemoveFolderChilder", OTHER);
+  NS_ENSURE_ARG_MIN(aFolderId, 1);
+
+  BookmarkData folder;
+  nsresult rv = FetchItemInfo(aFolderId, folder);
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_ARG(folder.type == TYPE_FOLDER);
+  NS_ENSURE_ARG(folder.parentId != 0);
+
+  // Fill folder children array recursively.
+  nsTArray<BookmarkData> folderChildrenArray;
+  rv = GetDescendantChildren(folder.id, folder.guid, folder.parentId,
+                             folderChildrenArray);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Build a string of folders whose children will be removed.
+  nsCString foldersToRemove;
+  for (uint32_t i = 0; i < folderChildrenArray.Length(); ++i) {
+    BookmarkData& child = folderChildrenArray[i];
+
+    if (child.type == TYPE_FOLDER) {
+      foldersToRemove.Append(',');
+      foldersToRemove.AppendInt(child.id);
+    }
+  }
+
+  int64_t syncChangeDelta = DetermineSyncChangeDelta(aSource);
+
+  // Delete items from the database now.
+  mozStorageTransaction transaction(mDB->MainConn(), false);
+
+  // XXX Handle the error, bug 1696133.
+  Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+  nsCOMPtr<mozIStorageStatement> deleteStatement =
+      mDB->GetStatement(nsLiteralCString("DELETE FROM moz_bookmarks "
+                                         "WHERE parent IN (:parent") +
+                        foldersToRemove + ")"_ns);
+  NS_ENSURE_STATE(deleteStatement);
+  mozStorageStatementScoper deleteStatementScoper(deleteStatement);
+
+  rv = deleteStatement->BindInt64ByName("parent"_ns, folder.id);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = deleteStatement->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Clean up orphan items annotations.
+  nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
+  if (!conn) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  rv = conn->ExecuteSimpleSQL(
+      nsLiteralCString("DELETE FROM moz_items_annos "
+                       "WHERE id IN ("
+                       "SELECT a.id from moz_items_annos a "
+                       "LEFT JOIN moz_bookmarks b ON a.item_id = b.id "
+                       "WHERE b.id ISNULL)"));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Set the lastModified date.
+  rv = SetItemDateInternal(LAST_MODIFIED, syncChangeDelta, folder.id,
+                           RoundedPRNow());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+
+  if (syncChangeDelta) {
+    nsTArray<TombstoneData> tombstones(folderChildrenArray.Length());
+    PRTime dateRemoved = RoundedPRNow();
+
+    for (uint32_t i = 0; i < folderChildrenArray.Length(); ++i) {
+      BookmarkData& child = folderChildrenArray[i];
+      if (NeedsTombstone(child)) {
+        // Write tombstones for synced children.
+        TombstoneData childTombstone = {child.guid, dateRemoved};
+        tombstones.AppendElement(childTombstone);
+      }
+      bool isUntagging = child.grandParentId == tagsRootId;
+      if (isUntagging) {
+        // Bump the change counter for all tagged bookmarks when removing a tag
+        // folder.
+        rv = AddSyncChangesForBookmarksWithURL(child.url, syncChangeDelta);
+        NS_ENSURE_SUCCESS(rv, rv);
+      }
+    }
+
+    rv = InsertTombstones(tombstones);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  rv = transaction.Commit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  Sequence<OwningNonNull<PlacesEvent>> notifications;
+  // Call observers in reverse order to serve children before their parent.
+  for (int32_t i = folderChildrenArray.Length() - 1; i >= 0; --i) {
+    BookmarkData& child = folderChildrenArray[i];
+
+    nsCOMPtr<nsIURI> uri;
+    if (child.type == TYPE_BOOKMARK) {
+      // A broken url should not interrupt the removal process.
+      (void)NS_NewURI(getter_AddRefs(uri), child.url);
+      // We cannot assert since some automated tests are checking this path.
+      NS_WARNING_ASSERTION(uri, "Invalid URI in RemoveFolderChildren");
+    }
+
+    if (!mCanNotify) {
+      return NS_OK;
+    }
+
+    RefPtr<PlacesBookmarkRemoved> bookmark = new PlacesBookmarkRemoved();
+    bookmark->mItemType = TYPE_BOOKMARK;
+    bookmark->mId = child.id;
+    bookmark->mParentId = child.parentId;
+    bookmark->mIndex = child.position;
+    bookmark->mUrl.Assign(NS_ConvertUTF8toUTF16(child.url));
+    bookmark->mTitle.Assign(NS_ConvertUTF8toUTF16(child.title));
+    bookmark->mGuid.Assign(child.guid);
+    bookmark->mParentGuid.Assign(child.parentGuid);
+    bookmark->mSource = aSource;
+    bookmark->mIsTagging = (child.grandParentId == tagsRootId);
+    bookmark->mIsDescendantRemoval = (child.grandParentId != tagsRootId);
+    bool success = !!notifications.AppendElement(bookmark.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+
+    if (child.type == TYPE_BOOKMARK && child.grandParentId == tagsRootId &&
+        uri) {
+      // If the removed bookmark was a child of a tag container, notify all
+      // bookmark-folder result nodes which contain a bookmark for the removed
+      // bookmark's url.
+      nsTArray<BookmarkData> bookmarks;
+      rv = GetBookmarksForURI(uri, bookmarks);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      nsAutoCString utf8spec;
+      uri->GetSpec(utf8spec);
+
+      nsTArray<nsString> tags;
+      rv = GetTags(uri, tags);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      for (uint32_t i = 0; i < bookmarks.Length(); ++i) {
+        RefPtr<PlacesBookmarkTags> tagsChanged = new PlacesBookmarkTags();
+        tagsChanged->mId = bookmarks[i].id;
+        tagsChanged->mItemType = TYPE_BOOKMARK;
+        tagsChanged->mUrl.Assign(NS_ConvertUTF8toUTF16(utf8spec));
+        tagsChanged->mGuid = bookmarks[i].guid;
+        tagsChanged->mParentGuid = bookmarks[i].parentGuid;
+        tagsChanged->mTags.Assign(tags);
+        tagsChanged->mLastModified = bookmarks[i].lastModified / 1000;
+        tagsChanged->mSource = aSource;
+        tagsChanged->mIsTagging = false;
+        success = !!notifications.AppendElement(tagsChanged.forget(), fallible);
+        MOZ_RELEASE_ASSERT(success);
+      }
+    }
+  }
+
+  if (notifications.Length()) {
+    PlacesObservers::NotifyListeners(notifications);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::FetchItemInfo(int64_t aItemId,
+                                       BookmarkData& _bookmark) {
+  // LEFT JOIN since not all bookmarks have an associated place.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT b.id, h.url, b.title, b.position, b.fk, b.parent, b.type, "
+      "b.dateAdded, b.lastModified, b.guid, t.guid, t.parent, "
+      "b.syncStatus "
+      "FROM moz_bookmarks b "
+      "LEFT JOIN moz_bookmarks t ON t.id = b.parent "
+      "LEFT JOIN moz_places h ON h.id = b.fk "
+      "WHERE b.id = :item_id");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("item_id"_ns, aItemId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!hasResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  _bookmark.id = aItemId;
+  rv = stmt->GetUTF8String(1, _bookmark.url);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isNull;
+  rv = stmt->GetIsNull(2, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = stmt->GetUTF8String(2, _bookmark.title);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  rv = stmt->GetInt32(3, &_bookmark.position);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(4, &_bookmark.placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(5, &_bookmark.parentId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt32(6, &_bookmark.type);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(7, reinterpret_cast<int64_t*>(&_bookmark.dateAdded));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(8, reinterpret_cast<int64_t*>(&_bookmark.lastModified));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetUTF8String(9, _bookmark.guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Getting properties of the root would show no parent.
+  rv = stmt->GetIsNull(10, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = stmt->GetUTF8String(10, _bookmark.parentGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt64(11, &_bookmark.grandParentId);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    _bookmark.grandParentId = -1;
+  }
+  rv = stmt->GetInt32(12, &_bookmark.syncStatus);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::FetchItemInfo(const nsCString& aGUID,
+                                       BookmarkData& _bookmark) {
+  // LEFT JOIN since not all bookmarks have an associated place.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT b.id, h.url, b.title, b.position, b.fk, b.parent, b.type, "
+      "b.dateAdded, b.lastModified, t.guid, t.parent, "
+      "b.syncStatus "
+      "FROM moz_bookmarks b "
+      "LEFT JOIN moz_bookmarks t ON t.id = b.parent "
+      "LEFT JOIN moz_places h ON h.id = b.fk "
+      "WHERE b.guid = :item_guid");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindUTF8StringByName("item_guid"_ns, aGUID);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  _bookmark.guid = aGUID;
+
+  bool hasResult;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!hasResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  rv = stmt->GetInt64(0, &_bookmark.id);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->GetUTF8String(1, _bookmark.url);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isNull;
+  rv = stmt->GetIsNull(2, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = stmt->GetUTF8String(2, _bookmark.title);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  rv = stmt->GetInt32(3, &_bookmark.position);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(4, &_bookmark.placeId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(5, &_bookmark.parentId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt32(6, &_bookmark.type);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(7, reinterpret_cast<int64_t*>(&_bookmark.dateAdded));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->GetInt64(8, reinterpret_cast<int64_t*>(&_bookmark.lastModified));
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Getting properties of the root would show no parent.
+  rv = stmt->GetIsNull(9, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = stmt->GetUTF8String(9, _bookmark.parentGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt64(10, &_bookmark.grandParentId);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    _bookmark.grandParentId = -1;
+  }
+  rv = stmt->GetInt32(11, &_bookmark.syncStatus);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::SetItemDateInternal(enum BookmarkDate aDateType,
+                                             int64_t aSyncChangeDelta,
+                                             int64_t aItemId, PRTime aValue) {
+  aValue = RoundToMilliseconds(aValue);
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET lastModified = :date, "
+      "syncChangeCounter = syncChangeCounter + :delta "
+      "WHERE id = :item_id");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("date"_ns, aValue);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("item_id"_ns, aItemId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("delta"_ns, aSyncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // note, we are not notifying the observers
+  // that the item has changed.
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::SetItemLastModified(int64_t aItemId, PRTime aLastModified,
+                                    uint16_t aSource) {
+  NS_ENSURE_ARG_MIN(aItemId, 1);
+
+  BookmarkData bookmark;
+  nsresult rv = FetchItemInfo(aItemId, bookmark);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+  bool isTagging = bookmark.grandParentId == tagsRootId;
+  int64_t syncChangeDelta = DetermineSyncChangeDelta(aSource);
+
+  // Round here so that we notify with the right value.
+  bookmark.lastModified = RoundToMilliseconds(aLastModified);
+
+  if (isTagging) {
+    // If we're changing a tag, bump the change counter for all tagged
+    // bookmarks. We use a separate code path to avoid a transaction for
+    // non-tags.
+    mozStorageTransaction transaction(mDB->MainConn(), false);
+
+    // XXX Handle the error, bug 1696133.
+    Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+    rv = SetItemDateInternal(LAST_MODIFIED, syncChangeDelta, bookmark.id,
+                             bookmark.lastModified);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = AddSyncChangesForBookmarksWithURL(bookmark.url, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = transaction.Commit();
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    rv = SetItemDateInternal(LAST_MODIFIED, syncChangeDelta, bookmark.id,
+                             bookmark.lastModified);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Note: mDBSetItemDateAdded also sets lastModified to aDateAdded.
+
+  if (mCanNotify) {
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    RefPtr<PlacesBookmarkTime> timeChanged = new PlacesBookmarkTime();
+    timeChanged->mId = bookmark.id;
+    timeChanged->mItemType = bookmark.type;
+    timeChanged->mUrl.Assign(NS_ConvertUTF8toUTF16(bookmark.url));
+    timeChanged->mGuid = bookmark.guid;
+    timeChanged->mParentGuid = bookmark.parentGuid;
+    timeChanged->mDateAdded = bookmark.dateAdded / 1000;
+    timeChanged->mLastModified = bookmark.lastModified / 1000;
+    timeChanged->mSource = aSource;
+    timeChanged->mIsTagging =
+        bookmark.parentId == tagsRootId || bookmark.grandParentId == tagsRootId;
+    bool success = !!events.AppendElement(timeChanged.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+    PlacesObservers::NotifyListeners(events);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::AddSyncChangesForBookmarksWithURL(
+    const nsACString& aURL, int64_t aSyncChangeDelta) {
+  if (!aSyncChangeDelta) {
+    return NS_OK;
+  }
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), aURL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    // Ignore sync changes for invalid URLs.
+    return NS_OK;
+  }
+  return AddSyncChangesForBookmarksWithURI(uri, aSyncChangeDelta);
+}
+
+nsresult nsNavBookmarks::AddSyncChangesForBookmarksWithURI(
+    nsIURI* aURI, int64_t aSyncChangeDelta) {
+  if (NS_WARN_IF(!aURI) || !aSyncChangeDelta) {
+    // Ignore sync changes for invalid URIs.
+    return NS_OK;
+  }
+
+  nsCOMPtr<mozIStorageStatement> statement = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET "
+      "syncChangeCounter = syncChangeCounter + :delta "
+      "WHERE type = :type AND "
+      "fk = (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND "
+      "url = :url)");
+  NS_ENSURE_STATE(statement);
+  mozStorageStatementScoper scoper(statement);
+
+  nsresult rv = statement->BindInt64ByName("delta"_ns, aSyncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = statement->BindInt64ByName("type"_ns,
+                                  nsINavBookmarksService::TYPE_BOOKMARK);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = URIBinder::Bind(statement, "url"_ns, aURI);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return statement->Execute();
+}
+
+nsresult nsNavBookmarks::AddSyncChangesForBookmarksInFolder(
+    int64_t aFolderId, int64_t aSyncChangeDelta) {
+  if (!aSyncChangeDelta) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<mozIStorageStatement> statement = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET "
+      "syncChangeCounter = syncChangeCounter + :delta "
+      "WHERE type = :type AND "
+      "fk = (SELECT fk FROM moz_bookmarks WHERE parent = :parent)");
+  NS_ENSURE_STATE(statement);
+  mozStorageStatementScoper scoper(statement);
+
+  nsresult rv = statement->BindInt64ByName("delta"_ns, aSyncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = statement->BindInt64ByName("type"_ns,
+                                  nsINavBookmarksService::TYPE_BOOKMARK);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = statement->BindInt64ByName("parent"_ns, aFolderId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = statement->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::InsertTombstone(const BookmarkData& aBookmark) {
+  if (!NeedsTombstone(aBookmark)) {
+    return NS_OK;
+  }
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "INSERT INTO moz_bookmarks_deleted (guid, dateRemoved) "
+      "VALUES (:guid, :date_removed)");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindUTF8StringByName("guid"_ns, aBookmark.guid);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt64ByName("date_removed"_ns, RoundedPRNow());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = stmt->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::InsertTombstones(
+    const nsTArray<TombstoneData>& aTombstones) {
+  if (aTombstones.IsEmpty()) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
+  NS_ENSURE_STATE(conn);
+
+  int32_t variableLimit = 0;
+  nsresult rv = conn->GetVariableLimit(&variableLimit);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  size_t maxRowsPerChunk = variableLimit / 2;
+  for (uint32_t startIndex = 0; startIndex < aTombstones.Length();
+       startIndex += maxRowsPerChunk) {
+    size_t rowsPerChunk =
+        std::min(maxRowsPerChunk, aTombstones.Length() - startIndex);
+
+    // Build a query to insert all tombstones in a single statement, chunking to
+    // avoid the SQLite bound parameter limit.
+    nsAutoCString tombstonesToInsert;
+    tombstonesToInsert.AppendLiteral("VALUES (?, ?)");
+    for (uint32_t i = 1; i < rowsPerChunk; ++i) {
+      tombstonesToInsert.AppendLiteral(", (?, ?)");
+    }
+#ifdef DEBUG
+    MOZ_ASSERT(tombstonesToInsert.CountChar('?') == rowsPerChunk * 2,
+               "Expected one binding param per column for each tombstone");
+#endif
+
+    nsCOMPtr<mozIStorageStatement> stmt =
+        mDB->GetStatement(nsLiteralCString("INSERT INTO moz_bookmarks_deleted "
+                                           "(guid, dateRemoved) ") +
+                          tombstonesToInsert);
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+
+    uint32_t paramIndex = 0;
+    for (uint32_t i = 0; i < rowsPerChunk; ++i) {
+      const TombstoneData& tombstone = aTombstones[startIndex + i];
+      rv = stmt->BindUTF8StringByIndex(paramIndex++, tombstone.guid);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = stmt->BindInt64ByIndex(paramIndex++, tombstone.dateRemoved);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::RemoveTombstone(const nsACString& aGUID) {
+  nsCOMPtr<mozIStorageStatement> stmt =
+      mDB->GetStatement("DELETE FROM moz_bookmarks_deleted WHERE guid = :guid");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindUTF8StringByName("guid"_ns, aGUID);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return stmt->Execute();
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::SetItemTitle(int64_t aItemId, const nsACString& aTitle,
+                             uint16_t aSource) {
+  NS_ENSURE_ARG_MIN(aItemId, 1);
+
+  BookmarkData bookmark;
+  nsresult rv = FetchItemInfo(aItemId, bookmark);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+  bool isChangingTagFolder = bookmark.parentId == tagsRootId;
+  int64_t syncChangeDelta = DetermineSyncChangeDelta(aSource);
+
+  nsAutoCString title;
+  TruncateTitle(aTitle, title);
+
+  if (isChangingTagFolder) {
+    // If we're changing the title of a tag folder, bump the change counter
+    // for all tagged bookmarks. We use a separate code path to avoid a
+    // transaction for non-tags.
+    mozStorageTransaction transaction(mDB->MainConn(), false);
+
+    // XXX Handle the error, bug 1696133.
+    Unused << NS_WARN_IF(NS_FAILED(transaction.Start()));
+
+    rv = SetItemTitleInternal(bookmark, title, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = AddSyncChangesForBookmarksInFolder(bookmark.id, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = transaction.Commit();
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    rv = SetItemTitleInternal(bookmark, title, syncChangeDelta);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mCanNotify) {
+    Sequence<OwningNonNull<PlacesEvent>> events;
+    RefPtr<PlacesBookmarkTitle> titleChanged = new PlacesBookmarkTitle();
+    titleChanged->mId = bookmark.id;
+    titleChanged->mItemType = bookmark.type;
+    titleChanged->mUrl.Assign(NS_ConvertUTF8toUTF16(bookmark.url));
+    titleChanged->mGuid = bookmark.guid;
+    titleChanged->mParentGuid = bookmark.parentGuid;
+    titleChanged->mTitle.Assign(NS_ConvertUTF8toUTF16(title));
+    titleChanged->mLastModified = bookmark.lastModified / 1000;
+    titleChanged->mSource = aSource;
+    titleChanged->mIsTagging =
+        bookmark.parentId == tagsRootId || bookmark.grandParentId == tagsRootId;
+    bool success = !!events.AppendElement(titleChanged.forget(), fallible);
+    MOZ_RELEASE_ASSERT(success);
+    PlacesObservers::NotifyListeners(events);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::SetItemTitleInternal(BookmarkData& aBookmark,
+                                              const nsACString& aTitle,
+                                              int64_t aSyncChangeDelta) {
+  nsCOMPtr<mozIStorageStatement> statement = mDB->GetStatement(
+      "UPDATE moz_bookmarks SET "
+      "title = :item_title, lastModified = :date, "
+      "syncChangeCounter = syncChangeCounter + :delta "
+      "WHERE id = :item_id");
+  NS_ENSURE_STATE(statement);
+  mozStorageStatementScoper scoper(statement);
+
+  nsresult rv;
+  if (aTitle.IsEmpty()) {
+    rv = statement->BindNullByName("item_title"_ns);
+  } else {
+    rv = statement->BindUTF8StringByName("item_title"_ns, aTitle);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+  aBookmark.lastModified = RoundToMilliseconds(RoundedPRNow());
+  rv = statement->BindInt64ByName("date"_ns, aBookmark.lastModified);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = statement->BindInt64ByName("item_id"_ns, aBookmark.id);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = statement->BindInt64ByName("delta"_ns, aSyncChangeDelta);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = statement->Execute();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavBookmarks::GetItemTitle(int64_t aItemId, nsACString& _title) {
+  NS_ENSURE_ARG_MIN(aItemId, 1);
+
+  BookmarkData bookmark;
+  nsresult rv = FetchItemInfo(aItemId, bookmark);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  _title = bookmark.title;
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::QueryFolderChildren(
+    int64_t aFolderId, nsNavHistoryQueryOptions* aOptions,
+    nsCOMArray<nsNavHistoryResultNode>* aChildren) {
+  NS_ENSURE_ARG_POINTER(aOptions);
+  NS_ENSURE_ARG_POINTER(aChildren);
+
+  // Select all children of a given folder, sorted by position.
+  // This is a LEFT JOIN because not all bookmarks types have a place.
+  // We construct a result where the first columns exactly match those returned
+  // by mDBGetURLPageInfo, and additionally contains columns for position,
+  // item_child, and folder_child from moz_bookmarks.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      nsNavHistory::GetTagsSqlFragment(
+          nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS,
+          aOptions->ExcludeItems()) +
+      "SELECT "
+      "  h.id, h.url, b.title, h.rev_host, h.visit_count, "
+      "  h.last_visit_date, null, b.id, b.dateAdded, b.lastModified, b.parent, "
+      "  (SELECT tags FROM tagged WHERE place_id = h.id) AS tags, "
+      "  h.frecency, h.hidden, h.guid, null, null, null, "
+      "  b.guid, b.position, b.type, b.fk, t.guid, t.id, t.title "
+      "FROM moz_bookmarks b "
+      "LEFT JOIN moz_places h ON b.fk = h.id "
+      "LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(h.url) "
+      "WHERE b.parent = :parent "
+      "AND (NOT :excludeItems OR "
+      "b.type = :folder OR "
+      "h.url_hash BETWEEN hash('place', 'prefix_lo') "
+      "               AND hash('place', 'prefix_hi')) "
+      "ORDER BY b.position ASC"_ns);
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("parent"_ns, aFolderId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("folder"_ns, TYPE_FOLDER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("excludeItems"_ns, aOptions->ExcludeItems());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<mozIStorageValueArray> row = do_QueryInterface(stmt, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int32_t index = -1;
+  bool hasResult;
+  while (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    rv = ProcessFolderNodeRow(row, aOptions, aChildren, index);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::ProcessFolderNodeRow(
+    mozIStorageValueArray* aRow, nsNavHistoryQueryOptions* aOptions,
+    nsCOMArray<nsNavHistoryResultNode>* aChildren, int32_t& aCurrentIndex) {
+  NS_ENSURE_ARG_POINTER(aRow);
+  NS_ENSURE_ARG_POINTER(aOptions);
+  NS_ENSURE_ARG_POINTER(aChildren);
+
+  // The results will be in order of aCurrentIndex. Even if we don't add a node
+  // because it was excluded, we need to count its index, so do that before
+  // doing anything else.
+  aCurrentIndex++;
+
+  int32_t itemType;
+  nsresult rv = aRow->GetInt32(kGetChildrenIndex_Type, &itemType);
+  NS_ENSURE_SUCCESS(rv, rv);
+  int64_t id;
+  rv = aRow->GetInt64(nsNavHistory::kGetInfoIndex_ItemId, &id);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<nsNavHistoryResultNode> node;
+
+  if (itemType == TYPE_BOOKMARK) {
+    nsNavHistory* history = nsNavHistory::GetHistoryService();
+    NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+    rv = history->RowToResult(aRow, aOptions, getter_AddRefs(node));
+    NS_ENSURE_SUCCESS(rv, rv);
+    uint32_t nodeType;
+    node->GetType(&nodeType);
+    if (nodeType == nsINavHistoryResultNode::RESULT_TYPE_QUERY &&
+        aOptions->ExcludeQueries()) {
+      return NS_OK;
+    }
+  } else if (itemType == TYPE_FOLDER) {
+    nsAutoCString title;
+    bool isNull;
+    rv = aRow->GetIsNull(nsNavHistory::kGetInfoIndex_Title, &isNull);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!isNull) {
+      rv = aRow->GetUTF8String(nsNavHistory::kGetInfoIndex_Title, title);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    nsAutoCString guid;
+    rv = aRow->GetUTF8String(kGetChildrenIndex_Guid, guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Don't use options from the parent to build the new folder node, it will
+    // inherit those later when it's inserted in the result.
+    node = new nsNavHistoryFolderResultNode(id, guid, id, guid, title,
+                                            new nsNavHistoryQueryOptions());
+
+    rv = aRow->GetInt64(nsNavHistory::kGetInfoIndex_ItemDateAdded,
+                        reinterpret_cast<int64_t*>(&node->mDateAdded));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = aRow->GetInt64(nsNavHistory::kGetInfoIndex_ItemLastModified,
+                        reinterpret_cast<int64_t*>(&node->mLastModified));
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    // This is a separator.
+    node = new nsNavHistorySeparatorResultNode();
+
+    node->mItemId = id;
+    rv = aRow->GetUTF8String(kGetChildrenIndex_Guid, node->mBookmarkGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = aRow->GetInt64(nsNavHistory::kGetInfoIndex_ItemDateAdded,
+                        reinterpret_cast<int64_t*>(&node->mDateAdded));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = aRow->GetInt64(nsNavHistory::kGetInfoIndex_ItemLastModified,
+                        reinterpret_cast<int64_t*>(&node->mLastModified));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Store the index of the node within this container.  Note that this is not
+  // moz_bookmarks.position.
+  node->mBookmarkIndex = aCurrentIndex;
+
+  NS_ENSURE_TRUE(aChildren->AppendObject(node), NS_ERROR_OUT_OF_MEMORY);
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::QueryFolderChildrenAsync(
+    nsNavHistoryFolderResultNode* aNode,
+    mozIStoragePendingStatement** _pendingStmt) {
+  NS_ENSURE_ARG_POINTER(aNode);
+  NS_ENSURE_ARG_POINTER(_pendingStmt);
+
+  // Select all children of a given folder, sorted by position.
+  // This is a LEFT JOIN because not all bookmarks types have a place.
+  // We construct a result where the first columns exactly match those returned
+  // by mDBGetURLPageInfo, and additionally contains columns for position,
+  // item_child, and folder_child from moz_bookmarks.
+  nsCOMPtr<mozIStorageAsyncStatement> stmt = mDB->GetAsyncStatement(
+      "SELECT h.id, h.url, b.title, h.rev_host, h.visit_count, "
+      "h.last_visit_date, null, b.id, b.dateAdded, b.lastModified, "
+      "b.parent, null, h.frecency, h.hidden, h.guid, null, null, null, "
+      "b.guid, b.position, b.type, b.fk, t.guid, t.id, t.title "
+      "FROM moz_bookmarks b "
+      "LEFT JOIN moz_places h ON b.fk = h.id "
+      "LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(h.url) "
+      "WHERE b.parent = :parent "
+      "AND (NOT :excludeItems OR "
+      "b.type = :folder OR "
+      "h.url_hash BETWEEN hash('place', 'prefix_lo') AND hash('place', "
+      "'prefix_hi')) "
+      "ORDER BY b.position ASC");
+  NS_ENSURE_STATE(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("parent"_ns, aNode->mTargetFolderItemId);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = stmt->BindInt32ByName("folder"_ns, TYPE_FOLDER);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv =
+      stmt->BindInt32ByName("excludeItems"_ns, aNode->mOptions->ExcludeItems());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<mozIStoragePendingStatement> pendingStmt;
+  rv = stmt->ExecuteAsync(aNode, getter_AddRefs(pendingStmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  NS_IF_ADDREF(*_pendingStmt = pendingStmt);
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::FetchFolderInfo(int64_t aFolderId,
+                                         int32_t* _folderCount,
+                                         nsACString& _guid,
+                                         int64_t* _parentId) {
+  *_folderCount = 0;
+  *_parentId = -1;
+
+  // This query has to always return results, so it can't be written as a join,
+  // though a left join of 2 subqueries would have the same cost.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT count(*), "
+      "(SELECT guid FROM moz_bookmarks WHERE id = :parent), "
+      "(SELECT parent FROM moz_bookmarks WHERE id = :parent) "
+      "FROM moz_bookmarks "
+      "WHERE parent = :parent");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = stmt->BindInt64ByName("parent"_ns, aFolderId);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult;
+  rv = stmt->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(hasResult, NS_ERROR_UNEXPECTED);
+
+  // Ensure that the folder we are looking for exists.
+  // Can't rely only on parent, since the root has parent 0, that doesn't exist.
+  bool isNull;
+  rv = stmt->GetIsNull(2, &isNull);
+  NS_ENSURE_TRUE(NS_SUCCEEDED(rv) && (!isNull || aFolderId == 0),
+                 NS_ERROR_INVALID_ARG);
+
+  rv = stmt->GetInt32(0, _folderCount);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = stmt->GetUTF8String(1, _guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt64(2, _parentId);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavBookmarks::GetBookmarksForURI(
+    nsIURI* aURI, nsTArray<BookmarkData>& aBookmarks) {
+  NS_ENSURE_ARG(aURI);
+
+  // Double ordering covers possible lastModified ties, that could happen when
+  // importing, syncing or due to extensions.
+  // Note: not using a JOIN is cheaper in this case.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "/* do not warn (bug 1175249) */ "
+      "SELECT b.id, b.guid, b.parent, b.lastModified, t.guid, t.parent, "
+      "b.syncStatus "
+      "FROM moz_bookmarks b "
+      "JOIN moz_bookmarks t on t.id = b.parent "
+      "WHERE b.fk = (SELECT id FROM moz_places WHERE url_hash = "
+      "hash(:page_url) AND url = :page_url) "
+      "ORDER BY b.lastModified DESC, b.id DESC ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = URIBinder::Bind(stmt, "page_url"_ns, aURI);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int64_t tagsRootId = mDB->GetTagsFolderId();
+
+  bool more;
+  nsAutoString tags;
+  while (NS_SUCCEEDED((rv = stmt->ExecuteStep(&more))) && more) {
+    // Skip tags.
+    int64_t grandParentId;
+    nsresult rv = stmt->GetInt64(5, &grandParentId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (grandParentId == tagsRootId) {
+      continue;
+    }
+
+    BookmarkData bookmark;
+    bookmark.grandParentId = grandParentId;
+    rv = stmt->GetInt64(0, &bookmark.id);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetUTF8String(1, bookmark.guid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt64(2, &bookmark.parentId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt64(3, reinterpret_cast<int64_t*>(&bookmark.lastModified));
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetUTF8String(4, bookmark.parentGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetInt32(6, &bookmark.syncStatus);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    aBookmarks.AppendElement(bookmark);
+  }
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+nsNavBookmarks::Observe(nsISupports* aSubject, const char* aTopic,
+                        const char16_t* aData) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+
+  if (strcmp(aTopic, TOPIC_PLACES_CONNECTION_CLOSED) == 0) {
+    // Don't even try to notify observers from this point on, the category
+    // cache would init services that could try to use our APIs.
+    mCanNotify = false;
+  }
+
+  return NS_OK;
+}
diff --git a/toolkit/components/places/nsNavBookmarks.h b/toolkit/components/places/nsNavBookmarks.h
new file mode 100644
index 0000000000..ab3fd1b0af
--- /dev/null
+++ b/toolkit/components/places/nsNavBookmarks.h
@@ -0,0 +1,308 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsNavBookmarks_h_
+#define nsNavBookmarks_h_
+
+#include "nsINavBookmarksService.h"
+#include "nsNavHistory.h"
+#include "nsToolkitCompsCID.h"
+#include "nsCategoryCache.h"
+#include "nsTHashtable.h"
+#include "mozilla/Attributes.h"
+#include "prtime.h"
+
+class nsNavBookmarks;
+
+namespace mozilla {
+namespace places {
+
+enum BookmarkStatementId {
+  DB_FIND_REDIRECTED_BOOKMARK = 0,
+  DB_GET_BOOKMARKS_FOR_URI
+};
+
+struct BookmarkData {
+  int64_t id = -1;
+  nsCString url;
+  nsCString title;
+  int32_t position = -1;
+  int64_t placeId = -1;
+  int64_t parentId = -1;
+  int64_t grandParentId = -1;
+  int32_t type = 0;
+  int32_t syncStatus = nsINavBookmarksService::SYNC_STATUS_UNKNOWN;
+  nsCString serviceCID;
+  PRTime dateAdded = 0;
+  PRTime lastModified = 0;
+  nsCString guid;
+  nsCString parentGuid;
+};
+
+struct ItemVisitData {
+  BookmarkData bookmark;
+  int64_t visitId;
+  uint32_t transitionType;
+  PRTime time;
+};
+
+struct TombstoneData {
+  nsCString guid;
+  PRTime dateRemoved;
+};
+
+typedef void (nsNavBookmarks::*ItemVisitMethod)(const ItemVisitData&);
+
+enum BookmarkDate { LAST_MODIFIED };
+
+}  // namespace places
+}  // namespace mozilla
+
+class nsNavBookmarks final : public nsINavBookmarksService,
+                             public nsIObserver,
+                             public nsSupportsWeakReference {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSINAVBOOKMARKSSERVICE
+  NS_DECL_NSIOBSERVER
+
+  nsNavBookmarks();
+
+  /**
+   * Obtains the service's object.
+   */
+  static already_AddRefed<nsNavBookmarks> GetSingleton();
+
+  /**
+   * Initializes the service's object.  This should only be called once.
+   */
+  nsresult Init();
+
+  static nsNavBookmarks* GetBookmarksService() {
+    if (!gBookmarksService) {
+      nsCOMPtr<nsINavBookmarksService> serv =
+          do_GetService(NS_NAVBOOKMARKSSERVICE_CONTRACTID);
+      NS_ENSURE_TRUE(serv, nullptr);
+      NS_ASSERTION(gBookmarksService,
+                   "Should have static instance pointer now");
+    }
+    return gBookmarksService;
+  }
+
+  typedef mozilla::places::BookmarkData BookmarkData;
+  typedef mozilla::places::ItemVisitData ItemVisitData;
+  typedef mozilla::places::BookmarkStatementId BookmarkStatementId;
+
+  nsresult OnVisit(nsIURI* aURI, int64_t aVisitId, PRTime aTime,
+                   int64_t aSessionId, int64_t aReferringId,
+                   uint32_t aTransitionType, const nsACString& aGUID,
+                   bool aHidden, uint32_t aVisitCount, uint32_t aTyped,
+                   const nsAString& aLastKnownTitle);
+
+  // Find all the children of a folder, using the given query and options.
+  // For each child, a ResultNode is created and added to |children|.
+  // The results are ordered by folder position.
+  nsresult QueryFolderChildren(int64_t aFolderId,
+                               nsNavHistoryQueryOptions* aOptions,
+                               nsCOMArray<nsNavHistoryResultNode>* children);
+
+  /**
+   * Turns aRow into a node and appends it to aChildren if it is appropriate to
+   * do so.
+   *
+   * @param aRow
+   *        A Storage statement (in the case of synchronous execution) or row of
+   *        a result set (in the case of asynchronous execution).
+   * @param aOptions
+   *        The options of the parent folder node. These are the options used
+   *        to fill the parent node.
+   * @param aChildren
+   *        The children of the parent folder node.
+   * @param aCurrentIndex
+   *        The index of aRow within the results.  When called on the first row,
+   *        this should be set to -1.
+   */
+  nsresult ProcessFolderNodeRow(mozIStorageValueArray* aRow,
+                                nsNavHistoryQueryOptions* aOptions,
+                                nsCOMArray<nsNavHistoryResultNode>* aChildren,
+                                int32_t& aCurrentIndex);
+
+  /**
+   * The async version of QueryFolderChildren.
+   *
+   * @param aNode
+   *        The folder node that will receive the children.
+   * @param _pendingStmt
+   *        The Storage pending statement that will be used to control async
+   *        execution.
+   */
+  nsresult QueryFolderChildrenAsync(nsNavHistoryFolderResultNode* aNode,
+                                    mozIStoragePendingStatement** _pendingStmt);
+
+  /**
+   * Fetches information about the specified id from the database.
+   *
+   * @param aItemId
+   *        Id of the item to fetch information for.
+   * @param aBookmark
+   *        BookmarkData to store the information.
+   */
+  nsresult FetchItemInfo(int64_t aItemId, BookmarkData& _bookmark);
+
+  /**
+   * Fetches information about the specified GUID from the database.
+   *
+   * @param aGUID
+   *        GUID of the item to fetch information for.
+   * @param aBookmark
+   *        BookmarkData to store the information.
+   */
+  nsresult FetchItemInfo(const nsCString& aGUID, BookmarkData& _bookmark);
+
+  /**
+   * Notifies that a bookmark has been visited.
+   *
+   * @param aItemId
+   *        The visited item id.
+   * @param aData
+   *        Details about the new visit.
+   */
+  void NotifyItemVisited(const ItemVisitData& aData);
+
+  static const int32_t kGetChildrenIndex_Guid;
+  static const int32_t kGetChildrenIndex_Position;
+  static const int32_t kGetChildrenIndex_Type;
+  static const int32_t kGetChildrenIndex_PlaceID;
+  static const int32_t kGetChildrenIndex_SyncStatus;
+
+  static mozilla::Atomic<int64_t> sLastInsertedItemId;
+  static void StoreLastInsertedId(const nsACString& aTable,
+                                  const int64_t aLastInsertedId);
+
+  static mozilla::Atomic<int64_t> sTotalSyncChanges;
+  static void NoteSyncChange();
+
+ private:
+  static nsNavBookmarks* gBookmarksService;
+
+  ~nsNavBookmarks();
+
+  nsresult AdjustIndices(int64_t aFolder, int32_t aStartIndex,
+                         int32_t aEndIndex, int32_t aDelta);
+
+  nsresult AdjustSeparatorsSyncCounter(int64_t aFolderId, int32_t aStartIndex,
+                                       int64_t aSyncChangeDelta);
+
+  /**
+   * Fetches properties of a folder.
+   *
+   * @param aFolderId
+   *        Folder to count children for.
+   * @param _folderCount
+   *        Number of children in the folder.
+   * @param _guid
+   *        Unique id of the folder.
+   * @param _parentId
+   *        Id of the parent of the folder.
+   *
+   * @throws If folder does not exist.
+   */
+  nsresult FetchFolderInfo(int64_t aFolderId, int32_t* _folderCount,
+                           nsACString& _guid, int64_t* _parentId);
+
+  nsresult AddSyncChangesForBookmarksWithURL(const nsACString& aURL,
+                                             int64_t aSyncChangeDelta);
+
+  // Bumps the change counter for all bookmarks with |aURI|. This is used to
+  // update tagged bookmarks when adding or changing a tag entry.
+  nsresult AddSyncChangesForBookmarksWithURI(nsIURI* aURI,
+                                             int64_t aSyncChangeDelta);
+
+  // Bumps the change counter for all bookmarked URLs within |aFolderId|. This
+  // is used to update tagged bookmarks when changing or removing a tag folder.
+  nsresult AddSyncChangesForBookmarksInFolder(int64_t aFolderId,
+                                              int64_t aSyncChangeDelta);
+
+  // Inserts a tombstone for a removed synced item.
+  nsresult InsertTombstone(const BookmarkData& aBookmark);
+
+  // Inserts tombstones for removed synced items.
+  nsresult InsertTombstones(
+      const nsTArray<mozilla::places::TombstoneData>& aTombstones);
+
+  // Removes a stale synced bookmark tombstone.
+  nsresult RemoveTombstone(const nsACString& aGUID);
+
+  nsresult SetItemTitleInternal(BookmarkData& aBookmark,
+                                const nsACString& aTitle,
+                                int64_t aSyncChangeDelta);
+
+  /**
+   * This is an handle to the Places database.
+   */
+  RefPtr<mozilla::places::Database> mDB;
+
+  nsresult SetItemDateInternal(enum mozilla::places::BookmarkDate aDateType,
+                               int64_t aSyncChangeDelta, int64_t aItemId,
+                               PRTime aValue);
+
+  MOZ_CAN_RUN_SCRIPT
+  nsresult RemoveFolderChildren(int64_t aFolderId, uint16_t aSource);
+
+  // Recursive method to build an array of folder's children
+  nsresult GetDescendantChildren(int64_t aFolderId,
+                                 const nsACString& aFolderGuid,
+                                 int64_t aGrandParentId,
+                                 nsTArray<BookmarkData>& aFolderChildrenArray);
+
+  enum ItemType {
+    BOOKMARK = TYPE_BOOKMARK,
+    FOLDER = TYPE_FOLDER,
+    SEPARATOR = TYPE_SEPARATOR,
+  };
+
+  /**
+   * Helper to insert a bookmark in the database.
+   *
+   *  @param aItemId
+   *         The itemId to insert, pass -1 to generate a new one.
+   *  @param aPlaceId
+   *         The placeId to which this bookmark refers to, pass nullptr for
+   *         items that don't refer to an URI (eg. folders, separators, ...).
+   *  @param aItemType
+   *         The type of the new bookmark, see TYPE_* constants.
+   *  @param aParentId
+   *         The itemId of the parent folder.
+   *  @param aIndex
+   *         The position inside the parent folder.
+   *  @param aTitle
+   *         The title for the new bookmark.
+   *         Pass a void string to set a NULL title.
+   *  @param aDateAdded
+   *         The date for the insertion.
+   *  @param [optional] aLastModified
+   *         The last modified date for the insertion.
+   *         It defaults to aDateAdded.
+   *
+   *  @return The new item id that has been inserted.
+   *
+   *  @note This will also update last modified date of the parent folder.
+   */
+  nsresult InsertBookmarkInDB(int64_t aPlaceId, enum ItemType aItemType,
+                              int64_t aParentId, int32_t aIndex,
+                              const nsACString& aTitle, PRTime aDateAdded,
+                              PRTime aLastModified,
+                              const nsACString& aParentGuid,
+                              int64_t aGrandParentId, nsIURI* aURI,
+                              uint16_t aSource, int64_t* _itemId,
+                              nsACString& _guid);
+
+  nsresult GetBookmarksForURI(nsIURI* aURI, nsTArray<BookmarkData>& _bookmarks);
+
+  // Used to enable and disable the observer notifications.
+  bool mCanNotify;
+};
+
+#endif  // nsNavBookmarks_h_
diff --git a/toolkit/components/places/nsNavHistory.cpp b/toolkit/components/places/nsNavHistory.cpp
new file mode 100644
index 0000000000..80df05913a
--- /dev/null
+++ b/toolkit/components/places/nsNavHistory.cpp
@@ -0,0 +1,2826 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+
+#include "mozilla/Components.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/intl/LocaleService.h"
+
+#include "nsNavHistory.h"
+
+#include "mozIPlacesAutoComplete.h"
+#include "nsNavBookmarks.h"
+#include "nsFaviconService.h"
+#include "nsPlacesMacros.h"
+#include "nsPlacesTriggers.h"
+#include "mozilla/intl/AppDateTimeFormat.h"
+#include "History.h"
+#include "Helpers.h"
+#include "NotifyRankingChanged.h"
+
+#include "mozIStorageValueArray.h"
+#include "nsTArray.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsPromiseFlatString.h"
+#include "nsString.h"
+#include "nsUnicharUtils.h"
+#include "prsystem.h"
+#include "prtime.h"
+#include "nsEscape.h"
+#include "nsIEffectiveTLDService.h"
+#include "nsIClassInfoImpl.h"
+#include "nsIIDNService.h"
+#include "nsQueryObject.h"
+#include "nsThreadUtils.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsMathUtils.h"
+#include "nsReadableUtils.h"
+#include "mozilla/storage.h"
+#include "mozilla/Preferences.h"
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::places;
+
+// The maximum number of things that we will store in the recent events list
+// before calling ExpireNonrecentEvents. This number should be big enough so it
+// is very difficult to get that many unconsumed events (for example, typed but
+// never visited) in the RECENT_EVENT_THRESHOLD. Otherwise, we'll start
+// checking each one for every page visit, which will be somewhat slower.
+#define RECENT_EVENT_QUEUE_MAX_LENGTH 128
+
+// preference ID strings
+#define PREF_HISTORY_ENABLED "places.history.enabled"
+#define PREF_MATCH_DIACRITICS "places.search.matchDiacritics"
+
+#define PREF_FREC_NUM_VISITS "places.frecency.numVisits"
+#define PREF_FREC_NUM_VISITS_DEF 10
+#define PREF_FREC_FIRST_BUCKET_CUTOFF "places.frecency.firstBucketCutoff"
+#define PREF_FREC_FIRST_BUCKET_CUTOFF_DEF 4
+#define PREF_FREC_SECOND_BUCKET_CUTOFF "places.frecency.secondBucketCutoff"
+#define PREF_FREC_SECOND_BUCKET_CUTOFF_DEF 14
+#define PREF_FREC_THIRD_BUCKET_CUTOFF "places.frecency.thirdBucketCutoff"
+#define PREF_FREC_THIRD_BUCKET_CUTOFF_DEF 31
+#define PREF_FREC_FOURTH_BUCKET_CUTOFF "places.frecency.fourthBucketCutoff"
+#define PREF_FREC_FOURTH_BUCKET_CUTOFF_DEF 90
+#define PREF_FREC_FIRST_BUCKET_WEIGHT "places.frecency.firstBucketWeight"
+#define PREF_FREC_FIRST_BUCKET_WEIGHT_DEF 100
+#define PREF_FREC_SECOND_BUCKET_WEIGHT "places.frecency.secondBucketWeight"
+#define PREF_FREC_SECOND_BUCKET_WEIGHT_DEF 70
+#define PREF_FREC_THIRD_BUCKET_WEIGHT "places.frecency.thirdBucketWeight"
+#define PREF_FREC_THIRD_BUCKET_WEIGHT_DEF 50
+#define PREF_FREC_FOURTH_BUCKET_WEIGHT "places.frecency.fourthBucketWeight"
+#define PREF_FREC_FOURTH_BUCKET_WEIGHT_DEF 30
+#define PREF_FREC_DEFAULT_BUCKET_WEIGHT "places.frecency.defaultBucketWeight"
+#define PREF_FREC_DEFAULT_BUCKET_WEIGHT_DEF 10
+#define PREF_FREC_EMBED_VISIT_BONUS "places.frecency.embedVisitBonus"
+#define PREF_FREC_EMBED_VISIT_BONUS_DEF 0
+#define PREF_FREC_FRAMED_LINK_VISIT_BONUS "places.frecency.framedLinkVisitBonus"
+#define PREF_FREC_FRAMED_LINK_VISIT_BONUS_DEF 0
+#define PREF_FREC_LINK_VISIT_BONUS "places.frecency.linkVisitBonus"
+#define PREF_FREC_LINK_VISIT_BONUS_DEF 100
+#define PREF_FREC_TYPED_VISIT_BONUS "places.frecency.typedVisitBonus"
+#define PREF_FREC_TYPED_VISIT_BONUS_DEF 2000
+#define PREF_FREC_BOOKMARK_VISIT_BONUS "places.frecency.bookmarkVisitBonus"
+#define PREF_FREC_BOOKMARK_VISIT_BONUS_DEF 75
+#define PREF_FREC_DOWNLOAD_VISIT_BONUS "places.frecency.downloadVisitBonus"
+#define PREF_FREC_DOWNLOAD_VISIT_BONUS_DEF 0
+#define PREF_FREC_PERM_REDIRECT_VISIT_BONUS \
+  "places.frecency.permRedirectVisitBonus"
+#define PREF_FREC_PERM_REDIRECT_VISIT_BONUS_DEF 0
+#define PREF_FREC_TEMP_REDIRECT_VISIT_BONUS \
+  "places.frecency.tempRedirectVisitBonus"
+#define PREF_FREC_TEMP_REDIRECT_VISIT_BONUS_DEF 0
+#define PREF_FREC_REDIR_SOURCE_VISIT_BONUS \
+  "places.frecency.redirectSourceVisitBonus"
+#define PREF_FREC_REDIR_SOURCE_VISIT_BONUS_DEF 25
+#define PREF_FREC_DEFAULT_VISIT_BONUS "places.frecency.defaultVisitBonus"
+#define PREF_FREC_DEFAULT_VISIT_BONUS_DEF 0
+#define PREF_FREC_UNVISITED_BOOKMARK_BONUS \
+  "places.frecency.unvisitedBookmarkBonus"
+#define PREF_FREC_UNVISITED_BOOKMARK_BONUS_DEF 140
+#define PREF_FREC_UNVISITED_TYPED_BONUS "places.frecency.unvisitedTypedBonus"
+#define PREF_FREC_UNVISITED_TYPED_BONUS_DEF 200
+#define PREF_FREC_RELOAD_VISIT_BONUS "places.frecency.reloadVisitBonus"
+#define PREF_FREC_RELOAD_VISIT_BONUS_DEF 0
+
+// In order to avoid calling PR_now() too often we use a cached "now" value
+// for repeating stuff.  These are milliseconds between "now" cache refreshes.
+#define RENEW_CACHED_NOW_TIMEOUT ((int32_t)3 * PR_MSEC_PER_SEC)
+
+// These macros are used when splitting history by date.
+// These are the day containers and catch-all final container.
+#define HISTORY_ADDITIONAL_DATE_CONT_NUM 3
+// We use a guess of the number of months considering all of them 30 days
+// long, but we split only the last 6 months.
+#define HISTORY_DATE_CONT_NUM(_daysFromOldestVisit) \
+  (HISTORY_ADDITIONAL_DATE_CONT_NUM +               \
+   std::min(6, (int32_t)ceilf((float)_daysFromOldestVisit / 30)))
+// Max number of containers, used to initialize the params hash.
+#define HISTORY_DATE_CONT_LENGTH 8
+
+// Initial length of the recent events cache.
+#define RECENT_EVENTS_INITIAL_CACHE_LENGTH 64
+
+// Observed topics.
+#define TOPIC_IDLE_DAILY "idle-daily"
+#define TOPIC_PREF_CHANGED "nsPref:changed"
+#define TOPIC_PROFILE_TEARDOWN "profile-change-teardown"
+#define TOPIC_PROFILE_CHANGE "profile-before-change"
+#define TOPIC_APP_LOCALES_CHANGED "intl:app-locales-changed"
+
+static const char* kObservedPrefs[] = {PREF_HISTORY_ENABLED,
+                                       PREF_MATCH_DIACRITICS,
+                                       PREF_FREC_NUM_VISITS,
+                                       PREF_FREC_FIRST_BUCKET_CUTOFF,
+                                       PREF_FREC_SECOND_BUCKET_CUTOFF,
+                                       PREF_FREC_THIRD_BUCKET_CUTOFF,
+                                       PREF_FREC_FOURTH_BUCKET_CUTOFF,
+                                       PREF_FREC_FIRST_BUCKET_WEIGHT,
+                                       PREF_FREC_SECOND_BUCKET_WEIGHT,
+                                       PREF_FREC_THIRD_BUCKET_WEIGHT,
+                                       PREF_FREC_FOURTH_BUCKET_WEIGHT,
+                                       PREF_FREC_DEFAULT_BUCKET_WEIGHT,
+                                       PREF_FREC_EMBED_VISIT_BONUS,
+                                       PREF_FREC_FRAMED_LINK_VISIT_BONUS,
+                                       PREF_FREC_LINK_VISIT_BONUS,
+                                       PREF_FREC_TYPED_VISIT_BONUS,
+                                       PREF_FREC_BOOKMARK_VISIT_BONUS,
+                                       PREF_FREC_DOWNLOAD_VISIT_BONUS,
+                                       PREF_FREC_PERM_REDIRECT_VISIT_BONUS,
+                                       PREF_FREC_TEMP_REDIRECT_VISIT_BONUS,
+                                       PREF_FREC_REDIR_SOURCE_VISIT_BONUS,
+                                       PREF_FREC_DEFAULT_VISIT_BONUS,
+                                       PREF_FREC_UNVISITED_BOOKMARK_BONUS,
+                                       PREF_FREC_UNVISITED_TYPED_BONUS,
+                                       nullptr};
+
+NS_IMPL_ADDREF(nsNavHistory)
+NS_IMPL_RELEASE(nsNavHistory)
+
+NS_IMPL_CLASSINFO(nsNavHistory, nullptr, nsIClassInfo::SINGLETON,
+                  NS_NAVHISTORYSERVICE_CID)
+NS_INTERFACE_MAP_BEGIN(nsNavHistory)
+  NS_INTERFACE_MAP_ENTRY(nsINavHistoryService)
+  NS_INTERFACE_MAP_ENTRY(nsIObserver)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY(mozIStorageVacuumParticipant)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsINavHistoryService)
+  NS_IMPL_QUERY_CLASSINFO(nsNavHistory)
+NS_INTERFACE_MAP_END
+
+// We don't care about flattening everything
+NS_IMPL_CI_INTERFACE_GETTER(nsNavHistory, nsINavHistoryService)
+
+namespace {
+
+static Maybe<nsCString> GetSimpleBookmarksQueryParent(
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions);
+static void ParseSearchTermsFromQuery(const RefPtr<nsNavHistoryQuery>& aQuery,
+                                      nsTArray<nsString>* aTerms);
+
+nsresult FetchInfo(const RefPtr<mozilla::places::Database>& aDB,
+                   const nsCString& aGUID, int32_t& aType, int64_t& aId,
+                   nsCString& aTitle, PRTime& aDateAdded,
+                   PRTime& aLastModified) {
+  nsCOMPtr<mozIStorageStatement> statement = aDB->GetStatement(
+      "SELECT type, id, title, dateAdded, lastModified FROM moz_bookmarks "
+      "WHERE guid = :guid");
+  NS_ENSURE_STATE(statement);
+  mozStorageStatementScoper scoper(statement);
+  nsresult rv = statement->BindUTF8StringByName("guid"_ns, aGUID);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasResult;
+  rv = statement->ExecuteStep(&hasResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!hasResult) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  aType = statement->AsInt32(0);
+  aId = statement->AsInt64(1);
+
+  bool isNull;
+  rv = statement->GetIsNull(2, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (isNull) {
+    aTitle.SetIsVoid(true);
+  } else {
+    rv = statement->GetUTF8String(2, aTitle);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  aDateAdded = statement->AsInt64(3);
+  NS_ENSURE_SUCCESS(rv, rv);
+  aLastModified = statement->AsInt64(4);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+}  // namespace
+
+// Queries rows indexes to bind or get values, if adding a new one, be sure to
+// update nsNavBookmarks statements and its kGetChildrenIndex_* constants
+const int32_t nsNavHistory::kGetInfoIndex_PageID = 0;
+const int32_t nsNavHistory::kGetInfoIndex_URL = 1;
+const int32_t nsNavHistory::kGetInfoIndex_Title = 2;
+const int32_t nsNavHistory::kGetInfoIndex_RevHost = 3;
+const int32_t nsNavHistory::kGetInfoIndex_VisitCount = 4;
+const int32_t nsNavHistory::kGetInfoIndex_VisitDate = 5;
+const int32_t nsNavHistory::kGetInfoIndex_FaviconURL = 6;
+const int32_t nsNavHistory::kGetInfoIndex_ItemId = 7;
+const int32_t nsNavHistory::kGetInfoIndex_ItemDateAdded = 8;
+const int32_t nsNavHistory::kGetInfoIndex_ItemLastModified = 9;
+const int32_t nsNavHistory::kGetInfoIndex_ItemParentId = 10;
+const int32_t nsNavHistory::kGetInfoIndex_ItemTags = 11;
+const int32_t nsNavHistory::kGetInfoIndex_Frecency = 12;
+const int32_t nsNavHistory::kGetInfoIndex_Hidden = 13;
+const int32_t nsNavHistory::kGetInfoIndex_Guid = 14;
+const int32_t nsNavHistory::kGetInfoIndex_VisitId = 15;
+const int32_t nsNavHistory::kGetInfoIndex_FromVisitId = 16;
+const int32_t nsNavHistory::kGetInfoIndex_VisitType = 17;
+// These columns are followed by corresponding constants in nsNavBookmarks.cpp,
+// which must be kept in sync:
+// nsNavBookmarks::kGetChildrenIndex_Guid = 18;
+// nsNavBookmarks::kGetChildrenIndex_Position = 19;
+// nsNavBookmarks::kGetChildrenIndex_Type = 20;
+// nsNavBookmarks::kGetChildrenIndex_PlaceID = 21;
+const int32_t nsNavHistory::kGetTargetFolder_Guid = 22;
+const int32_t nsNavHistory::kGetTargetFolder_ItemId = 23;
+const int32_t nsNavHistory::kGetTargetFolder_Title = 24;
+
+PLACES_FACTORY_SINGLETON_IMPLEMENTATION(nsNavHistory, gHistoryService)
+
+nsNavHistory::nsNavHistory()
+    : mCachedNow(0),
+      mRecentTyped(RECENT_EVENTS_INITIAL_CACHE_LENGTH),
+      mRecentLink(RECENT_EVENTS_INITIAL_CACHE_LENGTH),
+      mRecentBookmark(RECENT_EVENTS_INITIAL_CACHE_LENGTH),
+      mHistoryEnabled(true),
+      mMatchDiacritics(false),
+      mNumVisitsForFrecency(10),
+      mTagsFolder(-1),
+      mLastCachedStartOfDay(INT64_MAX),
+      mLastCachedEndOfDay(0) {
+  NS_ASSERTION(!gHistoryService,
+               "Attempting to create two instances of the service!");
+  gHistoryService = this;
+}
+
+nsNavHistory::~nsNavHistory() {
+  MOZ_ASSERT(NS_IsMainThread(), "Must be called on the main thread");
+
+  // remove the static reference to the service. Check to make sure its us
+  // in case somebody creates an extra instance of the service.
+  NS_ASSERTION(gHistoryService == this,
+               "Deleting a non-singleton instance of the service");
+
+  if (gHistoryService == this) gHistoryService = nullptr;
+}
+
+nsresult nsNavHistory::Init() {
+  LoadPrefs();
+
+  mDB = Database::GetDatabase();
+  NS_ENSURE_STATE(mDB);
+
+  /*****************************************************************************
+   *** IMPORTANT NOTICE!
+   ***
+   *** Nothing after these add observer calls should return anything but NS_OK.
+   *** If a failure code is returned, this nsNavHistory object will be held onto
+   *** by the observer service and the preference service.
+   ****************************************************************************/
+
+  // Observe preferences changes.
+  Preferences::AddWeakObservers(this, kObservedPrefs);
+
+  nsCOMPtr<nsIObserverService> obsSvc = services::GetObserverService();
+  if (obsSvc) {
+    (void)obsSvc->AddObserver(this, TOPIC_PLACES_CONNECTION_CLOSED, true);
+    (void)obsSvc->AddObserver(this, TOPIC_IDLE_DAILY, true);
+    (void)obsSvc->AddObserver(this, TOPIC_APP_LOCALES_CHANGED, true);
+  }
+
+  // Don't add code that can fail here! Do it up above, before we add our
+  // observers.
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetDatabaseStatus(uint16_t* aDatabaseStatus) {
+  NS_ENSURE_ARG_POINTER(aDatabaseStatus);
+  *aDatabaseStatus = mDB->GetDatabaseStatus();
+  return NS_OK;
+}
+
+uint32_t nsNavHistory::GetRecentFlags(nsIURI* aURI) {
+  uint32_t result = 0;
+  nsAutoCString spec;
+  nsresult rv = aURI->GetSpec(spec);
+  NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Unable to get aURI's spec");
+
+  if (NS_SUCCEEDED(rv)) {
+    if (CheckIsRecentEvent(&mRecentTyped, spec)) result |= RECENT_TYPED;
+    if (CheckIsRecentEvent(&mRecentLink, spec)) result |= RECENT_ACTIVATED;
+    if (CheckIsRecentEvent(&mRecentBookmark, spec)) result |= RECENT_BOOKMARKED;
+  }
+
+  return result;
+}
+
+nsresult nsNavHistory::GetIdForPage(nsIURI* aURI, int64_t* _pageId,
+                                    nsCString& _GUID) {
+  *_pageId = 0;
+
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT id, url, title, rev_host, visit_count, guid "
+      "FROM moz_places "
+      "WHERE url_hash = hash(:page_url) AND url = :page_url ");
+  NS_ENSURE_STATE(stmt);
+  mozStorageStatementScoper scoper(stmt);
+
+  nsresult rv = URIBinder::Bind(stmt, "page_url"_ns, aURI);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasEntry = false;
+  rv = stmt->ExecuteStep(&hasEntry);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (hasEntry) {
+    rv = stmt->GetInt64(0, _pageId);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->GetUTF8String(5, _GUID);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistory::GetOrCreateIdForPage(nsIURI* aURI, int64_t* _pageId,
+                                            nsCString& _GUID) {
+  nsresult rv = GetIdForPage(aURI, _pageId, _GUID);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (*_pageId != 0) {
+    return NS_OK;
+  }
+
+  {
+    // Create a new hidden, untyped and unvisited entry.
+    nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+        "INSERT INTO moz_places (url, url_hash, rev_host, hidden, frecency, "
+        "guid) "
+        "VALUES (:page_url, hash(:page_url), :rev_host, :hidden, :frecency, "
+        ":guid) ");
+    NS_ENSURE_STATE(stmt);
+    mozStorageStatementScoper scoper(stmt);
+
+    rv = URIBinder::Bind(stmt, "page_url"_ns, aURI);
+    NS_ENSURE_SUCCESS(rv, rv);
+    // host (reversed with trailing period)
+    nsAutoString revHost;
+    rv = GetReversedHostname(aURI, revHost);
+    // Not all URI types have hostnames, so this is optional.
+    if (NS_SUCCEEDED(rv)) {
+      rv = stmt->BindStringByName("rev_host"_ns, revHost);
+    } else {
+      rv = stmt->BindNullByName("rev_host"_ns);
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindInt32ByName("hidden"_ns, 1);
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsAutoCString spec;
+    rv = aURI->GetSpec(spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindInt32ByName("frecency"_ns, IsQueryURI(spec) ? 0 : -1);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = GenerateGUID(_GUID);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rv = stmt->BindUTF8StringByName("guid"_ns, _GUID);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = stmt->Execute();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    *_pageId = sLastInsertedPlaceId;
+  }
+
+  return NS_OK;
+}
+
+void nsNavHistory::LoadPrefs() {
+  // History preferences.
+  mHistoryEnabled = Preferences::GetBool(PREF_HISTORY_ENABLED, true);
+  mMatchDiacritics = Preferences::GetBool(PREF_MATCH_DIACRITICS, false);
+
+  // Frecency preferences.
+#define FRECENCY_PREF(_prop, _pref) \
+  _prop = Preferences::GetInt(_pref, _pref##_DEF)
+
+  FRECENCY_PREF(mNumVisitsForFrecency, PREF_FREC_NUM_VISITS);
+  FRECENCY_PREF(mFirstBucketCutoffInDays, PREF_FREC_FIRST_BUCKET_CUTOFF);
+  FRECENCY_PREF(mSecondBucketCutoffInDays, PREF_FREC_SECOND_BUCKET_CUTOFF);
+  FRECENCY_PREF(mThirdBucketCutoffInDays, PREF_FREC_THIRD_BUCKET_CUTOFF);
+  FRECENCY_PREF(mFourthBucketCutoffInDays, PREF_FREC_FOURTH_BUCKET_CUTOFF);
+  FRECENCY_PREF(mEmbedVisitBonus, PREF_FREC_EMBED_VISIT_BONUS);
+  FRECENCY_PREF(mFramedLinkVisitBonus, PREF_FREC_FRAMED_LINK_VISIT_BONUS);
+  FRECENCY_PREF(mLinkVisitBonus, PREF_FREC_LINK_VISIT_BONUS);
+  FRECENCY_PREF(mTypedVisitBonus, PREF_FREC_TYPED_VISIT_BONUS);
+  FRECENCY_PREF(mBookmarkVisitBonus, PREF_FREC_BOOKMARK_VISIT_BONUS);
+  FRECENCY_PREF(mDownloadVisitBonus, PREF_FREC_DOWNLOAD_VISIT_BONUS);
+  FRECENCY_PREF(mPermRedirectVisitBonus, PREF_FREC_PERM_REDIRECT_VISIT_BONUS);
+  FRECENCY_PREF(mTempRedirectVisitBonus, PREF_FREC_TEMP_REDIRECT_VISIT_BONUS);
+  FRECENCY_PREF(mRedirectSourceVisitBonus, PREF_FREC_REDIR_SOURCE_VISIT_BONUS);
+  FRECENCY_PREF(mDefaultVisitBonus, PREF_FREC_DEFAULT_VISIT_BONUS);
+  FRECENCY_PREF(mUnvisitedBookmarkBonus, PREF_FREC_UNVISITED_BOOKMARK_BONUS);
+  FRECENCY_PREF(mUnvisitedTypedBonus, PREF_FREC_UNVISITED_TYPED_BONUS);
+  FRECENCY_PREF(mReloadVisitBonus, PREF_FREC_RELOAD_VISIT_BONUS);
+  FRECENCY_PREF(mFirstBucketWeight, PREF_FREC_FIRST_BUCKET_WEIGHT);
+  FRECENCY_PREF(mSecondBucketWeight, PREF_FREC_SECOND_BUCKET_WEIGHT);
+  FRECENCY_PREF(mThirdBucketWeight, PREF_FREC_THIRD_BUCKET_WEIGHT);
+  FRECENCY_PREF(mFourthBucketWeight, PREF_FREC_FOURTH_BUCKET_WEIGHT);
+  FRECENCY_PREF(mDefaultWeight, PREF_FREC_DEFAULT_BUCKET_WEIGHT);
+
+#undef FRECENCY_PREF
+}
+
+void nsNavHistory::UpdateDaysOfHistory(PRTime visitTime) {
+  if (sDaysOfHistory == 0) {
+    sDaysOfHistory = 1;
+  }
+
+  if (visitTime > mLastCachedEndOfDay || visitTime < mLastCachedStartOfDay) {
+    InvalidateDaysOfHistory();
+  }
+}
+
+/** static */
+nsLiteralCString nsNavHistory::GetTagsSqlFragment(const uint16_t aQueryType,
+                                                  bool aExcludeItems) {
+  if (aQueryType != nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS ||
+      aExcludeItems) {
+    return "WITH tagged(place_id, tags) AS (VALUES(NULL, NULL)) "_ns;
+  }
+  return "WITH tagged(place_id, tags) AS ( "
+         "  SELECT b.fk, group_concat(p.title ORDER BY p.title) "
+         "  FROM moz_bookmarks b "
+         "  JOIN moz_bookmarks p ON p.id = b.parent "
+         "  JOIN moz_bookmarks g ON g.id = p.parent "
+         "  WHERE g.guid = " SQL_QUOTE(TAGS_ROOT_GUID)
+         "  GROUP BY b.fk "
+         ") "_ns;
+}
+
+/* static */
+mozilla::Maybe<nsCString> nsNavHistory::GetTargetFolderGuid(
+    const nsACString& aQueryURI) {
+  nsCOMPtr<nsINavHistoryQuery> query;
+  nsCOMPtr<nsINavHistoryQueryOptions> options;
+  if (!IsQueryURI(aQueryURI) ||
+      NS_FAILED(nsNavHistoryQuery::QueryStringToQuery(
+          aQueryURI, getter_AddRefs(query), getter_AddRefs(options)))) {
+    return Nothing();
+  }
+
+  RefPtr<nsNavHistoryQuery> queryObj = do_QueryObject(query);
+  RefPtr<nsNavHistoryQueryOptions> optionsObj = do_QueryObject(options);
+  if (!queryObj || !optionsObj) {
+    return Nothing();
+  }
+
+  return GetSimpleBookmarksQueryParent(queryObj, optionsObj);
+}
+
+Atomic<int64_t> nsNavHistory::sLastInsertedPlaceId(0);
+Atomic<int64_t> nsNavHistory::sLastInsertedVisitId(0);
+Atomic<bool> nsNavHistory::sIsFrecencyDecaying(false);
+Atomic<bool> nsNavHistory::sShouldStartFrecencyRecalculation(false);
+
+void  // static
+nsNavHistory::StoreLastInsertedId(const nsACString& aTable,
+                                  const int64_t aLastInsertedId) {
+  if (aTable.EqualsLiteral("moz_places")) {
+    nsNavHistory::sLastInsertedPlaceId = aLastInsertedId;
+  } else if (aTable.EqualsLiteral("moz_historyvisits")) {
+    nsNavHistory::sLastInsertedVisitId = aLastInsertedId;
+  } else {
+    MOZ_ASSERT(false, "Trying to store the insert id for an unknown table?");
+  }
+}
+
+Atomic<int32_t> nsNavHistory::sDaysOfHistory(-1);
+
+void  // static
+nsNavHistory::InvalidateDaysOfHistory() {
+  sDaysOfHistory = -1;
+}
+
+int32_t nsNavHistory::GetDaysOfHistory() {
+  MOZ_ASSERT(NS_IsMainThread(), "This can only be called on the main thread");
+
+  if (sDaysOfHistory != -1) return sDaysOfHistory;
+
+  // SQLite doesn't have a CEIL() function, so we must do that later.
+  // We should also take into account timers resolution, that may be as bad as
+  // 16ms on Windows, so in some cases the difference may be 0, if the
+  // check is done near the visit.  Thus remember to check for NULL separately.
+  nsCOMPtr<mozIStorageStatement> stmt = mDB->GetStatement(
+      "SELECT CAST(( "
+      "strftime('%s','now','localtime','utc') - "
+      "(SELECT MIN(visit_date)/1000000 FROM moz_historyvisits) "
+      ") AS DOUBLE) "
+      "/86400, "
+      "strftime('%s','now','localtime','+1 day','start of day','utc') * "
+      "1000000");
+  NS_ENSURE_TRUE(stmt, 0);
+  mozStorageStatementScoper scoper(stmt);
+
+  bool hasResult;
+  if (NS_SUCCEEDED(stmt->ExecuteStep(&hasResult)) && hasResult) {
+    // If we get NULL, then there are no visits, otherwise there must always be
+    // at least 1 day of history.
+    bool hasNoVisits;
+    (void)stmt->GetIsNull(0, &hasNoVisits);
+    sDaysOfHistory =
+        hasNoVisits
+            ? 0
+            : std::max(1, static_cast<int32_t>(ceil(stmt->AsDouble(0))));
+    mLastCachedStartOfDay =
+        NormalizeTime(nsINavHistoryQuery::TIME_RELATIVE_TODAY, 0);
+    mLastCachedEndOfDay = stmt->AsInt64(1) - 1;  // Start of tomorrow - 1.
+  }
+
+  return sDaysOfHistory;
+}
+
+PRTime nsNavHistory::GetNow() {
+  if (!mCachedNow) {
+    mCachedNow = PR_Now();
+    if (!mExpireNowTimer) mExpireNowTimer = NS_NewTimer();
+    if (mExpireNowTimer)
+      mExpireNowTimer->InitWithNamedFuncCallback(
+          expireNowTimerCallback, this, RENEW_CACHED_NOW_TIMEOUT,
+          nsITimer::TYPE_ONE_SHOT, "nsNavHistory::GetNow");
+  }
+  return mCachedNow;
+}
+
+void nsNavHistory::expireNowTimerCallback(nsITimer* aTimer, void* aClosure) {
+  nsNavHistory* history = static_cast<nsNavHistory*>(aClosure);
+  if (history) {
+    history->mCachedNow = 0;
+    history->mExpireNowTimer = nullptr;
+  }
+}
+
+/**
+ * Code borrowed from mozilla/xpfe/components/history/src/nsGlobalHistory.cpp
+ * Pass in a pre-normalized now and a date, and we'll find the difference since
+ * midnight on each of the days.
+ */
+static PRTime NormalizeTimeRelativeToday(PRTime aTime) {
+  // round to midnight this morning
+  PRExplodedTime explodedTime;
+  PR_ExplodeTime(aTime, PR_LocalTimeParameters, &explodedTime);
+
+  // set to midnight (0:00)
+  explodedTime.tm_min = explodedTime.tm_hour = explodedTime.tm_sec =
+      explodedTime.tm_usec = 0;
+
+  return PR_ImplodeTime(&explodedTime);
+}
+
+// nsNavHistory::NormalizeTime
+//
+//    Converts a nsINavHistoryQuery reference+offset time into a PRTime
+//    relative to the epoch.
+//
+//    It is important that this function NOT use the current time optimization.
+//    It is called to update queries, and we really need to know what right
+//    now is because those incoming values will also have current times that
+//    we will have to compare against.
+
+PRTime  // static
+nsNavHistory::NormalizeTime(uint32_t aRelative, PRTime aOffset) {
+  PRTime ref;
+  switch (aRelative) {
+    case nsINavHistoryQuery::TIME_RELATIVE_EPOCH:
+      return aOffset;
+    case nsINavHistoryQuery::TIME_RELATIVE_TODAY:
+      ref = NormalizeTimeRelativeToday(PR_Now());
+      break;
+    case nsINavHistoryQuery::TIME_RELATIVE_NOW:
+      ref = PR_Now();
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Invalid relative time");
+      return 0;
+  }
+  return ref + aOffset;
+}
+
+// nsNavHistory::DomainNameFromURI
+//
+//    This does the www.mozilla.org -> mozilla.org and
+//    foo.theregister.co.uk -> theregister.co.uk conversion
+void nsNavHistory::DomainNameFromURI(nsIURI* aURI, nsACString& aDomainName) {
+  // lazily get the effective tld service
+  if (!mTLDService)
+    mTLDService = do_GetService(NS_EFFECTIVETLDSERVICE_CONTRACTID);
+
+  if (mTLDService) {
+    // get the base domain for a given hostname.
+    // e.g. for "images.bbc.co.uk", this would be "bbc.co.uk".
+    nsresult rv = mTLDService->GetBaseDomain(aURI, 0, aDomainName);
+    if (NS_SUCCEEDED(rv)) return;
+  }
+
+  // just return the original hostname
+  // (it's also possible the host is an IP address)
+  aURI->GetAsciiHost(aDomainName);
+}
+
+bool nsNavHistory::hasHistoryEntries() { return GetDaysOfHistory() > 0; }
+
+// Call this method before visiting a URL in order to help determine the
+// transition type of the visit.
+//
+// @see MarkPageAsTyped
+
+NS_IMETHODIMP
+nsNavHistory::MarkPageAsFollowedBookmark(nsIURI* aURI) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aURI);
+
+  // don't add when history is disabled
+  if (IsHistoryDisabled()) return NS_OK;
+
+  nsAutoCString uriString;
+  nsresult rv = aURI->GetSpec(uriString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mRecentBookmark.InsertOrUpdate(uriString, GetNow());
+
+  if (mRecentBookmark.Count() > RECENT_EVENT_QUEUE_MAX_LENGTH)
+    ExpireNonrecentEvents(&mRecentBookmark);
+
+  return NS_OK;
+}
+
+// nsNavHistory::CanAddURI
+//
+//    Filter out unwanted URIs such as "chrome:", "mailbox:", etc.
+//
+//    The model is if we don't know differently then add which basically means
+//    we are suppose to try all the things we know not to allow in and then if
+//    we don't bail go on and allow it in.
+
+NS_IMETHODIMP
+nsNavHistory::CanAddURI(nsIURI* aURI, bool* canAdd) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aURI);
+  NS_ENSURE_ARG_POINTER(canAdd);
+
+  // If history is disabled, don't add any entry.
+  *canAdd = !IsHistoryDisabled() && BaseHistory::CanStore(aURI);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetNewQuery(nsINavHistoryQuery** _retval) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  RefPtr<nsNavHistoryQuery> query = new nsNavHistoryQuery();
+  query.forget(_retval);
+  return NS_OK;
+}
+
+// nsNavHistory::GetNewQueryOptions
+
+NS_IMETHODIMP
+nsNavHistory::GetNewQueryOptions(nsINavHistoryQueryOptions** _retval) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  RefPtr<nsNavHistoryQueryOptions> queryOptions =
+      new nsNavHistoryQueryOptions();
+  queryOptions.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::ExecuteQuery(nsINavHistoryQuery* aQuery,
+                           nsINavHistoryQueryOptions* aOptions,
+                           nsINavHistoryResult** _retval) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aQuery);
+  NS_ENSURE_ARG(aOptions);
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  // Clone the input query and options, because the caller might change the
+  // objects, but we always want to reflect the original parameters.
+  nsCOMPtr<nsINavHistoryQuery> queryClone;
+  aQuery->Clone(getter_AddRefs(queryClone));
+  NS_ENSURE_STATE(queryClone);
+  RefPtr<nsNavHistoryQuery> query = do_QueryObject(queryClone);
+  NS_ENSURE_STATE(query);
+  nsCOMPtr<nsINavHistoryQueryOptions> optionsClone;
+  aOptions->Clone(getter_AddRefs(optionsClone));
+  NS_ENSURE_STATE(optionsClone);
+  RefPtr<nsNavHistoryQueryOptions> options = do_QueryObject(optionsClone);
+  NS_ENSURE_STATE(options);
+
+  // Create the root node.
+  RefPtr<nsNavHistoryContainerResultNode> rootNode;
+
+  Maybe<nsCString> targetFolderGuid =
+      GetSimpleBookmarksQueryParent(query, options);
+  if (targetFolderGuid.isSome()) {
+    int32_t targetFolderType = 0;
+    int64_t targetFolderId = -1;
+    nsCString targetFolderTitle;
+    PRTime dateAdded;
+    PRTime lastModified;
+    nsresult rv =
+        FetchInfo(mDB, *targetFolderGuid, targetFolderType, targetFolderId,
+                  targetFolderTitle, dateAdded, lastModified);
+    if (NS_SUCCEEDED(rv) &&
+        targetFolderType == nsINavBookmarksService::TYPE_FOLDER) {
+      auto* node = new nsNavHistoryFolderResultNode(
+          targetFolderId, *targetFolderGuid, targetFolderId, *targetFolderGuid,
+          targetFolderTitle, options);
+      node->mDateAdded = dateAdded;
+      node->mLastModified = lastModified;
+      rootNode = node->GetAsContainer();
+    } else {
+      NS_WARNING("Generating a generic empty node for a broken query!");
+      // This is a perf hack to generate an empty query that skips filtering.
+      options->SetExcludeItems(true);
+    }
+  }
+
+  if (!rootNode) {
+    // Either this is not a folder shortcut, or is a broken one.  In both cases
+    // just generate a query node.
+    nsAutoCString queryUri;
+    nsresult rv = QueryToQueryString(query, options, queryUri);
+    NS_ENSURE_SUCCESS(rv, rv);
+    rootNode =
+        new nsNavHistoryQueryResultNode(""_ns, 0, queryUri, query, options);
+  }
+
+  // Create the result that will hold nodes.  Inject batching status into it.
+  RefPtr<nsNavHistoryResult> result =
+      new nsNavHistoryResult(rootNode, query, options);
+  result.forget(_retval);
+  return NS_OK;
+}
+
+// determine from our nsNavHistoryQuery array and nsNavHistoryQueryOptions
+// if this is the place query from the history menu.
+// from browser-menubar.inc, our history menu query is:
+// place:sort=4&maxResults=10
+// note, any maxResult > 0 will still be considered a history menu query
+// or if this is the place query from the old "Most Visited" item in some
+// profiles: folder: place:sort=8&maxResults=10 note, any maxResult > 0 will
+// still be considered a Most Visited menu query
+static bool IsOptimizableHistoryQuery(
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions, uint16_t aSortMode) {
+  if (aOptions->QueryType() != nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY)
+    return false;
+
+  if (aOptions->ResultType() != nsINavHistoryQueryOptions::RESULTS_AS_URI)
+    return false;
+
+  if (aOptions->SortingMode() != aSortMode) return false;
+
+  if (aOptions->MaxResults() <= 0) return false;
+
+  if (aOptions->ExcludeItems()) return false;
+
+  if (aOptions->IncludeHidden()) return false;
+
+  if (aQuery->MinVisits() != -1 || aQuery->MaxVisits() != -1) return false;
+
+  if (aQuery->BeginTime() || aQuery->BeginTimeReference()) return false;
+
+  if (aQuery->EndTime() || aQuery->EndTimeReference()) return false;
+
+  if (!aQuery->SearchTerms().IsEmpty()) return false;
+
+  if (aQuery->DomainIsHost() || !aQuery->Domain().IsEmpty()) return false;
+
+  if (aQuery->Parents().Length() > 0) return false;
+
+  if (aQuery->Tags().Length() > 0) return false;
+
+  if (aQuery->Transitions().Length() > 0) return false;
+
+  return true;
+}
+
+static bool NeedToFilterResultSet(const RefPtr<nsNavHistoryQuery>& aQuery,
+                                  nsNavHistoryQueryOptions* aOptions) {
+  return aOptions->ExcludeQueries();
+}
+
+// ** Helper class for ConstructQueryString **/
+
+class PlacesSQLQueryBuilder {
+ public:
+  PlacesSQLQueryBuilder(const nsCString& aConditions,
+                        const RefPtr<nsNavHistoryQuery>& aQuery,
+                        const RefPtr<nsNavHistoryQueryOptions>& aOptions,
+                        bool aUseLimit, nsNavHistory::StringHash& aAddParams);
+
+  nsresult GetQueryString(nsCString& aQueryString);
+
+ private:
+  nsresult Select();
+
+  nsresult SelectAsURI();
+  nsresult SelectAsVisit();
+  nsresult SelectAsDay();
+  nsresult SelectAsSite();
+  nsresult SelectAsTag();
+  nsresult SelectAsRoots();
+  nsresult SelectAsLeftPane();
+
+  nsresult Where();
+  nsresult GroupBy();
+  nsresult OrderBy();
+  nsresult Limit();
+
+  void OrderByColumnIndexAsc(int32_t aIndex);
+  void OrderByColumnIndexDesc(int32_t aIndex);
+  // Use these if you want a case insensitive sorting.
+  void OrderByTextColumnIndexAsc(int32_t aIndex);
+  void OrderByTextColumnIndexDesc(int32_t aIndex);
+
+  const nsCString& mConditions;
+  bool mUseLimit;
+
+  uint16_t mResultType;
+  uint16_t mQueryType;
+  bool mExcludeItems;
+  bool mIncludeHidden;
+  uint16_t mSortingMode;
+  uint32_t mMaxResults;
+
+  nsCString mQueryString;
+  nsCString mGroupBy;
+  bool mHasDateColumns;
+  bool mSkipOrderBy;
+
+  nsNavHistory::StringHash& mAddParams;
+};
+
+PlacesSQLQueryBuilder::PlacesSQLQueryBuilder(
+    const nsCString& aConditions, const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions, bool aUseLimit,
+    nsNavHistory::StringHash& aAddParams)
+    : mConditions(aConditions),
+      mUseLimit(aUseLimit),
+      mResultType(aOptions->ResultType()),
+      mQueryType(aOptions->QueryType()),
+      mExcludeItems(aOptions->ExcludeItems()),
+      mIncludeHidden(aOptions->IncludeHidden()),
+      mSortingMode(aOptions->SortingMode()),
+      mMaxResults(aOptions->MaxResults()),
+      mSkipOrderBy(false),
+      mAddParams(aAddParams) {
+  mHasDateColumns =
+      (mQueryType == nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS);
+  // Force the default sorting mode for tag queries.
+  if (mSortingMode == nsINavHistoryQueryOptions::SORT_BY_NONE &&
+      aQuery->Tags().Length() > 0) {
+    mSortingMode = nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING;
+  }
+}
+
+nsresult PlacesSQLQueryBuilder::GetQueryString(nsCString& aQueryString) {
+  nsresult rv = Select();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = Where();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = GroupBy();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = OrderBy();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = Limit();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aQueryString = mQueryString;
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::Select() {
+  nsresult rv;
+
+  switch (mResultType) {
+    case nsINavHistoryQueryOptions::RESULTS_AS_URI:
+      rv = SelectAsURI();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_VISIT:
+      rv = SelectAsVisit();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY:
+    case nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY:
+      rv = SelectAsDay();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_SITE_QUERY:
+      rv = SelectAsSite();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT:
+      rv = SelectAsTag();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY:
+      rv = SelectAsRoots();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    case nsINavHistoryQueryOptions::RESULTS_AS_LEFT_PANE_QUERY:
+      rv = SelectAsLeftPane();
+      NS_ENSURE_SUCCESS(rv, rv);
+      break;
+
+    default:
+      MOZ_ASSERT_UNREACHABLE("Invalid result type");
+  }
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsURI() {
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+
+  switch (mQueryType) {
+    case nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY: {
+      mQueryString =
+          nsNavHistory::GetTagsSqlFragment(mQueryType, mExcludeItems) +
+          "SELECT h.id, h.url, h.title AS page_title, h.rev_host, "
+          "  h.visit_count, h.last_visit_date, null, null, null, null, null, "
+          "  (SELECT tags FROM tagged WHERE place_id = h.id) AS tags, "
+          "  h.frecency, h.hidden, h.guid, null, null, null, "
+          "  null, null, null, null, null, null, null "
+          "FROM moz_places h "
+          // WHERE 1 is a no-op since additonal conditions will
+          // start with AND.
+          "WHERE 1 "
+          "{QUERY_OPTIONS_VISITS} {QUERY_OPTIONS_PLACES} "
+          "{ADDITIONAL_CONDITIONS} "_ns;
+      break;
+    }
+    case nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS: {
+      mQueryString =
+          nsNavHistory::GetTagsSqlFragment(mQueryType, mExcludeItems) +
+          "SELECT b.fk, h.url, b.title AS page_title, "
+          "  h.rev_host, h.visit_count, h.last_visit_date, null, b.id, "
+          "  b.dateAdded, b.lastModified, b.parent, "
+          "  (SELECT tags FROM tagged WHERE place_id = h.id) AS tags, "
+          "  h.frecency, h.hidden, h.guid, null, null, null, b.guid, "
+          "  b.position, b.type, b.fk, t.guid, t.id, t.title "
+          "FROM moz_bookmarks b "
+          "JOIN moz_places h ON b.fk = h.id "
+          "LEFT JOIN moz_bookmarks t ON t.guid = target_folder_guid(h.url) "
+          "WHERE NOT EXISTS "
+          "(SELECT id FROM moz_bookmarks "
+          "WHERE id = b.parent AND parent = "_ns +
+          nsPrintfCString("%" PRId64, history->GetTagsFolder()) +
+          ") "
+          "AND NOT h.url_hash BETWEEN hash('place', 'prefix_lo') "
+          "                       AND hash('place', 'prefix_hi') "
+          "{ADDITIONAL_CONDITIONS}"_ns;
+      break;
+    }
+    default: {
+      return NS_ERROR_NOT_IMPLEMENTED;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsVisit() {
+  mQueryString =
+      nsNavHistory::GetTagsSqlFragment(mQueryType, mExcludeItems) +
+      "SELECT h.id, h.url, h.title AS page_title, h.rev_host, h.visit_count, "
+      "  v.visit_date, null, null, null, null, null, "
+      "  (SELECT tags FROM tagged WHERE place_id = h.id) AS tags, "
+      "  h.frecency, h.hidden, h.guid, v.id, v.from_visit, v.visit_type, "
+      "  null, null, null, null, null, null, null "
+      "FROM moz_places h "
+      "JOIN moz_historyvisits v ON h.id = v.place_id "
+      // WHERE 1 is a no-op since additonal conditions will start with AND.
+      "WHERE 1 "
+      "{QUERY_OPTIONS_VISITS} {QUERY_OPTIONS_PLACES} "
+      "{ADDITIONAL_CONDITIONS} "_ns;
+
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsDay() {
+  mSkipOrderBy = true;
+
+  // Sort child queries based on sorting mode if it's provided, otherwise
+  // fallback to default sort by title ascending.
+  uint16_t sortingMode = nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING;
+  if (mSortingMode != nsINavHistoryQueryOptions::SORT_BY_NONE &&
+      mResultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY)
+    sortingMode = mSortingMode;
+
+  uint16_t resultType =
+      mResultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY
+          ? (uint16_t)nsINavHistoryQueryOptions::RESULTS_AS_URI
+          : (uint16_t)nsINavHistoryQueryOptions::RESULTS_AS_SITE_QUERY;
+
+  // beginTime will become the node's time property, we don't use endTime
+  // because it could overlap, and we use time to sort containers and find
+  // insert position in a result.
+  mQueryString = nsPrintfCString(
+      "SELECT null, "
+      "'place:type=%d&sort=%d&beginTime='||beginTime||'&endTime='||endTime, "
+      "dayTitle, null, null, beginTime, null, null, null, null, null, null, "
+      "null, null, null, null, null, null, null, null, null, null, "
+      "null, null, null "
+      "FROM (",  // TOUTER BEGIN
+      resultType, sortingMode);
+
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_STATE(history);
+
+  int32_t daysOfHistory = history->GetDaysOfHistory();
+  for (int32_t i = 0; i <= HISTORY_DATE_CONT_NUM(daysOfHistory); i++) {
+    nsAutoCString dateName;
+    // Timeframes are calculated as BeginTime <= container < EndTime.
+    // Notice times can't be relative to now, since to recognize a query we
+    // must ensure it won't change based on the time it is built.
+    // So, to select till now, we really select till start of tomorrow, that is
+    // a fixed timestamp.
+    // These are used as limits for the inside containers.
+    nsAutoCString sqlFragmentContainerBeginTime, sqlFragmentContainerEndTime;
+    // These are used to query if the container should be visible.
+    nsAutoCString sqlFragmentSearchBeginTime, sqlFragmentSearchEndTime;
+    switch (i) {
+      case 0:
+        // Today
+        history->GetStringFromName("finduri-AgeInDays-is-0", dateName);
+        // From start of today
+        sqlFragmentContainerBeginTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','utc')*1000000)");
+        // To now (tomorrow)
+        sqlFragmentContainerEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','+1 "
+            "day','utc')*1000000)");
+        // Search for the same timeframe.
+        sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+        sqlFragmentSearchEndTime = sqlFragmentContainerEndTime;
+        break;
+      case 1:
+        // Yesterday
+        history->GetStringFromName("finduri-AgeInDays-is-1", dateName);
+        // From start of yesterday
+        sqlFragmentContainerBeginTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','-1 "
+            "day','utc')*1000000)");
+        // To start of today
+        sqlFragmentContainerEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','utc')*1000000)");
+        // Search for the same timeframe.
+        sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+        sqlFragmentSearchEndTime = sqlFragmentContainerEndTime;
+        break;
+      case 2:
+        // Last 7 days
+        history->GetAgeInDaysString(7, "finduri-AgeInDays-last-is", dateName);
+        // From start of 7 days ago
+        sqlFragmentContainerBeginTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','-7 "
+            "days','utc')*1000000)");
+        // To now (tomorrow)
+        sqlFragmentContainerEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','+1 "
+            "day','utc')*1000000)");
+        // This is an overlapped container, but we show it only if there are
+        // visits older than yesterday.
+        sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+        sqlFragmentSearchEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','-1 "
+            "day','utc')*1000000)");
+        break;
+      case 3:
+        // This month
+        history->GetStringFromName("finduri-AgeInMonths-is-0", dateName);
+        // From start of this month
+        sqlFragmentContainerBeginTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of "
+            "month','utc')*1000000)");
+        // To now (tomorrow)
+        sqlFragmentContainerEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','+1 "
+            "day','utc')*1000000)");
+        // This is an overlapped container, but we show it only if there are
+        // visits older than 7 days ago.
+        sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+        sqlFragmentSearchEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of day','-7 "
+            "days','utc')*1000000)");
+        break;
+      default:
+        if (i == HISTORY_ADDITIONAL_DATE_CONT_NUM + 6) {
+          // Older than 6 months
+          history->GetAgeInDaysString(6, "finduri-AgeInMonths-isgreater",
+                                      dateName);
+          // From start of epoch
+          sqlFragmentContainerBeginTime =
+              "(datetime(0, 'unixepoch')*1000000)"_ns;
+          // To start of 6 months ago ( 5 months + this month).
+          sqlFragmentContainerEndTime = nsLiteralCString(
+              "(strftime('%s','now','localtime','start of month','-5 "
+              "months','utc')*1000000)");
+          // Search for the same timeframe.
+          sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+          sqlFragmentSearchEndTime = sqlFragmentContainerEndTime;
+          break;
+        }
+        int32_t MonthIndex = i - HISTORY_ADDITIONAL_DATE_CONT_NUM;
+        // Previous months' titles are month's name if inside this year,
+        // month's name and year for previous years.
+        PRExplodedTime tm;
+        PR_ExplodeTime(PR_Now(), PR_LocalTimeParameters, &tm);
+        uint16_t currentYear = tm.tm_year;
+        // Set day before month, setting month without day could cause issues.
+        // For example setting month to February when today is 30, since
+        // February has not 30 days, will return March instead.
+        // Also, we use day 2 instead of day 1, so that the GMT month is always
+        // the same as the local month. (Bug 603002)
+        tm.tm_mday = 2;
+        tm.tm_month -= MonthIndex;
+        // Notice we use GMTParameters because we just want to get the first
+        // day of each month.  Using LocalTimeParameters would instead force us
+        // to apply a DST correction that we don't really need here.
+        PR_NormalizeTime(&tm, PR_GMTParameters);
+        // If the container is for a past year, add the year to its title,
+        // otherwise just show the month name.
+        if (tm.tm_year < currentYear) {
+          nsNavHistory::GetMonthYear(tm, dateName);
+        } else {
+          nsNavHistory::GetMonthName(tm, dateName);
+        }
+
+        // From start of MonthIndex + 1 months ago
+        sqlFragmentContainerBeginTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of month','-");
+        sqlFragmentContainerBeginTime.AppendInt(MonthIndex);
+        sqlFragmentContainerBeginTime.AppendLiteral(" months','utc')*1000000)");
+        // To start of MonthIndex months ago
+        sqlFragmentContainerEndTime = nsLiteralCString(
+            "(strftime('%s','now','localtime','start of month','-");
+        sqlFragmentContainerEndTime.AppendInt(MonthIndex - 1);
+        sqlFragmentContainerEndTime.AppendLiteral(" months','utc')*1000000)");
+        // Search for the same timeframe.
+        sqlFragmentSearchBeginTime = sqlFragmentContainerBeginTime;
+        sqlFragmentSearchEndTime = sqlFragmentContainerEndTime;
+        break;
+    }
+
+    nsPrintfCString dateParam("dayTitle%d", i);
+    mAddParams.InsertOrUpdate(dateParam, dateName);
+
+    nsPrintfCString dayRange(
+        "SELECT :%s AS dayTitle, "
+        "%s AS beginTime, "
+        "%s AS endTime "
+        "WHERE EXISTS ( "
+        "SELECT id FROM moz_historyvisits "
+        "WHERE visit_date >= %s "
+        "AND visit_date < %s "
+        "AND visit_type NOT IN (0,%d,%d) "
+        "{QUERY_OPTIONS_VISITS} "
+        "LIMIT 1 "
+        ") ",
+        dateParam.get(), sqlFragmentContainerBeginTime.get(),
+        sqlFragmentContainerEndTime.get(), sqlFragmentSearchBeginTime.get(),
+        sqlFragmentSearchEndTime.get(), nsINavHistoryService::TRANSITION_EMBED,
+        nsINavHistoryService::TRANSITION_FRAMED_LINK);
+
+    mQueryString.Append(dayRange);
+
+    if (i < HISTORY_DATE_CONT_NUM(daysOfHistory))
+      mQueryString.AppendLiteral(" UNION ALL ");
+  }
+
+  mQueryString.AppendLiteral(") ");  // TOUTER END
+
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsSite() {
+  nsAutoCString localFiles;
+
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_STATE(history);
+
+  history->GetStringFromName("localhost", localFiles);
+  mAddParams.InsertOrUpdate("localhost"_ns, localFiles);
+
+  // If there are additional conditions the query has to join on visits too.
+  nsAutoCString visitsJoin;
+  nsAutoCString additionalConditions;
+  nsAutoCString timeConstraints;
+  if (!mConditions.IsEmpty()) {
+    visitsJoin.AssignLiteral("JOIN moz_historyvisits v ON v.place_id = h.id ");
+    additionalConditions.AssignLiteral(
+        "{QUERY_OPTIONS_VISITS} "
+        "{QUERY_OPTIONS_PLACES} "
+        "{ADDITIONAL_CONDITIONS} ");
+    timeConstraints.AssignLiteral(
+        "||'&beginTime='||:begin_time||"
+        "'&endTime='||:end_time");
+  }
+
+  mQueryString = nsPrintfCString(
+      "SELECT null, 'place:type=%d&sort=%d&domain=&domainIsHost=true'%s, "
+      ":localhost, :localhost, null, null, null, null, null, null, null, "
+      "null, null, null, null, null, null, null, null, null, null, "
+      "null, null, null, null "
+      "WHERE EXISTS ( "
+      "SELECT h.id FROM moz_places h "
+      "%s "
+      "WHERE h.hidden = 0 "
+      "AND h.visit_count > 0 "
+      "AND h.url_hash BETWEEN hash('file', 'prefix_lo') AND "
+      "hash('file', 'prefix_hi') "
+      "%s "
+      "LIMIT 1 "
+      ") "
+      "UNION ALL "
+      "SELECT null, "
+      "'place:type=%d&sort=%d&domain='||host||'&domainIsHost=true'%s, "
+      "host, host, null, null, null, null, null, null, null, "
+      "null, null, null, null, null, null, null, null, null, null, "
+      "null, null, null, null "
+      "FROM ( "
+      "SELECT get_unreversed_host(h.rev_host) AS host "
+      "FROM moz_places h "
+      "%s "
+      "WHERE h.hidden = 0 "
+      "AND h.rev_host <> '.' "
+      "AND h.visit_count > 0 "
+      "%s "
+      "GROUP BY h.rev_host "
+      "ORDER BY host ASC "
+      ") ",
+      nsINavHistoryQueryOptions::RESULTS_AS_URI, mSortingMode,
+      timeConstraints.get(), visitsJoin.get(), additionalConditions.get(),
+      nsINavHistoryQueryOptions::RESULTS_AS_URI, mSortingMode,
+      timeConstraints.get(), visitsJoin.get(), additionalConditions.get());
+
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsTag() {
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_STATE(history);
+
+  // This allows sorting by date fields what is not possible with
+  // other history queries.
+  mHasDateColumns = true;
+
+  // TODO (Bug 1449939): This is likely wrong, since the tag name should
+  // probably be urlencoded, and we have no util for that in SQL, yet.
+  // We could encode the tag when the user sets it though.
+  mQueryString = nsPrintfCString(
+      "SELECT null, 'place:tag=' || title, "
+      "title, null, null, null, null, null, dateAdded, "
+      "lastModified, null, null, null, null, null, null, "
+      "null, null, null, null, null, null, null, null, null "
+      "FROM moz_bookmarks "
+      "WHERE parent = %" PRId64,
+      history->GetTagsFolder());
+
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsRoots() {
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_STATE(history);
+
+  nsAutoCString toolbarTitle;
+  nsAutoCString menuTitle;
+  nsAutoCString unfiledTitle;
+
+  history->GetStringFromName("BookmarksToolbarFolderTitle", toolbarTitle);
+  mAddParams.InsertOrUpdate("BookmarksToolbarFolderTitle"_ns, toolbarTitle);
+  history->GetStringFromName("BookmarksMenuFolderTitle", menuTitle);
+  mAddParams.InsertOrUpdate("BookmarksMenuFolderTitle"_ns, menuTitle);
+  history->GetStringFromName("OtherBookmarksFolderTitle", unfiledTitle);
+  mAddParams.InsertOrUpdate("OtherBookmarksFolderTitle"_ns, unfiledTitle);
+
+  nsAutoCString mobileString;
+
+  if (Preferences::GetBool(MOBILE_BOOKMARKS_PREF, false)) {
+    nsAutoCString mobileTitle;
+    history->GetStringFromName("MobileBookmarksFolderTitle", mobileTitle);
+    mAddParams.InsertOrUpdate("MobileBookmarksFolderTitle"_ns, mobileTitle);
+
+    mobileString = nsLiteralCString(
+        ","
+        "(null, 'place:parent=" MOBILE_ROOT_GUID
+        "', :MobileBookmarksFolderTitle, null, null, null, "
+        "null, null, 0, 0, null, null, null, null, "
+        SQL_QUOTE(MOBILE_BOOKMARKS_VIRTUAL_GUID) ", null, "
+        "null, null, null, null, null, null, " SQL_QUOTE(MOBILE_ROOT_GUID) ", "
+        "(SELECT id FROM moz_bookmarks WHERE guid = " SQL_QUOTE(MOBILE_ROOT_GUID) "), "
+        ":MobileBookmarksFolderTitle)");
+  }
+
+  mQueryString =
+      nsLiteralCString(
+          "SELECT * FROM ("
+          "VALUES(null, 'place:parent=" TOOLBAR_ROOT_GUID
+          "', :BookmarksToolbarFolderTitle, null, null, null, "
+          "null, null, 0, 0, null, null, null, null, 'toolbar____v', null, "
+          "null, null, null, null, null, null, " SQL_QUOTE(TOOLBAR_ROOT_GUID) ", "
+          "(SELECT id FROM moz_bookmarks WHERE guid = " SQL_QUOTE(TOOLBAR_ROOT_GUID) "), "
+          ":BookmarksToolbarFolderTitle), "
+          "(null, 'place:parent=" MENU_ROOT_GUID
+          "', :BookmarksMenuFolderTitle, null, null, null, "
+          "null, null, 0, 0, null, null, null, null, 'menu_______v', null, "
+          "null, null, null, null, null, null, " SQL_QUOTE(MENU_ROOT_GUID) ", "
+          "(SELECT id FROM moz_bookmarks WHERE guid = " SQL_QUOTE(MENU_ROOT_GUID) "), "
+          ":BookmarksMenuFolderTitle), "
+          "(null, 'place:parent=" UNFILED_ROOT_GUID
+          "', :OtherBookmarksFolderTitle, null, null, null, "
+          "null, null, 0, 0, null, null, null, null, 'unfiled____v', null, "
+          "null, null, null, null, null, null, " SQL_QUOTE(UNFILED_ROOT_GUID) ", "
+          "(SELECT id FROM moz_bookmarks WHERE guid = " SQL_QUOTE(UNFILED_ROOT_GUID) "), "
+          ":OtherBookmarksFolderTitle)") +
+      mobileString + ")"_ns;
+
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::SelectAsLeftPane() {
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_STATE(history);
+
+  nsAutoCString historyTitle;
+  nsAutoCString downloadsTitle;
+  nsAutoCString tagsTitle;
+  nsAutoCString allBookmarksTitle;
+
+  history->GetStringFromName("OrganizerQueryHistory", historyTitle);
+  mAddParams.InsertOrUpdate("OrganizerQueryHistory"_ns, historyTitle);
+  history->GetStringFromName("OrganizerQueryDownloads", downloadsTitle);
+  mAddParams.InsertOrUpdate("OrganizerQueryDownloads"_ns, downloadsTitle);
+  history->GetStringFromName("TagsFolderTitle", tagsTitle);
+  mAddParams.InsertOrUpdate("TagsFolderTitle"_ns, tagsTitle);
+  history->GetStringFromName("OrganizerQueryAllBookmarks", allBookmarksTitle);
+  mAddParams.InsertOrUpdate("OrganizerQueryAllBookmarks"_ns, allBookmarksTitle);
+
+  mQueryString = nsPrintfCString(
+      "SELECT * FROM ("
+      "VALUES"
+      "(null, 'place:type=%d&sort=%d', :OrganizerQueryHistory, null, null, "
+      "null, "
+      "null, null, 0, 0, null, null, null, null, 'history____v', null, "
+      "null, null, null, null, null, null, null), "
+      "(null, 'place:transition=%d&sort=%d', :OrganizerQueryDownloads, null, "
+      "null, null, "
+      "null, null, 0, 0, null, null, null, null, 'downloads__v', null, "
+      "null, null, null, null, null, null, null), "
+      "(null, 'place:type=%d&sort=%d', :TagsFolderTitle, null, null, null, "
+      "null, null, 0, 0, null, null, null, null, 'tags_______v', null, "
+      "null, null, null, null, null, null, null), "
+      "(null, 'place:type=%d', :OrganizerQueryAllBookmarks, null, null, null, "
+      "null, null, 0, 0, null, null, null, null, 'allbms_____v', null, "
+      "null, null, null, null, null, null, null) "
+      ")",
+      nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY,
+      nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING,
+      nsINavHistoryService::TRANSITION_DOWNLOAD,
+      nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING,
+      nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT,
+      nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING,
+      nsINavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY);
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::Where() {
+  // Set query options
+  nsAutoCString additionalVisitsConditions;
+  nsAutoCString additionalPlacesConditions;
+
+  if (!mIncludeHidden) {
+    additionalPlacesConditions += "AND hidden = 0 "_ns;
+  }
+
+  if (mQueryType == nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY) {
+    // last_visit_date is updated for any kind of visit, so it's a good
+    // indicator whether the page has visits.
+    additionalPlacesConditions += "AND last_visit_date NOTNULL "_ns;
+  }
+
+  if (mResultType == nsINavHistoryQueryOptions::RESULTS_AS_URI &&
+      !additionalVisitsConditions.IsEmpty()) {
+    // URI results don't join on visits.
+    nsAutoCString tmp = additionalVisitsConditions;
+    additionalVisitsConditions =
+        "AND EXISTS (SELECT 1 FROM moz_historyvisits WHERE place_id = h.id ";
+    additionalVisitsConditions.Append(tmp);
+    additionalVisitsConditions.AppendLiteral("LIMIT 1)");
+  }
+
+  mQueryString.ReplaceSubstring("{QUERY_OPTIONS_VISITS}",
+                                additionalVisitsConditions.get());
+  mQueryString.ReplaceSubstring("{QUERY_OPTIONS_PLACES}",
+                                additionalPlacesConditions.get());
+
+  // If we used WHERE already, we inject the conditions
+  // in place of {ADDITIONAL_CONDITIONS}
+  if (mQueryString.Find("{ADDITIONAL_CONDITIONS}") != kNotFound) {
+    nsAutoCString innerCondition;
+    // If we have condition AND it
+    if (!mConditions.IsEmpty()) {
+      innerCondition = " AND (";
+      innerCondition += mConditions;
+      innerCondition += ")";
+    }
+    mQueryString.ReplaceSubstring("{ADDITIONAL_CONDITIONS}",
+                                  innerCondition.get());
+
+  } else if (!mConditions.IsEmpty()) {
+    mQueryString += "WHERE ";
+    mQueryString += mConditions;
+  }
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::GroupBy() {
+  mQueryString += mGroupBy;
+  return NS_OK;
+}
+
+nsresult PlacesSQLQueryBuilder::OrderBy() {
+  if (mSkipOrderBy) return NS_OK;
+
+  // Sort clause: we will sort later, but if it comes out of the DB sorted,
+  // our later sort will be basically free. The DB can sort these for free
+  // most of the time anyway, because it has indices over these items.
+  switch (mSortingMode) {
+    case nsINavHistoryQueryOptions::SORT_BY_NONE:
+      // Ensure sorting does not change based on tables status.
+      if (mResultType == nsINavHistoryQueryOptions::RESULTS_AS_URI) {
+        if (mQueryType == nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS)
+          mQueryString += " ORDER BY b.id ASC "_ns;
+        else if (mQueryType == nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY)
+          mQueryString += " ORDER BY h.id ASC "_ns;
+      }
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING:
+    case nsINavHistoryQueryOptions::SORT_BY_TITLE_DESCENDING:
+      // If the user wants few results, we limit them by date, necessitating
+      // a sort by date here (see the IDL definition for maxResults).
+      // Otherwise we will do actual sorting by title, but since we could need
+      // to special sort for some locale we will repeat a second sorting at the
+      // end in nsNavHistoryResult, that should be faster since the list will be
+      // almost ordered.
+      if (mMaxResults > 0)
+        OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_VisitDate);
+      else if (mSortingMode ==
+               nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING)
+        OrderByTextColumnIndexAsc(nsNavHistory::kGetInfoIndex_Title);
+      else
+        OrderByTextColumnIndexDesc(nsNavHistory::kGetInfoIndex_Title);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING:
+      OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_VisitDate);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING:
+      OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_VisitDate);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_URI_ASCENDING:
+      OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_URL);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_URI_DESCENDING:
+      OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_URL);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING:
+      OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_VisitCount);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING:
+      OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_VisitCount);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_DATEADDED_ASCENDING:
+      if (mHasDateColumns)
+        OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_ItemDateAdded);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_DATEADDED_DESCENDING:
+      if (mHasDateColumns)
+        OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_ItemDateAdded);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_LASTMODIFIED_ASCENDING:
+      if (mHasDateColumns)
+        OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_ItemLastModified);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_LASTMODIFIED_DESCENDING:
+      if (mHasDateColumns)
+        OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_ItemLastModified);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_TAGS_ASCENDING:
+    case nsINavHistoryQueryOptions::SORT_BY_TAGS_DESCENDING:
+      break;  // Sort later in nsNavHistoryQueryResultNode::FillChildren()
+    case nsINavHistoryQueryOptions::SORT_BY_FRECENCY_ASCENDING:
+      OrderByColumnIndexAsc(nsNavHistory::kGetInfoIndex_Frecency);
+      break;
+    case nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING:
+      OrderByColumnIndexDesc(nsNavHistory::kGetInfoIndex_Frecency);
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Invalid sorting mode");
+  }
+  return NS_OK;
+}
+
+void PlacesSQLQueryBuilder::OrderByColumnIndexAsc(int32_t aIndex) {
+  mQueryString += nsPrintfCString(" ORDER BY %d ASC", aIndex + 1);
+}
+
+void PlacesSQLQueryBuilder::OrderByColumnIndexDesc(int32_t aIndex) {
+  mQueryString += nsPrintfCString(" ORDER BY %d DESC", aIndex + 1);
+}
+
+void PlacesSQLQueryBuilder::OrderByTextColumnIndexAsc(int32_t aIndex) {
+  mQueryString +=
+      nsPrintfCString(" ORDER BY %d COLLATE NOCASE ASC", aIndex + 1);
+}
+
+void PlacesSQLQueryBuilder::OrderByTextColumnIndexDesc(int32_t aIndex) {
+  mQueryString +=
+      nsPrintfCString(" ORDER BY %d COLLATE NOCASE DESC", aIndex + 1);
+}
+
+nsresult PlacesSQLQueryBuilder::Limit() {
+  if (mUseLimit && mMaxResults > 0) {
+    mQueryString += " LIMIT "_ns;
+    mQueryString.AppendInt(mMaxResults);
+    mQueryString.Append(' ');
+  }
+  return NS_OK;
+}
+
+nsresult nsNavHistory::ConstructQueryString(
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions, nsCString& queryString,
+    bool& aParamsPresent, nsNavHistory::StringHash& aAddParams) {
+  // For information about visit_type see nsINavHistoryService.idl.
+  // visitType == 0 is undefined (see bug #375777 for details).
+  // Some sites, especially Javascript-heavy ones, load things in frames to
+  // display them, resulting in a lot of these entries. This is the reason
+  // why such visits are filtered out.
+  nsresult rv;
+  aParamsPresent = false;
+
+  int32_t sortingMode = aOptions->SortingMode();
+  NS_ASSERTION(
+      sortingMode >= nsINavHistoryQueryOptions::SORT_BY_NONE &&
+          sortingMode <= nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING,
+      "Invalid sortingMode found while building query!");
+
+  if (IsOptimizableHistoryQuery(
+          aQuery, aOptions,
+          nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING) ||
+      IsOptimizableHistoryQuery(
+          aQuery, aOptions,
+          nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING)) {
+    // Generate an optimized query for the history menu and the old most visited
+    // bookmark that was inserted into profiles.
+    queryString =
+        GetTagsSqlFragment(aOptions->QueryType(), aOptions->ExcludeItems()) +
+        "SELECT h.id, h.url, h.title AS page_title, h.rev_host, "
+        "  h.visit_count, h.last_visit_date, null, null, null, null, null, "
+        "  (SELECT tags FROM tagged WHERE place_id = h.id) AS tags, "
+        "  h.frecency, h.hidden, h.guid, null, null, null, "
+        "  null, null, null, null, null, null, null "
+        "FROM moz_places h "
+        "WHERE h.hidden = 0 "
+        "AND EXISTS (SELECT id FROM moz_historyvisits WHERE place_id = "
+        "h.id "
+        "AND visit_type NOT IN "_ns +
+        nsPrintfCString("(0,%d,%d) ", nsINavHistoryService::TRANSITION_EMBED,
+                        nsINavHistoryService::TRANSITION_FRAMED_LINK) +
+        "LIMIT 1) "
+        "{QUERY_OPTIONS} "_ns;
+
+    queryString.AppendLiteral("ORDER BY ");
+    if (sortingMode == nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING)
+      queryString.AppendLiteral("last_visit_date DESC ");
+    else
+      queryString.AppendLiteral("visit_count DESC ");
+
+    queryString.AppendLiteral("LIMIT ");
+    queryString.AppendInt(aOptions->MaxResults());
+
+    nsAutoCString additionalQueryOptions;
+
+    queryString.ReplaceSubstring("{QUERY_OPTIONS}",
+                                 additionalQueryOptions.get());
+    return NS_OK;
+  }
+
+  // If the query is a tag query, the type is bookmarks.
+  if (!aQuery->Tags().IsEmpty()) {
+    aOptions->SetQueryType(nsNavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS);
+  }
+
+  nsAutoCString conditions;
+  nsCString queryClause;
+  rv = QueryToSelectClause(aQuery, aOptions, &queryClause);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!queryClause.IsEmpty()) {
+    // TODO: This should be set on a case basis, not blindly.
+    aParamsPresent = true;
+    conditions += queryClause;
+  }
+
+  // Determine whether we can push maxResults constraints into the query
+  // as LIMIT, or if we need to do result count clamping later
+  // using FilterResultSet()
+  bool useLimitClause = !NeedToFilterResultSet(aQuery, aOptions);
+
+  PlacesSQLQueryBuilder queryStringBuilder(conditions, aQuery, aOptions,
+                                           useLimitClause, aAddParams);
+  rv = queryStringBuilder.GetQueryString(queryString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+// nsNavHistory::GetQueryResults
+//
+//    Call this to get the results from a complex query. This is used by
+//    nsNavHistoryQueryResultNode to populate its children. For simple bookmark
+//    queries, use nsNavBookmarks::QueryFolderChildren.
+//
+//    THIS DOES NOT DO SORTING. You will need to sort the container yourself
+//    when you get the results. This is because sorting depends on tree
+//    statistics that will be built from the perspective of the tree. See
+//    nsNavHistoryQueryResultNode::FillChildren
+//
+//    FIXME: This only does keyword searching for the first query, and does
+//    it ANDed with the all the rest of the queries.
+
+nsresult nsNavHistory::GetQueryResults(
+    nsNavHistoryQueryResultNode* aResultNode,
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions,
+    nsCOMArray<nsNavHistoryResultNode>* aResults) {
+  NS_ENSURE_ARG_POINTER(aQuery);
+  NS_ENSURE_ARG_POINTER(aOptions);
+  NS_ASSERTION(aResults->Count() == 0, "Initial result array must be empty");
+
+  nsCString queryString;
+  bool paramsPresent = false;
+  nsNavHistory::StringHash addParams(HISTORY_DATE_CONT_LENGTH);
+  nsresult rv = ConstructQueryString(aQuery, aOptions, queryString,
+                                     paramsPresent, addParams);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // create statement
+  nsCOMPtr<mozIStorageStatement> statement = mDB->GetStatement(queryString);
+#ifdef DEBUG
+  if (!statement) {
+    nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
+    if (conn) {
+      nsAutoCString lastErrorString;
+      (void)conn->GetLastErrorString(lastErrorString);
+      int32_t lastError = 0;
+      (void)conn->GetLastError(&lastError);
+      printf(
+          "Places failed to create a statement from this query:\n%s\nStorage "
+          "error (%d): %s\n",
+          queryString.get(), lastError, lastErrorString.get());
+    }
+  }
+#endif
+  NS_ENSURE_STATE(statement);
+  mozStorageStatementScoper scoper(statement);
+
+  if (paramsPresent) {
+    rv = BindQueryClauseParameters(statement, aQuery, aOptions);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  for (const auto& entry : addParams) {
+    nsresult rv =
+        statement->BindUTF8StringByName(entry.GetKey(), entry.GetData());
+    if (NS_FAILED(rv)) {
+      break;
+    }
+  }
+
+  // Optimize the case where there is no need for any post-query filtering.
+  if (NeedToFilterResultSet(aQuery, aOptions)) {
+    // Generate the top-level results.
+    nsCOMArray<nsNavHistoryResultNode> toplevel;
+    rv = ResultsAsList(statement, aOptions, &toplevel);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    FilterResultSet(aResultNode, toplevel, aResults, aQuery, aOptions);
+  } else {
+    rv = ResultsAsList(statement, aOptions, aResults);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetHistoryDisabled(bool* _retval) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG_POINTER(_retval);
+
+  *_retval = IsHistoryDisabled();
+  return NS_OK;
+}
+
+// Call this method before visiting a URL in order to help determine the
+// transition type of the visit.
+//
+// @see MarkPageAsFollowedBookmark
+
+NS_IMETHODIMP
+nsNavHistory::MarkPageAsTyped(nsIURI* aURI) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aURI);
+
+  // don't add when history is disabled
+  if (IsHistoryDisabled()) return NS_OK;
+
+  nsAutoCString uriString;
+  nsresult rv = aURI->GetSpec(uriString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mRecentTyped.InsertOrUpdate(uriString, GetNow());
+
+  if (mRecentTyped.Count() > RECENT_EVENT_QUEUE_MAX_LENGTH)
+    ExpireNonrecentEvents(&mRecentTyped);
+
+  return NS_OK;
+}
+
+// Call this method before visiting a URL in order to help determine the
+// transition type of the visit.
+//
+// @see MarkPageAsTyped
+
+NS_IMETHODIMP
+nsNavHistory::MarkPageAsFollowedLink(nsIURI* aURI) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aURI);
+
+  // don't add when history is disabled
+  if (IsHistoryDisabled()) return NS_OK;
+
+  nsAutoCString uriString;
+  nsresult rv = aURI->GetSpec(uriString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mRecentLink.InsertOrUpdate(uriString, GetNow());
+
+  if (mRecentLink.Count() > RECENT_EVENT_QUEUE_MAX_LENGTH)
+    ExpireNonrecentEvents(&mRecentLink);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetIsFrecencyDecaying(bool* _out) {
+  NS_ENSURE_ARG_POINTER(_out);
+  *_out = nsNavHistory::sIsFrecencyDecaying;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::SetIsFrecencyDecaying(bool aVal) {
+  nsNavHistory::sIsFrecencyDecaying = aVal;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetShouldStartFrecencyRecalculation(bool* _out) {
+  NS_ENSURE_ARG_POINTER(_out);
+  *_out = nsNavHistory::sShouldStartFrecencyRecalculation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::SetShouldStartFrecencyRecalculation(bool aVal) {
+  nsNavHistory::sShouldStartFrecencyRecalculation = aVal;
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// mozIStorageVacuumParticipant
+
+NS_IMETHODIMP
+nsNavHistory::GetDatabaseConnection(
+    mozIStorageAsyncConnection** _DBConnection) {
+  NS_ENSURE_ARG_POINTER(_DBConnection);
+  nsCOMPtr<mozIStorageAsyncConnection> connection = mDB->MainConn();
+  connection.forget(_DBConnection);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetUseIncrementalVacuum(bool* _useIncremental) {
+  *_useIncremental = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetExpectedDatabasePageSize(int32_t* _expectedPageSize) {
+  NS_ENSURE_STATE(mDB);
+  NS_ENSURE_STATE(mDB->MainConn());
+  return mDB->MainConn()->GetDefaultPageSize(_expectedPageSize);
+}
+
+NS_IMETHODIMP
+nsNavHistory::OnBeginVacuum(bool* _vacuumGranted) {
+  // TODO: Check if we have to deny the vacuum in some heavy-load case.
+  // We could maybe want to do that during batches?
+  *_vacuumGranted = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::OnEndVacuum(bool aSucceeded) {
+  NS_WARNING_ASSERTION(aSucceeded, "Places.sqlite vacuum failed.");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetDBConnection(mozIStorageConnection** _DBConnection) {
+  NS_ENSURE_ARG_POINTER(_DBConnection);
+  nsCOMPtr<mozIStorageConnection> connection = mDB->MainConn();
+  connection.forget(_DBConnection);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetShutdownClient(nsIAsyncShutdownClient** _shutdownClient) {
+  NS_ENSURE_ARG_POINTER(_shutdownClient);
+  nsCOMPtr<nsIAsyncShutdownClient> client = mDB->GetClientsShutdown();
+  if (!client) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  client.forget(_shutdownClient);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::GetConnectionShutdownClient(
+    nsIAsyncShutdownClient** _shutdownClient) {
+  NS_ENSURE_ARG_POINTER(_shutdownClient);
+  nsCOMPtr<nsIAsyncShutdownClient> client = mDB->GetConnectionShutdown();
+  if (!client) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  client.forget(_shutdownClient);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::AsyncExecuteLegacyQuery(nsINavHistoryQuery* aQuery,
+                                      nsINavHistoryQueryOptions* aOptions,
+                                      mozIStorageStatementCallback* aCallback,
+                                      mozIStoragePendingStatement** _stmt) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  NS_ENSURE_ARG(aQuery);
+  NS_ENSURE_ARG(aOptions);
+  NS_ENSURE_ARG(aCallback);
+  NS_ENSURE_ARG_POINTER(_stmt);
+
+  RefPtr<nsNavHistoryQuery> query = do_QueryObject(aQuery);
+  NS_ENSURE_STATE(query);
+  RefPtr<nsNavHistoryQueryOptions> options = do_QueryObject(aOptions);
+  NS_ENSURE_ARG(options);
+
+  nsCString queryString;
+  bool paramsPresent = false;
+  nsNavHistory::StringHash addParams(HISTORY_DATE_CONT_LENGTH);
+  nsresult rv = ConstructQueryString(query, options, queryString, paramsPresent,
+                                     addParams);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<mozIStorageAsyncStatement> statement =
+      mDB->GetAsyncStatement(queryString);
+  NS_ENSURE_STATE(statement);
+
+#ifdef DEBUG
+  if (NS_FAILED(rv)) {
+    nsCOMPtr<mozIStorageConnection> conn = mDB->MainConn();
+    if (conn) {
+      nsAutoCString lastErrorString;
+      (void)mDB->MainConn()->GetLastErrorString(lastErrorString);
+      int32_t lastError = 0;
+      (void)mDB->MainConn()->GetLastError(&lastError);
+      printf(
+          "Places failed to create a statement from this query:\n%s\nStorage "
+          "error (%d): %s\n",
+          queryString.get(), lastError, lastErrorString.get());
+    }
+  }
+#endif
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (paramsPresent) {
+    rv = BindQueryClauseParameters(statement, query, options);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  for (const auto& entry : addParams) {
+    nsresult rv =
+        statement->BindUTF8StringByName(entry.GetKey(), entry.GetData());
+    if (NS_FAILED(rv)) {
+      break;
+    }
+  }
+
+  rv = statement->ExecuteAsync(aCallback, _stmt);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsIObserver
+
+NS_IMETHODIMP
+nsNavHistory::Observe(nsISupports* aSubject, const char* aTopic,
+                      const char16_t* aData) {
+  NS_ASSERTION(NS_IsMainThread(), "This can only be called on the main thread");
+  if (strcmp(aTopic, TOPIC_PROFILE_TEARDOWN) == 0 ||
+      strcmp(aTopic, TOPIC_PROFILE_CHANGE) == 0 ||
+      strcmp(aTopic, TOPIC_SIMULATE_PLACES_SHUTDOWN) == 0) {
+    // These notifications are used by tests to simulate a Places shutdown.
+    // They should just be forwarded to the Database handle.
+    mDB->Observe(aSubject, aTopic, aData);
+  }
+
+  else if (strcmp(aTopic, TOPIC_PREF_CHANGED) == 0) {
+    LoadPrefs();
+  }
+
+  else if (strcmp(aTopic, TOPIC_APP_LOCALES_CHANGED) == 0) {
+    mBundle = nullptr;
+  }
+
+  return NS_OK;
+}
+
+// Query stuff *****************************************************************
+
+// Helper class for QueryToSelectClause
+//
+// This class helps to build part of the WHERE clause.
+
+class ConditionBuilder {
+ public:
+  ConditionBuilder& Condition(const char* aStr) {
+    if (!mClause.IsEmpty()) mClause.AppendLiteral(" AND ");
+    Str(aStr);
+    return *this;
+  }
+
+  ConditionBuilder& Str(const char* aStr) {
+    mClause.Append(' ');
+    mClause.Append(aStr);
+    mClause.Append(' ');
+    return *this;
+  }
+
+  ConditionBuilder& Param(const char* aParam) {
+    mClause.Append(' ');
+    mClause.Append(aParam);
+    mClause.Append(' ');
+    return *this;
+  }
+
+  void GetClauseString(nsCString& aResult) { aResult = mClause; }
+
+ private:
+  nsCString mClause;
+};
+
+// nsNavHistory::QueryToSelectClause
+//
+//    THE BEHAVIOR SHOULD BE IN SYNC WITH BindQueryClauseParameters
+//
+//    I don't check return values from the query object getters because there's
+//    no way for those to fail.
+
+nsresult nsNavHistory::QueryToSelectClause(
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions, nsCString* aClause) {
+  bool hasIt;
+  // We don't use the value from options here - we post filter if that
+  // is set.
+  bool excludeQueries = false;
+
+  ConditionBuilder clause;
+
+  if ((NS_SUCCEEDED(aQuery->GetHasBeginTime(&hasIt)) && hasIt) ||
+      (NS_SUCCEEDED(aQuery->GetHasEndTime(&hasIt)) && hasIt)) {
+    clause.Condition(
+        "EXISTS (SELECT 1 FROM moz_historyvisits "
+        "WHERE place_id = h.id");
+    // begin time
+    if (NS_SUCCEEDED(aQuery->GetHasBeginTime(&hasIt)) && hasIt)
+      clause.Condition("visit_date >=").Param(":begin_time");
+    // end time
+    if (NS_SUCCEEDED(aQuery->GetHasEndTime(&hasIt)) && hasIt)
+      clause.Condition("visit_date <=").Param(":end_time");
+    clause.Str(" LIMIT 1)");
+  }
+
+  // search terms
+  int32_t searchBehavior = mozIPlacesAutoComplete::BEHAVIOR_HISTORY |
+                           mozIPlacesAutoComplete::BEHAVIOR_BOOKMARK;
+  if (!aQuery->SearchTerms().IsEmpty()) {
+    // Re-use the autocomplete_match function.  Setting the behavior to match
+    // history or typed history or bookmarks or open pages will match almost
+    // everything.
+    clause.Condition("AUTOCOMPLETE_MATCH(")
+        .Param(":search_string")
+        .Str(", h.url, page_title, tags, ")
+        .Str(nsPrintfCString("1, 1, 1, 1, %d, %d",
+                             mozIPlacesAutoComplete::MATCH_ANYWHERE_UNMODIFIED,
+                             searchBehavior)
+                 .get())
+        .Str(", NULL)");
+    // Serching by terms implicitly exclude queries.
+    excludeQueries = true;
+  }
+
+  // min and max visit count
+  if (aQuery->MinVisits() >= 0)
+    clause.Condition("h.visit_count >=").Param(":min_visits");
+
+  if (aQuery->MaxVisits() >= 0)
+    clause.Condition("h.visit_count <=").Param(":max_visits");
+
+  // domain
+  if (!aQuery->Domain().IsVoid()) {
+    bool domainIsHost = false;
+    aQuery->GetDomainIsHost(&domainIsHost);
+    if (domainIsHost)
+      clause.Condition("h.rev_host =").Param(":domain_lower");
+    else
+      // see domain setting in BindQueryClauseParameters for why we do this
+      clause.Condition("h.rev_host >=")
+          .Param(":domain_lower")
+          .Condition("h.rev_host <")
+          .Param(":domain_upper");
+  }
+
+  // URI
+  if (aQuery->Uri()) {
+    clause.Condition("h.url_hash = hash(")
+        .Param(":uri")
+        .Str(")")
+        .Condition("h.url =")
+        .Param(":uri");
+  }
+
+  // tags
+  const nsTArray<nsString>& tags = aQuery->Tags();
+  if (tags.Length() > 0) {
+    clause.Condition("h.id");
+    if (aQuery->TagsAreNot()) clause.Str("NOT");
+    clause
+        .Str(
+            "IN "
+            "(SELECT bms.fk "
+            "FROM moz_bookmarks bms "
+            "JOIN moz_bookmarks tags ON bms.parent = tags.id "
+            "WHERE tags.parent =")
+        .Param(":tags_folder")
+        .Str("AND lower(tags.title) IN (");
+    for (uint32_t i = 0; i < tags.Length(); ++i) {
+      nsPrintfCString param(":tag%d_", i);
+      clause.Param(param.get());
+      if (i < tags.Length() - 1) clause.Str(",");
+    }
+    clause.Str(")");
+    if (!aQuery->TagsAreNot()) {
+      clause.Str("GROUP BY bms.fk HAVING count(*) >=").Param(":tag_count");
+    }
+    clause.Str(")");
+  }
+
+  // transitions
+  const nsTArray<uint32_t>& transitions = aQuery->Transitions();
+  for (uint32_t i = 0; i < transitions.Length(); ++i) {
+    nsPrintfCString param(":transition%d_", i);
+    clause
+        .Condition(
+            "h.id IN (SELECT place_id FROM moz_historyvisits "
+            "WHERE visit_type = ")
+        .Param(param.get())
+        .Str(")");
+  }
+
+  // parents
+  const nsTArray<nsCString>& parents = aQuery->Parents();
+  if (parents.Length() > 0) {
+    aOptions->SetQueryType(nsNavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS);
+    clause.Condition(
+        "b.parent IN( "
+        "WITH RECURSIVE parents(id) AS ( "
+        "SELECT id FROM moz_bookmarks WHERE GUID IN (");
+
+    for (uint32_t i = 0; i < parents.Length(); ++i) {
+      nsPrintfCString param(":parentguid%d_", i);
+      clause.Param(param.get());
+      if (i < parents.Length() - 1) {
+        clause.Str(",");
+      }
+    }
+    clause.Str(
+        ") "
+        "UNION ALL "
+        "SELECT b2.id "
+        "FROM moz_bookmarks b2 "
+        "JOIN parents p ON b2.parent = p.id "
+        "WHERE b2.type = 2 "
+        ") "
+        "SELECT id FROM parents "
+        ")");
+  }
+
+  if (excludeQueries) {
+    // Serching by terms implicitly exclude queries and folder shortcuts.
+    clause.Condition(
+        "NOT h.url_hash BETWEEN hash('place', 'prefix_lo') AND "
+        "hash('place', 'prefix_hi')");
+  }
+
+  clause.GetClauseString(*aClause);
+  return NS_OK;
+}
+
+// nsNavHistory::BindQueryClauseParameters
+//
+//    THE BEHAVIOR SHOULD BE IN SYNC WITH QueryToSelectClause
+
+nsresult nsNavHistory::BindQueryClauseParameters(
+    mozIStorageBaseStatement* statement,
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions) {
+  nsresult rv;
+
+  bool hasIt;
+  // begin time
+  if (NS_SUCCEEDED(aQuery->GetHasBeginTime(&hasIt)) && hasIt) {
+    PRTime time =
+        NormalizeTime(aQuery->BeginTimeReference(), aQuery->BeginTime());
+    rv = statement->BindInt64ByName("begin_time"_ns, time);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // end time
+  if (NS_SUCCEEDED(aQuery->GetHasEndTime(&hasIt)) && hasIt) {
+    PRTime time = NormalizeTime(aQuery->EndTimeReference(), aQuery->EndTime());
+    rv = statement->BindInt64ByName("end_time"_ns, time);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // search terms
+  if (!aQuery->SearchTerms().IsEmpty()) {
+    rv = statement->BindStringByName("search_string"_ns, aQuery->SearchTerms());
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // min and max visit count
+  int32_t visits = aQuery->MinVisits();
+  if (visits >= 0) {
+    rv = statement->BindInt32ByName("min_visits"_ns, visits);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  visits = aQuery->MaxVisits();
+  if (visits >= 0) {
+    rv = statement->BindInt32ByName("max_visits"_ns, visits);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // domain (see GetReversedHostname for more info on reversed host names)
+  if (!aQuery->Domain().IsVoid()) {
+    nsString revDomain;
+    GetReversedHostname(NS_ConvertUTF8toUTF16(aQuery->Domain()), revDomain);
+
+    if (aQuery->DomainIsHost()) {
+      rv = statement->BindStringByName("domain_lower"_ns, revDomain);
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      // for "mozilla.org" do query >= "gro.allizom." AND < "gro.allizom/"
+      // which will get everything starting with "gro.allizom." while using the
+      // index (using SUBSTRING() causes indexes to be discarded).
+      NS_ASSERTION(revDomain[revDomain.Length() - 1] == '.',
+                   "Invalid rev. host");
+      rv = statement->BindStringByName("domain_lower"_ns, revDomain);
+      NS_ENSURE_SUCCESS(rv, rv);
+      revDomain.Truncate(revDomain.Length() - 1);
+      revDomain.Append(char16_t('/'));
+      rv = statement->BindStringByName("domain_upper"_ns, revDomain);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  // URI
+  if (aQuery->Uri()) {
+    rv = URIBinder::Bind(statement, "uri"_ns, aQuery->Uri());
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // tags
+  const nsTArray<nsString>& tags = aQuery->Tags();
+  if (tags.Length() > 0) {
+    for (uint32_t i = 0; i < tags.Length(); ++i) {
+      nsPrintfCString paramName("tag%d_", i);
+      nsString utf16Tag = tags[i];
+      ToLowerCase(utf16Tag);
+      NS_ConvertUTF16toUTF8 tag(utf16Tag);
+      rv = statement->BindUTF8StringByName(paramName, tag);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+    int64_t tagsFolder = GetTagsFolder();
+    rv = statement->BindInt64ByName("tags_folder"_ns, tagsFolder);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!aQuery->TagsAreNot()) {
+      rv = statement->BindInt32ByName("tag_count"_ns, tags.Length());
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  // transitions
+  const nsTArray<uint32_t>& transitions = aQuery->Transitions();
+  for (uint32_t i = 0; i < transitions.Length(); ++i) {
+    nsPrintfCString paramName("transition%d_", i);
+    rv = statement->BindInt64ByName(paramName, transitions[i]);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // parents
+  const nsTArray<nsCString>& parents = aQuery->Parents();
+  for (uint32_t i = 0; i < parents.Length(); ++i) {
+    nsPrintfCString paramName("parentguid%d_", i);
+    rv = statement->BindUTF8StringByName(paramName, parents[i]);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+// nsNavHistory::ResultsAsList
+//
+
+nsresult nsNavHistory::ResultsAsList(
+    mozIStorageStatement* statement, nsNavHistoryQueryOptions* aOptions,
+    nsCOMArray<nsNavHistoryResultNode>* aResults) {
+  nsresult rv;
+  nsCOMPtr<mozIStorageValueArray> row = do_QueryInterface(statement, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool hasMore = false;
+  while (NS_SUCCEEDED(statement->ExecuteStep(&hasMore)) && hasMore) {
+    RefPtr<nsNavHistoryResultNode> result;
+    rv = RowToResult(row, aOptions, getter_AddRefs(result));
+    NS_ENSURE_SUCCESS(rv, rv);
+    aResults->AppendElement(result.forget());
+  }
+  return NS_OK;
+}
+
+int64_t nsNavHistory::GetTagsFolder() {
+  // cache our tags folder
+  // note, we can't do this in nsNavHistory::Init(),
+  // as getting the bookmarks service would initialize it.
+  if (mTagsFolder == -1) {
+    nsNavBookmarks* bookmarks = nsNavBookmarks::GetBookmarksService();
+    NS_ENSURE_TRUE(bookmarks, -1);
+
+    nsresult rv = bookmarks->GetTagsFolder(&mTagsFolder);
+    NS_ENSURE_SUCCESS(rv, -1);
+  }
+  return mTagsFolder;
+}
+
+// nsNavHistory::FilterResultSet
+//
+// This does some post-query-execution filtering:
+//   - searching on title, url and tags
+//   - limit count
+//
+// Note:  changes to filtering in FilterResultSet()
+// may require changes to NeedToFilterResultSet()
+
+// static
+nsresult nsNavHistory::FilterResultSet(
+    nsNavHistoryQueryResultNode* aQueryNode,
+    const nsCOMArray<nsNavHistoryResultNode>& aSet,
+    nsCOMArray<nsNavHistoryResultNode>* aFiltered,
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    nsNavHistoryQueryOptions* aOptions) {
+  // parse the search terms
+  nsTArray<nsString> terms;
+  ParseSearchTermsFromQuery(aQuery, &terms);
+
+  bool excludeQueries = aOptions->ExcludeQueries();
+  for (int32_t nodeIndex = 0; nodeIndex < aSet.Count(); nodeIndex++) {
+    if (excludeQueries && aSet[nodeIndex]->IsQuery()) {
+      continue;
+    }
+
+    if (aSet[nodeIndex]->mItemId != -1 && aQueryNode &&
+        aQueryNode->mItemId == aSet[nodeIndex]->mItemId) {
+      continue;
+    }
+
+    // If there are search terms, we are already getting only uri nodes,
+    // thus we don't need to filter node types. Though, we must check for
+    // matching terms.
+    if (terms.Length()) {
+      // Filter based on search terms.
+      // Convert title and url for the current node to UTF16 strings.
+      NS_ConvertUTF8toUTF16 nodeTitle(aSet[nodeIndex]->mTitle);
+      // Unescape the URL for search terms matching.
+      nsAutoCString cNodeURL(aSet[nodeIndex]->mURI);
+      NS_ConvertUTF8toUTF16 nodeURL(NS_UnescapeURL(cNodeURL));
+
+      // Determine if every search term matches anywhere in the title, url or
+      // tag.
+      bool matchAllTerms = true;
+      for (int32_t termIndex = terms.Length() - 1;
+           termIndex >= 0 && matchAllTerms; termIndex--) {
+        nsString& term = terms.ElementAt(termIndex);
+        // True if any of them match; false makes us quit the loop
+        matchAllTerms =
+            CaseInsensitiveFindInReadable(term, nodeTitle) ||
+            CaseInsensitiveFindInReadable(term, nodeURL) ||
+            CaseInsensitiveFindInReadable(term, aSet[nodeIndex]->mTags);
+      }
+      // Skip the node if we don't match all terms in the title, url or tag
+      if (!matchAllTerms) {
+        continue;
+      }
+    }
+
+    aFiltered->AppendObject(aSet[nodeIndex]);
+
+    // Stop once we have reached max results.
+    if (aOptions->MaxResults() > 0 &&
+        (uint32_t)aFiltered->Count() >= aOptions->MaxResults())
+      break;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::MakeGuid(nsACString& aGuid) {
+  if (NS_FAILED(GenerateGUID(aGuid))) {
+    MOZ_ASSERT(false, "Shouldn't fail to create a guid!");
+    aGuid.SetIsVoid(true);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistory::HashURL(const nsACString& aSpec, const nsACString& aMode,
+                      uint64_t* _hash) {
+  return places::HashURL(aSpec, aMode, _hash);
+}
+
+// nsNavHistory::CheckIsRecentEvent
+//
+//    Sees if this URL happened "recently."
+//
+//    It is always removed from our recent list no matter what. It only counts
+//    as "recent" if the event happened more recently than our event
+//    threshold ago.
+
+bool nsNavHistory::CheckIsRecentEvent(RecentEventHash* hashTable,
+                                      const nsACString& url) {
+  PRTime eventTime;
+  if (hashTable->Get(url, reinterpret_cast<int64_t*>(&eventTime))) {
+    hashTable->Remove(url);
+    if (eventTime > GetNow() - RECENT_EVENT_THRESHOLD) return true;
+    return false;
+  }
+  return false;
+}
+
+// nsNavHistory::ExpireNonrecentEvents
+//
+//    This goes through our
+
+void nsNavHistory::ExpireNonrecentEvents(RecentEventHash* hashTable) {
+  int64_t threshold = GetNow() - RECENT_EVENT_THRESHOLD;
+  for (auto iter = hashTable->Iter(); !iter.Done(); iter.Next()) {
+    if (iter.Data() < threshold) {
+      iter.Remove();
+    }
+  }
+}
+
+// nsNavHistory::RowToResult
+//
+//    Here, we just have a generic row. It could be a query, URL, visit,
+//    or full visit.
+
+nsresult nsNavHistory::RowToResult(mozIStorageValueArray* aRow,
+                                   nsNavHistoryQueryOptions* aOptions,
+                                   nsNavHistoryResultNode** aResult) {
+  NS_ASSERTION(aRow && aOptions && aResult, "Null pointer in RowToResult");
+
+  // URL
+  nsAutoCString url;
+  nsresult rv = aRow->GetUTF8String(kGetInfoIndex_URL, url);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // In case of data corruption URL may be null, but our UI code prefers an
+  // empty string.
+  if (url.IsVoid()) {
+    MOZ_ASSERT(false, "Found a NULL url in moz_places");
+    url.SetIsVoid(false);
+  }
+
+  // title
+  nsAutoCString title;
+  bool isNull;
+  rv = aRow->GetIsNull(kGetInfoIndex_Title, &isNull);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isNull) {
+    rv = aRow->GetUTF8String(kGetInfoIndex_Title, title);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  uint32_t accessCount = aRow->AsInt32(kGetInfoIndex_VisitCount);
+  PRTime time = aRow->AsInt64(kGetInfoIndex_VisitDate);
+
+  // itemId
+  int64_t itemId = aRow->AsInt64(kGetInfoIndex_ItemId);
+  if (itemId == 0) {
+    // This is not a bookmark.  For non-bookmarks we use a -1 itemId value.
+    // Notice ids in sqlite tables start from 1, so itemId cannot ever be 0.
+    itemId = -1;
+  }
+
+  if (IsQueryURI(url)) {
+    // Special case "place:" URIs: turn them into containers.
+    nsAutoCString guid;
+    if (itemId != -1) {
+      rv = aRow->GetUTF8String(nsNavBookmarks::kGetChildrenIndex_Guid, guid);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    if (aOptions->ResultType() ==
+            nsNavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY ||
+        aOptions->ResultType() ==
+            nsNavHistoryQueryOptions::RESULTS_AS_LEFT_PANE_QUERY) {
+      rv = aRow->GetUTF8String(kGetInfoIndex_Guid, guid);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    int64_t targetFolderItemId = -1;
+    nsAutoCString targetFolderGuid;
+    nsAutoCString targetFolderTitle;
+    rv = aRow->GetIsNull(kGetTargetFolder_Guid, &isNull);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!isNull) {
+      targetFolderItemId = aRow->AsInt64(kGetTargetFolder_ItemId);
+      rv = aRow->GetUTF8String(kGetTargetFolder_Guid, targetFolderGuid);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = aRow->GetUTF8String(kGetTargetFolder_Title, targetFolderTitle);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    RefPtr<nsNavHistoryResultNode> resultNode;
+    rv = QueryUriToResult(url, itemId, guid, title, targetFolderItemId,
+                          targetFolderGuid, targetFolderTitle, accessCount,
+                          time, getter_AddRefs(resultNode));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (itemId != -1 || aOptions->ResultType() ==
+                            nsNavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT) {
+      // RESULTS_AS_TAGS_ROOT has date columns
+      resultNode->mDateAdded = aRow->AsInt64(kGetInfoIndex_ItemDateAdded);
+      resultNode->mLastModified = aRow->AsInt64(kGetInfoIndex_ItemLastModified);
+      if (resultNode->IsFolder()) {
+        // If it's a simple folder node (i.e. a shortcut to another folder),
+        // apply our options for it. However, if the parent type was tag query,
+        // we do not apply them, because it would not yield any results.
+        resultNode->GetAsContainer()->mOptions = aOptions;
+      }
+    }
+
+    resultNode.forget(aResult);
+    return rv;
+  } else if (aOptions->ResultType() ==
+             nsNavHistoryQueryOptions::RESULTS_AS_URI) {
+    RefPtr<nsNavHistoryResultNode> resultNode =
+        new nsNavHistoryResultNode(url, title, accessCount, time);
+
+    if (itemId != -1) {
+      resultNode->mItemId = itemId;
+      resultNode->mDateAdded = aRow->AsInt64(kGetInfoIndex_ItemDateAdded);
+      resultNode->mLastModified = aRow->AsInt64(kGetInfoIndex_ItemLastModified);
+
+      rv = aRow->GetUTF8String(nsNavBookmarks::kGetChildrenIndex_Guid,
+                               resultNode->mBookmarkGuid);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+
+    resultNode->mFrecency = aRow->AsInt32(kGetInfoIndex_Frecency);
+    resultNode->mHidden = !!aRow->AsInt32(kGetInfoIndex_Hidden);
+
+    nsAutoString tags;
+    rv = aRow->GetString(kGetInfoIndex_ItemTags, tags);
+    NS_ENSURE_SUCCESS(rv, rv);
+    resultNode->SetTags(tags);
+
+    rv = aRow->GetUTF8String(kGetInfoIndex_Guid, resultNode->mPageGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    resultNode.forget(aResult);
+    return NS_OK;
+  }
+
+  if (aOptions->ResultType() == nsNavHistoryQueryOptions::RESULTS_AS_VISIT) {
+    RefPtr<nsNavHistoryResultNode> resultNode =
+        new nsNavHistoryResultNode(url, title, accessCount, time);
+
+    nsAutoString tags;
+    rv = aRow->GetString(kGetInfoIndex_ItemTags, tags);
+    resultNode->SetTags(tags);
+    rv = aRow->GetUTF8String(kGetInfoIndex_Guid, resultNode->mPageGuid);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = aRow->GetInt64(kGetInfoIndex_VisitId, &resultNode->mVisitId);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    resultNode->mTransitionType = aRow->AsInt32(kGetInfoIndex_VisitType);
+
+    resultNode.forget(aResult);
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+// When the URI is a place: URI, generate the proper folder or query node.
+nsresult nsNavHistory::QueryUriToResult(
+    const nsACString& aQueryURI, int64_t aItemId,
+    const nsACString& aBookmarkGuid, const nsACString& aTitle,
+    int64_t aTargetFolderItemId, const nsACString& aTargetFolderGuid,
+    const nsACString& aTargetFolderTitle, uint32_t aAccessCount, PRTime aTime,
+    nsNavHistoryResultNode** aNode) {
+  // Only assert if the aItemId is set. In some cases (e.g. virtual queries), we
+  // have a guid, but not an aItemId.
+  if (aItemId != -1) {
+    MOZ_ASSERT(!aBookmarkGuid.IsEmpty());
+  }
+
+  nsCOMPtr<nsINavHistoryQuery> query;
+  nsCOMPtr<nsINavHistoryQueryOptions> options;
+  nsresult rv = QueryStringToQuery(aQueryURI, getter_AddRefs(query),
+                                   getter_AddRefs(options));
+  RefPtr<nsNavHistoryResultNode> resultNode;
+  RefPtr<nsNavHistoryQuery> queryObj = do_QueryObject(query);
+  NS_ENSURE_STATE(queryObj);
+  RefPtr<nsNavHistoryQueryOptions> optionsObj = do_QueryObject(options);
+  NS_ENSURE_STATE(optionsObj);
+  // If this failed the query does not parse correctly, let the error pass and
+  // handle it later.
+  if (NS_SUCCEEDED(rv)) {
+    if (!aTargetFolderGuid.IsEmpty()) {
+      MOZ_ASSERT(aTargetFolderItemId >= 0);
+      resultNode = new nsNavHistoryFolderResultNode(
+          aItemId, aBookmarkGuid, aTargetFolderItemId, aTargetFolderGuid,
+          !aTitle.IsEmpty() ? aTitle : aTargetFolderTitle, optionsObj);
+    } else {
+      // This is a regular query.
+      resultNode = new nsNavHistoryQueryResultNode(aTitle, aTime, aQueryURI,
+                                                   queryObj, optionsObj);
+      resultNode->mItemId = aItemId;
+      resultNode->mBookmarkGuid = aBookmarkGuid;
+    }
+  }
+
+  if (NS_FAILED(rv)) {
+    NS_WARNING("Generating a generic empty node for a broken query!");
+    // This is a broken query, that either did not parse or points to not
+    // existing data.  We don't want to return failure since that will kill the
+    // whole result.  Instead make a generic empty query node.
+    resultNode = new nsNavHistoryQueryResultNode(aTitle, 0, aQueryURI, queryObj,
+                                                 optionsObj);
+    resultNode->mItemId = aItemId;
+    resultNode->mBookmarkGuid = aBookmarkGuid;
+    // This is a perf hack to generate an empty query that skips filtering.
+    resultNode->GetAsQuery()->Options()->SetExcludeItems(true);
+  }
+
+  resultNode.forget(aNode);
+  return NS_OK;
+}
+
+void nsNavHistory::GetAgeInDaysString(int32_t aInt, const char* aName,
+                                      nsACString& aResult) {
+  nsIStringBundle* bundle = GetBundle();
+  if (bundle) {
+    AutoTArray<nsString, 1> strings;
+    strings.AppendElement()->AppendInt(aInt);
+    nsAutoString value;
+    nsresult rv = bundle->FormatStringFromName(aName, strings, value);
+    if (NS_SUCCEEDED(rv)) {
+      CopyUTF16toUTF8(value, aResult);
+      return;
+    }
+  }
+  aResult.Assign(aName);
+}
+
+void nsNavHistory::GetStringFromName(const char* aName, nsACString& aResult) {
+  nsIStringBundle* bundle = GetBundle();
+  if (bundle) {
+    nsAutoString value;
+    nsresult rv = bundle->GetStringFromName(aName, value);
+    if (NS_SUCCEEDED(rv)) {
+      CopyUTF16toUTF8(value, aResult);
+      return;
+    }
+  }
+  aResult.Assign(aName);
+}
+
+// static
+void nsNavHistory::GetMonthName(const PRExplodedTime& aTime,
+                                nsACString& aResult) {
+  nsAutoString month;
+
+  mozilla::intl::DateTimeFormat::ComponentsBag components;
+  components.month = Some(mozilla::intl::DateTimeFormat::Month::Long);
+  nsresult rv =
+      mozilla::intl::AppDateTimeFormat::Format(components, &aTime, month);
+  if (NS_FAILED(rv)) {
+    aResult = nsPrintfCString("[%d]", aTime.tm_month + 1);
+    return;
+  }
+  CopyUTF16toUTF8(month, aResult);
+}
+
+// static
+void nsNavHistory::GetMonthYear(const PRExplodedTime& aTime,
+                                nsACString& aResult) {
+  nsAutoString monthYear;
+  mozilla::intl::DateTimeFormat::ComponentsBag components;
+  components.month = Some(mozilla::intl::DateTimeFormat::Month::Long);
+  components.year = Some(mozilla::intl::DateTimeFormat::Numeric::Numeric);
+  nsresult rv =
+      mozilla::intl::AppDateTimeFormat::Format(components, &aTime, monthYear);
+  if (NS_FAILED(rv)) {
+    aResult = nsPrintfCString("[%d-%d]", aTime.tm_month + 1, aTime.tm_year);
+    return;
+  }
+  CopyUTF16toUTF8(monthYear, aResult);
+}
+
+namespace {
+
+// GetSimpleBookmarksQueryParent
+//
+//    Determines if this is a simple bookmarks query for a
+//    folder with no other constraints. In these common cases, we can more
+//    efficiently compute the results.
+//
+//    A simple bookmarks query will result in a hierarchical tree of
+//    bookmark items, folders and separators.
+//
+//    Returns the folder ID as Maybe<nsCString> if it is a simple folder
+//    query, Nothing() if not.
+static Maybe<nsCString> GetSimpleBookmarksQueryParent(
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions) {
+  if (aQuery->Parents().Length() != 1) return Nothing();
+
+  bool hasIt;
+  if ((NS_SUCCEEDED(aQuery->GetHasBeginTime(&hasIt)) && hasIt) ||
+      (NS_SUCCEEDED(aQuery->GetHasEndTime(&hasIt)) && hasIt) ||
+      !aQuery->Domain().IsVoid() || aQuery->Uri() ||
+      !aQuery->SearchTerms().IsEmpty() || aQuery->Tags().Length() > 0 ||
+      aOptions->MaxResults() > 0 || !IsValidGUID(aQuery->Parents()[0])) {
+    return Nothing();
+  }
+
+  return Some(aQuery->Parents()[0]);
+}
+
+// ParseSearchTermsFromQuery
+//
+//    Construct an array of search terms from the given query.
+//    Within a query, all the terms are ANDed together.
+//
+//    This just breaks the query up into words. We don't do anything fancy,
+//    not even quoting. We do, however, strip quotes, because people might
+//    try to input quotes expecting them to do something and get no results
+//    back.
+
+inline bool isQueryWhitespace(char16_t ch) { return ch == ' '; }
+
+void ParseSearchTermsFromQuery(const RefPtr<nsNavHistoryQuery>& aQuery,
+                               nsTArray<nsString>* aTerms) {
+  int32_t lastBegin = -1;
+  if (!aQuery->SearchTerms().IsEmpty()) {
+    const nsString& searchTerms = aQuery->SearchTerms();
+    for (uint32_t j = 0; j < searchTerms.Length(); j++) {
+      if (isQueryWhitespace(searchTerms[j]) || searchTerms[j] == '"') {
+        if (lastBegin >= 0) {
+          // found the end of a word
+          aTerms->AppendElement(
+              Substring(searchTerms, lastBegin, j - lastBegin));
+          lastBegin = -1;
+        }
+      } else {
+        if (lastBegin < 0) {
+          // found the beginning of a word
+          lastBegin = j;
+        }
+      }
+    }
+    // last word
+    if (lastBegin >= 0)
+      aTerms->AppendElement(Substring(searchTerms, lastBegin));
+  }
+}
+
+}  // namespace
+
+const mozilla::intl::Collator* nsNavHistory::GetCollator() {
+  if (mCollator) {
+    return mCollator.get();
+  }
+
+  auto result = mozilla::intl::LocaleService::TryCreateComponent<
+      mozilla::intl::Collator>();
+  NS_ENSURE_TRUE(result.isOk(), nullptr);
+  auto collator = result.unwrap();
+
+  // Sort in a case-insensitive way, where "base" letters are considered
+  // equal, e.g: a = á, a = A, a ≠ b.
+  using mozilla::intl::Collator;
+  Collator::Options options{};
+  options.sensitivity = Collator::Sensitivity::Base;
+  auto optResult = collator->SetOptions(options);
+  NS_ENSURE_TRUE(optResult.isOk(), nullptr);
+
+  mCollator = UniquePtr<const Collator>(collator.release());
+
+  return mCollator.get();
+}
+
+nsIStringBundle* nsNavHistory::GetBundle() {
+  if (!mBundle) {
+    nsCOMPtr<nsIStringBundleService> bundleService =
+        components::StringBundle::Service();
+    NS_ENSURE_TRUE(bundleService, nullptr);
+    nsresult rv = bundleService->CreateBundle(
+        "chrome://places/locale/places.properties", getter_AddRefs(mBundle));
+    NS_ENSURE_SUCCESS(rv, nullptr);
+  }
+  return mBundle;
+}
diff --git a/toolkit/components/places/nsNavHistory.h b/toolkit/components/places/nsNavHistory.h
new file mode 100644
index 0000000000..0ee33b8698
--- /dev/null
+++ b/toolkit/components/places/nsNavHistory.h
@@ -0,0 +1,475 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsNavHistory_h_
+#define nsNavHistory_h_
+
+#include "nsINavHistoryService.h"
+
+#include "nsIStringBundle.h"
+#include "nsITimer.h"
+#include "nsMaybeWeakPtr.h"
+#include "nsCategoryCache.h"
+#include "nsNetCID.h"
+#include "nsToolkitCompsCID.h"
+#include "nsURIHashKey.h"
+#include "nsTHashtable.h"
+
+#include "nsNavHistoryResult.h"
+#include "nsNavHistoryQuery.h"
+#include "Database.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/intl/Collator.h"
+#include "mozilla/UniquePtr.h"
+#include "mozIStorageVacuumParticipant.h"
+
+#define QUERYUPDATE_TIME 0
+#define QUERYUPDATE_SIMPLE 1
+#define QUERYUPDATE_COMPLEX 2
+#define QUERYUPDATE_COMPLEX_WITH_BOOKMARKS 3
+#define QUERYUPDATE_HOST 4
+#define QUERYUPDATE_MOBILEPREF 5
+#define QUERYUPDATE_NONE 6
+
+// Clamp title and URL to generously large, but not too large, length.
+// See bug 319004 for details.
+#define URI_LENGTH_MAX 65536
+#define TITLE_LENGTH_MAX 4096
+
+// Microsecond timeout for "recent" events such as typed and bookmark following.
+// If you typed it more than this time ago, it's not recent.
+#define RECENT_EVENT_THRESHOLD PRTime((int64_t)15 * 60 * PR_USEC_PER_SEC)
+
+// The preference we watch to know when the mobile bookmarks folder is filled by
+// sync.
+#define MOBILE_BOOKMARKS_PREF "browser.bookmarks.showMobileBookmarks"
+
+// The guid of the mobile bookmarks virtual query.
+#define MOBILE_BOOKMARKS_VIRTUAL_GUID "mobile_____v"
+
+#define ROOT_GUID "root________"
+#define MENU_ROOT_GUID "menu________"
+#define TOOLBAR_ROOT_GUID "toolbar_____"
+#define UNFILED_ROOT_GUID "unfiled_____"
+#define TAGS_ROOT_GUID "tags________"
+#define MOBILE_ROOT_GUID "mobile______"
+
+#define SQL_QUOTE(text) "'" text "'"
+
+class mozIStorageValueArray;
+class nsIAutoCompleteController;
+class nsIEffectiveTLDService;
+class nsIIDNService;
+class nsNavHistory;
+class PlacesSQLQueryBuilder;
+
+// nsNavHistory
+
+class nsNavHistory final : public nsSupportsWeakReference,
+                           public nsINavHistoryService,
+                           public nsIObserver,
+                           public mozIStorageVacuumParticipant {
+  friend class PlacesSQLQueryBuilder;
+
+ public:
+  nsNavHistory();
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSINAVHISTORYSERVICE
+  NS_DECL_NSIOBSERVER
+  NS_DECL_MOZISTORAGEVACUUMPARTICIPANT
+
+  /**
+   * Obtains the nsNavHistory object.
+   */
+  static already_AddRefed<nsNavHistory> GetSingleton();
+
+  /**
+   * Initializes the nsNavHistory object.  This should only be called once.
+   */
+  nsresult Init();
+
+  /**
+   * Used by other components in the places directory such as the annotation
+   * service to get a reference to this history object. Returns a pointer to
+   * the service if it exists. Otherwise creates one. Returns nullptr on error.
+   */
+  static nsNavHistory* GetHistoryService() {
+    if (!gHistoryService) {
+      nsCOMPtr<nsINavHistoryService> serv =
+          do_GetService(NS_NAVHISTORYSERVICE_CONTRACTID);
+      NS_ENSURE_TRUE(serv, nullptr);
+      NS_ASSERTION(gHistoryService, "Should have static instance pointer now");
+    }
+    return gHistoryService;
+  }
+
+  /**
+   * Used by other components in the places directory to get a reference to a
+   * const version of this history object.
+   *
+   * @return A pointer to a const version of the service if it exists,
+   *         nullptr otherwise.
+   */
+  static const nsNavHistory* GetConstHistoryService() {
+    const nsNavHistory* const history = gHistoryService;
+    return history;
+  }
+
+  /**
+   * Fetches the database id and the GUID associated to the given URI.
+   *
+   * @param aURI
+   *        The page to look for.
+   * @param _pageId
+   *        Will be set to the database id associated with the page.
+   *        If the page doesn't exist, this will be zero.
+   * @param _GUID
+   *        Will be set to the unique id associated with the page.
+   *        If the page doesn't exist, this will be empty.
+   * @note This DOES NOT check for bad URLs other than that they're nonempty.
+   */
+  nsresult GetIdForPage(nsIURI* aURI, int64_t* _pageId, nsCString& _GUID);
+
+  /**
+   * Fetches the database id and the GUID associated to the given URI, creating
+   * a new database entry if one doesn't exist yet.
+   *
+   * @param aURI
+   *        The page to look for or create.
+   * @param _pageId
+   *        Will be set to the database id associated with the page.
+   * @param _GUID
+   *        Will be set to the unique id associated with the page.
+   * @note This DOES NOT check for bad URLs other than that they're nonempty.
+   * @note This DOES NOT update frecency of the page.
+   */
+  nsresult GetOrCreateIdForPage(nsIURI* aURI, int64_t* _pageId,
+                                nsCString& _GUID);
+
+  /**
+   * These functions return non-owning references to the locale-specific
+   * objects for places components.
+   */
+  nsIStringBundle* GetBundle();
+  const mozilla::intl::Collator* GetCollator();
+  void GetStringFromName(const char* aName, nsACString& aResult);
+  void GetAgeInDaysString(int32_t aInt, const char* aName, nsACString& aResult);
+  static void GetMonthName(const PRExplodedTime& aTime, nsACString& aResult);
+  static void GetMonthYear(const PRExplodedTime& aTime, nsACString& aResult);
+
+  // Returns whether history is enabled or not.
+  bool IsHistoryDisabled() { return !mHistoryEnabled; }
+
+  // Returns whether or not diacritics must match in history text searches.
+  bool MatchDiacritics() const { return mMatchDiacritics; }
+
+  // Constants for the columns returned by the above statement.
+  static const int32_t kGetInfoIndex_PageID;
+  static const int32_t kGetInfoIndex_URL;
+  static const int32_t kGetInfoIndex_Title;
+  static const int32_t kGetInfoIndex_RevHost;
+  static const int32_t kGetInfoIndex_VisitCount;
+  static const int32_t kGetInfoIndex_VisitDate;
+  static const int32_t kGetInfoIndex_FaviconURL;
+  static const int32_t kGetInfoIndex_ItemId;
+  static const int32_t kGetInfoIndex_ItemDateAdded;
+  static const int32_t kGetInfoIndex_ItemLastModified;
+  static const int32_t kGetInfoIndex_ItemParentId;
+  static const int32_t kGetInfoIndex_ItemTags;
+  static const int32_t kGetInfoIndex_Frecency;
+  static const int32_t kGetInfoIndex_Hidden;
+  static const int32_t kGetInfoIndex_Guid;
+  static const int32_t kGetInfoIndex_VisitId;
+  static const int32_t kGetInfoIndex_FromVisitId;
+  static const int32_t kGetInfoIndex_VisitType;
+  static const int32_t kGetTargetFolder_Guid;
+  static const int32_t kGetTargetFolder_ItemId;
+  static const int32_t kGetTargetFolder_Title;
+
+  int64_t GetTagsFolder();
+
+  // this actually executes a query and gives you results, it is used by
+  // nsNavHistoryQueryResultNode
+  nsresult GetQueryResults(nsNavHistoryQueryResultNode* aResultNode,
+                           const RefPtr<nsNavHistoryQuery>& aQuery,
+                           const RefPtr<nsNavHistoryQueryOptions>& aOptions,
+                           nsCOMArray<nsNavHistoryResultNode>* aResults);
+
+  // Take a row of kGetInfoIndex_* columns and construct a ResultNode.
+  // The row must contain the full set of columns.
+  nsresult RowToResult(mozIStorageValueArray* aRow,
+                       nsNavHistoryQueryOptions* aOptions,
+                       nsNavHistoryResultNode** aResult);
+
+  nsresult QueryUriToResult(const nsACString& aQueryURI, int64_t aItemId,
+                            const nsACString& aBookmarkGuid,
+                            const nsACString& aTitle,
+                            int64_t aTargetFolderItemId,
+                            const nsACString& aTargetFolderGuid,
+                            const nsACString& aTargetFolderTitle,
+                            uint32_t aAccessCount, PRTime aTime,
+                            nsNavHistoryResultNode** aNode);
+
+  /**
+   * Returns current number of days stored in history.
+   */
+  int32_t GetDaysOfHistory();
+
+  void DomainNameFromURI(nsIURI* aURI, nsACString& aDomainName);
+  static PRTime NormalizeTime(uint32_t aRelative, PRTime aOffset);
+
+  typedef nsTHashMap<nsCStringHashKey, nsCString> StringHash;
+
+  enum RecentEventFlags {
+    RECENT_TYPED = 1 << 0,      // User typed in URL recently
+    RECENT_ACTIVATED = 1 << 1,  // User tapped URL link recently
+    RECENT_BOOKMARKED = 1 << 2  // User bookmarked URL recently
+  };
+
+  /**
+   * Returns any recent activity done with a URL.
+   * @return Any recent events associated with this URI.  Each bit is set
+   *         according to RecentEventFlags enum values.
+   */
+  uint32_t GetRecentFlags(nsIURI* aURI);
+
+  /**
+   * Whether there are visits.
+   * Note: This may cause synchronous I/O.
+   */
+  bool hasHistoryEntries();
+
+  /**
+   * Returns whether the specified url has a embed visit.
+   *
+   * @param aURI
+   *        URI of the page.
+   * @return whether the page has a embed visit.
+   */
+  bool hasEmbedVisit(nsIURI* aURI);
+
+  int32_t GetFrecencyAgedWeight(int32_t aAgeInDays) const {
+    if (aAgeInDays <= mFirstBucketCutoffInDays) {
+      return mFirstBucketWeight;
+    }
+    if (aAgeInDays <= mSecondBucketCutoffInDays) {
+      return mSecondBucketWeight;
+    }
+    if (aAgeInDays <= mThirdBucketCutoffInDays) {
+      return mThirdBucketWeight;
+    }
+    if (aAgeInDays <= mFourthBucketCutoffInDays) {
+      return mFourthBucketWeight;
+    }
+    return mDefaultWeight;
+  }
+
+  int32_t GetFrecencyTransitionBonus(int32_t aTransitionType, bool aVisited,
+                                     bool aRedirect = false) const {
+    if (aRedirect) {
+      return mRedirectSourceVisitBonus;
+    }
+
+    switch (aTransitionType) {
+      case nsINavHistoryService::TRANSITION_EMBED:
+        return mEmbedVisitBonus;
+      case nsINavHistoryService::TRANSITION_FRAMED_LINK:
+        return mFramedLinkVisitBonus;
+      case nsINavHistoryService::TRANSITION_LINK:
+        return mLinkVisitBonus;
+      case nsINavHistoryService::TRANSITION_TYPED:
+        return aVisited ? mTypedVisitBonus : mUnvisitedTypedBonus;
+      case nsINavHistoryService::TRANSITION_BOOKMARK:
+        return aVisited ? mBookmarkVisitBonus : mUnvisitedBookmarkBonus;
+      case nsINavHistoryService::TRANSITION_DOWNLOAD:
+        return mDownloadVisitBonus;
+      case nsINavHistoryService::TRANSITION_REDIRECT_PERMANENT:
+        return mPermRedirectVisitBonus;
+      case nsINavHistoryService::TRANSITION_REDIRECT_TEMPORARY:
+        return mTempRedirectVisitBonus;
+      case nsINavHistoryService::TRANSITION_RELOAD:
+        return mReloadVisitBonus;
+      default:
+        // 0 == undefined (see bug #375777 for details)
+        NS_WARNING_ASSERTION(!aTransitionType,
+                             "new transition but no bonus for frecency");
+        return mDefaultVisitBonus;
+    }
+  }
+
+  int32_t GetNumVisitsForFrecency() const { return mNumVisitsForFrecency; }
+
+  /**
+   * Updates and invalidates the mDaysOfHistory cache. Should be
+   * called whenever a visit is added.
+   */
+  void UpdateDaysOfHistory(PRTime visitTime);
+
+  /**
+   * Get a SQL fragment to pre-cache all the tagged bookmark into a `tagged`
+   * CTE.
+   */
+  static nsLiteralCString GetTagsSqlFragment(const uint16_t aQueryType,
+                                             bool aExcludeItems);
+
+  /**
+   * Get target folder guid from given query URI.
+   * If the folder guid is not found, returns Nonthing().
+   */
+  static mozilla::Maybe<nsCString> GetTargetFolderGuid(
+      const nsACString& aQueryURI);
+
+  /**
+   * Store last insterted id for a table.
+   */
+  static mozilla::Atomic<int64_t> sLastInsertedPlaceId;
+  static mozilla::Atomic<int64_t> sLastInsertedVisitId;
+
+  /**
+   * Tracks whether frecency is currently being decayed.
+   */
+  static mozilla::Atomic<bool> sIsFrecencyDecaying;
+  /**
+   * Tracks whether there's frecency to be recalculated.
+   */
+  static mozilla::Atomic<bool> sShouldStartFrecencyRecalculation;
+
+  static void StoreLastInsertedId(const nsACString& aTable,
+                                  const int64_t aLastInsertedId);
+
+  static nsresult FilterResultSet(
+      nsNavHistoryQueryResultNode* aParentNode,
+      const nsCOMArray<nsNavHistoryResultNode>& aSet,
+      nsCOMArray<nsNavHistoryResultNode>* aFiltered,
+      const RefPtr<nsNavHistoryQuery>& aQuery,
+      nsNavHistoryQueryOptions* aOptions);
+
+  static void InvalidateDaysOfHistory();
+
+  static nsresult TokensToQuery(
+      const nsTArray<mozilla::places::QueryKeyValuePair>& aTokens,
+      nsNavHistoryQuery* aQuery, nsNavHistoryQueryOptions* aOptions);
+
+ private:
+  ~nsNavHistory();
+
+  // used by GetHistoryService
+  static nsNavHistory* gHistoryService;
+
+  static mozilla::Atomic<int32_t> sDaysOfHistory;
+
+ protected:
+  // Database handle.
+  RefPtr<mozilla::places::Database> mDB;
+
+  /**
+   * Loads all of the preferences that we use into member variables.
+   *
+   * @note If mPrefBranch is nullptr, this does nothing.
+   */
+  void LoadPrefs();
+
+  /**
+   * Calculates and returns value for mCachedNow.
+   * This is an hack to avoid calling PR_Now() too often, as is the case when
+   * we're asked the ageindays of many history entries in a row.  A timer is
+   * set which will clear our valid flag after a short timeout.
+   */
+  PRTime GetNow();
+  PRTime mCachedNow;
+  nsCOMPtr<nsITimer> mExpireNowTimer;
+  /**
+   * Called when the cached now value is expired and needs renewal.
+   */
+  static void expireNowTimerCallback(nsITimer* aTimer, void* aClosure);
+
+  nsresult ConstructQueryString(
+      const RefPtr<nsNavHistoryQuery>& aQuery,
+      const RefPtr<nsNavHistoryQueryOptions>& aOptions, nsCString& queryString,
+      bool& aParamsPresent, StringHash& aAddParams);
+
+  nsresult QueryToSelectClause(const RefPtr<nsNavHistoryQuery>& aQuery,
+                               const RefPtr<nsNavHistoryQueryOptions>& aOptions,
+                               nsCString* aClause);
+  nsresult BindQueryClauseParameters(
+      mozIStorageBaseStatement* statement,
+      const RefPtr<nsNavHistoryQuery>& aQuery,
+      const RefPtr<nsNavHistoryQueryOptions>& aOptions);
+
+  nsresult ResultsAsList(mozIStorageStatement* statement,
+                         nsNavHistoryQueryOptions* aOptions,
+                         nsCOMArray<nsNavHistoryResultNode>* aResults);
+
+  // effective tld service
+  nsCOMPtr<nsIEffectiveTLDService> mTLDService;
+  nsCOMPtr<nsIIDNService> mIDNService;
+
+  // localization
+  nsCOMPtr<nsIStringBundle> mBundle;
+  mozilla::UniquePtr<const mozilla::intl::Collator> mCollator;
+
+  // recent events
+  typedef nsTHashMap<nsCStringHashKey, int64_t> RecentEventHash;
+  RecentEventHash mRecentTyped;
+  RecentEventHash mRecentLink;
+  RecentEventHash mRecentBookmark;
+
+  bool CheckIsRecentEvent(RecentEventHash* hashTable, const nsACString& url);
+  void ExpireNonrecentEvents(RecentEventHash* hashTable);
+
+  // Whether history is enabled or not.
+  // Will mimic value of the places.history.enabled preference.
+  bool mHistoryEnabled;
+
+  // Whether or not diacritics must match in history text searches.
+  // Will mimic value of the places.search.matchDiacritics preference.
+  bool mMatchDiacritics;
+
+  // Frecency preferences.
+  int32_t mNumVisitsForFrecency;
+  int32_t mFirstBucketCutoffInDays;
+  int32_t mSecondBucketCutoffInDays;
+  int32_t mThirdBucketCutoffInDays;
+  int32_t mFourthBucketCutoffInDays;
+  int32_t mFirstBucketWeight;
+  int32_t mSecondBucketWeight;
+  int32_t mThirdBucketWeight;
+  int32_t mFourthBucketWeight;
+  int32_t mDefaultWeight;
+  int32_t mEmbedVisitBonus;
+  int32_t mFramedLinkVisitBonus;
+  int32_t mLinkVisitBonus;
+  int32_t mTypedVisitBonus;
+  int32_t mBookmarkVisitBonus;
+  int32_t mDownloadVisitBonus;
+  int32_t mPermRedirectVisitBonus;
+  int32_t mTempRedirectVisitBonus;
+  int32_t mRedirectSourceVisitBonus;
+  int32_t mDefaultVisitBonus;
+  int32_t mUnvisitedBookmarkBonus;
+  int32_t mUnvisitedTypedBonus;
+  int32_t mReloadVisitBonus;
+
+  int64_t mTagsFolder;
+  int64_t mLastCachedStartOfDay;
+  int64_t mLastCachedEndOfDay;
+};
+
+#define PLACES_URI_PREFIX "place:"
+
+/* Returns true if the given URI represents a history query. */
+inline static bool IsQueryURI(const nsACString& uri) {
+  return StringBeginsWith(uri, nsLiteralCString(PLACES_URI_PREFIX));
+}
+
+/* Extracts the query string from a query URI. */
+inline const nsDependentCSubstring QueryURIToQuery(const nsCString& uri) {
+  NS_ASSERTION(IsQueryURI(uri), "should only be called for query URIs");
+  return Substring(uri, nsLiteralCString(PLACES_URI_PREFIX).Length());
+}
+
+#endif  // nsNavHistory_h_
diff --git a/toolkit/components/places/nsNavHistoryQuery.cpp b/toolkit/components/places/nsNavHistoryQuery.cpp
new file mode 100644
index 0000000000..0b073548a8
--- /dev/null
+++ b/toolkit/components/places/nsNavHistoryQuery.cpp
@@ -0,0 +1,1180 @@
+//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file contains the definitions of nsNavHistoryQuery,
+ * nsNavHistoryQueryOptions, and those functions in nsINavHistory that directly
+ * support queries (specifically QueryStringToQuery and QueryToQueryString).
+ */
+
+#include "mozilla/DebugOnly.h"
+
+#include "nsNavHistory.h"
+#include "nsNavBookmarks.h"
+#include "nsEscape.h"
+#include "nsCOMArray.h"
+#include "nsNetUtil.h"
+#include "nsTArray.h"
+#include "nsQueryObject.h"
+#include "prprf.h"
+#include "nsVariant.h"
+
+using namespace mozilla;
+using namespace mozilla::places;
+
+static nsresult ParseQueryBooleanString(const nsCString& aString, bool* aValue);
+
+// query getters
+using BoolQueryGetter = nsresult (NS_STDCALL nsINavHistoryQuery::*)(bool*);
+using Uint32QueryGetter =
+    nsresult (NS_STDCALL nsINavHistoryQuery::*)(uint32_t*);
+using Int64QueryGetter = nsresult (NS_STDCALL nsINavHistoryQuery::*)(int64_t*);
+static void AppendBoolKeyValueIfTrue(nsACString& aString,
+                                     const nsCString& aName,
+                                     nsINavHistoryQuery* aQuery,
+                                     BoolQueryGetter getter);
+static void AppendUint32KeyValueIfNonzero(nsACString& aString,
+                                          const nsCString& aName,
+                                          nsINavHistoryQuery* aQuery,
+                                          Uint32QueryGetter getter);
+static void AppendInt64KeyValueIfNonzero(nsACString& aString,
+                                         const nsCString& aName,
+                                         nsINavHistoryQuery* aQuery,
+                                         Int64QueryGetter getter);
+
+// query setters
+using BoolQuerySetter = nsresult (NS_STDCALL nsINavHistoryQuery::*)(bool);
+using Uint32QuerySetter = nsresult (NS_STDCALL nsINavHistoryQuery::*)(uint32_t);
+using Int64QuerySetter = nsresult (NS_STDCALL nsINavHistoryQuery::*)(int64_t);
+static void SetQueryKeyBool(const nsCString& aValue, nsINavHistoryQuery* aQuery,
+                            BoolQuerySetter setter);
+static void SetQueryKeyUint32(const nsCString& aValue,
+                              nsINavHistoryQuery* aQuery,
+                              Uint32QuerySetter setter);
+static void SetQueryKeyInt64(const nsCString& aValue,
+                             nsINavHistoryQuery* aQuery,
+                             Int64QuerySetter setter);
+
+// options setters
+using BoolOptionsSetter =
+    nsresult (NS_STDCALL nsINavHistoryQueryOptions::*)(bool);
+using Uint32OptionsSetter =
+    nsresult (NS_STDCALL nsINavHistoryQueryOptions::*)(uint32_t);
+using Uint16OptionsSetter =
+    nsresult (NS_STDCALL nsINavHistoryQueryOptions::*)(uint16_t);
+static void SetOptionsKeyBool(const nsCString& aValue,
+                              nsINavHistoryQueryOptions* aOptions,
+                              BoolOptionsSetter setter);
+static void SetOptionsKeyUint16(const nsCString& aValue,
+                                nsINavHistoryQueryOptions* aOptions,
+                                Uint16OptionsSetter setter);
+static void SetOptionsKeyUint32(const nsCString& aValue,
+                                nsINavHistoryQueryOptions* aOptions,
+                                Uint32OptionsSetter setter);
+
+// Components of a query string.
+// Note that query strings are also generated in nsNavBookmarks::GetFolderURI
+// for performance reasons, so if you change these values, change that, too.
+#define QUERYKEY_BEGIN_TIME "beginTime"
+#define QUERYKEY_BEGIN_TIME_REFERENCE "beginTimeRef"
+#define QUERYKEY_END_TIME "endTime"
+#define QUERYKEY_END_TIME_REFERENCE "endTimeRef"
+#define QUERYKEY_SEARCH_TERMS "terms"
+#define QUERYKEY_MIN_VISITS "minVisits"
+#define QUERYKEY_MAX_VISITS "maxVisits"
+#define QUERYKEY_DOMAIN_IS_HOST "domainIsHost"
+#define QUERYKEY_DOMAIN "domain"
+#define QUERYKEY_PARENT "parent"
+#define QUERYKEY_URI "uri"
+#define QUERYKEY_GROUP "group"
+#define QUERYKEY_SORT "sort"
+#define QUERYKEY_RESULT_TYPE "type"
+#define QUERYKEY_EXCLUDE_ITEMS "excludeItems"
+#define QUERYKEY_EXCLUDE_QUERIES "excludeQueries"
+#define QUERYKEY_EXPAND_QUERIES "expandQueries"
+#define QUERYKEY_FORCE_ORIGINAL_TITLE "originalTitle"
+#define QUERYKEY_INCLUDE_HIDDEN "includeHidden"
+#define QUERYKEY_MAX_RESULTS "maxResults"
+#define QUERYKEY_QUERY_TYPE "queryType"
+#define QUERYKEY_TAG "tag"
+#define QUERYKEY_NOTTAGS "!tags"
+#define QUERYKEY_ASYNC_ENABLED "asyncEnabled"
+#define QUERYKEY_TRANSITION "transition"
+
+inline void AppendAmpersandIfNonempty(nsACString& aString) {
+  if (!aString.IsEmpty()) aString.Append('&');
+}
+inline void AppendInt16(nsACString& str, int16_t i) {
+  nsAutoCString tmp;
+  tmp.AppendInt(i);
+  str.Append(tmp);
+}
+inline void AppendInt32(nsACString& str, int32_t i) {
+  nsAutoCString tmp;
+  tmp.AppendInt(i);
+  str.Append(tmp);
+}
+inline void AppendInt64(nsACString& str, int64_t i) {
+  nsCString tmp;
+  tmp.AppendInt(i);
+  str.Append(tmp);
+}
+
+NS_IMETHODIMP
+nsNavHistory::QueryStringToQuery(const nsACString& aQueryString,
+                                 nsINavHistoryQuery** _query,
+                                 nsINavHistoryQueryOptions** _options) {
+  return nsNavHistoryQuery::QueryStringToQuery(aQueryString, _query, _options);
+}
+
+NS_IMETHODIMP
+nsNavHistory::QueryToQueryString(nsINavHistoryQuery* aQuery,
+                                 nsINavHistoryQueryOptions* aOptions,
+                                 nsACString& aQueryString) {
+  NS_ENSURE_ARG(aQuery);
+  NS_ENSURE_ARG(aOptions);
+
+  RefPtr<nsNavHistoryQuery> query = do_QueryObject(aQuery);
+  NS_ENSURE_STATE(query);
+  RefPtr<nsNavHistoryQueryOptions> options = do_QueryObject(aOptions);
+  NS_ENSURE_STATE(options);
+
+  nsAutoCString queryString;
+  bool hasIt;
+
+  // begin time
+  query->GetHasBeginTime(&hasIt);
+  if (hasIt) {
+    AppendInt64KeyValueIfNonzero(queryString,
+                                 nsLiteralCString(QUERYKEY_BEGIN_TIME), query,
+                                 &nsINavHistoryQuery::GetBeginTime);
+    AppendUint32KeyValueIfNonzero(
+        queryString, nsLiteralCString(QUERYKEY_BEGIN_TIME_REFERENCE), query,
+        &nsINavHistoryQuery::GetBeginTimeReference);
+  }
+
+  // end time
+  query->GetHasEndTime(&hasIt);
+  if (hasIt) {
+    AppendInt64KeyValueIfNonzero(queryString,
+                                 nsLiteralCString(QUERYKEY_END_TIME), query,
+                                 &nsINavHistoryQuery::GetEndTime);
+    AppendUint32KeyValueIfNonzero(
+        queryString, nsLiteralCString(QUERYKEY_END_TIME_REFERENCE), query,
+        &nsINavHistoryQuery::GetEndTimeReference);
+  }
+
+  // search terms
+  if (!query->SearchTerms().IsEmpty()) {
+    const nsString& searchTerms = query->SearchTerms();
+    nsCString escapedTerms;
+    if (!NS_Escape(NS_ConvertUTF16toUTF8(searchTerms), escapedTerms,
+                   url_XAlphas)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_SEARCH_TERMS "=");
+    queryString += escapedTerms;
+  }
+
+  // min and max visits
+  int32_t minVisits;
+  if (NS_SUCCEEDED(query->GetMinVisits(&minVisits)) && minVisits >= 0) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString.AppendLiteral(QUERYKEY_MIN_VISITS "=");
+    AppendInt32(queryString, minVisits);
+  }
+
+  int32_t maxVisits;
+  if (NS_SUCCEEDED(query->GetMaxVisits(&maxVisits)) && maxVisits >= 0) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString.AppendLiteral(QUERYKEY_MAX_VISITS "=");
+    AppendInt32(queryString, maxVisits);
+  }
+
+  // domain (+ is host), only call if hasDomain, which means non-IsVoid
+  // this means we may get an empty string for the domain in the result,
+  // which is valid
+  if (!query->Domain().IsVoid()) {
+    AppendBoolKeyValueIfTrue(queryString,
+                             nsLiteralCString(QUERYKEY_DOMAIN_IS_HOST), query,
+                             &nsINavHistoryQuery::GetDomainIsHost);
+    const nsCString& domain = query->Domain();
+    nsCString escapedDomain;
+    bool success = NS_Escape(domain, escapedDomain, url_XAlphas);
+    NS_ENSURE_TRUE(success, NS_ERROR_OUT_OF_MEMORY);
+
+    AppendAmpersandIfNonempty(queryString);
+    queryString.AppendLiteral(QUERYKEY_DOMAIN "=");
+    queryString.Append(escapedDomain);
+  }
+
+  // uri
+  if (query->Uri()) {
+    nsCOMPtr<nsIURI> uri = query->Uri();
+    nsAutoCString uriSpec;
+    nsresult rv = uri->GetSpec(uriSpec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    nsAutoCString escaped;
+    bool success = NS_Escape(uriSpec, escaped, url_XAlphas);
+    NS_ENSURE_TRUE(success, NS_ERROR_OUT_OF_MEMORY);
+
+    AppendAmpersandIfNonempty(queryString);
+    queryString.AppendLiteral(QUERYKEY_URI "=");
+    queryString.Append(escaped);
+  }
+
+  // parents
+  const nsTArray<nsCString>& parents = query->Parents();
+  for (uint32_t i = 0; i < parents.Length(); ++i) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_PARENT "=");
+    queryString += parents[i];
+  }
+
+  // tags
+  const nsTArray<nsString>& tags = query->Tags();
+  for (uint32_t i = 0; i < tags.Length(); ++i) {
+    nsAutoCString escapedTag;
+    if (!NS_Escape(NS_ConvertUTF16toUTF8(tags[i]), escapedTag, url_XAlphas)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_TAG "=");
+    queryString += escapedTag;
+  }
+  AppendBoolKeyValueIfTrue(queryString, nsLiteralCString(QUERYKEY_NOTTAGS),
+                           query, &nsINavHistoryQuery::GetTagsAreNot);
+
+  // transitions
+  const nsTArray<uint32_t>& transitions = query->Transitions();
+  for (uint32_t i = 0; i < transitions.Length(); ++i) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_TRANSITION "=");
+    AppendInt64(queryString, transitions[i]);
+  }
+
+  // sorting
+  if (options->SortingMode() != nsINavHistoryQueryOptions::SORT_BY_NONE) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_SORT "=");
+    AppendInt16(queryString, static_cast<int16_t>(options->SortingMode()));
+  }
+
+  // result type
+  if (options->ResultType() != nsINavHistoryQueryOptions::RESULTS_AS_URI) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_RESULT_TYPE "=");
+    AppendInt16(queryString, static_cast<int16_t>(options->ResultType()));
+  }
+
+  // exclude items
+  if (options->ExcludeItems()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_EXCLUDE_ITEMS "=1");
+  }
+
+  // exclude queries
+  if (options->ExcludeQueries()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_EXCLUDE_QUERIES "=1");
+  }
+
+  // expand queries
+  if (!options->ExpandQueries()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_EXPAND_QUERIES "=0");
+  }
+
+  // include hidden
+  if (options->IncludeHidden()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_INCLUDE_HIDDEN "=1");
+  }
+
+  // max results
+  if (options->MaxResults()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_MAX_RESULTS "=");
+    AppendInt32(queryString, static_cast<int32_t>(options->MaxResults()));
+  }
+
+  // queryType
+  if (options->QueryType() != nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_QUERY_TYPE "=");
+    AppendInt16(queryString, static_cast<int16_t>(options->QueryType()));
+  }
+
+  // async enabled
+  if (options->AsyncEnabled()) {
+    AppendAmpersandIfNonempty(queryString);
+    queryString += nsLiteralCString(QUERYKEY_ASYNC_ENABLED "=1");
+  }
+
+  aQueryString.AssignLiteral("place:");
+  aQueryString.Append(queryString);
+  return NS_OK;
+}
+
+/* static */
+nsresult nsNavHistory::TokensToQuery(const nsTArray<QueryKeyValuePair>& aTokens,
+                                     nsNavHistoryQuery* aQuery,
+                                     nsNavHistoryQueryOptions* aOptions) {
+  nsresult rv;
+
+  if (aTokens.Length() == 0) return NS_OK;
+
+  nsTArray<nsCString> parents;
+  nsTArray<nsString> tags;
+  nsTArray<uint32_t> transitions;
+  for (uint32_t i = 0; i < aTokens.Length(); i++) {
+    const QueryKeyValuePair& kvp = aTokens[i];
+
+    // begin time
+    if (kvp.key.EqualsLiteral(QUERYKEY_BEGIN_TIME)) {
+      SetQueryKeyInt64(kvp.value, aQuery, &nsINavHistoryQuery::SetBeginTime);
+
+      // begin time reference
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_BEGIN_TIME_REFERENCE)) {
+      SetQueryKeyUint32(kvp.value, aQuery,
+                        &nsINavHistoryQuery::SetBeginTimeReference);
+
+      // end time
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_END_TIME)) {
+      SetQueryKeyInt64(kvp.value, aQuery, &nsINavHistoryQuery::SetEndTime);
+
+      // end time reference
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_END_TIME_REFERENCE)) {
+      SetQueryKeyUint32(kvp.value, aQuery,
+                        &nsINavHistoryQuery::SetEndTimeReference);
+
+      // search terms
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_SEARCH_TERMS)) {
+      nsCString unescapedTerms = kvp.value;
+      NS_UnescapeURL(unescapedTerms);  // modifies input
+      rv = aQuery->SetSearchTerms(NS_ConvertUTF8toUTF16(unescapedTerms));
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // min visits
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_MIN_VISITS)) {
+      int32_t visits = kvp.value.ToInteger(&rv);
+      if (NS_SUCCEEDED(rv)) {
+        aQuery->SetMinVisits(visits);
+      } else {
+        NS_WARNING("Bad number for minVisits in query");
+      }
+
+      // max visits
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_MAX_VISITS)) {
+      int32_t visits = kvp.value.ToInteger(&rv);
+      if (NS_SUCCEEDED(rv)) {
+        aQuery->SetMaxVisits(visits);
+      } else {
+        NS_WARNING("Bad number for maxVisits in query");
+      }
+
+      // domainIsHost flag
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_DOMAIN_IS_HOST)) {
+      SetQueryKeyBool(kvp.value, aQuery, &nsINavHistoryQuery::SetDomainIsHost);
+
+      // domain string
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_DOMAIN)) {
+      nsAutoCString unescapedDomain(kvp.value);
+      NS_UnescapeURL(unescapedDomain);  // modifies input
+      rv = aQuery->SetDomain(unescapedDomain);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // parent folders (guids)
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_PARENT)) {
+      parents.AppendElement(kvp.value);
+
+      // uri
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_URI)) {
+      nsAutoCString unescapedUri(kvp.value);
+      NS_UnescapeURL(unescapedUri);  // modifies input
+      nsCOMPtr<nsIURI> uri;
+      nsresult rv = NS_NewURI(getter_AddRefs(uri), unescapedUri);
+      if (NS_FAILED(rv)) {
+        NS_WARNING("Unable to parse URI");
+      }
+      rv = aQuery->SetUri(uri);
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      // tag
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_TAG)) {
+      nsAutoCString unescaped(kvp.value);
+      NS_UnescapeURL(unescaped);  // modifies input
+      NS_ConvertUTF8toUTF16 tag(unescaped);
+      if (!tags.Contains(tag)) {
+        tags.AppendElement(tag);
+      }
+
+      // not tags
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_NOTTAGS)) {
+      SetQueryKeyBool(kvp.value, aQuery, &nsINavHistoryQuery::SetTagsAreNot);
+
+      // transition
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_TRANSITION)) {
+      uint32_t transition = kvp.value.ToInteger(&rv);
+      if (NS_SUCCEEDED(rv)) {
+        if (!transitions.Contains(transition)) {
+          transitions.AppendElement(transition);
+        }
+      } else {
+        NS_WARNING("Invalid Int32 transition value.");
+      }
+
+      // sorting mode
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_SORT)) {
+      SetOptionsKeyUint16(kvp.value, aOptions,
+                          &nsINavHistoryQueryOptions::SetSortingMode);
+      // result type
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_RESULT_TYPE)) {
+      SetOptionsKeyUint16(kvp.value, aOptions,
+                          &nsINavHistoryQueryOptions::SetResultType);
+
+      // exclude items
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_EXCLUDE_ITEMS)) {
+      SetOptionsKeyBool(kvp.value, aOptions,
+                        &nsINavHistoryQueryOptions::SetExcludeItems);
+
+      // exclude queries
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_EXCLUDE_QUERIES)) {
+      SetOptionsKeyBool(kvp.value, aOptions,
+                        &nsINavHistoryQueryOptions::SetExcludeQueries);
+
+      // expand queries
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_EXPAND_QUERIES)) {
+      SetOptionsKeyBool(kvp.value, aOptions,
+                        &nsINavHistoryQueryOptions::SetExpandQueries);
+      // include hidden
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_INCLUDE_HIDDEN)) {
+      SetOptionsKeyBool(kvp.value, aOptions,
+                        &nsINavHistoryQueryOptions::SetIncludeHidden);
+      // max results
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_MAX_RESULTS)) {
+      SetOptionsKeyUint32(kvp.value, aOptions,
+                          &nsINavHistoryQueryOptions::SetMaxResults);
+      // query type
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_QUERY_TYPE)) {
+      SetOptionsKeyUint16(kvp.value, aOptions,
+                          &nsINavHistoryQueryOptions::SetQueryType);
+      // async enabled
+    } else if (kvp.key.EqualsLiteral(QUERYKEY_ASYNC_ENABLED)) {
+      SetOptionsKeyBool(kvp.value, aOptions,
+                        &nsINavHistoryQueryOptions::SetAsyncEnabled);
+      // unknown key
+    } else {
+      NS_WARNING("TokensToQueries(), ignoring unknown key: ");
+      NS_WARNING(kvp.key.get());
+    }
+  }
+
+  if (parents.Length() != 0) {
+    rv = aQuery->SetParents(parents);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (tags.Length() > 0) {
+    aQuery->SetTags(std::move(tags));
+  }
+
+  if (transitions.Length() > 0) {
+    rv = aQuery->SetTransitions(transitions);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+// ParseQueryBooleanString
+//
+//    Converts a 0/1 or true/false string into a bool
+
+nsresult ParseQueryBooleanString(const nsCString& aString, bool* aValue) {
+  if (aString.EqualsLiteral("1") || aString.EqualsLiteral("true")) {
+    *aValue = true;
+    return NS_OK;
+  }
+  if (aString.EqualsLiteral("0") || aString.EqualsLiteral("false")) {
+    *aValue = false;
+    return NS_OK;
+  }
+  return NS_ERROR_INVALID_ARG;
+}
+
+// nsINavHistoryQuery **********************************************************
+
+NS_IMPL_ISUPPORTS(nsNavHistoryQuery, nsNavHistoryQuery, nsINavHistoryQuery)
+
+// nsINavHistoryQuery::nsNavHistoryQuery
+//
+//    This must initialize the object such that the default values will cause
+//    all history to be returned if this query is used. Then the caller can
+//    just set the things it's interested in.
+
+nsNavHistoryQuery::nsNavHistoryQuery()
+    : mMinVisits(-1),
+      mMaxVisits(-1),
+      mBeginTime(0),
+      mBeginTimeReference(TIME_RELATIVE_EPOCH),
+      mEndTime(0),
+      mEndTimeReference(TIME_RELATIVE_EPOCH),
+      mDomainIsHost(false),
+      mTagsAreNot(false) {
+  // differentiate not set (IsVoid) from empty string (local files)
+  mDomain.SetIsVoid(true);
+}
+
+nsNavHistoryQuery::nsNavHistoryQuery(const nsNavHistoryQuery& aOther)
+    : mMinVisits(aOther.mMinVisits),
+      mMaxVisits(aOther.mMaxVisits),
+      mBeginTime(aOther.mBeginTime),
+      mBeginTimeReference(aOther.mBeginTimeReference),
+      mEndTime(aOther.mEndTime),
+      mEndTimeReference(aOther.mEndTimeReference),
+      mSearchTerms(aOther.mSearchTerms),
+      mDomainIsHost(aOther.mDomainIsHost),
+      mDomain(aOther.mDomain),
+      mUri(aOther.mUri),
+      mParents(aOther.mParents.Clone()),
+      mTags(aOther.mTags.Clone()),
+      mTagsAreNot(aOther.mTagsAreNot),
+      mTransitions(aOther.mTransitions.Clone()) {}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetBeginTime(PRTime* aBeginTime) {
+  *aBeginTime = mBeginTime;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetBeginTime(PRTime aBeginTime) {
+  mBeginTime = aBeginTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetBeginTimeReference(uint32_t* _retval) {
+  *_retval = mBeginTimeReference;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetBeginTimeReference(uint32_t aReference) {
+  if (aReference > TIME_RELATIVE_NOW) return NS_ERROR_INVALID_ARG;
+  mBeginTimeReference = aReference;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetHasBeginTime(bool* _retval) {
+  *_retval = !(mBeginTimeReference == TIME_RELATIVE_EPOCH && mBeginTime == 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetAbsoluteBeginTime(PRTime* _retval) {
+  *_retval = nsNavHistory::NormalizeTime(mBeginTimeReference, mBeginTime);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetEndTime(PRTime* aEndTime) {
+  *aEndTime = mEndTime;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetEndTime(PRTime aEndTime) {
+  mEndTime = aEndTime;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetEndTimeReference(uint32_t* _retval) {
+  *_retval = mEndTimeReference;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetEndTimeReference(uint32_t aReference) {
+  if (aReference > TIME_RELATIVE_NOW) return NS_ERROR_INVALID_ARG;
+  mEndTimeReference = aReference;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetHasEndTime(bool* _retval) {
+  *_retval = !(mEndTimeReference == TIME_RELATIVE_EPOCH && mEndTime == 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetAbsoluteEndTime(PRTime* _retval) {
+  *_retval = nsNavHistory::NormalizeTime(mEndTimeReference, mEndTime);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetSearchTerms(nsAString& aSearchTerms) {
+  aSearchTerms = mSearchTerms;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetSearchTerms(const nsAString& aSearchTerms) {
+  mSearchTerms = aSearchTerms;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::GetHasSearchTerms(bool* _retval) {
+  *_retval = (!mSearchTerms.IsEmpty());
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetMinVisits(int32_t* _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+  *_retval = mMinVisits;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetMinVisits(int32_t aVisits) {
+  mMinVisits = aVisits;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetMaxVisits(int32_t* _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+  *_retval = mMaxVisits;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetMaxVisits(int32_t aVisits) {
+  mMaxVisits = aVisits;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetDomainIsHost(bool* aDomainIsHost) {
+  *aDomainIsHost = mDomainIsHost;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetDomainIsHost(bool aDomainIsHost) {
+  mDomainIsHost = aDomainIsHost;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetDomain(nsACString& aDomain) {
+  aDomain = mDomain;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetDomain(const nsACString& aDomain) {
+  mDomain = aDomain;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::GetHasDomain(bool* _retval) {
+  // note that empty but not void is still a valid query (local files)
+  *_retval = (!mDomain.IsVoid());
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetUri(nsIURI** aUri) {
+  NS_IF_ADDREF(*aUri = mUri);
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::SetUri(nsIURI* aUri) {
+  mUri = aUri;
+  return NS_OK;
+}
+NS_IMETHODIMP nsNavHistoryQuery::GetHasUri(bool* aHasUri) {
+  *aHasUri = (mUri != nullptr);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetTags(nsIVariant** aTags) {
+  NS_ENSURE_ARG_POINTER(aTags);
+
+  RefPtr<nsVariant> out = new nsVariant();
+
+  uint32_t arrayLen = mTags.Length();
+
+  nsresult rv;
+  if (arrayLen == 0) {
+    rv = out->SetAsEmptyArray();
+  } else {
+    // Note: The resulting nsIVariant dupes both the array and its elements.
+    const char16_t** array = reinterpret_cast<const char16_t**>(
+        moz_xmalloc(arrayLen * sizeof(char16_t*)));
+    for (uint32_t i = 0; i < arrayLen; ++i) {
+      array[i] = mTags[i].get();
+    }
+
+    rv = out->SetAsArray(nsIDataType::VTYPE_WCHAR_STR, nullptr, arrayLen,
+                         reinterpret_cast<void*>(array));
+    free(array);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  out.forget(aTags);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::SetTags(nsIVariant* aTags) {
+  NS_ENSURE_ARG(aTags);
+
+  uint16_t dataType = aTags->GetDataType();
+
+  // Caller passed in empty array.  Easy -- clear our mTags array and return.
+  if (dataType == nsIDataType::VTYPE_EMPTY_ARRAY) {
+    mTags.Clear();
+    return NS_OK;
+  }
+
+  // Before we go any further, make sure caller passed in an array.
+  NS_ENSURE_TRUE(dataType == nsIDataType::VTYPE_ARRAY, NS_ERROR_ILLEGAL_VALUE);
+
+  uint16_t eltType;
+  nsIID eltIID;
+  uint32_t arrayLen;
+  void* array;
+
+  // Convert the nsIVariant to an array.  We own the resulting buffer and its
+  // elements.
+  nsresult rv = aTags->GetAsArray(&eltType, &eltIID, &arrayLen, &array);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If element type is not wstring, thanks a lot.  Your memory die now.
+  if (eltType != nsIDataType::VTYPE_WCHAR_STR) {
+    switch (eltType) {
+      case nsIDataType::VTYPE_ID:
+      case nsIDataType::VTYPE_CHAR_STR: {
+        char** charArray = reinterpret_cast<char**>(array);
+        for (uint32_t i = 0; i < arrayLen; ++i) {
+          if (charArray[i]) free(charArray[i]);
+        }
+      } break;
+      case nsIDataType::VTYPE_INTERFACE:
+      case nsIDataType::VTYPE_INTERFACE_IS: {
+        nsISupports** supportsArray = reinterpret_cast<nsISupports**>(array);
+        for (uint32_t i = 0; i < arrayLen; ++i) {
+          NS_IF_RELEASE(supportsArray[i]);
+        }
+      } break;
+        // The other types are primitives that do not need to be freed.
+    }
+    free(array);
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  char16_t** tags = reinterpret_cast<char16_t**>(array);
+  mTags.Clear();
+
+  // Finally, add each passed-in tag to our mTags array and then sort it.
+  for (uint32_t i = 0; i < arrayLen; ++i) {
+    // Don't allow nulls.
+    if (!tags[i]) {
+      free(tags);
+      return NS_ERROR_ILLEGAL_VALUE;
+    }
+
+    nsDependentString tag(tags[i]);
+
+    // Don't store duplicate tags.  This isn't just to save memory or to be
+    // fancy; the SQL that's built from the tags relies on no dupes.
+    if (!mTags.Contains(tag)) {
+      // XXX(Bug 1631371) Check if this should use a fallible operation as it
+      // pretended earlier.
+      mTags.AppendElement(tag);
+    }
+    free(tags[i]);
+  }
+  free(tags);
+
+  mTags.Sort();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetTagsAreNot(bool* aTagsAreNot) {
+  NS_ENSURE_ARG_POINTER(aTagsAreNot);
+  *aTagsAreNot = mTagsAreNot;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::SetTagsAreNot(bool aTagsAreNot) {
+  mTagsAreNot = aTagsAreNot;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetParents(nsTArray<nsCString>& aGuids) {
+  aGuids = mParents.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetParentCount(uint32_t* aGuidCount) {
+  *aGuidCount = mParents.Length();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::SetParents(const nsTArray<nsCString>& aGuids) {
+  mParents.Clear();
+  if (!mParents.Assign(aGuids, fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetTransitions(
+    nsTArray<uint32_t>& aTransitions) {
+  aTransitions = mTransitions.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::GetTransitionCount(uint32_t* aCount) {
+  *aCount = mTransitions.Length();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsNavHistoryQuery::SetTransitions(
+    const nsTArray<uint32_t>& aTransitions) {
+  if (!mTransitions.Assign(aTransitions, fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQuery::Clone(nsINavHistoryQuery** _clone) {
+  nsNavHistoryQuery* clone = nullptr;
+  Unused << Clone(&clone);
+  *_clone = clone;
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQuery::Clone(nsNavHistoryQuery** _clone) {
+  *_clone = nullptr;
+  RefPtr<nsNavHistoryQuery> clone = new nsNavHistoryQuery(*this);
+  clone.forget(_clone);
+  return NS_OK;
+}
+
+/* static */
+nsresult nsNavHistoryQuery::QueryStringToQuery(
+    const nsACString& aQueryString, nsINavHistoryQuery** _query,
+    nsINavHistoryQueryOptions** _options) {
+  NS_ENSURE_ARG_POINTER(_query);
+  NS_ENSURE_ARG_POINTER(_options);
+
+  nsTArray<QueryKeyValuePair> tokens;
+  nsresult rv = TokenizeQueryString(aQueryString, &tokens);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<nsNavHistoryQueryOptions> options = new nsNavHistoryQueryOptions();
+  RefPtr<nsNavHistoryQuery> query = new nsNavHistoryQuery();
+  rv = nsNavHistory::TokensToQuery(tokens, query, options);
+  MOZ_ASSERT(NS_SUCCEEDED(rv), "The query string should be valid");
+  if (NS_FAILED(rv)) {
+    NS_WARNING("Unable to parse the query string: ");
+    NS_WARNING(PromiseFlatCString(aQueryString).get());
+  }
+
+  options.forget(_options);
+  query.forget(_query);
+  return NS_OK;
+}
+
+// nsNavHistoryQueryOptions
+NS_IMPL_ISUPPORTS(nsNavHistoryQueryOptions, nsNavHistoryQueryOptions,
+                  nsINavHistoryQueryOptions)
+
+nsNavHistoryQueryOptions::nsNavHistoryQueryOptions()
+    : mSort(0),
+      mResultType(0),
+      mExcludeItems(false),
+      mExcludeQueries(false),
+      mExpandQueries(true),
+      mIncludeHidden(false),
+      mMaxResults(0),
+      mQueryType(nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY),
+      mAsyncEnabled(false) {}
+
+nsNavHistoryQueryOptions::nsNavHistoryQueryOptions(
+    const nsNavHistoryQueryOptions& other)
+    : mSort(other.mSort),
+      mResultType(other.mResultType),
+      mExcludeItems(other.mExcludeItems),
+      mExcludeQueries(other.mExcludeQueries),
+      mExpandQueries(other.mExpandQueries),
+      mIncludeHidden(other.mIncludeHidden),
+      mMaxResults(other.mMaxResults),
+      mQueryType(other.mQueryType),
+      mAsyncEnabled(other.mAsyncEnabled) {}
+
+// sortingMode
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetSortingMode(uint16_t* aMode) {
+  *aMode = mSort;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetSortingMode(uint16_t aMode) {
+  if (aMode > SORT_BY_FRECENCY_DESCENDING) return NS_ERROR_INVALID_ARG;
+  mSort = aMode;
+  return NS_OK;
+}
+
+// resultType
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetResultType(uint16_t* aType) {
+  *aType = mResultType;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetResultType(uint16_t aType) {
+  if (aType > RESULTS_AS_LEFT_PANE_QUERY) return NS_ERROR_INVALID_ARG;
+  // Tag queries, containers and the roots query are bookmarks related, so we
+  // set the QueryType accordingly.
+  if (aType == RESULTS_AS_TAGS_ROOT || aType == RESULTS_AS_ROOTS_QUERY ||
+      aType == RESULTS_AS_LEFT_PANE_QUERY) {
+    mQueryType = QUERY_TYPE_BOOKMARKS;
+  }
+  mResultType = aType;
+  return NS_OK;
+}
+
+// excludeItems
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetExcludeItems(bool* aExclude) {
+  *aExclude = mExcludeItems;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetExcludeItems(bool aExclude) {
+  mExcludeItems = aExclude;
+  return NS_OK;
+}
+
+// excludeQueries
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetExcludeQueries(bool* aExclude) {
+  *aExclude = mExcludeQueries;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetExcludeQueries(bool aExclude) {
+  mExcludeQueries = aExclude;
+  return NS_OK;
+}
+// expandQueries
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetExpandQueries(bool* aExpand) {
+  *aExpand = mExpandQueries;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetExpandQueries(bool aExpand) {
+  mExpandQueries = aExpand;
+  return NS_OK;
+}
+
+// includeHidden
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetIncludeHidden(bool* aIncludeHidden) {
+  *aIncludeHidden = mIncludeHidden;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetIncludeHidden(bool aIncludeHidden) {
+  mIncludeHidden = aIncludeHidden;
+  return NS_OK;
+}
+
+// maxResults
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetMaxResults(uint32_t* aMaxResults) {
+  *aMaxResults = mMaxResults;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetMaxResults(uint32_t aMaxResults) {
+  mMaxResults = aMaxResults;
+  return NS_OK;
+}
+
+// queryType
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetQueryType(uint16_t* _retval) {
+  *_retval = mQueryType;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetQueryType(uint16_t aQueryType) {
+  // Tag query and containers are forced to QUERY_TYPE_BOOKMARKS when the
+  // resultType is set.
+  if (mResultType == RESULTS_AS_TAGS_ROOT ||
+      mResultType == RESULTS_AS_LEFT_PANE_QUERY ||
+      mResultType == RESULTS_AS_ROOTS_QUERY) {
+    return NS_OK;
+  }
+  mQueryType = aQueryType;
+  return NS_OK;
+}
+
+// asyncEnabled
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::GetAsyncEnabled(bool* _asyncEnabled) {
+  *_asyncEnabled = mAsyncEnabled;
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::SetAsyncEnabled(bool aAsyncEnabled) {
+  mAsyncEnabled = aAsyncEnabled;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQueryOptions::Clone(nsINavHistoryQueryOptions** _clone) {
+  nsNavHistoryQueryOptions* clone = nullptr;
+  Unused << Clone(&clone);
+  *_clone = clone;
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryOptions::Clone(nsNavHistoryQueryOptions** _clone) {
+  *_clone = nullptr;
+  RefPtr<nsNavHistoryQueryOptions> clone = new nsNavHistoryQueryOptions(*this);
+  clone.forget(_clone);
+  return NS_OK;
+}
+
+// AppendBoolKeyValueIfTrue
+
+void  // static
+AppendBoolKeyValueIfTrue(nsACString& aString, const nsCString& aName,
+                         nsINavHistoryQuery* aQuery, BoolQueryGetter getter) {
+  bool value;
+  DebugOnly<nsresult> rv = (aQuery->*getter)(&value);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "Failure getting boolean value");
+  if (value) {
+    AppendAmpersandIfNonempty(aString);
+    aString += aName;
+    aString.AppendLiteral("=1");
+  }
+}
+
+// AppendUint32KeyValueIfNonzero
+
+void  // static
+AppendUint32KeyValueIfNonzero(nsACString& aString, const nsCString& aName,
+                              nsINavHistoryQuery* aQuery,
+                              Uint32QueryGetter getter) {
+  uint32_t value;
+  DebugOnly<nsresult> rv = (aQuery->*getter)(&value);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "Failure getting value");
+  if (value) {
+    AppendAmpersandIfNonempty(aString);
+    aString += aName;
+
+    // AppendInt requires a concrete string
+    nsAutoCString appendMe("=");
+    appendMe.AppendInt(value);
+    aString.Append(appendMe);
+  }
+}
+
+// AppendInt64KeyValueIfNonzero
+
+void  // static
+AppendInt64KeyValueIfNonzero(nsACString& aString, const nsCString& aName,
+                             nsINavHistoryQuery* aQuery,
+                             Int64QueryGetter getter) {
+  PRTime value;
+  DebugOnly<nsresult> rv = (aQuery->*getter)(&value);
+  NS_ASSERTION(NS_SUCCEEDED(rv), "Failure getting value");
+  if (value) {
+    AppendAmpersandIfNonempty(aString);
+    aString += aName;
+    nsAutoCString appendMe("=");
+    appendMe.AppendInt(static_cast<int64_t>(value));
+    aString.Append(appendMe);
+  }
+}
+
+// SetQuery/OptionsKeyBool
+
+void  // static
+SetQueryKeyBool(const nsCString& aValue, nsINavHistoryQuery* aQuery,
+                BoolQuerySetter setter) {
+  bool value;
+  nsresult rv = ParseQueryBooleanString(aValue, &value);
+  if (NS_SUCCEEDED(rv)) {
+    rv = (aQuery->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting boolean key value");
+    }
+  } else {
+    NS_WARNING("Invalid boolean key value in query string.");
+  }
+}
+void  // static
+SetOptionsKeyBool(const nsCString& aValue, nsINavHistoryQueryOptions* aOptions,
+                  BoolOptionsSetter setter) {
+  bool value = false;
+  nsresult rv = ParseQueryBooleanString(aValue, &value);
+  if (NS_SUCCEEDED(rv)) {
+    rv = (aOptions->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting boolean key value");
+    }
+  } else {
+    NS_WARNING("Invalid boolean key value in query string.");
+  }
+}
+
+// SetQuery/OptionsKeyUint32
+
+void  // static
+SetQueryKeyUint32(const nsCString& aValue, nsINavHistoryQuery* aQuery,
+                  Uint32QuerySetter setter) {
+  nsresult rv;
+  uint32_t value = aValue.ToInteger(&rv);
+  if (NS_SUCCEEDED(rv)) {
+    rv = (aQuery->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting Int32 key value");
+    }
+  } else {
+    NS_WARNING("Invalid Int32 key value in query string.");
+  }
+}
+void  // static
+SetOptionsKeyUint32(const nsCString& aValue,
+                    nsINavHistoryQueryOptions* aOptions,
+                    Uint32OptionsSetter setter) {
+  nsresult rv;
+  uint32_t value = aValue.ToInteger(&rv);
+  if (NS_SUCCEEDED(rv)) {
+    rv = (aOptions->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting Int32 key value");
+    }
+  } else {
+    NS_WARNING("Invalid Int32 key value in query string.");
+  }
+}
+
+void  // static
+SetOptionsKeyUint16(const nsCString& aValue,
+                    nsINavHistoryQueryOptions* aOptions,
+                    Uint16OptionsSetter setter) {
+  nsresult rv;
+  uint16_t value = static_cast<uint16_t>(aValue.ToInteger(&rv));
+  if (NS_SUCCEEDED(rv)) {
+    rv = (aOptions->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting Int16 key value");
+    }
+  } else {
+    NS_WARNING("Invalid Int16 key value in query string.");
+  }
+}
+
+// SetQueryKeyInt64
+
+void SetQueryKeyInt64(const nsCString& aValue, nsINavHistoryQuery* aQuery,
+                      Int64QuerySetter setter) {
+  nsresult rv;
+  int64_t value;
+  if (PR_sscanf(aValue.get(), "%lld", &value) == 1) {
+    rv = (aQuery->*setter)(value);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Error setting Int64 key value");
+    }
+  } else {
+    NS_WARNING("Invalid Int64 value in query string.");
+  }
+}
diff --git a/toolkit/components/places/nsNavHistoryQuery.h b/toolkit/components/places/nsNavHistoryQuery.h
new file mode 100644
index 0000000000..3f170a44ce
--- /dev/null
+++ b/toolkit/components/places/nsNavHistoryQuery.h
@@ -0,0 +1,141 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * The definitions of nsNavHistoryQuery and nsNavHistoryQueryOptions. This
+ * header file should only be included from nsNavHistory.h, include that if
+ * you want these classes.
+ */
+
+#ifndef nsNavHistoryQuery_h_
+#define nsNavHistoryQuery_h_
+
+// nsNavHistoryQuery
+//
+//    This class encapsulates the parameters for basic history queries for
+//    building UI, trees, lists, etc.
+
+#include "mozilla/Attributes.h"
+
+#define NS_NAVHISTORYQUERY_IID                       \
+  {                                                  \
+    0xb10185e0, 0x86eb, 0x4612, {                    \
+      0x95, 0x7c, 0x09, 0x34, 0xf2, 0xb1, 0xce, 0xd7 \
+    }                                                \
+  }
+
+class nsNavHistoryQuery final : public nsINavHistoryQuery {
+ public:
+  nsNavHistoryQuery();
+  nsNavHistoryQuery(const nsNavHistoryQuery& aOther);
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_NAVHISTORYQUERY_IID)
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSINAVHISTORYQUERY
+
+  int32_t MinVisits() { return mMinVisits; }
+  int32_t MaxVisits() { return mMaxVisits; }
+  PRTime BeginTime() { return mBeginTime; }
+  uint32_t BeginTimeReference() { return mBeginTimeReference; }
+  PRTime EndTime() { return mEndTime; }
+  uint32_t EndTimeReference() { return mEndTimeReference; }
+  const nsString& SearchTerms() { return mSearchTerms; }
+  bool DomainIsHost() { return mDomainIsHost; }
+  const nsCString& Domain() { return mDomain; }
+  nsIURI* Uri() { return mUri; }  // NOT AddRef-ed!
+  const nsTArray<nsCString>& Parents() const { return mParents; }
+
+  const nsTArray<nsString>& Tags() const { return mTags; }
+  void SetTags(nsTArray<nsString> aTags) { mTags = std::move(aTags); }
+  bool TagsAreNot() { return mTagsAreNot; }
+
+  const nsTArray<uint32_t>& Transitions() const { return mTransitions; }
+
+  nsresult Clone(nsNavHistoryQuery** _clone);
+
+  static nsresult QueryStringToQuery(const nsACString& aQueryString,
+                                     nsINavHistoryQuery** _query,
+                                     nsINavHistoryQueryOptions** _options);
+
+ private:
+  ~nsNavHistoryQuery() = default;
+
+ protected:
+  // IF YOU ADD MORE ITEMS:
+  //  * Add to the copy constructor
+  int32_t mMinVisits;
+  int32_t mMaxVisits;
+  PRTime mBeginTime;
+  uint32_t mBeginTimeReference;
+  PRTime mEndTime;
+  uint32_t mEndTimeReference;
+  nsString mSearchTerms;
+  bool mDomainIsHost;
+  nsCString mDomain;  // Default is IsVoid, empty string is valid query
+  nsCOMPtr<nsIURI> mUri;
+  nsTArray<nsCString> mParents;
+  nsTArray<nsString> mTags;
+  bool mTagsAreNot;
+  nsTArray<uint32_t> mTransitions;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsNavHistoryQuery, NS_NAVHISTORYQUERY_IID)
+
+// nsNavHistoryQueryOptions
+
+#define NS_NAVHISTORYQUERYOPTIONS_IID                \
+  {                                                  \
+    0x95f8ba3b, 0xd681, 0x4d89, {                    \
+      0xab, 0xd1, 0xfd, 0xae, 0xf2, 0xa3, 0xde, 0x18 \
+    }                                                \
+  }
+
+class nsNavHistoryQueryOptions final : public nsINavHistoryQueryOptions {
+ public:
+  nsNavHistoryQueryOptions();
+  nsNavHistoryQueryOptions(const nsNavHistoryQueryOptions& other);
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_NAVHISTORYQUERYOPTIONS_IID)
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSINAVHISTORYQUERYOPTIONS
+
+  uint16_t SortingMode() const { return mSort; }
+  uint16_t ResultType() const { return mResultType; }
+  bool ExcludeItems() const { return mExcludeItems; }
+  bool ExcludeQueries() const { return mExcludeQueries; }
+  bool ExpandQueries() const { return mExpandQueries; }
+  bool IncludeHidden() const { return mIncludeHidden; }
+  uint32_t MaxResults() const { return mMaxResults; }
+  uint16_t QueryType() const { return mQueryType; }
+  bool AsyncEnabled() const { return mAsyncEnabled; }
+
+  nsresult Clone(nsNavHistoryQueryOptions** _clone);
+
+ private:
+  ~nsNavHistoryQueryOptions() = default;
+
+  // IF YOU ADD MORE ITEMS:
+  //  * Add to the copy constructor
+  //  * Add a new getter for C++ above if it makes sense
+  //  * Add to the serialization code (see nsNavHistory::QueriesToQueryString())
+  //  * Add to the deserialization code (see nsNavHistory::QueryStringToQueries)
+  //  * Add to the nsNavHistory.cpp::GetSimpleBookmarksQueryFolder function if
+  //  applicable
+  uint16_t mSort;
+  uint16_t mResultType;
+  bool mExcludeItems;
+  bool mExcludeQueries;
+  bool mExpandQueries;
+  bool mIncludeHidden;
+  uint32_t mMaxResults;
+  uint16_t mQueryType;
+  bool mAsyncEnabled;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsNavHistoryQueryOptions,
+                              NS_NAVHISTORYQUERYOPTIONS_IID)
+
+#endif  // nsNavHistoryQuery_h_
diff --git a/toolkit/components/places/nsNavHistoryResult.cpp b/toolkit/components/places/nsNavHistoryResult.cpp
new file mode 100644
index 0000000000..45d6fc34be
--- /dev/null
+++ b/toolkit/components/places/nsNavHistoryResult.cpp
@@ -0,0 +1,4476 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include "nsNavHistory.h"
+#include "nsNavBookmarks.h"
+#include "nsFaviconService.h"
+#include "Helpers.h"
+#include "mozilla/DebugOnly.h"
+#include "nsDebug.h"
+#include "nsNetUtil.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsUnicharUtils.h"
+#include "prtime.h"
+#include "mozIStorageRow.h"
+#include "mozIStorageResultSet.h"
+#include "nsQueryObject.h"
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/dom/PlacesVisit.h"
+#include "mozilla/dom/PlacesVisitRemoved.h"
+#include "mozilla/dom/PlacesVisitTitle.h"
+#include "mozilla/dom/PlacesBookmarkAddition.h"
+#include "mozilla/dom/PlacesBookmarkRemoved.h"
+#include "mozilla/dom/PlacesBookmarkMoved.h"
+#include "mozilla/dom/PlacesBookmarkKeyword.h"
+#include "mozilla/dom/PlacesBookmarkTags.h"
+#include "mozilla/dom/PlacesBookmarkTime.h"
+#include "mozilla/dom/PlacesBookmarkTitle.h"
+#include "mozilla/dom/PlacesBookmarkUrl.h"
+#include "mozilla/dom/PlacesFavicon.h"
+
+#include "nsCycleCollectionParticipant.h"
+
+// Thanks, Windows.h :(
+#undef CompareString
+
+#define TO_ICONTAINER(_node) \
+  static_cast<nsINavHistoryContainerResultNode*>(_node)
+
+#define TO_CONTAINER(_node) static_cast<nsNavHistoryContainerResultNode*>(_node)
+
+#define NOTIFY_RESULT_OBSERVERS_RET(_result, _method, _ret)               \
+  PR_BEGIN_MACRO                                                          \
+  NS_ENSURE_TRUE(_result, _ret);                                          \
+  if (!_result->mSuppressNotifications) {                                 \
+    ENUMERATE_WEAKARRAY(_result->mObservers, nsINavHistoryResultObserver, \
+                        _method)                                          \
+  }                                                                       \
+  PR_END_MACRO
+
+#define NOTIFY_RESULT_OBSERVERS(_result, _method) \
+  NOTIFY_RESULT_OBSERVERS_RET(_result, _method, NS_ERROR_UNEXPECTED)
+
+// What we want is: NS_INTERFACE_MAP_ENTRY(self) for static IID accessors,
+// but some of our classes (like nsNavHistoryResult) have an ambiguous base
+// class of nsISupports which prevents this from working (the default macro
+// converts it to nsISupports, then addrefs it, then returns it). Therefore, we
+// expand the macro here and change it so that it works. Yuck.
+#define NS_INTERFACE_MAP_STATIC_AMBIGUOUS(_class) \
+  if (aIID.Equals(NS_GET_IID(_class))) {          \
+    NS_ADDREF(this);                              \
+    *aInstancePtr = this;                         \
+    return NS_OK;                                 \
+  } else
+
+// Number of changes to handle separately in a batch.  If more changes are
+// requested the node will switch to full refresh mode.
+#define MAX_BATCH_CHANGES_BEFORE_REFRESH 5
+
+// Number of Page_removed events to handle by simply refreshing all containers,
+// because doing so is much faster than incremental updates.
+#define MAX_PAGE_REMOVES_BEFORE_REFRESH 10
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::places;
+
+namespace {
+
+/**
+ * Returns conditions for query update.
+ *  QUERYUPDATE_TIME:
+ *    This query is only limited by an inclusive time range on the first
+ *    query object. The caller can quickly evaluate the time itself if it
+ *    chooses. This is even simpler than "simple" below.
+ *  QUERYUPDATE_SIMPLE:
+ *    This query is evaluatable using evaluateQueryForNode to do live
+ *    updating.
+ *  QUERYUPDATE_COMPLEX:
+ *    This query is not evaluatable using evaluateQueryForNode. When something
+ *    happens that this query updates, you will need to re-run the query.
+ *  QUERYUPDATE_COMPLEX_WITH_BOOKMARKS:
+ *    A complex query that additionally has dependence on bookmarks. All
+ *    bookmark-dependent queries fall under this category.
+ *  QUERYUPDATE_MOBILEPREF:
+ *    A complex query but only updates when the mobile preference changes.
+ *  QUERYUPDATE_NONE:
+ *    A query that never updates, e.g. the left-pane root query.
+ *
+ *  aHasSearchTerms will be set to true if the query has any dependence on
+ *  keywords. When there is no dependence on keywords, we can handle title
+ *  change operations as simple instead of complex.
+ */
+uint32_t getUpdateRequirements(const RefPtr<nsNavHistoryQuery>& aQuery,
+                               const RefPtr<nsNavHistoryQueryOptions>& aOptions,
+                               bool* aHasSearchTerms) {
+  // first check if there are search terms
+  bool hasSearchTerms = *aHasSearchTerms = !aQuery->SearchTerms().IsEmpty();
+
+  bool nonTimeBasedItems = false;
+  bool domainBasedItems = false;
+
+  if (aQuery->Parents().Length() > 0 || aQuery->Tags().Length() > 0 ||
+      (aOptions->QueryType() ==
+           nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS &&
+       hasSearchTerms)) {
+    return QUERYUPDATE_COMPLEX_WITH_BOOKMARKS;
+  }
+
+  // Note: we don't currently have any complex non-bookmarked items, but these
+  // are expected to be added. Put detection of these items here.
+  if (hasSearchTerms || !aQuery->Domain().IsVoid() ||
+      aQuery->Uri() != nullptr) {
+    nonTimeBasedItems = true;
+  }
+
+  if (!aQuery->Domain().IsVoid()) {
+    domainBasedItems = true;
+  }
+
+  if (aOptions->ResultType() ==
+      nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT) {
+    return QUERYUPDATE_COMPLEX_WITH_BOOKMARKS;
+  }
+
+  if (aOptions->ResultType() ==
+      nsINavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY) {
+    return QUERYUPDATE_MOBILEPREF;
+  }
+
+  if (aOptions->ResultType() ==
+      nsINavHistoryQueryOptions::RESULTS_AS_LEFT_PANE_QUERY) {
+    return QUERYUPDATE_NONE;
+  }
+
+  // Whenever there is a maximum number of results,
+  // and we are not a bookmark query we must requery. This
+  // is because we can't generally know if any given addition/change causes
+  // the item to be in the top N items in the database.
+  uint16_t sortingMode = aOptions->SortingMode();
+  if (aOptions->MaxResults() > 0 &&
+      sortingMode != nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING &&
+      sortingMode != nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING) {
+    return QUERYUPDATE_COMPLEX;
+  }
+
+  if (domainBasedItems) return QUERYUPDATE_HOST;
+  if (!nonTimeBasedItems) return QUERYUPDATE_TIME;
+
+  return QUERYUPDATE_SIMPLE;
+}
+
+/**
+ * We might have interesting encodings and different case in the host name.
+ * This will convert that host name into an ASCII host name by sending it
+ * through the URI canonicalization. The result can be used for comparison
+ * with other ASCII host name strings.
+ */
+nsresult asciiHostNameFromHostString(const nsACString& aHostName,
+                                     nsACString& aAscii) {
+  aAscii.Truncate();
+  if (aHostName.IsEmpty()) {
+    return NS_OK;
+  }
+  // To properly generate a uri we must provide a protocol.
+  nsAutoCString fakeURL("http://");
+  fakeURL.Append(aHostName);
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), fakeURL);
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = uri->GetAsciiHost(aAscii);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+bool isQueryMatchingVisitDetails(
+    const RefPtr<nsNavHistoryQuery>& query,
+    const RefPtr<nsNavHistoryQueryOptions>& options, bool hidden,
+    PRTime visitTime, uint32_t transition, nsIURI* uri) {
+  if (hidden && !options->IncludeHidden()) {
+    return false;
+  }
+
+  bool hasIt;
+  if (NS_SUCCEEDED(query->GetHasBeginTime(&hasIt)) && hasIt) {
+    PRTime beginTime = nsNavHistory::NormalizeTime(query->BeginTimeReference(),
+                                                   query->BeginTime());
+    if (visitTime < beginTime) {
+      return false;
+    }
+  }
+  if (NS_SUCCEEDED(query->GetHasEndTime(&hasIt)) && hasIt) {
+    PRTime endTime = nsNavHistory::NormalizeTime(query->EndTimeReference(),
+                                                 query->EndTime());
+    if (visitTime > endTime) {
+      return false;
+    }
+  }
+
+  const nsTArray<uint32_t>& transitions = query->Transitions();
+  if (transition > 0 && transitions.Length() &&
+      !transitions.Contains(transition)) {
+    return false;
+  }
+
+  if (!query->Domain().IsVoid()) {
+    nsAutoCString asciiRequest;
+    if (NS_FAILED(asciiHostNameFromHostString(query->Domain(), asciiRequest))) {
+      return false;
+    }
+    if (query->DomainIsHost()) {
+      // Exact domain match.
+      nsAutoCString host;
+      if (NS_FAILED(uri->GetAsciiHost(host)) || !asciiRequest.Equals(host)) {
+        return false;
+      }
+    } else {
+      // Wildcard domain match, subdomains are included.
+      nsNavHistory* history = nsNavHistory::GetHistoryService();
+      if (history) {
+        nsAutoCString domain;
+        history->DomainNameFromURI(uri, domain);
+        if (!asciiRequest.Equals(domain)) {
+          return false;
+        }
+      }
+    }
+  }
+
+  if (query->Uri()) {
+    bool equals;
+    if (NS_FAILED(query->Uri()->Equals(uri, &equals)) || !equals) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+inline bool isTimeFilteredQuery(const RefPtr<nsNavHistoryQuery>& query) {
+  bool hasIt;
+  return (NS_SUCCEEDED(query->GetHasBeginTime(&hasIt)) && hasIt) ||
+         (NS_SUCCEEDED(query->GetHasEndTime(&hasIt)) && hasIt);
+}
+
+inline bool caseInsensitiveFind(const nsACString& aSearchTerms,
+                                const nsACString& aTarget) {
+  nsACString::const_iterator start, end;
+  aTarget.BeginReading(start);
+  aTarget.EndReading(end);
+  return CaseInsensitiveFindInReadable(aSearchTerms, start, end);
+}
+
+bool isQuerySearchTermsMatching(const RefPtr<nsNavHistoryQuery>& aQuery,
+                                const nsACString& aURI,
+                                const nsACString& aTitle,
+                                const nsAString& aTags) {
+  nsAutoCString searchTerms = NS_ConvertUTF16toUTF8(aQuery->SearchTerms());
+  if ((!aTitle.IsEmpty() && caseInsensitiveFind(searchTerms, aTitle)) ||
+      (!aURI.IsEmpty() && caseInsensitiveFind(searchTerms, aURI))) {
+    return true;
+  }
+
+  if (aTags.IsEmpty()) {
+    return false;
+  }
+  for (const nsAString& tag : aTags.Split(',')) {
+    if (caseInsensitiveFind(searchTerms, NS_ConvertUTF16toUTF8(tag))) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool isQuerySearchTermsMatching(const RefPtr<nsNavHistoryQuery>& aQuery,
+                                const RefPtr<nsNavHistoryResultNode>& aNode) {
+  return isQuerySearchTermsMatching(aQuery, aNode->mURI, aNode->mTitle,
+                                    aNode->mTags);
+}
+
+// Emulate string comparison (used for sorting) for PRTime and int.
+inline int32_t ComparePRTime(PRTime a, PRTime b) {
+  if (a == b) {
+    return 0;
+  }
+  return a < b ? -1 : 1;
+}
+inline int32_t CompareIntegers(uint32_t a, uint32_t b) {
+  // These are unlikely to overflow, so just cast for now.
+  return static_cast<int32_t>(a) - static_cast<int32_t>(b);
+}
+
+}  // anonymous namespace
+
+NS_IMPL_CYCLE_COLLECTION(nsNavHistoryResultNode, mParent)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsNavHistoryResultNode)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsINavHistoryResultNode)
+  NS_INTERFACE_MAP_ENTRY(nsINavHistoryResultNode)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsNavHistoryResultNode)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsNavHistoryResultNode)
+
+nsNavHistoryResultNode::nsNavHistoryResultNode(const nsACString& aURI,
+                                               const nsACString& aTitle,
+                                               uint32_t aAccessCount,
+                                               PRTime aTime)
+    : mParent(nullptr),
+      mURI(aURI),
+      mTitle(aTitle),
+      mAccessCount(aAccessCount),
+      mTime(aTime),
+      mBookmarkIndex(-1),
+      mItemId(-1),
+      mVisitId(-1),
+      mDateAdded(0),
+      mLastModified(0),
+      mIndentLevel(-1),
+      mFrecency(0),
+      mHidden(false),
+      mTransitionType(0) {
+  mTags.SetIsVoid(true);
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetIcon(nsACString& aIcon) {
+  if (this->IsContainer() || mURI.IsEmpty()) {
+    return NS_OK;
+  }
+
+  aIcon.AppendLiteral("page-icon:");
+  aIcon.Append(mURI);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetParent(nsINavHistoryContainerResultNode** aParent) {
+  NS_IF_ADDREF(*aParent = mParent);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetParentResult(nsINavHistoryResult** aResult) {
+  *aResult = nullptr;
+  if (IsContainer()) {
+    NS_IF_ADDREF(*aResult = GetAsContainer()->mResult);
+  } else if (mParent) {
+    NS_IF_ADDREF(*aResult = mParent->mResult);
+  }
+
+  NS_ENSURE_STATE(*aResult);
+  return NS_OK;
+}
+
+void nsNavHistoryResultNode::SetTags(const nsAString& aTags) {
+  if (aTags.IsVoid()) {
+    mTags.SetIsVoid(true);
+    return;
+  }
+
+  mTags.Assign(aTags);
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetTags(nsAString& aTags) {
+  if (mTags.IsVoid()) {
+    aTags.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  aTags.Assign(mTags);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetPageGuid(nsACString& aPageGuid) {
+  aPageGuid = mPageGuid;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetBookmarkGuid(nsACString& aBookmarkGuid) {
+  aBookmarkGuid = mBookmarkGuid;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetVisitId(int64_t* aVisitId) {
+  *aVisitId = mVisitId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResultNode::GetVisitType(uint32_t* aVisitType) {
+  *aVisitType = mTransitionType;
+  return NS_OK;
+}
+
+void nsNavHistoryResultNode::OnRemoving() { mParent = nullptr; }
+
+/**
+ * This will find the result for this node.  We can ask the nearest container
+ * for this value (either ourselves or our parents should be a container,
+ * and all containers have result pointers).
+ *
+ * @note The result may be null, if the container is detached from the result
+ *       who owns it.
+ */
+nsNavHistoryResult* nsNavHistoryResultNode::GetResult() {
+  nsNavHistoryResultNode* node = this;
+  do {
+    if (node->IsContainer()) {
+      nsNavHistoryContainerResultNode* container = TO_CONTAINER(node);
+      return container->mResult;
+    }
+    node = node->mParent;
+  } while (node);
+  MOZ_ASSERT(false, "No container node found in hierarchy!");
+  return nullptr;
+}
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(nsNavHistoryContainerResultNode,
+                                   nsNavHistoryResultNode, mResult, mChildren)
+
+NS_IMPL_ADDREF_INHERITED(nsNavHistoryContainerResultNode,
+                         nsNavHistoryResultNode)
+NS_IMPL_RELEASE_INHERITED(nsNavHistoryContainerResultNode,
+                          nsNavHistoryResultNode)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsNavHistoryContainerResultNode)
+  NS_INTERFACE_MAP_STATIC_AMBIGUOUS(nsNavHistoryContainerResultNode)
+  NS_INTERFACE_MAP_ENTRY(nsINavHistoryContainerResultNode)
+NS_INTERFACE_MAP_END_INHERITING(nsNavHistoryResultNode)
+
+nsNavHistoryContainerResultNode::nsNavHistoryContainerResultNode(
+    const nsACString& aURI, const nsACString& aTitle, PRTime aTime,
+    uint32_t aContainerType, nsNavHistoryQueryOptions* aOptions)
+    : nsNavHistoryResultNode(aURI, aTitle, 0, aTime),
+      mResult(nullptr),
+      mContainerType(aContainerType),
+      mExpanded(false),
+      mOptions(aOptions),
+      mAsyncCanceledState(NOT_CANCELED) {
+  MOZ_ASSERT(mOptions);
+  MOZ_ALWAYS_SUCCEEDS(mOptions->Clone(getter_AddRefs(mOriginalOptions)));
+}
+
+nsNavHistoryContainerResultNode::~nsNavHistoryContainerResultNode() {
+  // Explicitly clean up array of children of this container.  We must ensure
+  // all references are gone and all of their destructors are called.
+  mChildren.Clear();
+}
+
+/**
+ * Containers should notify their children that they are being removed when the
+ * container is being removed.
+ */
+void nsNavHistoryContainerResultNode::OnRemoving() {
+  nsNavHistoryResultNode::OnRemoving();
+  for (nsNavHistoryResultNode* child : mChildren) {
+    child->OnRemoving();
+  }
+  mChildren.Clear();
+  mResult = nullptr;
+}
+
+bool nsNavHistoryContainerResultNode::AreChildrenVisible() {
+  nsNavHistoryResult* result = GetResult();
+  if (!result) {
+    MOZ_ASSERT_UNREACHABLE("Invalid result");
+    return false;
+  }
+
+  if (!mExpanded) return false;
+
+  // Now check if any ancestor is closed.
+  nsNavHistoryContainerResultNode* ancestor = mParent;
+  while (ancestor) {
+    if (!ancestor->mExpanded) return false;
+
+    ancestor = ancestor->mParent;
+  }
+
+  return true;
+}
+
+nsresult nsNavHistoryContainerResultNode::OnVisitsRemoved(nsIURI* aURI) {
+  if (!AreChildrenVisible()) {
+    return NS_OK;
+  }
+
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->CanSkipHistoryDetailsNotifications()) {
+    return NS_OK;
+  }
+
+  nsAutoCString spec;
+  nsresult rv = aURI->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMArray<nsNavHistoryResultNode> nodes;
+  FindChildrenByURI(spec, &nodes);
+  for (int32_t i = 0; i < nodes.Count(); i++) {
+    nodes[i]->OnVisitsRemoved();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetContainerOpen(bool* aContainerOpen) {
+  *aContainerOpen = mExpanded;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::SetContainerOpen(bool aContainerOpen) {
+  if (aContainerOpen) {
+    if (!mExpanded) {
+      if (mOptions->AsyncEnabled()) {
+        OpenContainerAsync();
+      } else {
+        OpenContainer();
+      }
+    }
+  } else {
+    if (mExpanded) {
+      CloseContainer();
+    } else if (mAsyncPendingStmt) {
+      CancelAsyncOpen(false);
+    }
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Notifies the result's observers of a change in the container's state.  The
+ * notification includes both the old and new states:  The old is aOldState, and
+ * the new is the container's current state.
+ *
+ * @param aOldState
+ *        The state being transitioned out of.
+ */
+nsresult nsNavHistoryContainerResultNode::NotifyOnStateChange(
+    uint16_t aOldState) {
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+
+  nsresult rv;
+  uint16_t currState;
+  rv = GetState(&currState);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Notify via the new ContainerStateChanged observer method.
+  NOTIFY_RESULT_OBSERVERS(result,
+                          ContainerStateChanged(this, aOldState, currState));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetState(uint16_t* _state) {
+  NS_ENSURE_ARG_POINTER(_state);
+
+  *_state = mExpanded           ? (uint16_t)STATE_OPENED
+            : mAsyncPendingStmt ? (uint16_t)STATE_LOADING
+                                : (uint16_t)STATE_CLOSED;
+
+  return NS_OK;
+}
+
+/**
+ * This handles the generic container case.  Other container types should
+ * override this to do their own handling.
+ */
+nsresult nsNavHistoryContainerResultNode::OpenContainer() {
+  NS_ASSERTION(!mExpanded, "Container must not be expanded to open it");
+  mExpanded = true;
+
+  nsresult rv = NotifyOnStateChange(STATE_CLOSED);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+/**
+ * Unset aSuppressNotifications to notify observers on this change.  That is
+ * the normal operation.  This is set to false for the recursive calls since the
+ * root container that is being closed will handle recomputation of the visible
+ * elements for its entire subtree.
+ */
+nsresult nsNavHistoryContainerResultNode::CloseContainer(
+    bool aSuppressNotifications) {
+  NS_ASSERTION(
+      (mExpanded && !mAsyncPendingStmt) || (!mExpanded && mAsyncPendingStmt),
+      "Container must be expanded or loading to close it");
+
+  nsresult rv;
+  uint16_t oldState;
+  rv = GetState(&oldState);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mExpanded) {
+    // Recursively close all child containers.
+    for (int32_t i = 0; i < mChildren.Count(); ++i) {
+      if (mChildren[i]->IsContainer() &&
+          mChildren[i]->GetAsContainer()->mExpanded) {
+        mChildren[i]->GetAsContainer()->CloseContainer(true);
+      }
+    }
+
+    mExpanded = false;
+  }
+
+  // Be sure to set this to null before notifying observers.  It signifies that
+  // the container is no longer loading (if it was in the first place).
+  mAsyncPendingStmt = nullptr;
+
+  if (!aSuppressNotifications) {
+    rv = NotifyOnStateChange(oldState);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // If this is the root container of a result, we can tell the result to stop
+  // observing changes, otherwise the result will stay in memory and updates
+  // itself till it is cycle collected.
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->mRootNode == this) {
+    result->StopObserving();
+    // When reopening this node its result will be out of sync.
+    // We must clear our children to ensure we will call FillChildren
+    // again in such a case.
+    if (this->IsQuery()) {
+      this->GetAsQuery()->ClearChildren(true);
+    } else if (this->IsFolder()) {
+      this->GetAsFolder()->ClearChildren(true);
+    }
+  }
+
+  return NS_OK;
+}
+
+/**
+ * The async version of OpenContainer.
+ */
+nsresult nsNavHistoryContainerResultNode::OpenContainerAsync() {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/**
+ * Cancels the pending asynchronous Storage execution triggered by
+ * FillChildrenAsync, if it exists.  This method doesn't do much, because after
+ * cancelation Storage will call this node's HandleCompletion callback, where
+ * the real work is done.
+ *
+ * @param aRestart
+ *        If true, async execution will be restarted by HandleCompletion.
+ */
+void nsNavHistoryContainerResultNode::CancelAsyncOpen(bool aRestart) {
+  NS_ASSERTION(mAsyncPendingStmt, "Async execution canceled but not pending");
+
+  mAsyncCanceledState = aRestart ? CANCELED_RESTART_NEEDED : CANCELED;
+
+  // Cancel will fail if the pending statement has already been canceled.
+  // That's OK since this method may be called multiple times, and multiple
+  // cancels don't harm anything.
+  (void)mAsyncPendingStmt->Cancel();
+}
+
+/**
+ * This builds up tree statistics from the bottom up.  Call with a container
+ * and the indent level of that container.  To init the full tree, call with
+ * the root container.  The default indent level is -1, which is appropriate
+ * for the root level.
+ *
+ * CALL THIS AFTER FILLING ANY CONTAINER to update the parent and result node
+ * pointers, even if you don't care about visit counts and last visit dates.
+ */
+void nsNavHistoryContainerResultNode::FillStats() {
+  uint32_t accessCount = 0;
+  PRTime newTime = 0;
+
+  for (nsNavHistoryResultNode* node : mChildren) {
+    SetAsParentOfNode(node);
+    accessCount += node->mAccessCount;
+    // this is how container nodes get sorted by date
+    // The container gets the most recent time of the child nodes.
+    if (node->mTime > newTime) {
+      newTime = node->mTime;
+    }
+  }
+
+  if (mExpanded) {
+    mAccessCount = accessCount;
+    if (!IsQuery() || newTime > mTime) {
+      mTime = newTime;
+    }
+  }
+}
+
+void nsNavHistoryContainerResultNode::SetAsParentOfNode(
+    nsNavHistoryResultNode* aNode) {
+  aNode->mParent = this;
+  aNode->mIndentLevel = mIndentLevel + 1;
+  if (aNode->IsContainer()) {
+    nsNavHistoryContainerResultNode* container = aNode->GetAsContainer();
+    // Propagate some of the parent's options to this container.
+    if (mOptions->ExcludeItems()) {
+      container->mOptions->SetExcludeItems(true);
+    }
+    if (mOptions->ExcludeQueries()) {
+      container->mOptions->SetExcludeQueries(true);
+    }
+    if (aNode->IsFolder() && mOptions->AsyncEnabled()) {
+      container->mOptions->SetAsyncEnabled(true);
+    }
+    if (!mOptions->ExpandQueries()) {
+      container->mOptions->SetExpandQueries(false);
+    }
+    container->mResult = mResult;
+    container->FillStats();
+  }
+}
+
+/**
+ * This is used when one container changes to do a minimal update of the tree
+ * structure.  When something changes, you want to call FillStats if necessary
+ * and update this container completely.  Then call this function which will
+ * walk up the tree and fill in the previous containers.
+ *
+ * Note that you have to tell us by how much our access count changed.  Our
+ * access count should already be set to the new value; this is used tochange
+ * the parents without having to re-count all their children.
+ *
+ * This does NOT update the last visit date downward.  Therefore, if you are
+ * deleting a node that has the most recent last visit date, the parents will
+ * not get their last visit dates downshifted accordingly.  This is a rather
+ * unusual case: we don't often delete things, and we usually don't even show
+ * the last visit date for folders.  Updating would be slower because we would
+ * have to recompute it from scratch.
+ */
+nsresult nsNavHistoryContainerResultNode::ReverseUpdateStats(
+    int32_t aAccessCountChange) {
+  if (mParent) {
+    nsNavHistoryResult* result = GetResult();
+    bool shouldNotify =
+        result && mParent->mParent && mParent->mParent->AreChildrenVisible();
+
+    uint32_t oldAccessCount = mParent->mAccessCount;
+    PRTime oldTime = mParent->mTime;
+
+    mParent->mAccessCount += aAccessCountChange;
+    bool timeChanged = false;
+    if (mTime > mParent->mTime) {
+      timeChanged = true;
+      mParent->mTime = mTime;
+    }
+
+    if (shouldNotify && !result->CanSkipHistoryDetailsNotifications()) {
+      NOTIFY_RESULT_OBSERVERS(
+          result, NodeHistoryDetailsChanged(TO_ICONTAINER(mParent), oldTime,
+                                            oldAccessCount));
+    }
+
+    // check sorting, the stats may have caused this node to move if the
+    // sorting depended on something we are changing.
+    uint16_t sortMode = mParent->GetSortType();
+    bool sortingByVisitCount =
+        sortMode == nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING ||
+        sortMode == nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING;
+    bool sortingByTime =
+        sortMode == nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING ||
+        sortMode == nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING;
+
+    if ((sortingByVisitCount && aAccessCountChange != 0) ||
+        (sortingByTime && timeChanged)) {
+      int32_t ourIndex = mParent->FindChild(this);
+      NS_ASSERTION(ourIndex >= 0, "Could not find self in parent");
+      if (ourIndex >= 0) {
+        EnsureItemPosition(ourIndex);
+      }
+    }
+
+    nsresult rv = mParent->ReverseUpdateStats(aAccessCountChange);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * This walks up the tree until we find a query result node or the root to get
+ * the sorting type.
+ */
+uint16_t nsNavHistoryContainerResultNode::GetSortType() {
+  if (mParent) return mParent->GetSortType();
+  if (mResult) return mResult->mSortingMode;
+
+  // This is a detached container, just use natural order.
+  return nsINavHistoryQueryOptions::SORT_BY_NONE;
+}
+
+nsresult nsNavHistoryContainerResultNode::Refresh() {
+  NS_WARNING(
+      "Refresh() is supported by queries or folders, not generic containers.");
+  return NS_OK;
+}
+
+/**
+ * @return the sorting comparator function for the give sort type, or null if
+ * there is no comparator.
+ */
+nsNavHistoryContainerResultNode::SortComparator
+nsNavHistoryContainerResultNode::GetSortingComparator(uint16_t aSortType) {
+  switch (aSortType) {
+    case nsINavHistoryQueryOptions::SORT_BY_NONE:
+      return &SortComparison_Bookmark;
+    case nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING:
+      return &SortComparison_TitleLess;
+    case nsINavHistoryQueryOptions::SORT_BY_TITLE_DESCENDING:
+      return &SortComparison_TitleGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING:
+      return &SortComparison_DateLess;
+    case nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING:
+      return &SortComparison_DateGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_URI_ASCENDING:
+      return &SortComparison_URILess;
+    case nsINavHistoryQueryOptions::SORT_BY_URI_DESCENDING:
+      return &SortComparison_URIGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING:
+      return &SortComparison_VisitCountLess;
+    case nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING:
+      return &SortComparison_VisitCountGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_DATEADDED_ASCENDING:
+      return &SortComparison_DateAddedLess;
+    case nsINavHistoryQueryOptions::SORT_BY_DATEADDED_DESCENDING:
+      return &SortComparison_DateAddedGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_LASTMODIFIED_ASCENDING:
+      return &SortComparison_LastModifiedLess;
+    case nsINavHistoryQueryOptions::SORT_BY_LASTMODIFIED_DESCENDING:
+      return &SortComparison_LastModifiedGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_TAGS_ASCENDING:
+      return &SortComparison_TagsLess;
+    case nsINavHistoryQueryOptions::SORT_BY_TAGS_DESCENDING:
+      return &SortComparison_TagsGreater;
+    case nsINavHistoryQueryOptions::SORT_BY_FRECENCY_ASCENDING:
+      return &SortComparison_FrecencyLess;
+    case nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING:
+      return &SortComparison_FrecencyGreater;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Bad sorting type");
+      return nullptr;
+  }
+}
+
+/**
+ * This is used by Result::SetSortingMode and QueryResultNode::FillChildren to
+ * sort the child list.
+ *
+ * This does NOT update any visibility or tree information.  The caller will
+ * have to completely rebuild the visible list after this.
+ */
+void nsNavHistoryContainerResultNode::RecursiveSort(
+    SortComparator aComparator) {
+  mChildren.Sort(aComparator);
+  for (nsNavHistoryResultNode* child : mChildren) {
+    if (child->IsContainer()) {
+      child->GetAsContainer()->RecursiveSort(aComparator);
+    }
+  }
+}
+
+/**
+ * @return the index that the given item would fall on if it were to be
+ * inserted using the given sorting.
+ */
+int32_t nsNavHistoryContainerResultNode::FindInsertionPoint(
+    nsNavHistoryResultNode* aNode, SortComparator aComparator,
+    bool* aItemExists) {
+  if (aItemExists) {
+    (*aItemExists) = false;
+  }
+
+  if (mChildren.Count() == 0) return 0;
+
+  // The common case is the beginning or the end because this is used to insert
+  // new items that are added to history, which is usually sorted by date.
+  int32_t res;
+  res = aComparator(aNode, mChildren[0]);
+  if (res <= 0) {
+    if (aItemExists && res == 0) {
+      (*aItemExists) = true;
+    }
+    return 0;
+  }
+  res = aComparator(aNode, mChildren[mChildren.Count() - 1]);
+  if (res >= 0) {
+    if (aItemExists && res == 0) {
+      (*aItemExists) = true;
+    }
+    return mChildren.Count();
+  }
+
+  int32_t beginRange = 0;                // inclusive
+  int32_t endRange = mChildren.Count();  // exclusive
+  while (beginRange < endRange) {
+    int32_t center = beginRange + (endRange - beginRange) / 2;
+    int32_t res = aComparator(aNode, mChildren[center]);
+    if (res <= 0) {
+      endRange = center;  // left side
+      if (aItemExists && res == 0) {
+        (*aItemExists) = true;
+      }
+    } else {
+      beginRange = center + 1;  // right site
+    }
+  }
+  return endRange;
+}
+
+/**
+ * This checks the child node at the given index to see if its sorting is
+ * correct.  This is called when nodes are updated and we need to see whether
+ * we need to move it.
+ *
+ * @returns true if not and it should be resorted.
+ */
+bool nsNavHistoryContainerResultNode::DoesChildNeedResorting(
+    int32_t aIndex, SortComparator aComparator) {
+  MOZ_ASSERT(aIndex < mChildren.Count(), "Input index out of range");
+  MOZ_ASSERT(aIndex >= 0, "Input index out of range");
+  if (aIndex < 0 || aIndex >= mChildren.Count() || mChildren.Count() == 1) {
+    return false;
+  }
+
+  if (aIndex > 0) {
+    // compare to previous item
+    if (aComparator(mChildren[aIndex - 1], mChildren[aIndex]) > 0) {
+      return true;
+    }
+  }
+  if (aIndex < mChildren.Count() - 1) {
+    // compare to next item
+    if (aComparator(mChildren[aIndex], mChildren[aIndex + 1]) > 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/* static */
+int32_t nsNavHistoryContainerResultNode::SortComparison_StringLess(
+    const nsAString& a, const nsAString& b) {
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, 0);
+  const mozilla::intl::Collator* collator = history->GetCollator();
+  NS_ENSURE_TRUE(collator, 0);
+
+  int32_t res = collator->CompareStrings(a, b);
+  return res;
+}
+
+/**
+ * When there are bookmark indices, we should never have ties, so we don't
+ * need to worry about tiebreaking.  When there are no bookmark indices,
+ * everything will be -1 and we don't worry about sorting.
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_Bookmark(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return a->mBookmarkIndex - b->mBookmarkIndex;
+}
+
+/**
+ * These are a little more complicated because they do a localization
+ * conversion.  If this is too slow, we can compute the sort keys once in
+ * advance, sort that array, and then reorder the real array accordingly.
+ * This would save some key generations.
+ *
+ * The collation object must be allocated before sorting on title!
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_TitleLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  uint32_t aType;
+  a->GetType(&aType);
+
+  int32_t value = SortComparison_StringLess(NS_ConvertUTF8toUTF16(a->mTitle),
+                                            NS_ConvertUTF8toUTF16(b->mTitle));
+  if (value == 0) {
+    // resolve by URI
+    if (a->IsURI()) {
+      value = Compare(a->mURI, b->mURI);
+    }
+    if (value == 0) {
+      // resolve by date
+      value = ComparePRTime(a->mTime, b->mTime);
+      if (value == 0) {
+        value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+      }
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_TitleGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -SortComparison_TitleLess(a, b);
+}
+
+/**
+ * Equal times will be very unusual, but it is important that there is some
+ * deterministic ordering of the results so they don't move around.
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_DateLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = ComparePRTime(a->mTime, b->mTime);
+  if (value == 0) {
+    value = SortComparison_StringLess(NS_ConvertUTF8toUTF16(a->mTitle),
+                                      NS_ConvertUTF8toUTF16(b->mTitle));
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_DateGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -nsNavHistoryContainerResultNode::SortComparison_DateLess(a, b);
+}
+
+int32_t nsNavHistoryContainerResultNode::SortComparison_DateAddedLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = ComparePRTime(a->mDateAdded, b->mDateAdded);
+  if (value == 0) {
+    value = SortComparison_StringLess(NS_ConvertUTF8toUTF16(a->mTitle),
+                                      NS_ConvertUTF8toUTF16(b->mTitle));
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_DateAddedGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -nsNavHistoryContainerResultNode::SortComparison_DateAddedLess(a, b);
+}
+
+int32_t nsNavHistoryContainerResultNode::SortComparison_LastModifiedLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = ComparePRTime(a->mLastModified, b->mLastModified);
+  if (value == 0) {
+    value = SortComparison_StringLess(NS_ConvertUTF8toUTF16(a->mTitle),
+                                      NS_ConvertUTF8toUTF16(b->mTitle));
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_LastModifiedGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -nsNavHistoryContainerResultNode::SortComparison_LastModifiedLess(a,
+                                                                           b);
+}
+
+/**
+ * Certain types of parent nodes are treated specially because URIs are not
+ * valid (like days or hosts).
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_URILess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value;
+  if (a->IsURI() && b->IsURI()) {
+    // normal URI or visit
+    value = Compare(a->mURI, b->mURI);
+  } else if (a->IsContainer() && !b->IsContainer()) {
+    // Containers appear before entries with a uri.
+    return -1;
+  } else if (b->IsContainer() && !a->IsContainer()) {
+    return 1;
+  } else {
+    // For everything else, use title sorting.
+    value = SortComparison_StringLess(NS_ConvertUTF8toUTF16(a->mTitle),
+                                      NS_ConvertUTF8toUTF16(b->mTitle));
+  }
+
+  if (value == 0) {
+    value = ComparePRTime(a->mTime, b->mTime);
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_URIGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -SortComparison_URILess(a, b);
+}
+
+/**
+ * Fall back on dates for conflict resolution
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_VisitCountLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = CompareIntegers(a->mAccessCount, b->mAccessCount);
+  if (value == 0) {
+    value = ComparePRTime(a->mTime, b->mTime);
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_VisitCountGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -nsNavHistoryContainerResultNode::SortComparison_VisitCountLess(a, b);
+}
+
+int32_t nsNavHistoryContainerResultNode::SortComparison_TagsLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = 0;
+  nsAutoString aTags, bTags;
+
+  nsresult rv = a->GetTags(aTags);
+  NS_ENSURE_SUCCESS(rv, 0);
+
+  rv = b->GetTags(bTags);
+  NS_ENSURE_SUCCESS(rv, 0);
+
+  value = SortComparison_StringLess(aTags, bTags);
+
+  // fall back to title sorting
+  if (value == 0) {
+    value = SortComparison_TitleLess(a, b);
+  }
+
+  return value;
+}
+
+int32_t nsNavHistoryContainerResultNode::SortComparison_TagsGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -SortComparison_TagsLess(a, b);
+}
+
+/**
+ * Fall back on date and bookmarked status, for conflict resolution.
+ */
+int32_t nsNavHistoryContainerResultNode::SortComparison_FrecencyLess(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  int32_t value = CompareIntegers(a->mFrecency, b->mFrecency);
+  if (value == 0) {
+    value = ComparePRTime(a->mTime, b->mTime);
+    if (value == 0) {
+      value = nsNavHistoryContainerResultNode::SortComparison_Bookmark(a, b);
+    }
+  }
+  return value;
+}
+int32_t nsNavHistoryContainerResultNode::SortComparison_FrecencyGreater(
+    nsNavHistoryResultNode* a, nsNavHistoryResultNode* b) {
+  return -nsNavHistoryContainerResultNode::SortComparison_FrecencyLess(a, b);
+}
+
+/**
+ * Searches this folder for a node with the given URI.  Returns null if not
+ * found.
+ *
+ * @note Does not addref the node!
+ */
+nsNavHistoryResultNode* nsNavHistoryContainerResultNode::FindChildByURI(
+    const nsACString& aSpec, uint32_t* aNodeIndex) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    if (mChildren[i]->IsURI()) {
+      if (aSpec.Equals(mChildren[i]->mURI)) {
+        *aNodeIndex = i;
+        return mChildren[i];
+      }
+    }
+  }
+  return nullptr;
+}
+
+/**
+ * Searches for matches for the given URI.
+ */
+void nsNavHistoryContainerResultNode::FindChildrenByURI(
+    const nsCString& aSpec, nsCOMArray<nsNavHistoryResultNode>* aMatches) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    if (mChildren[i]->IsURI()) {
+      if (aSpec.Equals(mChildren[i]->mURI)) {
+        aMatches->AppendObject(mChildren[i]);
+      }
+    }
+  }
+}
+
+/**
+ * Searches this folder for a node with the given guid/target-folder-guid.
+ *
+ * @return the node if found, null otherwise.
+ * @note Does not addref the node!
+ */
+nsNavHistoryResultNode* nsNavHistoryContainerResultNode::FindChildByGuid(
+    const nsACString& guid, int32_t* nodeIndex) {
+  *nodeIndex = -1;
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    if (mChildren[i]->mBookmarkGuid == guid ||
+        mChildren[i]->mPageGuid == guid ||
+        (mChildren[i]->IsFolder() &&
+         mChildren[i]->GetAsFolder()->mTargetFolderGuid == guid)) {
+      *nodeIndex = i;
+      return mChildren[i];
+    }
+  }
+  return nullptr;
+}
+
+/**
+ * Searches this folder for a node with the given id/target-folder-id.
+ *
+ * @return the node if found, null otherwise.
+ * @note Does not addref the node!
+ */
+nsNavHistoryResultNode* nsNavHistoryContainerResultNode::FindChildById(
+    int64_t aItemId, int32_t* aNodeIndex) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    if (mChildren[i]->mItemId == aItemId ||
+        (mChildren[i]->IsFolder() &&
+         mChildren[i]->GetAsFolder()->mTargetFolderItemId == aItemId)) {
+      *aNodeIndex = i;
+      return mChildren[i];
+    }
+  }
+  *aNodeIndex = -1;
+  return nullptr;
+}
+
+/**
+ * This does the work of adding a child to the container.  The child can be
+ * either a container or or a single item that may even be collapsed with the
+ * adjacent ones.
+ */
+nsresult nsNavHistoryContainerResultNode::InsertChildAt(
+    nsNavHistoryResultNode* aNode, int32_t aIndex) {
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+
+  SetAsParentOfNode(aNode);
+
+  if (!mChildren.InsertObjectAt(aNode, aIndex)) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Update our stats and notify the result's observers.
+  uint32_t oldAccessCount = mAccessCount;
+  PRTime oldTime = mTime;
+
+  mAccessCount += aNode->mAccessCount;
+  if (mTime < aNode->mTime) {
+    mTime = aNode->mTime;
+  }
+  if ((!mParent || mParent->AreChildrenVisible()) &&
+      !result->CanSkipHistoryDetailsNotifications()) {
+    NOTIFY_RESULT_OBSERVERS(
+        result, NodeHistoryDetailsChanged(TO_ICONTAINER(this), oldTime,
+                                          oldAccessCount));
+  }
+
+  nsresult rv = ReverseUpdateStats(static_cast<int32_t>(aNode->mAccessCount));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Update tree if we are visible.  Note that we could be here and not
+  // expanded, like when there is a bookmark folder being updated because its
+  // parent is visible.
+  if (AreChildrenVisible()) {
+    NOTIFY_RESULT_OBSERVERS(result, NodeInserted(this, aNode, aIndex));
+  }
+
+  return NS_OK;
+}
+
+/**
+ * This locates the proper place for insertion according to the current sort
+ * and calls InsertChildAt
+ */
+nsresult nsNavHistoryContainerResultNode::InsertSortedChild(
+    nsNavHistoryResultNode* aNode, bool aIgnoreDuplicates) {
+  if (mChildren.Count() == 0) return InsertChildAt(aNode, 0);
+
+  SortComparator comparator = GetSortingComparator(GetSortType());
+  if (comparator) {
+    // When inserting a new node, it must have proper statistics because we use
+    // them to find the correct insertion point.  The insert function will then
+    // recompute these statistics and fill in the proper parents and hierarchy
+    // level.  Doing this twice shouldn't be a large performance penalty because
+    // when we are inserting new containers, they typically contain only one
+    // item (because we've browsed a new page).
+    if (aNode->IsContainer()) {
+      // need to update all the new item's children
+      nsNavHistoryContainerResultNode* container = aNode->GetAsContainer();
+      container->mResult = mResult;
+      container->FillStats();
+    }
+
+    bool itemExists;
+    int32_t position = FindInsertionPoint(aNode, comparator, &itemExists);
+    if (aIgnoreDuplicates && itemExists) {
+      return NS_OK;
+    }
+
+    return InsertChildAt(aNode, position);
+  }
+  return InsertChildAt(aNode, mChildren.Count());
+}
+
+/**
+ * This checks if the item at aIndex is located correctly given the sorting
+ * move.  If it's not, the item is moved, and the result's observers are
+ * notified.
+ *
+ * @return true if the item position has been changed, false otherwise.
+ */
+bool nsNavHistoryContainerResultNode::EnsureItemPosition(int32_t aIndex) {
+  NS_ASSERTION(aIndex < mChildren.Count(), "Invalid index");
+  if (aIndex >= mChildren.Count()) {
+    return false;
+  }
+
+  SortComparator comparator = GetSortingComparator(GetSortType());
+  if (!comparator) {
+    return false;
+  }
+
+  if (!DoesChildNeedResorting(aIndex, comparator)) {
+    return false;
+  }
+
+  RefPtr<nsNavHistoryResultNode> node(mChildren[aIndex]);
+  mChildren.RemoveObjectAt(aIndex);
+
+  int32_t newIndex = FindInsertionPoint(node, comparator, nullptr);
+  mChildren.InsertObjectAt(node.get(), newIndex);
+
+  if (AreChildrenVisible()) {
+    nsNavHistoryResult* result = GetResult();
+    NOTIFY_RESULT_OBSERVERS_RET(
+        result, NodeMoved(node, this, aIndex, this, newIndex), false);
+  }
+
+  return true;
+}
+
+/**
+ * This does all the work of removing a child from this container, including
+ * updating the tree if necessary.  Note that we do not need to be open for
+ * this to work.
+ */
+nsresult nsNavHistoryContainerResultNode::RemoveChildAt(int32_t aIndex) {
+  NS_ASSERTION(aIndex >= 0 && aIndex < mChildren.Count(), "Invalid index");
+
+  // Hold an owning reference to keep from expiring while we work with it.
+  RefPtr<nsNavHistoryResultNode> oldNode = mChildren[aIndex];
+
+  // Update stats.
+  // XXX This assertion does not reliably pass -- investigate!! (bug 1049797)
+  // MOZ_ASSERT(mAccessCount >= mChildren[aIndex]->mAccessCount,
+  //            "Invalid access count while updating!");
+  uint32_t oldAccessCount = mAccessCount;
+  mAccessCount -= mChildren[aIndex]->mAccessCount;
+
+  // Remove it from our list and notify the result's observers.
+  mChildren.RemoveObjectAt(aIndex);
+  if (AreChildrenVisible()) {
+    nsNavHistoryResult* result = GetResult();
+    NOTIFY_RESULT_OBSERVERS(result, NodeRemoved(this, oldNode, aIndex));
+  }
+
+  nsresult rv = ReverseUpdateStats(static_cast<int32_t>(mAccessCount) -
+                                   static_cast<int32_t>(oldAccessCount));
+  NS_ENSURE_SUCCESS(rv, rv);
+  oldNode->OnRemoving();
+  return NS_OK;
+}
+
+/**
+ * Searches for matches for the given URI.  If aOnlyOne is set, it will
+ * terminate as soon as it finds a single match.  This would be used when there
+ * are URI results so there will only ever be one copy of any URI.
+ *
+ * When aOnlyOne is false, it will check all elements.  This is for non-history
+ * or visit style results that may have multiple copies of any given URI.
+ */
+void nsNavHistoryContainerResultNode::RecursiveFindURIs(
+    bool aOnlyOne, nsNavHistoryContainerResultNode* aContainer,
+    const nsCString& aSpec, nsCOMArray<nsNavHistoryResultNode>* aMatches) {
+  for (int32_t i = 0; i < aContainer->mChildren.Count(); ++i) {
+    auto* node = aContainer->mChildren[i];
+    if (node->IsURI()) {
+      if (node->mURI.Equals(aSpec)) {
+        aMatches->AppendObject(node);
+        if (aOnlyOne) {
+          return;
+        }
+      }
+    } else if (node->IsContainer() && node->GetAsContainer()->mExpanded) {
+      RecursiveFindURIs(aOnlyOne, node->GetAsContainer(), aSpec, aMatches);
+    }
+  }
+}
+
+/**
+ * If aUpdateSort is true, we will also update the sorting of this item.
+ * Normally you want this to be true, but it can be false if the thing you are
+ * changing can not affect sorting (like favicons).
+ *
+ * You should NOT change any child lists as part of the callback function.
+ */
+bool nsNavHistoryContainerResultNode::UpdateURIs(
+    bool aRecursive, bool aOnlyOne, bool aUpdateSort, const nsCString& aSpec,
+    nsresult (*aCallback)(nsNavHistoryResultNode*, const void*,
+                          const nsNavHistoryResult*),
+    const void* aClosure) {
+  const nsNavHistoryResult* result = GetResult();
+  if (!result) {
+    MOZ_ASSERT(false, "Should have a result");
+    return false;
+  }
+
+  // this needs to be owning since sometimes we remove and re-insert nodes
+  // in their parents and we don't want them to go away.
+  nsCOMArray<nsNavHistoryResultNode> matches;
+
+  if (aRecursive) {
+    RecursiveFindURIs(aOnlyOne, this, aSpec, &matches);
+  } else if (aOnlyOne) {
+    uint32_t nodeIndex;
+    nsNavHistoryResultNode* node = FindChildByURI(aSpec, &nodeIndex);
+    if (node) {
+      matches.AppendObject(node);
+    }
+  } else {
+    MOZ_ASSERT(
+        false,
+        "UpdateURIs does not handle nonrecursive updates of multiple items.");
+    // this case easy to add if you need it, just find all the matching URIs
+    // at this level.  However, this isn't currently used. History uses
+    // recursive, Bookmarks uses one level and knows that the match is unique.
+    return false;
+  }
+
+  if (matches.Count() == 0) return false;
+
+  // PERFORMANCE: This updates each container for each child in it that
+  // changes.  In some cases, many elements have changed inside the same
+  // container.  It would be better to compose a list of containers, and
+  // update each one only once for all the items that have changed in it.
+  for (int32_t i = 0; i < matches.Count(); ++i) {
+    nsNavHistoryResultNode* node = matches[i];
+    nsNavHistoryContainerResultNode* parent = node->mParent;
+    if (!parent) {
+      MOZ_ASSERT(false, "All URI nodes being updated must have parents");
+      continue;
+    }
+
+    uint32_t oldAccessCount = node->mAccessCount;
+    PRTime oldTime = node->mTime;
+    uint32_t parentOldAccessCount = parent->mAccessCount;
+    PRTime parentOldTime = parent->mTime;
+
+    aCallback(node, aClosure, result);
+
+    if (oldAccessCount != node->mAccessCount || oldTime != node->mTime) {
+      parent->mAccessCount += node->mAccessCount - oldAccessCount;
+      if (node->mTime > parent->mTime) {
+        parent->mTime = node->mTime;
+      }
+      if (parent->AreChildrenVisible() &&
+          !result->CanSkipHistoryDetailsNotifications()) {
+        NOTIFY_RESULT_OBSERVERS_RET(
+            result,
+            NodeHistoryDetailsChanged(TO_ICONTAINER(parent), parentOldTime,
+                                      parentOldAccessCount),
+            true);
+      }
+      DebugOnly<nsresult> rv =
+          parent->ReverseUpdateStats(static_cast<int32_t>(node->mAccessCount) -
+                                     static_cast<int32_t>(oldAccessCount));
+      MOZ_ASSERT(NS_SUCCEEDED(rv), "should be able to ReverseUpdateStats");
+    }
+
+    if (aUpdateSort) {
+      int32_t childIndex = parent->FindChild(node);
+      MOZ_ASSERT(childIndex >= 0,
+                 "Could not find child we just got a reference to");
+      if (childIndex >= 0) {
+        parent->EnsureItemPosition(childIndex);
+      }
+    }
+  }
+
+  return true;
+}
+
+/**
+ * This is used to update the titles in the tree.  This is called from both
+ * query and bookmark folder containers to update the tree.  Bookmark folders
+ * should be sure to set recursive to false, since child folders will have
+ * their own callbacks registered.
+ */
+static nsresult setTitleCallback(nsNavHistoryResultNode* aNode,
+                                 const void* aClosure,
+                                 const nsNavHistoryResult* aResult) {
+  const nsACString* newTitle = static_cast<const nsACString*>(aClosure);
+  aNode->mTitle = *newTitle;
+
+  if (aResult && (!aNode->mParent || aNode->mParent->AreChildrenVisible())) {
+    NOTIFY_RESULT_OBSERVERS(aResult, NodeTitleChanged(aNode, *newTitle));
+  }
+
+  return NS_OK;
+}
+nsresult nsNavHistoryContainerResultNode::ChangeTitles(
+    nsIURI* aURI, const nsACString& aNewTitle, bool aRecursive, bool aOnlyOne) {
+  // uri string
+  nsAutoCString uriString;
+  nsresult rv = aURI->GetSpec(uriString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // The recursive function will update the result's tree nodes, but only if we
+  // give it a non-null pointer.  So if there isn't a tree, just pass nullptr
+  // so it doesn't bother trying to call the result.
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+
+  uint16_t sortType = GetSortType();
+  bool updateSorting =
+      (sortType == nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING ||
+       sortType == nsINavHistoryQueryOptions::SORT_BY_TITLE_DESCENDING);
+
+  UpdateURIs(aRecursive, aOnlyOne, updateSorting, uriString, setTitleCallback,
+             static_cast<const void*>(&aNewTitle));
+
+  return NS_OK;
+}
+
+/**
+ * Complex containers (folders and queries) will override this.  Here, we
+ * handle the case of simple containers (like host groups) where the children
+ * are always stored.
+ */
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetHasChildren(bool* aHasChildren) {
+  *aHasChildren = (mChildren.Count() > 0);
+  return NS_OK;
+}
+
+/**
+ * @throws if this node is closed.
+ */
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetChildCount(uint32_t* aChildCount) {
+  if (!mExpanded) return NS_ERROR_NOT_AVAILABLE;
+  *aChildCount = mChildren.Count();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetChild(uint32_t aIndex,
+                                          nsINavHistoryResultNode** _child) {
+  if (!mExpanded) return NS_ERROR_NOT_AVAILABLE;
+  if (aIndex >= mChildren.Length()) return NS_ERROR_INVALID_ARG;
+  nsCOMPtr<nsINavHistoryResultNode> child = mChildren.ElementAt(aIndex);
+  child.forget(_child);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryContainerResultNode::GetChildIndex(nsINavHistoryResultNode* aNode,
+                                               uint32_t* _retval) {
+  if (!mExpanded) return NS_ERROR_NOT_AVAILABLE;
+
+  int32_t nodeIndex = FindChild(static_cast<nsNavHistoryResultNode*>(aNode));
+  if (nodeIndex == -1) return NS_ERROR_INVALID_ARG;
+
+  *_retval = nodeIndex;
+  return NS_OK;
+}
+
+/**
+ * HOW QUERY UPDATING WORKS
+ *
+ * Queries are different than bookmark folders in that we can not always do
+ * dynamic updates (easily) and updates are more expensive.  Therefore, we do
+ * NOT query if we are not open and want to see if we have any children (for
+ * drawing a twisty) and always assume we will.
+ *
+ * When the container is opened, we execute the query and register the
+ * listeners.  Like bookmark folders, we stay registered even when closed, and
+ * clear ourselves as soon as a message comes in.  This lets us respond quickly
+ * if the user closes and reopens the container.
+ *
+ * We try to handle the most common notifications for the most common query
+ * types dynamically, that is, figuring out what should happen in response to
+ * a message without doing a requery.  For complex changes or complex queries,
+ * we give up and requery.
+ */
+NS_IMPL_ISUPPORTS_INHERITED(nsNavHistoryQueryResultNode,
+                            nsNavHistoryContainerResultNode,
+                            nsINavHistoryQueryResultNode)
+
+nsNavHistoryQueryResultNode::nsNavHistoryQueryResultNode(
+    const nsACString& aTitle, PRTime aTime, const nsACString& aQueryURI,
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions)
+    : nsNavHistoryContainerResultNode(aQueryURI, aTitle, aTime,
+                                      nsNavHistoryResultNode::RESULT_TYPE_QUERY,
+                                      aOptions),
+      mQuery(aQuery),
+      mHasSearchTerms(false),
+      mLiveUpdate(getUpdateRequirements(aQuery, aOptions, &mHasSearchTerms)),
+      mContentsValid(false),
+      mBatchChanges(0),
+      mTransitions(aQuery->Transitions().Clone()) {}
+
+nsNavHistoryQueryResultNode::~nsNavHistoryQueryResultNode() {
+  // Remove this node from result's observers.  We don't need to be notified
+  // anymore.
+  if (mResult && mResult->mAllBookmarksObservers.Contains(this)) {
+    mResult->RemoveAllBookmarksObserver(this);
+  }
+  if (mResult && mResult->mHistoryObservers.Contains(this)) {
+    mResult->RemoveHistoryObserver(this);
+  }
+  if (mResult && mResult->mMobilePrefObservers.Contains(this)) {
+    mResult->RemoveMobilePrefsObserver(this);
+  }
+}
+
+/**
+ * Whoever made us may want non-expanding queries. However, we always expand
+ * when we are the root node, or else asking for non-expanding queries would be
+ * useless.  A query node is not expandable if excludeItems is set or if
+ * expandQueries is unset.
+ */
+bool nsNavHistoryQueryResultNode::CanExpand() {
+  // The root node and containersQueries can always expand;
+  if ((mResult && mResult->mRootNode == this) || IsContainersQuery()) {
+    return true;
+  }
+
+  if (mOptions->ExcludeItems()) {
+    return false;
+  }
+  if (mOptions->ExpandQueries()) {
+    return true;
+  }
+
+  return false;
+}
+
+/**
+ * Some query with a particular result type can contain other queries.  They
+ * must be always expandable
+ */
+bool nsNavHistoryQueryResultNode::IsContainersQuery() {
+  uint16_t resultType = Options()->ResultType();
+  return resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY ||
+         resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY ||
+         resultType == nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT ||
+         resultType == nsINavHistoryQueryOptions::RESULTS_AS_SITE_QUERY ||
+         resultType == nsINavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY ||
+         resultType == nsINavHistoryQueryOptions::RESULTS_AS_LEFT_PANE_QUERY;
+}
+
+/**
+ * Here we do not want to call ContainerResultNode::OnRemoving since our own
+ * ClearChildren will do the same thing and more (unregister the observers).
+ * The base ResultNode::OnRemoving will clear some regular node stats, so it is
+ * OK.
+ */
+void nsNavHistoryQueryResultNode::OnRemoving() {
+  nsNavHistoryResultNode::OnRemoving();
+  ClearChildren(true);
+  mResult = nullptr;
+}
+
+/**
+ * Marks the container as open, rebuilding results if they are invalid.  We
+ * may still have valid results if the container was previously open and
+ * nothing happened since closing it.
+ *
+ * We do not handle CloseContainer specially.  The default one just marks the
+ * container as closed, but doesn't actually mark the results as invalid.
+ * The results will be invalidated by the next history or bookmark
+ * notification that comes in.  This means if you open and close the item
+ * without anything happening in between, it will be fast (this actually
+ * happens when results are used as menus).
+ */
+nsresult nsNavHistoryQueryResultNode::OpenContainer() {
+  NS_ASSERTION(!mExpanded, "Container must be closed to open it");
+  mExpanded = true;
+
+  nsresult rv;
+
+  if (!CanExpand()) return NS_OK;
+  if (!mContentsValid) {
+    rv = FillChildren();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  rv = NotifyOnStateChange(STATE_CLOSED);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+/**
+ * When we have valid results we can always give an exact answer.  When we
+ * don't we just assume we'll have results, since actually doing the query
+ * might be hard.  This is used to draw twisties on the tree, so precise results
+ * don't matter.
+ */
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetHasChildren(bool* aHasChildren) {
+  *aHasChildren = false;
+
+  if (!CanExpand()) {
+    return NS_OK;
+  }
+
+  uint16_t resultType = mOptions->ResultType();
+
+  // Tags are always populated, otherwise they are removed.
+  if (mQuery->Tags().Length() == 1 && mParent &&
+      mParent->mOptions->ResultType() ==
+          nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT) {
+    *aHasChildren = true;
+    return NS_OK;
+  }
+
+  // AllBookmarks and the left pane folder also always have children.
+  if (resultType == nsINavHistoryQueryOptions::RESULTS_AS_ROOTS_QUERY ||
+      resultType == nsINavHistoryQueryOptions::RESULTS_AS_LEFT_PANE_QUERY) {
+    *aHasChildren = true;
+    return NS_OK;
+  }
+
+  // For history containers query we must check if we have any history
+  if (resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY ||
+      resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY ||
+      resultType == nsINavHistoryQueryOptions::RESULTS_AS_SITE_QUERY) {
+    nsNavHistory* history = nsNavHistory::GetHistoryService();
+    NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+    *aHasChildren = history->hasHistoryEntries();
+    return NS_OK;
+  }
+
+  // TODO (Bug 1477934): We don't have a good synchronous way to fetch whether
+  // we have tags or not, to properly reply to the hasChildren request on the
+  // tags root. Potentially we could pass this information when we create the
+  // container.
+
+  // If the container is open and populated, this is trivial.
+  if (mContentsValid) {
+    *aHasChildren = (mChildren.Count() > 0);
+    return NS_OK;
+  }
+
+  // Fallback to assume we have children.
+  *aHasChildren = true;
+  return NS_OK;
+}
+
+/**
+ * This doesn't just return mURI because in the case of queries that may
+ * be lazily constructed from the query objects.
+ */
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetUri(nsACString& aURI) {
+  aURI = mURI;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetFolderItemId(int64_t* aItemId) {
+  *aItemId = -1;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetTargetFolderGuid(nsACString& aGuid) {
+  aGuid.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetQuery(nsINavHistoryQuery** _query) {
+  RefPtr<nsNavHistoryQuery> query = mQuery;
+  query.forget(_query);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryQueryResultNode::GetQueryOptions(
+    nsINavHistoryQueryOptions** _options) {
+  MOZ_ASSERT(mOptions, "Options should be valid");
+  RefPtr<nsNavHistoryQueryOptions> options = mOptions;
+  options.forget(_options);
+  return NS_OK;
+}
+
+/**
+ * Safe options getter, ensures query is parsed first.
+ */
+nsNavHistoryQueryOptions* nsNavHistoryQueryResultNode::Options() {
+  MOZ_ASSERT(mOptions, "Options invalid, cannot generate from URI");
+  return mOptions;
+}
+
+nsresult nsNavHistoryQueryResultNode::FillChildren() {
+  MOZ_ASSERT(!mContentsValid,
+             "Don't call FillChildren when contents are valid");
+  MOZ_ASSERT(mChildren.Count() == 0,
+             "We are trying to fill children when there already are some");
+  NS_ENSURE_STATE(mQuery && mOptions);
+
+  // get the results from the history service
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+  nsresult rv = history->GetQueryResults(this, mQuery, mOptions, &mChildren);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // it is important to call FillStats to fill in the parents on all
+  // nodes and the result node pointers on the containers
+  FillStats();
+
+  uint16_t sortType = GetSortType();
+
+  if (mResult && mResult->mNeedsToApplySortingMode) {
+    // We should repopulate container and then apply sortingMode.  To avoid
+    // sorting 2 times we simply do that here.
+    mResult->SetSortingMode(mResult->mSortingMode);
+  } else if (mOptions->QueryType() !=
+                 nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY ||
+             sortType != nsINavHistoryQueryOptions::SORT_BY_NONE) {
+    // The default SORT_BY_NONE sorts by the bookmark index (position),
+    // which we do not have for history queries.
+    // Once we've computed all tree stats, we can sort, because containers will
+    // then have proper visit counts and dates.
+    SortComparator comparator = GetSortingComparator(GetSortType());
+    if (comparator) {
+      // Usually containers queries results comes already sorted from the
+      // database, but some locales could have special rules to sort by title.
+      // RecursiveSort won't apply these rules to containers in containers
+      // queries because when setting sortingMode on the result we want to sort
+      // contained items (bug 473157).
+      // Base container RecursiveSort will sort both our children and all
+      // descendants, and is used in this case because we have to do manual
+      // title sorting.
+      // Query RecursiveSort will instead only sort descendants if we are a
+      // constinaersQuery, e.g. a grouped query that will return other queries.
+      // For other type of queries it will act as the base one.
+      if (IsContainersQuery() && sortType == mOptions->SortingMode() &&
+          (sortType == nsINavHistoryQueryOptions::SORT_BY_TITLE_ASCENDING ||
+           sortType == nsINavHistoryQueryOptions::SORT_BY_TITLE_DESCENDING)) {
+        nsNavHistoryContainerResultNode::RecursiveSort(comparator);
+      } else {
+        RecursiveSort(comparator);
+      }
+    }
+  }
+
+  // if we are limiting our results remove items from the end of the
+  // mChildren array after sorting. This is done for root node only.
+  // note, if count < max results, we won't do anything.
+  if (!mParent && mOptions->MaxResults()) {
+    while (mChildren.Length() > mOptions->MaxResults()) {
+      mChildren.RemoveObjectAt(mChildren.Count() - 1);
+    }
+  }
+
+  // If we're not updating the query, we don't need to add listeners, so bail
+  // out early.
+  if (mLiveUpdate == QUERYUPDATE_NONE) {
+    mContentsValid = true;
+    return NS_OK;
+  }
+
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+
+  // Ensure to add history observer before bookmarks observer, because the
+  // latter wants to know if an history observer was added.
+
+  if (mOptions->QueryType() == nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY) {
+    // Date containers that contain site containers have no reason to observe
+    // history, if the inside site container is expanded it will update,
+    // otherwise we are going to refresh the parent query.
+    if (!mParent || mParent->mOptions->ResultType() !=
+                        nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY) {
+      // register with the result for history updates
+      result->AddHistoryObserver(this);
+    }
+  }
+
+  if (mOptions->QueryType() ==
+          nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS ||
+      mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS || mHasSearchTerms) {
+    // register with the result for bookmark updates
+    result->AddAllBookmarksObserver(this);
+  }
+
+  if (mLiveUpdate == QUERYUPDATE_MOBILEPREF) {
+    result->AddMobilePrefsObserver(this);
+  }
+
+  mContentsValid = true;
+  return NS_OK;
+}
+
+/**
+ * Call with unregister = false when we are going to update the children (for
+ * example, when the container is open).  This will clear the list and notify
+ * all the children that they are going away.
+ *
+ * When the results are becoming invalid and we are not going to refresh them,
+ * set unregister = true, which will unregister the listener from the
+ * result if any.  We use unregister = false when we are refreshing the list
+ * immediately so want to stay a notifier.
+ */
+void nsNavHistoryQueryResultNode::ClearChildren(bool aUnregister) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) mChildren[i]->OnRemoving();
+  mChildren.Clear();
+
+  if (aUnregister && mContentsValid) {
+    nsNavHistoryResult* result = GetResult();
+    if (result) {
+      result->RemoveHistoryObserver(this);
+      result->RemoveAllBookmarksObserver(this);
+      result->RemoveMobilePrefsObserver(this);
+    }
+  }
+  mContentsValid = false;
+}
+
+/**
+ * This is called to update the result when something has changed that we
+ * can not incrementally update.
+ */
+nsresult nsNavHistoryQueryResultNode::Refresh() {
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->IsBatching()) {
+    result->requestRefresh(this);
+    return NS_OK;
+  }
+
+  // This is not a root node but it does not have a parent - this means that
+  // the node has already been cleared and it is now called, because it was
+  // left in a local copy of the observers array.
+  if (mIndentLevel > -1 && !mParent) return NS_OK;
+
+  // Do not refresh if we are not expanded or if we are child of a query
+  // containing other queries.  In this case calling Refresh for each child
+  // query could cause a major slowdown.  We should not refresh nested
+  // queries, since we will already refresh the parent one.
+  // The only exception to this, is if the parent query is of QUERYUPDATE_NONE,
+  // this can be the case for the RESULTS_AS_TAGS_ROOT
+  // under RESULTS_AS_LEFT_PANE_QUERY.
+  if (!mExpanded) {
+    ClearChildren(true);
+    return NS_OK;
+  }
+
+  if (mParent && mParent->IsQuery()) {
+    nsNavHistoryQueryResultNode* parent = mParent->GetAsQuery();
+    if (parent->IsContainersQuery() &&
+        parent->mLiveUpdate != QUERYUPDATE_NONE) {
+      // Don't update, just invalidate and unhook
+      ClearChildren(true);
+      return NS_OK;  // no updates in tree state
+    }
+  }
+
+  if (mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS) {
+    ClearChildren(true);
+  } else {
+    ClearChildren(false);
+  }
+
+  // Ignore errors from FillChildren, since we will still want to refresh
+  // the tree (there just might not be anything in it on error).
+  (void)FillChildren();
+
+  NOTIFY_RESULT_OBSERVERS(result, InvalidateContainer(TO_CONTAINER(this)));
+  return NS_OK;
+}
+
+/**
+ * Here, we override GetSortType to return the current sorting for this
+ * query.  GetSortType is used when dynamically inserting query results so we
+ * can see which comparator we should use to find the proper insertion point
+ * (it shouldn't be called from folder containers which maintain their own
+ * sorting).
+ *
+ * Normally, the container just forwards it up the chain.  This is what we want
+ * for host groups, for example.  For queries, we often want to use the query's
+ * sorting mode.
+ *
+ * However, we only use this query node's sorting when it is not the root.
+ * When it is the root, we use the result's sorting mode.  This is because
+ * there are two cases:
+ *   - You are looking at a bookmark hierarchy that contains an embedded
+ *     result.  We should always use the query's sort ordering since the result
+ *     node's headers have nothing to do with us (and are disabled).
+ *   - You are looking at a query in the tree.  In this case, we want the
+ *     result sorting to override ours (it should be initialized to the same
+ *     sorting mode).
+ */
+uint16_t nsNavHistoryQueryResultNode::GetSortType() {
+  if (mParent) return mOptions->SortingMode();
+  if (mResult) return mResult->mSortingMode;
+
+  // This is a detached container, just use natural order.
+  return nsINavHistoryQueryOptions::SORT_BY_NONE;
+}
+
+void nsNavHistoryQueryResultNode::RecursiveSort(SortComparator aComparator) {
+  if (!IsContainersQuery()) {
+    mChildren.Sort(aComparator);
+  }
+
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    if (mChildren[i]->IsContainer()) {
+      mChildren[i]->GetAsContainer()->RecursiveSort(aComparator);
+    }
+  }
+}
+
+nsresult nsNavHistoryQueryResultNode::OnBeginUpdateBatch() { return NS_OK; }
+
+nsresult nsNavHistoryQueryResultNode::OnEndUpdateBatch() {
+  // If the query has no children it's possible it's not yet listening to
+  // bookmarks changes, in such a case it's safer to force a refresh to gather
+  // eventual new nodes matching query options.
+  if (mChildren.Count() == 0) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  mBatchChanges = 0;
+  return NS_OK;
+}
+
+static nsresult setHistoryDetailsCallback(nsNavHistoryResultNode* aNode,
+                                          const void* aClosure,
+                                          const nsNavHistoryResult* aResult) {
+  const nsNavHistoryResultNode* updatedNode =
+      static_cast<const nsNavHistoryResultNode*>(aClosure);
+
+  aNode->mAccessCount = updatedNode->mAccessCount;
+  if (aNode->mTime < updatedNode->mTime) {
+    aNode->mTime = updatedNode->mTime;
+  }
+  aNode->mFrecency = updatedNode->mFrecency;
+  aNode->mHidden = updatedNode->mHidden;
+
+  return NS_OK;
+}
+
+/**
+ * Here we need to update all copies of the URI we have with the new visit
+ * count, and potentially add a new entry in our query.  This is the most
+ * common update operation and it is important that it be as efficient as
+ * possible.
+ */
+nsresult nsNavHistoryQueryResultNode::OnVisit(
+    nsIURI* aURI, int64_t aVisitId, PRTime aTime, uint32_t aTransitionType,
+    const nsACString& aGUID, bool aHidden, uint32_t aVisitCount,
+    const nsAString& aLastKnownTitle, int64_t aFrecency, uint32_t* aAdded) {
+  // Skip the notification if the visit details are filtered out by the query.
+  if (!isQueryMatchingVisitDetails(mQuery, mOptions, aHidden, aTime,
+                                   aTransitionType, aURI)) {
+    return NS_OK;
+  }
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->IsBatching() &&
+      ++mBatchChanges > MAX_BATCH_CHANGES_BEFORE_REFRESH) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+    return NS_OK;
+  }
+
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+
+  switch (mLiveUpdate) {
+    case QUERYUPDATE_MOBILEPREF: {
+      return NS_OK;
+    }
+
+    case QUERYUPDATE_HOST: {
+      // For these simple yet common cases we can check the host ourselves
+      // before doing the overhead of creating a new result node.
+      if (mQuery->Domain().IsVoid()) return NS_OK;
+
+      nsAutoCString host;
+      if (NS_FAILED(aURI->GetAsciiHost(host))) return NS_OK;
+
+      if (!mQuery->Domain().Equals(host)) return NS_OK;
+
+      // Fall through to check the time, if the time is not present it will
+      // still match.
+      [[fallthrough]];
+    }
+
+    case QUERYUPDATE_TIME: {
+      // For these simple yet common cases we can check the time ourselves
+      // before doing the overhead of creating a new result node.
+      bool hasIt;
+      mQuery->GetHasBeginTime(&hasIt);
+      if (hasIt) {
+        PRTime beginTime = nsNavHistory::NormalizeTime(
+            mQuery->BeginTimeReference(), mQuery->BeginTime());
+        if (aTime < beginTime) return NS_OK;  // before our time range
+      }
+      mQuery->GetHasEndTime(&hasIt);
+      if (hasIt) {
+        PRTime endTime = nsNavHistory::NormalizeTime(mQuery->EndTimeReference(),
+                                                     mQuery->EndTime());
+        if (aTime > endTime) return NS_OK;  // after our time range
+      }
+      // Now we know that our visit satisfies the time range, fall through to
+      // the QUERYUPDATE_SIMPLE case below.
+      [[fallthrough]];
+    }
+
+    case QUERYUPDATE_SIMPLE: {
+      if (mOptions->ResultType() !=
+              nsNavHistoryQueryOptions::RESULTS_AS_VISIT &&
+          mOptions->ResultType() != nsNavHistoryQueryOptions::RESULTS_AS_URI) {
+        // Certain result types manage the nodes by themselves.
+        return NS_OK;
+      }
+
+      nsAutoCString spec;
+      nsresult rv = aURI->GetSpec(spec);
+      NS_ENSURE_SUCCESS(rv, rv);
+      RefPtr<nsNavHistoryResultNode> addition = new nsNavHistoryResultNode(
+          spec, NS_ConvertUTF16toUTF8(aLastKnownTitle), aVisitCount, aTime);
+      addition->mPageGuid.Assign(aGUID);
+      addition->mFrecency = aFrecency;
+      addition->mHidden = aHidden;
+      addition->mTransitionType = aTransitionType;
+
+      if (mOptions->ResultType() ==
+          nsNavHistoryQueryOptions::RESULTS_AS_VISIT) {
+        addition->mVisitId = aVisitId;
+      }
+
+      // Optimization for a common case: if the query has maxResults and is
+      // sorted by date, get the current boundaries and check if the added
+      // visit would fit. Later, we may have to remove the last child to
+      // respect maxResults.
+      if (mOptions->MaxResults() &&
+          mChildren.Length() >= mOptions->MaxResults()) {
+        uint16_t sortType = GetSortType();
+        if (sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING &&
+            aTime > std::max(mChildren[0]->mTime,
+                             mChildren[mChildren.Count() - 1]->mTime)) {
+          return NS_OK;
+        }
+        if (sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING &&
+            aTime < std::min(mChildren[0]->mTime,
+                             mChildren[mChildren.Count() - 1]->mTime)) {
+          return NS_OK;
+        }
+      }
+
+      if (mOptions->ResultType() ==
+          nsNavHistoryQueryOptions::RESULTS_AS_VISIT) {
+        // If this is a visit type query, just insert the new visit.  We never
+        // update visits, only add or remove them.
+        // If the query has search terms, ensure the new visit is matching them.
+        if (mHasSearchTerms && !isQuerySearchTermsMatching(mQuery, addition)) {
+          return NS_OK;
+        }
+        rv = InsertSortedChild(addition);
+        NS_ENSURE_SUCCESS(rv, rv);
+      } else {
+        uint16_t sortType = GetSortType();
+        bool updateSorting =
+            sortType ==
+                nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING ||
+            sortType ==
+                nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING ||
+            sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING ||
+            sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING ||
+            sortType == nsINavHistoryQueryOptions::SORT_BY_FRECENCY_ASCENDING ||
+            sortType == nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING;
+        if (!UpdateURIs(
+                false, true, updateSorting, addition->mURI,
+                setHistoryDetailsCallback,
+                const_cast<void*>(static_cast<void*>(addition.get())))) {
+          // Couldn't find a node to update, we may want to add one.
+          // If the query has search terms, ensure the new visit is matching
+          // them.
+          if (mHasSearchTerms &&
+              !isQuerySearchTermsMatching(mQuery, addition)) {
+            return NS_OK;
+          }
+          rv = InsertSortedChild(addition);
+          NS_ENSURE_SUCCESS(rv, rv);
+        }
+      }
+
+      // Trim the children if necessary.
+      if (mOptions->MaxResults() &&
+          mChildren.Length() > mOptions->MaxResults()) {
+        mChildren.RemoveObjectAt(mChildren.Count() - 1);
+      }
+
+      if (aAdded) {
+        ++(*aAdded);
+      }
+
+      break;
+    }
+
+    case QUERYUPDATE_COMPLEX:
+    case QUERYUPDATE_COMPLEX_WITH_BOOKMARKS:
+      // need to requery in complex cases
+      return Refresh();
+
+    default:
+      MOZ_ASSERT(false, "Invalid value for mLiveUpdate");
+      return Refresh();
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Find every node that matches this URI and rename it.  We try to do
+ * incremental updates here, even when we are closed, because changing titles
+ * is easier than requerying if we are invalid.
+ *
+ * This actually gets called a lot.  Typically, we will get an AddURI message
+ * when the user visits the page, and then the title will be set asynchronously
+ * when the title element of the page is parsed.
+ */
+nsresult nsNavHistoryQueryResultNode::OnTitleChanged(
+    nsIURI* aURI, const nsAString& aPageTitle, const nsACString& aGUID) {
+  if (!mExpanded) {
+    // When we are not expanded, we don't update, just invalidate and unhook.
+    // It would still be pretty easy to traverse the results and update the
+    // titles, but when a title changes, its unlikely that it will be the only
+    // thing.  Therefore, we just give up.
+    ClearChildren(true);
+    return NS_OK;  // no updates in tree state
+  }
+
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->IsBatching() &&
+      ++mBatchChanges > MAX_BATCH_CHANGES_BEFORE_REFRESH) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+    return NS_OK;
+  }
+
+  // compute what the new title should be
+  NS_ConvertUTF16toUTF8 newTitle(aPageTitle);
+
+  bool onlyOneEntry =
+      mOptions->ResultType() == nsINavHistoryQueryOptions::RESULTS_AS_URI;
+
+  // See if our query has any search term matching.
+  if (mHasSearchTerms) {
+    // Find all matching URI nodes.
+    nsCOMArray<nsNavHistoryResultNode> matches;
+    nsAutoCString spec;
+    nsresult rv = aURI->GetSpec(spec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    RecursiveFindURIs(onlyOneEntry, this, spec, &matches);
+
+    if (matches.Count() == 0) {
+      // If we didn't find any matching URI, and the query is filters by search
+      // terms, maybe the new title will match and then we want to Refresh()
+      // contents. Otherwise this will continue being an empty query.
+      return isQuerySearchTermsMatching(mQuery, mURI, newTitle, mTags)
+                 ? Refresh()
+                 : NS_OK;
+    }
+    for (int32_t i = 0; i < matches.Count(); ++i) {
+      // For each matched node we check if it passes the query filter, if not
+      // we remove the node from the result, otherwise we'll update the title
+      // later.
+      nsNavHistoryResultNode* node = matches[i];
+      // We must check the node with the new title.
+      node->mTitle = newTitle;
+
+      nsNavHistory* history = nsNavHistory::GetHistoryService();
+      NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+      if (!isQuerySearchTermsMatching(mQuery, node)) {
+        nsNavHistoryContainerResultNode* parent = node->mParent;
+        // URI nodes should always have parents
+        NS_ENSURE_TRUE(parent, NS_ERROR_UNEXPECTED);
+        int32_t childIndex = parent->FindChild(node);
+        NS_ASSERTION(childIndex >= 0, "Child not found in parent");
+        parent->RemoveChildAt(childIndex);
+      }
+    }
+  }
+
+  return ChangeTitles(aURI, newTitle, true, onlyOneEntry);
+}
+
+/**
+ * Here, we can always live update by just deleting all occurrences of
+ * the given URI.
+ */
+nsresult nsNavHistoryQueryResultNode::OnPageRemovedFromStore(
+    nsIURI* aURI, const nsACString& aGUID, uint16_t aReason) {
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->IsBatching() &&
+      ++mBatchChanges > MAX_BATCH_CHANGES_BEFORE_REFRESH) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+    return NS_OK;
+  }
+
+  if (IsContainersQuery()) {
+    // Incremental updates of query returning queries are pretty much
+    // complicated.  In this case it's possible one of the child queries has
+    // no more children and it should be removed.  Unfortunately there is no
+    // way to know that without executing the child query and counting results.
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+    return NS_OK;
+  }
+
+  bool onlyOneEntry =
+      mOptions->ResultType() == nsINavHistoryQueryOptions::RESULTS_AS_URI;
+
+  nsAutoCString spec;
+  nsresult rv = aURI->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMArray<nsNavHistoryResultNode> matches;
+  RecursiveFindURIs(onlyOneEntry, this, spec, &matches);
+  for (int32_t i = 0; i < matches.Count(); ++i) {
+    nsNavHistoryResultNode* node = matches[i];
+    nsNavHistoryContainerResultNode* parent = node->mParent;
+    // URI nodes should always have parents
+    NS_ENSURE_TRUE(parent, NS_ERROR_UNEXPECTED);
+
+    int32_t childIndex = parent->FindChild(node);
+    NS_ASSERTION(childIndex >= 0, "Child not found in parent");
+    parent->RemoveChildAt(childIndex);
+    if (parent->mChildren.Count() == 0 && parent->IsQuery() &&
+        parent->mIndentLevel > -1) {
+      // When query subcontainers (like hosts) get empty we should remove them
+      // as well.  If the parent is not the root node, append it to our list
+      // and it will get evaluated later in the loop.
+      matches.AppendObject(parent);
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnClearHistory() {
+  nsresult rv = Refresh();
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+static nsresult setFaviconCallback(nsNavHistoryResultNode* aNode,
+                                   const void* aClosure,
+                                   const nsNavHistoryResult* aResult) {
+  if (aResult && (!aNode->mParent || aNode->mParent->AreChildrenVisible())) {
+    NOTIFY_RESULT_OBSERVERS(aResult, NodeIconChanged(aNode));
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnPageRemovedVisits(
+    nsIURI* aURI, bool aPartialRemoval, const nsACString& aGUID,
+    uint16_t aReason, uint32_t aTransitionType) {
+  MOZ_ASSERT(
+      mOptions->QueryType() == nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY,
+      "Bookmarks queries should not get a OnDeleteVisits notification");
+
+  if (!aPartialRemoval) {
+    // All visits for this uri have been removed, but the uri won't be removed
+    // from the databse, most likely because it's a bookmark.  For a history
+    // query this is equivalent to a OnPageRemovedFromStore notification.
+    nsresult rv = OnPageRemovedFromStore(aURI, aGUID, aReason);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else if (aReason == PlacesVisitRemoved_Binding::REASON_DELETED &&
+             isTimeFilteredQuery(mQuery)) {
+    // If the query has time filters we must Refresh because we don't know
+    // which visits have been removed, it could be all the visits in the
+    // filtered timeframe.
+    // We skip this for expired visits, to avoid surprising the user with pages
+    // disappearing from the UI.
+    return Refresh();
+  }
+  if (aTransitionType > 0) {
+    // All visits for aTransitionType have been removed, if the query is
+    // filtering on such transition type, this is equivalent to an
+    // OnPageRemovedFromStore notification.
+    if (mTransitions.Length() > 0 && mTransitions.Contains(aTransitionType)) {
+      nsresult rv = OnPageRemovedFromStore(aURI, aGUID, aReason);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  return NS_OK;
+}
+
+/**
+ * These are the bookmark observer functions for query nodes.  They listen
+ * for bookmark events and refresh the results if we have any dependence on
+ * the bookmark system.
+ */
+nsresult nsNavHistoryQueryResultNode::OnItemAdded(
+    int64_t aItemId, int64_t aParentId, int32_t aIndex, uint16_t aItemType,
+    nsIURI* aURI, PRTime aDateAdded, const nsACString& aGUID,
+    const nsACString& aParentGUID, uint16_t aSource) {
+  if (aItemType == nsINavBookmarksService::TYPE_BOOKMARK &&
+      mLiveUpdate != QUERYUPDATE_SIMPLE && mLiveUpdate != QUERYUPDATE_TIME &&
+      mLiveUpdate != QUERYUPDATE_MOBILEPREF) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemRemoved(
+    int64_t aItemId, int64_t aParentFolder, int32_t aIndex, uint16_t aItemType,
+    nsIURI* aURI, const nsACString& aGUID, const nsACString& aParentGUID,
+    uint16_t aSource) {
+  if ((aItemType == nsINavBookmarksService::TYPE_BOOKMARK ||
+       (aItemType == nsINavBookmarksService::TYPE_FOLDER &&
+        mOptions->ResultType() ==
+            nsINavHistoryQueryOptions::RESULTS_AS_TAGS_ROOT &&
+        aParentGUID.EqualsLiteral(TAGS_ROOT_GUID))) &&
+      mLiveUpdate != QUERYUPDATE_SIMPLE && mLiveUpdate != QUERYUPDATE_TIME &&
+      mLiveUpdate != QUERYUPDATE_MOBILEPREF) {
+    nsresult rv = Refresh();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemMoved(
+    int64_t aFolder, int32_t aOldIndex, int32_t aNewIndex, uint16_t aItemType,
+    const nsACString& aGUID, const nsACString& aOldParentGUID,
+    const nsACString& aNewParentGUID, uint16_t aSource,
+    const nsACString& aURI) {
+  // 1. The query cannot be affected by the item's position
+  // 2. For the time being, we cannot optimize this not to update
+  //    queries which are not restricted to some folders, due to way
+  //    sub-queries are updated (see Refresh)
+  if (mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS &&
+      aItemType != nsINavBookmarksService::TYPE_SEPARATOR &&
+      !aNewParentGUID.Equals(aOldParentGUID)) {
+    return Refresh();
+  }
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemTagsChanged(
+    int64_t aItemId, const nsAString& aURL, const nsAString& aTags) {
+  nsresult rv = nsNavHistoryResultNode::OnItemTagsChanged(aItemId, aURL, aTags);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+
+  // Check whether aURL is actually URI.
+  nsCOMPtr<nsIURI> uri;
+  rv = NS_NewURI(getter_AddRefs(uri), aURL);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString spec;
+  rv = uri->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool onlyOneEntry =
+      mOptions->ResultType() == nsINavHistoryQueryOptions::RESULTS_AS_URI;
+
+  nsCOMArray<nsNavHistoryResultNode> matches;
+  RecursiveFindURIs(onlyOneEntry, this, spec, &matches);
+
+  if (matches.Count() == 0 && mHasSearchTerms) {
+    return isQuerySearchTermsMatching(mQuery, this) ? Refresh() : NS_OK;
+  }
+
+  for (int32_t i = 0; i < matches.Count(); ++i) {
+    nsNavHistoryResultNode* node = matches[i];
+    node->SetTags(aTags);
+    // It's possible now this node does not respect anymore the conditions.
+    // In such a case it should be removed.
+    if (mHasSearchTerms && !isQuerySearchTermsMatching(mQuery, node)) {
+      nsNavHistoryContainerResultNode* parent = node->mParent;
+      // URI nodes should always have parents
+      NS_ENSURE_TRUE(parent, NS_ERROR_UNEXPECTED);
+      int32_t childIndex = parent->FindChild(node);
+      NS_ASSERTION(childIndex >= 0, "Child not found in parent");
+      parent->RemoveChildAt(childIndex);
+    } else {
+      NOTIFY_RESULT_OBSERVERS(result, NodeTagsChanged(node));
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemTimeChanged(int64_t aItemId,
+                                                        const nsACString& aGUID,
+                                                        PRTime aDateAdded,
+                                                        PRTime aLastModified) {
+  // Update ourselves first.
+  nsresult rv = nsNavHistoryResultNode::OnItemTimeChanged(
+      aItemId, aGUID, aDateAdded, aLastModified);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS) {
+    return Refresh();
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemTitleChanged(
+    int64_t aItemId, const nsACString& aGUID, const nsACString& aTitle,
+    PRTime aLastModified) {
+  // Update ourselves first.
+  nsresult rv = nsNavHistoryResultNode::OnItemTitleChanged(
+      aItemId, aGUID, aTitle, aLastModified);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS) {
+    return Refresh();
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryQueryResultNode::OnItemUrlChanged(int64_t aItemId,
+                                                       const nsACString& aGUID,
+                                                       const nsACString& aURL,
+                                                       PRTime aLastModified) {
+  if (aItemId == mItemId) {
+    nsresult rv = nsNavHistoryResultNode::OnItemUrlChanged(aItemId, aGUID, aURL,
+                                                           aLastModified);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    nsNavHistory* history = nsNavHistory::GetHistoryService();
+    NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+    nsCOMPtr<nsINavHistoryQuery> query;
+    nsCOMPtr<nsINavHistoryQueryOptions> options;
+    rv = history->QueryStringToQuery(mURI, getter_AddRefs(query),
+                                     getter_AddRefs(options));
+    NS_ENSURE_SUCCESS(rv, rv);
+    mQuery = do_QueryObject(query);
+    NS_ENSURE_STATE(mQuery);
+    mOptions = do_QueryObject(options);
+    NS_ENSURE_STATE(mOptions);
+    rv = mOptions->Clone(getter_AddRefs(mOriginalOptions));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return Refresh();
+  }
+
+  if (mLiveUpdate == QUERYUPDATE_COMPLEX_WITH_BOOKMARKS) {
+    return Refresh();
+  }
+
+  int32_t index;
+  nsNavHistoryResultNode* node = FindChildById(aItemId, &index);
+  if (node) {
+    return node->OnItemUrlChanged(aItemId, aGUID, aURL, aLastModified);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * HOW DYNAMIC FOLDER UPDATING WORKS
+ *
+ * When you create a result, it will automatically keep itself in sync with
+ * stuff that happens in the system.  For folder nodes, this means changes to
+ * bookmarks.
+ *
+ * A folder will fill its children "when necessary." This means it is being
+ * opened or whether we need to see if it is empty for twisty drawing.  It will
+ * then register its ID with the main result object that owns it.  This result
+ * object will listen for all bookmark notifications and pass those
+ * notifications to folder nodes that have registered for that specific folder
+ * ID.
+ *
+ * When a bookmark folder is closed, it will not clear its children.  Instead,
+ * it will keep them and also stay registered as a listener.  This means that
+ * you can more quickly re-open the same folder without doing any work.  This
+ * happens a lot for menus, and bookmarks don't change very often.
+ *
+ * When a message comes in and the folder is open, we will do the correct
+ * operations to keep ourselves in sync with the bookmark service.  If the
+ * folder is closed, we just clear our list to mark it as invalid and
+ * unregister as a listener.  This means we do not have to keep maintaining
+ * an up-to-date list for the entire bookmark menu structure in every place
+ * it is used.
+ */
+NS_IMPL_ISUPPORTS_INHERITED(nsNavHistoryFolderResultNode,
+                            nsNavHistoryContainerResultNode,
+                            nsINavHistoryQueryResultNode,
+                            mozIStorageStatementCallback)
+
+nsNavHistoryFolderResultNode::nsNavHistoryFolderResultNode(
+    int64_t aItemId, const nsACString& aBookmarkGuid,
+    int64_t aTargetFolderItemId, const nsACString& aTargetFolderGuid,
+    const nsACString& aTitle, nsNavHistoryQueryOptions* aOptions)
+    : nsNavHistoryContainerResultNode(
+          ""_ns, aTitle, 0, nsNavHistoryResultNode::RESULT_TYPE_FOLDER,
+          aOptions),
+      mContentsValid(false),
+      mTargetFolderItemId(aTargetFolderItemId),
+      mTargetFolderGuid(aTargetFolderGuid),
+      mIsRegisteredFolderObserver(false),
+      mAsyncBookmarkIndex(-1) {
+  mItemId = aItemId;
+  mBookmarkGuid = aBookmarkGuid;
+}
+
+nsNavHistoryFolderResultNode::~nsNavHistoryFolderResultNode() {
+  if (mIsRegisteredFolderObserver && mResult) {
+    mResult->RemoveBookmarkFolderObserver(this, mTargetFolderGuid);
+  }
+}
+
+/**
+ * Here we do not want to call ContainerResultNode::OnRemoving since our own
+ * ClearChildren will do the same thing and more (unregister the observers).
+ * The base ResultNode::OnRemoving will clear some regular node stats, so it is
+ * OK.
+ */
+void nsNavHistoryFolderResultNode::OnRemoving() {
+  nsNavHistoryResultNode::OnRemoving();
+  ClearChildren(true);
+  mResult = nullptr;
+}
+
+nsresult nsNavHistoryFolderResultNode::OpenContainer() {
+  NS_ASSERTION(!mExpanded, "Container must be expanded to close it");
+  nsresult rv;
+
+  if (!mContentsValid) {
+    rv = FillChildren();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  mExpanded = true;
+
+  rv = NotifyOnStateChange(STATE_CLOSED);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+/**
+ * The async version of OpenContainer.
+ */
+nsresult nsNavHistoryFolderResultNode::OpenContainerAsync() {
+  NS_ASSERTION(!mExpanded, "Container already expanded when opening it");
+
+  // If the children are valid, open the container synchronously.  This will be
+  // the case when the container has already been opened and any other time
+  // FillChildren or FillChildrenAsync has previously been called.
+  if (mContentsValid) return OpenContainer();
+
+  nsresult rv = FillChildrenAsync();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = NotifyOnStateChange(STATE_CLOSED);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+/**
+ * @see nsNavHistoryQueryResultNode::HasChildren.  The semantics here are a
+ * little different.  Querying the contents of a bookmark folder is relatively
+ * fast and it is common to have empty folders.  Therefore, we always want to
+ * return the correct result so that twisties are drawn properly.
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetHasChildren(bool* aHasChildren) {
+  if (!mContentsValid) {
+    nsresult rv = FillChildren();
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  *aHasChildren = (mChildren.Count() > 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetFolderItemId(int64_t* aItemId) {
+  *aItemId = mTargetFolderItemId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetTargetFolderGuid(nsACString& aGuid) {
+  aGuid = mTargetFolderGuid;
+  return NS_OK;
+}
+
+/**
+ * Lazily computes the URI for this specific folder query with the current
+ * options.
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetUri(nsACString& aURI) {
+  if (!mURI.IsEmpty()) {
+    aURI = mURI;
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsINavHistoryQuery> query;
+  nsresult rv = GetQuery(getter_AddRefs(query));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsNavHistory* history = nsNavHistory::GetHistoryService();
+  NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+  rv = history->QueryToQueryString(query, mOriginalOptions, mURI);
+  NS_ENSURE_SUCCESS(rv, rv);
+  aURI = mURI;
+  return NS_OK;
+}
+
+/**
+ * @return the queries that give you this bookmarks folder
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetQuery(nsINavHistoryQuery** _query) {
+  // get the query object
+  RefPtr<nsNavHistoryQuery> query = new nsNavHistoryQuery();
+
+  nsTArray<nsCString> parents;
+  // query just has the folder ID set and nothing else
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier, or change the return type to void.
+  parents.AppendElement(mTargetFolderGuid);
+  nsresult rv = query->SetParents(parents);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  query.forget(_query);
+  return NS_OK;
+}
+
+/**
+ * Options for the query that gives you this bookmarks folder.  This is just
+ * the options for the folder with the current folder ID set.
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::GetQueryOptions(
+    nsINavHistoryQueryOptions** _options) {
+  MOZ_ASSERT(mOptions, "Options should be valid");
+  RefPtr<nsNavHistoryQueryOptions> options = mOptions;
+  options.forget(_options);
+  return NS_OK;
+}
+
+nsresult nsNavHistoryFolderResultNode::FillChildren() {
+  NS_ASSERTION(!mContentsValid,
+               "Don't call FillChildren when contents are valid");
+  NS_ASSERTION(mChildren.Count() == 0,
+               "We are trying to fill children when there already are some");
+
+  nsNavBookmarks* bookmarks = nsNavBookmarks::GetBookmarksService();
+  NS_ENSURE_TRUE(bookmarks, NS_ERROR_OUT_OF_MEMORY);
+
+  // Actually get the folder children from the bookmark service.
+  nsresult rv =
+      bookmarks->QueryFolderChildren(mTargetFolderItemId, mOptions, &mChildren);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // PERFORMANCE: it may be better to also fill any child folders at this point
+  // so that we can draw tree twisties without doing a separate query later.
+  // If we don't end up drawing twisties a lot, it doesn't matter. If we do
+  // this, we should wrap everything in a transaction here on the bookmark
+  // service's connection.
+
+  return OnChildrenFilled();
+}
+
+/**
+ * Performs some tasks after all the children of the container have been added.
+ * The container's contents are not valid until this method has been called.
+ */
+nsresult nsNavHistoryFolderResultNode::OnChildrenFilled() {
+  // It is important to call FillStats to fill in the parents on all
+  // nodes and the result node pointers on the containers.
+  FillStats();
+
+  if (mResult && mResult->mNeedsToApplySortingMode) {
+    // We should repopulate container and then apply sortingMode.  To avoid
+    // sorting 2 times we simply do that here.
+    mResult->SetSortingMode(mResult->mSortingMode);
+  } else {
+    // Once we've computed all tree stats, we can sort, because containers will
+    // then have proper visit counts and dates.
+    SortComparator comparator = GetSortingComparator(GetSortType());
+    if (comparator) {
+      RecursiveSort(comparator);
+    }
+  }
+
+  // If we are limiting our results remove items from the end of the
+  // mChildren array after sorting.  This is done for root node only.
+  // Note, if count < max results, we won't do anything.
+  if (!mParent && mOptions->MaxResults()) {
+    while (mChildren.Length() > mOptions->MaxResults()) {
+      mChildren.RemoveObjectAt(mChildren.Count() - 1);
+    }
+  }
+
+  // Register with the result for updates.
+  EnsureRegisteredAsFolderObserver();
+
+  mContentsValid = true;
+  return NS_OK;
+}
+
+/**
+ * Registers the node with its result as a folder observer if it is not already
+ * registered.
+ */
+void nsNavHistoryFolderResultNode::EnsureRegisteredAsFolderObserver() {
+  if (!mIsRegisteredFolderObserver && mResult) {
+    mResult->AddBookmarkFolderObserver(this, mTargetFolderGuid);
+    mIsRegisteredFolderObserver = true;
+  }
+}
+
+/**
+ * The async version of FillChildren.  This begins asynchronous execution by
+ * calling nsNavBookmarks::QueryFolderChildrenAsync.  During execution, this
+ * node's async Storage callbacks, HandleResult and HandleCompletion, will be
+ * called.
+ */
+nsresult nsNavHistoryFolderResultNode::FillChildrenAsync() {
+  NS_ASSERTION(!mContentsValid, "FillChildrenAsync when contents are valid");
+  NS_ASSERTION(mChildren.Count() == 0, "FillChildrenAsync when children exist");
+
+  // ProcessFolderNodeChild, called in HandleResult, increments this for every
+  // result row it processes.  Initialize it here as we begin async execution.
+  mAsyncBookmarkIndex = -1;
+
+  nsNavBookmarks* bmSvc = nsNavBookmarks::GetBookmarksService();
+  NS_ENSURE_TRUE(bmSvc, NS_ERROR_OUT_OF_MEMORY);
+  nsresult rv =
+      bmSvc->QueryFolderChildrenAsync(this, getter_AddRefs(mAsyncPendingStmt));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Register with the result for updates.  All updates during async execution
+  // will cause it to be restarted.
+  EnsureRegisteredAsFolderObserver();
+
+  return NS_OK;
+}
+
+/**
+ * A mozIStorageStatementCallback method.  Called during the async execution
+ * begun by FillChildrenAsync.
+ *
+ * @param aResultSet
+ *        The result set containing the data from the database.
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::HandleResult(mozIStorageResultSet* aResultSet) {
+  NS_ENSURE_ARG_POINTER(aResultSet);
+
+  nsNavBookmarks* bmSvc = nsNavBookmarks::GetBookmarksService();
+  if (!bmSvc) {
+    CancelAsyncOpen(false);
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // Consume all the currently available rows of the result set.
+  nsCOMPtr<mozIStorageRow> row;
+  while (NS_SUCCEEDED(aResultSet->GetNextRow(getter_AddRefs(row))) && row) {
+    nsresult rv = bmSvc->ProcessFolderNodeRow(row, mOptions, &mChildren,
+                                              mAsyncBookmarkIndex);
+    if (NS_FAILED(rv)) {
+      CancelAsyncOpen(false);
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
+/**
+ * A mozIStorageStatementCallback method.  Called during the async execution
+ * begun by FillChildrenAsync.
+ *
+ * @param aReason
+ *        Indicates the final state of execution.
+ */
+NS_IMETHODIMP
+nsNavHistoryFolderResultNode::HandleCompletion(uint16_t aReason) {
+  if (aReason == mozIStorageStatementCallback::REASON_FINISHED &&
+      mAsyncCanceledState == NOT_CANCELED) {
+    // Async execution successfully completed.  The container is ready to open.
+
+    nsresult rv = OnChildrenFilled();
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    mExpanded = true;
+    mAsyncPendingStmt = nullptr;
+
+    // Notify observers only after mExpanded and mAsyncPendingStmt are set.
+    rv = NotifyOnStateChange(STATE_LOADING);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  else if (mAsyncCanceledState == CANCELED_RESTART_NEEDED) {
+    // Async execution was canceled and needs to be restarted.
+    mAsyncCanceledState = NOT_CANCELED;
+    ClearChildren(false);
+    FillChildrenAsync();
+  }
+
+  else {
+    // Async execution failed or was canceled without restart.  Remove all
+    // children and close the container, notifying observers.
+    mAsyncCanceledState = NOT_CANCELED;
+    ClearChildren(true);
+    CloseContainer();
+  }
+
+  return NS_OK;
+}
+
+void nsNavHistoryFolderResultNode::ClearChildren(bool unregister) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) mChildren[i]->OnRemoving();
+  mChildren.Clear();
+
+  bool needsUnregister = unregister && (mContentsValid || mAsyncPendingStmt);
+  if (needsUnregister && mResult && mIsRegisteredFolderObserver) {
+    mResult->RemoveBookmarkFolderObserver(this, mTargetFolderGuid);
+    mIsRegisteredFolderObserver = false;
+  }
+  mContentsValid = false;
+}
+
+/**
+ * This is called to update the result when something has changed that we
+ * can not incrementally update.
+ */
+nsresult nsNavHistoryFolderResultNode::Refresh() {
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  if (result->IsBatching()) {
+    result->requestRefresh(this);
+    return NS_OK;
+  }
+
+  ClearChildren(true);
+
+  if (!mExpanded) {
+    // When we are not expanded, we don't update, just invalidate and unhook.
+    return NS_OK;
+  }
+
+  // Ignore errors from FillChildren, since we will still want to refresh
+  // the tree (there just might not be anything in it on error).  ClearChildren
+  // has unregistered us as an observer since FillChildren will try to
+  // re-register us.
+  (void)FillChildren();
+
+  NOTIFY_RESULT_OBSERVERS(result, InvalidateContainer(TO_CONTAINER(this)));
+  return NS_OK;
+}
+
+/**
+ * Implements the logic described above the constructor.  This sees if we
+ * should do an incremental update and returns true if so.  If not, it
+ * invalidates our children, unregisters us an observer, and returns false.
+ */
+bool nsNavHistoryFolderResultNode::StartIncrementalUpdate() {
+  // if any items are excluded, we can not do incremental updates since the
+  // indices from the bookmark service will not be valid
+
+  if (!mOptions->ExcludeItems() && !mOptions->ExcludeQueries()) {
+    // easy case: we are visible, always do incremental update
+    if (mExpanded || AreChildrenVisible()) return true;
+
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_TRUE(result, false);
+
+    // When any observers are attached also do incremental updates if our
+    // parent is visible, so that twisties are drawn correctly.
+    if (mParent) return result->mObservers.Length() > 0;
+  }
+
+  // otherwise, we don't do incremental updates, invalidate and unregister
+  (void)Refresh();
+  return false;
+}
+
+/**
+ * This function adds aDelta to all bookmark indices between the two endpoints,
+ * inclusive.  It is used when items are added or removed from the bookmark
+ * folder.
+ */
+void nsNavHistoryFolderResultNode::ReindexRange(int32_t aStartIndex,
+                                                int32_t aEndIndex,
+                                                int32_t aDelta) {
+  for (int32_t i = 0; i < mChildren.Count(); ++i) {
+    nsNavHistoryResultNode* node = mChildren[i];
+    if (node->mBookmarkIndex >= aStartIndex &&
+        node->mBookmarkIndex <= aEndIndex) {
+      node->mBookmarkIndex += aDelta;
+    }
+  }
+}
+
+// Used by nsNavHistoryFolderResultNode's methods below. If the container is
+// notified of a bookmark event while asynchronous execution is pending, this
+// restarts it and returns.
+#define RESTART_AND_RETURN_IF_ASYNC_PENDING() \
+  if (mAsyncPendingStmt) {                    \
+    CancelAsyncOpen(true);                    \
+    return NS_OK;                             \
+  }
+
+nsresult nsNavHistoryFolderResultNode::OnBeginUpdateBatch() { return NS_OK; }
+
+nsresult nsNavHistoryFolderResultNode::OnEndUpdateBatch() { return NS_OK; }
+
+nsresult nsNavHistoryFolderResultNode::OnItemAdded(
+    int64_t aItemId, int64_t aParentFolder, int32_t aIndex, uint16_t aItemType,
+    nsIURI* aURI, PRTime aDateAdded, const nsACString& aGUID,
+    const nsACString& aParentGUID, uint16_t aSource, const nsACString& aTitle,
+    const nsAString& aTags, int64_t aFrecency, bool aHidden,
+    uint32_t aVisitCount, PRTime aLastVisitDate, int64_t aTargetFolderItemId,
+    const nsACString& aTargetFolderGuid, const nsACString& aTargetFolderTitle) {
+  MOZ_ASSERT(aParentFolder == mTargetFolderItemId, "Got wrong bookmark update");
+
+  RESTART_AND_RETURN_IF_ASYNC_PENDING();
+
+  {
+    int32_t index;
+    nsNavHistoryResultNode* node = FindChildById(aItemId, &index);
+    // Bug 1097528.
+    // It's possible our result registered due to a previous notification, for
+    // example the Library left pane could have refreshed and replaced the
+    // right pane as a consequence. In such a case our contents are already
+    // up-to-date.  That's OK.
+    if (node) return NS_OK;
+  }
+
+  bool excludeItems = mOptions->ExcludeItems();
+
+  // here, try to do something reasonable if the bookmark service gives us
+  // a bogus index.
+  if (aIndex < 0) {
+    MOZ_ASSERT_UNREACHABLE("Invalid index for item adding: <0");
+    aIndex = 0;
+  } else if (aIndex > mChildren.Count()) {
+    if (!excludeItems) {
+      // Something wrong happened while updating indexes.
+      MOZ_ASSERT_UNREACHABLE(
+          "Invalid index for item adding: greater than "
+          "count");
+    }
+    aIndex = mChildren.Count();
+  }
+
+  nsresult rv;
+
+  // Check for query URIs, which are bookmarks, but treated as containers
+  // in results and views.
+  bool isQuery = false;
+  nsAutoCString itemURISpec;
+  if (aItemType == nsINavBookmarksService::TYPE_BOOKMARK) {
+    NS_ASSERTION(aURI, "Got a null URI when we are a bookmark?!");
+    rv = aURI->GetSpec(itemURISpec);
+    NS_ENSURE_SUCCESS(rv, rv);
+    isQuery = IsQueryURI(itemURISpec);
+  }
+
+  if (aItemType != nsINavBookmarksService::TYPE_FOLDER && !isQuery &&
+      excludeItems) {
+    // don't update items when we aren't displaying them, but we still need
+    // to adjust bookmark indices to account for the insertion
+    ReindexRange(aIndex, INT32_MAX, 1);
+    return NS_OK;
+  }
+
+  if (!StartIncrementalUpdate()) {
+    return NS_OK;  // folder was completely refreshed for us
+  }
+
+  // adjust indices to account for insertion
+  ReindexRange(aIndex, INT32_MAX, 1);
+
+  RefPtr<nsNavHistoryResultNode> node;
+  if (aItemType == nsINavBookmarksService::TYPE_BOOKMARK) {
+    if (isQuery) {
+      nsNavHistory* history = nsNavHistory::GetHistoryService();
+      NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+      rv = history->QueryUriToResult(itemURISpec, aItemId, aGUID, aTitle,
+                                     aTargetFolderItemId, aTargetFolderGuid,
+                                     aTargetFolderTitle, aVisitCount,
+                                     aLastVisitDate, getter_AddRefs(node));
+      NS_ENSURE_SUCCESS(rv, rv);
+    } else {
+      node = new nsNavHistoryResultNode(itemURISpec, aTitle, aVisitCount,
+                                        aLastVisitDate);
+      node->mItemId = aItemId;
+      node->mBookmarkGuid = aGUID;
+    }
+
+    node->SetTags(aTags);
+    node->mDateAdded = aDateAdded;
+    node->mLastModified = aDateAdded;
+    node->mFrecency = aFrecency;
+    node->mHidden = aHidden;
+  } else if (aItemType == nsINavBookmarksService::TYPE_FOLDER) {
+    node = new nsNavHistoryFolderResultNode(
+        aItemId, aGUID, aItemId, aGUID, aTitle, new nsNavHistoryQueryOptions());
+    node->mDateAdded = aDateAdded;
+    node->mLastModified = aDateAdded;
+  } else if (aItemType == nsINavBookmarksService::TYPE_SEPARATOR) {
+    node = new nsNavHistorySeparatorResultNode();
+    node->mItemId = aItemId;
+    node->mBookmarkGuid = aGUID;
+    node->mDateAdded = aDateAdded;
+    node->mLastModified = aDateAdded;
+  }
+
+  node->mBookmarkIndex = aIndex;
+
+  if (aItemType == nsINavBookmarksService::TYPE_SEPARATOR ||
+      GetSortType() == nsINavHistoryQueryOptions::SORT_BY_NONE) {
+    // insert at natural bookmarks position
+    return InsertChildAt(node, aIndex);
+  }
+
+  // insert at sorted position
+  return InsertSortedChild(node);
+}
+
+nsresult nsNavHistoryQueryResultNode::OnMobilePrefChanged(bool newValue) {
+  RESTART_AND_RETURN_IF_ASYNC_PENDING();
+
+  if (newValue) {
+    // If the folder is being added, simply refresh the query as that is
+    // simpler than re-inserting just the mobile folder.
+    return Refresh();
+  }
+
+  // We're removing the mobile folder, so find it.
+  int32_t existingIndex;
+  FindChildByGuid(nsLiteralCString(MOBILE_BOOKMARKS_VIRTUAL_GUID),
+                  &existingIndex);
+
+  if (existingIndex == -1) {
+    return NS_OK;
+  }
+
+  return RemoveChildAt(existingIndex);
+}
+
+nsresult nsNavHistoryFolderResultNode::OnItemRemoved(
+    int64_t aItemId, int64_t aParentFolder, int32_t aIndex, uint16_t aItemType,
+    nsIURI* aURI, const nsACString& aGUID, const nsACString& aParentGUID,
+    uint16_t aSource) {
+  // Folder shortcuts should not be notified removal of the target folder.
+  MOZ_ASSERT_IF(mItemId != mTargetFolderItemId, aItemId != mTargetFolderItemId);
+  // Concrete folders should not be notified their own removal.
+  // Note aItemId may equal mItemId for recursive folder shortcuts.
+  MOZ_ASSERT_IF(mItemId == mTargetFolderItemId, aItemId != mItemId);
+
+  // In any case though, here we only care about the children removal.
+  if (mTargetFolderItemId == aItemId || mItemId == aItemId) return NS_OK;
+
+  MOZ_ASSERT(aParentFolder == mTargetFolderItemId, "Got wrong bookmark update");
+
+  RESTART_AND_RETURN_IF_ASYNC_PENDING();
+
+  // don't trust the index from the bookmark service, find it ourselves.  The
+  // sorting could be different, or the bookmark services indices and ours might
+  // be out of sync somehow.
+  int32_t index;
+  nsNavHistoryResultNode* node = FindChildById(aItemId, &index);
+  // Bug 1097528.
+  // It's possible our result registered due to a previous notification, for
+  // example the Library left pane could have refreshed and replaced the
+  // right pane as a consequence. In such a case our contents are already
+  // up-to-date.  That's OK.
+  if (!node) {
+    return NS_OK;
+  }
+
+  bool excludeItems = mOptions->ExcludeItems();
+
+  if ((node->IsURI() || node->IsSeparator()) && excludeItems) {
+    // don't update items when we aren't displaying them, but we do need to
+    // adjust everybody's bookmark indices to account for the removal
+    ReindexRange(aIndex, INT32_MAX, -1);
+    return NS_OK;
+  }
+
+  if (!StartIncrementalUpdate()) return NS_OK;  // we are completely refreshed
+
+  // shift all following indices down
+  ReindexRange(aIndex + 1, INT32_MAX, -1);
+
+  return RemoveChildAt(index);
+}
+
+nsresult nsNavHistoryResultNode::OnItemKeywordChanged(
+    int64_t aItemId, const nsACString& aKeyword) {
+  if (aItemId != mItemId) {
+    return NS_OK;
+  }
+
+  bool shouldNotify = !mParent || mParent->AreChildrenVisible();
+  if (shouldNotify) {
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_STATE(result);
+    NOTIFY_RESULT_OBSERVERS(result, NodeKeywordChanged(this, aKeyword));
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResultNode::OnItemTagsChanged(int64_t aItemId,
+                                                   const nsAString& aURL,
+                                                   const nsAString& aTags) {
+  if (aItemId != mItemId) {
+    return NS_OK;
+  }
+
+  SetTags(aTags);
+
+  bool shouldNotify = !mParent || mParent->AreChildrenVisible();
+  if (shouldNotify) {
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_STATE(result);
+    NOTIFY_RESULT_OBSERVERS(result, NodeTagsChanged(this));
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResultNode::OnItemTimeChanged(int64_t aItemId,
+                                                   const nsACString& aGUID,
+                                                   PRTime aDateAdded,
+                                                   PRTime aLastModified) {
+  if (aItemId != mItemId) {
+    return NS_OK;
+  }
+
+  bool isDateAddedChanged = mDateAdded != aDateAdded;
+  bool isLastModifiedChanged = mLastModified != aLastModified;
+
+  if (!isDateAddedChanged && !isLastModifiedChanged) {
+    return NS_OK;
+  }
+
+  mDateAdded = aDateAdded;
+  mLastModified = aLastModified;
+
+  bool shouldNotify = !mParent || mParent->AreChildrenVisible();
+  if (shouldNotify) {
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_STATE(result);
+
+    if (isDateAddedChanged) {
+      NOTIFY_RESULT_OBSERVERS(result, NodeDateAddedChanged(this, aDateAdded));
+    }
+    if (isLastModifiedChanged) {
+      NOTIFY_RESULT_OBSERVERS(result,
+                              NodeLastModifiedChanged(this, aLastModified));
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResultNode::OnItemTitleChanged(int64_t aItemId,
+                                                    const nsACString& aGUID,
+                                                    const nsACString& aTitle,
+                                                    PRTime aLastModified) {
+  if (aItemId != mItemId) {
+    return NS_OK;
+  }
+
+  mTitle = aTitle;
+  mLastModified = aLastModified;
+
+  bool shouldNotify = !mParent || mParent->AreChildrenVisible();
+  if (shouldNotify) {
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_STATE(result);
+    NOTIFY_RESULT_OBSERVERS(result, NodeTitleChanged(this, mTitle));
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResultNode::OnItemUrlChanged(int64_t aItemId,
+                                                  const nsACString& aGUID,
+                                                  const nsACString& aURL,
+                                                  PRTime aLastModified) {
+  if (aItemId != mItemId) {
+    return NS_OK;
+  }
+
+  // clear the tags string as well
+  mTags.SetIsVoid(true);
+  nsCString oldURI(mURI);
+  mURI = aURL;
+  mLastModified = aLastModified;
+
+  bool shouldNotify = !mParent || mParent->AreChildrenVisible();
+  if (shouldNotify) {
+    nsNavHistoryResult* result = GetResult();
+    NS_ENSURE_STATE(result);
+    NOTIFY_RESULT_OBSERVERS(result, NodeURIChanged(this, oldURI));
+  }
+
+  if (!mParent) return NS_OK;
+
+  // The sorting methods fall back to each other so we need to re-sort the
+  // result even if it's not set to sort by the given property.
+  int32_t ourIndex = mParent->FindChild(this);
+  NS_ASSERTION(ourIndex >= 0, "Could not find self in parent");
+  if (ourIndex >= 0) {
+    mParent->EnsureItemPosition(ourIndex);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResultNode::OnVisitsRemoved() {
+  PRTime oldTime = mTime;
+  mTime = 0;
+
+  nsNavHistoryResult* result = GetResult();
+  NS_ENSURE_STATE(result);
+  NOTIFY_RESULT_OBSERVERS(
+      result, NodeHistoryDetailsChanged(this, oldTime, mAccessCount));
+
+  return NS_OK;
+}
+
+/**
+ * Updates visit count and last visit time and refreshes.
+ */
+nsresult nsNavHistoryFolderResultNode::OnItemVisited(nsIURI* aURI,
+                                                     int64_t aVisitId,
+                                                     PRTime aTime,
+                                                     int64_t aFrecency) {
+  if (mOptions->ExcludeItems()) {
+    return NS_OK;  // don't update items when we aren't displaying them
+  }
+
+  RESTART_AND_RETURN_IF_ASYNC_PENDING();
+
+  if (!StartIncrementalUpdate()) return NS_OK;
+
+  nsAutoCString spec;
+  nsresult rv = aURI->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMArray<nsNavHistoryResultNode> nodes;
+  FindChildrenByURI(spec, &nodes);
+  if (!nodes.Count()) {
+    return NS_OK;
+  }
+
+  // Update us.
+  uint32_t oldAccessCount = mAccessCount;
+  ++mAccessCount;
+  if (aTime > mTime) {
+    mTime = aTime;
+  }
+  rv = ReverseUpdateStats(static_cast<int32_t>(mAccessCount) -
+                          static_cast<int32_t>(oldAccessCount));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Update nodes.
+  for (int32_t i = 0; i < nodes.Count(); ++i) {
+    nsNavHistoryResultNode* node = nodes[i];
+    uint32_t nodeOldAccessCount = node->mAccessCount;
+    PRTime nodeOldTime = node->mTime;
+    if (node->mTime < aTime) {
+      node->mTime = aTime;
+    }
+    ++node->mAccessCount;
+    node->mFrecency = aFrecency;
+
+    nsNavHistoryResult* result = GetResult();
+    if (AreChildrenVisible() && !result->CanSkipHistoryDetailsNotifications()) {
+      // Sorting has not changed, just redraw the row if it's visible.
+      NOTIFY_RESULT_OBSERVERS(
+          result,
+          NodeHistoryDetailsChanged(node, nodeOldTime, nodeOldAccessCount));
+    }
+
+    // Update sorting if necessary.
+    uint32_t sortType = GetSortType();
+    if (sortType == nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING ||
+        sortType == nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING ||
+        sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING ||
+        sortType == nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING ||
+        sortType == nsINavHistoryQueryOptions::SORT_BY_FRECENCY_ASCENDING ||
+        sortType == nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING) {
+      int32_t childIndex = FindChild(node);
+      NS_ASSERTION(childIndex >= 0,
+                   "Could not find child we just got a reference to");
+      if (childIndex >= 0) {
+        EnsureItemPosition(childIndex);
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryFolderResultNode::OnItemMoved(
+    int64_t aItemId, int32_t aOldIndex, int32_t aNewIndex, uint16_t aItemType,
+    const nsACString& aGUID, const nsACString& aOldParentGUID,
+    const nsACString& aNewParentGUID, uint16_t aSource, const nsACString& aURI,
+    const nsACString& aTitle, const nsAString& aTags, int64_t aFrecency,
+    bool aHidden, uint32_t aVisitCount, PRTime aLastVisitDate,
+    PRTime aDateAdded) {
+  MOZ_ASSERT(aOldParentGUID.Equals(mTargetFolderGuid) ||
+                 aNewParentGUID.Equals(mTargetFolderGuid),
+             "Got a bookmark message that doesn't belong to us");
+
+  RESTART_AND_RETURN_IF_ASYNC_PENDING();
+
+  bool excludeItems = mOptions->ExcludeItems();
+  if (excludeItems && (aItemType == nsINavBookmarksService::TYPE_SEPARATOR ||
+                       (aItemType == nsINavBookmarksService::TYPE_BOOKMARK &&
+                        !StringBeginsWith(aURI, "place:"_ns)))) {
+    // This is a bookmark or a separator, so we don't need to handle this if
+    // we're excluding items.
+    return NS_OK;
+  }
+
+  int32_t index;
+  nsNavHistoryResultNode* node = FindChildById(aItemId, &index);
+  // Bug 1097528.
+  // It's possible our result registered due to a previous notification, for
+  // example the Library left pane could have refreshed and replaced the
+  // right pane as a consequence. In such a case our contents are already
+  // up-to-date.  That's OK.
+  if (node && aNewParentGUID.Equals(mTargetFolderGuid) && index == aNewIndex) {
+    return NS_OK;
+  }
+  if (!node && aOldParentGUID.Equals(mTargetFolderGuid)) return NS_OK;
+
+  if (!StartIncrementalUpdate()) {
+    return NS_OK;  // entire container was refreshed for us
+  }
+
+  if (aNewParentGUID.Equals(aOldParentGUID)) {
+    // getting moved within the same folder, we don't want to do a remove and
+    // an add because that will lose your tree state.
+
+    // adjust bookmark indices
+    ReindexRange(aOldIndex + 1, INT32_MAX, -1);
+    ReindexRange(aNewIndex, INT32_MAX, 1);
+
+    MOZ_ASSERT(node, "Can't find folder that is moving!");
+    if (!node) {
+      return NS_ERROR_FAILURE;
+    }
+    MOZ_ASSERT(index < mChildren.Count(), "Invalid index!");
+    node->mBookmarkIndex = aNewIndex;
+
+    // adjust position
+    EnsureItemPosition(index);
+    return NS_OK;
+  }
+
+  // moving between two different folders, just do a remove and an add
+  nsCOMPtr<nsIURI> itemURI;
+  if (aItemType == nsINavBookmarksService::TYPE_BOOKMARK) {
+    nsresult rv = NS_NewURI(getter_AddRefs(itemURI), aURI);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  if (aOldParentGUID.Equals(mTargetFolderGuid)) {
+    OnItemRemoved(aItemId, mTargetFolderItemId, aOldIndex, aItemType, itemURI,
+                  aGUID, aOldParentGUID, aSource);
+  }
+  if (aNewParentGUID.Equals(mTargetFolderGuid)) {
+    OnItemAdded(aItemId, mTargetFolderItemId, aNewIndex, aItemType, itemURI,
+                aDateAdded, aGUID, aNewParentGUID, aSource, aTitle, aTags,
+                aFrecency, aHidden, aVisitCount, aLastVisitDate,
+                mTargetFolderItemId, mTargetFolderGuid, aTitle);
+  }
+
+  return NS_OK;
+}
+
+/**
+ * Separator nodes do not hold any data.
+ */
+nsNavHistorySeparatorResultNode::nsNavHistorySeparatorResultNode()
+    : nsNavHistoryResultNode(""_ns, ""_ns, 0, 0) {}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(nsNavHistoryResult)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsNavHistoryResult)
+  tmp->StopObservingOnUnlink();
+
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRootNode)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mObservers)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mMobilePrefObservers)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mAllBookmarksObservers)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mHistoryObservers)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRefreshParticipants)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_WEAK_REFERENCE
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsNavHistoryResult)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRootNode)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mObservers)
+  for (nsNavHistoryResult::FolderObserverList* list :
+       tmp->mBookmarkFolderObservers.Values()) {
+    for (uint32_t i = 0; i < list->Length(); ++i) {
+      NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb,
+                                         "mBookmarkFolderObservers value[i]");
+      nsNavHistoryResultNode* node = list->ElementAt(i);
+      cb.NoteXPCOMChild(node);
+    }
+  }
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMobilePrefObservers)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAllBookmarksObservers)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mHistoryObservers)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRefreshParticipants)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsNavHistoryResult)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsNavHistoryResult)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsNavHistoryResult)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsINavHistoryResult)
+  NS_INTERFACE_MAP_STATIC_AMBIGUOUS(nsNavHistoryResult)
+  NS_INTERFACE_MAP_ENTRY(nsINavHistoryResult)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+NS_INTERFACE_MAP_END
+
+nsNavHistoryResult::nsNavHistoryResult(
+    nsNavHistoryContainerResultNode* aRoot,
+    const RefPtr<nsNavHistoryQuery>& aQuery,
+    const RefPtr<nsNavHistoryQueryOptions>& aOptions)
+    : mRootNode(aRoot),
+      mQuery(aQuery),
+      mOptions(aOptions),
+      mNeedsToApplySortingMode(false),
+      mIsHistoryObserver(false),
+      mIsBookmarksObserver(false),
+      mIsMobilePrefObserver(false),
+      mBookmarkFolderObservers(64),
+      mSuppressNotifications(false),
+      mIsHistoryDetailsObserver(false),
+      mObserversWantHistoryDetails(true),
+      mBatchInProgress(0) {
+  mSortingMode = aOptions->SortingMode();
+
+  mRootNode->mResult = this;
+  MOZ_ASSERT(mRootNode->mIndentLevel == -1,
+             "Root node's indent level initialized wrong");
+  mRootNode->FillStats();
+
+  AutoTArray<PlacesEventType, 1> events;
+  events.AppendElement(PlacesEventType::Purge_caches);
+  PlacesObservers::AddListener(events, this);
+}
+
+nsNavHistoryResult::~nsNavHistoryResult() {
+  // Delete all heap-allocated bookmark folder observer arrays.
+  for (auto it = mBookmarkFolderObservers.Iter(); !it.Done(); it.Next()) {
+    delete it.Data();
+    it.Remove();
+  }
+}
+
+void nsNavHistoryResult::StopObserving() {
+  AutoTArray<PlacesEventType, 12> events;
+  events.AppendElement(PlacesEventType::Favicon_changed);
+  if (mIsBookmarksObserver) {
+    events.AppendElement(PlacesEventType::Bookmark_added);
+    events.AppendElement(PlacesEventType::Bookmark_removed);
+    events.AppendElement(PlacesEventType::Bookmark_moved);
+    events.AppendElement(PlacesEventType::Bookmark_keyword_changed);
+    events.AppendElement(PlacesEventType::Bookmark_tags_changed);
+    events.AppendElement(PlacesEventType::Bookmark_time_changed);
+    events.AppendElement(PlacesEventType::Bookmark_title_changed);
+    events.AppendElement(PlacesEventType::Bookmark_url_changed);
+    mIsBookmarksObserver = false;
+  }
+  if (mIsMobilePrefObserver) {
+    Preferences::UnregisterCallback(OnMobilePrefChangedCallback,
+                                    MOBILE_BOOKMARKS_PREF, this);
+    mIsMobilePrefObserver = false;
+  }
+  if (mIsHistoryObserver) {
+    mIsHistoryObserver = false;
+    events.AppendElement(PlacesEventType::History_cleared);
+    events.AppendElement(PlacesEventType::Page_removed);
+  }
+  if (mIsHistoryDetailsObserver) {
+    events.AppendElement(PlacesEventType::Page_visited);
+    events.AppendElement(PlacesEventType::Page_title_changed);
+    mIsHistoryDetailsObserver = false;
+  }
+
+  PlacesObservers::RemoveListener(events, this);
+}
+
+void nsNavHistoryResult::StopObservingOnUnlink() {
+  StopObserving();
+
+  AutoTArray<PlacesEventType, 1> events;
+  events.AppendElement(PlacesEventType::Purge_caches);
+  PlacesObservers::RemoveListener(events, this);
+
+  for (auto it = mBookmarkFolderObservers.Iter(); !it.Done(); it.Next()) {
+    delete it.Data();
+    it.Remove();
+  }
+}
+
+bool nsNavHistoryResult::CanSkipHistoryDetailsNotifications() const {
+  return !mObserversWantHistoryDetails &&
+         mOptions->QueryType() ==
+             nsINavHistoryQueryOptions::QUERY_TYPE_BOOKMARKS &&
+         mSortingMode != nsINavHistoryQueryOptions::SORT_BY_DATE_ASCENDING &&
+         mSortingMode != nsINavHistoryQueryOptions::SORT_BY_DATE_DESCENDING &&
+         mSortingMode !=
+             nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_ASCENDING &&
+         mSortingMode !=
+             nsINavHistoryQueryOptions::SORT_BY_VISITCOUNT_DESCENDING &&
+         mSortingMode !=
+             nsINavHistoryQueryOptions::SORT_BY_FRECENCY_ASCENDING &&
+         mSortingMode != nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING;
+}
+
+void nsNavHistoryResult::AddHistoryObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  if (!mIsHistoryObserver) {
+    mIsHistoryObserver = true;
+
+    AutoTArray<PlacesEventType, 3> events;
+    events.AppendElement(PlacesEventType::History_cleared);
+    events.AppendElement(PlacesEventType::Page_removed);
+    if (!mIsHistoryDetailsObserver) {
+      events.AppendElement(PlacesEventType::Page_visited);
+      events.AppendElement(PlacesEventType::Page_title_changed);
+      mIsHistoryDetailsObserver = true;
+    }
+    PlacesObservers::AddListener(events, this);
+  }
+  // Don't add duplicate observers.  In some case we don't unregister when
+  // children are cleared (see ClearChildren) and the next FillChildren call
+  // will try to add the observer again.
+  if (mHistoryObservers.IndexOf(aNode) == QueryObserverList::NoIndex) {
+    mHistoryObservers.AppendElement(aNode);
+  }
+}
+
+void nsNavHistoryResult::AddAllBookmarksObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  EnsureIsObservingBookmarks();
+  // Don't add duplicate observers.  In some case we don't unregister when
+  // children are cleared (see ClearChildren) and the next FillChildren call
+  // will try to add the observer again.
+  if (mAllBookmarksObservers.IndexOf(aNode) == QueryObserverList::NoIndex) {
+    mAllBookmarksObservers.AppendElement(aNode);
+  }
+}
+
+void nsNavHistoryResult::AddMobilePrefsObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  if (!mIsMobilePrefObserver) {
+    Preferences::RegisterCallback(OnMobilePrefChangedCallback,
+                                  MOBILE_BOOKMARKS_PREF, this);
+    mIsMobilePrefObserver = true;
+  }
+  // Don't add duplicate observers.  In some case we don't unregister when
+  // children are cleared (see ClearChildren) and the next FillChildren call
+  // will try to add the observer again.
+  if (mMobilePrefObservers.IndexOf(aNode) == QueryObserverList::NoIndex) {
+    mMobilePrefObservers.AppendElement(aNode);
+  }
+}
+
+void nsNavHistoryResult::AddBookmarkFolderObserver(
+    nsNavHistoryFolderResultNode* aNode, const nsACString& aFolderGUID) {
+  MOZ_ASSERT(!aFolderGUID.IsEmpty(), "aFolderGUID should not be empty");
+  EnsureIsObservingBookmarks();
+  // Don't add duplicate observers.  In some case we don't unregister when
+  // children are cleared (see ClearChildren) and the next FillChildren call
+  // will try to add the observer again.
+  FolderObserverList* list = BookmarkFolderObserversForGUID(aFolderGUID, true);
+  if (list->IndexOf(aNode) == FolderObserverList::NoIndex) {
+    list->AppendElement(aNode);
+  }
+}
+
+void nsNavHistoryResult::EnsureIsObservingBookmarks() {
+  if (mIsBookmarksObserver) {
+    return;
+  }
+  AutoTArray<PlacesEventType, 9> events;
+  events.AppendElement(PlacesEventType::Bookmark_added);
+  events.AppendElement(PlacesEventType::Bookmark_removed);
+  events.AppendElement(PlacesEventType::Bookmark_moved);
+  events.AppendElement(PlacesEventType::Bookmark_keyword_changed);
+  events.AppendElement(PlacesEventType::Bookmark_tags_changed);
+  events.AppendElement(PlacesEventType::Bookmark_time_changed);
+  events.AppendElement(PlacesEventType::Bookmark_title_changed);
+  events.AppendElement(PlacesEventType::Bookmark_url_changed);
+  // If we're not observing visits yet, also add a page-visited observer to
+  // serve onItemVisited.
+  if (!mIsHistoryObserver && !mIsHistoryDetailsObserver) {
+    events.AppendElement(PlacesEventType::Page_visited);
+    mIsHistoryDetailsObserver = true;
+  }
+  PlacesObservers::AddListener(events, this);
+  mIsBookmarksObserver = true;
+}
+
+void nsNavHistoryResult::RemoveHistoryObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  mHistoryObservers.RemoveElement(aNode);
+}
+
+void nsNavHistoryResult::RemoveAllBookmarksObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  mAllBookmarksObservers.RemoveElement(aNode);
+}
+
+void nsNavHistoryResult::RemoveMobilePrefsObserver(
+    nsNavHistoryQueryResultNode* aNode) {
+  mMobilePrefObservers.RemoveElement(aNode);
+}
+
+void nsNavHistoryResult::RemoveBookmarkFolderObserver(
+    nsNavHistoryFolderResultNode* aNode, const nsACString& aFolderGUID) {
+  MOZ_ASSERT(!aFolderGUID.IsEmpty(), "aFolderGUID should not be empty");
+  FolderObserverList* list = BookmarkFolderObserversForGUID(aFolderGUID, false);
+  if (!list) return;  // we don't even have an entry for that folder
+  list->RemoveElement(aNode);
+}
+
+nsNavHistoryResult::FolderObserverList*
+nsNavHistoryResult::BookmarkFolderObserversForGUID(
+    const nsACString& aFolderGUID, bool aCreate) {
+  FolderObserverList* list;
+  if (mBookmarkFolderObservers.Get(aFolderGUID, &list)) return list;
+  if (!aCreate) return nullptr;
+
+  // need to create a new list
+  list = new FolderObserverList;
+  mBookmarkFolderObservers.InsertOrUpdate(aFolderGUID, list);
+  return list;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::GetSortingMode(uint16_t* aSortingMode) {
+  *aSortingMode = mSortingMode;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::SetSortingMode(uint16_t aSortingMode) {
+  NS_ENSURE_STATE(mRootNode);
+
+  if (aSortingMode > nsINavHistoryQueryOptions::SORT_BY_FRECENCY_DESCENDING) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Keep everything in sync.
+  NS_ASSERTION(mOptions, "Options should always be present for a root query");
+
+  mSortingMode = aSortingMode;
+
+  // If the sorting mode changed to one requiring history details, we must
+  // ensure to start observing.
+  bool addedListener = UpdateHistoryDetailsObservers();
+
+  if (!mRootNode->mExpanded) {
+    // Need to do this later when node will be expanded.
+    mNeedsToApplySortingMode = true;
+    return NS_OK;
+  }
+
+  if (addedListener) {
+    // We must do a full refresh because the history details may be stale.
+    if (mRootNode->IsQuery()) {
+      return mRootNode->GetAsQuery()->Refresh();
+    }
+    if (mRootNode->IsFolder()) {
+      return mRootNode->GetAsFolder()->Refresh();
+    }
+  }
+
+  // Actually do sorting.
+  nsNavHistoryContainerResultNode::SortComparator comparator =
+      nsNavHistoryContainerResultNode::GetSortingComparator(aSortingMode);
+  if (comparator) {
+    nsNavHistory* history = nsNavHistory::GetHistoryService();
+    NS_ENSURE_TRUE(history, NS_ERROR_OUT_OF_MEMORY);
+    mRootNode->RecursiveSort(comparator);
+  }
+
+  NOTIFY_RESULT_OBSERVERS(this, SortingChanged(aSortingMode));
+  NOTIFY_RESULT_OBSERVERS(this, InvalidateContainer(mRootNode));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::AddObserver(nsINavHistoryResultObserver* aObserver,
+                                bool aOwnsWeak) {
+  NS_ENSURE_ARG(aObserver);
+  nsresult rv = mObservers.AppendWeakElementUnlessExists(aObserver, aOwnsWeak);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  UpdateHistoryDetailsObservers();
+
+  rv = aObserver->SetResult(this);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // If we are batching, notify a fake batch start to the observers.
+  // Not doing so would then notify a not coupled batch end.
+  if (IsBatching()) {
+    NOTIFY_RESULT_OBSERVERS(this, Batching(true));
+  }
+
+  if (!mRootNode->IsQuery() ||
+      mRootNode->GetAsQuery()->mLiveUpdate != QUERYUPDATE_NONE) {
+    // Pretty much all the views show favicons, thus observe changes to them.
+    AutoTArray<PlacesEventType, 1> events;
+    events.AppendElement(PlacesEventType::Favicon_changed);
+    PlacesObservers::AddListener(events, this);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::RemoveObserver(nsINavHistoryResultObserver* aObserver) {
+  NS_ENSURE_ARG(aObserver);
+  nsresult rv = mObservers.RemoveWeakElement(aObserver);
+  NS_ENSURE_SUCCESS(rv, rv);
+  UpdateHistoryDetailsObservers();
+  return NS_OK;
+}
+
+bool nsNavHistoryResult::UpdateHistoryDetailsObservers() {
+  bool skipHistoryDetailsNotifications = false;
+  // One observer set to true is enough to set mObserversWantHistoryDetails.
+  for (uint32_t i = 0;
+       i < mObservers.Length() && !skipHistoryDetailsNotifications; ++i) {
+    const nsCOMPtr<nsINavHistoryResultObserver>& entry =
+        mObservers.ElementAt(i).GetValue();
+    if (entry) {
+      entry->GetSkipHistoryDetailsNotifications(
+          &skipHistoryDetailsNotifications);
+    }
+  }
+
+  mObserversWantHistoryDetails = !skipHistoryDetailsNotifications;
+  // If one observer wants history details we may have to add the listener.
+  if (!CanSkipHistoryDetailsNotifications()) {
+    if (!mIsHistoryDetailsObserver) {
+      AutoTArray<PlacesEventType, 3> events;
+      events.AppendElement(PlacesEventType::Page_visited);
+      events.AppendElement(PlacesEventType::Page_title_changed);
+      events.AppendElement(PlacesEventType::Page_removed);
+      PlacesObservers::AddListener(events, this);
+      mIsHistoryDetailsObserver = true;
+      return true;
+    }
+  } else {
+    AutoTArray<PlacesEventType, 3> events;
+    events.AppendElement(PlacesEventType::Page_visited);
+    events.AppendElement(PlacesEventType::Page_title_changed);
+    events.AppendElement(PlacesEventType::Page_removed);
+    PlacesObservers::RemoveListener(events, this);
+    mIsHistoryDetailsObserver = false;
+  }
+  return false;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::GetSuppressNotifications(bool* _retval) {
+  *_retval = mSuppressNotifications;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::SetSuppressNotifications(bool aSuppressNotifications) {
+  mSuppressNotifications = aSuppressNotifications;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::GetRoot(nsINavHistoryContainerResultNode** aRoot) {
+  if (!mRootNode) {
+    MOZ_ASSERT_UNREACHABLE("Root is null");
+    *aRoot = nullptr;
+    return NS_ERROR_FAILURE;
+  }
+  RefPtr<nsNavHistoryContainerResultNode> node(mRootNode);
+  node.forget(aRoot);
+  return NS_OK;
+}
+
+void nsNavHistoryResult::requestRefresh(
+    nsNavHistoryContainerResultNode* aContainer) {
+  // Don't add twice the same container.
+  if (mRefreshParticipants.IndexOf(aContainer) ==
+      ContainerObserverList::NoIndex) {
+    mRefreshParticipants.AppendElement(aContainer);
+  }
+}
+
+// Here, it is important that we create a COPY of the observer array. Some
+// observers will requery themselves, which may cause the observer array to
+// be modified or added to.
+#define ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(_folderGUID, _functionCall) \
+  PR_BEGIN_MACRO                                                        \
+  FolderObserverList* _fol =                                            \
+      BookmarkFolderObserversForGUID(_folderGUID, false);               \
+  if (_fol) {                                                           \
+    FolderObserverList _listCopy(_fol->Clone());                        \
+    for (uint32_t _fol_i = 0; _fol_i < _listCopy.Length(); ++_fol_i) {  \
+      if (_listCopy[_fol_i]) _listCopy[_fol_i]->_functionCall;          \
+    }                                                                   \
+  }                                                                     \
+  PR_END_MACRO
+#define ENUMERATE_LIST_OBSERVERS(_listType, _functionCall, _observersList, \
+                                 _conditionCall)                           \
+  PR_BEGIN_MACRO                                                           \
+  _listType _listCopy((_observersList).Clone());                           \
+  for (uint32_t _obs_i = 0; _obs_i < _listCopy.Length(); ++_obs_i) {       \
+    if (_listCopy[_obs_i] && _listCopy[_obs_i]->_conditionCall)            \
+      _listCopy[_obs_i]->_functionCall;                                    \
+  }                                                                        \
+  PR_END_MACRO
+#define ENUMERATE_QUERY_OBSERVERS(_functionCall, _observersList,             \
+                                  _conditionCall)                            \
+  ENUMERATE_LIST_OBSERVERS(QueryObserverList, _functionCall, _observersList, \
+                           _conditionCall)
+#define ENUMERATE_ALL_BOOKMARKS_OBSERVERS(_functionCall) \
+  ENUMERATE_QUERY_OBSERVERS(_functionCall, mAllBookmarksObservers, IsQuery())
+#define ENUMERATE_HISTORY_OBSERVERS(_functionCall) \
+  ENUMERATE_QUERY_OBSERVERS(_functionCall, mHistoryObservers, IsQuery())
+#define ENUMERATE_MOBILE_PREF_OBSERVERS(_functionCall) \
+  ENUMERATE_QUERY_OBSERVERS(_functionCall, mMobilePrefObservers, IsQuery())
+#define ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(_folderGUID, _targetId,        \
+                                             _functionCall)                 \
+  PR_BEGIN_MACRO                                                            \
+  ENUMERATE_ALL_BOOKMARKS_OBSERVERS(_functionCall);                         \
+  FolderObserverList* _fol =                                                \
+      BookmarkFolderObserversForGUID(_folderGUID, false);                   \
+                                                                            \
+  /*                                                                        \
+   * Note: folder-nodes set their own bookmark observer only once they're   \
+   * opened, meaning we cannot optimize this code path for changes done to  \
+   * folder-nodes.                                                          \
+   */                                                                       \
+                                                                            \
+  for (uint32_t _fol_i = 0; _fol && _fol_i < _fol->Length(); ++_fol_i) {    \
+    RefPtr<nsNavHistoryFolderResultNode> _folder = _fol->ElementAt(_fol_i); \
+    if (_folder) {                                                          \
+      int32_t _nodeIndex;                                                   \
+      RefPtr<nsNavHistoryResultNode> _node =                                \
+          _folder->FindChildById(_targetId, &_nodeIndex);                   \
+      bool _excludeItems = _folder->mOptions->ExcludeItems();               \
+      if (_node &&                                                          \
+          (!_excludeItems || !(_node->IsURI() || _node->IsSeparator())) &&  \
+          _folder->StartIncrementalUpdate()) {                              \
+        _node->_functionCall;                                               \
+      }                                                                     \
+    }                                                                       \
+  }                                                                         \
+                                                                            \
+  PR_END_MACRO
+
+#define NOTIFY_REFRESH_PARTICIPANTS()                            \
+  PR_BEGIN_MACRO                                                 \
+  ENUMERATE_LIST_OBSERVERS(ContainerObserverList, Refresh(),     \
+                           mRefreshParticipants, IsContainer()); \
+  mRefreshParticipants.Clear();                                  \
+  PR_END_MACRO
+
+NS_IMETHODIMP
+nsNavHistoryResult::OnBeginUpdateBatch() {
+  // Since we could be observing both history and bookmarks, it's possible both
+  // notify the batch.  We can safely ignore nested calls.
+  if (++mBatchInProgress == 1) {
+    ENUMERATE_HISTORY_OBSERVERS(OnBeginUpdateBatch());
+    ENUMERATE_ALL_BOOKMARKS_OBSERVERS(OnBeginUpdateBatch());
+
+    NOTIFY_RESULT_OBSERVERS(this, Batching(true));
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNavHistoryResult::OnEndUpdateBatch() {
+  // Since we could be observing both history and bookmarks, it's possible both
+  // notify the batch.  We can safely ignore nested calls.
+  // Notice it's possible we are notified OnEndUpdateBatch more times than
+  // onBeginUpdateBatch, since the result could be created in the middle of
+  // nested batches.
+  if (--mBatchInProgress == 0) {
+    ENUMERATE_HISTORY_OBSERVERS(OnEndUpdateBatch());
+    ENUMERATE_ALL_BOOKMARKS_OBSERVERS(OnEndUpdateBatch());
+
+    NOTIFY_REFRESH_PARTICIPANTS();
+    NOTIFY_RESULT_OBSERVERS(this, Batching(false));
+  }
+
+  return NS_OK;
+}
+
+nsresult nsNavHistoryResult::OnVisit(nsIURI* aURI, int64_t aVisitId,
+                                     PRTime aTime, uint32_t aTransitionType,
+                                     const nsACString& aGUID, bool aHidden,
+                                     uint32_t aVisitCount,
+                                     const nsAString& aLastKnownTitle,
+                                     int64_t aFrecency) {
+  NS_ENSURE_ARG(aURI);
+
+  // Embed visits are never shown in our views.
+  if (aTransitionType == nsINavHistoryService::TRANSITION_EMBED) {
+    return NS_OK;
+  }
+
+  uint32_t added = 0;
+
+  ENUMERATE_HISTORY_OBSERVERS(OnVisit(aURI, aVisitId, aTime, aTransitionType,
+                                      aGUID, aHidden, aVisitCount,
+                                      aLastKnownTitle, aFrecency, &added));
+
+  // When we add visits, we don't bother telling the world that the title
+  // 'changed' from nothing to the first title we ever see for a history entry.
+  // Our consumers here might still care, though, so we have to tell them, but
+  // only for the first visit we add. Subsequent changes will get an usual
+  // ontitlechanged notification.
+  if (!aLastKnownTitle.IsVoid() && aVisitCount == 1) {
+    ENUMERATE_HISTORY_OBSERVERS(OnTitleChanged(aURI, aLastKnownTitle, aGUID));
+  }
+
+  if (!mRootNode->mExpanded) return NS_OK;
+
+  // If this visit is accepted by an overlapped container, and not all
+  // overlapped containers are visible, we should still call Refresh if the
+  // visit falls into any of them.
+  bool todayIsMissing = false;
+  uint32_t resultType = mRootNode->mOptions->ResultType();
+  if (resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY ||
+      resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY) {
+    uint32_t childCount;
+    nsresult rv = mRootNode->GetChildCount(&childCount);
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (childCount) {
+      nsCOMPtr<nsINavHistoryResultNode> firstChild;
+      rv = mRootNode->GetChild(0, getter_AddRefs(firstChild));
+      NS_ENSURE_SUCCESS(rv, rv);
+      nsAutoCString title;
+      rv = firstChild->GetTitle(title);
+      NS_ENSURE_SUCCESS(rv, rv);
+      nsNavHistory* history = nsNavHistory::GetHistoryService();
+      NS_ENSURE_TRUE(history, NS_OK);
+      nsAutoCString todayLabel;
+      history->GetStringFromName("finduri-AgeInDays-is-0", todayLabel);
+      todayIsMissing = !todayLabel.Equals(title);
+    }
+  }
+
+  if (!added || todayIsMissing) {
+    // None of registered query observers has accepted our URI.  This means,
+    // that a matching query either was not expanded or it does not exist.
+    if (resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_QUERY ||
+        resultType == nsINavHistoryQueryOptions::RESULTS_AS_DATE_SITE_QUERY) {
+      // If the visit falls into the Today bucket and the bucket exists, it was
+      // just not expanded, thus there's no reason to update.
+      int64_t beginOfToday = nsNavHistory::NormalizeTime(
+          nsINavHistoryQuery::TIME_RELATIVE_TODAY, 0);
+      if (todayIsMissing || aTime < beginOfToday) {
+        (void)mRootNode->GetAsQuery()->Refresh();
+      }
+      return NS_OK;
+    }
+
+    if (resultType == nsINavHistoryQueryOptions::RESULTS_AS_SITE_QUERY) {
+      (void)mRootNode->GetAsQuery()->Refresh();
+      return NS_OK;
+    }
+
+    // We are result of a folder node, then we should run through history
+    // observers that are containers queries and refresh them.
+    // We use a copy of the observers array since requerying could potentially
+    // cause changes to the array.
+    ENUMERATE_QUERY_OBSERVERS(Refresh(), mHistoryObservers,
+                              IsContainersQuery());
+
+    // Also notify onItemVisited to bookmark folder observers, that are not
+    // observing history.
+    if (!mIsHistoryObserver && mRootNode->IsFolder()) {
+      nsAutoCString spec;
+      nsresult rv = aURI->GetSpec(spec);
+      NS_ENSURE_SUCCESS(rv, rv);
+      // Find all the folders containing the visited URI, and notify them.
+      nsCOMArray<nsNavHistoryResultNode> nodes;
+      mRootNode->RecursiveFindURIs(true, mRootNode, spec, &nodes);
+      for (int32_t i = 0; i < nodes.Count(); ++i) {
+        nsNavHistoryResultNode* node = nodes[i];
+        ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(
+            node->mParent->mBookmarkGuid,
+            OnItemVisited(aURI, aVisitId, aTime, aFrecency));
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+void nsNavHistoryResult::OnIconChanged(nsIURI* aURI, nsIURI* aFaviconURI,
+                                       const nsACString& aGUID) {
+  if (!mRootNode->mExpanded) {
+    return;
+  }
+  // Find all nodes for the given URI and update them.
+  nsAutoCString spec;
+  if (NS_SUCCEEDED(aURI->GetSpec(spec))) {
+    bool onlyOneEntry =
+        mOptions->QueryType() ==
+            nsINavHistoryQueryOptions::QUERY_TYPE_HISTORY &&
+        mOptions->ResultType() == nsINavHistoryQueryOptions::RESULTS_AS_URI;
+    mRootNode->UpdateURIs(true, onlyOneEntry, false, spec, setFaviconCallback,
+                          nullptr);
+  }
+}
+
+bool nsNavHistoryResult::IsBulkPageRemovedEvent(
+    const PlacesEventSequence& aEvents) {
+  if (IsBatching() || aEvents.Length() <= MAX_PAGE_REMOVES_BEFORE_REFRESH) {
+    return false;
+  }
+  for (const auto& event : aEvents) {
+    if (event->Type() != PlacesEventType::Page_removed) return false;
+  }
+  return true;
+}
+
+void nsNavHistoryResult::HandlePlacesEvent(const PlacesEventSequence& aEvents) {
+  if (IsBulkPageRemovedEvent(aEvents)) {
+    ENUMERATE_HISTORY_OBSERVERS(Refresh());
+    return;
+  }
+
+  for (const auto& event : aEvents) {
+    switch (event->Type()) {
+      case PlacesEventType::Favicon_changed: {
+        const dom::PlacesFavicon* faviconEvent = event->AsPlacesFavicon();
+        if (NS_WARN_IF(!faviconEvent)) {
+          continue;
+        }
+        nsCOMPtr<nsIURI> uri, faviconUri;
+        if (NS_WARN_IF(NS_FAILED(
+                NS_NewURI(getter_AddRefs(uri), faviconEvent->mUrl)))) {
+          continue;
+        }
+        if (NS_WARN_IF(NS_FAILED(NS_NewURI(getter_AddRefs(faviconUri),
+                                           faviconEvent->mFaviconUrl)))) {
+          continue;
+        }
+        OnIconChanged(uri, faviconUri, faviconEvent->mPageGuid);
+        break;
+      }
+      case PlacesEventType::Page_visited: {
+        const dom::PlacesVisit* visit = event->AsPlacesVisit();
+        if (NS_WARN_IF(!visit)) {
+          continue;
+        }
+
+        nsCOMPtr<nsIURI> uri;
+        if (NS_WARN_IF(
+                NS_FAILED(NS_NewURI(getter_AddRefs(uri), visit->mUrl)))) {
+          continue;
+        }
+        OnVisit(uri, static_cast<int64_t>(visit->mVisitId),
+                static_cast<PRTime>(visit->mVisitTime * 1000),
+                visit->mTransitionType, visit->mPageGuid, visit->mHidden,
+                visit->mVisitCount, visit->mLastKnownTitle, visit->mFrecency);
+        break;
+      }
+      case PlacesEventType::Bookmark_added: {
+        const dom::PlacesBookmarkAddition* item =
+            event->AsPlacesBookmarkAddition();
+        if (NS_WARN_IF(!item)) {
+          continue;
+        }
+
+        nsCOMPtr<nsIURI> uri;
+        if (item->mItemType == nsINavBookmarksService::TYPE_BOOKMARK) {
+          if (NS_WARN_IF(
+                  NS_FAILED(NS_NewURI(getter_AddRefs(uri), item->mUrl)))) {
+            continue;
+          }
+        }
+
+        ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(
+            item->mParentGuid,
+            OnItemAdded(item->mId, item->mParentId, item->mIndex,
+                        item->mItemType, uri, item->mDateAdded * 1000,
+                        item->mGuid, item->mParentGuid, item->mSource,
+                        NS_ConvertUTF16toUTF8(item->mTitle), item->mTags,
+                        item->mFrecency, item->mHidden, item->mVisitCount,
+                        item->mLastVisitDate.IsNull()
+                            ? 0
+                            : item->mLastVisitDate.Value() * 1000,
+                        item->mTargetFolderItemId, item->mTargetFolderGuid,
+                        NS_ConvertUTF16toUTF8(item->mTargetFolderTitle)));
+        ENUMERATE_HISTORY_OBSERVERS(
+            OnItemAdded(item->mId, item->mParentId, item->mIndex,
+                        item->mItemType, uri, item->mDateAdded * 1000,
+                        item->mGuid, item->mParentGuid, item->mSource));
+        ENUMERATE_ALL_BOOKMARKS_OBSERVERS(
+            OnItemAdded(item->mId, item->mParentId, item->mIndex,
+                        item->mItemType, uri, item->mDateAdded * 1000,
+                        item->mGuid, item->mParentGuid, item->mSource));
+        break;
+      }
+      case PlacesEventType::Bookmark_removed: {
+        const dom::PlacesBookmarkRemoved* item =
+            event->AsPlacesBookmarkRemoved();
+        if (NS_WARN_IF(!item)) {
+          continue;
+        }
+
+        nsCOMPtr<nsIURI> uri;
+
+        if (item->mIsDescendantRemoval) {
+          continue;
+        }
+        ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(
+            item->mParentGuid,
+            OnItemRemoved(item->mId, item->mParentId, item->mIndex,
+                          item->mItemType, uri, item->mGuid, item->mParentGuid,
+                          item->mSource));
+        ENUMERATE_ALL_BOOKMARKS_OBSERVERS(OnItemRemoved(
+            item->mId, item->mParentId, item->mIndex, item->mItemType, uri,
+            item->mGuid, item->mParentGuid, item->mSource));
+        ENUMERATE_HISTORY_OBSERVERS(OnItemRemoved(
+            item->mId, item->mParentId, item->mIndex, item->mItemType, uri,
+            item->mGuid, item->mParentGuid, item->mSource));
+        break;
+      }
+      case PlacesEventType::Bookmark_moved: {
+        const dom::PlacesBookmarkMoved* item = event->AsPlacesBookmarkMoved();
+        if (NS_WARN_IF(!item)) {
+          continue;
+        }
+
+        NS_ConvertUTF16toUTF8 url(item->mUrl);
+
+        ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(
+            item->mOldParentGuid,
+            OnItemMoved(item->mId, item->mOldIndex, item->mIndex,
+                        item->mItemType, item->mGuid, item->mOldParentGuid,
+                        item->mParentGuid, item->mSource, url,
+                        NS_ConvertUTF16toUTF8(item->mTitle), item->mTags,
+                        item->mFrecency, item->mHidden, item->mVisitCount,
+                        item->mLastVisitDate.IsNull()
+                            ? 0
+                            : item->mLastVisitDate.Value() * 1000,
+                        item->mDateAdded * 1000));
+        if (!item->mParentGuid.Equals(item->mOldParentGuid)) {
+          ENUMERATE_BOOKMARK_FOLDER_OBSERVERS(
+              item->mParentGuid,
+              OnItemMoved(item->mId, item->mOldIndex, item->mIndex,
+                          item->mItemType, item->mGuid, item->mOldParentGuid,
+                          item->mParentGuid, item->mSource, url,
+                          NS_ConvertUTF16toUTF8(item->mTitle), item->mTags,
+                          item->mFrecency, item->mHidden, item->mVisitCount,
+                          item->mLastVisitDate.IsNull()
+                              ? 0
+                              : item->mLastVisitDate.Value() * 1000,
+                          item->mDateAdded * 1000));
+        }
+        ENUMERATE_ALL_BOOKMARKS_OBSERVERS(
+            OnItemMoved(item->mId, item->mOldIndex, item->mIndex,
+                        item->mItemType, item->mGuid, item->mOldParentGuid,
+                        item->mParentGuid, item->mSource, url));
+        ENUMERATE_HISTORY_OBSERVERS(
+            OnItemMoved(item->mId, item->mOldIndex, item->mIndex,
+                        item->mItemType, item->mGuid, item->mOldParentGuid,
+                        item->mParentGuid, item->mSource, url));
+        break;
+      }
+      case PlacesEventType::Bookmark_keyword_changed: {
+        const dom::PlacesBookmarkKeyword* keywordEvent =
+            event->AsPlacesBookmarkKeyword();
+        if (NS_WARN_IF(!keywordEvent)) {
+          continue;
+        }
+        ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(
+            keywordEvent->mParentGuid, keywordEvent->mId,
+            OnItemKeywordChanged(keywordEvent->mId, keywordEvent->mKeyword));
+        break;
+      }
+      case PlacesEventType::Bookmark_tags_changed: {
+        const dom::PlacesBookmarkTags* tagsEvent =
+            event->AsPlacesBookmarkTags();
+        if (NS_WARN_IF(!tagsEvent)) {
+          continue;
+        }
+
+        nsString tags;
+        tagsEvent->mTags.Length()
+            ? tags.Assign(StringJoin(u","_ns, tagsEvent->mTags))
+            : tags.SetIsVoid(true);
+
+        ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(
+            tagsEvent->mParentGuid, tagsEvent->mId,
+            OnItemTagsChanged(tagsEvent->mId, tagsEvent->mUrl, tags));
+        break;
+      }
+      case PlacesEventType::Bookmark_time_changed: {
+        const dom::PlacesBookmarkTime* timeEvent =
+            event->AsPlacesBookmarkTime();
+        if (NS_WARN_IF(!timeEvent)) {
+          continue;
+        }
+        ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(
+            timeEvent->mParentGuid, timeEvent->mId,
+            OnItemTimeChanged(timeEvent->mId, timeEvent->mGuid,
+                              timeEvent->mDateAdded * 1000,
+                              timeEvent->mLastModified * 1000));
+        break;
+      }
+      case PlacesEventType::Bookmark_title_changed: {
+        const dom::PlacesBookmarkTitle* titleEvent =
+            event->AsPlacesBookmarkTitle();
+        if (NS_WARN_IF(!titleEvent)) {
+          continue;
+        }
+
+        NS_ConvertUTF16toUTF8 title(titleEvent->mTitle);
+        ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(
+            titleEvent->mParentGuid, titleEvent->mId,
+            OnItemTitleChanged(titleEvent->mId, titleEvent->mGuid, title,
+                               titleEvent->mLastModified * 1000));
+        break;
+      }
+      case PlacesEventType::Bookmark_url_changed: {
+        const dom::PlacesBookmarkUrl* urlEvent = event->AsPlacesBookmarkUrl();
+        if (NS_WARN_IF(!urlEvent)) {
+          continue;
+        }
+
+        NS_ConvertUTF16toUTF8 url(urlEvent->mUrl);
+        ENUMERATE_BOOKMARK_CHANGED_OBSERVERS(
+            urlEvent->mParentGuid, urlEvent->mId,
+            OnItemUrlChanged(urlEvent->mId, urlEvent->mGuid, url,
+                             urlEvent->mLastModified * 1000));
+        break;
+      }
+      case PlacesEventType::Page_title_changed: {
+        const PlacesVisitTitle* titleEvent = event->AsPlacesVisitTitle();
+        if (NS_WARN_IF(!titleEvent)) {
+          continue;
+        }
+
+        nsCOMPtr<nsIURI> uri;
+        if (NS_WARN_IF(
+                NS_FAILED(NS_NewURI(getter_AddRefs(uri), titleEvent->mUrl)))) {
+          continue;
+        }
+
+        ENUMERATE_HISTORY_OBSERVERS(
+            OnTitleChanged(uri, titleEvent->mTitle, titleEvent->mPageGuid));
+        break;
+      }
+      case PlacesEventType::History_cleared: {
+        ENUMERATE_HISTORY_OBSERVERS(OnClearHistory());
+        break;
+      }
+      case PlacesEventType::Page_removed: {
+        const PlacesVisitRemoved* removeEvent = event->AsPlacesVisitRemoved();
+        if (NS_WARN_IF(!removeEvent)) {
+          continue;
+        }
+
+        nsCOMPtr<nsIURI> uri;
+        if (NS_WARN_IF(
+                NS_FAILED(NS_NewURI(getter_AddRefs(uri), removeEvent->mUrl)))) {
+          continue;
+        }
+
+        if (removeEvent->mIsRemovedFromStore) {
+          ENUMERATE_HISTORY_OBSERVERS(OnPageRemovedFromStore(
+              uri, removeEvent->mPageGuid, removeEvent->mReason));
+        } else {
+          ENUMERATE_HISTORY_OBSERVERS(
+              OnPageRemovedVisits(uri, removeEvent->mIsPartialVisistsRemoval,
+                                  removeEvent->mPageGuid, removeEvent->mReason,
+                                  removeEvent->mTransitionType));
+
+          if (!removeEvent->mIsPartialVisistsRemoval && mRootNode) {
+            mRootNode->OnVisitsRemoved(uri);
+          }
+        }
+
+        break;
+      }
+      case PlacesEventType::Purge_caches: {
+        mRootNode->Refresh();
+        break;
+      }
+      default: {
+        MOZ_ASSERT_UNREACHABLE(
+            "Receive notification of a type not subscribed to.");
+      }
+    }
+  }
+}
+
+void nsNavHistoryResult::OnMobilePrefChanged() {
+  ENUMERATE_MOBILE_PREF_OBSERVERS(
+      OnMobilePrefChanged(Preferences::GetBool(MOBILE_BOOKMARKS_PREF, false)));
+}
+
+void nsNavHistoryResult::OnMobilePrefChangedCallback(const char* prefName,
+                                                     void* self) {
+  MOZ_ASSERT(!strcmp(prefName, MOBILE_BOOKMARKS_PREF),
+             "We only expected Mobile Bookmarks pref change.");
+
+  static_cast<nsNavHistoryResult*>(self)->OnMobilePrefChanged();
+}
diff --git a/toolkit/components/places/nsNavHistoryResult.h b/toolkit/components/places/nsNavHistoryResult.h
new file mode 100644
index 0000000000..714b81a2ea
--- /dev/null
+++ b/toolkit/components/places/nsNavHistoryResult.h
@@ -0,0 +1,849 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * The definitions of objects that make up a history query result set. This file
+ * should only be included by nsNavHistory.h, include that if you want these
+ * classes.
+ */
+
+#ifndef nsNavHistoryResult_h_
+#define nsNavHistoryResult_h_
+
+#include "INativePlacesEventCallback.h"
+#include "nsCOMArray.h"
+#include "nsTArray.h"
+#include "nsMaybeWeakPtr.h"
+#include "nsInterfaceHashtable.h"
+#include "nsINavHistoryService.h"
+#include "nsTHashMap.h"
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/storage.h"
+#include "Helpers.h"
+
+class nsNavHistory;
+class nsNavHistoryQuery;
+class nsNavHistoryQueryOptions;
+
+class nsNavHistoryContainerResultNode;
+class nsNavHistoryFolderResultNode;
+class nsNavHistoryQueryResultNode;
+
+/**
+ * hashkey wrapper using int64_t KeyType
+ *
+ * @see nsTHashtable::EntryType for specification
+ *
+ * This just truncates the 64-bit int to a 32-bit one for using a hash number.
+ * It is used for bookmark folder IDs, which should be way less than 2^32.
+ */
+class nsTrimInt64HashKey : public PLDHashEntryHdr {
+ public:
+  using KeyType = const int64_t&;
+  using KeyTypePointer = const int64_t*;
+
+  explicit nsTrimInt64HashKey(KeyTypePointer aKey) : mValue(*aKey) {}
+  nsTrimInt64HashKey(const nsTrimInt64HashKey& toCopy)
+      : mValue(toCopy.mValue) {}
+  ~nsTrimInt64HashKey() = default;
+
+  KeyType GetKey() const { return mValue; }
+  bool KeyEquals(KeyTypePointer aKey) const { return *aKey == mValue; }
+
+  static KeyTypePointer KeyToPointer(KeyType aKey) { return &aKey; }
+  static PLDHashNumber HashKey(KeyTypePointer aKey) {
+    return static_cast<uint32_t>((*aKey) & UINT32_MAX);
+  }
+  enum { ALLOW_MEMMOVE = true };
+
+ private:
+  const int64_t mValue;
+};
+
+// nsNavHistoryResult
+//
+//    nsNavHistory creates this object and fills in mChildren (by getting
+//    it through GetTopLevel()). Then FilledAllResults() is called to finish
+//    object initialization.
+
+#define NS_NAVHISTORYRESULT_IID                      \
+  {                                                  \
+    0x455d1d40, 0x1b9b, 0x40e6, {                    \
+      0xa6, 0x41, 0x8b, 0xb7, 0xe8, 0x82, 0x23, 0x87 \
+    }                                                \
+  }
+
+class nsNavHistoryResult final
+    : public nsSupportsWeakReference,
+      public nsINavHistoryResult,
+      public mozilla::places::INativePlacesEventCallback {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_NAVHISTORYRESULT_IID)
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_NSINAVHISTORYRESULT
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsNavHistoryResult,
+                                           nsINavHistoryResult)
+
+  void AddHistoryObserver(nsNavHistoryQueryResultNode* aNode);
+  void AddBookmarkFolderObserver(nsNavHistoryFolderResultNode* aNode,
+                                 const nsACString& aFolderGUID);
+  void AddAllBookmarksObserver(nsNavHistoryQueryResultNode* aNode);
+  void AddMobilePrefsObserver(nsNavHistoryQueryResultNode* aNode);
+  void RemoveHistoryObserver(nsNavHistoryQueryResultNode* aNode);
+  void RemoveBookmarkFolderObserver(nsNavHistoryFolderResultNode* aNode,
+                                    const nsACString& aFolderGUID);
+  void RemoveAllBookmarksObserver(nsNavHistoryQueryResultNode* aNode);
+  void RemoveMobilePrefsObserver(nsNavHistoryQueryResultNode* aNode);
+  void StopObserving();
+  void EnsureIsObservingBookmarks();
+
+  nsresult OnVisit(nsIURI* aURI, int64_t aVisitId, PRTime aTime,
+                   uint32_t aTransitionType, const nsACString& aGUID,
+                   bool aHidden, uint32_t aVisitCount,
+                   const nsAString& aLastKnownTitle, int64_t aFrecency);
+
+  void OnIconChanged(nsIURI* aURI, nsIURI* aFaviconURI,
+                     const nsACString& aGUID);
+
+  explicit nsNavHistoryResult(nsNavHistoryContainerResultNode* aRoot,
+                              const RefPtr<nsNavHistoryQuery>& aQuery,
+                              const RefPtr<nsNavHistoryQueryOptions>& aOptions);
+
+  RefPtr<nsNavHistoryContainerResultNode> mRootNode;
+
+  RefPtr<nsNavHistoryQuery> mQuery;
+  RefPtr<nsNavHistoryQueryOptions> mOptions;
+
+  // One of nsNavHistoryQueryOptions.SORY_BY_* This is initialized to
+  // mOptions.sortingMode, but may be overridden if the user clicks on one of
+  // the columns.
+  uint16_t mSortingMode;
+  // If root node is closed and we try to apply a sortingMode, it would not
+  // work.  So we will apply it when the node will be reopened and populated.
+  // This var states the fact we need to apply sortingMode in such a situation.
+  bool mNeedsToApplySortingMode;
+
+  // node observers
+  bool mIsHistoryObserver;
+  bool mIsBookmarksObserver;
+  bool mIsMobilePrefObserver;
+
+  using QueryObserverList = nsTArray<RefPtr<nsNavHistoryQueryResultNode>>;
+  QueryObserverList mHistoryObservers;
+  QueryObserverList mAllBookmarksObservers;
+  QueryObserverList mMobilePrefObservers;
+
+  using FolderObserverList = nsTArray<RefPtr<nsNavHistoryFolderResultNode>>;
+  nsTHashMap<nsCStringHashKey, FolderObserverList*> mBookmarkFolderObservers;
+  FolderObserverList* BookmarkFolderObserversForGUID(
+      const nsACString& aFolderGUID, bool aCreate);
+
+  using ContainerObserverList =
+      nsTArray<RefPtr<nsNavHistoryContainerResultNode>>;
+
+  void RecursiveExpandCollapse(nsNavHistoryContainerResultNode* aContainer,
+                               bool aExpand);
+
+  void InvalidateTree();
+
+  nsMaybeWeakPtrArray<nsINavHistoryResultObserver> mObservers;
+  bool mSuppressNotifications;
+
+  // Tracks whether observers for history details were added.
+  bool mIsHistoryDetailsObserver;
+  // Tracks whether any result observer is interested in history details
+  // updates.
+  bool mObserversWantHistoryDetails;
+  /**
+   *  Updates mObserversWantHistoryDetails when observers are added/removed.
+   *  @returns Whether we started observing for history changes.
+   */
+  bool UpdateHistoryDetailsObservers();
+  // Whether NodeHistoryDetailsChanged can be skipped.
+  bool CanSkipHistoryDetailsNotifications() const;
+
+  ContainerObserverList mRefreshParticipants;
+  void requestRefresh(nsNavHistoryContainerResultNode* aContainer);
+
+  void HandlePlacesEvent(const PlacesEventSequence& aEvents) override;
+
+  // Optimisation: refreshing containers is much faster than incremental
+  // updates when handling multiple Page_removed events.
+  bool IsBulkPageRemovedEvent(const PlacesEventSequence& aEvents);
+
+  void OnMobilePrefChanged();
+
+  bool IsBatching() const { return mBatchInProgress > 0; };
+
+  static void OnMobilePrefChangedCallback(const char* prefName, void* self);
+
+ protected:
+  virtual ~nsNavHistoryResult();
+
+ private:
+  // Number of batch processes currently running. IsBatching() returns true if
+  // this value is greater than or equal to 1. Also, when this value changes to
+  // 1 from 0, batching() in nsINavHistoryResultObserver is called with
+  // parameter as true, when changes to 0, that means finishing all batch
+  // processes, batching() is called with false.
+  uint32_t mBatchInProgress;
+
+  // Stop all observers upon unlinking.
+  void StopObservingOnUnlink();
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsNavHistoryResult, NS_NAVHISTORYRESULT_IID)
+
+// nsNavHistoryResultNode
+//
+//    This is the base class for every node in a result set. The result itself
+//    is a node (nsNavHistoryResult inherits from this), as well as every
+//    leaf and branch on the tree.
+
+#define NS_NAVHISTORYRESULTNODE_IID                  \
+  {                                                  \
+    0x54b61d38, 0x57c1, 0x11da, {                    \
+      0x95, 0xb8, 0x00, 0x13, 0x21, 0xc9, 0xf6, 0x9e \
+    }                                                \
+  }
+
+// These are all the simple getters, they can be used for the result node
+// implementation and all subclasses. More complex are GetIcon, GetParent
+// (which depends on the definition of container result node), and GetUri
+// (which is overridded for lazy construction for some containers).
+#define NS_IMPLEMENT_SIMPLE_RESULTNODE                         \
+  NS_IMETHOD GetTitle(nsACString& aTitle) override {           \
+    aTitle = mTitle;                                           \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetAccessCount(uint32_t* aAccessCount) override { \
+    *aAccessCount = mAccessCount;                              \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetTime(PRTime* aTime) override {                 \
+    *aTime = mTime;                                            \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetIndentLevel(int32_t* aIndentLevel) override {  \
+    *aIndentLevel = mIndentLevel;                              \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetBookmarkIndex(int32_t* aIndex) override {      \
+    *aIndex = mBookmarkIndex;                                  \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetDateAdded(PRTime* aDateAdded) override {       \
+    *aDateAdded = mDateAdded;                                  \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetLastModified(PRTime* aLastModified) override { \
+    *aLastModified = mLastModified;                            \
+    return NS_OK;                                              \
+  }                                                            \
+  NS_IMETHOD GetItemId(int64_t* aId) override {                \
+    *aId = mItemId;                                            \
+    return NS_OK;                                              \
+  }
+
+// This is used by the base classes instead of
+// NS_FORWARD_NSINAVHISTORYRESULTNODE(nsNavHistoryResultNode) because they
+// need to redefine GetType and GetUri rather than forwarding them. This
+// implements all the simple getters instead of forwarding because they are so
+// short and we can save a virtual function call.
+//
+// (GetUri is redefined only by QueryResultNode and FolderResultNode because
+// the query might not necessarily be parsed. The rest just return the node's
+// buffer.)
+#define NS_FORWARD_COMMON_RESULTNODE_TO_BASE                                  \
+  NS_IMPLEMENT_SIMPLE_RESULTNODE                                              \
+  NS_IMETHOD GetIcon(nsACString& aIcon) override {                            \
+    return nsNavHistoryResultNode::GetIcon(aIcon);                            \
+  }                                                                           \
+  NS_IMETHOD GetParent(nsINavHistoryContainerResultNode** aParent) override { \
+    return nsNavHistoryResultNode::GetParent(aParent);                        \
+  }                                                                           \
+  NS_IMETHOD GetParentResult(nsINavHistoryResult** aResult) override {        \
+    return nsNavHistoryResultNode::GetParentResult(aResult);                  \
+  }                                                                           \
+  NS_IMETHOD GetTags(nsAString& aTags) override {                             \
+    return nsNavHistoryResultNode::GetTags(aTags);                            \
+  }                                                                           \
+  NS_IMETHOD GetPageGuid(nsACString& aPageGuid) override {                    \
+    return nsNavHistoryResultNode::GetPageGuid(aPageGuid);                    \
+  }                                                                           \
+  NS_IMETHOD GetBookmarkGuid(nsACString& aBookmarkGuid) override {            \
+    return nsNavHistoryResultNode::GetBookmarkGuid(aBookmarkGuid);            \
+  }                                                                           \
+  NS_IMETHOD GetVisitId(int64_t* aVisitId) override {                         \
+    return nsNavHistoryResultNode::GetVisitId(aVisitId);                      \
+  }                                                                           \
+  NS_IMETHOD GetVisitType(uint32_t* aVisitType) override {                    \
+    return nsNavHistoryResultNode::GetVisitType(aVisitType);                  \
+  }
+
+class nsNavHistoryResultNode : public nsINavHistoryResultNode {
+ public:
+  nsNavHistoryResultNode(const nsACString& aURI, const nsACString& aTitle,
+                         uint32_t aAccessCount, PRTime aTime);
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_NAVHISTORYRESULTNODE_IID)
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(nsNavHistoryResultNode)
+
+  NS_IMPLEMENT_SIMPLE_RESULTNODE
+  NS_IMETHOD GetIcon(nsACString& aIcon) override;
+  NS_IMETHOD GetParent(nsINavHistoryContainerResultNode** aParent) override;
+  NS_IMETHOD GetParentResult(nsINavHistoryResult** aResult) override;
+  NS_IMETHOD GetType(uint32_t* type) override {
+    *type = nsNavHistoryResultNode::RESULT_TYPE_URI;
+    return NS_OK;
+  }
+  NS_IMETHOD GetUri(nsACString& aURI) override {
+    aURI = mURI;
+    return NS_OK;
+  }
+  NS_IMETHOD GetTags(nsAString& aTags) override;
+  NS_IMETHOD GetPageGuid(nsACString& aPageGuid) override;
+  NS_IMETHOD GetBookmarkGuid(nsACString& aBookmarkGuid) override;
+  NS_IMETHOD GetVisitId(int64_t* aVisitId) override;
+  NS_IMETHOD GetVisitType(uint32_t* aVisitType) override;
+
+  virtual void OnRemoving();
+
+  nsresult OnItemKeywordChanged(int64_t aItemId, const nsACString& aKeyword);
+  nsresult OnItemTagsChanged(int64_t aItemId, const nsAString& aURL,
+                             const nsAString& aTags);
+  nsresult OnItemTimeChanged(int64_t aItemId, const nsACString& aGUID,
+                             PRTime aDateAdded, PRTime aLastModified);
+  nsresult OnItemTitleChanged(int64_t aItemId, const nsACString& aGUID,
+                              const nsACString& aTitle, PRTime aLastModified);
+  nsresult OnItemUrlChanged(int64_t aItemId, const nsACString& aGUID,
+                            const nsACString& aURL, PRTime aLastModified);
+
+  virtual nsresult OnMobilePrefChanged(bool newValue) { return NS_OK; };
+
+  nsresult OnVisitsRemoved();
+
+ protected:
+  virtual ~nsNavHistoryResultNode() = default;
+
+ public:
+  nsNavHistoryResult* GetResult();
+  void SetTags(const nsAString& aTags);
+
+  // These functions test the type. We don't use a virtual function since that
+  // would take a vtable slot for every one of (potentially very many) nodes.
+  // Note that GetType() already has a vtable slot because its on the iface.
+  bool IsTypeContainer(uint32_t type) {
+    return type == nsINavHistoryResultNode::RESULT_TYPE_QUERY ||
+           type == nsINavHistoryResultNode::RESULT_TYPE_FOLDER ||
+           type == nsINavHistoryResultNode::RESULT_TYPE_FOLDER_SHORTCUT;
+  }
+  bool IsContainer() {
+    uint32_t type;
+    GetType(&type);
+    return IsTypeContainer(type);
+  }
+  static bool IsTypeURI(uint32_t type) {
+    return type == nsINavHistoryResultNode::RESULT_TYPE_URI;
+  }
+  bool IsURI() {
+    uint32_t type;
+    GetType(&type);
+    return IsTypeURI(type);
+  }
+  static bool IsTypeFolder(uint32_t type) {
+    return type == nsINavHistoryResultNode::RESULT_TYPE_FOLDER ||
+           type == nsINavHistoryResultNode::RESULT_TYPE_FOLDER_SHORTCUT;
+  }
+  bool IsFolder() {
+    uint32_t type;
+    GetType(&type);
+    return IsTypeFolder(type);
+  }
+  static bool IsTypeQuery(uint32_t type) {
+    return type == nsINavHistoryResultNode::RESULT_TYPE_QUERY;
+  }
+  bool IsQuery() {
+    uint32_t type;
+    GetType(&type);
+    return IsTypeQuery(type);
+  }
+  bool IsSeparator() {
+    uint32_t type;
+    GetType(&type);
+    return type == nsINavHistoryResultNode::RESULT_TYPE_SEPARATOR;
+  }
+  nsNavHistoryContainerResultNode* GetAsContainer() {
+    NS_ASSERTION(IsContainer(), "Not a container");
+    return reinterpret_cast<nsNavHistoryContainerResultNode*>(this);
+  }
+  nsNavHistoryFolderResultNode* GetAsFolder() {
+    NS_ASSERTION(IsFolder(), "Not a folder");
+    return reinterpret_cast<nsNavHistoryFolderResultNode*>(this);
+  }
+  nsNavHistoryQueryResultNode* GetAsQuery() {
+    NS_ASSERTION(IsQuery(), "Not a query");
+    return reinterpret_cast<nsNavHistoryQueryResultNode*>(this);
+  }
+
+  RefPtr<nsNavHistoryContainerResultNode> mParent;
+  nsCString mURI;  // not necessarily valid for containers, call GetUri
+  nsCString mTitle;
+  nsString mTags;
+  uint32_t mAccessCount;
+  int64_t mTime;
+  int32_t mBookmarkIndex;
+  int64_t mItemId;
+  int64_t mVisitId;
+  PRTime mDateAdded;
+  PRTime mLastModified;
+
+  // The indent level of this node. The root node will have a value of -1.  The
+  // root's children will have a value of 0, and so on.
+  int32_t mIndentLevel;
+
+  // Frecency of the page.  Valid only for URI nodes.
+  int64_t mFrecency;
+
+  // Hidden status of the page.  Valid only for URI nodes.
+  bool mHidden;
+
+  // Transition type used when this node represents a single visit.
+  uint32_t mTransitionType;
+
+  // Unique Id of the page.
+  nsCString mPageGuid;
+
+  // Unique Id of the bookmark.
+  nsCString mBookmarkGuid;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsNavHistoryResultNode,
+                              NS_NAVHISTORYRESULTNODE_IID)
+
+// nsNavHistoryContainerResultNode
+//
+//    This is the base class for all nodes that can have children. It is
+//    overridden for nodes that are dynamically populated such as queries and
+//    folders. It is used directly for simple containers such as host groups
+//    in history views.
+
+// derived classes each provide their own implementation of has children and
+// forward the rest to us using this macro
+#define NS_FORWARD_CONTAINERNODE_EXCEPT_HASCHILDREN                           \
+  NS_IMETHOD GetState(uint16_t* _state) override {                            \
+    return nsNavHistoryContainerResultNode::GetState(_state);                 \
+  }                                                                           \
+  NS_IMETHOD GetContainerOpen(bool* aContainerOpen) override {                \
+    return nsNavHistoryContainerResultNode::GetContainerOpen(aContainerOpen); \
+  }                                                                           \
+  NS_IMETHOD SetContainerOpen(bool aContainerOpen) override {                 \
+    return nsNavHistoryContainerResultNode::SetContainerOpen(aContainerOpen); \
+  }                                                                           \
+  NS_IMETHOD GetChildCount(uint32_t* aChildCount) override {                  \
+    return nsNavHistoryContainerResultNode::GetChildCount(aChildCount);       \
+  }                                                                           \
+  NS_IMETHOD GetChild(uint32_t index, nsINavHistoryResultNode** _retval)      \
+      override {                                                              \
+    return nsNavHistoryContainerResultNode::GetChild(index, _retval);         \
+  }                                                                           \
+  NS_IMETHOD GetChildIndex(nsINavHistoryResultNode* aNode, uint32_t* _retval) \
+      override {                                                              \
+    return nsNavHistoryContainerResultNode::GetChildIndex(aNode, _retval);    \
+  }
+
+#define NS_NAVHISTORYCONTAINERRESULTNODE_IID         \
+  {                                                  \
+    0x6e3bf8d3, 0x22aa, 0x4065, {                    \
+      0x86, 0xbc, 0x37, 0x46, 0xb5, 0xb3, 0x2c, 0xe8 \
+    }                                                \
+  }
+
+class nsNavHistoryContainerResultNode
+    : public nsNavHistoryResultNode,
+      public nsINavHistoryContainerResultNode {
+ public:
+  nsNavHistoryContainerResultNode(const nsACString& aURI,
+                                  const nsACString& aTitle, PRTime aTime,
+                                  uint32_t aContainerType,
+                                  nsNavHistoryQueryOptions* aOptions);
+
+  virtual nsresult Refresh();
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_NAVHISTORYCONTAINERRESULTNODE_IID)
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsNavHistoryContainerResultNode,
+                                           nsNavHistoryResultNode)
+  NS_FORWARD_COMMON_RESULTNODE_TO_BASE
+  NS_IMETHOD GetType(uint32_t* type) override {
+    *type = mContainerType;
+    return NS_OK;
+  }
+  NS_IMETHOD GetUri(nsACString& aURI) override {
+    aURI = mURI;
+    return NS_OK;
+  }
+  NS_DECL_NSINAVHISTORYCONTAINERRESULTNODE
+
+ public:
+  virtual void OnRemoving() override;
+
+  nsresult OnVisitsRemoved(nsIURI* aURI);
+
+  bool AreChildrenVisible();
+
+  // Overridded by descendents to populate.
+  virtual nsresult OpenContainer();
+  nsresult CloseContainer(bool aSuppressNotifications = false);
+
+  virtual nsresult OpenContainerAsync();
+
+  // This points to the result that owns this container. All containers have
+  // their result pointer set so we can quickly get to the result without having
+  // to walk the tree. Yet, this also saves us from storing a million pointers
+  // for every leaf node to the result.
+  RefPtr<nsNavHistoryResult> mResult;
+
+  // For example, RESULT_TYPE_QUERY. Query and Folder results override GetType
+  // so this is not used, but is still kept in sync.
+  uint32_t mContainerType;
+
+  // When there are children, this stores the open state in the tree
+  // this is set to the default in the constructor.
+  bool mExpanded;
+
+  // Filled in by the result type generator in nsNavHistory.
+  nsCOMArray<nsNavHistoryResultNode> mChildren;
+
+  // mOriginalOptions is the options object used to _define_ this specific
+  // container node. It may differ from mOptions, that is the options used
+  // to _fill_ this container node, because mOptions may be modified by
+  // the direct parent of this container node, see SetAsParentOfNode. For
+  // example, if the parent has excludeItems, options will have it too, even if
+  // originally this object was not defined with that option.
+  RefPtr<nsNavHistoryQueryOptions> mOriginalOptions;
+  RefPtr<nsNavHistoryQueryOptions> mOptions;
+
+  void FillStats();
+  // Sets this container as parent of aNode, propagating the appropriate
+  // options.
+  void SetAsParentOfNode(nsNavHistoryResultNode* aNode);
+  nsresult ReverseUpdateStats(int32_t aAccessCountChange);
+
+  // Sorting methods.
+  using SortComparator = nsCOMArray<nsNavHistoryResultNode>::TComparatorFunc;
+  virtual uint16_t GetSortType();
+
+  static SortComparator GetSortingComparator(uint16_t aSortType);
+  virtual void RecursiveSort(SortComparator aComparator);
+  int32_t FindInsertionPoint(nsNavHistoryResultNode* aNode,
+                             SortComparator aComparator, bool* aItemExists);
+  bool DoesChildNeedResorting(int32_t aIndex, SortComparator aComparator);
+
+  static int32_t SortComparison_StringLess(const nsAString& a,
+                                           const nsAString& b);
+
+  static int32_t SortComparison_Bookmark(nsNavHistoryResultNode* a,
+                                         nsNavHistoryResultNode* b);
+  static int32_t SortComparison_TitleLess(nsNavHistoryResultNode* a,
+                                          nsNavHistoryResultNode* b);
+  static int32_t SortComparison_TitleGreater(nsNavHistoryResultNode* a,
+                                             nsNavHistoryResultNode* b);
+  static int32_t SortComparison_DateLess(nsNavHistoryResultNode* a,
+                                         nsNavHistoryResultNode* b);
+  static int32_t SortComparison_DateGreater(nsNavHistoryResultNode* a,
+                                            nsNavHistoryResultNode* b);
+  static int32_t SortComparison_URILess(nsNavHistoryResultNode* a,
+                                        nsNavHistoryResultNode* b);
+  static int32_t SortComparison_URIGreater(nsNavHistoryResultNode* a,
+                                           nsNavHistoryResultNode* b);
+  static int32_t SortComparison_VisitCountLess(nsNavHistoryResultNode* a,
+                                               nsNavHistoryResultNode* b);
+  static int32_t SortComparison_VisitCountGreater(nsNavHistoryResultNode* a,
+                                                  nsNavHistoryResultNode* b);
+  static int32_t SortComparison_DateAddedLess(nsNavHistoryResultNode* a,
+                                              nsNavHistoryResultNode* b);
+  static int32_t SortComparison_DateAddedGreater(nsNavHistoryResultNode* a,
+                                                 nsNavHistoryResultNode* b);
+  static int32_t SortComparison_LastModifiedLess(nsNavHistoryResultNode* a,
+                                                 nsNavHistoryResultNode* b);
+  static int32_t SortComparison_LastModifiedGreater(nsNavHistoryResultNode* a,
+                                                    nsNavHistoryResultNode* b);
+  static int32_t SortComparison_TagsLess(nsNavHistoryResultNode* a,
+                                         nsNavHistoryResultNode* b);
+  static int32_t SortComparison_TagsGreater(nsNavHistoryResultNode* a,
+                                            nsNavHistoryResultNode* b);
+  static int32_t SortComparison_FrecencyLess(nsNavHistoryResultNode* a,
+                                             nsNavHistoryResultNode* b);
+  static int32_t SortComparison_FrecencyGreater(nsNavHistoryResultNode* a,
+                                                nsNavHistoryResultNode* b);
+
+  // finding children: THESE DO NOT ADDREF
+  nsNavHistoryResultNode* FindChildByURI(const nsACString& aSpec,
+                                         uint32_t* aNodeIndex);
+  void FindChildrenByURI(const nsCString& aSpec,
+                         nsCOMArray<nsNavHistoryResultNode>* aMatches);
+  // returns the index of the given node, -1 if not found
+  int32_t FindChild(nsNavHistoryResultNode* aNode) {
+    return mChildren.IndexOf(aNode);
+  }
+
+  nsNavHistoryResultNode* FindChildByGuid(const nsACString& guid,
+                                          int32_t* nodeIndex);
+
+  nsNavHistoryResultNode* FindChildById(int64_t aItemId, int32_t* aNodeIndex);
+
+  nsresult InsertChildAt(nsNavHistoryResultNode* aNode, int32_t aIndex);
+  nsresult InsertSortedChild(nsNavHistoryResultNode* aNode,
+                             bool aIgnoreDuplicates = false);
+  bool EnsureItemPosition(int32_t aIndex);
+
+  nsresult RemoveChildAt(int32_t aIndex);
+
+  void RecursiveFindURIs(bool aOnlyOne,
+                         nsNavHistoryContainerResultNode* aContainer,
+                         const nsCString& aSpec,
+                         nsCOMArray<nsNavHistoryResultNode>* aMatches);
+  bool UpdateURIs(bool aRecursive, bool aOnlyOne, bool aUpdateSort,
+                  const nsCString& aSpec,
+                  nsresult (*aCallback)(nsNavHistoryResultNode*, const void*,
+                                        const nsNavHistoryResult*),
+                  const void* aClosure);
+  nsresult ChangeTitles(nsIURI* aURI, const nsACString& aNewTitle,
+                        bool aRecursive, bool aOnlyOne);
+
+ protected:
+  virtual ~nsNavHistoryContainerResultNode();
+
+  enum AsyncCanceledState { NOT_CANCELED, CANCELED, CANCELED_RESTART_NEEDED };
+
+  void CancelAsyncOpen(bool aRestart);
+  nsresult NotifyOnStateChange(uint16_t aOldState);
+
+  nsCOMPtr<mozIStoragePendingStatement> mAsyncPendingStmt;
+  AsyncCanceledState mAsyncCanceledState;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsNavHistoryContainerResultNode,
+                              NS_NAVHISTORYCONTAINERRESULTNODE_IID)
+
+// nsNavHistoryQueryResultNode
+//
+//    Overridden container type for complex queries over history and/or
+//    bookmarks. This keeps itself in sync by listening to history and
+//    bookmark notifications.
+
+class nsNavHistoryQueryResultNode final
+    : public nsNavHistoryContainerResultNode,
+      public nsINavHistoryQueryResultNode {
+ public:
+  nsNavHistoryQueryResultNode(const nsACString& aTitle, PRTime aTime,
+                              const nsACString& aQueryURI,
+                              const RefPtr<nsNavHistoryQuery>& aQuery,
+                              const RefPtr<nsNavHistoryQueryOptions>& aOptions);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_FORWARD_COMMON_RESULTNODE_TO_BASE
+  NS_IMETHOD GetType(uint32_t* type) override {
+    *type = nsNavHistoryResultNode::RESULT_TYPE_QUERY;
+    return NS_OK;
+  }
+  NS_IMETHOD GetUri(nsACString& aURI) override;  // does special lazy creation
+  NS_FORWARD_CONTAINERNODE_EXCEPT_HASCHILDREN
+  NS_IMETHOD GetHasChildren(bool* aHasChildren) override;
+  NS_DECL_NSINAVHISTORYQUERYRESULTNODE
+
+  virtual nsresult OnMobilePrefChanged(bool newValue) override;
+
+  bool CanExpand();
+  bool IsContainersQuery();
+
+  virtual nsresult OpenContainer() override;
+
+  nsresult OnItemAdded(int64_t aItemId, int64_t aParentId, int32_t aIndex,
+                       uint16_t aItemType, nsIURI* aURI, PRTime aDateAdded,
+                       const nsACString& aGUID, const nsACString& aParentGUID,
+                       uint16_t aSource);
+  nsresult OnItemRemoved(int64_t aItemId, int64_t aParentFolder, int32_t aIndex,
+                         uint16_t aItemType, nsIURI* aURI,
+                         const nsACString& aGUID, const nsACString& aParentGUID,
+                         uint16_t aSource);
+  nsresult OnItemMoved(int64_t aFolder, int32_t aOldIndex, int32_t aNewIndex,
+                       uint16_t aItemType, const nsACString& aGUID,
+                       const nsACString& aOldParentGUID,
+                       const nsACString& aNewParentGUID, uint16_t aSource,
+                       const nsACString& aURI);
+  nsresult OnItemTagsChanged(int64_t aItemId, const nsAString& aURL,
+                             const nsAString& aTags);
+  nsresult OnItemTimeChanged(int64_t aItemId, const nsACString& aGUID,
+                             PRTime aDateAdded, PRTime aLastModified);
+  nsresult OnItemTitleChanged(int64_t aItemId, const nsACString& aGUID,
+                              const nsACString& aTitle, PRTime aLastModified);
+  nsresult OnItemUrlChanged(int64_t aItemId, const nsACString& aGUID,
+                            const nsACString& aURL, PRTime aLastModified);
+
+  // The internal version has an output aAdded parameter, it is incremented by
+  // query nodes when the visited uri belongs to them. If no such query exists,
+  // the history result creates a new query node dynamically.
+  nsresult OnVisit(nsIURI* aURI, int64_t aVisitId, PRTime aTime,
+                   uint32_t aTransitionType, const nsACString& aGUID,
+                   bool aHidden, uint32_t aVisitCount,
+                   const nsAString& aLastKnownTitle, int64_t aFrecency,
+                   uint32_t* aAdded);
+  nsresult OnTitleChanged(nsIURI* aURI, const nsAString& aPageTitle,
+                          const nsACString& aGUID);
+  nsresult OnClearHistory();
+  nsresult OnPageRemovedFromStore(nsIURI* aURI, const nsACString& aGUID,
+                                  uint16_t aReason);
+  nsresult OnPageRemovedVisits(nsIURI* aURI, bool aPartialRemoval,
+                               const nsACString& aGUID, uint16_t aReason,
+                               uint32_t aTransitionType);
+
+  virtual void OnRemoving() override;
+
+  nsresult OnBeginUpdateBatch();
+  nsresult OnEndUpdateBatch();
+
+ public:
+  RefPtr<nsNavHistoryQuery> mQuery;
+  bool mHasSearchTerms;
+  uint32_t mLiveUpdate;  // one of QUERYUPDATE_* in nsNavHistory.h
+
+  // safe options getter, ensures query is parsed
+  nsNavHistoryQueryOptions* Options();
+
+  // this indicates whether the query contents are valid, they don't go away
+  // after the container is closed until a notification comes in
+  bool mContentsValid;
+
+  nsresult FillChildren();
+  void ClearChildren(bool unregister);
+  nsresult Refresh() override;
+
+  virtual uint16_t GetSortType() override;
+  virtual void RecursiveSort(SortComparator aComparator) override;
+
+  uint32_t mBatchChanges;
+
+  // Tracks transition type filters.
+  nsTArray<uint32_t> mTransitions;
+
+ protected:
+  virtual ~nsNavHistoryQueryResultNode();
+};
+
+// nsNavHistoryFolderResultNode
+//
+//    Overridden container type for bookmark folders. It will keep the contents
+//    of the folder in sync with the bookmark service.
+
+class nsNavHistoryFolderResultNode final
+    : public nsNavHistoryContainerResultNode,
+      public nsINavHistoryQueryResultNode,
+      public mozilla::places::WeakAsyncStatementCallback {
+ public:
+  nsNavHistoryFolderResultNode(int64_t aItemId, const nsACString& aBookmarkGuid,
+                               int64_t aTargetFolderItemId,
+                               const nsACString& aTargetFolderGuid,
+                               const nsACString& aTitle,
+                               nsNavHistoryQueryOptions* aOptions);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_FORWARD_COMMON_RESULTNODE_TO_BASE
+  NS_IMETHOD GetType(uint32_t* type) override {
+    if (mTargetFolderItemId != mItemId) {
+      *type = nsNavHistoryResultNode::RESULT_TYPE_FOLDER_SHORTCUT;
+    } else {
+      *type = nsNavHistoryResultNode::RESULT_TYPE_FOLDER;
+    }
+    return NS_OK;
+  }
+  NS_IMETHOD GetUri(nsACString& aURI) override;
+  NS_FORWARD_CONTAINERNODE_EXCEPT_HASCHILDREN
+  NS_IMETHOD GetHasChildren(bool* aHasChildren) override;
+  NS_DECL_NSINAVHISTORYQUERYRESULTNODE
+
+  virtual nsresult OpenContainer() override;
+
+  virtual nsresult OpenContainerAsync() override;
+  NS_DECL_ASYNCSTATEMENTCALLBACK
+
+  nsresult OnItemAdded(int64_t aItemId, int64_t aParentFolder, int32_t aIndex,
+                       uint16_t aItemType, nsIURI* aURI, PRTime aDateAdded,
+                       const nsACString& aGUID, const nsACString& aParentGUID,
+                       uint16_t aSource, const nsACString& aTitle,
+                       const nsAString& aTags, int64_t aFrecency, bool aHidden,
+                       uint32_t aVisitCount, PRTime aLastVisitDate,
+                       int64_t aTargetFolderItemId,
+                       const nsACString& aTargetFolderGuid,
+                       const nsACString& aTargetFolderTitle);
+  nsresult OnItemRemoved(int64_t aItemId, int64_t aParentFolder, int32_t aIndex,
+                         uint16_t aItemType, nsIURI* aURI,
+                         const nsACString& aGUID, const nsACString& aParentGUID,
+                         uint16_t aSource);
+  nsresult OnItemMoved(int64_t aItemId, int32_t aOldIndex, int32_t aNewIndex,
+                       uint16_t aItemType, const nsACString& aGUID,
+                       const nsACString& aOldParentGUID,
+                       const nsACString& aNewParentGUID, uint16_t aSource,
+                       const nsACString& aURI, const nsACString& aTitle,
+                       const nsAString& aTags, int64_t aFrecency, bool aHidden,
+                       uint32_t aVisitCount, PRTime aLastVisitDate,
+                       PRTime aDateAdded);
+  nsresult OnItemVisited(nsIURI* aURI, int64_t aVisitId, PRTime aTime,
+                         int64_t aFrecency);
+
+  virtual void OnRemoving() override;
+
+  // this indicates whether the folder contents are valid, they don't go away
+  // after the container is closed until a notification comes in
+  bool mContentsValid;
+
+  // If the node is generated from a place:folder=X query, this is the target
+  // folder id and GUID.  For regular folder nodes, they are set to the same
+  // values as mItemId and mBookmarkGuid. For more complex queries, they are set
+  // to -1/an empty string.
+  int64_t mTargetFolderItemId;
+  nsCString mTargetFolderGuid;
+
+  nsresult FillChildren();
+  void ClearChildren(bool aUnregister);
+  nsresult Refresh() override;
+
+  bool StartIncrementalUpdate();
+  void ReindexRange(int32_t aStartIndex, int32_t aEndIndex, int32_t aDelta);
+
+  nsresult OnBeginUpdateBatch();
+  nsresult OnEndUpdateBatch();
+
+ protected:
+  virtual ~nsNavHistoryFolderResultNode();
+
+ private:
+  nsresult OnChildrenFilled();
+  void EnsureRegisteredAsFolderObserver();
+  nsresult FillChildrenAsync();
+
+  bool mIsRegisteredFolderObserver;
+  int32_t mAsyncBookmarkIndex;
+};
+
+// nsNavHistorySeparatorResultNode
+//
+// Separator result nodes do not hold any data.
+class nsNavHistorySeparatorResultNode : public nsNavHistoryResultNode {
+ public:
+  nsNavHistorySeparatorResultNode();
+
+  NS_IMETHOD GetType(uint32_t* type) override {
+    *type = nsNavHistoryResultNode::RESULT_TYPE_SEPARATOR;
+    return NS_OK;
+  }
+};
+
+#endif  // nsNavHistoryResult_h_
diff --git a/toolkit/components/places/nsPlacesIndexes.h b/toolkit/components/places/nsPlacesIndexes.h
new file mode 100644
index 0000000000..c073691c19
--- /dev/null
+++ b/toolkit/components/places/nsPlacesIndexes.h
@@ -0,0 +1,118 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPlacesIndexes_h__
+#define nsPlacesIndexes_h__
+
+#define CREATE_PLACES_IDX(__name, __table, __columns, __type)                  \
+  nsLiteralCString("CREATE " __type " INDEX IF NOT EXISTS " __table "_" __name \
+                   " ON " __table " (" __columns ")")
+
+/**
+ * moz_places
+ */
+#define CREATE_IDX_MOZ_PLACES_URL_HASH \
+  CREATE_PLACES_IDX("url_hashindex", "moz_places", "url_hash", "")
+
+#define CREATE_IDX_MOZ_PLACES_REVHOST \
+  CREATE_PLACES_IDX("hostindex", "moz_places", "rev_host", "")
+
+#define CREATE_IDX_MOZ_PLACES_VISITCOUNT \
+  CREATE_PLACES_IDX("visitcount", "moz_places", "visit_count", "")
+
+#define CREATE_IDX_MOZ_PLACES_FRECENCY \
+  CREATE_PLACES_IDX("frecencyindex", "moz_places", "frecency", "")
+
+#define CREATE_IDX_MOZ_PLACES_LASTVISITDATE \
+  CREATE_PLACES_IDX("lastvisitdateindex", "moz_places", "last_visit_date", "")
+
+#define CREATE_IDX_MOZ_PLACES_GUID \
+  CREATE_PLACES_IDX("guid_uniqueindex", "moz_places", "guid", "UNIQUE")
+
+#define CREATE_IDX_MOZ_PLACES_ORIGIN_ID \
+  CREATE_PLACES_IDX("originidindex", "moz_places", "origin_id", "")
+
+#define CREATE_IDX_MOZ_PLACES_ALT_FRECENCY \
+  CREATE_PLACES_IDX("altfrecencyindex", "moz_places", "alt_frecency", "")
+
+/**
+ * moz_historyvisits
+ */
+
+#define CREATE_IDX_MOZ_HISTORYVISITS_PLACEDATE             \
+  CREATE_PLACES_IDX("placedateindex", "moz_historyvisits", \
+                    "place_id, visit_date", "")
+
+#define CREATE_IDX_MOZ_HISTORYVISITS_FROMVISIT \
+  CREATE_PLACES_IDX("fromindex", "moz_historyvisits", "from_visit", "")
+
+#define CREATE_IDX_MOZ_HISTORYVISITS_VISITDATE \
+  CREATE_PLACES_IDX("dateindex", "moz_historyvisits", "visit_date", "")
+
+/**
+ * moz_bookmarks
+ */
+
+#define CREATE_IDX_MOZ_BOOKMARKS_PLACETYPE \
+  CREATE_PLACES_IDX("itemindex", "moz_bookmarks", "fk, type", "")
+
+#define CREATE_IDX_MOZ_BOOKMARKS_PARENTPOSITION \
+  CREATE_PLACES_IDX("parentindex", "moz_bookmarks", "parent, position", "")
+
+#define CREATE_IDX_MOZ_BOOKMARKS_PLACELASTMODIFIED            \
+  CREATE_PLACES_IDX("itemlastmodifiedindex", "moz_bookmarks", \
+                    "fk, lastModified", "")
+
+#define CREATE_IDX_MOZ_BOOKMARKS_DATEADDED \
+  CREATE_PLACES_IDX("dateaddedindex", "moz_bookmarks", "dateAdded", "")
+
+#define CREATE_IDX_MOZ_BOOKMARKS_GUID \
+  CREATE_PLACES_IDX("guid_uniqueindex", "moz_bookmarks", "guid", "UNIQUE")
+
+/**
+ * moz_annos
+ */
+
+#define CREATE_IDX_MOZ_ANNOS_PLACEATTRIBUTE             \
+  CREATE_PLACES_IDX("placeattributeindex", "moz_annos", \
+                    "place_id, anno_attribute_id", "UNIQUE")
+
+/**
+ * moz_items_annos
+ */
+
+#define CREATE_IDX_MOZ_ITEMSANNOS_PLACEATTRIBUTE             \
+  CREATE_PLACES_IDX("itemattributeindex", "moz_items_annos", \
+                    "item_id, anno_attribute_id", "UNIQUE")
+
+/**
+ * moz_keywords
+ */
+
+#define CREATE_IDX_MOZ_KEYWORDS_PLACEPOSTDATA                    \
+  CREATE_PLACES_IDX("placepostdata_uniqueindex", "moz_keywords", \
+                    "place_id, post_data", "UNIQUE")
+
+// moz_pages_w_icons
+
+#define CREATE_IDX_MOZ_PAGES_W_ICONS_ICONURLHASH \
+  CREATE_PLACES_IDX("urlhashindex", "moz_pages_w_icons", "page_url_hash", "")
+
+// moz_icons
+
+#define CREATE_IDX_MOZ_ICONS_ICONURLHASH \
+  CREATE_PLACES_IDX("iconurlhashindex", "moz_icons", "fixed_icon_url_hash", "")
+
+// moz_places_metadata
+#define CREATE_IDX_MOZ_PLACES_METADATA_PLACECREATED                    \
+  CREATE_PLACES_IDX("placecreated_uniqueindex", "moz_places_metadata", \
+                    "place_id, created_at", "UNIQUE")
+
+#define CREATE_IDX_MOZ_PLACES_METADATA_REFERRER             \
+  CREATE_PLACES_IDX("referrerindex", "moz_places_metadata", \
+                    "referrer_place_id", "")
+
+#endif  // nsPlacesIndexes_h__
diff --git a/toolkit/components/places/nsPlacesMacros.h b/toolkit/components/places/nsPlacesMacros.h
new file mode 100644
index 0000000000..9d192eddb6
--- /dev/null
+++ b/toolkit/components/places/nsPlacesMacros.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#define PLACES_FACTORY_SINGLETON_IMPLEMENTATION(_className, _sInstance)     \
+  _className* _className::_sInstance = nullptr;                             \
+                                                                            \
+  already_AddRefed<_className> _className::GetSingleton() {                 \
+    if (_sInstance) {                                                       \
+      RefPtr<_className> ret = _sInstance;                                  \
+      return ret.forget();                                                  \
+    }                                                                       \
+    _sInstance = new _className();                                          \
+    RefPtr<_className> ret = _sInstance;                                    \
+    if (NS_FAILED(_sInstance->Init())) {                                    \
+      /* Null out ret before _sInstance so the destructor doesn't assert */ \
+      ret = nullptr;                                                        \
+      _sInstance = nullptr;                                                 \
+      return nullptr;                                                       \
+    }                                                                       \
+    return ret.forget();                                                    \
+  }
diff --git a/toolkit/components/places/nsPlacesTables.h b/toolkit/components/places/nsPlacesTables.h
new file mode 100644
index 0000000000..fcccee4aa3
--- /dev/null
+++ b/toolkit/components/places/nsPlacesTables.h
@@ -0,0 +1,311 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsPlacesTables_h__
+#define __nsPlacesTables_h__
+
+#define CREATE_MOZ_PLACES                                \
+  nsLiteralCString(                                      \
+      "CREATE TABLE moz_places ( "                       \
+      "  id INTEGER PRIMARY KEY"                         \
+      ", url LONGVARCHAR"                                \
+      ", title LONGVARCHAR"                              \
+      ", rev_host LONGVARCHAR"                           \
+      ", visit_count INTEGER DEFAULT 0"                  \
+      ", hidden INTEGER DEFAULT 0 NOT NULL"              \
+      ", typed INTEGER DEFAULT 0 NOT NULL"               \
+      ", frecency INTEGER DEFAULT -1 NOT NULL"           \
+      ", last_visit_date INTEGER "                       \
+      ", guid TEXT"                                      \
+      ", foreign_count INTEGER DEFAULT 0 NOT NULL"       \
+      ", url_hash INTEGER DEFAULT 0 NOT NULL "           \
+      ", description TEXT"                               \
+      ", preview_image_url TEXT"                         \
+      ", site_name TEXT"                                 \
+      ", origin_id INTEGER REFERENCES moz_origins(id)"   \
+      ", recalc_frecency INTEGER NOT NULL DEFAULT 0"     \
+      ", alt_frecency INTEGER"                           \
+      ", recalc_alt_frecency INTEGER NOT NULL DEFAULT 0" \
+      ")")
+
+#define CREATE_MOZ_HISTORYVISITS            \
+  nsLiteralCString(                         \
+      "CREATE TABLE moz_historyvisits ("    \
+      "  id INTEGER PRIMARY KEY"            \
+      ", from_visit INTEGER"                \
+      ", place_id INTEGER"                  \
+      ", visit_date INTEGER"                \
+      ", visit_type INTEGER"                \
+      ", session INTEGER"                   \
+      ", source INTEGER DEFAULT 0 NOT NULL" \
+      ", triggeringPlaceId INTEGER"         \
+      ")")
+
+// These two tables were designed to store data with json in mind
+// ideally one column per "consumer" (sync, annotations, etc) to keep
+// concerns separate. Using an UPSERT is the suggested way to update
+// this table vs INSERT OR REPLACE to avoid clearing out any existing properties
+// see PlacesSyncUtils.sys.mjs for an example of how sync does this
+#define CREATE_MOZ_PLACES_EXTRA                                               \
+  nsLiteralCString(                                                           \
+      "CREATE TABLE moz_places_extra ("                                       \
+      "  place_id INTEGER PRIMARY KEY NOT NULL"                               \
+      ", sync_json TEXT"                                                      \
+      ", FOREIGN KEY (place_id) REFERENCES moz_places(id) ON DELETE CASCADE " \
+      ")")
+
+#define CREATE_MOZ_HISTORYVISITS_EXTRA                                \
+  nsLiteralCString(                                                   \
+      "CREATE TABLE moz_historyvisits_extra ("                        \
+      "  visit_id INTEGER PRIMARY KEY NOT NULL"                       \
+      ", sync_json TEXT"                                              \
+      ", FOREIGN KEY (visit_id) REFERENCES moz_historyvisits(id) ON " \
+      "  DELETE CASCADE"                                              \
+      ")")
+
+#define CREATE_MOZ_INPUTHISTORY         \
+  nsLiteralCString(                     \
+      "CREATE TABLE moz_inputhistory (" \
+      "  place_id INTEGER NOT NULL"     \
+      ", input LONGVARCHAR NOT NULL"    \
+      ", use_count INTEGER"             \
+      ", PRIMARY KEY (place_id, input)" \
+      ")")
+
+// Note: flags, expiration, type, dateAdded and lastModified should be
+// considered deprecated but are kept to ease backwards compatibility.
+#define CREATE_MOZ_ANNOS                 \
+  nsLiteralCString(                      \
+      "CREATE TABLE moz_annos ("         \
+      "  id INTEGER PRIMARY KEY"         \
+      ", place_id INTEGER NOT NULL"      \
+      ", anno_attribute_id INTEGER"      \
+      ", content LONGVARCHAR"            \
+      ", flags INTEGER DEFAULT 0"        \
+      ", expiration INTEGER DEFAULT 0"   \
+      ", type INTEGER DEFAULT 0"         \
+      ", dateAdded INTEGER DEFAULT 0"    \
+      ", lastModified INTEGER DEFAULT 0" \
+      ")")
+
+#define CREATE_MOZ_ANNO_ATTRIBUTES         \
+  nsLiteralCString(                        \
+      "CREATE TABLE moz_anno_attributes (" \
+      "  id INTEGER PRIMARY KEY"           \
+      ", name VARCHAR(32) UNIQUE NOT NULL" \
+      ")")
+
+#define CREATE_MOZ_ITEMS_ANNOS           \
+  nsLiteralCString(                      \
+      "CREATE TABLE moz_items_annos ("   \
+      "  id INTEGER PRIMARY KEY"         \
+      ", item_id INTEGER NOT NULL"       \
+      ", anno_attribute_id INTEGER"      \
+      ", content LONGVARCHAR"            \
+      ", flags INTEGER DEFAULT 0"        \
+      ", expiration INTEGER DEFAULT 0"   \
+      ", type INTEGER DEFAULT 0"         \
+      ", dateAdded INTEGER DEFAULT 0"    \
+      ", lastModified INTEGER DEFAULT 0" \
+      ")")
+
+#define CREATE_MOZ_BOOKMARKS                                                   \
+  nsLiteralCString(                                                            \
+      "CREATE TABLE moz_bookmarks ("                                           \
+      "  id INTEGER PRIMARY KEY"                                               \
+      ", type INTEGER"                                                         \
+      ", fk INTEGER DEFAULT NULL" /* place_id */                               \
+      ", parent INTEGER"                                                       \
+      ", position INTEGER"                                                     \
+      ", title LONGVARCHAR"                                                    \
+      ", keyword_id INTEGER"                                                   \
+      ", folder_type TEXT"                                                     \
+      ", dateAdded INTEGER"                                                    \
+      ", lastModified INTEGER"                                                 \
+      ", guid TEXT" /* The sync status is determined from the change source.   \
+                       We set this to SYNC_STATUS_NEW = 1 for new local        \
+                       bookmarks, and SYNC_STATUS_NORMAL = 2 for bookmarks     \
+                       from other devices. Uploading a local bookmark for the  \
+                       first time changes its status to SYNC_STATUS_NORMAL.    \
+                       For bookmarks restored from a backup, we set            \
+                       SYNC_STATUS_UNKNOWN = 0, indicating that Sync should    \
+                       reconcile them with bookmarks on the server. If Sync is \
+                       disconnected or never set up, all bookmarks will stay   \
+                       in SYNC_STATUS_NEW.                                     \
+                    */                                                         \
+      ", syncStatus INTEGER NOT NULL DEFAULT 0" /* This field is incremented   \
+                                                   for every bookmark change   \
+                                                   that should trigger a sync. \
+                                                   It's a counter instead of a \
+                                                   Boolean so that we can      \
+                                                   track changes made during a \
+                                                   sync, and queue them for    \
+                                                   the next sync. Changes made \
+                                                   by Sync don't bump the      \
+                                                   counter, to avoid sync      \
+                                                   loops. If Sync is           \
+                                                   disconnected, we'll reset   \
+                                                   the counter to 1 for all    \
+                                                   bookmarks.                  \
+                                                */                             \
+      ", syncChangeCounter INTEGER NOT NULL DEFAULT 1"                         \
+      ")")
+
+// This table stores tombstones for bookmarks with SYNC_STATUS_NORMAL. We
+// upload tombstones during a sync, and delete them from this table on success.
+// If Sync is disconnected, we'll delete all stored tombstones. If Sync is
+// never set up, we'll never write new tombstones, since all bookmarks will stay
+// in SYNC_STATUS_NEW.
+#define CREATE_MOZ_BOOKMARKS_DELETED             \
+  nsLiteralCString(                              \
+      "CREATE TABLE moz_bookmarks_deleted ("     \
+      "  guid TEXT PRIMARY KEY"                  \
+      ", dateRemoved INTEGER NOT NULL DEFAULT 0" \
+      ")")
+
+#define CREATE_MOZ_KEYWORDS                    \
+  nsLiteralCString(                            \
+      "CREATE TABLE moz_keywords ("            \
+      "  id INTEGER PRIMARY KEY AUTOINCREMENT" \
+      ", keyword TEXT UNIQUE"                  \
+      ", place_id INTEGER"                     \
+      ", post_data TEXT"                       \
+      ")")
+
+#define CREATE_MOZ_ORIGINS                               \
+  nsLiteralCString(                                      \
+      "CREATE TABLE moz_origins ( "                      \
+      "id INTEGER PRIMARY KEY, "                         \
+      "prefix TEXT NOT NULL, "                           \
+      "host TEXT NOT NULL, "                             \
+      "frecency INTEGER NOT NULL, "                      \
+      "recalc_frecency INTEGER NOT NULL DEFAULT 0, "     \
+      "alt_frecency INTEGER, "                           \
+      "recalc_alt_frecency INTEGER NOT NULL DEFAULT 0, " \
+      "UNIQUE (prefix, host) "                           \
+      ")")
+
+// Note: this should be kept up-to-date with the definition in
+//       nsPlacesAutoComplete.js.
+#define CREATE_MOZ_OPENPAGES_TEMP              \
+  nsLiteralCString(                            \
+      "CREATE TEMP TABLE moz_openpages_temp (" \
+      "  url TEXT"                             \
+      ", userContextId INTEGER"                \
+      ", open_count INTEGER"                   \
+      ", PRIMARY KEY (url, userContextId)"     \
+      ")")
+
+// This table is used to remove orphan origins after pages are removed from
+// moz_places. Insertions are made by moz_places_afterdelete_trigger.
+// This allows for more performant handling of batch removals, since we'll look
+// for orphan origins only once, instead of doing it for each page removal.
+// The downside of this approach is that after the removal is complete the
+// consumer must remember to also delete from this table, and a trigger will
+// take care of orphans.
+#define CREATE_UPDATEORIGINSDELETE_TEMP                   \
+  nsLiteralCString(                                       \
+      "CREATE TEMP TABLE moz_updateoriginsdelete_temp ( " \
+      "  prefix TEXT NOT NULL, "                          \
+      "  host TEXT NOT NULL, "                            \
+      "  PRIMARY KEY (prefix, host) "                     \
+      ") WITHOUT ROWID")
+
+// This table would not be strictly needed for functionality since it's just
+// mimicking moz_places, though it's great for database portability.
+// With this we don't have to take care into account a bunch of database
+// mismatch cases, where places.sqlite could be mixed up with a favicons.sqlite
+// created with a different places.sqlite (not just in case of a user messing
+// up with the profile, but also in case of corruption).
+#define CREATE_MOZ_PAGES_W_ICONS          \
+  nsLiteralCString(                       \
+      "CREATE TABLE moz_pages_w_icons ( " \
+      "id INTEGER PRIMARY KEY, "          \
+      "page_url TEXT NOT NULL, "          \
+      "page_url_hash INTEGER NOT NULL "   \
+      ") ")
+
+// This table retains the icons data. The hashes url is "fixed" (thus the scheme
+// and www are trimmed in most cases) so we can quickly query for root icon urls
+// like "domain/favicon.ico".
+// We are considering squared icons for simplicity, so storing only one size.
+// For svg payloads, width will be set to 65535 (UINT16_MAX).
+#define CREATE_MOZ_ICONS                       \
+  nsLiteralCString(                            \
+      "CREATE TABLE moz_icons ( "              \
+      "id INTEGER PRIMARY KEY, "               \
+      "icon_url TEXT NOT NULL, "               \
+      "fixed_icon_url_hash INTEGER NOT NULL, " \
+      "width INTEGER NOT NULL DEFAULT 0, "     \
+      "root INTEGER NOT NULL DEFAULT 0, "      \
+      "color INTEGER, "                        \
+      "expire_ms INTEGER NOT NULL DEFAULT 0, " \
+      "data BLOB "                             \
+      ") ")
+
+// This table maintains relations between icons and pages.
+// Each page can have multiple icons, and each icon can be used by multiple
+// pages.
+#define CREATE_MOZ_ICONS_TO_PAGES                                              \
+  nsLiteralCString(                                                            \
+      "CREATE TABLE moz_icons_to_pages ( "                                     \
+      "page_id INTEGER NOT NULL, "                                             \
+      "icon_id INTEGER NOT NULL, "                                             \
+      "expire_ms INTEGER NOT NULL DEFAULT 0, "                                 \
+      "PRIMARY KEY (page_id, icon_id), "                                       \
+      "FOREIGN KEY (page_id) REFERENCES moz_pages_w_icons ON DELETE CASCADE, " \
+      "FOREIGN KEY (icon_id) REFERENCES moz_icons ON DELETE CASCADE "          \
+      ") WITHOUT ROWID ")
+
+// This table holds key-value metadata for Places and its consumers. Sync stores
+// the sync IDs for the bookmarks and history collections in this table, and the
+// last sync time for history.
+#define CREATE_MOZ_META         \
+  nsLiteralCString(             \
+      "CREATE TABLE moz_meta (" \
+      "key TEXT PRIMARY KEY, "  \
+      "value NOT NULL"          \
+      ") WITHOUT ROWID ")
+
+// This table holds history interactions that will be used to achieve improved
+// history recalls.
+#define CREATE_MOZ_PLACES_METADATA                                           \
+  nsLiteralCString(                                                          \
+      "CREATE TABLE moz_places_metadata ("                                   \
+      "id INTEGER PRIMARY KEY, "                                             \
+      "place_id INTEGER NOT NULL, "                                          \
+      "referrer_place_id INTEGER, "                                          \
+      "created_at INTEGER NOT NULL DEFAULT 0, "                              \
+      "updated_at INTEGER NOT NULL DEFAULT 0, "                              \
+      "total_view_time INTEGER NOT NULL DEFAULT 0, "                         \
+      "typing_time INTEGER NOT NULL DEFAULT 0, "                             \
+      "key_presses INTEGER NOT NULL DEFAULT 0, "                             \
+      "scrolling_time INTEGER NOT NULL DEFAULT 0, "                          \
+      "scrolling_distance INTEGER NOT NULL DEFAULT 0, "                      \
+      "document_type INTEGER NOT NULL DEFAULT 0, "                           \
+      "search_query_id INTEGER, "                                            \
+      "FOREIGN KEY (place_id) REFERENCES moz_places(id) ON DELETE CASCADE, " \
+      "FOREIGN KEY (referrer_place_id) REFERENCES moz_places(id) ON DELETE " \
+      "CASCADE, "                                                            \
+      "FOREIGN KEY(search_query_id) REFERENCES "                             \
+      "moz_places_metadata_search_queries(id) ON DELETE CASCADE "            \
+      "CHECK(place_id != referrer_place_id) "                                \
+      ")")
+
+#define CREATE_MOZ_PLACES_METADATA_SEARCH_QUERIES                        \
+  nsLiteralCString(                                                      \
+      "CREATE TABLE IF NOT EXISTS moz_places_metadata_search_queries ( " \
+      "id INTEGER PRIMARY KEY, "                                         \
+      "terms TEXT NOT NULL UNIQUE "                                      \
+      ")")
+
+#define CREATE_MOZ_PREVIEWS_TOMBSTONES                        \
+  nsLiteralCString(                                           \
+      "CREATE TABLE IF NOT EXISTS moz_previews_tombstones ( " \
+      "  hash TEXT PRIMARY KEY "                              \
+      ") WITHOUT ROWID")
+
+#endif  // __nsPlacesTables_h__
diff --git a/toolkit/components/places/nsPlacesTriggers.h b/toolkit/components/places/nsPlacesTriggers.h
new file mode 100644
index 0000000000..0281054c16
--- /dev/null
+++ b/toolkit/components/places/nsPlacesTriggers.h
@@ -0,0 +1,365 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPlacesTables.h"
+
+#ifndef __nsPlacesTriggers_h__
+#  define __nsPlacesTriggers_h__
+
+/**
+ * These visit types are excluded from visit_count:
+ *  0 - invalid
+ *  4 - EMBED
+ *  7 - DOWNLOAD
+ *  8 - FRAMED_LINK
+ *  9 - RELOAD
+ **/
+#  define VISIT_COUNT_INC(field) \
+    "(CASE WHEN " field " IN (0, 4, 7, 8, 9) THEN 0 ELSE 1 END) "
+
+/**
+ * This triggers update visit_count and last_visit_date based on historyvisits
+ * table changes.
+ */
+#  define CREATE_HISTORYVISITS_AFTERINSERT_TRIGGER \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_historyvisits_afterinsert_v2_trigger "       \
+        "AFTER INSERT ON moz_historyvisits FOR EACH ROW "                     \
+        "BEGIN "                                                              \
+        "SELECT invalidate_days_of_history();"                                \
+        "SELECT store_last_inserted_id('moz_historyvisits', NEW.id); "        \
+        "UPDATE moz_places SET "                                              \
+        "visit_count = visit_count + " VISIT_COUNT_INC("NEW.visit_type") ", " \
+        "recalc_frecency = 1, "                                               \
+        "recalc_alt_frecency = 1, "                                           \
+        "last_visit_date = MAX(IFNULL(last_visit_date, 0), NEW.visit_date) "  \
+        "WHERE id = NEW.place_id;"                                            \
+        "END")
+
+#  define CREATE_HISTORYVISITS_AFTERDELETE_TRIGGER \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_historyvisits_afterdelete_v2_trigger "       \
+        "AFTER DELETE ON moz_historyvisits FOR EACH ROW "                     \
+        "BEGIN "                                                              \
+        "SELECT invalidate_days_of_history();"                                \
+        "UPDATE moz_places SET "                                              \
+        "visit_count = visit_count - " VISIT_COUNT_INC("OLD.visit_type") ", " \
+        "recalc_frecency = (frecency <> 0), "                                 \
+        "recalc_alt_frecency = (frecency <> 0), "                             \
+        "last_visit_date = (SELECT visit_date FROM moz_historyvisits "        \
+        "WHERE place_id = OLD.place_id "                                      \
+        "ORDER BY visit_date DESC LIMIT 1) "                                  \
+        "WHERE id = OLD.place_id;"                                            \
+        "END")
+
+// This trigger stores the last_inserted_id, and inserts entries in moz_origins
+// when pages are added.
+#  define CREATE_PLACES_AFTERINSERT_TRIGGER                                 \
+    nsLiteralCString(                                                       \
+        "CREATE TEMP TRIGGER moz_places_afterinsert_trigger "               \
+        "AFTER INSERT ON moz_places FOR EACH ROW "                          \
+        "BEGIN "                                                            \
+        "SELECT store_last_inserted_id('moz_places', NEW.id); "             \
+        "INSERT INTO moz_origins "                                          \
+        "  (prefix, host, frecency, recalc_frecency, recalc_alt_frecency) " \
+        "VALUES (get_prefix(NEW.url), get_host_and_port(NEW.url), "         \
+        "        NEW.frecency, 1, 1)  "                                     \
+        "ON CONFLICT(prefix, host) DO UPDATE "                              \
+        "  SET recalc_frecency = 1, recalc_alt_frecency = 1 "               \
+        "  WHERE EXCLUDED.recalc_frecency = 0 OR "                          \
+        "        EXCLUDED.recalc_alt_frecency = 0; "                        \
+        "UPDATE moz_places SET origin_id = ( "                              \
+        "  SELECT id "                                                      \
+        "  FROM moz_origins "                                               \
+        "  WHERE prefix = get_prefix(NEW.url) "                             \
+        "    AND host = get_host_and_port(NEW.url) "                        \
+        ") "                                                                \
+        "WHERE id = NEW.id; "                                               \
+        "END")
+
+// This trigger is a workaround for the lack of FOR EACH STATEMENT in Sqlite.
+// While doing deletes into moz_places, we accumulate the affected origins into
+// a temp table. Afterwards, we delete everything from the temp table, causing
+// the AFTER DELETE trigger to fire for it, which will then update moz_origins.
+//
+// Note this way we lose atomicity, crashing between the 2 queries may break the
+// tables' coherency. So it's better to run those DELETE queries in the same
+// transaction as the original change.
+#  define CREATE_PLACES_AFTERDELETE_TRIGGER                                    \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_places_afterdelete_trigger "                  \
+        "AFTER DELETE ON moz_places FOR EACH ROW "                             \
+        "BEGIN "                                                               \
+        "INSERT OR IGNORE INTO moz_updateoriginsdelete_temp (prefix, host) "   \
+        "VALUES (get_prefix(OLD.url), get_host_and_port(OLD.url)); "           \
+        "UPDATE moz_origins SET recalc_frecency = 1, recalc_alt_frecency = 1 " \
+        "WHERE id = OLD.origin_id; "                                           \
+        "END ")
+
+// This is an alternate version of CREATE_PLACES_AFTERDELETE_TRIGGER, with
+// support for previews tombstones. Only one of these should be used at the
+// same time
+#  define CREATE_PLACES_AFTERDELETE_WPREVIEWS_TRIGGER                          \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_places_afterdelete_wpreviews_trigger "        \
+        "AFTER DELETE ON moz_places FOR EACH ROW "                             \
+        "BEGIN "                                                               \
+        "INSERT OR IGNORE INTO moz_updateoriginsdelete_temp (prefix, host) "   \
+        "VALUES (get_prefix(OLD.url), get_host_and_port(OLD.url)); "           \
+        "UPDATE moz_origins SET recalc_frecency = 1, recalc_alt_frecency = 1 " \
+        "WHERE id = OLD.origin_id; "                                           \
+        "INSERT OR IGNORE INTO moz_previews_tombstones VALUES "                \
+        "(md5hex(OLD.url));"                                                   \
+        "END ")
+
+// This is the supporting table for the "AFTER DELETE ON moz_places" triggers.
+#  define CREATE_UPDATEORIGINSDELETE_AFTERDELETE_TRIGGER                   \
+    nsLiteralCString(                                                      \
+        "CREATE TEMP TRIGGER moz_updateoriginsdelete_afterdelete_trigger " \
+        "AFTER DELETE ON moz_updateoriginsdelete_temp FOR EACH ROW "       \
+        "BEGIN "                                                           \
+        "DELETE FROM moz_origins "                                         \
+        "WHERE prefix = OLD.prefix AND host = OLD.host "                   \
+        "AND NOT EXISTS ( "                                                \
+        "    SELECT id FROM moz_places "                                   \
+        "    WHERE origin_id = moz_origins.id "                            \
+        "); "                                                              \
+        "END")
+
+// This trigger runs on updates to moz_places.frecency.
+//
+// However, we skip this when frecency changes are due to frecency decay
+// since (1) decay updates all frecencies at once, so this trigger would
+// run for each moz_place, which would be expensive; and (2) decay does
+// not change the ordering of frecencies since all frecencies decay by
+// the same percentage.
+#  define CREATE_PLACES_AFTERUPDATE_FRECENCY_TRIGGER                           \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_places_afterupdate_frecency_trigger "         \
+        "AFTER UPDATE OF frecency ON moz_places FOR EACH ROW "                 \
+        "WHEN NOT is_frecency_decaying() "                                     \
+        "BEGIN "                                                               \
+        "UPDATE moz_places SET recalc_frecency = 0 WHERE id = NEW.id; "        \
+        "UPDATE moz_origins SET recalc_frecency = 1, recalc_alt_frecency = 1 " \
+        "WHERE id = NEW.origin_id; "                                           \
+        "END ")
+
+// Runs when recalc_frecency is set to 1
+#  define CREATE_PLACES_AFTERUPDATE_RECALC_FRECENCY_TRIGGER                   \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_places_afterupdate_recalc_frecency_trigger " \
+        "AFTER UPDATE OF recalc_frecency ON moz_places FOR EACH ROW "         \
+        "WHEN NEW.recalc_frecency = 1 "                                       \
+        "BEGIN "                                                              \
+        "  SELECT set_should_start_frecency_recalculation();"                 \
+        "END")
+#  define CREATE_ORIGINS_AFTERUPDATE_RECALC_FRECENCY_TRIGGER                   \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_origins_afterupdate_recalc_frecency_trigger " \
+        "AFTER UPDATE OF recalc_frecency ON moz_origins FOR EACH ROW "         \
+        "WHEN NEW.recalc_frecency = 1 "                                        \
+        "BEGIN "                                                               \
+        "  SELECT set_should_start_frecency_recalculation();"                  \
+        "END")
+
+// Runs when origin frecency is set to 0.
+// This is in addition to moz_updateoriginsdelete_afterdelete_trigger, as a
+// sanity check to ensure orphan origins don't stay around. We cannot just rely
+// on this because it runs delayed and in the meanwhile the existence of the
+// origin may impact user's privacy.
+#  define CREATE_ORIGINS_AFTERUPDATE_FRECENCY_TRIGGER                   \
+    nsLiteralCString(                                                   \
+        "CREATE TEMP TRIGGER moz_origins_afterupdate_frecency_trigger " \
+        "AFTER UPDATE OF recalc_frecency ON moz_origins FOR EACH ROW "  \
+        "WHEN NEW.frecency = 0 AND OLD.frecency > 0 "                   \
+        "BEGIN "                                                        \
+        "DELETE FROM moz_origins "                                      \
+        "WHERE id = NEW.id AND NOT EXISTS ( "                           \
+        "  SELECT id FROM moz_places WHERE origin_id = NEW.id "         \
+        "); "                                                           \
+        "END")
+
+/**
+ * This trigger removes a row from moz_openpages_temp when open_count
+ * reaches 0.
+ *
+ * @note this should be kept up-to-date with the definition in
+ *       nsPlacesAutoComplete.js
+ */
+#  define CREATE_REMOVEOPENPAGE_CLEANUP_TRIGGER                            \
+    nsLiteralCString(                                                      \
+        "CREATE TEMPORARY TRIGGER moz_openpages_temp_afterupdate_trigger " \
+        "AFTER UPDATE OF open_count ON moz_openpages_temp FOR EACH ROW "   \
+        "WHEN NEW.open_count = 0 "                                         \
+        "BEGIN "                                                           \
+        "DELETE FROM moz_openpages_temp "                                  \
+        "WHERE url = NEW.url "                                             \
+        "AND userContextId = NEW.userContextId;"                           \
+        "END")
+
+/**
+ * Any bookmark operation should recalculate frecency, apart from place:
+ * queries.
+ */
+#  define IS_PLACE_QUERY                            \
+    " url_hash BETWEEN hash('place', 'prefix_lo') " \
+    "              AND hash('place', 'prefix_hi') "
+
+#  define CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERDELETE_TRIGGER                    \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_bookmarks_foreign_count_afterdelete_trigger " \
+        "AFTER DELETE ON moz_bookmarks FOR EACH ROW "                          \
+        "BEGIN "                                                               \
+        "UPDATE moz_places "                                                   \
+        "SET foreign_count = foreign_count - 1 "                               \
+        ",   recalc_frecency = NOT " IS_PLACE_QUERY                            \
+        ",   recalc_alt_frecency = NOT " IS_PLACE_QUERY                        \
+        "WHERE id = OLD.fk;"                                                   \
+        "END")
+
+/**
+ * Currently expiration skips anything with frecency = -1, since that is
+ * the default value for new page insertions. Unfortunately adding and
+ * immediately removing a bookmark will generate a page with frecency =
+ * -1 that would never be expired until visited. As a temporary
+ * workaround we set frecency to 1 on bookmark addition if it was set to
+ * -1. This is not elegant, but it will be fixed by Bug 1475582 once
+ * removing bookmarks will immediately take care of removing orphan
+ * pages. Note setting frecency resets recalc_frecency, so do it first.
+ */
+#  define CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERINSERT_TRIGGER                    \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_bookmarks_foreign_count_afterinsert_trigger " \
+        "AFTER INSERT ON moz_bookmarks FOR EACH ROW "                          \
+        "BEGIN "                                                               \
+        "SELECT store_last_inserted_id('moz_bookmarks', NEW.id); "             \
+        "SELECT note_sync_change() WHERE NEW.syncChangeCounter > 0; "          \
+        "UPDATE moz_places "                                                   \
+        "SET frecency = (CASE WHEN " IS_PLACE_QUERY                            \
+        "                THEN 0 ELSE 1 END) "                                  \
+        "WHERE frecency = -1 AND id = NEW.fk;"                                 \
+        "UPDATE moz_places "                                                   \
+        "SET foreign_count = foreign_count + 1 "                               \
+        ",   hidden = " IS_PLACE_QUERY                                         \
+        ",   recalc_frecency = NOT " IS_PLACE_QUERY                            \
+        ",   recalc_alt_frecency = NOT " IS_PLACE_QUERY                        \
+        "WHERE id = NEW.fk;"                                                   \
+        "END")
+
+#  define CREATE_BOOKMARKS_FOREIGNCOUNT_AFTERUPDATE_TRIGGER                    \
+    nsLiteralCString(                                                          \
+        "CREATE TEMP TRIGGER moz_bookmarks_foreign_count_afterupdate_trigger " \
+        "AFTER UPDATE OF fk, syncChangeCounter ON moz_bookmarks FOR EACH ROW " \
+        "BEGIN "                                                               \
+        "SELECT note_sync_change() "                                           \
+        "WHERE NEW.syncChangeCounter <> OLD.syncChangeCounter; "               \
+        "UPDATE moz_places "                                                   \
+        "SET foreign_count = foreign_count + 1 "                               \
+        ",   hidden = " IS_PLACE_QUERY                                         \
+        ",   recalc_frecency = NOT " IS_PLACE_QUERY                            \
+        ",   recalc_alt_frecency = NOT " IS_PLACE_QUERY                        \
+        "WHERE OLD.fk <> NEW.fk AND id = NEW.fk;"                              \
+        "UPDATE moz_places "                                                   \
+        "SET foreign_count = foreign_count - 1 "                               \
+        ",   recalc_frecency = NOT " IS_PLACE_QUERY                            \
+        ",   recalc_alt_frecency = NOT " IS_PLACE_QUERY                        \
+        "WHERE OLD.fk <> NEW.fk AND id = OLD.fk;"                              \
+        "END")
+
+#  define CREATE_KEYWORDS_FOREIGNCOUNT_AFTERDELETE_TRIGGER                    \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_keywords_foreign_count_afterdelete_trigger " \
+        "AFTER DELETE ON moz_keywords FOR EACH ROW "                          \
+        "BEGIN "                                                              \
+        "UPDATE moz_places "                                                  \
+        "SET foreign_count = foreign_count - 1 "                              \
+        "WHERE id = OLD.place_id;"                                            \
+        "END")
+
+#  define CREATE_KEYWORDS_FOREIGNCOUNT_AFTERINSERT_TRIGGER                    \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_keywords_foreign_count_afterinsert_trigger " \
+        "AFTER INSERT ON moz_keywords FOR EACH ROW "                          \
+        "BEGIN "                                                              \
+        "UPDATE moz_places "                                                  \
+        "SET foreign_count = foreign_count + 1 "                              \
+        "WHERE id = NEW.place_id;"                                            \
+        "END")
+
+#  define CREATE_KEYWORDS_FOREIGNCOUNT_AFTERUPDATE_TRIGGER                    \
+    nsLiteralCString(                                                         \
+        "CREATE TEMP TRIGGER moz_keywords_foreign_count_afterupdate_trigger " \
+        "AFTER UPDATE OF place_id ON moz_keywords FOR EACH ROW "              \
+        "BEGIN "                                                              \
+        "UPDATE moz_places "                                                  \
+        "SET foreign_count = foreign_count + 1 "                              \
+        "WHERE id = NEW.place_id; "                                           \
+        "UPDATE moz_places "                                                  \
+        "SET foreign_count = foreign_count - 1 "                              \
+        "WHERE id = OLD.place_id; "                                           \
+        "END")
+
+#  define CREATE_ICONS_AFTERINSERT_TRIGGER                      \
+    nsLiteralCString(                                           \
+        "CREATE TEMP TRIGGER moz_icons_afterinsert_v1_trigger " \
+        "AFTER INSERT ON moz_icons FOR EACH ROW "               \
+        "BEGIN "                                                \
+        "SELECT store_last_inserted_id('moz_icons', NEW.id); "  \
+        "END")
+
+#  define CREATE_BOOKMARKS_DELETED_AFTERINSERT_TRIGGER                      \
+    nsLiteralCString(                                                       \
+        "CREATE TEMP TRIGGER moz_bookmarks_deleted_afterinsert_v1_trigger " \
+        "AFTER INSERT ON moz_bookmarks_deleted FOR EACH ROW "               \
+        "BEGIN "                                                            \
+        "SELECT note_sync_change(); "                                       \
+        "END")
+
+#  define CREATE_BOOKMARKS_DELETED_AFTERDELETE_TRIGGER                      \
+    nsLiteralCString(                                                       \
+        "CREATE TEMP TRIGGER moz_bookmarks_deleted_afterdelete_v1_trigger " \
+        "AFTER DELETE ON moz_bookmarks_deleted FOR EACH ROW "               \
+        "BEGIN "                                                            \
+        "SELECT note_sync_change(); "                                       \
+        "END")
+
+// This trigger removes orphan search terms when interactions are
+// removed from the metadata table.
+#  define CREATE_PLACES_METADATA_AFTERDELETE_TRIGGER                   \
+    nsLiteralCString(                                                  \
+        "CREATE TEMP TRIGGER moz_places_metadata_afterdelete_trigger " \
+        "AFTER DELETE ON moz_places_metadata "                         \
+        "FOR EACH ROW "                                                \
+        "BEGIN "                                                       \
+        "DELETE FROM moz_places_metadata_search_queries "              \
+        "WHERE id = OLD.search_query_id AND NOT EXISTS ("              \
+        "SELECT id FROM moz_places_metadata "                          \
+        "WHERE search_query_id = OLD.search_query_id "                 \
+        "); "                                                          \
+        "END")
+
+// since moz_places_extra is really just storing json, there could be a
+// scenario where we have a valid row but empty json -- we should make sure
+// we have triggers to remove any such rows
+#  define CREATE_MOZ_PLACES_EXTRA_AFTERUPDATE_TRIGGER                 \
+    nsLiteralCString(                                                 \
+        "CREATE TEMP TRIGGER moz_places_extra_trigger "               \
+        "AFTER UPDATE ON moz_places_extra FOR EACH ROW "              \
+        "WHEN (NEW.sync_json = '' OR NEW.sync_json = '{}')"           \
+        "BEGIN "                                                      \
+        "DELETE FROM moz_places_extra WHERE place_id = NEW.place_id;" \
+        "END")
+
+#  define CREATE_MOZ_HISTORYVISITS_AFTERUPDATE_TRIGGER                       \
+    nsLiteralCString(                                                        \
+        "CREATE TEMP TRIGGER moz_historyvisits_extra_trigger "               \
+        "AFTER UPDATE ON moz_historyvisits_extra FOR EACH ROW "              \
+        "WHEN (NEW.sync_json = '' OR NEW.sync_json = '{}')"                  \
+        "BEGIN "                                                             \
+        "DELETE FROM moz_historyvisits_extra WHERE visit_id = NEW.visit_id;" \
+        "END")
+
+#endif  // __nsPlacesTriggers_h__
diff --git a/toolkit/components/places/tests/PlacesTestUtils.sys.mjs b/toolkit/components/places/tests/PlacesTestUtils.sys.mjs
new file mode 100644
index 0000000000..acd1152b44
--- /dev/null
+++ b/toolkit/components/places/tests/PlacesTestUtils.sys.mjs
@@ -0,0 +1,649 @@
+const lazy = {};
+ChromeUtils.defineESModuleGetters(lazy, {
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  TestUtils: "resource://testing-common/TestUtils.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(lazy, "PlacesFrecencyRecalculator", () => {
+  return Cc["@mozilla.org/places/frecency-recalculator;1"].getService(
+    Ci.nsIObserver
+  ).wrappedJSObject;
+});
+
+export var PlacesTestUtils = Object.freeze({
+  /**
+   * Asynchronously adds visits to a page.
+   *
+   * @param {*} aPlaceInfo
+   *        A string URL, nsIURI, Window.URL object, info object (explained
+   *        below), or an array of any of those.  Info objects describe the
+   *        visits to add more fully than URLs/URIs alone and look like this:
+   *
+   *          {
+   *            uri|url: href, URL or nsIURI of the page,
+   *            [optional] transition: one of the TRANSITION_* from nsINavHistoryService,
+   *            [optional] title: title of the page,
+   *            [optional] visitDate: visit date, either in microseconds from the epoch or as a date object
+   *            [optional] referrer: nsIURI of the referrer for this visit
+   *          }
+   *
+   * @return {Promise}
+   * @resolves When all visits have been added successfully.
+   * @rejects JavaScript exception.
+   */
+  async addVisits(placeInfo) {
+    let places = [];
+    let infos = [];
+
+    if (Array.isArray(placeInfo)) {
+      places.push(...placeInfo);
+    } else {
+      places.push(placeInfo);
+    }
+
+    // Create a PageInfo for each entry.
+    let seenUrls = new Set();
+    let lastStoredVisit;
+    for (let obj of places) {
+      let place;
+      if (
+        obj instanceof Ci.nsIURI ||
+        URL.isInstance(obj) ||
+        typeof obj == "string"
+      ) {
+        place = { uri: obj };
+      } else if (typeof obj == "object" && (obj.uri || obj.url)) {
+        place = obj;
+      } else {
+        throw new Error("Unsupported type passed to addVisits");
+      }
+
+      let referrer = place.referrer
+        ? lazy.PlacesUtils.toURI(place.referrer)
+        : null;
+      let info = { url: place.uri || place.url };
+      let spec =
+        info.url instanceof Ci.nsIURI ? info.url.spec : new URL(info.url).href;
+      info.title = "title" in place ? place.title : "test visit for " + spec;
+      let visitDate = place.visitDate;
+      if (visitDate) {
+        if (visitDate.constructor.name != "Date") {
+          // visitDate should be in microseconds. It's easy to do the wrong thing
+          // and pass milliseconds, so we lazily check for that.
+          // While it's not easily distinguishable, since both are integers, we
+          // can check if the value is very far in the past, and assume it's
+          // probably a mistake.
+          if (visitDate <= Date.now()) {
+            throw new Error(
+              "AddVisits expects a Date object or _micro_seconds!"
+            );
+          }
+          visitDate = lazy.PlacesUtils.toDate(visitDate);
+        }
+      } else {
+        visitDate = new Date();
+      }
+      info.visits = [
+        {
+          transition: place.transition,
+          date: visitDate,
+          referrer,
+        },
+      ];
+      seenUrls.add(info.url);
+      infos.push(info);
+      if (
+        !place.transition ||
+        place.transition != lazy.PlacesUtils.history.TRANSITIONS.EMBED
+      ) {
+        lastStoredVisit = info;
+      }
+    }
+    await lazy.PlacesUtils.history.insertMany(infos);
+    if (seenUrls.size > 1) {
+      // If there's only one URL then history has updated frecency already,
+      // otherwise we must force a recalculation.
+      await lazy.PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+    }
+    if (lastStoredVisit) {
+      await lazy.TestUtils.waitForCondition(
+        () => lazy.PlacesUtils.history.fetch(lastStoredVisit.url),
+        "Ensure history has been updated and is visible to read-only connections"
+      );
+    }
+  },
+
+  /*
+   * Add Favicons
+   *
+   * @param {Map} faviconURLs  keys are page URLs, values are their
+   *                           associated favicon URLs.
+   */
+
+  async addFavicons(faviconURLs) {
+    let faviconPromises = [];
+
+    // If no favicons were provided, we do not want to continue on
+    if (!faviconURLs) {
+      throw new Error("No favicon URLs were provided");
+    }
+    for (let [key, val] of faviconURLs) {
+      if (!val) {
+        throw new Error("URL does not exist");
+      }
+      faviconPromises.push(
+        new Promise((resolve, reject) => {
+          let uri = Services.io.newURI(key);
+          let faviconURI = Services.io.newURI(val);
+          try {
+            lazy.PlacesUtils.favicons.setAndFetchFaviconForPage(
+              uri,
+              faviconURI,
+              false,
+              lazy.PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+              resolve,
+              Services.scriptSecurityManager.getSystemPrincipal()
+            );
+          } catch (ex) {
+            reject(ex);
+          }
+        })
+      );
+    }
+    await Promise.all(faviconPromises);
+  },
+
+  /**
+   * Clears any favicons stored in the database.
+   */
+  async clearFavicons() {
+    return new Promise(resolve => {
+      Services.obs.addObserver(function observer() {
+        Services.obs.removeObserver(observer, "places-favicons-expired");
+        resolve();
+      }, "places-favicons-expired");
+      lazy.PlacesUtils.favicons.expireAllFavicons();
+    });
+  },
+
+  /**
+   * Adds a bookmark to the database. This should only be used when you need to
+   * add keywords. Otherwise, use `PlacesUtils.bookmarks.insert()`.
+   * @param {string} aBookmarkObj.uri
+   * @param {string} [aBookmarkObj.title]
+   * @param {string} [aBookmarkObj.keyword]
+   */
+  async addBookmarkWithDetails(aBookmarkObj) {
+    await lazy.PlacesUtils.bookmarks.insert({
+      parentGuid: lazy.PlacesUtils.bookmarks.unfiledGuid,
+      title: aBookmarkObj.title || "A bookmark",
+      url: aBookmarkObj.uri,
+    });
+
+    if (aBookmarkObj.keyword) {
+      await lazy.PlacesUtils.keywords.insert({
+        keyword: aBookmarkObj.keyword,
+        url:
+          aBookmarkObj.uri instanceof Ci.nsIURI
+            ? aBookmarkObj.uri.spec
+            : aBookmarkObj.uri,
+        postData: aBookmarkObj.postData,
+      });
+    }
+
+    if (aBookmarkObj.tags) {
+      let uri =
+        aBookmarkObj.uri instanceof Ci.nsIURI
+          ? aBookmarkObj.uri
+          : Services.io.newURI(aBookmarkObj.uri);
+      lazy.PlacesUtils.tagging.tagURI(uri, aBookmarkObj.tags);
+    }
+  },
+
+  /**
+   * Waits for all pending async statements on the default connection.
+   *
+   * @return {Promise}
+   * @resolves When all pending async statements finished.
+   * @rejects Never.
+   *
+   * @note The result is achieved by asynchronously executing a query requiring
+   *       a write lock.  Since all statements on the same connection are
+   *       serialized, the end of this write operation means that all writes are
+   *       complete.  Note that WAL makes so that writers don't block readers, but
+   *       this is a problem only across different connections.
+   */
+  promiseAsyncUpdates() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "promiseAsyncUpdates",
+      async function (db) {
+        try {
+          await db.executeCached("BEGIN EXCLUSIVE");
+          await db.executeCached("COMMIT");
+        } catch (ex) {
+          // If we fail to start a transaction, it's because there is already one.
+          // In such a case we should not try to commit the existing transaction.
+        }
+      }
+    );
+  },
+
+  /**
+   * Asynchronously checks if an address is found in the database.
+   * @param aURI
+   *        nsIURI or address to look for.
+   *
+   * @return {Promise}
+   * @resolves Returns true if the page is found.
+   * @rejects JavaScript exception.
+   */
+  async isPageInDB(aURI) {
+    return (
+      (await this.getDatabaseValue("moz_places", "id", { url: aURI })) !==
+      undefined
+    );
+  },
+
+  /**
+   * Asynchronously checks how many visits exist for a specified page.
+   * @param aURI
+   *        nsIURI or address to look for.
+   *
+   * @return {Promise}
+   * @resolves Returns the number of visits found.
+   * @rejects JavaScript exception.
+   */
+  async visitsInDB(aURI) {
+    let url = aURI instanceof Ci.nsIURI ? aURI.spec : aURI;
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `SELECT count(*) FROM moz_historyvisits v
+       JOIN moz_places h ON h.id = v.place_id
+       WHERE url_hash = hash(:url) AND url = :url`,
+      { url }
+    );
+    return rows[0].getResultByIndex(0);
+  },
+
+  /**
+   * Marks all syncable bookmarks as synced by setting their sync statuses to
+   * "NORMAL", resetting their change counters, and removing all tombstones.
+   * Used by tests to avoid calling `PlacesSyncUtils.bookmarks.pullChanges`
+   * and `PlacesSyncUtils.bookmarks.pushChanges`.
+   *
+   * @resolves When all bookmarks have been updated.
+   * @rejects JavaScript exception.
+   */
+  markBookmarksAsSynced() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesTestUtils: markBookmarksAsSynced",
+      function (db) {
+        return db.executeTransaction(async function () {
+          await db.executeCached(
+            `WITH RECURSIVE
+           syncedItems(id) AS (
+             SELECT b.id FROM moz_bookmarks b
+             WHERE b.guid IN ('menu________', 'toolbar_____', 'unfiled_____',
+                              'mobile______')
+             UNION ALL
+             SELECT b.id FROM moz_bookmarks b
+             JOIN syncedItems s ON b.parent = s.id
+           )
+           UPDATE moz_bookmarks
+           SET syncChangeCounter = 0,
+               syncStatus = :syncStatus
+           WHERE id IN syncedItems`,
+            { syncStatus: lazy.PlacesUtils.bookmarks.SYNC_STATUS.NORMAL }
+          );
+          await db.executeCached("DELETE FROM moz_bookmarks_deleted");
+        });
+      }
+    );
+  },
+
+  /**
+   * Sets sync fields for multiple bookmarks.
+   * @param aStatusInfos
+   *        One or more objects with the following properties:
+   *          { [required] guid: The bookmark's GUID,
+   *            syncStatus: An `nsINavBookmarksService::SYNC_STATUS_*` constant,
+   *            syncChangeCounter: The sync change counter value,
+   *            lastModified: The last modified time,
+   *            dateAdded: The date added time.
+   *          }
+   *
+   * @resolves When all bookmarks have been updated.
+   * @rejects JavaScript exception.
+   */
+  setBookmarkSyncFields(...aFieldInfos) {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesTestUtils: setBookmarkSyncFields",
+      function (db) {
+        return db.executeTransaction(async function () {
+          for (let info of aFieldInfos) {
+            if (!lazy.PlacesUtils.isValidGuid(info.guid)) {
+              throw new Error(`Invalid GUID: ${info.guid}`);
+            }
+            await db.executeCached(
+              `UPDATE moz_bookmarks
+             SET syncStatus = IFNULL(:syncStatus, syncStatus),
+                 syncChangeCounter = IFNULL(:syncChangeCounter, syncChangeCounter),
+                 lastModified = IFNULL(:lastModified, lastModified),
+                 dateAdded = IFNULL(:dateAdded, dateAdded)
+             WHERE guid = :guid`,
+              {
+                guid: info.guid,
+                syncChangeCounter: info.syncChangeCounter,
+                syncStatus: "syncStatus" in info ? info.syncStatus : null,
+                lastModified:
+                  "lastModified" in info
+                    ? lazy.PlacesUtils.toPRTime(info.lastModified)
+                    : null,
+                dateAdded:
+                  "dateAdded" in info
+                    ? lazy.PlacesUtils.toPRTime(info.dateAdded)
+                    : null,
+              }
+            );
+          }
+        });
+      }
+    );
+  },
+
+  async fetchBookmarkSyncFields(...aGuids) {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let results = [];
+    for (let guid of aGuids) {
+      let rows = await db.executeCached(
+        `
+        SELECT syncStatus, syncChangeCounter, lastModified, dateAdded
+        FROM moz_bookmarks
+        WHERE guid = :guid`,
+        { guid }
+      );
+      if (!rows.length) {
+        throw new Error(`Bookmark ${guid} does not exist`);
+      }
+      results.push({
+        guid,
+        syncStatus: rows[0].getResultByName("syncStatus"),
+        syncChangeCounter: rows[0].getResultByName("syncChangeCounter"),
+        lastModified: lazy.PlacesUtils.toDate(
+          rows[0].getResultByName("lastModified")
+        ),
+        dateAdded: lazy.PlacesUtils.toDate(
+          rows[0].getResultByName("dateAdded")
+        ),
+      });
+    }
+    return results;
+  },
+
+  async fetchSyncTombstones() {
+    let db = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(`
+      SELECT guid, dateRemoved
+      FROM moz_bookmarks_deleted
+      ORDER BY guid`);
+    return rows.map(row => ({
+      guid: row.getResultByName("guid"),
+      dateRemoved: lazy.PlacesUtils.toDate(row.getResultByName("dateRemoved")),
+    }));
+  },
+
+  /**
+   * Returns a promise that waits until happening Places events specified by
+   * notification parameter.
+   *
+   * @param {string} notification
+   *        Available values are:
+   *          bookmark-added
+   *          bookmark-removed
+   *          bookmark-moved
+   *          bookmark-guid_changed
+   *          bookmark-keyword_changed
+   *          bookmark-tags_changed
+   *          bookmark-time_changed
+   *          bookmark-title_changed
+   *          bookmark-url_changed
+   *          favicon-changed
+   *          history-cleared
+   *          page-removed
+   *          page-title-changed
+   *          page-visited
+   *          pages-rank-changed
+   *          purge-caches
+   * @param {Function} conditionFn [optional]
+   *        If need some more condition to wait, please use conditionFn.
+   *        This is an optional, but if set, should returns true when the wait
+   *        condition is met.
+   * @return {Promise}
+   *         A promise that resolved if the wait condition is met.
+   *         The resolved value is an array of PlacesEvent object.
+   */
+  waitForNotification(notification, conditionFn) {
+    return new Promise(resolve => {
+      function listener(events) {
+        if (!conditionFn || conditionFn(events)) {
+          PlacesObservers.removeListener([notification], listener);
+          resolve(events);
+        }
+      }
+      PlacesObservers.addListener([notification], listener);
+    });
+  },
+
+  /**
+   * A debugging helper that dumps the contents of an SQLite table.
+   *
+   * @param {String} table
+   *        The table name.
+   * @param {Sqlite.OpenedConnection} [db]
+   *        The mirror database connection.
+   * @param {String[]} [columns]
+   *        Clumns to be printed, defaults to all.
+   */
+  async dumpTable({ table, db, columns }) {
+    if (!table) {
+      throw new Error("Must pass a `table` name");
+    }
+    if (!db) {
+      db = await lazy.PlacesUtils.promiseDBConnection();
+    }
+    if (!columns) {
+      columns = (await db.execute(`PRAGMA table_info('${table}')`)).map(r =>
+        r.getResultByName("name")
+      );
+    }
+    let results = [columns.join("\t")];
+
+    let rows = await db.execute(`SELECT ${columns.join()} FROM ${table}`);
+    dump(`>> Table ${table} contains ${rows.length} rows\n`);
+
+    for (let row of rows) {
+      let numColumns = row.numEntries;
+      let rowValues = [];
+      for (let i = 0; i < numColumns; ++i) {
+        let value = "N/A";
+        switch (row.getTypeOfIndex(i)) {
+          case Ci.mozIStorageValueArray.VALUE_TYPE_NULL:
+            value = "NULL";
+            break;
+          case Ci.mozIStorageValueArray.VALUE_TYPE_INTEGER:
+            value = row.getInt64(i);
+            break;
+          case Ci.mozIStorageValueArray.VALUE_TYPE_FLOAT:
+            value = row.getDouble(i);
+            break;
+          case Ci.mozIStorageValueArray.VALUE_TYPE_TEXT:
+            value = JSON.stringify(row.getString(i));
+            break;
+        }
+        rowValues.push(value.toString().padStart(columns[i].length, " "));
+      }
+      results.push(rowValues.join("\t"));
+    }
+    results.push("\n");
+    dump(results.join("\n"));
+  },
+
+  /**
+   * Removes all stored metadata.
+   */
+  clearMetadata() {
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "PlacesTestUtils: clearMetadata",
+      async db => {
+        await db.execute(`DELETE FROM moz_meta`);
+        lazy.PlacesUtils.metadata.cache.clear();
+      }
+    );
+  },
+
+  /**
+   * Clear moz_inputhistory table.
+   */
+  async clearInputHistory() {
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "test:clearInputHistory",
+      db => {
+        return db.executeCached("DELETE FROM moz_inputhistory");
+      }
+    );
+  },
+
+  /**
+   * Clear moz_historyvisits table.
+   */
+  async clearHistoryVisits() {
+    await lazy.PlacesUtils.withConnectionWrapper(
+      "test:clearHistoryVisits",
+      db => {
+        return db.executeCached("DELETE FROM moz_historyvisits");
+      }
+    );
+  },
+
+  /**
+   * Compares 2 place: URLs ignoring the order of their params.
+   * @param url1 First URL to compare
+   * @param url2 Second URL to compare
+   * @return whether the URLs are the same
+   */
+  ComparePlacesURIs(url1, url2) {
+    url1 = url1 instanceof Ci.nsIURI ? url1.spec : new URL(url1);
+    if (url1.protocol != "place:") {
+      throw new Error("Expected a place: uri, got " + url1.href);
+    }
+    url2 = url2 instanceof Ci.nsIURI ? url2.spec : new URL(url2);
+    if (url2.protocol != "place:") {
+      throw new Error("Expected a place: uri, got " + url2.href);
+    }
+    let tokens1 = url1.pathname.split("&").sort().join("&");
+    let tokens2 = url2.pathname.split("&").sort().join("&");
+    if (tokens1 != tokens2) {
+      dump(`Failed comparison between:\n${tokens1}\n${tokens2}\n`);
+      return false;
+    }
+    return true;
+  },
+
+  /**
+   * Retrieves a single value from a specified field in a database table, based
+   * on the given conditions.
+   * @param {string} table - The name of the database table to query.
+   * @param {string} field - The name of the field to retrieve a value from.
+   * @param {Object} [conditions] - An object containing the conditions to
+   * filter the query results. The keys represent the names of the columns to
+   * filter by, and the values represent the filter values.
+   * @return {Promise} A Promise that resolves to the value of the specified
+   * field from the database table, or null if the query returns no results.
+   * @throws If more than one result is found for the given conditions.
+   */
+  async getDatabaseValue(table, field, conditions = {}) {
+    let { fragment: where, params } = this._buildWhereClause(table, conditions);
+    let query = `SELECT ${field} FROM ${table} ${where}`;
+    let conn = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await conn.executeCached(query, params);
+    if (rows.length > 1) {
+      throw new Error(
+        "getDatabaseValue doesn't support returning multiple results"
+      );
+    }
+    return rows[0]?.getResultByIndex(0);
+  },
+
+  /**
+   * Updates specified fields in a database table, based on the given
+   * conditions.
+   * @param {string} table - The name of the database table to add to.
+   * @param {string} fields - an object with field, value pairs
+   * @param {Object} [conditions] - An object containing the conditions to filter
+   * the query results. The keys represent the names of the columns to filter
+   * by, and the values represent the filter values.
+   * @return {Promise} A Promise that resolves to the number of affected rows.
+   * @throws If no rows were affected.
+   */
+  async updateDatabaseValues(table, fields, conditions = {}) {
+    let { fragment: where, params } = this._buildWhereClause(table, conditions);
+    let query = `UPDATE ${table} SET ${Object.keys(fields)
+      .map(f => f + " = :" + f)
+      .join()} ${where} RETURNING rowid`;
+    params = Object.assign(fields, params);
+    return lazy.PlacesUtils.withConnectionWrapper(
+      "setDatabaseValue",
+      async conn => {
+        let rows = await conn.executeCached(query, params);
+        if (!rows.length) {
+          throw new Error("setDatabaseValue didn't update any value");
+        }
+        return rows.length;
+      }
+    );
+  },
+
+  async promiseItemId(guid) {
+    return this.getDatabaseValue("moz_bookmarks", "id", { guid });
+  },
+
+  async promiseItemGuid(id) {
+    return this.getDatabaseValue("moz_bookmarks", "guid", { id });
+  },
+
+  async promiseManyItemIds(guids) {
+    let conn = await lazy.PlacesUtils.promiseDBConnection();
+    let rows = await conn.executeCached(`
+      SELECT guid, id FROM moz_bookmarks WHERE guid IN (${guids
+        .map(guid => "'" + guid + "'")
+        .join()}
+      )`);
+    return new Map(
+      rows.map(r => [r.getResultByName("guid"), r.getResultByName("id")])
+    );
+  },
+
+  _buildWhereClause(table, conditions) {
+    let fragments = [];
+    let params = {};
+    for (let [column, value] of Object.entries(conditions)) {
+      if (column == "url") {
+        if (value instanceof Ci.nsIURI) {
+          value = value.spec;
+        } else if (URL.isInstance(value)) {
+          value = value.href;
+        }
+      }
+      if (column == "url" && table == "moz_places") {
+        fragments.push("url_hash = hash(:url) AND url = :url");
+      } else {
+        fragments.push(`${column} = :${column}`);
+      }
+      params[column] = value;
+    }
+    return {
+      fragment: fragments.length ? `WHERE ${fragments.join(" AND ")}` : "",
+      params,
+    };
+  },
+});
diff --git a/toolkit/components/places/tests/bookmarks/bookmarks_long_tag.json b/toolkit/components/places/tests/bookmarks/bookmarks_long_tag.json
new file mode 100644
index 0000000000..25fef61eb2
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/bookmarks_long_tag.json
@@ -0,0 +1,55 @@
+{
+  "guid": "root________",
+  "index": 0,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "dateAdded": 1554906792778,
+  "lastModified": 1554906792778,
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "unfiled_____",
+      "index": 0,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "dateAdded": 1554906792778,
+      "lastModified": 1554906792778,
+      "root": "unfiledBookmarksFolder",
+      "children": [
+        {
+          "guid": "___guid1____",
+          "index": 0,
+          "id": 3,
+          "charset": "UTF-16",
+          "tags": "tag0",
+          "type": "text/x-moz-place",
+          "dateAdded": 1554906792778,
+          "lastModified": 1554906792778,
+          "uri": "http://test0.com/"
+        },
+        {
+          "guid": "___guid2____",
+          "index": 1,
+          "id": 4,
+          "charset": "UTF-16",
+          "tags": "tag1,a0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789",
+          "type": "text/x-moz-place",
+          "dateAdded": 1554906792778,
+          "lastModified": 1554906792778,
+          "uri": "http://test1.com/"
+        },
+        {
+          "guid": "___guid3____",
+          "index": 2,
+          "id": 5,
+          "charset": "UTF-16",
+          "tags": "tag2",
+          "type": "text/x-moz-place",
+          "dateAdded": 1554906792778,
+          "lastModified": 1554906792778,
+          "uri": "http://test2.com/"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/bookmarks/head_bookmarks.js b/toolkit/components/places/tests/bookmarks/head_bookmarks.js
new file mode 100644
index 0000000000..dc790ee6a6
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/head_bookmarks.js
@@ -0,0 +1,157 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+function expectPlacesObserverNotifications(
+  types,
+  checkAllArgs = true,
+  skipDescendants = false
+) {
+  let notifications = [];
+  let listener = events => {
+    for (let event of events) {
+      switch (event.type) {
+        case "bookmark-added":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            parentId: event.parentId,
+            index: event.index,
+            url: event.url || undefined,
+            title: event.title,
+            dateAdded: new Date(event.dateAdded),
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            isTagging: event.isTagging,
+          });
+          break;
+        case "bookmark-removed":
+          if (
+            !(
+              skipDescendants &&
+              event.isDescendantRemoval &&
+              !PlacesUtils.bookmarks.userContentRoots.includes(event.parentGuid)
+            )
+          ) {
+            if (checkAllArgs) {
+              notifications.push({
+                type: event.type,
+                id: event.id,
+                itemType: event.itemType,
+                parentId: event.parentId,
+                index: event.index,
+                url: event.url || null,
+                guid: event.guid,
+                parentGuid: event.parentGuid,
+                source: event.source,
+                isTagging: event.isTagging,
+              });
+            } else {
+              notifications.push({
+                type: event.type,
+                guid: event.guid,
+              });
+            }
+          }
+          break;
+        case "bookmark-moved":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            url: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            index: event.index,
+            oldParentGuid: event.oldParentGuid,
+            oldIndex: event.oldIndex,
+            isTagging: event.isTagging,
+            title: event.title,
+            tags: event.tags,
+            frecency: event.frecency,
+            hidden: event.hidden,
+            visitCount: event.visitCount,
+            dateAdded: event.dateAdded,
+            lastVisitDate: event.lastVisitDate,
+          });
+          break;
+        case "bookmark-tags-changed":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            url: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            tags: event.tags,
+            lastModified: new Date(event.lastModified),
+            source: event.source,
+            isTagging: event.isTagging,
+          });
+          break;
+        case "bookmark-time-changed":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            url: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            dateAdded: new Date(event.dateAdded),
+            lastModified: new Date(event.lastModified),
+            source: event.source,
+            isTagging: event.isTagging,
+          });
+          break;
+        case "bookmark-title-changed":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            url: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            title: event.title,
+            lastModified: new Date(event.lastModified),
+            source: event.source,
+            isTagging: event.isTagging,
+          });
+          break;
+        case "bookmark-url-changed":
+          notifications.push({
+            type: event.type,
+            id: event.id,
+            itemType: event.itemType,
+            url: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            isTagging: event.isTagging,
+            lastModified: new Date(event.lastModified),
+          });
+          break;
+      }
+    }
+  };
+  PlacesUtils.observers.addListener(types, listener);
+  return {
+    check(expectedNotifications) {
+      PlacesUtils.observers.removeListener(types, listener);
+      Assert.deepEqual(notifications, expectedNotifications);
+    },
+  };
+}
diff --git a/toolkit/components/places/tests/bookmarks/test_1016953-renaming-uncompressed.js b/toolkit/components/places/tests/bookmarks/test_1016953-renaming-uncompressed.js
new file mode 100644
index 0000000000..3f74430296
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_1016953-renaming-uncompressed.js
@@ -0,0 +1,119 @@
+/* Bug 1016953 - When a previous bookmark backup exists with the same hash
+regardless of date, an automatic backup should attempt to either rename it to
+today's date if the backup was for an old date or leave it alone if it was for
+the same date. However if the file ext was json it will accidentally rename it
+to jsonlz4 while keeping the json contents
+*/
+
+add_task(async function test_same_date_same_hash() {
+  // If old file has been created on the same date and has the same hash
+  // the file should be left alone
+  let backupFolder = await PlacesBackups.getBackupFolder();
+  // Save to profile dir to obtain hash and nodeCount to append to filename
+  let tempPath = PathUtils.join(
+    PathUtils.profileDir,
+    "bug10169583_bookmarks.json"
+  );
+  let { count, hash } = await BookmarkJSONUtils.exportToFile(tempPath);
+
+  // Save JSON file in backup folder with hash appended
+  let dateObj = new Date();
+  let filename =
+    "bookmarks-" +
+    PlacesBackups.toISODateString(dateObj) +
+    "_" +
+    count +
+    "_" +
+    hash +
+    ".json";
+  let backupFile = PathUtils.join(backupFolder, filename);
+  await IOUtils.move(tempPath, backupFile);
+
+  // Force a compressed backup which fallbacks to rename
+  await PlacesBackups.create();
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+  // check to ensure not renamed to jsonlz4
+  Assert.equal(mostRecentBackupFile, backupFile);
+  // inspect contents and check if valid json
+  info("Check is valid JSON");
+  // We initially wrote an uncompressed file, and although a backup was triggered
+  // it did not rewrite the file, so this is uncompressed.
+  await IOUtils.readJSON(mostRecentBackupFile);
+
+  // Cleanup
+  await IOUtils.remove(backupFile);
+  await IOUtils.remove(tempPath);
+  PlacesBackups._backupFiles = null; // To force re-cache of backupFiles
+});
+
+add_task(async function test_same_date_diff_hash() {
+  // If the old file has been created on the same date, but has a different hash
+  // the existing file should be overwritten with the newer compressed version
+  let backupFolder = await PlacesBackups.getBackupFolder();
+  let tempPath = PathUtils.join(
+    PathUtils.profileDir,
+    "bug10169583_bookmarks.json"
+  );
+  let { count } = await BookmarkJSONUtils.exportToFile(tempPath);
+  let dateObj = new Date();
+  let filename =
+    "bookmarks-" +
+    PlacesBackups.toISODateString(dateObj) +
+    "_" +
+    count +
+    "_differentHash==.json";
+  let backupFile = PathUtils.join(backupFolder, filename);
+  await IOUtils.move(tempPath, backupFile);
+  await PlacesBackups.create(); // Force compressed backup
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+
+  // Decode lz4 compressed file to json and check if json is valid
+  info("Check is valid JSON");
+  await IOUtils.readJSON(mostRecentBackupFile, { decompress: true });
+
+  // Cleanup
+  await IOUtils.remove(mostRecentBackupFile);
+  await IOUtils.remove(tempPath);
+  PlacesBackups._backupFiles = null; // To force re-cache of backupFiles
+});
+
+add_task(async function test_diff_date_same_hash() {
+  // If the old file has been created on an older day but has the same hash
+  // it should be renamed with today's date without altering the contents.
+  let backupFolder = await PlacesBackups.getBackupFolder();
+  let tempPath = PathUtils.join(
+    PathUtils.profileDir,
+    "bug10169583_bookmarks.json"
+  );
+  let { count, hash } = await BookmarkJSONUtils.exportToFile(tempPath);
+  let oldDate = new Date(2014, 1, 1);
+  let curDate = new Date();
+  let oldFilename =
+    "bookmarks-" +
+    PlacesBackups.toISODateString(oldDate) +
+    "_" +
+    count +
+    "_" +
+    hash +
+    ".json";
+  let newFilename =
+    "bookmarks-" +
+    PlacesBackups.toISODateString(curDate) +
+    "_" +
+    count +
+    "_" +
+    hash +
+    ".json";
+  let backupFile = PathUtils.join(backupFolder, oldFilename);
+  let newBackupFile = PathUtils.join(backupFolder, newFilename);
+  await IOUtils.move(tempPath, backupFile);
+
+  // Ensure file has been renamed correctly
+  await PlacesBackups.create();
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+  Assert.equal(mostRecentBackupFile, newBackupFile);
+
+  // Cleanup
+  await IOUtils.remove(mostRecentBackupFile);
+  await IOUtils.remove(tempPath);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_1017502-bookmarks_foreign_count.js b/toolkit/components/places/tests/bookmarks/test_1017502-bookmarks_foreign_count.js
new file mode 100644
index 0000000000..47955a4ea4
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_1017502-bookmarks_foreign_count.js
@@ -0,0 +1,117 @@
+/* -*- tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Bug 1017502 - Add a foreign_count column to moz_places
+This tests, tests the triggers that adjust the foreign_count when a bookmark is
+added or removed and also the maintenance task to fix wrong counts.
+*/
+
+const T_URI = Services.io.newURI(
+  "https://www.mozilla.org/firefox/nightly/firstrun/"
+);
+
+async function getForeignCountForURL(conn, url) {
+  await PlacesTestUtils.promiseAsyncUpdates();
+  url = url instanceof Ci.nsIURI ? url.spec : url;
+  let rows = await conn.executeCached(
+    `SELECT foreign_count FROM moz_places WHERE url_hash = hash(:t_url)
+                                            AND url = :t_url`,
+    { t_url: url }
+  );
+  return rows[0].getResultByName("foreign_count");
+}
+
+add_task(async function add_remove_change_bookmark_test() {
+  let conn = await PlacesUtils.promiseDBConnection();
+
+  // Simulate a visit to the url
+  await PlacesTestUtils.addVisits(T_URI);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 0);
+
+  // Add 1st bookmark which should increment foreign_count by 1
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "First Run",
+    url: T_URI,
+  });
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 1);
+
+  // Add 2nd bookmark
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "First Run",
+    url: T_URI,
+  });
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 2);
+
+  // Remove 2nd bookmark which should decrement foreign_count by 1
+  await PlacesUtils.bookmarks.remove(bm2);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 1);
+
+  // Change first bookmark's URI
+  const URI2 = Services.io.newURI("http://www.mozilla.org");
+  bm1.url = URI2;
+  bm1 = await PlacesUtils.bookmarks.update(bm1);
+  // Check foreign count for original URI
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 0);
+  // Check foreign count for new URI
+  Assert.equal(await getForeignCountForURL(conn, URI2), 1);
+
+  // Cleanup - Remove changed bookmark
+  await PlacesUtils.bookmarks.remove(bm1);
+  Assert.equal(await getForeignCountForURL(conn, URI2), 0);
+});
+
+add_task(async function maintenance_foreign_count_test() {
+  let conn = await PlacesUtils.promiseDBConnection();
+
+  // Simulate a visit to the url
+  await PlacesTestUtils.addVisits(T_URI);
+
+  // Adjust the foreign_count for the added entry to an incorrect value
+  await new Promise(resolve => {
+    let stmt = DBConn().createAsyncStatement(
+      `UPDATE moz_places SET foreign_count = 10 WHERE url_hash = hash(:t_url)
+                                                  AND url = :t_url `
+    );
+    stmt.params.t_url = T_URI.spec;
+    stmt.executeAsync({
+      handleCompletion() {
+        resolve();
+      },
+    });
+    stmt.finalize();
+  });
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 10);
+
+  // Run maintenance
+  const { PlacesDBUtils } = ChromeUtils.importESModule(
+    "resource://gre/modules/PlacesDBUtils.sys.mjs"
+  );
+  await PlacesDBUtils.maintenanceOnIdle();
+
+  // Check if the foreign_count has been adjusted to the correct value
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 0);
+});
+
+add_task(async function add_remove_tags_test() {
+  let conn = await PlacesUtils.promiseDBConnection();
+
+  await PlacesTestUtils.addVisits(T_URI);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 0);
+
+  // Check foreign count incremented by 1 for a single tag
+  PlacesUtils.tagging.tagURI(T_URI, ["test tag"]);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 1);
+
+  // Check foreign count is incremented by 2 for two tags
+  PlacesUtils.tagging.tagURI(T_URI, ["one", "two"]);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 3);
+
+  // Check foreign count is set to 0 when all tags are removed
+  PlacesUtils.tagging.untagURI(T_URI, ["test tag", "one", "two"]);
+  Assert.equal(await getForeignCountForURL(conn, T_URI), 0);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_1129529.js b/toolkit/components/places/tests/bookmarks/test_1129529.js
new file mode 100644
index 0000000000..8fa4731823
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_1129529.js
@@ -0,0 +1,24 @@
+// Test that importing bookmark data where a bookmark has a tag longer than 100
+// chars imports everything except the tags for that bookmark.
+add_task(async function () {
+  let bookmarksFile = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks_long_tag.json"
+  );
+  let bookmarksUrl = PathUtils.toFileURI(bookmarksFile);
+
+  await BookmarkJSONUtils.importFromURL(bookmarksUrl);
+
+  let [bookmarks] = await PlacesBackups.getBookmarksTree();
+  let unsortedBookmarks = bookmarks.children[2].children;
+  Assert.equal(unsortedBookmarks.length, 3);
+
+  for (let i = 0; i < unsortedBookmarks.length; ++i) {
+    let bookmark = unsortedBookmarks[i];
+    Assert.equal(bookmark.charset, "UTF-16");
+    Assert.equal(bookmark.dateAdded, 1554906792000);
+    Assert.equal(bookmark.lastModified, 1554906792000);
+    Assert.equal(bookmark.uri, `http://test${i}.com/`);
+    Assert.equal(bookmark.tags, `tag${i}`);
+  }
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_384228.js b/toolkit/components/places/tests/bookmarks/test_384228.js
new file mode 100644
index 0000000000..0db46353b7
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_384228.js
@@ -0,0 +1,93 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * test querying for bookmarks in multiple folders.
+ */
+add_task(async function search_bookmark_in_folder() {
+  let testFolder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bug 384228 test folder 1",
+  });
+  Assert.equal(testFolder1.index, 0);
+
+  let testFolder2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bug 384228 test folder 2",
+  });
+  Assert.equal(testFolder2.index, 1);
+
+  let testFolder3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bug 384228 test folder 3",
+  });
+  Assert.equal(testFolder3.index, 2);
+
+  let b1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder1.guid,
+    url: "http://foo.tld/",
+    title: "title b1 (folder 1)",
+  });
+  Assert.equal(b1.index, 0);
+
+  let b2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder1.guid,
+    url: "http://foo.tld/",
+    title: "title b2 (folder 1)",
+  });
+  Assert.equal(b2.index, 1);
+
+  let b3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder2.guid,
+    url: "http://foo.tld/",
+    title: "title b3 (folder 2)",
+  });
+  Assert.equal(b3.index, 0);
+
+  let b4 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder3.guid,
+    url: "http://foo.tld/",
+    title: "title b4 (folder 3)",
+  });
+  Assert.equal(b4.index, 0);
+
+  // also test recursive search
+  let testFolder1_1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder1.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bug 384228 test folder 1.1",
+  });
+  Assert.equal(testFolder1_1.index, 2);
+
+  let b5 = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder1_1.guid,
+    url: "http://foo.tld/",
+    title: "title b5 (folder 1.1)",
+  });
+  Assert.equal(b5.index, 0);
+
+  // query folder 1, folder 2 and get 4 bookmarks
+  let hs = PlacesUtils.history;
+  let options = hs.getNewQueryOptions();
+  let query = hs.getNewQuery();
+  query.searchTerms = "title";
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  query.setParents([testFolder1.guid, testFolder2.guid]);
+  let rootNode = hs.executeQuery(query, options).root;
+  rootNode.containerOpen = true;
+
+  // should not match item from folder 3
+  Assert.equal(rootNode.childCount, 4);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b1.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b3.guid);
+  Assert.equal(rootNode.getChild(3).bookmarkGuid, b5.guid);
+
+  rootNode.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_385829.js b/toolkit/components/places/tests/bookmarks/test_385829.js
new file mode 100644
index 0000000000..9de7c6da17
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_385829.js
@@ -0,0 +1,180 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function search_bookmark_by_lastModified_dateDated() {
+  // test search on folder with various sorts and max results
+  // see bug #385829 for more details
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bug 385829 test",
+  });
+
+  let now = new Date();
+  // ensure some unique values for date added and last modified
+  // for date added:    b1 < b2 < b3 < b4
+  // for last modified: b1 > b2 > b3 > b4
+  let b1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: "http://a1.com/",
+    title: "1 title",
+    dateAdded: new Date(now.getTime() + 1000),
+  });
+  let b2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: "http://a2.com/",
+    title: "2 title",
+    dateAdded: new Date(now.getTime() + 2000),
+  });
+  let b3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: "http://a3.com/",
+    title: "3 title",
+    dateAdded: new Date(now.getTime() + 3000),
+  });
+  let b4 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: "http://a4.com/",
+    title: "4 title",
+    dateAdded: new Date(now.getTime() + 4000),
+  });
+
+  // make sure lastModified is larger than dateAdded
+  let modifiedTime = new Date(now.getTime() + 5000);
+  await PlacesUtils.bookmarks.update({
+    guid: b1.guid,
+    lastModified: new Date(modifiedTime.getTime() + 4000),
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: b2.guid,
+    lastModified: new Date(modifiedTime.getTime() + 3000),
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: b3.guid,
+    lastModified: new Date(modifiedTime.getTime() + 2000),
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: b4.guid,
+    lastModified: new Date(modifiedTime.getTime() + 1000),
+  });
+
+  let hs = PlacesUtils.history;
+  let options = hs.getNewQueryOptions();
+  let query = hs.getNewQuery();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  options.maxResults = 3;
+  query.setParents([folder.guid]);
+
+  let result = hs.executeQuery(query, options);
+  let rootNode = result.root;
+  rootNode.containerOpen = true;
+
+  // test SORT_BY_DATEADDED_ASCENDING (live update)
+  result.sortingMode = options.SORT_BY_DATEADDED_ASCENDING;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b1.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b3.guid);
+  Assert.ok(rootNode.getChild(0).dateAdded < rootNode.getChild(1).dateAdded);
+  Assert.ok(rootNode.getChild(1).dateAdded < rootNode.getChild(2).dateAdded);
+
+  // test SORT_BY_DATEADDED_DESCENDING (live update)
+  result.sortingMode = options.SORT_BY_DATEADDED_DESCENDING;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b3.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b1.guid);
+  Assert.ok(rootNode.getChild(0).dateAdded > rootNode.getChild(1).dateAdded);
+  Assert.ok(rootNode.getChild(1).dateAdded > rootNode.getChild(2).dateAdded);
+
+  // test SORT_BY_LASTMODIFIED_ASCENDING (live update)
+  result.sortingMode = options.SORT_BY_LASTMODIFIED_ASCENDING;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b3.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b1.guid);
+  Assert.ok(
+    rootNode.getChild(0).lastModified < rootNode.getChild(1).lastModified
+  );
+  Assert.ok(
+    rootNode.getChild(1).lastModified < rootNode.getChild(2).lastModified
+  );
+
+  // test SORT_BY_LASTMODIFIED_DESCENDING (live update)
+  result.sortingMode = options.SORT_BY_LASTMODIFIED_DESCENDING;
+
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b1.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b3.guid);
+  Assert.ok(
+    rootNode.getChild(0).lastModified > rootNode.getChild(1).lastModified
+  );
+  Assert.ok(
+    rootNode.getChild(1).lastModified > rootNode.getChild(2).lastModified
+  );
+  rootNode.containerOpen = false;
+
+  // test SORT_BY_DATEADDED_ASCENDING
+  options.sortingMode = options.SORT_BY_DATEADDED_ASCENDING;
+  result = hs.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b1.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b3.guid);
+  Assert.ok(rootNode.getChild(0).dateAdded < rootNode.getChild(1).dateAdded);
+  Assert.ok(rootNode.getChild(1).dateAdded < rootNode.getChild(2).dateAdded);
+  rootNode.containerOpen = false;
+
+  // test SORT_BY_DATEADDED_DESCENDING
+  options.sortingMode = options.SORT_BY_DATEADDED_DESCENDING;
+  result = hs.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b4.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b3.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b2.guid);
+  Assert.ok(rootNode.getChild(0).dateAdded > rootNode.getChild(1).dateAdded);
+  Assert.ok(rootNode.getChild(1).dateAdded > rootNode.getChild(2).dateAdded);
+  rootNode.containerOpen = false;
+
+  // test SORT_BY_LASTMODIFIED_ASCENDING
+  options.sortingMode = options.SORT_BY_LASTMODIFIED_ASCENDING;
+  result = hs.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b4.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b3.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b2.guid);
+  Assert.ok(
+    rootNode.getChild(0).lastModified < rootNode.getChild(1).lastModified
+  );
+  Assert.ok(
+    rootNode.getChild(1).lastModified < rootNode.getChild(2).lastModified
+  );
+  rootNode.containerOpen = false;
+
+  // test SORT_BY_LASTMODIFIED_DESCENDING
+  options.sortingMode = options.SORT_BY_LASTMODIFIED_DESCENDING;
+  result = hs.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 3);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, b1.guid);
+  Assert.equal(rootNode.getChild(1).bookmarkGuid, b2.guid);
+  Assert.equal(rootNode.getChild(2).bookmarkGuid, b3.guid);
+  Assert.ok(
+    rootNode.getChild(0).lastModified > rootNode.getChild(1).lastModified
+  );
+  Assert.ok(
+    rootNode.getChild(1).lastModified > rootNode.getChild(2).lastModified
+  );
+  rootNode.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_388695.js b/toolkit/components/places/tests/bookmarks/test_388695.js
new file mode 100644
index 0000000000..337d8176bd
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_388695.js
@@ -0,0 +1,45 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get bookmark service
+let bm = PlacesUtils.bookmarks;
+
+// Test that Bookmarks fetch properly orders its results based on
+// the last modified value. Note we cannot rely on dateAdded due to
+// the low PR_Now() resolution.
+
+add_task(async function sort_bookmark_by_relevance() {
+  let now = new Date();
+  let modifiedTime = new Date(now.setHours(now.getHours() - 2));
+
+  let url = "http://foo.tld.com/";
+  let parentGuid = (
+    await bm.insert({
+      type: bm.TYPE_FOLDER,
+      title: "test folder",
+      parentGuid: bm.unfiledGuid,
+    })
+  ).guid;
+  let item1Guid = (await bm.insert({ url, parentGuid })).guid;
+  let item2Guid = (
+    await bm.insert({
+      url,
+      parentGuid,
+      dateAdded: modifiedTime,
+      lastModified: modifiedTime,
+    })
+  ).guid;
+  let bms = [];
+  await bm.fetch({ url }, bm1 => bms.push(bm1));
+  Assert.equal(bms[0].guid, item1Guid);
+  Assert.equal(bms[1].guid, item2Guid);
+  await bm.update({ guid: item2Guid, title: "modified" });
+
+  let bms1 = [];
+  await bm.fetch({ url }, bm2 => bms1.push(bm2));
+  Assert.equal(bms1[0].guid, item2Guid);
+  Assert.equal(bms1[1].guid, item1Guid);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_393498.js b/toolkit/components/places/tests/bookmarks/test_393498.js
new file mode 100644
index 0000000000..bc45066d8b
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_393498.js
@@ -0,0 +1,161 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var observer = {
+  handlePlacesEvents(events) {
+    for (const event of events) {
+      switch (event.type) {
+        case "bookmark-added": {
+          this._itemAddedId = event.id;
+          this._itemAddedParent = event.parentId;
+          this._itemAddedIndex = event.index;
+          break;
+        }
+        case "bookmark-time-changed": {
+          this._itemTimeChangedGuid = event.guid;
+          this._itemTimeChangedDateAdded = event.dateAdded;
+          this._itemTimeChangedLastModified = event.lastModified;
+          break;
+        }
+        case "bookmark-title-changed": {
+          this._itemTitleChangedId = event.id;
+          this._itemTitleChangedTitle = event.title;
+          break;
+        }
+      }
+    }
+  },
+};
+
+observer.handlePlacesEvents = observer.handlePlacesEvents.bind(observer);
+PlacesUtils.observers.addListener(
+  ["bookmark-added", "bookmark-time-changed", "bookmark-title-changed"],
+  observer.handlePlacesEvents
+);
+
+registerCleanupFunction(function () {
+  PlacesUtils.observers.removeListener(
+    ["bookmark-added", "bookmark-time-changed", "bookmark-title-changed"],
+    observer.handlePlacesEvents
+  );
+});
+
+// Returns do_check_eq with .getTime() added onto parameters
+function do_check_date_eq(t1, t2) {
+  return Assert.equal(t1.getTime(), t2.getTime());
+}
+
+add_task(async function test_bookmark_update_notifications() {
+  // We set times in the past to workaround a timing bug due to virtual
+  // machines and the skew between PR_Now() and Date.now(), see bug 427142 and
+  // bug 858377 for details.
+  const PAST_DATE = new Date(Date.now() - 86400000);
+
+  // Insert a new bookmark.
+  let testFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "test Folder",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+  });
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: testFolder.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://google.com/",
+    title: "a bookmark",
+  });
+
+  // Sanity check.
+  Assert.ok(observer.itemChangedProperty === undefined);
+
+  // Set dateAdded in the past and verify the changes.
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    dateAdded: PAST_DATE,
+  });
+
+  Assert.equal(observer._itemTimeChangedGuid, bookmark.guid);
+  Assert.equal(observer._itemTimeChangedDateAdded, PAST_DATE.getTime());
+
+  // After just inserting, modified should be the same as dateAdded.
+  do_check_date_eq(bookmark.lastModified, bookmark.dateAdded);
+
+  let updatedBookmark = await PlacesUtils.bookmarks.fetch({
+    guid: bookmark.guid,
+  });
+
+  do_check_date_eq(updatedBookmark.dateAdded, PAST_DATE);
+
+  // Set lastModified in the past and verify the changes.
+  updatedBookmark = await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    lastModified: PAST_DATE,
+  });
+
+  Assert.equal(observer._itemTimeChangedGuid, bookmark.guid);
+  Assert.equal(observer._itemTimeChangedLastModified, PAST_DATE.getTime());
+  do_check_date_eq(updatedBookmark.lastModified, PAST_DATE);
+
+  // Set bookmark title
+  updatedBookmark = await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    title: "Google",
+  });
+
+  // Test notifications.
+  Assert.equal(
+    observer._itemTitleChangedId,
+    await PlacesTestUtils.promiseItemId(bookmark.guid)
+  );
+  Assert.equal(observer._itemTitleChangedTitle, "Google");
+
+  // Check lastModified has been updated.
+  Assert.ok(is_time_ordered(PAST_DATE, updatedBookmark.lastModified.getTime()));
+
+  // Check that node properties are updated.
+  let root = PlacesUtils.getFolderContents(testFolder.guid).root;
+  Assert.equal(root.childCount, 1);
+  let childNode = root.getChild(0);
+
+  // confirm current dates match node properties
+  Assert.equal(
+    PlacesUtils.toPRTime(updatedBookmark.dateAdded),
+    childNode.dateAdded
+  );
+  Assert.equal(
+    PlacesUtils.toPRTime(updatedBookmark.lastModified),
+    childNode.lastModified
+  );
+
+  // Test live update of lastModified when setting title.
+  updatedBookmark = await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    lastModified: PAST_DATE,
+    title: "Google",
+  });
+
+  // Check lastModified has been updated.
+  Assert.ok(is_time_ordered(PAST_DATE, childNode.lastModified));
+  // Test that node value matches db value.
+  Assert.equal(
+    PlacesUtils.toPRTime(updatedBookmark.lastModified),
+    childNode.lastModified
+  );
+
+  // Test live update of the exposed date apis.
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    dateAdded: PAST_DATE,
+  });
+  Assert.equal(childNode.dateAdded, PlacesUtils.toPRTime(PAST_DATE));
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    lastModified: PAST_DATE,
+  });
+  Assert.equal(childNode.lastModified, PlacesUtils.toPRTime(PAST_DATE));
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_405938_restore_queries.js b/toolkit/components/places/tests/bookmarks/test_405938_restore_queries.js
new file mode 100644
index 0000000000..c893f1db3f
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_405938_restore_queries.js
@@ -0,0 +1,253 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var tests = [];
+
+/*
+
+Backup/restore tests example:
+
+var myTest = {
+  populate: function () { ... add bookmarks ... },
+  validate: function () { ... query for your bookmarks ... }
+}
+
+this.push(myTest);
+
+*/
+
+/*
+
+test summary:
+- create folders with content
+- create a query bookmark for those folders
+- backs up bookmarks
+- restores bookmarks
+- confirms that the query has the new ids for the same folders
+
+scenarios:
+- 1 folder  (folder shortcut)
+- n folders (single query)
+- n folders (multiple queries)
+
+*/
+
+var test = {
+  _testRootId: null,
+  _testRootTitle: "test root",
+  _folderGuids: [],
+  _bookmarkURIs: [],
+  _count: 3,
+  _extraBookmarksCount: 10,
+
+  populate: async function populate() {
+    // folder to hold this test
+    await PlacesUtils.bookmarks.eraseEverything();
+
+    let testFolderItems = [];
+    // Set a date 60 seconds ago, so that we can set newer bookmarks later.
+    let dateAdded = new Date(new Date() - 60000);
+
+    // create test folders each with a bookmark
+    for (let i = 0; i < this._count; i++) {
+      this._folderGuids.push(PlacesUtils.history.makeGuid());
+      testFolderItems.push({
+        guid: this._folderGuids[i],
+        title: `folder${i}`,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        dateAdded,
+        children: [
+          {
+            dateAdded,
+            url: `http://${i}`,
+            title: `bookmark${i}`,
+          },
+        ],
+      });
+    }
+
+    let bookmarksTree = {
+      guid: PlacesUtils.bookmarks.toolbarGuid,
+      children: [
+        {
+          dateAdded,
+          title: this._testRootTitle,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          children: testFolderItems,
+        },
+      ],
+    };
+
+    let insertedBookmarks = await PlacesUtils.bookmarks.insertTree(
+      bookmarksTree
+    );
+
+    // create a query URI with 1 folder (ie: folder shortcut)
+    this._queryURI1 = `place:parent=${this._folderGuids[0]}&queryType=1`;
+    this._queryTitle1 = "query1";
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: insertedBookmarks[0].guid,
+      dateAdded,
+      url: this._queryURI1,
+      title: this._queryTitle1,
+    });
+
+    // create a query URI with _count folders
+    this._queryURI2 = `place:parent=${this._folderGuids.join(
+      "&parent="
+    )}&queryType=1`;
+    this._queryTitle2 = "query2";
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: insertedBookmarks[0].guid,
+      dateAdded,
+      url: this._queryURI2,
+      title: this._queryTitle2,
+    });
+
+    // Create a query URI for most recent bookmarks with NO folders specified.
+    this._queryURI3 =
+      "place:queryType=1&sort=12&maxResults=10&excludeQueries=1";
+    this._queryTitle3 = "query3";
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: insertedBookmarks[0].guid,
+      dateAdded,
+      url: this._queryURI3,
+      title: this._queryTitle3,
+    });
+  },
+
+  clean() {},
+
+  validate: async function validate(addExtras) {
+    if (addExtras) {
+      // Throw a wrench in the works by inserting some new bookmarks,
+      // ensuring folder ids won't be the same, when restoring.
+      let date = new Date() - this._extraBookmarksCount * 1000;
+      for (let i = 0; i < this._extraBookmarksCount; i++) {
+        await PlacesUtils.bookmarks.insert({
+          parentGuid: PlacesUtils.bookmarks.menuGuid,
+          url: uri("http://aaaa" + i),
+          dateAdded: new Date(date + (this._extraBookmarksCount - i) * 1000),
+        });
+      }
+    }
+
+    var toolbar = PlacesUtils.getFolderContents(
+      PlacesUtils.bookmarks.toolbarGuid,
+      false,
+      true
+    ).root;
+    Assert.equal(toolbar.childCount, 1);
+
+    var folderNode = toolbar.getChild(0);
+    Assert.equal(folderNode.type, folderNode.RESULT_TYPE_FOLDER);
+    Assert.equal(folderNode.title, this._testRootTitle);
+    folderNode.QueryInterface(Ci.nsINavHistoryQueryResultNode);
+    folderNode.containerOpen = true;
+
+    // |_count| folders + the query nodes
+    Assert.equal(folderNode.childCount, this._count + 3);
+
+    for (let i = 0; i < this._count; i++) {
+      var subFolder = folderNode.getChild(i);
+      Assert.equal(subFolder.title, "folder" + i);
+      subFolder.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+      subFolder.containerOpen = true;
+      Assert.equal(subFolder.childCount, 1);
+      var child = subFolder.getChild(0);
+      Assert.equal(child.title, "bookmark" + i);
+      Assert.ok(uri(child.uri).equals(uri("http://" + i)));
+    }
+
+    // validate folder shortcut
+    this.validateQueryNode1(folderNode.getChild(this._count));
+
+    // validate folders query
+    this.validateQueryNode2(folderNode.getChild(this._count + 1));
+
+    // validate recent folders query
+    this.validateQueryNode3(folderNode.getChild(this._count + 2));
+
+    // clean up
+    folderNode.containerOpen = false;
+    toolbar.containerOpen = false;
+  },
+
+  validateQueryNode1: function validateQueryNode1(aNode) {
+    Assert.equal(aNode.title, this._queryTitle1);
+    Assert.ok(PlacesUtils.nodeIsFolder(aNode));
+
+    aNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    aNode.containerOpen = true;
+    Assert.equal(aNode.childCount, 1);
+    var child = aNode.getChild(0);
+    Assert.ok(uri(child.uri).equals(uri("http://0")));
+    Assert.equal(child.title, "bookmark0");
+    aNode.containerOpen = false;
+  },
+
+  validateQueryNode2: function validateQueryNode2(aNode) {
+    Assert.equal(aNode.title, this._queryTitle2);
+    Assert.ok(PlacesUtils.nodeIsQuery(aNode));
+
+    aNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    aNode.containerOpen = true;
+    Assert.equal(aNode.childCount, this._count);
+    for (var i = 0; i < aNode.childCount; i++) {
+      var child = aNode.getChild(i);
+      Assert.ok(uri(child.uri).equals(uri("http://" + i)));
+      Assert.equal(child.title, "bookmark" + i);
+    }
+    aNode.containerOpen = false;
+  },
+
+  validateQueryNode3(aNode) {
+    Assert.equal(aNode.title, this._queryTitle3);
+    Assert.ok(PlacesUtils.nodeIsQuery(aNode));
+
+    aNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    aNode.containerOpen = true;
+    // The query will list the extra bookmarks added at the start of validate.
+    Assert.equal(aNode.childCount, this._extraBookmarksCount);
+    for (var i = 0; i < aNode.childCount; i++) {
+      var child = aNode.getChild(i);
+      Assert.equal(child.uri, `http://aaaa${i}/`);
+    }
+    aNode.containerOpen = false;
+  },
+};
+tests.push(test);
+
+add_task(async function () {
+  // make json file
+  let jsonFile = PathUtils.join(PathUtils.profileDir, "bookmarks.json");
+
+  // populate db
+  for (let singleTest of tests) {
+    await singleTest.populate();
+    // sanity
+    await singleTest.validate(true);
+  }
+
+  // export json to file
+  await BookmarkJSONUtils.exportToFile(jsonFile);
+
+  // clean
+  for (let singleTest of tests) {
+    singleTest.clean();
+  }
+
+  // restore json file
+  await BookmarkJSONUtils.importFromFile(jsonFile, { replace: true });
+
+  // validate
+  for (let singleTest of tests) {
+    await singleTest.validate(false);
+  }
+
+  // clean up
+  await IOUtils.remove(jsonFile);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_424958-json-quoted-folders.js b/toolkit/components/places/tests/bookmarks/test_424958-json-quoted-folders.js
new file mode 100644
index 0000000000..2a7ce3f003
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_424958-json-quoted-folders.js
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const FOLDER_TITLE = '"quoted folder"';
+
+function checkQuotedFolder() {
+  let toolbar = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  ).root;
+
+  // test for our quoted folder
+  Assert.equal(toolbar.childCount, 1);
+  var folderNode = toolbar.getChild(0);
+  Assert.equal(folderNode.type, folderNode.RESULT_TYPE_FOLDER);
+  Assert.equal(folderNode.title, FOLDER_TITLE);
+
+  // clean up
+  toolbar.containerOpen = false;
+}
+
+add_task(async function () {
+  // make json file
+  let jsonFile = PathUtils.join(PathUtils.profileDir, "bookmarks.json");
+
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: FOLDER_TITLE,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  checkQuotedFolder();
+
+  // export json to file
+  await BookmarkJSONUtils.exportToFile(jsonFile);
+
+  await PlacesUtils.bookmarks.remove(folder.guid);
+
+  // restore json file
+  await BookmarkJSONUtils.importFromFile(jsonFile, { replace: true });
+
+  checkQuotedFolder();
+
+  // clean up
+  await IOUtils.remove(jsonFile);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_448584.js b/toolkit/components/places/tests/bookmarks/test_448584.js
new file mode 100644
index 0000000000..07665327b1
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_448584.js
@@ -0,0 +1,90 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get database connection
+try {
+  var mDBConn = PlacesUtils.history.DBConnection;
+} catch (ex) {
+  do_throw("Could not get database connection\n");
+}
+
+/*
+  This test is:
+    - don't try to add invalid uri nodes to a JSON backup
+*/
+
+const ITEM_TITLE = "invalid uri";
+const ITEM_URL = "http://test.mozilla.org";
+
+function validateResults(expectedValidItemsCount) {
+  var query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = PlacesUtils.history.getNewQueryOptions();
+  var result = PlacesUtils.history.executeQuery(query, options);
+
+  var toolbar = result.root;
+  toolbar.containerOpen = true;
+
+  // test for our bookmark
+  Assert.equal(toolbar.childCount, expectedValidItemsCount);
+  for (var i = 0; i < toolbar.childCount; i++) {
+    var folderNode = toolbar.getChild(0);
+    Assert.equal(folderNode.type, folderNode.RESULT_TYPE_URI);
+    Assert.equal(folderNode.title, ITEM_TITLE);
+  }
+
+  // clean up
+  toolbar.containerOpen = false;
+}
+
+add_task(async function () {
+  // make json file
+  let jsonFile = PathUtils.join(PathUtils.profileDir, "bookmarks.json");
+
+  // populate db
+  // add a valid bookmark
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: ITEM_TITLE,
+    url: ITEM_URL,
+  });
+
+  let badBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: ITEM_TITLE,
+    url: ITEM_URL,
+  });
+  // sanity
+  validateResults(2);
+  // Something in the code went wrong and we finish up losing the place, so
+  // the bookmark uri becomes null.
+  var sql = "UPDATE moz_bookmarks SET fk = 1337 WHERE guid = ?1";
+  var stmt = mDBConn.createStatement(sql);
+  stmt.bindByIndex(0, badBookmark.guid);
+  try {
+    stmt.execute();
+  } finally {
+    stmt.finalize();
+  }
+
+  await BookmarkJSONUtils.exportToFile(jsonFile);
+
+  // clean
+  await PlacesUtils.bookmarks.remove(badBookmark);
+
+  // restore json file
+  try {
+    await BookmarkJSONUtils.importFromFile(jsonFile, { replace: true });
+  } catch (ex) {
+    do_throw("couldn't import the exported file: " + ex);
+  }
+
+  // validate
+  validateResults(1);
+
+  // clean up
+  await IOUtils.remove(jsonFile);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_458683.js b/toolkit/components/places/tests/bookmarks/test_458683.js
new file mode 100644
index 0000000000..d31fca66e1
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_458683.js
@@ -0,0 +1,111 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+  This test is:
+    - don't block while doing backup and restore if tag containers contain
+      bogus items (separators, folders)
+*/
+
+const ITEM_TITLE = "invalid uri";
+const ITEM_URL = "http://test.mozilla.org/";
+const TAG_NAME = "testTag";
+
+function validateResults() {
+  let toolbar = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  ).root;
+  // test for our bookmark
+  Assert.equal(toolbar.childCount, 1);
+  for (var i = 0; i < toolbar.childCount; i++) {
+    var folderNode = toolbar.getChild(0);
+    Assert.equal(folderNode.type, folderNode.RESULT_TYPE_URI);
+    Assert.equal(folderNode.title, ITEM_TITLE);
+  }
+  toolbar.containerOpen = false;
+
+  // test for our tag
+  var tags = PlacesUtils.tagging.getTagsForURI(Services.io.newURI(ITEM_URL));
+  Assert.equal(tags.length, 1);
+  Assert.equal(tags[0], TAG_NAME);
+}
+
+add_task(async function () {
+  let jsonFile = PathUtils.join(PathUtils.profileDir, "bookmarks.json");
+
+  // add a valid bookmark
+  let item = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: ITEM_TITLE,
+    url: ITEM_URL,
+  });
+
+  // create a tag
+  PlacesUtils.tagging.tagURI(Services.io.newURI(ITEM_URL), [TAG_NAME]);
+  // get tag folder id
+  let tagRoot = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.tagsGuid
+  ).root;
+  Assert.equal(tagRoot.childCount, 1);
+  let tagItemGuid = PlacesUtils.asContainer(tagRoot.getChild(0)).bookmarkGuid;
+  tagRoot.containerOpen = false;
+
+  function insert({ type, parentGuid }) {
+    return PlacesUtils.withConnectionWrapper(
+      "test_458683: insert",
+      async db => {
+        await db.executeCached(
+          `INSERT INTO moz_bookmarks (type, parent, position, guid)
+         VALUES (:type,
+                 (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+                 (SELECT MAX(position) + 1 FROM moz_bookmarks WHERE parent = (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid)),
+                 GENERATE_GUID())`,
+          { type, parentGuid }
+        );
+      }
+    );
+  }
+
+  // add a separator and a folder inside tag folder
+  // We must insert these manually, because the new bookmarking API doesn't
+  // support inserting invalid items into the tag folder.
+  await insert({
+    parentGuid: tagItemGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  await insert({
+    parentGuid: tagItemGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  // add a separator and a folder inside tag root
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "test tags root folder",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  // sanity
+  validateResults();
+
+  await BookmarkJSONUtils.exportToFile(jsonFile);
+
+  // clean
+  PlacesUtils.tagging.untagURI(Services.io.newURI(ITEM_URL), [TAG_NAME]);
+  await PlacesUtils.bookmarks.remove(item);
+
+  // restore json file
+  await BookmarkJSONUtils.importFromFile(jsonFile, { replace: true });
+
+  validateResults();
+
+  // clean up
+  await IOUtils.remove(jsonFile);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_466303-json-remove-backups.js b/toolkit/components/places/tests/bookmarks/test_466303-json-remove-backups.js
new file mode 100644
index 0000000000..4596ed93b2
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_466303-json-remove-backups.js
@@ -0,0 +1,86 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Since PlacesBackups.getbackupFiles() is a lazy getter, these tests must
+// run in the given order, to avoid making it out-of-sync.
+
+async function countChildren(path) {
+  let children = await IOUtils.getChildren(path);
+  let count = 0;
+  let lastBackupPath = null;
+  for (let entry of children) {
+    count++;
+    if (PlacesBackups.filenamesRegex.test(PathUtils.filename(entry))) {
+      lastBackupPath = entry;
+    }
+  }
+  return { count, lastBackupPath };
+}
+
+add_task(async function check_max_backups_is_respected() {
+  // Get bookmarkBackups directory
+  let backupFolder = await PlacesBackups.getBackupFolder();
+
+  // Create 2 json dummy backups in the past.
+  let oldJsonPath = PathUtils.join(backupFolder, "bookmarks-2008-01-01.json");
+  await IOUtils.writeUTF8(oldJsonPath, "");
+  Assert.ok(await IOUtils.exists(oldJsonPath));
+
+  let jsonPath = PathUtils.join(backupFolder, "bookmarks-2008-01-31.json");
+  await IOUtils.writeUTF8(jsonPath, "");
+  Assert.ok(await IOUtils.exists(jsonPath));
+
+  // Export bookmarks to JSON.
+  // Allow 2 backups, the older one should be removed.
+  await PlacesBackups.create(2);
+
+  let { count, lastBackupPath } = await countChildren(backupFolder);
+  Assert.equal(count, 2);
+  Assert.notEqual(lastBackupPath, null);
+  Assert.equal(false, await IOUtils.exists(oldJsonPath));
+  Assert.ok(await IOUtils.exists(jsonPath));
+});
+
+add_task(async function check_max_backups_greater_than_backups() {
+  // Get bookmarkBackups directory
+  let backupFolder = await PlacesBackups.getBackupFolder();
+
+  // Export bookmarks to JSON.
+  // Allow 3 backups, none should be removed.
+  await PlacesBackups.create(3);
+
+  let { count, lastBackupPath } = await countChildren(backupFolder);
+  Assert.equal(count, 2);
+  Assert.notEqual(lastBackupPath, null);
+});
+
+add_task(async function check_max_backups_null() {
+  // Get bookmarkBackups directory
+  let backupFolder = await PlacesBackups.getBackupFolder();
+
+  // Export bookmarks to JSON.
+  // Allow infinite backups, none should be removed, a new one is not created
+  // since one for today already exists.
+  await PlacesBackups.create(null);
+
+  let { count, lastBackupPath } = await countChildren(backupFolder);
+  Assert.equal(count, 2);
+  Assert.notEqual(lastBackupPath, null);
+});
+
+add_task(async function check_max_backups_undefined() {
+  // Get bookmarkBackups directory
+  let backupFolder = await PlacesBackups.getBackupFolder();
+
+  // Export bookmarks to JSON.
+  // Allow infinite backups, none should be removed, a new one is not created
+  // since one for today already exists.
+  await PlacesBackups.create();
+
+  let { count, lastBackupPath } = await countChildren(backupFolder);
+  Assert.equal(count, 2);
+  Assert.notEqual(lastBackupPath, null);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_477583_json-backup-in-future.js b/toolkit/components/places/tests/bookmarks/test_477583_json-backup-in-future.js
new file mode 100644
index 0000000000..ab4f4a02d5
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_477583_json-backup-in-future.js
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+add_task(async function test_json_backup_in_future() {
+  let backupFolder = await PlacesBackups.getBackupFolder();
+  let bookmarksBackupDir = new FileUtils.File(backupFolder);
+  // Remove all files from backups folder.
+  let files = bookmarksBackupDir.directoryEntries;
+  while (files.hasMoreElements()) {
+    let entry = files.nextFile;
+    entry.remove(false);
+  }
+
+  // Create a json dummy backup in the future.
+  let dateObj = new Date();
+  dateObj.setYear(dateObj.getFullYear() + 1);
+  let name = PlacesBackups.getFilenameForDate(dateObj);
+  Assert.equal(
+    name,
+    "bookmarks-" + PlacesBackups.toISODateString(dateObj) + ".json"
+  );
+  files = bookmarksBackupDir.directoryEntries;
+  while (files.hasMoreElements()) {
+    let entry = files.nextFile;
+    if (PlacesBackups.filenamesRegex.test(entry.leafName)) {
+      entry.remove(false);
+    }
+  }
+
+  let futureBackupFile = bookmarksBackupDir.clone();
+  futureBackupFile.append(name);
+  futureBackupFile.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+  Assert.ok(futureBackupFile.exists());
+
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 0);
+
+  await PlacesBackups.create();
+  // Check that a backup for today has been created.
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 1);
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+  Assert.notEqual(mostRecentBackupFile, null);
+  Assert.ok(
+    PlacesBackups.filenamesRegex.test(PathUtils.filename(mostRecentBackupFile))
+  );
+
+  // Check that future backup has been removed.
+  Assert.ok(!futureBackupFile.exists());
+
+  // Cleanup.
+  mostRecentBackupFile = new FileUtils.File(mostRecentBackupFile);
+  mostRecentBackupFile.remove(false);
+  Assert.ok(!mostRecentBackupFile.exists());
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_818584-discard-duplicate-backups.js b/toolkit/components/places/tests/bookmarks/test_818584-discard-duplicate-backups.js
new file mode 100644
index 0000000000..be5d53f8c6
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_818584-discard-duplicate-backups.js
@@ -0,0 +1,66 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Checks that automatically created bookmark backups are discarded if they are
+ * duplicate of an existing ones.
+ */
+add_task(async function () {
+  // Create a backup for yesterday in the backups folder.
+  let backupFolder = await PlacesBackups.getBackupFolder();
+  let dateObj = new Date();
+  dateObj.setDate(dateObj.getDate() - 1);
+  let oldBackupName = PlacesBackups.getFilenameForDate(dateObj);
+  let oldBackup = PathUtils.join(backupFolder, oldBackupName);
+  let { count: count, hash: hash } = await BookmarkJSONUtils.exportToFile(
+    oldBackup
+  );
+  Assert.ok(count > 0);
+  Assert.equal(hash.length, 24);
+  oldBackupName = oldBackupName.replace(
+    /\.json/,
+    "_" + count + "_" + hash + ".json"
+  );
+  await IOUtils.move(oldBackup, PathUtils.join(backupFolder, oldBackupName));
+
+  // Create a backup.
+  // This should just rename the existing backup, so in the end there should be
+  // only one backup with today's date.
+  await PlacesBackups.create();
+
+  // Get the hash of the generated backup
+  let backupFiles = await PlacesBackups.getBackupFiles();
+  Assert.equal(backupFiles.length, 1);
+
+  let matches = PathUtils.filename(backupFiles[0]).match(
+    PlacesBackups.filenamesRegex
+  );
+  Assert.equal(matches[1], PlacesBackups.toISODateString(new Date()));
+  Assert.equal(matches[2], count);
+  Assert.equal(matches[3], hash);
+
+  // Add a bookmark and create another backup.
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "foo",
+    url: "http://foo.com",
+  });
+
+  // We must enforce a backup since one for today already exists.  The forced
+  // backup will replace the existing one.
+  await PlacesBackups.create(undefined, true);
+  Assert.equal(backupFiles.length, 1);
+  let recentBackup = await PlacesBackups.getMostRecentBackup();
+  Assert.notEqual(recentBackup, PathUtils.join(backupFolder, oldBackupName));
+  matches = PathUtils.filename(recentBackup).match(
+    PlacesBackups.filenamesRegex
+  );
+  Assert.equal(matches[1], PlacesBackups.toISODateString(new Date()));
+  Assert.equal(matches[2], count + 1);
+  Assert.notEqual(matches[3], hash);
+
+  // Clean up
+  await PlacesUtils.bookmarks.remove(bookmark);
+  await PlacesBackups.create(0);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_818587_compress-bookmarks-backups.js b/toolkit/components/places/tests/bookmarks/test_818587_compress-bookmarks-backups.js
new file mode 100644
index 0000000000..91e0c50f7e
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_818587_compress-bookmarks-backups.js
@@ -0,0 +1,61 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function compress_bookmark_backups_test() {
+  // Check for jsonlz4 extension
+  let todayFilename = PlacesBackups.getFilenameForDate(
+    new Date(2014, 4, 15),
+    true
+  );
+  Assert.equal(todayFilename, "bookmarks-2014-05-15.jsonlz4");
+
+  await PlacesBackups.create();
+
+  // Check that a backup for today has been created and the regex works fine for lz4.
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 1);
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+  Assert.notEqual(mostRecentBackupFile, null);
+  Assert.ok(
+    PlacesBackups.filenamesRegex.test(PathUtils.filename(mostRecentBackupFile))
+  );
+
+  // The most recent backup file has to be removed since saveBookmarksToJSONFile
+  // will otherwise over-write the current backup, since it will be made on the
+  // same date
+  await IOUtils.remove(mostRecentBackupFile);
+  Assert.equal(false, await IOUtils.exists(mostRecentBackupFile));
+
+  // Check that, if the user created a custom backup out of the default
+  // backups folder, it gets copied (compressed) into it.
+  let jsonFile = PathUtils.join(PathUtils.profileDir, "bookmarks.json");
+  await PlacesBackups.saveBookmarksToJSONFile(jsonFile);
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 1);
+
+  // Check if import works from lz4 compressed json
+  let url = "http://www.mozilla.org/en-US/";
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark",
+    url,
+  });
+
+  // Force create a compressed backup, Remove the bookmark, the restore the backup
+  await PlacesBackups.create(undefined, true);
+  let recentBackup = await PlacesBackups.getMostRecentBackup();
+  await PlacesUtils.bookmarks.remove(bm);
+  await BookmarkJSONUtils.importFromFile(recentBackup, { replace: true });
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let node = root.getChild(0);
+  Assert.equal(node.uri, url);
+
+  root.containerOpen = false;
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Cleanup.
+  await IOUtils.remove(jsonFile);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_818593-store-backup-metadata.js b/toolkit/components/places/tests/bookmarks/test_818593-store-backup-metadata.js
new file mode 100644
index 0000000000..6d280e8cad
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_818593-store-backup-metadata.js
@@ -0,0 +1,53 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * To confirm that metadata i.e. bookmark count is set and retrieved for
+ * automatic backups.
+ */
+add_task(async function test_saveBookmarksToJSONFile_and_create() {
+  // Add a bookmark
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "Get Firefox!",
+    url: "http://getfirefox.com/",
+  });
+
+  // Test saveBookmarksToJSONFile()
+  let backupFile = PathUtils.join(PathUtils.tempDir, "bookmarks.json");
+
+  let nodeCount = await PlacesBackups.saveBookmarksToJSONFile(backupFile, true);
+  Assert.ok(nodeCount > 0);
+  Assert.ok(await IOUtils.exists(backupFile));
+
+  // Ensure the backup would be copied to our backups folder when the original
+  // backup is saved somewhere else.
+  let recentBackup = await PlacesBackups.getMostRecentBackup();
+  let matches = PathUtils.filename(recentBackup).match(
+    PlacesBackups.filenamesRegex
+  );
+  Assert.equal(matches[2], nodeCount);
+  Assert.equal(matches[3].length, 24);
+
+  // Clear all backups in our backups folder.
+  await PlacesBackups.create(0);
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 0);
+
+  // Test create() which saves bookmarks with metadata on the filename.
+  await PlacesBackups.create();
+  Assert.equal((await PlacesBackups.getBackupFiles()).length, 1);
+
+  let mostRecentBackupFile = await PlacesBackups.getMostRecentBackup();
+  Assert.notEqual(mostRecentBackupFile, null);
+  matches = PathUtils.filename(recentBackup).match(
+    PlacesBackups.filenamesRegex
+  );
+  Assert.equal(matches[2], nodeCount);
+  Assert.equal(matches[3].length, 24);
+
+  // Cleanup
+  await IOUtils.remove(backupFile);
+  await PlacesBackups.create(0);
+  await PlacesUtils.bookmarks.remove(bookmark);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_992901-backup-unsorted-hierarchy.js b/toolkit/components/places/tests/bookmarks/test_992901-backup-unsorted-hierarchy.js
new file mode 100644
index 0000000000..c835a3bd09
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_992901-backup-unsorted-hierarchy.js
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Checks that backups properly include all of the bookmarks if the hierarchy
+ * in the database is unordered so that a hierarchy is defined before its
+ * ancestor in the bookmarks table.
+ */
+add_task(async function () {
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "bookmark",
+        url: "http://mozilla.org",
+      },
+      {
+        title: "f2",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      },
+      {
+        title: "f1",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      },
+    ],
+  });
+
+  let bookmark = bms[0];
+  let folder2 = bms[1];
+  let folder1 = bms[2];
+  bookmark.parentGuid = folder2.guid;
+  await PlacesUtils.bookmarks.update(bookmark);
+
+  folder2.parentGuid = folder1.guid;
+  await PlacesUtils.bookmarks.update(folder2);
+
+  // Create a backup.
+  await PlacesBackups.create();
+
+  // Remove the bookmarks, then restore the backup.
+  await PlacesUtils.bookmarks.remove(folder1);
+  await BookmarkJSONUtils.importFromFile(
+    await PlacesBackups.getMostRecentBackup(),
+    { replace: true }
+  );
+
+  info("Checking first level");
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let level1 = root.getChild(0);
+  Assert.equal(level1.title, "f1");
+  info("Checking second level");
+  PlacesUtils.asContainer(level1).containerOpen = true;
+  let level2 = level1.getChild(0);
+  Assert.equal(level2.title, "f2");
+  info("Checking bookmark");
+  PlacesUtils.asContainer(level2).containerOpen = true;
+  bookmark = level2.getChild(0);
+  Assert.equal(bookmark.title, "bookmark");
+  level2.containerOpen = false;
+  level1.containerOpen = false;
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_997030-bookmarks-html-encode.js b/toolkit/components/places/tests/bookmarks/test_997030-bookmarks-html-encode.js
new file mode 100644
index 0000000000..6f3132b275
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_997030-bookmarks-html-encode.js
@@ -0,0 +1,37 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Checks that we don't encodeURI twice when creating bookmarks.html.
+ */
+add_task(async function () {
+  let url =
+    "http://bt.ktxp.com/search.php?keyword=%E5%A6%84%E6%83%B3%E5%AD%A6%E7%94%9F%E4%BC%9A";
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark",
+    url,
+  });
+
+  let file = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.997030.html"
+  );
+  await IOUtils.remove(file, { ignoreAbsent: true });
+  await BookmarkHTMLUtils.exportToFile(file);
+
+  // Remove the bookmarks, then restore the backup.
+  await PlacesUtils.bookmarks.remove(bm);
+  await BookmarkHTMLUtils.importFromFile(file, { replace: true });
+
+  info("Checking first level");
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let node = root.getChild(0);
+  Assert.equal(node.uri, url);
+
+  root.containerOpen = false;
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_async_observers.js b/toolkit/components/places/tests/bookmarks/test_async_observers.js
new file mode 100644
index 0000000000..504f489339
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_async_observers.js
@@ -0,0 +1,71 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* This test checks that bookmarks service is correctly forwarding async
+ * events like visit or favicon additions. */
+
+let gBookmarkGuids = [];
+
+add_task(async function setup() {
+  // Add multiple bookmarks to the same uri.
+  gBookmarkGuids.push(
+    (
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: "http://book.ma.rk/",
+      })
+    ).guid
+  );
+  gBookmarkGuids.push(
+    (
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        url: "http://book.ma.rk/",
+      })
+    ).guid
+  );
+  Assert.equal(gBookmarkGuids.length, 2);
+});
+
+add_task(async function test_add_icon() {
+  // Add a visit to the bookmark and wait for the observer.
+  let guids = new Set(gBookmarkGuids);
+  Assert.equal(guids.size, 2);
+  let promiseNotifications = PlacesTestUtils.waitForNotification(
+    "favicon-changed",
+    events =>
+      events.some(
+        event =>
+          event.url == "http://book.ma.rk/" &&
+          event.faviconUrl.startsWith("data:image/png;base64")
+      )
+  );
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    NetUtil.newURI("http://book.ma.rk/"),
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  await promiseNotifications;
+});
+
+add_task(async function test_remove_page() {
+  // Add a visit to the bookmark and wait for the observer.
+  let guids = new Set(gBookmarkGuids);
+  Assert.equal(guids.size, 2);
+  let promiseNotifications = PlacesTestUtils.waitForNotification(
+    "page-removed",
+    events =>
+      events.some(
+        event =>
+          event.url === "http://book.ma.rk/" &&
+          !event.isRemovedFromStore &&
+          !event.isPartialVisistsRemoval
+      )
+  );
+  await PlacesUtils.history.remove("http://book.ma.rk/");
+  await promiseNotifications;
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bmindex.js b/toolkit/components/places/tests/bookmarks/test_bmindex.js
new file mode 100644
index 0000000000..c79da88282
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bmindex.js
@@ -0,0 +1,133 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const NUM_BOOKMARKS = 20;
+const NUM_SEPARATORS = 5;
+const NUM_FOLDERS = 10;
+const NUM_ITEMS = NUM_BOOKMARKS + NUM_SEPARATORS + NUM_FOLDERS;
+const MIN_RAND = -5;
+const MAX_RAND = 40;
+
+async function check_contiguous_indexes(bookmarks) {
+  var indexes = [];
+  for (let bm of bookmarks) {
+    let bmIndex = (await PlacesUtils.bookmarks.fetch(bm.guid)).index;
+    info(`Index: ${bmIndex}\n`);
+    info("Checking duplicates\n");
+    Assert.ok(!indexes.includes(bmIndex));
+    info(`Checking out of range, found ${bookmarks.length} items\n`);
+    Assert.ok(bmIndex >= 0 && bmIndex < bookmarks.length);
+    indexes.push(bmIndex);
+  }
+  info("Checking all valid indexes have been used\n");
+  Assert.equal(indexes.length, bookmarks.length);
+}
+
+add_task(async function test_bookmarks_indexing() {
+  let bookmarks = [];
+  // Insert bookmarks with random indexes.
+  for (let i = 0; bookmarks.length < NUM_BOOKMARKS; i++) {
+    let randIndex = Math.round(
+      MIN_RAND + Math.random() * (MAX_RAND - MIN_RAND)
+    );
+    try {
+      let bm = await PlacesUtils.bookmarks.insert({
+        index: randIndex,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: `Test bookmark ${i}`,
+        url: `http://${i}.mozilla.org/`,
+      });
+      if (randIndex < -1) {
+        do_throw("Creating a bookmark at an invalid index should throw");
+      }
+      bookmarks.push(bm);
+    } catch (ex) {
+      if (randIndex >= -1) {
+        do_throw("Creating a bookmark at a valid index should not throw");
+      }
+    }
+  }
+  await check_contiguous_indexes(bookmarks);
+
+  // Insert separators with random indexes.
+  for (let i = 0; bookmarks.length < NUM_BOOKMARKS + NUM_SEPARATORS; i++) {
+    let randIndex = Math.round(
+      MIN_RAND + Math.random() * (MAX_RAND - MIN_RAND)
+    );
+    try {
+      let bm = await PlacesUtils.bookmarks.insert({
+        index: randIndex,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      });
+      if (randIndex < -1) {
+        do_throw("Creating a separator at an invalid index should throw");
+      }
+      bookmarks.push(bm);
+    } catch (ex) {
+      if (randIndex >= -1) {
+        do_throw("Creating a separator at a valid index should not throw");
+      }
+    }
+  }
+  await check_contiguous_indexes(bookmarks);
+
+  // Insert folders with random indexes.
+  for (let i = 0; bookmarks.length < NUM_ITEMS; i++) {
+    let randIndex = Math.round(
+      MIN_RAND + Math.random() * (MAX_RAND - MIN_RAND)
+    );
+    try {
+      let bm = await PlacesUtils.bookmarks.insert({
+        index: randIndex,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: `Test folder ${i}`,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      });
+      if (randIndex < -1) {
+        do_throw("Creating a folder at an invalid index should throw");
+      }
+      bookmarks.push(bm);
+    } catch (ex) {
+      if (randIndex >= -1) {
+        do_throw("Creating a folder at a valid index should not throw");
+      }
+    }
+  }
+  await check_contiguous_indexes(bookmarks);
+
+  // Execute some random bookmark delete.
+  for (let i = 0; i < Math.ceil(NUM_ITEMS / 4); i++) {
+    let bm = bookmarks.splice(
+      Math.floor(Math.random() * bookmarks.length),
+      1
+    )[0];
+    info(`Removing item with guid ${bm.guid}\n`);
+    await PlacesUtils.bookmarks.remove(bm);
+  }
+  await check_contiguous_indexes(bookmarks);
+
+  // Execute some random bookmark move.  This will also try to move it to
+  // invalid index values.
+  for (let i = 0; i < Math.ceil(NUM_ITEMS / 4); i++) {
+    let randIndex = Math.floor(Math.random() * bookmarks.length);
+    let bm = bookmarks[randIndex];
+    let newIndex = Math.round(MIN_RAND + Math.random() * (MAX_RAND - MIN_RAND));
+    info(`Moving item with guid ${bm.guid} to index ${newIndex}\n`);
+    try {
+      bm.index = newIndex;
+      await PlacesUtils.bookmarks.update(bm);
+      if (newIndex < -1) {
+        do_throw("Moving an item to a negative index should throw\n");
+      }
+    } catch (ex) {
+      if (newIndex >= -1) {
+        do_throw("Moving an item to a valid index should not throw\n");
+      }
+    }
+  }
+  await check_contiguous_indexes(bookmarks);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmark_observer.js b/toolkit/components/places/tests/bookmarks/test_bookmark_observer.js
new file mode 100644
index 0000000000..0bd4b94be0
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmark_observer.js
@@ -0,0 +1,1162 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that each bookmark event gets the correct input.
+
+var gUnfiledFolderId;
+
+var gBookmarksObserver = {
+  expected: [],
+  setup(expected) {
+    this.expected = expected;
+    this.deferred = Promise.withResolvers();
+    return this.deferred.promise;
+  },
+
+  validateEvents(events) {
+    Assert.greaterOrEqual(this.expected.length, events.length);
+    for (let event of events) {
+      let expected = this.expected.shift();
+      Assert.equal(expected.eventType, event.type);
+      let args = expected.args;
+      for (let i = 0; i < args.length; i++) {
+        Assert.ok(
+          args[i].check(event[args[i].name]),
+          event.type + "(args[" + i + "]: " + args[i].name + ")"
+        );
+      }
+    }
+
+    if (this.expected.length === 0) {
+      this.deferred.resolve();
+    }
+  },
+
+  handlePlacesEvents(events) {
+    this.validateEvents(events);
+  },
+};
+
+var gBookmarkSkipObserver = {
+  expected: null,
+  setup(expected) {
+    this.expected = expected;
+    this.deferred = Promise.withResolvers();
+    return this.deferred.promise;
+  },
+
+  validateEvents(events) {
+    events = events.filter(e => !e.isTagging);
+    Assert.greaterOrEqual(this.expected.length, events.length);
+    for (let event of events) {
+      let expectedEventType = this.expected.shift();
+      Assert.equal(expectedEventType, event.type);
+    }
+
+    if (this.expected.length === 0) {
+      this.deferred.resolve();
+    }
+  },
+
+  handlePlacesEvents(events) {
+    this.validateEvents(events);
+  },
+};
+
+add_task(async function setup() {
+  gUnfiledFolderId = await PlacesTestUtils.promiseItemId(
+    PlacesUtils.bookmarks.unfiledGuid
+  );
+  gBookmarksObserver.handlePlacesEvents =
+    gBookmarksObserver.handlePlacesEvents.bind(gBookmarksObserver);
+  gBookmarkSkipObserver.handlePlacesEvents =
+    gBookmarkSkipObserver.handlePlacesEvents.bind(gBookmarkSkipObserver);
+  PlacesUtils.observers.addListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-tags-changed",
+      "bookmark-title-changed",
+    ],
+    gBookmarksObserver.handlePlacesEvents
+  );
+  PlacesUtils.observers.addListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-tags-changed",
+      "bookmark-title-changed",
+    ],
+    gBookmarkSkipObserver.handlePlacesEvents
+  );
+});
+
+add_task(async function bookmarkItemAdded_bookmark() {
+  const title = "Bookmark 1";
+  let uri = Services.io.newURI("http://1.mozilla.org/");
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-added"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v === title },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "tags",
+            check: v => v === "",
+          },
+          {
+            name: "frecency",
+            check: v => v === 1,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 0,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === null,
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: uri,
+    title,
+  });
+  await promise;
+});
+
+add_task(async function bookmarkItemAdded_separator() {
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-added"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 1 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v === "" },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "tags",
+            check: v => v === "",
+          },
+          {
+            name: "frecency",
+            check: v => v === 0,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 0,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === null,
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  await promise;
+});
+
+add_task(async function bookmarkItemAdded_folder() {
+  const title = "Folder 1";
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-added"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 2 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v === title },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "tags",
+            check: v => v === "",
+          },
+          {
+            name: "frecency",
+            check: v => v === 0,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 0,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === null,
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  await promise;
+});
+
+add_task(async function bookmarkTitleChanged() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  const title = "New title";
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-title-changed"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-title-changed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "title", check: v => v === title },
+          { name: "lastModified", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.update({ guid: bm.guid, title });
+  await promise;
+});
+
+add_task(async function bookmarkTagsChanged() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  let uri = bm.url.URI;
+  const TAG = "tag";
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup([
+      "bookmark-tags-changed",
+      "bookmark-tags-changed",
+    ]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added", // This is the tag folder.
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === PlacesUtils.tagsFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v === TAG },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-added", // This is the tag.
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v === "" },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-tags-changed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          { name: "lastModified", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "isTagging",
+            check: v => v === false,
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed", // This is the tag.
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v == "" },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-tags-changed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          { name: "lastModified", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "isTagging",
+            check: v => v === false,
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed", // This is the tag folder.
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === PlacesUtils.tagsFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v == TAG },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  PlacesUtils.tagging.tagURI(uri, [TAG]);
+  PlacesUtils.tagging.untagURI(uri, [TAG]);
+  await promise;
+});
+
+add_task(async function bookmarkItemMoved_bookmark() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-moved", "bookmark-moved"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-moved",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "oldIndex", check: v => v === 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "oldParentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          { name: "url", check: v => typeof v == "string" },
+          {
+            name: "title",
+            check: v => v == bm.title,
+          },
+          {
+            name: "tags",
+            check: v => v === "",
+          },
+          {
+            name: "frecency",
+            check: v => v === 1,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 0,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === null,
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-moved",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "oldIndex", check: v => v === 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "oldParentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          { name: "url", check: v => typeof v == "string" },
+          {
+            name: "title",
+            check: v => v == bm.title,
+          },
+          {
+            name: "tags",
+            check: v => v === "",
+          },
+          {
+            name: "frecency",
+            check: v => v === 1,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 0,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === null,
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    index: 0,
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  await promise;
+});
+
+add_task(async function bookmarkItemRemoved_bookmark() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  let uri = bm.url.URI;
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-removed"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v === uri.spec },
+          { name: "title", check: v => v == "New title" },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.remove(bm);
+  await promise;
+});
+
+add_task(async function bookmarkItemRemoved_separator() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-removed"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v == "" },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.remove(bm);
+  await promise;
+});
+
+add_task(async function bookmarkItemRemoved_folder() {
+  let bm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-removed"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v == "Folder 1" },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  await PlacesUtils.bookmarks.remove(bm);
+  await promise;
+});
+
+add_task(async function bookmarkItemRemoved_folder_recursive() {
+  const title = "Folder 3";
+  const BMTITLE = "Bookmark 1";
+  let uri = Services.io.newURI("http://1.mozilla.org/");
+  let promise = Promise.all([
+    gBookmarkSkipObserver.setup([
+      "bookmark-added",
+      "bookmark-added",
+      "bookmark-added",
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-removed",
+      "bookmark-removed",
+      "bookmark-removed",
+    ]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v === title },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v === BMTITLE },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 1 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v === title },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v === BMTITLE },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v === uri.spec },
+          { name: "title", check: v => v == BMTITLE },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 1 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v == title },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v === uri.spec },
+          { name: "title", check: v => v == BMTITLE },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+      {
+        eventType: "bookmark-removed",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => typeof v == "number" && v > 0 },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+          { name: "url", check: v => v === "" },
+          { name: "title", check: v => v == title },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+        ],
+      },
+    ]),
+  ]);
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: uri,
+    title: BMTITLE,
+  });
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    title,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: folder2.guid,
+    url: uri,
+    title: BMTITLE,
+  });
+
+  await PlacesUtils.bookmarks.remove(folder);
+  await promise;
+});
+
+add_task(async function bookmarkItemAdded_tagged_visited_bookmark() {
+  const now = new Date();
+  const uri = Services.io.newURI("http://tagged_visited.mozilla.org/");
+  const title = "Tagged and Visited";
+  const tags = ["a", "b", "c"];
+
+  const promise = Promise.all([
+    gBookmarkSkipObserver.setup(["bookmark-added"]),
+    gBookmarksObserver.setup([
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "title", check: v => v === tags[0] },
+          { name: "url", check: v => v === "" },
+        ],
+      },
+      {
+        eventType: "bookmark-added", // This is the tag.
+        args: [
+          { name: "title", check: v => v === "" },
+          { name: "url", check: v => v === uri.spec },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "title", check: v => v === tags[1] },
+          { name: "url", check: v => v === "" },
+        ],
+      },
+      {
+        eventType: "bookmark-added", // This is the tag.
+        args: [
+          { name: "title", check: v => v === "" },
+          { name: "url", check: v => v === uri.spec },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "title", check: v => v === tags[2] },
+          { name: "url", check: v => v === "" },
+        ],
+      },
+      {
+        eventType: "bookmark-added", // This is the tag.
+        args: [
+          { name: "title", check: v => v === "" },
+          { name: "url", check: v => v === uri.spec },
+        ],
+      },
+      {
+        eventType: "bookmark-added",
+        args: [
+          { name: "id", check: v => typeof v == "number" && v > 0 },
+          { name: "parentId", check: v => v === gUnfiledFolderId },
+          { name: "index", check: v => v === 0 },
+          {
+            name: "itemType",
+            check: v => v === PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          },
+          { name: "url", check: v => v == uri.spec },
+          { name: "title", check: v => v === title },
+          { name: "dateAdded", check: v => typeof v == "number" && v > 0 },
+          {
+            name: "guid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "parentGuid",
+            check: v => typeof v == "string" && PlacesUtils.isValidGuid(v),
+          },
+          {
+            name: "source",
+            check: v =>
+              Object.values(PlacesUtils.bookmarks.SOURCES).includes(v),
+          },
+          {
+            name: "tags",
+            check: v => v === tags.join(),
+          },
+          {
+            name: "frecency",
+            check: v => v > 1,
+          },
+          {
+            name: "hidden",
+            check: v => v === false,
+          },
+          {
+            name: "visitCount",
+            check: v => v === 1,
+          },
+          {
+            name: "lastVisitDate",
+            check: v => v === now.getTime(),
+          },
+        ],
+      },
+    ]),
+  ]);
+
+  PlacesUtils.tagging.tagURI(uri, tags);
+  await PlacesUtils.history.insert({
+    url: uri.spec,
+    title,
+    visits: [{ date: now }],
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: uri,
+    title,
+  });
+
+  await promise;
+});
+
+add_task(function cleanup() {
+  PlacesUtils.observers.removeListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-tags-changed",
+      "bookmark-title-changed",
+    ],
+    gBookmarksObserver.handlePlacesEvents
+  );
+  PlacesUtils.observers.removeListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-tags-changed",
+      "bookmark-title-changed",
+    ],
+    gBookmarkSkipObserver.handlePlacesEvents
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_eraseEverything.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_eraseEverything.js
new file mode 100644
index 0000000000..955909f8c3
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_eraseEverything.js
@@ -0,0 +1,199 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_eraseEverything() {
+  await PlacesTestUtils.addVisits({
+    uri: NetUtil.newURI("http://example.com/"),
+  });
+  await PlacesTestUtils.addVisits({
+    uri: NetUtil.newURI("http://mozilla.org/"),
+  });
+  let frecencyForExample = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url: "http://example.com/" }
+  );
+  let frecencyForMozilla = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url: "http://mozilla.org/" }
+  );
+  Assert.ok(frecencyForExample > 0);
+  Assert.ok(frecencyForMozilla > 0);
+  let unfiledFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(unfiledFolder);
+  let unfiledBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+  });
+  checkBookmarkObject(unfiledBookmark);
+  let unfiledBookmarkInFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: unfiledFolder.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://mozilla.org/",
+  });
+  checkBookmarkObject(unfiledBookmarkInFolder);
+
+  let menuFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(menuFolder);
+  let menuBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+  });
+  checkBookmarkObject(menuBookmark);
+  let menuBookmarkInFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: menuFolder.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://mozilla.org/",
+  });
+  checkBookmarkObject(menuBookmarkInFolder);
+
+  let toolbarFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(toolbarFolder);
+  let toolbarBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+  });
+  checkBookmarkObject(toolbarBookmark);
+  let toolbarBookmarkInFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: toolbarFolder.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://mozilla.org/",
+  });
+  checkBookmarkObject(toolbarBookmarkInFolder);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://example.com/",
+    })) > frecencyForExample
+  );
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://example.com/",
+    })) > frecencyForMozilla
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://example.com/",
+    }),
+    frecencyForExample
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://example.com/",
+    }),
+    frecencyForMozilla
+  );
+});
+
+add_task(async function test_eraseEverything_roots() {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Ensure the roots have not been removed.
+  Assert.ok(
+    await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.unfiledGuid)
+  );
+  Assert.ok(
+    await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.toolbarGuid)
+  );
+  Assert.ok(await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.menuGuid));
+  Assert.ok(await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.tagsGuid));
+  Assert.ok(await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.rootGuid));
+});
+
+add_task(async function test_eraseEverything_reparented() {
+  // Create a folder with 1 bookmark in it...
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let bookmark1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    url: "http://example.com/",
+  });
+  // ...and a second folder.
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  // Reparent the bookmark to the 2nd folder.
+  bookmark1.parentGuid = folder2.guid;
+  await PlacesUtils.bookmarks.update(bookmark1);
+
+  // Erase everything.
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_notifications() {
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "test",
+        url: "http://example.com",
+      },
+      {
+        title: "folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "test2",
+            url: "http://example.com/2",
+          },
+        ],
+      },
+    ],
+  });
+
+  let skipDescendantsObserver = expectPlacesObserverNotifications(
+    ["bookmark-removed"],
+    false,
+    true
+  );
+  let receiveAllObserver = expectPlacesObserverNotifications(
+    ["bookmark-removed"],
+    false
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let expectedNotifications = [
+    {
+      type: "bookmark-removed",
+      guid: bms[1].guid,
+    },
+    {
+      type: "bookmark-removed",
+      guid: bms[0].guid,
+    },
+  ];
+
+  // If we're skipping descendents, we'll only be notified of the folder.
+  skipDescendantsObserver.check(expectedNotifications);
+
+  // Note: Items of folders get notified first.
+  expectedNotifications.unshift({
+    type: "bookmark-removed",
+    guid: bms[2].guid,
+  });
+
+  receiveAllObserver.check(expectedNotifications);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js
new file mode 100644
index 0000000000..2083856a99
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_fetch.js
@@ -0,0 +1,599 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+var gAccumulator = {
+  get callback() {
+    this.results = [];
+    return result => this.results.push(result);
+  },
+};
+
+add_task(async function invalid_input_throws() {
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch(),
+    /Input should be a valid object/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch(null),
+    /Input should be a valid object/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guid: "123456789012", index: 0 }),
+    /The following properties were expected: parentGuid/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({}),
+    /Unexpected number of conditions provided: 0/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    }),
+    /Unexpected number of conditions provided: 0/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({
+      guid: "123456789012",
+      parentGuid: "012345678901",
+      index: 0,
+    }),
+    /Unexpected number of conditions provided: 2/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({
+      guid: "123456789012",
+      url: "http://example.com",
+    }),
+    /Unexpected number of conditions provided: 2/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch("test"),
+    /Invalid value for property 'guid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch(123),
+    /Invalid value for property 'guid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guid: "test" }),
+    /Invalid value for property 'guid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guid: null }),
+    /Invalid value for property 'guid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guid: 123 }),
+    /Invalid value for property 'guid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guidPrefix: "" }),
+    /Invalid value for property 'guidPrefix'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guidPrefix: null }),
+    /Invalid value for property 'guidPrefix'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guidPrefix: 123 }),
+    /Invalid value for property 'guidPrefix'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guidPrefix: "123456789012" }),
+    /Invalid value for property 'guidPrefix'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ guidPrefix: "@" }),
+    /Invalid value for property 'guidPrefix'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: "test", index: 0 }),
+    /Invalid value for property 'parentGuid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: null, index: 0 }),
+    /Invalid value for property 'parentGuid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: 123, index: 0 }),
+    /Invalid value for property 'parentGuid'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: "123456789012", index: "0" }),
+    /Invalid value for property 'index'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: "123456789012", index: null }),
+    /Invalid value for property 'index'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ parentGuid: "123456789012", index: -10 }),
+    /Invalid value for property 'index'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ url: "http://te st/" }),
+    /Invalid value for property 'url'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ url: null }),
+    /Invalid value for property 'url'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ url: -10 }),
+    /Invalid value for property 'url'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch("123456789012", "test"),
+    /onResult callback must be a valid function/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch("123456789012", {}),
+    /onResult callback must be a valid function/
+  );
+});
+
+add_task(async function fetch_nonexistent_guid() {
+  let bm = await PlacesUtils.bookmarks.fetch(
+    { guid: "123456789012" },
+    gAccumulator.callback
+  );
+  Assert.equal(bm, null);
+  Assert.equal(gAccumulator.results.length, 0);
+});
+
+add_task(async function fetch_bookmark() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(bm1.guid, gAccumulator.callback);
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  checkBookmarkObject(gAccumulator.results[0]);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.index, 0);
+  Assert.deepEqual(bm2.dateAdded, bm2.lastModified);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm2.url.href, "http://example.com/");
+  Assert.equal(bm2.title, "a bookmark");
+  Assert.strictEqual(bm2.childCount, undefined);
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_bookmar_empty_title() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  checkBookmarkObject(bm2);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.index, 0);
+  Assert.strictEqual(bm2.title, "");
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_folder() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  checkBookmarkObject(bm1);
+  Assert.deepEqual(bm1.dateAdded, bm1.lastModified);
+
+  // Inserting a child updates both the childCount and lastModified of bm1,
+  // though the bm1 object is static once fetched, thus later we'll manually
+  // update it.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: bm1.guid,
+    url: "https://www.mozilla.org/",
+    title: "",
+  });
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  checkBookmarkObject(bm2);
+
+  Assert.equal(bm2.childCount, 1);
+  bm1.childCount = bm2.childCount;
+  bm1.lastModified = bm2.lastModified;
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.index, 0);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+  Assert.equal(bm2.title, "a folder");
+  Assert.ok(!("url" in bm2));
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_folder_empty_title() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  checkBookmarkObject(bm2);
+
+  Assert.equal(bm2.childCount, 0);
+  // Insert doesn't populate childCount (it would always be 0 anyway), so set
+  // it to be able to just use deepEqual.
+  bm1.childCount = bm2.childCount;
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.index, 0);
+  Assert.strictEqual(bm2.title, "");
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_separator() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  checkBookmarkObject(bm2);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.index, 0);
+  Assert.deepEqual(bm2.dateAdded, bm2.lastModified);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+  Assert.ok(!("url" in bm2));
+  Assert.strictEqual(bm2.title, "");
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_byguid_prefix() {
+  const PREFIX = "PREFIX-";
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: PlacesUtils.generateGuidWithPrefix(PREFIX),
+    url: "http://bm1.example.com/",
+    title: "bookmark 1",
+  });
+  checkBookmarkObject(bm1);
+  Assert.ok(bm1.guid.startsWith(PREFIX));
+
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: PlacesUtils.generateGuidWithPrefix(PREFIX),
+    url: "http://bm2.example.com/",
+    title: "bookmark 2",
+  });
+  checkBookmarkObject(bm2);
+  Assert.ok(bm2.guid.startsWith(PREFIX));
+
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    guid: PlacesUtils.generateGuidWithPrefix(PREFIX),
+    title: "a folder",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: bm3.guid,
+    url: "https://www.mozilla.org/",
+    title: "",
+  });
+  checkBookmarkObject(bm3);
+  Assert.ok(bm3.guid.startsWith(PREFIX));
+
+  // Bookmark 4 doesn't have the same guid prefix, so it shouldn't be returned in the results.
+  let bm4 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://bm3.example.com/",
+    title: "bookmark 4",
+  });
+  checkBookmarkObject(bm4);
+  Assert.ok(!bm4.guid.startsWith(PREFIX));
+
+  await PlacesUtils.bookmarks.fetch(
+    { guidPrefix: PREFIX },
+    gAccumulator.callback
+  );
+
+  Assert.equal(gAccumulator.results.length, 3);
+
+  // The results are returned by most recent first, so the first bookmark
+  // inserted is the last one in the returned array.
+  Assert.deepEqual(bm1, gAccumulator.results[2]);
+  Assert.deepEqual(bm2, gAccumulator.results[1]);
+  Assert.equal(gAccumulator.results[0].childCount, 1);
+  bm3.childCount = gAccumulator.results[0].childCount;
+  bm3.lastModified = gAccumulator.results[0].lastModified;
+  Assert.deepEqual(bm3, gAccumulator.results[0]);
+
+  Assert.equal(bm3.childCount, 1);
+
+  await PlacesUtils.bookmarks.remove(bm1);
+  await PlacesUtils.bookmarks.remove(bm2);
+  await PlacesUtils.bookmarks.remove(bm3);
+  await PlacesUtils.bookmarks.remove(bm4);
+});
+
+add_task(async function fetch_byposition_nonexisting_parentGuid() {
+  let bm = await PlacesUtils.bookmarks.fetch(
+    { parentGuid: "123456789012", index: 0 },
+    gAccumulator.callback
+  );
+  Assert.equal(bm, null);
+  Assert.equal(gAccumulator.results.length, 0);
+});
+
+add_task(async function fetch_byposition_nonexisting_index() {
+  let bm = await PlacesUtils.bookmarks.fetch(
+    { parentGuid: PlacesUtils.bookmarks.unfiledGuid, index: 100 },
+    gAccumulator.callback
+  );
+  Assert.equal(bm, null);
+  Assert.equal(gAccumulator.results.length, 0);
+});
+
+add_task(async function fetch_byposition() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(
+    { parentGuid: bm1.parentGuid, index: bm1.index },
+    gAccumulator.callback
+  );
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  checkBookmarkObject(gAccumulator.results[0]);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.index, 0);
+  Assert.deepEqual(bm2.dateAdded, bm2.lastModified);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm2.url.href, "http://example.com/");
+  Assert.equal(bm2.title, "a bookmark");
+});
+
+add_task(async function fetch_byposition_default_index() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/last",
+    title: "last child",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(
+    { parentGuid: bm1.parentGuid, index: PlacesUtils.bookmarks.DEFAULT_INDEX },
+    gAccumulator.callback
+  );
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  checkBookmarkObject(gAccumulator.results[0]);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.index, 1);
+  Assert.deepEqual(bm2.dateAdded, bm2.lastModified);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm2.url.href, "http://example.com/last");
+  Assert.equal(bm2.title, "last child");
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+});
+
+add_task(async function fetch_byurl_nonexisting() {
+  let bm = await PlacesUtils.bookmarks.fetch(
+    { url: "http://nonexisting.com/" },
+    gAccumulator.callback
+  );
+  Assert.equal(bm, null);
+  Assert.equal(gAccumulator.results.length, 0);
+});
+
+add_task(async function fetch_byurl() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://byurl.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+
+  // Also ensure that fecth-by-url excludes the tags folder.
+  PlacesUtils.tagging.tagURI(bm1.url.URI, ["Test Tag"]);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback
+  );
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  checkBookmarkObject(gAccumulator.results[0]);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+
+  Assert.deepEqual(bm1, bm2);
+  Assert.equal(bm2.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.deepEqual(bm2.dateAdded, bm2.lastModified);
+  Assert.equal(bm2.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm2.url.href, "http://byurl.com/");
+  Assert.equal(bm2.title, "a bookmark");
+
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://byurl.com/",
+    title: "a bookmark",
+  });
+  let bm4 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback
+  );
+  checkBookmarkObject(bm4);
+  Assert.deepEqual(bm3, bm4);
+  Assert.equal(gAccumulator.results.length, 2);
+  gAccumulator.results.forEach(checkBookmarkObject);
+  Assert.deepEqual(gAccumulator.results[0], bm4);
+
+  // After an update the returned bookmark should change.
+  await PlacesUtils.bookmarks.update({ guid: bm1.guid, title: "new title" });
+  let bm5 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback
+  );
+  checkBookmarkObject(bm5);
+  // Cannot use deepEqual cause lastModified changed.
+  Assert.equal(bm1.guid, bm5.guid);
+  Assert.ok(bm5.lastModified > bm1.lastModified);
+  Assert.equal(gAccumulator.results.length, 2);
+  gAccumulator.results.forEach(checkBookmarkObject);
+  Assert.deepEqual(gAccumulator.results[0], bm5);
+
+  // cleanup
+  PlacesUtils.tagging.untagURI(bm1.url.URI, ["Test Tag"]);
+});
+
+add_task(async function fetch_concurrent() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://concurrent.url.com/",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback,
+    { concurrent: true }
+  );
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+  Assert.deepEqual(bm1, bm2);
+  let bm3 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback,
+    { concurrent: false }
+  );
+  checkBookmarkObject(bm3);
+  Assert.equal(gAccumulator.results.length, 1);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+  Assert.deepEqual(bm1, bm3);
+  let bm4 = await PlacesUtils.bookmarks.fetch(
+    { url: bm1.url },
+    gAccumulator.callback,
+    {}
+  );
+  checkBookmarkObject(bm4);
+  Assert.equal(gAccumulator.results.length, 1);
+  Assert.deepEqual(gAccumulator.results[0], bm1);
+  Assert.deepEqual(bm1, bm4);
+});
+
+add_task(async function fetch_by_parent() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  checkBookmarkObject(folder1);
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    url: "http://bm1.example.com/",
+    title: "bookmark 1",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    url: "http://bm2.example.com/",
+    title: "bookmark 2",
+  });
+  checkBookmarkObject(bm2);
+
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "sub folder",
+    index: 0,
+  });
+  checkBookmarkObject(bm2);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: bm3.guid,
+    url: "http://mozilla.org/",
+    title: "sub bookmark",
+  });
+
+  await PlacesUtils.bookmarks.fetch(
+    { parentGuid: folder1.guid },
+    gAccumulator.callback
+  );
+
+  Assert.equal(gAccumulator.results.length, 3);
+
+  Assert.equal(gAccumulator.results[0].childCount, 1);
+  bm3.childCount = gAccumulator.results[0].childCount;
+  bm3.lastModified = gAccumulator.results[0].lastModified;
+  Assert.deepEqual(bm3, gAccumulator.results[0]);
+  Assert.equal(bm1.url.href, gAccumulator.results[1].url.href);
+  Assert.equal(bm2.url.href, gAccumulator.results[2].url.href);
+
+  await PlacesUtils.bookmarks.remove(folder1);
+});
+
+add_task(async function fetch_with_bookmark_path() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "Parent",
+  });
+  checkBookmarkObject(folder1);
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    url: "http://bookmarkpath.example.com/",
+    title: "Child Bookmark",
+  });
+  checkBookmarkObject(bm1);
+
+  let bm2 = await PlacesUtils.bookmarks.fetch(
+    { guid: bm1.guid },
+    gAccumulator.callback,
+    { includePath: true }
+  );
+  checkBookmarkObject(bm2);
+  Assert.equal(gAccumulator.results.length, 1);
+  Assert.equal(bm2.path.length, 2);
+  Assert.equal(bm2.path[0].guid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm2.path[0].title, "unfiled");
+  Assert.equal(bm2.path[1].guid, folder1.guid);
+  Assert.equal(bm2.path[1].title, folder1.title);
+
+  await PlacesUtils.bookmarks.remove(folder1);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_getRecent.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_getRecent.js
new file mode 100644
index 0000000000..55cddb8820
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_getRecent.js
@@ -0,0 +1,117 @@
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.getRecent(),
+    /numberOfItems argument is required/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.getRecent("abc"),
+    /numberOfItems argument must be an integer/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.getRecent(1.2),
+    /numberOfItems argument must be an integer/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.getRecent(0),
+    /numberOfItems argument must be greater than zero/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.getRecent(-1),
+    /numberOfItems argument must be greater than zero/
+  );
+});
+
+add_task(async function getRecent_returns_recent_bookmarks() {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/path",
+    title: "another bookmark",
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.net/",
+    title: "another bookmark",
+  });
+  let bm4 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.net/path",
+    title: "yet another bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+  checkBookmarkObject(bm3);
+  checkBookmarkObject(bm4);
+
+  // Add a tag to the most recent url to prove it doesn't get returned.
+  PlacesUtils.tagging.tagURI(uri(bm4.url), ["Test Tag"]);
+
+  // Add a separator.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+
+  // Add a query bookmark.
+  let queryURL = `place:parent=${PlacesUtils.bookmarks.menuGuid}&queryType=1`;
+  let bm5 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: queryURL,
+    title: "a test query",
+  });
+  checkBookmarkObject(bm5);
+
+  // Verify that getRecent only returns actual bookmarks.
+  let results = await PlacesUtils.bookmarks.getRecent(100);
+  Assert.equal(
+    results.length,
+    4,
+    "The expected number of bookmarks was returned."
+  );
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(
+    bm4,
+    results[0],
+    "The first result is the expected bookmark."
+  );
+  checkBookmarkObject(results[1]);
+  Assert.deepEqual(
+    bm3,
+    results[1],
+    "The second result is the expected bookmark."
+  );
+  checkBookmarkObject(results[2]);
+  Assert.deepEqual(
+    bm2,
+    results[2],
+    "The third result is the expected bookmark."
+  );
+  checkBookmarkObject(results[3]);
+  Assert.deepEqual(
+    bm1,
+    results[3],
+    "The fourth result is the expected bookmark."
+  );
+
+  // Verify that getRecent utilizes the numberOfItems argument.
+  results = await PlacesUtils.bookmarks.getRecent(1);
+  Assert.equal(
+    results.length,
+    1,
+    "The expected number of bookmarks was returned."
+  );
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(
+    bm4,
+    results[0],
+    "The first result is the expected bookmark."
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js
new file mode 100644
index 0000000000..df99a5fe3d
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_insert.js
@@ -0,0 +1,432 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert(),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert(null),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({}),
+    /The following properties were expected/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ guid: "test" }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ guid: null }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ guid: 123 }),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ parentGuid: "test" }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ parentGuid: null }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ parentGuid: 123 }),
+    /Invalid value for property 'parentGuid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ index: "1" }),
+    /Invalid value for property 'index'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ index: -10 }),
+    /Invalid value for property 'index'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ dateAdded: -10 }),
+    /Invalid value for property 'dateAdded'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ dateAdded: "today" }),
+    /Invalid value for property 'dateAdded'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ dateAdded: Date.now() }),
+    /Invalid value for property 'dateAdded'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ dateAdded: new Date(NaN) }),
+    /Invalid value for property 'dateAdded'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ lastModified: -10 }),
+    /Invalid value for property 'lastModified'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ lastModified: "today" }),
+    /Invalid value for property 'lastModified'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ lastModified: Date.now() }),
+    /Invalid value for property 'lastModified'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ lastModified: new Date(NaN) }),
+    /Invalid value for property 'lastModified'/
+  );
+
+  let past = new Date(Date.now() - 86400000);
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ lastModified: past }),
+    /Invalid value for property 'lastModified'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ type: -1 }),
+    /Invalid value for property 'type'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ type: 100 }),
+    /Invalid value for property 'type'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.insert({ type: "bookmark" }),
+    /Invalid value for property 'type'/
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title: -1,
+      }),
+    /Invalid value for property 'title'/
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: 10,
+      }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: "http://te st",
+      }),
+    /Invalid value for property 'url'/
+  );
+  let longurl = "http://www.example.com/";
+  for (let i = 0; i < 65536; i++) {
+    longurl += "a";
+  }
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: longurl,
+      }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: NetUtil.newURI(longurl),
+      }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: "te st",
+      }),
+    /Invalid value for property 'url'/
+  );
+});
+
+add_task(async function invalid_properties_for_bookmark_type() {
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        url: "http://www.moz.com/",
+      }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        url: "http://www.moz.com/",
+      }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        title: "test",
+      }),
+    /Invalid value for property 'title'/
+  );
+});
+
+add_task(async function test_insert_into_root_throws() {
+  const { sinon } = ChromeUtils.importESModule(
+    "resource://testing-common/Sinon.sys.mjs"
+  );
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(PlacesUtils, "isInAutomation").get(() => false);
+  registerCleanupFunction(() => sandbox.restore());
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.rootGuid,
+        url: "http://example.com",
+      }),
+    /Invalid value for property 'parentGuid'/,
+    "Should throw when inserting a bookmark into the root."
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.rootGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      }),
+    /Invalid value for property 'parentGuid'/,
+    "Should throw when inserting a folder into the root."
+  );
+  sandbox.restore();
+});
+
+add_task(async function long_title_trim() {
+  let longtitle = "a";
+  for (let i = 0; i < 4096; i++) {
+    longtitle += "a";
+  }
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: longtitle,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 0);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+  Assert.equal(bm.title.length, 4096, "title should have been trimmed");
+  Assert.ok(!("url" in bm), "url should not be set");
+});
+
+add_task(async function create_separator() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 1);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function create_separator_w_title_fail() {
+  try {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      title: "a separator",
+    });
+    Assert.ok(false, "Trying to set title for a separator should reject");
+  } catch (ex) {}
+});
+
+add_task(async function create_separator_invalid_parent_fail() {
+  try {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: "123456789012",
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      title: "a separator",
+    });
+    Assert.ok(
+      false,
+      "Trying to create an item in a non existing parent reject"
+    );
+  } catch (ex) {}
+});
+
+add_task(async function create_separator_given_guid() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    guid: "123456789012",
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.guid, "123456789012");
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 2);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function create_item_given_guid_no_type_fail() {
+  try {
+    await PlacesUtils.bookmarks.insert({ parentGuid: "123456789012" });
+    Assert.ok(
+      false,
+      "Trying to create an item with a given guid but no type should reject"
+    );
+  } catch (ex) {}
+});
+
+add_task(async function create_separator_big_index() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    index: 9999,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 3);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function create_separator_given_dateAdded() {
+  let time = new Date();
+  let past = new Date(time - 86400000);
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    dateAdded: past,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.dateAdded, past);
+  Assert.equal(bm.lastModified, past);
+});
+
+add_task(async function create_folder() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+  Assert.strictEqual(bm.title, "");
+
+  // And then create a nested folder.
+  let parentGuid = bm.guid;
+  bm = await PlacesUtils.bookmarks.insert({
+    parentGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, parentGuid);
+  Assert.equal(bm.index, 0);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+  Assert.strictEqual(bm.title, "a folder");
+});
+
+add_task(async function create_bookmark() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let parentGuid = bm.guid;
+
+  bm = await PlacesUtils.bookmarks.insert({
+    parentGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, parentGuid);
+  Assert.equal(bm.index, 0);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm.url.href, "http://example.com/");
+  Assert.equal(bm.title, "a bookmark");
+
+  // Check parent lastModified.
+  let parent = await PlacesUtils.bookmarks.fetch({ guid: bm.parentGuid });
+  Assert.deepEqual(parent.lastModified, bm.dateAdded);
+
+  bm = await PlacesUtils.bookmarks.insert({
+    parentGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: new URL("http://example.com/"),
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, parentGuid);
+  Assert.equal(bm.index, 1);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm.url.href, "http://example.com/");
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function create_bookmark_frecency() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.greater(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: bm.url,
+    }),
+    0,
+    "Check frecency has been updated"
+  );
+});
+
+add_task(async function create_bookmark_without_type() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm.url.href, "http://example.com/");
+  Assert.equal(bm.title, "a bookmark");
+});
+
+add_task(async function test_url_with_apices() {
+  // Apices may confuse code and cause injection if mishandled.
+  const url = `javascript:alert("%s");alert('%s');`;
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  // Just a sanity check, this should not throw.
+  await PlacesUtils.history.remove(url);
+  let bm = await PlacesUtils.bookmarks.fetch({ url });
+  await PlacesUtils.bookmarks.remove(bm);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_insertTree.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_insertTree.js
new file mode 100644
index 0000000000..bb3c1dbe1f
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_insertTree.js
@@ -0,0 +1,590 @@
+add_task(async function invalid_input_rejects() {
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(),
+    /Should be provided a valid tree object./
+  );
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(null),
+    /Should be provided a valid tree object./
+  );
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree("foo"),
+    /Should be provided a valid tree object./
+  );
+
+  // All subsequent tests pass a valid parent guid.
+  let guid = PlacesUtils.bookmarks.unfiledGuid;
+
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree({ guid, children: [] }),
+    /Should have a non-zero number of children to insert./
+  );
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree({ guid }),
+    /Should have a non-zero number of children to insert./
+  );
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree({ children: [{}], guid }),
+    /The following properties were expected: url/
+  );
+
+  // Reuse another variable to make this easier to read:
+  let tree = { guid, children: [{ guid: "test" }] };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'guid'/
+  );
+  tree.children = [{ guid: null }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'guid'/
+  );
+  tree.children = [{ guid: 123 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'guid'/
+  );
+
+  tree.children = [{ dateAdded: -10 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'dateAdded'/
+  );
+  tree.children = [{ dateAdded: "today" }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'dateAdded'/
+  );
+  tree.children = [{ dateAdded: Date.now() }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'dateAdded'/
+  );
+  tree.children = [{ dateAdded: new Date(NaN) }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'dateAdded'/
+  );
+
+  tree.children = [{ lastModified: -10 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'lastModified'/
+  );
+  tree.children = [{ lastModified: "today" }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'lastModified'/
+  );
+  tree.children = [{ lastModified: Date.now() }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'lastModified'/
+  );
+
+  let time = Date.now();
+  let future = new Date(time + 86400000);
+  tree.children = [{ dateAdded: future, lastModified: time }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'dateAdded'/
+  );
+  let past = new Date(time - 86400000);
+  tree.children = [{ lastModified: past }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'lastModified'/
+  );
+
+  tree.children = [{ type: -1 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'type'/
+  );
+  tree.children = [{ type: 100 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'type'/
+  );
+  tree.children = [{ type: "bookmark" }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'type'/
+  );
+
+  tree.children = [{ type: PlacesUtils.bookmarks.TYPE_BOOKMARK, title: -1 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'title'/
+  );
+
+  tree.children = [{ type: PlacesUtils.bookmarks.TYPE_BOOKMARK, url: 10 }];
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(tree),
+    /Invalid value for property 'url'/
+  );
+
+  let treeWithBrokenURL = {
+    children: [
+      { type: PlacesUtils.bookmarks.TYPE_BOOKMARK, url: "http://te st" },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(treeWithBrokenURL),
+    /Invalid value for property 'url'/
+  );
+  let longurl = "http://www.example.com/" + "a".repeat(65536);
+  let treeWithLongURL = {
+    children: [{ type: PlacesUtils.bookmarks.TYPE_BOOKMARK, url: longurl }],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(treeWithLongURL),
+    /Invalid value for property 'url'/
+  );
+  let treeWithLongURI = {
+    children: [
+      {
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: NetUtil.newURI(longurl),
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(treeWithLongURI),
+    /Invalid value for property 'url'/
+  );
+  let treeWithOtherBrokenURL = {
+    children: [{ type: PlacesUtils.bookmarks.TYPE_BOOKMARK, url: "te st" }],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(treeWithOtherBrokenURL),
+    /Invalid value for property 'url'/
+  );
+});
+
+add_task(async function invalid_properties_for_bookmark_type() {
+  let folderWithURL = {
+    children: [
+      { type: PlacesUtils.bookmarks.TYPE_FOLDER, url: "http://www.moz.com/" },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(folderWithURL),
+    /Invalid value for property 'url'/
+  );
+  let separatorWithURL = {
+    children: [
+      {
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        url: "http://www.moz.com/",
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(separatorWithURL),
+    /Invalid value for property 'url'/
+  );
+  let separatorWithTitle = {
+    children: [{ type: PlacesUtils.bookmarks.TYPE_SEPARATOR, title: "test" }],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  await Assert.throws(
+    () => PlacesUtils.bookmarks.insertTree(separatorWithTitle),
+    /Invalid value for property 'title'/
+  );
+});
+
+add_task(async function create_separator() {
+  let [bm] = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 0);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function create_plain_bm() {
+  let [bm] = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        url: "http://www.example.com/",
+        title: "Test",
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 1);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+  Assert.equal(bm.title, "Test");
+  Assert.equal(bm.url.href, "http://www.example.com/");
+});
+
+add_task(async function create_folder() {
+  let [bm] = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Test",
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  Assert.equal(bm.index, 2);
+  Assert.equal(bm.dateAdded, bm.lastModified);
+  Assert.equal(bm.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+  Assert.equal(bm.title, "Test");
+});
+
+add_task(async function create_in_tags() {
+  await Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insertTree({
+        children: [
+          {
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            url: "http://www.example.com/",
+            title: "Test adding a tag",
+          },
+        ],
+        guid: PlacesUtils.bookmarks.tagsGuid,
+      }),
+    /Can't use insertTree to insert tags/
+  );
+  let guidForTag = (
+    await PlacesUtils.bookmarks.insert({
+      title: "test-tag",
+      url: "http://www.unused.com/",
+      parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    })
+  ).guid;
+  await Assert.rejects(
+    PlacesUtils.bookmarks.insertTree({
+      children: [
+        {
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          url: "http://www.example.com/",
+          title: "Test adding an item to a tag",
+        },
+      ],
+      guid: guidForTag,
+    }),
+    /Can't use insertTree to insert tags/
+  );
+  await PlacesUtils.bookmarks.remove(guidForTag);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function insert_into_root() {
+  await Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insertTree({
+        children: [
+          {
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            url: "http://www.example.com/",
+            title: "Test inserting into root",
+          },
+        ],
+        guid: PlacesUtils.bookmarks.rootGuid,
+      }),
+    /Can't insert into the root/
+  );
+});
+
+add_task(async function tree_where_separator_or_folder_has_kids() {
+  await Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insertTree({
+        children: [
+          {
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+            children: [
+              {
+                type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                url: "http://www.example.com/",
+                title: "Test inserting into separator",
+              },
+            ],
+          },
+        ],
+        guid: PlacesUtils.bookmarks.unfiledGuid,
+      }),
+    /Invalid value for property 'children'/
+  );
+
+  await Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.insertTree({
+        children: [
+          {
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            children: [
+              {
+                type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                url: "http://www.example.com/",
+                title: "Test inserting into separator",
+              },
+            ],
+          },
+        ],
+        guid: PlacesUtils.bookmarks.unfiledGuid,
+      }),
+    /Invalid value for property 'children'/
+  );
+});
+
+add_task(async function create_hierarchy() {
+  let obsInvoked = 0;
+  let listener = events => {
+    for (let event of events) {
+      obsInvoked++;
+      Assert.greater(event.id, 0, "Should have a valid itemId");
+    }
+  };
+  PlacesUtils.observers.addListener(["bookmark-added"], listener);
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Root item",
+        children: [
+          {
+            url: "http://www.example.com/1",
+            title: "BM 1",
+          },
+          {
+            url: "http://www.example.com/2",
+            title: "BM 2",
+          },
+          {
+            title: "Sub",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            children: [
+              {
+                title: "Sub BM 1",
+                url: "http://www.example.com/sub/1",
+              },
+              {
+                title: "Sub BM 2",
+                url: "http://www.example.com/sub/2",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  PlacesUtils.observers.removeListener(["bookmark-added"], listener);
+  let parentFolder = null,
+    subFolder = null;
+  let prevBM = null;
+  for (let bm of bms) {
+    checkBookmarkObject(bm);
+    if (prevBM && prevBM.parentGuid == bm.parentGuid) {
+      Assert.equal(prevBM.index + 1, bm.index, "Indices should be subsequent");
+      Assert.equal(
+        (await PlacesUtils.bookmarks.fetch(bm.guid)).index,
+        bm.index,
+        "Index reflects inserted index"
+      );
+    }
+    prevBM = bm;
+    if (bm.type == PlacesUtils.bookmarks.TYPE_BOOKMARK) {
+      Assert.greater(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+          url: bm.url,
+        }),
+        0,
+        "Check frecency has been updated for bookmark " + bm.url
+      );
+    }
+    if (bm.title == "Root item") {
+      Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+      parentFolder = bm;
+    } else if (!bm.title.startsWith("Sub BM")) {
+      Assert.equal(bm.parentGuid, parentFolder.guid);
+      if (bm.type == PlacesUtils.bookmarks.TYPE_FOLDER) {
+        subFolder = bm;
+      }
+    } else {
+      Assert.equal(bm.parentGuid, subFolder.guid);
+    }
+  }
+  Assert.equal(obsInvoked, bms.length);
+  Assert.equal(obsInvoked, 6);
+});
+
+add_task(async function insert_many_non_nested() {
+  let obsInvoked = 0;
+  let listener = events => {
+    for (let event of events) {
+      obsInvoked++;
+      Assert.greater(event.id, 0, "Should have a valid itemId");
+    }
+  };
+  PlacesUtils.observers.addListener(["bookmark-added"], listener);
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        url: "http://www.example.com/1",
+        title: "Item 1",
+      },
+      {
+        url: "http://www.example.com/2",
+        title: "Item 2",
+      },
+      {
+        url: "http://www.example.com/3",
+        title: "Item 3",
+      },
+      {
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      },
+      {
+        title: "Item 4",
+        url: "http://www.example.com/4",
+      },
+      {
+        title: "Item 5",
+        url: "http://www.example.com/5",
+      },
+    ],
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  PlacesUtils.observers.removeListener(["bookmark-added"], listener);
+  let startIndex = -1;
+  for (let bm of bms) {
+    checkBookmarkObject(bm);
+    if (startIndex == -1) {
+      startIndex = bm.index;
+    } else {
+      Assert.equal(++startIndex, bm.index, "Indices should be subsequent");
+    }
+    Assert.equal(
+      (await PlacesUtils.bookmarks.fetch(bm.guid)).index,
+      bm.index,
+      "Index reflects inserted index"
+    );
+    if (bm.type == PlacesUtils.bookmarks.TYPE_BOOKMARK) {
+      Assert.greater(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+          url: bm.url,
+        }),
+        0,
+        "Check frecency has been updated for bookmark " + bm.url
+      );
+    }
+    Assert.equal(bm.parentGuid, PlacesUtils.bookmarks.unfiledGuid);
+  }
+  Assert.equal(obsInvoked, bms.length);
+  Assert.equal(obsInvoked, 6);
+});
+
+add_task(async function create_in_folder() {
+  let mozFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "Mozilla",
+  });
+
+  let notifications = [];
+  let listener = events => {
+    for (let event of events) {
+      notifications.push({
+        itemId: event.id,
+        parentId: event.parentId,
+        index: event.index,
+        title: event.title,
+        guid: event.guid,
+        parentGuid: event.parentGuid,
+      });
+    }
+  };
+  PlacesUtils.observers.addListener(["bookmark-added"], listener);
+
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    children: [
+      {
+        url: "http://getfirefox.com",
+        title: "Get Firefox!",
+      },
+      {
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Community",
+        children: [
+          {
+            url: "http://getthunderbird.com",
+            title: "Get Thunderbird!",
+          },
+          {
+            url: "https://www.seamonkey-project.org",
+            title: "SeaMonkey",
+          },
+        ],
+      },
+    ],
+    guid: mozFolder.guid,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  PlacesUtils.observers.removeListener(["bookmark-added"], listener);
+
+  let mozFolderId = await PlacesTestUtils.promiseItemId(mozFolder.guid);
+  let commFolderId = await PlacesTestUtils.promiseItemId(bms[1].guid);
+  deepEqual(notifications, [
+    {
+      itemId: await PlacesTestUtils.promiseItemId(bms[0].guid),
+      parentId: mozFolderId,
+      index: 0,
+      title: "Get Firefox!",
+      guid: bms[0].guid,
+      parentGuid: mozFolder.guid,
+    },
+    {
+      itemId: commFolderId,
+      parentId: mozFolderId,
+      index: 1,
+      title: "Community",
+      guid: bms[1].guid,
+      parentGuid: mozFolder.guid,
+    },
+    {
+      itemId: await PlacesTestUtils.promiseItemId(bms[2].guid),
+      parentId: commFolderId,
+      index: 0,
+      title: "Get Thunderbird!",
+      guid: bms[2].guid,
+      parentGuid: bms[1].guid,
+    },
+    {
+      itemId: await PlacesTestUtils.promiseItemId(bms[3].guid),
+      parentId: commFolderId,
+      index: 1,
+      title: "SeaMonkey",
+      guid: bms[3].guid,
+      parentGuid: bms[1].guid,
+    },
+  ]);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_moveToFolder.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_moveToFolder.js
new file mode 100644
index 0000000000..422aded45e
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_moveToFolder.js
@@ -0,0 +1,733 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const BOOKMARK_DATE_ADDED = new Date();
+
+function ensurePosition(info, parentGuid, index) {
+  print(`Checking ${info.guid}`);
+  checkBookmarkObject(info);
+  Assert.equal(
+    info.parentGuid,
+    parentGuid,
+    "Should be in the correct parent folder"
+  );
+  Assert.equal(info.index, index, "Should have the correct index");
+}
+
+function insertChildren(folder, items) {
+  if (!items.length) {
+    return [];
+  }
+
+  let children = [];
+  for (let i = 0; i < items.length; i++) {
+    if (items[i].type === TYPE_BOOKMARK) {
+      children.push({
+        title: `${i}`,
+        url: "http://example.com",
+        dateAdded: BOOKMARK_DATE_ADDED,
+      });
+    } else {
+      throw new Error(`Type ${items[i].type} is not supported.`);
+    }
+  }
+  return PlacesUtils.bookmarks.insertTree({
+    guid: folder.guid,
+    children,
+  });
+}
+
+async function dumpFolderChildren(
+  folder,
+  details,
+  folderA,
+  folderB,
+  originalAChildren,
+  originalBChildren
+) {
+  info(`${folder} Details:`);
+  info(`Input: ${JSON.stringify(details.initial[folder])}`);
+  info(`Expected: ${JSON.stringify(details.expected[folder])}`);
+  info("Index\tOriginal\tExpected\tResult");
+
+  let originalChildren;
+  let folderGuid;
+  if (folder == "folderA") {
+    originalChildren = originalAChildren;
+    folderGuid = folderA.guid;
+  } else {
+    originalChildren = originalBChildren;
+    folderGuid = folderB.guid;
+  }
+
+  let tree = await PlacesUtils.promiseBookmarksTree(folderGuid);
+  let childrenCount = tree.children ? tree.children.length : 0;
+  for (let i = 0; i < originalChildren.length || i < childrenCount; i++) {
+    let originalGuid =
+      i < originalChildren.length ? originalChildren[i].guid : "            ";
+    let resultGuid = i < childrenCount ? tree.children[i].guid : "            ";
+    let expectedGuid = "            ";
+    if (i < details.expected[folder].length) {
+      let expected = details.expected[folder][i];
+      expectedGuid =
+        expected.folder == "a"
+          ? originalAChildren[expected.originalIndex].guid
+          : originalBChildren[expected.originalIndex].guid;
+    }
+    info(`${i}\t${originalGuid}\t${expectedGuid}\t${resultGuid}\n`);
+  }
+}
+
+async function checkExpectedResults(
+  details,
+  folder,
+  folderGuid,
+  lastModified,
+  movedItems,
+  folderAChildren,
+  folderBChildren
+) {
+  let expectedResults = details.expected[folder];
+  for (let i = 0; i < expectedResults.length; i++) {
+    let expectedDetails = expectedResults[i];
+    let originalItem =
+      expectedDetails.folder == "a"
+        ? folderAChildren[expectedDetails.originalIndex]
+        : folderBChildren[expectedDetails.originalIndex];
+
+    // Check the item got updated correctly in the database.
+    let updatedItem = await PlacesUtils.bookmarks.fetch(originalItem.guid);
+
+    ensurePosition(updatedItem, folderGuid, i);
+    Assert.greaterOrEqual(
+      updatedItem.lastModified.getTime(),
+      lastModified.getTime(),
+      "Last modified should be later or equal to before"
+    );
+  }
+
+  if (details.expected.skipResultIndexChecks) {
+    return;
+  }
+
+  // Check the items returned from the actual move() call are correct.
+  let index = 0;
+  for (let item of details.initial[folder]) {
+    if (!("targetFolder" in item)) {
+      // We weren't moving this item, so skip it and continue.
+      continue;
+    }
+
+    let movedItem = movedItems[index];
+    let updatedItem = await PlacesUtils.bookmarks.fetch(movedItem.guid);
+
+    ensurePosition(movedItem, updatedItem.parentGuid, updatedItem.index);
+
+    index++;
+  }
+}
+
+async function checkLastModifiedForFolders(details, folder, movedItems) {
+  // For the tests, the moves always come from folderA.
+  if (
+    details.initial.folderA.some(
+      item => "targetFolder" in item && item.targetFolder == folder.title
+    )
+  ) {
+    let updatedFolder = await PlacesUtils.bookmarks.fetch(folder.guid);
+
+    Assert.greaterOrEqual(
+      updatedFolder.lastModified.getTime(),
+      folder.lastModified.getTime(),
+      "Should have updated the folder's last modified time."
+    );
+    print(JSON.stringify(movedItems[0]));
+    Assert.deepEqual(
+      updatedFolder.lastModified,
+      movedItems[0].lastModified,
+      "Should have the same last modified as the moved items."
+    );
+  }
+}
+
+async function testMoveToFolder(details) {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Always create two folders by default.
+  let [folderA, folderB] = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "a",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      },
+      {
+        title: "b",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      },
+    ],
+  });
+
+  checkBookmarkObject(folderA);
+  let folderAChildren = await insertChildren(folderA, details.initial.folderA);
+  checkBookmarkObject(folderB);
+  let folderBChildren = await insertChildren(folderB, details.initial.folderB);
+
+  const originalAChildren = folderAChildren.map(child => {
+    return { ...child };
+  });
+  const originalBChildren = folderBChildren.map(child => {
+    return { ...child };
+  });
+
+  let lastModified;
+  if (folderAChildren.length) {
+    lastModified = folderAChildren[0].lastModified;
+  } else if (folderBChildren.length) {
+    lastModified = folderBChildren[0].lastModified;
+  } else {
+    throw new Error("No children added, can't determine lastModified");
+  }
+
+  // Work out which children to move and to where.
+  let childrenToUpdate = [];
+  for (let i = 0; i < details.initial.folderA.length; i++) {
+    if ("move" in details.initial.folderA[i]) {
+      childrenToUpdate.push(folderAChildren[i].guid);
+    }
+  }
+
+  let observer;
+  if (details.notifications) {
+    observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+  }
+
+  let movedItems = await PlacesUtils.bookmarks.moveToFolder(
+    childrenToUpdate,
+    details.targetFolder == "a" ? folderA.guid : folderB.guid,
+    details.targetIndex
+  );
+
+  await dumpFolderChildren(
+    "folderA",
+    details,
+    folderA,
+    folderB,
+    originalAChildren,
+    originalBChildren
+  );
+  await dumpFolderChildren(
+    "folderB",
+    details,
+    folderA,
+    folderB,
+    originalAChildren,
+    originalBChildren
+  );
+
+  Assert.equal(movedItems.length, childrenToUpdate.length);
+  await checkExpectedResults(
+    details,
+    "folderA",
+    folderA.guid,
+    lastModified,
+    movedItems,
+    folderAChildren,
+    folderBChildren
+  );
+  await checkExpectedResults(
+    details,
+    "folderB",
+    folderB.guid,
+    lastModified,
+    movedItems,
+    folderAChildren,
+    folderBChildren
+  );
+
+  if (details.notifications) {
+    let expectedNotifications = [];
+
+    for (let notification of details.notifications) {
+      let origItem =
+        notification.originalFolder == "folderA"
+          ? originalAChildren[notification.originalIndex]
+          : originalBChildren[notification.originalIndex];
+      let newFolder = notification.newFolder == "folderA" ? folderA : folderB;
+
+      expectedNotifications.push({
+        type: "bookmark-moved",
+        id: await PlacesTestUtils.promiseItemId(origItem.guid),
+        itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url: origItem.url,
+        guid: origItem.guid,
+        parentGuid: newFolder.guid,
+        source: PlacesUtils.bookmarks.SOURCES.DEFAULT,
+        index: notification.newIndex,
+        oldParentGuid: origItem.parentGuid,
+        oldIndex: notification.originalIndex,
+        isTagging: false,
+        title: origItem.title,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: BOOKMARK_DATE_ADDED.getTime(),
+        lastVisitDate: null,
+      });
+    }
+    observer.check(expectedNotifications);
+  }
+
+  await checkLastModifiedForFolders(details, folderA, movedItems);
+  await checkLastModifiedForFolders(details, folderB, movedItems);
+}
+
+const TYPE_BOOKMARK = PlacesUtils.bookmarks.TYPE_BOOKMARK;
+
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder(),
+    /guids should be an array/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder({}),
+    /guids should be an array/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder([]),
+    /guids should be an array of at least one item/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder(["test"]),
+    /Expected only valid GUIDs to be passed/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder([null]),
+    /Expected only valid GUIDs to be passed/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder([123]),
+    /Expected only valid GUIDs to be passed/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.moveToFolder(["123456789012"], 123),
+    /Error: parentGuid should be a valid GUID/
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.moveToFolder(
+        ["123456789012"],
+        PlacesUtils.bookmarks.rootGuid
+      ),
+    /Cannot move bookmarks into root/
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.moveToFolder(["123456789012"], "123456789012", -2),
+    /index should be a number greater than/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.moveToFolder(
+        ["123456789012"],
+        "123456789012",
+        "sdffd"
+      ),
+    /index should be a number greater than/
+  );
+});
+
+add_task(async function test_move_nonexisting_bookmark_rejects() {
+  await Assert.rejects(
+    PlacesUtils.bookmarks.moveToFolder(["123456789012"], "123456789012", -1),
+    /No bookmarks found for the provided GUID/,
+    "Should reject when moving a non-existing bookmark"
+  );
+});
+
+add_task(async function test_move_folder_into_descendant_rejects() {
+  let parent = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let descendant = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  await Assert.rejects(
+    PlacesUtils.bookmarks.moveToFolder([parent.guid], parent.guid, 0),
+    /Cannot insert a folder into itself or one of its descendants/,
+    "Should reject when moving a folder into itself"
+  );
+
+  await Assert.rejects(
+    PlacesUtils.bookmarks.moveToFolder([parent.guid], descendant.guid, 0),
+    /Cannot insert a folder into itself or one of its descendants/,
+    "Should reject when moving a folder into a descendant"
+  );
+});
+
+add_task(async function test_move_from_differnt_with_no_target_rejects() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  await Assert.rejects(
+    PlacesUtils.bookmarks.moveToFolder([bm1.guid, bm2.guid], null, -1),
+    /All bookmarks should be in the same folder if no parent is specified/,
+    "Should reject when moving bookmarks from different folders with no target folder"
+  );
+});
+
+add_task(async function test_move_append_same_folder() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK },
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK },
+      ],
+      folderB: [],
+    },
+    targetFolder: "a",
+    targetIndex: -1,
+    expected: {
+      folderA: [
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 2 },
+        { folder: "a", originalIndex: 1 },
+      ],
+      folderB: [],
+    },
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 1,
+        newFolder: "folderA",
+        newIndex: 2,
+      },
+    ],
+  });
+});
+
+add_task(async function test_move_append_multiple_same_folder() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK },
+      ],
+      folderB: [],
+    },
+    targetFolder: "a",
+    targetIndex: -1,
+    expected: {
+      folderA: [
+        { folder: "a", originalIndex: 3 },
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 1 },
+        { folder: "a", originalIndex: 2 },
+      ],
+      folderB: [],
+    },
+    // These are all inserted at position 3 as that's what the views require
+    // to be notified, to ensure the new items are displayed in their correct
+    // positions.
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 0,
+        newFolder: "folderA",
+        newIndex: 3,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 1,
+        newFolder: "folderA",
+        newIndex: 3,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 2,
+        newFolder: "folderA",
+        newIndex: 3,
+      },
+    ],
+  });
+});
+
+add_task(async function test_move_append_multiple_new_folder() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+      ],
+      folderB: [],
+    },
+    targetFolder: "b",
+    targetIndex: -1,
+    expected: {
+      folderA: [],
+      folderB: [
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 1 },
+        { folder: "a", originalIndex: 2 },
+      ],
+    },
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 0,
+        newFolder: "folderB",
+        newIndex: 0,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 1,
+        newFolder: "folderB",
+        newIndex: 1,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 2,
+        newFolder: "folderB",
+        newIndex: 2,
+      },
+    ],
+  });
+});
+
+add_task(async function test_move_append_multiple_new_folder_with_existing() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK, move: true },
+      ],
+      folderB: [{ type: TYPE_BOOKMARK }, { type: TYPE_BOOKMARK }],
+    },
+    targetFolder: "b",
+    targetIndex: -1,
+    expected: {
+      folderA: [],
+      folderB: [
+        { folder: "b", originalIndex: 0 },
+        { folder: "b", originalIndex: 1 },
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 1 },
+        { folder: "a", originalIndex: 2 },
+      ],
+    },
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 0,
+        newFolder: "folderB",
+        newIndex: 2,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 1,
+        newFolder: "folderB",
+        newIndex: 3,
+      },
+      {
+        originalFolder: "folderA",
+        originalIndex: 2,
+        newFolder: "folderB",
+        newIndex: 4,
+      },
+    ],
+  });
+});
+
+add_task(async function test_move_insert_same_folder_up() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK },
+        { type: TYPE_BOOKMARK },
+        { type: TYPE_BOOKMARK, move: true },
+      ],
+      folderB: [],
+    },
+    targetFolder: "a",
+    targetIndex: 0,
+    expected: {
+      folderA: [
+        { folder: "a", originalIndex: 2 },
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 1 },
+      ],
+      folderB: [],
+    },
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 2,
+        newFolder: "folderA",
+        newIndex: 0,
+      },
+    ],
+  });
+});
+
+add_task(async function test_move_insert_same_folder_down() {
+  await testMoveToFolder({
+    initial: {
+      folderA: [
+        { type: TYPE_BOOKMARK, move: true },
+        { type: TYPE_BOOKMARK },
+        { type: TYPE_BOOKMARK },
+      ],
+      folderB: [],
+    },
+    targetFolder: "a",
+    targetIndex: 2,
+    expected: {
+      folderA: [
+        { folder: "a", originalIndex: 1 },
+        { folder: "a", originalIndex: 0 },
+        { folder: "a", originalIndex: 2 },
+      ],
+      folderB: [],
+    },
+    notifications: [
+      {
+        originalFolder: "folderA",
+        originalIndex: 0,
+        newFolder: "folderA",
+        newIndex: 1,
+      },
+    ],
+  });
+});
+
+add_task(
+  async function test_move_insert_multiple_same_folder_split_locations() {
+    await testMoveToFolder({
+      initial: {
+        folderA: [
+          { type: TYPE_BOOKMARK, move: true },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK, move: true },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK, move: true },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK },
+          { type: TYPE_BOOKMARK, move: true },
+        ],
+        folderB: [],
+      },
+      targetFolder: "a",
+      targetIndex: 2,
+      expected: {
+        folderA: [
+          { folder: "a", originalIndex: 1 },
+          { folder: "a", originalIndex: 0 },
+          { folder: "a", originalIndex: 3 },
+          { folder: "a", originalIndex: 6 },
+          { folder: "a", originalIndex: 9 },
+          { folder: "a", originalIndex: 2 },
+          { folder: "a", originalIndex: 4 },
+          { folder: "a", originalIndex: 5 },
+          { folder: "a", originalIndex: 7 },
+          { folder: "a", originalIndex: 8 },
+        ],
+        folderB: [],
+      },
+      notifications: [
+        {
+          originalFolder: "folderA",
+          originalIndex: 0,
+          newFolder: "folderA",
+          newIndex: 1,
+        },
+        {
+          originalFolder: "folderA",
+          originalIndex: 3,
+          newFolder: "folderA",
+          newIndex: 2,
+        },
+        {
+          originalFolder: "folderA",
+          originalIndex: 6,
+          newFolder: "folderA",
+          newIndex: 3,
+        },
+        {
+          originalFolder: "folderA",
+          originalIndex: 9,
+          newFolder: "folderA",
+          newIndex: 4,
+        },
+      ],
+    });
+  }
+);
+
+add_task(async function test_move_folder_with_descendant() {
+  let parent = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    url: "http://example.com/",
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+  });
+  let descendant = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  Assert.equal(descendant.index, 1);
+  let lastModified = bm.lastModified;
+
+  // This is moving to a nonexisting index by purpose, it will be appended.
+  [bm] = await PlacesUtils.bookmarks.moveToFolder(
+    [bm.guid],
+    descendant.guid,
+    1
+  );
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, descendant.guid);
+  Assert.equal(bm.index, 0);
+  Assert.ok(bm.lastModified >= lastModified);
+
+  parent = await PlacesUtils.bookmarks.fetch(parent.guid);
+  descendant = await PlacesUtils.bookmarks.fetch(descendant.guid);
+  Assert.deepEqual(parent.lastModified, bm.lastModified);
+  Assert.deepEqual(descendant.lastModified, bm.lastModified);
+  Assert.equal(descendant.index, 0);
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.equal(bm.parentGuid, descendant.guid);
+  Assert.equal(bm.index, 0);
+
+  [bm] = await PlacesUtils.bookmarks.moveToFolder([bm.guid], parent.guid, 0);
+  Assert.equal(bm.parentGuid, parent.guid);
+  Assert.equal(bm.index, 0);
+
+  descendant = await PlacesUtils.bookmarks.fetch(descendant.guid);
+  Assert.equal(descendant.index, 1);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js
new file mode 100644
index 0000000000..93f74c0055
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_notifications.js
@@ -0,0 +1,1184 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+ChromeUtils.defineESModuleGetters(this, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+add_task(async function insert_separator_notification() {
+  let observer = expectPlacesObserverNotifications(["bookmark-added"]);
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: itemId,
+      itemType: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      title: bm.title,
+      dateAdded: bm.dateAdded,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function insert_folder_notification() {
+  let observer = expectPlacesObserverNotifications(["bookmark-added"]);
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "a folder",
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: itemId,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      title: bm.title,
+      dateAdded: bm.dateAdded,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function insert_folder_notitle_notification() {
+  let observer = expectPlacesObserverNotifications(["bookmark-added"]);
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  strictEqual(bm.title, "", "Should return empty string for untitled folder");
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: itemId,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      title: bm.title,
+      dateAdded: bm.dateAdded,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function insert_bookmark_notification() {
+  let observer = expectPlacesObserverNotifications(["bookmark-added"]);
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://example.com/"),
+    title: "a bookmark",
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: itemId,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      title: bm.title,
+      dateAdded: bm.dateAdded,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function insert_bookmark_notitle_notification() {
+  let observer = expectPlacesObserverNotifications(["bookmark-added"]);
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://example.com/"),
+  });
+  strictEqual(bm.title, "", "Should return empty string for untitled bookmark");
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: itemId,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      title: bm.title,
+      dateAdded: bm.dateAdded,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function insert_bookmark_tag_notification() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://tag.example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  let tagFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "tag",
+  });
+  const observer = expectPlacesObserverNotifications([
+    "bookmark-added",
+    "bookmark-tags-changed",
+  ]);
+  let tag = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: tagFolder.guid,
+    url: new URL("http://tag.example.com/"),
+  });
+  let tagId = await PlacesTestUtils.promiseItemId(tag.guid);
+  let tagParentId = await PlacesTestUtils.promiseItemId(tag.parentGuid);
+
+  observer.check([
+    {
+      type: "bookmark-added",
+      id: tagId,
+      parentId: tagParentId,
+      index: tag.index,
+      itemType: tag.type,
+      url: tag.url,
+      title: "",
+      dateAdded: tag.dateAdded,
+      guid: tag.guid,
+      parentGuid: tag.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: true,
+    },
+    {
+      type: "bookmark-tags-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      tags: ["tag"],
+      lastModified: bm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function update_bookmark_lastModified() {
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://lastmod.example.com/"),
+  });
+  const observer = expectPlacesObserverNotifications(["bookmark-time-changed"]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    lastModified: new Date(),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  observer.check([
+    {
+      type: "bookmark-time-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      dateAdded: bm.dateAdded,
+      lastModified: bm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function update_bookmark_title() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://title.example.com/"),
+  });
+  const observer = expectPlacesObserverNotifications([
+    "bookmark-title-changed",
+  ]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    title: "new title",
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  observer.check([
+    {
+      type: "bookmark-title-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url,
+      title: bm.title,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      lastModified: bm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function update_bookmark_uri() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://url.example.com/"),
+  });
+  const observer = expectPlacesObserverNotifications(["bookmark-url-changed"]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    url: "http://mozilla.org/",
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  observer.check([
+    {
+      type: "bookmark-url-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url.href,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+      lastModified: bm.lastModified,
+    },
+  ]);
+});
+
+add_task(async function update_move_same_folder() {
+  // Ensure there are at least two items in place (others test do so for us,
+  // but we don't have to depend on that).
+  await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  const dateAdded = new Date();
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://move.example.com/"),
+    dateAdded,
+  });
+  let bmItemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let bmOldIndex = bm.index;
+
+  let observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 0,
+  });
+  Assert.equal(bm.index, 0);
+  observer.check([
+    {
+      type: "bookmark-moved",
+      id: bmItemId,
+      itemType: bm.type,
+      url: "http://move.example.com/",
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      index: bm.index,
+      oldParentGuid: bm.parentGuid,
+      oldIndex: bmOldIndex,
+      isTagging: false,
+      title: bm.title,
+      tags: "",
+      frecency: 1,
+      hidden: false,
+      visitCount: 0,
+      dateAdded: dateAdded.getTime(),
+      lastVisitDate: null,
+    },
+  ]);
+
+  // Test that we get the right index for DEFAULT_INDEX input.
+  bmOldIndex = 0;
+  observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  Assert.ok(bm.index > 0);
+  observer.check([
+    {
+      type: "bookmark-moved",
+      id: bmItemId,
+      itemType: bm.type,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      index: bm.index,
+      oldParentGuid: bm.parentGuid,
+      oldIndex: bmOldIndex,
+      isTagging: false,
+      title: bm.title,
+      tags: "",
+      frecency: 1,
+      hidden: false,
+      visitCount: 0,
+      dateAdded: dateAdded.getTime(),
+      lastVisitDate: null,
+    },
+  ]);
+});
+
+add_task(async function update_move_different_folder() {
+  const dateAdded = new Date();
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://move.example.com/"),
+    dateAdded,
+  });
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let bmItemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let bmOldIndex = bm.index;
+
+  const observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: folder.guid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  Assert.equal(bm.index, 0);
+  observer.check([
+    {
+      type: "bookmark-moved",
+      id: bmItemId,
+      itemType: bm.type,
+      url: "http://move.example.com/",
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      index: bm.index,
+      oldParentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      oldIndex: bmOldIndex,
+      isTagging: false,
+      title: bm.title,
+      tags: "",
+      frecency: 1,
+      hidden: false,
+      visitCount: 0,
+      dateAdded: dateAdded.getTime(),
+      lastVisitDate: null,
+    },
+  ]);
+});
+
+add_task(async function update_move_tag_folder() {
+  const dateAdded = new Date();
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://move.example.com/"),
+    dateAdded,
+  });
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "tag",
+  });
+  let bmItemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let bmOldIndex = bm.index;
+
+  const observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: folder.guid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  Assert.equal(bm.index, 0);
+  observer.check([
+    {
+      type: "bookmark-moved",
+      id: bmItemId,
+      itemType: bm.type,
+      url: "http://move.example.com/",
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      index: bm.index,
+      oldParentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      oldIndex: bmOldIndex,
+      isTagging: true,
+      title: bm.title,
+      tags: "tag",
+      frecency: 1,
+      hidden: false,
+      visitCount: 0,
+      dateAdded: dateAdded.getTime(),
+      lastVisitDate: null,
+    },
+  ]);
+});
+
+add_task(async function remove_bookmark() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://remove.example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.remove(bm.guid);
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: itemId,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function remove_multiple_bookmarks() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://remove.example.com/",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://remove1.example.com/",
+  });
+  let itemId1 = await PlacesTestUtils.promiseItemId(bm1.guid);
+  let parentId1 = await PlacesTestUtils.promiseItemId(bm1.parentGuid);
+  let itemId2 = await PlacesTestUtils.promiseItemId(bm2.guid);
+  let parentId2 = await PlacesTestUtils.promiseItemId(bm2.parentGuid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.remove([bm1, bm2]);
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: itemId1,
+      parentId: parentId1,
+      index: bm1.index,
+      url: bm1.url,
+      guid: bm1.guid,
+      parentGuid: bm1.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: itemId2,
+      parentId: parentId2,
+      index: bm2.index - 1,
+      url: bm2.url,
+      guid: bm2.guid,
+      parentGuid: bm2.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function remove_folder() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.remove(bm.guid);
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: itemId,
+      parentId,
+      index: bm.index,
+      url: null,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function remove_bookmark_tag_notification() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://untag.example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  let tagFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "tag",
+  });
+  let tag = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: tagFolder.guid,
+    url: new URL("http://untag.example.com/"),
+  });
+  let tagId = await PlacesTestUtils.promiseItemId(tag.guid);
+  let tagParentId = await PlacesTestUtils.promiseItemId(tag.parentGuid);
+
+  const observer = expectPlacesObserverNotifications([
+    "bookmark-removed",
+    "bookmark-tags-changed",
+  ]);
+  await PlacesUtils.bookmarks.remove(tag.guid);
+
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: tagId,
+      parentId: tagParentId,
+      index: tag.index,
+      url: tag.url,
+      guid: tag.guid,
+      parentGuid: tag.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: true,
+    },
+    {
+      type: "bookmark-tags-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      tags: [],
+      lastModified: bm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function rename_bookmark_tag_notification() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL("http://renametag.example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  let tagFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "tag",
+  });
+  let tag = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: tagFolder.guid,
+    url: new URL("http://renametag.example.com/"),
+  });
+  let tagParentId = await PlacesTestUtils.promiseItemId(tag.parentGuid);
+
+  const observer = expectPlacesObserverNotifications([
+    "bookmark-title-changed",
+    "bookmark-tags-changed",
+  ]);
+  tagFolder = await PlacesUtils.bookmarks.update({
+    guid: tagFolder.guid,
+    title: "renamed",
+  });
+
+  observer.check([
+    {
+      type: "bookmark-title-changed",
+      id: tagParentId,
+      title: "renamed",
+      guid: tagFolder.guid,
+      url: "",
+      lastModified: tagFolder.lastModified,
+      parentGuid: tagFolder.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: true,
+    },
+    {
+      type: "bookmark-tags-changed",
+      id: itemId,
+      itemType: bm.type,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      tags: ["renamed"],
+      lastModified: bm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function remove_folder_notification() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let folder1Id = await PlacesTestUtils.promiseItemId(folder1.guid);
+  let folder1ParentId = await PlacesTestUtils.promiseItemId(folder1.parentGuid);
+
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: folder1.guid,
+    url: new URL("http://example.com/"),
+  });
+  let bmItemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: folder1.guid,
+  });
+  let folder2Id = await PlacesTestUtils.promiseItemId(folder2.guid);
+
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: folder2.guid,
+    url: new URL("http://example.com/"),
+  });
+  let bm2ItemId = await PlacesTestUtils.promiseItemId(bm2.guid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.remove(folder1.guid);
+
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: bm2ItemId,
+      parentId: folder2Id,
+      index: bm2.index,
+      url: bm2.url,
+      guid: bm2.guid,
+      parentGuid: bm2.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder2Id,
+      parentId: folder1Id,
+      index: folder2.index,
+      url: null,
+      guid: folder2.guid,
+      parentGuid: folder2.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: bmItemId,
+      parentId: folder1Id,
+      index: bm.index,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder1Id,
+      parentId: folder1ParentId,
+      index: folder1.index,
+      url: null,
+      guid: folder1.guid,
+      parentGuid: folder1.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function multiple_tags() {
+  const BOOKMARK_URL = "http://multipletags.example.com/";
+  const TAG_NAMES = ["tag1", "tag2", "tag3", "tag4", "tag5", "tag6"];
+
+  const bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: new URL(BOOKMARK_URL),
+  });
+  const itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  info("Register all tags");
+  const tagFolders = await Promise.all(
+    TAG_NAMES.map(tagName =>
+      PlacesUtils.bookmarks.insert({
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        parentGuid: PlacesUtils.bookmarks.tagsGuid,
+        title: tagName,
+      })
+    )
+  );
+
+  info("Test adding tags to bookmark");
+  for (let i = 0; i < tagFolders.length; i++) {
+    const tagFolder = tagFolders[i];
+    const expectedTagNames = TAG_NAMES.slice(0, i + 1);
+
+    const observer = expectPlacesObserverNotifications([
+      "bookmark-tags-changed",
+    ]);
+
+    await PlacesUtils.bookmarks.insert({
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      parentGuid: tagFolder.guid,
+      url: new URL(BOOKMARK_URL),
+    });
+
+    observer.check([
+      {
+        type: "bookmark-tags-changed",
+        id: itemId,
+        itemType: bm.type,
+        url: bm.url,
+        guid: bm.guid,
+        parentGuid: bm.parentGuid,
+        tags: expectedTagNames,
+        lastModified: bm.lastModified,
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+    ]);
+  }
+
+  info("Test removing tags from bookmark");
+  for (const removedLength of [1, 2, 3]) {
+    const removedTags = tagFolders.splice(0, removedLength);
+
+    const observer = expectPlacesObserverNotifications([
+      "bookmark-tags-changed",
+    ]);
+
+    // We can remove multiple tags at one time.
+    await PlacesUtils.bookmarks.remove(removedTags);
+
+    const expectedResults = [];
+
+    for (let i = 0; i < removedLength; i++) {
+      TAG_NAMES.splice(0, 1);
+      const expectedTagNames = [...TAG_NAMES];
+
+      expectedResults.push({
+        type: "bookmark-tags-changed",
+        id: itemId,
+        itemType: bm.type,
+        url: bm.url,
+        guid: bm.guid,
+        parentGuid: bm.parentGuid,
+        tags: expectedTagNames,
+        lastModified: bm.lastModified,
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      });
+    }
+
+    observer.check(expectedResults);
+  }
+});
+
+add_task(async function eraseEverything_notification() {
+  // Let's start from a clean situation.
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let folder1Id = await PlacesTestUtils.promiseItemId(folder1.guid);
+  let folder1ParentId = await PlacesTestUtils.promiseItemId(folder1.parentGuid);
+
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: folder1.guid,
+    url: new URL("http://example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let folder2Id = await PlacesTestUtils.promiseItemId(folder2.guid);
+  let folder2ParentId = await PlacesTestUtils.promiseItemId(folder2.parentGuid);
+
+  let toolbarBm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: new URL("http://example.com/"),
+  });
+  let toolbarBmId = await PlacesTestUtils.promiseItemId(toolbarBm.guid);
+  let toolbarBmParentId = await PlacesTestUtils.promiseItemId(
+    toolbarBm.parentGuid
+  );
+
+  let menuBm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: new URL("http://example.com/"),
+  });
+  let menuBmId = await PlacesTestUtils.promiseItemId(menuBm.guid);
+  let menuBmParentId = await PlacesTestUtils.promiseItemId(menuBm.parentGuid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Bookmarks should always be notified before their parents.
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: itemId,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder2Id,
+      parentId: folder2ParentId,
+      index: folder2.index,
+      url: null,
+      guid: folder2.guid,
+      parentGuid: folder2.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder1Id,
+      parentId: folder1ParentId,
+      index: folder1.index,
+      url: null,
+      guid: folder1.guid,
+      parentGuid: folder1.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: menuBmId,
+      parentId: menuBmParentId,
+      index: menuBm.index,
+      url: menuBm.url,
+      guid: menuBm.guid,
+      parentGuid: menuBm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: toolbarBmId,
+      parentId: toolbarBmParentId,
+      index: toolbarBm.index,
+      url: toolbarBm.url,
+      guid: toolbarBm.guid,
+      parentGuid: toolbarBm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function eraseEverything_reparented_notification() {
+  // Let's start from a clean situation.
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let folder1Id = await PlacesTestUtils.promiseItemId(folder1.guid);
+  let folder1ParentId = await PlacesTestUtils.promiseItemId(folder1.parentGuid);
+
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: folder1.guid,
+    url: new URL("http://example.com/"),
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bm.guid);
+
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let folder2Id = await PlacesTestUtils.promiseItemId(folder2.guid);
+  let folder2ParentId = await PlacesTestUtils.promiseItemId(folder2.parentGuid);
+
+  bm.parentGuid = folder2.guid;
+  bm = await PlacesUtils.bookmarks.update(bm);
+  let parentId = await PlacesTestUtils.promiseItemId(bm.parentGuid);
+
+  let observer = expectPlacesObserverNotifications(["bookmark-removed"]);
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Bookmarks should always be notified before their parents.
+  observer.check([
+    {
+      type: "bookmark-removed",
+      id: itemId,
+      parentId,
+      index: bm.index,
+      url: bm.url,
+      guid: bm.guid,
+      parentGuid: bm.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder2Id,
+      parentId: folder2ParentId,
+      index: folder2.index,
+      url: null,
+      guid: folder2.guid,
+      parentGuid: folder2.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-removed",
+      id: folder1Id,
+      parentId: folder1ParentId,
+      index: folder1.index,
+      url: null,
+      guid: folder1.guid,
+      parentGuid: folder1.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      isTagging: false,
+    },
+  ]);
+});
+
+add_task(async function reorder_notification() {
+  const dateAdded = new Date();
+  let bookmarks = [
+    {
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      url: "http://example1.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      url: "http://example2.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      url: "http://example3.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded,
+    },
+  ];
+  let sorted = [];
+  for (let bm of bookmarks) {
+    sorted.push(await PlacesUtils.bookmarks.insert(bm));
+  }
+
+  // Randomly reorder the array.
+  sorted.sort(() => 0.5 - Math.random());
+  // Ensure there's at least one item out of place, since random does not
+  // necessarily mean they are unordered.
+  if (sorted[0].url == bookmarks[0].url) {
+    sorted.push(sorted.shift());
+  }
+
+  const observer = expectPlacesObserverNotifications(["bookmark-moved"]);
+  await PlacesUtils.bookmarks.reorder(
+    PlacesUtils.bookmarks.unfiledGuid,
+    sorted.map(bm => bm.guid)
+  );
+
+  let expectedNotifications = [];
+  for (let i = 0; i < sorted.length; ++i) {
+    let child = sorted[i];
+    let childId = await PlacesTestUtils.promiseItemId(child.guid);
+    expectedNotifications.push({
+      type: "bookmark-moved",
+      id: childId,
+      itemType: child.type,
+      url: child.url || "",
+      guid: child.guid,
+      parentGuid: child.parentGuid,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      index: i,
+      oldParentGuid: child.parentGuid,
+      oldIndex: child.index,
+      isTagging: false,
+      title: child.title,
+      tags: "",
+      frecency: child.url ? 1 : 0,
+      hidden: false,
+      visitCount: 0,
+      dateAdded: dateAdded.getTime(),
+      lastVisitDate: null,
+    });
+  }
+
+  observer.check(expectedNotifications);
+});
+
+add_task(async function update_notitle_notification() {
+  let toolbarBmURI = Services.io.newURI("https://example.com");
+  let toolbarItemId = await PlacesTestUtils.promiseItemId(
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+  let toolbarBmId = PlacesUtils.bookmarks.insertBookmark(
+    toolbarItemId,
+    toolbarBmURI,
+    0,
+    "Bookmark"
+  );
+  let toolbarBmGuid = await PlacesTestUtils.promiseItemGuid(toolbarBmId);
+
+  let menuFolder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    index: 0,
+    title: "Folder",
+  });
+  let menuFolderId = await PlacesTestUtils.promiseItemId(menuFolder.guid);
+
+  const observer = expectPlacesObserverNotifications([
+    "bookmark-title-changed",
+  ]);
+
+  PlacesUtils.bookmarks.setItemTitle(toolbarBmId, null);
+  strictEqual(
+    PlacesUtils.bookmarks.getItemTitle(toolbarBmId),
+    "",
+    "Legacy API should return empty string for untitled bookmark"
+  );
+
+  let updatedMenuBm = await PlacesUtils.bookmarks.update({
+    guid: menuFolder.guid,
+    title: null,
+  });
+  strictEqual(
+    updatedMenuBm.title,
+    "",
+    "Async API should return empty string for untitled bookmark"
+  );
+
+  let toolbarBmModified = await PlacesUtils.bookmarks.fetch(toolbarBmGuid);
+  observer.check([
+    {
+      type: "bookmark-title-changed",
+      id: toolbarBmId,
+      itemType: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      url: toolbarBmURI.spec,
+      title: "",
+      guid: toolbarBmGuid,
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      lastModified: toolbarBmModified.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-title-changed",
+      id: menuFolderId,
+      itemType: PlacesUtils.bookmarks.TYPE_FOLDER,
+      url: "",
+      title: "",
+      guid: menuFolder.guid,
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      lastModified: updatedMenuBm.lastModified,
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js
new file mode 100644
index 0000000000..01bb591e3c
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove.js
@@ -0,0 +1,465 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const UNVISITED_BOOKMARK_BONUS = 140;
+
+function promiseRankingChanged() {
+  return PlacesTestUtils.waitForNotification("pages-rank-changed");
+}
+
+add_task(async function setup() {
+  Services.prefs.setIntPref(
+    "places.frecency.unvisitedBookmarkBonus",
+    UNVISITED_BOOKMARK_BONUS
+  );
+});
+
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove(),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove(null),
+    /Input should be a valid object/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove("test"),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove(123),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ guid: "test" }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ guid: null }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ guid: 123 }),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ parentGuid: "test" }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ parentGuid: null }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ parentGuid: 123 }),
+    /Invalid value for property 'parentGuid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ url: "http://te st/" }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ url: null }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.remove({ url: -10 }),
+    /Invalid value for property 'url'/
+  );
+});
+
+add_task(async function remove_nonexistent_guid() {
+  try {
+    await PlacesUtils.bookmarks.remove({ guid: "123456789012" });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/No bookmarks found for the provided GUID/.test(ex));
+  }
+});
+
+add_task(async function remove_roots_fail() {
+  let guids = [
+    PlacesUtils.bookmarks.rootGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.tagsGuid,
+    PlacesUtils.bookmarks.mobileGuid,
+  ];
+  for (let guid of guids) {
+    Assert.throws(
+      () => PlacesUtils.bookmarks.remove(guid),
+      /It's not possible to remove Places root folders\./
+    );
+  }
+});
+
+add_task(async function remove_bookmark() {
+  // When removing a bookmark we need to check the frecency. First we confirm
+  // that there is a normal update when it is inserted.
+  let promise = promiseRankingChanged();
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+
+  // This second one checks the frecency is changed when we remove the bookmark.
+  promise = promiseRankingChanged();
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+});
+
+add_task(async function remove_multiple_bookmarks_simple() {
+  // When removing a bookmark we need to check the frecency. First we confirm
+  // that there is a normal update when it is inserted.
+  const promise1 = promiseRankingChanged();
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  const promise2 = promiseRankingChanged();
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example1.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm2);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await Promise.all([promise1, promise2]);
+
+  // We should get a pages-rank-changed event with the removal of
+  // multiple bookmarks.
+  const promise3 = promiseRankingChanged();
+
+  await PlacesUtils.bookmarks.remove([bm1, bm2]);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise3;
+});
+
+add_task(async function remove_multiple_bookmarks_complex() {
+  let bms = [];
+  for (let i = 0; i < 10; i++) {
+    bms.push(
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: `http://example.com/${i}`,
+        title: `bookmark ${i}`,
+      })
+    );
+  }
+
+  // Remove bookmarks 2 and 3.
+  let bmsToRemove = bms.slice(2, 4);
+  let notifiedIndexes = [];
+  let notificationPromise = PlacesTestUtils.waitForNotification(
+    "bookmark-removed",
+    events => {
+      for (let event of events) {
+        notifiedIndexes.push({ guid: event.guid, index: event.index });
+      }
+      return notifiedIndexes.length == bmsToRemove.length;
+    }
+  );
+  await PlacesUtils.bookmarks.remove(bmsToRemove);
+  await notificationPromise;
+
+  let indexModifier = 0;
+  for (let i = 0; i < bmsToRemove.length; i++) {
+    Assert.equal(
+      notifiedIndexes[i].guid,
+      bmsToRemove[i].guid,
+      `Should have been notified of the correct guid for item ${i}`
+    );
+    Assert.equal(
+      notifiedIndexes[i].index,
+      bmsToRemove[i].index - indexModifier,
+      `Should have been notified of the correct index for the item ${i}`
+    );
+    indexModifier++;
+  }
+
+  let expectedIndex = 0;
+  for (let bm of [bms[0], bms[1], ...bms.slice(4)]) {
+    const fetched = await PlacesUtils.bookmarks.fetch(bm.guid);
+    Assert.equal(
+      fetched.index,
+      expectedIndex,
+      "Should have the correct index after consecutive item removal"
+    );
+    bm.index = fetched.index;
+    expectedIndex++;
+  }
+
+  // Remove some more including non-consecutive.
+  bmsToRemove = [bms[1], bms[5], bms[6], bms[8]];
+  notifiedIndexes = [];
+  notificationPromise = PlacesTestUtils.waitForNotification(
+    "bookmark-removed",
+    events => {
+      for (let event of events) {
+        notifiedIndexes.push({ guid: event.guid, index: event.index });
+      }
+      return notifiedIndexes.length == bmsToRemove.length;
+    }
+  );
+  await PlacesUtils.bookmarks.remove(bmsToRemove);
+  await notificationPromise;
+
+  indexModifier = 0;
+  for (let i = 0; i < bmsToRemove.length; i++) {
+    Assert.equal(
+      notifiedIndexes[i].guid,
+      bmsToRemove[i].guid,
+      `Should have been notified of the correct guid for item ${i}`
+    );
+    Assert.equal(
+      notifiedIndexes[i].index,
+      bmsToRemove[i].index - indexModifier,
+      `Should have been notified of the correct index for the item ${i}`
+    );
+    indexModifier++;
+  }
+
+  expectedIndex = 0;
+  const expectedRemaining = [bms[0], bms[4], bms[7], bms[9]];
+  for (let bm of expectedRemaining) {
+    const fetched = await PlacesUtils.bookmarks.fetch(bm.guid);
+    Assert.equal(
+      fetched.index,
+      expectedIndex,
+      "Should have the correct index after non-consecutive item removal"
+    );
+    expectedIndex++;
+  }
+
+  // Tidy up
+  await PlacesUtils.bookmarks.remove(expectedRemaining);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function remove_bookmark_empty_title() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "",
+  });
+  checkBookmarkObject(bm1);
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+});
+
+add_task(async function remove_folder() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  checkBookmarkObject(bm1);
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+
+  // No wait for pages-rank-changed event in this test as the folder doesn't have
+  // any children that would need updating.
+});
+
+add_task(async function test_contents_removed() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "",
+  });
+
+  let skipDescendantsObserver = expectPlacesObserverNotifications(
+    ["bookmark-removed"],
+    false,
+    true
+  );
+  let receiveAllObserver = expectPlacesObserverNotifications(
+    ["bookmark-removed"],
+    false,
+    false
+  );
+  const promise = promiseRankingChanged();
+  await PlacesUtils.bookmarks.remove(folder1);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(folder1.guid), null);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+
+  let expectedNotifications = [
+    {
+      type: "bookmark-removed",
+      guid: folder1.guid,
+    },
+  ];
+
+  // If we're skipping descendents, we'll only be notified of the folder.
+  skipDescendantsObserver.check(expectedNotifications);
+
+  // Note: Items of folders get notified first.
+  expectedNotifications.unshift({
+    type: "bookmark-removed",
+    guid: bm1.guid,
+  });
+  // If we don't skip descendents, we'll be notified of the folder and the
+  // bookmark.
+  receiveAllObserver.check(expectedNotifications);
+});
+
+add_task(async function test_nested_contents_removed() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  let folder2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder2.guid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "",
+  });
+
+  const promise = promiseRankingChanged();
+  await PlacesUtils.bookmarks.remove(folder1);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(folder1.guid), null);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(folder2.guid), null);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+});
+
+add_task(async function remove_folder_empty_title() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "",
+  });
+  checkBookmarkObject(bm1);
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+});
+
+add_task(async function remove_separator() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  checkBookmarkObject(bm1);
+
+  await PlacesUtils.bookmarks.remove(bm1.guid);
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(bm1.guid), null);
+});
+
+add_task(async function test_nested_content_fails_when_not_allowed() {
+  let folder1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: folder1.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+  await Assert.rejects(
+    PlacesUtils.bookmarks.remove(folder1, {
+      preventRemovalOfNonEmptyFolders: true,
+    }),
+    /Cannot remove a non-empty folder./
+  );
+});
+
+add_task(async function test_remove_bookmark_with_invalid_url() {
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "folder",
+  });
+  let guid = "invalid_____";
+  let folderedGuid = "invalid____2";
+  let url = "invalid-uri";
+  await PlacesUtils.withConnectionWrapper("test_bookmarks_remove", async db => {
+    await db.execute(
+      `
+      INSERT INTO moz_places(url, url_hash, title, rev_host, guid)
+      VALUES (:url, hash(:url), 'Invalid URI', '.', GENERATE_GUID())
+    `,
+      { url }
+    );
+    await db.execute(
+      `INSERT INTO moz_bookmarks (type, fk, parent, position, guid)
+        VALUES (:type,
+                (SELECT id FROM moz_places WHERE url = :url),
+                (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+                (SELECT MAX(position) + 1 FROM moz_bookmarks WHERE parent = (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid)),
+                :guid)
+      `,
+      {
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        guid,
+      }
+    );
+    await db.execute(
+      `INSERT INTO moz_bookmarks (type, fk, parent, position, guid)
+        VALUES (:type,
+                (SELECT id FROM moz_places WHERE url = :url),
+                (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+                (SELECT MAX(position) + 1 FROM moz_bookmarks WHERE parent = (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid)),
+                :guid)
+      `,
+      {
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url,
+        parentGuid: folder.guid,
+        guid: folderedGuid,
+      }
+    );
+  });
+  await PlacesUtils.bookmarks.remove(guid);
+  Assert.strictEqual(
+    await PlacesUtils.bookmarks.fetch(guid),
+    null,
+    "Should not throw and not find the bookmark"
+  );
+
+  await PlacesUtils.bookmarks.remove(folder);
+  Assert.strictEqual(
+    await PlacesUtils.bookmarks.fetch(folderedGuid),
+    null,
+    "Should not throw and not find the bookmark"
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_remove_batch.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove_batch.js
new file mode 100644
index 0000000000..51a2a4dc2b
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_remove_batch.js
@@ -0,0 +1,129 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test whether do batch removal if multiple bookmarks are removed at once.
+
+add_task(async function test_remove_multiple_bookmarks() {
+  info("Test for remove multiple bookmarks at once");
+
+  info("Insert multiple bookmarks");
+  const testBookmarks = [
+    {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: "http://example.com/1",
+    },
+    {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: "http://example.com/2",
+    },
+    {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: "http://example.com/3",
+    },
+  ];
+  const bookmarks = await Promise.all(
+    testBookmarks.map(bookmark => PlacesUtils.bookmarks.insert(bookmark))
+  );
+  Assert.equal(
+    bookmarks.length,
+    testBookmarks.length,
+    "All test data are insterted correctly"
+  );
+
+  info("Remove multiple bookmarks");
+  const onRemoved = PlacesTestUtils.waitForNotification("bookmark-removed");
+  await PlacesUtils.bookmarks.remove(bookmarks);
+  const events = await onRemoved;
+
+  info("Check whether all bookmark-removed events called at at once or not");
+  assertBookmarkRemovedEvents(events, bookmarks);
+});
+
+add_task(async function test_remove_folder_with_bookmarks() {
+  info("Test for remove a folder that has multiple bookmarks");
+
+  info("Insert a folder");
+  const testFolder = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  };
+  const folder = await PlacesUtils.bookmarks.insert(testFolder);
+  Assert.ok(folder, "A folder is inserted correctly");
+
+  info("Insert multiple bookmarks to inserted folder");
+  const testBookmarks = [
+    {
+      parentGuid: folder.guid,
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      url: "http://example.com/1",
+    },
+    {
+      parentGuid: folder.guid,
+      url: "http://example.com/2",
+    },
+    {
+      parentGuid: folder.guid,
+      url: "http://example.com/3",
+    },
+  ];
+  const bookmarks = await Promise.all(
+    testBookmarks.map(bookmark => PlacesUtils.bookmarks.insert(bookmark))
+  );
+  Assert.equal(
+    bookmarks.length,
+    testBookmarks.length,
+    "All test data are insterted correctly"
+  );
+
+  info("Remove the inserted folder");
+  const notifiedEvents = [];
+  const onRemoved = PlacesTestUtils.waitForNotification(
+    "bookmark-removed",
+    events => {
+      notifiedEvents.push(events);
+      return notifiedEvents.length === 2;
+    }
+  );
+  await PlacesUtils.bookmarks.remove(folder);
+  await onRemoved;
+
+  info("Check whether all bookmark-removed events called at at once or not");
+  const eventsForBookmarks = notifiedEvents[0];
+  assertBookmarkRemovedEvents(eventsForBookmarks, bookmarks);
+
+  info("Check whether a bookmark-removed event called for the folder");
+  const eventsForFolder = notifiedEvents[1];
+  Assert.equal(
+    eventsForFolder.length,
+    1,
+    "The length of notified events is correct"
+  );
+  Assert.equal(
+    eventsForFolder[0].guid,
+    folder.guid,
+    "The guid of event is correct"
+  );
+});
+
+function assertBookmarkRemovedEvents(events, expectedBookmarks) {
+  Assert.equal(
+    events.length,
+    expectedBookmarks.length,
+    "The length of notified events is correct"
+  );
+
+  for (let i = 0; i < events.length; i++) {
+    const event = events[i];
+    const expectedBookmark = expectedBookmarks[i];
+    Assert.equal(
+      event.guid,
+      expectedBookmark.guid,
+      `The guid of events[${i}] is correct`
+    );
+    Assert.equal(
+      event.url,
+      expectedBookmark.url,
+      `The url of events[${i}] is correct`
+    );
+  }
+}
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_reorder.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_reorder.js
new file mode 100644
index 0000000000..7df909c704
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_reorder.js
@@ -0,0 +1,310 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder(),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder(null),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("test"),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder(123),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder({ guid: "test" }),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012"),
+    /Must provide a sorted array of children GUIDs./
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", {}),
+    /Must provide a sorted array of children GUIDs./
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", null),
+    /Must provide a sorted array of children GUIDs./
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", []),
+    /Must provide a sorted array of children GUIDs./
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", [null]),
+    /Invalid GUID found in the sorted children array/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", [""]),
+    /Invalid GUID found in the sorted children array/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", [{}]),
+    /Invalid GUID found in the sorted children array/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.reorder("123456789012", ["012345678901", null]),
+    /Invalid GUID found in the sorted children array/
+  );
+});
+
+add_task(async function reorder_nonexistent_guid() {
+  await Assert.rejects(
+    PlacesUtils.bookmarks.reorder("123456789012", ["012345678901"]),
+    /No folder found for the provided GUID/,
+    "Should throw for nonexisting guid"
+  );
+});
+
+add_task(async function reorder() {
+  let bookmarks = [
+    {
+      url: "http://example1.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      url: "http://example2.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      url: "http://example3.com/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+  ];
+
+  let sorted = [];
+  for (let bm of bookmarks) {
+    sorted.push(await PlacesUtils.bookmarks.insert(bm));
+  }
+
+  // Check the initial append sorting.
+  Assert.ok(
+    sorted.every((bm, i) => bm.index == i),
+    "Initial bookmarks sorting is correct"
+  );
+
+  // Apply random sorting and run multiple tests.
+  for (let t = 0; t < 4; t++) {
+    sorted.sort(() => 0.5 - Math.random());
+    let sortedGuids = sorted.map(child => child.guid);
+    dump("Expected order: " + sortedGuids.join() + "\n");
+    // Add a nonexisting guid to the array, to ensure nothing will break.
+    sortedGuids.push("123456789012");
+    await PlacesUtils.bookmarks.reorder(
+      PlacesUtils.bookmarks.unfiledGuid,
+      sortedGuids
+    );
+    for (let i = 0; i < sorted.length; ++i) {
+      let item = await PlacesUtils.bookmarks.fetch(sorted[i].guid);
+      Assert.equal(item.index, i);
+    }
+  }
+
+  info("Test partial sorting");
+  {
+    // Try a partial sorting by passing 2 entries in same order as they
+    // currently have. No entries should change order.
+    let sortedGuids = [sorted[0].guid, sorted[3].guid];
+    dump("Expected order: " + sorted.map(b => b.guid).join() + "\n");
+    await PlacesUtils.bookmarks.reorder(
+      PlacesUtils.bookmarks.unfiledGuid,
+      sortedGuids
+    );
+    for (let i = 0; i < sorted.length; ++i) {
+      let item = await PlacesUtils.bookmarks.fetch(sorted[i].guid);
+      Assert.equal(item.index, i);
+    }
+  }
+
+  {
+    // Try a partial sorting by passing 2 entries out of order
+    // The unspecified entries should be appended and retain the original order
+    sorted = [sorted[1], sorted[0]].concat(sorted.slice(2));
+    let sortedGuids = [sorted[0].guid, sorted[1].guid];
+    dump("Expected order: " + sorted.map(b => b.guid).join() + "\n");
+    await PlacesUtils.bookmarks.reorder(
+      PlacesUtils.bookmarks.unfiledGuid,
+      sortedGuids
+    );
+    for (let i = 0; i < sorted.length; ++i) {
+      let item = await PlacesUtils.bookmarks.fetch(sorted[i].guid);
+      Assert.equal(item.index, i);
+    }
+  }
+  // Use triangular numbers to detect skipped position.
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(
+    `SELECT parent
+     FROM moz_bookmarks
+     GROUP BY parent
+     HAVING (SUM(DISTINCT position + 1) - (count(*) * (count(*) + 1) / 2)) <> 0`
+  );
+  Assert.equal(
+    rows.length,
+    0,
+    "All the bookmarks should have consistent positions"
+  );
+});
+
+add_task(async function move_and_reorder() {
+  // Start clean.
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    url: "http://example1.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let f1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    url: "http://example2.com/",
+    parentGuid: f1.guid,
+  });
+  let f2 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    url: "http://example3.com/",
+    parentGuid: f2.guid,
+  });
+  let bm4 = await PlacesUtils.bookmarks.insert({
+    url: "http://example4.com/",
+    parentGuid: f2.guid,
+  });
+  let bm5 = await PlacesUtils.bookmarks.insert({
+    url: "http://example5.com/",
+    parentGuid: f2.guid,
+  });
+
+  // Invert f2 children.
+  // This is critical to reproduce the bug, cause it inverts the position
+  // compared to the natural insertion order.
+  await PlacesUtils.bookmarks.reorder(f2.guid, [bm5.guid, bm4.guid, bm3.guid]);
+
+  bm1.parentGuid = f1.guid;
+  bm1.index = 0;
+  await PlacesUtils.bookmarks.update(bm1);
+
+  bm1 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  Assert.equal(bm1.index, 0);
+  bm2 = await PlacesUtils.bookmarks.fetch(bm2.guid);
+  Assert.equal(bm2.index, 1);
+  bm3 = await PlacesUtils.bookmarks.fetch(bm3.guid);
+  Assert.equal(bm3.index, 2);
+  bm4 = await PlacesUtils.bookmarks.fetch(bm4.guid);
+  Assert.equal(bm4.index, 1);
+  bm5 = await PlacesUtils.bookmarks.fetch(bm5.guid);
+  Assert.equal(bm5.index, 0);
+
+  // No-op reorder on f1 children.
+  // Nothing should change. Though, due to bug 1293365 this was causing children
+  // of other folders to get messed up.
+  await PlacesUtils.bookmarks.reorder(f1.guid, [bm1.guid, bm2.guid]);
+
+  bm1 = await PlacesUtils.bookmarks.fetch(bm1.guid);
+  Assert.equal(bm1.index, 0);
+  bm2 = await PlacesUtils.bookmarks.fetch(bm2.guid);
+  Assert.equal(bm2.index, 1);
+  bm3 = await PlacesUtils.bookmarks.fetch(bm3.guid);
+  Assert.equal(bm3.index, 2);
+  bm4 = await PlacesUtils.bookmarks.fetch(bm4.guid);
+  Assert.equal(bm4.index, 1);
+  bm5 = await PlacesUtils.bookmarks.fetch(bm5.guid);
+  Assert.equal(bm5.index, 0);
+});
+
+add_task(async function reorder_empty_folder_invalid_children() {
+  // Start clean.
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let f1 = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  // Specifying a child that doesn't exist should cause that to be ignored.
+  // However, before bug 1333304, doing this on an empty folder threw.
+  await PlacesUtils.bookmarks.reorder(f1.guid, ["123456789012"]);
+});
+
+add_task(async function reorder_lastModified() {
+  // Start clean.
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let lastModified = new Date(Date.now() - 1000);
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+        dateAdded: lastModified,
+        lastModified,
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+        dateAdded: lastModified,
+        lastModified,
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    lastModified,
+  });
+
+  info("Reorder and set explicit last modified time");
+  let newLastModified = new Date(lastModified.getTime() + 500);
+  await PlacesUtils.bookmarks.reorder(
+    PlacesUtils.bookmarks.menuGuid,
+    ["bookmarkBBBB", "bookmarkAAAA"],
+    { lastModified: newLastModified }
+  );
+  for (let guid of [
+    PlacesUtils.bookmarks.menuGuid,
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]) {
+    let info = await PlacesUtils.bookmarks.fetch(guid);
+    Assert.equal(info.lastModified.getTime(), newLastModified.getTime());
+  }
+
+  info("Reorder and set default last modified time");
+  await PlacesUtils.bookmarks.reorder(PlacesUtils.bookmarks.menuGuid, [
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]);
+  for (let guid of [
+    PlacesUtils.bookmarks.menuGuid,
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]) {
+    let info = await PlacesUtils.bookmarks.fetch(guid);
+    Assert.greater(info.lastModified.getTime(), newLastModified.getTime());
+  }
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_search.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_search.js
new file mode 100644
index 0000000000..2b34b2c8f9
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_search.js
@@ -0,0 +1,339 @@
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search(),
+    /Query object is required/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search(null),
+    /Query object is required/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search({ title: 50 }),
+    /Title option must be a string/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search({ url: { url: "wombat" } }),
+    /Url option must be a string or a URL object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search(50),
+    /Query must be an object or a string/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.search(true),
+    /Query must be an object or a string/
+  );
+});
+
+add_task(async function search_bookmark() {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/",
+    title: "another bookmark",
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://menu.org/",
+    title: "an on-menu bookmark",
+  });
+  let bm4 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: "http://toolbar.org/",
+    title: "an on-toolbar bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+  checkBookmarkObject(bm3);
+  checkBookmarkObject(bm4);
+
+  // finds a result by query
+  let results = await PlacesUtils.bookmarks.search("example.com");
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm1, results[0]);
+
+  // finds multiple results
+  results = await PlacesUtils.bookmarks.search("example");
+  Assert.equal(results.length, 2);
+  checkBookmarkObject(results[0]);
+  checkBookmarkObject(results[1]);
+
+  // finds menu bookmarks
+  results = await PlacesUtils.bookmarks.search("an on-menu bookmark");
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm3, results[0]);
+
+  // finds toolbar bookmarks
+  results = await PlacesUtils.bookmarks.search("an on-toolbar bookmark");
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm4, results[0]);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_bookmark_by_query_object() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/",
+    title: "another bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+
+  let results = await PlacesUtils.bookmarks.search({ query: "example.com" });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+
+  Assert.deepEqual(bm1, results[0]);
+
+  results = await PlacesUtils.bookmarks.search({ query: "example" });
+  Assert.equal(results.length, 2);
+  checkBookmarkObject(results[0]);
+  checkBookmarkObject(results[1]);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_bookmark_by_url() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/path",
+    title: "another bookmark",
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/path",
+    title: "third bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+  checkBookmarkObject(bm3);
+
+  // finds the correct result by url
+  let results = await PlacesUtils.bookmarks.search({
+    url: "http://example.com/",
+  });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm1, results[0]);
+
+  // normalizes the url
+  results = await PlacesUtils.bookmarks.search({ url: "http:/example.com" });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm1, results[0]);
+
+  // returns multiple matches
+  results = await PlacesUtils.bookmarks.search({
+    url: "http://example.org/path",
+  });
+  Assert.equal(results.length, 2);
+
+  // requires exact match
+  results = await PlacesUtils.bookmarks.search({ url: "http://example.org/" });
+  Assert.equal(results.length, 0);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_bookmark_by_title() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/path",
+    title: "another bookmark",
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.net/",
+    title: "another bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+  checkBookmarkObject(bm3);
+
+  // finds the correct result by title
+  let results = await PlacesUtils.bookmarks.search({ title: "a bookmark" });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm1, results[0]);
+
+  // returns multiple matches
+  results = await PlacesUtils.bookmarks.search({ title: "another bookmark" });
+  Assert.equal(results.length, 2);
+
+  // requires exact match
+  results = await PlacesUtils.bookmarks.search({ title: "bookmark" });
+  Assert.equal(results.length, 0);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_bookmark_combinations() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.org/path",
+    title: "another bookmark",
+  });
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.net/",
+    title: "third bookmark",
+  });
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+  checkBookmarkObject(bm3);
+
+  // finds the correct result if title and url match
+  let results = await PlacesUtils.bookmarks.search({
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm1, results[0]);
+
+  // does not match if query is not matching but url and title match
+  results = await PlacesUtils.bookmarks.search({
+    url: "http://example.com/",
+    title: "a bookmark",
+    query: "nonexistent",
+  });
+  Assert.equal(results.length, 0);
+
+  // does not match if one parameter is not matching
+  results = await PlacesUtils.bookmarks.search({
+    url: "http://what.ever",
+    title: "a bookmark",
+  });
+  Assert.equal(results.length, 0);
+
+  // query only matches if other fields match as well
+  results = await PlacesUtils.bookmarks.search({
+    query: "bookmark",
+    url: "http://example.net/",
+  });
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm3, results[0]);
+
+  // non-matching query will also return no results
+  results = await PlacesUtils.bookmarks.search({
+    query: "nonexistent",
+    url: "http://example.net/",
+  });
+  Assert.equal(results.length, 0);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_folder() {
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a test folder",
+  });
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(folder);
+  checkBookmarkObject(bm);
+
+  // also finds folders
+  let results = await PlacesUtils.bookmarks.search("a test folder");
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.equal(folder.title, results[0].title);
+  Assert.equal(folder.type, results[0].type);
+  Assert.equal(folder.parentGuid, results[0].parentGuid);
+
+  // finds elements in folders
+  results = await PlacesUtils.bookmarks.search("example.com");
+  Assert.equal(results.length, 1);
+  checkBookmarkObject(results[0]);
+  Assert.deepEqual(bm, results[0]);
+  Assert.equal(folder.guid, results[0].parentGuid);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_includes_separators() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+
+  checkBookmarkObject(bm1);
+  checkBookmarkObject(bm2);
+
+  let results = await PlacesUtils.bookmarks.search({});
+  Assert.ok(
+    results.findIndex(bookmark => {
+      return bookmark.guid == bm1.guid;
+    }) > -1,
+    "The bookmark was found in the results."
+  );
+  Assert.ok(
+    results.findIndex(bookmark => {
+      return bookmark.guid == bm2.guid;
+    }) > -1,
+    "The separator was included in the results."
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function search_excludes_tags() {
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  checkBookmarkObject(bm1);
+  PlacesUtils.tagging.tagURI(bm1.url.URI, ["Test Tag"]);
+
+  let results = await PlacesUtils.bookmarks.search("example.com");
+  // If tags are not being excluded, this would return two results, one representing the tag.
+  Assert.equal(1, results.length, "A single object was returned from search.");
+  Assert.deepEqual(bm1, results[0], "The bookmark was returned.");
+
+  results = await PlacesUtils.bookmarks.search("Test Tag");
+  Assert.equal(0, results.length, "The tag folder was not returned.");
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js b/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js
new file mode 100644
index 0000000000..1c9bead831
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_bookmarks_update.js
@@ -0,0 +1,587 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function invalid_input_throws() {
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update(),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update(null),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({}),
+    /The following properties were expected/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ guid: "test" }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ guid: null }),
+    /Invalid value for property 'guid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ guid: 123 }),
+    /Invalid value for property 'guid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ parentGuid: "test" }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ parentGuid: null }),
+    /Invalid value for property 'parentGuid'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ parentGuid: 123 }),
+    /Invalid value for property 'parentGuid'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ index: "1" }),
+    /Invalid value for property 'index'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ index: -10 }),
+    /Invalid value for property 'index'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ dateAdded: -10 }),
+    /Invalid value for property 'dateAdded'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ dateAdded: "today" }),
+    /Invalid value for property 'dateAdded'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ dateAdded: Date.now() }),
+    /Invalid value for property 'dateAdded'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ lastModified: -10 }),
+    /Invalid value for property 'lastModified'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ lastModified: "today" }),
+    /Invalid value for property 'lastModified'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ lastModified: Date.now() }),
+    /Invalid value for property 'lastModified'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ type: -1 }),
+    /Invalid value for property 'type'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ type: 100 }),
+    /Invalid value for property 'type'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ type: "bookmark" }),
+    /Invalid value for property 'type'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ url: 10 }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ url: "http://te st" }),
+    /Invalid value for property 'url'/
+  );
+  let longurl = "http://www.example.com/";
+  for (let i = 0; i < 65536; i++) {
+    longurl += "a";
+  }
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ url: longurl }),
+    /Invalid value for property 'url'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ url: NetUtil.newURI(longurl) }),
+    /Invalid value for property 'url'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ url: "te st" }),
+    /Invalid value for property 'url'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ title: -1 }),
+    /Invalid value for property 'title'/
+  );
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ title: {} }),
+    /Invalid value for property 'title'/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.bookmarks.update({ guid: "123456789012" }),
+    /Not enough properties to update/
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.update({
+        guid: "123456789012",
+        parentGuid: "012345678901",
+      }),
+    /The following properties were expected: index/
+  );
+});
+
+add_task(async function move_roots_fail() {
+  let guids = [
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.tagsGuid,
+    PlacesUtils.bookmarks.mobileGuid,
+  ];
+  for (let guid of guids) {
+    await Assert.rejects(
+      PlacesUtils.bookmarks.update({
+        guid,
+        index: -1,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      }),
+      /It's not possible to move Places root folders\./,
+      `Should reject when attempting to move ${guid}`
+    );
+  }
+});
+
+add_task(async function nonexisting_bookmark_throws() {
+  try {
+    await PlacesUtils.bookmarks.update({ guid: "123456789012", title: "test" });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/No bookmarks found for the provided GUID/.test(ex));
+  }
+});
+
+add_task(async function invalid_properties_for_existing_bookmark() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+  });
+
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: bm.guid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/The bookmark type cannot be changed/.test(ex));
+  }
+
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: bm.guid,
+      parentGuid: "123456789012",
+      index: 1,
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/No bookmarks found for the provided parentGuid/.test(ex));
+  }
+
+  let past = new Date(Date.now() - 86400000);
+  try {
+    await PlacesUtils.bookmarks.update({ guid: bm.guid, lastModified: past });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/Invalid value for property 'lastModified'/.test(ex));
+  }
+
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: folder.guid,
+      url: "http://example.com/",
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/Invalid value for property 'url'/.test(ex));
+  }
+
+  let separator = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: separator.guid,
+      url: "http://example.com/",
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/Invalid value for property 'url'/.test(ex));
+  }
+  try {
+    await PlacesUtils.bookmarks.update({ guid: separator.guid, title: "test" });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(/Invalid value for property 'title'/.test(ex));
+  }
+});
+
+add_task(async function long_title_trim() {
+  let longtitle = "a";
+  for (let i = 0; i < 4096; i++) {
+    longtitle += "a";
+  }
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "title",
+  });
+  checkBookmarkObject(bm);
+
+  bm = await PlacesUtils.bookmarks.update({ guid: bm.guid, title: longtitle });
+  let newTitle = bm.title;
+  Assert.equal(newTitle.length, 4096, "title should have been trimmed");
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.equal(bm.title, newTitle);
+});
+
+add_task(async function update_lastModified() {
+  let yesterday = new Date(Date.now() - 86400000);
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "title",
+    dateAdded: yesterday,
+  });
+  checkBookmarkObject(bm);
+  Assert.deepEqual(bm.lastModified, yesterday);
+
+  let time = new Date();
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    lastModified: time,
+  });
+  checkBookmarkObject(bm);
+  Assert.deepEqual(bm.lastModified, time);
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.deepEqual(bm.lastModified, time);
+
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    lastModified: yesterday,
+  });
+  Assert.deepEqual(bm.lastModified, yesterday);
+
+  bm = await PlacesUtils.bookmarks.update({ guid: bm.guid, title: "title2" });
+  Assert.ok(bm.lastModified >= time);
+
+  bm = await PlacesUtils.bookmarks.update({ guid: bm.guid, title: "" });
+  Assert.strictEqual(bm.title, "");
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.strictEqual(bm.title, "");
+});
+
+add_task(async function update_url() {
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "http://example.com/",
+    title: "title",
+  });
+  checkBookmarkObject(bm);
+  let lastModified = bm.lastModified;
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  let frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url: bm.url }
+  );
+  Assert.greater(frecency, 0, "Check frecency has been updated");
+
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    url: "http://mozilla.org/",
+  });
+  checkBookmarkObject(bm);
+  Assert.ok(bm.lastModified >= lastModified);
+  Assert.equal(bm.url.href, "http://mozilla.org/");
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.equal(bm.url.href, "http://mozilla.org/");
+  Assert.ok(bm.lastModified >= lastModified);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://example.com/",
+    }),
+    frecency,
+    "Check frecency for example.com"
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: "http://mozilla.org/",
+    }),
+    frecency,
+    "Check frecency for mozilla.org"
+  );
+});
+
+add_task(async function update_index() {
+  let parent = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let f1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  Assert.equal(f1.index, 0);
+  let f2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  Assert.equal(f2.index, 1);
+  let f3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  Assert.equal(f3.index, 2);
+  let lastModified = f1.lastModified;
+
+  f1 = await PlacesUtils.bookmarks.update({
+    guid: f1.guid,
+    parentGuid: f1.parentGuid,
+    index: 1,
+  });
+  checkBookmarkObject(f1);
+  Assert.equal(f1.index, 1);
+  Assert.ok(f1.lastModified >= lastModified);
+
+  parent = await PlacesUtils.bookmarks.fetch(f1.parentGuid);
+  Assert.deepEqual(parent.lastModified, f1.lastModified);
+
+  f2 = await PlacesUtils.bookmarks.fetch(f2.guid);
+  Assert.equal(f2.index, 0);
+
+  f3 = await PlacesUtils.bookmarks.fetch(f3.guid);
+  Assert.equal(f3.index, 2);
+
+  f3 = await PlacesUtils.bookmarks.update({ guid: f3.guid, index: 0 });
+  f1 = await PlacesUtils.bookmarks.fetch(f1.guid);
+  Assert.equal(f1.index, 2);
+
+  f2 = await PlacesUtils.bookmarks.fetch(f2.guid);
+  Assert.equal(f2.index, 1);
+});
+
+add_task(async function update_move_folder_into_descendant_throws() {
+  let parent = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let descendant = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: parent.guid,
+      parentGuid: parent.guid,
+      index: 0,
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(
+      /Cannot insert a folder into itself or one of its descendants/.test(ex)
+    );
+  }
+
+  try {
+    await PlacesUtils.bookmarks.update({
+      guid: parent.guid,
+      parentGuid: descendant.guid,
+      index: 0,
+    });
+    Assert.ok(false, "Should have thrown");
+  } catch (ex) {
+    Assert.ok(
+      /Cannot insert a folder into itself or one of its descendants/.test(ex)
+    );
+  }
+});
+
+add_task(async function update_move_into_root_folder_rejects() {
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+  });
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.update({
+        guid: bm.guid,
+        index: -1,
+        parentGuid: PlacesUtils.bookmarks.rootGuid,
+      }),
+    /Invalid value for property 'parentGuid'/,
+    "Should reject when attempting to move a bookmark into the root"
+  );
+
+  Assert.throws(
+    () =>
+      PlacesUtils.bookmarks.update({
+        guid: folder.guid,
+        index: -1,
+        parentGuid: PlacesUtils.bookmarks.rootGuid,
+      }),
+    /Invalid value for property 'parentGuid'/,
+    "Should reject when attempting to move a bookmark into the root"
+  );
+});
+
+add_task(async function update_move() {
+  let parent = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    url: "http://example.com/",
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+  });
+  let descendant = await PlacesUtils.bookmarks.insert({
+    parentGuid: parent.guid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  Assert.equal(descendant.index, 1);
+  let lastModified = bm.lastModified;
+
+  // This is moving to a nonexisting index by purpose, it will be appended.
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: descendant.guid,
+    index: 1,
+  });
+  checkBookmarkObject(bm);
+  Assert.equal(bm.parentGuid, descendant.guid);
+  Assert.equal(bm.index, 0);
+  Assert.ok(bm.lastModified >= lastModified);
+
+  parent = await PlacesUtils.bookmarks.fetch(parent.guid);
+  descendant = await PlacesUtils.bookmarks.fetch(descendant.guid);
+  Assert.deepEqual(parent.lastModified, bm.lastModified);
+  Assert.deepEqual(descendant.lastModified, bm.lastModified);
+  Assert.equal(descendant.index, 0);
+
+  bm = await PlacesUtils.bookmarks.fetch(bm.guid);
+  Assert.equal(bm.parentGuid, descendant.guid);
+  Assert.equal(bm.index, 0);
+
+  bm = await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    parentGuid: parent.guid,
+    index: 0,
+  });
+  Assert.equal(bm.parentGuid, parent.guid);
+  Assert.equal(bm.index, 0);
+
+  descendant = await PlacesUtils.bookmarks.fetch(descendant.guid);
+  Assert.equal(descendant.index, 1);
+});
+
+add_task(async function update_move_append() {
+  let folder_a = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(folder_a);
+  let folder_b = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkBookmarkObject(folder_b);
+
+  /* folder_a: [sep_1, sep_2, sep_3], folder_b: [] */
+  let sep_1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder_a.guid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  checkBookmarkObject(sep_1);
+  let sep_2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder_a.guid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  checkBookmarkObject(sep_2);
+  let sep_3 = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder_a.guid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+  checkBookmarkObject(sep_3);
+
+  function ensurePosition(info, parentGuid, index) {
+    checkBookmarkObject(info);
+    Assert.equal(info.parentGuid, parentGuid);
+    Assert.equal(info.index, index);
+  }
+
+  // folder_a: [sep_2, sep_3, sep_1], folder_b: []
+  sep_1.index = PlacesUtils.bookmarks.DEFAULT_INDEX;
+  // Note sep_1 includes parentGuid even though we're not moving the item to
+  // another folder
+  sep_1 = await PlacesUtils.bookmarks.update(sep_1);
+  ensurePosition(sep_1, folder_a.guid, 2);
+  sep_2 = await PlacesUtils.bookmarks.fetch(sep_2.guid);
+  ensurePosition(sep_2, folder_a.guid, 0);
+  sep_3 = await PlacesUtils.bookmarks.fetch(sep_3.guid);
+  ensurePosition(sep_3, folder_a.guid, 1);
+  sep_1 = await PlacesUtils.bookmarks.fetch(sep_1.guid);
+  ensurePosition(sep_1, folder_a.guid, 2);
+
+  // folder_a: [sep_2, sep_1], folder_b: [sep_3]
+  sep_3.index = PlacesUtils.bookmarks.DEFAULT_INDEX;
+  sep_3.parentGuid = folder_b.guid;
+  sep_3 = await PlacesUtils.bookmarks.update(sep_3);
+  ensurePosition(sep_3, folder_b.guid, 0);
+  sep_2 = await PlacesUtils.bookmarks.fetch(sep_2.guid);
+  ensurePosition(sep_2, folder_a.guid, 0);
+  sep_1 = await PlacesUtils.bookmarks.fetch(sep_1.guid);
+  ensurePosition(sep_1, folder_a.guid, 1);
+  sep_3 = await PlacesUtils.bookmarks.fetch(sep_3.guid);
+  ensurePosition(sep_3, folder_b.guid, 0);
+
+  // folder_a: [sep_1], folder_b: [sep_3, sep_2]
+  sep_2.index = Number.MAX_SAFE_INTEGER;
+  sep_2.parentGuid = folder_b.guid;
+  sep_2 = await PlacesUtils.bookmarks.update(sep_2);
+  ensurePosition(sep_2, folder_b.guid, 1);
+  sep_1 = await PlacesUtils.bookmarks.fetch(sep_1.guid);
+  ensurePosition(sep_1, folder_a.guid, 0);
+  sep_3 = await PlacesUtils.bookmarks.fetch(sep_3.guid);
+  ensurePosition(sep_3, folder_b.guid, 0);
+  sep_2 = await PlacesUtils.bookmarks.fetch(sep_2.guid);
+  ensurePosition(sep_2, folder_b.guid, 1);
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_insertTree_fixupOrSkipInvalidEntries.js b/toolkit/components/places/tests/bookmarks/test_insertTree_fixupOrSkipInvalidEntries.js
new file mode 100644
index 0000000000..9a676e0ed0
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_insertTree_fixupOrSkipInvalidEntries.js
@@ -0,0 +1,114 @@
+function insertTree(tree) {
+  return PlacesUtils.bookmarks.insertTree(tree, {
+    fixupOrSkipInvalidEntries: true,
+  });
+}
+
+add_task(async function () {
+  let guid = PlacesUtils.bookmarks.unfiledGuid;
+  await Assert.throws(
+    () => insertTree({ guid, children: [] }),
+    /Should have a non-zero number of children to insert./
+  );
+  await Assert.throws(
+    () => insertTree({ guid: "invalid", children: [{}] }),
+    /The parent guid is not valid/
+  );
+
+  let now = new Date();
+  let url = "http://mozilla.com/";
+  let obs = {
+    count: 0,
+    lastIndex: 0,
+    handlePlacesEvent(events) {
+      for (let event of events) {
+        obs.count++;
+        let lastIndex = obs.lastIndex;
+        obs.lastIndex = event.index;
+        if (event.itemType == PlacesUtils.bookmarks.TYPE_BOOKMARK) {
+          Assert.equal(event.url, url, "Found the expected url");
+        }
+        Assert.ok(
+          event.index == 0 || event.index == lastIndex + 1,
+          "Consecutive indices"
+        );
+        Assert.ok(event.dateAdded >= now, "Found a valid dateAdded");
+        Assert.ok(PlacesUtils.isValidGuid(event.guid), "guid is valid");
+      }
+    },
+  };
+  PlacesUtils.observers.addListener(["bookmark-added"], obs.handlePlacesEvent);
+
+  let tree = {
+    guid,
+    children: [
+      {
+        // Should be inserted, and the invalid guid should be replaced.
+        guid: "test",
+        url,
+      },
+      {
+        // Should be skipped, since the url is invalid.
+        url: "fake_url",
+      },
+      {
+        // Should be skipped, since the type is invalid.
+        url,
+        type: 999,
+      },
+      {
+        // Should be skipped, since the type is invalid.
+        type: 999,
+        children: [
+          {
+            url,
+          },
+        ],
+      },
+      {
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "test",
+        children: [
+          {
+            // Should fix lastModified and dateAdded.
+            url,
+            lastModified: null,
+          },
+          {
+            // Should be skipped, since the url is invalid.
+            url: "fake_url",
+            dateAdded: null,
+          },
+          {
+            // Should fix lastModified and dateAdded.
+            url,
+            dateAdded: undefined,
+          },
+          {
+            // Should be skipped since it's a separator with a url
+            url,
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          },
+          {
+            // Should fix lastModified and dateAdded.
+            url,
+            dateAdded: new Date(now - 86400000),
+            lastModified: new Date(now - 172800000), // less than dateAdded
+          },
+        ],
+      },
+    ],
+  };
+
+  let bms = await insertTree(tree);
+  for (let bm of bms) {
+    checkBookmarkObject(bm);
+  }
+  Assert.equal(bms.length, 5);
+  Assert.equal(obs.count, bms.length);
+
+  PlacesUtils.observers.removeListener(
+    ["bookmark-added"],
+    obs.handlePlacesEvent
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_keywords.js b/toolkit/components/places/tests/bookmarks/test_keywords.js
new file mode 100644
index 0000000000..e6cc83b980
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_keywords.js
@@ -0,0 +1,691 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+ChromeUtils.defineESModuleGetters(this, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+const URI1 = "http://test1.mozilla.org/";
+const URI2 = "http://test2.mozilla.org/";
+const URI3 = "http://test3.mozilla.org/";
+
+async function check_keyword(aURI, aKeyword) {
+  if (aKeyword) {
+    aKeyword = aKeyword.toLowerCase();
+  }
+
+  if (aKeyword) {
+    let uri = await PlacesUtils.keywords.fetch(aKeyword);
+    Assert.equal(uri.url, aURI);
+    // Check case insensitivity.
+    uri = await PlacesUtils.keywords.fetch(aKeyword.toUpperCase());
+    Assert.equal(uri.url, aURI);
+  } else {
+    let entry = await PlacesUtils.keywords.fetch({ url: aURI });
+    if (entry) {
+      throw new Error(`${aURI.spec} should not have a keyword`);
+    }
+  }
+}
+
+async function check_orphans() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.executeCached(
+    `SELECT id FROM moz_keywords k
+     WHERE NOT EXISTS (SELECT 1 FROM moz_places WHERE id = k.place_id)
+    `
+  );
+  Assert.equal(rows.length, 0);
+}
+
+function expectNotifications() {
+  const observer = {
+    notifications: [],
+    _start() {
+      this._handle = this._handle.bind(this);
+      PlacesUtils.observers.addListener(
+        ["bookmark-keyword-changed"],
+        this._handle
+      );
+    },
+    _handle(events) {
+      for (const event of events) {
+        this.notifications.push({
+          type: event.type,
+          id: event.id,
+          itemType: event.itemType,
+          url: event.url,
+          guid: event.guid,
+          parentGuid: event.parentGuid,
+          keyword: event.keyword,
+          lastModified: new Date(event.lastModified),
+          source: event.source,
+          isTagging: event.isTagging,
+        });
+      }
+    },
+    check(expected) {
+      PlacesUtils.observers.removeListener(
+        ["bookmark-keyword-changed"],
+        this._handle
+      );
+      Assert.deepEqual(this.notifications, expected);
+    },
+  };
+  observer._start();
+  return observer;
+}
+
+add_task(function test_invalid_input() {});
+
+add_task(async function test_addBookmarkAndKeyword() {
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  await check_keyword(URI1, null);
+  let fc = await foreign_count(URI1);
+  let observer = expectNotifications();
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI1,
+    title: "test",
+  });
+  await PlacesUtils.keywords.insert({ url: URI1, keyword: "keyword" });
+  let itemId = await PlacesTestUtils.promiseItemId(bookmark.guid);
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: itemId,
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+  await check_keyword(URI1, "keyword");
+  Assert.equal(await foreign_count(URI1), fc + 2); // + 1 bookmark + 1 keyword
+  await check_orphans();
+});
+
+add_task(async function test_addBookmarkToURIHavingKeyword() {
+  // The uri has already a keyword.
+  await check_keyword(URI1, "keyword");
+  let fc = await foreign_count(URI1);
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI1,
+    title: "test",
+  });
+  await check_keyword(URI1, "keyword");
+  Assert.equal(await foreign_count(URI1), fc + 1); // + 1 bookmark
+  await PlacesUtils.bookmarks.remove(bookmark);
+  await check_orphans();
+});
+
+add_task(async function test_sameKeywordDifferentURI() {
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  let fc1 = await foreign_count(URI1);
+  let fc2 = await foreign_count(URI2);
+  let observer = expectNotifications();
+
+  let bookmark2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI2,
+    title: "test2",
+  });
+  await check_keyword(URI1, "keyword");
+  await check_keyword(URI2, null);
+
+  await PlacesUtils.keywords.insert({ url: URI2, keyword: "kEyWoRd" });
+
+  let bookmark1 = await PlacesUtils.bookmarks.fetch({ url: URI1 });
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark1.guid),
+      itemType: bookmark1.type,
+      url: bookmark1.url,
+      guid: bookmark1.guid,
+      parentGuid: bookmark1.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark1.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark2.guid),
+      itemType: bookmark2.type,
+      url: bookmark2.url,
+      guid: bookmark2.guid,
+      parentGuid: bookmark2.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark2.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  // The keyword should have been "moved" to the new URI.
+  await check_keyword(URI1, null);
+  Assert.equal(await foreign_count(URI1), fc1 - 1); // - 1 keyword
+  await check_keyword(URI2, "keyword");
+  Assert.equal(await foreign_count(URI2), fc2 + 2); // + 1 bookmark + 1 keyword
+  await check_orphans();
+});
+
+add_task(async function test_sameURIDifferentKeyword() {
+  let fc = await foreign_count(URI2);
+  let observer = expectNotifications();
+
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI2,
+    title: "test2",
+  });
+  await check_keyword(URI2, "keyword");
+
+  await PlacesUtils.keywords.insert({ url: URI2, keyword: "keyword2" });
+  let bookmarks = [];
+  await PlacesUtils.bookmarks.fetch({ url: URI2 }, bm => bookmarks.push(bm));
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmarks[0].guid),
+      itemType: bookmarks[0].type,
+      url: bookmarks[0].url,
+      guid: bookmarks[0].guid,
+      parentGuid: bookmarks[0].parentGuid,
+      keyword: "keyword2",
+      lastModified: new Date(bookmarks[0].lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmarks[1].guid),
+      itemType: bookmarks[1].type,
+      url: bookmarks[1].url,
+      guid: bookmarks[1].guid,
+      parentGuid: bookmarks[1].parentGuid,
+      keyword: "keyword2",
+      lastModified: new Date(bookmarks[1].lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+  await check_keyword(URI2, "keyword2");
+  Assert.equal(await foreign_count(URI2), fc + 1); // + 1 bookmark - 1 keyword + 1 keyword
+  await check_orphans();
+});
+
+add_task(async function test_removeBookmarkWithKeyword() {
+  let fc = await foreign_count(URI2);
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI2,
+    title: "test",
+  });
+
+  // The keyword should not be removed, since there are other bookmarks yet.
+  await PlacesUtils.bookmarks.remove(bookmark);
+
+  await check_keyword(URI2, "keyword2");
+  Assert.equal(await foreign_count(URI2), fc); // + 1 bookmark - 1 bookmark
+  await check_orphans();
+});
+
+add_task(async function test_unsetKeyword() {
+  let fc = await foreign_count(URI2);
+  let observer = expectNotifications();
+
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI2,
+    title: "test",
+  });
+
+  // The keyword should be removed from any bookmark.
+  await PlacesUtils.keywords.remove("keyword2");
+
+  let bookmarks = [];
+  await PlacesUtils.bookmarks.fetch({ url: URI2 }, bookmark =>
+    bookmarks.push(bookmark)
+  );
+  Assert.equal(bookmarks.length, 3, "Check number of bookmarks");
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmarks[0].guid),
+      itemType: bookmarks[0].type,
+      url: bookmarks[0].url,
+      guid: bookmarks[0].guid,
+      parentGuid: bookmarks[0].parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmarks[0].lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmarks[1].guid),
+      itemType: bookmarks[1].type,
+      url: bookmarks[1].url,
+      guid: bookmarks[1].guid,
+      parentGuid: bookmarks[1].parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmarks[1].lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmarks[2].guid),
+      itemType: bookmarks[2].type,
+      url: bookmarks[2].url,
+      guid: bookmarks[2].guid,
+      parentGuid: bookmarks[2].parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmarks[2].lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(URI1, null);
+  await check_keyword(URI2, null);
+  Assert.equal(await foreign_count(URI2), fc); // + 1 bookmark - 1 keyword
+  await check_orphans();
+});
+
+add_task(async function test_addRemoveBookmark() {
+  let fc = await foreign_count(URI3);
+  let observer = expectNotifications();
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: URI3,
+    title: "test3",
+  });
+  let itemId = await PlacesTestUtils.promiseItemId(bookmark.guid);
+  await PlacesUtils.keywords.insert({ url: URI3, keyword: "keyword" });
+  await PlacesUtils.bookmarks.remove(bookmark);
+
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: itemId,
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(URI3, null);
+  Assert.equal(await foreign_count(URI3), fc); // +- 1 bookmark +- 1 keyword
+  await check_orphans();
+});
+
+add_task(async function test_reassign() {
+  // Should move keywords from old URL to new URL.
+  info("Old URL with keywords; new URL without keywords");
+  {
+    let oldURL = "http://example.com/1/kw";
+    let oldBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: oldURL,
+    });
+    await PlacesUtils.keywords.insert({
+      url: oldURL,
+      keyword: "kw1-1",
+      postData: "a=b",
+    });
+    await PlacesUtils.keywords.insert({
+      url: oldURL,
+      keyword: "kw1-2",
+      postData: "c=d",
+    });
+    let oldFC = await foreign_count(oldURL);
+    equal(oldFC, 3);
+
+    let newURL = "http://example.com/2/no-kw";
+    let newBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: newURL,
+    });
+    let newFC = await foreign_count(newURL);
+    equal(newFC, 1);
+
+    let observer = expectNotifications();
+    await PlacesUtils.keywords.reassign(oldURL, newURL);
+    observer.check([
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(oldBmk.guid),
+        itemType: oldBmk.type,
+        url: oldBmk.url,
+        guid: oldBmk.guid,
+        parentGuid: oldBmk.parentGuid,
+        keyword: "",
+        lastModified: new Date(oldBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "kw1-1",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "kw1-2",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+    ]);
+
+    await check_keyword(oldURL, null);
+    await check_keyword(newURL, "kw1-1");
+    await check_keyword(newURL, "kw1-2");
+
+    equal(await foreign_count(oldURL), oldFC - 2); // Removed both keywords.
+    equal(await foreign_count(newURL), newFC + 2); // Added two keywords.
+  }
+
+  // Should not remove any keywords from new URL.
+  info("Old URL without keywords; new URL with keywords");
+  {
+    let oldURL = "http://example.com/3/no-kw";
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: oldURL,
+    });
+    let oldFC = await foreign_count(oldURL);
+    equal(oldFC, 1);
+
+    let newURL = "http://example.com/4/kw";
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: newURL,
+    });
+    await PlacesUtils.keywords.insert({
+      url: newURL,
+      keyword: "kw4-1",
+    });
+    let newFC = await foreign_count(newURL);
+    equal(newFC, 2);
+
+    let observer = expectNotifications();
+    await PlacesUtils.keywords.reassign(oldURL, newURL);
+    observer.check([]);
+
+    await check_keyword(newURL, "kw4-1");
+
+    equal(await foreign_count(oldURL), oldFC);
+    equal(await foreign_count(newURL), newFC);
+  }
+
+  // Should remove all keywords from new URL, then move keywords from old URL.
+  info("Old URL with keywords; new URL with keywords");
+  {
+    let oldURL = "http://example.com/8/kw";
+    let oldBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: oldURL,
+    });
+    await PlacesUtils.keywords.insert({
+      url: oldURL,
+      keyword: "kw8-1",
+      postData: "a=b",
+    });
+    await PlacesUtils.keywords.insert({
+      url: oldURL,
+      keyword: "kw8-2",
+      postData: "c=d",
+    });
+    let oldFC = await foreign_count(oldURL);
+    equal(oldFC, 3);
+
+    let newURL = "http://example.com/9/kw";
+    let newBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      url: newURL,
+    });
+    await PlacesUtils.keywords.insert({
+      url: newURL,
+      keyword: "kw9-1",
+    });
+    let newFC = await foreign_count(newURL);
+    equal(newFC, 2);
+
+    let observer = expectNotifications();
+    await PlacesUtils.keywords.reassign(oldURL, newURL);
+    observer.check([
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(oldBmk.guid),
+        itemType: oldBmk.type,
+        url: oldBmk.url,
+        guid: oldBmk.guid,
+        parentGuid: oldBmk.parentGuid,
+        keyword: "",
+        lastModified: new Date(oldBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "kw8-1",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+      {
+        type: "bookmark-keyword-changed",
+        id: await PlacesTestUtils.promiseItemId(newBmk.guid),
+        itemType: newBmk.type,
+        url: newBmk.url,
+        guid: newBmk.guid,
+        parentGuid: newBmk.parentGuid,
+        keyword: "kw8-2",
+        lastModified: new Date(newBmk.lastModified),
+        source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+        isTagging: false,
+      },
+    ]);
+
+    await check_keyword(oldURL, null);
+    await check_keyword(newURL, "kw8-1");
+    await check_keyword(newURL, "kw8-2");
+
+    equal(await foreign_count(oldURL), oldFC - 2); // Removed both keywords.
+    equal(await foreign_count(newURL), newFC + 1); // Removed old keyword; added two keywords.
+  }
+
+  // Should do nothing.
+  info("Old URL without keywords; new URL without keywords");
+  {
+    let oldURL = "http://example.com/10/no-kw";
+    let oldFC = await foreign_count(oldURL);
+
+    let newURL = "http://example.com/11/no-kw";
+    let newFC = await foreign_count(newURL);
+
+    let observer = expectNotifications();
+    await PlacesUtils.keywords.reassign(oldURL, newURL);
+    observer.check([]);
+
+    equal(await foreign_count(oldURL), oldFC);
+    equal(await foreign_count(newURL), newFC);
+  }
+
+  await check_orphans();
+});
+
+add_task(async function test_invalidation() {
+  info("Insert bookmarks");
+  let fx = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "Get Firefox!",
+    url: "http://getfirefox.com",
+  });
+  let tb = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "Get Thunderbird!",
+    url: "http://getthunderbird.com",
+  });
+
+  info("Set keywords for bookmarks");
+  await PlacesUtils.keywords.insert({ url: fx.url, keyword: "fx" });
+  await PlacesUtils.keywords.insert({ url: tb.url, keyword: "tb" });
+
+  info("Invalidate cached keywords");
+  await PlacesUtils.keywords.invalidateCachedKeywords();
+
+  info("Change URL of bookmark with keyword");
+  let promiseNotification = PlacesTestUtils.waitForNotification(
+    "bookmark-keyword-changed",
+    events =>
+      events.some(event => event.guid === fx.guid && event.keyword === "fx")
+  );
+  await PlacesUtils.bookmarks.update({
+    guid: fx.guid,
+    url: "https://www.mozilla.org/firefox",
+  });
+  await promiseNotification;
+
+  let entriesByKeyword = [];
+  await PlacesUtils.keywords.fetch({ keyword: "fx" }, e =>
+    entriesByKeyword.push(e.url.href)
+  );
+  deepEqual(
+    entriesByKeyword,
+    ["https://www.mozilla.org/firefox"],
+    "Should return new URL for keyword"
+  );
+
+  ok(
+    !(await PlacesUtils.keywords.fetch({ url: "http://getfirefox.com" })),
+    "Should not return keywords for old URL"
+  );
+
+  let entiresByURL = [];
+  await PlacesUtils.keywords.fetch(
+    { url: "https://www.mozilla.org/firefox" },
+    e => entiresByURL.push(e.keyword)
+  );
+  deepEqual(entiresByURL, ["fx"], "Should return keyword for new URL");
+
+  info("Invalidate cached keywords");
+  await PlacesUtils.keywords.invalidateCachedKeywords();
+
+  info("Remove bookmark with keyword");
+  await PlacesUtils.bookmarks.remove(tb.guid);
+
+  ok(
+    !(await PlacesUtils.keywords.fetch({ url: "http://getthunderbird.com" })),
+    "Should not return keywords for removed bookmark URL"
+  );
+
+  ok(
+    !(await PlacesUtils.keywords.fetch({ keyword: "tb" })),
+    "Should not return URL for removed bookmark keyword"
+  );
+  await check_orphans();
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_eraseAllBookmarks() {
+  info("Insert bookmarks");
+  let fx = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "Get Firefox!",
+    url: "http://getfirefox.com",
+  });
+  let tb = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "Get Thunderbird!",
+    url: "http://getthunderbird.com",
+  });
+
+  info("Set keywords for bookmarks");
+  await PlacesUtils.keywords.insert({ url: fx.url, keyword: "fx" });
+  await PlacesUtils.keywords.insert({ url: tb.url, keyword: "tb" });
+
+  info("Erase everything");
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  ok(
+    !(await PlacesUtils.keywords.fetch({ keyword: "fx" })),
+    "Should remove Firefox keyword"
+  );
+
+  ok(
+    !(await PlacesUtils.keywords.fetch({ keyword: "tb" })),
+    "Should remove Thunderbird keyword"
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_removeFolderTransaction_reinsert.js b/toolkit/components/places/tests/bookmarks/test_removeFolderTransaction_reinsert.js
new file mode 100644
index 0000000000..80a0b1dd9f
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_removeFolderTransaction_reinsert.js
@@ -0,0 +1,115 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+/**
+ * This test ensures that reinserting a folder within a transaction gives it
+ * the same GUID, and passes it to the observers.
+ */
+
+add_task(async function test_removeFolderTransaction_reinsert() {
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "Test folder",
+  });
+  let fx = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    title: "Get Firefox!",
+    url: "http://getfirefox.com",
+  });
+  let tb = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    title: "Get Thunderbird!",
+    url: "http://getthunderbird.com",
+  });
+
+  let notifications = [];
+  function checkNotifications(expected, message) {
+    deepEqual(notifications, expected, message);
+    notifications.length = 0;
+  }
+
+  let listener = events => {
+    for (let event of events) {
+      notifications.push([
+        event.type,
+        event.id,
+        event.parentId,
+        event.guid,
+        event.parentGuid,
+      ]);
+    }
+  };
+  PlacesUtils.observers.addListener(
+    ["bookmark-added", "bookmark-removed"],
+    listener
+  );
+  PlacesUtils.registerShutdownFunction(function () {
+    PlacesUtils.observers.removeListener(
+      ["bookmark-added", "bookmark-removed"],
+      listener
+    );
+  });
+
+  let transaction = PlacesTransactions.Remove({ guid: folder.guid });
+
+  let folderId = await PlacesTestUtils.promiseItemId(folder.guid);
+  let fxId = await PlacesTestUtils.promiseItemId(fx.guid);
+  let tbId = await PlacesTestUtils.promiseItemId(tb.guid);
+
+  await transaction.transact();
+  let bookmarksMenuItemId = await PlacesTestUtils.promiseItemId(
+    PlacesUtils.bookmarks.menuGuid
+  );
+  checkNotifications(
+    [
+      ["bookmark-removed", tbId, folderId, tb.guid, folder.guid],
+      ["bookmark-removed", fxId, folderId, fx.guid, folder.guid],
+      [
+        "bookmark-removed",
+        folderId,
+        bookmarksMenuItemId,
+        folder.guid,
+        PlacesUtils.bookmarks.menuGuid,
+      ],
+    ],
+    "Executing transaction should remove folder and its descendants"
+  );
+
+  await PlacesTransactions.undo();
+
+  folderId = await PlacesTestUtils.promiseItemId(folder.guid);
+  fxId = await PlacesTestUtils.promiseItemId(fx.guid);
+  tbId = await PlacesTestUtils.promiseItemId(tb.guid);
+
+  checkNotifications(
+    [
+      [
+        "bookmark-added",
+        folderId,
+        bookmarksMenuItemId,
+        folder.guid,
+        PlacesUtils.bookmarks.menuGuid,
+      ],
+      ["bookmark-added", fxId, folderId, fx.guid, folder.guid],
+      ["bookmark-added", tbId, folderId, tb.guid, folder.guid],
+    ],
+    "Undo should reinsert folder with different id but same GUID"
+  );
+
+  await PlacesTransactions.redo();
+
+  checkNotifications(
+    [
+      ["bookmark-removed", tbId, folderId, tb.guid, folder.guid],
+      ["bookmark-removed", fxId, folderId, fx.guid, folder.guid],
+      [
+        "bookmark-removed",
+        folderId,
+        bookmarksMenuItemId,
+        folder.guid,
+        PlacesUtils.bookmarks.menuGuid,
+      ],
+    ],
+    "Redo should pass the GUID to observer"
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_savedsearches.js b/toolkit/components/places/tests/bookmarks/test_savedsearches.js
new file mode 100644
index 0000000000..a10307983d
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_savedsearches.js
@@ -0,0 +1,224 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// a search term that matches a default bookmark
+const searchTerm = "about";
+
+var testRoot;
+
+add_task(async function setup() {
+  // create a folder to hold all the tests
+  // this makes the tests more tolerant of changes to the default bookmarks set
+  // also, name it using the search term, for testing that containers that match don't show up in query results
+  testRoot = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: searchTerm,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+});
+
+add_task(async function test_savedsearches_bookmarks() {
+  // add a bookmark that matches the search term
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: searchTerm,
+    url: "http://foo.com",
+  });
+
+  // create a saved-search that matches a default bookmark
+  let search = await PlacesUtils.bookmarks.insert({
+    parentGuid: testRoot.guid,
+    title: searchTerm,
+    url:
+      "place:terms=" +
+      searchTerm +
+      "&excludeQueries=1&expandQueries=1&queryType=1",
+  });
+
+  // query for the test root, expandQueries=0
+  // the query should show up as a regular bookmark
+  try {
+    let options = PlacesUtils.history.getNewQueryOptions();
+    options.expandQueries = 0;
+    let query = PlacesUtils.history.getNewQuery();
+    query.setParents([testRoot.guid]);
+    let result = PlacesUtils.history.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.equal(cc, 1);
+    for (let i = 0; i < cc; i++) {
+      let node = rootNode.getChild(i);
+      // test that queries have valid itemId
+      Assert.ok(node.itemId > 0);
+      // test that the container is closed
+      node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+      Assert.equal(node.containerOpen, false);
+    }
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("expandQueries=0 query error: " + ex);
+  }
+
+  // bookmark saved search
+  // query for the test root, expandQueries=1
+  // the query should show up as a query container, with 1 child
+  try {
+    let options = PlacesUtils.history.getNewQueryOptions();
+    options.expandQueries = 1;
+    let query = PlacesUtils.history.getNewQuery();
+    query.setParents([testRoot.guid]);
+    let result = PlacesUtils.history.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.equal(cc, 1);
+    for (let i = 0; i < cc; i++) {
+      let node = rootNode.getChild(i);
+      // test that query node type is container when expandQueries=1
+      Assert.equal(node.type, node.RESULT_TYPE_QUERY);
+      // test that queries (as containers) have valid itemId
+      Assert.ok(node.itemId > 0);
+      node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+      node.containerOpen = true;
+
+      // test that queries have children when excludeItems=1
+      // test that query nodes don't show containers (shouldn't have our folder that matches)
+      // test that queries don't show themselves in query results (shouldn't have our saved search)
+      Assert.equal(node.childCount, 1);
+
+      // test that bookmark shows in query results
+      var item = node.getChild(0);
+      Assert.equal(item.bookmarkGuid, bookmark.guid);
+
+      // XXX - FAILING - test live-update of query results - add a bookmark that matches the query
+      // var tmpBmId = PlacesUtils.bookmarks.insertBookmark(
+      //  root, uri("http://" + searchTerm + ".com"),
+      //  PlacesUtils.bookmarks.DEFAULT_INDEX, searchTerm + "blah");
+      // do_check_eq(query.childCount, 2);
+
+      // XXX - test live-update of query results - delete a bookmark that matches the query
+      // PlacesUtils.bookmarks.removeItem(tmpBMId);
+      // do_check_eq(query.childCount, 1);
+
+      // test live-update of query results - add a folder that matches the query
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        title: searchTerm + "zaa",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      });
+      Assert.equal(node.childCount, 1);
+      // test live-update of query results - add a query that matches the query
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        title: searchTerm + "blah",
+        url: "place:terms=foo&excludeQueries=1&expandQueries=1&queryType=1",
+      });
+      Assert.equal(node.childCount, 1);
+    }
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("expandQueries=1 bookmarks query: " + ex);
+  }
+
+  // delete the bookmark search
+  await PlacesUtils.bookmarks.remove(search);
+});
+
+add_task(async function test_savedsearches_history() {
+  // add a visit that matches the search term
+  var testURI = uri("http://" + searchTerm + ".com");
+  await PlacesTestUtils.addVisits({ uri: testURI, title: searchTerm });
+
+  // create a saved-search that matches the visit we added
+  var searchItem = await PlacesUtils.bookmarks.insert({
+    parentGuid: testRoot.guid,
+    title: searchTerm,
+    url:
+      "place:terms=" +
+      searchTerm +
+      "&excludeQueries=1&expandQueries=1&queryType=0",
+  });
+
+  // query for the test root, expandQueries=1
+  // the query should show up as a query container, with 1 child
+  try {
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.expandQueries = 1;
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([testRoot.guid]);
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var rootNode = result.root;
+    rootNode.containerOpen = true;
+    var cc = rootNode.childCount;
+    Assert.equal(cc, 1);
+    for (var i = 0; i < cc; i++) {
+      var node = rootNode.getChild(i);
+      // test that query node type is container when expandQueries=1
+      Assert.equal(node.type, node.RESULT_TYPE_QUERY);
+      // test that queries (as containers) have valid itemId
+      Assert.equal(node.bookmarkGuid, searchItem.guid);
+      node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+      node.containerOpen = true;
+
+      // test that queries have children when excludeItems=1
+      // test that query nodes don't show containers (shouldn't have our folder that matches)
+      // test that queries don't show themselves in query results (shouldn't have our saved search)
+      Assert.equal(node.childCount, 1);
+
+      // test that history visit shows in query results
+      var item = node.getChild(0);
+      Assert.equal(item.type, item.RESULT_TYPE_URI);
+      Assert.equal(item.itemId, -1); // history visit
+      Assert.equal(item.uri, testURI.spec); // history visit
+
+      // test live-update of query results - add a history visit that matches the query
+      await PlacesTestUtils.addVisits({
+        uri: uri("http://foo.com"),
+        title: searchTerm + "blah",
+      });
+      Assert.equal(node.childCount, 2);
+
+      // test live-update of query results - delete a history visit that matches the query
+      await PlacesUtils.history.remove("http://foo.com");
+      Assert.equal(node.childCount, 1);
+      node.containerOpen = false;
+    }
+
+    // test live-update of moved queries
+    let tmpFolder = await PlacesUtils.bookmarks.insert({
+      parentGuid: testRoot.guid,
+      title: "foo",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+
+    searchItem.parentGuid = tmpFolder.guid;
+    await PlacesUtils.bookmarks.update(searchItem);
+    var tmpFolderNode = rootNode.getChild(0);
+    Assert.equal(tmpFolderNode.bookmarkGuid, tmpFolder.guid);
+    tmpFolderNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    tmpFolderNode.containerOpen = true;
+    Assert.equal(tmpFolderNode.childCount, 1);
+
+    // test live-update of renamed queries
+    searchItem.title = "foo";
+    await PlacesUtils.bookmarks.update(searchItem);
+    Assert.equal(tmpFolderNode.title, "foo");
+
+    // test live-update of deleted queries
+    await PlacesUtils.bookmarks.remove(searchItem);
+    Assert.throws(
+      () => (tmpFolderNode = rootNode.getChild(1)),
+      /NS_ERROR_ILLEGAL_VALUE/,
+      "getting a deleted child should throw"
+    );
+
+    tmpFolderNode.containerOpen = false;
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("expandQueries=1 bookmarks query: " + ex);
+  }
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_sync_fields.js b/toolkit/components/places/tests/bookmarks/test_sync_fields.js
new file mode 100644
index 0000000000..0a6f53fb85
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_sync_fields.js
@@ -0,0 +1,438 @@
+// Tracks a set of bookmark guids and their syncChangeCounter field and
+// provides a simple way for the test to check the correct fields had the
+// counter incremented.
+class CounterTracker {
+  constructor() {
+    this.tracked = new Map();
+  }
+
+  async _getCounter(guid) {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(guid);
+    if (!fields.length) {
+      throw new Error(`Item ${guid} does not exist`);
+    }
+    return fields[0].syncChangeCounter;
+  }
+
+  // Call this after creating a new bookmark.
+  async track(guid, name, expectedInitial = 1) {
+    if (this.tracked.has(guid)) {
+      throw new Error(`Already tracking item ${guid}`);
+    }
+    let initial = await this._getCounter(guid);
+    Assert.equal(
+      initial,
+      expectedInitial,
+      `Initial value of item '${name}' is correct`
+    );
+    this.tracked.set(guid, { name, value: expectedInitial });
+  }
+
+  // Call this to check *only* the specified IDs had a change increment, and
+  // that none of the other "tracked" ones did.
+  async check(...expectedToIncrement) {
+    info(`Checking counter for items ${JSON.stringify(expectedToIncrement)}`);
+    for (let [guid, entry] of this.tracked) {
+      let { name, value } = entry;
+      let newValue = await this._getCounter(guid);
+      let desc = `record '${name}' (guid=${guid})`;
+      if (expectedToIncrement.includes(guid)) {
+        // Note we don't check specifically for +1, as some changes will
+        // increment the counter by more than 1 (which is OK).
+        Assert.ok(
+          newValue > value,
+          `${desc} was expected to increment - was ${value}, now ${newValue}`
+        );
+        this.tracked.set(guid, { name, value: newValue });
+      } else {
+        Assert.equal(newValue, value, `${desc} was NOT expected to increment`);
+      }
+    }
+  }
+}
+
+async function checkSyncFields(guid, expected) {
+  let results = await PlacesTestUtils.fetchBookmarkSyncFields(guid);
+  if (!results.length) {
+    throw new Error(`Missing sync fields for ${guid}`);
+  }
+  for (let name in expected) {
+    let expectedValue = expected[name];
+    Assert.equal(
+      results[0][name],
+      expectedValue,
+      `field ${name} matches item ${guid}`
+    );
+  }
+}
+
+// Common test cases for sync field changes.
+class TestCases {
+  async run() {
+    info("Test 1: inserts, updates, tags, and keywords");
+    try {
+      await this.testChanges();
+    } finally {
+      info("Reset sync fields after test 1");
+      await PlacesTestUtils.markBookmarksAsSynced();
+    }
+
+    if ("moveItem" in this && "reorder" in this) {
+      info("Test 2: reparenting");
+      try {
+        await this.testReparenting();
+      } finally {
+        info("Reset sync fields after test 2");
+        await PlacesTestUtils.markBookmarksAsSynced();
+      }
+    }
+
+    if ("insertSeparator" in this) {
+      info("Test 3: separators");
+      try {
+        await this.testSeparators();
+      } finally {
+        info("Reset sync fields after test 3");
+        await PlacesTestUtils.markBookmarksAsSynced();
+      }
+    }
+  }
+
+  async testChanges() {
+    let testUri = NetUtil.newURI("http://test.mozilla.org");
+
+    let guid = await this.insertBookmark(
+      PlacesUtils.bookmarks.unfiledGuid,
+      testUri,
+      PlacesUtils.bookmarks.DEFAULT_INDEX,
+      "bookmark title"
+    );
+    info(`Inserted bookmark ${guid}`);
+    await checkSyncFields(guid, {
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      syncChangeCounter: 1,
+    });
+
+    // Pretend Sync just did whatever it does
+    await PlacesTestUtils.setBookmarkSyncFields({
+      guid,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    });
+    info(`Updated sync status of ${guid}`);
+    await checkSyncFields(guid, {
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      syncChangeCounter: 1,
+    });
+
+    // update it - it should increment the change counter
+    await this.setTitle(guid, "new title");
+    info(`Changed title of ${guid}`);
+    await checkSyncFields(guid, {
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      syncChangeCounter: 2,
+    });
+
+    // Tagging a bookmark should update its change counter.
+    await this.tagURI(testUri, ["test-tag"]);
+    info(`Tagged bookmark ${guid}`);
+    await checkSyncFields(guid, { syncChangeCounter: 3 });
+
+    if ("setKeyword" in this) {
+      await this.setKeyword(guid, "keyword");
+      info(`Set keyword for bookmark ${guid}`);
+      await checkSyncFields(guid, { syncChangeCounter: 4 });
+    }
+    if ("removeKeyword" in this) {
+      await this.removeKeyword(guid, "keyword");
+      info(`Removed keyword from bookmark ${guid}`);
+      await checkSyncFields(guid, { syncChangeCounter: 5 });
+    }
+  }
+
+  async testSeparators() {
+    let insertSyncedBookmark = uri => {
+      return this.insertBookmark(
+        PlacesUtils.bookmarks.unfiledGuid,
+        NetUtil.newURI(uri),
+        PlacesUtils.bookmarks.DEFAULT_INDEX,
+        "A bookmark name"
+      );
+    };
+
+    await insertSyncedBookmark("http://foo.bar");
+    let secondBmk = await insertSyncedBookmark("http://bar.foo");
+    let sepGuid = await this.insertSeparator(
+      PlacesUtils.bookmarks.unfiledGuid,
+      PlacesUtils.bookmarks.DEFAULT_INDEX
+    );
+    await insertSyncedBookmark("http://barbar.foo");
+
+    info("Move a bookmark around the separator");
+    await this.moveItem(secondBmk, PlacesUtils.bookmarks.unfiledGuid, 4);
+    await checkSyncFields(sepGuid, { syncChangeCounter: 2 });
+
+    info("Move a separator around directly");
+    await this.moveItem(sepGuid, PlacesUtils.bookmarks.unfiledGuid, 0);
+    await checkSyncFields(sepGuid, { syncChangeCounter: 3 });
+  }
+
+  async testReparenting() {
+    let counterTracker = new CounterTracker();
+
+    let folder1 = await this.createFolder(
+      PlacesUtils.bookmarks.unfiledGuid,
+      "folder1",
+      PlacesUtils.bookmarks.DEFAULT_INDEX
+    );
+    info(`Created the first folder, guid is ${folder1}`);
+
+    // New folder should have a change recorded.
+    await counterTracker.track(folder1, "folder 1");
+
+    // Put a new bookmark in the folder.
+    let testUri = NetUtil.newURI("http://test2.mozilla.org");
+    let child1 = await this.insertBookmark(
+      folder1,
+      testUri,
+      PlacesUtils.bookmarks.DEFAULT_INDEX,
+      "bookmark 1"
+    );
+    info(`Created a new bookmark into ${folder1}, guid is ${child1}`);
+    // both the folder and the child should have a change recorded.
+    await counterTracker.track(child1, "child 1");
+    await counterTracker.check(folder1);
+
+    // A new child in the folder at index 0 - even though the existing child
+    // was bumped down the list, it should *not* have a change recorded.
+    let child2 = await this.insertBookmark(folder1, testUri, 0, "bookmark 2");
+    info(
+      `Created a second new bookmark into folder ${folder1}, guid is ${child2}`
+    );
+
+    await counterTracker.track(child2, "child 2");
+    await counterTracker.check(folder1);
+
+    // Move the items within the same folder - this should result in just a
+    // change for the parent, but for neither of the children.
+    // child0 is currently at index 0, so move child1 there.
+    await this.moveItem(child1, folder1, 0);
+    await counterTracker.check(folder1);
+
+    // Another folder to play with.
+    let folder2 = await this.createFolder(
+      PlacesUtils.bookmarks.unfiledGuid,
+      "folder2",
+      PlacesUtils.bookmarks.DEFAULT_INDEX
+    );
+    info(`Created a second new folder, guid is ${folder2}`);
+    await counterTracker.track(folder2, "folder 2");
+    // nothing else has changed.
+    await counterTracker.check();
+
+    // Move one of the children to the new folder.
+    info(
+      `Moving bookmark ${child2} from folder ${folder1} to folder ${folder2}`
+    );
+    await this.moveItem(child2, folder2, PlacesUtils.bookmarks.DEFAULT_INDEX);
+    // child1 should have no change, everything should have a new change.
+    await counterTracker.check(folder1, folder2, child2);
+
+    // Move the new folder to another root.
+    await this.moveItem(
+      folder2,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.DEFAULT_INDEX
+    );
+    info(`Moving folder ${folder2} to toolbar`);
+    await counterTracker.check(
+      folder2,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid
+    );
+
+    let child3 = await this.insertBookmark(folder2, testUri, 0, "bookmark 3");
+    info(`Prepended child ${child3} to folder ${folder2}`);
+    await counterTracker.check(folder2, child3);
+
+    // Reordering should only track the parent.
+    await this.reorder(folder2, [child2, child3]);
+    info(`Reorder children of ${folder2}`);
+    await counterTracker.check(folder2);
+
+    // All fields still have a syncStatus of SYNC_STATUS_NEW - so deleting them
+    // should *not* cause any deleted items to be written.
+    await this.removeItem(folder1);
+    Assert.equal((await PlacesTestUtils.fetchSyncTombstones()).length, 0);
+
+    // Set folder2 and child2 to have a state of SYNC_STATUS_NORMAL and deleting
+    // them will cause both GUIDs to be written to moz_bookmarks_deleted.
+    await PlacesTestUtils.setBookmarkSyncFields({
+      guid: folder2,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    });
+    await PlacesTestUtils.setBookmarkSyncFields({
+      guid: child2,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    });
+    await this.removeItem(folder2);
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    let tombstoneGuids = sortBy(tombstones, "guid").map(({ guid }) => guid);
+    Assert.equal(tombstoneGuids.length, 2);
+    Assert.deepEqual(tombstoneGuids, [folder2, child2].sort(compareAscending));
+  }
+}
+
+// Exercises the legacy, synchronous `nsINavBookmarksService` calls implemented
+// in C++.
+class SyncTestCases extends TestCases {
+  async createFolder(parentGuid, title, index) {
+    let parentId = await PlacesTestUtils.promiseItemId(parentGuid);
+    let id = PlacesUtils.bookmarks.createFolder(parentId, title, index);
+    return PlacesTestUtils.promiseItemGuid(id);
+  }
+
+  async insertBookmark(parentGuid, uri, index, title) {
+    let parentId = await PlacesTestUtils.promiseItemId(parentGuid);
+    let id = PlacesUtils.bookmarks.insertBookmark(parentId, uri, index, title);
+    return PlacesTestUtils.promiseItemGuid(id);
+  }
+
+  async removeItem(guid) {
+    let id = await PlacesTestUtils.promiseItemId(guid);
+    PlacesUtils.bookmarks.removeItem(id);
+  }
+
+  async setTitle(guid, title) {
+    let id = await PlacesTestUtils.promiseItemId(guid);
+    PlacesUtils.bookmarks.setItemTitle(id, title);
+  }
+
+  async tagURI(uri, tags) {
+    PlacesUtils.tagging.tagURI(uri, tags);
+  }
+}
+
+async function findTagFolder(tag) {
+  let db = await PlacesUtils.promiseDBConnection();
+  let results = await db.executeCached(
+    `
+  SELECT guid
+  FROM moz_bookmarks
+  WHERE type = :type AND
+        parent = :tagsFolderId AND
+        title = :tag`,
+    {
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      tagsFolderId: PlacesUtils.tagsFolderId,
+      tag,
+    }
+  );
+  return results.length ? results[0].getResultByName("guid") : null;
+}
+
+// Exercises the new, async calls implemented in `Bookmarks.jsm`.
+class AsyncTestCases extends TestCases {
+  async createFolder(parentGuid, title, index) {
+    let item = await PlacesUtils.bookmarks.insert({
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parentGuid,
+      title,
+      index,
+    });
+    return item.guid;
+  }
+
+  async insertBookmark(parentGuid, uri, index, title) {
+    let item = await PlacesUtils.bookmarks.insert({
+      parentGuid,
+      url: uri,
+      index,
+      title,
+    });
+    return item.guid;
+  }
+
+  async insertSeparator(parentGuid, index) {
+    let item = await PlacesUtils.bookmarks.insert({
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      parentGuid,
+      index,
+    });
+    return item.guid;
+  }
+
+  async moveItem(guid, newParentGuid, index) {
+    await PlacesUtils.bookmarks.update({
+      guid,
+      parentGuid: newParentGuid,
+      index,
+    });
+  }
+
+  async removeItem(guid) {
+    await PlacesUtils.bookmarks.remove(guid);
+  }
+
+  async setTitle(guid, title) {
+    await PlacesUtils.bookmarks.update({ guid, title });
+  }
+
+  async setKeyword(guid, keyword) {
+    let item = await PlacesUtils.bookmarks.fetch(guid);
+    if (!item) {
+      throw new Error(
+        `Cannot set keyword ${keyword} on nonexistent bookmark ${guid}`
+      );
+    }
+    await PlacesUtils.keywords.insert({ keyword, url: item.url });
+  }
+
+  async removeKeyword(guid, keyword) {
+    let item = await PlacesUtils.bookmarks.fetch(guid);
+    if (!item) {
+      throw new Error(
+        `Cannot remove keyword ${keyword} from nonexistent bookmark ${guid}`
+      );
+    }
+    let entry = await PlacesUtils.keywords.fetch({ keyword, url: item.url });
+    if (!entry) {
+      throw new Error(`Keyword ${keyword} not set on bookmark ${guid}`);
+    }
+    await PlacesUtils.keywords.remove(entry);
+  }
+
+  // There's no async API for tags, but the `PlacesUtils.bookmarks` methods are
+  // tag-aware, and should bump the change counters for tagged bookmarks when
+  // called directly.
+  async tagURI(uri, tags) {
+    for (let tag of tags) {
+      let tagFolderGuid = await findTagFolder(tag);
+      if (!tagFolderGuid) {
+        let tagFolder = await PlacesUtils.bookmarks.insert({
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          parentGuid: PlacesUtils.bookmarks.tagsGuid,
+          title: tag,
+        });
+        tagFolderGuid = tagFolder.guid;
+      }
+      await PlacesUtils.bookmarks.insert({
+        url: uri,
+        parentGuid: tagFolderGuid,
+      });
+    }
+  }
+
+  async reorder(parentGuid, childGuids) {
+    await PlacesUtils.bookmarks.reorder(parentGuid, childGuids);
+  }
+}
+
+add_task(async function test_sync_api() {
+  let tests = new SyncTestCases();
+  await tests.run();
+});
+
+add_task(async function test_async_api() {
+  let tests = new AsyncTestCases();
+  await tests.run();
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_tags.js b/toolkit/components/places/tests/bookmarks/test_tags.js
new file mode 100644
index 0000000000..c98d0c0ebd
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_tags.js
@@ -0,0 +1,128 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_fetchTags() {
+  let tags = await PlacesUtils.bookmarks.fetchTags();
+  Assert.deepEqual(tags, []);
+
+  let bm = await PlacesUtils.bookmarks.insert({
+    url: "http://page1.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+
+  PlacesUtils.tagging.tagURI(bm.url.URI, ["1", "2"]);
+  tags = await PlacesUtils.bookmarks.fetchTags();
+  Assert.deepEqual(tags, [
+    { name: "1", count: 1 },
+    { name: "2", count: 1 },
+  ]);
+
+  PlacesUtils.tagging.untagURI(bm.url.URI, ["1"]);
+  tags = await PlacesUtils.bookmarks.fetchTags();
+  Assert.deepEqual(tags, [{ name: "2", count: 1 }]);
+
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    url: "http://page2.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  PlacesUtils.tagging.tagURI(bm2.url.URI, ["2", "3"]);
+  tags = await PlacesUtils.bookmarks.fetchTags();
+  Assert.deepEqual(tags, [
+    { name: "2", count: 2 },
+    { name: "3", count: 1 },
+  ]);
+});
+
+add_task(async function test_fetch_by_tags() {
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ tags: "" }),
+    /Invalid value for property 'tags'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ tags: [] }),
+    /Invalid value for property 'tags'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ tags: null }),
+    /Invalid value for property 'tags'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ tags: [""] }),
+    /Invalid value for property 'tags'/
+  );
+  await Assert.rejects(
+    PlacesUtils.bookmarks.fetch({ tags: ["valid", null] }),
+    /Invalid value for property 'tags'/
+  );
+
+  info("Add bookmarks with tags.");
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    url: "http://bacon.org/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  PlacesUtils.tagging.tagURI(bm1.url.URI, ["egg", "ratafià"]);
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    url: "http://mushroom.org/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  PlacesUtils.tagging.tagURI(bm2.url.URI, ["egg"]);
+
+  info("Fetch a single tag.");
+  let bms = [];
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch({ tags: ["egg"] }, b => bms.push(b)))
+      .guid,
+    bm2.guid,
+    "Found the expected recent bookmark"
+  );
+  Assert.deepEqual(
+    bms.map(b => b.guid),
+    [bm2.guid, bm1.guid],
+    "Found the expected bookmarks"
+  );
+
+  info("Fetch multiple tags.");
+  bms = [];
+  Assert.equal(
+    (
+      await PlacesUtils.bookmarks.fetch({ tags: ["egg", "ratafià"] }, b =>
+        bms.push(b)
+      )
+    ).guid,
+    bm1.guid,
+    "Found the expected recent bookmark"
+  );
+  Assert.deepEqual(
+    bms.map(b => b.guid),
+    [bm1.guid],
+    "Found the expected bookmarks"
+  );
+
+  info("Fetch a nonexisting tag.");
+  bms = [];
+  Assert.equal(
+    await PlacesUtils.bookmarks.fetch({ tags: ["egg", "tomato"] }, b =>
+      bms.push(b)
+    ),
+    null,
+    "Should not find any bookmark"
+  );
+  Assert.deepEqual(bms, [], "Should not find any bookmark");
+
+  info("Check case insensitive");
+  bms = [];
+  Assert.equal(
+    (
+      await PlacesUtils.bookmarks.fetch({ tags: ["eGg", "raTafiÀ"] }, b =>
+        bms.push(b)
+      )
+    ).guid,
+    bm1.guid,
+    "Found the expected recent bookmark"
+  );
+  Assert.deepEqual(
+    bms.map(b => b.guid),
+    [bm1.guid],
+    "Found the expected bookmarks"
+  );
+});
diff --git a/toolkit/components/places/tests/bookmarks/test_untitled.js b/toolkit/components/places/tests/bookmarks/test_untitled.js
new file mode 100644
index 0000000000..25024ac7fc
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/test_untitled.js
@@ -0,0 +1,114 @@
+add_task(async function test_untitled_visited_bookmark() {
+  let fxURI = uri("http://getfirefox.com");
+
+  await PlacesUtils.history.insert({
+    url: fxURI,
+    title: "Get Firefox!",
+    visits: [
+      {
+        date: new Date(),
+        transition: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+    ],
+  });
+
+  let { root: node } = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+
+  try {
+    let fxBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      url: fxURI,
+    });
+    strictEqual(fxBmk.title, "", "Visited bookmark should not have title");
+
+    await PlacesTestUtils.promiseAsyncUpdates();
+
+    let fxBmkId = await PlacesTestUtils.promiseItemId(fxBmk.guid);
+    strictEqual(
+      PlacesUtils.bookmarks.getItemTitle(fxBmkId),
+      "",
+      "Should return empty string for untitled visited bookmark"
+    );
+
+    let fxBmkNode = node.getChild(0);
+    equal(fxBmkNode.itemId, fxBmkId, "Visited bookmark ID should match");
+    strictEqual(
+      fxBmkNode.title,
+      "",
+      "Visited bookmark node should not have title"
+    );
+  } finally {
+    node.containerOpen = false;
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_untitled_unvisited_bookmark() {
+  let tbURI = uri("http://getthunderbird.com");
+
+  let { root: node } = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+
+  try {
+    let tbBmk = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      url: tbURI,
+    });
+    strictEqual(tbBmk.title, "", "Unvisited bookmark should not have title");
+
+    await PlacesTestUtils.promiseAsyncUpdates();
+
+    let tbBmkId = await PlacesTestUtils.promiseItemId(tbBmk.guid);
+    strictEqual(
+      PlacesUtils.bookmarks.getItemTitle(tbBmkId),
+      "",
+      "Should return empty string for untitled unvisited bookmark"
+    );
+
+    let tbBmkNode = node.getChild(0);
+    equal(tbBmkNode.itemId, tbBmkId, "Unvisited bookmark ID should match");
+    strictEqual(
+      tbBmkNode.title,
+      "",
+      "Unvisited bookmark node should not have title"
+    );
+  } finally {
+    node.containerOpen = false;
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_untitled_folder() {
+  let { root: node } = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+
+  try {
+    let folder = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+
+    await PlacesTestUtils.promiseAsyncUpdates();
+
+    let folderId = await PlacesTestUtils.promiseItemId(folder.guid);
+    strictEqual(
+      PlacesUtils.bookmarks.getItemTitle(folderId),
+      "",
+      "Should return empty string for untitled folder"
+    );
+
+    let folderNode = node.getChild(0);
+    equal(folderNode.itemId, folderId, "Folder ID should match");
+    strictEqual(folderNode.title, "", "Folder node should not have title");
+  } finally {
+    node.containerOpen = false;
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/bookmarks/xpcshell.toml b/toolkit/components/places/tests/bookmarks/xpcshell.toml
new file mode 100644
index 0000000000..0b989e5fbf
--- /dev/null
+++ b/toolkit/components/places/tests/bookmarks/xpcshell.toml
@@ -0,0 +1,85 @@
+[DEFAULT]
+head = "head_bookmarks.js"
+skip-if = ["os == 'android'"]
+firefox-appdir = "browser"
+
+["test_1016953-renaming-uncompressed.js"]
+
+["test_1017502-bookmarks_foreign_count.js"]
+
+["test_1129529.js"]
+support-files = ["bookmarks_long_tag.json"]
+
+["test_384228.js"]
+
+["test_385829.js"]
+
+["test_388695.js"]
+
+["test_393498.js"]
+
+["test_405938_restore_queries.js"]
+
+["test_424958-json-quoted-folders.js"]
+
+["test_448584.js"]
+
+["test_458683.js"]
+
+["test_466303-json-remove-backups.js"]
+
+["test_477583_json-backup-in-future.js"]
+
+["test_818584-discard-duplicate-backups.js"]
+
+["test_818587_compress-bookmarks-backups.js"]
+
+["test_818593-store-backup-metadata.js"]
+
+["test_992901-backup-unsorted-hierarchy.js"]
+
+["test_997030-bookmarks-html-encode.js"]
+
+["test_async_observers.js"]
+
+["test_bmindex.js"]
+
+["test_bookmark_observer.js"]
+
+["test_bookmarks_eraseEverything.js"]
+
+["test_bookmarks_fetch.js"]
+
+["test_bookmarks_getRecent.js"]
+
+["test_bookmarks_insert.js"]
+
+["test_bookmarks_insertTree.js"]
+
+["test_bookmarks_moveToFolder.js"]
+
+["test_bookmarks_notifications.js"]
+
+["test_bookmarks_remove.js"]
+
+["test_bookmarks_remove_batch.js"]
+
+["test_bookmarks_reorder.js"]
+
+["test_bookmarks_search.js"]
+
+["test_bookmarks_update.js"]
+
+["test_insertTree_fixupOrSkipInvalidEntries.js"]
+
+["test_keywords.js"]
+
+["test_removeFolderTransaction_reinsert.js"]
+
+["test_savedsearches.js"]
+
+["test_sync_fields.js"]
+
+["test_tags.js"]
+
+["test_untitled.js"]
diff --git a/toolkit/components/places/tests/browser/1601563-1.html b/toolkit/components/places/tests/browser/1601563-1.html
new file mode 100644
index 0000000000..4f92778561
--- /dev/null
+++ b/toolkit/components/places/tests/browser/1601563-1.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<title>First title</title>
+<iframe srcdoc=""></iframe>
+<script>
+onload = function() {
+  // This iframe doc shouldn't override our title.
+  let doc = document.querySelector("iframe").contentDocument;
+  doc.open();
+  doc.write("<title>This is not your title</title>Hello");
+  doc.close();
+
+  if (doc.title == "This is not your title") {
+    // Now navigate away so that the test has something to wait for to ensure the
+    // relevant code has run.
+    let link = document.createElement("a");
+    link.href = window.location.href.replace("-1.html", "-2.html");
+    link.click();
+  }
+}
+</script>
diff --git a/toolkit/components/places/tests/browser/1601563-2.html b/toolkit/components/places/tests/browser/1601563-2.html
new file mode 100644
index 0000000000..b1c000cd5a
--- /dev/null
+++ b/toolkit/components/places/tests/browser/1601563-2.html
@@ -0,0 +1,3 @@
+<!doctype html>
+<title>Second title</title>
+Nothing to see here.
diff --git a/toolkit/components/places/tests/browser/399606-history.go-0.html b/toolkit/components/places/tests/browser/399606-history.go-0.html
new file mode 100644
index 0000000000..6e36aa23de
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-history.go-0.html
@@ -0,0 +1,13 @@
+<html>
+<head>
+<title>history.go(0)</title>
+<script>
+setTimeout(function() {
+  history.go(0);
+}, 1000);
+</script>
+</head>
+<body>
+Testing history.go(0)
+</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/399606-httprefresh.html b/toolkit/components/places/tests/browser/399606-httprefresh.html
new file mode 100644
index 0000000000..e43455ee05
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-httprefresh.html
@@ -0,0 +1,8 @@
+<html><head>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8">
+
+<meta http-equiv="refresh" content="1">
+<title>httprefresh</title>
+</head><body>
+Testing httprefresh
+</body></html>
diff --git a/toolkit/components/places/tests/browser/399606-location.reload.html b/toolkit/components/places/tests/browser/399606-location.reload.html
new file mode 100644
index 0000000000..54eefab1c3
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-location.reload.html
@@ -0,0 +1,13 @@
+<html>
+<head>
+<title>location.reload()</title>
+<script>
+setTimeout(function() {
+  location.reload();
+}, 100);
+</script>
+</head>
+<body>
+Testing location.reload();
+</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/399606-location.replace.html b/toolkit/components/places/tests/browser/399606-location.replace.html
new file mode 100644
index 0000000000..8a72c96722
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-location.replace.html
@@ -0,0 +1,13 @@
+<html>
+<head>
+<title>location.replace</title>
+<script>
+setTimeout(function() {
+  location.replace(window.location.href);
+}, 1000);
+</script>
+</head>
+<body>
+Testing location.replace
+</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/399606-window.location.href.html b/toolkit/components/places/tests/browser/399606-window.location.href.html
new file mode 100644
index 0000000000..490b08e40c
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-window.location.href.html
@@ -0,0 +1,14 @@
+<html>
+<head>
+<title>window.location.href</title>
+<script>
+setTimeout(function() {
+  // eslint-disable-next-line no-self-assign
+  window.location.href = window.location.href;
+}, 1000);
+</script>
+</head>
+<body>
+Testing window.location.href
+</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/399606-window.location.html b/toolkit/components/places/tests/browser/399606-window.location.html
new file mode 100644
index 0000000000..b84366cf8d
--- /dev/null
+++ b/toolkit/components/places/tests/browser/399606-window.location.html
@@ -0,0 +1,14 @@
+<html>
+<head>
+<title>window.location</title>
+<script>
+setTimeout(function() {
+  // eslint-disable-next-line no-self-assign
+  window.location = window.location;
+}, 1000);
+</script>
+</head>
+<body>
+Testing window.location
+</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/461710_link_page-2.html b/toolkit/components/places/tests/browser/461710_link_page-2.html
new file mode 100644
index 0000000000..726373f83e
--- /dev/null
+++ b/toolkit/components/places/tests/browser/461710_link_page-2.html
@@ -0,0 +1,13 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Link page 2</title>
+    <style type="text/css">
+      a:link { color: #0000ff; }
+      a:visited { color: #ff0000; }
+    </style>
+  </head>
+  <body>
+    <p><a href="461710_visited_page.html" id="link">Link to the second visited page</a></p>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/461710_link_page-3.html b/toolkit/components/places/tests/browser/461710_link_page-3.html
new file mode 100644
index 0000000000..d465cf79c6
--- /dev/null
+++ b/toolkit/components/places/tests/browser/461710_link_page-3.html
@@ -0,0 +1,13 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Link page 3</title>
+    <style type="text/css">
+      a:link { color: #0000ff; }
+      a:visited { color: #ff0000; }
+    </style>
+  </head>
+  <body>
+    <p><a href="461710_visited_page.html" id="link">Link to the third visited page</a></p>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/461710_link_page.html b/toolkit/components/places/tests/browser/461710_link_page.html
new file mode 100644
index 0000000000..05189fa41b
--- /dev/null
+++ b/toolkit/components/places/tests/browser/461710_link_page.html
@@ -0,0 +1,13 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Link page</title>
+    <style type="text/css">
+      a:link { color: #0000ff; }
+      a:visited { color: #ff0000; }
+    </style>
+  </head>
+  <body>
+    <p><a href="461710_visited_page.html" id="link">Link to the visited page</a></p>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/461710_visited_page.html b/toolkit/components/places/tests/browser/461710_visited_page.html
new file mode 100644
index 0000000000..3ff52f69c8
--- /dev/null
+++ b/toolkit/components/places/tests/browser/461710_visited_page.html
@@ -0,0 +1,9 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Visited page</title>
+  </head>
+  <body>
+    <p>This page is marked as visited</p>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/begin.html b/toolkit/components/places/tests/browser/begin.html
new file mode 100644
index 0000000000..da4c16dd25
--- /dev/null
+++ b/toolkit/components/places/tests/browser/begin.html
@@ -0,0 +1,10 @@
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+
+<html>
+  <body>
+    <a id="clickme" href="redirect_twice.sjs">Redirect twice</a>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/browser.toml b/toolkit/components/places/tests/browser/browser.toml
new file mode 100644
index 0000000000..022b929240
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser.toml
@@ -0,0 +1,115 @@
+[DEFAULT]
+support-files = ["head.js"]
+
+["browser_bug399606.js"]
+https_first_disabled = true
+support-files = [
+  "399606-history.go-0.html",
+  "399606-httprefresh.html",
+  "399606-location.reload.html",
+  "399606-location.replace.html",
+  "399606-window.location.html",
+  "399606-window.location.href.html",
+]
+
+["browser_bug461710.js"]
+https_first_disabled = true
+support-files = [
+  "461710_link_page-2.html",
+  "461710_link_page-3.html",
+  "461710_link_page.html",
+  "461710_visited_page.html",
+]
+
+["browser_bug646422.js"]
+https_first_disabled = true
+
+["browser_bug680727.js"]
+https_first_disabled = true
+skip-if = ["verify"]
+
+["browser_bug1601563.js"]
+https_first_disabled = true
+support-files = [
+  "1601563-1.html",
+  "1601563-2.html",
+]
+
+["browser_double_redirect.js"]
+https_first_disabled = true
+support-files = [
+  "begin.html",
+  "final.html",
+  "redirect_once.sjs",
+  "redirect_twice.sjs",
+]
+
+["browser_favicon_privatebrowsing_perwindowpb.js"]
+
+["browser_history_post.js"]
+https_first_disabled = true
+support-files = [
+  "history_post.html",
+  "history_post.sjs",
+]
+
+["browser_multi_redirect_frecency.js"]
+https_first_disabled = true
+support-files = [
+  "final.html",
+  "redirect_once.sjs",
+  "redirect_thrice.sjs",
+  "redirect_twice.sjs",
+  "redirect_twice_perma.sjs",
+]
+
+["browser_notfound.js"]
+
+["browser_onvisit_title_null_for_navigation.js"]
+https_first_disabled = true
+skip-if = ["verify"]
+support-files = ["empty_page.html"]
+
+["browser_redirect.js"]
+support-files = [
+  "redirect.sjs",
+  "redirect-target.html",
+]
+
+["browser_redirect_self.js"]
+support-files = ["redirect_self.sjs"]
+
+["browser_settitle.js"]
+https_first_disabled = true
+support-files = [
+  "title1.html",
+  "title2.html",
+]
+
+["browser_upgrade.js"]
+
+["browser_visited_notfound.js"]
+
+["browser_visituri.js"]
+https_first_disabled = true
+support-files = [
+  "begin.html",
+  "final.html",
+  "redirect_once.sjs",
+  "redirect_twice.sjs",
+]
+
+["browser_visituri_nohistory.js"]
+support-files = [
+  "begin.html",
+  "final.html",
+  "favicon-normal16.png",
+  "favicon-normal32.png",
+]
+
+["browser_visituri_privatebrowsing_perwindowpb.js"]
+support-files = [
+  "begin.html",
+  "favicon.html",
+  "final.html",
+]
diff --git a/toolkit/components/places/tests/browser/browser_bug1601563.js b/toolkit/components/places/tests/browser/browser_bug1601563.js
new file mode 100644
index 0000000000..41e278ee54
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_bug1601563.js
@@ -0,0 +1,40 @@
+const PREFIX =
+  "http://example.com/tests/toolkit/components/places/tests/browser/1601563";
+
+function titleUpdate(pageUrl) {
+  let lastTitle = null;
+  return PlacesTestUtils.waitForNotification("page-title-changed", events => {
+    if (pageUrl != events[0].url) {
+      return false;
+    }
+    lastTitle = events[0].title;
+    return true;
+  }).then(() => {
+    return lastTitle;
+  });
+}
+
+add_task(async function () {
+  registerCleanupFunction(PlacesUtils.history.clear);
+  const FIRST_URL = PREFIX + "-1.html";
+  const SECOND_URL = PREFIX + "-2.html";
+  let firstTitlePromise = titleUpdate(FIRST_URL);
+  let secondTitlePromise = titleUpdate(SECOND_URL);
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, FIRST_URL);
+
+  let firstTitle = await firstTitlePromise;
+  is(firstTitle, "First title", "First title should match the page");
+
+  let secondTitle = await secondTitlePromise;
+  is(secondTitle, "Second title", "Second title should match the page");
+
+  let entry = await PlacesUtils.history.fetch(FIRST_URL);
+  is(
+    entry.title,
+    firstTitle,
+    "Should not override first title with document.open()ed frame"
+  );
+
+  await BrowserTestUtils.removeTab(tab);
+});
diff --git a/toolkit/components/places/tests/browser/browser_bug399606.js b/toolkit/components/places/tests/browser/browser_bug399606.js
new file mode 100644
index 0000000000..ace1549c54
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_bug399606.js
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function () {
+  registerCleanupFunction(PlacesUtils.history.clear);
+
+  const URIS = [
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-window.location.href.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-history.go-0.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-location.replace.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-location.reload.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-httprefresh.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/399606-window.location.html",
+  ];
+
+  // Create and add history observer.
+  let count = 0;
+  let expectedURI = null;
+  function onVisitsListener(aEvents) {
+    for (let event of aEvents) {
+      info("Received onVisits: " + event.url);
+      if (event.url == expectedURI) {
+        count++;
+      }
+    }
+  }
+
+  async function promiseLoadedThreeTimes(uri) {
+    count = 0;
+    expectedURI = uri;
+    let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+    PlacesObservers.addListener(["page-visited"], onVisitsListener);
+    BrowserTestUtils.startLoadingURIString(gBrowser, uri);
+    await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser, false, uri);
+    await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser, false, uri);
+    await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser, false, uri);
+    PlacesObservers.removeListener(["page-visited"], onVisitsListener);
+    BrowserTestUtils.removeTab(tab);
+  }
+
+  for (let uri of URIS) {
+    await promiseLoadedThreeTimes(uri);
+    is(
+      count,
+      1,
+      "'page-visited' has been received right number of times for " + uri
+    );
+  }
+});
diff --git a/toolkit/components/places/tests/browser/browser_bug461710.js b/toolkit/components/places/tests/browser/browser_bug461710.js
new file mode 100644
index 0000000000..6815860929
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_bug461710.js
@@ -0,0 +1,89 @@
+const kRed = "rgb(255, 0, 0)";
+const kBlue = "rgb(0, 0, 255)";
+
+const prefix =
+  "http://example.com/tests/toolkit/components/places/tests/browser/461710_";
+
+add_task(async function () {
+  registerCleanupFunction(PlacesUtils.history.clear);
+  let normalWindow = await BrowserTestUtils.openNewBrowserWindow();
+  let privateWindow = await BrowserTestUtils.openNewBrowserWindow({
+    private: true,
+  });
+  let tests = [
+    {
+      private: false,
+      topic: "uri-visit-saved",
+      subtest: "visited_page.html",
+    },
+    {
+      private: false,
+      subtest: "link_page.html",
+      color: kRed,
+      message: "Visited link coloring should work outside of private mode",
+    },
+    {
+      private: true,
+      subtest: "link_page-2.html",
+      color: kBlue,
+      message: "Visited link coloring should not work inside of private mode",
+    },
+    {
+      private: false,
+      subtest: "link_page-3.html",
+      color: kRed,
+      message: "Visited link coloring should work outside of private mode",
+    },
+  ];
+
+  let uri = Services.io.newURI(prefix + tests[0].subtest);
+  for (let test of tests) {
+    info(test.subtest);
+    let promise = null;
+    if (test.topic) {
+      promise = TestUtils.topicObserved(test.topic, subject =>
+        uri.equals(subject.QueryInterface(Ci.nsIURI))
+      );
+    }
+    await BrowserTestUtils.withNewTab(
+      {
+        gBrowser: test.private ? privateWindow.gBrowser : normalWindow.gBrowser,
+        url: prefix + test.subtest,
+      },
+      async function (browser) {
+        if (promise) {
+          await promise;
+        }
+
+        if (test.color) {
+          // In e10s waiting for visited-status-resolution is not enough to ensure links
+          // have been updated, because it only tells us that messages to update links
+          // have been dispatched. We must still wait for the actual links to update.
+          await TestUtils.waitForCondition(async function () {
+            let color = await SpecialPowers.spawn(
+              browser,
+              [],
+              async function () {
+                let elem = content.document.getElementById("link");
+                return content.windowUtils.getVisitedDependentComputedStyle(
+                  elem,
+                  "",
+                  "color"
+                );
+              }
+            );
+            return color == test.color;
+          }, test.message);
+          // The harness will consider the test as failed overall if there were no
+          // passes or failures, so record it as a pass.
+          ok(true, test.message);
+        }
+      }
+    );
+  }
+
+  let promisePBExit = TestUtils.topicObserved("last-pb-context-exited");
+  await BrowserTestUtils.closeWindow(privateWindow);
+  await promisePBExit;
+  await BrowserTestUtils.closeWindow(normalWindow);
+});
diff --git a/toolkit/components/places/tests/browser/browser_bug646422.js b/toolkit/components/places/tests/browser/browser_bug646422.js
new file mode 100644
index 0000000000..cb6512ed4e
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_bug646422.js
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test for Bug 646224.  Make sure that after changing the URI via
+ * history.pushState, the history service has a title stored for the new URI.
+ **/
+
+add_task(async function () {
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "http://example.com"
+  );
+
+  const newTitlePromise = PlacesTestUtils.waitForNotification(
+    "page-title-changed",
+    events => /new_page$/.test(events[0].url)
+  );
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async function () {
+    let title = content.document.title;
+    content.history.pushState("", "", "new_page");
+    Assert.ok(title, "Content window should initially have a title.");
+  });
+
+  const events = await newTitlePromise;
+  const newtitle = events[0].title;
+
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [{ newtitle }],
+    async function (args) {
+      Assert.equal(
+        args.newtitle,
+        content.document.title,
+        "Title after pushstate."
+      );
+    }
+  );
+
+  await PlacesUtils.history.clear();
+  gBrowser.removeTab(tab);
+});
diff --git a/toolkit/components/places/tests/browser/browser_bug680727.js b/toolkit/components/places/tests/browser/browser_bug680727.js
new file mode 100644
index 0000000000..313adb3c75
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_bug680727.js
@@ -0,0 +1,130 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Ensure that clicking the button in the Offline mode neterror page updates
+   global history. See bug 680727. */
+/* TEST_PATH=toolkit/components/places/tests/browser/browser_bug680727.js make -C $(OBJDIR) mochitest-browser-chrome */
+
+const kUniqueURI = Services.io.newURI("http://mochi.test:8888/#bug_680727");
+var proxyPrefValue;
+var ourTab;
+
+function test() {
+  waitForExplicitFinish();
+
+  // Tests always connect to localhost, and per bug 87717, localhost is now
+  // reachable in offline mode.  To avoid this, disable any proxy.
+  proxyPrefValue = Services.prefs.getIntPref("network.proxy.type");
+  Services.prefs.setIntPref("network.proxy.type", 0);
+
+  // Clear network cache.
+  Services.cache2.clear();
+
+  // Go offline, expecting the error page.
+  Services.io.offline = true;
+
+  BrowserTestUtils.openNewForegroundTab(gBrowser).then(tab => {
+    ourTab = tab;
+    BrowserTestUtils.browserLoaded(
+      ourTab.linkedBrowser,
+      false,
+      null,
+      true
+    ).then(errorListener);
+    BrowserTestUtils.startLoadingURIString(
+      ourTab.linkedBrowser,
+      kUniqueURI.spec
+    );
+  });
+}
+
+// ------------------------------------------------------------------------------
+// listen to loading the neterror page. (offline mode)
+function errorListener() {
+  ok(Services.io.offline, "Services.io.offline is true.");
+
+  // This is an error page.
+  SpecialPowers.spawn(ourTab.linkedBrowser, [kUniqueURI.spec], function (uri) {
+    Assert.equal(
+      content.document.documentURI.substring(0, 27),
+      "about:neterror?e=netOffline",
+      "Document URI is the error page."
+    );
+
+    // But location bar should show the original request.
+    Assert.equal(
+      content.location.href,
+      uri,
+      "Docshell URI is the original URI."
+    );
+  }).then(() => {
+    // Global history does not record URI of a failed request.
+    PlacesTestUtils.promiseAsyncUpdates().then(() => {
+      PlacesUtils.history.hasVisits(kUniqueURI).then(isVisited => {
+        errorAsyncListener(kUniqueURI, isVisited);
+      });
+    });
+  });
+}
+
+function errorAsyncListener(aURI, aIsVisited) {
+  ok(
+    kUniqueURI.equals(aURI) && !aIsVisited,
+    "The neterror page is not listed in global history."
+  );
+
+  Services.prefs.setIntPref("network.proxy.type", proxyPrefValue);
+
+  // Now press the "Try Again" button, with offline mode off.
+  Services.io.offline = false;
+
+  BrowserTestUtils.browserLoaded(ourTab.linkedBrowser, false, null, true).then(
+    reloadListener
+  );
+
+  SpecialPowers.spawn(ourTab.linkedBrowser, [], function () {
+    Assert.ok(
+      content.document.querySelector("#netErrorButtonContainer > .try-again"),
+      "The error page has got a .try-again element"
+    );
+    content.document
+      .querySelector("#netErrorButtonContainer > .try-again")
+      .click();
+  });
+}
+
+// ------------------------------------------------------------------------------
+// listen to reload of neterror.
+function reloadListener() {
+  // This listener catches "DOMContentLoaded" on being called
+  // nsIWPL::onLocationChange(...). That is right *AFTER*
+  // IHistory::VisitURI(...) is called.
+  ok(!Services.io.offline, "Services.io.offline is false.");
+
+  SpecialPowers.spawn(ourTab.linkedBrowser, [kUniqueURI.spec], function (uri) {
+    // This is not an error page.
+    Assert.equal(
+      content.document.documentURI,
+      uri,
+      "Document URI is not the offline-error page, but the original URI."
+    );
+  }).then(() => {
+    // Check if global history remembers the successfully-requested URI.
+    PlacesTestUtils.promiseAsyncUpdates().then(() => {
+      PlacesUtils.history.hasVisits(kUniqueURI).then(isVisited => {
+        reloadAsyncListener(kUniqueURI, isVisited);
+      });
+    });
+  });
+}
+
+function reloadAsyncListener(aURI, aIsVisited) {
+  ok(kUniqueURI.equals(aURI) && aIsVisited, "We have visited the URI.");
+  PlacesUtils.history.clear().then(finish);
+}
+
+registerCleanupFunction(async function () {
+  Services.prefs.setIntPref("network.proxy.type", proxyPrefValue);
+  Services.io.offline = false;
+  BrowserTestUtils.removeTab(ourTab);
+});
diff --git a/toolkit/components/places/tests/browser/browser_double_redirect.js b/toolkit/components/places/tests/browser/browser_double_redirect.js
new file mode 100644
index 0000000000..435bd86f19
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_double_redirect.js
@@ -0,0 +1,83 @@
+// Test for bug 411966.
+// When a page redirects multiple times, from_visit should point to the
+// previous visit in the chain, not to the first visit in the chain.
+
+add_task(async function () {
+  await PlacesUtils.history.clear();
+
+  const BASE_URL =
+    "http://example.com/tests/toolkit/components/places/tests/browser/";
+  const TEST_URI = NetUtil.newURI(BASE_URL + "begin.html");
+  const FIRST_REDIRECTING_URI = NetUtil.newURI(BASE_URL + "redirect_twice.sjs");
+  const FINAL_URI = NetUtil.newURI(
+    "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html"
+  );
+
+  let promiseVisits = new Promise(resolve => {
+    let observer = {
+      _notified: [],
+      onVisit(uri, id, time, referrerId, transition) {
+        info("Received onVisit: " + uri);
+        this._notified.push(uri);
+
+        if (uri != FINAL_URI.spec) {
+          return;
+        }
+
+        is(this._notified.length, 4);
+        PlacesObservers.removeListener(["page-visited"], this.handleEvents);
+
+        (async function () {
+          // Get all pages visited from the original typed one
+          let db = await PlacesUtils.promiseDBConnection();
+          let rows = await db.execute(
+            `SELECT url FROM moz_historyvisits
+             JOIN moz_places h ON h.id = place_id
+             WHERE from_visit IN
+                (SELECT v.id FROM moz_historyvisits v
+                 JOIN moz_places p ON p.id = v.place_id
+                 WHERE p.url_hash = hash(:url) AND p.url = :url)
+            `,
+            { url: TEST_URI.spec }
+          );
+
+          is(rows.length, 1, "Found right number of visits");
+          let visitedUrl = rows[0].getResultByName("url");
+          // Check that redirect from_visit is not from the original typed one
+          is(
+            visitedUrl,
+            FIRST_REDIRECTING_URI.spec,
+            "Check referrer for " + visitedUrl
+          );
+
+          resolve();
+        })();
+      },
+      handleEvents(events) {
+        is(events.length, 1, "Right number of visits notified");
+        is(events[0].type, "page-visited");
+        let { url, visitId, visitTime, referringVisitId, transitionType } =
+          events[0];
+        this.onVisit(url, visitId, visitTime, referringVisitId, transitionType);
+      },
+    };
+    observer.handleEvents = observer.handleEvents.bind(observer);
+    PlacesObservers.addListener(["page-visited"], observer.handleEvents);
+  });
+
+  PlacesUtils.history.markPageAsTyped(TEST_URI);
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: TEST_URI.spec,
+    },
+    async function (browser) {
+      // Load begin page, click link on page to record visits.
+      await BrowserTestUtils.synthesizeMouseAtCenter("#clickme", {}, browser);
+
+      await promiseVisits;
+    }
+  );
+
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/browser/browser_favicon_privatebrowsing_perwindowpb.js b/toolkit/components/places/tests/browser/browser_favicon_privatebrowsing_perwindowpb.js
new file mode 100644
index 0000000000..ab3e0a1ef1
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_favicon_privatebrowsing_perwindowpb.js
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function test() {
+  waitForExplicitFinish();
+
+  const pageURI =
+    "http://example.org/tests/toolkit/components/places/tests/browser/favicon.html";
+  let windowsToClose = [];
+
+  registerCleanupFunction(function () {
+    windowsToClose.forEach(function (aWin) {
+      aWin.close();
+    });
+  });
+
+  function testOnWindow(aIsPrivate, aCallback) {
+    whenNewWindowLoaded({ private: aIsPrivate }, function (aWin) {
+      windowsToClose.push(aWin);
+      executeSoon(() => aCallback(aWin));
+    });
+  }
+
+  function waitForTabLoad(aWin, aCallback) {
+    BrowserTestUtils.browserLoaded(aWin.gBrowser.selectedBrowser).then(
+      aCallback
+    );
+    BrowserTestUtils.startLoadingURIString(
+      aWin.gBrowser.selectedBrowser,
+      pageURI
+    );
+  }
+
+  testOnWindow(true, function (win) {
+    waitForTabLoad(win, function () {
+      PlacesUtils.favicons.getFaviconURLForPage(
+        NetUtil.newURI(pageURI),
+        function (uri, dataLen, data, mimeType) {
+          is(uri, null, "No result should be found");
+          finish();
+        }
+      );
+    });
+  });
+}
diff --git a/toolkit/components/places/tests/browser/browser_history_post.js b/toolkit/components/places/tests/browser/browser_history_post.js
new file mode 100644
index 0000000000..a62592516f
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_history_post.js
@@ -0,0 +1,35 @@
+const PAGE_URI =
+  "http://example.com/tests/toolkit/components/places/tests/browser/history_post.html";
+const SJS_URI = NetUtil.newURI(
+  "http://example.com/tests/toolkit/components/places/tests/browser/history_post.sjs"
+);
+
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: PAGE_URI },
+    async function (aBrowser) {
+      await SpecialPowers.spawn(aBrowser, [], async function () {
+        let doc = content.document;
+        let submit = doc.getElementById("submit");
+        let iframe = doc.getElementById("post_iframe");
+        let p = new Promise((resolve, reject) => {
+          iframe.addEventListener(
+            "load",
+            function () {
+              resolve();
+            },
+            { once: true }
+          );
+        });
+        submit.click();
+        await p;
+      });
+      let visited = await PlacesUtils.history.hasVisits(SJS_URI);
+      ok(!visited, "The POST page should not be added to history");
+      ok(
+        !(await PlacesTestUtils.isPageInDB(SJS_URI.spec)),
+        "The page should not be in the database"
+      );
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_multi_redirect_frecency.js b/toolkit/components/places/tests/browser/browser_multi_redirect_frecency.js
new file mode 100644
index 0000000000..a406422a2f
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_multi_redirect_frecency.js
@@ -0,0 +1,177 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const ROOT_URI =
+  "http://mochi.test:8888/tests/toolkit/components/places/tests/browser/";
+const REDIRECT_URI = Services.io.newURI(ROOT_URI + "redirect_thrice.sjs");
+const INTERMEDIATE_URI_1 = Services.io.newURI(
+  ROOT_URI + "redirect_twice_perma.sjs"
+);
+const INTERMEDIATE_URI_2 = Services.io.newURI(ROOT_URI + "redirect_once.sjs");
+const TARGET_URI = Services.io.newURI(
+  "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html"
+);
+
+const REDIRECT_SOURCE_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.redirectSourceVisitBonus"
+);
+const PERM_REDIRECT_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.permRedirectVisitBonus"
+);
+const TYPED_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.typedVisitBonus"
+);
+
+// Ensure that decay frecency doesn't kick in during tests (as a result
+// of idle-daily).
+Services.prefs.setCharPref("places.frecency.decayRate", "1.0");
+
+registerCleanupFunction(async function () {
+  Services.prefs.clearUserPref("places.frecency.decayRate");
+  await PlacesUtils.history.clear();
+});
+
+async function check_uri(uri, frecency, hidden) {
+  is(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: uri,
+    }),
+    frecency,
+    "Frecency of the page is the expected one"
+  );
+  is(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", {
+      url: uri,
+    }),
+    hidden,
+    "Hidden value of the page is the expected one"
+  );
+}
+
+async function waitVisitedNotifications() {
+  let redirectNotified = false;
+  await PlacesTestUtils.waitForNotification("page-visited", visits => {
+    is(visits.length, 1, "Was notified for the right number of visits.");
+    let { url } = visits[0];
+    info("Received 'page-visited': " + url);
+    if (url == REDIRECT_URI.spec) {
+      redirectNotified = true;
+    }
+    return url == TARGET_URI.spec;
+  });
+  return redirectNotified;
+}
+
+let firstRedirectBonus = 0;
+let nextRedirectBonus = 0;
+let targetBonus = 0;
+
+add_task(async function test_multiple_redirect() {
+  // The redirect source bonus overrides the link bonus.
+  let visitedPromise = waitVisitedNotifications();
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: REDIRECT_URI.spec,
+    },
+    async function () {
+      info("Waiting for onVisits");
+      let redirectNotified = await visitedPromise;
+      ok(redirectNotified, "The redirect should have been notified");
+
+      firstRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(REDIRECT_URI, firstRedirectBonus, 1);
+      nextRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(INTERMEDIATE_URI_1, nextRedirectBonus, 1);
+      await check_uri(INTERMEDIATE_URI_2, nextRedirectBonus, 1);
+      // TODO Bug 487813 - This should be TYPED_VISIT_BONUS, however as we don't
+      // currently track redirects across multiple redirects, we fallback to the
+      // PERM_REDIRECT_VISIT_BONUS.
+      targetBonus += PERM_REDIRECT_VISIT_BONUS;
+      await check_uri(TARGET_URI, targetBonus, 0);
+    }
+  );
+});
+
+add_task(async function test_multiple_redirect_typed() {
+  // The typed bonus wins because the redirect is permanent.
+  PlacesUtils.history.markPageAsTyped(REDIRECT_URI);
+  let visitedPromise = waitVisitedNotifications();
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: REDIRECT_URI.spec,
+    },
+    async function () {
+      info("Waiting for onVisits");
+      let redirectNotified = await visitedPromise;
+      ok(redirectNotified, "The redirect should have been notified");
+
+      firstRedirectBonus += TYPED_VISIT_BONUS;
+      await check_uri(REDIRECT_URI, firstRedirectBonus, 1);
+      nextRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(INTERMEDIATE_URI_1, nextRedirectBonus, 1);
+      await check_uri(INTERMEDIATE_URI_2, nextRedirectBonus, 1);
+      // TODO Bug 487813 - This should be TYPED_VISIT_BONUS, however as we don't
+      // currently track redirects across multiple redirects, we fallback to the
+      // PERM_REDIRECT_VISIT_BONUS.
+      targetBonus += PERM_REDIRECT_VISIT_BONUS;
+      await check_uri(TARGET_URI, targetBonus, 0);
+    }
+  );
+});
+
+add_task(async function test_second_typed_visit() {
+  // The typed bonus wins because the redirect is permanent.
+  PlacesUtils.history.markPageAsTyped(REDIRECT_URI);
+  let visitedPromise = waitVisitedNotifications();
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: REDIRECT_URI.spec,
+    },
+    async function () {
+      info("Waiting for onVisits");
+      let redirectNotified = await visitedPromise;
+      ok(redirectNotified, "The redirect should have been notified");
+
+      firstRedirectBonus += TYPED_VISIT_BONUS;
+      await check_uri(REDIRECT_URI, firstRedirectBonus, 1);
+      nextRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(INTERMEDIATE_URI_1, nextRedirectBonus, 1);
+      await check_uri(INTERMEDIATE_URI_2, nextRedirectBonus, 1);
+      // TODO Bug 487813 - This should be TYPED_VISIT_BONUS, however as we don't
+      // currently track redirects across multiple redirects, we fallback to the
+      // PERM_REDIRECT_VISIT_BONUS.
+      targetBonus += PERM_REDIRECT_VISIT_BONUS;
+      await check_uri(TARGET_URI, targetBonus, 0);
+    }
+  );
+});
+
+add_task(async function test_subsequent_link_visit() {
+  // Another non typed visit.
+  let visitedPromise = waitVisitedNotifications();
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: REDIRECT_URI.spec,
+    },
+    async function () {
+      info("Waiting for onVisits");
+      let redirectNotified = await visitedPromise;
+      ok(redirectNotified, "The redirect should have been notified");
+
+      firstRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(REDIRECT_URI, firstRedirectBonus, 1);
+      nextRedirectBonus += REDIRECT_SOURCE_VISIT_BONUS;
+      await check_uri(INTERMEDIATE_URI_1, nextRedirectBonus, 1);
+      await check_uri(INTERMEDIATE_URI_2, nextRedirectBonus, 1);
+      // TODO Bug 487813 - This should be TYPED_VISIT_BONUS, however as we don't
+      // currently track redirects across multiple redirects, we fallback to the
+      // PERM_REDIRECT_VISIT_BONUS.
+      targetBonus += PERM_REDIRECT_VISIT_BONUS;
+      await check_uri(TARGET_URI, targetBonus, 0);
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_notfound.js b/toolkit/components/places/tests/browser/browser_notfound.js
new file mode 100644
index 0000000000..22ac67de0a
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_notfound.js
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function () {
+  const url = "http://mochi.test:8888/notFoundPage.html";
+
+  await registerCleanupFunction(PlacesUtils.history.clear);
+
+  // Used to verify errors are not marked as typed.
+  PlacesUtils.history.markPageAsTyped(NetUtil.newURI(url));
+
+  let promiseVisited = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    events => {
+      console.log(JSON.stringify(events));
+      return events.length == 1 && events[0].url === url;
+    }
+  );
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url,
+    },
+    async browser => {
+      info("awaiting for the visit");
+      await promiseVisited;
+
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+          url,
+        }),
+        0,
+        "Frecency should be 0"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", { url }),
+        0,
+        "Page should not be hidden"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "typed", { url }),
+        0,
+        "page should not be marked as typed"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue(
+          "moz_places",
+          "recalc_frecency",
+          { url }
+        ),
+        0,
+        "page should not be marked for frecency recalculation"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue(
+          "moz_places",
+          "recalc_alt_frecency",
+          { url }
+        ),
+        0,
+        "page should not be marked for alt frecency recalculation"
+      );
+
+      info("Adding new valid visits should cause recalculation");
+      await PlacesTestUtils.addVisits([url, "https://othersite.org/"]);
+      let frecency = await PlacesTestUtils.getDatabaseValue(
+        "moz_places",
+        "frecency",
+        { url }
+      );
+      Assert.greater(frecency, 0, "Check frecency was updated");
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_onvisit_title_null_for_navigation.js b/toolkit/components/places/tests/browser/browser_onvisit_title_null_for_navigation.js
new file mode 100644
index 0000000000..a7c583975a
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_onvisit_title_null_for_navigation.js
@@ -0,0 +1,41 @@
+const TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "http://example.com"
+);
+
+add_task(async function checkTitleNotificationForNavigation() {
+  const EXPECTED_URL = Services.io.newURI(TEST_PATH + "empty_page.html");
+
+  const promiseVisit = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    events => events[0].url === EXPECTED_URL.spec
+  );
+
+  const promiseTitle = PlacesTestUtils.waitForNotification(
+    "page-title-changed",
+    events => events[0].url === EXPECTED_URL.spec
+  );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    EXPECTED_URL.spec
+  );
+
+  const visitEvents = await promiseVisit;
+  Assert.equal(visitEvents.length, 1, "Right number of visits notified");
+  Assert.equal(visitEvents[0].type, "page-visited");
+  info("'page-visited': " + visitEvents[0].url);
+  Assert.equal(visitEvents[0].lastKnownTitle, null, "Should not have a title");
+
+  const titleEvents = await promiseTitle;
+  Assert.equal(titleEvents.length, 1, "Right number of title changed notified");
+  Assert.equal(titleEvents[0].type, "page-title-changed");
+  info("'page-title-changed': " + titleEvents[0].url);
+  Assert.equal(
+    titleEvents[0].title,
+    "I am an empty page",
+    "Should have correct title in titlechanged notification"
+  );
+
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/toolkit/components/places/tests/browser/browser_redirect.js b/toolkit/components/places/tests/browser/browser_redirect.js
new file mode 100644
index 0000000000..912b817ad1
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_redirect.js
@@ -0,0 +1,149 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const ROOT_URI =
+  "http://mochi.test:8888/tests/toolkit/components/places/tests/browser/";
+const REDIRECT_URI = Services.io.newURI(ROOT_URI + "redirect.sjs");
+const TARGET_URI = Services.io.newURI(ROOT_URI + "redirect-target.html");
+
+const REDIRECT_SOURCE_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.redirectSourceVisitBonus"
+);
+const LINK_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.linkVisitBonus"
+);
+const TYPED_VISIT_BONUS = Services.prefs.getIntPref(
+  "places.frecency.typedVisitBonus"
+);
+
+// Ensure that decay frecency doesn't kick in during tests (as a result
+// of idle-daily).
+Services.prefs.setCharPref("places.frecency.decayRate", "1.0");
+
+registerCleanupFunction(async function () {
+  Services.prefs.clearUserPref("places.frecency.decayRate");
+  await PlacesUtils.history.clear();
+});
+
+let redirectSourceFrecency = 0;
+let redirectTargetFrecency = 0;
+
+async function check_uri(uri, frecency, hidden) {
+  is(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: uri,
+    }),
+    frecency,
+    "Frecency of the page is the expected one"
+  );
+  is(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", {
+      url: uri,
+    }),
+    hidden,
+    "Hidden value of the page is the expected one"
+  );
+}
+
+add_task(async function redirect_check_new_typed_visit() {
+  // Used to verify the redirect bonus overrides the typed bonus.
+  PlacesUtils.history.markPageAsTyped(REDIRECT_URI);
+
+  redirectSourceFrecency += REDIRECT_SOURCE_VISIT_BONUS;
+  redirectTargetFrecency += TYPED_VISIT_BONUS;
+  let redirectNotified = false;
+
+  let visitedPromise = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    visits => {
+      is(visits.length, 1, "Was notified for the right number of visits.");
+      let { url } = visits[0];
+      info("Received 'page-visited': " + url);
+      if (url == REDIRECT_URI.spec) {
+        redirectNotified = true;
+      }
+      return url == TARGET_URI.spec;
+    }
+  );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    REDIRECT_URI.spec
+  );
+  info("Waiting for onVisits");
+  await visitedPromise;
+  ok(redirectNotified, "The redirect should have been notified");
+
+  await check_uri(REDIRECT_URI, redirectSourceFrecency, 1);
+  await check_uri(TARGET_URI, redirectTargetFrecency, 0);
+
+  BrowserTestUtils.removeTab(tab);
+});
+
+add_task(async function redirect_check_second_typed_visit() {
+  // A second visit with a typed url.
+  PlacesUtils.history.markPageAsTyped(REDIRECT_URI);
+
+  redirectSourceFrecency += REDIRECT_SOURCE_VISIT_BONUS;
+  redirectTargetFrecency += TYPED_VISIT_BONUS;
+  let redirectNotified = false;
+
+  let visitedPromise = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    visits => {
+      is(visits.length, 1, "Was notified for the right number of visits.");
+      let { url } = visits[0];
+      info("Received 'page-visited': " + url);
+      if (url == REDIRECT_URI.spec) {
+        redirectNotified = true;
+      }
+      return url == TARGET_URI.spec;
+    }
+  );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    REDIRECT_URI.spec
+  );
+  info("Waiting for onVisits");
+  await visitedPromise;
+  ok(redirectNotified, "The redirect should have been notified");
+
+  await check_uri(REDIRECT_URI, redirectSourceFrecency, 1);
+  await check_uri(TARGET_URI, redirectTargetFrecency, 0);
+
+  BrowserTestUtils.removeTab(tab);
+});
+
+add_task(async function redirect_check_subsequent_link_visit() {
+  // Another visit, but this time as a visited url.
+  redirectSourceFrecency += REDIRECT_SOURCE_VISIT_BONUS;
+  redirectTargetFrecency += LINK_VISIT_BONUS;
+  let redirectNotified = false;
+
+  let visitedPromise = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    visits => {
+      is(visits.length, 1, "Was notified for the right number of visits.");
+      let { url } = visits[0];
+      info("Received 'page-visited': " + url);
+      if (url == REDIRECT_URI.spec) {
+        redirectNotified = true;
+      }
+      return url == TARGET_URI.spec;
+    }
+  );
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    REDIRECT_URI.spec
+  );
+  info("Waiting for onVisits");
+  await visitedPromise;
+  ok(redirectNotified, "The redirect should have been notified");
+
+  await check_uri(REDIRECT_URI, redirectSourceFrecency, 1);
+  await check_uri(TARGET_URI, redirectTargetFrecency, 0);
+
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/toolkit/components/places/tests/browser/browser_redirect_self.js b/toolkit/components/places/tests/browser/browser_redirect_self.js
new file mode 100644
index 0000000000..7ed7ee0af0
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_redirect_self.js
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Tests a page that redirects to itself. On the initial visit the page should
+ * be marked as hidden, but then the second visit should unhide it.
+ * This ensures that that the history anti-flooding system doesn't skip the
+ * second visit.
+ */
+
+add_task(async function () {
+  await PlacesUtils.history.clear();
+  Cc["@mozilla.org/browser/history;1"]
+    .getService(Ci.mozIAsyncHistory)
+    .clearCache();
+  const url =
+    "http://mochi.test:8888/tests/toolkit/components/places/tests/browser/redirect_self.sjs";
+  let visitCount = 0;
+  function onVisitsListener(events) {
+    visitCount++;
+    Assert.equal(events.length, 1, "Right number of visits notified");
+    Assert.equal(events[0].url, url, "Got a visit for the expected url");
+    if (visitCount == 1) {
+      Assert.ok(events[0].hidden, "The visit should be hidden");
+    } else {
+      Assert.ok(!events[0].hidden, "The visit should not be hidden");
+    }
+  }
+  PlacesObservers.addListener(["page-visited"], onVisitsListener);
+  registerCleanupFunction(async function () {
+    PlacesObservers.removeListener(["page-visited"], onVisitsListener);
+    await PlacesUtils.history.clear();
+  });
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url,
+    },
+    async browser => {
+      await TestUtils.waitForCondition(() => visitCount == 2);
+      // Check that the visit is not hidden in the database.
+      Assert.ok(
+        !(await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", {
+          url,
+        })),
+        "The url should not be hidden in the database"
+      );
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_settitle.js b/toolkit/components/places/tests/browser/browser_settitle.js
new file mode 100644
index 0000000000..3bd5e5f3e6
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_settitle.js
@@ -0,0 +1,48 @@
+var conn = PlacesUtils.history.DBConnection;
+
+/**
+ * Gets a single column value from either the places or historyvisits table.
+ */
+function getColumn(table, column, url) {
+  var stmt = conn.createStatement(
+    `SELECT ${column} FROM ${table} WHERE url_hash = hash(:val) AND url = :val`
+  );
+  try {
+    stmt.params.val = url;
+    stmt.executeStep();
+    return stmt.row[column];
+  } finally {
+    stmt.finalize();
+  }
+}
+
+add_task(async function () {
+  // Make sure titles are correctly saved for a URI with the proper
+  // notifications.
+  const titleChangedPromise =
+    PlacesTestUtils.waitForNotification("page-title-changed");
+
+  const url1 =
+    "http://example.com/tests/toolkit/components/places/tests/browser/title1.html";
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, url1);
+
+  const url2 =
+    "http://example.com/tests/toolkit/components/places/tests/browser/title2.html";
+  let loadPromise = BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser);
+  BrowserTestUtils.startLoadingURIString(gBrowser.selectedBrowser, url2);
+  await loadPromise;
+
+  const events = await titleChangedPromise;
+  is(
+    events[0].url,
+    "http://example.com/tests/toolkit/components/places/tests/browser/title2.html"
+  );
+  is(events[0].title, "Some title");
+  is(events[0].pageGuid, getColumn("moz_places", "guid", events[0].url));
+
+  const title = getColumn("moz_places", "title", events[0].url);
+  is(title, events[0].title);
+
+  gBrowser.removeCurrentTab();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/browser/browser_upgrade.js b/toolkit/components/places/tests/browser/browser_upgrade.js
new file mode 100644
index 0000000000..a5077a345b
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_upgrade.js
@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* eslint-disable @microsoft/sdl/no-insecure-url */
+
+"use strict";
+
+// This test checks that when a upgrade is happening through HTTPS-Only,
+// only a history entry for the https url of the site is added visibly for
+// the user, while the http version gets added as a hidden entry.
+
+async function assertIsPlaceHidden(url, expectHidden) {
+  const hidden = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "hidden",
+    { url }
+  );
+  Assert.ok(hidden !== undefined, `We should have saved a visit to ${url}`);
+  Assert.equal(
+    hidden,
+    expectHidden ? 1 : 0,
+    `Check if the visit to ${url} is hidden`
+  );
+}
+
+async function assertVisitFromAndType(
+  url,
+  expectedFromVisitURL,
+  expectedVisitType
+) {
+  const db = await PlacesUtils.promiseDBConnection();
+  const rows = await db.execute(
+    `SELECT v1.visit_type FROM moz_historyvisits v1
+     JOIN moz_places p1 ON p1.id = v1.place_id
+     WHERE p1.url = :url
+     AND from_visit IN
+       (SELECT v2.id FROM moz_historyvisits v2
+        JOIN moz_places p2 ON p2.id = v2.place_id
+        WHERE p2.url = :expectedFromVisitURL)
+    `,
+    { url, expectedFromVisitURL }
+  );
+  Assert.equal(
+    rows.length,
+    1,
+    `There should be a single visit to ${url} with "from_visit" set to the visit id of ${expectedFromVisitURL}`
+  );
+  Assert.equal(
+    rows[0].getResultByName("visit_type"),
+    expectedVisitType,
+    `The visit to ${url} should have a visit type of ${expectedVisitType}`
+  );
+}
+
+function waitForVisitNotifications(urls) {
+  return Promise.all(
+    urls.map(url =>
+      PlacesTestUtils.waitForNotification("page-visited", events =>
+        events.some(e => e.url === url)
+      )
+    )
+  );
+}
+
+add_task(async function test_upgrade() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.security.https_only_mode", true]],
+  });
+
+  await PlacesUtils.history.clear();
+
+  registerCleanupFunction(async function () {
+    await PlacesUtils.history.clear();
+  });
+
+  const visitPromise = waitForVisitNotifications([
+    "http://example.com/",
+    "https://example.com/",
+  ]);
+
+  info("Opening http://example.com/");
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: "http://example.com/",
+      waitForLoad: true,
+    },
+    async browser => {
+      Assert.equal(
+        browser.currentURI.scheme,
+        "https",
+        "We should have been upgraded"
+      );
+      info("Waiting for page visits to reach places database");
+      await visitPromise;
+      info("Checking places database");
+      await assertIsPlaceHidden("http://example.com/", true);
+      await assertIsPlaceHidden("https://example.com/", false);
+      await assertVisitFromAndType(
+        "https://example.com/",
+        "http://example.com/",
+        Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT
+      );
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_visited_notfound.js b/toolkit/components/places/tests/browser/browser_visited_notfound.js
new file mode 100644
index 0000000000..36d1764361
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_visited_notfound.js
@@ -0,0 +1,76 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test() {
+  const url = "http://mochi.test:8888/notFoundPage.html";
+
+  // Ensure that decay frecency doesn't kick in during tests (as a result
+  // of idle-daily).
+  await SpecialPowers.pushPrefEnv({
+    set: [["places.frecency.decayRate", "1.0"]],
+  });
+  await registerCleanupFunction(PlacesUtils.history.clear);
+
+  // First add a visit to the page, this will ensure that later we skip
+  // updating the frecency for a newly not-found page.
+  await PlacesTestUtils.addVisits(url);
+  let frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url }
+  );
+  Assert.equal(frecency, 100, "Check initial frecency");
+
+  // Used to verify errors are not marked as typed.
+  PlacesUtils.history.markPageAsTyped(NetUtil.newURI(url));
+
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url,
+    },
+    async browser => {
+      info("awaiting for the visit");
+
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+          url,
+        }),
+        frecency,
+        "Frecency should be unchanged"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", {
+          url,
+        }),
+        0,
+        "Page should not be hidden"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue("moz_places", "typed", {
+          url,
+        }),
+        0,
+        "page should not be marked as typed"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue(
+          "moz_places",
+          "recalc_frecency",
+          { url }
+        ),
+        0,
+        "page should not be marked for frecency recalculation"
+      );
+      Assert.equal(
+        await PlacesTestUtils.getDatabaseValue(
+          "moz_places",
+          "recalc_alt_frecency",
+          { url }
+        ),
+        0,
+        "page should not be marked for alt frecency recalculation"
+      );
+    }
+  );
+});
diff --git a/toolkit/components/places/tests/browser/browser_visituri.js b/toolkit/components/places/tests/browser/browser_visituri.js
new file mode 100644
index 0000000000..6633ac188b
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_visituri.js
@@ -0,0 +1,100 @@
+/**
+ * One-time observer callback.
+ */
+function promiseObserve(name, checkFn) {
+  return new Promise(resolve => {
+    Services.obs.addObserver(function observer(subject) {
+      if (checkFn(subject)) {
+        Services.obs.removeObserver(observer, name);
+        resolve();
+      }
+    }, name);
+  });
+}
+
+var conn = PlacesUtils.history.DBConnection;
+
+/**
+ * Gets a single column value from either the places or historyvisits table.
+ */
+function getColumn(table, column, fromColumnName, fromColumnValue) {
+  let sql = `SELECT ${column}
+             FROM ${table}
+             WHERE ${fromColumnName} = :val
+             ${fromColumnName == "url" ? "AND url_hash = hash(:val)" : ""}
+             LIMIT 1`;
+  let stmt = conn.createStatement(sql);
+  try {
+    stmt.params.val = fromColumnValue;
+    ok(stmt.executeStep(), "Expect to get a row");
+    return stmt.row[column];
+  } finally {
+    stmt.reset();
+  }
+}
+
+add_task(async function () {
+  // Make sure places visit chains are saved correctly with a redirect
+  // transitions.
+
+  // Part 1: observe history events that fire when a visit occurs.
+  // Make sure visits appear in order, and that the visit chain is correct.
+  var expectedUrls = [
+    "http://example.com/tests/toolkit/components/places/tests/browser/begin.html",
+    "http://example.com/tests/toolkit/components/places/tests/browser/redirect_twice.sjs",
+    "http://example.com/tests/toolkit/components/places/tests/browser/redirect_once.sjs",
+    "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html",
+  ];
+  var currentIndex = 0;
+
+  function checkObserver(subject) {
+    var uri = subject.QueryInterface(Ci.nsIURI);
+    var expected = expectedUrls[currentIndex];
+    is(uri.spec, expected, "Saved URL visit " + uri.spec);
+
+    var placeId = getColumn("moz_places", "id", "url", uri.spec);
+    var fromVisitId = getColumn(
+      "moz_historyvisits",
+      "from_visit",
+      "place_id",
+      placeId
+    );
+
+    if (currentIndex == 0) {
+      is(fromVisitId, 0, "First visit has no from visit");
+    } else {
+      var lastVisitId = getColumn(
+        "moz_historyvisits",
+        "place_id",
+        "id",
+        fromVisitId
+      );
+      var fromVisitUrl = getColumn("moz_places", "url", "id", lastVisitId);
+      is(
+        fromVisitUrl,
+        expectedUrls[currentIndex - 1],
+        "From visit was " + expectedUrls[currentIndex - 1]
+      );
+    }
+
+    currentIndex++;
+    return currentIndex >= expectedUrls.length;
+  }
+  let visitUriPromise = promiseObserve("uri-visit-saved", checkObserver);
+
+  const testUrl =
+    "http://example.com/tests/toolkit/components/places/tests/browser/begin.html";
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, testUrl);
+
+  // Load begin page, click link on page to record visits.
+  await BrowserTestUtils.synthesizeMouseAtCenter(
+    "#clickme",
+    {},
+    gBrowser.selectedBrowser
+  );
+  await visitUriPromise;
+
+  await PlacesUtils.history.clear();
+
+  gBrowser.removeCurrentTab();
+});
diff --git a/toolkit/components/places/tests/browser/browser_visituri_nohistory.js b/toolkit/components/places/tests/browser/browser_visituri_nohistory.js
new file mode 100644
index 0000000000..9db436b7ac
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_visituri_nohistory.js
@@ -0,0 +1,44 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+const INITIAL_URL =
+  "http://example.com/tests/toolkit/components/places/tests/browser/begin.html";
+const FINAL_URL =
+  "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html";
+
+/**
+ * One-time observer callback.
+ */
+function promiseObserve(name) {
+  return new Promise(resolve => {
+    Services.obs.addObserver(function observer(subject) {
+      Services.obs.removeObserver(observer, name);
+      resolve(subject);
+    }, name);
+  });
+}
+
+add_task(async function () {
+  await SpecialPowers.pushPrefEnv({ set: [["places.history.enabled", false]] });
+
+  let visitUriPromise = promiseObserve("uri-visit-saved");
+
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, INITIAL_URL);
+
+  await SpecialPowers.popPrefEnv();
+
+  let browserLoadedPromise = BrowserTestUtils.browserLoaded(
+    gBrowser.selectedBrowser
+  );
+  BrowserTestUtils.startLoadingURIString(gBrowser, FINAL_URL);
+  await browserLoadedPromise;
+
+  let subject = await visitUriPromise;
+  let uri = subject.QueryInterface(Ci.nsIURI);
+  is(uri.spec, FINAL_URL, "received expected visit");
+
+  await PlacesUtils.history.clear();
+  gBrowser.removeCurrentTab();
+});
diff --git a/toolkit/components/places/tests/browser/browser_visituri_privatebrowsing_perwindowpb.js b/toolkit/components/places/tests/browser/browser_visituri_privatebrowsing_perwindowpb.js
new file mode 100644
index 0000000000..746611d2ad
--- /dev/null
+++ b/toolkit/components/places/tests/browser/browser_visituri_privatebrowsing_perwindowpb.js
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const initialURL =
+  "http://example.com/tests/toolkit/components/places/tests/browser/begin.html";
+const finalURL =
+  "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html";
+
+var observer;
+var visitSavedPromise;
+
+add_setup(async function () {
+  visitSavedPromise = new Promise(resolve => {
+    observer = {
+      observe(subject, topic, data) {
+        // The uri-visit-saved topic should only work when on normal mode.
+        if (topic == "uri-visit-saved") {
+          Services.obs.removeObserver(observer, "uri-visit-saved");
+
+          // The expected visit should be the finalURL because private mode
+          // should not register a visit with the initialURL.
+          let uri = subject.QueryInterface(Ci.nsIURI);
+          resolve(uri.spec);
+        }
+      },
+    };
+  });
+
+  Services.obs.addObserver(observer, "uri-visit-saved");
+
+  registerCleanupFunction(async function () {
+    await PlacesUtils.history.clear();
+  });
+});
+
+// Note: The private window test must be the first one to run, since we'll listen
+// to the first uri-visit-saved notification, and we expect this test to not
+// fire any, so we'll just find the non-private window test notification.
+add_task(async function test_private_browsing_window() {
+  await testLoadInWindow({ private: true }, initialURL);
+});
+
+add_task(async function test_normal_window() {
+  await testLoadInWindow({ private: false }, finalURL);
+
+  let url = await visitSavedPromise;
+  Assert.equal(url, finalURL, "Check received expected visit");
+});
+
+async function testLoadInWindow(options, url) {
+  let win = await BrowserTestUtils.openNewBrowserWindow(options);
+
+  registerCleanupFunction(async function () {
+    await BrowserTestUtils.closeWindow(win);
+  });
+
+  let loadedPromise = BrowserTestUtils.browserLoaded(
+    win.gBrowser.selectedBrowser
+  );
+  BrowserTestUtils.startLoadingURIString(win.gBrowser.selectedBrowser, url);
+  await loadedPromise;
+}
diff --git a/toolkit/components/places/tests/browser/empty_page.html b/toolkit/components/places/tests/browser/empty_page.html
new file mode 100644
index 0000000000..ac9d144cb4
--- /dev/null
+++ b/toolkit/components/places/tests/browser/empty_page.html
@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>I am an empty page</title>
+  </head>
+  <body>Empty</body>
+</html>
diff --git a/toolkit/components/places/tests/browser/favicon-normal16.png b/toolkit/components/places/tests/browser/favicon-normal16.png
new file mode 100644
index 0000000000..62b69a3d03
--- /dev/null
+++ b/toolkit/components/places/tests/browser/favicon-normal16.png
diff --git a/toolkit/components/places/tests/browser/favicon-normal32.png b/toolkit/components/places/tests/browser/favicon-normal32.png
new file mode 100644
index 0000000000..5535363c94
--- /dev/null
+++ b/toolkit/components/places/tests/browser/favicon-normal32.png
diff --git a/toolkit/components/places/tests/browser/favicon.html b/toolkit/components/places/tests/browser/favicon.html
new file mode 100644
index 0000000000..a0f5ea9594
--- /dev/null
+++ b/toolkit/components/places/tests/browser/favicon.html
@@ -0,0 +1,13 @@
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+
+<html>
+  <head>
+    <link rel="shortcut icon" href="http://example.org/tests/toolkit/components/places/tests/browser/favicon-normal32.png">
+  </head>
+  <body>
+    OK we're done!
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/final.html b/toolkit/components/places/tests/browser/final.html
new file mode 100644
index 0000000000..ccd5819181
--- /dev/null
+++ b/toolkit/components/places/tests/browser/final.html
@@ -0,0 +1,10 @@
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+
+<html>
+  <body>
+    OK we're done!
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/head.js b/toolkit/components/places/tests/browser/head.js
new file mode 100644
index 0000000000..b1b916ee29
--- /dev/null
+++ b/toolkit/components/places/tests/browser/head.js
@@ -0,0 +1,19 @@
+ChromeUtils.defineESModuleGetters(this, {
+  PlacesTestUtils: "resource://testing-common/PlacesTestUtils.sys.mjs",
+});
+
+const TRANSITION_LINK = PlacesUtils.history.TRANSITION_LINK;
+const TRANSITION_TYPED = PlacesUtils.history.TRANSITION_TYPED;
+const TRANSITION_BOOKMARK = PlacesUtils.history.TRANSITION_BOOKMARK;
+const TRANSITION_REDIRECT_PERMANENT =
+  PlacesUtils.history.TRANSITION_REDIRECT_PERMANENT;
+const TRANSITION_REDIRECT_TEMPORARY =
+  PlacesUtils.history.TRANSITION_REDIRECT_TEMPORARY;
+const TRANSITION_EMBED = PlacesUtils.history.TRANSITION_EMBED;
+const TRANSITION_FRAMED_LINK = PlacesUtils.history.TRANSITION_FRAMED_LINK;
+const TRANSITION_DOWNLOAD = PlacesUtils.history.TRANSITION_DOWNLOAD;
+
+function whenNewWindowLoaded(aOptions, aCallback) {
+  BrowserTestUtils.waitForNewWindow().then(aCallback);
+  OpenBrowserWindow(aOptions);
+}
diff --git a/toolkit/components/places/tests/browser/history_post.html b/toolkit/components/places/tests/browser/history_post.html
new file mode 100644
index 0000000000..a579a9b8ae
--- /dev/null
+++ b/toolkit/components/places/tests/browser/history_post.html
@@ -0,0 +1,12 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <title>Test post pages are not added to history</title>
+  </head>
+  <body>
+    <iframe name="post_iframe" id="post_iframe"></iframe>
+    <form method="post" action="http://example.com/tests/toolkit/components/places/tests/browser/history_post.sjs" target="post_iframe">
+      <input type="submit" id="submit"/>
+    </form>
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/history_post.sjs b/toolkit/components/places/tests/browser/history_post.sjs
new file mode 100644
index 0000000000..08c1afe853
--- /dev/null
+++ b/toolkit/components/places/tests/browser/history_post.sjs
@@ -0,0 +1,5 @@
+function handleRequest(request, response) {
+  response.setStatusLine("1.0", 200, "OK");
+  response.setHeader("Content-Type", "text/plain; charset=utf-8", false);
+  response.write("Ciao");
+}
diff --git a/toolkit/components/places/tests/browser/previews/browser.toml b/toolkit/components/places/tests/browser/previews/browser.toml
new file mode 100644
index 0000000000..10758a4803
--- /dev/null
+++ b/toolkit/components/places/tests/browser/previews/browser.toml
@@ -0,0 +1,8 @@
+[DEFAULT]
+prefs = [
+  "browser.pagethumbnails.capturing_disabled=false",
+  "places.previews.enabled=true",
+  "places.previews.log=true",
+]
+
+["browser_thumbnails.js"]
diff --git a/toolkit/components/places/tests/browser/previews/browser_thumbnails.js b/toolkit/components/places/tests/browser/previews/browser_thumbnails.js
new file mode 100644
index 0000000000..27f4fa3745
--- /dev/null
+++ b/toolkit/components/places/tests/browser/previews/browser_thumbnails.js
@@ -0,0 +1,174 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests PlacesPreviews.jsm
+ */
+const { PlacesPreviews } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesPreviews.sys.mjs"
+);
+const { PlacesTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PlacesTestUtils.sys.mjs"
+);
+
+const TEST_URL1 = "https://example.com/";
+const TEST_URL2 = "https://example.org/";
+
+/**
+ * Counts tombstone entries.
+ * @returns {integer} number of tombstone entries.
+ */
+async function countTombstones() {
+  await PlacesTestUtils.promiseAsyncUpdates();
+  let db = await PlacesUtils.promiseDBConnection();
+  return (
+    await db.execute("SELECT count(*) FROM moz_previews_tombstones")
+  )[0].getResultByIndex(0);
+}
+
+add_task(async function test_thumbnail() {
+  registerCleanupFunction(async () => {
+    await PlacesUtils.history.clear();
+    // Ensure tombstones table has been emptied.
+    await TestUtils.waitForCondition(async () => {
+      return (await countTombstones()) == 0;
+    });
+    PlacesPreviews.testSetDeletionTimeout(null);
+  });
+  // Sanity check initial state.
+  Assert.equal(await countTombstones(), 0, "There's no tombstone entries");
+
+  info("Test preview creation and storage.");
+  await BrowserTestUtils.withNewTab(TEST_URL1, async browser => {
+    await retryUpdatePreview(browser.currentURI.spec);
+    let filePath = PlacesPreviews.getPathForUrl(TEST_URL1);
+    Assert.ok(await IOUtils.exists(filePath), "The screenshot exists");
+    Assert.equal(
+      filePath.substring(filePath.lastIndexOf(".")),
+      PlacesPreviews.fileExtension,
+      "Check extension"
+    );
+    await testImageFile(filePath);
+    await testMozPageThumb(TEST_URL1);
+  });
+});
+
+add_task(async function test_page_removal() {
+  info("Store another preview and test page removal.");
+  await BrowserTestUtils.withNewTab(TEST_URL2, async browser => {
+    await retryUpdatePreview(browser.currentURI.spec);
+    let filePath = PlacesPreviews.getPathForUrl(TEST_URL2);
+    Assert.ok(await IOUtils.exists(filePath), "The screenshot exists");
+  });
+
+  // Set deletion time to a small value so it runs immediately.
+  PlacesPreviews.testSetDeletionTimeout(0);
+  info("Wait for deletion, check one preview is removed, not the other one.");
+  let promiseDeleted = new Promise(resolve => {
+    PlacesPreviews.once("places-preview-deleted", (topic, filePath) => {
+      resolve(filePath);
+    });
+  });
+  await PlacesUtils.history.remove(TEST_URL1);
+
+  let deletedFilePath = await promiseDeleted;
+  Assert.ok(
+    !(await IOUtils.exists(deletedFilePath)),
+    "Check deleted file has been removed"
+  );
+
+  info("Check tombstones table has been emptied.");
+  Assert.equal(await countTombstones(), 0, "There's no tombstone entries");
+
+  info("Check the other thumbnail has not been removed.");
+  let path = PlacesPreviews.getPathForUrl(TEST_URL2);
+  Assert.ok(await IOUtils.exists(path), "Check non-deleted url is still there");
+  await testImageFile(path);
+  await testMozPageThumb(TEST_URL2);
+});
+
+add_task(async function async_test_deleteOrphans() {
+  let path = PlacesPreviews.getPathForUrl(TEST_URL2);
+  Assert.ok(await IOUtils.exists(path), "Sanity check one preview exists");
+  // Create a file in the given path that doesn't have an entry in Places.
+  let fakePath = PathUtils.join(
+    PlacesPreviews.getPath(),
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa." + PlacesPreviews.fileExtension
+  );
+  // File contents don't matter.
+  await IOUtils.writeJSON(fakePath, { test: true });
+  let promiseDeleted = new Promise(resolve => {
+    PlacesPreviews.once("places-preview-deleted", (topic, filePath) => {
+      resolve(filePath);
+    });
+  });
+
+  await PlacesPreviews.deleteOrphans();
+  let deletedFilePath = await promiseDeleted;
+  Assert.equal(deletedFilePath, fakePath, "Check orphan has been deleted");
+  Assert.equal(await countTombstones(), 0, "There's no tombstone entries left");
+  Assert.ok(
+    !(await IOUtils.exists(fakePath)),
+    "Ensure orphan has been deleted"
+  );
+
+  Assert.ok(await IOUtils.exists(path), "Ensure valid preview is still there");
+});
+
+async function testImageFile(path) {
+  info("Load the file and check its content type.");
+  const buffer = await IOUtils.read(path);
+  const fourcc = new TextDecoder("utf-8").decode(buffer.slice(8, 12));
+  Assert.equal(fourcc, "WEBP", "Check the stored preview is webp");
+}
+
+async function testMozPageThumb(url) {
+  info("Check moz-page-thumb protocol: " + PlacesPreviews.getPageThumbURL(url));
+  let { data, contentType } = await fetchImage(
+    PlacesPreviews.getPageThumbURL(url)
+  );
+  Assert.equal(
+    contentType,
+    PlacesPreviews.fileContentType,
+    "Check the content type"
+  );
+  const fourcc = data.slice(8, 12);
+  Assert.equal(fourcc, "WEBP", "Check the returned preview is webp");
+}
+
+function fetchImage(url) {
+  return new Promise((resolve, reject) => {
+    NetUtil.asyncFetch(
+      {
+        uri: NetUtil.newURI(url),
+        loadUsingSystemPrincipal: true,
+        contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE,
+      },
+      (input, status, request) => {
+        if (!Components.isSuccessCode(status)) {
+          reject(new Error("unable to load image"));
+          return;
+        }
+
+        try {
+          let data = NetUtil.readInputStreamToString(input, input.available());
+          let contentType = request.QueryInterface(Ci.nsIChannel).contentType;
+          input.close();
+          resolve({ data, contentType });
+        } catch (ex) {
+          reject(ex);
+        }
+      }
+    );
+  });
+}
+
+/**
+ * Sometimes on macOS fetching the preview fails for timeout/network reasons,
+ * this retries so the test doesn't intermittently fail over it.
+ * @param {string} url The url to store a preview for.
+ * @returns {Promise} resolved once a preview has been captured.
+ */
+function retryUpdatePreview(url) {
+  return TestUtils.waitForCondition(() => PlacesPreviews.update(url));
+}
diff --git a/toolkit/components/places/tests/browser/redirect-target.html b/toolkit/components/places/tests/browser/redirect-target.html
new file mode 100644
index 0000000000..3700263385
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect-target.html
@@ -0,0 +1 @@
+<!DOCTYPE html><html><body><p>Ciao!</p></body></html>
diff --git a/toolkit/components/places/tests/browser/redirect.sjs b/toolkit/components/places/tests/browser/redirect.sjs
new file mode 100644
index 0000000000..ab47335ffe
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect.sjs
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function handleRequest(request, response) {
+  let page = "<!DOCTYPE html><html><body><p>Redirecting...</p></body></html>";
+
+  response.setStatusLine(request.httpVersion, "301", "Moved Permanently");
+  response.setHeader("Content-Type", "text/html", false);
+  response.setHeader("Content-Length", page.length + "", false);
+  response.setHeader("Location", "redirect-target.html", false);
+  response.write(page);
+}
diff --git a/toolkit/components/places/tests/browser/redirect_once.sjs b/toolkit/components/places/tests/browser/redirect_once.sjs
new file mode 100644
index 0000000000..b9ccd0829a
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect_once.sjs
@@ -0,0 +1,13 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+function handleRequest(request, response) {
+  response.setStatusLine("1.1", 301, "Found");
+  response.setHeader(
+    "Location",
+    "http://test1.example.com/tests/toolkit/components/places/tests/browser/final.html",
+    false
+  );
+}
diff --git a/toolkit/components/places/tests/browser/redirect_self.sjs b/toolkit/components/places/tests/browser/redirect_self.sjs
new file mode 100644
index 0000000000..953afe5f26
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect_self.sjs
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Script that redirects to itself once.
+
+function handleRequest(request, response) {
+  if (
+    request.hasHeader("Cookie") &&
+    request.getHeader("Cookie").includes("redirect-self")
+  ) {
+    response.setStatusLine("1.0", 200, "OK");
+    // Expire the cookie.
+    response.setHeader(
+      "Set-Cookie",
+      "redirect-self=true; expires=Thu, 01 Jan 1970 00:00:00 GMT",
+      true
+    );
+    response.setHeader("Content-Type", "text/plain; charset=utf-8", false);
+    response.write("OK");
+  } else {
+    response.setStatusLine(request.httpVersion, 302, "Moved Temporarily");
+    response.setHeader("Set-Cookie", "redirect-self=true", true);
+    response.setHeader("Location", "redirect_self.sjs");
+    response.write("Moved Temporarily");
+  }
+}
diff --git a/toolkit/components/places/tests/browser/redirect_thrice.sjs b/toolkit/components/places/tests/browser/redirect_thrice.sjs
new file mode 100644
index 0000000000..55154a736e
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect_thrice.sjs
@@ -0,0 +1,9 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+function handleRequest(request, response) {
+  response.setStatusLine("1.1", 302, "Found");
+  response.setHeader("Location", "redirect_twice_perma.sjs", false);
+}
diff --git a/toolkit/components/places/tests/browser/redirect_twice.sjs b/toolkit/components/places/tests/browser/redirect_twice.sjs
new file mode 100644
index 0000000000..099d20022e
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect_twice.sjs
@@ -0,0 +1,9 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+function handleRequest(request, response) {
+  response.setStatusLine("1.1", 302, "Found");
+  response.setHeader("Location", "redirect_once.sjs", false);
+}
diff --git a/toolkit/components/places/tests/browser/redirect_twice_perma.sjs b/toolkit/components/places/tests/browser/redirect_twice_perma.sjs
new file mode 100644
index 0000000000..a40abd4170
--- /dev/null
+++ b/toolkit/components/places/tests/browser/redirect_twice_perma.sjs
@@ -0,0 +1,9 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+function handleRequest(request, response) {
+  response.setStatusLine("1.1", 301, "Found");
+  response.setHeader("Location", "redirect_once.sjs", false);
+}
diff --git a/toolkit/components/places/tests/browser/title1.html b/toolkit/components/places/tests/browser/title1.html
new file mode 100644
index 0000000000..3c98d693ec
--- /dev/null
+++ b/toolkit/components/places/tests/browser/title1.html
@@ -0,0 +1,12 @@
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+
+<html>
+  <head>
+  </head>
+  <body>
+    title1.html
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/browser/title2.html b/toolkit/components/places/tests/browser/title2.html
new file mode 100644
index 0000000000..8830328796
--- /dev/null
+++ b/toolkit/components/places/tests/browser/title2.html
@@ -0,0 +1,13 @@
+<!--
+ Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/
+-->
+
+<html>
+  <head>
+    <title>Some title</title>
+  </head>
+  <body>
+    title2.html
+  </body>
+</html>
diff --git a/toolkit/components/places/tests/chrome/bad_links.atom b/toolkit/components/places/tests/chrome/bad_links.atom
new file mode 100644
index 0000000000..4469272524
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/bad_links.atom
@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+
+  <title>Example Feed</title> 
+  <link href="http://example.org/"/>
+  <updated>2003-12-13T18:30:02Z</updated>
+
+  <author> 
+    <name>John Doe</name>
+  </author> 
+  <id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>
+
+  <entry>
+
+    <title>First good item</title>
+    <link href="http://example.org/first"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
+    <updated>2003-12-13T18:30:02Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+
+  <entry>
+
+    <title>data: link</title>
+    <link href="data:text/plain,Hi"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6b</id>
+    <updated>2003-12-13T18:30:03Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+  
+  <entry>
+
+    <title>javascript: link</title>
+    <link href="javascript:alert('Hi')"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6c</id>
+    <updated>2003-12-13T18:30:04Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+  
+  <entry>
+
+    <title>file: link</title>
+    <link href="file:///var/"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6d</id>
+    <updated>2003-12-13T18:30:05Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+
+  <entry>
+
+    <title>chrome: link</title>
+    <link href="chrome://browser/content/browser.js"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6e</id>
+    <updated>2003-12-13T18:30:06Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+
+  <entry>
+
+    <title>Last good item</title>
+    <link href="http://example.org/last"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6b</id>
+    <updated>2003-12-13T18:30:07Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+
+
+</feed>
diff --git a/toolkit/components/places/tests/chrome/browser_disableglobalhistory.xhtml b/toolkit/components/places/tests/chrome/browser_disableglobalhistory.xhtml
new file mode 100644
index 0000000000..aa525e6153
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/browser_disableglobalhistory.xhtml
@@ -0,0 +1,42 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window title="Test disableglobalhistory attribute on remote browsers"
+        onload="run_test()"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <browser id="inprocess_disabled" src="about:blank" type="content" disableglobalhistory="true" />
+  <browser id="inprocess_enabled" src="about:blank" type="content" />
+
+  <browser id="remote_disabled" src="about:blank" type="content" disableglobalhistory="true" />
+  <browser id="remote_enabled" src="about:blank" type="content" />
+
+  <script type="text/javascript">
+
+  const { ContentTask } = ChromeUtils.importESModule(
+    "resource://testing-common/ContentTask.sys.mjs"
+  );
+  ContentTask.setTestScope(window.arguments[0].wrappedJSObject);
+
+  function expectUseGlobalHistory(id, expected) {
+    let browser = document.getElementById(id);
+    /* eslint-disable-next-line no-shadow */
+    return ContentTask.spawn(browser, {id, expected}, function({id, expected}) {
+      Assert.equal(docShell.browsingContext.useGlobalHistory, expected,
+                   "Got the right useGlobalHistory state in the docShell of " + id);
+    });
+  }
+
+  async function run_test() {
+    await expectUseGlobalHistory("inprocess_disabled", false);
+    await expectUseGlobalHistory("inprocess_enabled", true);
+
+    await expectUseGlobalHistory("remote_disabled", false);
+    await expectUseGlobalHistory("remote_enabled", true);
+    window.arguments[0].done();
+    ok(true);
+  }
+
+  </script>
+</window>
diff --git a/toolkit/components/places/tests/chrome/chrome.toml b/toolkit/components/places/tests/chrome/chrome.toml
new file mode 100644
index 0000000000..d83317341b
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/chrome.toml
@@ -0,0 +1,9 @@
+[DEFAULT]
+support-files = ["head.js"]
+
+["test_371798.xhtml"]
+
+["test_browser_disableglobalhistory.xhtml"]
+support-files = ["browser_disableglobalhistory.xhtml"]
+
+["test_cached_favicon.xhtml"]
diff --git a/toolkit/components/places/tests/chrome/head.js b/toolkit/components/places/tests/chrome/head.js
new file mode 100644
index 0000000000..7c03e6f33d
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/head.js
@@ -0,0 +1,8 @@
+var { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  PlacesTestUtils: "resource://testing-common/PlacesTestUtils.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+});
diff --git a/toolkit/components/places/tests/chrome/link-less-items-no-site-uri.rss b/toolkit/components/places/tests/chrome/link-less-items-no-site-uri.rss
new file mode 100644
index 0000000000..612b0a5c2e
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/link-less-items-no-site-uri.rss
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="iso-8859-1"?>
+<rss version="2.0">
+  <channel>
+    <title>feed title</title>
+    <ttl>180</ttl>
+    <item>
+      <title>linked feed item</title>
+	    <link>http://feed-item-link.com</link>
+    </item>
+    <item>
+      <title>link-less feed item</title>
+    </item>
+    <item>
+      <title>linked feed item</title>
+	    <link>http://feed-item-link.com</link>
+    </item>
+  </channel>
+</rss>
diff --git a/toolkit/components/places/tests/chrome/link-less-items.rss b/toolkit/components/places/tests/chrome/link-less-items.rss
new file mode 100644
index 0000000000..a30d4a3531
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/link-less-items.rss
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="iso-8859-1"?>
+<rss version="2.0">
+  <channel>
+    <title>feed title</title>
+    <link>http://feed-link.com</link>
+    <ttl>180</ttl>
+    <item>
+      <title>linked feed item</title>
+	    <link>http://feed-item-link.com</link>
+    </item>
+    <item>
+      <title>link-less feed item</title>
+    </item>
+    <item>
+      <title>linked feed item</title>
+	    <link>http://feed-item-link.com</link>
+    </item>
+  </channel>
+</rss>
diff --git a/toolkit/components/places/tests/chrome/rss_as_html.rss b/toolkit/components/places/tests/chrome/rss_as_html.rss
new file mode 100644
index 0000000000..e823050353
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/rss_as_html.rss
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="ISO-8859-1" ?>
+<rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/">
+<channel>
+<title>sadfasdfasdfasfasdf</title>
+<link>http://www.example.com</link>
+<description>asdfasdfasdf.example.com</description>
+<language>de</language>
+<copyright>asdfasdfasdfasdf</copyright>
+<lastBuildDate>Tue, 11 Mar 2008 18:52:52 +0100</lastBuildDate>
+<docs>http://blogs.law.harvard.edu/tech/rss</docs>
+<ttl>10</ttl>
+<item>
+<title>The First Title</title>
+<link>http://www.example.com/index.html</link>
+<pubDate>Tue, 11 Mar 2008 18:24:43 +0100</pubDate>
+<content:encoded>
+<![CDATA[
+<p>
+askdlfjas;dfkjas;fkdj
+</p>
+]]>
+</content:encoded>
+<description>aklsjdhfasdjfahasdfhj</description>
+<guid>http://foo.example.com/asdfasdf</guid>
+</item>
+</channel>
+</rss>
diff --git a/toolkit/components/places/tests/chrome/rss_as_html.rss^headers^ b/toolkit/components/places/tests/chrome/rss_as_html.rss^headers^
new file mode 100644
index 0000000000..04fbaa08fe
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/rss_as_html.rss^headers^
@@ -0,0 +1,2 @@
+HTTP 200 OK
+Content-Type: text/html
diff --git a/toolkit/components/places/tests/chrome/sample_feed.atom b/toolkit/components/places/tests/chrome/sample_feed.atom
new file mode 100644
index 0000000000..add75efb4d
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/sample_feed.atom
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+
+  <title>Example Feed</title> 
+  <link href="http://example.org/"/>
+  <updated>2003-12-13T18:30:02Z</updated>
+
+  <author> 
+    <name>John Doe</name>
+  </author> 
+  <id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id>
+
+  <entry>
+
+    <title>Atom-Powered Robots Run Amok</title>
+    <link href="http://example.org/2003/12/13/atom03"/>
+    <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
+    <updated>2003-12-13T18:30:02Z</updated>
+
+    <summary>Some text.</summary>
+  </entry>
+
+</feed>
diff --git a/toolkit/components/places/tests/chrome/test_371798.xhtml b/toolkit/components/places/tests/chrome/test_371798.xhtml
new file mode 100644
index 0000000000..33e866e51e
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/test_371798.xhtml
@@ -0,0 +1,76 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet
+  href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+<window title="Bug 371798"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script type="application/javascript" src="head.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" />
+
+<script type="application/javascript">
+<![CDATA[
+// Test the asynchronous live-updating of bookmarks query results
+SimpleTest.waitForExplicitFinish();
+
+const TEST_URI = Services.io.newURI("http://foo.com");
+
+(async function() {
+  // add 2 bookmarks to the toolbar, same URI, different titles (set later)
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: TEST_URI
+  });
+
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: TEST_URI
+  });
+
+  // query for bookmarks
+  let rootNode = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.toolbarGuid).root;
+
+  // set up observer
+  const promiseObserved = PlacesTestUtils.waitForNotification(
+    "bookmark-title-changed"
+  );
+
+  // modify the bookmark's title
+  await PlacesUtils.bookmarks.update({
+    guid: bm2.guid, title: "foo"
+  });
+
+  // wait for notification
+  await promiseObserved;
+
+  // Continue after our observer gets notified of onItemChanged
+  // which is triggered by updating the item's title.
+  // After receiving the notification, our original query should also
+  // have been live-updated, so we can iterate through its children,
+  // to check that only the modified bookmark has changed.
+
+  // result node should be updated
+  let cc = rootNode.childCount;
+  for (let i = 0; i < cc; ++i) {
+    let node = rootNode.getChild(i);
+    // test that bm1 does not have new title
+    if (node.bookmarkGuid == bm1.guid)
+      ok(node.title != "foo",
+         "Changing a bookmark's title did not affect the title of other bookmarks with the same URI");
+  }
+  rootNode.containerOpen = false;
+
+  // clean up
+  await PlacesUtils.bookmarks.remove(bm1);
+  await PlacesUtils.bookmarks.remove(bm2);
+})().catch(err => {
+  ok(false, `uncaught error: ${err}`);
+}).then(() => {
+  SimpleTest.finish();
+});
+]]>
+</script>
+
+</window>
diff --git a/toolkit/components/places/tests/chrome/test_browser_disableglobalhistory.xhtml b/toolkit/components/places/tests/chrome/test_browser_disableglobalhistory.xhtml
new file mode 100644
index 0000000000..6a7d32dabe
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/test_browser_disableglobalhistory.xhtml
@@ -0,0 +1,25 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+
+<window title="Test disableglobalhistory attribute on remote browsers"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+  <script type="text/javascript">
+  SimpleTest.waitForExplicitFinish();
+
+  let w = window.browsingContext.topChromeWindow.openDialog('browser_disableglobalhistory.xhtml', '_blank', 'chrome,resizable=yes,width=400,height=600', window);
+
+  function done() {
+    w.close();
+    SimpleTest.finish();
+  }
+  </script>
+
+</window>
diff --git a/toolkit/components/places/tests/chrome/test_cached_favicon.xhtml b/toolkit/components/places/tests/chrome/test_cached_favicon.xhtml
new file mode 100644
index 0000000000..f7e7f4f1d8
--- /dev/null
+++ b/toolkit/components/places/tests/chrome/test_cached_favicon.xhtml
@@ -0,0 +1,135 @@
+<?xml version="1.0"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/.  -->
+<!--
+ * This file tests the cached-favicon protocol, which was added in Bug 316077 and how
+ * it loads favicons.
+-->
+
+<window title="Favicon Annotation Protocol Test"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="test();">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/WindowSnapshot.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+  <script type="application/javascript" src="head.js" />
+
+  <script type="application/javascript">
+  <![CDATA[
+
+let tests = [
+  {
+    desc: "cached-favicon URI with no data in the database loads default icon",
+    url: "https://mozilla.org/2009/made-up-favicon/places-rocks/",
+    expectedIcon: PlacesUtils.favicons.defaultFavicon.spec,
+  },
+  {
+    desc: "URI added to the database is properly loaded",
+    url: "https://mozilla.org/should-be-barney/",
+    expectedIcon: "data:image/png,%89PNG%0D%0A%1A%0A%00%00%00%0DIHDR%00%00%00%10%00%00%00%10%08%06%00%00%00%1F%F3%FFa%00%00%00%04gAMA%00%00%AF%C87%05%8A%E9%00%00%00%19tEXtSoftware%00Adobe%20ImageReadyq%C9e%3C%00%00%01%D6IDATx%DAb%FC%FF%FF%3F%03%25%00%20%80%98%909%EF%DF%BFg%EF%EC%EC%FC%AD%AC%AC%FC%DF%95%91%F1%BF%89%89%C9%7F%20%FF%D7%EA%D5%AB%B7%DF%BBwO%16%9B%01%00%01%C4%00r%01%08%9F9s%C6%CD%D8%D8%F8%BF%0B%03%C3%FF3%40%BC%0A%88%EF%02q%1A%10%BB%40%F1%AAU%ABv%C1%D4%C30%40%00%81%89%993g%3E%06%1A%F6%3F%14%AA%11D%97%03%F1%7Fc%08%0D%E2%2B))%FD%17%04%89%A1%19%00%10%40%0C%D00%F8%0F3%00%C8%F8%BF%1B%E4%0Ac%88a%E5%60%17%19%FF%0F%0D%0D%05%1B%02v%D9%DD%BB%0A0%03%00%02%08%AC%B9%A3%A3%E3%17%03%D4v%90%01%EF%18%106%C3%0Cz%07%C5%BB%A1%DE%82y%07%20%80%A0%A6%08B%FCn%0C1%60%26%D4%20d%C3VA%C3%06%26%BE%0A%EA-%80%00%82%B9%E0%F7L4%0D%EF%90%F8%C6%60%2F%0A%82%BD%01%13%07%0700%D0%01%02%88%11%E4%02P%B41%DC%BB%C7%D0%014%0D%E8l%06W%20%06%BA%88%A1%1C%1AS%15%40%7C%16%CA6.%2Fgx%BFg%0F%83%CB%D9%B3%0C%7B%80%7C%80%00%02%BB%00%E8%9F%ED%20%1B%3A%A0%A6%9F%81%DA%DC%01%C5%B0%80%ED%80%FA%BF%BC%BC%FC%3F%83%12%90%9D%96%F6%1F%20%80%18%DE%BD%7B%C7%0E%8E%05AD%20%FEGr%A6%A0%A0%E0%7F%25P%80%02%9D%0F%D28%13%18%23%C6%C0%B0%02E%3D%C8%F5%00%01%04%8F%05P%A8%BA%40my%87%E4%12c%A8%8D%20%8B%D0%D3%00%08%03%04%10%9C%01R%E4%82d%3B%C8%A0%99%C6%90%90%C6%A5%19%84%01%02%08%9E%17%80%C9x%F7%7B%A0%DBVC%F9%A0%C0%5C%7D%16%2C%CE%00%F4%C6O%5C%99%09%20%800L%04y%A5%03%1A%95%A0%80%05%05%14.%DBA%18%20%80%18)%CD%CE%00%01%06%00%0C'%94%C7%C0k%C9%2C%00%00%00%00IEND%AEB%60%82",
+  },
+
+];
+
+/**
+ * The event listener placed on our test windows used to determine when it is
+ * safe to compare the two windows.
+ */
+let _results = [];
+function loadEventHandler()
+{
+  _results.push(snapshotWindow(window));
+  loadNextTest();
+}
+
+/**
+ * This runs the comparison.
+ */
+function compareResults(aIndex, aImage1, aImage2)
+{
+  let [correct, data1, data2] = compareSnapshots(aImage1, aImage2, true);
+  SimpleTest.ok(correct,
+                "Test '" + tests[aIndex].desc + "' matches expectations. " +
+                "Data from window 1 is '" + data1 + "'. " +
+                "Data from window 2 is '" + data2 + "'");
+}
+
+/**
+ * Loads the next set of URIs to compare against.
+ */
+let _counter = -1;
+function loadNextTest()
+{
+  _counter++;
+  // If we have no more tests, finish.
+  if (_counter / 2 == tests.length) {
+    for (let i = 0; i < _results.length; i = i + 2)
+      compareResults(i / 2, _results[i], _results[i + 1]);
+
+    SimpleTest.finish();
+    return;
+  }
+
+  let nextURI = function() {
+    let index = Math.floor(_counter / 2);
+    if ((_counter % 2) == 0)
+      return "cached-favicon:" + tests[index].url;
+    return tests[index].expectedIcon;
+  }
+
+  let img = document.getElementById("favicon");
+  img.setAttribute("src", nextURI());
+}
+
+function test()
+{
+  SimpleTest.waitForExplicitFinish();
+  (async () => {
+    await PlacesUtils.history.clear();
+
+    info("Inserting new visit");
+    await PlacesUtils.history.insert({
+      url: "https://example.com/favicon_annotations",
+      visits: [{
+        transition: PlacesUtils.history.TRANSITIONS.TYPED
+      }]
+    });
+
+    // Set the favicon data.  Note that the "cached-favicon:" protocol requires
+    // the favicon to be stored in the database, but the
+    // replaceFaviconDataFromDataURL function will not save the favicon
+    // unless it is associated with a page.  Thus, we must associate the
+    // icon with a page explicitly in order for it to be visible through
+    // the protocol.
+    info("Replace favicon data");
+    var systemPrincipal = Cc["@mozilla.org/systemprincipal;1"]
+                            .createInstance(Ci.nsIPrincipal);
+    PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+      Services.io.newURI(tests[1].url),
+      tests[1].expectedIcon,
+      (Date.now() + 86400) * 1000,
+      systemPrincipal);
+    info("Set favicon data");
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      Services.io.newURI("https://example.com/favicon_annotations"),
+      Services.io.newURI(tests[1].url),
+      true, PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE, null,
+      systemPrincipal);
+
+    // And start our test process.
+    loadNextTest();
+  })();
+}
+
+  ]]>
+  </script>
+
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <img id="favicon" onload="loadEventHandler();"/>
+    <p id="display"></p>
+    <div id="content" style="display:none;"></div>
+    <pre id="test"></pre>
+  </body>
+</window>
diff --git a/toolkit/components/places/tests/expiration/head_expiration.js b/toolkit/components/places/tests/expiration/head_expiration.js
new file mode 100644
index 0000000000..ce9fe48348
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/head_expiration.js
@@ -0,0 +1,112 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+/**
+ * Causes expiration component to start, otherwise it would wait for the first
+ * history notification.
+ */
+function force_expiration_start() {
+  Cc["@mozilla.org/places/expiration;1"]
+    .getService(Ci.nsIObserver)
+    .observe(null, "testing-mode", null);
+}
+
+/**
+ * Forces an expiration run.
+ *
+ * @param [optional] aLimit
+ *        Limit for the expiration.  Pass -1 for unlimited.
+ *        Any other non-positive value will just expire orphans.
+ *
+ * @return {Promise}
+ * @resolves When expiration finishes.
+ * @rejects Never.
+ */
+function promiseForceExpirationStep(aLimit) {
+  let promise = promiseTopicObserved(PlacesUtils.TOPIC_EXPIRATION_FINISHED);
+  let expire = Cc["@mozilla.org/places/expiration;1"].getService(
+    Ci.nsIObserver
+  );
+  expire.observe(null, "places-debug-start-expiration", aLimit);
+  return promise;
+}
+
+/**
+ * Expiration preferences helpers.
+ */
+
+function setInterval(aNewInterval) {
+  Services.prefs.setIntPref(
+    "places.history.expiration.interval_seconds",
+    aNewInterval
+  );
+}
+function getInterval() {
+  return Services.prefs.getIntPref(
+    "places.history.expiration.interval_seconds"
+  );
+}
+function clearInterval() {
+  try {
+    Services.prefs.clearUserPref("places.history.expiration.interval_seconds");
+  } catch (ex) {}
+}
+
+function setMaxPages(aNewMaxPages) {
+  Services.prefs.setIntPref(
+    "places.history.expiration.max_pages",
+    aNewMaxPages
+  );
+}
+function getMaxPages() {
+  return Services.prefs.getIntPref("places.history.expiration.max_pages");
+}
+function clearMaxPages() {
+  try {
+    Services.prefs.clearUserPref("places.history.expiration.max_pages");
+  } catch (ex) {}
+}
+
+function setHistoryEnabled(aHistoryEnabled) {
+  Services.prefs.setBoolPref("places.history.enabled", aHistoryEnabled);
+}
+function getHistoryEnabled() {
+  return Services.prefs.getBoolPref("places.history.enabled");
+}
+function clearHistoryEnabled() {
+  try {
+    Services.prefs.clearUserPref("places.history.enabled");
+  } catch (ex) {}
+}
+
+/**
+ * Returns a PRTime in the past usable to add expirable visits.
+ *
+ * param [optional] daysAgo
+ *       Expiration ignores any visit added in the last 7 days, so by default
+ *       this will be set to 7.
+ * @note to be safe against DST issues we go back one day more.
+ */
+function getExpirablePRTime(daysAgo = 7) {
+  let dateObj = new Date();
+  // Normalize to midnight
+  dateObj.setHours(0);
+  dateObj.setMinutes(0);
+  dateObj.setSeconds(0);
+  dateObj.setMilliseconds(0);
+  dateObj = new Date(dateObj.getTime() - (daysAgo + 1) * 86400000);
+  return dateObj.getTime() * 1000;
+}
diff --git a/toolkit/components/places/tests/expiration/test_annos_expire_never.js b/toolkit/components/places/tests/expiration/test_annos_expire_never.js
new file mode 100644
index 0000000000..39c55ecc04
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_annos_expire_never.js
@@ -0,0 +1,72 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * What this is aimed to test:
+ *
+ * EXPIRE_NEVER annotations should be expired when a page is removed from the
+ * database.
+ * If the annotation is a page annotation this will happen when the page is
+ * expired, namely when the page has no visits and is not bookmarked.
+ */
+
+add_task(async function test_annos_expire_never() {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  // Expire all expirable pages.
+  setMaxPages(0);
+
+  // Add some visited page and a couple expire never annotations for each.
+  let now = getExpirablePRTime();
+  for (let i = 0; i < 5; i++) {
+    let pageURI = uri("http://page_anno." + i + ".mozilla.org/");
+    await PlacesTestUtils.addVisits({ uri: pageURI, visitDate: now++ });
+    await PlacesUtils.history.update({
+      url: pageURI,
+      annotations: new Map([
+        ["page_expire1", "test"],
+        ["page_expire2", "test"],
+      ]),
+    });
+  }
+
+  let pages = await getPagesWithAnnotation("page_expire1");
+  Assert.equal(pages.length, 5);
+  pages = await getPagesWithAnnotation("page_expire2");
+  Assert.equal(pages.length, 5);
+
+  // Add other visited page and a couple expire never annotations for each.
+  // We won't expire these visits, so the annotations should survive.
+  for (let i = 0; i < 5; i++) {
+    let pageURI = uri("http://persist_page_anno." + i + ".mozilla.org/");
+    await PlacesTestUtils.addVisits({ uri: pageURI, visitDate: now++ });
+    await PlacesUtils.history.update({
+      url: pageURI,
+      annotations: new Map([
+        ["page_persist1", "test"],
+        ["page_persist2", "test"],
+      ]),
+    });
+  }
+
+  pages = await getPagesWithAnnotation("page_persist1");
+  Assert.equal(pages.length, 5);
+  pages = await getPagesWithAnnotation("page_persist2");
+  Assert.equal(pages.length, 5);
+
+  // Expire all visits for the first 5 pages and the bookmarks.
+  await promiseForceExpirationStep(5);
+
+  pages = await getPagesWithAnnotation("page_expire1");
+  Assert.equal(pages.length, 0);
+  pages = await getPagesWithAnnotation("page_expire2");
+  Assert.equal(pages.length, 0);
+  pages = await getPagesWithAnnotation("page_persist1");
+  Assert.equal(pages.length, 5);
+  pages = await getPagesWithAnnotation("page_persist2");
+  Assert.equal(pages.length, 5);
+});
diff --git a/toolkit/components/places/tests/expiration/test_clearHistory.js b/toolkit/components/places/tests/expiration/test_clearHistory.js
new file mode 100644
index 0000000000..a4684f0269
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_clearHistory.js
@@ -0,0 +1,57 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * What this is aimed to test:
+ *
+ * History.clear() should expire everything but bookmarked pages and valid
+ * annos.
+ */
+
+add_task(async function test_historyClear() {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  // Expire all expirable pages.
+  setMaxPages(0);
+
+  // Add some bookmarked page with visit and annotations.
+  for (let i = 0; i < 5; i++) {
+    let pageURI = uri("http://item_anno." + i + ".mozilla.org/");
+    // This visit will be expired.
+    await PlacesTestUtils.addVisits({ uri: pageURI });
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: pageURI,
+      title: null,
+    });
+    // Will persist because the page is bookmarked.
+    await PlacesUtils.history.update({
+      url: pageURI,
+      annotations: new Map([["persist", "test"]]),
+    });
+  }
+
+  // Add some visited page and annotations for each.
+  for (let i = 0; i < 5; i++) {
+    // All page annotations related to these expired pages are expected to
+    // expire as well.
+    let pageURI = uri("http://page_anno." + i + ".mozilla.org/");
+    await PlacesTestUtils.addVisits({ uri: pageURI });
+    await PlacesUtils.history.update({
+      url: pageURI,
+      annotations: new Map([["expire", "test"]]),
+    });
+  }
+
+  // Expire all visits for the bookmarks
+  await PlacesUtils.history.clear();
+
+  Assert.equal((await getPagesWithAnnotation("expire")).length, 0);
+
+  let pages = await getPagesWithAnnotation("persist");
+  Assert.equal(pages.length, 5);
+});
diff --git a/toolkit/components/places/tests/expiration/test_debug_expiration.js b/toolkit/components/places/tests/expiration/test_debug_expiration.js
new file mode 100644
index 0000000000..204295d46c
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_debug_expiration.js
@@ -0,0 +1,469 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * What this is aimed to test:
+ *
+ * Expiration can be manually triggered through a debug topic, but that should
+ * only expire orphan entries, unless -1 is passed as limit.
+ */
+
+const EXPIRE_DAYS = 90;
+var gExpirableTime = getExpirablePRTime(EXPIRE_DAYS);
+var gNonExpirableTime = getExpirablePRTime(EXPIRE_DAYS - 2);
+
+add_task(async function test_expire_orphans() {
+  // Add visits to 2 pages and force a orphan expiration. Visits should survive.
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://page1.mozilla.org/"),
+    visitDate: gExpirableTime++,
+  });
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://page2.mozilla.org/"),
+    visitDate: gExpirableTime++,
+  });
+  // Create a orphan place.
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://page3.mozilla.org/",
+    title: "",
+  });
+  await PlacesUtils.bookmarks.remove(bm);
+
+  // Expire now.
+  await promiseForceExpirationStep(0);
+
+  // Check that visits survived.
+  Assert.equal(visits_in_database("http://page1.mozilla.org/"), 1);
+  Assert.equal(visits_in_database("http://page2.mozilla.org/"), 1);
+  Assert.ok(!page_in_database("http://page3.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_orphans_optionalarg() {
+  // Add visits to 2 pages and force a orphan expiration. Visits should survive.
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://page1.mozilla.org/"),
+    visitDate: gExpirableTime++,
+  });
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://page2.mozilla.org/"),
+    visitDate: gExpirableTime++,
+  });
+  // Create a orphan place.
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://page3.mozilla.org/",
+    title: "",
+  });
+  await PlacesUtils.bookmarks.remove(bm);
+
+  // Expire now.
+  await promiseForceExpirationStep();
+
+  // Check that visits survived.
+  Assert.equal(visits_in_database("http://page1.mozilla.org/"), 1);
+  Assert.equal(visits_in_database("http://page2.mozilla.org/"), 1);
+  Assert.ok(!page_in_database("http://page3.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_limited() {
+  await PlacesTestUtils.addVisits([
+    {
+      // Should be expired cause it's the oldest visit
+      uri: "http://old.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+    {
+      // Should not be expired cause we limit 1
+      uri: "http://new.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+  ]);
+
+  // Expire now.
+  await promiseForceExpirationStep(1);
+
+  // Check that newer visit survived.
+  Assert.equal(visits_in_database("http://new.mozilla.org/"), 1);
+  // Other visits should have been expired.
+  Assert.ok(!page_in_database("http://old.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_visitcount_longurl() {
+  let longurl = "http://long.mozilla.org/" + "a".repeat(232);
+  let longurl2 = "http://long2.mozilla.org/" + "a".repeat(232);
+  await PlacesTestUtils.addVisits([
+    {
+      // Should be expired cause it's the oldest visit
+      uri: "http://old.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+    {
+      // Should not be expired cause it has 2 visits.
+      uri: longurl,
+      visitDate: gExpirableTime++,
+    },
+    {
+      uri: longurl,
+      visitDate: gNonExpirableTime,
+    },
+    {
+      // Should be expired cause it has 1 old visit.
+      uri: longurl2,
+      visitDate: gExpirableTime++,
+    },
+  ]);
+
+  await promiseForceExpirationStep(1);
+
+  // Check that some visits survived.
+  Assert.equal(visits_in_database(longurl), 2);
+  // Check visit has been removed.
+  Assert.equal(visits_in_database(longurl2), 0);
+
+  // Other visits should have been expired.
+  Assert.ok(!page_in_database("http://old.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_limited_exoticurl() {
+  await PlacesTestUtils.addVisits([
+    {
+      // Should be expired cause it's the oldest visit
+      uri: "http://old.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+    {
+      // Should not be expired cause younger than EXPIRE_DAYS.
+      uri: "http://nonexpirable-download.mozilla.org",
+      visitDate: gNonExpirableTime,
+      transition: PlacesUtils.history.TRANSITIONS.DOWNLOAD,
+    },
+    {
+      // Should be expired cause it's a long url older than EXPIRE_DAYS.
+      uri: "http://download.mozilla.org",
+      visitDate: gExpirableTime++,
+      transition: 7,
+    },
+  ]);
+
+  await promiseForceExpirationStep(1);
+
+  // Check that some visits survived.
+  Assert.equal(
+    visits_in_database("http://nonexpirable-download.mozilla.org/"),
+    1
+  );
+  // The visits are gone, the url is not yet, cause we limited the expiration
+  // to one entry, and we already removed http://old.mozilla.org/.
+  // The page normally would be expired by the next expiration run.
+  Assert.equal(visits_in_database("http://download.mozilla.org/"), 0);
+  // Other visits should have been expired.
+  Assert.ok(!page_in_database("http://old.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_exotic_hidden() {
+  let visits = [
+    {
+      // Should be expired cause it's the oldest visit
+      uri: "http://old.mozilla.org/",
+      visitDate: gExpirableTime++,
+      expectedCount: 0,
+    },
+    {
+      // Expirable typed hidden url.
+      uri: "https://typedhidden.mozilla.org/",
+      visitDate: gExpirableTime++,
+      transition: PlacesUtils.history.TRANSITIONS.FRAMED_LINK,
+      expectedCount: 2,
+    },
+    {
+      // Mark as typed.
+      uri: "https://typedhidden.mozilla.org/",
+      visitDate: gExpirableTime++,
+      transition: PlacesUtils.history.TRANSITIONS.TYPED,
+      expectedCount: 2,
+    },
+    {
+      // Expirable non-typed hidden url.
+      uri: "https://hidden.mozilla.org/",
+      visitDate: gExpirableTime++,
+      transition: PlacesUtils.history.TRANSITIONS.FRAMED_LINK,
+      expectedCount: 0,
+    },
+  ];
+  await PlacesTestUtils.addVisits(visits);
+  for (let visit of visits) {
+    Assert.greater(visits_in_database(visit.uri), 0);
+  }
+
+  await promiseForceExpirationStep(1);
+
+  for (let visit of visits) {
+    Assert.equal(
+      visits_in_database(visit.uri),
+      visit.expectedCount,
+      `${visit.uri} should${
+        visit.expectedCount == 0 ? " " : " not "
+      }have been expired`
+    );
+  }
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_unlimited() {
+  let longurl = "http://long.mozilla.org/" + "a".repeat(232);
+  await PlacesTestUtils.addVisits([
+    {
+      uri: "http://old.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+    {
+      uri: "http://new.mozilla.org/",
+      visitDate: gExpirableTime++,
+    },
+    // Add expirable visits.
+    {
+      uri: "http://download.mozilla.org/",
+      visitDate: gExpirableTime++,
+      transition: PlacesUtils.history.TRANSITION_DOWNLOAD,
+    },
+    {
+      uri: longurl,
+      visitDate: gExpirableTime++,
+    },
+
+    // Add non-expirable visits
+    {
+      uri: "http://nonexpirable.mozilla.org/",
+      visitDate: getExpirablePRTime(5),
+    },
+    {
+      uri: "http://nonexpirable-download.mozilla.org/",
+      visitDate: getExpirablePRTime(5),
+      transition: PlacesUtils.history.TRANSITION_DOWNLOAD,
+    },
+    {
+      uri: longurl,
+      visitDate: getExpirablePRTime(5),
+    },
+  ]);
+
+  await promiseForceExpirationStep(-1);
+
+  // Check that some visits survived.
+  Assert.equal(visits_in_database("http://nonexpirable.mozilla.org/"), 1);
+  Assert.equal(
+    visits_in_database("http://nonexpirable-download.mozilla.org/"),
+    1
+  );
+  Assert.equal(visits_in_database(longurl), 1);
+  // Other visits should have been expired.
+  Assert.ok(!page_in_database("http://old.mozilla.org/"));
+  Assert.ok(!page_in_database("http://download.mozilla.org/"));
+  Assert.ok(!page_in_database("http://new.mozilla.org/"));
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_expire_icons() {
+  const dataUrl =
+    "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAA" +
+    "AAAA6fptVAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJggg==";
+
+  const entries = [
+    {
+      desc: "Not expired because recent",
+      page: "https://recent.notexpired.org/",
+      icon: "https://recent.notexpired.org/test_icon.png",
+      root: "https://recent.notexpired.org/favicon.ico",
+      iconExpired: false,
+      removed: false,
+    },
+    {
+      desc: "Not expired because recent, no root",
+      page: "https://recentnoroot.notexpired.org/",
+      icon: "https://recentnoroot.notexpired.org/test_icon.png",
+      iconExpired: false,
+      removed: false,
+    },
+    {
+      desc: "Expired because old with root",
+      page: "https://oldroot.expired.org/",
+      icon: "https://oldroot.expired.org/test_icon.png",
+      root: "https://oldroot.expired.org/favicon.ico",
+      iconExpired: true,
+      removed: true,
+    },
+    {
+      desc: "Not expired because bookmarked, even if old with root",
+      page: "https://oldrootbm.notexpired.org/",
+      icon: "https://oldrootbm.notexpired.org/test_icon.png",
+      root: "https://oldrootbm.notexpired.org/favicon.ico",
+      bookmarked: true,
+      iconExpired: true,
+      removed: false,
+    },
+    {
+      desc: "Not Expired because old but has no root",
+      page: "https://old.notexpired.org/",
+      icon: "https://old.notexpired.org/test_icon.png",
+      iconExpired: true,
+      removed: false,
+    },
+    {
+      desc: "Expired because it's an orphan page",
+      page: "http://root.ref.org/#test",
+      icon: undefined,
+      iconExpired: false,
+      removed: true,
+    },
+    {
+      desc: "Expired because it's an orphan page",
+      page: "http://root.ref.org/#test",
+      icon: undefined,
+      skipHistory: true,
+      iconExpired: false,
+      removed: true,
+    },
+  ];
+
+  for (let entry of entries) {
+    if (!entry.skipHistory) {
+      await PlacesTestUtils.addVisits(entry.page);
+    }
+    if (entry.bookmarked) {
+      await PlacesUtils.bookmarks.insert({
+        url: entry.page,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      });
+    }
+
+    if (entry.icon) {
+      PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+        Services.io.newURI(entry.icon),
+        dataUrl,
+        0,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+      await PlacesTestUtils.addFavicons(new Map([[entry.page, entry.icon]]));
+      Assert.equal(
+        await getFaviconUrlForPage(entry.page),
+        entry.icon,
+        "Sanity check the icon exists"
+      );
+    } else {
+      // This is an orphan page entry.
+      await PlacesUtils.withConnectionWrapper("addOrphanPage", async db => {
+        await db.execute(
+          `INSERT INTO moz_pages_w_icons (page_url, page_url_hash)
+           VALUES (:url, hash(:url))`,
+          { url: entry.page }
+        );
+      });
+    }
+
+    if (entry.root) {
+      PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+        Services.io.newURI(entry.root),
+        dataUrl,
+        0,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+      await PlacesTestUtils.addFavicons(new Map([[entry.page, entry.root]]));
+    }
+
+    if (entry.iconExpired) {
+      // Set an expired time on the icon.
+      await PlacesUtils.withConnectionWrapper("expireFavicon", async db => {
+        await db.execute(
+          `UPDATE moz_icons_to_pages SET expire_ms = 1
+           WHERE icon_id = (SELECT id FROM moz_icons WHERE icon_url = :url)`,
+          { url: entry.icon }
+        );
+        if (entry.root) {
+          await db.execute(
+            `UPDATE moz_icons SET expire_ms = 1 WHERE icon_url = :url`,
+            { url: entry.root }
+          );
+        }
+      });
+    }
+    if (entry.icon) {
+      Assert.equal(
+        await getFaviconUrlForPage(entry.page),
+        entry.icon,
+        "Sanity check the initial icon value"
+      );
+    }
+  }
+
+  info("Run expiration");
+  await promiseForceExpirationStep(-1);
+
+  info("Check expiration");
+  for (let entry of entries) {
+    Assert.ok(page_in_database(entry.page));
+
+    if (!entry.removed) {
+      Assert.equal(
+        await getFaviconUrlForPage(entry.page),
+        entry.icon,
+        entry.desc
+      );
+      continue;
+    }
+
+    if (entry.root) {
+      Assert.equal(
+        await getFaviconUrlForPage(entry.page),
+        entry.root,
+        entry.desc
+      );
+      continue;
+    }
+
+    if (entry.icon) {
+      await Assert.rejects(
+        getFaviconUrlForPage(entry.page),
+        /Unable to find an icon/,
+        entry.desc
+      );
+      continue;
+    }
+
+    // This was an orphan page entry.
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(
+      `SELECT count(*) FROM moz_pages_w_icons WHERE page_url_hash = hash(:url)`,
+      { url: entry.page }
+    );
+    Assert.equal(rows[0].getResultByIndex(0), 0, "Orphan page was removed");
+  }
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+add_setup(async function () {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+  // Set maxPages to a low value, so it's easy to go over it.
+  setMaxPages(1);
+});
diff --git a/toolkit/components/places/tests/expiration/test_idle_daily.js b/toolkit/components/places/tests/expiration/test_idle_daily.js
new file mode 100644
index 0000000000..11547e37dc
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_idle_daily.js
@@ -0,0 +1,22 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test that expiration runs on idle-daily.
+
+add_task(async function test_expiration_on_idle_daily() {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  let expirationPromise = TestUtils.topicObserved(
+    PlacesUtils.TOPIC_EXPIRATION_FINISHED
+  );
+
+  let expire = Cc["@mozilla.org/places/expiration;1"].getService(
+    Ci.nsIObserver
+  );
+  expire.observe(null, "idle-daily", null);
+
+  await expirationPromise;
+});
diff --git a/toolkit/components/places/tests/expiration/test_interactions_expiration.js b/toolkit/components/places/tests/expiration/test_interactions_expiration.js
new file mode 100644
index 0000000000..67b4b466c3
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_interactions_expiration.js
@@ -0,0 +1,102 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests expiration of Places interactions data.
+ */
+// Number of days in the past where interactions will be expired.
+const EXPIRE_DAYS = 60;
+// Should be more recent than EXPIRED_DAYS.
+const RECENT_DATE = new Date() - (EXPIRE_DAYS - 1) * 86400000;
+
+add_task(async function setup() {
+  Services.prefs.setBoolPref("browser.places.interactions.enabled", true);
+  Services.prefs.setIntPref(
+    "browser.places.interactions.expireDays",
+    EXPIRE_DAYS
+  );
+});
+
+add_task(async function test_expire_interactions() {
+  // Add visits and metadata to 2 pages and force expiration.
+  await PlacesTestUtils.addVisits([
+    "https://expired.mozilla.org/",
+    "https://interactions-expired.mozilla.org/",
+    "https://some-interaction-expired.mozilla.org/",
+    "https://not-expired.mozilla.org/",
+  ]);
+  // Insert dummy interactions for all the pages.
+  await addDummyInteractions("https://removed.mozilla.org/", [0]);
+  await addDummyInteractions("https://interactions-expired.mozilla.org/", [
+    EXPIRE_DAYS + 10,
+  ]);
+  await addDummyInteractions("https://some-interactions-expired.mozilla.org/", [
+    0,
+    EXPIRE_DAYS + 10,
+  ]);
+  await addDummyInteractions("https://not-expired.mozilla.org/", [
+    0,
+    EXPIRE_DAYS / 2,
+  ]);
+
+  info("Remove a page from history and check interactions are removed");
+  await PlacesUtils.history.remove("https://removed.mozilla.org/");
+  await checkDummyInteractions("https://removed.mozilla.org/", 0);
+
+  // Expire now.
+  await promiseForceExpirationStep(-1);
+
+  info("Test interactions expiration result");
+  await checkDummyInteractions("https://interactions-expired.mozilla.org/", 0);
+  await checkDummyInteractions(
+    "https://some-interactions-expired.mozilla.org/",
+    1
+  );
+  await checkDummyInteractions("https://not-expired.mozilla.org/", 2);
+
+  // Clean up.
+  await PlacesUtils.history.clear();
+});
+
+async function addDummyInteractions(url, interactionDaysAgo) {
+  await PlacesTestUtils.addVisits(url);
+  await PlacesUtils.withConnectionWrapper(
+    "test_interactions_expiration.js: addDummyInteraction",
+    async db => {
+      await db.execute(
+        `INSERT INTO moz_places_metadata (place_id, created_at, updated_at) VALUES (
+        (SELECT id FROM moz_places WHERE url_hash = hash(:url)),
+        strftime('%s','now','localtime','-' || :days || ' day','start of day','utc') * 1000,
+        strftime('%s','now','localtime','-' || :days || ' day','start of day','utc') * 1000
+      )`,
+        interactionDaysAgo.map(days => ({ url, days }))
+      );
+    }
+  );
+}
+
+async function checkDummyInteractions(url, interactionsLen) {
+  info("Check interactions for " + url);
+  await PlacesUtils.withConnectionWrapper(
+    "test_interactions_expiration.js: addDummyInteraction",
+    async db => {
+      let rows = await db.execute(
+        `SELECT updated_at
+         FROM moz_places_metadata
+         WHERE place_id = (SELECT id FROM moz_places WHERE url_hash = hash(:url))
+         ORDER BY updated_at DESC`,
+        { url }
+      );
+      let dates = rows.map(r => new Date(r.getResultByName("updated_at")));
+      Assert.equal(
+        rows.length,
+        interactionsLen,
+        "Found expected number of interactions"
+      );
+      Assert.ok(
+        dates.every(d => d > RECENT_DATE),
+        "All interactions are recent"
+      );
+    }
+  );
+}
diff --git a/toolkit/components/places/tests/expiration/test_notifications.js b/toolkit/components/places/tests/expiration/test_notifications.js
new file mode 100644
index 0000000000..d52319a9c9
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_notifications.js
@@ -0,0 +1,36 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/**
+ * What this is aimed to test:
+ *
+ * Ensure that History (through category cache) notifies us just once.
+ */
+
+var gObserver = {
+  notifications: 0,
+  observe(aSubject, aTopic, aData) {
+    this.notifications++;
+  },
+};
+Services.obs.addObserver(gObserver, PlacesUtils.TOPIC_EXPIRATION_FINISHED);
+
+add_task(async function test_history_expirations_notify_just_once() {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  promiseForceExpirationStep(1);
+
+  await new Promise(resolve => {
+    do_timeout(2000, resolve);
+  });
+
+  Assert.equal(gObserver.notifications, 1);
+
+  Services.obs.removeObserver(gObserver, PlacesUtils.TOPIC_EXPIRATION_FINISHED);
+});
diff --git a/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_allVisits.js b/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_allVisits.js
new file mode 100644
index 0000000000..172f29cf96
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_allVisits.js
@@ -0,0 +1,156 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * What this is aimed to test:
+ *
+ * Expiring only visits for a page, but not the full page, should fire an
+ * page-removed for all visits notification.
+ */
+
+var tests = [
+  {
+    desc: "Add 1 bookmarked page.",
+    addPages: 1,
+    visitsPerPage: 1,
+    addBookmarks: 1,
+    limitExpiration: -1,
+    expectedNotifications: 1, // Will expire visits for 1 page.
+    expectedIsPartialRemoval: true,
+  },
+
+  {
+    desc: "Add 2 pages, 1 bookmarked.",
+    addPages: 2,
+    visitsPerPage: 1,
+    addBookmarks: 1,
+    limitExpiration: -1,
+    expectedNotifications: 1, // Will expire visits for 1 page.
+    expectedIsPartialRemoval: true,
+  },
+
+  {
+    desc: "Add 10 pages, none bookmarked.",
+    addPages: 10,
+    visitsPerPage: 1,
+    addBookmarks: 0,
+    limitExpiration: -1,
+    expectedNotifications: 0, // Will expire only full pages.
+    expectedIsPartialRemoval: false,
+  },
+
+  {
+    desc: "Add 10 pages, all bookmarked.",
+    addPages: 10,
+    visitsPerPage: 1,
+    addBookmarks: 10,
+    limitExpiration: -1,
+    expectedNotifications: 10, // Will expire visits for all pages.
+    expectedIsPartialRemoval: true,
+  },
+
+  {
+    desc: "Add 10 pages with lot of visits, none bookmarked.",
+    addPages: 10,
+    visitsPerPage: 10,
+    addBookmarks: 0,
+    limitExpiration: 10,
+    expectedNotifications: 10, // Will expire 1 visit for each page, but won't
+    // expire pages since they still have visits.
+    expectedIsPartialRemoval: true,
+  },
+];
+
+add_task(async () => {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  // Expire anything that is expirable.
+  setMaxPages(0);
+
+  for (let testIndex = 1; testIndex <= tests.length; testIndex++) {
+    let currentTest = tests[testIndex - 1];
+    info("TEST " + testIndex + ": " + currentTest.desc);
+    currentTest.receivedNotifications = 0;
+
+    // Setup visits.
+    let timeInMicroseconds = getExpirablePRTime(8);
+
+    function newTimeInMicroseconds() {
+      timeInMicroseconds = timeInMicroseconds + 1000;
+      return timeInMicroseconds;
+    }
+
+    for (let j = 0; j < currentTest.visitsPerPage; j++) {
+      for (let i = 0; i < currentTest.addPages; i++) {
+        let page = "http://" + testIndex + "." + i + ".mozilla.org/";
+        await PlacesTestUtils.addVisits({
+          uri: uri(page),
+          visitDate: newTimeInMicroseconds(),
+        });
+      }
+    }
+
+    // Setup bookmarks.
+    currentTest.bookmarks = [];
+    for (let i = 0; i < currentTest.addBookmarks; i++) {
+      let page = "http://" + testIndex + "." + i + ".mozilla.org/";
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: null,
+        url: page,
+      });
+      currentTest.bookmarks.push(page);
+    }
+
+    // Observe history.
+    let notificationsHandled = new Promise(resolve => {
+      const listener = async events => {
+        for (const event of events) {
+          Assert.equal(event.type, "page-removed");
+          Assert.equal(event.reason, PlacesVisitRemoved.REASON_EXPIRED);
+
+          if (event.isRemovedFromStore) {
+            // Check this uri was not bookmarked.
+            Assert.equal(currentTest.bookmarks.indexOf(event.url), -1);
+            do_check_valid_places_guid(event.pageGuid);
+          } else {
+            currentTest.receivedNotifications++;
+            await check_guid_for_uri(
+              Services.io.newURI(event.url),
+              event.pageGuid
+            );
+            Assert.equal(
+              event.isPartialVisistsRemoval,
+              currentTest.expectedIsPartialRemoval,
+              "Should have the correct flag setting for partial removal"
+            );
+          }
+        }
+        PlacesObservers.removeListener(["page-removed"], listener);
+        resolve();
+      };
+      PlacesObservers.addListener(["page-removed"], listener);
+    });
+
+    // Expire now.
+    await promiseForceExpirationStep(currentTest.limitExpiration);
+    await notificationsHandled;
+
+    Assert.equal(
+      currentTest.receivedNotifications,
+      currentTest.expectedNotifications
+    );
+
+    // Clean up.
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  }
+
+  clearMaxPages();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_fromStore.js b/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_fromStore.js
new file mode 100644
index 0000000000..c8f7cf4aa0
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_notifications_pageRemoved_fromStore.js
@@ -0,0 +1,110 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * What this is aimed to test:
+ *
+ * Expiring a full page should fire an page-removed event notification.
+ */
+
+var tests = [
+  {
+    desc: "Add 1 bookmarked page.",
+    addPages: 1,
+    addBookmarks: 1,
+    expectedNotifications: 0, // No expirable pages.
+  },
+
+  {
+    desc: "Add 2 pages, 1 bookmarked.",
+    addPages: 2,
+    addBookmarks: 1,
+    expectedNotifications: 1, // Only one expirable page.
+  },
+
+  {
+    desc: "Add 10 pages, none bookmarked.",
+    addPages: 10,
+    addBookmarks: 0,
+    expectedNotifications: 10, // Will expire everything.
+  },
+
+  {
+    desc: "Add 10 pages, all bookmarked.",
+    addPages: 10,
+    addBookmarks: 10,
+    expectedNotifications: 0, // No expirable pages.
+  },
+];
+
+add_task(async () => {
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  // Expire anything that is expirable.
+  setMaxPages(0);
+
+  for (let testIndex = 1; testIndex <= tests.length; testIndex++) {
+    let currentTest = tests[testIndex - 1];
+    print("\nTEST " + testIndex + ": " + currentTest.desc);
+    currentTest.receivedNotifications = 0;
+
+    // Setup visits.
+    let now = getExpirablePRTime();
+    for (let i = 0; i < currentTest.addPages; i++) {
+      let page = "http://" + testIndex + "." + i + ".mozilla.org/";
+      await PlacesTestUtils.addVisits({ uri: uri(page), visitDate: now++ });
+    }
+
+    // Setup bookmarks.
+    currentTest.bookmarks = [];
+    for (let i = 0; i < currentTest.addBookmarks; i++) {
+      let page = "http://" + testIndex + "." + i + ".mozilla.org/";
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: null,
+        url: page,
+      });
+      currentTest.bookmarks.push(page);
+    }
+
+    // Observe history.
+    const listener = events => {
+      for (const event of events) {
+        Assert.equal(event.type, "page-removed");
+
+        if (!event.isRemovedFromStore) {
+          continue;
+        }
+
+        currentTest.receivedNotifications++;
+        // Check this uri was not bookmarked.
+        Assert.equal(currentTest.bookmarks.indexOf(event.url), -1);
+        do_check_valid_places_guid(event.pageGuid);
+        Assert.equal(event.reason, PlacesVisitRemoved.REASON_EXPIRED);
+      }
+    };
+    PlacesObservers.addListener(["page-removed"], listener);
+
+    // Expire now.
+    await promiseForceExpirationStep(-1);
+
+    PlacesObservers.removeListener(["page-removed"], listener);
+
+    Assert.equal(
+      currentTest.receivedNotifications,
+      currentTest.expectedNotifications
+    );
+
+    // Clean up.
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  }
+
+  clearMaxPages();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/expiration/test_pref_interval.js b/toolkit/components/places/tests/expiration/test_pref_interval.js
new file mode 100644
index 0000000000..5bf340e7c4
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_pref_interval.js
@@ -0,0 +1,62 @@
+/**
+ * What this is aimed to test:
+ *
+ * Expiration relies on an interval, that is user-preffable setting
+ * "places.history.expiration.interval_seconds".
+ * On pref change it will stop current interval timer and fire a new one,
+ * that will obey the new value.
+ * If the pref is set to a number <= 0 we will use the default value.
+ */
+
+// Default timer value for expiration in seconds.  Must have same value as
+// PREF_INTERVAL_SECONDS_NOTSET in nsPlacesExpiration.
+const DEFAULT_TIMER_DELAY_SECONDS = 3 * 60;
+
+// Sync this with the const value in the component.
+const EXPIRE_AGGRESSIVITY_MULTIPLIER = 3;
+
+var tests = [
+  {
+    desc: "Set interval to 1s.",
+    interval: 1,
+    expectedTimerDelay: 1 * EXPIRE_AGGRESSIVITY_MULTIPLIER,
+  },
+
+  {
+    desc: "Set interval to a negative value.",
+    interval: -1,
+    expectedTimerDelay:
+      DEFAULT_TIMER_DELAY_SECONDS * EXPIRE_AGGRESSIVITY_MULTIPLIER,
+  },
+
+  {
+    desc: "Set interval to 0.",
+    interval: 0,
+    expectedTimerDelay:
+      DEFAULT_TIMER_DELAY_SECONDS * EXPIRE_AGGRESSIVITY_MULTIPLIER,
+  },
+
+  {
+    desc: "Set interval to a large value.",
+    interval: 100,
+    expectedTimerDelay: 100 * EXPIRE_AGGRESSIVITY_MULTIPLIER,
+  },
+];
+
+add_task(async function test() {
+  // The pref should not exist by default.
+  Assert.throws(() => getInterval(), /NS_ERROR_UNEXPECTED/);
+
+  // Force the component, so it will start observing preferences.
+  force_expiration_start();
+
+  for (let currentTest of tests) {
+    currentTest = tests.shift();
+    print(currentTest.desc);
+    let promise = promiseTopicObserved("test-interval-changed");
+    setInterval(currentTest.interval);
+    let [, data] = await promise;
+    Assert.equal(data, currentTest.expectedTimerDelay);
+  }
+  clearInterval();
+});
diff --git a/toolkit/components/places/tests/expiration/test_pref_maxpages.js b/toolkit/components/places/tests/expiration/test_pref_maxpages.js
new file mode 100644
index 0000000000..e4583359f1
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/test_pref_maxpages.js
@@ -0,0 +1,116 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * What this is aimed to test:
+ *
+ * Expiration will obey to hardware spec, but user can set a custom maximum
+ * number of pages to retain, to restrict history, through
+ * "places.history.expiration.max_pages".
+ * This limit is used at next expiration run.
+ * If the pref is set to a number < 0 we will use the default value.
+ */
+
+var tests = [
+  {
+    desc: "Set max_pages to a negative value, with 1 page.",
+    maxPages: -1,
+    addPages: 1,
+    expectedNotifications: 0, // Will ignore and won't expire anything.
+  },
+
+  {
+    desc: "Set max_pages to 0.",
+    maxPages: 0,
+    addPages: 1,
+    expectedNotifications: 1,
+  },
+
+  {
+    desc: "Set max_pages to 0, with 2 pages.",
+    maxPages: 0,
+    addPages: 2,
+    expectedNotifications: 2, // Will expire everything.
+  },
+
+  // Notice if we are over limit we do a full step of expiration.  So we ensure
+  // that we will expire if we are over the limit, but we don't ensure that we
+  // will expire exactly up to the limit.  Thus in this case we expire
+  // everything.
+  {
+    desc: "Set max_pages to 1 with 2 pages.",
+    maxPages: 1,
+    addPages: 2,
+    expectedNotifications: 2, // Will expire everything (in this case).
+  },
+
+  {
+    desc: "Set max_pages to 10, with 9 pages.",
+    maxPages: 10,
+    addPages: 9,
+    expectedNotifications: 0, // We are at the limit, won't expire anything.
+  },
+
+  {
+    desc: "Set max_pages to 10 with 10 pages.",
+    maxPages: 10,
+    addPages: 10,
+    expectedNotifications: 0, // We are below the limit, won't expire anything.
+  },
+];
+
+add_task(async function test_pref_maxpages() {
+  // The pref should not exist by default.
+  try {
+    getMaxPages();
+    do_throw("interval pref should not exist by default");
+  } catch (ex) {}
+
+  // Set interval to a large value so we don't expire on it.
+  setInterval(3600); // 1h
+
+  for (let testIndex = 1; testIndex <= tests.length; testIndex++) {
+    let currentTest = tests[testIndex - 1];
+    print("\nTEST " + testIndex + ": " + currentTest.desc);
+    currentTest.receivedNotifications = 0;
+
+    // Setup visits.
+    let now = getExpirablePRTime();
+    for (let i = 0; i < currentTest.addPages; i++) {
+      let page = "http://" + testIndex + "." + i + ".mozilla.org/";
+      await PlacesTestUtils.addVisits({ uri: uri(page), visitDate: now-- });
+    }
+
+    const listener = events => {
+      for (const event of events) {
+        print("page-removed " + event.url);
+        Assert.equal(event.type, "page-removed");
+        Assert.ok(event.isRemovedFromStore);
+        Assert.equal(event.reason, PlacesVisitRemoved.REASON_EXPIRED);
+        currentTest.receivedNotifications++;
+      }
+    };
+    PlacesObservers.addListener(["page-removed"], listener);
+
+    setMaxPages(currentTest.maxPages);
+
+    // Expire now.
+    await promiseForceExpirationStep(-1);
+
+    PlacesObservers.removeListener(["page-removed"], listener);
+
+    Assert.equal(
+      currentTest.receivedNotifications,
+      currentTest.expectedNotifications
+    );
+
+    // Clean up.
+    await PlacesUtils.history.clear();
+  }
+
+  clearMaxPages();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/expiration/xpcshell.toml b/toolkit/components/places/tests/expiration/xpcshell.toml
new file mode 100644
index 0000000000..dc9dc7e619
--- /dev/null
+++ b/toolkit/components/places/tests/expiration/xpcshell.toml
@@ -0,0 +1,23 @@
+[DEFAULT]
+head = "head_expiration.js"
+skip-if = ["os == 'android'"]
+
+["test_annos_expire_never.js"]
+
+["test_clearHistory.js"]
+
+["test_debug_expiration.js"]
+
+["test_idle_daily.js"]
+
+["test_interactions_expiration.js"]
+
+["test_notifications.js"]
+
+["test_notifications_pageRemoved_allVisits.js"]
+
+["test_notifications_pageRemoved_fromStore.js"]
+
+["test_pref_interval.js"]
+
+["test_pref_maxpages.js"]
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-animated16.png.png b/toolkit/components/places/tests/favicons/expected-favicon-animated16.png.png
new file mode 100644
index 0000000000..22f825c500
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-animated16.png.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-big16.ico.png b/toolkit/components/places/tests/favicons/expected-favicon-big16.ico.png
new file mode 100644
index 0000000000..fa61cc5046
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-big16.ico.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-big32.jpg.png b/toolkit/components/places/tests/favicons/expected-favicon-big32.jpg.png
new file mode 100644
index 0000000000..42640cbb53
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-big32.jpg.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-big4.jpg.png b/toolkit/components/places/tests/favicons/expected-favicon-big4.jpg.png
new file mode 100644
index 0000000000..81d1b8ae19
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-big4.jpg.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-big48.ico.png b/toolkit/components/places/tests/favicons/expected-favicon-big48.ico.png
new file mode 100644
index 0000000000..7983889098
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-big48.ico.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-big64.png.png b/toolkit/components/places/tests/favicons/expected-favicon-big64.png.png
new file mode 100644
index 0000000000..2756cf0cb3
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-big64.png.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-scale160x3.jpg.png b/toolkit/components/places/tests/favicons/expected-favicon-scale160x3.jpg.png
new file mode 100644
index 0000000000..fc464f8e99
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-scale160x3.jpg.png
diff --git a/toolkit/components/places/tests/favicons/expected-favicon-scale3x160.jpg.png b/toolkit/components/places/tests/favicons/expected-favicon-scale3x160.jpg.png
new file mode 100644
index 0000000000..c1412038a3
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/expected-favicon-scale3x160.jpg.png
diff --git a/toolkit/components/places/tests/favicons/favicon-animated16.png b/toolkit/components/places/tests/favicons/favicon-animated16.png
new file mode 100644
index 0000000000..8913387fc9
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-animated16.png
diff --git a/toolkit/components/places/tests/favicons/favicon-big16.ico b/toolkit/components/places/tests/favicons/favicon-big16.ico
new file mode 100644
index 0000000000..d44438903b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-big16.ico
diff --git a/toolkit/components/places/tests/favicons/favicon-big32.jpg b/toolkit/components/places/tests/favicons/favicon-big32.jpg
new file mode 100644
index 0000000000..b2131bf0c1
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-big32.jpg
diff --git a/toolkit/components/places/tests/favicons/favicon-big4.jpg b/toolkit/components/places/tests/favicons/favicon-big4.jpg
new file mode 100644
index 0000000000..b84fcd35a6
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-big4.jpg
diff --git a/toolkit/components/places/tests/favicons/favicon-big48.ico b/toolkit/components/places/tests/favicons/favicon-big48.ico
new file mode 100644
index 0000000000..f22522411d
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-big48.ico
diff --git a/toolkit/components/places/tests/favicons/favicon-big64.png b/toolkit/components/places/tests/favicons/favicon-big64.png
new file mode 100644
index 0000000000..2756cf0cb3
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-big64.png
diff --git a/toolkit/components/places/tests/favicons/favicon-multi-frame16.png b/toolkit/components/places/tests/favicons/favicon-multi-frame16.png
new file mode 100644
index 0000000000..519e08cc21
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-multi-frame16.png
diff --git a/toolkit/components/places/tests/favicons/favicon-multi-frame32.png b/toolkit/components/places/tests/favicons/favicon-multi-frame32.png
new file mode 100644
index 0000000000..5ae61de789
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-multi-frame32.png
diff --git a/toolkit/components/places/tests/favicons/favicon-multi-frame64.png b/toolkit/components/places/tests/favicons/favicon-multi-frame64.png
new file mode 100644
index 0000000000..57123f351b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-multi-frame64.png
diff --git a/toolkit/components/places/tests/favicons/favicon-multi.ico b/toolkit/components/places/tests/favicons/favicon-multi.ico
new file mode 100644
index 0000000000..e98adcafeb
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-multi.ico
diff --git a/toolkit/components/places/tests/favicons/favicon-normal16.png b/toolkit/components/places/tests/favicons/favicon-normal16.png
new file mode 100644
index 0000000000..62b69a3d03
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-normal16.png
diff --git a/toolkit/components/places/tests/favicons/favicon-normal32.png b/toolkit/components/places/tests/favicons/favicon-normal32.png
new file mode 100644
index 0000000000..5535363c94
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-normal32.png
diff --git a/toolkit/components/places/tests/favicons/favicon-scale160x3.jpg b/toolkit/components/places/tests/favicons/favicon-scale160x3.jpg
new file mode 100644
index 0000000000..422ee7ea0b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-scale160x3.jpg
diff --git a/toolkit/components/places/tests/favicons/favicon-scale3x160.jpg b/toolkit/components/places/tests/favicons/favicon-scale3x160.jpg
new file mode 100644
index 0000000000..e8514966a0
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/favicon-scale3x160.jpg
diff --git a/toolkit/components/places/tests/favicons/head_favicons.js b/toolkit/components/places/tests/favicons/head_favicons.js
new file mode 100644
index 0000000000..d8109c66e0
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/head_favicons.js
@@ -0,0 +1,81 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+const systemPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
+
+/**
+ * Checks that the favicon for the given page matches the provided data.
+ *
+ * @param aPageURI
+ *        nsIURI object for the page to check.
+ * @param aExpectedMimeType
+ *        Expected MIME type of the icon, for example "image/png".
+ * @param aExpectedData
+ *        Expected icon data, expressed as an array of byte values.
+ * @param aCallback
+ *        This function is called after the check finished.
+ */
+function checkFaviconDataForPage(
+  aPageURI,
+  aExpectedMimeType,
+  aExpectedData,
+  aCallback
+) {
+  PlacesUtils.favicons.getFaviconDataForPage(
+    aPageURI,
+    async function (aURI, aDataLen, aData, aMimeType) {
+      Assert.equal(aExpectedMimeType, aMimeType);
+      Assert.ok(compareArrays(aExpectedData, aData));
+      await check_guid_for_uri(aPageURI);
+      aCallback();
+    }
+  );
+}
+
+/**
+ * Checks that the given page has no associated favicon.
+ *
+ * @param aPageURI
+ *        nsIURI object for the page to check.
+ * @param aCallback
+ *        This function is called after the check finished.
+ */
+function checkFaviconMissingForPage(aPageURI, aCallback) {
+  PlacesUtils.favicons.getFaviconURLForPage(
+    aPageURI,
+    function (aURI, aDataLen, aData, aMimeType) {
+      Assert.ok(aURI === null);
+      aCallback();
+    }
+  );
+}
+
+function promiseFaviconMissingForPage(aPageURI) {
+  return new Promise(resolve => checkFaviconMissingForPage(aPageURI, resolve));
+}
+
+function promiseFaviconChanged(aExpectedPageURI, aExpectedFaviconURI) {
+  return new Promise(resolve => {
+    PlacesTestUtils.waitForNotification("favicon-changed", async events => {
+      for (let e of events) {
+        if (e.url == aExpectedPageURI.spec) {
+          Assert.equal(e.faviconUrl, aExpectedFaviconURI.spec);
+          await check_guid_for_uri(aExpectedPageURI, e.pageGuid);
+          resolve();
+        }
+      }
+    });
+  });
+}
diff --git a/toolkit/components/places/tests/favicons/noise.png b/toolkit/components/places/tests/favicons/noise.png
new file mode 100644
index 0000000000..d6876295cd
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/noise.png
diff --git a/toolkit/components/places/tests/favicons/test_cached-favicon_mime_type.js b/toolkit/components/places/tests/favicons/test_cached-favicon_mime_type.js
new file mode 100644
index 0000000000..1c95d63f94
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_cached-favicon_mime_type.js
@@ -0,0 +1,88 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This test ensures that the mime type is set for cached-favicon channels of favicons
+ * properly.  Added with work in bug 481227.
+ */
+
+const testFaviconData =
+  "data:image/png,%89PNG%0D%0A%1A%0A%00%00%00%0DIHDR%00%00%00%10%00%00%00%10%08%06%00%00%00%1F%F3%FFa%00%00%00%04gAMA%00%00%AF%C87%05%8A%E9%00%00%00%19tEXtSoftware%00Adobe%20ImageReadyq%C9e%3C%00%00%01%D6IDATx%DAb%FC%FF%FF%3F%03%25%00%20%80%98%909%EF%DF%BFg%EF%EC%EC%FC%AD%AC%AC%FC%DF%95%91%F1%BF%89%89%C9%7F%20%FF%D7%EA%D5%AB%B7%DF%BBwO%16%9B%01%00%01%C4%00r%01%08%9F9s%C6%CD%D8%D8%F8%BF%0B%03%C3%FF3%40%BC%0A%88%EF%02q%1A%10%BB%40%F1%AAU%ABv%C1%D4%C30%40%00%81%89%993g%3E%06%1A%F6%3F%14%AA%11D%97%03%F1%7Fc%08%0D%E2%2B))%FD%17%04%89%A1%19%00%10%40%0C%D00%F8%0F3%00%C8%F8%BF%1B%E4%0Ac%88a%E5%60%17%19%FF%0F%0D%0D%05%1B%02v%D9%DD%BB%0A0%03%00%02%08%AC%B9%A3%A3%E3%17%03%D4v%90%01%EF%18%106%C3%0Cz%07%C5%BB%A1%DE%82y%07%20%80%A0%A6%08B%FCn%0C1%60%26%D4%20d%C3VA%C3%06%26%BE%0A%EA-%80%00%82%B9%E0%F7L4%0D%EF%90%F8%C6%60%2F%0A%82%BD%01%13%07%0700%D0%01%02%88%11%E4%02P%B41%DC%BB%C7%D0%014%0D%E8l%06W%20%06%BA%88%A1%1C%1AS%15%40%7C%16%CA6.%2Fgx%BFg%0F%83%CB%D9%B3%0C%7B%80%7C%80%00%02%BB%00%E8%9F%ED%20%1B%3A%A0%A6%9F%81%DA%DC%01%C5%B0%80%ED%80%FA%BF%BC%BC%FC%3F%83%12%90%9D%96%F6%1F%20%80%18%DE%BD%7B%C7%0E%8E%05AD%20%FEGr%A6%A0%A0%E0%7F%25P%80%02%9D%0F%D28%13%18%23%C6%C0%B0%02E%3D%C8%F5%00%01%04%8F%05P%A8%BA%40my%87%E4%12c%A8%8D%20%8B%D0%D3%00%08%03%04%10%9C%01R%E4%82d%3B%C8%A0%99%C6%90%90%C6%A5%19%84%01%02%08%9E%17%80%C9x%F7%7B%A0%DBVC%F9%A0%C0%5C%7D%16%2C%CE%00%F4%C6O%5C%99%09%20%800L%04y%A5%03%1A%95%A0%80%05%05%14.%DBA%18%20%80%18)%CD%CE%00%01%06%00%0C'%94%C7%C0k%C9%2C%00%00%00%00IEND%AEB%60%82";
+const testIconURI = uri("http://mozilla.org/favicon.png");
+
+function streamListener(aExpectedContentType) {
+  this._expectedContentType = aExpectedContentType;
+  this.done = Promise.withResolvers();
+}
+streamListener.prototype = {
+  onStartRequest() {},
+  onStopRequest(aRequest, aContext, aStatusCode) {
+    let channel = aRequest.QueryInterface(Ci.nsIChannel);
+    Assert.equal(
+      channel.contentType,
+      this._expectedContentType,
+      "The channel content type is the expected one"
+    );
+    this.done.resolve();
+  },
+  onDataAvailable(aRequest, aInputStream, aOffset, aCount) {
+    aRequest.cancel(Cr.NS_ERROR_ABORT);
+    throw Components.Exception("", Cr.NS_ERROR_ABORT);
+  },
+};
+
+add_task(async function () {
+  info("Test that the default icon has the right content type.");
+  let channel = NetUtil.newChannel({
+    uri: PlacesUtils.favicons.defaultFavicon,
+    loadUsingSystemPrincipal: true,
+    contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_FAVICON,
+  });
+  let listener = new streamListener(
+    PlacesUtils.favicons.defaultFaviconMimeType
+  );
+  channel.asyncOpen(listener);
+  await listener.done.promise;
+});
+
+add_task(async function () {
+  info(
+    "Test icon URI that we don't know anything about.  Will serve the default icon."
+  );
+  let channel = NetUtil.newChannel({
+    uri: PlacesUtils.favicons.getFaviconLinkForIcon(testIconURI).spec,
+    loadUsingSystemPrincipal: true,
+    contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_FAVICON,
+  });
+  let listener = new streamListener(
+    PlacesUtils.favicons.defaultFaviconMimeType
+  );
+  channel.asyncOpen(listener);
+  await listener.done.promise;
+});
+
+add_task(async function () {
+  info("Test that the content type of a favicon we add is correct.");
+  let testURI = uri("http://mozilla.org/");
+  // Add the data before opening
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    testIconURI,
+    testFaviconData,
+    0,
+    systemPrincipal
+  );
+  await PlacesTestUtils.addVisits(testURI);
+  await setFaviconForPage(testURI, testIconURI);
+  // Open the channel
+  let channel = NetUtil.newChannel({
+    uri: PlacesUtils.favicons.getFaviconLinkForIcon(testIconURI).spec,
+    loadUsingSystemPrincipal: true,
+    contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_FAVICON,
+  });
+  let listener = new streamListener("image/png");
+  channel.asyncOpen(listener);
+  await listener.done.promise;
+});
diff --git a/toolkit/components/places/tests/favicons/test_copyFavicons.js b/toolkit/components/places/tests/favicons/test_copyFavicons.js
new file mode 100644
index 0000000000..687b799a4b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_copyFavicons.js
@@ -0,0 +1,166 @@
+const TEST_URI1 = Services.io.newURI("http://mozilla.com/");
+const TEST_URI2 = Services.io.newURI("http://places.com/");
+const TEST_URI3 = Services.io.newURI("http://bookmarked.com/");
+const LOAD_NON_PRIVATE = PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE;
+const LOAD_PRIVATE = PlacesUtils.favicons.FAVICON_LOAD_PRIVATE;
+
+function copyFavicons(source, dest, inPrivate) {
+  return new Promise(resolve => {
+    PlacesUtils.favicons.copyFavicons(
+      source,
+      dest,
+      inPrivate ? LOAD_PRIVATE : LOAD_NON_PRIVATE,
+      resolve
+    );
+  });
+}
+
+function promisePageChanged(url) {
+  return PlacesTestUtils.waitForNotification("favicon-changed", events =>
+    events.some(e => e.url == url)
+  );
+}
+
+add_task(async function test_copyFavicons_inputcheck() {
+  Assert.throws(
+    () => PlacesUtils.favicons.copyFavicons(null, TEST_URI2, LOAD_PRIVATE),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => PlacesUtils.favicons.copyFavicons(TEST_URI1, null, LOAD_PRIVATE),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => PlacesUtils.favicons.copyFavicons(TEST_URI1, TEST_URI2, 3),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => PlacesUtils.favicons.copyFavicons(TEST_URI1, TEST_URI2, -1),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => PlacesUtils.favicons.copyFavicons(TEST_URI1, TEST_URI2, null),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+});
+
+add_task(async function test_copyFavicons_noop() {
+  info("Unknown uris");
+  Assert.equal(
+    await copyFavicons(TEST_URI1, TEST_URI2, false),
+    null,
+    "Icon should not have been copied"
+  );
+
+  info("Unknown dest uri");
+  await PlacesTestUtils.addVisits(TEST_URI1);
+  Assert.equal(
+    await copyFavicons(TEST_URI1, TEST_URI2, false),
+    null,
+    "Icon should not have been copied"
+  );
+
+  info("Unknown dest uri");
+  await PlacesTestUtils.addVisits(TEST_URI1);
+  Assert.equal(
+    await copyFavicons(TEST_URI1, TEST_URI2, false),
+    null,
+    "Icon should not have been copied"
+  );
+
+  info("Unknown dest uri, source has icon");
+  await setFaviconForPage(TEST_URI1, SMALLPNG_DATA_URI);
+  Assert.equal(
+    await copyFavicons(TEST_URI1, TEST_URI2, false),
+    null,
+    "Icon should not have been copied"
+  );
+
+  info("Known uris, source has icon, private");
+  await PlacesTestUtils.addVisits(TEST_URI2);
+  Assert.equal(
+    await copyFavicons(TEST_URI1, TEST_URI2, true),
+    null,
+    "Icon should not have been copied"
+  );
+
+  PlacesUtils.favicons.expireAllFavicons();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_copyFavicons() {
+  info("Normal copy across 2 pages");
+  await PlacesTestUtils.addVisits(TEST_URI1);
+  await setFaviconForPage(TEST_URI1, SMALLPNG_DATA_URI);
+  await setFaviconForPage(TEST_URI1, SMALLSVG_DATA_URI);
+  await PlacesTestUtils.addVisits(TEST_URI2);
+  let promiseChange = promisePageChanged(TEST_URI2.spec);
+  Assert.equal(
+    (await copyFavicons(TEST_URI1, TEST_URI2, false)).spec,
+    SMALLSVG_DATA_URI.spec,
+    "Icon should have been copied"
+  );
+  await promiseChange;
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI2, 1),
+    SMALLPNG_DATA_URI.spec,
+    "Small icon found"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI2),
+    SMALLSVG_DATA_URI.spec,
+    "Large icon found"
+  );
+
+  info("Private copy to a bookmarked page");
+  await PlacesUtils.bookmarks.insert({
+    url: TEST_URI3,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  promiseChange = promisePageChanged(TEST_URI3.spec);
+  Assert.equal(
+    (await copyFavicons(TEST_URI1, TEST_URI3, true)).spec,
+    SMALLSVG_DATA_URI.spec,
+    "Icon should have been copied"
+  );
+  await promiseChange;
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI3, 1),
+    SMALLPNG_DATA_URI.spec,
+    "Small icon found"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI3),
+    SMALLSVG_DATA_URI.spec,
+    "Large icon found"
+  );
+
+  PlacesUtils.favicons.expireAllFavicons();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_copyFavicons_overlap() {
+  info("Copy to a page that has one of the favicons already");
+  await PlacesTestUtils.addVisits(TEST_URI1);
+  await setFaviconForPage(TEST_URI1, SMALLPNG_DATA_URI);
+  await setFaviconForPage(TEST_URI1, SMALLSVG_DATA_URI);
+  await PlacesTestUtils.addVisits(TEST_URI2);
+  await setFaviconForPage(TEST_URI2, SMALLPNG_DATA_URI);
+  let promiseChange = promisePageChanged(TEST_URI2.spec);
+  Assert.equal(
+    (await copyFavicons(TEST_URI1, TEST_URI2, false)).spec,
+    SMALLSVG_DATA_URI.spec,
+    "Icon should have been copied"
+  );
+  await promiseChange;
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI2, 1),
+    SMALLPNG_DATA_URI.spec,
+    "Small icon found"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URI2),
+    SMALLSVG_DATA_URI.spec,
+    "Large icon found"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_expireAllFavicons.js b/toolkit/components/places/tests/favicons/test_expireAllFavicons.js
new file mode 100644
index 0000000000..73c3ca6e4b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_expireAllFavicons.js
@@ -0,0 +1,38 @@
+/**
+ * This file tests that favicons are correctly expired by expireAllFavicons.
+ */
+
+"use strict";
+
+const TEST_PAGE_URI = NetUtil.newURI("http://example.com/");
+const BOOKMARKED_PAGE_URI = NetUtil.newURI("http://example.com/bookmarked");
+
+add_task(async function test_expireAllFavicons() {
+  // Add a visited page.
+  await PlacesTestUtils.addVisits({
+    uri: TEST_PAGE_URI,
+    transition: TRANSITION_TYPED,
+  });
+
+  // Set a favicon for our test page.
+  await setFaviconForPage(TEST_PAGE_URI, SMALLPNG_DATA_URI);
+
+  // Add a page with a bookmark.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: BOOKMARKED_PAGE_URI,
+    title: "Test bookmark",
+  });
+
+  // Set a favicon for our bookmark.
+  await setFaviconForPage(BOOKMARKED_PAGE_URI, SMALLPNG_DATA_URI);
+
+  // Start expiration only after data has been saved in the database.
+  let promise = promiseTopicObserved(PlacesUtils.TOPIC_FAVICONS_EXPIRED);
+  PlacesUtils.favicons.expireAllFavicons();
+  await promise;
+
+  // Check that the favicons for the pages we added were removed.
+  await promiseFaviconMissingForPage(TEST_PAGE_URI);
+  await promiseFaviconMissingForPage(BOOKMARKED_PAGE_URI);
+});
diff --git a/toolkit/components/places/tests/favicons/test_expire_migrated_icons.js b/toolkit/components/places/tests/favicons/test_expire_migrated_icons.js
new file mode 100644
index 0000000000..00516a2a0b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_expire_migrated_icons.js
@@ -0,0 +1,30 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests that favicons migrated from a previous profile, having a 0
+ * expiration, will be properly expired when fetching new ones.
+ */
+
+add_task(async function test_storing_a_normal_16x16_icon() {
+  const PAGE_URL = "http://places.test";
+  await PlacesTestUtils.addVisits(PAGE_URL);
+  await setFaviconForPage(PAGE_URL, SMALLPNG_DATA_URI);
+
+  // Now set expiration to 0 and change the payload.
+  info("Set expiration to 0 and replace favicon data");
+  await PlacesUtils.withConnectionWrapper("Change favicons payload", db => {
+    return db.execute(`UPDATE moz_icons SET expire_ms = 0, data = "test"`);
+  });
+
+  let { data, mimeType } = await getFaviconDataForPage(PAGE_URL);
+  Assert.equal(mimeType, "image/png");
+  Assert.deepEqual(
+    data,
+    "test".split("").map(c => c.charCodeAt(0))
+  );
+
+  info("Refresh favicon");
+  await setFaviconForPage(PAGE_URL, SMALLPNG_DATA_URI, false);
+  await compareFavicons("page-icon:" + PAGE_URL, SMALLPNG_DATA_URI);
+});
diff --git a/toolkit/components/places/tests/favicons/test_expire_on_new_icons.js b/toolkit/components/places/tests/favicons/test_expire_on_new_icons.js
new file mode 100644
index 0000000000..d5a7c42ba3
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_expire_on_new_icons.js
@@ -0,0 +1,151 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that adding new icons for a page expired old ones.
+ */
+
+add_task(async function test_expire_associated() {
+  const TEST_URL = "http://mozilla.com/";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  const TEST_URL2 = "http://test.mozilla.com/";
+  await PlacesTestUtils.addVisits(TEST_URL2);
+
+  let favicons = [
+    {
+      name: "favicon-normal16.png",
+      mimeType: "image/png",
+      expired: true,
+    },
+    {
+      name: "favicon-normal32.png",
+      mimeType: "image/png",
+    },
+    {
+      name: "favicon-big64.png",
+      mimeType: "image/png",
+    },
+  ];
+
+  for (let icon of favicons) {
+    let data = readFileData(do_get_file(icon.name));
+    PlacesUtils.favicons.replaceFaviconData(
+      NetUtil.newURI(TEST_URL + icon.name),
+      data,
+      icon.mimeType
+    );
+    await setFaviconForPage(TEST_URL, TEST_URL + icon.name);
+    if (icon.expired) {
+      await expireIconRelationsForPage(TEST_URL);
+      // Add the same icon to another page.
+      PlacesUtils.favicons.replaceFaviconData(
+        NetUtil.newURI(TEST_URL + icon.name),
+        data,
+        icon.mimeType,
+        icon.expire
+      );
+      await setFaviconForPage(TEST_URL2, TEST_URL + icon.name);
+    }
+  }
+
+  // Only the second and the third icons should have survived.
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URL, 16),
+    TEST_URL + favicons[1].name,
+    "Should retrieve the 32px icon, not the 16px one."
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URL, 64),
+    TEST_URL + favicons[2].name,
+    "Should retrieve the 64px icon"
+  );
+
+  // The expired icon for page 2 should have survived.
+  Assert.equal(
+    await getFaviconUrlForPage(TEST_URL2, 16),
+    TEST_URL + favicons[0].name,
+    "Should retrieve the expired 16px icon"
+  );
+});
+
+add_task(async function test_expire_root() {
+  async function countEntries(tablename) {
+    await PlacesTestUtils.promiseAsyncUpdates();
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute("SELECT * FROM " + tablename);
+    return rows.length;
+  }
+
+  // Clear the database.
+  let promise = promiseTopicObserved(PlacesUtils.TOPIC_FAVICONS_EXPIRED);
+  PlacesUtils.favicons.expireAllFavicons();
+  await promise;
+
+  Assert.equal(await countEntries("moz_icons"), 0, "There should be no icons");
+
+  let pageURI = NetUtil.newURI("http://root.mozilla.com/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  // Insert an expired icon.
+  let iconURI = NetUtil.newURI(pageURI.spec + "favicon-normal16.png");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    iconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, iconURI);
+  Assert.equal(
+    await countEntries("moz_icons_to_pages"),
+    1,
+    "There should be 1 association"
+  );
+  // Set an expired time on the icon-page relation.
+  await expireIconRelationsForPage(pageURI.spec);
+
+  // Now insert a new root icon.
+  let rootIconURI = NetUtil.newURI(pageURI.spec + "favicon.ico");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    rootIconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, rootIconURI);
+
+  // Only the root icon should have survived.
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI, 16),
+    rootIconURI.spec,
+    "Should retrieve the root icon."
+  );
+  Assert.equal(
+    await countEntries("moz_icons_to_pages"),
+    0,
+    "There should be no associations"
+  );
+});
+
+async function expireIconRelationsForPage(url) {
+  // Set an expired time on the icon-page relation.
+  await PlacesUtils.withConnectionWrapper("expireFavicon", async db => {
+    await db.execute(
+      `
+      UPDATE moz_icons_to_pages SET expire_ms = 0
+      WHERE page_id = (SELECT id FROM moz_pages_w_icons WHERE page_url = :url)
+      `,
+      { url }
+    );
+    // Also ensure the icon is not expired, here we should only replace entries
+    // based on their association expiration, not the icon expiration.
+    let count = (
+      await db.execute(
+        `
+        SELECT count(*) FROM moz_icons
+        WHERE expire_ms < strftime('%s','now','localtime','utc') * 1000
+        `
+      )
+    )[0].getResultByIndex(0);
+    Assert.equal(count, 0, "All the icons should have future expiration");
+  });
+}
diff --git a/toolkit/components/places/tests/favicons/test_favicons_conversions.js b/toolkit/components/places/tests/favicons/test_favicons_conversions.js
new file mode 100644
index 0000000000..28a0fffb7f
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_favicons_conversions.js
@@ -0,0 +1,192 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests the image conversions done by the favicon service.
+ */
+
+// Globals
+
+// The pixel values we get on Windows are sometimes +/- 1 value compared to
+// other platforms, so we need to skip some image content tests.
+var isWindows = "@mozilla.org/windows-registry-key;1" in Cc;
+
+/**
+ * Checks the conversion of the given test image file.
+ *
+ * @param aFileName
+ *        File that contains the favicon image, located in the test folder.
+ * @param aFileMimeType
+ *        MIME type of the image contained in the file.
+ * @param aFileLength
+ *        Expected length of the file.
+ * @param aExpectConversion
+ *        If false, the icon should be stored as is.  If true, the expected data
+ *        is loaded from a file named "expected-" + aFileName + ".png".
+ * @param aVaryOnWindows
+ *        Indicates that the content of the converted image can be different on
+ *        Windows and should not be checked on that platform.
+ * @param aCallback
+ *        This function is called after the check finished.
+ */
+async function checkFaviconDataConversion(
+  aFileName,
+  aFileMimeType,
+  aFileLength,
+  aExpectConversion,
+  aVaryOnWindows
+) {
+  let pageURI = NetUtil.newURI("http://places.test/page/" + aFileName);
+  await PlacesTestUtils.addVisits({
+    uri: pageURI,
+    transition: TRANSITION_TYPED,
+  });
+  let faviconURI = NetUtil.newURI("http://places.test/icon/" + aFileName);
+  let fileData = readFileOfLength(aFileName, aFileLength);
+
+  PlacesUtils.favicons.replaceFaviconData(faviconURI, fileData, aFileMimeType);
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      pageURI,
+      faviconURI,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      (aURI, aDataLen, aData, aMimeType) => {
+        if (!aExpectConversion) {
+          Assert.ok(compareArrays(aData, fileData));
+          Assert.equal(aMimeType, aFileMimeType);
+        } else {
+          if (!aVaryOnWindows || !isWindows) {
+            let expectedFile = do_get_file("expected-" + aFileName + ".png");
+            Assert.ok(compareArrays(aData, readFileData(expectedFile)));
+          }
+          Assert.equal(aMimeType, "image/png");
+        }
+        resolve();
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+}
+
+add_task(async function test_storing_a_normal_16x16_icon() {
+  // 16x16 png, 286 bytes.
+  // optimized: no
+  await checkFaviconDataConversion(
+    "favicon-normal16.png",
+    "image/png",
+    286,
+    false,
+    false
+  );
+});
+
+add_task(async function test_storing_a_normal_32x32_icon() {
+  // 32x32 png, 344 bytes.
+  // optimized: no
+  await checkFaviconDataConversion(
+    "favicon-normal32.png",
+    "image/png",
+    344,
+    false,
+    false
+  );
+});
+
+add_task(async function test_storing_a_big_16x16_icon() {
+  //  in: 16x16 ico, 1406 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-big16.ico",
+    "image/x-icon",
+    1406,
+    true,
+    false
+  );
+});
+
+add_task(async function test_storing_an_oversize_4x4_icon() {
+  //  in: 4x4 jpg, 4751 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-big4.jpg",
+    "image/jpeg",
+    4751,
+    true,
+    false
+  );
+});
+
+add_task(async function test_storing_an_oversize_32x32_icon() {
+  //  in: 32x32 jpg, 3494 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-big32.jpg",
+    "image/jpeg",
+    3494,
+    true,
+    true
+  );
+});
+
+add_task(async function test_storing_an_oversize_48x48_icon() {
+  //  in: 48x48 ico, 56646 bytes.
+  // (howstuffworks.com icon, contains 13 icons with sizes from 16x16 to
+  // 48x48 in varying depths)
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-big48.ico",
+    "image/x-icon",
+    56646,
+    true,
+    false
+  );
+});
+
+add_task(async function test_storing_an_oversize_64x64_icon() {
+  //  in: 64x64 png, 10698 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-big64.png",
+    "image/png",
+    10698,
+    true,
+    false
+  );
+});
+
+add_task(async function test_scaling_an_oversize_160x3_icon() {
+  //  in: 160x3 jpg, 5095 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-scale160x3.jpg",
+    "image/jpeg",
+    5095,
+    true,
+    false
+  );
+});
+
+add_task(async function test_scaling_an_oversize_3x160_icon() {
+  //  in: 3x160 jpg, 5059 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-scale3x160.jpg",
+    "image/jpeg",
+    5059,
+    true,
+    false
+  );
+});
+
+add_task(async function test_animated_16x16_icon() {
+  // in: 16x16 apng, 1791 bytes.
+  // optimized: yes
+  await checkFaviconDataConversion(
+    "favicon-animated16.png",
+    "image/png",
+    1791,
+    true,
+    false
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_favicons_protocols_ref.js b/toolkit/components/places/tests/favicons/test_favicons_protocols_ref.js
new file mode 100644
index 0000000000..aa0241a3d2
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_favicons_protocols_ref.js
@@ -0,0 +1,114 @@
+/**
+ * This file tests the size ref on the icons protocols.
+ */
+
+const PAGE_URL = "http://icon.mozilla.org/";
+const ICON16_URL = "http://places.test/favicon-normal16.png";
+const ICON32_URL = "http://places.test/favicon-normal32.png";
+
+add_task(async function () {
+  await PlacesTestUtils.addVisits(PAGE_URL);
+  // Add 2 differently sized favicons for this page.
+
+  let data = readFileData(do_get_file("favicon-normal16.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    Services.io.newURI(ICON16_URL),
+    data,
+    "image/png"
+  );
+  await setFaviconForPage(PAGE_URL, ICON16_URL);
+  data = readFileData(do_get_file("favicon-normal32.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    Services.io.newURI(ICON32_URL),
+    data,
+    "image/png"
+  );
+  await setFaviconForPage(PAGE_URL, ICON32_URL);
+
+  const PAGE_ICON_URL = "page-icon:" + PAGE_URL;
+
+  await compareFavicons(
+    PAGE_ICON_URL,
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Not specifying a ref should return the bigger icon"
+  );
+  // Fake window object.
+  let win = { devicePixelRatio: 1.0 };
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 16),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON16_URL)),
+    "Size=16 should return the 16px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 32),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=32 should return the 32px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 33),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=33 should return the 32px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 17),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=17 should return the 32px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 1),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON16_URL)),
+    "Size=1 should return the 16px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 0),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=0 should return the bigger icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, -1),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Invalid size should return the bigger icon"
+  );
+
+  // Add the icon also for the page with ref.
+  await PlacesTestUtils.addVisits(PAGE_URL + "#other§=12");
+  await setFaviconForPage(PAGE_URL + "#other§=12", ICON16_URL, false);
+  await setFaviconForPage(PAGE_URL + "#other§=12", ICON32_URL, false);
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL + "#other§=12", 16),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON16_URL)),
+    "Pre-existing refs should be retained"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL + "#other§=12", 32),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Pre-existing refs should be retained"
+  );
+
+  // If the ref-ed url is unknown, should still try to fetch icon for the unref-ed url.
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL + "#randomstuff", 32),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Non-existing refs should be ignored"
+  );
+
+  win = { devicePixelRatio: 1.1 };
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 16),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=16 with HIDPI should return the 32px icon"
+  );
+  await compareFavicons(
+    PlacesUtils.urlWithSizeRef(win, PAGE_ICON_URL, 32),
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON32_URL)),
+    "Size=32 with HIDPI should return the 32px icon"
+  );
+
+  // Check setting a different default preferred size works.
+  PlacesUtils.favicons.setDefaultIconURIPreferredSize(16);
+  await compareFavicons(
+    PAGE_ICON_URL,
+    PlacesUtils.favicons.getFaviconLinkForIcon(Services.io.newURI(ICON16_URL)),
+    "Not specifying a ref should return the set default size icon"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_getFaviconDataForPage.js b/toolkit/components/places/tests/favicons/test_getFaviconDataForPage.js
new file mode 100644
index 0000000000..80f498f33f
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_getFaviconDataForPage.js
@@ -0,0 +1,131 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const FAVICON_URI = NetUtil.newURI(do_get_file("favicon-normal32.png"));
+const FAVICON_DATA = readFileData(do_get_file("favicon-normal32.png"));
+const FAVICON_MIMETYPE = "image/png";
+const ICON32_URL = "http://places.test/favicon-normal32.png";
+
+add_task(async function test_normal() {
+  Assert.equal(FAVICON_DATA.length, 344);
+  let pageURI = NetUtil.newURI("http://example.com/normal");
+
+  await PlacesTestUtils.addVisits(pageURI);
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      pageURI,
+      FAVICON_URI,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function () {
+        PlacesUtils.favicons.getFaviconDataForPage(
+          pageURI,
+          function (aURI, aDataLen, aData, aMimeType) {
+            Assert.ok(aURI.equals(FAVICON_URI));
+            Assert.equal(FAVICON_DATA.length, aDataLen);
+            Assert.ok(compareArrays(FAVICON_DATA, aData));
+            Assert.equal(FAVICON_MIMETYPE, aMimeType);
+            resolve();
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+});
+
+add_task(async function test_missing() {
+  let pageURI = NetUtil.newURI("http://example.com/missing");
+
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      pageURI,
+      function (aURI, aDataLen, aData, aMimeType) {
+        // Check also the expected data types.
+        Assert.ok(aURI === null);
+        Assert.ok(aDataLen === 0);
+        Assert.ok(aData.length === 0);
+        Assert.ok(aMimeType === "");
+        resolve();
+      }
+    );
+  });
+});
+
+add_task(async function test_fallback() {
+  const ROOT_URL = "https://www.example.com/";
+  const ROOT_ICON_URL = ROOT_URL + "favicon.ico";
+  const SUBPAGE_URL = ROOT_URL + "/missing";
+
+  info("Set icon for the root");
+  await PlacesTestUtils.addVisits(ROOT_URL);
+  let data = readFileData(do_get_file("favicon-normal16.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    NetUtil.newURI(ROOT_ICON_URL),
+    data,
+    "image/png"
+  );
+  await setFaviconForPage(ROOT_URL, ROOT_ICON_URL);
+
+  info("check fallback icons");
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      NetUtil.newURI(ROOT_URL),
+      (aURI, aDataLen, aData, aMimeType) => {
+        Assert.equal(aURI.spec, ROOT_ICON_URL);
+        Assert.equal(aDataLen, data.length);
+        Assert.deepEqual(aData, data);
+        Assert.equal(aMimeType, "image/png");
+        resolve();
+      }
+    );
+  });
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      NetUtil.newURI(SUBPAGE_URL),
+      (aURI, aDataLen, aData, aMimeType) => {
+        Assert.equal(aURI.spec, ROOT_ICON_URL);
+        Assert.equal(aDataLen, data.length);
+        Assert.deepEqual(aData, data);
+        Assert.equal(aMimeType, "image/png");
+        resolve();
+      }
+    );
+  });
+
+  info("Now add a proper icon for the page");
+  await PlacesTestUtils.addVisits(SUBPAGE_URL);
+  let data32 = readFileData(do_get_file("favicon-normal32.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    NetUtil.newURI(ICON32_URL),
+    data32,
+    "image/png"
+  );
+  await setFaviconForPage(SUBPAGE_URL, ICON32_URL);
+
+  info("check no fallback icons");
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      NetUtil.newURI(ROOT_URL),
+      (aURI, aDataLen, aData, aMimeType) => {
+        Assert.equal(aURI.spec, ROOT_ICON_URL);
+        Assert.equal(aDataLen, data.length);
+        Assert.deepEqual(aData, data);
+        Assert.equal(aMimeType, "image/png");
+        resolve();
+      }
+    );
+  });
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      NetUtil.newURI(SUBPAGE_URL),
+      (aURI, aDataLen, aData, aMimeType) => {
+        Assert.equal(aURI.spec, ICON32_URL);
+        Assert.equal(aDataLen, data32.length);
+        Assert.deepEqual(aData, data32);
+        Assert.equal(aMimeType, "image/png");
+        resolve();
+      }
+    );
+  });
+});
diff --git a/toolkit/components/places/tests/favicons/test_getFaviconLinkForIcon.js b/toolkit/components/places/tests/favicons/test_getFaviconLinkForIcon.js
new file mode 100644
index 0000000000..e60a59bd80
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_getFaviconLinkForIcon.js
@@ -0,0 +1,35 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test getFaviconLinkForIcon API.
+ */
+
+add_task(async function test_basic() {
+  // Check these protocols are pass-through.
+  for (let protocol of ["http://", "https://"]) {
+    let url = PlacesUtils.favicons.getFaviconLinkForIcon(
+      Services.io.newURI(protocol + "test/test.png")
+    ).spec;
+    Assert.equal(url, "cached-favicon:" + protocol + "test/test.png");
+  }
+});
+
+add_task(async function test_directRequestProtocols() {
+  // Check these protocols are pass-through.
+  for (let protocol of [
+    "about:",
+    "cached-favicon:",
+    "chrome://",
+    "data:",
+    "file:///",
+    "moz-page-thumb://",
+    "page-icon:",
+    "resource://",
+  ]) {
+    let url = PlacesUtils.favicons.getFaviconLinkForIcon(
+      Services.io.newURI(protocol + "test/test.png")
+    ).spec;
+    Assert.equal(url, protocol + "test/test.png");
+  }
+});
diff --git a/toolkit/components/places/tests/favicons/test_getFaviconURLForPage.js b/toolkit/components/places/tests/favicons/test_getFaviconURLForPage.js
new file mode 100644
index 0000000000..e8f459cb08
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_getFaviconURLForPage.js
@@ -0,0 +1,101 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const ICON32_URL = "http://places.test/favicon-normal32.png";
+
+add_task(async function test_normal() {
+  let pageURI = NetUtil.newURI("http://example.com/normal");
+
+  await PlacesTestUtils.addVisits(pageURI);
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      pageURI,
+      SMALLPNG_DATA_URI,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function () {
+        PlacesUtils.favicons.getFaviconURLForPage(
+          pageURI,
+          function (aURI, aDataLen, aData, aMimeType) {
+            Assert.ok(aURI.equals(SMALLPNG_DATA_URI));
+
+            // Check also the expected data types.
+            Assert.ok(aDataLen === 0);
+            Assert.ok(aData.length === 0);
+            Assert.ok(aMimeType === "");
+            resolve();
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+});
+
+add_task(async function test_missing() {
+  let pageURI = NetUtil.newURI("http://example.com/missing");
+
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconURLForPage(
+      pageURI,
+      function (aURI, aDataLen, aData, aMimeType) {
+        // Check also the expected data types.
+        Assert.ok(aURI === null);
+        Assert.ok(aDataLen === 0);
+        Assert.ok(aData.length === 0);
+        Assert.ok(aMimeType === "");
+        resolve();
+      }
+    );
+  });
+});
+
+add_task(async function test_fallback() {
+  const ROOT_URL = "https://www.example.com/";
+  const ROOT_ICON_URL = ROOT_URL + "favicon.ico";
+  const SUBPAGE_URL = ROOT_URL + "/missing";
+
+  info("Set icon for the root");
+  await PlacesTestUtils.addVisits(ROOT_URL);
+  let data = readFileData(do_get_file("favicon-normal16.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    NetUtil.newURI(ROOT_ICON_URL),
+    data,
+    "image/png"
+  );
+  await setFaviconForPage(ROOT_URL, ROOT_ICON_URL);
+
+  info("check fallback icons");
+  Assert.equal(
+    await getFaviconUrlForPage(ROOT_URL),
+    ROOT_ICON_URL,
+    "The root should have its favicon"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(SUBPAGE_URL),
+    ROOT_ICON_URL,
+    "The page should fallback to the root icon"
+  );
+
+  info("Now add a proper icon for the page");
+  await PlacesTestUtils.addVisits(SUBPAGE_URL);
+  let data32 = readFileData(do_get_file("favicon-normal32.png"));
+  PlacesUtils.favicons.replaceFaviconData(
+    NetUtil.newURI(ICON32_URL),
+    data32,
+    "image/png"
+  );
+  await setFaviconForPage(SUBPAGE_URL, ICON32_URL);
+
+  info("check no fallback icons");
+  Assert.equal(
+    await getFaviconUrlForPage(ROOT_URL),
+    ROOT_ICON_URL,
+    "The root should still have its favicon"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(SUBPAGE_URL),
+    ICON32_URL,
+    "The page should also have its icon"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_heavy_favicon.js b/toolkit/components/places/tests/favicons/test_heavy_favicon.js
new file mode 100644
index 0000000000..09adcaf6fa
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_heavy_favicon.js
@@ -0,0 +1,36 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests a png with a large file size that can't fit MAX_FAVICON_BUFFER_SIZE,
+ * it should be downsized until it can be stored, rather than thrown away.
+ */
+
+add_task(async function () {
+  let file = do_get_file("noise.png");
+  let icon = {
+    file,
+    uri: NetUtil.newURI(file),
+    data: readFileData(file),
+    mimetype: "image/png",
+  };
+
+  // If this should fail, it means MAX_FAVICON_BUFFER_SIZE has been made bigger
+  // than this icon. For this test to make sense the icon shoul always be
+  // bigger than MAX_FAVICON_BUFFER_SIZE. Please update the icon!
+  Assert.ok(
+    icon.data.length > Ci.nsIFaviconService.MAX_FAVICON_BUFFER_SIZE,
+    "The test icon file size must be larger than Ci.nsIFaviconService.MAX_FAVICON_BUFFER_SIZE"
+  );
+
+  let pageURI = uri("http://foo.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  PlacesUtils.favicons.replaceFaviconData(icon.uri, icon.data, icon.mimetype);
+  await setFaviconForPage(pageURI, icon.uri);
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI),
+    icon.uri.spec,
+    "A resampled version of the icon should be stored"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_incremental_vacuum.js b/toolkit/components/places/tests/favicons/test_incremental_vacuum.js
new file mode 100644
index 0000000000..ab93121d47
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_incremental_vacuum.js
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests incremental vacuum of the favicons database.
+
+const { PlacesDBUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesDBUtils.sys.mjs"
+);
+
+add_task(async function () {
+  let icon = {
+    file: do_get_file("noise.png"),
+    mimetype: "image/png",
+  };
+
+  let url = "http://foo.bar/";
+  await PlacesTestUtils.addVisits(url);
+  for (let i = 0; i < 10; ++i) {
+    let iconUri = NetUtil.newURI("http://mozilla.org/" + i);
+    let data = readFileData(icon.file);
+    PlacesUtils.favicons.replaceFaviconData(iconUri, data, icon.mimetype);
+    await setFaviconForPage(url, iconUri);
+  }
+
+  let promise = TestUtils.topicObserved("places-favicons-expired");
+  PlacesUtils.favicons.expireAllFavicons();
+  await promise;
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let state = (
+    await db.execute("PRAGMA favicons.auto_vacuum")
+  )[0].getResultByIndex(0);
+  Assert.equal(state, 2, "auto_vacuum should be incremental");
+  let count = (
+    await db.execute("PRAGMA favicons.freelist_count")
+  )[0].getResultByIndex(0);
+  info(`Found ${count} freelist pages`);
+  let log = await PlacesDBUtils.incrementalVacuum();
+  info(log);
+  let newCount = (
+    await db.execute("PRAGMA favicons.freelist_count")
+  )[0].getResultByIndex(0);
+  info(`Found ${newCount} freelist pages`);
+  Assert.ok(
+    newCount < count,
+    "The number of freelist pages should have reduced"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_multiple_frames.js b/toolkit/components/places/tests/favicons/test_multiple_frames.js
new file mode 100644
index 0000000000..5c7f585715
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_multiple_frames.js
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests support for icons with multiple frames (like .ico files).
+ */
+
+add_task(async function () {
+  //  in: 48x48 ico, 56646 bytes.
+  // (howstuffworks.com icon, contains 13 icons with sizes from 16x16 to
+  // 48x48 in varying depths)
+  let pageURI = NetUtil.newURI("http://places.test/page/");
+  await PlacesTestUtils.addVisits(pageURI);
+  let faviconURI = NetUtil.newURI("http://places.test/icon/favicon-multi.ico");
+  // Fake window.
+  let win = { devicePixelRatio: 1.0 };
+  let icoData = readFileData(do_get_file("favicon-multi.ico"));
+  PlacesUtils.favicons.replaceFaviconData(faviconURI, icoData, "image/x-icon");
+  await setFaviconForPage(pageURI, faviconURI);
+
+  for (let size of [16, 32, 64]) {
+    let file = do_get_file(`favicon-multi-frame${size}.png`);
+    let data = readFileData(file);
+
+    info("Check getFaviconDataForPage");
+    let icon = await getFaviconDataForPage(pageURI, size);
+    Assert.equal(icon.mimeType, "image/png");
+    Assert.deepEqual(icon.data, data);
+
+    info("Check cached-favicon protocol");
+    await compareFavicons(
+      Services.io.newFileURI(file),
+      PlacesUtils.urlWithSizeRef(
+        win,
+        PlacesUtils.favicons.getFaviconLinkForIcon(faviconURI).spec,
+        size
+      )
+    );
+
+    info("Check page-icon protocol");
+    await compareFavicons(
+      Services.io.newFileURI(file),
+      PlacesUtils.urlWithSizeRef(win, "page-icon:" + pageURI.spec, size)
+    );
+  }
+});
diff --git a/toolkit/components/places/tests/favicons/test_page-icon_protocol.js b/toolkit/components/places/tests/favicons/test_page-icon_protocol.js
new file mode 100644
index 0000000000..932040bafb
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_page-icon_protocol.js
@@ -0,0 +1,243 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const ICON_DATAURL =
+  "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAAAAAA6fptVAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJggg==";
+const TEST_URI = NetUtil.newURI("http://mozilla.org/");
+const ICON_URI = NetUtil.newURI("http://mozilla.org/favicon.ico");
+
+const { XPCShellContentUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/XPCShellContentUtils.sys.mjs"
+);
+
+const PAGE_ICON_TEST_URLS = [
+  "page-icon:http://example.com/",
+  "page-icon:http://a-site-never-before-seen.test",
+  // For the following, the page-icon protocol is expected to successfully
+  // return the default favicon.
+  "page-icon:test",
+  "page-icon:",
+  "page-icon:chrome://something.html",
+  "page-icon:foo://bar/baz",
+];
+
+XPCShellContentUtils.init(this);
+
+const HTML = String.raw`<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+</head>
+<body>
+  Hello from example.com!
+</body>
+</html>`;
+
+const server = XPCShellContentUtils.createHttpServer({
+  hosts: ["example.com"],
+});
+
+server.registerPathHandler("/", (request, response) => {
+  response.setHeader("Content-Type", "text/html");
+  response.write(HTML);
+});
+
+function fetchIconForSpec(spec) {
+  return new Promise((resolve, reject) => {
+    NetUtil.asyncFetch(
+      {
+        uri: NetUtil.newURI(spec),
+        loadUsingSystemPrincipal: true,
+        contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_FAVICON,
+      },
+      (input, status, request) => {
+        if (!Components.isSuccessCode(status)) {
+          reject(new Error("unable to load icon"));
+          return;
+        }
+
+        try {
+          let data = NetUtil.readInputStreamToString(input, input.available());
+          let contentType = request.QueryInterface(Ci.nsIChannel).contentType;
+          input.close();
+          resolve({ data, contentType });
+        } catch (ex) {
+          reject(ex);
+        }
+      }
+    );
+  });
+}
+
+var gDefaultFavicon;
+var gFavicon;
+
+add_task(async function setup() {
+  await PlacesTestUtils.addVisits(TEST_URI);
+
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    ICON_URI,
+    ICON_DATAURL,
+    (Date.now() + 8640000) * 1000,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      TEST_URI,
+      ICON_URI,
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      resolve,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  gDefaultFavicon = await fetchIconForSpec(
+    PlacesUtils.favicons.defaultFavicon.spec
+  );
+  gFavicon = await fetchIconForSpec(ICON_DATAURL);
+});
+
+add_task(async function known_url() {
+  let { data, contentType } = await fetchIconForSpec(
+    "page-icon:" + TEST_URI.spec
+  );
+  Assert.equal(contentType, gFavicon.contentType);
+  Assert.deepEqual(data, gFavicon.data, "Got the favicon data");
+});
+
+add_task(async function unknown_url() {
+  let { data, contentType } = await fetchIconForSpec(
+    "page-icon:http://www.moz.org/"
+  );
+  Assert.equal(contentType, gDefaultFavicon.contentType);
+  Assert.deepEqual(data, gDefaultFavicon.data, "Got the default favicon data");
+});
+
+add_task(async function invalid_url() {
+  let { data, contentType } = await fetchIconForSpec("page-icon:test");
+  Assert.equal(contentType, gDefaultFavicon.contentType);
+  Assert.ok(data == gDefaultFavicon.data, "Got the default favicon data");
+});
+
+add_task(async function subpage_url_fallback() {
+  let { data, contentType } = await fetchIconForSpec(
+    "page-icon:http://mozilla.org/missing"
+  );
+  Assert.equal(contentType, gFavicon.contentType);
+  Assert.deepEqual(data, gFavicon.data, "Got the root favicon data");
+});
+
+add_task(async function svg_icon() {
+  let faviconURI = NetUtil.newURI("http://places.test/favicon.svg");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    faviconURI,
+    SMALLSVG_DATA_URI.spec,
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  await setFaviconForPage(TEST_URI, faviconURI);
+  let svgIcon = await fetchIconForSpec(SMALLSVG_DATA_URI.spec);
+  info(svgIcon.contentType);
+  let pageIcon = await fetchIconForSpec("page-icon:" + TEST_URI.spec);
+  Assert.equal(svgIcon.contentType, pageIcon.contentType);
+  Assert.deepEqual(svgIcon.data, pageIcon.data, "Got the root favicon data");
+});
+
+add_task(async function page_with_ref() {
+  for (let url of [
+    "http://places.test.ref/#myref",
+    "http://places.test.ref/#!&b=16",
+    "http://places.test.ref/#",
+  ]) {
+    await PlacesTestUtils.addVisits(url);
+    await setFaviconForPage(url, ICON_URI, false);
+    let { data, contentType } = await fetchIconForSpec("page-icon:" + url);
+    Assert.equal(contentType, gFavicon.contentType);
+    Assert.deepEqual(data, gFavicon.data, "Got the favicon data");
+    await PlacesUtils.history.remove(url);
+  }
+});
+
+/**
+ * Tests that page-icon does not work in a normal content process.
+ */
+add_task(async function page_content_process() {
+  let contentPage = await XPCShellContentUtils.loadContentPage(
+    "http://example.com/",
+    {
+      remote: true,
+    }
+  );
+  Assert.notEqual(
+    contentPage.browsingContext.currentRemoteType,
+    "privilegedabout"
+  );
+
+  await contentPage.spawn([PAGE_ICON_TEST_URLS], async URLS => {
+    // We expect each of these URLs to produce an error event when
+    // we attempt to load them in this process type.
+    /* global content */
+    for (let url of URLS) {
+      let img = content.document.createElement("img");
+      img.src = url;
+      let imgPromise = new Promise((resolve, reject) => {
+        img.addEventListener("error", e => {
+          Assert.ok(true, "Got expected load error.");
+          resolve();
+        });
+        img.addEventListener("load", e => {
+          Assert.ok(false, "Did not expect a successful load.");
+          reject();
+        });
+      });
+      content.document.body.appendChild(img);
+      await imgPromise;
+    }
+  });
+
+  await contentPage.close();
+});
+
+/**
+ * Tests that page-icon does work for privileged about content process
+ */
+add_task(async function page_privileged_about_content_process() {
+  // about:certificate loads in the privileged about content process.
+  let contentPage = await XPCShellContentUtils.loadContentPage(
+    "about:certificate",
+    {
+      remote: true,
+    }
+  );
+  Assert.equal(
+    contentPage.browsingContext.currentRemoteType,
+    "privilegedabout"
+  );
+
+  await contentPage.spawn([PAGE_ICON_TEST_URLS], async URLS => {
+    // We expect each of these URLs to load correctly in this process
+    // type.
+    for (let url of URLS) {
+      let img = content.document.createElement("img");
+      img.src = url;
+      let imgPromise = new Promise((resolve, reject) => {
+        img.addEventListener("error", e => {
+          Assert.ok(false, "Did not expect an error. ");
+          reject();
+        });
+        img.addEventListener("load", e => {
+          Assert.ok(true, "Got expected load event.");
+          resolve();
+        });
+      });
+      content.document.body.appendChild(img);
+      await imgPromise;
+    }
+  });
+
+  await contentPage.close();
+});
diff --git a/toolkit/components/places/tests/favicons/test_query_result_favicon_changed_on_child.js b/toolkit/components/places/tests/favicons/test_query_result_favicon_changed_on_child.js
new file mode 100644
index 0000000000..4e5c55e50a
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_query_result_favicon_changed_on_child.js
@@ -0,0 +1,153 @@
+/**
+ * Test for bug 451499 <https://bugzilla.mozilla.org/show_bug.cgi?id=451499>:
+ * Wrong folder icon appears on queries.
+ */
+
+"use strict";
+
+add_task(async function test_query_result_favicon_changed_on_child() {
+  // Bookmark our test page, so it will appear in the query resultset.
+  const PAGE_URI = Services.io.newURI("http://example.com/test_query_result");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "test_bookmark",
+    url: PAGE_URI,
+  });
+
+  // Get the last 10 bookmarks added to the menu or the toolbar.
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+  ]);
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  options.maxResults = 10;
+  options.excludeQueries = 1;
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let resultObserver = {
+    containerStateChanged(aContainerNode, aOldState, aNewState) {
+      if (aNewState == Ci.nsINavHistoryContainerResultNode.STATE_OPENED) {
+        // We set a favicon on PAGE_URI while the container is open.  The
+        // favicon for the page must have data associated with it in order for
+        // the icon changed notifications to be sent, so we use a valid image
+        // data URI.
+        PlacesUtils.favicons.setAndFetchFaviconForPage(
+          PAGE_URI,
+          SMALLPNG_DATA_URI,
+          false,
+          PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+          null,
+          Services.scriptSecurityManager.getSystemPrincipal()
+        );
+      }
+    },
+    nodeIconChanged(aNode) {
+      if (PlacesUtils.nodeIsContainer(aNode)) {
+        do_throw(
+          "The icon should be set only for the page," +
+            " not for the containing query."
+        );
+      }
+    },
+  };
+  Object.setPrototypeOf(resultObserver, NavHistoryResultObserver.prototype);
+  result.addObserver(resultObserver);
+
+  // Open the container and wait for containerStateChanged. We should start
+  // observing before setting |containerOpen| as that's caused by the
+  // setAndFetchFaviconForPage() call caused by the containerStateChanged
+  // observer above.
+  let promise = promiseFaviconChanged(PAGE_URI, SMALLPNG_DATA_URI);
+  result.root.containerOpen = true;
+  await promise;
+
+  // We must wait for the asynchronous database thread to finish the
+  // operation, and then for the main thread to process any pending
+  // notifications that came from the asynchronous thread, before we can be
+  // sure that nodeIconChanged was not invoked in the meantime.
+  await PlacesTestUtils.promiseAsyncUpdates();
+  result.removeObserver(resultObserver);
+
+  // Free the resources immediately.
+  result.root.containerOpen = false;
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(
+  async function test_query_result_favicon_changed_not_affect_lastmodified() {
+    // Bookmark our test page, so it will appear in the query resultset.
+    const PAGE_URI2 = Services.io.newURI(
+      "http://example.com/test_query_result"
+    );
+    let bm = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      title: "test_bookmark",
+      url: PAGE_URI2,
+    });
+
+    let result = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.menuGuid);
+
+    Assert.equal(
+      result.root.childCount,
+      1,
+      "Should have only one item in the query"
+    );
+    Assert.equal(
+      result.root.getChild(0).uri,
+      PAGE_URI2.spec,
+      "Should have the correct child"
+    );
+    Assert.equal(
+      result.root.getChild(0).lastModified,
+      PlacesUtils.toPRTime(bm.lastModified),
+      "Should have the expected last modified date."
+    );
+
+    let promise = promiseFaviconChanged(PAGE_URI2, SMALLPNG_DATA_URI);
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      PAGE_URI2,
+      SMALLPNG_DATA_URI,
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      null,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+    await promise;
+
+    // Open the container and wait for containerStateChanged. We should start
+    // observing before setting |containerOpen| as that's caused by the
+    // setAndFetchFaviconForPage() call caused by the containerStateChanged
+    // observer above.
+
+    // We must wait for the asynchronous database thread to finish the
+    // operation, and then for the main thread to process any pending
+    // notifications that came from the asynchronous thread, before we can be
+    // sure that nodeIconChanged was not invoked in the meantime.
+    await PlacesTestUtils.promiseAsyncUpdates();
+
+    Assert.equal(
+      result.root.childCount,
+      1,
+      "Should have only one item in the query"
+    );
+    Assert.equal(
+      result.root.getChild(0).uri,
+      PAGE_URI2.spec,
+      "Should have the correct child"
+    );
+    Assert.equal(
+      result.root.getChild(0).lastModified,
+      PlacesUtils.toPRTime(bm.lastModified),
+      "Should not have changed the last modified date."
+    );
+
+    // Free the resources immediately.
+    result.root.containerOpen = false;
+  }
+);
diff --git a/toolkit/components/places/tests/favicons/test_replaceFaviconData.js b/toolkit/components/places/tests/favicons/test_replaceFaviconData.js
new file mode 100644
index 0000000000..2e9835eaa9
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_replaceFaviconData.js
@@ -0,0 +1,395 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests for replaceFaviconData()
+ */
+
+var iconsvc = PlacesUtils.favicons;
+
+var originalFavicon = {
+  file: do_get_file("favicon-normal16.png"),
+  uri: uri(do_get_file("favicon-normal16.png")),
+  data: readFileData(do_get_file("favicon-normal16.png")),
+  mimetype: "image/png",
+};
+
+var uniqueFaviconId = 0;
+function createFavicon(fileName) {
+  let tempdir = Services.dirsvc.get("TmpD", Ci.nsIFile);
+
+  // remove any existing file at the path we're about to copy to
+  let outfile = tempdir.clone();
+  outfile.append(fileName);
+  try {
+    outfile.remove(false);
+  } catch (e) {}
+
+  originalFavicon.file.copyToFollowingLinks(tempdir, fileName);
+
+  let stream = Cc["@mozilla.org/network/file-output-stream;1"].createInstance(
+    Ci.nsIFileOutputStream
+  );
+  stream.init(outfile, 0x02 | 0x08 | 0x10, 0o600, 0);
+
+  // append some data that sniffers/encoders will ignore that will distinguish
+  // the different favicons we'll create
+  uniqueFaviconId++;
+  let uniqueStr = "uid:" + uniqueFaviconId;
+  stream.write(uniqueStr, uniqueStr.length);
+  stream.close();
+
+  Assert.equal(outfile.leafName.substr(0, fileName.length), fileName);
+
+  return {
+    file: outfile,
+    uri: uri(outfile),
+    data: readFileData(outfile),
+    mimetype: "image/png",
+  };
+}
+
+function checkCallbackSucceeded(
+  callbackMimetype,
+  callbackData,
+  sourceMimetype,
+  sourceData
+) {
+  Assert.equal(callbackMimetype, sourceMimetype);
+  Assert.ok(compareArrays(callbackData, sourceData));
+}
+
+function run_test() {
+  // check that the favicon loaded correctly
+  Assert.equal(originalFavicon.data.length, 286);
+  run_next_test();
+}
+
+add_task(async function test_replaceFaviconData_validHistoryURI() {
+  info("test replaceFaviconData for valid history uri");
+
+  let pageURI = uri("http://test1.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let favicon = createFavicon("favicon1.png");
+
+  iconsvc.replaceFaviconData(favicon.uri, favicon.data, favicon.mimetype);
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      favicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconData_validHistoryURI_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        dump("GOT " + aMimeType + "\n");
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          favicon.mimetype,
+          favicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          favicon.mimetype,
+          favicon.data,
+          function test_replaceFaviconData_validHistoryURI_callback() {
+            favicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      systemPrincipal
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_overrideDefaultFavicon() {
+  info("test replaceFaviconData to override a later setAndFetchFaviconForPage");
+
+  let pageURI = uri("http://test2.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let firstFavicon = createFavicon("favicon2.png");
+  let secondFavicon = createFavicon("favicon3.png");
+
+  iconsvc.replaceFaviconData(
+    firstFavicon.uri,
+    secondFavicon.data,
+    secondFavicon.mimetype
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      firstFavicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconData_overrideDefaultFavicon_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          secondFavicon.mimetype,
+          secondFavicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          secondFavicon.mimetype,
+          secondFavicon.data,
+          function test_replaceFaviconData_overrideDefaultFavicon_callback() {
+            firstFavicon.file.remove(false);
+            secondFavicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      systemPrincipal
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_replaceExisting() {
+  info(
+    "test replaceFaviconData to override a previous setAndFetchFaviconForPage"
+  );
+
+  let pageURI = uri("http://test3.bar");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let firstFavicon = createFavicon("favicon4.png");
+  let secondFavicon = createFavicon("favicon5.png");
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      firstFavicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconData_replaceExisting_firstSet_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          firstFavicon.mimetype,
+          firstFavicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          firstFavicon.mimetype,
+          firstFavicon.data,
+          function test_replaceFaviconData_overrideDefaultFavicon_firstCallback() {
+            iconsvc.replaceFaviconData(
+              firstFavicon.uri,
+              secondFavicon.data,
+              secondFavicon.mimetype
+            );
+            PlacesTestUtils.promiseAsyncUpdates().then(() => {
+              checkFaviconDataForPage(
+                pageURI,
+                secondFavicon.mimetype,
+                secondFavicon.data,
+                function test_replaceFaviconData_overrideDefaultFavicon_secondCallback() {
+                  firstFavicon.file.remove(false);
+                  secondFavicon.file.remove(false);
+                  resolve();
+                },
+                systemPrincipal
+              );
+            });
+          }
+        );
+      },
+      systemPrincipal
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_unrelatedReplace() {
+  info("test replaceFaviconData to not make unrelated changes");
+
+  let pageURI = uri("http://test4.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let favicon = createFavicon("favicon6.png");
+  let unrelatedFavicon = createFavicon("favicon7.png");
+
+  iconsvc.replaceFaviconData(
+    unrelatedFavicon.uri,
+    unrelatedFavicon.data,
+    unrelatedFavicon.mimetype
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      favicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconData_unrelatedReplace_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          favicon.mimetype,
+          favicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          favicon.mimetype,
+          favicon.data,
+          function test_replaceFaviconData_unrelatedReplace_callback() {
+            favicon.file.remove(false);
+            unrelatedFavicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      systemPrincipal
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_badInputs() {
+  info("test replaceFaviconData to throw on bad inputs");
+  let icon = createFavicon("favicon8.png");
+
+  Assert.throws(
+    () => iconsvc.replaceFaviconData(icon.uri, icon.data, ""),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => iconsvc.replaceFaviconData(icon.uri, icon.data, "not-an-image"),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => iconsvc.replaceFaviconData(null, icon.data, icon.mimetype),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => iconsvc.replaceFaviconData(icon.uri, [], icon.mimetype),
+    /NS_ERROR_ILLEGAL_VALUE/
+  );
+  Assert.throws(
+    () => iconsvc.replaceFaviconData(icon.uri, null, icon.mimetype),
+    /NS_ERROR_XPC_CANT_CONVERT_PRIMITIVE_TO_ARRAY/
+  );
+
+  icon.file.remove(false);
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_twiceReplace() {
+  info("test replaceFaviconData on multiple replacements");
+
+  let pageURI = uri("http://test5.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let firstFavicon = createFavicon("favicon9.png");
+  let secondFavicon = createFavicon("favicon10.png");
+
+  iconsvc.replaceFaviconData(
+    firstFavicon.uri,
+    firstFavicon.data,
+    firstFavicon.mimetype
+  );
+  iconsvc.replaceFaviconData(
+    firstFavicon.uri,
+    secondFavicon.data,
+    secondFavicon.mimetype
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      firstFavicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconData_twiceReplace_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          secondFavicon.mimetype,
+          secondFavicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          secondFavicon.mimetype,
+          secondFavicon.data,
+          function test_replaceFaviconData_twiceReplace_callback() {
+            firstFavicon.file.remove(false);
+            secondFavicon.file.remove(false);
+            resolve();
+          },
+          systemPrincipal
+        );
+      },
+      systemPrincipal
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconData_rootOverwrite() {
+  info("test replaceFaviconData doesn't overwrite root = 1");
+
+  async function getRootValue(url) {
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(
+      "SELECT root FROM moz_icons WHERE icon_url = :url",
+      { url }
+    );
+    return rows[0].getResultByName("root");
+  }
+
+  const PAGE_URL = "http://rootoverwrite.bar/";
+  let pageURI = Services.io.newURI(PAGE_URL);
+  const ICON_URL = "http://rootoverwrite.bar/favicon.ico";
+  let iconURI = Services.io.newURI(ICON_URL);
+
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let icon = createFavicon("favicon9.png");
+  PlacesUtils.favicons.replaceFaviconData(iconURI, icon.data, icon.mimetype);
+  await PlacesTestUtils.addFavicons(new Map([[PAGE_URL, ICON_URL]]));
+
+  Assert.equal(await getRootValue(ICON_URL), 1, "Check root == 1");
+  let icon2 = createFavicon("favicon10.png");
+  PlacesUtils.favicons.replaceFaviconData(iconURI, icon2.data, icon2.mimetype);
+  // replaceFaviconData doesn't have a callback, but we must wait its updated.
+  await PlacesTestUtils.promiseAsyncUpdates();
+  Assert.equal(await getRootValue(ICON_URL), 1, "Check root did not change");
+
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/favicons/test_replaceFaviconDataFromDataURL.js b/toolkit/components/places/tests/favicons/test_replaceFaviconDataFromDataURL.js
new file mode 100644
index 0000000000..c1b83fc8a7
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_replaceFaviconDataFromDataURL.js
@@ -0,0 +1,537 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests for replaceFaviconData()
+ */
+
+var iconsvc = PlacesUtils.favicons;
+
+var originalFavicon = {
+  file: do_get_file("favicon-normal16.png"),
+  uri: uri(do_get_file("favicon-normal16.png")),
+  data: readFileData(do_get_file("favicon-normal16.png")),
+  mimetype: "image/png",
+};
+
+var uniqueFaviconId = 0;
+function createFavicon(fileName) {
+  let tempdir = Services.dirsvc.get("TmpD", Ci.nsIFile);
+
+  // remove any existing file at the path we're about to copy to
+  let outfile = tempdir.clone();
+  outfile.append(fileName);
+  try {
+    outfile.remove(false);
+  } catch (e) {}
+
+  originalFavicon.file.copyToFollowingLinks(tempdir, fileName);
+
+  let stream = Cc["@mozilla.org/network/file-output-stream;1"].createInstance(
+    Ci.nsIFileOutputStream
+  );
+  stream.init(outfile, 0x02 | 0x08 | 0x10, 0o600, 0);
+
+  // append some data that sniffers/encoders will ignore that will distinguish
+  // the different favicons we'll create
+  uniqueFaviconId++;
+  let uniqueStr = "uid:" + uniqueFaviconId;
+  stream.write(uniqueStr, uniqueStr.length);
+  stream.close();
+
+  Assert.equal(outfile.leafName.substr(0, fileName.length), fileName);
+
+  return {
+    file: outfile,
+    uri: uri(outfile),
+    data: readFileData(outfile),
+    mimetype: "image/png",
+  };
+}
+
+function createDataURLForFavicon(favicon) {
+  return "data:" + favicon.mimetype + ";base64," + toBase64(favicon.data);
+}
+
+function checkCallbackSucceeded(
+  callbackMimetype,
+  callbackData,
+  sourceMimetype,
+  sourceData
+) {
+  Assert.equal(callbackMimetype, sourceMimetype);
+  Assert.ok(compareArrays(callbackData, sourceData));
+}
+
+function run_test() {
+  // check that the favicon loaded correctly
+  Assert.equal(originalFavicon.data.length, 286);
+  run_next_test();
+}
+
+add_task(async function test_replaceFaviconDataFromDataURL_validHistoryURI() {
+  info("test replaceFaviconDataFromDataURL for valid history uri");
+
+  let pageURI = uri("http://test1.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let favicon = createFavicon("favicon1.png");
+  iconsvc.replaceFaviconDataFromDataURL(
+    favicon.uri,
+    createDataURLForFavicon(favicon),
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      favicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconDataFromDataURL_validHistoryURI_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          favicon.mimetype,
+          favicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          favicon.mimetype,
+          favicon.data,
+          function test_replaceFaviconDataFromDataURL_validHistoryURI_callback() {
+            favicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(
+  async function test_replaceFaviconDataFromDataURL_overrideDefaultFavicon() {
+    info(
+      "test replaceFaviconDataFromDataURL to override a later setAndFetchFaviconForPage"
+    );
+
+    let pageURI = uri("http://test2.bar/");
+    await PlacesTestUtils.addVisits(pageURI);
+
+    let firstFavicon = createFavicon("favicon2.png");
+    let secondFavicon = createFavicon("favicon3.png");
+
+    iconsvc.replaceFaviconDataFromDataURL(
+      firstFavicon.uri,
+      createDataURLForFavicon(secondFavicon),
+      0,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+
+    await new Promise(resolve => {
+      iconsvc.setAndFetchFaviconForPage(
+        pageURI,
+        firstFavicon.uri,
+        true,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        function test_replaceFaviconDataFromDataURL_overrideDefaultFavicon_check(
+          aURI,
+          aDataLen,
+          aData,
+          aMimeType
+        ) {
+          checkCallbackSucceeded(
+            aMimeType,
+            aData,
+            secondFavicon.mimetype,
+            secondFavicon.data
+          );
+          checkFaviconDataForPage(
+            pageURI,
+            secondFavicon.mimetype,
+            secondFavicon.data,
+            function test_replaceFaviconDataFromDataURL_overrideDefaultFavicon_callback() {
+              firstFavicon.file.remove(false);
+              secondFavicon.file.remove(false);
+              resolve();
+            }
+          );
+        },
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    });
+
+    await PlacesUtils.history.clear();
+  }
+);
+
+add_task(async function test_replaceFaviconDataFromDataURL_replaceExisting() {
+  info(
+    "test replaceFaviconDataFromDataURL to override a previous setAndFetchFaviconForPage"
+  );
+
+  let pageURI = uri("http://test3.bar");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let firstFavicon = createFavicon("favicon4.png");
+  let secondFavicon = createFavicon("favicon5.png");
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      firstFavicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconDataFromDataURL_replaceExisting_firstSet_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          firstFavicon.mimetype,
+          firstFavicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          firstFavicon.mimetype,
+          firstFavicon.data,
+          function test_replaceFaviconDataFromDataURL_replaceExisting_firstCallback() {
+            iconsvc.replaceFaviconDataFromDataURL(
+              firstFavicon.uri,
+              createDataURLForFavicon(secondFavicon),
+              0,
+              Services.scriptSecurityManager.getSystemPrincipal()
+            );
+            checkFaviconDataForPage(
+              pageURI,
+              secondFavicon.mimetype,
+              secondFavicon.data,
+              function test_replaceFaviconDataFromDataURL_replaceExisting_secondCallback() {
+                firstFavicon.file.remove(false);
+                secondFavicon.file.remove(false);
+                resolve();
+              }
+            );
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconDataFromDataURL_unrelatedReplace() {
+  info("test replaceFaviconDataFromDataURL to not make unrelated changes");
+
+  let pageURI = uri("http://test4.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let favicon = createFavicon("favicon6.png");
+  let unrelatedFavicon = createFavicon("favicon7.png");
+
+  iconsvc.replaceFaviconDataFromDataURL(
+    unrelatedFavicon.uri,
+    createDataURLForFavicon(unrelatedFavicon),
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      favicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconDataFromDataURL_unrelatedReplace_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          favicon.mimetype,
+          favicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          favicon.mimetype,
+          favicon.data,
+          function test_replaceFaviconDataFromDataURL_unrelatedReplace_callback() {
+            favicon.file.remove(false);
+            unrelatedFavicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconDataFromDataURL_badInputs() {
+  info("test replaceFaviconDataFromDataURL to throw on bad inputs");
+
+  let favicon = createFavicon("favicon8.png");
+
+  let ex = null;
+  try {
+    iconsvc.replaceFaviconDataFromDataURL(
+      favicon.uri,
+      "",
+      0,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  } catch (e) {
+    ex = e;
+  } finally {
+    Assert.ok(!!ex);
+  }
+
+  ex = null;
+  try {
+    iconsvc.replaceFaviconDataFromDataURL(
+      null,
+      createDataURLForFavicon(favicon),
+      0,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  } catch (e) {
+    ex = e;
+  } finally {
+    Assert.ok(!!ex);
+  }
+
+  favicon.file.remove(false);
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_replaceFaviconDataFromDataURL_twiceReplace() {
+  info("test replaceFaviconDataFromDataURL on multiple replacements");
+
+  let pageURI = uri("http://test5.bar/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let firstFavicon = createFavicon("favicon9.png");
+  let secondFavicon = createFavicon("favicon10.png");
+
+  iconsvc.replaceFaviconDataFromDataURL(
+    firstFavicon.uri,
+    createDataURLForFavicon(firstFavicon),
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  iconsvc.replaceFaviconDataFromDataURL(
+    firstFavicon.uri,
+    createDataURLForFavicon(secondFavicon),
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await new Promise(resolve => {
+    iconsvc.setAndFetchFaviconForPage(
+      pageURI,
+      firstFavicon.uri,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      function test_replaceFaviconDataFromDataURL_twiceReplace_check(
+        aURI,
+        aDataLen,
+        aData,
+        aMimeType
+      ) {
+        checkCallbackSucceeded(
+          aMimeType,
+          aData,
+          secondFavicon.mimetype,
+          secondFavicon.data
+        );
+        checkFaviconDataForPage(
+          pageURI,
+          secondFavicon.mimetype,
+          secondFavicon.data,
+          function test_replaceFaviconDataFromDataURL_twiceReplace_callback() {
+            firstFavicon.file.remove(false);
+            secondFavicon.file.remove(false);
+            resolve();
+          }
+        );
+      },
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(
+  async function test_replaceFaviconDataFromDataURL_afterRegularAssign() {
+    info("test replaceFaviconDataFromDataURL after replaceFaviconData");
+
+    let pageURI = uri("http://test6.bar/");
+    await PlacesTestUtils.addVisits(pageURI);
+
+    let firstFavicon = createFavicon("favicon11.png");
+    let secondFavicon = createFavicon("favicon12.png");
+
+    iconsvc.replaceFaviconData(
+      firstFavicon.uri,
+      firstFavicon.data,
+      firstFavicon.mimetype
+    );
+    iconsvc.replaceFaviconDataFromDataURL(
+      firstFavicon.uri,
+      createDataURLForFavicon(secondFavicon),
+      0,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+
+    await new Promise(resolve => {
+      iconsvc.setAndFetchFaviconForPage(
+        pageURI,
+        firstFavicon.uri,
+        true,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        function test_replaceFaviconDataFromDataURL_afterRegularAssign_check(
+          aURI,
+          aDataLen,
+          aData,
+          aMimeType
+        ) {
+          checkCallbackSucceeded(
+            aMimeType,
+            aData,
+            secondFavicon.mimetype,
+            secondFavicon.data
+          );
+          checkFaviconDataForPage(
+            pageURI,
+            secondFavicon.mimetype,
+            secondFavicon.data,
+            function test_replaceFaviconDataFromDataURL_afterRegularAssign_callback() {
+              firstFavicon.file.remove(false);
+              secondFavicon.file.remove(false);
+              resolve();
+            }
+          );
+        },
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    });
+
+    await PlacesUtils.history.clear();
+  }
+);
+
+add_task(
+  async function test_replaceFaviconDataFromDataURL_beforeRegularAssign() {
+    info("test replaceFaviconDataFromDataURL before replaceFaviconData");
+
+    let pageURI = uri("http://test7.bar/");
+    await PlacesTestUtils.addVisits(pageURI);
+
+    let firstFavicon = createFavicon("favicon13.png");
+    let secondFavicon = createFavicon("favicon14.png");
+
+    iconsvc.replaceFaviconDataFromDataURL(
+      firstFavicon.uri,
+      createDataURLForFavicon(firstFavicon),
+      0,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+    iconsvc.replaceFaviconData(
+      firstFavicon.uri,
+      secondFavicon.data,
+      secondFavicon.mimetype
+    );
+
+    await new Promise(resolve => {
+      iconsvc.setAndFetchFaviconForPage(
+        pageURI,
+        firstFavicon.uri,
+        true,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        function test_replaceFaviconDataFromDataURL_beforeRegularAssign_check(
+          aURI,
+          aDataLen,
+          aData,
+          aMimeType
+        ) {
+          checkCallbackSucceeded(
+            aMimeType,
+            aData,
+            secondFavicon.mimetype,
+            secondFavicon.data
+          );
+          checkFaviconDataForPage(
+            pageURI,
+            secondFavicon.mimetype,
+            secondFavicon.data,
+            function test_replaceFaviconDataFromDataURL_beforeRegularAssign_callback() {
+              firstFavicon.file.remove(false);
+              secondFavicon.file.remove(false);
+              resolve();
+            }
+          );
+        },
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    });
+
+    await PlacesUtils.history.clear();
+  }
+);
+
+/* toBase64 copied from image/test/unit/test_encoder_png.js */
+
+/* Convert data (an array of integers) to a Base64 string. */
+const toBase64Table =
+  // eslint-disable-next-line no-useless-concat
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" + "0123456789+/";
+const base64Pad = "=";
+function toBase64(data) {
+  let result = "";
+  let length = data.length;
+  let i;
+  // Convert every three bytes to 4 ascii characters.
+  for (i = 0; i < length - 2; i += 3) {
+    result += toBase64Table[data[i] >> 2];
+    result += toBase64Table[((data[i] & 0x03) << 4) + (data[i + 1] >> 4)];
+    result += toBase64Table[((data[i + 1] & 0x0f) << 2) + (data[i + 2] >> 6)];
+    result += toBase64Table[data[i + 2] & 0x3f];
+  }
+
+  // Convert the remaining 1 or 2 bytes, pad out to 4 characters.
+  if (length % 3) {
+    i = length - (length % 3);
+    result += toBase64Table[data[i] >> 2];
+    if (length % 3 == 2) {
+      result += toBase64Table[((data[i] & 0x03) << 4) + (data[i + 1] >> 4)];
+      result += toBase64Table[(data[i + 1] & 0x0f) << 2];
+      result += base64Pad;
+    } else {
+      result += toBase64Table[(data[i] & 0x03) << 4];
+      result += base64Pad + base64Pad;
+    }
+  }
+
+  return result;
+}
diff --git a/toolkit/components/places/tests/favicons/test_root_icons.js b/toolkit/components/places/tests/favicons/test_root_icons.js
new file mode 100644
index 0000000000..f0487cc162
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_root_icons.js
@@ -0,0 +1,246 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests root icons associations and expiration
+ */
+
+add_task(async function () {
+  let pageURI = NetUtil.newURI("http://www.places.test/page/");
+  await PlacesTestUtils.addVisits(pageURI);
+  let faviconURI = NetUtil.newURI("http://www.places.test/favicon.ico");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    faviconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, faviconURI);
+
+  // Sanity checks.
+  Assert.equal(await getFaviconUrlForPage(pageURI), faviconURI.spec);
+  Assert.equal(
+    await getFaviconUrlForPage("https://places.test/somethingelse/"),
+    faviconURI.spec
+  );
+
+  // Check database entries.
+  await PlacesTestUtils.promiseAsyncUpdates();
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute("SELECT * FROM moz_icons");
+  Assert.equal(rows.length, 1, "There should only be 1 icon entry");
+  Assert.equal(
+    rows[0].getResultByName("root"),
+    1,
+    "It should be marked as a root icon"
+  );
+  rows = await db.execute("SELECT * FROM moz_pages_w_icons");
+  Assert.equal(rows.length, 0, "There should be no page entry");
+  rows = await db.execute("SELECT * FROM moz_icons_to_pages");
+  Assert.equal(rows.length, 0, "There should be no relation entry");
+
+  // Add another pages to the same host. The icon should not be removed.
+  await PlacesTestUtils.addVisits("http://places.test/page2/");
+  await PlacesUtils.history.remove(pageURI);
+
+  // Still works since the icon has not been removed.
+  Assert.equal(await getFaviconUrlForPage(pageURI), faviconURI.spec);
+
+  // Remove all the pages for the given domain.
+  await PlacesUtils.history.remove("http://places.test/page2/");
+  // The icon should be removed along with the domain.
+  rows = await db.execute("SELECT * FROM moz_icons");
+  Assert.equal(rows.length, 0, "The icon should have been removed");
+});
+
+add_task(async function test_removePagesByTimeframe() {
+  const BASE_URL = "http://www.places.test";
+  // Add a visit in the past with no directly associated icon.
+  let oldPageURI = NetUtil.newURI(`${BASE_URL}/old/`);
+  await PlacesTestUtils.addVisits({
+    uri: oldPageURI,
+    visitDate: new Date(Date.now() - 86400000),
+  });
+  // And another more recent visit.
+  let pageURI = NetUtil.newURI(`${BASE_URL}/page/`);
+  await PlacesTestUtils.addVisits({
+    uri: pageURI,
+    visitDate: new Date(Date.now() - 7200000),
+  });
+
+  // Add a normal icon to the most recent page.
+  let faviconURI = NetUtil.newURI(`${BASE_URL}/page/favicon.ico`);
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    faviconURI,
+    SMALLSVG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, faviconURI);
+  // Add a root icon to the most recent page.
+  let rootIconURI = NetUtil.newURI(`${BASE_URL}/favicon.ico`);
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    rootIconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, rootIconURI);
+
+  // Sanity checks.
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI),
+    faviconURI.spec,
+    "Should get the biggest icon"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI, 1),
+    rootIconURI.spec,
+    "Should get the smallest icon"
+  );
+  Assert.equal(
+    await getFaviconUrlForPage(oldPageURI),
+    rootIconURI.spec,
+    "Should get the root icon"
+  );
+
+  info("Removing the newer page, not the old one");
+  await PlacesUtils.history.removeByFilter({
+    beginDate: new Date(Date.now() - 14400000),
+    endDate: new Date(),
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute("SELECT * FROM moz_icons");
+  Assert.equal(rows.length, 1, "There should only be 1 icon entry");
+  Assert.equal(
+    rows[0].getResultByName("root"),
+    1,
+    "It should be marked as a root icon"
+  );
+  rows = await db.execute("SELECT * FROM moz_pages_w_icons");
+  Assert.equal(rows.length, 0, "There should be no page entry");
+  rows = await db.execute("SELECT * FROM moz_icons_to_pages");
+  Assert.equal(rows.length, 0, "There should be no relation entry");
+
+  await PlacesUtils.history.removeByFilter({
+    beginDate: new Date(0),
+    endDt: new Date(),
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  rows = await db.execute("SELECT * FROM moz_icons");
+  // Debug logging for possible intermittent failure (bug 1358368).
+  if (rows.length) {
+    dump_table("moz_icons");
+  }
+  Assert.equal(rows.length, 0, "There should be no icon entry");
+});
+
+add_task(async function test_different_host() {
+  let pageURI = NetUtil.newURI("http://places.test/page/");
+  await PlacesTestUtils.addVisits(pageURI);
+  let faviconURI = NetUtil.newURI("http://mozilla.test/favicon.ico");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    faviconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI, faviconURI);
+
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI),
+    faviconURI.spec,
+    "Should get the png icon"
+  );
+  // Check the icon is not marked as a root icon in the database.
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(
+    "SELECT root FROM moz_icons WHERE icon_url = :url",
+    { url: faviconURI.spec }
+  );
+  Assert.strictEqual(rows[0].getResultByName("root"), 0);
+});
+
+add_task(async function test_same_size() {
+  // Add two icons with the same size, one is a root icon. Check that the
+  // non-root icon is preferred when a smaller size is requested.
+  let data = readFileData(do_get_file("favicon-normal32.png"));
+  let pageURI = NetUtil.newURI("http://new_places.test/page/");
+  await PlacesTestUtils.addVisits(pageURI);
+
+  let faviconURI = NetUtil.newURI("http://new_places.test/favicon.ico");
+  PlacesUtils.favicons.replaceFaviconData(faviconURI, data, "image/png");
+  await setFaviconForPage(pageURI, faviconURI);
+  faviconURI = NetUtil.newURI("http://new_places.test/another_icon.ico");
+  PlacesUtils.favicons.replaceFaviconData(faviconURI, data, "image/png");
+  await setFaviconForPage(pageURI, faviconURI);
+
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI, 20),
+    faviconURI.spec,
+    "Should get the non-root icon"
+  );
+});
+
+add_task(async function test_root_on_different_host() {
+  async function getRootValue(url) {
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(
+      "SELECT root FROM moz_icons WHERE icon_url = :url",
+      { url }
+    );
+    return rows[0].getResultByName("root");
+  }
+
+  // Check that a root icon associated to 2 domains is not removed when the
+  // root domain is removed.
+  const TEST_URL1 = "http://places1.test/page/";
+  let pageURI1 = NetUtil.newURI(TEST_URL1);
+  await PlacesTestUtils.addVisits(pageURI1);
+
+  const TEST_URL2 = "http://places2.test/page/";
+  let pageURI2 = NetUtil.newURI(TEST_URL2);
+  await PlacesTestUtils.addVisits(pageURI2);
+
+  // Root favicon for TEST_URL1.
+  const ICON_URL = "http://places1.test/favicon.ico";
+  let iconURI = NetUtil.newURI(ICON_URL);
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    iconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI1, iconURI);
+  Assert.equal(await getRootValue(ICON_URL), 1, "Check root == 1");
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI1, 16),
+    ICON_URL,
+    "The icon should been found"
+  );
+
+  // Same favicon for TEST_URL2.
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    iconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    systemPrincipal
+  );
+  await setFaviconForPage(pageURI2, iconURI);
+  Assert.equal(await getRootValue(ICON_URL), 1, "Check root == 1");
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI2, 16),
+    ICON_URL,
+    "The icon should be found"
+  );
+
+  await PlacesUtils.history.remove(pageURI1);
+
+  Assert.equal(
+    await getFaviconUrlForPage(pageURI2, 16),
+    ICON_URL,
+    "The icon should not have been removed"
+  );
+});
diff --git a/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage.js b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage.js
new file mode 100644
index 0000000000..1b4ea87ec0
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage.js
@@ -0,0 +1,123 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests the normal operation of setAndFetchFaviconForPage.
+
+let gTests = [
+  {
+    desc: "Normal test",
+    href: "http://example.com/normal",
+    loadType: PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    async setup() {
+      await PlacesTestUtils.addVisits({
+        uri: this.href,
+        transition: TRANSITION_TYPED,
+      });
+    },
+  },
+  {
+    desc: "Bookmarked about: uri",
+    href: "about:testAboutURI_bookmarked",
+    loadType: PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    async setup() {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: this.href,
+      });
+    },
+  },
+  {
+    desc: "Bookmarked in private window",
+    href: "http://example.com/privateBrowsing_bookmarked",
+    loadType: PlacesUtils.favicons.FAVICON_LOAD_PRIVATE,
+    async setup() {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: this.href,
+      });
+    },
+  },
+  {
+    desc: "Bookmarked with disabled history",
+    href: "http://example.com/disabledHistory_bookmarked",
+    loadType: PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    async setup() {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: this.href,
+      });
+      Services.prefs.setBoolPref("places.history.enabled", false);
+    },
+    clean() {
+      Services.prefs.setBoolPref("places.history.enabled", true);
+    },
+  },
+];
+
+add_task(async function () {
+  let faviconURI = SMALLPNG_DATA_URI;
+  let faviconMimeType = "image/png";
+
+  registerCleanupFunction(async function () {
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  });
+
+  for (let test of gTests) {
+    info(test.desc);
+    let pageURI = PlacesUtils.toURI(test.href);
+
+    await test.setup();
+
+    let pageGuid;
+    let promise = PlacesTestUtils.waitForNotification(
+      "favicon-changed",
+      events =>
+        events.some(e => {
+          if (e.url == pageURI.spec && e.faviconUrl == faviconURI.spec) {
+            pageGuid = e.pageGuid;
+            return true;
+          }
+          return false;
+        })
+    );
+
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      pageURI,
+      faviconURI,
+      true,
+      test.private,
+      null,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+
+    await promise;
+
+    Assert.equal(
+      pageGuid,
+      await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+        url: pageURI,
+      }),
+      "Page guid is correct"
+    );
+    let { dataLen, data, mimeType } = await PlacesUtils.promiseFaviconData(
+      pageURI.spec
+    );
+    Assert.equal(faviconMimeType, mimeType, "Check expected MimeType");
+    Assert.equal(
+      SMALLPNG_DATA_LEN,
+      data.length,
+      "Check favicon data for the given page matches the provided data"
+    );
+    Assert.equal(
+      dataLen,
+      data.length,
+      "Check favicon dataLen for the given page matches the provided data"
+    );
+
+    if (test.clean) {
+      await test.clean();
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_failures.js b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_failures.js
new file mode 100644
index 0000000000..d5b16bd670
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_failures.js
@@ -0,0 +1,156 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file tests setAndFetchFaviconForPage when it is called with invalid
+ * arguments, and when no favicon is stored for the given arguments.
+ */
+
+let faviconURI = Services.io.newURI(
+  "http://example.org/tests/toolkit/components/places/tests/browser/favicon-normal16.png"
+);
+add_task(async function () {
+  registerCleanupFunction(async function () {
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  });
+
+  // We'll listen for favicon changes for the whole test, to ensure only the
+  // last one will send a notification. Due to thread serialization, at that
+  // point we can be sure previous calls didn't send a notification.
+  let lastPageURI = Services.io.newURI("http://example.com/verification");
+  let promiseIconChanged = PlacesTestUtils.waitForNotification(
+    "favicon-changed",
+    events =>
+      events.some(
+        e => e.url == lastPageURI.spec && e.faviconUrl == SMALLPNG_DATA_URI.spec
+      )
+  );
+
+  info("Test null page uri");
+  Assert.throws(
+    () => {
+      PlacesUtils.favicons.setAndFetchFaviconForPage(
+        null,
+        faviconURI,
+        true,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    },
+    /NS_ERROR_ILLEGAL_VALUE/,
+    "Exception expected because aPageURI is null"
+  );
+
+  info("Test null favicon uri");
+  Assert.throws(
+    () => {
+      PlacesUtils.favicons.setAndFetchFaviconForPage(
+        Services.io.newURI("http://example.com/null_faviconURI"),
+        null,
+        true,
+        PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+        null,
+        Services.scriptSecurityManager.getSystemPrincipal()
+      );
+    },
+    /NS_ERROR_ILLEGAL_VALUE/,
+    "Exception expected because aFaviconURI is null."
+  );
+
+  info("Test about uri");
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    Services.io.newURI("about:testAboutURI"),
+    faviconURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  info("Test private browsing non bookmarked uri");
+  let pageURI = Services.io.newURI("http://example.com/privateBrowsing");
+  await PlacesTestUtils.addVisits({
+    uri: pageURI,
+    transitionType: TRANSITION_TYPED,
+  });
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    pageURI,
+    faviconURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  info("Test disabled history");
+  pageURI = Services.io.newURI("http://example.com/disabledHistory");
+  await PlacesTestUtils.addVisits({
+    uri: pageURI,
+    transition: TRANSITION_TYPED,
+  });
+  Services.prefs.setBoolPref("places.history.enabled", false);
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    pageURI,
+    faviconURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  // The setAndFetchFaviconForPage function calls CanAddURI synchronously, thus
+  // we can set the preference back to true immediately.
+  Services.prefs.setBoolPref("places.history.enabled", true);
+
+  info("Test error icon");
+  // This error icon must stay in sync with FAVICON_ERRORPAGE_URL in
+  // nsIFaviconService.idl and aboutNetError.html.
+  let faviconErrorPageURI = Services.io.newURI(
+    "chrome://global/skin/icons/info.svg"
+  );
+  pageURI = Services.io.newURI("http://example.com/errorIcon");
+  await PlacesTestUtils.addVisits({
+    uri: pageURI,
+    transition: TRANSITION_TYPED,
+  });
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    pageURI,
+    faviconErrorPageURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  info("Test nonexisting page");
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    Services.io.newURI("http://example.com/nonexistingPage"),
+    faviconURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  info("Final sanity check");
+  // This is the only test that should cause the waitForFaviconChanged
+  // callback to be invoked.
+  await PlacesTestUtils.addVisits({
+    uri: lastPageURI,
+    transition: TRANSITION_TYPED,
+  });
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    lastPageURI,
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await promiseIconChanged;
+});
diff --git a/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_redirects.js b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_redirects.js
new file mode 100644
index 0000000000..feda238f97
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_setAndFetchFaviconForPage_redirects.js
@@ -0,0 +1,89 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file tests setAndFetchFaviconForPage on bookmarked redirects.
+
+add_task(async function same_host_redirect() {
+  // Add a bookmarked page that redirects to another page, set a favicon on the
+  // latter and check the former gets it too, if they are in the same host.
+  let srcUrl = "http://bookmarked.com/";
+  let destUrl = "https://other.bookmarked.com/";
+  await PlacesTestUtils.addVisits([
+    { uri: srcUrl, transition: TRANSITION_LINK },
+    {
+      uri: destUrl,
+      transition: TRANSITION_REDIRECT_TEMPORARY,
+      referrer: srcUrl,
+    },
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: srcUrl,
+  });
+
+  registerCleanupFunction(async function () {
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  });
+
+  let promise = PlacesTestUtils.waitForNotification("favicon-changed", events =>
+    events.some(e => e.url == srcUrl && e.faviconUrl == SMALLPNG_DATA_URI.spec)
+  );
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    Services.io.newURI(destUrl),
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await promise;
+
+  // The favicon should be set also on the bookmarked url that redirected.
+  let { dataLen } = await PlacesUtils.promiseFaviconData(srcUrl);
+  Assert.equal(dataLen, SMALLPNG_DATA_LEN, "Check favicon dataLen");
+});
+
+add_task(async function other_host_redirect() {
+  // Add a bookmarked page that redirects to another page, set a favicon on the
+  // latter and check the former gets it too, if they are in the same host.
+  let srcUrl = "http://first.com/";
+  let destUrl = "https://notfirst.com/";
+  await PlacesTestUtils.addVisits([
+    { uri: srcUrl, transition: TRANSITION_LINK },
+    {
+      uri: destUrl,
+      transition: TRANSITION_REDIRECT_TEMPORARY,
+      referrer: srcUrl,
+    },
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: srcUrl,
+  });
+
+  let promise = Promise.race([
+    PlacesTestUtils.waitForNotification("favicon-changed", events =>
+      events.some(
+        e => e.url == srcUrl && e.faviconUrl == SMALLPNG_DATA_URI.spec
+      )
+    ),
+    new Promise((resolve, reject) =>
+      do_timeout(300, () => reject(new Error("timeout")))
+    ),
+  ]);
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    Services.io.newURI(destUrl),
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await Assert.rejects(promise, /timeout/);
+});
diff --git a/toolkit/components/places/tests/favicons/test_svg_favicon.js b/toolkit/components/places/tests/favicons/test_svg_favicon.js
new file mode 100644
index 0000000000..8d9f2edf11
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/test_svg_favicon.js
@@ -0,0 +1,34 @@
+const PAGEURI = NetUtil.newURI("http://deliciousbacon.com/");
+
+add_task(async function () {
+  // First, add a history entry or else Places can't save a favicon.
+  await PlacesTestUtils.addVisits({
+    uri: PAGEURI,
+    transition: TRANSITION_LINK,
+    visitDate: Date.now() * 1000,
+  });
+
+  await new Promise(resolve => {
+    function onSetComplete(aURI, aDataLen, aData, aMimeType, aWidth) {
+      equal(aURI.spec, SMALLSVG_DATA_URI.spec, "setFavicon aURI check");
+      equal(aDataLen, 263, "setFavicon aDataLen check");
+      equal(aMimeType, "image/svg+xml", "setFavicon aMimeType check");
+      dump(aWidth);
+      resolve();
+    }
+
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      PAGEURI,
+      SMALLSVG_DATA_URI,
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      onSetComplete,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  let data = await PlacesUtils.promiseFaviconData(PAGEURI.spec);
+  equal(data.uri.spec, SMALLSVG_DATA_URI.spec, "getFavicon aURI check");
+  equal(data.dataLen, 263, "getFavicon aDataLen check");
+  equal(data.mimeType, "image/svg+xml", "getFavicon aMimeType check");
+});
diff --git a/toolkit/components/places/tests/favicons/xpcshell.toml b/toolkit/components/places/tests/favicons/xpcshell.toml
new file mode 100644
index 0000000000..997aa48e0b
--- /dev/null
+++ b/toolkit/components/places/tests/favicons/xpcshell.toml
@@ -0,0 +1,72 @@
+[DEFAULT]
+head = "head_favicons.js"
+skip-if = ["os == 'android'"]
+support-files = [
+  "expected-favicon-animated16.png.png",
+  "expected-favicon-big32.jpg.png",
+  "expected-favicon-big4.jpg.png",
+  "expected-favicon-big16.ico.png",
+  "expected-favicon-big48.ico.png",
+  "expected-favicon-big64.png.png",
+  "expected-favicon-scale160x3.jpg.png",
+  "expected-favicon-scale3x160.jpg.png",
+  "favicon-animated16.png",
+  "favicon-big16.ico",
+  "favicon-big32.jpg",
+  "favicon-big4.jpg",
+  "favicon-big48.ico",
+  "favicon-big64.png",
+  "favicon-multi.ico",
+  "favicon-multi-frame16.png",
+  "favicon-multi-frame32.png",
+  "favicon-multi-frame64.png",
+  "favicon-normal16.png",
+  "favicon-normal32.png",
+  "favicon-scale160x3.jpg",
+  "favicon-scale3x160.jpg",
+  "noise.png",
+]
+
+["test_cached-favicon_mime_type.js"]
+
+["test_copyFavicons.js"]
+
+["test_expireAllFavicons.js"]
+
+["test_expire_migrated_icons.js"]
+
+["test_expire_on_new_icons.js"]
+
+["test_favicons_conversions.js"]
+
+["test_favicons_protocols_ref.js"]
+
+["test_getFaviconDataForPage.js"]
+
+["test_getFaviconLinkForIcon.js"]
+
+["test_getFaviconURLForPage.js"]
+
+["test_heavy_favicon.js"]
+
+["test_incremental_vacuum.js"]
+
+["test_multiple_frames.js"]
+
+["test_page-icon_protocol.js"]
+
+["test_query_result_favicon_changed_on_child.js"]
+
+["test_replaceFaviconData.js"]
+
+["test_replaceFaviconDataFromDataURL.js"]
+
+["test_root_icons.js"]
+
+["test_setAndFetchFaviconForPage.js"]
+
+["test_setAndFetchFaviconForPage_failures.js"]
+
+["test_setAndFetchFaviconForPage_redirects.js"]
+
+["test_svg_favicon.js"]
diff --git a/toolkit/components/places/tests/gtest/mock_Link.h b/toolkit/components/places/tests/gtest/mock_Link.h
new file mode 100644
index 0000000000..03d9381d52
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/mock_Link.h
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This is a mock Link object which can be used in tests.
+ */
+
+#ifndef mock_Link_h__
+#define mock_Link_h__
+
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/dom/Link.h"
+#include "mozilla/StaticPrefs_layout.h"
+
+class mock_Link : public mozilla::dom::Link {
+ public:
+  NS_DECL_ISUPPORTS
+
+  typedef void (*Handler)(State);
+
+  explicit mock_Link(Handler aHandlerFunction, bool aRunNextTest = true)
+      : mRunNextTest(aRunNextTest) {
+    AwaitNewNotification(aHandlerFunction);
+  }
+
+  void VisitedQueryFinished(bool aVisited) final {
+    // Notify our callback function.
+    mHandler(aVisited ? State::Visited : State::Unvisited);
+
+    // Break the cycle so the object can be destroyed.
+    mDeathGrip = nullptr;
+  }
+
+  size_t SizeOfExcludingThis(mozilla::SizeOfState& aState) const final {
+    return 0;  // the value shouldn't matter
+  }
+
+  void NodeInfoChanged(mozilla::dom::Document* aOldDoc) final {}
+
+  bool GotNotified() const { return !mDeathGrip; }
+
+  void AwaitNewNotification(Handler aNewHandler) {
+    MOZ_ASSERT(!mDeathGrip, "Still waiting for a notification");
+    // Create a cyclic ownership, so that the link will be released only
+    // after its status has been updated.  This will ensure that, when it should
+    // run the next test, it will happen at the end of the test function, if
+    // the link status has already been set before.  Indeed the link status is
+    // updated on a separate connection, thus may happen at any time.
+    mDeathGrip = this;
+    mHandler = aNewHandler;
+  }
+
+ protected:
+  ~mock_Link() {
+    // Run the next test if we are supposed to.
+    if (mRunNextTest) {
+      run_next_test();
+    }
+  }
+
+ private:
+  Handler mHandler = nullptr;
+  bool mRunNextTest;
+  RefPtr<Link> mDeathGrip;
+};
+
+NS_IMPL_ISUPPORTS(mock_Link, mozilla::dom::Link)
+
+#endif  // mock_Link_h__
diff --git a/toolkit/components/places/tests/gtest/moz.build b/toolkit/components/places/tests/gtest/moz.build
new file mode 100644
index 0000000000..eb7157efc5
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/moz.build
@@ -0,0 +1,12 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+UNIFIED_SOURCES += [
+    "test_casing.cpp",
+    "test_IHistory.cpp",
+]
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/toolkit/components/places/tests/gtest/places_test_harness.h b/toolkit/components/places/tests/gtest/places_test_harness.h
new file mode 100644
index 0000000000..f1f1d388cd
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/places_test_harness.h
@@ -0,0 +1,421 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/dom/PlacesEventBinding.h"
+#include "nsIWeakReference.h"
+#include "nsThreadUtils.h"
+#include "nsDocShellCID.h"
+
+#include "nsToolkitCompsCID.h"
+#include "nsServiceManagerUtils.h"
+#include "nsINavHistoryService.h"
+#include "nsIObserverService.h"
+#include "nsIThread.h"
+#include "nsIURI.h"
+#include "mozilla/IHistory.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozIStorageConnection.h"
+#include "mozIStorageStatement.h"
+#include "mozIStorageAsyncStatement.h"
+#include "mozIStorageStatementCallback.h"
+#include "mozIStoragePendingStatement.h"
+#include "nsIObserver.h"
+#include "prinrval.h"
+#include "prtime.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/dom/PlacesEvent.h"
+#include "mozilla/dom/PlacesObservers.h"
+#include "mozilla/places/INativePlacesEventCallback.h"
+
+using mozilla::dom::PlacesEventType;
+using mozilla::dom::PlacesObservers;
+using mozilla::places::INativePlacesEventCallback;
+
+#define WAIT_TIMEOUT_USEC (5 * PR_USEC_PER_SEC)
+
+#define do_check_true(aCondition) EXPECT_TRUE(aCondition)
+
+#define do_check_false(aCondition) EXPECT_FALSE(aCondition)
+
+#define do_check_success(aResult) do_check_true(NS_SUCCEEDED(aResult))
+
+#define do_check_eq(aExpected, aActual) do_check_true((aExpected) == (aActual))
+
+struct Test {
+  void (*func)(void);
+  const char* const name;
+};
+#define PTEST(aName) \
+  { aName, #aName }
+
+/**
+ * Runs the next text.
+ */
+void run_next_test();
+
+/**
+ * To be used around asynchronous work.
+ */
+void do_test_pending();
+void do_test_finished();
+
+/**
+ * Spins current thread until a topic is received.
+ */
+class WaitForTopicSpinner final : public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit WaitForTopicSpinner(const char* const aTopic)
+      : mTopicReceived(false), mStartTime(PR_IntervalNow()) {
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+    do_check_true(observerService);
+    (void)observerService->AddObserver(this, aTopic, false);
+  }
+
+  void Spin() {
+    bool timedOut = false;
+    mozilla::SpinEventLoopUntil(
+        "places:WaitForTopicSpinner::Spin"_ns, [&]() -> bool {
+          if (mTopicReceived) {
+            return true;
+          }
+
+          if ((PR_IntervalNow() - mStartTime) > (WAIT_TIMEOUT_USEC)) {
+            timedOut = true;
+            return true;
+          }
+
+          return false;
+        });
+
+    if (timedOut) {
+      // Timed out waiting for the topic.
+      do_check_true(false);
+    }
+  }
+
+  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) override {
+    mTopicReceived = true;
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+    do_check_true(observerService);
+    (void)observerService->RemoveObserver(this, aTopic);
+    return NS_OK;
+  }
+
+ private:
+  ~WaitForTopicSpinner() = default;
+
+  bool mTopicReceived;
+  PRIntervalTime mStartTime;
+};
+NS_IMPL_ISUPPORTS(WaitForTopicSpinner, nsIObserver)
+
+/**
+ * Spins current thread until a Places notification is received.
+ */
+class WaitForNotificationSpinner final : public INativePlacesEventCallback {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WaitForNotificationSpinner, override)
+
+  explicit WaitForNotificationSpinner(const PlacesEventType aEventType)
+      : mEventType(aEventType), mStartTime(PR_IntervalNow()) {
+    AutoTArray<PlacesEventType, 1> events;
+    events.AppendElement(mEventType);
+    PlacesObservers::AddListener(events, this);
+  }
+
+  void SpinUntilCompleted() {
+    bool timedOut = false;
+    mozilla::SpinEventLoopUntil(
+        "places::WaitForNotificationSpinner::SpinUntilCompleted"_ns,
+        [&]() -> bool {
+          if (mEventReceived) {
+            return true;
+          }
+
+          if ((PR_IntervalNow() - mStartTime) > (WAIT_TIMEOUT_USEC)) {
+            timedOut = true;
+            return true;
+          }
+
+          return false;
+        });
+
+    if (timedOut) {
+      // Timed out waiting for the notification.
+      do_check_true(false);
+    }
+  }
+
+  void HandlePlacesEvent(const PlacesEventSequence& aEvents) override {
+    for (const auto& event : aEvents) {
+      if (event->Type() == mEventType) {
+        mEventReceived = true;
+        AutoTArray<PlacesEventType, 1> events;
+        events.AppendElement(mEventType);
+        PlacesObservers::RemoveListener(events, this);
+        return;
+      }
+    }
+  }
+
+ private:
+  ~WaitForNotificationSpinner() = default;
+
+  bool mEventReceived = false;
+  PlacesEventType mEventType;
+  PRIntervalTime mStartTime;
+};
+
+/**
+ * Spins current thread until an async statement is executed.
+ */
+class PlacesAsyncStatementSpinner final : public mozIStorageStatementCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_MOZISTORAGESTATEMENTCALLBACK
+
+  PlacesAsyncStatementSpinner();
+  void SpinUntilCompleted();
+  uint16_t completionReason;
+
+ protected:
+  ~PlacesAsyncStatementSpinner() = default;
+
+  volatile bool mCompleted;
+};
+
+NS_IMPL_ISUPPORTS(PlacesAsyncStatementSpinner, mozIStorageStatementCallback)
+
+PlacesAsyncStatementSpinner::PlacesAsyncStatementSpinner()
+    : completionReason(0), mCompleted(false) {}
+
+NS_IMETHODIMP
+PlacesAsyncStatementSpinner::HandleResult(mozIStorageResultSet* aResultSet) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlacesAsyncStatementSpinner::HandleError(mozIStorageError* aError) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+PlacesAsyncStatementSpinner::HandleCompletion(uint16_t aReason) {
+  completionReason = aReason;
+  mCompleted = true;
+  return NS_OK;
+}
+
+void PlacesAsyncStatementSpinner::SpinUntilCompleted() {
+  nsCOMPtr<nsIThread> thread(::do_GetCurrentThread());
+  nsresult rv = NS_OK;
+  bool processed = true;
+  while (!mCompleted && NS_SUCCEEDED(rv)) {
+    rv = thread->ProcessNextEvent(true, &processed);
+  }
+}
+
+using PlaceRecord = struct PlaceRecord {
+  int64_t id = -1;
+  int32_t hidden = 0;
+  int32_t typed = 0;
+  int32_t visitCount = 0;
+  nsCString guid;
+  int64_t frecency = -1;
+};
+
+using VisitRecord = struct VisitRecord {
+  int64_t id = -1;
+  int64_t lastVisitId = -1;
+  int32_t transitionType = 0;
+};
+
+already_AddRefed<mozilla::IHistory> do_get_IHistory() {
+  nsCOMPtr<mozilla::IHistory> history = do_GetService(NS_IHISTORY_CONTRACTID);
+  do_check_true(history);
+  return history.forget();
+}
+
+already_AddRefed<nsINavHistoryService> do_get_NavHistory() {
+  nsCOMPtr<nsINavHistoryService> serv =
+      do_GetService(NS_NAVHISTORYSERVICE_CONTRACTID);
+  do_check_true(serv);
+  return serv.forget();
+}
+
+already_AddRefed<mozIStorageConnection> do_get_db() {
+  nsCOMPtr<nsINavHistoryService> history = do_get_NavHistory();
+  do_check_true(history);
+
+  nsCOMPtr<mozIStorageConnection> dbConn;
+  nsresult rv = history->GetDBConnection(getter_AddRefs(dbConn));
+  do_check_success(rv);
+  return dbConn.forget();
+}
+
+/**
+ * Get the place record from the database.
+ *
+ * @param aURI The unique URI of the place we are looking up
+ * @param result Out parameter where the result is stored
+ */
+void do_get_place(nsIURI* aURI, PlaceRecord& result) {
+  nsCOMPtr<mozIStorageConnection> dbConn = do_get_db();
+  nsCOMPtr<mozIStorageStatement> stmt;
+
+  nsCString spec;
+  nsresult rv = aURI->GetSpec(spec);
+  do_check_success(rv);
+
+  rv = dbConn->CreateStatement(
+      nsLiteralCString("SELECT id, hidden, typed, visit_count, guid, frecency "
+                       "FROM moz_places "
+                       "WHERE url_hash = hash(?1) AND url = ?1"),
+      getter_AddRefs(stmt));
+  do_check_success(rv);
+
+  rv = stmt->BindUTF8StringByIndex(0, spec);
+  do_check_success(rv);
+
+  bool hasResults;
+  rv = stmt->ExecuteStep(&hasResults);
+  do_check_success(rv);
+  if (!hasResults) {
+    result.id = 0;
+    return;
+  }
+
+  rv = stmt->GetInt64(0, &result.id);
+  do_check_success(rv);
+  rv = stmt->GetInt32(1, &result.hidden);
+  do_check_success(rv);
+  rv = stmt->GetInt32(2, &result.typed);
+  do_check_success(rv);
+  rv = stmt->GetInt32(3, &result.visitCount);
+  do_check_success(rv);
+  rv = stmt->GetUTF8String(4, result.guid);
+  do_check_success(rv);
+  rv = stmt->GetInt64(5, &result.frecency);
+  do_check_success(rv);
+}
+
+/**
+ * Gets the most recent visit to a place.
+ *
+ * @param placeID ID from the moz_places table
+ * @param result Out parameter where visit is stored
+ */
+void do_get_lastVisit(int64_t placeId, VisitRecord& result) {
+  nsCOMPtr<mozIStorageConnection> dbConn = do_get_db();
+  nsCOMPtr<mozIStorageStatement> stmt;
+
+  nsresult rv = dbConn->CreateStatement(
+      nsLiteralCString(
+          "SELECT id, from_visit, visit_type FROM moz_historyvisits "
+          "WHERE place_id=?1 "
+          "LIMIT 1"),
+      getter_AddRefs(stmt));
+  do_check_success(rv);
+
+  rv = stmt->BindInt64ByIndex(0, placeId);
+  do_check_success(rv);
+
+  bool hasResults;
+  rv = stmt->ExecuteStep(&hasResults);
+  do_check_success(rv);
+
+  if (!hasResults) {
+    result.id = 0;
+    return;
+  }
+
+  rv = stmt->GetInt64(0, &result.id);
+  do_check_success(rv);
+  rv = stmt->GetInt64(1, &result.lastVisitId);
+  do_check_success(rv);
+  rv = stmt->GetInt32(2, &result.transitionType);
+  do_check_success(rv);
+}
+
+void do_wait_async_updates() {
+  nsCOMPtr<mozIStorageConnection> db = do_get_db();
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+
+  db->CreateAsyncStatement("BEGIN EXCLUSIVE"_ns, getter_AddRefs(stmt));
+  nsCOMPtr<mozIStoragePendingStatement> pending;
+  (void)stmt->ExecuteAsync(nullptr, getter_AddRefs(pending));
+
+  db->CreateAsyncStatement("COMMIT"_ns, getter_AddRefs(stmt));
+  RefPtr<PlacesAsyncStatementSpinner> spinner =
+      new PlacesAsyncStatementSpinner();
+  (void)stmt->ExecuteAsync(spinner, getter_AddRefs(pending));
+
+  spinner->SpinUntilCompleted();
+}
+
+/**
+ * Adds a URI to the database.
+ *
+ * @param aURI
+ *        The URI to add to the database.
+ */
+void addURI(nsIURI* aURI) {
+  nsCOMPtr<mozilla::IHistory> history = do_GetService(NS_IHISTORY_CONTRACTID);
+  do_check_true(history);
+  nsresult rv = history->VisitURI(nullptr, aURI, nullptr,
+                                  mozilla::IHistory::TOP_LEVEL, 0);
+  do_check_success(rv);
+
+  do_wait_async_updates();
+}
+
+static const char TOPIC_PROFILE_CHANGE_QM[] = "profile-before-change-qm";
+static const char TOPIC_PLACES_CONNECTION_CLOSED[] = "places-connection-closed";
+
+class WaitForConnectionClosed final : public nsIObserver {
+  RefPtr<WaitForTopicSpinner> mSpinner;
+
+  ~WaitForConnectionClosed() = default;
+
+ public:
+  NS_DECL_ISUPPORTS
+
+  WaitForConnectionClosed() {
+    nsCOMPtr<nsIObserverService> os =
+        do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+    MOZ_ASSERT(os);
+    if (os) {
+      // The places-connection-closed notification happens because of things
+      // that occur during profile-before-change, so we use the stage after that
+      // to wait for it.
+      MOZ_ALWAYS_SUCCEEDS(
+          os->AddObserver(this, TOPIC_PROFILE_CHANGE_QM, false));
+    }
+    mSpinner = new WaitForTopicSpinner(TOPIC_PLACES_CONNECTION_CLOSED);
+  }
+
+  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) override {
+    nsCOMPtr<nsIObserverService> os =
+        do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+    MOZ_ASSERT(os);
+    if (os) {
+      MOZ_ALWAYS_SUCCEEDS(os->RemoveObserver(this, aTopic));
+    }
+
+    mSpinner->Spin();
+
+    return NS_OK;
+  }
+};
+
+NS_IMPL_ISUPPORTS(WaitForConnectionClosed, nsIObserver)
diff --git a/toolkit/components/places/tests/gtest/places_test_harness_tail.h b/toolkit/components/places/tests/gtest/places_test_harness_tail.h
new file mode 100644
index 0000000000..0464d14e0d
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/places_test_harness_tail.h
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWidgetsCID.h"
+#include "nsIUserIdleService.h"
+#include "mozilla/StackWalk.h"
+
+#ifndef TEST_NAME
+#  error "Must #define TEST_NAME before including places_test_harness_tail.h"
+#endif
+
+int gTestsIndex = 0;
+
+#define TEST_INFO_STR "TEST-INFO | "
+
+class RunNextTest : public mozilla::Runnable {
+ public:
+  RunNextTest() : mozilla::Runnable("RunNextTest") {}
+  NS_IMETHOD Run() override {
+    NS_ASSERTION(NS_IsMainThread(), "Not running on the main thread?");
+    if (gTestsIndex < int(mozilla::ArrayLength(gTests))) {
+      do_test_pending();
+      Test& test = gTests[gTestsIndex++];
+      (void)fprintf(stderr, TEST_INFO_STR "Running %s.\n", test.name);
+      test.func();
+    }
+
+    do_test_finished();
+    return NS_OK;
+  }
+};
+
+static const bool kDebugRunNextTest = false;
+
+void run_next_test() {
+  if (kDebugRunNextTest) {
+    printf_stderr("run_next_test()\n");
+    MozWalkTheStack(stderr);
+  }
+  nsCOMPtr<nsIRunnable> event = new RunNextTest();
+  do_check_success(NS_DispatchToCurrentThread(event));
+}
+
+int gPendingTests = 0;
+
+void do_test_pending() {
+  NS_ASSERTION(NS_IsMainThread(), "Not running on the main thread?");
+  if (kDebugRunNextTest) {
+    printf_stderr("do_test_pending()\n");
+    MozWalkTheStack(stderr);
+  }
+  gPendingTests++;
+}
+
+void do_test_finished() {
+  NS_ASSERTION(NS_IsMainThread(), "Not running on the main thread?");
+  NS_ASSERTION(gPendingTests > 0, "Invalid pending test count!");
+  gPendingTests--;
+}
+
+void disable_idle_service() {
+  (void)fprintf(stderr, TEST_INFO_STR "Disabling Idle Service.\n");
+
+  nsCOMPtr<nsIUserIdleService> idle =
+      do_GetService("@mozilla.org/widget/useridleservice;1");
+  idle->SetDisabled(true);
+}
+
+TEST(IHistory, Test)
+{
+  RefPtr<WaitForConnectionClosed> spinClose = new WaitForConnectionClosed();
+
+  // Tinderboxes are constantly on idle.  Since idle tasks can interact with
+  // tests, causing random failures, disable the idle service.
+  disable_idle_service();
+
+  do_test_pending();
+  run_next_test();
+
+  // Spin the event loop until we've run out of tests to run.
+  mozilla::SpinEventLoopUntil("places:TEST(IHistory, Test)"_ns,
+                              [&]() { return !gPendingTests; });
+
+  // And let any other events finish before we quit.
+  (void)NS_ProcessPendingEvents(nullptr);
+}
diff --git a/toolkit/components/places/tests/gtest/test_IHistory.cpp b/toolkit/components/places/tests/gtest/test_IHistory.cpp
new file mode 100644
index 0000000000..a047ca0e63
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/test_IHistory.cpp
@@ -0,0 +1,519 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "places_test_harness.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefService.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "nsNetUtil.h"
+
+#include "mock_Link.h"
+using namespace mozilla;
+using namespace mozilla::dom;
+
+/**
+ * This file tests the IHistory interface.
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// Helper Methods
+
+void expect_visit(Link::State aState) {
+  do_check_true(aState == Link::State::Visited);
+}
+
+void expect_no_visit(Link::State aState) {
+  do_check_true(aState == Link::State::Unvisited);
+}
+
+already_AddRefed<nsIURI> new_test_uri() {
+  // Create a unique spec.
+  static int32_t specNumber = 0;
+  nsCString spec = "http://mozilla.org/"_ns;
+  spec.AppendInt(specNumber++);
+
+  // Create the URI for the spec.
+  nsCOMPtr<nsIURI> testURI;
+  nsresult rv = NS_NewURI(getter_AddRefs(testURI), spec);
+  do_check_success(rv);
+  return testURI.forget();
+}
+
+class VisitURIObserver final : public nsIObserver {
+  ~VisitURIObserver() = default;
+
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit VisitURIObserver(int aExpectedVisits = 1)
+      : mVisits(0), mExpectedVisits(aExpectedVisits) {
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+    do_check_true(observerService);
+    (void)observerService->AddObserver(this, "uri-visit-saved", false);
+  }
+
+  void WaitForNotification() {
+    SpinEventLoopUntil("places:VisitURIObserver::WaitForNotification"_ns,
+                       [&]() { return mVisits >= mExpectedVisits; });
+  }
+
+  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) override {
+    mVisits++;
+
+    if (mVisits == mExpectedVisits) {
+      nsCOMPtr<nsIObserverService> observerService =
+          do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
+      (void)observerService->RemoveObserver(this, "uri-visit-saved");
+    }
+
+    return NS_OK;
+  }
+
+ private:
+  int mVisits;
+  int mExpectedVisits;
+};
+NS_IMPL_ISUPPORTS(VisitURIObserver, nsIObserver)
+
+////////////////////////////////////////////////////////////////////////////////
+//// Test Functions
+
+void test_set_places_enabled() {
+  // Ensure places is enabled for everyone.
+  nsresult rv;
+  nsCOMPtr<nsIPrefBranch> prefBranch =
+      do_GetService(NS_PREFSERVICE_CONTRACTID, &rv);
+  do_check_success(rv);
+
+  rv = prefBranch->SetBoolPref("places.history.enabled", true);
+  do_check_success(rv);
+
+  // Run the next test.
+  run_next_test();
+}
+
+void test_wait_checkpoint() {
+  // This "fake" test is here to wait for the initial WAL checkpoint we force
+  // after creating the database schema, since that may happen at any time,
+  // and cause concurrent readers to access an older checkpoint.
+  nsCOMPtr<mozIStorageConnection> db = do_get_db();
+  nsCOMPtr<mozIStorageAsyncStatement> stmt;
+  db->CreateAsyncStatement("SELECT 1"_ns, getter_AddRefs(stmt));
+  RefPtr<PlacesAsyncStatementSpinner> spinner =
+      new PlacesAsyncStatementSpinner();
+  nsCOMPtr<mozIStoragePendingStatement> pending;
+  (void)stmt->ExecuteAsync(spinner, getter_AddRefs(pending));
+  spinner->SpinUntilCompleted();
+
+  // Run the next test.
+  run_next_test();
+}
+
+// These variables are shared between part 1 and part 2 of the test.  Part 2
+// sets the nsCOMPtr's to nullptr, freeing the reference.
+namespace test_unvisited_does_not_notify {
+nsCOMPtr<nsIURI> testURI;
+RefPtr<mock_Link> testLink;
+}  // namespace test_unvisited_does_not_notify
+void test_unvisited_does_not_notify_part1() {
+  using namespace test_unvisited_does_not_notify;
+
+  // This test is done in two parts.  The first part registers for a URI that
+  // should not be visited.  We then run another test that will also do a
+  // lookup and will be notified.  Since requests are answered in the order they
+  // are requested (at least as long as the same URI isn't asked for later), we
+  // will know that the Link was not notified.
+
+  // First, we need a test URI.
+  testURI = new_test_uri();
+
+  // Create our test Link.
+  testLink = new mock_Link(expect_no_visit);
+
+  // Now, register our Link to be notified.
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  history->RegisterVisitedCallback(testURI, testLink);
+
+  // Run the next test.
+  run_next_test();
+}
+
+void test_visited_notifies() {
+  // First, we add our test URI to history.
+  nsCOMPtr<nsIURI> testURI = new_test_uri();
+  addURI(testURI);
+
+  // Create our test Link.  The callback function will release the reference we
+  // have on the Link.
+  RefPtr<Link> link = new mock_Link(expect_visit);
+
+  // Now, register our Link to be notified.
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  history->RegisterVisitedCallback(testURI, link);
+
+  // Note: test will continue upon notification.
+}
+
+void test_unvisited_does_not_notify_part2() {
+  using namespace test_unvisited_does_not_notify;
+
+  SpinEventLoopUntil("places:test_unvisited_does_not_notify_part2"_ns,
+                     [&]() { return testLink->GotNotified(); });
+
+  // We would have had a failure at this point had the content node been told it
+  // was visited. Therefore, now we change it so that it expects a visited
+  // notification, and unregisters itself after addURI.
+  testLink->AwaitNewNotification(expect_visit);
+  addURI(testURI);
+
+  // Clear the stored variables now.
+  testURI = nullptr;
+  testLink = nullptr;
+}
+
+void test_same_uri_notifies_both() {
+  // First, we add our test URI to history.
+  nsCOMPtr<nsIURI> testURI = new_test_uri();
+  addURI(testURI);
+
+  // Create our two test Links.  The callback function will release the
+  // reference we have on the Links.  Only the second Link should run the next
+  // test!
+  RefPtr<Link> link1 = new mock_Link(expect_visit, false);
+  RefPtr<Link> link2 = new mock_Link(expect_visit);
+
+  // Now, register our Link to be notified.
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  history->RegisterVisitedCallback(testURI, link1);
+  history->RegisterVisitedCallback(testURI, link2);
+
+  // Note: test will continue upon notification.
+}
+
+void test_unregistered_visited_does_not_notify() {
+  // This test must have a test that has a successful notification after it.
+  // The Link would have been notified by now if we were buggy and notified
+  // unregistered Links (due to request serialization).
+
+  nsCOMPtr<nsIURI> testURI = new_test_uri();
+  RefPtr<Link> link = new mock_Link(expect_no_visit, false);
+  nsCOMPtr<IHistory> history(do_get_IHistory());
+  history->RegisterVisitedCallback(testURI, link);
+
+  // Unregister the Link.
+  history->UnregisterVisitedCallback(testURI, link);
+
+  // And finally add a visit for the URI.
+  addURI(testURI);
+
+  // If history tries to notify us, we'll either crash because the Link will
+  // have been deleted (we are the only thing holding a reference to it), or our
+  // expect_no_visit call back will produce a failure.  Either way, the test
+  // will be reported as a failure.
+
+  // Run the next test.
+  run_next_test();
+}
+
+void test_new_visit_notifies_waiting_Link() {
+  // Create our test Link.  The callback function will release the reference we
+  // have on the link.
+  //
+  // Note that this will query the database and we'll get an _unvisited_
+  // notification, then (after we addURI) a _visited_ one.
+  RefPtr<mock_Link> link = new mock_Link(expect_no_visit);
+
+  // Now, register our content node to be notified.
+  nsCOMPtr<nsIURI> testURI = new_test_uri();
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  history->RegisterVisitedCallback(testURI, link);
+
+  SpinEventLoopUntil("places:test_new_visit_notifies_waiting_Link"_ns,
+                     [&]() { return link->GotNotified(); });
+
+  link->AwaitNewNotification(expect_visit);
+
+  // Add ourselves to history.
+  addURI(testURI);
+
+  // Note: test will continue upon notification.
+}
+
+void test_RegisterVisitedCallback_returns_before_notifying() {
+  // Add a URI so that it's already in history.
+  nsCOMPtr<nsIURI> testURI = new_test_uri();
+  addURI(testURI);
+
+  // Create our test Link.
+  RefPtr<Link> link = new mock_Link(expect_no_visit, false);
+
+  // Now, register our content node to be notified.  It should not be notified.
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  history->RegisterVisitedCallback(testURI, link);
+
+  // Remove ourselves as an observer.  We would have failed if we had been
+  // notified.
+  history->UnregisterVisitedCallback(testURI, link);
+
+  run_next_test();
+}
+
+void test_visituri_inserts() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  do_get_place(visitedURI, place);
+
+  do_check_true(place.id > 0);
+  do_check_false(place.hidden);
+  do_check_false(place.typed);
+  do_check_eq(place.visitCount, 1);
+
+  run_next_test();
+}
+
+void test_visituri_updates() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+  RefPtr<VisitURIObserver> finisher;
+
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  do_get_place(visitedURI, place);
+
+  do_check_eq(place.visitCount, 2);
+
+  run_next_test();
+}
+
+void test_visituri_preserves_shown_and_typed() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  // this simulates the uri visit happening in a frame.  Normally frame
+  // transitions would be hidden unless it was previously loaded top-level
+  history->VisitURI(nullptr, visitedURI, lastURI, 0, 0);
+
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver(2);
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  do_get_place(visitedURI, place);
+  do_check_false(place.hidden);
+
+  run_next_test();
+}
+
+void test_visituri_creates_visit() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  VisitRecord visit;
+  do_get_place(visitedURI, place);
+  do_get_lastVisit(place.id, visit);
+
+  do_check_true(visit.id > 0);
+  do_check_eq(visit.lastVisitId, 0);
+  do_check_eq(visit.transitionType, nsINavHistoryService::TRANSITION_LINK);
+
+  run_next_test();
+}
+
+void test_visituri_frecency() {
+  // Adding a visit calculates frecency immediately.
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+  RefPtr<WaitForNotificationSpinner> spinner =
+      new WaitForNotificationSpinner(PlacesEventType::Pages_rank_changed);
+  history->VisitURI(nullptr, visitedURI, nullptr, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+  spinner->SpinUntilCompleted();
+  PlaceRecord place;
+  do_get_place(visitedURI, place);
+  do_check_true(place.frecency > 0);
+  run_next_test();
+}
+
+void test_visituri_hidden() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  {
+    // Insert a framed link visit.
+    nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+    nsCOMPtr<nsINavHistoryService> navHistory = do_get_NavHistory();
+    navHistory->MarkPageAsFollowedLink(visitedURI);
+    history->VisitURI(nullptr, visitedURI, nullptr, 0, 0);
+    RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+    finisher->WaitForNotification();
+    PlaceRecord place;
+    do_get_place(visitedURI, place);
+    do_check_true(place.hidden);
+  }
+
+  // Insert a redirect.
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+  history->VisitURI(nullptr, visitedURI, nullptr,
+                    mozilla::IHistory::TOP_LEVEL | IHistory::REDIRECT_SOURCE,
+                    0);
+  {
+    RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+    finisher->WaitForNotification();
+    PlaceRecord place;
+    do_get_place(visitedURI, place);
+    do_check_true(place.hidden);
+  }
+
+  // Now add a non-hidden visit to the hidden page, check it gets unhidden.
+  history->VisitURI(nullptr, visitedURI, nullptr, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  {
+    RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+    finisher->WaitForNotification();
+    PlaceRecord place;
+    do_get_place(visitedURI, place);
+    do_check_false(place.hidden);
+  }
+
+  // Add another hidden visit, it should stay unhidden.
+  history->VisitURI(nullptr, visitedURI, nullptr,
+                    mozilla::IHistory::TOP_LEVEL | IHistory::REDIRECT_SOURCE,
+                    0);
+  {
+    RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+    finisher->WaitForNotification();
+    PlaceRecord place;
+    do_get_place(visitedURI, place);
+    do_check_false(place.hidden);
+  }
+
+  run_next_test();
+}
+
+void test_visituri_transition_typed() {
+  nsCOMPtr<nsINavHistoryService> navHistory = do_get_NavHistory();
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+
+  navHistory->MarkPageAsTyped(visitedURI);
+  history->VisitURI(nullptr, visitedURI, lastURI, mozilla::IHistory::TOP_LEVEL,
+                    0);
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  VisitRecord visit;
+  do_get_place(visitedURI, place);
+  do_get_lastVisit(place.id, visit);
+
+  do_check_true(visit.transitionType == nsINavHistoryService::TRANSITION_TYPED);
+
+  run_next_test();
+}
+
+void test_visituri_transition_embed() {
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsCOMPtr<nsIURI> lastURI = new_test_uri();
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+
+  history->VisitURI(nullptr, visitedURI, lastURI, 0, 0);
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  PlaceRecord place;
+  VisitRecord visit;
+  do_get_place(visitedURI, place);
+  do_get_lastVisit(place.id, visit);
+
+  do_check_eq(place.id, 0);
+  do_check_eq(visit.id, 0);
+
+  run_next_test();
+}
+
+void test_new_visit_adds_place_guid() {
+  // First, add a visit and wait.  This will also add a place.
+  nsCOMPtr<nsIURI> visitedURI = new_test_uri();
+  nsCOMPtr<IHistory> history = do_get_IHistory();
+  nsresult rv = history->VisitURI(nullptr, visitedURI, nullptr,
+                                  mozilla::IHistory::TOP_LEVEL, 0);
+  do_check_success(rv);
+  RefPtr<VisitURIObserver> finisher = new VisitURIObserver();
+  finisher->WaitForNotification();
+
+  // Check that we have a guid for our visit.
+  PlaceRecord place;
+  do_get_place(visitedURI, place);
+  do_check_eq(place.visitCount, 1);
+  do_check_eq(place.guid.Length(), 12u);
+
+  run_next_test();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//// Test Harness
+
+/**
+ * Note: for tests marked "Order Important!", please see the test for details.
+ */
+Test gTests[] = {
+    PTEST(test_set_places_enabled),               // Must come first!
+    PTEST(test_wait_checkpoint),                  // Must come second!
+    PTEST(test_unvisited_does_not_notify_part1),  // Order Important!
+    PTEST(test_visited_notifies),
+    PTEST(test_unvisited_does_not_notify_part2),  // Order Important!
+    PTEST(test_same_uri_notifies_both),
+    PTEST(test_unregistered_visited_does_not_notify),  // Order Important!
+    PTEST(test_new_visit_adds_place_guid),
+    PTEST(test_new_visit_notifies_waiting_Link),
+    PTEST(test_RegisterVisitedCallback_returns_before_notifying),
+    PTEST(test_visituri_inserts),
+    PTEST(test_visituri_updates),
+    PTEST(test_visituri_preserves_shown_and_typed),
+    PTEST(test_visituri_creates_visit),
+    PTEST(test_visituri_frecency),
+    PTEST(test_visituri_hidden),
+    PTEST(test_visituri_transition_typed),
+    PTEST(test_visituri_transition_embed),
+
+};
+
+#define TEST_NAME "IHistory"
+#include "places_test_harness_tail.h"
diff --git a/toolkit/components/places/tests/gtest/test_casing.cpp b/toolkit/components/places/tests/gtest/test_casing.cpp
new file mode 100644
index 0000000000..079d64bbd0
--- /dev/null
+++ b/toolkit/components/places/tests/gtest/test_casing.cpp
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/intl/UnicodeProperties.h"
+
+// Verify the assertion in SQLFunctions.cpp / nextSearchCandidate that the
+// only non-ASCII characters that lower-case to ASCII ones are:
+//  * U+0130 LATIN CAPITAL LETTER I WITH DOT ABOVE
+//  * U+212A KELVIN SIGN
+TEST(MatchAutocompleteCasing, CaseAssumption)
+{
+  for (uint32_t c = 128; c < 0x110000; c++) {
+    if (c != 304 && c != 8490) {
+      ASSERT_GE(mozilla::intl::UnicodeProperties::ToLower(c), 128U);
+    }
+  }
+}
+
+// Verify the assertion that all ASCII characters lower-case to ASCII.
+TEST(MatchAutocompleteCasing, CaseAssumption2)
+{
+  for (uint32_t c = 0; c < 128; c++) {
+    ASSERT_LT(mozilla::intl::UnicodeProperties::ToLower(c), 128U);
+  }
+}
diff --git a/toolkit/components/places/tests/head_common.js b/toolkit/components/places/tests/head_common.js
new file mode 100644
index 0000000000..d7a465786e
--- /dev/null
+++ b/toolkit/components/places/tests/head_common.js
@@ -0,0 +1,919 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const NS_APP_USER_PROFILE_50_DIR = "ProfD";
+
+// Shortcuts to transitions type.
+const TRANSITION_LINK = Ci.nsINavHistoryService.TRANSITION_LINK;
+const TRANSITION_TYPED = Ci.nsINavHistoryService.TRANSITION_TYPED;
+const TRANSITION_BOOKMARK = Ci.nsINavHistoryService.TRANSITION_BOOKMARK;
+const TRANSITION_EMBED = Ci.nsINavHistoryService.TRANSITION_EMBED;
+const TRANSITION_FRAMED_LINK = Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK;
+const TRANSITION_REDIRECT_PERMANENT =
+  Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT;
+const TRANSITION_REDIRECT_TEMPORARY =
+  Ci.nsINavHistoryService.TRANSITION_REDIRECT_TEMPORARY;
+const TRANSITION_DOWNLOAD = Ci.nsINavHistoryService.TRANSITION_DOWNLOAD;
+const TRANSITION_RELOAD = Ci.nsINavHistoryService.TRANSITION_RELOAD;
+
+const TITLE_LENGTH_MAX = 4096;
+
+var { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+var { PlacesSyncUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesSyncUtils.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  BookmarkHTMLUtils: "resource://gre/modules/BookmarkHTMLUtils.sys.mjs",
+  BookmarkJSONUtils: "resource://gre/modules/BookmarkJSONUtils.sys.mjs",
+  FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
+  NetUtil: "resource://gre/modules/NetUtil.sys.mjs",
+  ObjectUtils: "resource://gre/modules/ObjectUtils.sys.mjs",
+  PlacesBackups: "resource://gre/modules/PlacesBackups.sys.mjs",
+  PlacesDBUtils: "resource://gre/modules/PlacesDBUtils.sys.mjs",
+  PlacesTestUtils: "resource://testing-common/PlacesTestUtils.sys.mjs",
+  PlacesTransactions: "resource://gre/modules/PlacesTransactions.sys.mjs",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.sys.mjs",
+  Sqlite: "resource://gre/modules/Sqlite.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+  TestUtils: "resource://testing-common/TestUtils.sys.mjs",
+});
+
+ChromeUtils.defineLazyGetter(this, "SMALLPNG_DATA_URI", function () {
+  return NetUtil.newURI(
+    "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAA" +
+      "AAAA6fptVAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJggg=="
+  );
+});
+const SMALLPNG_DATA_LEN = 67;
+
+ChromeUtils.defineLazyGetter(this, "SMALLSVG_DATA_URI", function () {
+  return NetUtil.newURI(
+    "data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy5" +
+      "3My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAxMDAgMTAwIiBmaWxs" +
+      "PSIjNDI0ZTVhIj4NCiAgPGNpcmNsZSBjeD0iNTAiIGN5PSI1MCIgcj0iN" +
+      "DQiIHN0cm9rZT0iIzQyNGU1YSIgc3Ryb2tlLXdpZHRoPSIxMSIgZmlsbD" +
+      "0ibm9uZSIvPg0KICA8Y2lyY2xlIGN4PSI1MCIgY3k9IjI0LjYiIHI9IjY" +
+      "uNCIvPg0KICA8cmVjdCB4PSI0NSIgeT0iMzkuOSIgd2lkdGg9IjEwLjEi" +
+      "IGhlaWdodD0iNDEuOCIvPg0KPC9zdmc%2BDQo%3D"
+  );
+});
+
+ChromeUtils.defineLazyGetter(this, "PlacesFrecencyRecalculator", () => {
+  return Cc["@mozilla.org/places/frecency-recalculator;1"].getService(
+    Ci.nsIObserver
+  ).wrappedJSObject;
+});
+
+var gTestDir = do_get_cwd();
+
+// Initialize profile.
+var gProfD = do_get_profile(true);
+
+// Remove any old database.
+clearDB();
+
+/**
+ * Shortcut to create a nsIURI.
+ *
+ * @param aSpec
+ *        URLString of the uri.
+ */
+function uri(aSpec) {
+  return NetUtil.newURI(aSpec);
+}
+
+/**
+ * Gets the database connection.  If the Places connection is invalid it will
+ * try to create a new connection.
+ *
+ * @param [optional] aForceNewConnection
+ *        Forces creation of a new connection to the database.  When a
+ *        connection is asyncClosed it cannot anymore schedule async statements,
+ *        though connectionReady will keep returning true (Bug 726990).
+ *
+ * @return The database connection or null if unable to get one.
+ */
+var gDBConn;
+function DBConn(aForceNewConnection) {
+  if (!aForceNewConnection) {
+    let db = PlacesUtils.history.DBConnection;
+    if (db.connectionReady) {
+      return db;
+    }
+  }
+
+  // If the Places database connection has been closed, create a new connection.
+  if (!gDBConn || aForceNewConnection) {
+    let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+    file.append("places.sqlite");
+    let dbConn = (gDBConn = Services.storage.openDatabase(file));
+
+    // Be sure to cleanly close this connection.
+    promiseTopicObserved("profile-before-change").then(() =>
+      dbConn.asyncClose()
+    );
+  }
+
+  return gDBConn.connectionReady ? gDBConn : null;
+}
+
+/**
+ * Reads data from the provided inputstream.
+ *
+ * @return an array of bytes.
+ */
+function readInputStreamData(aStream) {
+  let bistream = Cc["@mozilla.org/binaryinputstream;1"].createInstance(
+    Ci.nsIBinaryInputStream
+  );
+  try {
+    bistream.setInputStream(aStream);
+    let expectedData = [];
+    let avail;
+    while ((avail = bistream.available())) {
+      expectedData = expectedData.concat(bistream.readByteArray(avail));
+    }
+    return expectedData;
+  } finally {
+    bistream.close();
+  }
+}
+
+/**
+ * Reads the data from the specified nsIFile.
+ *
+ * @param aFile
+ *        The nsIFile to read from.
+ * @return an array of bytes.
+ */
+function readFileData(aFile) {
+  let inputStream = Cc[
+    "@mozilla.org/network/file-input-stream;1"
+  ].createInstance(Ci.nsIFileInputStream);
+  // init the stream as RD_ONLY, -1 == default permissions.
+  inputStream.init(aFile, 0x01, -1, null);
+
+  // Check the returned size versus the expected size.
+  let size = inputStream.available();
+  let bytes = readInputStreamData(inputStream);
+  if (size != bytes.length) {
+    throw new Error("Didn't read expected number of bytes");
+  }
+  return bytes;
+}
+
+/**
+ * Reads the data from the named file, verifying the expected file length.
+ *
+ * @param aFileName
+ *        This file should be located in the same folder as the test.
+ * @param aExpectedLength
+ *        Expected length of the file.
+ *
+ * @return The array of bytes read from the file.
+ */
+function readFileOfLength(aFileName, aExpectedLength) {
+  let data = readFileData(do_get_file(aFileName));
+  Assert.equal(data.length, aExpectedLength);
+  return data;
+}
+
+/**
+ * Returns the base64-encoded version of the given string.  This function is
+ * similar to window.btoa, but is available to xpcshell tests also.
+ *
+ * @param aString
+ *        Each character in this string corresponds to a byte, and must be a
+ *        code point in the range 0-255.
+ *
+ * @return The base64-encoded string.
+ */
+function base64EncodeString(aString) {
+  var stream = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(
+    Ci.nsIStringInputStream
+  );
+  stream.setData(aString, aString.length);
+  var encoder = Cc["@mozilla.org/scriptablebase64encoder;1"].createInstance(
+    Ci.nsIScriptableBase64Encoder
+  );
+  return encoder.encodeToString(stream, aString.length);
+}
+
+/**
+ * Compares two arrays, and returns true if they are equal.
+ *
+ * @param aArray1
+ *        First array to compare.
+ * @param aArray2
+ *        Second array to compare.
+ */
+function compareArrays(aArray1, aArray2) {
+  if (aArray1.length != aArray2.length) {
+    print("compareArrays: array lengths differ\n");
+    return false;
+  }
+
+  for (let i = 0; i < aArray1.length; i++) {
+    if (aArray1[i] != aArray2[i]) {
+      print(
+        "compareArrays: arrays differ at index " +
+          i +
+          ": " +
+          "(" +
+          aArray1[i] +
+          ") != (" +
+          aArray2[i] +
+          ")\n"
+      );
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * Deletes a previously created sqlite file from the profile folder.
+ */
+function clearDB() {
+  try {
+    let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+    file.append("places.sqlite");
+    if (file.exists()) {
+      file.remove(false);
+    }
+  } catch (ex) {
+    dump("Exception: " + ex);
+  }
+}
+
+/**
+ * Dumps the rows of a table out to the console.
+ *
+ * @param aName
+ *        The name of the table or view to output.
+ */
+function dump_table(aName, dbConn) {
+  if (!dbConn) {
+    dbConn = DBConn();
+  }
+  let stmt = dbConn.createStatement("SELECT * FROM " + aName);
+
+  print("\n*** Printing data from " + aName);
+  let count = 0;
+  while (stmt.executeStep()) {
+    let columns = stmt.numEntries;
+
+    if (count == 0) {
+      // Print the column names.
+      for (let i = 0; i < columns; i++) {
+        dump(stmt.getColumnName(i) + "\t");
+      }
+      dump("\n");
+    }
+
+    // Print the rows.
+    for (let i = 0; i < columns; i++) {
+      switch (stmt.getTypeOfIndex(i)) {
+        case Ci.mozIStorageValueArray.VALUE_TYPE_NULL:
+          dump("NULL\t");
+          break;
+        case Ci.mozIStorageValueArray.VALUE_TYPE_INTEGER:
+          dump(stmt.getInt64(i) + "\t");
+          break;
+        case Ci.mozIStorageValueArray.VALUE_TYPE_FLOAT:
+          dump(stmt.getDouble(i) + "\t");
+          break;
+        case Ci.mozIStorageValueArray.VALUE_TYPE_TEXT:
+          dump(stmt.getString(i) + "\t");
+          break;
+      }
+    }
+    dump("\n");
+
+    count++;
+  }
+  print("*** There were a total of " + count + " rows of data.\n");
+
+  stmt.finalize();
+}
+
+/**
+ * Checks if an address is found in the database.
+ * @param aURI
+ *        nsIURI or address to look for.
+ * @return place id of the page or 0 if not found
+ */
+function page_in_database(aURI) {
+  let url = aURI instanceof Ci.nsIURI ? aURI.spec : aURI;
+  let stmt = DBConn().createStatement(
+    "SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url"
+  );
+  stmt.params.url = url;
+  try {
+    if (!stmt.executeStep()) {
+      return 0;
+    }
+    return stmt.getInt64(0);
+  } finally {
+    stmt.finalize();
+  }
+}
+
+/**
+ * Checks how many visits exist for a specified page.
+ * @param aURI
+ *        nsIURI or address to look for.
+ * @return number of visits found.
+ */
+function visits_in_database(aURI) {
+  let url = aURI instanceof Ci.nsIURI ? aURI.spec : aURI;
+  let stmt = DBConn().createStatement(
+    `SELECT count(*) FROM moz_historyvisits v
+     JOIN moz_places h ON h.id = v.place_id
+     WHERE url_hash = hash(:url) AND url = :url`
+  );
+  stmt.params.url = url;
+  try {
+    if (!stmt.executeStep()) {
+      return 0;
+    }
+    return stmt.getInt64(0);
+  } finally {
+    stmt.finalize();
+  }
+}
+
+/**
+ * Allows waiting for an observer notification once.
+ *
+ * @param aTopic
+ *        Notification topic to observe.
+ *
+ * @return {Promise}
+ * @resolves The array [aSubject, aData] from the observed notification.
+ * @rejects Never.
+ */
+function promiseTopicObserved(aTopic) {
+  return new Promise(resolve => {
+    Services.obs.addObserver(function observe(
+      aObsSubject,
+      aObsTopic,
+      aObsData
+    ) {
+      Services.obs.removeObserver(observe, aObsTopic);
+      resolve([aObsSubject, aObsData]);
+    },
+    aTopic);
+  });
+}
+
+/**
+ * Simulates a Places shutdown.
+ */
+var shutdownPlaces = function () {
+  info("shutdownPlaces: starting");
+  let promise = new Promise(resolve => {
+    Services.obs.addObserver(resolve, "places-connection-closed");
+  });
+  let hs = PlacesUtils.history.QueryInterface(Ci.nsIObserver);
+  hs.observe(null, "profile-change-teardown", null);
+  info("shutdownPlaces: sent profile-change-teardown");
+  hs.observe(null, "test-simulate-places-shutdown", null);
+  info("shutdownPlaces: sent test-simulate-places-shutdown");
+  return promise.then(() => {
+    info("shutdownPlaces: complete");
+  });
+};
+
+const FILENAME_BOOKMARKS_HTML = "bookmarks.html";
+const FILENAME_BOOKMARKS_JSON =
+  "bookmarks-" + PlacesBackups.toISODateString(new Date()) + ".json";
+
+/**
+ * Creates a bookmarks.html file in the profile folder from a given source file.
+ *
+ * @param aFilename
+ *        Name of the file to copy to the profile folder.  This file must
+ *        exist in the directory that contains the test files.
+ *
+ * @return nsIFile object for the file.
+ */
+function create_bookmarks_html(aFilename) {
+  if (!aFilename) {
+    do_throw("you must pass a filename to create_bookmarks_html function");
+  }
+  remove_bookmarks_html();
+  let bookmarksHTMLFile = gTestDir.clone();
+  bookmarksHTMLFile.append(aFilename);
+  Assert.ok(bookmarksHTMLFile.exists());
+  bookmarksHTMLFile.copyTo(gProfD, FILENAME_BOOKMARKS_HTML);
+  let profileBookmarksHTMLFile = gProfD.clone();
+  profileBookmarksHTMLFile.append(FILENAME_BOOKMARKS_HTML);
+  Assert.ok(profileBookmarksHTMLFile.exists());
+  return profileBookmarksHTMLFile;
+}
+
+/**
+ * Remove bookmarks.html file from the profile folder.
+ */
+function remove_bookmarks_html() {
+  let profileBookmarksHTMLFile = gProfD.clone();
+  profileBookmarksHTMLFile.append(FILENAME_BOOKMARKS_HTML);
+  if (profileBookmarksHTMLFile.exists()) {
+    profileBookmarksHTMLFile.remove(false);
+    Assert.ok(!profileBookmarksHTMLFile.exists());
+  }
+}
+
+/**
+ * Check bookmarks.html file exists in the profile folder.
+ *
+ * @return nsIFile object for the file.
+ */
+function check_bookmarks_html() {
+  let profileBookmarksHTMLFile = gProfD.clone();
+  profileBookmarksHTMLFile.append(FILENAME_BOOKMARKS_HTML);
+  Assert.ok(profileBookmarksHTMLFile.exists());
+  return profileBookmarksHTMLFile;
+}
+
+/**
+ * Creates a JSON backup in the profile folder folder from a given source file.
+ *
+ * @param aFilename
+ *        Name of the file to copy to the profile folder.  This file must
+ *        exist in the directory that contains the test files.
+ *
+ * @return nsIFile object for the file.
+ */
+function create_JSON_backup(aFilename) {
+  if (!aFilename) {
+    do_throw("you must pass a filename to create_JSON_backup function");
+  }
+  let bookmarksBackupDir = gProfD.clone();
+  bookmarksBackupDir.append("bookmarkbackups");
+  if (!bookmarksBackupDir.exists()) {
+    bookmarksBackupDir.create(Ci.nsIFile.DIRECTORY_TYPE, parseInt("0755", 8));
+    Assert.ok(bookmarksBackupDir.exists());
+  }
+  let profileBookmarksJSONFile = bookmarksBackupDir.clone();
+  profileBookmarksJSONFile.append(FILENAME_BOOKMARKS_JSON);
+  if (profileBookmarksJSONFile.exists()) {
+    profileBookmarksJSONFile.remove();
+  }
+  let bookmarksJSONFile = gTestDir.clone();
+  bookmarksJSONFile.append(aFilename);
+  Assert.ok(bookmarksJSONFile.exists());
+  bookmarksJSONFile.copyTo(bookmarksBackupDir, FILENAME_BOOKMARKS_JSON);
+  profileBookmarksJSONFile = bookmarksBackupDir.clone();
+  profileBookmarksJSONFile.append(FILENAME_BOOKMARKS_JSON);
+  Assert.ok(profileBookmarksJSONFile.exists());
+  return profileBookmarksJSONFile;
+}
+
+/**
+ * Remove bookmarksbackup dir and all backups from the profile folder.
+ */
+function remove_all_JSON_backups() {
+  let bookmarksBackupDir = gProfD.clone();
+  bookmarksBackupDir.append("bookmarkbackups");
+  if (bookmarksBackupDir.exists()) {
+    bookmarksBackupDir.remove(true);
+    Assert.ok(!bookmarksBackupDir.exists());
+  }
+}
+
+/**
+ * Check a JSON backup file for today exists in the profile folder.
+ *
+ * @param aIsAutomaticBackup The boolean indicates whether it's an automatic
+ *        backup.
+ * @return nsIFile object for the file.
+ */
+function check_JSON_backup(aIsAutomaticBackup) {
+  let profileBookmarksJSONFile;
+  if (aIsAutomaticBackup) {
+    let bookmarksBackupDir = gProfD.clone();
+    bookmarksBackupDir.append("bookmarkbackups");
+    let files = bookmarksBackupDir.directoryEntries;
+    while (files.hasMoreElements()) {
+      let entry = files.nextFile;
+      if (PlacesBackups.filenamesRegex.test(entry.leafName)) {
+        profileBookmarksJSONFile = entry;
+        break;
+      }
+    }
+  } else {
+    profileBookmarksJSONFile = gProfD.clone();
+    profileBookmarksJSONFile.append("bookmarkbackups");
+    profileBookmarksJSONFile.append(FILENAME_BOOKMARKS_JSON);
+  }
+  Assert.ok(profileBookmarksJSONFile.exists());
+  return profileBookmarksJSONFile;
+}
+
+/**
+ * Returns the hidden status of a url.
+ *
+ * @param aURI
+ *        The URI or spec to get hidden for.
+ * @return @return true if the url is hidden, false otherwise.
+ */
+function isUrlHidden(aURI) {
+  let url = aURI instanceof Ci.nsIURI ? aURI.spec : aURI;
+  let stmt = DBConn().createStatement(
+    "SELECT hidden FROM moz_places WHERE url_hash = hash(?1) AND url = ?1"
+  );
+  stmt.bindByIndex(0, url);
+  if (!stmt.executeStep()) {
+    throw new Error("No result for hidden.");
+  }
+  let hidden = stmt.getInt32(0);
+  stmt.finalize();
+
+  return !!hidden;
+}
+
+/**
+ * Compares two times in usecs, considering eventual platform timers skews.
+ *
+ * @param aTimeBefore
+ *        The older time in usecs.
+ * @param aTimeAfter
+ *        The newer time in usecs.
+ * @return true if times are ordered, false otherwise.
+ */
+function is_time_ordered(before, after) {
+  // Windows has an estimated 16ms timers precision, since Date.now() and
+  // PR_Now() use different code atm, the results can be unordered by this
+  // amount of time.  See bug 558745 and bug 557406.
+  let isWindows = "@mozilla.org/windows-registry-key;1" in Cc;
+  // Just to be safe we consider 20ms.
+  let skew = isWindows ? 20000000 : 0;
+  return after - before > -skew;
+}
+
+/**
+ * Shutdowns Places, invoking the callback when the connection has been closed.
+ *
+ * @param aCallback
+ *        Function to be called when done.
+ */
+function waitForConnectionClosed(aCallback) {
+  promiseTopicObserved("places-connection-closed").then(aCallback);
+  shutdownPlaces();
+}
+
+/**
+ * Tests if a given guid is valid for use in Places or not.
+ *
+ * @param aGuid
+ *        The guid to test.
+ * @param [optional] aStack
+ *        The stack frame used to report the error.
+ */
+function do_check_valid_places_guid(aGuid) {
+  Assert.ok(/^[a-zA-Z0-9\-_]{12}$/.test(aGuid), "Should be a valid GUID");
+}
+
+/**
+ * Tests that a guid was set in moz_places for a given uri.
+ *
+ * @param aURI
+ *        The uri to check.
+ * @param [optional] aGUID
+ *        The expected guid in the database.
+ */
+async function check_guid_for_uri(aURI, aGUID) {
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: aURI,
+  });
+  if (aGUID) {
+    do_check_valid_places_guid(aGUID);
+    Assert.equal(guid, aGUID, "Should have a guid in moz_places for the URI");
+  }
+}
+
+/**
+ * Tests that a guid was set in moz_places for a given bookmark.
+ *
+ * @param aId
+ *        The bookmark id to check.
+ * @param [optional] aGUID
+ *        The expected guid in the database.
+ */
+async function check_guid_for_bookmark(aId, aGUID) {
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "guid", {
+    id: aId,
+  });
+  if (aGUID) {
+    do_check_valid_places_guid(aGUID);
+    Assert.equal(guid, aGUID, "Should have the correct GUID for the bookmark");
+  }
+}
+
+/**
+ * Compares 2 arrays returning whether they contains the same elements.
+ *
+ * @param a1
+ *        First array to compare.
+ * @param a2
+ *        Second array to compare.
+ * @param [optional] sorted
+ *        Whether the comparison should take in count position of the elements.
+ * @return true if the arrays contain the same elements, false otherwise.
+ */
+function do_compare_arrays(a1, a2, sorted) {
+  if (a1.length != a2.length) {
+    return false;
+  }
+
+  if (sorted) {
+    return a1.every((e, i) => e == a2[i]);
+  }
+  return (
+    !a1.filter(e => !a2.includes(e)).length &&
+    !a2.filter(e => !a1.includes(e)).length
+  );
+}
+
+/**
+ * Generic nsINavHistoryResultObserver that doesn't implement anything, but
+ * provides dummy methods to prevent errors about an object not having a certain
+ * method.
+ */
+function NavHistoryResultObserver() {}
+
+NavHistoryResultObserver.prototype = {
+  batching() {},
+  containerStateChanged() {},
+  invalidateContainer() {},
+  nodeDateAddedChanged() {},
+  nodeHistoryDetailsChanged() {},
+  nodeIconChanged() {},
+  nodeInserted() {},
+  nodeKeywordChanged() {},
+  nodeLastModifiedChanged() {},
+  nodeMoved() {},
+  nodeRemoved() {},
+  nodeTagsChanged() {},
+  nodeTitleChanged() {},
+  nodeURIChanged() {},
+  sortingChanged() {},
+  QueryInterface: ChromeUtils.generateQI(["nsINavHistoryResultObserver"]),
+};
+
+function checkBookmarkObject(info) {
+  do_check_valid_places_guid(info.guid);
+  do_check_valid_places_guid(info.parentGuid);
+  Assert.ok(typeof info.index == "number", "index should be a number");
+  Assert.ok(
+    info.dateAdded.constructor.name == "Date",
+    "dateAdded should be a Date"
+  );
+  Assert.ok(
+    info.lastModified.constructor.name == "Date",
+    "lastModified should be a Date"
+  );
+  Assert.ok(
+    info.lastModified >= info.dateAdded,
+    "lastModified should never be smaller than dateAdded"
+  );
+  Assert.ok(typeof info.type == "number", "type should be a number");
+}
+
+/**
+ * Reads foreign_count value for a given url.
+ */
+async function foreign_count(url) {
+  if (url instanceof Ci.nsIURI) {
+    url = url.spec;
+  }
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.executeCached(
+    `SELECT foreign_count FROM moz_places
+     WHERE url_hash = hash(:url) AND url = :url
+    `,
+    { url }
+  );
+  return !rows.length ? 0 : rows[0].getResultByName("foreign_count");
+}
+
+function compareAscending(a, b) {
+  if (a > b) {
+    return 1;
+  }
+  if (a < b) {
+    return -1;
+  }
+  return 0;
+}
+
+function sortBy(array, prop) {
+  return array.sort((a, b) => compareAscending(a[prop], b[prop]));
+}
+
+/**
+ * Asynchronously set the favicon associated with a page.
+ * @param page
+ *        The page's URL
+ * @param icon
+ *        The URL of the favicon to be set.
+ * @param [optional] forceReload
+ *        Whether to enforce reloading the icon.
+ */
+function setFaviconForPage(page, icon, forceReload = true) {
+  let pageURI =
+    page instanceof Ci.nsIURI ? page : NetUtil.newURI(new URL(page).href);
+  let iconURI =
+    icon instanceof Ci.nsIURI ? icon : NetUtil.newURI(new URL(icon).href);
+  return new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      pageURI,
+      iconURI,
+      forceReload,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      resolve,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+}
+
+function getFaviconUrlForPage(page, width = 0) {
+  let pageURI =
+    page instanceof Ci.nsIURI ? page : NetUtil.newURI(new URL(page).href);
+  return new Promise((resolve, reject) => {
+    PlacesUtils.favicons.getFaviconURLForPage(
+      pageURI,
+      iconURI => {
+        if (iconURI) {
+          resolve(iconURI.spec);
+        } else {
+          reject("Unable to find an icon for " + pageURI.spec);
+        }
+      },
+      width
+    );
+  });
+}
+
+function getFaviconDataForPage(page, width = 0) {
+  let pageURI =
+    page instanceof Ci.nsIURI ? page : NetUtil.newURI(new URL(page).href);
+  return new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      pageURI,
+      (iconUri, len, data, mimeType) => {
+        resolve({ data, mimeType });
+      },
+      width
+    );
+  });
+}
+
+/**
+ * Asynchronously compares contents from 2 favicon urls.
+ */
+async function compareFavicons(icon1, icon2, msg) {
+  icon1 = new URL(icon1 instanceof Ci.nsIURI ? icon1.spec : icon1);
+  icon2 = new URL(icon2 instanceof Ci.nsIURI ? icon2.spec : icon2);
+
+  function getIconData(icon) {
+    return new Promise((resolve, reject) => {
+      NetUtil.asyncFetch(
+        {
+          uri: icon.href,
+          loadUsingSystemPrincipal: true,
+          contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE_FAVICON,
+        },
+        function (inputStream, status) {
+          if (!Components.isSuccessCode(status)) {
+            reject();
+          }
+          let size = inputStream.available();
+          resolve(NetUtil.readInputStreamToString(inputStream, size));
+        }
+      );
+    });
+  }
+
+  let data1 = await getIconData(icon1);
+  Assert.ok(!!data1.length, "Should fetch icon data");
+  let data2 = await getIconData(icon2);
+  Assert.ok(!!data2.length, "Should fetch icon data");
+  Assert.deepEqual(data1, data2, msg);
+}
+
+/**
+ * Get the internal "root" folder name for an item, specified by its itemGuid.
+ * If the itemGuid does not point to a root folder, null is returned.
+ *
+ * @param itemGuid
+ *        the item guid.
+ * @return the internal-root name for the root folder, if itemGuid points
+ * to such folder, null otherwise.
+ */
+function mapItemGuidToInternalRootName(itemGuid) {
+  switch (itemGuid) {
+    case PlacesUtils.bookmarks.rootGuid:
+      return "placesRoot";
+    case PlacesUtils.bookmarks.menuGuid:
+      return "bookmarksMenuFolder";
+    case PlacesUtils.bookmarks.toolbarGuid:
+      return "toolbarFolder";
+    case PlacesUtils.bookmarks.unfiledGuid:
+      return "unfiledBookmarksFolder";
+    case PlacesUtils.bookmarks.mobileGuid:
+      return "mobileFolder";
+  }
+  return null;
+}
+
+const DB_FILENAME = "places.sqlite";
+
+/**
+ * Sets the database to use for the given test.  This should be the very first
+ * thing in the test, otherwise this database will not be used!
+ *
+ * @param {string|string[]} path
+ *        A filename or path to a database. The database must exist.
+ *        If this is a string, then this is assumed to be a filename in the
+ *        directory where the test calling this is located.
+ *        If this is an array, this is assumed to be a path relative to the
+ *        directory that this file, head_common.js, is located.
+ * @param {string} destFileName
+ *        The destination filename to copy the database to.
+ * @return {Promise} the final path to the database
+ */
+async function setupPlacesDatabase(path, destFileName = DB_FILENAME) {
+  let currentDir = do_get_cwd().path;
+
+  if (typeof path == "string") {
+    path = [path];
+  } else {
+    currentDir = PathUtils.parent(currentDir);
+  }
+  let src = PathUtils.join(currentDir, ...path);
+  Assert.ok(await IOUtils.exists(src), "Database file found");
+
+  // Ensure that our database doesn't already exist.
+  let dest = PathUtils.join(PathUtils.profileDir, destFileName);
+  Assert.ok(
+    !(await IOUtils.exists(dest)),
+    "Database file should not exist yet"
+  );
+
+  await IOUtils.copy(src, dest);
+  return dest;
+}
+
+/**
+ * Gets the URLs of pages that have a particular annotation.
+ *
+ * @param {String} name The name of the annotation to search for.
+ * @return An array of URLs found.
+ */
+function getPagesWithAnnotation(name) {
+  return PlacesUtils.promiseDBConnection().then(async db => {
+    let rows = await db.execute(
+      `
+      SELECT h.url FROM moz_anno_attributes n
+      JOIN moz_annos a ON n.id = a.anno_attribute_id
+      JOIN moz_places h ON h.id = a.place_id
+      WHERE n.name = :name
+    `,
+      { name }
+    );
+
+    return rows.map(row => row.getResultByName("url"));
+  });
+}
+
+/**
+ * Checks there are no orphan page annotations in the database, and no
+ * orphan anno attribute names.
+ */
+async function assertNoOrphanPageAnnotations() {
+  let db = await PlacesUtils.promiseDBConnection();
+
+  let rows = await db.execute(`
+    SELECT place_id FROM moz_annos
+    WHERE place_id NOT IN (SELECT id FROM moz_places)
+  `);
+
+  Assert.equal(rows.length, 0, "Should not have any orphan page annotations");
+
+  rows = await db.execute(`
+    SELECT id FROM moz_anno_attributes
+    WHERE id NOT IN (SELECT anno_attribute_id FROM moz_annos) AND
+          id NOT IN (SELECT anno_attribute_id FROM moz_items_annos)`);
+}
diff --git a/toolkit/components/places/tests/history/head_history.js b/toolkit/components/places/tests/history/head_history.js
new file mode 100644
index 0000000000..4adce13cce
--- /dev/null
+++ b/toolkit/components/places/tests/history/head_history.js
@@ -0,0 +1,13 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
diff --git a/toolkit/components/places/tests/history/test_async_history_api.js b/toolkit/components/places/tests/history/test_async_history_api.js
new file mode 100644
index 0000000000..ce0d96b306
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_async_history_api.js
@@ -0,0 +1,1349 @@
+/**
+ * This file tests the async history API exposed by mozIAsyncHistory.
+ */
+
+// Globals
+
+XPCOMUtils.defineLazyServiceGetter(
+  this,
+  "asyncHistory",
+  "@mozilla.org/browser/history;1",
+  "mozIAsyncHistory"
+);
+
+const TEST_DOMAIN = "http://mozilla.org/";
+const URI_VISIT_SAVED = "uri-visit-saved";
+const RECENT_EVENT_THRESHOLD = 15 * 60 * 1000000;
+
+// Helpers
+/**
+ * Object that represents a mozIVisitInfo object.
+ *
+ * @param [optional] aTransitionType
+ *        The transition type of the visit.  Defaults to TRANSITION_LINK if not
+ *        provided.
+ * @param [optional] aVisitTime
+ *        The time of the visit.  Defaults to now if not provided.
+ */
+function VisitInfo(aTransitionType, aVisitTime) {
+  this.transitionType =
+    aTransitionType === undefined ? TRANSITION_LINK : aTransitionType;
+  this.visitDate = aVisitTime || Date.now() * 1000;
+}
+
+function promiseUpdatePlaces(aPlaces, aOptions = {}) {
+  return new Promise((resolve, reject) => {
+    asyncHistory.updatePlaces(
+      aPlaces,
+      Object.assign(
+        {
+          _errors: [],
+          _results: [],
+          handleError(aResultCode, aPlace) {
+            this._errors.push({ resultCode: aResultCode, info: aPlace });
+          },
+          handleResult(aPlace) {
+            this._results.push(aPlace);
+          },
+          handleCompletion(resultCount) {
+            resolve({
+              errors: this._errors,
+              results: this._results,
+              resultCount,
+            });
+          },
+        },
+        aOptions
+      )
+    );
+  });
+}
+
+/**
+ * Listens for a title change notification, and calls aCallback when it gets it.
+ */
+class TitleChangedObserver {
+  /**
+   * Constructor.
+   *
+   * @param aURI
+   *        The URI of the page we expect a notification for.
+   * @param aExpectedTitle
+   *        The expected title of the URI we expect a notification for.
+   * @param aCallback
+   *        The method to call when we have gotten the proper notification about
+   *        the title changing.
+   */
+  constructor(aURI, aExpectedTitle, aCallback) {
+    this.uri = aURI;
+    this.expectedTitle = aExpectedTitle;
+    this.callback = aCallback;
+    this.handlePlacesEvent = this.handlePlacesEvent.bind(this);
+    PlacesObservers.addListener(["page-title-changed"], this.handlePlacesEvent);
+  }
+
+  async handlePlacesEvent(aEvents) {
+    info("'page-title-changed'!!!");
+    Assert.equal(aEvents.length, 1, "Right number of title changed notified");
+    Assert.equal(aEvents[0].type, "page-title-changed");
+    if (this.uri.spec !== aEvents[0].url) {
+      return;
+    }
+    Assert.equal(aEvents[0].title, this.expectedTitle);
+    await check_guid_for_uri(this.uri, aEvents[0].pageGuid);
+    this.callback();
+
+    PlacesObservers.removeListener(
+      ["page-title-changed"],
+      this.handlePlacesEvent
+    );
+  }
+}
+
+/**
+ * Listens for a visit notification, and calls aCallback when it gets it.
+ */
+class VisitObserver {
+  constructor(aURI, aGUID, aCallback) {
+    this.uri = aURI;
+    this.guid = aGUID;
+    this.callback = aCallback;
+    this.handlePlacesEvent = this.handlePlacesEvent.bind(this);
+    PlacesObservers.addListener(["page-visited"], this.handlePlacesEvent);
+  }
+
+  handlePlacesEvent(aEvents) {
+    info("'page-visited'!!!");
+    Assert.equal(aEvents.length, 1, "Right number of visits notified");
+    Assert.equal(aEvents[0].type, "page-visited");
+    let {
+      url,
+      visitId,
+      visitTime,
+      referringVisitId,
+      transitionType,
+      pageGuid,
+      hidden,
+      visitCount,
+      typedCount,
+      lastKnownTitle,
+    } = aEvents[0];
+    let args = [
+      visitId,
+      visitTime,
+      referringVisitId,
+      transitionType,
+      pageGuid,
+      hidden,
+      visitCount,
+      typedCount,
+      lastKnownTitle,
+    ];
+    info("'page-visited' (" + url + args.join(", ") + ")");
+    if (this.uri.spec != url || this.guid != pageGuid) {
+      return;
+    }
+    this.callback(visitTime * 1000, transitionType, lastKnownTitle);
+
+    PlacesObservers.removeListener(["page-visited"], this.handlePlacesEvent);
+  }
+}
+
+/**
+ * Tests that a title was set properly in the database.
+ *
+ * @param aURI
+ *        The uri to check.
+ * @param aTitle
+ *        The expected title in the database.
+ */
+function do_check_title_for_uri(aURI, aTitle) {
+  let stmt = DBConn().createStatement(
+    `SELECT title
+     FROM moz_places
+     WHERE url_hash = hash(:url) AND url = :url`
+  );
+  stmt.params.url = aURI.spec;
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.title, aTitle);
+  stmt.finalize();
+}
+
+// Test Functions
+
+add_task(async function test_interface_exists() {
+  let history = Cc["@mozilla.org/browser/history;1"].getService(Ci.nsISupports);
+  Assert.ok(history instanceof Ci.mozIAsyncHistory);
+});
+
+add_task(async function test_invalid_uri_throws() {
+  // First, test passing in nothing.
+  let place = {
+    visits: [new VisitInfo()],
+  };
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+
+  // Now, test other bogus things.
+  const TEST_VALUES = [
+    null,
+    undefined,
+    {},
+    [],
+    TEST_DOMAIN + "test_invalid_id_throws",
+  ];
+  for (let i = 0; i < TEST_VALUES.length; i++) {
+    place.uri = TEST_VALUES[i];
+    try {
+      await promiseUpdatePlaces(place);
+      do_throw("Should have thrown!");
+    } catch (e) {
+      Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+    }
+  }
+});
+
+add_task(async function test_invalid_places_throws() {
+  // First, test passing in nothing.
+  try {
+    asyncHistory.updatePlaces();
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_XPC_NOT_ENOUGH_ARGS);
+  }
+
+  // Now, test other bogus things.
+  const TEST_VALUES = [null, undefined, {}, [], ""];
+  for (let i = 0; i < TEST_VALUES.length; i++) {
+    let value = TEST_VALUES[i];
+    try {
+      await promiseUpdatePlaces(value);
+      do_throw("Should have thrown!");
+    } catch (e) {
+      Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+    }
+  }
+});
+
+add_task(async function test_invalid_guid_throws() {
+  // First check invalid length guid.
+  let place = {
+    guid: "BAD_GUID",
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_invalid_guid_throws"),
+    visits: [new VisitInfo()],
+  };
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+
+  // Now check invalid character guid.
+  place.guid = "__BADGUID+__";
+  Assert.equal(place.guid.length, 12);
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+});
+
+add_task(async function test_no_visits_throws() {
+  const TEST_URI = NetUtil.newURI(
+    TEST_DOMAIN + "test_no_id_or_guid_no_visits_throws"
+  );
+  const TEST_GUID = "_RANDOMGUID_";
+
+  let log_test_conditions = function (aPlace) {
+    let str =
+      "Testing place with " +
+      (aPlace.uri ? "uri" : "no uri") +
+      ", " +
+      (aPlace.guid ? "guid" : "no guid") +
+      ", " +
+      (aPlace.visits ? "visits array" : "no visits array");
+    info(str);
+  };
+
+  // Loop through every possible case.  Note that we don't actually care about
+  // the case where we have no uri, place id, or guid (covered by another test),
+  // but it is easier to just make sure it too throws than to exclude it.
+  let place = {};
+  for (let uri = 1; uri >= 0; uri--) {
+    place.uri = uri ? TEST_URI : undefined;
+
+    for (let guid = 1; guid >= 0; guid--) {
+      place.guid = guid ? TEST_GUID : undefined;
+
+      for (let visits = 1; visits >= 0; visits--) {
+        place.visits = visits ? [] : undefined;
+
+        log_test_conditions(place);
+        try {
+          await promiseUpdatePlaces(place);
+          do_throw("Should have thrown!");
+        } catch (e) {
+          Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+        }
+      }
+    }
+  }
+});
+
+add_task(async function test_add_visit_no_date_throws() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_add_visit_no_date_throws"),
+    visits: [new VisitInfo()],
+  };
+  delete place.visits[0].visitDate;
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+});
+
+add_task(async function test_add_visit_no_transitionType_throws() {
+  let place = {
+    uri: NetUtil.newURI(
+      TEST_DOMAIN + "test_add_visit_no_transitionType_throws"
+    ),
+    visits: [new VisitInfo()],
+  };
+  delete place.visits[0].transitionType;
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+});
+
+add_task(async function test_add_visit_invalid_transitionType_throws() {
+  // First, test something that has a transition type lower than the first one.
+  let place = {
+    uri: NetUtil.newURI(
+      TEST_DOMAIN + "test_add_visit_invalid_transitionType_throws"
+    ),
+    visits: [new VisitInfo(TRANSITION_LINK - 1)],
+  };
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+
+  // Now, test something that has a transition type greater than the last one.
+  place.visits[0] = new VisitInfo(TRANSITION_RELOAD + 1);
+  try {
+    await promiseUpdatePlaces(place);
+    do_throw("Should have thrown!");
+  } catch (e) {
+    Assert.equal(e.result, Cr.NS_ERROR_INVALID_ARG);
+  }
+});
+
+add_task(async function test_non_addable_uri_errors() {
+  // Array of protocols that nsINavHistoryService::canAddURI returns false for.
+  const URLS = [
+    "about:config",
+    "imap://cyrus.andrew.cmu.edu/archive.imap",
+    "news://new.mozilla.org/mozilla.dev.apps.firefox",
+    "mailbox:Inbox",
+    "cached-favicon:http://mozilla.org/made-up-favicon",
+    "view-source:http://mozilla.org",
+    "chrome://browser/content/browser.xhtml",
+    "resource://gre-resources/hiddenWindow.html",
+    "data:,Hello%2C%20World!",
+    "javascript:alert('hello wolrd!');",
+    "blob:foo",
+    "moz-extension://f49fb5b3-a1e7-cd41-85e1-d61a3950f5e4/index.html",
+  ];
+  let places = [];
+  URLS.forEach(function (url) {
+    try {
+      let place = {
+        uri: NetUtil.newURI(url),
+        title: "test for " + url,
+        visits: [new VisitInfo()],
+      };
+      places.push(place);
+    } catch (e) {
+      if (e.result != Cr.NS_ERROR_FAILURE) {
+        throw e;
+      }
+      // NetUtil.newURI() can throw if e.g. our app knows about imap://
+      // but the account is not set up and so the URL is invalid for us.
+      // Note this in the log but ignore as it's not the subject of this test.
+      info("Could not construct URI for '" + url + "'; ignoring");
+    }
+  });
+
+  let placesResult = await promiseUpdatePlaces(places);
+  if (placesResult.results.length) {
+    do_throw("Unexpected success.");
+  }
+  for (let place of placesResult.errors) {
+    info("Checking '" + place.info.uri.spec + "'");
+    Assert.equal(place.resultCode, Cr.NS_ERROR_INVALID_ARG);
+    Assert.equal(false, await PlacesUtils.history.hasVisits(place.info.uri));
+  }
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_duplicate_guid_errors() {
+  // This test ensures that trying to add a visit, with a guid already found in
+  // another visit, fails.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_first"),
+    visits: [new VisitInfo()],
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(placeInfo.uri));
+
+  let badPlace = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_second"),
+    visits: [new VisitInfo()],
+    guid: placeInfo.guid,
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(badPlace.uri));
+  placesResult = await promiseUpdatePlaces(badPlace);
+  if (placesResult.results.length) {
+    do_throw("Unexpected success.");
+  }
+  let badPlaceInfo = placesResult.errors[0];
+  Assert.equal(badPlaceInfo.resultCode, Cr.NS_ERROR_STORAGE_CONSTRAINT);
+  Assert.equal(
+    false,
+    await PlacesUtils.history.hasVisits(badPlaceInfo.info.uri)
+  );
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_invalid_referrerURI_ignored() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_invalid_referrerURI_ignored"),
+    visits: [new VisitInfo()],
+  };
+  place.visits[0].referrerURI = NetUtil.newURI(
+    place.uri.spec + "_unvisistedURI"
+  );
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  Assert.equal(
+    false,
+    await PlacesUtils.history.hasVisits(place.visits[0].referrerURI)
+  );
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(placeInfo.uri));
+
+  // Check to make sure we do not visit the invalid referrer.
+  Assert.equal(
+    false,
+    await PlacesUtils.history.hasVisits(place.visits[0].referrerURI)
+  );
+
+  // Check to make sure from_visit is zero in database.
+  let stmt = DBConn().createStatement(
+    `SELECT from_visit
+     FROM moz_historyvisits
+     WHERE id = :visit_id`
+  );
+  stmt.params.visit_id = placeInfo.visits[0].visitId;
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.from_visit, 0);
+  stmt.finalize();
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_nonnsIURI_referrerURI_ignored() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_nonnsIURI_referrerURI_ignored"),
+    visits: [new VisitInfo()],
+  };
+  place.visits[0].referrerURI = place.uri.spec + "_nonnsIURI";
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(placeInfo.uri));
+
+  // Check to make sure from_visit is zero in database.
+  let stmt = DBConn().createStatement(
+    `SELECT from_visit
+     FROM moz_historyvisits
+     WHERE id = :visit_id`
+  );
+  stmt.params.visit_id = placeInfo.visits[0].visitId;
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.from_visit, 0);
+  stmt.finalize();
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_old_referrer_ignored() {
+  // This tests that a referrer for a visit which is not recent (specifically,
+  // older than 15 minutes as per RECENT_EVENT_THRESHOLD) is not saved by
+  // updatePlaces.
+  let oldTime = Date.now() * 1000 - (RECENT_EVENT_THRESHOLD + 1);
+  let referrerPlace = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_old_referrer_ignored_referrer"),
+    visits: [new VisitInfo(TRANSITION_LINK, oldTime)],
+  };
+
+  // First we must add our referrer to the history so that it is not ignored
+  // as being invalid.
+  Assert.equal(false, await PlacesUtils.history.hasVisits(referrerPlace.uri));
+  let placesResult = await promiseUpdatePlaces(referrerPlace);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+
+  // Now that the referrer is added, we can add a page with a valid
+  // referrer to determine if the recency of the referrer is taken into
+  // account.
+  Assert.ok(await PlacesUtils.history.hasVisits(referrerPlace.uri));
+
+  let visitInfo = new VisitInfo();
+  visitInfo.referrerURI = referrerPlace.uri;
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_old_referrer_ignored_page"),
+    visits: [visitInfo],
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(place.uri));
+
+  // Though the visit will not contain the referrer, we must examine the
+  // database to be sure.
+  Assert.equal(placeInfo.visits[0].referrerURI, null);
+  let stmt = DBConn().createStatement(
+    `SELECT COUNT(1) AS count
+     FROM moz_historyvisits
+     JOIN moz_places h ON h.id = place_id
+     WHERE url_hash = hash(:page_url) AND url = :page_url
+     AND from_visit = 0`
+  );
+  stmt.params.page_url = place.uri.spec;
+  Assert.ok(stmt.executeStep());
+  Assert.equal(stmt.row.count, 1);
+  stmt.finalize();
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_place_id_ignored() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_place_id_ignored_first"),
+    visits: [new VisitInfo()],
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(place.uri));
+
+  let placeId = placeInfo.placeId;
+  Assert.notEqual(placeId, 0);
+
+  let badPlace = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_place_id_ignored_second"),
+    visits: [new VisitInfo()],
+    placeId,
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(badPlace.uri));
+  placesResult = await promiseUpdatePlaces(badPlace);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  placeInfo = placesResult.results[0];
+
+  Assert.notEqual(placeInfo.placeId, placeId);
+  Assert.ok(await PlacesUtils.history.hasVisits(badPlace.uri));
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_handleCompletion_called_when_complete() {
+  // We test a normal visit, and embeded visit, and a uri that would fail
+  // the canAddURI test to make sure that the notification happens after *all*
+  // of them have had a callback.
+  let places = [
+    {
+      uri: NetUtil.newURI(
+        TEST_DOMAIN + "test_handleCompletion_called_when_complete"
+      ),
+      visits: [new VisitInfo(), new VisitInfo(TRANSITION_EMBED)],
+    },
+    {
+      uri: NetUtil.newURI("data:,Hello%2C%20World!"),
+      visits: [new VisitInfo()],
+    },
+  ];
+  Assert.equal(false, await PlacesUtils.history.hasVisits(places[0].uri));
+  Assert.equal(false, await PlacesUtils.history.hasVisits(places[1].uri));
+
+  const EXPECTED_COUNT_SUCCESS = 2;
+  const EXPECTED_COUNT_FAILURE = 1;
+
+  let { results, errors } = await promiseUpdatePlaces(places);
+
+  Assert.equal(results.length, EXPECTED_COUNT_SUCCESS);
+  Assert.equal(errors.length, EXPECTED_COUNT_FAILURE);
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_add_visit() {
+  const VISIT_TIME = Date.now() * 1000;
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_add_visit"),
+    title: "test_add_visit title",
+    visits: [],
+  };
+  for (let t in PlacesUtils.history.TRANSITIONS) {
+    if (t == "EMBED") {
+      continue;
+    }
+    let transitionType = PlacesUtils.history.TRANSITIONS[t];
+    place.visits.push(new VisitInfo(transitionType, VISIT_TIME));
+  }
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let callbackCount = 0;
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  for (let placeInfo of placesResult.results) {
+    Assert.ok(await PlacesUtils.history.hasVisits(place.uri));
+
+    // Check mozIPlaceInfo properties.
+    Assert.ok(place.uri.equals(placeInfo.uri));
+    Assert.equal(placeInfo.frecency, -1); // We don't pass frecency here!
+    Assert.equal(placeInfo.title, place.title);
+
+    // Check mozIVisitInfo properties.
+    let visits = placeInfo.visits;
+    Assert.equal(visits.length, 1);
+    let visit = visits[0];
+    Assert.equal(visit.visitDate, VISIT_TIME);
+    Assert.ok(
+      Object.values(PlacesUtils.history.TRANSITIONS).includes(
+        visit.transitionType
+      )
+    );
+    Assert.ok(visit.referrerURI === null);
+
+    // For TRANSITION_EMBED visits, many properties will always be zero or
+    // undefined.
+    if (visit.transitionType == TRANSITION_EMBED) {
+      // Check mozIPlaceInfo properties.
+      Assert.equal(placeInfo.placeId, 0, "//");
+      Assert.equal(placeInfo.guid, null);
+
+      // Check mozIVisitInfo properties.
+      Assert.equal(visit.visitId, 0);
+    } else {
+      // But they should be valid for non-embed visits.
+      // Check mozIPlaceInfo properties.
+      Assert.ok(placeInfo.placeId > 0);
+      do_check_valid_places_guid(placeInfo.guid);
+
+      // Check mozIVisitInfo properties.
+      Assert.ok(visit.visitId > 0);
+    }
+
+    // If we have had all of our callbacks, continue running tests.
+    if (++callbackCount == place.visits.length) {
+      await PlacesTestUtils.promiseAsyncUpdates();
+    }
+  }
+});
+
+add_task(async function test_properties_saved() {
+  // Check each transition type to make sure it is saved properly.
+  let places = [];
+  for (let t in PlacesUtils.history.TRANSITIONS) {
+    if (t == "EMBED") {
+      continue;
+    }
+    let transitionType = PlacesUtils.history.TRANSITIONS[t];
+    let place = {
+      uri: NetUtil.newURI(
+        TEST_DOMAIN + "test_properties_saved/" + transitionType
+      ),
+      title: "test_properties_saved test",
+      visits: [new VisitInfo(transitionType)],
+    };
+    Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+    places.push(place);
+  }
+
+  let callbackCount = 0;
+  let placesResult = await promiseUpdatePlaces(places);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  for (let placeInfo of placesResult.results) {
+    let uri = placeInfo.uri;
+    Assert.ok(await PlacesUtils.history.hasVisits(uri));
+    let visit = placeInfo.visits[0];
+    print(
+      "TEST-INFO | test_properties_saved | updatePlaces callback for " +
+        "transition type " +
+        visit.transitionType
+    );
+
+    // Note that TRANSITION_EMBED should not be in the database.
+    const EXPECTED_COUNT = visit.transitionType == TRANSITION_EMBED ? 0 : 1;
+
+    // mozIVisitInfo::date
+    let stmt = DBConn().createStatement(
+      `SELECT COUNT(1) AS count
+       FROM moz_places h
+       JOIN moz_historyvisits v
+       ON h.id = v.place_id
+       WHERE h.url_hash = hash(:page_url) AND h.url = :page_url
+       AND v.visit_date = :visit_date`
+    );
+    stmt.params.page_url = uri.spec;
+    stmt.params.visit_date = visit.visitDate;
+    Assert.ok(stmt.executeStep());
+    Assert.equal(stmt.row.count, EXPECTED_COUNT);
+    stmt.finalize();
+
+    // mozIVisitInfo::transitionType
+    stmt = DBConn().createStatement(
+      `SELECT COUNT(1) AS count
+       FROM moz_places h
+       JOIN moz_historyvisits v
+       ON h.id = v.place_id
+       WHERE h.url_hash = hash(:page_url) AND h.url = :page_url
+       AND v.visit_type = :transition_type`
+    );
+    stmt.params.page_url = uri.spec;
+    stmt.params.transition_type = visit.transitionType;
+    Assert.ok(stmt.executeStep());
+    Assert.equal(stmt.row.count, EXPECTED_COUNT);
+    stmt.finalize();
+
+    // mozIPlaceInfo::title
+    stmt = DBConn().createStatement(
+      `SELECT COUNT(1) AS count
+       FROM moz_places h
+       WHERE h.url_hash = hash(:page_url) AND h.url = :page_url
+       AND h.title = :title`
+    );
+    stmt.params.page_url = uri.spec;
+    stmt.params.title = placeInfo.title;
+    Assert.ok(stmt.executeStep());
+    Assert.equal(stmt.row.count, EXPECTED_COUNT);
+    stmt.finalize();
+
+    // If we have had all of our callbacks, continue running tests.
+    if (++callbackCount == places.length) {
+      await PlacesTestUtils.promiseAsyncUpdates();
+    }
+  }
+});
+
+add_task(async function test_guid_saved() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_guid_saved"),
+    guid: "__TESTGUID__",
+    visits: [new VisitInfo()],
+  };
+  do_check_valid_places_guid(place.guid);
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  let uri = placeInfo.uri;
+  Assert.ok(await PlacesUtils.history.hasVisits(uri));
+  Assert.equal(placeInfo.guid, place.guid);
+  await check_guid_for_uri(uri, place.guid);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_referrer_saved() {
+  let places = [
+    {
+      uri: NetUtil.newURI(TEST_DOMAIN + "test_referrer_saved/referrer"),
+      visits: [new VisitInfo()],
+    },
+    {
+      uri: NetUtil.newURI(TEST_DOMAIN + "test_referrer_saved/test"),
+      visits: [new VisitInfo()],
+    },
+  ];
+  places[1].visits[0].referrerURI = places[0].uri;
+  Assert.equal(false, await PlacesUtils.history.hasVisits(places[0].uri));
+  Assert.equal(false, await PlacesUtils.history.hasVisits(places[1].uri));
+
+  let resultCount = 0;
+  let placesResult = await promiseUpdatePlaces(places);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  for (let placeInfo of placesResult.results) {
+    let uri = placeInfo.uri;
+    Assert.ok(await PlacesUtils.history.hasVisits(uri));
+    let visit = placeInfo.visits[0];
+
+    // We need to insert all of our visits before we can test conditions.
+    if (++resultCount == places.length) {
+      Assert.ok(places[0].uri.equals(visit.referrerURI));
+
+      let stmt = DBConn().createStatement(
+        `SELECT COUNT(1) AS count
+         FROM moz_historyvisits
+         JOIN moz_places h ON h.id = place_id
+         WHERE url_hash = hash(:page_url) AND url = :page_url
+         AND from_visit = (
+           SELECT v.id
+           FROM moz_historyvisits v
+           JOIN moz_places h ON h.id = place_id
+           WHERE url_hash = hash(:referrer) AND url = :referrer
+         )`
+      );
+      stmt.params.page_url = uri.spec;
+      stmt.params.referrer = visit.referrerURI.spec;
+      Assert.ok(stmt.executeStep());
+      Assert.equal(stmt.row.count, 1);
+      stmt.finalize();
+
+      await PlacesTestUtils.promiseAsyncUpdates();
+    }
+  }
+});
+
+add_task(async function test_guid_change_saved() {
+  // First, add a visit for it.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_guid_change_saved"),
+    visits: [new VisitInfo()],
+  };
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  // Then, change the guid with visits.
+  place.guid = "_GUIDCHANGE_";
+  place.visits = [new VisitInfo()];
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  await check_guid_for_uri(place.uri, place.guid);
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_title_change_saved() {
+  // First, add a visit for it.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_title_change_saved"),
+    title: "original title",
+    visits: [new VisitInfo()],
+  };
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+
+  // Now, make sure the empty string clears the title.
+  place.title = "";
+  place.visits = [new VisitInfo()];
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  do_check_title_for_uri(place.uri, null);
+
+  // Then, change the title with visits.
+  place.title = "title change";
+  place.visits = [new VisitInfo()];
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  do_check_title_for_uri(place.uri, place.title);
+
+  // Lastly, check that the title is cleared if we set it to null.
+  place.title = null;
+  place.visits = [new VisitInfo()];
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  do_check_title_for_uri(place.uri, place.title);
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_no_title_does_not_clear_title() {
+  const TITLE = "test title";
+  // First, add a visit for it.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_no_title_does_not_clear_title"),
+    title: TITLE,
+    visits: [new VisitInfo()],
+  };
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  // Now, make sure that not specifying a title does not clear it.
+  delete place.title;
+  place.visits = [new VisitInfo()];
+  placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  do_check_title_for_uri(place.uri, TITLE);
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_title_change_notifies() {
+  // There are three cases to test.  The first case is to make sure we do not
+  // get notified if we do not specify a title.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_title_change_notifies"),
+    visits: [new VisitInfo()],
+  };
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  new TitleChangedObserver(place.uri, "DO NOT WANT", function () {
+    do_throw("unexpected callback!");
+  });
+
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+
+  // The second case to test is that we don't get the notification when we add
+  // it for the first time.  The first case will fail before our callback if it
+  // is busted, so we can do this now.
+  place.uri = NetUtil.newURI(place.uri.spec + "/new-visit-with-title");
+  place.title = "title 1";
+  let expectedNotification = false;
+  let titleChangeObserver;
+  let titleChangePromise = new Promise((resolve, reject) => {
+    titleChangeObserver = new TitleChangedObserver(
+      place.uri,
+      place.title,
+      function () {
+        Assert.ok(
+          expectedNotification,
+          "Should not get notified for " +
+            place.uri.spec +
+            " with title " +
+            place.title
+        );
+        if (expectedNotification) {
+          resolve();
+        }
+      }
+    );
+  });
+
+  let visitPromise = new Promise(resolve => {
+    function onVisits(events) {
+      Assert.equal(events.length, 1, "Should only get notified for one visit.");
+      Assert.equal(events[0].type, "page-visited");
+      let { url } = events[0];
+      Assert.equal(
+        url,
+        place.uri.spec,
+        "Should get notified for visiting the new URI."
+      );
+      PlacesObservers.removeListener(["page-visited"], onVisits);
+      resolve();
+    }
+    PlacesObservers.addListener(["page-visited"], onVisits);
+  });
+  asyncHistory.updatePlaces(place);
+  await visitPromise;
+
+  // The third case to test is to make sure we get a notification when
+  // we change an existing place.
+  expectedNotification = true;
+  titleChangeObserver.expectedTitle = place.title = "title 2";
+  place.visits = [new VisitInfo()];
+  asyncHistory.updatePlaces(place);
+
+  await titleChangePromise;
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_visit_notifies() {
+  // There are two observers we need to see for each visit. One is an
+  // PlacesObservers and the other is the uri-visit-saved observer topic.
+  let place = {
+    guid: "abcdefghijkl",
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_visit_notifies"),
+    visits: [new VisitInfo()],
+  };
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+
+  function promiseVisitObserver(aPlace) {
+    return new Promise((resolve, reject) => {
+      let callbackCount = 0;
+      let finisher = function () {
+        if (++callbackCount == 2) {
+          resolve();
+        }
+      };
+      new VisitObserver(place.uri, place.guid, function (
+        aVisitDate,
+        aTransitionType
+      ) {
+        let visit = place.visits[0];
+        Assert.equal(visit.visitDate, aVisitDate);
+        Assert.equal(visit.transitionType, aTransitionType);
+
+        finisher();
+      });
+      let observer = function (aSubject, aTopic, aData) {
+        info("observe(" + aSubject + ", " + aTopic + ", " + aData + ")");
+        Assert.ok(aSubject instanceof Ci.nsIURI);
+        Assert.ok(aSubject.equals(place.uri));
+
+        Services.obs.removeObserver(observer, URI_VISIT_SAVED);
+        finisher();
+      };
+      Services.obs.addObserver(observer, URI_VISIT_SAVED);
+      asyncHistory.updatePlaces(place);
+    });
+  }
+
+  await promiseVisitObserver(place);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+// test with empty mozIVisitInfoCallback object
+add_task(async function test_callbacks_not_supplied() {
+  const URLS = [
+    "imap://cyrus.andrew.cmu.edu/archive.imap", // bad URI
+    "http://mozilla.org/", // valid URI
+  ];
+  let places = [];
+  URLS.forEach(function (url) {
+    try {
+      let place = {
+        uri: NetUtil.newURI(url),
+        title: "test for " + url,
+        visits: [new VisitInfo()],
+      };
+      places.push(place);
+    } catch (e) {
+      if (e.result != Cr.NS_ERROR_FAILURE) {
+        throw e;
+      }
+      // NetUtil.newURI() can throw if e.g. our app knows about imap://
+      // but the account is not set up and so the URL is invalid for us.
+      // Note this in the log but ignore as it's not the subject of this test.
+      info("Could not construct URI for '" + url + "'; ignoring");
+    }
+  });
+
+  asyncHistory.updatePlaces(places, {});
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+// Test that we don't wrongly overwrite typed and hidden when adding new visits.
+add_task(async function test_typed_hidden_not_overwritten() {
+  await PlacesUtils.history.clear();
+  let places = [
+    {
+      uri: NetUtil.newURI("http://mozilla.org/"),
+      title: "test",
+      visits: [new VisitInfo(TRANSITION_TYPED), new VisitInfo(TRANSITION_LINK)],
+    },
+    {
+      uri: NetUtil.newURI("http://mozilla.org/"),
+      title: "test",
+      visits: [new VisitInfo(TRANSITION_FRAMED_LINK)],
+    },
+  ];
+  await promiseUpdatePlaces(places);
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(
+    "SELECT hidden, typed FROM moz_places WHERE url_hash = hash(:url) AND url = :url",
+    { url: "http://mozilla.org/" }
+  );
+  Assert.equal(
+    rows[0].getResultByName("typed"),
+    1,
+    "The page should be marked as typed"
+  );
+  Assert.equal(
+    rows[0].getResultByName("hidden"),
+    0,
+    "The page should be marked as not hidden"
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_omit_frecency_notifications() {
+  // When multiple entries are inserted, frecency is calculated delayed, so
+  // we won't get a ranking changed notification until recalculation happens.
+  await PlacesUtils.history.clear();
+  let notified = false;
+  let listener = events => {
+    notified = true;
+    PlacesUtils.observers.removeListener(["pages-rank-changed"], listener);
+  };
+  PlacesUtils.observers.addListener(["pages-rank-changed"], listener);
+  let places = [
+    {
+      uri: NetUtil.newURI("http://mozilla.org/"),
+      title: "test",
+      visits: [new VisitInfo(TRANSITION_TYPED)],
+    },
+    {
+      uri: NetUtil.newURI("http://example.org/"),
+      title: "test",
+      visits: [new VisitInfo(TRANSITION_TYPED)],
+    },
+  ];
+  await promiseUpdatePlaces(places);
+  Assert.ok(!notified);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.ok(notified);
+});
+
+add_task(async function test_ignore_errors() {
+  await PlacesUtils.history.clear();
+  // This test ensures that trying to add a visit, with a guid already found in
+  // another visit, fails - but doesn't report if we told it not to.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_first"),
+    visits: [new VisitInfo()],
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(placeInfo.uri));
+
+  let badPlace = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_second"),
+    visits: [new VisitInfo()],
+    guid: placeInfo.guid,
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(badPlace.uri));
+  placesResult = await promiseUpdatePlaces(badPlace, { ignoreErrors: true });
+  if (placesResult.results.length) {
+    do_throw("Unexpected success.");
+  }
+  Assert.equal(
+    placesResult.errors.length,
+    0,
+    "Should have seen 0 errors because we disabled reporting."
+  );
+  Assert.equal(
+    placesResult.results.length,
+    0,
+    "Should have seen 0 results because there were none."
+  );
+  Assert.equal(
+    placesResult.resultCount,
+    0,
+    "Should know that we updated 0 items from the completion callback."
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_ignore_results() {
+  await PlacesUtils.history.clear();
+  let place = {
+    uri: NetUtil.newURI("http://mozilla.org/"),
+    title: "test",
+    visits: [new VisitInfo()],
+  };
+  let placesResult = await promiseUpdatePlaces(place, { ignoreResults: true });
+  Assert.equal(
+    placesResult.results.length,
+    0,
+    "Should have seen 0 results because we disabled reporting."
+  );
+  Assert.equal(
+    placesResult.errors.length,
+    0,
+    "Should have seen 0 errors because there were none."
+  );
+  Assert.equal(
+    placesResult.resultCount,
+    1,
+    "Should know that we updated 1 item from the completion callback."
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_ignore_results_and_errors() {
+  await PlacesUtils.history.clear();
+  // This test ensures that trying to add a visit, with a guid already found in
+  // another visit, fails - but doesn't report if we told it not to.
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_first"),
+    visits: [new VisitInfo()],
+  };
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(place.uri));
+  let placesResult = await promiseUpdatePlaces(place);
+  if (placesResult.errors.length) {
+    do_throw("Unexpected error.");
+  }
+  let placeInfo = placesResult.results[0];
+  Assert.ok(await PlacesUtils.history.hasVisits(placeInfo.uri));
+
+  let badPlace = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_duplicate_guid_fails_second"),
+    visits: [new VisitInfo()],
+    guid: placeInfo.guid,
+  };
+  let allPlaces = [
+    {
+      uri: NetUtil.newURI(TEST_DOMAIN + "test_other_successful_item"),
+      visits: [new VisitInfo()],
+    },
+    badPlace,
+  ];
+
+  Assert.equal(false, await PlacesUtils.history.hasVisits(badPlace.uri));
+  placesResult = await promiseUpdatePlaces(allPlaces, {
+    ignoreErrors: true,
+    ignoreResults: true,
+  });
+  Assert.equal(
+    placesResult.errors.length,
+    0,
+    "Should have seen 0 errors because we disabled reporting."
+  );
+  Assert.equal(
+    placesResult.results.length,
+    0,
+    "Should have seen 0 results because we disabled reporting."
+  );
+  Assert.equal(
+    placesResult.resultCount,
+    1,
+    "Should know that we updated 1 item from the completion callback."
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_title_on_initial_visit() {
+  let place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_visit_title"),
+    title: "My title",
+    visits: [new VisitInfo()],
+    guid: "mnopqrstuvwx",
+  };
+  let visitPromise = new Promise(resolve => {
+    new VisitObserver(place.uri, place.guid, function (
+      aVisitDate,
+      aTransitionType,
+      aLastKnownTitle
+    ) {
+      Assert.equal(place.title, aLastKnownTitle);
+
+      resolve();
+    });
+  });
+  await promiseUpdatePlaces(place);
+  await visitPromise;
+
+  // Now check an empty title doesn't get reported as null
+  place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_visit_title"),
+    title: "",
+    visits: [new VisitInfo()],
+    guid: "fghijklmnopq",
+  };
+  visitPromise = new Promise(resolve => {
+    new VisitObserver(place.uri, place.guid, function (
+      aVisitDate,
+      aTransitionType,
+      aLastKnownTitle
+    ) {
+      Assert.equal(place.title, aLastKnownTitle);
+
+      resolve();
+    });
+  });
+  await promiseUpdatePlaces(place);
+  await visitPromise;
+
+  // and that a missing title correctly gets reported as null.
+  place = {
+    uri: NetUtil.newURI(TEST_DOMAIN + "test_visit_title"),
+    visits: [new VisitInfo()],
+    guid: "fghijklmnopq",
+  };
+  visitPromise = new Promise(resolve => {
+    new VisitObserver(place.uri, place.guid, function (
+      aVisitDate,
+      aTransitionType,
+      aLastKnownTitle
+    ) {
+      Assert.equal(null, aLastKnownTitle);
+
+      resolve();
+    });
+  });
+  await promiseUpdatePlaces(place);
+  await visitPromise;
+});
diff --git a/toolkit/components/places/tests/history/test_bookmark_unhide.js b/toolkit/components/places/tests/history/test_bookmark_unhide.js
new file mode 100644
index 0000000000..1295c6e8c5
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_bookmark_unhide.js
@@ -0,0 +1,26 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that bookmarking an hidden page unhides it.
+
+"use strict";
+
+add_task(async function test_hidden() {
+  const url = "http://moz.com/";
+  await PlacesTestUtils.addVisits({
+    url,
+    transition: TRANSITION_FRAMED_LINK,
+  });
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", { url }),
+    1
+  );
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "hidden", { url }),
+    0
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_fetch.js b/toolkit/components/places/tests/history/test_fetch.js
new file mode 100644
index 0000000000..899e459403
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_fetch.js
@@ -0,0 +1,270 @@
+/* Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+add_task(async function test_fetch_existent() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Populate places and historyvisits.
+  let uriString = `http://mozilla.com/test_browserhistory/test_fetch`;
+  let uri = NetUtil.newURI(uriString);
+  let title = `Test Visit ${Math.random()}`;
+  let dates = [];
+  let visits = [];
+  let transitions = [
+    PlacesUtils.history.TRANSITION_LINK,
+    PlacesUtils.history.TRANSITION_TYPED,
+    PlacesUtils.history.TRANSITION_BOOKMARK,
+    PlacesUtils.history.TRANSITION_REDIRECT_TEMPORARY,
+    PlacesUtils.history.TRANSITION_REDIRECT_PERMANENT,
+    PlacesUtils.history.TRANSITION_DOWNLOAD,
+    PlacesUtils.history.TRANSITION_FRAMED_LINK,
+    PlacesUtils.history.TRANSITION_RELOAD,
+  ];
+  let guid = "";
+  for (let i = 0; i != transitions.length; i++) {
+    dates.push(new Date(Date.now() - i * 10000000));
+    visits.push({
+      uri,
+      title,
+      transition: transitions[i],
+      visitDate: dates[i],
+    });
+  }
+  await PlacesTestUtils.addVisits(visits);
+  Assert.ok(await PlacesTestUtils.isPageInDB(uri));
+  Assert.equal(await PlacesTestUtils.visitsInDB(uri), visits.length);
+
+  // Store guid for further use in testing.
+  guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: uri,
+  });
+  Assert.ok(guid, guid);
+
+  // Initialize the objects to compare against.
+  let idealPageInfo = {
+    url: new URL(uriString),
+    guid,
+    title,
+  };
+  let idealVisits = visits.map(v => {
+    return {
+      date: v.visitDate,
+      transition: v.transition,
+    };
+  });
+
+  // We should check these 4 cases:
+  // 1, 2: visits not included, by URL and guid (same result expected).
+  // 3, 4: visits included, by URL and guid (same result expected).
+  for (let includeVisits of [true, false]) {
+    for (let guidOrURL of [uri, guid]) {
+      let pageInfo = await PlacesUtils.history.fetch(guidOrURL, {
+        includeVisits,
+      });
+      if (includeVisits) {
+        idealPageInfo.visits = idealVisits;
+      } else {
+        // We need to explicitly delete this property since deepEqual looks at
+        // the list of properties as well (`visits in pageInfo` is true here).
+        delete idealPageInfo.visits;
+      }
+
+      // Since idealPageInfo doesn't contain a frecency, check it and delete.
+      Assert.ok(typeof pageInfo.frecency === "number");
+      delete pageInfo.frecency;
+
+      // Visits should be from newer to older.
+      if (includeVisits) {
+        for (let i = 0; i !== pageInfo.visits.length - 1; i++) {
+          Assert.lessOrEqual(
+            pageInfo.visits[i + 1].date.getTime(),
+            pageInfo.visits[i].date.getTime()
+          );
+        }
+      }
+      Assert.deepEqual(idealPageInfo, pageInfo);
+    }
+  }
+});
+
+add_task(async function test_fetch_page_meta_info() {
+  await PlacesUtils.history.clear();
+
+  let TEST_URI = NetUtil.newURI("http://mozilla.com/test_fetch_page_meta_info");
+  await PlacesTestUtils.addVisits(TEST_URI);
+  Assert.ok(page_in_database(TEST_URI));
+
+  // Test fetching the null values
+  let includeMeta = true;
+  let pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeMeta });
+  Assert.strictEqual(
+    null,
+    pageInfo.previewImageURL,
+    "fetch should return a null previewImageURL"
+  );
+  Assert.strictEqual(
+    "",
+    pageInfo.siteName,
+    "fetch should return a null siteName"
+  );
+  Assert.equal(
+    "",
+    pageInfo.description,
+    "fetch should return a empty string description"
+  );
+
+  // Now set the pageMetaInfo for this page
+  let description = "Test description";
+  let siteName = "Mozilla";
+  let previewImageURL = "http://mozilla.com/test_preview_image.png";
+  await PlacesUtils.history.update({
+    url: TEST_URI,
+    description,
+    previewImageURL,
+    siteName,
+  });
+
+  includeMeta = true;
+  pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeMeta });
+  Assert.equal(
+    previewImageURL,
+    pageInfo.previewImageURL.href,
+    "fetch should return a previewImageURL"
+  );
+  Assert.equal(siteName, pageInfo.siteName, "fetch should return a siteName");
+  Assert.equal(
+    description,
+    pageInfo.description,
+    "fetch should return a description"
+  );
+
+  includeMeta = false;
+  pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeMeta });
+  Assert.ok(
+    !("description" in pageInfo),
+    "fetch should not return a description if includeMeta is false"
+  );
+  Assert.ok(
+    !("siteName" in pageInfo),
+    "fetch should not return a siteName if includeMeta is false"
+  );
+  Assert.ok(
+    !("previewImageURL" in pageInfo),
+    "fetch should not return a previewImageURL if includeMeta is false"
+  );
+});
+
+add_task(async function test_fetch_annotations() {
+  await PlacesUtils.history.clear();
+
+  const TEST_URI = "http://mozilla.com/test_fetch_page_meta_info";
+  await PlacesTestUtils.addVisits(TEST_URI);
+  Assert.ok(page_in_database(TEST_URI));
+
+  let includeAnnotations = true;
+  let pageInfo = await PlacesUtils.history.fetch(TEST_URI, {
+    includeAnnotations,
+  });
+  Assert.equal(
+    pageInfo.annotations.size,
+    0,
+    "fetch should return an empty annotation map"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URI,
+    annotations: new Map([["test/annotation", "testContent"]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeAnnotations });
+  Assert.equal(
+    pageInfo.annotations.size,
+    1,
+    "fetch should have only one annotation"
+  );
+
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    "testContent",
+    "fetch should return the expected annotation"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URI,
+    annotations: new Map([["test/annotation2", 123]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeAnnotations });
+  Assert.equal(
+    pageInfo.annotations.size,
+    2,
+    "fetch should have returned two annotations"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    "testContent",
+    "fetch should still have the first annotation"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    123,
+    "fetch should have the second annotation"
+  );
+
+  includeAnnotations = false;
+  pageInfo = await PlacesUtils.history.fetch(TEST_URI, { includeAnnotations });
+  Assert.ok(
+    !("annotations" in pageInfo),
+    "fetch should not return annotations if includeAnnotations is false"
+  );
+});
+
+add_task(async function test_fetch_nonexistent() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let uri = NetUtil.newURI("http://doesntexist.in.db");
+  let pageInfo = await PlacesUtils.history.fetch(uri);
+  Assert.equal(pageInfo, null);
+});
+
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.fetch("3"),
+    /TypeError: URL constructor: 3 is not a valid /
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetch({ not: "a valid string or guid" }),
+    /TypeError: Invalid url or guid/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetch("http://valid.uri.com", "not an object"),
+    /TypeError: options should be/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetch("http://valid.uri.com", null),
+    /TypeError: options should be/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.fetch("http://valid.uri.come", {
+        includeVisits: "not a boolean",
+      }),
+    /TypeError: includeVisits should be a/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.fetch("http://valid.uri.come", {
+        includeMeta: "not a boolean",
+      }),
+    /TypeError: includeMeta should be a/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.fetch("http://valid.url.com", {
+        includeAnnotations: "not a boolean",
+      }),
+    /TypeError: includeAnnotations should be a/
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_fetchAnnotatedPages.js b/toolkit/components/places/tests/history/test_fetchAnnotatedPages.js
new file mode 100644
index 0000000000..0f487e8090
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_fetchAnnotatedPages.js
@@ -0,0 +1,146 @@
+/* Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.fetchAnnotatedPages(),
+    /TypeError: annotations should be an Array and not null/,
+    "Should throw an exception for a null parameter"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetchAnnotatedPages("3"),
+    /TypeError: annotations should be an Array and not null/,
+    "Should throw an exception for a parameter of the wrong type"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetchAnnotatedPages([3]),
+    /TypeError: all annotation values should be strings/,
+    "Should throw an exception for a non-string annotation name"
+  );
+});
+
+add_task(async function test_fetchAnnotatedPages_no_matching() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  const TEST_URL = "http://example.com/1";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL),
+    "Should have inserted the page into the database."
+  );
+
+  let result = await PlacesUtils.history.fetchAnnotatedPages(["test/anno"]);
+
+  Assert.equal(result.size, 0, "Should be no items returned.");
+});
+
+add_task(async function test_fetchAnnotatedPages_simple_match() {
+  await PlacesUtils.history.clear();
+
+  const TEST_URL = "http://example.com/1";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL),
+    "Should have inserted the page into the database."
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/anno", "testContent"]]),
+  });
+
+  let result = await PlacesUtils.history.fetchAnnotatedPages(["test/anno"]);
+
+  Assert.equal(
+    result.size,
+    1,
+    "Should have returned one match for the annotation"
+  );
+
+  Assert.deepEqual(
+    result.get("test/anno"),
+    [
+      {
+        uri: new URL(TEST_URL),
+        content: "testContent",
+      },
+    ],
+    "Should have returned the page and its content for the annotation"
+  );
+});
+
+add_task(async function test_fetchAnnotatedPages_multiple_match() {
+  await PlacesUtils.history.clear();
+
+  const TEST_URL1 = "http://example.com/1";
+  const TEST_URL2 = "http://example.com/2";
+  const TEST_URL3 = "http://example.com/3";
+  await PlacesTestUtils.addVisits([
+    { uri: TEST_URL1 },
+    { uri: TEST_URL2 },
+    { uri: TEST_URL3 },
+  ]);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL1),
+    "Should have inserted the first page into the database."
+  );
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL2),
+    "Should have inserted the second page into the database."
+  );
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL3),
+    "Should have inserted the third page into the database."
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL1,
+    annotations: new Map([["test/anno", "testContent1"]]),
+  });
+
+  await PlacesUtils.history.update({
+    url: TEST_URL2,
+    annotations: new Map([
+      ["test/anno", "testContent2"],
+      ["test/anno2", 1234],
+    ]),
+  });
+
+  let result = await PlacesUtils.history.fetchAnnotatedPages([
+    "test/anno",
+    "test/anno2",
+  ]);
+
+  Assert.equal(
+    result.size,
+    2,
+    "Should have returned matches for both annotations"
+  );
+
+  Assert.deepEqual(
+    result.get("test/anno"),
+    [
+      {
+        uri: new URL(TEST_URL1),
+        content: "testContent1",
+      },
+      {
+        uri: new URL(TEST_URL2),
+        content: "testContent2",
+      },
+    ],
+    "Should have returned two pages and their content for the first annotation"
+  );
+
+  Assert.deepEqual(
+    result.get("test/anno2"),
+    [
+      {
+        uri: new URL(TEST_URL2),
+        content: 1234,
+      },
+    ],
+    "Should have returned one page for the second annotation"
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_fetchMany.js b/toolkit/components/places/tests/history/test_fetchMany.js
new file mode 100644
index 0000000000..53c3f6847e
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_fetchMany.js
@@ -0,0 +1,96 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function test_fetchMany() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let pages = [
+    {
+      url: "https://mozilla.org/test1/",
+      title: "test 1",
+    },
+    {
+      url: "https://mozilla.org/test2/",
+      title: "test 2",
+    },
+    {
+      url: "https://mozilla.org/test3/",
+      title: "test 3",
+    },
+  ];
+  await PlacesTestUtils.addVisits(pages);
+
+  // Add missing page info from the database.
+  for (let page of pages) {
+    page.guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+      url: page.url,
+    });
+    page.frecency = await PlacesTestUtils.getDatabaseValue(
+      "moz_places",
+      "frecency",
+      { url: page.url }
+    );
+  }
+
+  info("Fetch by url");
+  let fetched = await PlacesUtils.history.fetchMany(pages.map(p => p.url));
+  Assert.equal(fetched.size, 3, "Map should contain same number of entries");
+  for (let page of pages) {
+    Assert.deepEqual(page, fetched.get(page.url));
+  }
+  info("Fetch by GUID");
+  fetched = await PlacesUtils.history.fetchMany(pages.map(p => p.guid));
+  Assert.equal(fetched.size, 3, "Map should contain same number of entries");
+  for (let page of pages) {
+    Assert.deepEqual(page, fetched.get(page.guid));
+  }
+  info("Fetch mixed");
+  let keys = pages.map((p, i) => (i % 2 == 0 ? p.guid : p.url));
+  fetched = await PlacesUtils.history.fetchMany(keys);
+  Assert.equal(fetched.size, 3, "Map should contain same number of entries");
+  for (let key of keys) {
+    let page = pages.find(p => p.guid == key || p.url == key);
+    Assert.deepEqual(page, fetched.get(key));
+    Assert.ok(URL.isInstance(fetched.get(key).url));
+  }
+});
+
+add_task(async function test_fetch_empty() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let fetched = await PlacesUtils.history.fetchMany([]);
+  Assert.equal(fetched.size, 0, "Map should contain no entries");
+});
+
+add_task(async function test_fetch_nonexistent() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let uri = NetUtil.newURI("http://doesntexist.in.db");
+  let fetched = await PlacesUtils.history.fetchMany([uri]);
+  Assert.equal(fetched.size, 0, "Map should contain no entries");
+});
+
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.fetchMany("3"),
+    /TypeError: Input is not an array/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetchMany([{ not: "a valid string or guid" }]),
+    /TypeError: Invalid url or guid/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.fetchMany(["http://valid.uri.com", "not an object"]),
+    /TypeError: URL constructor/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.fetchMany(["http://valid.uri.com", null]),
+    /TypeError: Invalid url or guid/
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_hasVisits.js b/toolkit/components/places/tests/history/test_hasVisits.js
new file mode 100644
index 0000000000..36fc9fd7be
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_hasVisits.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests for `History.hasVisits` as implemented in History.jsm
+
+"use strict";
+
+add_task(async function test_has_visits_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.hasVisits(),
+    /TypeError: Invalid url or guid: undefined/,
+    "passing a null into History.hasVisits should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.hasVisits(1),
+    /TypeError: Invalid url or guid: 1/,
+    "passing an invalid url into History.hasVisits should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.hasVisits({}),
+    /TypeError: Invalid url or guid: \[object Object\]/,
+    `passing an invalid (not of type URI or nsIURI) object to History.hasVisits
+     should throw a TypeError`
+  );
+});
+
+add_task(async function test_history_has_visits() {
+  const TEST_URL = "http://mozilla.com/";
+  await PlacesUtils.history.clear();
+  Assert.equal(
+    await PlacesUtils.history.hasVisits(TEST_URL),
+    false,
+    "Test Url should not be in history."
+  );
+  Assert.equal(
+    await PlacesUtils.history.hasVisits(Services.io.newURI(TEST_URL)),
+    false,
+    "Test Url should not be in history."
+  );
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.equal(
+    await PlacesUtils.history.hasVisits(TEST_URL),
+    true,
+    "Test Url should be in history."
+  );
+  Assert.equal(
+    await PlacesUtils.history.hasVisits(Services.io.newURI(TEST_URL)),
+    true,
+    "Test Url should be in history."
+  );
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: TEST_URL,
+  });
+  Assert.equal(
+    await PlacesUtils.history.hasVisits(guid),
+    true,
+    "Test Url should be in history."
+  );
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/history/test_insert.js b/toolkit/components/places/tests/history/test_insert.js
new file mode 100644
index 0000000000..a3a820ade9
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_insert.js
@@ -0,0 +1,196 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests for `History.insert` as implemented in History.jsm
+
+"use strict";
+
+add_task(async function test_insert_error_cases() {
+  const TEST_URL = "http://mozilla.com";
+
+  Assert.throws(
+    () => PlacesUtils.history.insert(),
+    /Error: PageInfo: Input should be /,
+    "passing a null into History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert(1),
+    /Error: PageInfo: Input should be/,
+    "passing a non object into History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert({}),
+    /Error: PageInfo: The following properties were expected/,
+    "passing an object without a url to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert({ url: 123 }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing an object with an invalid url to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert({ url: TEST_URL }),
+    /Error: PageInfo: The following properties were expected/,
+    "passing an object without a visits property to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert({ url: TEST_URL, visits: 1 }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing an object with a non-array visits property to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insert({ url: TEST_URL, visits: [] }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing an object with an empty array as the visits property to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.insert({
+        url: TEST_URL,
+        visits: [
+          {
+            transition: TRANSITION_LINK,
+            date: "a",
+          },
+        ],
+      }),
+    /PageInfo: Invalid value for property/,
+    "passing a visit object with an invalid date to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.insert({
+        url: TEST_URL,
+        visits: [
+          {
+            transition: TRANSITION_LINK,
+          },
+          {
+            transition: TRANSITION_LINK,
+            date: "a",
+          },
+        ],
+      }),
+    /PageInfo: Invalid value for property/,
+    "passing a second visit object with an invalid date to History.insert should throw an Error"
+  );
+  let futureDate = new Date();
+  futureDate.setDate(futureDate.getDate() + 1000);
+  Assert.throws(
+    () =>
+      PlacesUtils.history.insert({
+        url: TEST_URL,
+        visits: [
+          {
+            transition: TRANSITION_LINK,
+            date: futureDate,
+          },
+        ],
+      }),
+    /PageInfo: Invalid value for property/,
+    "passing a visit object with a future date to History.insert should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.insert({
+        url: TEST_URL,
+        visits: [{ transition: "a" }],
+      }),
+    /PageInfo: Invalid value for property/,
+    "passing a visit object with an invalid transition to History.insert should throw an Error"
+  );
+});
+
+add_task(async function test_history_insert() {
+  const TEST_URL = "http://mozilla.com/";
+
+  let inserter = async function (name, filter, referrer, date, transition) {
+    info(name);
+    info(
+      `filter: ${filter}, referrer: ${referrer}, date: ${date}, transition: ${transition}`
+    );
+
+    let uri = NetUtil.newURI(TEST_URL + Math.random());
+    let title = "Visit " + Math.random();
+
+    let pageInfo = {
+      title,
+      visits: [{ transition, referrer, date }],
+    };
+
+    pageInfo.url = await filter(uri);
+
+    let result = await PlacesUtils.history.insert(pageInfo);
+
+    Assert.ok(
+      PlacesUtils.isValidGuid(result.guid),
+      "guid for pageInfo object is valid"
+    );
+    Assert.equal(
+      uri.spec,
+      result.url.href,
+      "url is correct for pageInfo object"
+    );
+    Assert.equal(title, result.title, "title is correct for pageInfo object");
+    Assert.equal(
+      TRANSITION_LINK,
+      result.visits[0].transition,
+      "transition is correct for pageInfo object"
+    );
+    if (referrer) {
+      Assert.equal(
+        referrer,
+        result.visits[0].referrer.href,
+        "url of referrer for visit is correct"
+      );
+    } else {
+      Assert.equal(
+        null,
+        result.visits[0].referrer,
+        "url of referrer for visit is correct"
+      );
+    }
+    if (date) {
+      Assert.equal(
+        Number(date),
+        Number(result.visits[0].date),
+        "date of visit is correct"
+      );
+    }
+
+    Assert.ok(await PlacesTestUtils.isPageInDB(uri), "Page was added");
+    Assert.ok(await PlacesTestUtils.visitsInDB(uri), "Visit was added");
+  };
+
+  try {
+    for (let referrer of [TEST_URL, null]) {
+      for (let date of [new Date(), null]) {
+        for (let transition of [TRANSITION_LINK, null]) {
+          await inserter(
+            "Testing History.insert() with an nsIURI",
+            x => x,
+            referrer,
+            date,
+            transition
+          );
+          await inserter(
+            "Testing History.insert() with a string url",
+            x => x.spec,
+            referrer,
+            date,
+            transition
+          );
+          await inserter(
+            "Testing History.insert() with a URL object",
+            x => URL.fromURI(x),
+            referrer,
+            date,
+            transition
+          );
+        }
+      }
+    }
+  } finally {
+    await PlacesUtils.history.clear();
+  }
+});
diff --git a/toolkit/components/places/tests/history/test_insertMany.js b/toolkit/components/places/tests/history/test_insertMany.js
new file mode 100644
index 0000000000..b2cf60ed91
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_insertMany.js
@@ -0,0 +1,248 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests for `History.insertMany` as implemented in History.jsm
+
+"use strict";
+
+add_task(async function test_error_cases() {
+  let validPageInfo = {
+    url: "http://mozilla.com",
+    visits: [{ transition: TRANSITION_LINK }],
+  };
+
+  Assert.throws(
+    () => PlacesUtils.history.insertMany(),
+    /TypeError: pageInfos must be an array/,
+    "passing a null into History.insertMany should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insertMany([]),
+    /TypeError: pageInfos may not be an empty array/,
+    "passing an empty array into History.insertMany should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.insertMany([validPageInfo, {}]),
+    /Error: PageInfo: The following properties were expected/,
+    "passing a second invalid PageInfo object to History.insertMany should throw an Error"
+  );
+});
+
+add_task(async function test_insertMany() {
+  const BAD_URLS = ["about:config", "chrome://browser/content/browser.xhtml"];
+  const GOOD_URLS = [1, 2, 3].map(x => {
+    return `http://mozilla.com/${x}`;
+  });
+
+  let makePageInfos = async function (urls, filter = x => x) {
+    let pageInfos = [];
+    for (let url of urls) {
+      let uri = NetUtil.newURI(url);
+
+      let pageInfo = {
+        title: `Visit to ${url}`,
+        visits: [{ transition: TRANSITION_LINK }],
+      };
+
+      pageInfo.url = await filter(uri);
+      pageInfos.push(pageInfo);
+    }
+    return pageInfos;
+  };
+
+  let inserter = async function (name, filter, useCallbacks) {
+    info(name);
+    info(`filter: ${filter}`);
+    info(`useCallbacks: ${useCallbacks}`);
+    await PlacesUtils.history.clear();
+
+    let result;
+    let allUrls = GOOD_URLS.concat(BAD_URLS);
+    let pageInfos = await makePageInfos(allUrls, filter);
+
+    if (useCallbacks) {
+      let onResultUrls = [];
+      let onErrorUrls = [];
+      result = await PlacesUtils.history.insertMany(
+        pageInfos,
+        pageInfo => {
+          let url = pageInfo.url.href;
+          Assert.ok(
+            GOOD_URLS.includes(url),
+            "onResult callback called for correct url"
+          );
+          onResultUrls.push(url);
+          Assert.equal(
+            `Visit to ${url}`,
+            pageInfo.title,
+            "onResult callback provides the correct title"
+          );
+          Assert.ok(
+            PlacesUtils.isValidGuid(pageInfo.guid),
+            "onResult callback provides a valid guid"
+          );
+        },
+        pageInfo => {
+          let url = pageInfo.url.href;
+          Assert.ok(
+            BAD_URLS.includes(url),
+            "onError callback called for correct uri"
+          );
+          onErrorUrls.push(url);
+          Assert.equal(
+            undefined,
+            pageInfo.title,
+            "onError callback provides the correct title"
+          );
+          Assert.equal(
+            undefined,
+            pageInfo.guid,
+            "onError callback provides the expected guid"
+          );
+        }
+      );
+      Assert.equal(
+        GOOD_URLS.sort().toString(),
+        onResultUrls.sort().toString(),
+        "onResult callback was called for each good url"
+      );
+      Assert.equal(
+        BAD_URLS.sort().toString(),
+        onErrorUrls.sort().toString(),
+        "onError callback was called for each bad url"
+      );
+    } else {
+      const promiseRankingChanged =
+        PlacesTestUtils.waitForNotification("pages-rank-changed");
+      result = await PlacesUtils.history.insertMany(pageInfos);
+      await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+      await promiseRankingChanged;
+    }
+
+    Assert.equal(undefined, result, "insertMany returned undefined");
+
+    for (let url of allUrls) {
+      let expected = GOOD_URLS.includes(url);
+      Assert.equal(
+        expected,
+        await PlacesTestUtils.isPageInDB(url),
+        `isPageInDB for ${url} is ${expected}`
+      );
+      Assert.equal(
+        expected,
+        await PlacesTestUtils.visitsInDB(url),
+        `visitsInDB for ${url} is ${expected}`
+      );
+    }
+  };
+
+  try {
+    for (let useCallbacks of [false, true]) {
+      await inserter(
+        "Testing History.insertMany() with an nsIURI",
+        x => x,
+        useCallbacks
+      );
+      await inserter(
+        "Testing History.insertMany() with a string url",
+        x => x.spec,
+        useCallbacks
+      );
+      await inserter(
+        "Testing History.insertMany() with a URL object",
+        x => URL.fromURI(x),
+        useCallbacks
+      );
+    }
+    // Test rejection when no items added
+    let pageInfos = await makePageInfos(BAD_URLS);
+    PlacesUtils.history.insertMany(pageInfos).then(
+      () => {
+        Assert.ok(
+          false,
+          "History.insertMany rejected promise with all bad URLs"
+        );
+      },
+      error => {
+        Assert.equal(
+          "No items were added to history.",
+          error.message,
+          "History.insertMany rejected promise with all bad URLs"
+        );
+      }
+    );
+  } finally {
+    await PlacesUtils.history.clear();
+  }
+});
+
+add_task(async function test_transitions() {
+  const places = Object.keys(PlacesUtils.history.TRANSITIONS).map(
+    transition => {
+      return {
+        url: `http://places.test/${transition}`,
+        visits: [{ transition: PlacesUtils.history.TRANSITIONS[transition] }],
+      };
+    }
+  );
+  // Should not reject.
+  await PlacesUtils.history.insertMany(places);
+  // Check callbacks.
+  let count = 0;
+  await PlacesUtils.history.insertMany(places, pageInfo => {
+    ++count;
+  });
+  Assert.equal(count, Object.keys(PlacesUtils.history.TRANSITIONS).length);
+});
+
+add_task(async function test_guid() {
+  const guidA = "aaaaaaaaaaaa";
+  const guidB = "bbbbbbbbbbbb";
+  const guidC = "cccccccccccc";
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "foo",
+      url: "http://example.com/foo",
+      guid: guidA,
+      visits: [{ transition: TRANSITION_LINK, date: new Date() }],
+    },
+  ]);
+
+  Assert.ok(
+    await PlacesUtils.history.fetch(guidA),
+    "Record is inserted with correct GUID"
+  );
+
+  let expectedGuids = new Set([guidB, guidC]);
+  await PlacesUtils.history.insertMany(
+    [
+      {
+        title: "bar",
+        url: "http://example.com/bar",
+        guid: guidB,
+        visits: [{ transition: TRANSITION_LINK, date: new Date() }],
+      },
+      {
+        title: "baz",
+        url: "http://example.com/baz",
+        guid: guidC,
+        visits: [{ transition: TRANSITION_LINK, date: new Date() }],
+      },
+    ],
+    pageInfo => {
+      Assert.ok(expectedGuids.has(pageInfo.guid));
+      expectedGuids.delete(pageInfo.guid);
+    }
+  );
+  Assert.equal(expectedGuids.size, 0);
+
+  Assert.ok(
+    await PlacesUtils.history.fetch(guidB),
+    "Record B is fetchable after insertMany"
+  );
+  Assert.ok(
+    await PlacesUtils.history.fetch(guidC),
+    "Record C is fetchable after insertMany"
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_insert_null_title.js b/toolkit/components/places/tests/history/test_insert_null_title.js
new file mode 100644
index 0000000000..8cdcddd1e8
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_insert_null_title.js
@@ -0,0 +1,78 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that passing a null title to history insert or update doesn't overwrite
+// an existing title, while an empty string does.
+
+"use strict";
+
+async function fetchTitle(url) {
+  let entry;
+  await TestUtils.waitForCondition(async () => {
+    entry = await PlacesUtils.history.fetch(url);
+    return !!entry;
+  }, "fetch title for entry");
+  return entry.title;
+}
+
+add_task(async function () {
+  const url = "http://mozilla.com";
+  let title = "Mozilla";
+
+  info("Insert a visit with a title");
+  let result = await PlacesUtils.history.insert({
+    url,
+    title,
+    visits: [{ transition: PlacesUtils.history.TRANSITIONS.LINK }],
+  });
+  Assert.equal(title, result.title, "title should be stored");
+  Assert.equal(title, await fetchTitle(url), "title should be stored");
+
+  // This is shared by the next tests.
+  let promiseTitleChange = PlacesTestUtils.waitForNotification(
+    "page-title-changed",
+    () => (notified = true)
+  );
+
+  info("Insert a visit with a null title, should not clear the previous title");
+  let notified = false;
+  result = await PlacesUtils.history.insert({
+    url,
+    title: null,
+    visits: [{ transition: PlacesUtils.history.TRANSITIONS.LINK }],
+  });
+  Assert.equal(title, result.title, "title should be unchanged");
+  Assert.equal(title, await fetchTitle(url), "title should be unchanged");
+  await Promise.race([
+    promiseTitleChange,
+    new Promise(r => do_timeout(1000, r)),
+  ]);
+  Assert.ok(!notified, "A title change should not be notified");
+
+  info(
+    "Insert a visit without specifying a title, should not clear the previous title"
+  );
+  notified = false;
+  result = await PlacesUtils.history.insert({
+    url,
+    visits: [{ transition: PlacesUtils.history.TRANSITIONS.LINK }],
+  });
+  Assert.equal(title, result.title, "title should be unchanged");
+  Assert.equal(title, await fetchTitle(url), "title should be unchanged");
+  await Promise.race([
+    promiseTitleChange,
+    new Promise(r => do_timeout(1000, r)),
+  ]);
+  Assert.ok(!notified, "A title change should not be notified");
+
+  info("Insert a visit with an empty title, should clear the previous title");
+  result = await PlacesUtils.history.insert({
+    url,
+    title: "",
+    visits: [{ transition: PlacesUtils.history.TRANSITIONS.LINK }],
+  });
+  info("Waiting for the title change notification");
+  await promiseTitleChange;
+  Assert.equal("", result.title, "title should be empty");
+  Assert.equal("", await fetchTitle(url), "title should be empty");
+});
diff --git a/toolkit/components/places/tests/history/test_remove.js b/toolkit/components/places/tests/history/test_remove.js
new file mode 100644
index 0000000000..8c5e941fd0
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_remove.js
@@ -0,0 +1,354 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+// Tests for `History.remove`, as implemented in History.jsm
+
+"use strict";
+
+// Test removing a single page
+add_task(async function test_remove_single() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  let WITNESS_URI = NetUtil.newURI(
+    "http://mozilla.com/test_browserhistory/test_remove/" + Math.random()
+  );
+  await PlacesTestUtils.addVisits(WITNESS_URI);
+  Assert.ok(page_in_database(WITNESS_URI));
+
+  let remover = async function (name, filter, options) {
+    info(name);
+    info(JSON.stringify(options));
+    info("Setting up visit");
+
+    let uri = NetUtil.newURI(
+      "http://mozilla.com/test_browserhistory/test_remove/" + Math.random()
+    );
+    let title = "Visit " + Math.random();
+    await PlacesTestUtils.addVisits({ uri, title });
+    Assert.ok(visits_in_database(uri), "History entry created");
+
+    let removeArg = await filter(uri);
+
+    if (options.addBookmark) {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: uri,
+        title: "test bookmark",
+      });
+    }
+
+    let shouldRemove = !options.addBookmark;
+    let placesEventListener;
+    let promiseObserved = new Promise((resolve, reject) => {
+      placesEventListener = events => {
+        for (const event of events) {
+          switch (event.type) {
+            case "page-title-changed": {
+              reject(
+                "Unexpected page-title-changed event happens on " + event.url
+              );
+              break;
+            }
+            case "history-cleared": {
+              reject("Unexpected history-cleared event happens");
+              break;
+            }
+            case "pages-rank-changed": {
+              try {
+                Assert.ok(!shouldRemove, "Observing pages-rank-changed event");
+              } finally {
+                resolve();
+              }
+              break;
+            }
+            case "page-removed": {
+              Assert.equal(
+                event.isRemovedFromStore,
+                shouldRemove,
+                "Observe page-removed event with right removal type"
+              );
+              Assert.equal(
+                event.url,
+                uri.spec,
+                "Observing effect on the right uri"
+              );
+              resolve();
+              break;
+            }
+          }
+        }
+      };
+    });
+    PlacesObservers.addListener(
+      [
+        "page-title-changed",
+        "history-cleared",
+        "pages-rank-changed",
+        "page-removed",
+      ],
+      placesEventListener
+    );
+
+    info("Performing removal");
+    let removed = false;
+    if (options.useCallback) {
+      let onRowCalled = false;
+      let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+        url: uri,
+      });
+      removed = await PlacesUtils.history.remove(removeArg, page => {
+        Assert.equal(onRowCalled, false, "Callback has not been called yet");
+        onRowCalled = true;
+        Assert.equal(
+          page.url.href,
+          uri.spec,
+          "Callback provides the correct url"
+        );
+        Assert.equal(page.guid, guid, "Callback provides the correct guid");
+        Assert.equal(page.title, title, "Callback provides the correct title");
+      });
+      Assert.ok(onRowCalled, "Callback has been called");
+    } else {
+      removed = await PlacesUtils.history.remove(removeArg);
+    }
+
+    await promiseObserved;
+    PlacesObservers.removeListener(
+      [
+        "page-title-changed",
+        "history-cleared",
+        "pages-rank-changed",
+        "page-removed",
+      ],
+      placesEventListener
+    );
+
+    Assert.equal(visits_in_database(uri), 0, "History entry has disappeared");
+    Assert.notEqual(
+      visits_in_database(WITNESS_URI),
+      0,
+      "Witness URI still has visits"
+    );
+    Assert.notEqual(
+      page_in_database(WITNESS_URI),
+      0,
+      "Witness URI is still here"
+    );
+    if (shouldRemove) {
+      Assert.ok(removed, "Something was removed");
+      Assert.equal(page_in_database(uri), 0, "Page has disappeared");
+    } else {
+      Assert.ok(!removed, "The page was not removed, as there was a bookmark");
+      Assert.notEqual(page_in_database(uri), 0, "The page is still present");
+    }
+  };
+
+  try {
+    for (let useCallback of [false, true]) {
+      for (let addBookmark of [false, true]) {
+        let options = { useCallback, addBookmark };
+        await remover(
+          "Testing History.remove() with a single URI",
+          x => x,
+          options
+        );
+        await remover(
+          "Testing History.remove() with a single string url",
+          x => x.spec,
+          options
+        );
+        await remover(
+          "Testing History.remove() with a single string guid",
+          async x =>
+            PlacesTestUtils.getDatabaseValue("moz_places", "guid", { url: x }),
+          options
+        );
+        await remover(
+          "Testing History.remove() with a single URI in an array",
+          x => [x],
+          options
+        );
+        await remover(
+          "Testing History.remove() with a single string url in an array",
+          x => [x.spec],
+          options
+        );
+        await remover(
+          "Testing History.remove() with a single string guid in an array",
+          x =>
+            PlacesTestUtils.getDatabaseValue("moz_places", "guid", { url: x }),
+          options
+        );
+      }
+    }
+  } finally {
+    await PlacesUtils.history.clear();
+  }
+});
+
+add_task(async function cleanup() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+// Test the various error cases
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.remove(),
+    /TypeError: Invalid url/,
+    "History.remove with no argument should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove(null),
+    /TypeError: Invalid url/,
+    "History.remove with `null` should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove(undefined),
+    /TypeError: Invalid url/,
+    "History.remove with `undefined` should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove("not a guid, obviously"),
+    /TypeError: .* is not a valid URL/,
+    "History.remove with an ill-formed guid/url argument should throw a TypeError"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.remove({
+        "not the kind of object we know how to handle": true,
+      }),
+    /TypeError: Invalid url/,
+    "History.remove with an unexpected object should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove([]),
+    /TypeError: Expected at least one page/,
+    "History.remove with an empty array should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove([null]),
+    /TypeError: Invalid url or guid/,
+    "History.remove with an array containing null should throw a TypeError"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.remove([
+        "http://example.org",
+        "not a guid, obviously",
+      ]),
+    /TypeError: .* is not a valid URL/,
+    "History.remove with an array containing an ill-formed guid/url argument should throw a TypeError"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.remove(["0123456789ab" /* valid guid*/, null]),
+    /TypeError: Invalid url or guid: null/,
+    "History.remove with an array containing a guid and a second argument that is null should throw a TypeError"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.remove([
+        "http://example.org",
+        { "not the kind of object we know how to handle": true },
+      ]),
+    /TypeError: Invalid url/,
+    "History.remove with an array containing an unexpected objecgt should throw a TypeError"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.remove(
+        "http://example.org",
+        "not a function, obviously"
+      ),
+    /TypeError: Invalid function/,
+    "History.remove with a second argument that is not a function argument should throw a TypeError"
+  );
+  try {
+    PlacesUtils.history.remove(
+      "http://example.org/I/have/clearly/not/been/added",
+      null
+    );
+    Assert.ok(true, "History.remove should ignore `null` as a second argument");
+  } catch (ex) {
+    Assert.ok(
+      false,
+      "History.remove should ignore `null` as a second argument"
+    );
+  }
+});
+
+add_task(async function test_orphans() {
+  let uri = NetUtil.newURI("http://moz.org/");
+  await PlacesTestUtils.addVisits({ uri });
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    uri,
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  // Also create a root icon.
+  let faviconURI = Services.io.newURI(uri.spec + "favicon.ico");
+  PlacesUtils.favicons.replaceFaviconDataFromDataURL(
+    faviconURI,
+    SMALLPNG_DATA_URI.spec,
+    0,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    uri,
+    faviconURI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+
+  await PlacesUtils.history.update({
+    url: uri,
+    annotations: new Map([["test", "restval"]]),
+  });
+
+  await PlacesUtils.history.remove(uri);
+  Assert.ok(
+    !(await PlacesTestUtils.isPageInDB(uri)),
+    "Page should have been removed"
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`SELECT (SELECT count(*) FROM moz_annos) +
+                                      (SELECT count(*) FROM moz_icons) +
+                                      (SELECT count(*) FROM moz_pages_w_icons) +
+                                      (SELECT count(*) FROM moz_icons_to_pages) AS count`);
+  Assert.equal(rows[0].getResultByName("count"), 0, "Should not find orphans");
+});
+
+add_task(async function test_remove_backslash() {
+  // Backslash is an escape char in Sqlite, we must take care of that when
+  // removing a url containing a backslash.
+  const url = "https://www.mozilla.org/?test=\u005C";
+  await PlacesTestUtils.addVisits(url);
+  Assert.ok(await PlacesUtils.history.remove(url), "A page should be removed");
+  Assert.deepEqual(
+    await PlacesUtils.history.fetch(url),
+    null,
+    "The page should not be found"
+  );
+});
+
+add_task(async function test_url_with_apices() {
+  // Apices may confuse code and cause injection if mishandled.
+  // The ideal test would be with a javascript url, because it would not be
+  // encoded by URL(), unfortunately it would also not be added to history.
+  const url = `http://mozilla.org/\u0022\u0027`;
+  await PlacesTestUtils.addVisits(url);
+  Assert.ok(await PlacesUtils.history.remove(url), "A page should be removed");
+  Assert.deepEqual(
+    await PlacesUtils.history.fetch(url),
+    null,
+    "The page should not be found"
+  );
+});
diff --git a/toolkit/components/places/tests/history/test_removeByFilter.js b/toolkit/components/places/tests/history/test_removeByFilter.js
new file mode 100644
index 0000000000..fb18bf8e74
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_removeByFilter.js
@@ -0,0 +1,497 @@
+"use strict";
+
+/*
+This test will ideally test the following cases
+(each with and without a callback associated with it)
+  Case A: Tests which should remove pages (Positives)
+    Case A 1: Page has multiple visits both in/out of timeframe, all get deleted
+    Case A 2: Page has single uri, removed by host
+    Case A 3: Page has random subhost, with same host, removed by wildcard
+    Case A 4: Page is localhost and localhost:port, removed by host
+    Case A 5: Page is a `file://` type address, removed by empty host
+    Cases A 1,2,3 will be tried with and without bookmarks added (which prevent page deletion)
+  Case B: Tests in which no pages are removed (Inverses)
+    Case B 1 (inverse): Page has no visits in timeframe, and nothing is deleted
+    Case B 2: Page has single uri, not removed since hostname is different
+    Case B 3: Page has multiple subhosts, not removed since wildcard doesn't match
+  Case C: Combinations tests
+    Case C 1: Single hostname, multiple visits, at least one in timeframe and hostname
+    Case C 2: Random subhosts, multiple visits, at least one in timeframe and hostname-wildcard
+*/
+
+add_task(async function test_removeByFilter() {
+  // Cleanup
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Adding a witness URI
+  let witnessURI = NetUtil.newURI(
+    "http://witnessmozilla.org/test_browserhistory/test_removeByFilter" +
+      Math.random()
+  );
+  await PlacesTestUtils.addVisits(witnessURI);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(witnessURI),
+    "Witness URI is in database"
+  );
+
+  let removeByFilterTester = async function (
+    visits,
+    filter,
+    checkBeforeRemove,
+    checkAfterRemove,
+    useCallback,
+    bookmarkedUri
+  ) {
+    // Add visits for URIs
+    await PlacesTestUtils.addVisits(visits);
+    if (
+      bookmarkedUri !== null &&
+      visits.map(v => v.uri).includes(bookmarkedUri)
+    ) {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: bookmarkedUri,
+        title: "test bookmark",
+      });
+    }
+    await checkBeforeRemove();
+
+    // Take care of any observers (due to bookmarks)
+    let { placesEventListener, promiseObserved } =
+      getObserverPromise(bookmarkedUri);
+    if (placesEventListener) {
+      PlacesObservers.addListener(
+        ["page-title-changed", "history-cleared", "page-removed"],
+        placesEventListener
+      );
+    }
+    // Perfom delete operation on database
+    let removed = false;
+    if (useCallback) {
+      // The amount of callbacks will be the unique URIs to remove from the database
+      let netCallbacksRequired = new Set(visits.map(v => v.uri)).size;
+      removed = await PlacesUtils.history.removeByFilter(filter, pageInfo => {
+        Assert.ok(
+          PlacesUtils.validatePageInfo(pageInfo, false),
+          "pageInfo should follow a basic format"
+        );
+        Assert.ok(
+          netCallbacksRequired > 0,
+          "Callback called as many times as required"
+        );
+        netCallbacksRequired--;
+      });
+    } else {
+      removed = await PlacesUtils.history.removeByFilter(filter);
+    }
+    await checkAfterRemove();
+    await promiseObserved;
+    if (placesEventListener) {
+      await PlacesUtils.bookmarks.eraseEverything();
+      PlacesObservers.removeListener(
+        ["page-title-changed", "history-cleared", "page-removed"],
+        placesEventListener
+      );
+    }
+    Assert.ok(
+      await PlacesTestUtils.isPageInDB(witnessURI),
+      "Witness URI is still in database"
+    );
+    return removed;
+  };
+
+  const remoteUriList = [
+    "http://mozilla.org/test_browserhistory/test_removeByFilter/" +
+      Math.random(),
+    "http://subdomain1.mozilla.org/test_browserhistory/test_removeByFilter/" +
+      Math.random(),
+    "http://subdomain2.mozilla.org/test_browserhistory/test_removeByFilter/" +
+      Math.random(),
+  ];
+  const localhostUriList = [
+    "http://localhost:4500/" + Math.random(),
+    "http://localhost/" + Math.random(),
+  ];
+  const fileUriList = ["file:///home/user/files" + Math.random()];
+  const title = "Title " + Math.random();
+  let sameHostVisits = [
+    {
+      uri: remoteUriList[0],
+      title,
+      visitDate: new Date(2005, 1, 1) * 1000,
+    },
+    {
+      uri: remoteUriList[0],
+      title,
+      visitDate: new Date(2005, 3, 3) * 1000,
+    },
+    {
+      uri: remoteUriList[0],
+      title,
+      visitDate: new Date(2007, 1, 1) * 1000,
+    },
+  ];
+  let randomHostVisits = [
+    {
+      uri: remoteUriList[0],
+      title,
+      visitDate: new Date(2005, 1, 1) * 1000,
+    },
+    {
+      uri: remoteUriList[1],
+      title,
+      visitDate: new Date(2005, 3, 3) * 1000,
+    },
+    {
+      uri: remoteUriList[2],
+      title,
+      visitDate: new Date(2007, 1, 1) * 1000,
+    },
+  ];
+  let localhostVisits = [
+    {
+      uri: localhostUriList[0],
+      title,
+    },
+    {
+      uri: localhostUriList[1],
+      title,
+    },
+  ];
+  let fileVisits = [
+    {
+      uri: fileUriList[0],
+      title,
+    },
+  ];
+  let assertInDB = async function (aUri) {
+    Assert.ok(await PlacesTestUtils.isPageInDB(aUri));
+  };
+  let assertNotInDB = async function (aUri) {
+    Assert.ok(!(await PlacesTestUtils.isPageInDB(aUri)));
+  };
+  for (let callbackUse of [true, false]) {
+    // Case A Positives
+    for (let bookmarkUse of [true, false]) {
+      let bookmarkedUri = arr => undefined;
+      let checkableArray = arr => arr;
+      let checkClosure = assertNotInDB;
+      if (bookmarkUse) {
+        bookmarkedUri = arr => arr[0];
+        checkableArray = arr => arr.slice(1);
+        checkClosure = function (aUri) {};
+      }
+      // Case A 1: Dates
+      await removeByFilterTester(
+        sameHostVisits,
+        { beginDate: new Date(2004, 1, 1), endDate: new Date(2006, 1, 1) },
+        () => assertInDB(remoteUriList[0]),
+        () => checkClosure(remoteUriList[0]),
+        callbackUse,
+        bookmarkedUri(remoteUriList)
+      );
+      // Case A 2: Single Sub-host
+      await removeByFilterTester(
+        sameHostVisits,
+        { host: "mozilla.org" },
+        () => assertInDB(remoteUriList[0]),
+        () => checkClosure(remoteUriList[0]),
+        callbackUse,
+        bookmarkedUri(remoteUriList)
+      );
+      // Case A 3: Multiple subhost
+      await removeByFilterTester(
+        randomHostVisits,
+        { host: ".mozilla.org" },
+        async () => {
+          for (let uri of remoteUriList) {
+            await assertInDB(uri);
+          }
+        },
+        async () => {
+          for (let uri of checkableArray(remoteUriList)) {
+            await checkClosure(uri);
+          }
+        },
+        callbackUse,
+        bookmarkedUri(remoteUriList)
+      );
+    }
+
+    // Case A 4: Localhost
+    await removeByFilterTester(
+      localhostVisits,
+      { host: "localhost" },
+      async () => {
+        for (let uri of localhostUriList) {
+          await assertInDB(uri);
+        }
+      },
+      async () => {
+        for (let uri of localhostUriList) {
+          await assertNotInDB(uri);
+        }
+      },
+      callbackUse
+    );
+    // Case A 5: Local Files
+    await removeByFilterTester(
+      fileVisits,
+      { host: "." },
+      async () => {
+        for (let uri of fileUriList) {
+          await assertInDB(uri);
+        }
+      },
+      async () => {
+        for (let uri of fileUriList) {
+          await assertNotInDB(uri);
+        }
+      },
+      callbackUse
+    );
+
+    // Case B: Tests which do not remove anything (inverses)
+    // Case B 1: Date
+    await removeByFilterTester(
+      sameHostVisits,
+      { beginDate: new Date(2001, 1, 1), endDate: new Date(2002, 1, 1) },
+      () => assertInDB(remoteUriList[0]),
+      () => assertInDB(remoteUriList[0]),
+      callbackUse
+    );
+    // Case B 2 : Single subhost
+    await removeByFilterTester(
+      sameHostVisits,
+      { host: "notthere.org" },
+      () => assertInDB(remoteUriList[0]),
+      () => assertInDB(remoteUriList[0]),
+      callbackUse
+    );
+    // Case B 3 : Multiple subhosts
+    await removeByFilterTester(
+      randomHostVisits,
+      { host: ".notthere.org" },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertInDB(uri);
+        }
+      },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertInDB(uri);
+        }
+      },
+      callbackUse
+    );
+    // Case B 4 : invalid local subhost
+    await removeByFilterTester(
+      randomHostVisits,
+      { host: ".org" },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertInDB(uri);
+        }
+      },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertInDB(uri);
+        }
+      },
+      callbackUse
+    );
+
+    // Case C: Combination Cases
+    // Case C 1: single subhost
+    await removeByFilterTester(
+      sameHostVisits,
+      {
+        host: "mozilla.org",
+        beginDate: new Date(2004, 1, 1),
+        endDate: new Date(2006, 1, 1),
+      },
+      () => assertInDB(remoteUriList[0]),
+      () => assertNotInDB(remoteUriList[0]),
+      callbackUse
+    );
+    // Case C 2: multiple subhost
+    await removeByFilterTester(
+      randomHostVisits,
+      {
+        host: ".mozilla.org",
+        beginDate: new Date(2005, 1, 1),
+        endDate: new Date(2017, 1, 1),
+      },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertInDB(uri);
+        }
+      },
+      async () => {
+        for (let uri of remoteUriList) {
+          await assertNotInDB(uri);
+        }
+      },
+      callbackUse
+    );
+  }
+});
+
+// Test various error cases
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter(),
+    /TypeError: Expected a filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter("obviously, not a filter"),
+    /TypeError: Expected a filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({}),
+    /TypeError: Expected a non-empty filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ beginDate: "now" }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ beginDate: Date.now() }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ beginDate: new Date(NaN) }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeByFilter(
+        { beginDate: new Date() },
+        "obviously, not a callback"
+      ),
+    /TypeError: Invalid function/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeByFilter({
+        beginDate: new Date(1000),
+        endDate: new Date(0),
+      }),
+    /TypeError: `beginDate` should be at least as old/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "#" }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "www..org" }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: {} }),
+    /TypeError: `host` should be a string/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "*.mozilla.org" }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "*" }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "local.host." }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "(local files)" }),
+    /TypeError: Expected well formed hostname string for/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeByFilter({ host: "" }),
+    /TypeError: Expected a non-empty filter/
+  );
+});
+
+add_task(async function test_chunking() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  info("Insert many visited pages");
+  let pages = [];
+  for (let i = 1; i <= 1500; i++) {
+    let visits = [
+      {
+        date: new Date(Date.now() - (86400 + i) * 1000),
+        transition: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+    ];
+    pages.push(
+      {
+        url: `http://example.com/${i}`,
+        title: `Page ${i}`,
+        visits,
+      },
+      {
+        url: `http://subdomain.example.com/${i}`,
+        title: `Subdomain ${i}`,
+        visits,
+      }
+    );
+  }
+  await PlacesUtils.history.insertMany(pages);
+
+  info("Remove all visited pages");
+  await PlacesUtils.history.removeByFilter({
+    host: ".example.com",
+  });
+});
+
+// Helper functions
+
+function getObserverPromise(bookmarkedUri) {
+  if (!bookmarkedUri) {
+    return { promiseObserved: Promise.resolve() };
+  }
+  let placesEventListener;
+  let promiseObserved = new Promise((resolve, reject) => {
+    placesEventListener = events => {
+      for (const event of events) {
+        switch (event.type) {
+          case "page-title-changed": {
+            reject(new Error("Unexpected page-title-changed event happens"));
+            break;
+          }
+          case "history-cleared": {
+            reject(new Error("Unexpected history-cleared event happens"));
+            break;
+          }
+          case "page-removed": {
+            if (event.isRemovedFromStore) {
+              Assert.notEqual(
+                event.url,
+                bookmarkedUri,
+                "Bookmarked URI should not be deleted"
+              );
+            } else {
+              Assert.equal(
+                event.isPartialVisistsRemoval,
+                false,
+                "Observing page-removed deletes all visits"
+              );
+              Assert.equal(
+                event.url,
+                bookmarkedUri,
+                "Bookmarked URI should have all visits removed but not the page itself"
+              );
+            }
+            resolve();
+            break;
+          }
+        }
+      }
+    };
+  });
+  return { placesEventListener, promiseObserved };
+}
diff --git a/toolkit/components/places/tests/history/test_removeMany.js b/toolkit/components/places/tests/history/test_removeMany.js
new file mode 100644
index 0000000000..ff8c3a21ee
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_removeMany.js
@@ -0,0 +1,206 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+// Tests for `History.remove` with removing many urls, as implemented in
+// History.jsm.
+
+"use strict";
+
+// Test removing a list of pages
+add_task(async function test_remove_many() {
+  // This is set so that we are guaranteed to trigger REMOVE_PAGES_CHUNKLEN.
+  const SIZE = 310;
+
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  info("Adding a witness page");
+  let WITNESS_URI = NetUtil.newURI(
+    "http://mozilla.com/test_browserhistory/test_remove/" + Math.random()
+  );
+  await PlacesTestUtils.addVisits(WITNESS_URI);
+  Assert.ok(page_in_database(WITNESS_URI), "Witness page added");
+
+  info("Generating samples");
+  let pages = [];
+  for (let i = 0; i < SIZE; ++i) {
+    let uri = NetUtil.newURI(
+      "http://mozilla.com/test_browserhistory/test_remove?sample=" +
+        i +
+        "&salt=" +
+        Math.random()
+    );
+    let title = "Visit " + i + ", " + Math.random();
+    let hasBookmark = i % 3 == 0;
+    let page = {
+      uri,
+      title,
+      hasBookmark,
+      // `true` once `onResult` has been called for this page
+      onResultCalled: false,
+      // `true` once page-removed for store has been fired for this page
+      pageRemovedFromStore: false,
+      // `true` once page-removed for all visits has been fired for this page
+      pageRemovedAllVisits: false,
+    };
+    info("Pushing: " + uri.spec);
+    pages.push(page);
+
+    await PlacesTestUtils.addVisits(page);
+    page.guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+      url: uri,
+    });
+    if (hasBookmark) {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: uri,
+        title: "test bookmark " + i,
+      });
+    }
+    Assert.ok(page_in_database(uri), "Page added");
+  }
+
+  info("Mixing key types and introducing dangling keys");
+  let keys = [];
+  for (let i = 0; i < SIZE; ++i) {
+    if (i % 4 == 0) {
+      keys.push(pages[i].uri);
+      keys.push(NetUtil.newURI("http://example.org/dangling/nsIURI/" + i));
+    } else if (i % 4 == 1) {
+      keys.push(new URL(pages[i].uri.spec));
+      keys.push(new URL("http://example.org/dangling/URL/" + i));
+    } else if (i % 4 == 2) {
+      keys.push(pages[i].uri.spec);
+      keys.push("http://example.org/dangling/stringuri/" + i);
+    } else {
+      keys.push(pages[i].guid);
+      keys.push(("guid_" + i + "_01234567890").substr(0, 12));
+    }
+  }
+
+  let onPageRankingChanged = false;
+  const placesEventListener = events => {
+    for (const event of events) {
+      switch (event.type) {
+        case "page-title-changed": {
+          Assert.ok(
+            false,
+            "Unexpected page-title-changed event happens on " + event.url
+          );
+          break;
+        }
+        case "history-cleared": {
+          Assert.ok(false, "Unexpected history-cleared event happens");
+          break;
+        }
+        case "pages-rank-changed": {
+          onPageRankingChanged = true;
+          break;
+        }
+        case "page-removed": {
+          const origin = pages.find(x => x.uri.spec === event.url);
+          Assert.ok(origin);
+
+          if (event.isRemovedFromStore) {
+            Assert.ok(
+              !origin.hasBookmark,
+              "Observing page-removed event on a page without a bookmark"
+            );
+            Assert.ok(
+              !origin.pageRemovedFromStore,
+              "Observing page-removed for store for the first time"
+            );
+            origin.pageRemovedFromStore = true;
+          } else {
+            Assert.ok(
+              !origin.pageRemovedAllVisits,
+              "Observing page-removed for all visits for the first time"
+            );
+            origin.pageRemovedAllVisits = true;
+          }
+          break;
+        }
+      }
+    }
+  };
+
+  PlacesObservers.addListener(
+    [
+      "page-title-changed",
+      "history-cleared",
+      "pages-rank-changed",
+      "page-removed",
+    ],
+    placesEventListener
+  );
+
+  info("Removing the pages and checking the callbacks");
+
+  let removed = await PlacesUtils.history.remove(keys, page => {
+    let origin = pages.find(candidate => candidate.uri.spec == page.url.href);
+
+    Assert.ok(origin, "onResult has a valid page");
+    Assert.ok(!origin.onResultCalled, "onResult has not seen this page yet");
+    origin.onResultCalled = true;
+    Assert.equal(page.guid, origin.guid, "onResult has the right guid");
+    Assert.equal(page.title, origin.title, "onResult has the right title");
+  });
+  Assert.ok(removed, "Something was removed");
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  PlacesObservers.removeListener(
+    [
+      "page-title-changed",
+      "history-cleared",
+      "pages-rank-changed",
+      "page-removed",
+    ],
+    placesEventListener
+  );
+
+  info("Checking out results");
+  // By now the observers should have been called.
+  for (let i = 0; i < pages.length; ++i) {
+    let page = pages[i];
+    Assert.ok(
+      page.onResultCalled,
+      `We have reached the page #${i} from the callback`
+    );
+    Assert.ok(
+      visits_in_database(page.uri) == 0,
+      "History entry has disappeared"
+    );
+    Assert.equal(
+      page_in_database(page.uri) != 0,
+      page.hasBookmark,
+      "Page is present only if it also has bookmarks"
+    );
+    Assert.notEqual(
+      page.pageRemovedFromStore,
+      page.pageRemovedAllVisits,
+      "Either only page-removed event for store or all visits should be called"
+    );
+  }
+
+  Assert.equal(
+    onPageRankingChanged,
+    pages.some(p => p.pageRemovedFromStore || p.pageRemovedAllVisits),
+    "page-rank-changed was fired"
+  );
+
+  Assert.notEqual(
+    visits_in_database(WITNESS_URI),
+    0,
+    "Witness URI still has visits"
+  );
+  Assert.notEqual(
+    page_in_database(WITNESS_URI),
+    0,
+    "Witness URI is still here"
+  );
+});
+
+add_task(async function cleanup() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/history/test_removeVisits.js b/toolkit/components/places/tests/history/test_removeVisits.js
new file mode 100644
index 0000000000..3a82132bd8
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_removeVisits.js
@@ -0,0 +1,376 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const JS_NOW = Date.now();
+const DB_NOW = JS_NOW * 1000;
+const TEST_URI = uri("http://example.com/");
+
+async function cleanup() {
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+  // This is needed to remove place: entries.
+  DBConn().executeSimpleSQL("DELETE FROM moz_places");
+}
+
+add_task(async function remove_visits_outside_unbookmarked_uri() {
+  info(
+    "*** TEST: Remove some visits outside valid timeframe from an unbookmarked URI"
+  );
+
+  info("Add 10 visits for the URI from way in the past.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - 100000 - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+
+  info("Remove visits using timerange outside the URI's visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 10),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+
+  info("Run a history query and check that all visits still exist.");
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 10);
+  for (let i = 0; i < root.childCount; i++) {
+    let visitTime = root.getChild(i).time;
+    Assert.equal(visitTime, DB_NOW - 100000 - i * 1000);
+  }
+  root.containerOpen = false;
+
+  Assert.ok(
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should exist"
+  );
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Frecency should be positive.");
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_visits_outside_bookmarked_uri() {
+  info(
+    "*** TEST: Remove some visits outside valid timeframe from a bookmarked URI"
+  );
+
+  info("Add 10 visits for the URI from way in the past.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - 100000 - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+  info("Bookmark the URI.");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: TEST_URI,
+    title: "bookmark title",
+  });
+
+  info("Remove visits using timerange outside the URI's visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 10),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+
+  info("Run a history query and check that all visits still exist.");
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 10);
+  for (let i = 0; i < root.childCount; i++) {
+    let visitTime = root.getChild(i).time;
+    Assert.equal(visitTime, DB_NOW - 100000 - i * 1000);
+  }
+  root.containerOpen = false;
+
+  Assert.ok(
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should exist"
+  );
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("Frecency should be positive.");
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_visits_unbookmarked_uri() {
+  info("*** TEST: Remove some visits from an unbookmarked URI");
+
+  info("Add 10 visits for the URI from now to 9 usecs in the past.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+
+  info("Remove the 5 most recent visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 4),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+
+  info(
+    "Run a history query and check that only the older 5 visits still exist."
+  );
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 5);
+  for (let i = 0; i < root.childCount; i++) {
+    let visitTime = root.getChild(i).time;
+    Assert.equal(visitTime, DB_NOW - i * 1000 - 5000);
+  }
+  root.containerOpen = false;
+
+  Assert.ok(
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should exist"
+  );
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("Frecency should be positive.");
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_visits_bookmarked_uri() {
+  info("*** TEST: Remove some visits from a bookmarked URI");
+
+  info("Add 10 visits for the URI from now to 9 usecs in the past.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+  info("Bookmark the URI.");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: TEST_URI,
+    title: "bookmark title",
+  });
+
+  info("Remove the 5 most recent visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 4),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+
+  info(
+    "Run a history query and check that only the older 5 visits still exist."
+  );
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 5);
+  for (let i = 0; i < root.childCount; i++) {
+    let visitTime = root.getChild(i).time;
+    Assert.equal(visitTime, DB_NOW - i * 1000 - 5000);
+  }
+  root.containerOpen = false;
+
+  Assert.ok(
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should exist"
+  );
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("Frecency should be positive.");
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_all_visits_unbookmarked_uri() {
+  info("*** TEST: Remove all visits from an unbookmarked URI");
+
+  info("Add some visits for the URI.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+
+  info("Remove all visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 10),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should no longer exist in moz_places.");
+  Assert.ok(!page_in_database(TEST_URI.spec));
+
+  info("Run a history query and check that no visits exist.");
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+
+  Assert.equal(
+    false,
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should not exist"
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_all_visits_bookmarked_uri() {
+  info("*** TEST: Remove all visits from a bookmarked URI");
+
+  info("Add some visits for the URI.");
+  let visits = [];
+  for (let i = 0; i < 10; i++) {
+    visits.push({ uri: TEST_URI, visitDate: DB_NOW - i * 1000 });
+  }
+  await PlacesTestUtils.addVisits(visits);
+  info("Bookmark the URI.");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: TEST_URI,
+    title: "bookmark title",
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  let initialFrecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url: TEST_URI }
+  );
+
+  info("Remove all visits.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 10),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+
+  info("Run a history query and check that no visits exist.");
+  let query = PlacesUtils.history.getNewQuery();
+  let opts = PlacesUtils.history.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_VISIT;
+  opts.sortingMode = opts.SORT_BY_DATE_DESCENDING;
+  let root = PlacesUtils.history.executeQuery(query, opts).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+
+  Assert.equal(
+    false,
+    await PlacesUtils.history.hasVisits(TEST_URI),
+    "visit should not exist"
+  );
+
+  info("URI should be bookmarked");
+  Assert.ok(await PlacesUtils.bookmarks.fetch({ url: TEST_URI }));
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("Frecency should be smaller.");
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) < initialFrecency
+  );
+
+  await cleanup();
+});
+
+add_task(async function remove_all_visits_bookmarked_uri() {
+  info(
+    "*** TEST: Remove some visits from a zero frecency URI retains zero frecency"
+  );
+
+  info("Add some visits for the URI.");
+  await PlacesTestUtils.addVisits([
+    {
+      uri: TEST_URI,
+      transition: TRANSITION_FRAMED_LINK,
+      visitDate: DB_NOW - 86400000000000,
+    },
+    { uri: TEST_URI, transition: TRANSITION_FRAMED_LINK, visitDate: DB_NOW },
+  ]);
+
+  info("Remove newer visit.");
+  let filter = {
+    beginDate: new Date(JS_NOW - 10),
+    endDate: new Date(JS_NOW),
+  };
+  await PlacesUtils.history.removeVisitsByFilter(filter);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI should still exist in moz_places.");
+  Assert.ok(page_in_database(TEST_URI.spec));
+  info("Frecency should be zero.");
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await cleanup();
+});
diff --git a/toolkit/components/places/tests/history/test_removeVisitsByFilter.js b/toolkit/components/places/tests/history/test_removeVisitsByFilter.js
new file mode 100644
index 0000000000..5681ab22bc
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_removeVisitsByFilter.js
@@ -0,0 +1,408 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+// Tests for `History.removeVisitsByFilter`, as implemented in History.jsm
+
+"use strict";
+
+add_task(async function test_removeVisitsByFilter() {
+  let referenceDate = new Date(1999, 9, 9, 9, 9);
+
+  // Populate a database with 20 entries, remove a subset of entries,
+  // ensure consistency.
+  let remover = async function (options) {
+    info("Remover with options " + JSON.stringify(options));
+    let SAMPLE_SIZE = options.sampleSize;
+
+    await PlacesUtils.history.clear();
+    await PlacesUtils.bookmarks.eraseEverything();
+
+    // Populate the database.
+    // Create `SAMPLE_SIZE` visits, from the oldest to the newest.
+
+    let bookmarkIndices = new Set(options.bookmarks);
+    let visits = [];
+    let rankingChangePromises = [];
+    let uriDeletePromises = new Map();
+    let getURL = options.url
+      ? i =>
+          "http://mozilla.com/test_browserhistory/test_removeVisitsByFilter/removeme/byurl/" +
+          Math.floor(i / (SAMPLE_SIZE / 5)) +
+          "/"
+      : i =>
+          "http://mozilla.com/test_browserhistory/test_removeVisitsByFilter/removeme/" +
+          i +
+          "/" +
+          Math.random();
+    for (let i = 0; i < SAMPLE_SIZE; ++i) {
+      let spec = getURL(i);
+      let uri = NetUtil.newURI(spec);
+      let jsDate = new Date(Number(referenceDate) + 3600 * 1000 * i);
+      let dbDate = jsDate * 1000;
+      let hasBookmark = bookmarkIndices.has(i);
+      let hasOwnBookmark = hasBookmark;
+      if (!hasOwnBookmark && options.url) {
+        // Also mark as bookmarked if one of the earlier bookmarked items has the same URL.
+        hasBookmark = options.bookmarks
+          .filter(n => n < i)
+          .some(n => visits[n].uri.spec == spec && visits[n].test.hasBookmark);
+      }
+      info("Generating " + uri.spec + ", " + dbDate);
+      let visit = {
+        uri,
+        title: "visit " + i,
+        visitDate: dbDate,
+        test: {
+          // `visitDate`, as a Date
+          jsDate,
+          // `true` if we expect that the visit will be removed
+          toRemove: false,
+          // `true` if `onRow` informed of the removal of this visit
+          announcedByOnRow: false,
+          // `true` if there is a bookmark for this URI, i.e. of the page
+          // should not be entirely removed.
+          hasBookmark,
+        },
+      };
+      visits.push(visit);
+      if (hasOwnBookmark) {
+        info("Adding a bookmark to visit " + i);
+        await PlacesUtils.bookmarks.insert({
+          url: uri,
+          parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+          title: "test bookmark",
+        });
+        info("Bookmark added");
+      }
+    }
+
+    info("Adding visits");
+    await PlacesTestUtils.addVisits(visits);
+
+    info("Preparing filters");
+    let filter = {};
+    let beginIndex = 0;
+    let endIndex = visits.length - 1;
+    if ("begin" in options) {
+      let ms = Number(visits[options.begin].test.jsDate) - 1000;
+      filter.beginDate = new Date(ms);
+      beginIndex = options.begin;
+    }
+    if ("end" in options) {
+      let ms = Number(visits[options.end].test.jsDate) + 1000;
+      filter.endDate = new Date(ms);
+      endIndex = options.end;
+    }
+    if ("limit" in options) {
+      endIndex = beginIndex + options.limit - 1; // -1 because the start index is inclusive.
+      filter.limit = options.limit;
+    }
+    let removedItems = visits.slice(beginIndex);
+    endIndex -= beginIndex;
+    if (options.url) {
+      let rawURL = "";
+      switch (options.url) {
+        case 1:
+          filter.url = new URL(removedItems[0].uri.spec);
+          rawURL = filter.url.href;
+          break;
+        case 2:
+          filter.url = removedItems[0].uri;
+          rawURL = filter.url.spec;
+          break;
+        case 3:
+          filter.url = removedItems[0].uri.spec;
+          rawURL = filter.url;
+          break;
+      }
+      endIndex = Math.min(
+        endIndex,
+        removedItems.findIndex((v, index) => v.uri.spec != rawURL) - 1
+      );
+    }
+    removedItems.splice(endIndex + 1);
+    let remainingItems = visits.filter(v => !removedItems.includes(v));
+    for (let i = 0; i < removedItems.length; i++) {
+      let test = removedItems[i].test;
+      info("Marking visit " + (beginIndex + i) + " as expecting removal");
+      test.toRemove = true;
+      if (
+        test.hasBookmark ||
+        (options.url &&
+          remainingItems.some(v => v.uri.spec == removedItems[i].uri.spec))
+      ) {
+        rankingChangePromises.push(Promise.withResolvers());
+      } else if (!options.url || i == 0) {
+        uriDeletePromises.set(
+          removedItems[i].uri.spec,
+          Promise.withResolvers()
+        );
+      }
+    }
+
+    const placesEventListener = events => {
+      for (const event of events) {
+        switch (event.type) {
+          case "page-title-changed": {
+            this.deferred.reject(
+              "Unexpected page-title-changed event happens on " + event.url
+            );
+            break;
+          }
+          case "history-cleared": {
+            info("history-cleared");
+            this.deferred.reject("Unexpected history-cleared event happens");
+            break;
+          }
+          case "pages-rank-changed": {
+            info("pages-rank-changed");
+            for (const deferred of rankingChangePromises) {
+              deferred.resolve();
+            }
+            break;
+          }
+        }
+      }
+    };
+    PlacesObservers.addListener(
+      ["page-title-changed", "history-cleared", "pages-rank-changed"],
+      placesEventListener
+    );
+
+    let cbarg;
+    if (options.useCallback) {
+      info("Setting up callback");
+      cbarg = [
+        info => {
+          for (let visit of visits) {
+            info("Comparing " + info.date + " and " + visit.test.jsDate);
+            if (Math.abs(visit.test.jsDate - info.date) < 100) {
+              // Assume rounding errors
+              Assert.ok(
+                !visit.test.announcedByOnRow,
+                "This is the first time we announce the removal of this visit"
+              );
+              Assert.ok(
+                visit.test.toRemove,
+                "This is a visit we intended to remove"
+              );
+              visit.test.announcedByOnRow = true;
+              return;
+            }
+          }
+          Assert.ok(false, "Could not find the visit we attempt to remove");
+        },
+      ];
+    } else {
+      info("No callback");
+      cbarg = [];
+    }
+    let result = await PlacesUtils.history.removeVisitsByFilter(
+      filter,
+      ...cbarg
+    );
+
+    Assert.ok(result, "Removal succeeded");
+
+    // Make sure that we have eliminated exactly the entries we expected
+    // to eliminate.
+    for (let i = 0; i < visits.length; ++i) {
+      let visit = visits[i];
+      info("Controlling the results on visit " + i);
+      let remainingVisitsForURI = remainingItems.filter(
+        v => visit.uri.spec == v.uri.spec
+      ).length;
+      Assert.equal(
+        visits_in_database(visit.uri),
+        remainingVisitsForURI,
+        "Visit is still present iff expected"
+      );
+      if (options.useCallback) {
+        Assert.equal(
+          visit.test.toRemove,
+          visit.test.announcedByOnRow,
+          "Visit removal has been announced by onResult iff expected"
+        );
+      }
+      if (visit.test.hasBookmark || remainingVisitsForURI) {
+        Assert.notEqual(
+          page_in_database(visit.uri),
+          0,
+          "The page should still appear in the db"
+        );
+      } else {
+        Assert.equal(
+          page_in_database(visit.uri),
+          0,
+          "The page should have been removed from the db"
+        );
+      }
+    }
+
+    // Make sure that the observer has been called wherever applicable.
+    info("Checking URI delete promises.");
+    await Promise.all(Array.from(uriDeletePromises.values()));
+    info("Checking frecency change promises.");
+    await Promise.all(rankingChangePromises);
+    PlacesObservers.removeListener(
+      ["page-title-changed", "history-cleared", "pages-rank-changed"],
+      placesEventListener
+    );
+  };
+
+  let size = 20;
+  for (let range of [
+    { begin: 0 },
+    { end: 19 },
+    { begin: 0, end: 10 },
+    { begin: 3, end: 4 },
+    { begin: 5, end: 8, limit: 2 },
+    { begin: 10, end: 18, limit: 5 },
+  ]) {
+    for (let bookmarks of [[], [5, 6]]) {
+      let options = {
+        sampleSize: size,
+        bookmarks,
+      };
+      if ("begin" in range) {
+        options.begin = range.begin;
+      }
+      if ("end" in range) {
+        options.end = range.end;
+      }
+      if ("limit" in range) {
+        options.limit = range.limit;
+      }
+      await remover(options);
+      options.url = 1;
+      await remover(options);
+      options.url = 2;
+      await remover(options);
+      options.url = 3;
+      await remover(options);
+    }
+  }
+  await PlacesUtils.history.clear();
+});
+
+// Test the various error cases
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter(),
+    /TypeError: Expected a filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter("obviously, not a filter"),
+    /TypeError: Expected a filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({}),
+    /TypeError: Expected a non-empty filter/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ beginDate: "now" }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ beginDate: Date.now() }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeVisitsByFilter({ beginDate: new Date(NaN) }),
+    /TypeError: Expected a valid Date/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeVisitsByFilter(
+        { beginDate: new Date() },
+        "obviously, not a callback"
+      ),
+    /TypeError: Invalid function/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeVisitsByFilter({
+        beginDate: new Date(1000),
+        endDate: new Date(0),
+      }),
+    /TypeError: `beginDate` should be at least as old/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ limit: {} }),
+    /Expected a non-zero positive integer as a limit/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ limit: -1 }),
+    /Expected a non-zero positive integer as a limit/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ limit: 0.1 }),
+    /Expected a non-zero positive integer as a limit/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ limit: Infinity }),
+    /Expected a non-zero positive integer as a limit/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ url: {} }),
+    /Expected a valid URL for `url`/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ url: 0 }),
+    /Expected a valid URL for `url`/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeVisitsByFilter({
+        beginDate: new Date(1000),
+        endDate: new Date(0),
+      }),
+    /TypeError: `beginDate` should be at least as old/
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.removeVisitsByFilter({
+        beginDate: new Date(1000),
+        endDate: new Date(0),
+      }),
+    /TypeError: `beginDate` should be at least as old/
+  );
+  Assert.throws(
+    () => PlacesUtils.history.removeVisitsByFilter({ transition: -1 }),
+    /TypeError: `transition` should be valid/
+  );
+});
+
+add_task(async function test_orphans() {
+  let uri = NetUtil.newURI("http://moz.org/");
+  await PlacesTestUtils.addVisits({ uri });
+
+  PlacesUtils.favicons.setAndFetchFaviconForPage(
+    uri,
+    SMALLPNG_DATA_URI,
+    true,
+    PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+    null,
+    Services.scriptSecurityManager.getSystemPrincipal()
+  );
+  await PlacesUtils.history.update({
+    url: uri,
+    annotations: new Map([["test", "restval"]]),
+  });
+
+  await PlacesUtils.history.removeVisitsByFilter({
+    beginDate: new Date(1999, 9, 9, 9, 9),
+    endDate: new Date(),
+  });
+  Assert.ok(
+    !(await PlacesTestUtils.isPageInDB(uri)),
+    "Page should have been removed"
+  );
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`SELECT (SELECT count(*) FROM moz_annos) +
+                                      (SELECT count(*) FROM moz_icons) +
+                                      (SELECT count(*) FROM moz_pages_w_icons) +
+                                      (SELECT count(*) FROM moz_icons_to_pages) AS count`);
+  Assert.equal(rows[0].getResultByName("count"), 0, "Should not find orphans");
+});
diff --git a/toolkit/components/places/tests/history/test_sameUri_titleChanged.js b/toolkit/components/places/tests/history/test_sameUri_titleChanged.js
new file mode 100644
index 0000000000..016e5402fa
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_sameUri_titleChanged.js
@@ -0,0 +1,48 @@
+// Test that repeated additions of the same URI to history, properly
+// update from_visit and notify titleChanged.
+
+add_task(async function test() {
+  let uri = "http://test.com/";
+
+  const promiseTitleChangedNotifications =
+    PlacesTestUtils.waitForNotification("page-title-changed");
+
+  // This repeats the url on purpose, don't merge it into a single place entry.
+  await PlacesTestUtils.addVisits([
+    { uri, title: "test" },
+    { uri, referrer: uri, title: "test2" },
+  ]);
+
+  const events = await promiseTitleChangedNotifications;
+  Assert.equal(events.length, 1, "Right number of title changed notified");
+  Assert.equal(events[0].url, uri, "Should notify the proper url");
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let query = PlacesUtils.history.getNewQuery();
+  query.uri = NetUtil.newURI(uri);
+  options.resultType = options.RESULTS_AS_VISIT;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(root.childCount, 2);
+
+  let child = root.getChild(0);
+  Assert.equal(
+    child.visitType,
+    TRANSITION_LINK,
+    "Visit type should be TRANSITION_LINK"
+  );
+  Assert.equal(child.visitId, 1, "Visit ID should be 1");
+  Assert.equal(child.title, "test2", "Should have the correct title");
+
+  child = root.getChild(1);
+  Assert.equal(
+    child.visitType,
+    TRANSITION_LINK,
+    "Visit type should be TRANSITION_LINK"
+  );
+  Assert.equal(child.visitId, 2, "Visit ID should be 2");
+  Assert.equal(child.title, "test2", "Should have the correct title");
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/history/test_update.js b/toolkit/components/places/tests/history/test_update.js
new file mode 100644
index 0000000000..d7beafd368
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_update.js
@@ -0,0 +1,700 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests for `History.update` as implemented in History.jsm
+
+"use strict";
+
+add_task(async function test_error_cases() {
+  Assert.throws(
+    () => PlacesUtils.history.update("not an object"),
+    /Error: PageInfo: Input should be a valid object/,
+    "passing a string as pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.update(null),
+    /Error: PageInfo: Input should be/,
+    "passing a null as pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        description: "Test description",
+      }),
+    /Error: PageInfo: The following properties were expected: url, guid/,
+    "not included a url or a guid should throw"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.update({ url: "not a valid url string" }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing an invalid url should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        description: 123,
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a non-string description in pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        guid: "invalid guid",
+        description: "Test description",
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a invalid guid in pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        previewImageURL: "not a valid url string",
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing an invlid preview image url in pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () => {
+      let imageName = "a-very-long-string".repeat(10000);
+      let previewImageURL = `http://valid.uri.com/${imageName}.png`;
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        previewImageURL,
+      });
+    },
+    /Error: PageInfo: Invalid value for property/,
+    "passing an oversized previewImageURL in pageInfo should throw an Error"
+  );
+  Assert.throws(
+    () => PlacesUtils.history.update({ url: "http://valid.uri.com" }),
+    /TypeError: pageInfo object must at least/,
+    "passing a pageInfo with neither description, previewImageURL, nor annotations should throw a TypeError"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        annotations: "asd",
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a pageInfo with incorrect annotations type should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        annotations: new Map(),
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a pageInfo with an empty annotations type should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        annotations: new Map([[1234, "value"]]),
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a pageInfo with an invalid key type should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        annotations: new Map([["test", ["myarray"]]]),
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a pageInfo with an invalid key type should throw an Error"
+  );
+  Assert.throws(
+    () =>
+      PlacesUtils.history.update({
+        url: "http://valid.uri.com",
+        annotations: new Map([["test", { anno: "value" }]]),
+      }),
+    /Error: PageInfo: Invalid value for property/,
+    "passing a pageInfo with an invalid key type should throw an Error"
+  );
+});
+
+add_task(async function test_description_change_saved() {
+  await PlacesUtils.history.clear();
+
+  let TEST_URL = "http://mozilla.org/test_description_change_saved";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(await PlacesTestUtils.isPageInDB(TEST_URL));
+
+  let description = "Test description";
+  await PlacesUtils.history.update({ url: TEST_URL, description });
+  let descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    { url: TEST_URL }
+  );
+  Assert.equal(
+    description,
+    descriptionInDB,
+    "description should be updated via URL as expected"
+  );
+
+  description = "";
+  await PlacesUtils.history.update({ url: TEST_URL, description });
+  descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    { url: TEST_URL }
+  );
+  Assert.strictEqual(
+    null,
+    descriptionInDB,
+    "an empty description should set it to null in the database"
+  );
+
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: TEST_URL,
+  });
+  description = "Test description";
+  await PlacesUtils.history.update({ url: TEST_URL, guid, description });
+  descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    { url: TEST_URL }
+  );
+  Assert.equal(
+    description,
+    descriptionInDB,
+    "description should be updated via GUID as expected"
+  );
+
+  description = "Test descipriton".repeat(1000);
+  await PlacesUtils.history.update({ url: TEST_URL, description });
+  descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    { url: TEST_URL }
+  );
+  Assert.ok(
+    !!descriptionInDB.length < description.length,
+    "a long description should be truncated"
+  );
+
+  description = null;
+  await PlacesUtils.history.update({ url: TEST_URL, description });
+  descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    { url: TEST_URL }
+  );
+  Assert.strictEqual(
+    description,
+    descriptionInDB,
+    "a null description should set it to null in the database"
+  );
+});
+
+add_task(async function test_siteName_change_saved() {
+  await PlacesUtils.history.clear();
+
+  let TEST_URL = "http://mozilla.org/test_siteName_change_saved";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(await PlacesTestUtils.isPageInDB(TEST_URL));
+
+  let siteName = "Test site name";
+  await PlacesUtils.history.update({ url: TEST_URL, siteName });
+  let siteNameInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "site_name",
+    { url: TEST_URL }
+  );
+  Assert.equal(
+    siteName,
+    siteNameInDB,
+    "siteName should be updated via URL as expected"
+  );
+
+  siteName = "";
+  await PlacesUtils.history.update({ url: TEST_URL, siteName });
+  siteNameInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "site_name",
+    { url: TEST_URL }
+  );
+  Assert.strictEqual(
+    null,
+    siteNameInDB,
+    "an empty siteName should set it to null in the database"
+  );
+
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: TEST_URL,
+  });
+  siteName = "Test site name";
+  await PlacesUtils.history.update({ url: TEST_URL, guid, siteName });
+  siteNameInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "site_name",
+    { url: TEST_URL }
+  );
+  Assert.equal(
+    siteName,
+    siteNameInDB,
+    "siteName should be updated via GUID as expected"
+  );
+
+  siteName = "Test site name".repeat(1000);
+  await PlacesUtils.history.update({ url: TEST_URL, siteName });
+  siteNameInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "site_name",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.ok(
+    !!siteNameInDB.length < siteName.length,
+    "a long siteName should be truncated"
+  );
+
+  siteName = null;
+  await PlacesUtils.history.update({ url: TEST_URL, siteName });
+  siteNameInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "site_name",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.strictEqual(
+    siteName,
+    siteNameInDB,
+    "a null siteName should set it to null in the database"
+  );
+});
+
+add_task(async function test_previewImageURL_change_saved() {
+  await PlacesUtils.history.clear();
+
+  let TEST_URL = "http://mozilla.org/test_previewImageURL_change_saved";
+  let IMAGE_URL = "http://mozilla.org/test_preview_image.png";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(await PlacesTestUtils.isPageInDB(TEST_URL));
+
+  let previewImageURL = IMAGE_URL;
+  await PlacesUtils.history.update({ url: TEST_URL, previewImageURL });
+  let previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(
+    previewImageURL,
+    previewImageURLInDB,
+    "previewImageURL should be updated via URL as expected"
+  );
+
+  previewImageURL = null;
+  await PlacesUtils.history.update({ url: TEST_URL, previewImageURL });
+  previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.strictEqual(
+    null,
+    previewImageURLInDB,
+    "a null previewImageURL should set it to null in the database"
+  );
+
+  let guid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: TEST_URL,
+  });
+  previewImageURL = IMAGE_URL;
+  await PlacesUtils.history.update({ guid, previewImageURL });
+  previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(
+    previewImageURL,
+    previewImageURLInDB,
+    "previewImageURL should be updated via GUID as expected"
+  );
+
+  previewImageURL = "";
+  await PlacesUtils.history.update({ url: TEST_URL, previewImageURL });
+  previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.strictEqual(
+    null,
+    previewImageURLInDB,
+    "an empty previewImageURL should set it to null in the database"
+  );
+});
+
+add_task(async function test_change_description_and_preview_saved() {
+  await PlacesUtils.history.clear();
+
+  let TEST_URL = "http://mozilla.org/test_change_both_saved";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(await PlacesTestUtils.isPageInDB(TEST_URL));
+
+  let description = "Test description";
+  let previewImageURL = "http://mozilla.org/test_preview_image.png";
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    description,
+    previewImageURL,
+  });
+  let descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    {
+      url: TEST_URL,
+    }
+  );
+  let previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(
+    description,
+    descriptionInDB,
+    "description should be updated via URL as expected"
+  );
+  Assert.equal(
+    previewImageURL,
+    previewImageURLInDB,
+    "previewImageURL should be updated via URL as expected"
+  );
+
+  // Update description should not touch other fields
+  description = null;
+  await PlacesUtils.history.update({ url: TEST_URL, description });
+  descriptionInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "description",
+    {
+      url: TEST_URL,
+    }
+  );
+  previewImageURLInDB = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "preview_image_url",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.strictEqual(
+    description,
+    descriptionInDB,
+    "description should be updated via URL as expected"
+  );
+  Assert.equal(
+    previewImageURL,
+    previewImageURLInDB,
+    "previewImageURL should not be updated"
+  );
+});
+
+/**
+ * Gets annotation information from the database for the specified URL and
+ * annotation name.
+ *
+ * @param {String} pageUrl The URL to search for.
+ * @param {String} annoName The name of the annotation to search for.
+ * @return {Array} An array of objects containing the annotations found.
+ */
+async function getAnnotationInfoFromDB(pageUrl, annoName) {
+  let db = await PlacesUtils.promiseDBConnection();
+
+  let rows = await db.execute(
+    `
+    SELECT a.content, a.flags, a.expiration, a.type FROM moz_anno_attributes n
+    JOIN moz_annos a ON n.id = a.anno_attribute_id
+    JOIN moz_places h ON h.id = a.place_id
+    WHERE h.url_hash = hash(:pageUrl) AND h.url = :pageUrl
+      AND n.name = :annoName
+  `,
+    { annoName, pageUrl }
+  );
+
+  let result = rows.map(row => {
+    return {
+      content: row.getResultByName("content"),
+      flags: row.getResultByName("flags"),
+      expiration: row.getResultByName("expiration"),
+      type: row.getResultByName("type"),
+    };
+  });
+
+  return result;
+}
+
+add_task(async function test_simple_change_annotations() {
+  await PlacesUtils.history.clear();
+
+  const TEST_URL = "http://mozilla.org/test_change_both_saved";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL),
+    "Should have inserted the page into the database."
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/annotation", "testContent"]]),
+  });
+
+  let pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    1,
+    "Should have one annotation for the page"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    "testContent",
+    "Should have the correct annotation"
+  );
+
+  let annotationInfo = await getAnnotationInfoFromDB(
+    TEST_URL,
+    "test/annotation"
+  );
+  Assert.deepEqual(
+    {
+      content: "testContent",
+      flags: 0,
+      type: PlacesUtils.history.ANNOTATION_TYPE_STRING,
+      expiration: PlacesUtils.history.ANNOTATION_EXPIRE_NEVER,
+    },
+    annotationInfo[0],
+    "Should have stored the correct annotation data in the db"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/annotation2", "testAnno"]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    2,
+    "Should have two annotations for the page"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    "testContent",
+    "Should have the correct value for the first annotation"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    "testAnno",
+    "Should have the correct value for the second annotation"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/annotation", 1234]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    2,
+    "Should still have two annotations for the page"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    1234,
+    "Should have the updated the first annotation value"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    "testAnno",
+    "Should have kept the value for the second annotation"
+  );
+
+  annotationInfo = await getAnnotationInfoFromDB(TEST_URL, "test/annotation");
+  Assert.deepEqual(
+    {
+      content: 1234,
+      flags: 0,
+      type: PlacesUtils.history.ANNOTATION_TYPE_INT64,
+      expiration: PlacesUtils.history.ANNOTATION_EXPIRE_NEVER,
+    },
+    annotationInfo[0],
+    "Should have updated the annotation data in the db"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/annotation", null]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    1,
+    "Should have removed only the first annotation"
+  );
+  Assert.strictEqual(
+    pageInfo.annotations.get("test/annotation"),
+    undefined,
+    "Should have removed only the first annotation"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    "testAnno",
+    "Should have kept the value for the second annotation"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([["test/annotation2", null]]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(pageInfo.annotations.size, 0, "Should have no annotations left");
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`
+    SELECT * FROM moz_annos
+  `);
+  Assert.equal(rows.length, 0, "Should be no annotations left in the db");
+});
+
+add_task(async function test_change_multiple_annotations() {
+  await PlacesUtils.history.clear();
+
+  const TEST_URL = "http://mozilla.org/test_change_both_saved";
+  await PlacesTestUtils.addVisits(TEST_URL);
+  Assert.ok(
+    await PlacesTestUtils.isPageInDB(TEST_URL),
+    "Should have inserted the page into the database."
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([
+      ["test/annotation", "testContent"],
+      ["test/annotation2", "testAnno"],
+    ]),
+  });
+
+  let pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    2,
+    "Should have inserted the two annotations for the page."
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    "testContent",
+    "Should have the correct value for the first annotation"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    "testAnno",
+    "Should have the correct value for the second annotation"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([
+      ["test/annotation", 123456],
+      ["test/annotation2", 135246],
+    ]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.size,
+    2,
+    "Should have two annotations for the page"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation"),
+    123456,
+    "Should have the correct value for the first annotation"
+  );
+  Assert.equal(
+    pageInfo.annotations.get("test/annotation2"),
+    135246,
+    "Should have the correct value for the second annotation"
+  );
+
+  await PlacesUtils.history.update({
+    url: TEST_URL,
+    annotations: new Map([
+      ["test/annotation", null],
+      ["test/annotation2", null],
+    ]),
+  });
+
+  pageInfo = await PlacesUtils.history.fetch(TEST_URL, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(pageInfo.annotations.size, 0, "Should have no annotations left");
+});
+
+add_task(async function test_annotations_nonexisting_page() {
+  info("Adding annotations to a non existing page should be silent");
+  await PlacesUtils.history.update({
+    url: "http://nonexisting.moz/",
+    annotations: new Map([["test/annotation", null]]),
+  });
+});
+
+add_task(async function test_annotations_nonexisting_page() {
+  info("Adding annotations to a non existing page should be silent");
+  await PlacesUtils.history.update({
+    url: "http://nonexisting.moz/",
+    annotations: new Map([["test/annotation", null]]),
+  });
+});
diff --git a/toolkit/components/places/tests/history/test_updatePlaces_embed.js b/toolkit/components/places/tests/history/test_updatePlaces_embed.js
new file mode 100644
index 0000000000..a2831f2f58
--- /dev/null
+++ b/toolkit/components/places/tests/history/test_updatePlaces_embed.js
@@ -0,0 +1,81 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that updatePlaces properly handled callbacks for embed visits.
+
+"use strict";
+
+XPCOMUtils.defineLazyServiceGetter(
+  this,
+  "asyncHistory",
+  "@mozilla.org/browser/history;1",
+  "mozIAsyncHistory"
+);
+
+add_task(async function test_embed_visit() {
+  let place = {
+    uri: NetUtil.newURI("http://places.test/"),
+    visits: [
+      {
+        transitionType: PlacesUtils.history.TRANSITIONS.EMBED,
+        visitDate: PlacesUtils.toPRTime(new Date()),
+      },
+    ],
+  };
+  let errors = 0;
+  let results = 0;
+  let updated = await new Promise(resolve => {
+    asyncHistory.updatePlaces(place, {
+      ignoreErrors: true,
+      ignoreResults: true,
+      handleError(aResultCode, aPlace) {
+        errors++;
+      },
+      handleResult(aPlace) {
+        results++;
+      },
+      handleCompletion(resultCount) {
+        resolve(resultCount);
+      },
+    });
+  });
+  Assert.equal(errors, 0, "There should be no error callback");
+  Assert.equal(results, 0, "There should be no result callback");
+  Assert.equal(updated, 1, "The visit should have been added");
+});
+
+add_task(async function test_misc_visits() {
+  let place = {
+    uri: NetUtil.newURI("http://places.test/"),
+    visits: [
+      {
+        transitionType: PlacesUtils.history.TRANSITIONS.EMBED,
+        visitDate: PlacesUtils.toPRTime(new Date()),
+      },
+      {
+        transitionType: PlacesUtils.history.TRANSITIONS.LINK,
+        visitDate: PlacesUtils.toPRTime(new Date()),
+      },
+    ],
+  };
+  let errors = 0;
+  let results = 0;
+  let updated = await new Promise(resolve => {
+    asyncHistory.updatePlaces(place, {
+      ignoreErrors: true,
+      ignoreResults: true,
+      handleError(aResultCode, aPlace) {
+        errors++;
+      },
+      handleResult(aPlace) {
+        results++;
+      },
+      handleCompletion(resultCount) {
+        resolve(resultCount);
+      },
+    });
+  });
+  Assert.equal(errors, 0, "There should be no error callback");
+  Assert.equal(results, 0, "There should be no result callback");
+  Assert.equal(updated, 2, "The visit should have been added");
+});
diff --git a/toolkit/components/places/tests/history/xpcshell.toml b/toolkit/components/places/tests/history/xpcshell.toml
new file mode 100644
index 0000000000..8728743f1a
--- /dev/null
+++ b/toolkit/components/places/tests/history/xpcshell.toml
@@ -0,0 +1,36 @@
+[DEFAULT]
+head = "head_history.js"
+
+["test_async_history_api.js"]
+
+["test_bookmark_unhide.js"]
+
+["test_fetch.js"]
+
+["test_fetchAnnotatedPages.js"]
+
+["test_fetchMany.js"]
+
+["test_hasVisits.js"]
+
+["test_insert.js"]
+
+["test_insertMany.js"]
+
+["test_insert_null_title.js"]
+
+["test_remove.js"]
+
+["test_removeByFilter.js"]
+
+["test_removeMany.js"]
+
+["test_removeVisits.js"]
+
+["test_removeVisitsByFilter.js"]
+
+["test_sameUri_titleChanged.js"]
+
+["test_update.js"]
+
+["test_updatePlaces_embed.js"]
diff --git a/toolkit/components/places/tests/legacy/head_legacy.js b/toolkit/components/places/tests/legacy/head_legacy.js
new file mode 100644
index 0000000000..06e7fda560
--- /dev/null
+++ b/toolkit/components/places/tests/legacy/head_legacy.js
@@ -0,0 +1,14 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
diff --git a/toolkit/components/places/tests/legacy/test_bookmarks.js b/toolkit/components/places/tests/legacy/test_bookmarks.js
new file mode 100644
index 0000000000..526541f749
--- /dev/null
+++ b/toolkit/components/places/tests/legacy/test_bookmarks.js
@@ -0,0 +1,519 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var bs = PlacesUtils.bookmarks;
+var hs = PlacesUtils.history;
+var os = PlacesUtils.observers;
+
+var bookmarksObserver = {
+  handlePlacesEvents(events) {
+    Assert.equal(events.length, 1);
+    let event = events[0];
+    switch (event.type) {
+      case "bookmark-added":
+        bookmarksObserver._itemAddedId = event.id;
+        bookmarksObserver._itemAddedParent = event.parentId;
+        bookmarksObserver._itemAddedIndex = event.index;
+        bookmarksObserver._itemAddedURI = event.url
+          ? Services.io.newURI(event.url)
+          : null;
+        bookmarksObserver._itemAddedTitle = event.title;
+
+        // Ensure that we've created a guid for this item.
+        let stmt = DBConn().createStatement(
+          `SELECT guid
+           FROM moz_bookmarks
+           WHERE id = :item_id`
+        );
+        stmt.params.item_id = event.id;
+        Assert.ok(stmt.executeStep());
+        Assert.ok(!stmt.getIsNull(0));
+        do_check_valid_places_guid(stmt.row.guid);
+        Assert.equal(stmt.row.guid, event.guid);
+        stmt.finalize();
+        break;
+      case "bookmark-removed":
+        bookmarksObserver._itemRemovedId = event.id;
+        bookmarksObserver._itemRemovedFolder = event.parentId;
+        bookmarksObserver._itemRemovedIndex = event.index;
+        break;
+      case "bookmark-title-changed":
+        bookmarksObserver._itemTitleChangedId = event.id;
+        bookmarksObserver._itemTitleChangedTitle = event.title;
+        break;
+    }
+  },
+};
+
+var root;
+// Index at which items should begin.
+var bmStartIndex = 0;
+
+add_task(async function setup() {
+  // Get bookmarks menu folder id.
+  root = await PlacesTestUtils.promiseItemId(PlacesUtils.bookmarks.menuGuid);
+});
+
+add_task(async function test_bookmarks() {
+  os.addListener(
+    ["bookmark-added", "bookmark-removed", "bookmark-title-changed"],
+    bookmarksObserver.handlePlacesEvents
+  );
+
+  // test special folders
+  Assert.ok(bs.tagsFolder > 0);
+
+  // create a folder to hold all the tests
+  // this makes the tests more tolerant of changes to default_places.html
+  let testRoot = bs.createFolder(
+    root,
+    "places bookmarks xpcshell tests",
+    bs.DEFAULT_INDEX
+  );
+  let testRootGuid = await PlacesTestUtils.promiseItemGuid(testRoot);
+  Assert.equal(bookmarksObserver._itemAddedId, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedParent, root);
+  Assert.equal(bookmarksObserver._itemAddedIndex, bmStartIndex);
+  Assert.equal(bookmarksObserver._itemAddedURI, null);
+  let testStartIndex = 0;
+
+  // insert a bookmark.
+  // the time before we insert, in microseconds
+  let beforeInsert = Date.now() * 1000;
+  Assert.ok(beforeInsert > 0);
+
+  let newId = bs.insertBookmark(
+    testRoot,
+    uri("http://google.com/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId);
+  Assert.equal(bookmarksObserver._itemAddedParent, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedIndex, testStartIndex);
+  Assert.ok(bookmarksObserver._itemAddedURI.equals(uri("http://google.com/")));
+
+  // after just inserting, modified should not be set
+  let lastModified = PlacesUtils.toPRTime(
+    (
+      await PlacesUtils.bookmarks.fetch(
+        await PlacesTestUtils.promiseItemGuid(newId)
+      )
+    ).lastModified
+  );
+
+  // The time before we set the title, in microseconds.
+  let beforeSetTitle = Date.now() * 1000;
+  Assert.ok(beforeSetTitle >= beforeInsert);
+
+  // Workaround possible VM timers issues moving lastModified and dateAdded
+  // to the past.
+  lastModified -= 1000;
+  bs.setItemLastModified(newId, lastModified);
+
+  // set bookmark title
+  bs.setItemTitle(newId, "Google");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "Google");
+
+  // check lastModified after we set the title
+  let lastModified2 = PlacesUtils.toPRTime(
+    (
+      await PlacesUtils.bookmarks.fetch(
+        await PlacesTestUtils.promiseItemGuid(newId)
+      )
+    ).lastModified
+  );
+  info("test setItemTitle");
+  info("beforeSetTitle = " + beforeSetTitle);
+  info("lastModified = " + lastModified);
+  info("lastModified2 = " + lastModified2);
+  Assert.ok(is_time_ordered(lastModified, lastModified2));
+
+  // get item title
+  let title = bs.getItemTitle(newId);
+  Assert.equal(title, "Google");
+
+  // get item title bad input
+  try {
+    bs.getItemTitle(-3);
+    do_throw("getItemTitle accepted bad input");
+  } catch (ex) {}
+
+  // create a folder at a specific index
+  let workFolder = bs.createFolder(testRoot, "Work", 0);
+  Assert.equal(bookmarksObserver._itemAddedId, workFolder);
+  Assert.equal(bookmarksObserver._itemAddedParent, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 0);
+  Assert.equal(bookmarksObserver._itemAddedURI, null);
+
+  Assert.equal(bs.getItemTitle(workFolder), "Work");
+  bs.setItemTitle(workFolder, "Work #");
+  Assert.equal(bs.getItemTitle(workFolder), "Work #");
+
+  // add item into subfolder, specifying index
+  let newId2 = bs.insertBookmark(
+    workFolder,
+    uri("http://developer.mozilla.org/"),
+    0,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId2);
+  Assert.equal(bookmarksObserver._itemAddedParent, workFolder);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 0);
+
+  // change item
+  bs.setItemTitle(newId2, "DevMo");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId2);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "DevMo");
+
+  // insert item into subfolder
+  let newId3 = bs.insertBookmark(
+    workFolder,
+    uri("http://msdn.microsoft.com/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId3);
+  Assert.equal(bookmarksObserver._itemAddedParent, workFolder);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 1);
+
+  // change item
+  bs.setItemTitle(newId3, "MSDN");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId3);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "MSDN");
+
+  // remove item
+  bs.removeItem(newId2);
+  Assert.equal(bookmarksObserver._itemRemovedId, newId2);
+  Assert.equal(bookmarksObserver._itemRemovedFolder, workFolder);
+  Assert.equal(bookmarksObserver._itemRemovedIndex, 0);
+
+  // insert item into subfolder
+  let newId4 = bs.insertBookmark(
+    workFolder,
+    uri("http://developer.mozilla.org/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId4);
+  Assert.equal(bookmarksObserver._itemAddedParent, workFolder);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 1);
+
+  // create folder
+  let homeFolder = bs.createFolder(testRoot, "Home", bs.DEFAULT_INDEX);
+  Assert.equal(bookmarksObserver._itemAddedId, homeFolder);
+  Assert.equal(bookmarksObserver._itemAddedParent, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 2);
+
+  // insert item
+  let newId5 = bs.insertBookmark(
+    homeFolder,
+    uri("http://espn.com/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId5);
+  Assert.equal(bookmarksObserver._itemAddedParent, homeFolder);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 0);
+
+  // change item
+  bs.setItemTitle(newId5, "ESPN");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId5);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "ESPN");
+
+  // insert query item
+  let uri6 = uri(
+    "place:domain=google.com&type=" +
+      Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY
+  );
+  let newId6 = bs.insertBookmark(testRoot, uri6, bs.DEFAULT_INDEX, "");
+  Assert.equal(bookmarksObserver._itemAddedParent, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 3);
+
+  // change item
+  bs.setItemTitle(newId6, "Google Sites");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId6);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "Google Sites");
+
+  // test bookmark id in query output
+  try {
+    let options = hs.getNewQueryOptions();
+    let query = hs.getNewQuery();
+    query.setParents([testRootGuid]);
+    let result = hs.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    info("bookmark itemId test: CC = " + cc);
+    Assert.ok(cc > 0);
+    for (let i = 0; i < cc; ++i) {
+      let node = rootNode.getChild(i);
+      if (
+        node.type == node.RESULT_TYPE_FOLDER ||
+        node.type == node.RESULT_TYPE_URI ||
+        node.type == node.RESULT_TYPE_SEPARATOR ||
+        node.type == node.RESULT_TYPE_QUERY
+      ) {
+        Assert.ok(node.itemId > 0);
+      } else {
+        Assert.equal(node.itemId, -1);
+      }
+    }
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("bookmarks query: " + ex);
+  }
+
+  // test that multiple bookmarks with same URI show up right in bookmark
+  // folder queries, todo: also to do for complex folder queries
+  try {
+    // test uri
+    let mURI = uri("http://multiple.uris.in.query");
+
+    let testFolder = bs.createFolder(testRoot, "test Folder", bs.DEFAULT_INDEX);
+    let testFolderGuid = await PlacesTestUtils.promiseItemGuid(testFolder);
+    // add 2 bookmarks
+    bs.insertBookmark(testFolder, mURI, bs.DEFAULT_INDEX, "title 1");
+    bs.insertBookmark(testFolder, mURI, bs.DEFAULT_INDEX, "title 2");
+
+    // query
+    let options = hs.getNewQueryOptions();
+    let query = hs.getNewQuery();
+    query.setParents([testFolderGuid]);
+    let result = hs.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.equal(cc, 2);
+    Assert.equal(rootNode.getChild(0).title, "title 1");
+    Assert.equal(rootNode.getChild(1).title, "title 2");
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("bookmarks query: " + ex);
+  }
+
+  // test change bookmark uri
+  let newId10 = bs.insertBookmark(
+    testRoot,
+    uri("http://foo10.com/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+
+  // Workaround possible VM timers issues moving lastModified and dateAdded
+  // to the past.
+  lastModified -= 1000;
+  bs.setItemLastModified(newId10, lastModified);
+
+  // insert a bookmark with title ZZZXXXYYY and then search for it.
+  // this test confirms that we can find bookmarks that we haven't visited
+  // (which are "hidden") and that we can find by title.
+  // see bug #369887 for more details
+  let newId13 = bs.insertBookmark(
+    testRoot,
+    uri("http://foobarcheese.com/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  Assert.equal(bookmarksObserver._itemAddedId, newId13);
+  Assert.equal(bookmarksObserver._itemAddedParent, testRoot);
+  Assert.equal(bookmarksObserver._itemAddedIndex, 6);
+
+  // set bookmark title
+  bs.setItemTitle(newId13, "ZZZXXXYYY");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId13);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, "ZZZXXXYYY");
+
+  // test search on bookmark title ZZZXXXYYY
+  try {
+    let options = hs.getNewQueryOptions();
+    options.excludeQueries = 1;
+    options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+    let query = hs.getNewQuery();
+    query.searchTerms = "ZZZXXXYYY";
+    let result = hs.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.equal(cc, 1);
+    let node = rootNode.getChild(0);
+    Assert.equal(node.title, "ZZZXXXYYY");
+    Assert.ok(node.itemId > 0);
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("bookmarks query: " + ex);
+  }
+
+  // test dateAdded and lastModified properties
+  // for a search query
+  try {
+    let options = hs.getNewQueryOptions();
+    options.excludeQueries = 1;
+    options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+    let query = hs.getNewQuery();
+    query.searchTerms = "ZZZXXXYYY";
+    let result = hs.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.equal(cc, 1);
+    let node = rootNode.getChild(0);
+
+    Assert.equal(typeof node.dateAdded, "number");
+    Assert.ok(node.dateAdded > 0);
+
+    Assert.equal(typeof node.lastModified, "number");
+    Assert.ok(node.lastModified > 0);
+
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("bookmarks query: " + ex);
+  }
+
+  // test dateAdded and lastModified properties
+  // for a folder query
+  try {
+    let options = hs.getNewQueryOptions();
+    let query = hs.getNewQuery();
+    query.setParents([testRootGuid]);
+    let result = hs.executeQuery(query, options);
+    let rootNode = result.root;
+    rootNode.containerOpen = true;
+    let cc = rootNode.childCount;
+    Assert.ok(cc > 0);
+    for (let i = 0; i < cc; i++) {
+      let node = rootNode.getChild(i);
+
+      if (node.type == node.RESULT_TYPE_URI) {
+        Assert.equal(typeof node.dateAdded, "number");
+        Assert.ok(node.dateAdded > 0);
+
+        Assert.equal(typeof node.lastModified, "number");
+        Assert.ok(node.lastModified > 0);
+        break;
+      }
+    }
+    rootNode.containerOpen = false;
+  } catch (ex) {
+    do_throw("bookmarks query: " + ex);
+  }
+
+  // check setItemLastModified()
+  let newId14 = bs.insertBookmark(
+    testRoot,
+    uri("http://bar.tld/"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  bs.setItemLastModified(newId14, 1234000000000000);
+  let fakeLastModified = PlacesUtils.toPRTime(
+    (
+      await PlacesUtils.bookmarks.fetch(
+        await PlacesTestUtils.promiseItemGuid(newId14)
+      )
+    ).lastModified
+  );
+  Assert.equal(fakeLastModified, 1234000000000000);
+
+  // bug 378820
+  let uri1 = uri("http://foo.tld/a");
+  bs.insertBookmark(testRoot, uri1, bs.DEFAULT_INDEX, "");
+  await PlacesTestUtils.addVisits(uri1);
+
+  // bug 646993 - test bookmark titles longer than the maximum allowed length
+  let title15 = Array(TITLE_LENGTH_MAX + 5).join("X");
+  let title15expected = title15.substring(0, TITLE_LENGTH_MAX);
+  let newId15 = bs.insertBookmark(
+    testRoot,
+    uri("http://evil.com/"),
+    bs.DEFAULT_INDEX,
+    title15
+  );
+
+  Assert.equal(bs.getItemTitle(newId15).length, title15expected.length);
+  Assert.equal(bookmarksObserver._itemAddedTitle, title15expected);
+  // test title length after updates
+  bs.setItemTitle(newId15, title15 + " updated");
+  Assert.equal(bs.getItemTitle(newId15).length, title15expected.length);
+  Assert.equal(bookmarksObserver._itemTitleChangedId, newId15);
+  Assert.equal(bookmarksObserver._itemTitleChangedTitle, title15expected);
+
+  await testSimpleFolderResult();
+});
+
+async function testSimpleFolderResult() {
+  // the time before we create a folder, in microseconds
+  // Workaround possible VM timers issues subtracting 1us.
+  let beforeCreate = Date.now() * 1000 - 1;
+  Assert.ok(beforeCreate > 0);
+
+  // create a folder
+  let parent = bs.createFolder(root, "test", bs.DEFAULT_INDEX);
+  let parentGuid = await PlacesTestUtils.promiseItemGuid(parent);
+
+  // the time before we insert, in microseconds
+  // Workaround possible VM timers issues subtracting 1ms.
+  let beforeInsert = Date.now() * 1000 - 1;
+  Assert.ok(beforeInsert > 0);
+
+  // re-set item title separately so can test nodes' last modified
+  let item = bs.insertBookmark(
+    parent,
+    uri("about:blank"),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  bs.setItemTitle(item, "test bookmark");
+
+  // see above
+  let folder = bs.createFolder(parent, "test folder", bs.DEFAULT_INDEX);
+  bs.setItemTitle(folder, "test folder");
+
+  let longName = Array(TITLE_LENGTH_MAX + 5).join("A");
+  let folderLongName = bs.createFolder(parent, longName, bs.DEFAULT_INDEX);
+  Assert.equal(
+    bookmarksObserver._itemAddedTitle,
+    longName.substring(0, TITLE_LENGTH_MAX)
+  );
+
+  let options = hs.getNewQueryOptions();
+  let query = hs.getNewQuery();
+  query.setParents([parentGuid]);
+  let result = hs.executeQuery(query, options);
+  let rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 3);
+
+  let node = rootNode.getChild(0);
+  Assert.equal(node.itemId, item);
+  Assert.ok(node.dateAdded > 0);
+  Assert.ok(node.lastModified > 0);
+  Assert.equal(node.title, "test bookmark");
+  node = rootNode.getChild(1);
+  Assert.equal(node.itemId, folder);
+  Assert.equal(node.title, "test folder");
+  Assert.ok(node.dateAdded > 0);
+  Assert.ok(node.lastModified > 0);
+  node = rootNode.getChild(2);
+  Assert.equal(node.itemId, folderLongName);
+  Assert.equal(node.title, longName.substring(0, TITLE_LENGTH_MAX));
+  Assert.ok(node.dateAdded > 0);
+  Assert.ok(node.lastModified > 0);
+
+  // update with another long title
+  bs.setItemTitle(folderLongName, longName + " updated");
+  Assert.equal(bookmarksObserver._itemTitleChangedId, folderLongName);
+  Assert.equal(
+    bookmarksObserver._itemTitleChangedTitle,
+    longName.substring(0, TITLE_LENGTH_MAX)
+  );
+
+  node = rootNode.getChild(2);
+  Assert.equal(node.title, longName.substring(0, TITLE_LENGTH_MAX));
+
+  rootNode.containerOpen = false;
+}
diff --git a/toolkit/components/places/tests/legacy/test_bookmarks_setNullTitle.js b/toolkit/components/places/tests/legacy/test_bookmarks_setNullTitle.js
new file mode 100644
index 0000000000..ff224c3402
--- /dev/null
+++ b/toolkit/components/places/tests/legacy/test_bookmarks_setNullTitle.js
@@ -0,0 +1,50 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Both setItemTitle and insertBookmark should default to the empty string
+ * for null titles.
+ */
+
+const bs = Cc["@mozilla.org/browser/nav-bookmarks-service;1"].getService(
+  Ci.nsINavBookmarksService
+);
+
+const TEST_URL = "http://www.mozilla.org";
+
+function run_test() {
+  // Insert a bookmark with an empty title.
+  var itemId = bs.insertBookmark(
+    bs.tagsFolder,
+    uri(TEST_URL),
+    bs.DEFAULT_INDEX,
+    ""
+  );
+  // Check returned title is an empty string.
+  Assert.equal(bs.getItemTitle(itemId), "");
+  // Set title to null.
+  bs.setItemTitle(itemId, null);
+  // Check returned title defaults to an empty string.
+  Assert.equal(bs.getItemTitle(itemId), "");
+  // Cleanup.
+  bs.removeItem(itemId);
+
+  // Insert a bookmark with a null title.
+  itemId = bs.insertBookmark(
+    bs.tagsFolder,
+    uri(TEST_URL),
+    bs.DEFAULT_INDEX,
+    null
+  );
+  // Check returned title defaults to an empty string.
+  Assert.equal(bs.getItemTitle(itemId), "");
+  // Set title to an empty string.
+  bs.setItemTitle(itemId, "");
+  // Check returned title is an empty string.
+  Assert.equal(bs.getItemTitle(itemId), "");
+  // Cleanup.
+  bs.removeItem(itemId);
+}
diff --git a/toolkit/components/places/tests/legacy/test_protectRoots.js b/toolkit/components/places/tests/legacy/test_protectRoots.js
new file mode 100644
index 0000000000..f6a7fd0fe8
--- /dev/null
+++ b/toolkit/components/places/tests/legacy/test_protectRoots.js
@@ -0,0 +1,21 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async () => {
+  const ROOTS = [
+    PlacesUtils.bookmarks.rootGuid,
+    ...PlacesUtils.bookmarks.userContentRoots,
+    PlacesUtils.bookmarks.tagsGuid,
+  ];
+
+  for (let guid of ROOTS) {
+    Assert.ok(PlacesUtils.isRootItem(guid));
+
+    let id = await PlacesTestUtils.promiseItemId(guid);
+
+    try {
+      PlacesUtils.bookmarks.removeItem(id);
+      do_throw("Trying to remove a root should throw");
+    } catch (ex) {}
+  }
+});
diff --git a/toolkit/components/places/tests/legacy/xpcshell.toml b/toolkit/components/places/tests/legacy/xpcshell.toml
new file mode 100644
index 0000000000..519deef4ff
--- /dev/null
+++ b/toolkit/components/places/tests/legacy/xpcshell.toml
@@ -0,0 +1,11 @@
+[DEFAULT]
+# This directory is for tests for the legacy, sync APIs as somewhere to put them
+# until we remove the APIs themselves.
+head = "head_legacy.js"
+firefox-appdir = "browser"
+
+["test_bookmarks.js"]
+
+["test_bookmarks_setNullTitle.js"]
+
+["test_protectRoots.js"]
diff --git a/toolkit/components/places/tests/maintenance/corruptDB.sqlite b/toolkit/components/places/tests/maintenance/corruptDB.sqlite
new file mode 100644
index 0000000000..b234246cac
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/corruptDB.sqlite
diff --git a/toolkit/components/places/tests/maintenance/corruptPayload.sqlite b/toolkit/components/places/tests/maintenance/corruptPayload.sqlite
new file mode 100644
index 0000000000..16717bda80
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/corruptPayload.sqlite
diff --git a/toolkit/components/places/tests/maintenance/head.js b/toolkit/components/places/tests/maintenance/head.js
new file mode 100644
index 0000000000..3117ab323d
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/head.js
@@ -0,0 +1,119 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+ChromeUtils.defineESModuleGetters(this, {
+  PlacesDBUtils: "resource://gre/modules/PlacesDBUtils.sys.mjs",
+});
+
+async function createCorruptDb(filename) {
+  let path = PathUtils.join(PathUtils.profileDir, filename);
+  await IOUtils.remove(path, { ignoreAbsent: true });
+  // Create a corrupt database.
+  let dir = do_get_cwd().path;
+  let src = PathUtils.join(dir, "corruptDB.sqlite");
+  await IOUtils.copy(src, path);
+}
+
+/**
+ * Used in _replaceOnStartup_ tests as common test code. It checks whether we
+ * are properly cloning or replacing a corrupt database.
+ *
+ * @param {string[]} src
+ *        Array of strings which form a path to a test database, relative to
+ *        the parent of this test folder.
+ * @param {string} filename
+ *        Database file name
+ * @param {boolean} shouldClone
+ *        Whether we expect the database to be cloned
+ * @param {boolean} dbStatus
+ *        The expected final database status
+ */
+async function test_database_replacement(src, filename, shouldClone, dbStatus) {
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref("places.database.cloneOnCorruption");
+  });
+  Services.prefs.setBoolPref("places.database.cloneOnCorruption", shouldClone);
+
+  // Only the main database file (places.sqlite) will be cloned, because
+  // attached databased would break due to OS file lockings.
+  let willClone = shouldClone && filename == DB_FILENAME;
+
+  // Ensure that our databases don't exist yet.
+  let dest = PathUtils.join(PathUtils.profileDir, filename);
+  Assert.ok(
+    !(await IOUtils.exists(dest)),
+    `"${filename} should not exist initially`
+  );
+  let corrupt = PathUtils.join(PathUtils.profileDir, `${filename}.corrupt`);
+  Assert.ok(
+    !(await IOUtils.exists(corrupt)),
+    `${filename}.corrupt should not exist initially`
+  );
+
+  let dir = PathUtils.parent(do_get_cwd().path);
+  src = PathUtils.join(dir, ...src);
+  await IOUtils.copy(src, dest);
+
+  // Create some unique stuff to check later.
+  let db = await Sqlite.openConnection({ path: dest });
+  await db.execute(`CREATE TABLE moz_cloned (id INTEGER PRIMARY KEY)`);
+  await db.execute(`CREATE TABLE not_cloned (id INTEGER PRIMARY KEY)`);
+  await db.execute(`DELETE FROM moz_cloned`); // Shouldn't throw.
+  await db.close();
+
+  // Open the database with Places.
+  Services.prefs.setCharPref(
+    "places.database.replaceDatabaseOnStartup",
+    filename
+  );
+  Assert.equal(PlacesUtils.history.databaseStatus, dbStatus);
+
+  Assert.ok(await IOUtils.exists(dest), "The database should exist");
+
+  // Check the new database still contains our special data.
+  db = await Sqlite.openConnection({ path: dest });
+  if (willClone) {
+    await db.execute(`DELETE FROM moz_cloned`); // Shouldn't throw.
+  }
+
+  // Check the new database is really a new one.
+  await Assert.rejects(
+    db.execute(`DELETE FROM not_cloned`),
+    /no such table/,
+    "The database should have been replaced"
+  );
+  await db.close();
+
+  if (willClone) {
+    Assert.ok(
+      !(await IOUtils.exists(corrupt)),
+      "The corrupt db should not exist"
+    );
+    Assert.ok(
+      !(await IOUtils.exists(corrupt + "-wal")),
+      "The corrupt db wal should not exist"
+    );
+    Assert.ok(
+      !(await IOUtils.exists(corrupt + "-shm")),
+      "The corrupt db shm should not exist"
+    );
+  } else {
+    Assert.ok(await IOUtils.exists(corrupt), "The corrupt db should exist");
+  }
+
+  Assert.equal(
+    Services.prefs.getCharPref("places.database.replaceDatabaseOnStartup", ""),
+    "",
+    "The replaceDatabaseOnStartup pref should have been unset"
+  );
+}
diff --git a/toolkit/components/places/tests/maintenance/test_corrupt_favicons.js b/toolkit/components/places/tests/maintenance/test_corrupt_favicons.js
new file mode 100644
index 0000000000..2021428a62
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_corrupt_favicons.js
@@ -0,0 +1,16 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a corrupt favicons file
+// that can't be opened.
+
+add_task(async function () {
+  await createCorruptDb("favicons.sqlite");
+
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CREATE
+  );
+  let db = await PlacesUtils.promiseDBConnection();
+  await db.execute("SELECT * FROM moz_icons"); // Should not fail.
+});
diff --git a/toolkit/components/places/tests/maintenance/test_corrupt_favicons_schema.js b/toolkit/components/places/tests/maintenance/test_corrupt_favicons_schema.js
new file mode 100644
index 0000000000..299bbca65d
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_corrupt_favicons_schema.js
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a corrupt places schema.
+
+add_task(async function () {
+  let path = await setupPlacesDatabase(["migration", "favicons_v41.sqlite"]);
+
+  // Ensure the database will go through a migration that depends on moz_places
+  // and break the schema by dropping that table.
+  let db = await Sqlite.openConnection({ path });
+  await db.setSchemaVersion(38);
+  await db.execute("DROP TABLE moz_icons");
+  await db.close();
+
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CORRUPT
+  );
+  db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute("SELECT 1 FROM moz_icons");
+  Assert.equal(rows.length, 0, "Found no icons");
+});
diff --git a/toolkit/components/places/tests/maintenance/test_corrupt_places_schema.js b/toolkit/components/places/tests/maintenance/test_corrupt_places_schema.js
new file mode 100644
index 0000000000..6f184d517f
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_corrupt_places_schema.js
@@ -0,0 +1,21 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a corrupt places schema.
+
+add_task(async function () {
+  let path = await setupPlacesDatabase(["migration", "places_v52.sqlite"]);
+
+  // Ensure the database will go through a migration that depends on moz_places
+  // and break the schema by dropping that table.
+  let db = await Sqlite.openConnection({ path });
+  await db.execute("DROP TABLE moz_places");
+  await db.close();
+
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CORRUPT
+  );
+  db = await PlacesUtils.promiseDBConnection();
+  await db.execute("SELECT * FROM moz_places LIMIT 1"); // Should not fail.
+});
diff --git a/toolkit/components/places/tests/maintenance/test_corrupt_telemetry.js b/toolkit/components/places/tests/maintenance/test_corrupt_telemetry.js
new file mode 100644
index 0000000000..d6659267da
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_corrupt_telemetry.js
@@ -0,0 +1,24 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a request to forcibly
+// replace the current database.
+
+add_task(async function () {
+  await createCorruptDb("places.sqlite");
+
+  let count = Services.telemetry
+    .getHistogramById("PLACES_DATABASE_CORRUPTION_HANDLING_STAGE")
+    .snapshot().values[3];
+  Assert.equal(count, undefined, "There should be no telemetry");
+
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CORRUPT
+  );
+
+  count = Services.telemetry
+    .getHistogramById("PLACES_DATABASE_CORRUPTION_HANDLING_STAGE")
+    .snapshot().values[3];
+  Assert.equal(count, 1, "Telemetry should have been added");
+});
diff --git a/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup.js b/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup.js
new file mode 100644
index 0000000000..d48b32f5d6
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup.js
@@ -0,0 +1,14 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a request to forcibly
+// replace the current database.
+
+add_task(async function () {
+  await test_database_replacement(
+    ["migration", "favicons_v41.sqlite"],
+    "favicons.sqlite",
+    false,
+    PlacesUtils.history.DATABASE_STATUS_CREATE
+  );
+});
diff --git a/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup_clone.js b/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup_clone.js
new file mode 100644
index 0000000000..f6ff2379a0
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_favicons_replaceOnStartup_clone.js
@@ -0,0 +1,16 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a request to forcibly
+// replace the current database.
+
+add_task(async function () {
+  // In reality, this won't try to clone the database, because attached
+  // databases cannot be supported when cloning. This test also verifies that.
+  await test_database_replacement(
+    ["migration", "favicons_v41.sqlite"],
+    "favicons.sqlite",
+    true,
+    PlacesUtils.history.DATABASE_STATUS_CREATE
+  );
+});
diff --git a/toolkit/components/places/tests/maintenance/test_integrity_replacement.js b/toolkit/components/places/tests/maintenance/test_integrity_replacement.js
new file mode 100644
index 0000000000..dde8fd16a3
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_integrity_replacement.js
@@ -0,0 +1,17 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that integrity check will replace a corrupt database.
+
+add_task(async function () {
+  await setupPlacesDatabase("corruptPayload.sqlite");
+  await Assert.rejects(
+    PlacesDBUtils.checkIntegrity(),
+    /will be replaced on next startup/,
+    "Should reject on corruption"
+  );
+  Assert.equal(
+    Services.prefs.getCharPref("places.database.replaceDatabaseOnStartup"),
+    DB_FILENAME
+  );
+});
diff --git a/toolkit/components/places/tests/maintenance/test_places_purge_caches.js b/toolkit/components/places/tests/maintenance/test_places_purge_caches.js
new file mode 100644
index 0000000000..dc3e8452f1
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_places_purge_caches.js
@@ -0,0 +1,31 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test whether purge-caches event works collectry when maintenance the places.
+
+add_task(async function test_history() {
+  await PlacesTestUtils.addVisits({ uri: "http://example.com/" });
+  await assertPurgingCaches();
+});
+
+add_task(async function test_bookmark() {
+  await PlacesTestUtils.addBookmarkWithDetails({ uri: "http://example.com/" });
+  await assertPurgingCaches();
+});
+
+async function assertPurgingCaches() {
+  const query = PlacesUtils.history.getNewQuery();
+  const options = PlacesUtils.history.getNewQueryOptions();
+  const result = PlacesUtils.history.executeQuery(query, options);
+  result.root.containerOpen = true;
+
+  const onInvalidateContainer = new Promise(resolve => {
+    const resultObserver = new NavHistoryResultObserver();
+    resultObserver.invalidateContainer = resolve;
+    result.addObserver(resultObserver, false);
+  });
+
+  await PlacesDBUtils.maintenanceOnIdle();
+  await onInvalidateContainer;
+  ok(true, "InvalidateContainer is called");
+}
diff --git a/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup.js b/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup.js
new file mode 100644
index 0000000000..0c389bb18d
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup.js
@@ -0,0 +1,14 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a request to forcibly
+// replace the current database.
+
+add_task(async function () {
+  await test_database_replacement(
+    ["migration", "places_v52.sqlite"],
+    "places.sqlite",
+    false,
+    PlacesUtils.history.DATABASE_STATUS_CORRUPT
+  );
+});
diff --git a/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup_clone.js b/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup_clone.js
new file mode 100644
index 0000000000..7b984a2bef
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_places_replaceOnStartup_clone.js
@@ -0,0 +1,14 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that history initialization correctly handles a request to forcibly
+// replace the current database.
+
+add_task(async function () {
+  await test_database_replacement(
+    ["migration", "places_v52.sqlite"],
+    "places.sqlite",
+    true,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+});
diff --git a/toolkit/components/places/tests/maintenance/test_preventive_maintenance.js b/toolkit/components/places/tests/maintenance/test_preventive_maintenance.js
new file mode 100644
index 0000000000..5aeb565aa1
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_preventive_maintenance.js
@@ -0,0 +1,2744 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test preventive maintenance
+ * For every maintenance query create an uncoherent db and check that we take
+ * correct fix steps, without polluting valid data.
+ */
+
+// ------------------------------------------------------------------------------
+// Helpers
+
+var defaultBookmarksMaxId = 0;
+async function cleanDatabase() {
+  // First clear any bookmarks the "proper way" to ensure caches like GuidHelper
+  // are properly cleared.
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.withConnectionWrapper("cleanDatabase", async db => {
+    await db.executeTransaction(async () => {
+      await db.executeCached("DELETE FROM moz_places");
+      await db.executeCached("DELETE FROM moz_origins");
+      await db.executeCached("DELETE FROM moz_historyvisits");
+      await db.executeCached("DELETE FROM moz_anno_attributes");
+      await db.executeCached("DELETE FROM moz_annos");
+      await db.executeCached("DELETE FROM moz_inputhistory");
+      await db.executeCached("DELETE FROM moz_keywords");
+      await db.executeCached("DELETE FROM moz_icons");
+      await db.executeCached("DELETE FROM moz_pages_w_icons");
+      await db.executeCached(
+        "DELETE FROM moz_bookmarks WHERE id > " + defaultBookmarksMaxId
+      );
+      await db.executeCached("DELETE FROM moz_bookmarks_deleted");
+      await db.executeCached("DELETE FROM moz_places_metadata_search_queries");
+    });
+  });
+}
+
+async function addPlace(
+  aUrl,
+  aFavicon,
+  aGuid = PlacesUtils.history.makeGuid(),
+  aHash = null
+) {
+  let href = new URL(
+    aUrl || `http://www.mozilla.org/${encodeURIComponent(aGuid)}`
+  ).href;
+  let id;
+  await PlacesUtils.withConnectionWrapper("cleanDatabase", async db => {
+    await db.executeTransaction(async () => {
+      id = (
+        await db.executeCached(
+          `INSERT INTO moz_places (url, url_hash, guid)
+           VALUES (:url, IFNULL(:hash, hash(:url)), :guid)
+           RETURNING id`,
+          {
+            url: href,
+            hash: aHash,
+            guid: aGuid,
+          }
+        )
+      )[0].getResultByIndex(0);
+
+      if (aFavicon) {
+        await db.executeCached(
+          `INSERT INTO moz_pages_w_icons (page_url, page_url_hash)
+           VALUES (:url, IFNULL(:hash, hash(:url)))`,
+          {
+            url: href,
+            hash: aHash,
+          }
+        );
+        await db.executeCached(
+          `INSERT INTO moz_icons_to_pages (page_id, icon_id)
+           VALUES (
+            (SELECT id FROM moz_pages_w_icons WHERE page_url_hash = IFNULL(:hash, hash(:url))),
+            :favicon
+           )`,
+          {
+            url: href,
+            hash: aHash,
+            favicon: aFavicon,
+          }
+        );
+      }
+    });
+  });
+  return id;
+}
+
+async function addBookmark(
+  aPlaceId,
+  aType,
+  aParentGuid = PlacesUtils.bookmarks.unfiledGuid,
+  aKeywordId,
+  aTitle,
+  aGuid = PlacesUtils.history.makeGuid(),
+  aSyncStatus = PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+  aSyncChangeCounter = 0
+) {
+  return PlacesUtils.withConnectionWrapper("addBookmark", async db => {
+    return (
+      await db.executeCached(
+        `INSERT INTO moz_bookmarks (fk, type, parent, keyword_id,
+                                  title, guid, syncStatus, syncChangeCounter)
+         VALUES (:place_id, :type,
+                 (SELECT id FROM moz_bookmarks WHERE guid = :parent), :keyword_id,
+                  :title, :guid, :sync_status, :change_counter)
+         RETURNING id`,
+        {
+          place_id: aPlaceId || null,
+          type: aType || null,
+          parent: aParentGuid,
+          keyword_id: aKeywordId || null,
+          title: typeof aTitle == "string" ? aTitle : null,
+          guid: aGuid,
+          sync_status: aSyncStatus,
+          change_counter: aSyncChangeCounter,
+        }
+      )
+    )[0].getResultByIndex(0);
+  });
+}
+
+// ------------------------------------------------------------------------------
+// Tests
+
+var tests = [];
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "A.1",
+  desc: "Remove obsolete annotations from moz_annos",
+
+  _obsoleteWeaveAttribute: "weave/test",
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid.
+    this._placeId = await addPlace();
+    // Add an obsolete attribute.
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeTransaction(async () => {
+        db.executeCached(
+          "INSERT INTO moz_anno_attributes (name) VALUES (:anno)",
+          { anno: this._obsoleteWeaveAttribute }
+        );
+
+        db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+           VALUES (:place_id,
+             (SELECT id FROM moz_anno_attributes WHERE name = :anno)
+           )`,
+          {
+            place_id: this._placeId,
+            anno: this._obsoleteWeaveAttribute,
+          }
+        );
+      });
+    });
+  },
+
+  async check() {
+    // Check that the obsolete annotation has been removed.
+    Assert.strictEqual(
+      await PlacesTestUtils.getDatabaseValue("moz_anno_attributes", "id", {
+        name: this._obsoleteWeaveAttribute,
+      }),
+      undefined
+    );
+  },
+});
+
+tests.push({
+  name: "A.3",
+  desc: "Remove unused attributes",
+
+  _usedPageAttribute: "usedPage",
+  _unusedAttribute: "unused",
+  _placeId: null,
+  _bookmarkId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // add a bookmark
+    this._bookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeTransaction(async () => {
+        // Add a used attribute and an unused one.
+        await db.executeCached(
+          `INSERT INTO moz_anno_attributes (name)
+           VALUES (:anno1), (:anno2)`,
+          {
+            anno1: this._usedPageAttribute,
+            anno2: this._unusedAttribute,
+          }
+        );
+        await db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+           VALUES(:place_id, (SELECT id FROM moz_anno_attributes WHERE name = :anno))`,
+          {
+            place_id: this._placeId,
+            anno: this._usedPageAttribute,
+          }
+        );
+      });
+    });
+  },
+
+  async check() {
+    // Check that used attributes are still there
+    let value = await PlacesTestUtils.getDatabaseValue(
+      "moz_anno_attributes",
+      "id",
+      {
+        name: this._usedPageAttribute,
+      }
+    );
+    Assert.notStrictEqual(value, undefined);
+    // Check that unused attribute has been removed
+    value = await PlacesTestUtils.getDatabaseValue(
+      "moz_anno_attributes",
+      "id",
+      {
+        name: this._unusedAttribute,
+      }
+    );
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "B.1",
+  desc: "Remove annotations with an invalid attribute",
+
+  _usedPageAttribute: "usedPage",
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeTransaction(async () => {
+        // Add a used attribute.
+        await db.executeCached(
+          "INSERT INTO moz_anno_attributes (name) VALUES (:anno)",
+          { anno: this._usedPageAttribute }
+        );
+        await db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+           VALUES(:place_id, (SELECT id FROM moz_anno_attributes WHERE name = :anno))`,
+          {
+            place_id: this._placeId,
+            anno: this._usedPageAttribute,
+          }
+        );
+        // Add an annotation with a nonexistent attribute
+        await db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+           VALUES(:place_id, 1337)`,
+          { place_id: this._placeId }
+        );
+      });
+    });
+  },
+
+  async check() {
+    // Check that used attribute is still there
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      "SELECT id FROM moz_anno_attributes WHERE name = :anno",
+      { anno: this._usedPageAttribute }
+    );
+    Assert.equal(rows.length, 1);
+    // check that annotation with valid attribute is still there
+    rows = await db.executeCached(
+      `SELECT id FROM moz_annos
+       WHERE anno_attribute_id = (SELECT id FROM moz_anno_attributes WHERE name = :anno)`,
+      { anno: this._usedPageAttribute }
+    );
+    Assert.equal(rows.length, 1);
+    // Check that annotation with bogus attribute has been removed
+    let value = await PlacesTestUtils.getDatabaseValue("moz_annos", "id", {
+      anno_attribute_id: 1337,
+    });
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "B.2",
+  desc: "Remove orphan page annotations",
+
+  _usedPageAttribute: "usedPage",
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeTransaction(async () => {
+        // Add a used attribute.
+        await db.executeCached(
+          "INSERT INTO moz_anno_attributes (name) VALUES (:anno)",
+          { anno: this._usedPageAttribute }
+        );
+        await db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+           VALUES(:place_id, (SELECT id FROM moz_anno_attributes WHERE name = :anno))`,
+          { place_id: this._placeId, anno: this._usedPageAttribute }
+        );
+        // Add an annotation to a nonexistent page
+        await db.executeCached(
+          `INSERT INTO moz_annos (place_id, anno_attribute_id)
+          VALUES(:place_id, (SELECT id FROM moz_anno_attributes WHERE name = :anno))`,
+          { place_id: 1337, anno: this._usedPageAttribute }
+        );
+      });
+    });
+  },
+
+  async check() {
+    // Check that used attribute is still there
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      "SELECT id FROM moz_anno_attributes WHERE name = :anno",
+      { anno: this._usedPageAttribute }
+    );
+    Assert.equal(rows.length, 1);
+    // check that annotation with valid attribute is still there
+    rows = await db.executeCached(
+      `SELECT id FROM moz_annos
+       WHERE anno_attribute_id = (SELECT id FROM moz_anno_attributes WHERE name = :anno)`,
+      { anno: this._usedPageAttribute }
+    );
+    Assert.equal(rows.length, 1);
+    // Check that an annotation to a nonexistent page has been removed
+    let value = await PlacesTestUtils.getDatabaseValue("moz_annos", "id", {
+      place_id: 1337,
+    });
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.9",
+  desc: "Remove items without a valid place",
+
+  _validItemId: null,
+  _invalidItemId: null,
+  _invalidSyncedItemId: null,
+  placeId: null,
+
+  _changeCounterStmt: null,
+  _menuChangeCounter: -1,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this.placeId = await addPlace();
+    // Insert a valid bookmark
+    this._validItemId = await addBookmark(
+      this.placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    // Insert a bookmark with an invalid place
+    this._invalidItemId = await addBookmark(
+      1337,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    // Insert a synced bookmark with an invalid place. We should write a
+    // tombstone when we remove it.
+    this._invalidSyncedItemId = await addBookmark(
+      1337,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      PlacesUtils.bookmarks.menuGuid,
+      null,
+      null,
+      "bookmarkAAAA",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+    // Insert a folder referencing a nonexistent place ID. D.5 should convert
+    // it to a bookmark; D.9 should remove it.
+    this._invalidWrongTypeItemId = await addBookmark(
+      1337,
+      PlacesUtils.bookmarks.TYPE_FOLDER
+    );
+
+    let value = await PlacesTestUtils.getDatabaseValue(
+      "moz_bookmarks",
+      "syncChangeCounter",
+      {
+        guid: PlacesUtils.bookmarks.menuGuid,
+      }
+    );
+    Assert.equal(value, 0);
+    this._menuChangeCounter = value;
+  },
+
+  async check() {
+    // Check that valid bookmark is still there
+    let value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+      id: this._validItemId,
+    });
+    Assert.notStrictEqual(value, undefined);
+    // Check that invalid bookmarks have been removed
+    for (let id of [
+      this._invalidItemId,
+      this._invalidSyncedItemId,
+      this._invalidWrongTypeItemId,
+    ]) {
+      value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+        id,
+      });
+      Assert.strictEqual(value, undefined);
+    }
+
+    value = await PlacesTestUtils.getDatabaseValue(
+      "moz_bookmarks",
+      "syncChangeCounter",
+      { guid: PlacesUtils.bookmarks.menuGuid }
+    );
+    Assert.equal(value, 1);
+    Assert.equal(value, this._menuChangeCounter + 1);
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["bookmarkAAAA"]
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.1",
+  desc: "Remove items that are not uri bookmarks from tag containers",
+
+  _tagId: null,
+  _bookmarkId: null,
+  _separatorId: null,
+  _folderId: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Create a tag
+    this._tagId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.tagsGuid
+    );
+    let tagGuid = await PlacesTestUtils.promiseItemGuid(this._tagId);
+    // Insert a bookmark in the tag
+    this._bookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      tagGuid
+    );
+    // Insert a separator in the tag
+    this._separatorId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      tagGuid
+    );
+    // Insert a folder in the tag
+    this._folderId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      tagGuid
+    );
+  },
+
+  async check() {
+    // Check that valid bookmark is still there
+    let value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      parent: this._tagId,
+    });
+    Assert.notStrictEqual(value, undefined);
+    // Check that separator is no more there
+    value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      parent: this._tagId,
+    });
+    Assert.equal(value, undefined);
+    // Check that folder is no more there
+    value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      parent: this._tagId,
+    });
+    Assert.equal(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.2",
+  desc: "Remove empty tags",
+
+  _tagId: null,
+  _bookmarkId: null,
+  _emptyTagId: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Create a tag
+    this._tagId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.tagsGuid
+    );
+    let tagGuid = await PlacesTestUtils.promiseItemGuid(this._tagId);
+    // Insert a bookmark in the tag
+    this._bookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      tagGuid
+    );
+    // Create another tag (empty)
+    this._emptyTagId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.tagsGuid
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    // Check that valid bookmark is still there
+    let value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "id", {
+      id: this._bookmarkId,
+      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      parent: this._tagId,
+    });
+    Assert.notStrictEqual(value, undefined);
+    let rows = await db.executeCached(
+      `SELECT b.id FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      WHERE b.id = :id AND b.type = :type AND p.guid = :parent`,
+      {
+        id: this._tagId,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        parent: PlacesUtils.bookmarks.tagsGuid,
+      }
+    );
+    Assert.equal(rows.length, 1);
+    rows = await db.executeCached(
+      `SELECT b.id FROM moz_bookmarks b
+      JOIN moz_bookmarks p ON p.id = b.parent
+      WHERE b.id = :id AND b.type = :type AND p.guid = :parent`,
+      {
+        id: this._emptyTagId,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        parent: PlacesUtils.bookmarks.tagsGuid,
+      }
+    );
+    Assert.equal(rows.length, 0);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.3",
+  desc: "Move orphan items to unsorted folder",
+
+  _orphanBookmarkId: null,
+  _orphanSeparatorId: null,
+  _orphanFolderId: null,
+  _bookmarkId: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Insert an orphan bookmark
+    this._orphanBookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      8888
+    );
+    // Insert an orphan separator
+    this._orphanSeparatorId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      8888
+    );
+    // Insert a orphan folder
+    this._orphanFolderId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      8888
+    );
+    let folderGuid = await PlacesTestUtils.promiseItemGuid(
+      this._orphanFolderId
+    );
+    // Create a child of the last created folder
+    this._bookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      folderGuid
+    );
+  },
+
+  async check() {
+    // Check that bookmarks are now children of a real folder (unfiled)
+    let expectedInfos = [
+      {
+        id: this._orphanBookmarkId,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._orphanSeparatorId,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._orphanFolderId,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._bookmarkId,
+        parent: await PlacesTestUtils.promiseItemGuid(this._orphanFolderId),
+        syncChangeCounter: 0,
+      },
+      {
+        id: await PlacesTestUtils.promiseItemId(
+          PlacesUtils.bookmarks.unfiledGuid
+        ),
+        parent: PlacesUtils.bookmarks.rootGuid,
+        syncChangeCounter: 3,
+      },
+    ];
+    let db = await PlacesUtils.promiseDBConnection();
+    for (let { id, parent, syncChangeCounter } of expectedInfos) {
+      let rows = await db.executeCached(
+        `
+        SELECT b.id, b.syncChangeCounter
+        FROM moz_bookmarks b
+        JOIN moz_bookmarks p ON b.parent = p.id
+        WHERE b.id = :item_id
+          AND p.guid = :parent`,
+        { item_id: id, parent }
+      );
+      Assert.equal(rows.length, 1);
+
+      let actualChangeCounter = rows[0].getResultByName("syncChangeCounter");
+      Assert.equal(actualChangeCounter, syncChangeCounter);
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.5",
+  desc: "Fix wrong item types | folders and separators",
+
+  _separatorId: null,
+  _separatorGuid: null,
+  _folderId: null,
+  _folderGuid: null,
+  _syncedFolderId: null,
+  _syncedFolderGuid: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Add a separator with a fk
+    this._separatorId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR
+    );
+    this._separatorGuid = await PlacesTestUtils.promiseItemGuid(
+      this._separatorId
+    );
+    // Add a folder with a fk
+    this._folderId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_FOLDER
+    );
+    this._folderGuid = await PlacesTestUtils.promiseItemGuid(this._folderId);
+    // Add a synced folder with a fk
+    this._syncedFolderId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      null,
+      "itemAAAAAAAA",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+    this._syncedFolderGuid = await PlacesTestUtils.promiseItemGuid(
+      this._syncedFolderId
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    // Check that items with an fk have been converted to bookmarks
+    let rows = await db.executeCached(
+      `SELECT id, guid, syncChangeCounter
+       FROM moz_bookmarks
+       WHERE id = :item_id AND type = :type`,
+      { item_id: this._separatorId, type: PlacesUtils.bookmarks.TYPE_BOOKMARK }
+    );
+    Assert.equal(rows.length, 1);
+    let expected = [
+      {
+        id: this._folderId,
+        oldGuid: this._folderGuid,
+      },
+      {
+        id: this._syncedFolderId,
+        oldGuid: this._syncedFolderGuid,
+      },
+    ];
+    for (let { id, oldGuid } of expected) {
+      rows = await db.executeCached(
+        `SELECT id, guid, syncChangeCounter
+         FROM moz_bookmarks
+         WHERE id = :item_id AND type = :type`,
+        { item_id: id, type: PlacesUtils.bookmarks.TYPE_BOOKMARK }
+      );
+      Assert.equal(rows.length, 1);
+      Assert.notEqual(rows[0].getResultByName("guid"), oldGuid);
+      Assert.equal(rows[0].getResultByName("syncChangeCounter"), 1);
+    }
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["itemAAAAAAAA"]
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.6",
+  desc: "Fix wrong item types | bookmarks",
+
+  _validBookmarkId: null,
+  _validBookmarkGuid: null,
+  _invalidBookmarkId: null,
+  _invalidBookmarkGuid: null,
+  _invalidSyncedBookmarkId: null,
+  _invalidSyncedBookmarkGuid: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Add a bookmark with a valid place id
+    this._validBookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    this._validBookmarkGuid = await PlacesTestUtils.promiseItemGuid(
+      this._validBookmarkId
+    );
+    // Add a bookmark with a null place id
+    this._invalidBookmarkId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    this._invalidBookmarkGuid = await PlacesTestUtils.promiseItemGuid(
+      this._invalidBookmarkId
+    );
+    // Add a synced bookmark with a null place id
+    this._invalidSyncedBookmarkId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      null,
+      "bookmarkAAAA",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+    this._invalidSyncedBookmarkGuid = await PlacesTestUtils.promiseItemGuid(
+      this._invalidSyncedBookmarkId
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    // Check valid bookmark
+    let rows = await db.executeCached(
+      `SELECT id, guid, syncChangeCounter
+       FROM moz_bookmarks
+       WHERE id = :item_id AND type = :type`,
+      {
+        item_id: this._validBookmarkId,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      }
+    );
+    Assert.equal(rows.length, 1);
+    Assert.equal(rows[0].getResultByName("syncChangeCounter"), 0);
+    Assert.equal(
+      await PlacesTestUtils.promiseItemId(this._validBookmarkGuid),
+      this._validBookmarkId
+    );
+
+    // Check invalid bookmarks have been converted to folders
+    let expected = [
+      {
+        id: this._invalidBookmarkId,
+        oldGuid: this._invalidBookmarkGuid,
+      },
+      {
+        id: this._invalidSyncedBookmarkId,
+        oldGuid: this._invalidSyncedBookmarkGuid,
+      },
+    ];
+    for (let { id, oldGuid } of expected) {
+      rows = await db.executeCached(
+        `SELECT id, guid, syncChangeCounter
+         FROM moz_bookmarks
+         WHERE id = :item_id AND type = :type`,
+        { item_id: id, type: PlacesUtils.bookmarks.TYPE_FOLDER }
+      );
+      Assert.equal(rows.length, 1);
+      Assert.notEqual(rows[0].getResultByName("guid"), oldGuid);
+      Assert.equal(rows[0].getResultByName("syncChangeCounter"), 1);
+    }
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["bookmarkAAAA"]
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.7",
+  desc: "Fix missing item types",
+
+  _placeId: null,
+  _bookmarkId: null,
+  _bookmarkGuid: null,
+  _syncedBookmarkId: null,
+  _syncedBookmarkGuid: null,
+  _folderId: null,
+  _folderGuid: null,
+  _syncedFolderId: null,
+  _syncedFolderGuid: null,
+
+  async setup() {
+    // Item without a type but with a place ID; should be converted to a
+    // bookmark. The synced bookmark should be handled the same way, but with
+    // a tombstone.
+    this._placeId = await addPlace();
+    this._bookmarkId = await addBookmark(this._placeId);
+    this._bookmarkGuid = await PlacesTestUtils.promiseItemGuid(
+      this._bookmarkId
+    );
+    this._syncedBookmarkId = await addBookmark(
+      this._placeId,
+      null,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      null,
+      "bookmarkAAAA",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+    this._syncedBookmarkGuid = await PlacesTestUtils.promiseItemGuid(
+      this._syncedBookmarkId
+    );
+
+    // Item without a type and without a place ID; should be converted to a
+    // folder.
+    this._folderId = await addBookmark();
+    this._folderGuid = await PlacesTestUtils.promiseItemGuid(this._folderId);
+    this._syncedFolderId = await addBookmark(
+      null,
+      null,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      null,
+      "folderBBBBBB",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+    this._syncedFolderGuid = await PlacesTestUtils.promiseItemGuid(
+      this._syncedFolderId
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let expected = [
+      {
+        id: this._bookmarkId,
+        oldGuid: this._bookmarkGuid,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._syncedBookmarkId,
+        oldGuid: this._syncedBookmarkGuid,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._folderId,
+        oldGuid: this._folderGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._syncedFolderId,
+        oldGuid: this._syncedFolderGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        syncChangeCounter: 1,
+      },
+    ];
+    for (let { id, oldGuid, type, syncChangeCounter } of expected) {
+      let rows = await db.executeCached(
+        `SELECT id, guid, type, syncChangeCounter
+         FROM moz_bookmarks
+         WHERE id = :item_id`,
+        { item_id: id }
+      );
+      Assert.equal(rows.length, 1);
+      Assert.equal(rows[0].getResultByName("type"), type);
+      Assert.equal(
+        rows[0].getResultByName("syncChangeCounter"),
+        syncChangeCounter
+      );
+      Assert.notEqual(rows[0].getResultByName("guid"), oldGuid);
+    }
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["bookmarkAAAA", "folderBBBBBB"]
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.8",
+  desc: "Fix wrong parents",
+
+  _bookmarkId: null,
+  _separatorId: null,
+  _bookmarkId1: null,
+  _bookmarkId2: null,
+  _placeId: null,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Insert a bookmark
+    this._bookmarkId = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK
+    );
+    // Insert a separator
+    this._separatorId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR
+    );
+    // Create 3 children of these items
+    let bookmarkGuid = await PlacesTestUtils.promiseItemGuid(this._bookmarkId);
+    this._bookmarkId1 = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      bookmarkGuid
+    );
+    let separatorGuid = await PlacesTestUtils.promiseItemGuid(
+      this._separatorId
+    );
+    this._bookmarkId2 = await addBookmark(
+      this._placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      separatorGuid
+    );
+  },
+
+  async check() {
+    // Check that bookmarks are now children of a real folder (unfiled)
+    let expectedInfos = [
+      {
+        id: this._bookmarkId1,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        syncChangeCounter: 1,
+      },
+      {
+        id: this._bookmarkId2,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        syncChangeCounter: 1,
+      },
+      {
+        id: await PlacesTestUtils.promiseItemId(
+          PlacesUtils.bookmarks.unfiledGuid
+        ),
+        parent: PlacesUtils.bookmarks.rootGuid,
+        syncChangeCounter: 2,
+      },
+    ];
+    let db = await PlacesUtils.promiseDBConnection();
+    for (let { id, parent, syncChangeCounter } of expectedInfos) {
+      let rows = await db.executeCached(
+        `
+        SELECT b.id, b.syncChangeCounter
+        FROM moz_bookmarks b
+        JOIN moz_bookmarks p ON b.parent = p.id
+        WHERE b.id = :item_id AND p.guid = :parent`,
+        { item_id: id, parent }
+      );
+      Assert.equal(rows.length, 1);
+
+      let actualChangeCounter = rows[0].getResultByName("syncChangeCounter");
+      Assert.equal(actualChangeCounter, syncChangeCounter);
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.10",
+  desc: "Recalculate positions",
+
+  _unfiledBookmarks: [],
+  _toolbarBookmarks: [],
+
+  async setup() {
+    const NUM_BOOKMARKS = 20;
+    let children = [];
+    for (let i = 0; i < NUM_BOOKMARKS; i++) {
+      children.push({
+        title: "testbookmark",
+        url: "http://example.com",
+      });
+    }
+
+    // Add bookmarks to two folders to better perturbate the table.
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.unfiledGuid,
+      children,
+      source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    });
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.toolbarGuid,
+      children,
+      source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    });
+
+    async function randomize_positions(aParent, aResultArray) {
+      await PlacesUtils.withConnectionWrapper("setup", async db => {
+        await db.executeTransaction(async () => {
+          for (let i = 0; i < NUM_BOOKMARKS / 2; i++) {
+            await db.executeCached(
+              `UPDATE moz_bookmarks SET position = :rand
+               WHERE id IN (
+                 SELECT b.id FROM moz_bookmarks b
+                 JOIN moz_bookmarks p ON b.parent = p.id
+                 WHERE p.guid = :parent
+                 ORDER BY RANDOM() LIMIT 1
+               )`,
+              {
+                parent: aParent,
+                rand: Math.round(Math.random() * (NUM_BOOKMARKS - 1)),
+              }
+            );
+          }
+
+          // Build the expected ordered list of bookmarks.
+          let rows = await db.executeCached(
+            `SELECT b.id
+             FROM moz_bookmarks b
+             JOIN moz_bookmarks p ON b.parent = p.id
+             WHERE p.guid = :parent
+             ORDER BY b.position ASC, b.ROWID ASC`,
+            { parent: aParent }
+          );
+          rows.forEach(r => {
+            aResultArray.push(r.getResultByName("id"));
+          });
+          await PlacesTestUtils.dumpTable({
+            db,
+            table: "moz_bookmarks",
+            columns: ["id", "parent", "position"],
+          });
+        });
+      });
+    }
+
+    // Set random positions for the added bookmarks.
+    await randomize_positions(
+      PlacesUtils.bookmarks.unfiledGuid,
+      this._unfiledBookmarks
+    );
+    await randomize_positions(
+      PlacesUtils.bookmarks.toolbarGuid,
+      this._toolbarBookmarks
+    );
+
+    let syncInfos = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.unfiledGuid,
+      PlacesUtils.bookmarks.toolbarGuid
+    );
+    Assert.ok(syncInfos.every(info => info.syncChangeCounter === 0));
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+
+    async function check_order(aParent, aResultArray) {
+      // Build the expected ordered list of bookmarks.
+      let childRows = await db.executeCached(
+        `SELECT b.id, b.position, b.syncChangeCounter
+         FROM moz_bookmarks b
+         JOIN moz_bookmarks p ON b.parent = p.id
+         WHERE p.guid = :parent
+         ORDER BY b.position ASC`,
+        { parent: aParent }
+      );
+      for (let row of childRows) {
+        let id = row.getResultByName("id");
+        let position = row.getResultByName("position");
+        if (aResultArray.indexOf(id) != position) {
+          info("Expected order: " + aResultArray);
+          await PlacesTestUtils.dumpTable({
+            db,
+            table: "moz_bookmarks",
+            columns: ["id", "parent", "position"],
+          });
+          do_throw(`Unexpected bookmarks order for ${aParent}.`);
+        }
+      }
+
+      let parentRows = await db.executeCached(
+        `SELECT syncChangeCounter FROM moz_bookmarks
+         WHERE guid = :parent`,
+        { parent: aParent }
+      );
+      for (let row of parentRows) {
+        let actualChangeCounter = row.getResultByName("syncChangeCounter");
+        Assert.ok(actualChangeCounter > 0);
+      }
+    }
+
+    await check_order(
+      PlacesUtils.bookmarks.unfiledGuid,
+      this._unfiledBookmarks
+    );
+    await check_order(
+      PlacesUtils.bookmarks.toolbarGuid,
+      this._toolbarBookmarks
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "D.13",
+  desc: "Fix empty-named tags",
+  _taggedItemIds: {},
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    let placeId = await addPlace();
+    // Create a empty-named tag.
+    this._untitledTagId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.tagsGuid,
+      null,
+      ""
+    );
+    // Insert a bookmark in the tag, otherwise it will be removed.
+    let untitledTagGuid = await PlacesTestUtils.promiseItemGuid(
+      this._untitledTagId
+    );
+    await addBookmark(
+      placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      untitledTagGuid
+    );
+    // Create a empty-named folder.
+    this._untitledFolderId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      ""
+    );
+    // Create a titled tag.
+    this._titledTagId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.tagsGuid,
+      null,
+      "titledTag"
+    );
+    // Insert a bookmark in the tag, otherwise it will be removed.
+    let titledTagGuid = await PlacesTestUtils.promiseItemGuid(
+      this._titledTagId
+    );
+    await addBookmark(
+      placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      titledTagGuid
+    );
+    // Create a titled folder.
+    this._titledFolderId = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      "titledFolder"
+    );
+
+    // Create two tagged bookmarks in different folders.
+    this._taggedItemIds.inMenu = await addBookmark(
+      placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      PlacesUtils.bookmarks.menuGuid,
+      null,
+      "Tagged bookmark in menu"
+    );
+    this._taggedItemIds.inToolbar = await addBookmark(
+      placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      PlacesUtils.bookmarks.toolbarGuid,
+      null,
+      "Tagged bookmark in toolbar"
+    );
+  },
+
+  async check() {
+    // Check that valid bookmark is still there
+    let value = await PlacesTestUtils.getDatabaseValue(
+      "moz_bookmarks",
+      "title",
+      { id: this._untitledTagId }
+    );
+    Assert.equal(value, "(notitle)");
+    value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "title", {
+      id: this._untitledFolderId,
+    });
+    Assert.equal(value, "");
+    value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "title", {
+      id: this._titledTagId,
+    });
+    Assert.equal(value, "titledTag");
+    value = await PlacesTestUtils.getDatabaseValue("moz_bookmarks", "title", {
+      id: this._titledFolderId,
+    });
+    Assert.equal(value, "titledFolder");
+
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `SELECT syncChangeCounter FROM moz_bookmarks
+       WHERE id IN (:taggedInMenu, :taggedInToolbar)`,
+      {
+        taggedInMenu: this._taggedItemIds.inMenu,
+        taggedInToolbar: this._taggedItemIds.inToolbar,
+      }
+    );
+    for (let row of rows) {
+      Assert.greaterOrEqual(row.getResultByName("syncChangeCounter"), 1);
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "E.1",
+  desc: "Remove orphan icon entries",
+
+  _placeId: null,
+
+  async setup() {
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeTransaction(async () => {
+        // Insert favicon entries
+        await db.executeCached(
+          `INSERT INTO moz_icons (id, icon_url, fixed_icon_url_hash, root) VALUES(:favicon_id, :url, hash(fixup_url(:url)), :root)`,
+          [
+            {
+              favicon_id: 1,
+              url: "http://www1.mozilla.org/favicon.ico",
+              root: 0,
+            },
+            {
+              favicon_id: 2,
+              url: "http://www2.mozilla.org/favicon.ico",
+              root: 0,
+            },
+            {
+              favicon_id: 3,
+              url: "http://www3.mozilla.org/favicon.ico",
+              root: 1,
+            },
+          ]
+        );
+
+        // Insert orphan page.
+        await db.executeCached(
+          `INSERT INTO moz_pages_w_icons (id, page_url, page_url_hash)
+           VALUES(:page_id, :url, hash(:url))`,
+          { page_id: 99, url: "http://w99.mozilla.org/" }
+        );
+      });
+    });
+
+    // Insert a place using the existing favicon entry
+    this._placeId = await addPlace("http://www.mozilla.org", 1);
+  },
+
+  async check() {
+    // Check that used icon is still there
+    let value = await PlacesTestUtils.getDatabaseValue("moz_icons", "id", {
+      id: 1,
+    });
+    Assert.notStrictEqual(value, undefined);
+    // Check that unused icon has been removed
+    value = await PlacesTestUtils.getDatabaseValue("moz_icons", "id", {
+      id: 2,
+    });
+    Assert.strictEqual(value, undefined);
+    // Check that unused icon has been removed
+    value = await PlacesTestUtils.getDatabaseValue("moz_icons", "id", {
+      id: 3,
+    });
+    Assert.strictEqual(value, undefined);
+    // Check that the orphan page is gone.
+    value = await PlacesTestUtils.getDatabaseValue("moz_pages_w_icons", "id", {
+      id: 99,
+    });
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "F.1",
+  desc: "Remove orphan visits",
+
+  _placeId: null,
+  _invalidPlaceId: 1337,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Add a valid visit and an invalid one
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeCached(
+        `INSERT INTO moz_historyvisits(place_id)
+         VALUES (:place_id_1), (:place_id_2)`,
+        { place_id_1: this._placeId, place_id_2: this._invalidPlaceId }
+      );
+    });
+  },
+
+  async check() {
+    // Check that valid visit is still there
+    let value = await PlacesTestUtils.getDatabaseValue(
+      "moz_historyvisits",
+      "id",
+      {
+        place_id: this._placeId,
+      }
+    );
+    Assert.notStrictEqual(value, undefined);
+    // Check that invalid visit has been removed
+    value = await PlacesTestUtils.getDatabaseValue("moz_historyvisits", "id", {
+      place_id: this._invalidPlaceId,
+    });
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "G.1",
+  desc: "Remove orphan input history",
+
+  _placeId: null,
+  _invalidPlaceId: 1337,
+
+  async setup() {
+    // Add a place to ensure place_id = 1 is valid
+    this._placeId = await addPlace();
+    // Add input history entries
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeCached(
+        `INSERT INTO moz_inputhistory (place_id, input)
+         VALUES (:place_id_1, :input_1), (:place_id_2, :input_2)`,
+        {
+          place_id_1: this._placeId,
+          input_1: "moz",
+          place_id_2: this._invalidPlaceId,
+          input_2: "moz",
+        }
+      );
+    });
+  },
+
+  async check() {
+    // Check that inputhistory on valid place is still there
+    let value = await PlacesTestUtils.getDatabaseValue(
+      "moz_inputhistory",
+      "place_id",
+      { place_id: this._placeId }
+    );
+    Assert.notStrictEqual(value, undefined);
+    // Check that inputhistory on invalid place has gone
+    value = await PlacesTestUtils.getDatabaseValue(
+      "moz_inputhistory",
+      "place_id",
+      { place_id: this._invalidPlaceId }
+    );
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "I.1",
+  desc: "Remove unused keywords",
+
+  _bookmarkId: null,
+  _placeId: null,
+
+  async setup() {
+    // Insert 2 keywords
+    let bm = await PlacesUtils.bookmarks.insert({
+      url: "http://testkw.moz.org/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+    await PlacesUtils.keywords.insert({
+      url: bm.url,
+      keyword: "used",
+    });
+
+    await PlacesUtils.withConnectionWrapper("setup", async db => {
+      await db.executeCached(
+        `INSERT INTO moz_keywords (id, keyword, place_id)
+         VALUES(NULL, :keyword, :place_id)`,
+        { keyword: "unused", place_id: 100 }
+      );
+    });
+  },
+
+  async check() {
+    // Check that "used" keyword is still there
+    let value = await PlacesTestUtils.getDatabaseValue("moz_keywords", "id", {
+      keyword: "used",
+    });
+    Assert.notStrictEqual(value, undefined);
+    // Check that "unused" keyword has gone
+    value = await PlacesTestUtils.getDatabaseValue("moz_keywords", "id", {
+      keyword: "unused",
+    });
+    Assert.strictEqual(value, undefined);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.1",
+  desc: "remove duplicate URLs",
+  _placeA: -1,
+  _placeD: -1,
+  _placeE: -1,
+  _bookmarkIds: [],
+
+  async setup() {
+    // Place with visits, an autocomplete history entry, anno, and a bookmark.
+    this._placeA = await addPlace("http://example.com", null, "placeAAAAAAA");
+
+    // Duplicate Place with different visits and a keyword.
+    let placeB = await addPlace("http://example.com", null, "placeBBBBBBB");
+
+    // Another duplicate with conflicting autocomplete history entry and
+    // two more bookmarks.
+    let placeC = await addPlace("http://example.com", null, "placeCCCCCCC");
+
+    // Unrelated, unique Place.
+    this._placeD = await addPlace(
+      "http://example.net",
+      null,
+      "placeDDDDDDD",
+      1234
+    );
+
+    // Another unrelated Place, with the same hash as D, but different URL.
+    this._placeE = await addPlace(
+      "http://example.info",
+      null,
+      "placeEEEEEEE",
+      1234
+    );
+
+    let visits = [
+      {
+        placeId: this._placeA,
+        date: new Date(2017, 1, 2),
+        type: PlacesUtils.history.TRANSITIONS.LINK,
+      },
+      {
+        placeId: this._placeA,
+        date: new Date(2018, 3, 4),
+        type: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+      {
+        placeId: placeB,
+        date: new Date(2016, 5, 6),
+        type: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+      {
+        // Duplicate visit; should keep both when we merge.
+        placeId: placeB,
+        date: new Date(2018, 3, 4),
+        type: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+      {
+        placeId: this._placeD,
+        date: new Date(2018, 7, 8),
+        type: PlacesUtils.history.TRANSITIONS.LINK,
+      },
+      {
+        placeId: this._placeE,
+        date: new Date(2018, 8, 9),
+        type: PlacesUtils.history.TRANSITIONS.TYPED,
+      },
+    ];
+
+    let inputs = [
+      {
+        placeId: this._placeA,
+        input: "exam",
+        count: 4,
+      },
+      {
+        placeId: placeC,
+        input: "exam",
+        count: 3,
+      },
+      {
+        placeId: placeC,
+        input: "ex",
+        count: 5,
+      },
+      {
+        placeId: this._placeD,
+        input: "amp",
+        count: 3,
+      },
+    ];
+
+    let annos = [
+      {
+        name: "anno",
+        placeId: this._placeA,
+        content: "splish",
+      },
+      {
+        // Anno that's already set on A; should be ignored when we merge.
+        name: "anno",
+        placeId: placeB,
+        content: "oops",
+      },
+      {
+        name: "other-anno",
+        placeId: placeB,
+        content: "splash",
+      },
+      {
+        name: "other-anno",
+        placeId: this._placeD,
+        content: "sploosh",
+      },
+    ];
+
+    let bookmarks = [
+      {
+        placeId: this._placeA,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: "A",
+        guid: "bookmarkAAAA",
+      },
+      {
+        placeId: placeB,
+        parentGuid: PlacesUtils.bookmarks.mobileGuid,
+        title: "B",
+        guid: "bookmarkBBBB",
+      },
+      {
+        placeId: placeC,
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        title: "C1",
+        guid: "bookmarkCCC1",
+      },
+      {
+        placeId: placeC,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        title: "C2",
+        guid: "bookmarkCCC2",
+      },
+      {
+        placeId: this._placeD,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        title: "D",
+        guid: "bookmarkDDDD",
+      },
+      {
+        placeId: this._placeE,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        title: "E",
+        guid: "bookmarkEEEE",
+      },
+    ];
+
+    let keywords = [
+      {
+        placeId: placeB,
+        keyword: "hi",
+      },
+      {
+        placeId: this._placeD,
+        keyword: "bye",
+      },
+    ];
+
+    for (let { placeId, parentGuid, title, guid } of bookmarks) {
+      let itemId = await addBookmark(
+        placeId,
+        PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        parentGuid,
+        null,
+        title,
+        guid
+      );
+      this._bookmarkIds.push(itemId);
+    }
+
+    await PlacesUtils.withConnectionWrapper(
+      "L.1: Insert foreign key refs",
+      function (db) {
+        return db.executeTransaction(async function () {
+          for (let { placeId, date, type } of visits) {
+            await db.executeCached(
+              `INSERT INTO moz_historyvisits(place_id, visit_date, visit_type)
+               VALUES(:placeId, :date, :type)`,
+              { placeId, date: PlacesUtils.toPRTime(date), type }
+            );
+          }
+
+          for (let params of inputs) {
+            await db.executeCached(
+              `INSERT INTO moz_inputhistory(place_id, input, use_count)
+               VALUES(:placeId, :input, :count)`,
+              params
+            );
+          }
+
+          for (let { name, placeId, content } of annos) {
+            await db.executeCached(
+              `INSERT OR IGNORE INTO moz_anno_attributes(name)
+               VALUES(:name)`,
+              { name }
+            );
+
+            await db.executeCached(
+              `INSERT INTO moz_annos(place_id, anno_attribute_id, content)
+               VALUES(:placeId, (SELECT id FROM moz_anno_attributes
+                                 WHERE name = :name), :content)`,
+              { placeId, name, content }
+            );
+          }
+
+          for (let param of keywords) {
+            await db.executeCached(
+              `INSERT INTO moz_keywords(keyword, place_id)
+               VALUES(:keyword, :placeId)`,
+              param
+            );
+          }
+        });
+      }
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+
+    let placeRows = await db.execute(`
+      SELECT id, guid, foreign_count FROM moz_places
+      ORDER BY guid`);
+    let placeInfos = placeRows.map(row => ({
+      id: row.getResultByName("id"),
+      guid: row.getResultByName("guid"),
+      foreignCount: row.getResultByName("foreign_count"),
+    }));
+    Assert.deepEqual(
+      placeInfos,
+      [
+        {
+          id: this._placeA,
+          guid: "placeAAAAAAA",
+          foreignCount: 5, // 4 bookmarks + 1 keyword
+        },
+        {
+          id: this._placeD,
+          guid: "placeDDDDDDD",
+          foreignCount: 2, // 1 bookmark + 1 keyword
+        },
+        {
+          id: this._placeE,
+          guid: "placeEEEEEEE",
+          foreignCount: 1, // 1 bookmark
+        },
+      ],
+      "Should remove duplicate Places B and C"
+    );
+
+    let visitRows = await db.execute(`
+      SELECT place_id, visit_date, visit_type FROM moz_historyvisits
+      ORDER BY visit_date`);
+    let visitInfos = visitRows.map(row => ({
+      placeId: row.getResultByName("place_id"),
+      date: PlacesUtils.toDate(row.getResultByName("visit_date")),
+      type: row.getResultByName("visit_type"),
+    }));
+    Assert.deepEqual(
+      visitInfos,
+      [
+        {
+          placeId: this._placeA,
+          date: new Date(2016, 5, 6),
+          type: PlacesUtils.history.TRANSITIONS.TYPED,
+        },
+        {
+          placeId: this._placeA,
+          date: new Date(2017, 1, 2),
+          type: PlacesUtils.history.TRANSITIONS.LINK,
+        },
+        {
+          placeId: this._placeA,
+          date: new Date(2018, 3, 4),
+          type: PlacesUtils.history.TRANSITIONS.TYPED,
+        },
+        {
+          placeId: this._placeA,
+          date: new Date(2018, 3, 4),
+          type: PlacesUtils.history.TRANSITIONS.TYPED,
+        },
+        {
+          placeId: this._placeD,
+          date: new Date(2018, 7, 8),
+          type: PlacesUtils.history.TRANSITIONS.LINK,
+        },
+        {
+          placeId: this._placeE,
+          date: new Date(2018, 8, 9),
+          type: PlacesUtils.history.TRANSITIONS.TYPED,
+        },
+      ],
+      "Should merge history visits"
+    );
+
+    let inputRows = await db.execute(`
+      SELECT place_id, input, use_count FROM moz_inputhistory
+      ORDER BY use_count ASC`);
+    let inputInfos = inputRows.map(row => ({
+      placeId: row.getResultByName("place_id"),
+      input: row.getResultByName("input"),
+      count: row.getResultByName("use_count"),
+    }));
+    Assert.deepEqual(
+      inputInfos,
+      [
+        {
+          placeId: this._placeD,
+          input: "amp",
+          count: 3,
+        },
+        {
+          placeId: this._placeA,
+          input: "ex",
+          count: 5,
+        },
+        {
+          placeId: this._placeA,
+          input: "exam",
+          count: 7,
+        },
+      ],
+      "Should merge autocomplete history"
+    );
+
+    let annoRows = await db.execute(`
+      SELECT a.place_id, n.name, a.content FROM moz_annos a
+      JOIN moz_anno_attributes n ON n.id = a.anno_attribute_id
+      ORDER BY n.name, a.content ASC`);
+    let annoInfos = annoRows.map(row => ({
+      placeId: row.getResultByName("place_id"),
+      name: row.getResultByName("name"),
+      content: row.getResultByName("content"),
+    }));
+    Assert.deepEqual(
+      annoInfos,
+      [
+        {
+          placeId: this._placeA,
+          name: "anno",
+          content: "splish",
+        },
+        {
+          placeId: this._placeA,
+          name: "other-anno",
+          content: "splash",
+        },
+        {
+          placeId: this._placeD,
+          name: "other-anno",
+          content: "sploosh",
+        },
+      ],
+      "Should merge page annos"
+    );
+
+    let itemRows = await db.execute(
+      `
+      SELECT guid, fk, syncChangeCounter FROM moz_bookmarks
+      WHERE id IN (${new Array(this._bookmarkIds.length).fill("?").join(",")})
+      ORDER BY guid ASC`,
+      this._bookmarkIds
+    );
+    let itemInfos = itemRows.map(row => ({
+      guid: row.getResultByName("guid"),
+      placeId: row.getResultByName("fk"),
+      syncChangeCounter: row.getResultByName("syncChangeCounter"),
+    }));
+    Assert.deepEqual(
+      itemInfos,
+      [
+        {
+          guid: "bookmarkAAAA",
+          placeId: this._placeA,
+          syncChangeCounter: 1,
+        },
+        {
+          guid: "bookmarkBBBB",
+          placeId: this._placeA,
+          syncChangeCounter: 1,
+        },
+        {
+          guid: "bookmarkCCC1",
+          placeId: this._placeA,
+          syncChangeCounter: 1,
+        },
+        {
+          guid: "bookmarkCCC2",
+          placeId: this._placeA,
+          syncChangeCounter: 1,
+        },
+        {
+          guid: "bookmarkDDDD",
+          placeId: this._placeD,
+          syncChangeCounter: 0,
+        },
+        {
+          guid: "bookmarkEEEE",
+          placeId: this._placeE,
+          syncChangeCounter: 0,
+        },
+      ],
+      "Should merge bookmarks and bump change counter"
+    );
+
+    let keywordRows = await db.execute(`
+      SELECT keyword, place_id FROM moz_keywords
+      ORDER BY keyword ASC`);
+    let keywordInfos = keywordRows.map(row => ({
+      keyword: row.getResultByName("keyword"),
+      placeId: row.getResultByName("place_id"),
+    }));
+    Assert.deepEqual(
+      keywordInfos,
+      [
+        {
+          keyword: "bye",
+          placeId: this._placeD,
+        },
+        {
+          keyword: "hi",
+          placeId: this._placeA,
+        },
+      ],
+      "Should merge all keywords"
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.2",
+  desc: "Recalculate visit_count and last_visit_date",
+
+  async setup() {
+    async function setVisitCount(aURL, aValue) {
+      await PlacesUtils.withConnectionWrapper("setVisitCount", async db => {
+        await db.executeCached(
+          `UPDATE moz_places SET visit_count = :count
+           WHERE url_hash = hash(:url) AND url = :url`,
+          { count: aValue, url: aURL }
+        );
+      });
+    }
+    async function setLastVisitDate(aURL, aValue) {
+      await PlacesUtils.withConnectionWrapper("setVisitCount", async db => {
+        await db.executeCached(
+          `UPDATE moz_places SET last_visit_date = :date
+           WHERE url_hash = hash(:url) AND url = :url`,
+          { date: aValue, url: aURL }
+        );
+      });
+    }
+
+    let now = Date.now() * 1000;
+    // Add a page with 1 visit.
+    let url = "http://1.moz.org/";
+    await PlacesTestUtils.addVisits({ uri: uri(url), visitDate: now++ });
+    // Add a page with 1 visit and set wrong visit_count.
+    url = "http://2.moz.org/";
+    await PlacesTestUtils.addVisits({ uri: uri(url), visitDate: now++ });
+    await setVisitCount(url, 10);
+    // Add a page with 1 visit and set wrong last_visit_date.
+    url = "http://3.moz.org/";
+    await PlacesTestUtils.addVisits({ uri: uri(url), visitDate: now++ });
+    await setLastVisitDate(url, now++);
+    // Add a page with 1 visit and set wrong stats.
+    url = "http://4.moz.org/";
+    await PlacesTestUtils.addVisits({ uri: uri(url), visitDate: now++ });
+    await setVisitCount(url, 10);
+    await setLastVisitDate(url, now++);
+
+    // Add a page without visits.
+    url = "http://5.moz.org/";
+    await addPlace(url);
+    // Add a page without visits and set wrong visit_count.
+    url = "http://6.moz.org/";
+    await addPlace(url);
+    await setVisitCount(url, 10);
+    // Add a page without visits and set wrong last_visit_date.
+    url = "http://7.moz.org/";
+    await addPlace(url);
+    await setLastVisitDate(url, now++);
+    // Add a page without visits and set wrong stats.
+    url = "http://8.moz.org/";
+    await addPlace(url);
+    await setVisitCount(url, 10);
+    await setLastVisitDate(url, now++);
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      `SELECT h.id, h.last_visit_date as v_date
+       FROM moz_places h
+       LEFT JOIN moz_historyvisits v ON v.place_id = h.id AND visit_type NOT IN (0,4,7,8,9)
+       GROUP BY h.id HAVING h.visit_count <> count(v.id)
+       UNION ALL
+       SELECT h.id, MAX(v.visit_date) as v_date
+       FROM moz_places h
+       LEFT JOIN moz_historyvisits v ON v.place_id = h.id
+       GROUP BY h.id HAVING h.last_visit_date IS NOT v_date`
+    );
+    Assert.equal(rows.length, 0);
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.3",
+  desc: "recalculate hidden for redirects.",
+
+  async setup() {
+    await PlacesTestUtils.addVisits([
+      {
+        uri: NetUtil.newURI("http://l3.moz.org/"),
+        transition: TRANSITION_TYPED,
+      },
+      {
+        uri: NetUtil.newURI("http://l3.moz.org/redirecting/"),
+        transition: TRANSITION_TYPED,
+      },
+      {
+        uri: NetUtil.newURI("http://l3.moz.org/redirecting2/"),
+        transition: TRANSITION_REDIRECT_TEMPORARY,
+        referrer: NetUtil.newURI("http://l3.moz.org/redirecting/"),
+      },
+      {
+        uri: NetUtil.newURI("http://l3.moz.org/target/"),
+        transition: TRANSITION_REDIRECT_PERMANENT,
+        referrer: NetUtil.newURI("http://l3.moz.org/redirecting2/"),
+      },
+    ]);
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.executeCached(
+      "SELECT h.url FROM moz_places h WHERE h.hidden = 1"
+    );
+    Assert.equal(rows.length, 2);
+    for (let row of rows) {
+      let url = row.getResultByIndex(0);
+      Assert.ok(/redirecting/.test(url));
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.4",
+  desc: "recalculate foreign_count.",
+
+  async setup() {
+    this._pageGuid = (
+      await PlacesUtils.history.insert({
+        url: "http://l4.moz.org/",
+        visits: [{ date: new Date() }],
+      })
+    ).guid;
+    await PlacesUtils.bookmarks.insert({
+      url: "http://l4.moz.org/",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+    await PlacesUtils.keywords.insert({
+      url: "http://l4.moz.org/",
+      keyword: "kw",
+    });
+    Assert.equal(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "foreign_count", {
+        guid: this._pageGuid,
+      }),
+      2
+    );
+  },
+
+  async check() {
+    Assert.equal(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "foreign_count", {
+        guid: this._pageGuid,
+      }),
+      2
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.5",
+  desc: "recalculate hashes when missing.",
+
+  async setup() {
+    this._pageGuid = (
+      await PlacesUtils.history.insert({
+        url: "http://l5.moz.org/",
+        visits: [{ date: new Date() }],
+      })
+    ).guid;
+    Assert.greater(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "url_hash", {
+        guid: this._pageGuid,
+      }),
+      0
+    );
+    await PlacesUtils.withConnectionWrapper(
+      "change url hash",
+      async function (db) {
+        await db.execute(`UPDATE moz_places SET url_hash = 0`);
+      }
+    );
+    Assert.equal(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "url_hash", {
+        guid: this._pageGuid,
+      }),
+      0
+    );
+  },
+
+  async check() {
+    Assert.greater(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "url_hash", {
+        guid: this._pageGuid,
+      }),
+      0
+    );
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "L.6",
+  desc: "fix invalid Place GUIDs",
+  _placeIds: [],
+
+  async setup() {
+    let placeWithValidGuid = await addPlace(
+      "http://example.com/a",
+      null,
+      "placeAAAAAAA"
+    );
+    this._placeIds.push(placeWithValidGuid);
+
+    let placeWithEmptyGuid = await addPlace("http://example.com/b", null, "");
+    this._placeIds.push(placeWithEmptyGuid);
+
+    let placeWithoutGuid = await addPlace("http://example.com/c", null, null);
+    this._placeIds.push(placeWithoutGuid);
+
+    let placeWithInvalidGuid = await addPlace(
+      "http://example.com/c",
+      null,
+      "{123456}"
+    );
+    this._placeIds.push(placeWithInvalidGuid);
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let updatedRows = await db.execute(
+      `
+      SELECT id, guid
+      FROM moz_places
+      WHERE id IN (?, ?, ?, ?)`,
+      this._placeIds
+    );
+
+    for (let row of updatedRows) {
+      let id = row.getResultByName("id");
+      let guid = row.getResultByName("guid");
+      if (id == this._placeIds[0]) {
+        Assert.equal(guid, "placeAAAAAAA");
+      } else {
+        Assert.ok(PlacesUtils.isValidGuid(guid));
+      }
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "S.1",
+  desc: "fix invalid GUIDs for synced bookmarks",
+  _bookmarkInfos: [],
+
+  async setup() {
+    let folderWithInvalidGuid = await addBookmark(
+      null,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      PlacesUtils.bookmarks.menuGuid,
+      /* aKeywordId */ null,
+      "NORMAL folder with invalid GUID",
+      "{123456}",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+
+    let placeIdForBookmarkWithoutGuid = await addPlace();
+    let bookmarkWithoutGuid = await addBookmark(
+      placeIdForBookmarkWithoutGuid,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      "{123456}",
+      /* aKeywordId */ null,
+      "NEW bookmark without GUID",
+      /* aGuid */ null
+    );
+
+    let placeIdForBookmarkWithInvalidGuid = await addPlace();
+    let bookmarkWithInvalidGuid = await addBookmark(
+      placeIdForBookmarkWithInvalidGuid,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      "{123456}",
+      /* aKeywordId */ null,
+      "NORMAL bookmark with invalid GUID",
+      "bookmarkAAAA\n",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+
+    let placeIdForBookmarkWithValidGuid = await addPlace();
+    let bookmarkWithValidGuid = await addBookmark(
+      placeIdForBookmarkWithValidGuid,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      "{123456}",
+      /* aKeywordId */ null,
+      "NORMAL bookmark with valid GUID",
+      "bookmarkBBBB",
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    );
+
+    this._bookmarkInfos.push(
+      {
+        id: await PlacesTestUtils.promiseItemId(PlacesUtils.bookmarks.menuGuid),
+        syncChangeCounter: 1,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      },
+      {
+        id: folderWithInvalidGuid,
+        syncChangeCounter: 3,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      },
+      {
+        id: bookmarkWithoutGuid,
+        syncChangeCounter: 1,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      },
+      {
+        id: bookmarkWithInvalidGuid,
+        syncChangeCounter: 1,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      },
+      {
+        id: bookmarkWithValidGuid,
+        syncChangeCounter: 0,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      }
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let updatedRows = await db.execute(
+      `SELECT id, guid, syncChangeCounter, syncStatus
+       FROM moz_bookmarks
+       WHERE id IN (?, ?, ?, ?, ?)`,
+      this._bookmarkInfos.map(info => info.id)
+    );
+
+    for (let row of updatedRows) {
+      let id = row.getResultByName("id");
+      let guid = row.getResultByName("guid");
+      Assert.ok(PlacesUtils.isValidGuid(guid));
+
+      let cachedGuid = await PlacesTestUtils.promiseItemGuid(id);
+      Assert.equal(cachedGuid, guid);
+
+      let expectedInfo = this._bookmarkInfos.find(info => info.id == id);
+
+      let syncChangeCounter = row.getResultByName("syncChangeCounter");
+      Assert.equal(syncChangeCounter, expectedInfo.syncChangeCounter);
+
+      let syncStatus = row.getResultByName("syncStatus");
+      Assert.equal(syncStatus, expectedInfo.syncStatus);
+    }
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["bookmarkAAAA\n", "{123456}"]
+    );
+  },
+});
+
+tests.push({
+  name: "S.2",
+  desc: "drop tombstones for bookmarks that aren't deleted",
+
+  async setup() {
+    let placeId = await addPlace();
+    await addBookmark(
+      placeId,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      PlacesUtils.bookmarks.menuGuid,
+      null,
+      "",
+      "bookmarkAAAA"
+    );
+
+    await PlacesUtils.withConnectionWrapper("Insert tombstones", db =>
+      db.executeTransaction(async function () {
+        for (let guid of ["bookmarkAAAA", "bookmarkBBBB"]) {
+          await db.executeCached(
+            `INSERT INTO moz_bookmarks_deleted(guid)
+             VALUES(:guid)`,
+            { guid }
+          );
+        }
+      })
+    );
+  },
+
+  async check() {
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    Assert.deepEqual(
+      tombstones.map(info => info.guid),
+      ["bookmarkBBBB"]
+    );
+  },
+});
+
+tests.push({
+  name: "S.3",
+  desc: "set missing added and last modified dates",
+  _placeVisits: [],
+  _bookmarksWithDates: [],
+
+  async setup() {
+    let placeIdWithVisits = await addPlace();
+    let placeIdWithZeroVisit = await addPlace();
+    this._placeVisits.push(
+      {
+        placeId: placeIdWithVisits,
+        visitDate: PlacesUtils.toPRTime(new Date(2017, 9, 4)),
+      },
+      {
+        placeId: placeIdWithVisits,
+        visitDate: PlacesUtils.toPRTime(new Date(2017, 9, 8)),
+      },
+      {
+        placeId: placeIdWithZeroVisit,
+        visitDate: 0,
+      }
+    );
+
+    this._bookmarksWithDates.push(
+      {
+        guid: "bookmarkAAAA",
+        placeId: null,
+        parent: PlacesUtils.bookmarks.menuGuid,
+        dateAdded: null,
+        lastModified: PlacesUtils.toPRTime(new Date(2017, 9, 1)),
+      },
+      {
+        guid: "bookmarkBBBB",
+        placeId: null,
+        parent: PlacesUtils.bookmarks.menuGuid,
+        dateAdded: PlacesUtils.toPRTime(new Date(2017, 9, 2)),
+        lastModified: null,
+      },
+      {
+        guid: "bookmarkCCCC",
+        placeId: null,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        dateAdded: null,
+        lastModified: null,
+      },
+      {
+        guid: "bookmarkDDDD",
+        placeId: placeIdWithVisits,
+        parent: PlacesUtils.bookmarks.mobileGuid,
+        dateAdded: null,
+        lastModified: null,
+      },
+      {
+        guid: "bookmarkEEEE",
+        placeId: placeIdWithVisits,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        dateAdded: PlacesUtils.toPRTime(new Date(2017, 9, 3)),
+        lastModified: PlacesUtils.toPRTime(new Date(2017, 9, 6)),
+      },
+      {
+        guid: "bookmarkFFFF",
+        placeId: placeIdWithZeroVisit,
+        parent: PlacesUtils.bookmarks.unfiledGuid,
+        dateAdded: 0,
+        lastModified: 0,
+      }
+    );
+
+    await PlacesUtils.withConnectionWrapper(
+      "S.3: Insert bookmarks and visits",
+      db =>
+        db.executeTransaction(async () => {
+          await db.execute(
+            `INSERT INTO moz_historyvisits(place_id, visit_date)
+             VALUES(:placeId, :visitDate)`,
+            this._placeVisits
+          );
+
+          await db.execute(
+            `INSERT INTO moz_bookmarks(fk, type, parent, guid, dateAdded,
+                                       lastModified)
+             VALUES(:placeId, 1, (SELECT id FROM moz_bookmarks WHERE guid = :parent),
+                    :guid, :dateAdded, :lastModified)`,
+            this._bookmarksWithDates
+          );
+
+          await db.execute(
+            `UPDATE moz_bookmarks SET dateAdded = 0, lastModified = NULL
+             WHERE guid = :toolbarFolder`,
+            { toolbarFolder: PlacesUtils.bookmarks.toolbarGuid }
+          );
+        })
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let updatedRows = await db.execute(
+      `SELECT guid, dateAdded, lastModified
+       FROM moz_bookmarks
+       WHERE guid = :guid`,
+      [
+        { guid: PlacesUtils.bookmarks.toolbarGuid },
+        ...this._bookmarksWithDates.map(({ guid }) => ({ guid })),
+      ]
+    );
+
+    for (let row of updatedRows) {
+      let guid = row.getResultByName("guid");
+
+      let dateAdded = row.getResultByName("dateAdded");
+      Assert.ok(Number.isInteger(dateAdded));
+
+      let lastModified = row.getResultByName("lastModified");
+      Assert.ok(Number.isInteger(lastModified));
+
+      switch (guid) {
+        // Last modified date exists, so we should use it for date added.
+        case "bookmarkAAAA": {
+          let expectedInfo = this._bookmarksWithDates[0];
+          Assert.equal(dateAdded, expectedInfo.lastModified);
+          Assert.equal(lastModified, expectedInfo.lastModified);
+          break;
+        }
+
+        // Date added exists, so we should use it for last modified date.
+        case "bookmarkBBBB": {
+          let expectedInfo = this._bookmarksWithDates[1];
+          Assert.equal(dateAdded, expectedInfo.dateAdded);
+          Assert.equal(lastModified, expectedInfo.dateAdded);
+          break;
+        }
+
+        // C has no visits, date added, or last modified time, F has zeros for
+        // all, and the toolbar has a zero date added and no last modified time.
+        // In all cases, we should fall back to the current time.
+        case "bookmarkCCCC":
+        case "bookmarkFFFF":
+        case PlacesUtils.bookmarks.toolbarGuid: {
+          let nowAsPRTime = PlacesUtils.toPRTime(new Date());
+          Assert.greater(dateAdded, 0);
+          Assert.equal(dateAdded, lastModified);
+          Assert.ok(dateAdded <= nowAsPRTime);
+          break;
+        }
+
+        // Neither date added nor last modified exists, but we have two
+        // visits, so we should fall back to the earliest and latest visit
+        // dates.
+        case "bookmarkDDDD": {
+          let oldestVisit = this._placeVisits[0];
+          Assert.equal(dateAdded, oldestVisit.visitDate);
+          let newestVisit = this._placeVisits[1];
+          Assert.equal(lastModified, newestVisit.visitDate);
+          break;
+        }
+
+        // We have two visits, but both date added and last modified exist,
+        // so we shouldn't update them.
+        case "bookmarkEEEE": {
+          let expectedInfo = this._bookmarksWithDates[4];
+          Assert.equal(dateAdded, expectedInfo.dateAdded);
+          Assert.equal(lastModified, expectedInfo.lastModified);
+          break;
+        }
+
+        default:
+          throw new Error(`Unexpected row for bookmark ${guid}`);
+      }
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "S.4",
+  desc: "reset added dates that are ahead of last modified dates",
+  _bookmarksWithDates: [],
+
+  async setup() {
+    this._bookmarksWithDates.push({
+      guid: "bookmarkGGGG",
+      parent: PlacesUtils.bookmarks.unfiledGuid,
+      dateAdded: PlacesUtils.toPRTime(new Date(2017, 9, 6)),
+      lastModified: PlacesUtils.toPRTime(new Date(2017, 9, 3)),
+    });
+
+    await PlacesUtils.withConnectionWrapper(
+      "S.4: Insert bookmarks and visits",
+      db =>
+        db.executeTransaction(async () => {
+          await db.execute(
+            `INSERT INTO moz_bookmarks(type, parent, guid, dateAdded,
+                                       lastModified)
+             VALUES(1, (SELECT id FROM moz_bookmarks WHERE guid = :parent),
+                    :guid, :dateAdded, :lastModified)`,
+            this._bookmarksWithDates
+          );
+        })
+    );
+  },
+
+  async check() {
+    let db = await PlacesUtils.promiseDBConnection();
+    let updatedRows = await db.execute(
+      `SELECT guid, dateAdded, lastModified
+       FROM moz_bookmarks
+       WHERE guid = :guid`,
+      this._bookmarksWithDates.map(({ guid }) => ({ guid }))
+    );
+
+    for (let row of updatedRows) {
+      let guid = row.getResultByName("guid");
+      let dateAdded = row.getResultByName("dateAdded");
+      let lastModified = row.getResultByName("lastModified");
+      switch (guid) {
+        case "bookmarkGGGG": {
+          let expectedInfo = this._bookmarksWithDates[0];
+          Assert.equal(dateAdded, expectedInfo.lastModified);
+          Assert.equal(lastModified, expectedInfo.lastModified);
+          break;
+        }
+
+        default:
+          throw new Error(`Unexpected row for bookmark ${guid}`);
+      }
+    }
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+tests.push({
+  name: "Z",
+  desc: "Sanity: Preventive maintenance does not touch valid items",
+
+  _uri1: uri("http://www1.mozilla.org"),
+  _uri2: uri("http://www2.mozilla.org"),
+  _folder: null,
+  _bookmark: null,
+  _bookmarkId: null,
+  _separator: null,
+
+  async setup() {
+    // use valid api calls to create a bunch of items
+    await PlacesTestUtils.addVisits([{ uri: this._uri1 }, { uri: this._uri2 }]);
+
+    let bookmarks = await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.toolbarGuid,
+      children: [
+        {
+          title: "testfolder",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          children: [
+            {
+              title: "testbookmark",
+              url: this._uri1,
+            },
+          ],
+        },
+      ],
+    });
+
+    this._folder = bookmarks[0];
+    this._bookmark = bookmarks[1];
+    this._bookmarkId = await PlacesTestUtils.promiseItemId(bookmarks[1].guid);
+
+    this._separator = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    });
+
+    PlacesUtils.tagging.tagURI(this._uri1, ["testtag"]);
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      this._uri2,
+      SMALLPNG_DATA_URI,
+      false,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      null,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+    await PlacesUtils.keywords.insert({
+      url: this._uri1.spec,
+      keyword: "testkeyword",
+    });
+    await PlacesUtils.history.update({
+      url: this._uri2,
+      annotations: new Map([["anno", "anno"]]),
+    });
+  },
+
+  async check() {
+    // Check that all items are correct
+    let isVisited = await PlacesUtils.history.hasVisits(this._uri1);
+    Assert.ok(isVisited);
+    isVisited = await PlacesUtils.history.hasVisits(this._uri2);
+    Assert.ok(isVisited);
+
+    Assert.equal(
+      (await PlacesUtils.bookmarks.fetch(this._bookmark.guid)).url,
+      this._uri1.spec
+    );
+    let folder = await PlacesUtils.bookmarks.fetch(this._folder.guid);
+    Assert.equal(folder.index, 0);
+    Assert.equal(folder.type, PlacesUtils.bookmarks.TYPE_FOLDER);
+    Assert.equal(
+      (await PlacesUtils.bookmarks.fetch(this._separator.guid)).type,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR
+    );
+
+    Assert.equal(PlacesUtils.tagging.getTagsForURI(this._uri1).length, 1);
+    Assert.equal(
+      (await PlacesUtils.keywords.fetch({ url: this._uri1.spec })).keyword,
+      "testkeyword"
+    );
+    let pageInfo = await PlacesUtils.history.fetch(this._uri2, {
+      includeAnnotations: true,
+    });
+    Assert.equal(pageInfo.annotations.get("anno"), "anno");
+
+    await new Promise(resolve => {
+      PlacesUtils.favicons.getFaviconURLForPage(this._uri2, aFaviconURI => {
+        Assert.ok(aFaviconURI.equals(SMALLPNG_DATA_URI));
+        resolve();
+      });
+    });
+  },
+});
+
+// ------------------------------------------------------------------------------
+
+add_task(async function test_preventive_maintenance() {
+  let db = await PlacesUtils.promiseDBConnection();
+  // Get current bookmarks max ID for cleanup
+  defaultBookmarksMaxId = (
+    await db.executeCached("SELECT MAX(id) FROM moz_bookmarks")
+  )[0].getResultByIndex(0);
+  Assert.ok(defaultBookmarksMaxId > 0);
+
+  for (let test of tests) {
+    await PlacesTestUtils.markBookmarksAsSynced();
+
+    info("\nExecuting test: " + test.name + "\n*** " + test.desc + "\n");
+    await test.setup();
+
+    Services.prefs.clearUserPref("places.database.lastMaintenance");
+    await PlacesDBUtils.maintenanceOnIdle();
+
+    // Check the lastMaintenance time has been saved.
+    Assert.notEqual(
+      Services.prefs.getIntPref("places.database.lastMaintenance"),
+      null
+    );
+
+    await test.check();
+
+    await cleanDatabase();
+  }
+
+  // Sanity check: all roots should be intact
+  Assert.strictEqual(
+    (await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.rootGuid))
+      .parentGuid,
+    undefined
+  );
+  Assert.deepEqual(
+    (await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.menuGuid))
+      .parentGuid,
+    PlacesUtils.bookmarks.rootGuid
+  );
+  Assert.deepEqual(
+    (await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.tagsGuid))
+      .parentGuid,
+    PlacesUtils.bookmarks.rootGuid
+  );
+  Assert.deepEqual(
+    (await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.unfiledGuid))
+      .parentGuid,
+    PlacesUtils.bookmarks.rootGuid
+  );
+  Assert.deepEqual(
+    (await PlacesUtils.bookmarks.fetch(PlacesUtils.bookmarks.toolbarGuid))
+      .parentGuid,
+    PlacesUtils.bookmarks.rootGuid
+  );
+});
+
+// ------------------------------------------------------------------------------
+
+add_task(async function test_idle_daily() {
+  const { sinon } = ChromeUtils.importESModule(
+    "resource://testing-common/Sinon.sys.mjs"
+  );
+  const sandbox = sinon.createSandbox();
+  sandbox.stub(PlacesDBUtils, "maintenanceOnIdle");
+  Services.prefs.clearUserPref("places.database.lastMaintenance");
+  Cc["@mozilla.org/places/databaseUtilsIdleMaintenance;1"]
+    .getService(Ci.nsIObserver)
+    .observe(null, "idle-daily", "");
+  Assert.ok(
+    PlacesDBUtils.maintenanceOnIdle.calledOnce,
+    "maintenanceOnIdle was invoked"
+  );
+  sandbox.restore();
+});
diff --git a/toolkit/components/places/tests/maintenance/test_preventive_maintenance_checkAndFixDatabase.js b/toolkit/components/places/tests/maintenance/test_preventive_maintenance_checkAndFixDatabase.js
new file mode 100644
index 0000000000..0ff33bb3ba
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_preventive_maintenance_checkAndFixDatabase.js
@@ -0,0 +1,36 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test preventive maintenance checkAndFixDatabase.
+ */
+
+add_task(async function () {
+  // We must initialize places first, or we won't have a db to check.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CREATE
+  );
+
+  let tasksStatusMap = await PlacesDBUtils.checkAndFixDatabase();
+  let numberOfTasksRun = tasksStatusMap.size;
+  let successfulTasks = [];
+  let failedTasks = [];
+  tasksStatusMap.forEach(val => {
+    if (val.succeeded && val.logs) {
+      successfulTasks.push(val);
+    } else {
+      failedTasks.push(val);
+    }
+  });
+  Assert.equal(numberOfTasksRun, 6, "Check that we have run all tasks.");
+  Assert.equal(
+    successfulTasks.length,
+    6,
+    "Check that we have run all tasks successfully"
+  );
+  Assert.equal(failedTasks.length, 0, "Check that no task is failing");
+});
diff --git a/toolkit/components/places/tests/maintenance/test_preventive_maintenance_runTasks.js b/toolkit/components/places/tests/maintenance/test_preventive_maintenance_runTasks.js
new file mode 100644
index 0000000000..9d11199824
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/test_preventive_maintenance_runTasks.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test preventive maintenance runTasks.
+ */
+
+add_task(async function () {
+  let tasksStatusMap = await PlacesDBUtils.runTasks([
+    PlacesDBUtils.removeOldCorruptDBs,
+  ]);
+  let numberOfTasksRun = tasksStatusMap.size;
+  let successfulTasks = [];
+  let failedTasks = [];
+  tasksStatusMap.forEach(val => {
+    if (val.succeeded) {
+      successfulTasks.push(val);
+    } else {
+      failedTasks.push(val);
+    }
+  });
+
+  Assert.equal(numberOfTasksRun, 1, "Check that we have run all tasks.");
+  Assert.equal(
+    successfulTasks.length,
+    1,
+    "Check that we have run all tasks successfully"
+  );
+  Assert.equal(failedTasks.length, 0, "Check that no task is failing");
+});
diff --git a/toolkit/components/places/tests/maintenance/xpcshell.toml b/toolkit/components/places/tests/maintenance/xpcshell.toml
new file mode 100644
index 0000000000..bcb5246fbe
--- /dev/null
+++ b/toolkit/components/places/tests/maintenance/xpcshell.toml
@@ -0,0 +1,33 @@
+[DEFAULT]
+head = "head.js"
+firefox-appdir = "browser"
+support-files = [
+  "corruptDB.sqlite",
+  "corruptPayload.sqlite",
+]
+
+["test_corrupt_favicons.js"]
+
+["test_corrupt_favicons_schema.js"]
+
+["test_corrupt_places_schema.js"]
+
+["test_corrupt_telemetry.js"]
+
+["test_favicons_replaceOnStartup.js"]
+
+["test_favicons_replaceOnStartup_clone.js"]
+
+["test_integrity_replacement.js"]
+
+["test_places_purge_caches.js"]
+
+["test_places_replaceOnStartup.js"]
+
+["test_places_replaceOnStartup_clone.js"]
+
+["test_preventive_maintenance.js"]
+
+["test_preventive_maintenance_checkAndFixDatabase.js"]
+
+["test_preventive_maintenance_runTasks.js"]
diff --git a/toolkit/components/places/tests/migration/favicons_v41.sqlite b/toolkit/components/places/tests/migration/favicons_v41.sqlite
new file mode 100644
index 0000000000..a59d9d286f
--- /dev/null
+++ b/toolkit/components/places/tests/migration/favicons_v41.sqlite
diff --git a/toolkit/components/places/tests/migration/head_migration.js b/toolkit/components/places/tests/migration/head_migration.js
new file mode 100644
index 0000000000..a58aada16a
--- /dev/null
+++ b/toolkit/components/places/tests/migration/head_migration.js
@@ -0,0 +1,47 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+const CURRENT_SCHEMA_VERSION = Ci.nsINavHistoryService.DATABASE_SCHEMA_VERSION;
+const FIRST_UPGRADABLE_SCHEMA_VERSION = 52;
+
+async function assertAnnotationsRemoved(db, expectedAnnos) {
+  for (let anno of expectedAnnos) {
+    let rows = await db.execute(
+      `
+      SELECT id FROM moz_anno_attributes
+      WHERE name = :anno
+    `,
+      { anno }
+    );
+
+    Assert.equal(rows.length, 0, `${anno} should not exist in the database`);
+  }
+}
+
+async function assertNoOrphanAnnotations(db) {
+  let rows = await db.execute(`
+    SELECT item_id FROM moz_items_annos
+    WHERE item_id NOT IN (SELECT id from moz_bookmarks)
+  `);
+
+  Assert.equal(rows.length, 0, `Should have no orphan annotations.`);
+
+  rows = await db.execute(`
+    SELECT id FROM moz_anno_attributes
+    WHERE id NOT IN (SELECT id from moz_items_annos)
+  `);
+
+  Assert.equal(rows.length, 0, `Should have no orphan annotation attributes.`);
+}
diff --git a/toolkit/components/places/tests/migration/places_outdated.sqlite b/toolkit/components/places/tests/migration/places_outdated.sqlite
new file mode 100644
index 0000000000..2852a4cf97
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_outdated.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v52.sqlite b/toolkit/components/places/tests/migration/places_v52.sqlite
new file mode 100644
index 0000000000..f4d32f6c94
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v52.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v54.sqlite b/toolkit/components/places/tests/migration/places_v54.sqlite
new file mode 100644
index 0000000000..a203b28c10
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v54.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v66.sqlite b/toolkit/components/places/tests/migration/places_v66.sqlite
new file mode 100644
index 0000000000..9578ee11e6
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v66.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v68.sqlite b/toolkit/components/places/tests/migration/places_v68.sqlite
new file mode 100644
index 0000000000..414fa170ec
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v68.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v69.sqlite b/toolkit/components/places/tests/migration/places_v69.sqlite
new file mode 100644
index 0000000000..bc3053c18e
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v69.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v70.sqlite b/toolkit/components/places/tests/migration/places_v70.sqlite
new file mode 100644
index 0000000000..907e7f5046
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v70.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v72.sqlite b/toolkit/components/places/tests/migration/places_v72.sqlite
new file mode 100644
index 0000000000..59d0d8fdab
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v72.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v74.sqlite b/toolkit/components/places/tests/migration/places_v74.sqlite
new file mode 100644
index 0000000000..e7078a054f
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v74.sqlite
diff --git a/toolkit/components/places/tests/migration/places_v75.sqlite b/toolkit/components/places/tests/migration/places_v75.sqlite
new file mode 100644
index 0000000000..2dd624b945
--- /dev/null
+++ b/toolkit/components/places/tests/migration/places_v75.sqlite
diff --git a/toolkit/components/places/tests/migration/test_current_from_downgraded.js b/toolkit/components/places/tests/migration/test_current_from_downgraded.js
new file mode 100644
index 0000000000..5daec14e2f
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_downgraded.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures we can pass twice through migration methods without
+// failing, that is what happens in case of a downgrade followed by an upgrade.
+
+add_task(async function setup() {
+  let dbFile = PathUtils.join(
+    do_get_cwd().path,
+    `places_v${CURRENT_SCHEMA_VERSION}.sqlite`
+  );
+  Assert.ok(await IOUtils.exists(dbFile));
+  await setupPlacesDatabase(`places_v${CURRENT_SCHEMA_VERSION}.sqlite`);
+  // Downgrade the schema version to the first supported one.
+  let path = PathUtils.join(PathUtils.profileDir, DB_FILENAME);
+  let db = await Sqlite.openConnection({ path });
+  await db.setSchemaVersion(FIRST_UPGRADABLE_SCHEMA_VERSION);
+  await db.close();
+});
+
+add_task(async function database_is_valid() {
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_outdated.js b/toolkit/components/places/tests/migration/test_current_from_outdated.js
new file mode 100644
index 0000000000..e7fad5b3a4
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_outdated.js
@@ -0,0 +1,47 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests migration from a preliminary schema version 6 that
+ * lacks frecency column and moz_inputhistory table.
+ */
+
+add_task(async function setup() {
+  await setupPlacesDatabase("places_outdated.sqlite");
+});
+
+add_task(async function corrupt_database_not_exists() {
+  let corruptPath = PathUtils.join(
+    PathUtils.profileDir,
+    "places.sqlite.corrupt"
+  );
+  Assert.ok(
+    !(await IOUtils.exists(corruptPath)),
+    "Corrupt file should not exist"
+  );
+});
+
+add_task(async function database_is_valid() {
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_CORRUPT
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+});
+
+add_task(async function check_columns() {
+  // Check the database has been replaced, these would throw otherwise.
+  let db = await PlacesUtils.promiseDBConnection();
+  await db.execute("SELECT frecency from moz_places");
+  await db.execute("SELECT 1 from moz_inputhistory");
+});
+
+add_task(async function corrupt_database_exists() {
+  let corruptPath = PathUtils.join(
+    PathUtils.profileDir,
+    "places.sqlite.corrupt"
+  );
+  Assert.ok(await IOUtils.exists(corruptPath), "Corrupt file should exist");
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v53.js b/toolkit/components/places/tests/migration/test_current_from_v53.js
new file mode 100644
index 0000000000..ce7b31c8df
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v53.js
@@ -0,0 +1,23 @@
+add_task(async function setup() {
+  // Since this migration doesn't affect places.sqlite, we can reuse v43.
+  await setupPlacesDatabase("places_v52.sqlite");
+  await setupPlacesDatabase("favicons_v41.sqlite", "favicons.sqlite");
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+
+  let count = (
+    await db.execute(
+      `SELECT count(*) FROM moz_icons_to_pages WHERE expire_ms = 0`
+    )
+  )[0].getResultByIndex(0);
+  Assert.equal(count, 0, "All the expirations should be set");
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v54.js b/toolkit/components/places/tests/migration/test_current_from_v54.js
new file mode 100644
index 0000000000..94c8a26474
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v54.js
@@ -0,0 +1,58 @@
+add_task(async function setup() {
+  // Since this migration doesn't affect places.sqlite, we can reuse v43.
+  await setupPlacesDatabase("places_v54.sqlite");
+  await setupPlacesDatabase("favicons_v41.sqlite", "favicons.sqlite");
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+
+  for (let table of [
+    "moz_places_metadata",
+    "moz_places_metadata_search_queries",
+  ]) {
+    let count = (
+      await db.execute(`SELECT count(*) FROM ${table}`)
+    )[0].getResultByIndex(0);
+    Assert.equal(count, 0, `Empty table ${table}`);
+  }
+
+  for (let table of [
+    "moz_places_metadata_snapshots",
+    "moz_places_metadata_snapshots_extra",
+    "moz_places_metadata_snapshots_groups",
+    "moz_places_metadata_groups_to_snapshots",
+    "moz_session_metadata",
+    "moz_session_to_places",
+  ]) {
+    await Assert.rejects(
+      db.execute(`SELECT count(*) FROM ${table}`),
+      /no such table/,
+      `Table ${table} should not exist`
+    );
+  }
+});
+
+add_task(async function scrolling_fields_in_database() {
+  let db = await PlacesUtils.promiseDBConnection();
+  await db.execute(
+    `SELECT scrolling_time,scrolling_distance FROM moz_places_metadata`
+  );
+});
+
+add_task(async function site_name_field_in_database() {
+  let db = await PlacesUtils.promiseDBConnection();
+  await db.execute(`SELECT site_name FROM moz_places`);
+});
+
+add_task(async function previews_tombstones_in_database() {
+  let db = await PlacesUtils.promiseDBConnection();
+  await db.execute(`SELECT hash FROM moz_previews_tombstones`);
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v66.js b/toolkit/components/places/tests/migration/test_current_from_v66.js
new file mode 100644
index 0000000000..5ea14f3b9d
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v66.js
@@ -0,0 +1,53 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  const path = await setupPlacesDatabase("places_v66.sqlite");
+
+  const db = await Sqlite.openConnection({ path });
+  await db.execute(`
+    INSERT INTO moz_inputhistory (input, use_count, place_id)
+    VALUES
+      ('abc', 1, 1),
+      ('aBc', 0.9, 1),
+      ('ABC', 5, 1),
+      ('ABC', 1, 2),
+      ('DEF', 1, 3)
+  `);
+  await db.close();
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+});
+
+add_task(async function moz_inputhistory() {
+  await PlacesUtils.withConnectionWrapper("test_sqlite_migration", async db => {
+    const rows = await db.execute(
+      "SELECT * FROM moz_inputhistory ORDER BY place_id"
+    );
+
+    Assert.equal(rows.length, 3);
+
+    Assert.equal(rows[0].getResultByName("place_id"), 1);
+    Assert.equal(rows[0].getResultByName("input"), "abc");
+    Assert.equal(rows[0].getResultByName("use_count"), 5);
+
+    Assert.equal(rows[1].getResultByName("place_id"), 2);
+    Assert.equal(rows[1].getResultByName("input"), "abc");
+    Assert.equal(rows[1].getResultByName("use_count"), 1);
+
+    Assert.equal(rows[2].getResultByName("place_id"), 3);
+    Assert.equal(rows[2].getResultByName("input"), "def");
+    Assert.equal(rows[2].getResultByName("use_count"), 1);
+  });
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v68.js b/toolkit/components/places/tests/migration/test_current_from_v68.js
new file mode 100644
index 0000000000..689fcbfd40
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v68.js
@@ -0,0 +1,35 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  const path = await setupPlacesDatabase("places_v68.sqlite");
+
+  const db = await Sqlite.openConnection({ path });
+  await db.execute("INSERT INTO moz_historyvisits (from_visit) VALUES (-1)");
+  await db.close();
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  const db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+});
+
+add_task(async function moz_historyvisits() {
+  await PlacesUtils.withConnectionWrapper("test_sqlite_migration", async db => {
+    const rows = await db.execute(
+      "SELECT * FROM moz_historyvisits WHERE from_visit=-1"
+    );
+
+    Assert.equal(rows.length, 1);
+    Assert.equal(rows[0].getResultByName("source"), 0);
+    Assert.equal(rows[0].getResultByName("triggeringPlaceId"), null);
+  });
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v69.js b/toolkit/components/places/tests/migration/test_current_from_v69.js
new file mode 100644
index 0000000000..09c66fb66e
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v69.js
@@ -0,0 +1,84 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  const path = await setupPlacesDatabase("places_v69.sqlite");
+
+  const db = await Sqlite.openConnection({ path });
+  await db.execute(`
+    INSERT INTO moz_places (url, guid, url_hash, origin_id, frecency)
+    VALUES
+      ('https://test1.com', '___________1', '123456', 100, 0),
+      ('https://test2.com', '___________2', '123456', 101, -1),
+      ('https://test3.com', '___________3', '123456', 102, -1234)
+    `);
+  await db.execute(`
+    INSERT INTO moz_origins (id, prefix, host, frecency)
+    VALUES
+      (100, 'https://', 'test1.com', 0),
+      (101, 'https://', 'test2.com', 0),
+      (102, 'https://', 'test3.com', 0)
+    `);
+  await db.close();
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  const db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+});
+
+add_task(async function moz_historyvisits() {
+  await PlacesUtils.withConnectionWrapper("test_sqlite_migration", async db => {
+    function expectedFrecency(guid) {
+      switch (guid) {
+        case "___________1":
+          return 0;
+        case "___________2":
+          return -1;
+        case "___________3":
+          return 1234;
+        default:
+          throw new Error("Unknown guid");
+      }
+    }
+    const rows = await db.execute(
+      "SELECT guid, frecency FROM moz_places WHERE url_hash = '123456'"
+    );
+    for (let row of rows) {
+      Assert.equal(
+        row.getResultByName("frecency"),
+        expectedFrecency(row.getResultByName("guid")),
+        "Check expected frecency"
+      );
+    }
+    const origins = new Map(
+      (await db.execute("SELECT host, frecency FROM moz_origins")).map(r => [
+        r.getResultByName("host"),
+        r.getResultByName("frecency"),
+      ])
+    );
+    Assert.equal(origins.get("test1.com"), 0);
+    Assert.equal(origins.get("test2.com"), 0);
+    Assert.equal(origins.get("test3.com"), 1234);
+
+    const statSum = (
+      await db.execute(
+        "SELECT value FROM moz_meta WHERE key = 'origin_frecency_sum'"
+      )
+    )[0].getResultByName("value");
+    const sum = (
+      await db.execute(
+        "SELECT SUM(frecency) AS sum from moz_origins WHERE frecency > 0"
+      )
+    )[0].getResultByName("sum");
+    Assert.equal(sum, statSum, "Check stats were updated");
+  });
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v70.js b/toolkit/components/places/tests/migration/test_current_from_v70.js
new file mode 100644
index 0000000000..e5e41852e3
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v70.js
@@ -0,0 +1,96 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  let path = await setupPlacesDatabase("places_v70.sqlite");
+
+  let db = await Sqlite.openConnection({ path });
+  await db.execute(`
+    INSERT INTO moz_places (url, guid, url_hash, origin_id, frecency, foreign_count)
+    VALUES
+      ('https://test1.com', '___________1', '123456', 100, 0, 2),
+      ('https://test2.com', '___________2', '123456', 101, -1, 2),
+      ('https://test3.com', '___________3', '123456', 102, -1234, 1)
+    `);
+  await db.execute(`
+    INSERT INTO moz_origins (id, prefix, host, frecency)
+    VALUES
+      (100, 'https://', 'test1.com', 0),
+      (101, 'https://', 'test2.com', 0),
+      (102, 'https://', 'test3.com', 0)
+    `);
+  await db.execute(
+    `INSERT INTO moz_session_metadata
+      (id, guid)
+      VALUES (0, "0")
+    `
+  );
+
+  await db.execute(
+    `INSERT INTO moz_places_metadata_snapshots
+      (place_id, created_at, first_interaction_at, last_interaction_at)
+      VALUES ((SELECT id FROM moz_places WHERE guid = :guid), 0, 0, 0)
+    `,
+    { guid: "___________1" }
+  );
+  await db.execute(
+    `INSERT INTO moz_bookmarks
+      (fk, guid)
+      VALUES ((SELECT id FROM moz_places WHERE guid = :guid), :guid)
+    `,
+    { guid: "___________1" }
+  );
+
+  await db.execute(
+    `INSERT INTO moz_places_metadata_snapshots
+      (place_id, created_at, first_interaction_at, last_interaction_at)
+      VALUES ((SELECT id FROM moz_places WHERE guid = :guid), 0, 0, 0)
+    `,
+    { guid: "___________2" }
+  );
+  await db.execute(
+    `INSERT INTO moz_session_to_places
+      (session_id, place_id)
+      VALUES (0, (SELECT id FROM moz_places WHERE guid = :guid))
+    `,
+    { guid: "___________2" }
+  );
+
+  await db.execute(
+    `INSERT INTO moz_session_to_places
+      (session_id, place_id)
+      VALUES (0, (SELECT id FROM moz_places WHERE guid = :guid))
+    `,
+    { guid: "___________3" }
+  );
+
+  await db.close();
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  const db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+
+  let rows = await db.execute("SELECT guid, foreign_count FROM moz_places");
+  for (let row of rows) {
+    let guid = row.getResultByName("guid");
+    let count = row.getResultByName("foreign_count");
+    if (guid == "___________1") {
+      Assert.equal(count, 1, "test1 should have the correct foreign_count");
+    }
+    if (guid == "___________2") {
+      Assert.equal(count, 0, "test2 should have the correct foreign_count");
+    }
+    if (guid == "___________3") {
+      Assert.equal(count, 0, "test3 should have the correct foreign_count");
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v72.js b/toolkit/components/places/tests/migration/test_current_from_v72.js
new file mode 100644
index 0000000000..626279fce4
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v72.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  await setupPlacesDatabase("places_v72.sqlite");
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  const db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+
+  await db.execute(
+    "SELECT recalc_frecency, alt_frecency, recalc_alt_frecency FROM moz_origins"
+  );
+
+  await db.execute("SELECT alt_frecency, recalc_alt_frecency FROM moz_places");
+  Assert.ok(
+    await db.indexExists("moz_places_altfrecencyindex"),
+    "Should have created an index"
+  );
+});
diff --git a/toolkit/components/places/tests/migration/test_current_from_v74.js b/toolkit/components/places/tests/migration/test_current_from_v74.js
new file mode 100644
index 0000000000..82c535f78f
--- /dev/null
+++ b/toolkit/components/places/tests/migration/test_current_from_v74.js
@@ -0,0 +1,22 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  await setupPlacesDatabase("places_v74.sqlite");
+});
+
+add_task(async function database_is_valid() {
+  // Accessing the database for the first time triggers migration.
+  Assert.equal(
+    PlacesUtils.history.databaseStatus,
+    PlacesUtils.history.DATABASE_STATUS_UPGRADED
+  );
+
+  const db = await PlacesUtils.promiseDBConnection();
+  Assert.equal(await db.getSchemaVersion(), CURRENT_SCHEMA_VERSION);
+
+  await db.execute("SELECT * FROM moz_places_extra");
+  await db.execute("SELECT * from moz_historyvisits_extra");
+});
diff --git a/toolkit/components/places/tests/migration/xpcshell.toml b/toolkit/components/places/tests/migration/xpcshell.toml
new file mode 100644
index 0000000000..b127fa501f
--- /dev/null
+++ b/toolkit/components/places/tests/migration/xpcshell.toml
@@ -0,0 +1,38 @@
+[DEFAULT]
+head = "head_migration.js"
+skip-if = ["condprof"] # Not worth running conditioned profiles on these migration
+# tests for databases. See discussion in bug 1838791.
+
+support-files = [
+  "favicons_v41.sqlite",
+  "places_outdated.sqlite",
+  "places_v52.sqlite",
+  "places_v54.sqlite",
+  "places_v66.sqlite",
+  "places_v68.sqlite",
+  "places_v69.sqlite",
+  "places_v70.sqlite",
+  "places_v72.sqlite",
+  "places_v74.sqlite",
+  "places_v75.sqlite",
+]
+
+["test_current_from_downgraded.js"]
+
+["test_current_from_outdated.js"]
+
+["test_current_from_v53.js"]
+
+["test_current_from_v54.js"]
+
+["test_current_from_v66.js"]
+
+["test_current_from_v68.js"]
+
+["test_current_from_v69.js"]
+
+["test_current_from_v70.js"]
+
+["test_current_from_v72.js"]
+
+["test_current_from_v74.js"]
diff --git a/toolkit/components/places/tests/moz.build b/toolkit/components/places/tests/moz.build
new file mode 100644
index 0000000000..60c57f53b8
--- /dev/null
+++ b/toolkit/components/places/tests/moz.build
@@ -0,0 +1,77 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+TEST_DIRS += ["gtest"]
+
+TESTING_JS_MODULES += [
+    "PlacesTestUtils.sys.mjs",
+]
+
+XPCSHELL_TESTS_MANIFESTS += [
+    "bookmarks/xpcshell.toml",
+    "expiration/xpcshell.toml",
+    "favicons/xpcshell.toml",
+    "history/xpcshell.toml",
+    "legacy/xpcshell.toml",
+    "maintenance/xpcshell.toml",
+    "migration/xpcshell.toml",
+    "queries/xpcshell.toml",
+    "sync/xpcshell.toml",
+    "unit/xpcshell.toml",
+]
+
+BROWSER_CHROME_MANIFESTS += [
+    "browser/browser.toml",
+    "browser/previews/browser.toml",
+]
+
+MOCHITEST_CHROME_MANIFESTS += [
+    "chrome/chrome.toml",
+]
+
+TEST_HARNESS_FILES.xpcshell.toolkit.components.places.tests += [
+    "head_common.js",
+]
+
+TEST_HARNESS_FILES.testing.mochitest.tests.toolkit.components.places.tests.browser += [
+    "browser/1601563-1.html",
+    "browser/1601563-2.html",
+    "browser/399606-history.go-0.html",
+    "browser/399606-httprefresh.html",
+    "browser/399606-location.reload.html",
+    "browser/399606-location.replace.html",
+    "browser/399606-window.location.href.html",
+    "browser/399606-window.location.html",
+    "browser/461710_link_page-2.html",
+    "browser/461710_link_page-3.html",
+    "browser/461710_link_page.html",
+    "browser/461710_visited_page.html",
+    "browser/begin.html",
+    "browser/favicon-normal16.png",
+    "browser/favicon-normal32.png",
+    "browser/favicon.html",
+    "browser/final.html",
+    "browser/history_post.html",
+    "browser/history_post.sjs",
+    "browser/redirect-target.html",
+    "browser/redirect.sjs",
+    "browser/redirect_once.sjs",
+    "browser/redirect_self.sjs",
+    "browser/redirect_thrice.sjs",
+    "browser/redirect_twice.sjs",
+    "browser/redirect_twice_perma.sjs",
+    "browser/title1.html",
+    "browser/title2.html",
+]
+
+TEST_HARNESS_FILES.testing.mochitest.tests.toolkit.components.places.tests.chrome += [
+    "chrome/bad_links.atom",
+    "chrome/link-less-items-no-site-uri.rss",
+    "chrome/link-less-items.rss",
+    "chrome/rss_as_html.rss",
+    "chrome/rss_as_html.rss^headers^",
+    "chrome/sample_feed.atom",
+]
diff --git a/toolkit/components/places/tests/queries/head_queries.js b/toolkit/components/places/tests/queries/head_queries.js
new file mode 100644
index 0000000000..ebb6eb4455
--- /dev/null
+++ b/toolkit/components/places/tests/queries/head_queries.js
@@ -0,0 +1,342 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+// Some Useful Date constants - PRTime uses microseconds, so convert
+const DAY_MICROSEC = 86400000000;
+const today = PlacesUtils.toPRTime(Date.now());
+const yesterday = today - DAY_MICROSEC;
+const lastweek = today - DAY_MICROSEC * 7;
+const daybefore = today - DAY_MICROSEC * 2;
+const old = today - DAY_MICROSEC * 3;
+const futureday = today + DAY_MICROSEC * 3;
+const olderthansixmonths = today - DAY_MICROSEC * 31 * 7;
+
+/**
+ * Generalized function to pull in an array of objects of data and push it into
+ * the database.  It does NOT do any checking to see that the input is
+ * appropriate.  This function is an asynchronous task, it can be called using
+ * "Task.spawn" or using the "yield" function inside another task.
+ */
+async function task_populateDB(aArray) {
+  // Iterate over aArray and execute all instructions.
+  for (let arrayItem of aArray) {
+    try {
+      // make the data object into a query data object in order to create proper
+      // default values for anything left unspecified
+      var qdata = new queryData(arrayItem);
+      if (qdata.isVisit) {
+        // Then we should add a visit for this node
+        await PlacesTestUtils.addVisits({
+          uri: uri(qdata.uri),
+          transition: qdata.transType,
+          visitDate: qdata.lastVisit,
+          referrer: qdata.referrer ? uri(qdata.referrer) : null,
+          title: qdata.title,
+        });
+        if (qdata.visitCount && !qdata.isDetails) {
+          // Set a fake visit_count, this is not a real count but can be used
+          // to test sorting by visit_count.
+          await PlacesTestUtils.updateDatabaseValues(
+            "moz_places",
+            { visit_count: qdata.visitCount },
+            { url: qdata.uri }
+          );
+        }
+      }
+
+      if (qdata.isRedirect) {
+        // This must be async to properly enqueue after the updateFrecency call
+        // done by the visit addition.
+        await PlacesTestUtils.updateDatabaseValues(
+          "moz_places",
+          { hidden: 1 },
+          { url: qdata.uri }
+        );
+      }
+
+      if (qdata.isDetails) {
+        // Then we add extraneous page details for testing
+        await PlacesTestUtils.addVisits({
+          uri: uri(qdata.uri),
+          visitDate: qdata.lastVisit,
+          title: qdata.title,
+        });
+      }
+
+      if (qdata.markPageAsTyped) {
+        PlacesUtils.history.markPageAsTyped(uri(qdata.uri));
+      }
+
+      if (qdata.isPageAnnotation) {
+        await PlacesUtils.history.update({
+          url: qdata.uri,
+          annotations: new Map([
+            [qdata.annoName, qdata.removeAnnotation ? null : qdata.annoVal],
+          ]),
+        });
+      }
+
+      if (qdata.isFolder) {
+        await PlacesUtils.bookmarks.insert({
+          parentGuid: qdata.parentGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          title: qdata.title,
+          index: qdata.index,
+        });
+      }
+
+      if (qdata.isBookmark) {
+        let data = {
+          parentGuid: qdata.parentGuid,
+          index: qdata.index,
+          title: qdata.title,
+          url: qdata.uri,
+        };
+
+        if (qdata.dateAdded) {
+          data.dateAdded = new Date(qdata.dateAdded / 1000);
+        }
+
+        if (qdata.lastModified) {
+          data.lastModified = new Date(qdata.lastModified / 1000);
+        }
+
+        await PlacesUtils.bookmarks.insert(data);
+
+        if (qdata.keyword) {
+          await PlacesUtils.keywords.insert({
+            url: qdata.uri,
+            keyword: qdata.keyword,
+          });
+        }
+      }
+
+      if (qdata.isTag) {
+        PlacesUtils.tagging.tagURI(uri(qdata.uri), qdata.tagArray);
+      }
+
+      if (qdata.isSeparator) {
+        await PlacesUtils.bookmarks.insert({
+          parentGuid: qdata.parentGuid,
+          type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          index: qdata.index,
+        });
+      }
+    } catch (ex) {
+      // use the arrayItem object here in case instantiation of qdata failed
+      info("Problem with this URI: " + arrayItem.uri);
+      do_throw("Error creating database: " + ex + "\n");
+    }
+  }
+}
+
+/**
+ * The Query Data Object - this object encapsulates data for our queries and is
+ * used to parameterize our calls to the Places APIs to put data into the
+ * database. It also has some interesting meta functions to determine which APIs
+ * should be called, and to determine if this object should show up in the
+ * resulting query.
+ * Its parameter is an object specifying which attributes you want to set.
+ * For ex:
+ * var myobj = new queryData({isVisit: true, uri:"http://mozilla.com", title="foo"});
+ * Note that it doesn't do any input checking on that object.
+ */
+function queryData(obj) {
+  this.isVisit = obj.isVisit ? obj.isVisit : false;
+  this.isBookmark = obj.isBookmark ? obj.isBookmark : false;
+  this.uri = obj.uri ? obj.uri : "";
+  this.lastVisit = obj.lastVisit ? obj.lastVisit : today;
+  this.referrer = obj.referrer ? obj.referrer : null;
+  this.transType = obj.transType
+    ? obj.transType
+    : Ci.nsINavHistoryService.TRANSITION_TYPED;
+  this.isRedirect = obj.isRedirect ? obj.isRedirect : false;
+  this.isDetails = obj.isDetails ? obj.isDetails : false;
+  this.title = obj.title ? obj.title : "";
+  this.markPageAsTyped = obj.markPageAsTyped ? obj.markPageAsTyped : false;
+  this.isPageAnnotation = obj.isPageAnnotation ? obj.isPageAnnotation : false;
+  this.removeAnnotation = !!obj.removeAnnotation;
+  this.annoName = obj.annoName ? obj.annoName : "";
+  this.annoVal = obj.annoVal ? obj.annoVal : "";
+  this.itemId = obj.itemId ? obj.itemId : 0;
+  this.annoMimeType = obj.annoMimeType ? obj.annoMimeType : "";
+  this.isTag = obj.isTag ? obj.isTag : false;
+  this.tagArray = obj.tagArray ? obj.tagArray : null;
+  this.parentGuid = obj.parentGuid || PlacesUtils.bookmarks.unfiledGuid;
+  this.feedURI = obj.feedURI ? obj.feedURI : "";
+  this.index = obj.index ? obj.index : PlacesUtils.bookmarks.DEFAULT_INDEX;
+  this.isFolder = obj.isFolder ? obj.isFolder : false;
+  this.contractId = obj.contractId ? obj.contractId : "";
+  this.lastModified = obj.lastModified ? obj.lastModified : null;
+  this.dateAdded = obj.dateAdded ? obj.dateAdded : null;
+  this.keyword = obj.keyword ? obj.keyword : "";
+  this.visitCount = obj.visitCount ? obj.visitCount : 0;
+  this.isSeparator = obj.hasOwnProperty("isSeparator") && obj.isSeparator;
+
+  // And now, the attribute for whether or not this object should appear in the
+  // resulting query
+  this.isInQuery = obj.isInQuery ? obj.isInQuery : false;
+}
+
+// All attributes are set in the constructor above
+queryData.prototype = {};
+
+/**
+ * Helper function to compare an array of query objects with a result set.
+ * It assumes the array of query objects contains the SAME SORT as the result
+ * set.  It checks the the uri, title, time, and bookmarkIndex properties of
+ * the results, where appropriate.
+ */
+function compareArrayToResult(aArray, aRoot) {
+  info("Comparing Array to Results");
+
+  var wasOpen = aRoot.containerOpen;
+  if (!wasOpen) {
+    aRoot.containerOpen = true;
+  }
+
+  // check expected number of results against actual
+  var expectedResultCount = aArray.filter(function (aEl) {
+    return aEl.isInQuery;
+  }).length;
+  if (expectedResultCount != aRoot.childCount) {
+    // Debugging code for failures.
+    dump_table("moz_places");
+    dump_table("moz_historyvisits");
+    info("Found children:");
+    for (let i = 0; i < aRoot.childCount; i++) {
+      info(aRoot.getChild(i).uri);
+    }
+    info("Expected:");
+    for (let i = 0; i < aArray.length; i++) {
+      if (aArray[i].isInQuery) {
+        info(aArray[i].uri);
+      }
+    }
+  }
+  Assert.equal(expectedResultCount, aRoot.childCount);
+
+  var inQueryIndex = 0;
+  for (var i = 0; i < aArray.length; i++) {
+    if (aArray[i].isInQuery) {
+      var child = aRoot.getChild(inQueryIndex);
+      // do_print("testing testData[" + i + "] vs result[" + inQueryIndex + "]");
+      if (!aArray[i].isFolder && !aArray[i].isSeparator) {
+        info(
+          "testing testData[" + aArray[i].uri + "] vs result[" + child.uri + "]"
+        );
+        if (aArray[i].uri != child.uri) {
+          dump_table("moz_places");
+          do_throw("Expected " + aArray[i].uri + " found " + child.uri);
+        }
+      }
+      if (!aArray[i].isSeparator && aArray[i].title != child.title) {
+        do_throw("Expected " + aArray[i].title + " found " + child.title);
+      }
+      if (
+        aArray[i].hasOwnProperty("lastVisit") &&
+        aArray[i].lastVisit != child.time
+      ) {
+        do_throw("Expected " + aArray[i].lastVisit + " found " + child.time);
+      }
+      if (
+        aArray[i].hasOwnProperty("index") &&
+        aArray[i].index != PlacesUtils.bookmarks.DEFAULT_INDEX &&
+        aArray[i].index != child.bookmarkIndex
+      ) {
+        do_throw(
+          "Expected " + aArray[i].index + " found " + child.bookmarkIndex
+        );
+      }
+
+      inQueryIndex++;
+    }
+  }
+
+  if (!wasOpen) {
+    aRoot.containerOpen = false;
+  }
+  info("Comparing Array to Results passes");
+}
+
+/**
+ * Helper function to check to see if one object either is or is not in the
+ * result set.  It can accept either a queryData object or an array of queryData
+ * objects.  If it gets an array, it only compares the first object in the array
+ * to see if it is in the result set.
+ * @returns {nsINavHistoryResultNode}: Either the node, if found, or null.
+ *          If input is an array, returns a result only for the first node.
+ *          To compare entire array, use the function above.
+ */
+function nodeInResult(aQueryData, aRoot) {
+  var rv = null;
+  var uri;
+  var wasOpen = aRoot.containerOpen;
+  if (!wasOpen) {
+    aRoot.containerOpen = true;
+  }
+
+  // If we have an array, pluck out the first item. If an object, pluc out the
+  // URI, we just compare URI's here.
+  if ("uri" in aQueryData) {
+    uri = aQueryData.uri;
+  } else {
+    uri = aQueryData[0].uri;
+  }
+
+  for (var i = 0; i < aRoot.childCount; i++) {
+    let node = aRoot.getChild(i);
+    if (uri == node.uri) {
+      rv = node;
+      break;
+    }
+  }
+  if (!wasOpen) {
+    aRoot.containerOpen = false;
+  }
+  return rv;
+}
+
+/**
+ * A nice helper function for debugging things. It prints the contents of a
+ * result set.
+ */
+function displayResultSet(aRoot) {
+  var wasOpen = aRoot.containerOpen;
+  if (!wasOpen) {
+    aRoot.containerOpen = true;
+  }
+
+  if (!aRoot.hasChildren) {
+    // Something wrong? Empty result set?
+    info("Result Set Empty");
+    return;
+  }
+
+  for (var i = 0; i < aRoot.childCount; ++i) {
+    info(
+      "Result Set URI: " +
+        aRoot.getChild(i).uri +
+        "   Title: " +
+        aRoot.getChild(i).title +
+        "   Visit Time: " +
+        aRoot.getChild(i).time
+    );
+  }
+  if (!wasOpen) {
+    aRoot.containerOpen = false;
+  }
+}
diff --git a/toolkit/components/places/tests/queries/readme.txt b/toolkit/components/places/tests/queries/readme.txt
new file mode 100644
index 0000000000..19414f96ed
--- /dev/null
+++ b/toolkit/components/places/tests/queries/readme.txt
@@ -0,0 +1,16 @@
+These are tests specific to the Places Query API.
+
+We are tracking the coverage of these tests here:
+http://wiki.mozilla.org/QA/TDAI/Projects/Places_Tests
+
+When creating one of these tests, you need to update those tables so that we
+know how well our test coverage is of this area.  Furthermore, when adding tests
+ensure to cover live update (changing the query set) by performing the following
+operations on the query set you get after running the query:
+* Adding a new item to the query set
+* Updating an existing item so that it matches the query set
+* Change an existing item so that it does not match the query set
+* Do multiple of the above inside an Update Batch transaction.
+* Try these transactions in different orders.
+
+Use the stub test to help you create a test with the proper structure.
diff --git a/toolkit/components/places/tests/queries/test_async.js b/toolkit/components/places/tests/queries/test_async.js
new file mode 100644
index 0000000000..8e895748ab
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_async.js
@@ -0,0 +1,379 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var tests = [
+  {
+    desc:
+      "nsNavHistoryFolderResultNode: Basic test, asynchronously open and " +
+      "close container with a single child",
+
+    loading(node, newState, oldState) {
+      this.checkStateChanged("loading", 1);
+      this.checkArgs("loading", node, oldState, node.STATE_CLOSED);
+    },
+
+    opened(node, newState, oldState) {
+      this.checkStateChanged("opened", 1);
+      this.checkState("loading", 1);
+      this.checkArgs("opened", node, oldState, node.STATE_LOADING);
+
+      print("Checking node children");
+      compareArrayToResult(this.data, node);
+
+      print("Closing container");
+      node.containerOpen = false;
+    },
+
+    closed(node, newState, oldState) {
+      this.checkStateChanged("closed", 1);
+      this.checkState("opened", 1);
+      this.checkArgs("closed", node, oldState, node.STATE_OPENED);
+      this.success();
+    },
+  },
+
+  {
+    desc:
+      "nsNavHistoryFolderResultNode: After async open and no changes, " +
+      "second open should be synchronous",
+
+    loading(node, newState, oldState) {
+      this.checkStateChanged("loading", 1);
+      this.checkState("closed", 0);
+      this.checkArgs("loading", node, oldState, node.STATE_CLOSED);
+    },
+
+    opened(node, newState, oldState) {
+      let cnt = this.checkStateChanged("opened", 1, 2);
+      let expectOldState = cnt === 1 ? node.STATE_LOADING : node.STATE_CLOSED;
+      this.checkArgs("opened", node, oldState, expectOldState);
+
+      print("Checking node children");
+      compareArrayToResult(this.data, node);
+
+      print("Closing container");
+      node.containerOpen = false;
+    },
+
+    closed(node, newState, oldState) {
+      let cnt = this.checkStateChanged("closed", 1, 2);
+      this.checkArgs("closed", node, oldState, node.STATE_OPENED);
+
+      switch (cnt) {
+        case 1:
+          node.containerOpen = true;
+          break;
+        case 2:
+          this.success();
+          break;
+      }
+    },
+  },
+
+  {
+    desc:
+      "nsNavHistoryFolderResultNode: After closing container in " +
+      "loading(), opened() should not be called",
+
+    loading(node, newState, oldState) {
+      this.checkStateChanged("loading", 1);
+      this.checkArgs("loading", node, oldState, node.STATE_CLOSED);
+      print("Closing container");
+      node.containerOpen = false;
+    },
+
+    opened(node, newState, oldState) {
+      do_throw("opened should not be called");
+    },
+
+    closed(node, newState, oldState) {
+      this.checkStateChanged("closed", 1);
+      this.checkState("loading", 1);
+      this.checkArgs("closed", node, oldState, node.STATE_LOADING);
+      this.success();
+    },
+  },
+];
+
+/**
+ * Instances of this class become the prototypes of the test objects above.
+ * Each test can therefore use the methods of this class, or they can override
+ * them if they want.  To run a test, call setup() and then run().
+ */
+function Test() {
+  // This maps a state name to the number of times it's been observed.
+  this.stateCounts = {};
+  // Promise object resolved when the next test can be run.
+  this.deferNextTest = Promise.withResolvers();
+}
+
+Test.prototype = {
+  /**
+   * Call this when an observer observes a container state change to sanity
+   * check the arguments.
+   *
+   * @param aNewState
+   *        The name of the new state.  Used only for printing out helpful info.
+   * @param aNode
+   *        The node argument passed to containerStateChanged.
+   * @param aOldState
+   *        The old state argument passed to containerStateChanged.
+   * @param aExpectOldState
+   *        The expected old state.
+   */
+  checkArgs(aNewState, aNode, aOldState, aExpectOldState) {
+    print("Node passed on " + aNewState + " should be result.root");
+    Assert.equal(this.result.root, aNode);
+    print("Old state passed on " + aNewState + " should be " + aExpectOldState);
+
+    // aOldState comes from xpconnect and will therefore be defined.  It may be
+    // zero, though, so use strict equality just to make sure aExpectOldState is
+    // also defined.
+    Assert.ok(aOldState === aExpectOldState);
+  },
+
+  /**
+   * Call this when an observer observes a container state change.  It registers
+   * the state change and ensures that it has been observed the given number
+   * of times.  See checkState for parameter explanations.
+   *
+   * @return The number of times aState has been observed, including the new
+   *         observation.
+   */
+  checkStateChanged(aState, aExpectedMin, aExpectedMax) {
+    print(aState + " state change observed");
+    if (!this.stateCounts.hasOwnProperty(aState)) {
+      this.stateCounts[aState] = 0;
+    }
+    this.stateCounts[aState]++;
+    return this.checkState(aState, aExpectedMin, aExpectedMax);
+  },
+
+  /**
+   * Ensures that the state has been observed the given number of times.
+   *
+   * @param  aState
+   *         The name of the state.
+   * @param  aExpectedMin
+   *         The state must have been observed at least this number of times.
+   * @param  aExpectedMax
+   *         The state must have been observed at most this number of times.
+   *         This parameter is optional.  If undefined, it's set to
+   *         aExpectedMin.
+   * @return The number of times aState has been observed, including the new
+   *         observation.
+   */
+  checkState(aState, aExpectedMin, aExpectedMax) {
+    let cnt = this.stateCounts[aState] || 0;
+    if (aExpectedMax === undefined) {
+      aExpectedMax = aExpectedMin;
+    }
+    if (aExpectedMin === aExpectedMax) {
+      print(
+        aState +
+          " should be observed only " +
+          aExpectedMin +
+          " times (actual = " +
+          cnt +
+          ")"
+      );
+    } else {
+      print(
+        aState +
+          " should be observed at least " +
+          aExpectedMin +
+          " times and at most " +
+          aExpectedMax +
+          " times (actual = " +
+          cnt +
+          ")"
+      );
+    }
+    Assert.ok(cnt >= aExpectedMin && cnt <= aExpectedMax);
+    return cnt;
+  },
+
+  /**
+   * Asynchronously opens the root of the test's result.
+   */
+  openContainer() {
+    // Set up the result observer.  It delegates to this object's callbacks and
+    // wraps them in a try-catch so that errors don't get eaten.
+    let self = this;
+    this.observer = {
+      containerStateChanged(container, oldState, newState) {
+        print(
+          "New state passed to containerStateChanged() should equal the " +
+            "container's current state"
+        );
+        Assert.equal(newState, container.state);
+
+        try {
+          switch (newState) {
+            case Ci.nsINavHistoryContainerResultNode.STATE_LOADING:
+              self.loading(container, newState, oldState);
+              break;
+            case Ci.nsINavHistoryContainerResultNode.STATE_OPENED:
+              self.opened(container, newState, oldState);
+              break;
+            case Ci.nsINavHistoryContainerResultNode.STATE_CLOSED:
+              self.closed(container, newState, oldState);
+              break;
+            default:
+              do_throw("Unexpected new state! " + newState);
+          }
+        } catch (err) {
+          do_throw(err);
+        }
+      },
+    };
+    this.result.addObserver(this.observer);
+
+    print("Opening container");
+    this.result.root.containerOpen = true;
+  },
+
+  /**
+   * Starts the test and returns a promise resolved when the test completes.
+   */
+  run() {
+    this.openContainer();
+    return this.deferNextTest.promise;
+  },
+
+  /**
+   * This must be called before run().  It adds a bookmark and sets up the
+   * test's result.  Override if need be.
+   */
+  async setup() {
+    // Populate the database with different types of bookmark items.
+    this.data = DataHelper.makeDataArray([
+      { type: "bookmark" },
+      { type: "separator" },
+      { type: "folder" },
+      { type: "bookmark", uri: "place:terms=foo" },
+    ]);
+    await task_populateDB(this.data);
+
+    // Make a query.
+    this.query = PlacesUtils.history.getNewQuery();
+    this.query.setParents([DataHelper.defaults.bookmark.parentGuid]);
+    this.opts = PlacesUtils.history.getNewQueryOptions();
+    this.opts.asyncEnabled = true;
+    this.result = PlacesUtils.history.executeQuery(this.query, this.opts);
+  },
+
+  /**
+   * Call this when the test has succeeded.  It cleans up resources and starts
+   * the next test.
+   */
+  success() {
+    this.result.removeObserver(this.observer);
+
+    // Resolve the promise object that indicates that the next test can be run.
+    this.deferNextTest.resolve();
+  },
+};
+
+/**
+ * This makes it a little bit easier to use the functions of head_queries.js.
+ */
+var DataHelper = {
+  defaults: {
+    bookmark: {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      uri: "http://example.com/",
+      title: "test bookmark",
+    },
+
+    folder: {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      title: "test folder",
+    },
+
+    separator: {
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+  },
+
+  /**
+   * Converts an array of simple bookmark item descriptions to the more verbose
+   * format required by task_populateDB() in head_queries.js.
+   *
+   * @param  aData
+   *         An array of objects, each of which describes a bookmark item.
+   * @return An array of objects suitable for passing to populateDB().
+   */
+  makeDataArray: function DH_makeDataArray(aData) {
+    let self = this;
+    return aData.map(function (dat) {
+      let type = dat.type;
+      dat = self._makeDataWithDefaults(dat, self.defaults[type]);
+      switch (type) {
+        case "bookmark":
+          return {
+            isBookmark: true,
+            uri: dat.uri,
+            parentGuid: dat.parentGuid,
+            index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+            title: dat.title,
+            isInQuery: true,
+          };
+        case "separator":
+          return {
+            isSeparator: true,
+            parentGuid: dat.parentGuid,
+            index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+            isInQuery: true,
+          };
+        case "folder":
+          return {
+            isFolder: true,
+            parentGuid: dat.parentGuid,
+            index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+            title: dat.title,
+            isInQuery: true,
+          };
+        default:
+          do_throw("Unknown data type when populating DB: " + type);
+          return undefined;
+      }
+    });
+  },
+
+  /**
+   * Returns a copy of aData, except that any properties that are undefined but
+   * defined in aDefaults are set to the corresponding values in aDefaults.
+   *
+   * @param  aData
+   *         An object describing a bookmark item.
+   * @param  aDefaults
+   *         An object describing the default bookmark item.
+   * @return A copy of aData with defaults values set.
+   */
+  _makeDataWithDefaults: function DH__makeDataWithDefaults(aData, aDefaults) {
+    let dat = {};
+    for (let [prop, val] of Object.entries(aDefaults)) {
+      dat[prop] = aData.hasOwnProperty(prop) ? aData[prop] : val;
+    }
+    return dat;
+  },
+};
+
+add_task(async function test_async() {
+  for (let test of tests) {
+    await PlacesUtils.bookmarks.eraseEverything();
+
+    Object.setPrototypeOf(test, new Test());
+    await test.setup();
+
+    print("------ Running test: " + test.desc);
+    await test.run();
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  print("All tests done, exiting");
+});
diff --git a/toolkit/components/places/tests/queries/test_bookmarks.js b/toolkit/components/places/tests/queries/test_bookmarks.js
new file mode 100644
index 0000000000..b5f2ef754f
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_bookmarks.js
@@ -0,0 +1,105 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_eraseEverything() {
+  info("Test folder with eraseEverything");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "remove-folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          { url: "http://mozilla.org/", title: "title 1" },
+          { url: "http://mozilla.org/", title: "title 2" },
+          { title: "sub-folder", type: PlacesUtils.bookmarks.TYPE_FOLDER },
+          { type: PlacesUtils.bookmarks.TYPE_SEPARATOR },
+        ],
+      },
+    ],
+  });
+
+  let unfiled = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  Assert.equal(unfiled.childCount, 1, "There should be 1 folder");
+  let folder = unfiled.getChild(0);
+  // Test dateAdded and lastModified properties.
+  Assert.equal(typeof folder.dateAdded, "number");
+  Assert.ok(folder.dateAdded > 0);
+  Assert.equal(typeof folder.lastModified, "number");
+  Assert.ok(folder.lastModified > 0);
+
+  let root = PlacesUtils.getFolderContents(folder.bookmarkGuid).root;
+  Assert.equal(root.childCount, 4, "The folder should have 4 children");
+  for (let i = 0; i < root.childCount; ++i) {
+    let node = root.getChild(i);
+    Assert.greater(node.itemId, 0, "The node should have an itemId");
+  }
+  Assert.equal(root.getChild(0).title, "title 1");
+  Assert.equal(root.getChild(1).title, "title 2");
+
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // Refetch the guid to refresh the data.
+  unfiled = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  Assert.equal(unfiled.childCount, 0);
+  unfiled.containerOpen = false;
+});
+
+add_task(async function test_search_title() {
+  let title = "ZZZXXXYYY";
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://mozilla.org/",
+    title,
+  });
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "ZZZXXXYYY";
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  let node = root.getChild(0);
+  Assert.equal(node.title, title);
+
+  // Test dateAdded and lastModified properties.
+  Assert.equal(typeof node.dateAdded, "number");
+  Assert.ok(node.dateAdded > 0);
+  Assert.equal(typeof node.lastModified, "number");
+  Assert.ok(node.lastModified > 0);
+  Assert.equal(node.bookmarkGuid, bm.guid);
+
+  await PlacesUtils.bookmarks.remove(bm);
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+});
+
+add_task(async function test_long_title() {
+  let title = Array(TITLE_LENGTH_MAX + 5).join("A");
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://mozilla.org/",
+    title,
+  });
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  let node = root.getChild(0);
+  Assert.equal(node.title, title.substr(0, TITLE_LENGTH_MAX));
+
+  // Update with another long title.
+  let newTitle = Array(TITLE_LENGTH_MAX + 5).join("B");
+  bm.title = newTitle;
+  await PlacesUtils.bookmarks.update(bm);
+  Assert.equal(node.title, newTitle.substr(0, TITLE_LENGTH_MAX));
+
+  await PlacesUtils.bookmarks.remove(bm);
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_containersQueries_sorting.js b/toolkit/components/places/tests/queries/test_containersQueries_sorting.js
new file mode 100644
index 0000000000..9cdc0f2a52
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_containersQueries_sorting.js
@@ -0,0 +1,492 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Testing behavior of bug 473157
+ * "Want to sort history in container view without sorting the containers"
+ * and regression bug 488783
+ * Tags list no longer sorted (alphabetized).
+ * This test is for global testing sorting containers queries.
+ */
+
+// Globals and Constants
+
+var resultTypes = [
+  {
+    value: Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY,
+    name: "RESULTS_AS_DATE_QUERY",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY,
+    name: "RESULTS_AS_SITE_QUERY",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY,
+    name: "RESULTS_AS_DATE_SITE_QUERY",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAGS_ROOT,
+    name: "RESULTS_AS_TAGS_ROOT",
+  },
+];
+
+var sortingModes = [
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING,
+    name: "SORT_BY_TITLE_ASCENDING",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING,
+    name: "SORT_BY_TITLE_DESCENDING",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING,
+    name: "SORT_BY_DATE_ASCENDING",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING,
+    name: "SORT_BY_DATE_DESCENDING",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_ASCENDING,
+    name: "SORT_BY_DATEADDED_ASCENDING",
+  },
+  {
+    value: Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_DESCENDING,
+    name: "SORT_BY_DATEADDED_DESCENDING",
+  },
+];
+
+// These pages will be added from newest to oldest and from less visited to most
+// visited.
+var pages = [
+  "http://www.mozilla.org/c/",
+  "http://www.mozilla.org/a/",
+  "http://www.mozilla.org/b/",
+  "http://www.mozilla.com/c/",
+  "http://www.mozilla.com/a/",
+  "http://www.mozilla.com/b/",
+];
+
+var tags = ["mozilla", "Development", "test"];
+
+// Test Runner
+
+/**
+ * Enumerates all the sequences of the cartesian product of the arrays contained
+ * in aSequences.  Examples:
+ *
+ *   cartProd([[1, 2, 3], ["a", "b"]], callback);
+ *   // callback is called 3 * 2 = 6 times with the following arrays:
+ *   // [1, "a"], [1, "b"], [2, "a"], [2, "b"], [3, "a"], [3, "b"]
+ *
+ *   cartProd([["a"], [1, 2, 3], ["X", "Y"]], callback);
+ *   // callback is called 1 * 3 * 2 = 6 times with the following arrays:
+ *   // ["a", 1, "X"], ["a", 1, "Y"], ["a", 2, "X"], ["a", 2, "Y"],
+ *   // ["a", 3, "X"], ["a", 3, "Y"]
+ *
+ *   cartProd([[1], [2], [3], [4]], callback);
+ *   // callback is called 1 * 1 * 1 * 1 = 1 time with the following array:
+ *   // [1, 2, 3, 4]
+ *
+ *   cartProd([], callback);
+ *   // callback is 0 times
+ *
+ *   cartProd([[1, 2, 3, 4]], callback);
+ *   // callback is called 4 times with the following arrays:
+ *   // [1], [2], [3], [4]
+ *
+ * @param  aSequences
+ *         an array that contains an arbitrary number of arrays
+ * @param  aCallback
+ *         a function that is passed each sequence of the product as it's
+ *         computed
+ * @return the total number of sequences in the product
+ */
+function cartProd(aSequences, aCallback) {
+  if (aSequences.length === 0) {
+    return 0;
+  }
+
+  // For each sequence in aSequences, we maintain a pointer (an array index,
+  // really) to the element we're currently enumerating in that sequence
+  var seqEltPtrs = aSequences.map(i => 0);
+
+  var numProds = 0;
+  var done = false;
+  while (!done) {
+    numProds++;
+
+    // prod = sequence in product we're currently enumerating
+    var prod = [];
+    for (var i = 0; i < aSequences.length; i++) {
+      prod.push(aSequences[i][seqEltPtrs[i]]);
+    }
+    aCallback(prod);
+
+    // The next sequence in the product differs from the current one by just a
+    // single element.  Determine which element that is.  We advance the
+    // "rightmost" element pointer to the "right" by one.  If we move past the
+    // end of that pointer's sequence, reset the pointer to the first element
+    // in its sequence and then try the sequence to the "left", and so on.
+
+    // seqPtr = index of rightmost input sequence whose element pointer is not
+    // past the end of the sequence
+    var seqPtr = aSequences.length - 1;
+    while (!done) {
+      // Advance the rightmost element pointer.
+      seqEltPtrs[seqPtr]++;
+
+      // The rightmost element pointer is past the end of its sequence.
+      if (seqEltPtrs[seqPtr] >= aSequences[seqPtr].length) {
+        seqEltPtrs[seqPtr] = 0;
+        seqPtr--;
+
+        // All element pointers are past the ends of their sequences.
+        if (seqPtr < 0) {
+          done = true;
+        }
+      } else {
+        break;
+      }
+    }
+  }
+  return numProds;
+}
+
+/**
+ * Test a query based on passed-in options.
+ *
+ * @param aSequence
+ *        array of options we will use to query.
+ */
+function test_query_callback(aSequence) {
+  Assert.equal(aSequence.length, 2);
+  var resultType = aSequence[0];
+  var sortingMode = aSequence[1];
+  print(
+    "\n\n*** Testing default sorting for resultType (" +
+      resultType.name +
+      ") and sortingMode (" +
+      sortingMode.name +
+      ")"
+  );
+
+  // Skip invalid combinations sorting queries by none.
+  if (
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAGS_ROOT &&
+    (sortingMode.value == Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING ||
+      sortingMode.value == Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING)
+  ) {
+    // This is a bookmark query, we can't sort by visit date.
+    sortingMode.value = Ci.nsINavHistoryQueryOptions.SORT_BY_NONE;
+  }
+  if (
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY ||
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  ) {
+    // This is an history query, we can't sort by date added.
+    if (
+      sortingMode.value ==
+        Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_ASCENDING ||
+      sortingMode.value ==
+        Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_DESCENDING
+    ) {
+      sortingMode.value = Ci.nsINavHistoryQueryOptions.SORT_BY_NONE;
+    }
+  }
+
+  // Create a new query with required options.
+  var query = PlacesUtils.history.getNewQuery();
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = resultType.value;
+  options.sortingMode = sortingMode.value;
+
+  // Compare resultset with expectedData.
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+
+  if (
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  ) {
+    // Date containers are always sorted by date descending.
+    check_children_sorting(
+      root,
+      Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING
+    );
+  } else {
+    check_children_sorting(root, sortingMode.value);
+  }
+
+  // Now Check sorting of the first child container.
+  var container = root
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  container.containerOpen = true;
+
+  if (
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  ) {
+    // Has more than one level of containers, first we check the sorting of
+    // the first level (site containers), those won't inherit sorting...
+    check_children_sorting(
+      container,
+      Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING
+    );
+    // ...then we check sorting of the contained urls, we can't inherit sorting
+    // since the above level does not inherit it, so they will be sorted by
+    // title ascending.
+    let innerContainer = container
+      .getChild(0)
+      .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    innerContainer.containerOpen = true;
+    check_children_sorting(
+      innerContainer,
+      Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING
+    );
+    innerContainer.containerOpen = false;
+  } else if (
+    resultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAGS_ROOT
+  ) {
+    // Sorting mode for tag contents is hardcoded for now, to allow for faster
+    // duplicates filtering.
+    check_children_sorting(
+      container,
+      Ci.nsINavHistoryQueryOptions.SORT_BY_NONE
+    );
+  } else {
+    check_children_sorting(container, sortingMode.value);
+  }
+
+  container.containerOpen = false;
+  root.containerOpen = false;
+
+  test_result_sortingMode_change(result, resultType, sortingMode);
+}
+
+/**
+ * Sets sortingMode on aResult and checks for correct sorting of children.
+ * Containers should not change their sorting, while contained uri nodes should.
+ *
+ * @param aResult
+ *        nsINavHistoryResult generated by our query.
+ * @param aResultType
+ *        required result type.
+ * @param aOriginalSortingMode
+ *        the sorting mode from query's options.
+ */
+function test_result_sortingMode_change(
+  aResult,
+  aResultType,
+  aOriginalSortingMode
+) {
+  var root = aResult.root;
+  // Now we set sortingMode on the result and check that containers are not
+  // sorted while children are.
+  sortingModes.forEach(function sortingModeChecker(aForcedSortingMode) {
+    print(
+      "\n* Test setting sortingMode (" +
+        aForcedSortingMode.name +
+        ") " +
+        "on result with resultType (" +
+        aResultType.name +
+        ") " +
+        "currently sorted as (" +
+        aOriginalSortingMode.name +
+        ")"
+    );
+
+    aResult.sortingMode = aForcedSortingMode.value;
+    root.containerOpen = true;
+
+    if (
+      aResultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+      aResultType.value ==
+        Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+    ) {
+      // Date containers are always sorted by date descending.
+      check_children_sorting(
+        root,
+        Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING
+      );
+    } else if (
+      aResultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY &&
+      (aOriginalSortingMode.value ==
+        Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING ||
+        aOriginalSortingMode.value ==
+          Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING)
+    ) {
+      // Site containers don't have a good time property to sort by.
+      check_children_sorting(root, Ci.nsINavHistoryQueryOptions.SORT_BY_NONE);
+    } else {
+      check_children_sorting(root, aOriginalSortingMode.value);
+    }
+
+    // Now Check sorting of the first child container.
+    var container = root
+      .getChild(0)
+      .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    container.containerOpen = true;
+
+    if (
+      aResultType.value ==
+      Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+    ) {
+      // Has more than one level of containers, first we check the sorting of
+      // the first level (site containers), those won't be sorted...
+      check_children_sorting(
+        container,
+        Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING
+      );
+      // ...then we check sorting of the second level of containers, result
+      // will sort them through recursiveSort.
+      let innerContainer = container
+        .getChild(0)
+        .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+      innerContainer.containerOpen = true;
+      check_children_sorting(innerContainer, aForcedSortingMode.value);
+      innerContainer.containerOpen = false;
+    } else {
+      if (
+        aResultType.value ==
+          Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY ||
+        aResultType.value ==
+          Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY ||
+        aResultType.value == Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY
+      ) {
+        // Date containers are always sorted by date descending.
+        check_children_sorting(root, Ci.nsINavHistoryQueryOptions.SORT_BY_NONE);
+      } else {
+        check_children_sorting(root, aOriginalSortingMode.value);
+      }
+
+      // Children should always be sorted.
+      check_children_sorting(container, aForcedSortingMode.value);
+    }
+
+    container.containerOpen = false;
+    root.containerOpen = false;
+  });
+}
+
+/**
+ * Test if children of aRootNode are correctly sorted.
+ * @param aRootNode
+ *        already opened root node from our query's result.
+ * @param aExpectedSortingMode
+ *        The sortingMode we expect results to be.
+ */
+function check_children_sorting(aRootNode, aExpectedSortingMode) {
+  var results = [];
+  print("Found children:");
+  for (let i = 0; i < aRootNode.childCount; i++) {
+    results[i] = aRootNode.getChild(i);
+    print(i + " " + results[i].title);
+  }
+
+  // Helper for case insensitive string comparison.
+  function caseInsensitiveStringComparator(a, b) {
+    var aLC = a.toLowerCase();
+    var bLC = b.toLowerCase();
+    if (aLC < bLC) {
+      return -1;
+    }
+    if (aLC > bLC) {
+      return 1;
+    }
+    return 0;
+  }
+
+  // Get a comparator based on expected sortingMode.
+  var comparator;
+  switch (aExpectedSortingMode) {
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_NONE:
+      comparator = function (a, b) {
+        return 0;
+      };
+      break;
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING:
+      comparator = function (a, b) {
+        return caseInsensitiveStringComparator(a.title, b.title);
+      };
+      break;
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING:
+      comparator = function (a, b) {
+        return -caseInsensitiveStringComparator(a.title, b.title);
+      };
+      break;
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING:
+      comparator = function (a, b) {
+        return a.time - b.time;
+      };
+      break;
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING:
+      comparator = function (a, b) {
+        return b.time - a.time;
+      };
+    // fall through - we shouldn't do this, see bug 1572437.
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_ASCENDING:
+      comparator = function (a, b) {
+        return a.dateAdded - b.dateAdded;
+      };
+      break;
+    case Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_DESCENDING:
+      comparator = function (a, b) {
+        return b.dateAdded - a.dateAdded;
+      };
+      break;
+    default:
+      do_throw("Unknown sorting type: " + aExpectedSortingMode);
+  }
+
+  // Make an independent copy of the results array and sort it.
+  var sortedResults = results.slice();
+  sortedResults.sort(comparator);
+  // Actually compare returned children with our sorted array.
+  for (let i = 0; i < sortedResults.length; i++) {
+    if (sortedResults[i].title != results[i].title) {
+      print(
+        i +
+          " index wrong, expected " +
+          sortedResults[i].title +
+          " found " +
+          results[i].title
+      );
+    }
+    Assert.equal(sortedResults[i].title, results[i].title);
+  }
+}
+
+// Main
+
+add_task(async function test_containersQueries_sorting() {
+  // Add visits, bookmarks and tags to our database.
+  var timeInMilliseconds = Date.now();
+  var visitCount = 0;
+  var dayOffset = 0;
+  var visits = [];
+  pages.forEach(aPageUrl =>
+    visits.push({
+      isVisit: true,
+      isBookmark: true,
+      transType: Ci.nsINavHistoryService.TRANSITION_TYPED,
+      uri: aPageUrl,
+      title: aPageUrl,
+      // subtract 5 hours per iteration, to expose more than one day container.
+      lastVisit: (timeInMilliseconds - 18000 * 1000 * dayOffset++) * 1000,
+      visitCount: visitCount++,
+      isTag: true,
+      tagArray: tags,
+      isInQuery: true,
+    })
+  );
+  await task_populateDB(visits);
+
+  cartProd([resultTypes, sortingModes], test_query_callback);
+});
diff --git a/toolkit/components/places/tests/queries/test_downloadHistory_liveUpdate.js b/toolkit/components/places/tests/queries/test_downloadHistory_liveUpdate.js
new file mode 100644
index 0000000000..ba0f528b62
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_downloadHistory_liveUpdate.js
@@ -0,0 +1,121 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures that download history (filtered by transition) queries
+// don't invalidate (and requery) too often.
+
+function accumulateNotifications(result) {
+  let notifications = [];
+  let resultObserver = new Proxy(NavHistoryResultObserver, {
+    get(target, name) {
+      if (name == "check") {
+        result.removeObserver(resultObserver, false);
+        return expectedNotifications =>
+          Assert.deepEqual(notifications, expectedNotifications);
+      }
+      // ignore a few uninteresting notifications.
+      if (["QueryInterface", "containerStateChanged"].includes(name)) {
+        return () => {};
+      }
+      return () => {
+        notifications.push(name);
+      };
+    },
+  });
+  result.addObserver(resultObserver, false);
+  return resultObserver;
+}
+
+add_task(async function test_downloadhistory_query_notifications() {
+  const MAX_RESULTS = 5;
+  let query = PlacesUtils.history.getNewQuery();
+  query.setTransitions([PlacesUtils.history.TRANSITIONS.DOWNLOAD]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING;
+  options.maxResults = MAX_RESULTS;
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let notifications = accumulateNotifications(result);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+  // Add more maxResults downloads in order.
+  let transitions = Object.values(PlacesUtils.history.TRANSITIONS);
+  for (let transition of transitions) {
+    let uri = "http://fx-search.com/" + transition;
+    await PlacesTestUtils.addVisits({
+      uri,
+      transition,
+      title: "test " + transition,
+    });
+    // For each visit also set apart:
+    //  - a bookmark
+    //  - an annotation
+    //  - an icon
+    await PlacesUtils.bookmarks.insert({
+      url: uri,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+    await PlacesUtils.history.update({
+      url: uri,
+      annotations: new Map([["test/anno", "testValue"]]),
+    });
+    await PlacesTestUtils.addFavicons(new Map([[uri, SMALLPNG_DATA_URI.spec]]));
+  }
+  // Remove all the visits one by one.
+  for (let transition of transitions) {
+    let uri = Services.io.newURI("http://fx-search.com/" + transition);
+    await PlacesUtils.history.remove(uri);
+  }
+  root.containerOpen = false;
+  // We pretty much don't want to see invalidateContainer here, because that
+  // means we requeried.
+  // We also don't want to see changes caused by filtered-out transition types.
+  notifications.check([
+    "nodeHistoryDetailsChanged",
+    "nodeInserted",
+    "nodeTitleChanged",
+    "nodeIconChanged",
+    "nodeRemoved",
+  ]);
+});
+
+add_task(async function test_downloadhistory_query_filtering() {
+  const MAX_RESULTS = 3;
+  let query = PlacesUtils.history.getNewQuery();
+  query.setTransitions([PlacesUtils.history.TRANSITIONS.DOWNLOAD]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING;
+  options.maxResults = MAX_RESULTS;
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 0, "No visits found");
+  // Add more than maxResults downloads.
+  let uris = [];
+  // Define a monotonic visit date to ensure results order stability.
+  let visitDate = Date.now() * 1000;
+  for (let i = 0; i < MAX_RESULTS + 1; ++i, visitDate += 1000) {
+    let uri = `http://fx-search.com/download/${i}`;
+    await PlacesTestUtils.addVisits({
+      uri,
+      transition: PlacesUtils.history.TRANSITIONS.DOWNLOAD,
+      visitDate,
+    });
+    uris.push(uri);
+  }
+  // Add an older download visit out of the maxResults timeframe.
+  await PlacesTestUtils.addVisits({
+    uri: `http://fx-search.com/download/unordered`,
+    transition: PlacesUtils.history.TRANSITIONS.DOWNLOAD,
+    visitDate: new Date(Date.now() - 7200000),
+  });
+
+  Assert.equal(root.childCount, MAX_RESULTS, "Result should be limited");
+  // Invert the uris array because we are sorted by date descending.
+  uris.reverse();
+  for (let i = 0; i < root.childCount; ++i) {
+    let node = root.getChild(i);
+    Assert.equal(node.uri, uris[i], "Found the expected uri");
+  }
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_excludeQueries.js b/toolkit/components/places/tests/queries/test_excludeQueries.js
new file mode 100644
index 0000000000..c48f84c7f4
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_excludeQueries.js
@@ -0,0 +1,118 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+var bm;
+var fakeQuery;
+var folderShortcut;
+
+add_task(async function setup() {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://example.com/",
+    title: "a bookmark",
+  });
+  fakeQuery = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "place:terms=foo",
+    title: "a bookmark",
+  });
+  folderShortcut = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: `place:parent=${PlacesUtils.bookmarks.toolbarGuid}`,
+    title: "a bookmark",
+  });
+
+  checkBookmarkObject(bm);
+  checkBookmarkObject(fakeQuery);
+  checkBookmarkObject(folderShortcut);
+});
+
+add_task(async function test_bookmarks_url_query_implicit_exclusions() {
+  // When we run bookmarks url queries, we implicity filter out queries and
+  // folder shortcuts regardless of excludeQueries. They don't make sense to
+  // include in the results.
+  let expectedGuids = [bm.guid];
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.excludeQueries = true;
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(
+    root.childCount,
+    expectedGuids.length,
+    "Checking root child count"
+  );
+  for (let i = 0; i < expectedGuids.length; i++) {
+    Assert.equal(
+      root.getChild(i).bookmarkGuid,
+      expectedGuids[i],
+      "should have got the expected item"
+    );
+  }
+
+  root.containerOpen = false;
+});
+
+add_task(async function test_bookmarks_excludeQueries() {
+  // When excluding queries, we exclude actual queries, but not folder shortcuts.
+  let expectedGuids = [bm.guid, folderShortcut.guid];
+  let query = {},
+    options = {};
+  let queryString = `place:parent=${PlacesUtils.bookmarks.unfiledGuid}&excludeQueries=1`;
+  PlacesUtils.history.queryStringToQuery(queryString, query, options);
+
+  let root = PlacesUtils.history.executeQuery(query.value, options.value).root;
+  root.containerOpen = true;
+
+  Assert.equal(
+    root.childCount,
+    expectedGuids.length,
+    "Checking root child count"
+  );
+  for (let i = 0; i < expectedGuids.length; i++) {
+    Assert.equal(
+      root.getChild(i).bookmarkGuid,
+      expectedGuids[i],
+      "should have got the expected item"
+    );
+  }
+
+  root.containerOpen = false;
+});
+
+add_task(async function test_search_excludesQueries() {
+  // Searching implicity removes queries and folder shortcuts even if excludeQueries
+  // is not specified.
+  let expectedGuids = [bm.guid];
+
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "bookmark";
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(
+    root.childCount,
+    expectedGuids.length,
+    "Checking root child count"
+  );
+  for (let i = 0; i < expectedGuids.length; i++) {
+    Assert.equal(
+      root.getChild(i).bookmarkGuid,
+      expectedGuids[i],
+      "should have got the expected item"
+    );
+  }
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_history_queries_tags_liveUpdate.js b/toolkit/components/places/tests/queries/test_history_queries_tags_liveUpdate.js
new file mode 100644
index 0000000000..aef45ff8f1
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_history_queries_tags_liveUpdate.js
@@ -0,0 +1,131 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures that tags changes are correctly live-updated in a history
+// query.
+
+let timeInMicroseconds = PlacesUtils.toPRTime(Date.now() - 10000);
+
+function newTimeInMicroseconds() {
+  timeInMicroseconds = timeInMicroseconds + 1000;
+  return timeInMicroseconds;
+}
+
+var gTestData = [
+  {
+    isVisit: true,
+    uri: "http://example.com/1/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    isBookmark: true,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    title: "example1",
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/2/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    isBookmark: true,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    title: "example2",
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/3/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    isBookmark: true,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    title: "example3",
+  },
+];
+
+function newQueryWithOptions() {
+  return [
+    PlacesUtils.history.getNewQuery(),
+    PlacesUtils.history.getNewQueryOptions(),
+  ];
+}
+
+function testQueryContents(aQuery, aOptions, aCallback) {
+  let root = PlacesUtils.history.executeQuery(aQuery, aOptions).root;
+  root.containerOpen = true;
+  aCallback(root);
+  root.containerOpen = false;
+}
+
+add_task(async function test_initialize() {
+  await task_populateDB(gTestData);
+});
+
+add_task(function pages_query() {
+  let [query, options] = newQueryWithOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  testQueryContents(query, options, function (root) {
+    compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+    for (let i = 0; i < root.childCount; i++) {
+      let node = root.getChild(i);
+      let uri = NetUtil.newURI(node.uri);
+      Assert.equal(node.tags, null);
+      PlacesUtils.tagging.tagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, "test-tag");
+      PlacesUtils.tagging.untagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, null);
+    }
+  });
+});
+
+add_task(function visits_query() {
+  let [query, options] = newQueryWithOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  options.resultType = Ci.nsINavHistoryQueryOptions.RESULTS_AS_VISIT;
+  testQueryContents(query, options, function (root) {
+    compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+    for (let i = 0; i < root.childCount; i++) {
+      let node = root.getChild(i);
+      let uri = NetUtil.newURI(node.uri);
+      Assert.equal(node.tags, null);
+      PlacesUtils.tagging.tagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, "test-tag");
+      PlacesUtils.tagging.untagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, null);
+    }
+  });
+});
+
+add_task(function bookmark_parent_query() {
+  let [query, options] = newQueryWithOptions();
+  query.setParents([PlacesUtils.bookmarks.unfiledGuid]);
+  testQueryContents(query, options, function (root) {
+    compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+    for (let i = 0; i < root.childCount; i++) {
+      let node = root.getChild(i);
+      let uri = NetUtil.newURI(node.uri);
+      Assert.equal(node.tags, null);
+      PlacesUtils.tagging.tagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, "test-tag");
+      PlacesUtils.tagging.untagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, null);
+    }
+  });
+});
+
+add_task(function history_query() {
+  let [query, options] = newQueryWithOptions();
+  testQueryContents(query, options, function (root) {
+    compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+    for (let i = 0; i < root.childCount; i++) {
+      let node = root.getChild(i);
+      let uri = NetUtil.newURI(node.uri);
+      Assert.equal(node.tags, null);
+      PlacesUtils.tagging.tagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, null);
+      PlacesUtils.tagging.untagURI(uri, ["test-tag"]);
+      Assert.equal(node.tags, null);
+    }
+  });
+});
diff --git a/toolkit/components/places/tests/queries/test_history_queries_titles_liveUpdate.js b/toolkit/components/places/tests/queries/test_history_queries_titles_liveUpdate.js
new file mode 100644
index 0000000000..ac3931892f
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_history_queries_titles_liveUpdate.js
@@ -0,0 +1,217 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures that tags changes are correctly live-updated in a history
+// query.
+
+let timeInMicroseconds = PlacesUtils.toPRTime(Date.now() - 10000);
+
+function newTimeInMicroseconds() {
+  timeInMicroseconds = timeInMicroseconds + 1000;
+  return timeInMicroseconds;
+}
+
+var gTestData = [
+  {
+    isVisit: true,
+    uri: "http://example.com/1/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    title: "title1",
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/2/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    title: "title2",
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/3/",
+    lastVisit: newTimeInMicroseconds(),
+    isInQuery: true,
+    title: "title3",
+  },
+];
+
+function searchNodeHavingUrl(aRoot, aUrl) {
+  for (let i = 0; i < aRoot.childCount; i++) {
+    if (aRoot.getChild(i).uri == aUrl) {
+      return aRoot.getChild(i);
+    }
+  }
+  return undefined;
+}
+
+function newQueryWithOptions() {
+  return [
+    PlacesUtils.history.getNewQuery(),
+    PlacesUtils.history.getNewQueryOptions(),
+  ];
+}
+
+add_task(async function pages_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+  for (let i = 0; i < root.childCount; i++) {
+    let node = root.getChild(i);
+    Assert.equal(node.title, gTestData[i].title);
+    let uri = NetUtil.newURI(node.uri);
+    await PlacesTestUtils.addVisits({ uri, title: "changedTitle" });
+    Assert.equal(node.title, "changedTitle");
+    await PlacesTestUtils.addVisits({ uri, title: gTestData[i].title });
+    Assert.equal(node.title, gTestData[i].title);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function visits_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  options.resultType = Ci.nsINavHistoryQueryOptions.RESULTS_AS_VISIT;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+
+  for (let testData of gTestData) {
+    let uri = NetUtil.newURI(testData.uri);
+    let node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, testData.title);
+    await PlacesTestUtils.addVisits({ uri, title: "changedTitle" });
+    node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, "changedTitle");
+    await PlacesTestUtils.addVisits({ uri, title: testData.title });
+    node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, testData.title);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function pages_searchterm_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  query.searchTerms = "example";
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+  for (let i = 0; i < root.childCount; i++) {
+    let node = root.getChild(i);
+    let uri = NetUtil.newURI(node.uri);
+    Assert.equal(node.title, gTestData[i].title);
+    await PlacesTestUtils.addVisits({ uri, title: "changedTitle" });
+    Assert.equal(node.title, "changedTitle");
+    await PlacesTestUtils.addVisits({ uri, title: gTestData[i].title });
+    Assert.equal(node.title, gTestData[i].title);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function visits_searchterm_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  query.searchTerms = "example";
+  options.resultType = Ci.nsINavHistoryQueryOptions.RESULTS_AS_VISIT;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  compareArrayToResult([gTestData[0], gTestData[1], gTestData[2]], root);
+  for (let testData of gTestData) {
+    let uri = NetUtil.newURI(testData.uri);
+    let node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, testData.title);
+    await PlacesTestUtils.addVisits({ uri, title: "changedTitle" });
+    node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, "changedTitle");
+    await PlacesTestUtils.addVisits({ uri, title: testData.title });
+    node = searchNodeHavingUrl(root, testData.uri);
+    Assert.equal(node.title, testData.title);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function pages_searchterm_is_title_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  query.searchTerms = "match";
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  compareArrayToResult([], root);
+  for (let data of gTestData) {
+    let uri = NetUtil.newURI(data.uri);
+    let origTitle = data.title;
+    data.title = "match";
+    await PlacesTestUtils.addVisits({
+      uri,
+      title: data.title,
+      visitDate: data.lastVisit,
+    });
+    compareArrayToResult([data], root);
+    data.title = origTitle;
+    await PlacesTestUtils.addVisits({
+      uri,
+      title: data.title,
+      visitDate: data.lastVisit,
+    });
+    compareArrayToResult([], root);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function visits_searchterm_is_title_query() {
+  await task_populateDB(gTestData);
+
+  let [query, options] = newQueryWithOptions();
+  query.searchTerms = "match";
+  options.resultType = Ci.nsINavHistoryQueryOptions.RESULTS_AS_VISIT;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  compareArrayToResult([], root);
+  for (let data of gTestData) {
+    let uri = NetUtil.newURI(data.uri);
+    let origTitle = data.title;
+    data.title = "match";
+
+    info("Adding " + uri.spec);
+    await PlacesTestUtils.addVisits({
+      uri,
+      title: data.title,
+      visitDate: data.lastVisit,
+    });
+
+    compareArrayToResult([data], root);
+    data.title = origTitle;
+    info("Clobbering " + uri.spec);
+    await PlacesTestUtils.addVisits({
+      uri,
+      title: data.title,
+      visitDate: data.lastVisit,
+    });
+
+    compareArrayToResult([], root);
+  }
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/queries/test_options_inherit.js b/toolkit/components/places/tests/queries/test_options_inherit.js
new file mode 100644
index 0000000000..ae43350eda
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_options_inherit.js
@@ -0,0 +1,118 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests inheritance of certain query options like:
+ * excludeItems, excludeQueries, expandQueries.
+ */
+
+"use strict";
+
+add_task(async function () {
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "query",
+            url:
+              "place:queryType=" +
+              Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS,
+          },
+          { title: "bm", url: "http://example.com" },
+          {
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          },
+        ],
+      },
+      { title: "bm", url: "http://example.com" },
+      {
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      },
+    ],
+  });
+
+  await test_query({}, 3, 3, 2);
+  await test_query({ expandQueries: false }, 3, 3, 0);
+  await test_query({ excludeItems: true }, 1, 1, 0);
+  await test_query({ excludeItems: true, expandQueries: false }, 1, 1, 0);
+  await test_query({ excludeItems: true, excludeQueries: true }, 1, 0, 0);
+});
+
+async function test_query(
+  opts,
+  expectedRootCc,
+  expectedFolderCc,
+  expectedQueryCc
+) {
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.unfiledGuid]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  for (const [o, v] of Object.entries(opts)) {
+    info(`Setting ${o} to ${v}`);
+    options[o] = v;
+  }
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(root.childCount, expectedRootCc, "Checking root child count");
+  if (root.childCount > 0) {
+    let folder = root.getChild(0);
+    Assert.equal(folder.title, "folder", "Found the expected folder");
+
+    // Check the folder uri doesn't reflect the root options, since those
+    // options are inherited and not part of this node declaration.
+    checkURIOptions(folder.uri);
+
+    PlacesUtils.asContainer(folder).containerOpen = true;
+    Assert.equal(
+      folder.childCount,
+      expectedFolderCc,
+      "Checking folder child count"
+    );
+    if (folder.childCount) {
+      let placeQuery = folder.getChild(0);
+      PlacesUtils.asQuery(placeQuery).containerOpen = true;
+      Assert.equal(
+        placeQuery.childCount,
+        expectedQueryCc,
+        "Checking query child count"
+      );
+      placeQuery.containerOpen = false;
+    }
+    folder.containerOpen = false;
+  }
+  let f = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  checkURIOptions(root.getChild(root.childCount - 1).uri);
+  await PlacesUtils.bookmarks.remove(f);
+
+  root.containerOpen = false;
+}
+
+function checkURIOptions(uri) {
+  info("Checking options for uri " + uri);
+  let folderOptions = {};
+  PlacesUtils.history.queryStringToQuery(uri, {}, folderOptions);
+  folderOptions = folderOptions.value;
+  Assert.equal(
+    folderOptions.excludeItems,
+    false,
+    "ExcludeItems should not be changed"
+  );
+  Assert.equal(
+    folderOptions.excludeQueries,
+    false,
+    "ExcludeQueries should not be changed"
+  );
+  Assert.equal(
+    folderOptions.expandQueries,
+    true,
+    "ExpandQueries should not be changed"
+  );
+}
diff --git a/toolkit/components/places/tests/queries/test_queryMultipleFolder.js b/toolkit/components/places/tests/queries/test_queryMultipleFolder.js
new file mode 100644
index 0000000000..7c24bef74e
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_queryMultipleFolder.js
@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+var folderGuids = [];
+var bookmarkGuids = [];
+
+add_task(async function setup() {
+  // adding bookmarks in the folders
+  for (let i = 0; i < 3; ++i) {
+    let folder = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      title: `Folder${i}`,
+    });
+    folderGuids.push(folder.guid);
+
+    for (let j = 0; j < 7; ++j) {
+      let bm = await PlacesUtils.bookmarks.insert({
+        parentGuid: folderGuids[i],
+        url: `http://Bookmark${i}_${j}.com`,
+        title: "",
+      });
+      bookmarkGuids.push(bm.guid);
+    }
+  }
+});
+
+add_task(async function test_queryMultipleFolders_ids() {
+  // using queryStringToQuery
+  let query = {},
+    options = {};
+  let maxResults = 20;
+  let queryString = `place:${folderGuids
+    .map(guid => "parent=" + guid)
+    .join("&")}&sort=5&maxResults=${maxResults}`;
+  PlacesUtils.history.queryStringToQuery(queryString, query, options);
+  let rootNode = PlacesUtils.history.executeQuery(
+    query.value,
+    options.value
+  ).root;
+  rootNode.containerOpen = true;
+  let resultLength = rootNode.childCount;
+  Assert.equal(resultLength, maxResults);
+  for (let i = 0; i < resultLength; ++i) {
+    let node = rootNode.getChild(i);
+    Assert.equal(bookmarkGuids[i], node.bookmarkGuid, node.uri);
+  }
+  rootNode.containerOpen = false;
+
+  // using getNewQuery and getNewQueryOptions
+  query = PlacesUtils.history.getNewQuery();
+  options = PlacesUtils.history.getNewQueryOptions();
+  query.setParents(folderGuids);
+  options.sortingMode = options.SORT_BY_URI_ASCENDING;
+  options.maxResults = maxResults;
+  rootNode = PlacesUtils.history.executeQuery(query, options).root;
+  rootNode.containerOpen = true;
+  resultLength = rootNode.childCount;
+  Assert.equal(resultLength, maxResults);
+  for (let i = 0; i < resultLength; ++i) {
+    let node = rootNode.getChild(i);
+    Assert.equal(bookmarkGuids[i], node.bookmarkGuid, node.uri);
+  }
+  rootNode.containerOpen = false;
+});
+
+add_task(async function test_queryMultipleFolders_guids() {
+  // using queryStringToQuery
+  let query = {},
+    options = {};
+  let maxResults = 20;
+  let queryString = `place:${folderGuids
+    .map(guid => "parent=" + guid)
+    .join("&")}&sort=5&maxResults=${maxResults}`;
+  PlacesUtils.history.queryStringToQuery(queryString, query, options);
+  let rootNode = PlacesUtils.history.executeQuery(
+    query.value,
+    options.value
+  ).root;
+  rootNode.containerOpen = true;
+  let resultLength = rootNode.childCount;
+  Assert.equal(resultLength, maxResults);
+  for (let i = 0; i < resultLength; ++i) {
+    let node = rootNode.getChild(i);
+    Assert.equal(bookmarkGuids[i], node.bookmarkGuid, node.uri);
+  }
+  rootNode.containerOpen = false;
+
+  // using getNewQuery and getNewQueryOptions
+  query = PlacesUtils.history.getNewQuery();
+  options = PlacesUtils.history.getNewQueryOptions();
+  query.setParents(folderGuids);
+  options.sortingMode = options.SORT_BY_URI_ASCENDING;
+  options.maxResults = maxResults;
+  rootNode = PlacesUtils.history.executeQuery(query, options).root;
+  rootNode.containerOpen = true;
+  resultLength = rootNode.childCount;
+  Assert.equal(resultLength, maxResults);
+  for (let i = 0; i < resultLength; ++i) {
+    let node = rootNode.getChild(i);
+    Assert.equal(bookmarkGuids[i], node.bookmarkGuid, node.uri);
+  }
+  rootNode.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_querySerialization.js b/toolkit/components/places/tests/queries/test_querySerialization.js
new file mode 100644
index 0000000000..4c33854718
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_querySerialization.js
@@ -0,0 +1,718 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Tests Places query serialization.  Associated bug is
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=370197
+ *
+ * The simple idea behind this test is to try out different combinations of
+ * query switches and ensure that queries are the same before serialization
+ * as they are after de-serialization.
+ *
+ * In the code below, "switch" refers to a query option -- "option" in a broad
+ * sense, not nsINavHistoryQueryOptions specifically (which is why we refer to
+ * them as switches, not options).  Both nsINavHistoryQuery and
+ * nsINavHistoryQueryOptions allow you to specify switches that affect query
+ * strings.  nsINavHistoryQuery instances have attributes hasBeginTime,
+ * hasEndTime, hasSearchTerms, and so on.  nsINavHistoryQueryOptions instances
+ * have attributes sortingMode, resultType, excludeItems, etc.
+ *
+ * Ideally we would like to test all 2^N subsets of switches, where N is the
+ * total number of switches; switches might interact in erroneous or other ways
+ * we do not expect.  However, since N is large (21 at this time), that's
+ * impractical for a single test in a suite.
+ *
+ * Instead we choose all possible subsets of a certain, smaller size.  In fact
+ * we begin by choosing CHOOSE_HOW_MANY_SWITCHES_LO and ramp up to
+ * CHOOSE_HOW_MANY_SWITCHES_HI.
+ *
+ * There are two more wrinkles.  First, for some switches we'd like to be able to
+ * test multiple values.  For example, it seems like a good idea to test both an
+ * empty string and a non-empty string for switch nsINavHistoryQuery.searchTerms.
+ * When switches have more than one value for a test run, we use the Cartesian
+ * product of their values to generate all possible combinations of values.
+ *
+ * To summarize, here's how this test works:
+ *
+ * - For n = CHOOSE_HOW_MANY_SWITCHES_LO to CHOOSE_HOW_MANY_SWITCHES_HI:
+ *   - From the total set of switches choose all possible subsets of size n.
+ *     For each of those subsets s:
+ *     - Collect the test runs of each switch in subset s and take their
+ *       Cartesian product.  For each sequence in the product:
+ *       - Create nsINavHistoryQuery and nsINavHistoryQueryOptions objects
+ *         with the chosen switches and test run values.
+ *       - Serialize the query.
+ *       - De-serialize and ensure that the de-serialized query objects equal
+ *         the originals.
+ */
+
+const CHOOSE_HOW_MANY_SWITCHES_LO = 1;
+const CHOOSE_HOW_MANY_SWITCHES_HI = 2;
+
+// The switches are represented by objects below, in arrays querySwitches and
+// queryOptionSwitches.  Use them to set up test runs.
+//
+// Some switches have special properties (where noted), but all switches must
+// have the following properties:
+//
+//   matches: A function that takes two nsINavHistoryQuery objects (in the case
+//            of nsINavHistoryQuery switches) or two nsINavHistoryQueryOptions
+//            objects (for nsINavHistoryQueryOptions switches) and returns true
+//            if the values of the switch in the two objects are equal.  This is
+//            the foundation of how we determine if two queries are equal.
+//   runs:    An array of functions.  Each function takes an nsINavHistoryQuery
+//            object and an nsINavHistoryQueryOptions object.  The functions
+//            should set the attributes of one of the two objects as appropriate
+//            to their switches.  This is how switch values are set for each test
+//            run.
+//
+// The following properties are optional:
+//
+//   desc:    An informational string to print out during runs when the switch
+//            is chosen.  Hopefully helpful if the test fails.
+
+// nsINavHistoryQuery switches
+const querySwitches = [
+  // hasBeginTime
+  {
+    // flag and subswitches are used by the flagSwitchMatches function.  Several
+    // of the nsINavHistoryQuery switches (like this one) are really guard flags
+    // that indicate if other "subswitches" are enabled.
+    flag: "hasBeginTime",
+    subswitches: ["beginTime", "beginTimeReference", "absoluteBeginTime"],
+    desc: "nsINavHistoryQuery.hasBeginTime",
+    matches: flagSwitchMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.beginTime = Date.now() * 1000;
+        aQuery.beginTimeReference = Ci.nsINavHistoryQuery.TIME_RELATIVE_EPOCH;
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.beginTime = Date.now() * 1000;
+        aQuery.beginTimeReference = Ci.nsINavHistoryQuery.TIME_RELATIVE_TODAY;
+      },
+    ],
+  },
+  // hasEndTime
+  {
+    flag: "hasEndTime",
+    subswitches: ["endTime", "endTimeReference", "absoluteEndTime"],
+    desc: "nsINavHistoryQuery.hasEndTime",
+    matches: flagSwitchMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.endTime = Date.now() * 1000;
+        aQuery.endTimeReference = Ci.nsINavHistoryQuery.TIME_RELATIVE_EPOCH;
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.endTime = Date.now() * 1000;
+        aQuery.endTimeReference = Ci.nsINavHistoryQuery.TIME_RELATIVE_TODAY;
+      },
+    ],
+  },
+  // hasSearchTerms
+  {
+    flag: "hasSearchTerms",
+    subswitches: ["searchTerms"],
+    desc: "nsINavHistoryQuery.hasSearchTerms",
+    matches: flagSwitchMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.searchTerms = "shrimp and white wine";
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.searchTerms = "";
+      },
+    ],
+  },
+  // hasDomain
+  {
+    flag: "hasDomain",
+    subswitches: ["domain", "domainIsHost"],
+    desc: "nsINavHistoryQuery.hasDomain",
+    matches: flagSwitchMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.domain = "mozilla.com";
+        aQuery.domainIsHost = false;
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.domain = "www.mozilla.com";
+        aQuery.domainIsHost = true;
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.domain = "";
+      },
+    ],
+  },
+  // hasUri
+  {
+    flag: "hasUri",
+    subswitches: ["uri"],
+    desc: "nsINavHistoryQuery.hasUri",
+    matches: flagSwitchMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.uri = uri("http://mozilla.com");
+      },
+    ],
+  },
+  // minVisits
+  {
+    // property is used by function simplePropertyMatches.
+    property: "minVisits",
+    desc: "nsINavHistoryQuery.minVisits",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.minVisits = 0x7fffffff; // 2^31 - 1
+      },
+    ],
+  },
+  // maxVisits
+  {
+    property: "maxVisits",
+    desc: "nsINavHistoryQuery.maxVisits",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.maxVisits = 0x7fffffff; // 2^31 - 1
+      },
+    ],
+  },
+  // getFolders
+  {
+    desc: "nsINavHistoryQuery.getParents",
+    matches(aQuery1, aQuery2) {
+      var q1Parents = aQuery1.getParents();
+      var q2Parents = aQuery2.getParents();
+      if (q1Parents.length !== q2Parents.length) {
+        return false;
+      }
+      for (let i = 0; i < q1Parents.length; i++) {
+        if (!q2Parents.includes(q1Parents[i])) {
+          return false;
+        }
+      }
+      for (let i = 0; i < q2Parents.length; i++) {
+        if (!q1Parents.includes(q2Parents[i])) {
+          return false;
+        }
+      }
+      return true;
+    },
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.setParents([]);
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.setParents([PlacesUtils.bookmarks.rootGuid]);
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.setParents([
+          PlacesUtils.bookmarks.rootGuid,
+          PlacesUtils.bookmarks.tagsGuid,
+        ]);
+      },
+    ],
+  },
+  // tags
+  {
+    desc: "nsINavHistoryQuery.getTags",
+    matches(aQuery1, aQuery2) {
+      if (aQuery1.tagsAreNot !== aQuery2.tagsAreNot) {
+        return false;
+      }
+      var q1Tags = aQuery1.tags;
+      var q2Tags = aQuery2.tags;
+      if (q1Tags.length !== q2Tags.length) {
+        return false;
+      }
+      for (let i = 0; i < q1Tags.length; i++) {
+        if (!q2Tags.includes(q1Tags[i])) {
+          return false;
+        }
+      }
+      for (let i = 0; i < q2Tags.length; i++) {
+        if (!q1Tags.includes(q2Tags[i])) {
+          return false;
+        }
+      }
+      return true;
+    },
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.tags = [];
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.tags = [""];
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.tags = [
+          "foo",
+          "七難",
+          "",
+          "いっぱいおっぱい",
+          "Abracadabra",
+          "１２３",
+          "Here's a pretty long tag name with some = signs and 1 2 3s and spaces oh jeez will it work I hope so!",
+          "アスキーでございません",
+          "あいうえお",
+        ];
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.tags = [
+          "foo",
+          "七難",
+          "",
+          "いっぱいおっぱい",
+          "Abracadabra",
+          "１２３",
+          "Here's a pretty long tag name with some = signs and 1 2 3s and spaces oh jeez will it work I hope so!",
+          "アスキーでございません",
+          "あいうえお",
+        ];
+        aQuery.tagsAreNot = true;
+      },
+    ],
+  },
+  // transitions
+  {
+    desc: "tests nsINavHistoryQuery.getTransitions",
+    matches(aQuery1, aQuery2) {
+      var q1Trans = aQuery1.getTransitions();
+      var q2Trans = aQuery2.getTransitions();
+      if (q1Trans.length !== q2Trans.length) {
+        return false;
+      }
+      for (let i = 0; i < q1Trans.length; i++) {
+        if (!q2Trans.includes(q1Trans[i])) {
+          return false;
+        }
+      }
+      for (let i = 0; i < q2Trans.length; i++) {
+        if (!q1Trans.includes(q2Trans[i])) {
+          return false;
+        }
+      }
+      return true;
+    },
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQuery.setTransitions([]);
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.setTransitions([Ci.nsINavHistoryService.TRANSITION_DOWNLOAD]);
+      },
+      function (aQuery, aQueryOptions) {
+        aQuery.setTransitions([
+          Ci.nsINavHistoryService.TRANSITION_TYPED,
+          Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+        ]);
+      },
+    ],
+  },
+];
+
+// nsINavHistoryQueryOptions switches
+const queryOptionSwitches = [
+  // sortingMode
+  {
+    desc: "nsINavHistoryQueryOptions.sortingMode",
+    matches(aOptions1, aOptions2) {
+      if (aOptions1.sortingMode === aOptions2.sortingMode) {
+        return true;
+      }
+      return false;
+    },
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.sortingMode = aQueryOptions.SORT_BY_DATE_ASCENDING;
+      },
+    ],
+  },
+  // resultType
+  {
+    // property is used by function simplePropertyMatches.
+    property: "resultType",
+    desc: "nsINavHistoryQueryOptions.resultType",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.resultType = aQueryOptions.RESULTS_AS_URI;
+      },
+    ],
+  },
+  // excludeItems
+  {
+    property: "excludeItems",
+    desc: "nsINavHistoryQueryOptions.excludeItems",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.excludeItems = true;
+      },
+    ],
+  },
+  // excludeQueries
+  {
+    property: "excludeQueries",
+    desc: "nsINavHistoryQueryOptions.excludeQueries",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.excludeQueries = true;
+      },
+    ],
+  },
+  // expandQueries
+  {
+    property: "expandQueries",
+    desc: "nsINavHistoryQueryOptions.expandQueries",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.expandQueries = true;
+      },
+    ],
+  },
+  // includeHidden
+  {
+    property: "includeHidden",
+    desc: "nsINavHistoryQueryOptions.includeHidden",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.includeHidden = true;
+      },
+    ],
+  },
+  // maxResults
+  {
+    property: "maxResults",
+    desc: "nsINavHistoryQueryOptions.maxResults",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.maxResults = 0xffffffff; // 2^32 - 1
+      },
+    ],
+  },
+  // queryType
+  {
+    property: "queryType",
+    desc: "nsINavHistoryQueryOptions.queryType",
+    matches: simplePropertyMatches,
+    runs: [
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.queryType = aQueryOptions.QUERY_TYPE_HISTORY;
+      },
+      function (aQuery, aQueryOptions) {
+        aQueryOptions.queryType = aQueryOptions.QUERY_TYPE_BOOKMARKS;
+      },
+    ],
+  },
+];
+
+/**
+ * Enumerates all the sequences of the cartesian product of the arrays contained
+ * in aSequences.  Examples:
+ *
+ *   cartProd([[1, 2, 3], ["a", "b"]], callback);
+ *   // callback is called 3 * 2 = 6 times with the following arrays:
+ *   // [1, "a"], [1, "b"], [2, "a"], [2, "b"], [3, "a"], [3, "b"]
+ *
+ *   cartProd([["a"], [1, 2, 3], ["X", "Y"]], callback);
+ *   // callback is called 1 * 3 * 2 = 6 times with the following arrays:
+ *   // ["a", 1, "X"], ["a", 1, "Y"], ["a", 2, "X"], ["a", 2, "Y"],
+ *   // ["a", 3, "X"], ["a", 3, "Y"]
+ *
+ *   cartProd([[1], [2], [3], [4]], callback);
+ *   // callback is called 1 * 1 * 1 * 1 = 1 time with the following array:
+ *   // [1, 2, 3, 4]
+ *
+ *   cartProd([], callback);
+ *   // callback is 0 times
+ *
+ *   cartProd([[1, 2, 3, 4]], callback);
+ *   // callback is called 4 times with the following arrays:
+ *   // [1], [2], [3], [4]
+ *
+ * @param  aSequences
+ *         an array that contains an arbitrary number of arrays
+ * @param  aCallback
+ *         a function that is passed each sequence of the product as it's
+ *         computed
+ * @return the total number of sequences in the product
+ */
+function cartProd(aSequences, aCallback) {
+  if (aSequences.length === 0) {
+    return 0;
+  }
+
+  // For each sequence in aSequences, we maintain a pointer (an array index,
+  // really) to the element we're currently enumerating in that sequence
+  var seqEltPtrs = aSequences.map(i => 0);
+
+  var numProds = 0;
+  var done = false;
+  while (!done) {
+    numProds++;
+
+    // prod = sequence in product we're currently enumerating
+    let prod = [];
+    for (let i = 0; i < aSequences.length; i++) {
+      prod.push(aSequences[i][seqEltPtrs[i]]);
+    }
+    aCallback(prod);
+
+    // The next sequence in the product differs from the current one by just a
+    // single element.  Determine which element that is.  We advance the
+    // "rightmost" element pointer to the "right" by one.  If we move past the
+    // end of that pointer's sequence, reset the pointer to the first element
+    // in its sequence and then try the sequence to the "left", and so on.
+
+    // seqPtr = index of rightmost input sequence whose element pointer is not
+    // past the end of the sequence
+    let seqPtr = aSequences.length - 1;
+    while (!done) {
+      // Advance the rightmost element pointer.
+      seqEltPtrs[seqPtr]++;
+
+      // The rightmost element pointer is past the end of its sequence.
+      if (seqEltPtrs[seqPtr] >= aSequences[seqPtr].length) {
+        seqEltPtrs[seqPtr] = 0;
+        seqPtr--;
+
+        // All element pointers are past the ends of their sequences.
+        if (seqPtr < 0) {
+          done = true;
+        }
+      } else {
+        break;
+      }
+    }
+  }
+  return numProds;
+}
+
+/**
+ * Enumerates all the subsets in aSet of size aHowMany.  There are
+ * C(aSet.length, aHowMany) such subsets.  aCallback will be passed each subset
+ * as it is generated.  Note that aSet and the subsets enumerated are -- even
+ * though they're arrays -- not sequences; the ordering of their elements is not
+ * important.  Example:
+ *
+ *   choose([1, 2, 3, 4], 2, callback);
+ *   // callback is called C(4, 2) = 6 times with the following sets (arrays):
+ *   // [1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]
+ *
+ * @param  aSet
+ *         an array from which to choose elements, aSet.length > 0
+ * @param  aHowMany
+ *         the number of elements to choose, > 0 and <= aSet.length
+ * @return the total number of sets chosen
+ */
+function choose(aSet, aHowMany, aCallback) {
+  // ptrs = indices of the elements in aSet we're currently choosing
+  var ptrs = [];
+  for (let i = 0; i < aHowMany; i++) {
+    ptrs.push(i);
+  }
+
+  var numFound = 0;
+  var done = false;
+  while (!done) {
+    numFound++;
+    aCallback(ptrs.map(p => aSet[p]));
+
+    // The next subset to be chosen differs from the current one by just a
+    // single element.  Determine which element that is.  Advance the "rightmost"
+    // pointer to the "right" by one.  If we move past the end of set, move the
+    // next non-adjacent rightmost pointer to the right by one, and reset all
+    // succeeding pointers so that they're adjacent to it.  When all pointers
+    // are clustered all the way to the right, we're done.
+
+    // Advance the rightmost pointer.
+    ptrs[ptrs.length - 1]++;
+
+    // The rightmost pointer has gone past the end of set.
+    if (ptrs[ptrs.length - 1] >= aSet.length) {
+      // Find the next rightmost pointer that is not adjacent to the current one.
+      let si = aSet.length - 2; // aSet index
+      let pi = ptrs.length - 2; // ptrs index
+      while (pi >= 0 && ptrs[pi] === si) {
+        pi--;
+        si--;
+      }
+
+      // All pointers are adjacent and clustered all the way to the right.
+      if (pi < 0) {
+        done = true;
+      } else {
+        // pi = index of rightmost pointer with a gap between it and its
+        // succeeding pointer.  Move it right and reset all succeeding pointers
+        // so that they're adjacent to it.
+        ptrs[pi]++;
+        for (let i = 0; i < ptrs.length - pi - 1; i++) {
+          ptrs[i + pi + 1] = ptrs[pi] + i + 1;
+        }
+      }
+    }
+  }
+  return numFound;
+}
+
+/**
+ * Convenience function for nsINavHistoryQuery switches that act as flags.  This
+ * is attached to switch objects.  See querySwitches array above.
+ *
+ * @param  aQuery1
+ *         an nsINavHistoryQuery object
+ * @param  aQuery2
+ *         another nsINavHistoryQuery object
+ * @return true if this switch is the same in both aQuery1 and aQuery2
+ */
+function flagSwitchMatches(aQuery1, aQuery2) {
+  if (aQuery1[this.flag] && aQuery2[this.flag]) {
+    for (let p in this.subswitches) {
+      if (p in aQuery1 && p in aQuery2) {
+        if (aQuery1[p] instanceof Ci.nsIURI) {
+          if (!aQuery1[p].equals(aQuery2[p])) {
+            return false;
+          }
+        } else if (aQuery1[p] !== aQuery2[p]) {
+          return false;
+        }
+      }
+    }
+  } else if (aQuery1[this.flag] || aQuery2[this.flag]) {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Tests if aObj1 and aObj2 are equal.  This function is general and may be used
+ * for either nsINavHistoryQuery or nsINavHistoryQueryOptions objects.  aSwitches
+ * determines which set of switches is used for comparison.  Pass in either
+ * querySwitches or queryOptionSwitches.
+ *
+ * @param  aSwitches
+ *         determines which set of switches applies to aObj1 and aObj2, either
+ *         querySwitches or queryOptionSwitches
+ * @param  aObj1
+ *         an nsINavHistoryQuery or nsINavHistoryQueryOptions object
+ * @param  aObj2
+ *         another nsINavHistoryQuery or nsINavHistoryQueryOptions object
+ * @return true if aObj1 and aObj2 are equal
+ */
+function queryObjsEqual(aSwitches, aObj1, aObj2) {
+  for (let i = 0; i < aSwitches.length; i++) {
+    if (!aSwitches[i].matches(aObj1, aObj2)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+/**
+ * This drives the test runs.  See the comment at the top of this file.
+ *
+ * @param aHowManyLo
+ *        the size of the switch subsets to start with
+ * @param aHowManyHi
+ *        the size of the switch subsets to end with (inclusive)
+ */
+function runQuerySequences(aHowManyLo, aHowManyHi) {
+  var allSwitches = querySwitches.concat(queryOptionSwitches);
+
+  // Choose aHowManyLo switches up to aHowManyHi switches.
+  for (let howMany = aHowManyLo; howMany <= aHowManyHi; howMany++) {
+    let numIters = 0;
+    print("CHOOSING " + howMany + " SWITCHES");
+
+    // Choose all subsets of size howMany from allSwitches.
+    choose(allSwitches, howMany, function (chosenSwitches) {
+      print(numIters);
+      numIters++;
+
+      // Collect the runs.
+      // runs = [ [runs from switch 1], ..., [runs from switch howMany] ]
+      var runs = chosenSwitches.map(function (s) {
+        if (s.desc) {
+          print("  " + s.desc);
+        }
+        return s.runs;
+      });
+
+      // cartProd(runs) => [
+      //   [switch 1 run 1, switch 2 run 1, ..., switch howMany run 1 ],
+      //   ...,
+      //   [switch 1 run 1, switch 2 run 1, ..., switch howMany run N ],
+      //   ..., ...,
+      //   [switch 1 run N, switch 2 run N, ..., switch howMany run 1 ],
+      //   ...,
+      //   [switch 1 run N, switch 2 run N, ..., switch howMany run N ],
+      // ]
+      cartProd(runs, function (runSet) {
+        // Create a new query, apply the switches in runSet, and test it.
+        var query = PlacesUtils.history.getNewQuery();
+        var opts = PlacesUtils.history.getNewQueryOptions();
+        for (let i = 0; i < runSet.length; i++) {
+          runSet[i](query, opts);
+        }
+        serializeDeserialize(query, opts);
+      });
+    });
+  }
+  print("\n");
+}
+
+/**
+ * Serializes the nsINavHistoryQuery objects in aQuery and the
+ * nsINavHistoryQueryOptions object aQueryOptions, de-serializes the
+ * serialization, and ensures (using do_check_* functions) that the
+ * de-serialized objects equal the originals.
+ *
+ * @param aQuery
+ *        an nsINavHistoryQuery object
+ * @param aQueryOptions
+ *        an nsINavHistoryQueryOptions object
+ */
+function serializeDeserialize(aQuery, aQueryOptions) {
+  let queryStr = PlacesUtils.history.queryToQueryString(aQuery, aQueryOptions);
+  print("  " + queryStr);
+  let query2 = {},
+    opts2 = {};
+  PlacesUtils.history.queryStringToQuery(queryStr, query2, opts2);
+  query2 = query2.value;
+  opts2 = opts2.value;
+
+  Assert.ok(queryObjsEqual(querySwitches, aQuery, query2));
+
+  // Finally check the query options objects.
+  Assert.ok(queryObjsEqual(queryOptionSwitches, aQueryOptions, opts2));
+}
+
+/**
+ * Convenience function for switches that have simple values.  This is attached
+ * to switch objects.  See querySwitches and queryOptionSwitches arrays above.
+ *
+ * @param  aObj1
+ *         an nsINavHistoryQuery or nsINavHistoryQueryOptions object
+ * @param  aObj2
+ *         another nsINavHistoryQuery or nsINavHistoryQueryOptions object
+ * @return true if this switch is the same in both aObj1 and aObj2
+ */
+function simplePropertyMatches(aObj1, aObj2) {
+  return aObj1[this.property] === aObj2[this.property];
+}
+
+function run_test() {
+  runQuerySequences(CHOOSE_HOW_MANY_SWITCHES_LO, CHOOSE_HOW_MANY_SWITCHES_HI);
+}
diff --git a/toolkit/components/places/tests/queries/test_query_uri_liveupdate.js b/toolkit/components/places/tests/queries/test_query_uri_liveupdate.js
new file mode 100644
index 0000000000..5ada4a84d4
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_query_uri_liveupdate.js
@@ -0,0 +1,45 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_results_as_tag_query() {
+  let bms = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      { url: "http://tag1.moz.com/", tags: ["tag1"] },
+      { url: "http://tag2.moz.com/", tags: ["tag2"] },
+      { url: "place:tag=tag1" },
+    ],
+  });
+
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid,
+    false,
+    true
+  ).root;
+  Assert.equal(root.childCount, 3, "We should get 3 results");
+  let queryRoot = root.getChild(2);
+  PlacesUtils.asContainer(queryRoot).containerOpen = true;
+
+  Assert.equal(queryRoot.uri, "place:tag=tag1", "Found the query");
+  Assert.equal(queryRoot.childCount, 1, "We should get 1 result");
+  Assert.equal(
+    queryRoot.getChild(0).uri,
+    "http://tag1.moz.com/",
+    "Found the tagged bookmark"
+  );
+
+  await PlacesUtils.bookmarks.update({
+    guid: bms[2].guid,
+    url: "place:tag=tag2",
+  });
+  Assert.equal(queryRoot.uri, "place:tag=tag2", "Found the query");
+  Assert.equal(queryRoot.childCount, 1, "We should get 1 result");
+  Assert.equal(
+    queryRoot.getChild(0).uri,
+    "http://tag2.moz.com/",
+    "Found the tagged bookmark"
+  );
+
+  queryRoot.containerOpen = false;
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_redirects.js b/toolkit/components/places/tests/queries/test_redirects.js
new file mode 100644
index 0000000000..b0e7c9b421
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_redirects.js
@@ -0,0 +1,351 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Array of visits we will add to the database, will be populated later
+// in the test.
+var visits = [];
+
+/**
+ * Takes a sequence of query options, and compare query results obtained through
+ * them with a custom filtered array of visits, based on the values we are
+ * expecting from the query.
+ *
+ * @param  aSequence
+ *         an array that contains query options in the form:
+ *         [includeHidden, maxResults, sortingMode]
+ */
+function check_results_callback(aSequence) {
+  // Sanity check: we should receive 3 parameters.
+  Assert.equal(aSequence.length, 3);
+  let includeHidden = aSequence[0];
+  let maxResults = aSequence[1];
+  let sortingMode = aSequence[2];
+  info(" - - - ");
+  info(
+    "TESTING: includeHidden(" +
+      includeHidden +
+      ")," +
+      " maxResults(" +
+      maxResults +
+      ")," +
+      " sortingMode(" +
+      sortingMode +
+      ")."
+  );
+
+  function isHidden(aVisit) {
+    return (
+      aVisit.transType == Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK ||
+      aVisit.isRedirect
+    );
+  }
+
+  // Build expectedData array.
+  let expectedData = visits.filter(function (aVisit, aIndex, aArray) {
+    // Embed visits never appear in results.
+    if (aVisit.transType == Ci.nsINavHistoryService.TRANSITION_EMBED) {
+      return false;
+    }
+
+    if (!includeHidden && isHidden(aVisit)) {
+      // If the page has any non-hidden visit, then it's visible.
+      if (
+        !visits.filter(function (refVisit) {
+          return refVisit.uri == aVisit.uri && !isHidden(refVisit);
+        }).length
+      ) {
+        return false;
+      }
+    }
+
+    return true;
+  });
+
+  // Remove duplicates, since queries are RESULTS_AS_URI (unique pages).
+  let seen = [];
+  expectedData = expectedData.filter(function (aData) {
+    if (seen.includes(aData.uri)) {
+      return false;
+    }
+    seen.push(aData.uri);
+    return true;
+  });
+
+  // Sort expectedData.
+  function getFirstIndexFor(aEntry) {
+    for (let i = 0; i < visits.length; i++) {
+      if (visits[i].uri == aEntry.uri) {
+        return i;
+      }
+    }
+    return undefined;
+  }
+  function comparator(a, b) {
+    if (sortingMode == Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING) {
+      return b.lastVisit - a.lastVisit;
+    }
+    if (
+      sortingMode == Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_DESCENDING
+    ) {
+      return b.visitCount - a.visitCount;
+    }
+    return getFirstIndexFor(a) - getFirstIndexFor(b);
+  }
+  expectedData.sort(comparator);
+
+  // Crop results to maxResults if it's defined.
+  if (maxResults) {
+    expectedData = expectedData.slice(0, maxResults);
+  }
+
+  // Create a new query with required options.
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.includeHidden = includeHidden;
+  options.sortingMode = sortingMode;
+  if (maxResults) {
+    options.maxResults = maxResults;
+  }
+
+  // Compare resultset with expectedData.
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let root = result.root;
+  root.containerOpen = true;
+  compareArrayToResult(expectedData, root);
+  root.containerOpen = false;
+}
+
+/**
+ * Enumerates all the sequences of the cartesian product of the arrays contained
+ * in aSequences.  Examples:
+ *
+ *   cartProd([[1, 2, 3], ["a", "b"]], callback);
+ *   // callback is called 3 * 2 = 6 times with the following arrays:
+ *   // [1, "a"], [1, "b"], [2, "a"], [2, "b"], [3, "a"], [3, "b"]
+ *
+ *   cartProd([["a"], [1, 2, 3], ["X", "Y"]], callback);
+ *   // callback is called 1 * 3 * 2 = 6 times with the following arrays:
+ *   // ["a", 1, "X"], ["a", 1, "Y"], ["a", 2, "X"], ["a", 2, "Y"],
+ *   // ["a", 3, "X"], ["a", 3, "Y"]
+ *
+ *   cartProd([[1], [2], [3], [4]], callback);
+ *   // callback is called 1 * 1 * 1 * 1 = 1 time with the following array:
+ *   // [1, 2, 3, 4]
+ *
+ *   cartProd([], callback);
+ *   // callback is 0 times
+ *
+ *   cartProd([[1, 2, 3, 4]], callback);
+ *   // callback is called 4 times with the following arrays:
+ *   // [1], [2], [3], [4]
+ *
+ * @param  aSequences
+ *         an array that contains an arbitrary number of arrays
+ * @param  aCallback
+ *         a function that is passed each sequence of the product as it's
+ *         computed
+ * @return the total number of sequences in the product
+ */
+function cartProd(aSequences, aCallback) {
+  if (aSequences.length === 0) {
+    return 0;
+  }
+
+  // For each sequence in aSequences, we maintain a pointer (an array index,
+  // really) to the element we're currently enumerating in that sequence
+  let seqEltPtrs = aSequences.map(i => 0);
+
+  let numProds = 0;
+  let done = false;
+  while (!done) {
+    numProds++;
+
+    // prod = sequence in product we're currently enumerating
+    let prod = [];
+    for (let i = 0; i < aSequences.length; i++) {
+      prod.push(aSequences[i][seqEltPtrs[i]]);
+    }
+    aCallback(prod);
+
+    // The next sequence in the product differs from the current one by just a
+    // single element.  Determine which element that is.  We advance the
+    // "rightmost" element pointer to the "right" by one.  If we move past the
+    // end of that pointer's sequence, reset the pointer to the first element
+    // in its sequence and then try the sequence to the "left", and so on.
+
+    // seqPtr = index of rightmost input sequence whose element pointer is not
+    // past the end of the sequence
+    let seqPtr = aSequences.length - 1;
+    while (!done) {
+      // Advance the rightmost element pointer.
+      seqEltPtrs[seqPtr]++;
+
+      // The rightmost element pointer is past the end of its sequence.
+      if (seqEltPtrs[seqPtr] >= aSequences[seqPtr].length) {
+        seqEltPtrs[seqPtr] = 0;
+        seqPtr--;
+
+        // All element pointers are past the ends of their sequences.
+        if (seqPtr < 0) {
+          done = true;
+        }
+      } else {
+        break;
+      }
+    }
+  }
+  return numProds;
+}
+
+/**
+ * Populate the visits array and add visits to the database.
+ * We will generate visit-chains like:
+ *   visit -> redirect_temp -> redirect_perm
+ */
+add_task(async function test_add_visits_to_database() {
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  // We don't really bother on this, but we need a time to add visits.
+  let timeInMicroseconds = Date.now() * 1000;
+  let visitCount = 1;
+
+  // Array of all possible transition types we could be redirected from.
+  let t = [
+    Ci.nsINavHistoryService.TRANSITION_LINK,
+    Ci.nsINavHistoryService.TRANSITION_TYPED,
+    Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+    // Embed visits are not added to the database and we don't want redirects
+    // to them, thus just avoid addition.
+    // Ci.nsINavHistoryService.TRANSITION_EMBED,
+    Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK,
+    // Would make hard sorting by visit date because last_visit_date is actually
+    // calculated excluding download transitions, but the query includes
+    // downloads.
+    // Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  ];
+
+  function newTimeInMicroseconds() {
+    timeInMicroseconds = timeInMicroseconds - 1000;
+    return timeInMicroseconds;
+  }
+
+  // we add a visit for each of the above transition types.
+  t.forEach(transition =>
+    visits.push({
+      isVisit: true,
+      transType: transition,
+      uri: "http://" + transition + ".example.com/",
+      title: transition + "-example",
+      isRedirect: true,
+      lastVisit: newTimeInMicroseconds(),
+      visitCount:
+        transition == Ci.nsINavHistoryService.TRANSITION_EMBED ||
+        transition == Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK
+          ? 0
+          : visitCount++,
+      isInQuery: true,
+    })
+  );
+
+  // Add a REDIRECT_TEMPORARY layer of visits for each of the above visits.
+  t.forEach(transition =>
+    visits.push({
+      isVisit: true,
+      transType: Ci.nsINavHistoryService.TRANSITION_REDIRECT_TEMPORARY,
+      uri: "http://" + transition + ".redirect.temp.example.com/",
+      title: transition + "-redirect-temp-example",
+      lastVisit: newTimeInMicroseconds(),
+      isRedirect: true,
+      referrer: "http://" + transition + ".example.com/",
+      visitCount: visitCount++,
+      isInQuery: true,
+    })
+  );
+
+  // Add a REDIRECT_PERMANENT layer of visits for each of the above redirects.
+  t.forEach(transition =>
+    visits.push({
+      isVisit: true,
+      transType: Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT,
+      uri: "http://" + transition + ".redirect.perm.example.com/",
+      title: transition + "-redirect-perm-example",
+      lastVisit: newTimeInMicroseconds(),
+      isRedirect: true,
+      referrer: "http://" + transition + ".redirect.temp.example.com/",
+      visitCount: visitCount++,
+      isInQuery: true,
+    })
+  );
+
+  // Add a REDIRECT_PERMANENT layer of visits that loop to the first visit.
+  // These entries should not change visitCount or lastVisit, otherwise
+  // guessing an order would be a nightmare.
+  function getLastValue(aURI, aProperty) {
+    for (let i = 0; i < visits.length; i++) {
+      if (visits[i].uri == aURI) {
+        return visits[i][aProperty];
+      }
+    }
+    do_throw("Unknown uri.");
+    return null;
+  }
+  t.forEach(transition =>
+    visits.push({
+      isVisit: true,
+      transType: Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT,
+      uri: "http://" + transition + ".example.com/",
+      title: getLastValue("http://" + transition + ".example.com/", "title"),
+      lastVisit: getLastValue(
+        "http://" + transition + ".example.com/",
+        "lastVisit"
+      ),
+      isRedirect: true,
+      referrer: "http://" + transition + ".redirect.perm.example.com/",
+      visitCount: getLastValue(
+        "http://" + transition + ".example.com/",
+        "visitCount"
+      ),
+      isInQuery: true,
+    })
+  );
+
+  // Add an unvisited bookmark in the database, it should never appear.
+  visits.push({
+    isBookmark: true,
+    uri: "http://unvisited.bookmark.com/",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    title: "Unvisited Bookmark",
+    isInQuery: false,
+  });
+
+  // Put visits in the database.
+  await task_populateDB(visits);
+});
+
+add_task(async function test_redirects() {
+  // Frecency and hidden are updated asynchronously, wait for them.
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  // This array will be used by cartProd to generate a matrix of all possible
+  // combinations.
+  let includeHidden_options = [true, false];
+  let maxResults_options = [5, 10, 20, null];
+  // These sortingMode are choosen to toggle using special queries for history
+  // menu.
+  let sorting_options = [
+    Ci.nsINavHistoryQueryOptions.SORT_BY_NONE,
+    Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_DESCENDING,
+    Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING,
+  ];
+  // Will execute check_results_callback() for each generated combination.
+  cartProd(
+    [includeHidden_options, maxResults_options, sorting_options],
+    check_results_callback
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/queries/test_result_observeHistoryDetails.js b/toolkit/components/places/tests/queries/test_result_observeHistoryDetails.js
new file mode 100644
index 0000000000..83531ee2c4
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_result_observeHistoryDetails.js
@@ -0,0 +1,155 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures that skipHistoryDetailsNotifications works as expected.
+
+function accumulateNotifications(
+  result,
+  skipHistoryDetailsNotifications = false
+) {
+  let notifications = [];
+  let resultObserver = new Proxy(NavHistoryResultObserver, {
+    get(target, name) {
+      if (name == "check") {
+        result.removeObserver(resultObserver, false);
+        return expectedNotifications =>
+          Assert.deepEqual(notifications, expectedNotifications);
+      }
+      if (name == "skipHistoryDetailsNotifications") {
+        return skipHistoryDetailsNotifications;
+      }
+      // ignore a few uninteresting notifications.
+      if (["QueryInterface", "containerStateChanged"].includes(name)) {
+        return () => {};
+      }
+      return () => {
+        notifications.push(name);
+      };
+    },
+  });
+  result.addObserver(resultObserver, false);
+  return resultObserver;
+}
+
+add_task(async function test_history_query_observe() {
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let notifications = accumulateNotifications(result);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla.org",
+    title: "test",
+  });
+  notifications.check([
+    "nodeHistoryDetailsChanged",
+    "nodeInserted",
+    "nodeTitleChanged",
+  ]);
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_history_query_no_observe() {
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  // Even if we opt-out of notifications, this is an history query, thus the
+  // setting is pretty much ignored.
+  let notifications = accumulateNotifications(result, true);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla.org",
+    title: "test",
+  });
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla2.org",
+    title: "test",
+  });
+
+  notifications.check([
+    "nodeHistoryDetailsChanged",
+    "nodeInserted",
+    "nodeTitleChanged",
+    "nodeHistoryDetailsChanged",
+    "nodeInserted",
+    "nodeTitleChanged",
+  ]);
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_bookmarks_query_observe() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let notifications = accumulateNotifications(result);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+
+  await PlacesUtils.bookmarks.insert({
+    url: "http://mozilla.org",
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "test",
+  });
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla.org",
+    title: "title",
+  });
+
+  notifications.check([
+    "nodeHistoryDetailsChanged",
+    "nodeInserted",
+    "nodeHistoryDetailsChanged",
+  ]);
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_bookmarks_query_no_observe() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let notifications = accumulateNotifications(result, true);
+  let root = PlacesUtils.asContainer(result.root);
+  root.containerOpen = true;
+
+  await PlacesUtils.bookmarks.insert({
+    url: "http://mozilla.org",
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "test",
+  });
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla.org",
+    title: "title",
+  });
+
+  notifications.check(["nodeInserted"]);
+
+  info("Change the sorting mode to one that is based on history");
+  notifications = accumulateNotifications(result, true);
+  result.sortingMode = options.SORT_BY_VISITCOUNT_DESCENDING;
+  notifications.check(["invalidateContainer"]);
+
+  notifications = accumulateNotifications(result, true);
+  await PlacesTestUtils.addVisits({
+    uri: "http://mozilla.org",
+    title: "title",
+  });
+  notifications.check(["nodeHistoryDetailsChanged"]);
+
+  root.containerOpen = false;
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/queries/test_results-as-left-pane.js b/toolkit/components/places/tests/queries/test_results-as-left-pane.js
new file mode 100644
index 0000000000..6cec733758
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_results-as-left-pane.js
@@ -0,0 +1,83 @@
+"use strict";
+
+const expectedRoots = [
+  {
+    title: "OrganizerQueryHistory",
+    uri: `place:sort=${Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING}&type=${Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY}`,
+    guid: "history____v",
+  },
+  {
+    title: "OrganizerQueryDownloads",
+    uri: `place:transition=${Ci.nsINavHistoryService.TRANSITION_DOWNLOAD}&sort=${Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING}`,
+    guid: "downloads__v",
+  },
+  {
+    title: "TagsFolderTitle",
+    uri: `place:sort=${Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING}&type=${Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAGS_ROOT}`,
+    guid: "tags_______v",
+  },
+  {
+    title: "OrganizerQueryAllBookmarks",
+    uri: `place:type=${Ci.nsINavHistoryQueryOptions.RESULTS_AS_ROOTS_QUERY}`,
+    guid: "allbms_____v",
+  },
+];
+
+const placesStrings = Services.strings.createBundle(
+  "chrome://places/locale/places.properties"
+);
+
+function getLeftPaneQuery() {
+  var query = PlacesUtils.history.getNewQuery();
+
+  // Options
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_LEFT_PANE_QUERY;
+
+  // Results
+  var result = PlacesUtils.history.executeQuery(query, options);
+  return result.root;
+}
+
+function assertExpectedChildren(root, expectedChildren) {
+  Assert.equal(
+    root.childCount,
+    expectedChildren.length,
+    "Should have the expected number of children."
+  );
+
+  for (let i = 0; i < root.childCount; i++) {
+    Assert.ok(
+      PlacesTestUtils.ComparePlacesURIs(
+        root.getChild(i).uri,
+        expectedChildren[i].uri
+      ),
+      "Should have the correct uri for root ${i}"
+    );
+    Assert.equal(
+      root.getChild(i).title,
+      placesStrings.GetStringFromName(expectedChildren[i].title),
+      "Should have the correct title for root ${i}"
+    );
+    Assert.equal(root.getChild(i).bookmarkGuid, expectedChildren[i].guid);
+  }
+}
+
+/**
+ * This test will test the basic RESULTS_AS_ROOTS_QUERY, that simply returns,
+ * the existing bookmark roots.
+ */
+add_task(async function test_results_as_root() {
+  let root = getLeftPaneQuery();
+  root.containerOpen = true;
+
+  Assert.equal(
+    PlacesUtils.asQuery(root).queryOptions.queryType,
+    Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS,
+    "Should have a query type of QUERY_TYPE_BOOKMARKS"
+  );
+
+  assertExpectedChildren(root, expectedRoots);
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_results-as-roots.js b/toolkit/components/places/tests/queries/test_results-as-roots.js
new file mode 100644
index 0000000000..2f082d3e0b
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_results-as-roots.js
@@ -0,0 +1,114 @@
+"use strict";
+
+const MOBILE_BOOKMARKS_PREF = "browser.bookmarks.showMobileBookmarks";
+
+const expectedRoots = [
+  {
+    title: "BookmarksToolbarFolderTitle",
+    uri: `place:parent=${PlacesUtils.bookmarks.toolbarGuid}`,
+    guid: PlacesUtils.bookmarks.virtualToolbarGuid,
+  },
+  {
+    title: "BookmarksMenuFolderTitle",
+    uri: `place:parent=${PlacesUtils.bookmarks.menuGuid}`,
+    guid: PlacesUtils.bookmarks.virtualMenuGuid,
+  },
+  {
+    title: "OtherBookmarksFolderTitle",
+    uri: `place:parent=${PlacesUtils.bookmarks.unfiledGuid}`,
+    guid: PlacesUtils.bookmarks.virtualUnfiledGuid,
+  },
+];
+
+const expectedRootsWithMobile = [
+  ...expectedRoots,
+  {
+    title: "MobileBookmarksFolderTitle",
+    uri: `place:parent=${PlacesUtils.bookmarks.mobileGuid}`,
+    guid: PlacesUtils.bookmarks.virtualMobileGuid,
+  },
+];
+
+const placesStrings = Services.strings.createBundle(
+  "chrome://places/locale/places.properties"
+);
+
+function getAllBookmarksQuery() {
+  var query = PlacesUtils.history.getNewQuery();
+
+  // Options
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_VISITCOUNT_ASCENDING;
+  options.resultType = options.RESULTS_AS_ROOTS_QUERY;
+
+  // Results
+  var result = PlacesUtils.history.executeQuery(query, options);
+  return result.root;
+}
+
+function assertExpectedChildren(root, expectedChildren) {
+  Assert.equal(
+    root.childCount,
+    expectedChildren.length,
+    "Should have the expected number of children."
+  );
+
+  for (let i = 0; i < root.childCount; i++) {
+    Assert.equal(
+      root.getChild(i).uri,
+      expectedChildren[i].uri,
+      "Should have the correct uri for root ${i}"
+    );
+    Assert.equal(
+      root.getChild(i).title,
+      placesStrings.GetStringFromName(expectedChildren[i].title),
+      "Should have the correct title for root ${i}"
+    );
+    Assert.equal(root.getChild(i).bookmarkGuid, expectedChildren[i].guid);
+  }
+}
+
+/**
+ * This test will test the basic RESULTS_AS_ROOTS_QUERY, that simply returns,
+ * the existing bookmark roots.
+ */
+add_task(async function test_results_as_root() {
+  let root = getAllBookmarksQuery();
+  root.containerOpen = true;
+
+  Assert.equal(
+    PlacesUtils.asQuery(root).queryOptions.queryType,
+    Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS,
+    "Should have a query type of QUERY_TYPE_BOOKMARKS"
+  );
+
+  assertExpectedChildren(root, expectedRoots);
+
+  root.containerOpen = false;
+});
+
+add_task(async function test_results_as_root_with_mobile() {
+  Services.prefs.setBoolPref(MOBILE_BOOKMARKS_PREF, true);
+
+  let root = getAllBookmarksQuery();
+  root.containerOpen = true;
+
+  assertExpectedChildren(root, expectedRootsWithMobile);
+
+  root.containerOpen = false;
+  Services.prefs.clearUserPref(MOBILE_BOOKMARKS_PREF);
+});
+
+add_task(async function test_results_as_root_remove_mobile_dynamic() {
+  Services.prefs.setBoolPref(MOBILE_BOOKMARKS_PREF, true);
+
+  let root = getAllBookmarksQuery();
+  root.containerOpen = true;
+
+  // Now un-set the pref, and poke the database to update the query.
+  Services.prefs.clearUserPref(MOBILE_BOOKMARKS_PREF);
+
+  assertExpectedChildren(root, expectedRoots);
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_results-as-tag-query.js b/toolkit/components/places/tests/queries/test_results-as-tag-query.js
new file mode 100644
index 0000000000..0d4670b658
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_results-as-tag-query.js
@@ -0,0 +1,63 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const testData = {
+  "http://foo.com/": ["tag1", "tag 2", "Space ☺️ Between"].sort(),
+  "http://bar.com/": ["tag1", "tag 2"].sort(),
+  "http://baz.com/": ["tag 2", "Space ☺️ Between"].sort(),
+  "http://qux.com/": ["Space ☺️ Between"],
+};
+
+const formattedTestData = [];
+for (const [uri, tagArray] of Object.entries(testData)) {
+  formattedTestData.push({
+    title: `Title of ${uri}`,
+    uri,
+    isBookmark: true,
+    isTag: true,
+    tagArray,
+  });
+}
+
+add_task(async function test_results_as_tags_root() {
+  await task_populateDB(formattedTestData);
+
+  // Construct URL - tag mapping from tag query.
+  const actualData = {};
+  for (const uri in testData) {
+    if (testData.hasOwnProperty(uri)) {
+      actualData[uri] = [];
+    }
+  }
+
+  const options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_TAGS_ROOT;
+  const query = PlacesUtils.history.getNewQuery();
+  const root = PlacesUtils.history.executeQuery(query, options).root;
+
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 3, "We should get as many results as tags.");
+  displayResultSet(root);
+
+  for (let i = 0; i < root.childCount; ++i) {
+    const node = root.getChild(i);
+    const tagName = node.title;
+    Assert.equal(
+      node.type,
+      node.RESULT_TYPE_QUERY,
+      "Result type should be RESULT_TYPE_QUERY."
+    );
+    const subRoot = node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+    subRoot.containerOpen = true;
+    for (let j = 0; j < subRoot.childCount; ++j) {
+      actualData[subRoot.getChild(j).uri].push(tagName);
+      actualData[subRoot.getChild(j).uri].sort();
+    }
+  }
+
+  Assert.deepEqual(
+    actualData,
+    testData,
+    "URI-tag mapping should be same from query and initial data."
+  );
+});
diff --git a/toolkit/components/places/tests/queries/test_results-as-visit.js b/toolkit/components/places/tests/queries/test_results-as-visit.js
new file mode 100644
index 0000000000..256e756c98
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_results-as-visit.js
@@ -0,0 +1,158 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+var testData = [];
+var timeInMicroseconds = PlacesUtils.toPRTime(Date.now() - 10000);
+
+function newTimeInMicroseconds() {
+  timeInMicroseconds = timeInMicroseconds + 1000;
+  return timeInMicroseconds;
+}
+
+function createTestData() {
+  function generateVisits(aPage) {
+    for (var i = 0; i < aPage.visitCount; i++) {
+      testData.push({
+        isInQuery: aPage.inQuery,
+        isVisit: true,
+        title: aPage.title,
+        uri: aPage.uri,
+        lastVisit: newTimeInMicroseconds(),
+        isTag: aPage.tags && !!aPage.tags.length,
+        tagArray: aPage.tags,
+      });
+    }
+  }
+
+  var pages = [
+    {
+      uri: "http://foo.com/",
+      title: "amo",
+      tags: ["moz"],
+      visitCount: 3,
+      inQuery: false,
+    },
+    {
+      uri: "http://moilla.com/",
+      title: "bMoz",
+      tags: ["bugzilla"],
+      visitCount: 5,
+      inQuery: true,
+    },
+    {
+      uri: "http://foo.mail.com/changeme1.html",
+      title: "c Moz",
+      visitCount: 7,
+      inQuery: true,
+    },
+    {
+      uri: "http://foo.mail.com/changeme2.html",
+      tags: ["moz"],
+      title: "",
+      visitCount: 1,
+      inQuery: false,
+    },
+    {
+      uri: "http://foo.mail.com/changeme3.html",
+      title: "zydeco",
+      visitCount: 5,
+      inQuery: false,
+    },
+  ];
+  pages.forEach(generateVisits);
+}
+
+/**
+ * This test will test Queries that use relative search terms and URI options
+ */
+add_task(async function test_results_as_visit() {
+  createTestData();
+  await task_populateDB(testData);
+  var query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "moz";
+  query.minVisits = 2;
+
+  // Options
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_VISITCOUNT_ASCENDING;
+  options.resultType = options.RESULTS_AS_VISIT;
+
+  // Results
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+
+  info("Number of items in result set: " + root.childCount);
+  for (let i = 0; i < root.childCount; ++i) {
+    info(
+      "result: " + root.getChild(i).uri + " Title: " + root.getChild(i).title
+    );
+  }
+
+  // Check our inital result set
+  compareArrayToResult(testData, root);
+
+  // If that passes, check liveupdate
+  // Add to the query set
+  info("Adding item to query");
+  var tmp = [];
+  for (let i = 0; i < 2; i++) {
+    tmp.push({
+      isVisit: true,
+      uri: "http://foo.com/added.html",
+      title: "ab moz",
+    });
+  }
+  await task_populateDB(tmp);
+  for (let i = 0; i < 2; i++) {
+    Assert.equal(root.getChild(i).title, "ab moz");
+  }
+
+  // Update an existing URI
+  info("Updating Item");
+  var change2 = [
+    { isVisit: true, title: "moz", uri: "http://foo.mail.com/changeme2.html" },
+  ];
+  await task_populateDB(change2);
+  Assert.ok(nodeInResult(change2, root));
+
+  // Update some visits - add one and take one out of query set, and simply
+  // change one so that it still applies to the query.
+  info("Updating More Items");
+  var change3 = [
+    {
+      isVisit: true,
+      lastVisit: newTimeInMicroseconds(),
+      uri: "http://foo.mail.com/changeme1.html",
+      title: "foo",
+    },
+    {
+      isVisit: true,
+      lastVisit: newTimeInMicroseconds(),
+      uri: "http://foo.mail.com/changeme3.html",
+      title: "moz",
+      isTag: true,
+      tagArray: ["foo", "moz"],
+    },
+  ];
+  await task_populateDB(change3);
+  Assert.ok(!nodeInResult({ uri: "http://foo.mail.com/changeme1.html" }, root));
+  Assert.ok(nodeInResult({ uri: "http://foo.mail.com/changeme3.html" }, root));
+
+  // And now, delete one
+  info("Delete item outside of batch");
+  var change4 = [
+    {
+      isVisit: true,
+      lastVisit: newTimeInMicroseconds(),
+      uri: "http://moilla.com/",
+      title: "mo,z",
+    },
+  ];
+  await task_populateDB(change4);
+  Assert.ok(!nodeInResult(change4, root));
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_searchTerms_includeHidden.js b/toolkit/components/places/tests/queries/test_searchTerms_includeHidden.js
new file mode 100644
index 0000000000..224feb4f0c
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_searchTerms_includeHidden.js
@@ -0,0 +1,74 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Tests the interaction of includeHidden and searchTerms search options.
+
+var timeInMicroseconds = Date.now() * 1000;
+
+const VISITS = [
+  {
+    isVisit: true,
+    transType: TRANSITION_TYPED,
+    uri: "http://redirect.example.com/",
+    title: "example",
+    isRedirect: true,
+    lastVisit: timeInMicroseconds--,
+  },
+  {
+    isVisit: true,
+    transType: TRANSITION_TYPED,
+    uri: "http://target.example.com/",
+    title: "example",
+    lastVisit: timeInMicroseconds--,
+  },
+];
+
+const HIDDEN_VISITS = [
+  {
+    isVisit: true,
+    transType: TRANSITION_FRAMED_LINK,
+    uri: "http://hidden.example.com/",
+    title: "red",
+    lastVisit: timeInMicroseconds--,
+  },
+];
+
+const TEST_DATA = [
+  { searchTerms: "example", includeHidden: true, expectedResults: 2 },
+  { searchTerms: "example", includeHidden: false, expectedResults: 1 },
+  { searchTerms: "red", includeHidden: true, expectedResults: 1 },
+];
+
+add_task(async function test_initalize() {
+  await task_populateDB(VISITS);
+});
+
+add_task(async function test_searchTerms_includeHidden() {
+  for (let data of TEST_DATA) {
+    let query = PlacesUtils.history.getNewQuery();
+    query.searchTerms = data.searchTerms;
+    let options = PlacesUtils.history.getNewQueryOptions();
+    options.includeHidden = data.includeHidden;
+
+    let root = PlacesUtils.history.executeQuery(query, options).root;
+    root.containerOpen = true;
+
+    let cc = root.childCount;
+    // Live update with hidden visits.
+    await task_populateDB(HIDDEN_VISITS);
+    let cc_update = root.childCount;
+
+    root.containerOpen = false;
+
+    Assert.equal(cc, data.expectedResults);
+    Assert.equal(
+      cc_update,
+      data.expectedResults + (data.includeHidden ? 1 : 0)
+    );
+
+    await PlacesUtils.history.remove("http://hidden.example.com/");
+  }
+});
diff --git a/toolkit/components/places/tests/queries/test_searchTerms_time.js b/toolkit/components/places/tests/queries/test_searchTerms_time.js
new file mode 100644
index 0000000000..39fd1353eb
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_searchTerms_time.js
@@ -0,0 +1,109 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test ensures that visitis are correctly live-updated in a history
+// query filtered on searchterms and time.
+
+const USEC_PER_DAY = 86400000000;
+const now = PlacesUtils.toPRTime(new Date());
+
+add_task(async function pages_query() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.beginTime = now - 15 * USEC_PER_DAY;
+  query.endTime = now - 5 * USEC_PER_DAY;
+  query.beginTimeReference = PlacesUtils.history.TIME_RELATIVE_EPOCH;
+  query.endTimeReference = PlacesUtils.history.TIME_RELATIVE_EPOCH;
+  query.searchTerms = "mo";
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_URI_ASCENDING;
+  options.resultType = options.RESULTS_AS_URI;
+  await testQuery(query, options);
+
+  options.sortingMode = options.SORT_BY_DATE_ASCENDING;
+  options.resultType = options.RESULTS_AS_VISITS;
+  await testQuery(query, options);
+});
+
+async function testQuery(query, options) {
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(root.childCount, 0, "There should be zero results initially");
+
+  await PlacesTestUtils.addVisits([
+    // SearchTerms matching URL but out of the timeframe.
+    {
+      url: "https://test.moz.org",
+      title: "abc",
+      visitDate: now - 2 * USEC_PER_DAY,
+    },
+    // In the timeframe but no searchTerms match.
+    {
+      url: "https://test.def.org",
+      title: "def",
+      visitDate: now - 10 * USEC_PER_DAY,
+    },
+    // In the timeframe, matching title.
+    {
+      url: "https://test.ghi.org",
+      title: "amo",
+      visitDate: now - 10 * USEC_PER_DAY,
+    },
+  ]);
+
+  Assert.equal(root.childCount, 1, "Check matching results");
+  let node = root.getChild(0);
+  Assert.equal(node.title, "amo");
+
+  // Change title so it's no longer matching.
+  await PlacesTestUtils.addVisits({
+    url: "https://test.ghi.org",
+    title: "ghi",
+    visitDate: now - 10 * USEC_PER_DAY,
+  });
+
+  Assert.equal(root.childCount, 0, "Check matching results");
+
+  // Add visit in the timeframe.
+  await PlacesTestUtils.addVisits({
+    url: "https://test.moz.org",
+    title: "abc",
+    visitDate: now - 10 * USEC_PER_DAY,
+  });
+
+  Assert.equal(root.childCount, 1, "Check matching results");
+  node = root.getChild(0);
+  Assert.equal(node.title, "abc");
+
+  // Remove visit in the timeframe.
+  await PlacesUtils.history.removeVisitsByFilter({
+    beginDate: PlacesUtils.toDate(now - 15 * USEC_PER_DAY),
+    endDate: PlacesUtils.toDate(now - 5 * USEC_PER_DAY),
+  });
+  await PlacesTestUtils.dumpTable({
+    table: "moz_places",
+    columns: ["id", "url"],
+  });
+  await PlacesTestUtils.dumpTable({
+    table: "moz_historyvisits",
+    columns: ["place_id", "visit_date"],
+  });
+
+  Assert.equal(root.childCount, 0, "Check matching results");
+
+  // Add matching visit out of the timeframe.
+  await PlacesTestUtils.addVisits(
+    // SearchTerms matching URL but out of the timeframe.
+    {
+      url: "https://test.mozilla.org",
+      title: "mozilla",
+      visitDate: now - 2 * USEC_PER_DAY,
+    }
+  );
+
+  Assert.equal(root.childCount, 0, "Check matching results");
+
+  root.containerOpen = false;
+  await PlacesUtils.history.clear();
+}
diff --git a/toolkit/components/places/tests/queries/test_search_tags.js b/toolkit/components/places/tests/queries/test_search_tags.js
new file mode 100644
index 0000000000..4f8cface07
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_search_tags.js
@@ -0,0 +1,73 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_search_for_tagged_bookmarks() {
+  const testURI = "http://a1.com";
+
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "bug 395101 test",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: folder.guid,
+    title: "1 title",
+    url: testURI,
+  });
+
+  // tag the bookmarked URI
+  PlacesUtils.tagging.tagURI(uri(testURI), [
+    "elephant",
+    "walrus",
+    "giraffe",
+    "turkey",
+    "hiPPo",
+    "BABOON",
+    "alf",
+  ]);
+
+  // search for the bookmark, using a tag
+  var query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "elephant";
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  query.setParents([folder.guid]);
+
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var rootNode = result.root;
+  rootNode.containerOpen = true;
+
+  Assert.equal(rootNode.childCount, 1);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, bookmark.guid);
+  rootNode.containerOpen = false;
+
+  // partial matches are okay
+  query.searchTerms = "wal";
+  result = PlacesUtils.history.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 1);
+  rootNode.containerOpen = false;
+
+  // case insensitive search term
+  query.searchTerms = "WALRUS";
+  result = PlacesUtils.history.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 1);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, bookmark.guid);
+  rootNode.containerOpen = false;
+
+  // case insensitive tag
+  query.searchTerms = "baboon";
+  result = PlacesUtils.history.executeQuery(query, options);
+  rootNode = result.root;
+  rootNode.containerOpen = true;
+  Assert.equal(rootNode.childCount, 1);
+  Assert.equal(rootNode.getChild(0).bookmarkGuid, bookmark.guid);
+  rootNode.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_searchterms-bookmarklets.js b/toolkit/components/places/tests/queries/test_searchterms-bookmarklets.js
new file mode 100644
index 0000000000..8eebf68cad
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_searchterms-bookmarklets.js
@@ -0,0 +1,63 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Check that bookmarklets are returned by searches with searchTerms.
+
+var testData = [
+  {
+    isInQuery: true,
+    isBookmark: true,
+    title: "bookmark 1",
+    uri: "http://mozilla.org/script/",
+  },
+
+  {
+    isInQuery: true,
+    isBookmark: true,
+    title: "bookmark 2",
+    uri: "javascript:alert('moz');",
+  },
+];
+
+add_task(async function test_initalize() {
+  await task_populateDB(testData);
+});
+
+add_test(function test_search_by_title() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "bookmark";
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  compareArrayToResult(testData, root);
+  root.containerOpen = false;
+
+  run_next_test();
+});
+
+add_test(function test_search_by_schemeToken() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "script";
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  compareArrayToResult(testData, root);
+  root.containerOpen = false;
+
+  run_next_test();
+});
+
+add_test(function test_search_by_uriAndTitle() {
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "moz";
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  compareArrayToResult(testData, root);
+  root.containerOpen = false;
+
+  run_next_test();
+});
diff --git a/toolkit/components/places/tests/queries/test_searchterms-domain.js b/toolkit/components/places/tests/queries/test_searchterms-domain.js
new file mode 100644
index 0000000000..45a0a7d542
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_searchterms-domain.js
@@ -0,0 +1,197 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The test data for our database, note that the ordering of the results that
+// will be returned by the query (the isInQuery: true objects) is IMPORTANT.
+// see compareArrayToResult in head_queries.js for more info.
+var testData = [
+  // Test ftp protocol - vary the title length, embed search term
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    uri: "ftp://foo.com/ftp",
+    lastVisit: lastweek,
+    title: "hugelongconfmozlagurationofwordswithasearchtermsinit whoo-hoo",
+  },
+
+  // Test flat domain with annotation, search term in sentence
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    isPageAnnotation: true,
+    uri: "http://foo.com/",
+    annoName: "moz/test",
+    annoVal: "val",
+    lastVisit: lastweek,
+    title: "you know, moz is cool",
+  },
+
+  // Test subdomain included with isRedirect=true, different transtype
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    title: "amozzie",
+    isRedirect: true,
+    uri: "http://mail.foo.com/redirect",
+    lastVisit: old,
+    referrer: "http://myreferrer.com",
+    transType: PlacesUtils.history.TRANSITION_LINK,
+  },
+
+  // Test subdomain inclued, search term at end
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    uri: "http://mail.foo.com/yiihah",
+    title: "blahmoz",
+    lastVisit: daybefore,
+  },
+
+  // Test www. style URI is included, with a tag
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    isTag: true,
+    uri: "http://www.foo.com/yiihah",
+    tagArray: ["moz"],
+    lastVisit: yesterday,
+    title: "foo",
+  },
+
+  // Test https protocol
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    title: "moz",
+    uri: "https://foo.com/",
+    lastVisit: today,
+  },
+
+  // Begin the invalid queries: wrong search term
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m o z",
+    uri: "http://foo.com/tooearly.php",
+    lastVisit: today,
+  },
+
+  // Test bad URI
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "moz",
+    uri: "http://sffoo.com/justwrong.htm",
+    lastVisit: yesterday,
+  },
+
+  // Test what we do with escaping in titles
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m%0o%0z",
+    uri: "http://foo.com/changeme1.htm",
+    lastVisit: yesterday,
+  },
+
+  // Test another invalid title - for updating later
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m,oz",
+    uri: "http://foo.com/changeme2.htm",
+    lastVisit: yesterday,
+  },
+];
+
+/**
+ * This test will test Queries that use relative search terms and domain options
+ */
+add_task(async function test_searchterms_domain() {
+  await task_populateDB(testData);
+  var query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "moz";
+  query.domain = "foo.com";
+  query.domainIsHost = false;
+
+  // Options
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_ASCENDING;
+  options.resultType = options.RESULTS_AS_URI;
+
+  // Results
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+
+  info("Number of items in result set: " + root.childCount);
+  for (var i = 0; i < root.childCount; ++i) {
+    info(
+      "result: " + root.getChild(i).uri + " Title: " + root.getChild(i).title
+    );
+  }
+
+  // Check our inital result set
+  compareArrayToResult(testData, root);
+
+  // If that passes, check liveupdate
+  // Add to the query set
+  info("Adding item to query");
+  var change1 = [
+    {
+      isVisit: true,
+      isDetails: true,
+      uri: "http://foo.com/added.htm",
+      title: "moz",
+      transType: PlacesUtils.history.TRANSITION_LINK,
+    },
+  ];
+  await task_populateDB(change1);
+  Assert.ok(nodeInResult(change1, root));
+
+  // Update an existing URI
+  info("Updating Item");
+  var change2 = [
+    { isDetails: true, uri: "http://foo.com/changeme1.htm", title: "moz" },
+  ];
+  await task_populateDB(change2);
+  Assert.ok(nodeInResult(change2, root));
+
+  // Add one and take one out of query set, and simply change one so that it
+  // still applies to the query.
+  info("Updating More Items");
+  var change3 = [
+    { isDetails: true, uri: "http://foo.com/changeme2.htm", title: "moz" },
+    {
+      isDetails: true,
+      uri: "http://mail.foo.com/yiihah",
+      title: "moz now updated",
+    },
+    { isDetails: true, uri: "ftp://foo.com/ftp", title: "gone" },
+  ];
+  await task_populateDB(change3);
+  Assert.ok(nodeInResult({ uri: "http://foo.com/changeme2.htm" }, root));
+  Assert.ok(nodeInResult({ uri: "http://mail.foo.com/yiihah" }, root));
+  Assert.ok(!nodeInResult({ uri: "ftp://foo.com/ftp" }, root));
+
+  // And now, delete one
+  info("Deleting items");
+  var change4 = [{ isDetails: true, uri: "https://foo.com/", title: "mo,z" }];
+  await task_populateDB(change4);
+  Assert.ok(!nodeInResult(change4, root));
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_searchterms-uri.js b/toolkit/components/places/tests/queries/test_searchterms-uri.js
new file mode 100644
index 0000000000..27b9a28c71
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_searchterms-uri.js
@@ -0,0 +1,125 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// The test data for our database, note that the ordering of the results that
+// will be returned by the query (the isInQuery: true objects) is IMPORTANT.
+// see compareArrayToResult in head_queries.js for more info.
+var testData = [
+  // Test flat domain with annotation, search term in sentence
+  {
+    isInQuery: true,
+    isVisit: true,
+    isDetails: true,
+    isPageAnnotation: true,
+    uri: "http://foo.com/",
+    annoName: "moz/test",
+    annoVal: "val",
+    lastVisit: lastweek,
+    title: "you know, moz is cool",
+  },
+
+  // Test https protocol
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "moz",
+    uri: "https://foo.com/",
+    lastVisit: today,
+  },
+
+  // Begin the invalid queries: wrong search term
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m o z",
+    uri: "http://foo.com/wrongsearch.php",
+    lastVisit: today,
+  },
+
+  // Test subdomain inclued, search term at end
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    uri: "http://mail.foo.com/yiihah",
+    title: "blahmoz",
+    lastVisit: daybefore,
+  },
+
+  // Test ftp protocol - vary the title length, embed search term
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    uri: "ftp://foo.com/ftp",
+    lastVisit: lastweek,
+    title: "hugelongconfmozlagurationofwordswithasearchtermsinit whoo-hoo",
+  },
+
+  // Test what we do with escaping in titles
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m%0o%0z",
+    uri: "http://foo.com/changeme1.htm",
+    lastVisit: yesterday,
+  },
+
+  // Test another invalid title - for updating later
+  {
+    isInQuery: false,
+    isVisit: true,
+    isDetails: true,
+    title: "m,oz",
+    uri: "http://foo.com/changeme2.htm",
+    lastVisit: yesterday,
+  },
+];
+
+/**
+ * This test will test Queries that use relative search terms and URI options
+ */
+add_task(async function test_searchterms_uri() {
+  await task_populateDB(testData);
+  var query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = "moz";
+  query.uri = uri("http://foo.com");
+
+  // Options
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_ASCENDING;
+  options.resultType = options.RESULTS_AS_URI;
+
+  // Results
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+
+  info("Number of items in result set: " + root.childCount);
+  for (var i = 0; i < root.childCount; ++i) {
+    info(
+      "result: " + root.getChild(i).uri + " Title: " + root.getChild(i).title
+    );
+  }
+
+  // Check our inital result set
+  compareArrayToResult(testData, root);
+
+  // live update.
+  info("change title");
+  var change1 = [{ isDetails: true, uri: "http://foo.com/", title: "mo" }];
+  await task_populateDB(change1);
+
+  Assert.ok(!nodeInResult({ uri: "http://foo.com/" }, root));
+  var change2 = [{ isDetails: true, uri: "http://foo.com/", title: "moz" }];
+  await task_populateDB(change2);
+  Assert.ok(nodeInResult({ uri: "http://foo.com/" }, root));
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/queries/test_sort-date-site-grouping.js b/toolkit/components/places/tests/queries/test_sort-date-site-grouping.js
new file mode 100644
index 0000000000..358ab45fdb
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_sort-date-site-grouping.js
@@ -0,0 +1,223 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* ***** BEGIN LICENSE BLOCK *****
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+ * ***** END LICENSE BLOCK ***** */
+
+// This test ensures that the date and site type of |place:| query maintains
+// its quantifications correctly. Namely, it ensures that the date part of the
+// query is not lost when the domain queries are made.
+
+// We specifically craft these entries so that if a by Date and Site sorting is
+// applied, we find one domain in the today range, and two domains in the older
+// than six months range.
+// The correspondence between item in |testData| and date range is stored in
+// leveledTestData.
+var testData = [
+  {
+    isVisit: true,
+    uri: "file:///directory/1",
+    lastVisit: today,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/1",
+    lastVisit: today,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/2",
+    lastVisit: today,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "file:///directory/2",
+    lastVisit: olderthansixmonths,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/3",
+    lastVisit: olderthansixmonths,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/4",
+    lastVisit: olderthansixmonths,
+    title: "test visit",
+    isInQuery: true,
+  },
+  {
+    isVisit: true,
+    uri: "http://example.net/1",
+    lastVisit: olderthansixmonths + 1000,
+    title: "test visit",
+    isInQuery: true,
+  },
+];
+var leveledTestData = [
+  // Today
+  [
+    [0], // Today, local files
+    [1, 2],
+  ], // Today, example.com
+  // Older than six months
+  [
+    [3], // Older than six months, local files
+    [4, 5], // Older than six months, example.com
+    [6], // Older than six months, example.net
+  ],
+];
+
+// This test data is meant for live updating. The |levels| property indicates
+// date range index and then domain index.
+var testDataAddedLater = [
+  {
+    isVisit: true,
+    uri: "http://example.com/5",
+    lastVisit: olderthansixmonths,
+    title: "test visit",
+    isInQuery: true,
+    levels: [1, 1],
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/6",
+    lastVisit: olderthansixmonths,
+    title: "test visit",
+    isInQuery: true,
+    levels: [1, 1],
+  },
+  {
+    isVisit: true,
+    uri: "http://example.com/7",
+    lastVisit: today,
+    title: "test visit",
+    isInQuery: true,
+    levels: [0, 1],
+  },
+  {
+    isVisit: true,
+    uri: "file:///directory/3",
+    lastVisit: today,
+    title: "test visit",
+    isInQuery: true,
+    levels: [0, 0],
+  },
+];
+
+add_task(async function test_sort_date_site_grouping() {
+  await task_populateDB(testData);
+
+  // On Linux, the (local files) folder is shown after sites unlike Mac/Windows.
+  // Thus, we avoid running this test on Linux but this should be re-enabled
+  // after bug 624024 is resolved.
+  let isLinux = "@mozilla.org/gnome-gconf-service;1" in Cc;
+  if (isLinux) {
+    return;
+  }
+
+  // In this test, there are three levels of results:
+  // 1st: Date queries. e.g., today, last week, or older than 6 months.
+  // 2nd: Domain queries restricted to a date. e.g. mozilla.com today.
+  // 3rd: Actual visits. e.g. mozilla.com/index.html today.
+  //
+  // We store all the third level result roots so that we can easily close all
+  // containers and test live updating into specific results.
+  let roots = [];
+
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY;
+
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  // This corresponds to the number of date ranges.
+  Assert.equal(root.childCount, leveledTestData.length);
+
+  // We pass off to |checkFirstLevel| to check the first level of results.
+  for (let index = 0; index < leveledTestData.length; index++) {
+    let node = root.getChild(index);
+    checkFirstLevel(index, node, roots);
+  }
+
+  // Test live updating.
+  for (let visit of testDataAddedLater) {
+    await task_populateDB([visit]);
+    let oldLength = testData.length;
+    let i = visit.levels[0];
+    let j = visit.levels[1];
+    testData.push(visit);
+    leveledTestData[i][j].push(oldLength);
+    compareArrayToResult(
+      leveledTestData[i][j].map(x => testData[x]),
+      roots[i][j]
+    );
+  }
+
+  for (let i = 0; i < roots.length; i++) {
+    for (let j = 0; j < roots[i].length; j++) {
+      roots[i][j].containerOpen = false;
+    }
+  }
+
+  root.containerOpen = false;
+});
+
+function checkFirstLevel(index, node, roots) {
+  PlacesUtils.asContainer(node).containerOpen = true;
+
+  Assert.ok(PlacesUtils.nodeIsDay(node));
+  PlacesUtils.asQuery(node);
+  let query = node.query;
+  let options = node.queryOptions;
+
+  Assert.ok(query.hasBeginTime && query.hasEndTime);
+
+  // Here we check the second level of results.
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  roots.push([]);
+  root.containerOpen = true;
+
+  Assert.equal(root.childCount, leveledTestData[index].length);
+  for (var secondIndex = 0; secondIndex < root.childCount; secondIndex++) {
+    let child = PlacesUtils.asQuery(root.getChild(secondIndex));
+    checkSecondLevel(index, secondIndex, child, roots);
+  }
+  root.containerOpen = false;
+  node.containerOpen = false;
+}
+
+function checkSecondLevel(index, secondIndex, child, roots) {
+  let query = child.query;
+  let options = child.queryOptions;
+
+  Assert.ok(query.hasDomain);
+  Assert.ok(query.hasBeginTime && query.hasEndTime);
+
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  // We should now have that roots[index][secondIndex] is set to the second
+  // level's results root.
+  roots[index].push(root);
+
+  // We pass off to compareArrayToResult to check the third level of
+  // results.
+  root.containerOpen = true;
+  compareArrayToResult(
+    leveledTestData[index][secondIndex].map(x => testData[x]),
+    root
+  );
+  // We close |root|'s container later so that we can test live
+  // updates into it.
+}
diff --git a/toolkit/components/places/tests/queries/test_sorting.js b/toolkit/components/places/tests/queries/test_sorting.js
new file mode 100644
index 0000000000..41059c0823
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_sorting.js
@@ -0,0 +1,961 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var tests = [];
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_NONE,
+
+  async setup() {
+    info("Sorting test 1: SORT BY NONE");
+
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://example.com/b",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "y",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "z",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "x",
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = this._unsortedData;
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    // no reverse sorting for SORT BY NONE
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING,
+
+  async setup() {
+    info("Sorting test 2: SORT BY TITLE");
+
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://example.com/b1",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "y",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "z",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "x",
+        isInQuery: true,
+      },
+
+      // if titles are equal, should fall back to URI
+      {
+        isBookmark: true,
+        uri: "http://example.com/b2",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "y",
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[2],
+      this._unsortedData[0],
+      this._unsortedData[3],
+      this._unsortedData[1],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING,
+
+  async setup() {
+    info("Sorting test 3: SORT BY DATE");
+
+    var timeInMicroseconds = Date.now() * 1000;
+    this._unsortedData = [
+      {
+        isVisit: true,
+        isDetails: true,
+        isBookmark: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 0,
+        uri: "http://example.com/c1",
+        lastVisit: timeInMicroseconds - 2000,
+        title: "x1",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        isBookmark: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 1,
+        uri: "http://example.com/a",
+        lastVisit: timeInMicroseconds - 1000,
+        title: "z",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        isBookmark: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 2,
+        uri: "http://example.com/b",
+        lastVisit: timeInMicroseconds - 3000,
+        title: "y",
+        isInQuery: true,
+      },
+
+      // if dates are equal, should fall back to title
+      {
+        isVisit: true,
+        isDetails: true,
+        isBookmark: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 3,
+        uri: "http://example.com/c2",
+        lastVisit: timeInMicroseconds - 2000,
+        title: "x2",
+        isInQuery: true,
+      },
+
+      // if dates and title are equal, should fall back to bookmark index
+      {
+        isVisit: true,
+        isDetails: true,
+        isBookmark: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 4,
+        uri: "http://example.com/c2",
+        lastVisit: timeInMicroseconds - 2000,
+        title: "x2",
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[2],
+      this._unsortedData[0],
+      this._unsortedData[3],
+      this._unsortedData[4],
+      this._unsortedData[1],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_URI_ASCENDING,
+
+  async setup() {
+    info("Sorting test 4: SORT BY URI");
+
+    var timeInMicroseconds = Date.now() * 1000;
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        isDetails: true,
+        lastVisit: timeInMicroseconds,
+        uri: "http://example.com/b",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 0,
+        title: "y",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 1,
+        title: "x",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 2,
+        title: "z",
+        isInQuery: true,
+      },
+
+      // if URIs are equal, should fall back to date
+      {
+        isBookmark: true,
+        isDetails: true,
+        lastVisit: timeInMicroseconds + 1000,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 3,
+        title: "x",
+        isInQuery: true,
+      },
+
+      // if no URI (e.g., node is a folder), should fall back to title
+      {
+        isFolder: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 4,
+        title: "y",
+        isInQuery: true,
+      },
+
+      // if URIs and dates are equal, should fall back to bookmark index
+      {
+        isBookmark: true,
+        isDetails: true,
+        lastVisit: timeInMicroseconds + 1000,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 5,
+        title: "x",
+        isInQuery: true,
+      },
+
+      // if no URI and titles are equal, should fall back to bookmark index
+      {
+        isFolder: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 6,
+        title: "y",
+        isInQuery: true,
+      },
+
+      // if no URI and titles are equal, should fall back to title
+      {
+        isFolder: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 7,
+        title: "z",
+        isInQuery: true,
+      },
+
+      // Separator should go after folders.
+      {
+        isSeparator: true,
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 8,
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[4],
+      this._unsortedData[6],
+      this._unsortedData[7],
+      this._unsortedData[8],
+      this._unsortedData[2],
+      this._unsortedData[0],
+      this._unsortedData[1],
+      this._unsortedData[3],
+      this._unsortedData[5],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_URI_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_ASCENDING,
+
+  async setup() {
+    info("Sorting test 5: SORT BY VISITCOUNT");
+
+    var timeInMicroseconds = Date.now() * 1000;
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        lastVisit: timeInMicroseconds,
+        title: "z",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 0,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        lastVisit: timeInMicroseconds,
+        title: "x",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 1,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/b1",
+        lastVisit: timeInMicroseconds,
+        title: "y1",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 2,
+        isInQuery: true,
+      },
+
+      // if visitCounts are equal, should fall back to date
+      {
+        isBookmark: true,
+        uri: "http://example.com/b2",
+        lastVisit: timeInMicroseconds + 1000,
+        title: "y2a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 3,
+        isInQuery: true,
+      },
+
+      // if visitCounts and dates are equal, should fall back to bookmark index
+      {
+        isBookmark: true,
+        uri: "http://example.com/b2",
+        lastVisit: timeInMicroseconds + 1000,
+        title: "y2b",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 4,
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[0],
+      this._unsortedData[2],
+      this._unsortedData[3],
+      this._unsortedData[4],
+      this._unsortedData[1],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+    // add visits to increase visit count
+    await PlacesTestUtils.addVisits([
+      {
+        uri: uri("http://example.com/a"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+      {
+        uri: uri("http://example.com/b1"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+      {
+        uri: uri("http://example.com/b1"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+      {
+        uri: uri("http://example.com/b2"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds + 1000,
+      },
+      {
+        uri: uri("http://example.com/b2"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds + 1000,
+      },
+      {
+        uri: uri("http://example.com/c"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+      {
+        uri: uri("http://example.com/c"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+      {
+        uri: uri("http://example.com/c"),
+        transition: TRANSITION_TYPED,
+        visitDate: timeInMicroseconds,
+      },
+    ]);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode =
+      Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_ASCENDING,
+
+  async setup() {
+    info("Sorting test 7: SORT BY DATEADDED");
+
+    var timeInMicroseconds = Date.now() * 1000;
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://example.com/b1",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 0,
+        title: "y1",
+        dateAdded: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 1,
+        title: "z",
+        dateAdded: timeInMicroseconds - 2000,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 2,
+        title: "x",
+        dateAdded: timeInMicroseconds,
+        isInQuery: true,
+      },
+
+      // if dateAddeds are equal, should fall back to title
+      {
+        isBookmark: true,
+        uri: "http://example.com/b2",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 3,
+        title: "y2",
+        dateAdded: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+
+      // if dateAddeds and titles are equal, should fall back to bookmark index
+      {
+        isBookmark: true,
+        uri: "http://example.com/b3",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 4,
+        title: "y3",
+        dateAdded: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[1],
+      this._unsortedData[0],
+      this._unsortedData[3],
+      this._unsortedData[4],
+      this._unsortedData[2],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode =
+      Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_LASTMODIFIED_ASCENDING,
+
+  async setup() {
+    info("Sorting test 8: SORT BY LASTMODIFIED");
+
+    var timeInMicroseconds = Date.now() * 1000;
+    var timeAddedInMicroseconds = timeInMicroseconds - 10000;
+
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://example.com/b1",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 0,
+        title: "y1",
+        dateAdded: timeAddedInMicroseconds,
+        lastModified: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/a",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 1,
+        title: "z",
+        dateAdded: timeAddedInMicroseconds,
+        lastModified: timeInMicroseconds - 2000,
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://example.com/c",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 2,
+        title: "x",
+        dateAdded: timeAddedInMicroseconds,
+        lastModified: timeInMicroseconds,
+        isInQuery: true,
+      },
+
+      // if lastModifieds are equal, should fall back to title
+      {
+        isBookmark: true,
+        uri: "http://example.com/b2",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 3,
+        title: "y2",
+        dateAdded: timeAddedInMicroseconds,
+        lastModified: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+
+      // if lastModifieds and titles are equal, should fall back to bookmark
+      // index
+      {
+        isBookmark: true,
+        uri: "http://example.com/b3",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: 4,
+        title: "y3",
+        dateAdded: timeAddedInMicroseconds,
+        lastModified: timeInMicroseconds - 1000,
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[1],
+      this._unsortedData[0],
+      this._unsortedData[3],
+      this._unsortedData[4],
+      this._unsortedData[2],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode =
+      Ci.nsINavHistoryQueryOptions.SORT_BY_LASTMODIFIED_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_TAGS_ASCENDING,
+
+  async setup() {
+    info("Sorting test 9: SORT BY TAGS");
+
+    this._unsortedData = [
+      {
+        isBookmark: true,
+        uri: "http://url2.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title x",
+        isTag: true,
+        tagArray: ["x", "y", "z"],
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://url1a.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title y1",
+        isTag: true,
+        tagArray: ["a", "b"],
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://url3a.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title w1",
+        isInQuery: true,
+      },
+
+      {
+        isBookmark: true,
+        uri: "http://url0.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title z",
+        isTag: true,
+        tagArray: ["a", "y", "z"],
+        isInQuery: true,
+      },
+
+      // if tags are equal, should fall back to title
+      {
+        isBookmark: true,
+        uri: "http://url1b.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title y2",
+        isTag: true,
+        tagArray: ["b", "a"],
+        isInQuery: true,
+      },
+
+      // if tags are equal, should fall back to title
+      {
+        isBookmark: true,
+        uri: "http://url3b.com/",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+        title: "title w2",
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[2],
+      this._unsortedData[5],
+      this._unsortedData[1],
+      this._unsortedData[4],
+      this._unsortedData[3],
+      this._unsortedData[0],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    // Query
+    var query = PlacesUtils.history.getNewQuery();
+    query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+
+    // query options
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    // Results - this gets the result set and opens it for reading and modification.
+    var result = PlacesUtils.history.executeQuery(query, options);
+    var root = result.root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_TAGS_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+// SORT_BY_FRECENCY_*
+
+tests.push({
+  _sortingMode: Ci.nsINavHistoryQueryOptions.SORT_BY_FRECENCY_ASCENDING,
+
+  async setup() {
+    info("Sorting test 13: SORT BY FRECENCY ");
+
+    let timeInMicroseconds = PlacesUtils.toPRTime(Date.now() - 10000);
+
+    function newTimeInMicroseconds() {
+      timeInMicroseconds = timeInMicroseconds + 1000;
+      return timeInMicroseconds;
+    }
+
+    this._unsortedData = [
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://moz.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "I",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://moz.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "I",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://moz.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "I",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://is.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "love",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://best.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "moz",
+        isInQuery: true,
+      },
+
+      {
+        isVisit: true,
+        isDetails: true,
+        uri: "http://best.com/",
+        lastVisit: newTimeInMicroseconds(),
+        title: "moz",
+        isInQuery: true,
+      },
+    ];
+
+    this._sortedData = [
+      this._unsortedData[3],
+      this._unsortedData[5],
+      this._unsortedData[2],
+    ];
+
+    // This function in head_queries.js creates our database with the above data
+    await task_populateDB(this._unsortedData);
+  },
+
+  check() {
+    var query = PlacesUtils.history.getNewQuery();
+    var options = PlacesUtils.history.getNewQueryOptions();
+    options.sortingMode = this._sortingMode;
+
+    var root = PlacesUtils.history.executeQuery(query, options).root;
+    root.containerOpen = true;
+    compareArrayToResult(this._sortedData, root);
+    root.containerOpen = false;
+  },
+
+  check_reverse() {
+    this._sortingMode =
+      Ci.nsINavHistoryQueryOptions.SORT_BY_FRECENCY_DESCENDING;
+    this._sortedData.reverse();
+    this.check();
+  },
+});
+
+add_task(async function test_sorting() {
+  for (let test of tests) {
+    await test.setup();
+    await PlacesTestUtils.promiseAsyncUpdates();
+    test.check();
+    // sorting reversed, usually SORT_BY have ASC and DESC
+    test.check_reverse();
+    // Execute cleanup tasks
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesUtils.history.clear();
+  }
+});
diff --git a/toolkit/components/places/tests/queries/test_tags.js b/toolkit/components/places/tests/queries/test_tags.js
new file mode 100644
index 0000000000..17ad3478ce
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_tags.js
@@ -0,0 +1,626 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Tests bookmark queries with tags.  See bug 399799.
+ */
+
+"use strict";
+
+add_task(async function tags_getter_setter() {
+  info("Tags getter/setter should work correctly");
+  info("Without setting tags, tags getter should return empty array");
+  var [query] = makeQuery();
+  Assert.equal(query.tags.length, 0);
+
+  info("Setting tags to an empty array, tags getter should return empty array");
+  [query] = makeQuery([]);
+  Assert.equal(query.tags.length, 0);
+
+  info("Setting a few tags, tags getter should return correct array");
+  var tags = ["bar", "baz", "foo"];
+  [query] = makeQuery(tags);
+  setsAreEqual(query.tags, tags, true);
+
+  info("Setting some dupe tags, tags getter return unique tags");
+  [query] = makeQuery(["foo", "foo", "bar", "foo", "baz", "bar"]);
+  setsAreEqual(query.tags, ["bar", "baz", "foo"], true);
+});
+
+add_task(async function invalid_setter_calls() {
+  info("Invalid calls to tags setter should fail");
+  try {
+    var query = PlacesUtils.history.getNewQuery();
+    query.tags = null;
+    do_throw("Passing null to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    query = PlacesUtils.history.getNewQuery();
+    query.tags = "this should not work";
+    do_throw("Passing a string to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery([null]);
+    do_throw("Passing one-element array with null to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery([undefined]);
+    do_throw("Passing one-element array with undefined to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery(["foo", null, "bar"]);
+    do_throw("Passing mixture of tags and null to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery(["foo", undefined, "bar"]);
+    do_throw("Passing mixture of tags and undefined to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery([1, 2, 3]);
+    do_throw("Passing numbers to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery(["foo", 1, 2, 3]);
+    do_throw("Passing mixture of tags and numbers to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    var str = PlacesUtils.toISupportsString("foo");
+    query = PlacesUtils.history.getNewQuery();
+    query.tags = str;
+    do_throw("Passing nsISupportsString to SetTags should fail");
+  } catch (exc) {}
+
+  try {
+    makeQuery([str]);
+    do_throw("Passing array of nsISupportsStrings to SetTags should fail");
+  } catch (exc) {}
+});
+
+add_task(async function not_setting_tags() {
+  info("Not setting tags at all should not affect query URI");
+  checkQueryURI();
+});
+
+add_task(async function empty_array_tags() {
+  info("Setting tags with an empty array should not affect query URI");
+  checkQueryURI([]);
+});
+
+add_task(async function set_tags() {
+  info("Setting some tags should result in correct query URI");
+  checkQueryURI([
+    "foo",
+    "七難",
+    "",
+    "いっぱいおっぱい",
+    "Abracadabra",
+    "１２３",
+    "Here's a pretty long tag name with some = signs and 1 2 3s and spaces oh jeez will it work I hope so!",
+    "アスキーでございません",
+    "あいうえお",
+  ]);
+});
+
+add_task(async function no_tags_tagsAreNot() {
+  info(
+    "Not setting tags at all but setting tagsAreNot should " +
+      "affect query URI"
+  );
+  checkQueryURI(null, true);
+});
+
+add_task(async function empty_array_tags_tagsAreNot() {
+  info(
+    "Setting tags with an empty array and setting tagsAreNot " +
+      "should affect query URI"
+  );
+  checkQueryURI([], true);
+});
+
+add_task(async function () {
+  info(
+    "Setting some tags and setting tagsAreNot should result in " +
+      "correct query URI"
+  );
+  checkQueryURI(
+    [
+      "foo",
+      "七難",
+      "",
+      "いっぱいおっぱい",
+      "Abracadabra",
+      "１２３",
+      "Here's a pretty long tag name with some = signs and 1 2 3s and spaces oh jeez will it work I hope so!",
+      "アスキーでございません",
+      "あいうえお",
+    ],
+    true
+  );
+});
+
+add_task(async function tag() {
+  info("Querying on tag associated with a URI should return that URI");
+  await task_doWithBookmark(["foo", "bar", "baz"], function (aURI) {
+    var [query, opts] = makeQuery(["foo"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["bar"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["baz"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+  });
+});
+
+add_task(async function many_tags() {
+  info("Querying on many tags associated with a URI should return that URI");
+  await task_doWithBookmark(["foo", "bar", "baz"], function (aURI) {
+    var [query, opts] = makeQuery(["foo", "bar"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["foo", "baz"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["bar", "baz"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["foo", "bar", "baz"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+  });
+});
+
+add_task(async function repeated_tag() {
+  info("Specifying the same tag multiple times should not matter");
+  await task_doWithBookmark(["foo", "bar", "baz"], function (aURI) {
+    var [query, opts] = makeQuery(["foo", "foo"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["foo", "foo", "foo", "bar", "bar", "baz"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+  });
+});
+
+add_task(async function many_tags_no_bookmark() {
+  info(
+    "Querying on many tags associated with a URI and tags not associated " +
+      "with that URI should not return that URI"
+  );
+  await task_doWithBookmark(["foo", "bar", "baz"], function (aURI) {
+    var [query, opts] = makeQuery(["foo", "bogus"]);
+    executeAndCheckQueryResults(query, opts, []);
+    [query, opts] = makeQuery(["foo", "bar", "bogus"]);
+    executeAndCheckQueryResults(query, opts, []);
+    [query, opts] = makeQuery(["foo", "bar", "baz", "bogus"]);
+    executeAndCheckQueryResults(query, opts, []);
+  });
+});
+
+add_task(async function nonexistent_tags() {
+  info("Querying on nonexistent tag should return no results");
+  await task_doWithBookmark(["foo", "bar", "baz"], function (aURI) {
+    var [query, opts] = makeQuery(["bogus"]);
+    executeAndCheckQueryResults(query, opts, []);
+    [query, opts] = makeQuery(["bogus", "gnarly"]);
+    executeAndCheckQueryResults(query, opts, []);
+  });
+});
+
+add_task(async function tagsAreNot() {
+  info("Querying bookmarks using tagsAreNot should work correctly");
+  var urisAndTags = {
+    "http://example.com/1": ["foo", "bar"],
+    "http://example.com/2": ["baz", "qux"],
+    "http://example.com/3": null,
+  };
+
+  info("Add bookmarks and tag the URIs");
+  for (let [pURI, tags] of Object.entries(urisAndTags)) {
+    let nsiuri = uri(pURI);
+    await addBookmark(nsiuri);
+    if (tags) {
+      PlacesUtils.tagging.tagURI(nsiuri, tags);
+    }
+  }
+
+  info('  Querying for "foo" should match only /2 and /3');
+  var [query, opts] = makeQuery(["foo"], true);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    "http://example.com/2",
+    "http://example.com/3",
+  ]);
+
+  info('  Querying for "foo" and "bar" should match only /2 and /3');
+  [query, opts] = makeQuery(["foo", "bar"], true);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    "http://example.com/2",
+    "http://example.com/3",
+  ]);
+
+  info('  Querying for "foo" and "bogus" should match only /2 and /3');
+  [query, opts] = makeQuery(["foo", "bogus"], true);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    "http://example.com/2",
+    "http://example.com/3",
+  ]);
+
+  info('  Querying for "foo" and "baz" should match only /3');
+  [query, opts] = makeQuery(["foo", "baz"], true);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    "http://example.com/3",
+  ]);
+
+  info('  Querying for "bogus" should match all');
+  [query, opts] = makeQuery(["bogus"], true);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    "http://example.com/1",
+    "http://example.com/2",
+    "http://example.com/3",
+  ]);
+
+  // Clean up.
+  for (let [pURI, tags] of Object.entries(urisAndTags)) {
+    let nsiuri = uri(pURI);
+    if (tags) {
+      PlacesUtils.tagging.untagURI(nsiuri, tags);
+    }
+  }
+  await task_cleanDatabase();
+});
+
+add_task(async function duplicate_tags() {
+  info(
+    "Duplicate existing tags (i.e., multiple tag folders with " +
+      "same name) should not throw off query results"
+  );
+  var tagName = "foo";
+
+  info("Add bookmark and tag it normally");
+  await addBookmark(TEST_URI);
+  PlacesUtils.tagging.tagURI(TEST_URI, [tagName]);
+
+  info("Manually create tag folder with same name as tag and insert bookmark");
+  let dupTag = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: tagName,
+  });
+
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: dupTag.guid,
+    title: "title",
+    url: TEST_URI,
+  });
+
+  info("Querying for tag should match URI");
+  var [query, opts] = makeQuery([tagName]);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    TEST_URI.spec,
+  ]);
+
+  PlacesUtils.tagging.untagURI(TEST_URI, [tagName]);
+  await task_cleanDatabase();
+});
+
+add_task(async function folder_named_as_tag() {
+  info(
+    "Regular folders with the same name as tag should not throw " +
+      "off query results"
+  );
+  var tagName = "foo";
+
+  info("Add bookmark and tag it");
+  await addBookmark(TEST_URI);
+  PlacesUtils.tagging.tagURI(TEST_URI, [tagName]);
+
+  info("Create folder with same name as tag");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: tagName,
+  });
+
+  info("Querying for tag should match URI");
+  var [query, opts] = makeQuery([tagName]);
+  queryResultsAre(PlacesUtils.history.executeQuery(query, opts).root, [
+    TEST_URI.spec,
+  ]);
+
+  PlacesUtils.tagging.untagURI(TEST_URI, [tagName]);
+  await task_cleanDatabase();
+});
+
+add_task(async function ORed_queries() {
+  info("Multiple queries ORed together should work");
+  var urisAndTags = {
+    "http://example.com/1": [],
+    "http://example.com/2": [],
+  };
+
+  // Search with lots of tags to make sure tag parameter substitution in SQL
+  // can handle it with more than one query.
+  for (let i = 0; i < 11; i++) {
+    urisAndTags["http://example.com/1"].push("/1 tag " + i);
+    urisAndTags["http://example.com/2"].push("/2 tag " + i);
+  }
+
+  info("Add bookmarks and tag the URIs");
+  for (let [pURI, tags] of Object.entries(urisAndTags)) {
+    let nsiuri = uri(pURI);
+    await addBookmark(nsiuri);
+    if (tags) {
+      PlacesUtils.tagging.tagURI(nsiuri, tags);
+    }
+  }
+
+  // Clean up.
+  for (let [pURI, tags] of Object.entries(urisAndTags)) {
+    let nsiuri = uri(pURI);
+    if (tags) {
+      PlacesUtils.tagging.untagURI(nsiuri, tags);
+    }
+  }
+  await task_cleanDatabase();
+});
+
+add_task(async function tag_casing() {
+  info(
+    "Querying on associated tags should return " +
+      "correct results irrespective of casing of tags."
+  );
+  await task_doWithBookmark(["fOo", "bAr"], function (aURI) {
+    let [query, opts] = makeQuery(["Foo"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["Foo", "Bar"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["Foo"], true);
+    executeAndCheckQueryResults(query, opts, []);
+    [query, opts] = makeQuery(["Bogus"], true);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+  });
+});
+
+add_task(async function tag_casing_l10n() {
+  info(
+    "Querying on associated tags should return " +
+      "correct results irrespective of casing of tags with international strings."
+  );
+  // \u041F is a lowercase \u043F
+  await task_doWithBookmark(
+    ["\u041F\u0442\u0438\u0446\u044B"],
+    function (aURI) {
+      let [query, opts] = makeQuery(["\u041F\u0442\u0438\u0446\u044B"]);
+      executeAndCheckQueryResults(query, opts, [aURI.spec]);
+      [query, opts] = makeQuery(["\u043F\u0442\u0438\u0446\u044B"]);
+      executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    }
+  );
+  await task_doWithBookmark(
+    ["\u043F\u0442\u0438\u0446\u044B"],
+    function (aURI) {
+      let [query, opts] = makeQuery(["\u041F\u0442\u0438\u0446\u044B"]);
+      executeAndCheckQueryResults(query, opts, [aURI.spec]);
+      [query, opts] = makeQuery(["\u043F\u0442\u0438\u0446\u044B"]);
+      executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    }
+  );
+});
+
+add_task(async function tag_special_char() {
+  info(
+    "Querying on associated tags should return " +
+      "correct results even if tags contain special characters."
+  );
+  await task_doWithBookmark(["Space ☺️ Between"], function (aURI) {
+    let [query, opts] = makeQuery(["Space ☺️ Between"]);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+    [query, opts] = makeQuery(["Space ☺️ Between"], true);
+    executeAndCheckQueryResults(query, opts, []);
+    [query, opts] = makeQuery(["Bogus"], true);
+    executeAndCheckQueryResults(query, opts, [aURI.spec]);
+  });
+});
+
+// The tag keys in query URIs, i.e., "place:tag=foo&!tags=1"
+//                                          ---     -----
+const QUERY_KEY_TAG = "tag";
+const QUERY_KEY_NOT_TAGS = "!tags";
+
+const TEST_URI = uri("http://example.com/");
+
+/**
+ * Adds a bookmark.
+ *
+ * @param aURI
+ *        URI of the page (an nsIURI)
+ */
+function addBookmark(aURI) {
+  return PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: aURI.spec,
+    url: aURI,
+  });
+}
+
+/**
+ * Asynchronous task that removes all pages from history and bookmarks.
+ */
+async function task_cleanDatabase(aCallback) {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+}
+
+/**
+ * Sets up a query with the specified tags, converts it to a URI, and makes sure
+ * the URI is what we expect it to be.
+ *
+ * @param aTags
+ *        The query's tags will be set to those in this array
+ * @param aTagsAreNot
+ *        The query's tagsAreNot property will be set to this
+ */
+function checkQueryURI(aTags, aTagsAreNot) {
+  var pairs = (aTags || []).sort().map(t => QUERY_KEY_TAG + "=" + encodeTag(t));
+  if (aTagsAreNot) {
+    pairs.push(QUERY_KEY_NOT_TAGS + "=1");
+  }
+  var expURI = "place:" + pairs.join("&");
+  var [query, opts] = makeQuery(aTags, aTagsAreNot);
+  var actualURI = queryURI(query, opts);
+  info("Query URI should be what we expect for the given tags");
+  Assert.equal(actualURI, expURI);
+}
+
+/**
+ * Asynchronous task that executes a callback task in a "scoped" database state.
+ * A bookmark is added and tagged before the callback is called, and afterward
+ * the database is cleared.
+ *
+ * @param aTags
+ *        A bookmark will be added and tagged with this array of tags
+ * @param aCallback
+ *        A task function that will be called after the bookmark has been tagged
+ */
+async function task_doWithBookmark(aTags, aCallback) {
+  await addBookmark(TEST_URI);
+  PlacesUtils.tagging.tagURI(TEST_URI, aTags);
+  await aCallback(TEST_URI);
+  PlacesUtils.tagging.untagURI(TEST_URI, aTags);
+  await task_cleanDatabase();
+}
+
+/**
+ * queryToQueryString() encodes every character in the query URI that doesn't
+ * match /[a-zA-Z]/.  There's no simple JavaScript function that does the same,
+ * but encodeURIComponent() comes close, only missing some punctuation.  This
+ * function takes care of all of that.
+ *
+ * @param  aTag
+ *         A tag name to encode
+ * @return A UTF-8 escaped string suitable for inclusion in a query URI
+ */
+function encodeTag(aTag) {
+  return encodeURIComponent(aTag).replace(
+    /[-_.!~*'()]/g, // '
+    s => "%" + s.charCodeAt(0).toString(16)
+  );
+}
+
+/**
+ * Executes the given query and compares the results to the given URIs.
+ * See queryResultsAre().
+ *
+ * @param aQuery
+ *        An nsINavHistoryQuery
+ * @param aQueryOpts
+ *        An nsINavHistoryQueryOptions
+ * @param aExpectedURIs
+ *        Array of URIs (as strings) that aResultRoot should contain
+ */
+function executeAndCheckQueryResults(aQuery, aQueryOpts, aExpectedURIs) {
+  var root = PlacesUtils.history.executeQuery(aQuery, aQueryOpts).root;
+  root.containerOpen = true;
+  queryResultsAre(root, aExpectedURIs);
+  root.containerOpen = false;
+}
+
+/**
+ * Returns new query and query options objects.  The query's tags will be
+ * set to aTags.  aTags may be null, in which case setTags() is not called at
+ * all on the query.
+ *
+ * @param  aTags
+ *         The query's tags will be set to those in this array
+ * @param  aTagsAreNot
+ *         The query's tagsAreNot property will be set to this
+ * @return [query, queryOptions]
+ */
+function makeQuery(aTags, aTagsAreNot) {
+  aTagsAreNot = !!aTagsAreNot;
+  info(
+    "Making a query " +
+      (aTags
+        ? "with tags " + aTags.toSource()
+        : "without calling setTags() at all") +
+      " and with tagsAreNot=" +
+      aTagsAreNot
+  );
+  var query = PlacesUtils.history.getNewQuery();
+  query.tagsAreNot = aTagsAreNot;
+  if (aTags) {
+    query.tags = aTags;
+    var uniqueTags = [];
+    aTags.forEach(function (t) {
+      if (typeof t === "string" && !uniqueTags.includes(t)) {
+        uniqueTags.push(t);
+      }
+    });
+    uniqueTags.sort();
+  }
+
+  info("Made query should be correct for tags and tagsAreNot");
+  if (uniqueTags) {
+    setsAreEqual(query.tags, uniqueTags, true);
+  }
+  var expCount = uniqueTags ? uniqueTags.length : 0;
+  Assert.equal(query.tags.length, expCount);
+  Assert.equal(query.tagsAreNot, aTagsAreNot);
+
+  return [query, PlacesUtils.history.getNewQueryOptions()];
+}
+
+/**
+ * Ensures that the URIs of aResultRoot are the same as those in aExpectedURIs.
+ *
+ * @param aResultRoot
+ *        The nsINavHistoryContainerResultNode root of an nsINavHistoryResult
+ * @param aExpectedURIs
+ *        Array of URIs (as strings) that aResultRoot should contain
+ */
+function queryResultsAre(aResultRoot, aExpectedURIs) {
+  var rootWasOpen = aResultRoot.containerOpen;
+  if (!rootWasOpen) {
+    aResultRoot.containerOpen = true;
+  }
+  var actualURIs = [];
+  for (let i = 0; i < aResultRoot.childCount; i++) {
+    actualURIs.push(aResultRoot.getChild(i).uri);
+  }
+  setsAreEqual(actualURIs, aExpectedURIs);
+  if (!rootWasOpen) {
+    aResultRoot.containerOpen = false;
+  }
+}
+
+/**
+ * Converts the given query into its query URI.
+ *
+ * @param  aQuery
+ *         An nsINavHistoryQuery
+ * @param  aQueryOpts
+ *         An nsINavHistoryQueryOptions
+ * @return The query's URI
+ */
+function queryURI(aQuery, aQueryOpts) {
+  return PlacesUtils.history.queryToQueryString(aQuery, aQueryOpts);
+}
+
+/**
+ * Ensures that the arrays contain the same elements and, optionally, in the
+ * same order.
+ */
+function setsAreEqual(aArr1, aArr2, aIsOrdered) {
+  Assert.equal(aArr1.length, aArr2.length);
+  if (aIsOrdered) {
+    for (let i = 0; i < aArr1.length; i++) {
+      Assert.equal(aArr1[i], aArr2[i]);
+    }
+  } else {
+    aArr1.forEach(u => Assert.ok(aArr2.includes(u)));
+    aArr2.forEach(u => Assert.ok(aArr1.includes(u)));
+  }
+}
diff --git a/toolkit/components/places/tests/queries/test_transitions.js b/toolkit/components/places/tests/queries/test_transitions.js
new file mode 100644
index 0000000000..3055f28e9f
--- /dev/null
+++ b/toolkit/components/places/tests/queries/test_transitions.js
@@ -0,0 +1,175 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* ***** BEGIN LICENSE BLOCK *****
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+ * ***** END LICENSE BLOCK ***** */
+var testData = [
+  {
+    isVisit: true,
+    title: "page 0",
+    uri: "http://mozilla.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_TYPED,
+  },
+  {
+    isVisit: true,
+    title: "page 1",
+    uri: "http://google.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  },
+  {
+    isVisit: true,
+    title: "page 2",
+    uri: "http://microsoft.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  },
+  {
+    isVisit: true,
+    title: "page 3",
+    uri: "http://en.wikipedia.org/",
+    transType: Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+  },
+  {
+    isVisit: true,
+    title: "page 4",
+    uri: "http://fr.wikipedia.org/",
+    transType: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  },
+  {
+    isVisit: true,
+    title: "page 5",
+    uri: "http://apple.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_TYPED,
+  },
+  {
+    isVisit: true,
+    title: "page 6",
+    uri: "http://campus-bike-store.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  },
+  {
+    isVisit: true,
+    title: "page 7",
+    uri: "http://uwaterloo.ca/",
+    transType: Ci.nsINavHistoryService.TRANSITION_TYPED,
+  },
+  {
+    isVisit: true,
+    title: "page 8",
+    uri: "http://pugcleaner.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+  },
+  {
+    isVisit: true,
+    title: "page 9",
+    uri: "http://de.wikipedia.org/",
+    transType: Ci.nsINavHistoryService.TRANSITION_TYPED,
+  },
+  {
+    isVisit: true,
+    title: "arewefastyet",
+    uri: "http://arewefastyet.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+  },
+  {
+    isVisit: true,
+    title: "arewefastyet",
+    uri: "http://arewefastyet.com/",
+    transType: Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+  },
+];
+// sets of indices of testData array by transition type
+var testDataTyped = [0, 5, 7, 9];
+var testDataDownload = [1, 2, 4, 6, 10];
+var testDataBookmark = [3, 8, 11];
+
+add_task(async function test_transitions() {
+  let timeNow = Date.now();
+  for (let item of testData) {
+    await PlacesTestUtils.addVisits({
+      uri: uri(item.uri),
+      transition: item.transType,
+      visitDate: timeNow++ * 1000,
+      title: item.title,
+    });
+  }
+
+  // dump_table("moz_places");
+  // dump_table("moz_historyvisits");
+
+  var numSortFunc = function (a, b) {
+    return a - b;
+  };
+  var arrs = testDataTyped
+    .concat(testDataDownload)
+    .concat(testDataBookmark)
+    .sort(numSortFunc);
+
+  // Four tests which compare the result of a query to an expected set.
+  var data = arrs.filter(function (index) {
+    return (
+      testData[index].uri.match(/arewefastyet\.com/) &&
+      testData[index].transType == Ci.nsINavHistoryService.TRANSITION_DOWNLOAD
+    );
+  });
+
+  compareQueryToTestData(
+    "place:domain=arewefastyet.com&transition=" +
+      Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+    data.slice()
+  );
+
+  compareQueryToTestData(
+    "place:transition=" + Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+    testDataDownload.slice()
+  );
+
+  compareQueryToTestData(
+    "place:transition=" + Ci.nsINavHistoryService.TRANSITION_TYPED,
+    testDataTyped.slice()
+  );
+
+  compareQueryToTestData(
+    "place:transition=" +
+      Ci.nsINavHistoryService.TRANSITION_DOWNLOAD +
+      "&transition=" +
+      Ci.nsINavHistoryService.TRANSITION_BOOKMARK,
+    data
+  );
+
+  // Tests the live update property of transitions.
+  var query = {};
+  var options = {};
+  PlacesUtils.history.queryStringToQuery(
+    "place:transition=" + Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,
+    query,
+    options
+  );
+  var result = PlacesUtils.history.executeQuery(query.value, options.value);
+  var root = result.root;
+  root.containerOpen = true;
+  Assert.equal(testDataDownload.length, root.childCount);
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://getfirefox.com"),
+    transition: TRANSITION_DOWNLOAD,
+  });
+  Assert.equal(testDataDownload.length + 1, root.childCount);
+  root.containerOpen = false;
+});
+
+/*
+ * Takes a query and a set of indices. The indices correspond to elements
+ * of testData that are the result of the query.
+ */
+function compareQueryToTestData(queryStr, data) {
+  var query = {};
+  var options = {};
+  PlacesUtils.history.queryStringToQuery(queryStr, query, options);
+  var result = PlacesUtils.history.executeQuery(query.value, options.value);
+  var root = result.root;
+  for (var i = 0; i < data.length; i++) {
+    data[i] = testData[data[i]];
+    data[i].isInQuery = true;
+  }
+  compareArrayToResult(data, root);
+}
diff --git a/toolkit/components/places/tests/queries/xpcshell.toml b/toolkit/components/places/tests/queries/xpcshell.toml
new file mode 100644
index 0000000000..b171df8c00
--- /dev/null
+++ b/toolkit/components/places/tests/queries/xpcshell.toml
@@ -0,0 +1,57 @@
+[DEFAULT]
+head = "head_queries.js"
+skip-if = ["os == 'android'"]
+
+["test_async.js"]
+
+["test_bookmarks.js"]
+
+["test_containersQueries_sorting.js"]
+
+["test_downloadHistory_liveUpdate.js"]
+
+["test_excludeQueries.js"]
+
+["test_history_queries_tags_liveUpdate.js"]
+
+["test_history_queries_titles_liveUpdate.js"]
+
+["test_options_inherit.js"]
+
+["test_queryMultipleFolder.js"]
+
+["test_querySerialization.js"]
+
+["test_query_uri_liveupdate.js"]
+
+["test_redirects.js"]
+
+["test_result_observeHistoryDetails.js"]
+
+["test_results-as-left-pane.js"]
+
+["test_results-as-roots.js"]
+
+["test_results-as-tag-query.js"]
+
+["test_results-as-visit.js"]
+
+["test_searchTerms_includeHidden.js"]
+
+["test_searchTerms_time.js"]
+
+["test_search_tags.js"]
+
+["test_searchterms-bookmarklets.js"]
+
+["test_searchterms-domain.js"]
+
+["test_searchterms-uri.js"]
+
+["test_sort-date-site-grouping.js"]
+
+["test_sorting.js"]
+
+["test_tags.js"]
+
+["test_transitions.js"]
diff --git a/toolkit/components/places/tests/sync/head_sync.js b/toolkit/components/places/tests/sync/head_sync.js
new file mode 100644
index 0000000000..7dd69e275b
--- /dev/null
+++ b/toolkit/components/places/tests/sync/head_sync.js
@@ -0,0 +1,461 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+
+var { CanonicalJSON } = ChromeUtils.importESModule(
+  "resource://gre/modules/CanonicalJSON.sys.mjs"
+);
+var { Log } = ChromeUtils.importESModule("resource://gre/modules/Log.sys.mjs");
+
+var { PlacesSyncUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesSyncUtils.sys.mjs"
+);
+var { SyncedBookmarksMirror } = ChromeUtils.importESModule(
+  "resource://gre/modules/SyncedBookmarksMirror.sys.mjs"
+);
+var { CommonUtils } = ChromeUtils.importESModule(
+  "resource://services-common/utils.sys.mjs"
+);
+var { FileTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/FileTestUtils.sys.mjs"
+);
+var {
+  HTTP_400,
+  HTTP_401,
+  HTTP_402,
+  HTTP_403,
+  HTTP_404,
+  HTTP_405,
+  HTTP_406,
+  HTTP_407,
+  HTTP_408,
+  HTTP_409,
+  HTTP_410,
+  HTTP_411,
+  HTTP_412,
+  HTTP_413,
+  HTTP_414,
+  HTTP_415,
+  HTTP_417,
+  HTTP_500,
+  HTTP_501,
+  HTTP_502,
+  HTTP_503,
+  HTTP_504,
+  HTTP_505,
+  HttpError,
+  HttpServer,
+} = ChromeUtils.importESModule("resource://testing-common/httpd.sys.mjs");
+
+// These titles are defined in Database::CreateBookmarkRoots
+const BookmarksMenuTitle = "menu";
+const BookmarksToolbarTitle = "toolbar";
+const UnfiledBookmarksTitle = "unfiled";
+const MobileBookmarksTitle = "mobile";
+
+function run_test() {
+  let bufLog = Log.repository.getLogger("Sync.Engine.Bookmarks.Mirror");
+  bufLog.level = Log.Level.All;
+
+  let sqliteLog = Log.repository.getLogger("Sqlite");
+  sqliteLog.level = Log.Level.Error;
+
+  let formatter = new Log.BasicFormatter();
+  let appender = new Log.DumpAppender(formatter);
+  appender.level = Log.Level.All;
+
+  for (let log of [bufLog, sqliteLog]) {
+    log.addAppender(appender);
+  }
+
+  do_get_profile();
+  run_next_test();
+}
+
+// A test helper to insert local roots directly into Places, since the public
+// bookmarks APIs no longer support custom roots.
+async function insertLocalRoot({ guid, title }) {
+  await PlacesUtils.withConnectionWrapper(
+    "insertLocalRoot",
+    async function (db) {
+      let dateAdded = PlacesUtils.toPRTime(new Date());
+      await db.execute(
+        `
+        INSERT INTO moz_bookmarks(guid, type, parent, position, title,
+                                  dateAdded, lastModified)
+        VALUES(:guid, :type, (SELECT id FROM moz_bookmarks
+                              WHERE guid = :parentGuid),
+               (SELECT COUNT(*) FROM moz_bookmarks
+                WHERE parent = (SELECT id FROM moz_bookmarks
+                                WHERE guid = :parentGuid)),
+               :title, :dateAdded, :dateAdded)`,
+        {
+          guid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          parentGuid: PlacesUtils.bookmarks.rootGuid,
+          title,
+          dateAdded,
+        }
+      );
+    }
+  );
+}
+
+// Returns a `CryptoWrapper`-like object that wraps the Sync record cleartext.
+// This exists to avoid importing `record.js` from Sync.
+function makeRecord(cleartext) {
+  return new Proxy(
+    { cleartext },
+    {
+      get(target, property, receiver) {
+        if (property == "cleartext") {
+          return target.cleartext;
+        }
+        if (property == "cleartextToString") {
+          return () => JSON.stringify(target.cleartext);
+        }
+        return target.cleartext[property];
+      },
+      set(target, property, value, receiver) {
+        if (property == "cleartext") {
+          target.cleartext = value;
+        } else if (property != "cleartextToString") {
+          target.cleartext[property] = value;
+        }
+      },
+      has(target, property) {
+        return property == "cleartext" || property in target.cleartext;
+      },
+      deleteProperty(target, property) {},
+      ownKeys(target) {
+        return ["cleartext", ...Reflect.ownKeys(target)];
+      },
+    }
+  );
+}
+
+async function storeRecords(buf, records, options) {
+  await buf.store(records.map(makeRecord), options);
+}
+
+async function storeChangesInMirror(buf, changesToUpload) {
+  let cleartexts = [];
+  for (let recordId in changesToUpload) {
+    changesToUpload[recordId].synced = true;
+    cleartexts.push(changesToUpload[recordId].cleartext);
+  }
+  await storeRecords(buf, cleartexts, { needsMerge: false });
+  await PlacesSyncUtils.bookmarks.pushChanges(changesToUpload);
+}
+
+function inspectChangeRecords(changeRecords) {
+  let results = { updated: [], deleted: [] };
+  for (let [id, record] of Object.entries(changeRecords)) {
+    (record.tombstone ? results.deleted : results.updated).push(id);
+  }
+  results.updated.sort();
+  results.deleted.sort();
+  return results;
+}
+
+async function promiseManyDatesAdded(guids) {
+  let datesAdded = new Map();
+  let db = await PlacesUtils.promiseDBConnection();
+  for (let chunk of PlacesUtils.chunkArray(guids, 100)) {
+    let rows = await db.executeCached(
+      `
+      SELECT guid, dateAdded FROM moz_bookmarks
+      WHERE guid IN (${new Array(chunk.length).fill("?").join(",")})`,
+      chunk
+    );
+    if (rows.length != chunk.length) {
+      throw new TypeError("Can't fetch date added for nonexistent items");
+    }
+    for (let row of rows) {
+      let dateAdded = row.getResultByName("dateAdded") / 1000;
+      datesAdded.set(row.getResultByName("guid"), dateAdded);
+    }
+  }
+  return datesAdded;
+}
+
+async function fetchLocalTree(rootGuid) {
+  function bookmarkNodeToInfo(node) {
+    let { guid, index, title, typeCode: type } = node;
+    let itemInfo = { guid, index, title, type };
+    if (node.annos) {
+      let syncableAnnos = node.annos.filter(anno =>
+        [PlacesUtils.LMANNO_FEEDURI, PlacesUtils.LMANNO_SITEURI].includes(
+          anno.name
+        )
+      );
+      if (syncableAnnos.length) {
+        itemInfo.annos = syncableAnnos;
+      }
+    }
+    if (node.uri) {
+      itemInfo.url = node.uri;
+    }
+    if (node.keyword) {
+      itemInfo.keyword = node.keyword;
+    }
+    if (node.children) {
+      itemInfo.children = node.children.map(bookmarkNodeToInfo);
+    }
+    if (node.tags) {
+      itemInfo.tags = node.tags.split(",").sort();
+    }
+    return itemInfo;
+  }
+  let root = await PlacesUtils.promiseBookmarksTree(rootGuid);
+  return bookmarkNodeToInfo(root);
+}
+
+async function assertLocalTree(rootGuid, expected, message) {
+  let actual = await fetchLocalTree(rootGuid);
+  if (!ObjectUtils.deepEqual(actual, expected)) {
+    info(
+      `Expected structure for ${rootGuid}: ${CanonicalJSON.stringify(expected)}`
+    );
+    info(
+      `Actual structure for ${rootGuid}:   ${CanonicalJSON.stringify(actual)}`
+    );
+    throw new Assert.constructor.AssertionError({ actual, expected, message });
+  }
+}
+
+function makeLivemarkServer() {
+  let server = new HttpServer();
+  server.registerPrefixHandler("/feed/", do_get_file("./livemark.xml"));
+  server.start(-1);
+  return {
+    server,
+    get site() {
+      let { identity } = server;
+      let host = identity.primaryHost.includes(":")
+        ? `[${identity.primaryHost}]`
+        : identity.primaryHost;
+      return `${identity.primaryScheme}://${host}:${identity.primaryPort}`;
+    },
+    stopServer() {
+      return new Promise(resolve => server.stop(resolve));
+    },
+  };
+}
+
+function shuffle(array) {
+  let results = [];
+  for (let i = 0; i < array.length; ++i) {
+    let randomIndex = Math.floor(Math.random() * (i + 1));
+    results[i] = results[randomIndex];
+    results[randomIndex] = array[i];
+  }
+  return results;
+}
+
+async function fetchAllKeywords(info) {
+  let entries = [];
+  await PlacesUtils.keywords.fetch(info, entry => entries.push(entry));
+  return entries;
+}
+
+async function openMirror(name, options = {}) {
+  let buf = await SyncedBookmarksMirror.open({
+    path: `${name}_buf.sqlite`,
+    recordStepTelemetry(...args) {
+      if (options.recordStepTelemetry) {
+        options.recordStepTelemetry.call(this, ...args);
+      }
+    },
+    recordValidationTelemetry(...args) {
+      if (options.recordValidationTelemetry) {
+        options.recordValidationTelemetry.call(this, ...args);
+      }
+    },
+  });
+  return buf;
+}
+
+function BookmarkObserver({ ignoreDates = true, skipTags = false } = {}) {
+  this.notifications = [];
+  this.ignoreDates = ignoreDates;
+  this.skipTags = skipTags;
+  this.handlePlacesEvents = this.handlePlacesEvents.bind(this);
+}
+
+BookmarkObserver.prototype = {
+  handlePlacesEvents(events) {
+    for (let event of events) {
+      switch (event.type) {
+        case "bookmark-added": {
+          if (this.skipTags && event.isTagging) {
+            continue;
+          }
+          let params = {
+            itemId: event.id,
+            parentId: event.parentId,
+            index: event.index,
+            type: event.itemType,
+            urlHref: event.url,
+            title: event.title,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            tags: event.tags,
+            frecency: event.frecency,
+            hidden: event.hidden,
+            visitCount: event.visitCount,
+          };
+          if (!this.ignoreDates) {
+            params.dateAdded = event.dateAdded;
+            params.lastVisitDate = event.lastVisitDate;
+          }
+          this.notifications.push({ name: "bookmark-added", params });
+          break;
+        }
+        case "bookmark-removed": {
+          if (this.skipTags && event.isTagging) {
+            continue;
+          }
+          // Since we are now skipping tags on the listener side we don't
+          // prevent unTagging notifications from going out. These events cause empty
+          // tags folders to be removed which creates another bookmark-removed notification
+          if (
+            this.skipTags &&
+            event.parentGuid == PlacesUtils.bookmarks.tagsGuid
+          ) {
+            continue;
+          }
+          let params = {
+            itemId: event.id,
+            parentId: event.parentId,
+            index: event.index,
+            type: event.itemType,
+            urlHref: event.url || null,
+            title: event.title,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+          };
+          this.notifications.push({ name: "bookmark-removed", params });
+          break;
+        }
+        case "bookmark-moved": {
+          const params = {
+            itemId: event.id,
+            type: event.itemType,
+            urlHref: event.url,
+            source: event.source,
+            guid: event.guid,
+            newIndex: event.index,
+            newParentGuid: event.parentGuid,
+            oldIndex: event.oldIndex,
+            oldParentGuid: event.oldParentGuid,
+            isTagging: event.isTagging,
+            title: event.title,
+            tags: event.tags,
+            frecency: event.frecency,
+            hidden: event.hidden,
+            visitCount: event.visitCount,
+            dateAdded: event.dateAdded,
+            lastVisitDate: event.lastVisitDate,
+          };
+          this.notifications.push({ name: "bookmark-moved", params });
+          break;
+        }
+        case "bookmark-guid-changed": {
+          const params = {
+            itemId: event.id,
+            type: event.itemType,
+            urlHref: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            isTagging: event.isTagging,
+          };
+          this.notifications.push({ name: "bookmark-guid-changed", params });
+          break;
+        }
+        case "bookmark-title-changed": {
+          const params = {
+            itemId: event.id,
+            guid: event.guid,
+            title: event.title,
+            parentGuid: event.parentGuid,
+          };
+          this.notifications.push({ name: "bookmark-title-changed", params });
+          break;
+        }
+        case "bookmark-url-changed": {
+          const params = {
+            itemId: event.id,
+            type: event.itemType,
+            urlHref: event.url,
+            guid: event.guid,
+            parentGuid: event.parentGuid,
+            source: event.source,
+            isTagging: event.isTagging,
+          };
+          this.notifications.push({ name: "bookmark-url-changed", params });
+          break;
+        }
+      }
+    }
+  },
+
+  check(expectedNotifications) {
+    PlacesUtils.observers.removeListener(
+      [
+        "bookmark-added",
+        "bookmark-removed",
+        "bookmark-moved",
+        "bookmark-guid-changed",
+        "bookmark-title-changed",
+        "bookmark-url-changed",
+      ],
+      this.handlePlacesEvents
+    );
+    if (!ObjectUtils.deepEqual(this.notifications, expectedNotifications)) {
+      info(`Expected notifications: ${JSON.stringify(expectedNotifications)}`);
+      info(`Actual notifications: ${JSON.stringify(this.notifications)}`);
+      throw new Assert.constructor.AssertionError({
+        actual: this.notifications,
+        expected: expectedNotifications,
+      });
+    }
+  },
+};
+
+function expectBookmarkChangeNotifications(options) {
+  let observer = new BookmarkObserver(options);
+  PlacesUtils.observers.addListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-guid-changed",
+      "bookmark-title-changed",
+      "bookmark-url-changed",
+    ],
+    observer.handlePlacesEvents
+  );
+  return observer;
+}
+
+// Copies a support file to a temporary fixture file, allowing the support
+// file to be reused for multiple tests.
+async function setupFixtureFile(fixturePath) {
+  let fixtureFile = do_get_file(fixturePath);
+  let tempFile = FileTestUtils.getTempFile(fixturePath);
+  await IOUtils.copy(fixtureFile.path, tempFile.path);
+  return tempFile;
+}
diff --git a/toolkit/components/places/tests/sync/mirror_corrupt.sqlite b/toolkit/components/places/tests/sync/mirror_corrupt.sqlite
new file mode 100644
index 0000000000..ed3613447c
--- /dev/null
+++ b/toolkit/components/places/tests/sync/mirror_corrupt.sqlite
@@ -0,0 +1 @@
+Not a database!
diff --git a/toolkit/components/places/tests/sync/mirror_v1.sqlite b/toolkit/components/places/tests/sync/mirror_v1.sqlite
new file mode 100644
index 0000000000..f0b8853616
--- /dev/null
+++ b/toolkit/components/places/tests/sync/mirror_v1.sqlite
diff --git a/toolkit/components/places/tests/sync/mirror_v5.sqlite b/toolkit/components/places/tests/sync/mirror_v5.sqlite
new file mode 100644
index 0000000000..2a798ae908
--- /dev/null
+++ b/toolkit/components/places/tests/sync/mirror_v5.sqlite
diff --git a/toolkit/components/places/tests/sync/mirror_v8.sqlite b/toolkit/components/places/tests/sync/mirror_v8.sqlite
new file mode 100644
index 0000000000..94d559f08d
--- /dev/null
+++ b/toolkit/components/places/tests/sync/mirror_v8.sqlite
diff --git a/toolkit/components/places/tests/sync/sync_utils_bookmarks.html b/toolkit/components/places/tests/sync/sync_utils_bookmarks.html
new file mode 100644
index 0000000000..53ad366b1f
--- /dev/null
+++ b/toolkit/components/places/tests/sync/sync_utils_bookmarks.html
@@ -0,0 +1,18 @@
+<!DOCTYPE NETSCAPE-Bookmark-file-1>
+<!-- This is an automatically generated file.
+     It will be read and overwritten.
+     DO NOT EDIT! -->
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+<TITLE>Bookmarks</TITLE>
+<H1>Bookmarks Menu</H1>
+
+<DL><p>
+    <DT><A HREF="https://www.mozilla.org/" ADD_DATE="1471365662" LAST_MODIFIED="1471366005" LAST_CHARSET="UTF-8">Mozilla</A>
+    <DD>Mozilla home
+    <DT><H3 ADD_DATE="1449080379" LAST_MODIFIED="1471366005" PERSONAL_TOOLBAR_FOLDER="true">Bookmarks Toolbar</H3>
+    <DD>Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar
+    <DL><p>
+        <DT><A HREF="https://www.mozilla.org/en-US/firefox/" ADD_DATE="1471365681" LAST_MODIFIED="1471366005" SHORTCUTURL="fx" LAST_CHARSET="UTF-8" TAGS="browser">Firefox</A>
+        <DD>Firefox home
+    </DL><p>
+</DL>
diff --git a/toolkit/components/places/tests/sync/sync_utils_bookmarks.json b/toolkit/components/places/tests/sync/sync_utils_bookmarks.json
new file mode 100644
index 0000000000..961140843d
--- /dev/null
+++ b/toolkit/components/places/tests/sync/sync_utils_bookmarks.json
@@ -0,0 +1,94 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1449080379324000,
+  "lastModified": 1471365727344000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1449080379324000,
+      "lastModified": 1471365683893000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "NnvGl3CRA4hC",
+          "title": "Mozilla",
+          "index": 0,
+          "dateAdded": 1471365662585000,
+          "lastModified": 1471365667573000,
+          "id": 6,
+          "charset": "UTF-8",
+          "annos": [
+            {
+              "name": "bookmarkProperties/description",
+              "flags": 0,
+              "expires": 4,
+              "value": "Mozilla home"
+            }
+          ],
+          "type": "text/x-moz-place",
+          "uri": "https://www.mozilla.org/"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1449080379324000,
+      "lastModified": 1471365683893000,
+      "id": 3,
+      "annos": [
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "value": "Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "APzP8MupzA8l",
+          "title": "Firefox",
+          "index": 0,
+          "dateAdded": 1471365681801000,
+          "lastModified": 1471365687887000,
+          "id": 7,
+          "charset": "UTF-8",
+          "tags": "browser",
+          "annos": [
+            {
+              "name": "bookmarkProperties/description",
+              "flags": 0,
+              "expires": 4,
+              "value": "Firefox home"
+            }
+          ],
+          "type": "text/x-moz-place",
+          "uri": "https://www.mozilla.org/en-US/firefox/",
+          "keyword": "fx"
+        }
+      ]
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1449080379324000,
+      "lastModified": 1471365629626000,
+      "id": 5,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder"
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/sync/test_bookmark_abort_merging.js b/toolkit/components/places/tests/sync/test_bookmark_abort_merging.js
new file mode 100644
index 0000000000..877feb99f4
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_abort_merging.js
@@ -0,0 +1,220 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+var { AsyncShutdown } = ChromeUtils.importESModule(
+  "resource://gre/modules/AsyncShutdown.sys.mjs"
+);
+
+add_task(async function test_transaction_in_progress() {
+  let buf = await openMirror("transaction_in_progress");
+
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+  ]);
+
+  // This transaction should block merging until the transaction is committed.
+  info("Open transaction on Places connection");
+  await buf.db.execute("BEGIN EXCLUSIVE");
+
+  await Assert.rejects(
+    buf.apply(),
+    ex => ex.name == "MergeConflictError",
+    "Should not merge when a transaction is in progress"
+  );
+
+  info("Commit open transaction");
+  await buf.db.execute("COMMIT");
+
+  info("Merging should succeed after committing");
+  await buf.apply();
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_abort_store() {
+  let buf = await openMirror("abort_store");
+
+  let controller = new AbortController();
+  controller.abort();
+  await Assert.rejects(
+    storeRecords(
+      buf,
+      [
+        {
+          id: "menu",
+          parentid: "places",
+          type: "folder",
+          children: [],
+        },
+      ],
+      { signal: controller.signal }
+    ),
+    ex => ex.name == "InterruptedError",
+    "Should abort storing when signaled"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_abort_merging() {
+  let buf = await openMirror("abort_merging");
+
+  let controller = new AbortController();
+  controller.abort();
+  await Assert.rejects(
+    buf.apply({ signal: controller.signal }),
+    ex => ex.name == "InterruptedError",
+    "Should abort merge when signaled"
+  );
+
+  // Even though the merger is already finalized on the Rust side, the DB
+  // connection is still open on the JS side. Finalizing `buf` closes it.
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_blocker_state() {
+  let barrier = new AsyncShutdown.Barrier("Test");
+  let buf = await SyncedBookmarksMirror.open({
+    path: "blocker_state_buf.sqlite",
+    finalizeAt: barrier.client,
+    recordStepTelemetry(...args) {},
+    recordValidationTelemetry(...args) {},
+  });
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+  ]);
+
+  await buf.tryApply(buf.finalizeController.signal);
+  await barrier.wait();
+
+  let state = buf.progress.fetchState();
+  let names = [];
+  for (let s of state.steps) {
+    equal(typeof s.at, "number", `Should report timestamp for ${s.step}`);
+    switch (s.step) {
+      case "fetchLocalTree":
+        greaterOrEqual(
+          s.took,
+          0,
+          "Should report time taken to fetch local tree"
+        );
+        deepEqual(
+          s.counts,
+          [
+            { name: "items", count: 6 },
+            { name: "deletions", count: 0 },
+          ],
+          "Should report number of items in local tree"
+        );
+        break;
+
+      case "fetchRemoteTree":
+        greaterOrEqual(
+          s.took,
+          0,
+          "Should report time taken to fetch remote tree"
+        );
+        deepEqual(
+          s.counts,
+          [
+            { name: "items", count: 6 },
+            { name: "deletions", count: 0 },
+          ],
+          "Should report number of items in remote tree"
+        );
+        break;
+
+      case "merge":
+        greaterOrEqual(s.took, 0, "Should report time taken to merge");
+        deepEqual(
+          s.counts,
+          [{ name: "items", count: 6 }],
+          "Should report merge stats"
+        );
+        break;
+
+      case "apply":
+        greaterOrEqual(s.took, 0, "Should report time taken to apply");
+        ok(!("counts" in s), "Should not report counts for applying");
+        break;
+
+      case "notifyObservers":
+        greaterOrEqual(
+          s.took,
+          0,
+          "Should report time taken to notify observers"
+        );
+        ok(!("counts" in s), "Should not report counts for observers");
+        break;
+
+      case "fetchLocalChangeRecords":
+        greaterOrEqual(
+          s.took,
+          0,
+          "Should report time taken to fetch records for upload"
+        );
+        deepEqual(
+          s.counts,
+          [{ name: "items", count: 4 }],
+          "Should report number of records to upload"
+        );
+        break;
+
+      case "finalize":
+        ok(!("took" in s), "Should not report time taken to finalize");
+        ok(!("counts" in s), "Should not report counts for finalizing");
+    }
+    names.push(s.step);
+  }
+  deepEqual(
+    names,
+    [
+      "fetchLocalTree",
+      "fetchRemoteTree",
+      "merge",
+      "apply",
+      "notifyObservers",
+      "fetchLocalChangeRecords",
+      "finalize",
+    ],
+    "Should report merge progress after waiting on blocker"
+  );
+  ok(
+    buf.finalizeController.signal.aborted,
+    "Should abort finalize signal on shutdown"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_chunking.js b/toolkit/components/places/tests/sync/test_bookmark_chunking.js
new file mode 100644
index 0000000000..3652502a3d
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_chunking.js
@@ -0,0 +1,165 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// These tests ensure we correctly chunk statements that exceed SQLite's
+// binding parameter limit.
+
+// Inserts 1500 unfiled bookmarks. Using `PlacesUtils.bookmarks.insertTree`
+// is an order of magnitude slower, so we write bookmarks directly into the
+// database.
+async function insertManyUnfiledBookmarks(db, url) {
+  await db.executeCached(
+    `
+    INSERT OR IGNORE INTO moz_places(id, url, url_hash, rev_host, hidden,
+                                     frecency, guid)
+    VALUES((SELECT id FROM moz_places
+            WHERE url_hash = hash(:url) AND
+                  url = :url), :url, hash(:url), :revHost, 0, -1,
+           generate_guid())`,
+    { url: url.href, revHost: PlacesUtils.getReversedHost(url) }
+  );
+
+  let guids = [];
+
+  for (let position = 0; position < 1500; ++position) {
+    let title = position.toString(10);
+    let guid = title.padStart(12, "A");
+    await db.executeCached(
+      `
+      INSERT INTO moz_bookmarks(guid, parent, fk, position, type, title,
+                                syncStatus, syncChangeCounter)
+      VALUES(:guid, (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+             (SELECT id FROM moz_places WHERE url_hash = hash(:url) AND
+                                              url = :url),
+             :position, :type, :title, :syncStatus, 1)`,
+      {
+        guid,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        position,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title,
+        syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      }
+    );
+    guids.push(guid);
+  }
+
+  return guids;
+}
+
+add_task(async function test_merged_item_chunking() {
+  let buf = await openMirror("merged_item_chunking");
+
+  info("Set up local tree with 1500 bookmarks");
+  let localGuids = await buf.db.executeTransaction(function () {
+    let url = new URL("http://example.com/a");
+    return insertManyUnfiledBookmarks(buf.db, url);
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Set up remote tree with 1500 bookmarks");
+  let toolbarRecord = makeRecord({
+    id: "toolbar",
+    parentid: "places",
+    type: "folder",
+    children: [],
+  });
+  let records = [toolbarRecord];
+  for (let i = 0; i < 1500; ++i) {
+    let title = i.toString(10);
+    let guid = title.padStart(12, "B");
+    toolbarRecord.children.push(guid);
+    records.push(
+      makeRecord({
+        id: guid,
+        parentid: "toolbar",
+        type: "bookmark",
+        title,
+        bmkUri: "http://example.com/b",
+      })
+    );
+  }
+  await buf.store(shuffle(records));
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.unfiledGuid],
+    "Should leave unfiled with new remote structure unmerged"
+  );
+
+  let localChildRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+    "toolbar"
+  );
+  deepEqual(
+    localChildRecordIds,
+    toolbarRecord.children,
+    "Should apply all remote toolbar children"
+  );
+
+  let guidsToUpload = Object.keys(changesToUpload);
+  deepEqual(
+    guidsToUpload.sort(),
+    ["unfiled", ...localGuids].sort(),
+    "Should upload unfiled and all new local children"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_deletion_chunking() {
+  let buf = await openMirror("deletion_chunking");
+
+  info("Set up local tree with 1500 bookmarks");
+  let guids = await buf.db.executeTransaction(function () {
+    let url = new URL("http://example.com/a");
+    return insertManyUnfiledBookmarks(buf.db, url);
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Delete them all on the server");
+  let records = [
+    makeRecord({
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      children: [],
+    }),
+  ];
+  for (let guid of guids) {
+    records.push(
+      makeRecord({
+        id: guid,
+        deleted: true,
+      })
+    );
+  }
+  await buf.store(shuffle(records));
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+  deepEqual(changesToUpload, {}, "Should take all remote deletions");
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Shouldn't store tombstones for remote deletions");
+
+  let localChildRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+    "unfiled"
+  );
+  deepEqual(
+    localChildRecordIds,
+    [],
+    "Should delete all unfiled children locally"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_corruption.js b/toolkit/components/places/tests/sync/test_bookmark_corruption.js
new file mode 100644
index 0000000000..5f0b0afeef
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_corruption.js
@@ -0,0 +1,3290 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+async function reparentItem(db, guid, newParentGuid = null) {
+  await db.execute(
+    `
+     UPDATE moz_bookmarks SET
+       parent = IFNULL((SELECT id FROM moz_bookmarks
+                        WHERE guid = :newParentGuid), 0)
+     WHERE guid = :guid`,
+    { newParentGuid, guid }
+  );
+}
+
+async function getCountOfBookmarkRows(db) {
+  let queryRows = await db.execute("SELECT COUNT(*) FROM moz_bookmarks");
+  Assert.equal(queryRows.length, 1);
+  return queryRows[0].getResultByIndex(0);
+}
+
+add_task(async function test_multiple_parents() {
+  let buf = await openMirror("multiple_parents");
+  let now = Date.now();
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      modified: now / 1000 - 10,
+      children: ["bookmarkAAAA"],
+    },
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      modified: now / 1000 - 5,
+      children: ["bookmarkAAAA", "bookmarkBBBB", "bookmarkCCCC"],
+    },
+    {
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      modified: now / 1000 - 3,
+      children: ["bookmarkBBBB"],
+    },
+    {
+      id: "mobile",
+      parentid: "places",
+      type: "folder",
+      modified: now / 1000,
+      children: ["bookmarkCCCC"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "toolbar",
+      type: "bookmark",
+      title: "A",
+      modified: now / 1000 - 10,
+      bmkUri: "http://example.com/a",
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "mobile",
+      type: "bookmark",
+      title: "B",
+      modified: now / 1000 - 3,
+      bmkUri: "http://example.com/b",
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    localTimeSeconds: now / 1000,
+    remoteTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      "bookmarkAAAA",
+      "bookmarkBBBB",
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.mobileGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave items with new remote structure unmerged"
+  );
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.mobileGuid,
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]);
+  deepEqual(changesToUpload, {
+    menu: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "menu",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+        title: BookmarksMenuTitle,
+        children: ["bookmarkAAAA"],
+      },
+    },
+    toolbar: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "toolbar",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.toolbarGuid),
+        title: BookmarksToolbarTitle,
+        children: [],
+      },
+    },
+    unfiled: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "unfiled",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+        title: UnfiledBookmarksTitle,
+        children: ["bookmarkBBBB"],
+      },
+    },
+    mobile: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "mobile",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.mobileGuid),
+        title: MobileBookmarksTitle,
+        children: [],
+      },
+    },
+    bookmarkAAAA: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkAAAA",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: datesAdded.get("bookmarkAAAA"),
+        bmkUri: "http://example.com/a",
+        title: "A",
+      },
+    },
+    bookmarkBBBB: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkBBBB",
+        type: "bookmark",
+        parentid: "unfiled",
+        hasDupe: true,
+        parentName: UnfiledBookmarksTitle,
+        dateAdded: datesAdded.get("bookmarkBBBB"),
+        bmkUri: "http://example.com/b",
+        title: "B",
+      },
+    },
+  });
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should parent (A B) correctly"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+
+  let newChangesToUpload = await buf.apply({
+    localTimeSeconds: now / 1000,
+    remoteTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    newChangesToUpload,
+    {},
+    "Should not upload any changes after updating mirror"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_reupload_replace() {
+  let buf = await openMirror("reupload_replace");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+      },
+    ],
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "folderBBBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: [],
+      },
+    ],
+    { needsMerge: false }
+  );
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: [
+        "bookmarkAAAA",
+        "folderBBBBBB",
+        "queryCCCCCCC",
+        "queryDDDDDDD",
+      ],
+    },
+    {
+      // A has an invalid URL, but exists locally, so we should reupload a valid
+      // local copy. This discards _all_ remote changes to A.
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A (remote)",
+      bmkUri: "!@#$%",
+    },
+    {
+      id: "folderBBBBBB",
+      parentid: "menu",
+      type: "folder",
+      title: "B (remote)",
+      children: ["bookmarkEEEE"],
+    },
+    {
+      // E is a bookmark with an invalid URL that doesn't exist locally, so we'll
+      // delete it.
+      id: "bookmarkEEEE",
+      parentid: "folderBBBBBB",
+      type: "bookmark",
+      title: "E (remote)",
+      bmkUri: "!@#$%",
+    },
+    {
+      // C is a legacy tag query, so we'll rewrite its URL and reupload it.
+      id: "queryCCCCCCC",
+      parentid: "menu",
+      type: "query",
+      title: "C (remote)",
+      bmkUri: "place:type=7&folder=999",
+      folderName: "taggy",
+    },
+    {
+      // D is a query with an invalid URL, so we'll delete it.
+      id: "queryDDDDDDD",
+      parentid: "menu",
+      type: "query",
+      title: "D",
+      bmkUri: "^&*()",
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      "bookmarkAAAA",
+      "bookmarkEEEE",
+      "folderBBBBBB",
+      PlacesUtils.bookmarks.menuGuid,
+      "queryCCCCCCC",
+      "queryDDDDDDD",
+    ],
+    "Should leave invalid A, E, D; reuploaded C; B, menu with new remote structure unmerged"
+  );
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    "bookmarkAAAA",
+  ]);
+  deepEqual(changesToUpload, {
+    menu: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "menu",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+        title: BookmarksMenuTitle,
+        children: ["bookmarkAAAA", "folderBBBBBB", "queryCCCCCCC"],
+      },
+    },
+    bookmarkAAAA: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkAAAA",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: datesAdded.get("bookmarkAAAA"),
+        bmkUri: "http://example.com/a",
+        title: "A",
+      },
+    },
+    folderBBBBBB: {
+      // B is reuploaded because we deleted its child E.
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "folderBBBBBB",
+        type: "folder",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: undefined,
+        title: "B (remote)",
+        children: [],
+      },
+    },
+    queryCCCCCCC: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "queryCCCCCCC",
+        type: "query",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: undefined,
+        bmkUri: "place:tag=taggy",
+        title: "C (remote)",
+        folderName: "taggy",
+      },
+    },
+    queryDDDDDDD: {
+      tombstone: true,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "queryDDDDDDD",
+        deleted: true,
+      },
+    },
+    bookmarkEEEE: {
+      tombstone: true,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkEEEE",
+        deleted: true,
+      },
+    },
+  });
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["bookmarkEEEE", "queryDDDDDDD"],
+    "Should store local tombstones for (E D)"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_corrupt_local_roots() {
+  let buf = await openMirror("corrupt_roots");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkBBBB"],
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "toolbar",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+  ]);
+
+  try {
+    info("Move local menu into unfiled");
+    await reparentItem(
+      buf.db,
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.unfiledGuid
+    );
+    await Assert.rejects(
+      buf.apply(),
+      /The Places roots are invalid/,
+      "Should abort merge if local tree has misparented syncable root"
+    );
+
+    info("Move local Places root into toolbar");
+    await buf.db.executeTransaction(async function () {
+      await reparentItem(
+        buf.db,
+        PlacesUtils.bookmarks.menuGuid,
+        PlacesUtils.bookmarks.rootGuid
+      );
+      await reparentItem(
+        buf.db,
+        PlacesUtils.bookmarks.rootGuid,
+        PlacesUtils.bookmarks.toolbarGuid
+      );
+    });
+    await Assert.rejects(
+      buf.apply(),
+      /The Places roots are invalid/,
+      "Should abort merge if local tree has misparented Places root"
+    );
+  } finally {
+    info("Restore local roots");
+    await buf.db.executeTransaction(async function () {
+      await reparentItem(buf.db, PlacesUtils.bookmarks.rootGuid);
+      await reparentItem(
+        buf.db,
+        PlacesUtils.bookmarks.menuGuid,
+        PlacesUtils.bookmarks.rootGuid
+      );
+    });
+  }
+
+  info("Apply remote with restored roots");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  deepEqual(changesToUpload, {}, "Should not reupload any local records");
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should parent (A B) correctly with restored roots"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_corrupt_remote_roots() {
+  let buf = await openMirror("corrupt_remote_roots");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes: Menu > Unfiled");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["unfiled", "bookmarkAAAA"],
+    },
+    {
+      id: "unfiled",
+      parentid: "menu",
+      type: "folder",
+      children: ["bookmarkBBBB"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+    {
+      id: "toolbar",
+      deleted: true,
+    },
+  ]);
+
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave deleted roots unmerged"
+  );
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          title: BookmarksMenuTitle,
+          children: ["bookmarkAAAA"],
+        },
+      },
+      unfiled: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "unfiled",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+          title: UnfiledBookmarksTitle,
+          children: ["bookmarkBBBB"],
+        },
+      },
+      toolbar: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "toolbar",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.toolbarGuid),
+          title: BookmarksToolbarTitle,
+          children: [],
+        },
+      },
+    },
+    "Should reupload invalid roots"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should not corrupt local roots"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Should not store local tombstones");
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_missing_children() {
+  let buf = await openMirror("missing_childen");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes: A > ([B] C [D E])");
+  {
+    await storeRecords(
+      buf,
+      shuffle([
+        {
+          id: "menu",
+          parentid: "places",
+          type: "folder",
+          children: [
+            "bookmarkBBBB",
+            "bookmarkCCCC",
+            "bookmarkDDDD",
+            "bookmarkEEEE",
+          ],
+        },
+        {
+          id: "bookmarkCCCC",
+          parentid: "menu",
+          type: "bookmark",
+          bmkUri: "http://example.com/c",
+          title: "C",
+        },
+      ])
+    );
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      [PlacesUtils.bookmarks.menuGuid],
+      "Should leave menu with new remote structure unmerged"
+    );
+
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["menu"],
+        deleted: [],
+      },
+      "Should reupload menu without missing children (B D E)"
+    );
+    await assertLocalTree(
+      PlacesUtils.bookmarks.menuGuid,
+      {
+        guid: PlacesUtils.bookmarks.menuGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        index: 0,
+        title: BookmarksMenuTitle,
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 0,
+            title: "C",
+            url: "http://example.com/c",
+          },
+        ],
+      },
+      "Menu children should be (C)"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  info("Add (B E) to remote");
+  {
+    await storeRecords(
+      buf,
+      shuffle([
+        {
+          id: "bookmarkBBBB",
+          parentid: "menu",
+          type: "bookmark",
+          title: "B",
+          bmkUri: "http://example.com/b",
+        },
+        {
+          id: "bookmarkEEEE",
+          parentid: "menu",
+          type: "bookmark",
+          title: "E",
+          bmkUri: "http://example.com/e",
+        },
+      ])
+    );
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["bookmarkBBBB", "bookmarkEEEE"],
+      "Should leave B, E with new remote structure unmerged"
+    );
+
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["bookmarkBBBB", "bookmarkEEEE", "menu"],
+        deleted: [],
+      },
+      "Should reupload menu and restored children"
+    );
+    await assertLocalTree(
+      PlacesUtils.bookmarks.menuGuid,
+      {
+        guid: PlacesUtils.bookmarks.menuGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        index: 0,
+        title: BookmarksMenuTitle,
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 0,
+            title: "C",
+            url: "http://example.com/c",
+          },
+          {
+            guid: "bookmarkBBBB",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 1,
+            title: "B",
+            url: "http://example.com/b",
+          },
+          {
+            guid: "bookmarkEEEE",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 2,
+            title: "E",
+            url: "http://example.com/e",
+          },
+        ],
+      },
+      "Menu children should be (C B E)"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  info("Add D to remote");
+  {
+    await storeRecords(buf, [
+      {
+        id: "bookmarkDDDD",
+        parentid: "menu",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+    ]);
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["bookmarkDDDD"],
+      "Should leave D with new remote structure unmerged"
+    );
+
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["bookmarkDDDD", "menu"],
+        deleted: [],
+      },
+      "Should reupload complete menu"
+    );
+    await assertLocalTree(
+      PlacesUtils.bookmarks.menuGuid,
+      {
+        guid: PlacesUtils.bookmarks.menuGuid,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        index: 0,
+        title: BookmarksMenuTitle,
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 0,
+            title: "C",
+            url: "http://example.com/c",
+          },
+          {
+            guid: "bookmarkBBBB",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 1,
+            title: "B",
+            url: "http://example.com/b",
+          },
+          {
+            guid: "bookmarkEEEE",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 2,
+            title: "E",
+            url: "http://example.com/e",
+          },
+          {
+            guid: "bookmarkDDDD",
+            type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+            index: 3,
+            title: "D",
+            url: "http://example.com/d",
+          },
+        ],
+      },
+      "Menu children should be (C B E D)"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_new_orphan_without_local_parent() {
+  let buf = await openMirror("new_orphan_without_local_parent");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // A doesn't exist locally, so we move the bookmarks into "unfiled" without
+  // reuploading. When the partial uploader returns and uploads A, we'll
+  // move the bookmarks to the correct folder.
+  info("Make remote changes: [A] > (B C D)");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B (remote)",
+        bmkUri: "http://example.com/b-remote",
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C (remote)",
+        bmkUri: "http://example.com/c-remote",
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "D (remote)",
+        bmkUri: "http://example.com/d-remote",
+      },
+    ])
+  );
+
+  info("Apply remote with (B C D)");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      [
+        "bookmarkBBBB",
+        "bookmarkCCCC",
+        "bookmarkDDDD",
+        PlacesUtils.bookmarks.unfiledGuid,
+      ],
+      "Should leave orphans B, C, D unmerged"
+    );
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["bookmarkBBBB", "bookmarkCCCC", "bookmarkDDDD", "unfiled"],
+        deleted: [],
+      },
+      "Should reupload orphans (B C D)"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.unfiledGuid,
+    {
+      guid: PlacesUtils.bookmarks.unfiledGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 3,
+      title: UnfiledBookmarksTitle,
+      children: [
+        {
+          guid: "bookmarkBBBB",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "B (remote)",
+          url: "http://example.com/b-remote",
+        },
+        {
+          guid: "bookmarkCCCC",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "C (remote)",
+          url: "http://example.com/c-remote",
+        },
+        {
+          guid: "bookmarkDDDD",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "D (remote)",
+          url: "http://example.com/d-remote",
+        },
+      ],
+    },
+    "Should move (B C D) to unfiled"
+  );
+
+  // A is an orphan because we don't have E locally, but we should move
+  // (B C D) into A.
+  info("Add [E] > A to remote");
+  await storeRecords(buf, [
+    {
+      id: "folderAAAAAA",
+      parentid: "folderEEEEEE",
+      type: "folder",
+      title: "A",
+      children: ["bookmarkDDDD", "bookmarkCCCC", "bookmarkBBBB"],
+    },
+  ]);
+
+  info("Apply remote with A");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["folderAAAAAA"],
+      "Should leave A with new remote structure unmerged"
+    );
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: [
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkDDDD",
+          "folderAAAAAA",
+          "unfiled",
+        ],
+        deleted: [],
+      },
+      "Should reupload A and its children"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.unfiledGuid,
+    {
+      guid: PlacesUtils.bookmarks.unfiledGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 3,
+      title: UnfiledBookmarksTitle,
+      children: [
+        {
+          guid: "folderAAAAAA",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "A",
+          children: [
+            {
+              guid: "bookmarkDDDD",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "D (remote)",
+              url: "http://example.com/d-remote",
+            },
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "C (remote)",
+              url: "http://example.com/c-remote",
+            },
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 2,
+              title: "B (remote)",
+              url: "http://example.com/b-remote",
+            },
+          ],
+        },
+      ],
+    },
+    "Should move (D C B) into A"
+  );
+
+  info("Add E to remote");
+  await storeRecords(buf, [
+    {
+      id: "folderEEEEEE",
+      parentid: "menu",
+      type: "folder",
+      title: "E",
+      children: ["folderAAAAAA"],
+    },
+  ]);
+
+  info("Apply remote with E");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["folderEEEEEE"],
+      "Should leave E with new remote structure unmerged"
+    );
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["folderAAAAAA", "folderEEEEEE", "menu", "unfiled"],
+        deleted: [],
+      },
+      "Should move E out of unfiled into menu"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "folderEEEEEE",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "E",
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkDDDD",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "D (remote)",
+                  url: "http://example.com/d-remote",
+                },
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "C (remote)",
+                  url: "http://example.com/c-remote",
+                },
+                {
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 2,
+                  title: "B (remote)",
+                  url: "http://example.com/b-remote",
+                },
+              ],
+            },
+          ],
+        },
+      ],
+    },
+    "Should move Menu > E > A"
+  );
+
+  info("Add Menu > E to remote");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["folderEEEEEE"],
+    },
+  ]);
+
+  info("Apply remote with menu");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: [],
+        deleted: [],
+      },
+      "Should not reupload after forming complete tree"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderEEEEEE",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "E",
+              children: [
+                {
+                  guid: "folderAAAAAA",
+                  type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                  index: 0,
+                  title: "A",
+                  children: [
+                    {
+                      guid: "bookmarkDDDD",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 0,
+                      title: "D (remote)",
+                      url: "http://example.com/d-remote",
+                    },
+                    {
+                      guid: "bookmarkCCCC",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 1,
+                      title: "C (remote)",
+                      url: "http://example.com/c-remote",
+                    },
+                    {
+                      guid: "bookmarkBBBB",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 2,
+                      title: "B (remote)",
+                      url: "http://example.com/b-remote",
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should form complete tree after applying E"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_move_into_orphaned() {
+  let buf = await openMirror("move_into_orphaned");
+
+  info("Set up mirror: Menu > (A B (C > (D (E > F))))");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+      },
+      {
+        guid: "folderCCCCCC",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "C",
+        children: [
+          {
+            guid: "bookmarkDDDD",
+            title: "D",
+            url: "http://example.com/d",
+          },
+          {
+            guid: "folderEEEEEE",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "E",
+            children: [
+              {
+                guid: "bookmarkFFFF",
+                title: "F",
+                url: "http://example.com/f",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkBBBB", "folderCCCCCC"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "menu",
+        type: "folder",
+        title: "C",
+        children: ["bookmarkDDDD", "folderEEEEEE"],
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderCCCCCC",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+      {
+        id: "folderEEEEEE",
+        parentid: "folderCCCCCC",
+        type: "folder",
+        title: "E",
+        children: ["bookmarkFFFF"],
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "folderEEEEEE",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: delete D, add E > I");
+  await PlacesUtils.bookmarks.remove("bookmarkDDDD");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkIIII",
+    parentGuid: "folderEEEEEE",
+    title: "I (local)",
+    url: "http://example.com/i",
+  });
+
+  // G doesn't exist on the server.
+  info("Make remote changes: ([G] > A (C > (D H E))), (C > H)");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkAAAA",
+        parentid: "folderGGGGGG",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "folderGGGGGG",
+        type: "folder",
+        title: "C",
+        children: ["bookmarkDDDD", "bookmarkHHHH", "folderEEEEEE"],
+      },
+      {
+        id: "bookmarkHHHH",
+        parentid: "folderCCCCCC",
+        type: "bookmark",
+        title: "H (remote)",
+        bmkUri: "http://example.com/h-remote",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkAAAA", "folderCCCCCC"],
+    "Should leave orphaned A, C with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [
+        "bookmarkAAAA",
+        "bookmarkIIII",
+        "folderCCCCCC",
+        "folderEEEEEE",
+        "menu",
+      ],
+      deleted: ["bookmarkDDDD"],
+    },
+    "Should upload records for (A I C E); tombstone for D"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              // A remains in its original place, since we don't use the `parentid`,
+              // and we don't have a record for G.
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "B",
+              url: "http://example.com/b",
+            },
+            {
+              // C exists on the server, so we take its children and order. D was
+              // deleted locally, and doesn't exist remotely. C is also a child of
+              // G, but we don't have a record for it on the server.
+              guid: "folderCCCCCC",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 2,
+              title: "C",
+              children: [
+                {
+                  guid: "bookmarkHHHH",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "H (remote)",
+                  url: "http://example.com/h-remote",
+                },
+                {
+                  guid: "folderEEEEEE",
+                  type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                  index: 1,
+                  title: "E",
+                  children: [
+                    {
+                      guid: "bookmarkFFFF",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 0,
+                      title: "F",
+                      url: "http://example.com/f",
+                    },
+                    {
+                      guid: "bookmarkIIII",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 1,
+                      title: "I (local)",
+                      url: "http://example.com/i",
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should treat local tree as canonical if server is missing new parent"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["bookmarkDDDD"],
+    "Should store local tombstone for D"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_new_orphan_with_local_parent() {
+  let buf = await openMirror("new_orphan_with_local_parent");
+
+  info("Set up mirror: A > (B D)");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB", "bookmarkEEEE"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // Simulate a partial write by another device that uploaded only B and C. A
+  // exists locally, so we can move B and C into the correct folder, but not
+  // the correct positions.
+  info("Set up remote with orphans: [A] > (C D)");
+  await storeRecords(buf, [
+    {
+      id: "bookmarkDDDD",
+      parentid: "folderAAAAAA",
+      type: "bookmark",
+      title: "D (remote)",
+      bmkUri: "http://example.com/d-remote",
+    },
+    {
+      id: "bookmarkCCCC",
+      parentid: "folderAAAAAA",
+      type: "bookmark",
+      title: "C (remote)",
+      bmkUri: "http://example.com/c-remote",
+    },
+  ]);
+
+  info("Apply remote with (C D)");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["bookmarkCCCC", "bookmarkDDDD"],
+      "Should leave orphaned C, D unmerged"
+    );
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: ["bookmarkCCCC", "bookmarkDDDD", "folderAAAAAA"],
+        deleted: [],
+      },
+      "Should reupload orphans (C D) and folder A"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "B",
+                  url: "http://example.com/b",
+                },
+                {
+                  guid: "bookmarkEEEE",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "E",
+                  url: "http://example.com/e",
+                },
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 2,
+                  title: "C (remote)",
+                  url: "http://example.com/c-remote",
+                },
+                {
+                  guid: "bookmarkDDDD",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 3,
+                  title: "D (remote)",
+                  url: "http://example.com/d-remote",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should move (C D) to end of A"
+  );
+
+  // The partial uploader returns and uploads A.
+  info("Add A to remote");
+  await storeRecords(buf, [
+    {
+      id: "folderAAAAAA",
+      parentid: "menu",
+      type: "folder",
+      title: "A",
+      children: [
+        "bookmarkCCCC",
+        "bookmarkDDDD",
+        "bookmarkEEEE",
+        "bookmarkBBBB",
+      ],
+    },
+  ]);
+
+  info("Apply remote with A");
+  {
+    let changesToUpload = await buf.apply();
+    deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+    let idsToUpload = inspectChangeRecords(changesToUpload);
+    deepEqual(
+      idsToUpload,
+      {
+        updated: [],
+        deleted: [],
+      },
+      "Should not reupload orphan A"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+  }
+
+  await assertLocalTree(
+    "folderAAAAAA",
+    {
+      guid: "folderAAAAAA",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "A",
+      children: [
+        {
+          guid: "bookmarkCCCC",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "C (remote)",
+          url: "http://example.com/c-remote",
+        },
+        {
+          guid: "bookmarkDDDD",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "D (remote)",
+          url: "http://example.com/d-remote",
+        },
+        {
+          guid: "bookmarkEEEE",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "E",
+          url: "http://example.com/e",
+        },
+        {
+          guid: "bookmarkBBBB",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 3,
+          title: "B",
+          url: "http://example.com/b",
+        },
+      ],
+    },
+    "Should update child positions once A exists in mirror"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_tombstone_as_child() {
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let buf = await openMirror("tombstone_as_child");
+  // Setup the mirror such that an incoming folder references a tombstone
+  // as a child.
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkAAAA", "bookmarkTTTT", "bookmarkBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "Bookmark A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "Bookmark B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkTTTT",
+        deleted: true,
+      },
+    ]),
+    { needsMerge: true }
+  );
+
+  let changesToUpload = await buf.apply();
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(idsToUpload.deleted, [], "no new tombstones were created.");
+  deepEqual(idsToUpload.updated, ["folderAAAAAA"], "parent is re-uploaded");
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkAAAA",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  url: "http://example.com/a",
+                  index: 0,
+                  title: "Bookmark A",
+                },
+                {
+                  // Note that this was the 3rd child specified on the server record,
+                  // but we we've correctly moved it back to being the second after
+                  // ignoring the tombstone.
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  url: "http://example.com/b",
+                  index: 1,
+                  title: "Bookmark B",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should have ignored tombstone record"
+  );
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Should not store local tombstones");
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_non_syncable_items() {
+  let buf = await openMirror("non_syncable_items");
+
+  info("Insert local orphaned left pane queries");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        guid: "folderLEFTPQ",
+        url: "place:folder=SOMETHING",
+        title: "Some query",
+      },
+      {
+        guid: "folderLEFTPC",
+        url: "place:folder=SOMETHING_ELSE",
+        title: "A query under 'All Bookmarks'",
+      },
+    ],
+  });
+
+  info(
+    "Insert syncable local items (A > B) that exist in non-syncable remote root H"
+  );
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // A is non-syncable remotely, but B doesn't exist remotely, so we'll
+        // remove A from the merged structure, and move B to the menu.
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            title: "B",
+            url: "http://example.com/b",
+          },
+        ],
+      },
+    ],
+  });
+
+  info("Insert non-syncable local root C and items (C > (D > E) F)");
+  await insertLocalRoot({
+    guid: "rootCCCCCCCC",
+    title: "C",
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: "rootCCCCCCCC",
+    children: [
+      {
+        guid: "folderDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        children: [
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+          },
+        ],
+      },
+      {
+        guid: "bookmarkFFFF",
+        url: "http://example.com/f",
+        title: "F",
+      },
+    ],
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      // H is a non-syncable root that only exists remotely.
+      id: "rootHHHHHHHH",
+      type: "folder",
+      parentid: "places",
+      title: "H",
+      children: ["folderAAAAAA"],
+    },
+    {
+      // A is a folder with children that's non-syncable remotely, and syncable
+      // locally. We should remove A and its descendants locally, since its parent
+      // H is known to be non-syncable remotely.
+      id: "folderAAAAAA",
+      parentid: "rootHHHHHHHH",
+      type: "folder",
+      title: "A",
+      children: ["bookmarkFFFF", "bookmarkIIII"],
+    },
+    {
+      // F exists in two different non-syncable folders: C locally, and A
+      // remotely.
+      id: "bookmarkFFFF",
+      parentid: "folderAAAAAA",
+      type: "bookmark",
+      title: "F",
+      bmkUri: "http://example.com/f",
+    },
+    {
+      id: "bookmarkIIII",
+      parentid: "folderAAAAAA",
+      type: "query",
+      title: "I",
+      bmkUri: "http://example.com/i",
+    },
+    {
+      // The complete left pane root. We should remove all left pane queries
+      // locally, even though they're syncable, since the left pane root is
+      // known to be non-syncable.
+      id: "folderLEFTPR",
+      type: "folder",
+      parentid: "places",
+      title: "",
+      children: ["folderLEFTPQ", "folderLEFTPF"],
+    },
+    {
+      id: "folderLEFTPQ",
+      parentid: "folderLEFTPR",
+      type: "query",
+      title: "Some query",
+      bmkUri: "place:folder=SOMETHING",
+    },
+    {
+      id: "folderLEFTPF",
+      parentid: "folderLEFTPR",
+      type: "folder",
+      title: "All Bookmarks",
+      children: ["folderLEFTPC"],
+    },
+    {
+      id: "folderLEFTPC",
+      parentid: "folderLEFTPF",
+      type: "query",
+      title: "A query under 'All Bookmarks'",
+      bmkUri: "place:folder=SOMETHING_ELSE",
+    },
+    {
+      // D, J, and G are syncable remotely, but D is non-syncable locally. Since
+      // J and G don't exist locally, and are syncable remotely, we'll remove D
+      // from the merged structure, and move J and G to unfiled.
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      children: ["folderDDDDDD", "bookmarkGGGG"],
+    },
+    {
+      id: "folderDDDDDD",
+      parentid: "unfiled",
+      type: "folder",
+      title: "D",
+      children: ["bookmarkJJJJ"],
+    },
+    {
+      id: "bookmarkJJJJ",
+      parentid: "folderDDDDDD",
+      type: "bookmark",
+      title: "J",
+      bmkUri: "http://example.com/j",
+    },
+    {
+      id: "bookmarkGGGG",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "G",
+      bmkUri: "http://example.com/g",
+    },
+  ]);
+
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      "bookmarkFFFF",
+      "bookmarkIIII",
+      "bookmarkJJJJ",
+      "folderAAAAAA",
+      "folderDDDDDD",
+      "folderLEFTPC",
+      "folderLEFTPF",
+      "folderLEFTPQ",
+      "folderLEFTPR",
+      PlacesUtils.bookmarks.menuGuid,
+      "rootHHHHHHHH",
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave non-syncable items and roots with new remote structure unmerged"
+  );
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    "bookmarkBBBB",
+    "bookmarkJJJJ",
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      folderAAAAAA: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderAAAAAA",
+          deleted: true,
+        },
+      },
+      folderDDDDDD: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderDDDDDD",
+          deleted: true,
+        },
+      },
+      folderLEFTPQ: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderLEFTPQ",
+          deleted: true,
+        },
+      },
+      folderLEFTPC: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderLEFTPC",
+          deleted: true,
+        },
+      },
+      folderLEFTPR: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderLEFTPR",
+          deleted: true,
+        },
+      },
+      folderLEFTPF: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderLEFTPF",
+          deleted: true,
+        },
+      },
+      rootHHHHHHHH: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "rootHHHHHHHH",
+          deleted: true,
+        },
+      },
+      bookmarkFFFF: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkFFFF",
+          deleted: true,
+        },
+      },
+      bookmarkIIII: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkIIII",
+          deleted: true,
+        },
+      },
+      bookmarkBBBB: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkBBBB",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: datesAdded.get("bookmarkBBBB"),
+          bmkUri: "http://example.com/b",
+          title: "B",
+        },
+      },
+      bookmarkJJJJ: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkJJJJ",
+          type: "bookmark",
+          parentid: "unfiled",
+          hasDupe: true,
+          parentName: UnfiledBookmarksTitle,
+          dateAdded: undefined,
+          bmkUri: "http://example.com/j",
+          title: "J",
+        },
+      },
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          title: BookmarksMenuTitle,
+          children: ["bookmarkBBBB"],
+        },
+      },
+      unfiled: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "unfiled",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+          title: UnfiledBookmarksTitle,
+          children: ["bookmarkJJJJ", "bookmarkGGGG"],
+        },
+      },
+    },
+    "Should upload new structure and tombstones for non-syncable items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkJJJJ",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "J",
+              url: "http://example.com/j",
+            },
+            {
+              guid: "bookmarkGGGG",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "G",
+              url: "http://example.com/g",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should exclude non-syncable items from new local structure"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    [
+      "bookmarkFFFF",
+      "bookmarkIIII",
+      "folderAAAAAA",
+      "folderDDDDDD",
+      "folderLEFTPC",
+      "folderLEFTPF",
+      "folderLEFTPQ",
+      "folderLEFTPR",
+      "rootHHHHHHHH",
+    ],
+    "Should store local tombstones for non-syncable items"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// See what happens when a left-pane root and a left-pane query are on the server
+add_task(async function test_left_pane_root() {
+  let buf = await openMirror("lpr");
+
+  let initialTree = await fetchLocalTree(PlacesUtils.bookmarks.rootGuid);
+
+  // This test is expected to not touch bookmarks at all, and if it did
+  // happen to create a new item that's not under our syncable roots, then
+  // just checking the result of fetchLocalTree wouldn't pick that up - so
+  // as an additional safety check, count how many bookmark rows exist.
+  let numRows = await getCountOfBookmarkRows(buf.db);
+
+  // Add a left pane root, a left-pane query and a left-pane folder to the
+  // mirror, all correctly parented.
+  // Because we can determine this is a complete tree that's outside our
+  // syncable trees, we expect none of them to be applied.
+  await storeRecords(
+    buf,
+    shuffle(
+      [
+        {
+          id: "folderLEFTPR",
+          type: "folder",
+          parentid: "places",
+          title: "",
+          children: ["folderLEFTPQ", "folderLEFTPF"],
+        },
+        {
+          id: "folderLEFTPQ",
+          type: "query",
+          parentid: "folderLEFTPR",
+          title: "Some query",
+          bmkUri: "place:folder=SOMETHING",
+        },
+        {
+          id: "folderLEFTPF",
+          type: "folder",
+          parentid: "folderLEFTPR",
+          title: "All Bookmarks",
+          children: ["folderLEFTPC"],
+        },
+        {
+          id: "folderLEFTPC",
+          type: "query",
+          parentid: "folderLEFTPF",
+          title: "A query under 'All Bookmarks'",
+          bmkUri: "place:folder=SOMETHING_ELSE",
+        },
+      ],
+      { needsMerge: true }
+    )
+  );
+
+  await buf.apply();
+
+  // should have ignored everything.
+  await assertLocalTree(PlacesUtils.bookmarks.rootGuid, initialTree);
+
+  // and a check we didn't write *any* items to the places database, even
+  // outside of our user roots.
+  Assert.equal(await getCountOfBookmarkRows(buf.db), numRows);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// See what happens when a left-pane query (without the left-pane root) is on
+// the server
+add_task(async function test_left_pane_query() {
+  let buf = await openMirror("lpq");
+
+  let initialTree = await fetchLocalTree(PlacesUtils.bookmarks.rootGuid);
+
+  // This test is expected to not touch bookmarks at all, and if it did
+  // happen to create a new item that's not under our syncable roots, then
+  // just checking the result of fetchLocalTree wouldn't pick that up - so
+  // as an additional safety check, count how many bookmark rows exist.
+  let numRows = await getCountOfBookmarkRows(buf.db);
+
+  // Add the left pane root and left-pane folders to the mirror, correctly parented.
+  // We should not apply it because we made a policy decision to not apply
+  // orphaned queries (bug 1433182)
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "folderLEFTPQ",
+        type: "query",
+        parentid: "folderLEFTPR",
+        title: "Some query",
+        bmkUri: "place:folder=SOMETHING",
+      },
+    ],
+    { needsMerge: true }
+  );
+
+  await buf.apply();
+
+  // should have ignored everything.
+  await assertLocalTree(PlacesUtils.bookmarks.rootGuid, initialTree);
+
+  // and further check we didn't apply it as mis-rooted.
+  Assert.equal(await getCountOfBookmarkRows(buf.db), numRows);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_partial_cycle() {
+  let buf = await openMirror("partial_cycle");
+
+  info("Set up mirror: Menu > A > B > C");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "folderBBBBBB",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "B",
+            children: [
+              {
+                guid: "bookmarkCCCC",
+                url: "http://example.com/c",
+                title: "C",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["folderBBBBBB"],
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "folderAAAAAA",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // Try to create a cycle: move A into B, and B into the menu, but don't upload
+  // a record for the menu.
+  info("Make remote changes: A > C");
+  await storeRecords(buf, [
+    {
+      id: "folderAAAAAA",
+      parentid: "menu",
+      type: "folder",
+      title: "A (remote)",
+      children: ["bookmarkCCCC"],
+    },
+    {
+      id: "folderBBBBBB",
+      parentid: "folderAAAAAA",
+      type: "folder",
+      title: "B (remote)",
+      children: ["folderAAAAAA"],
+    },
+  ]);
+
+  await Assert.rejects(
+    buf.apply(),
+    /Item <guid: folderBBBBBB> can't contain itself/,
+    "Should abort merge if remote tree parents form `parentid` cycle"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_complete_cycle() {
+  let buf = await openMirror("complete_cycle");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // This test is order-dependent. We shouldn't recurse infinitely, but,
+  // depending on the order of the records, we might ignore the circular
+  // subtree because there's nothing linking it back to the rest of the
+  // tree.
+  info("Make remote changes: Menu > A > B > C > A");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["folderAAAAAA"],
+    },
+    {
+      id: "folderAAAAAA",
+      parentid: "menu",
+      type: "folder",
+      title: "A",
+      children: ["folderBBBBBB"],
+    },
+    {
+      id: "folderBBBBBB",
+      parentid: "folderAAAAAA",
+      type: "folder",
+      title: "B",
+      children: ["folderCCCCCC"],
+    },
+    {
+      id: "folderCCCCCC",
+      parentid: "folderBBBBBB",
+      type: "folder",
+      title: "C",
+      children: ["folderDDDDDD"],
+    },
+    {
+      id: "folderDDDDDD",
+      parentid: "folderCCCCCC",
+      type: "folder",
+      title: "D",
+      children: ["folderAAAAAA"],
+    },
+  ]);
+
+  await Assert.rejects(
+    buf.apply(),
+    /Item <guid: folderAAAAAA> can't contain itself/,
+    "Should abort merge if remote tree parents form cycle through `children`"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_invalid_guid() {
+  let now = new Date();
+
+  let buf = await openMirror("invalid_guid");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA", "bad!guid~", "bookmarkBBBB"],
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+    {
+      id: "bad!guid~",
+      parentid: "menu",
+      type: "bookmark",
+      title: "C",
+      bmkUri: "http://example.com/c",
+      dateAdded: now.getTime(),
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+  ]);
+
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bad!guid~", PlacesUtils.bookmarks.menuGuid],
+    "Should leave bad GUID and menu with new remote structure unmerged"
+  );
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+  ]);
+
+  let recordIdsToUpload = Object.keys(changesToUpload);
+  let newGuid = recordIdsToUpload.find(
+    recordId => !["bad!guid~", "menu"].includes(recordId)
+  );
+
+  equal(
+    recordIdsToUpload.length,
+    3,
+    "Should reupload menu, C, and tombstone for bad GUID"
+  );
+
+  deepEqual(
+    changesToUpload["bad!guid~"],
+    {
+      tombstone: true,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bad!guid~",
+        deleted: true,
+      },
+    },
+    "Should upload tombstone for C's invalid GUID"
+  );
+
+  deepEqual(
+    changesToUpload[newGuid],
+    {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: newGuid,
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: now.getTime(),
+        bmkUri: "http://example.com/c",
+        title: "C",
+      },
+    },
+    "Should reupload C with new GUID"
+  );
+
+  deepEqual(
+    changesToUpload.menu,
+    {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "menu",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+        title: BookmarksMenuTitle,
+        children: ["bookmarkAAAA", newGuid, "bookmarkBBBB"],
+      },
+    },
+    "Should reupload menu with new child GUID for C"
+  );
+
+  await assertLocalTree(PlacesUtils.bookmarks.menuGuid, {
+    guid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    index: 0,
+    title: BookmarksMenuTitle,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        index: 0,
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: newGuid,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        index: 1,
+        title: "C",
+        url: "http://example.com/c",
+      },
+      {
+        guid: "bookmarkBBBB",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        index: 2,
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["bad!guid~"],
+    "Should store local tombstone for C's invalid GUID"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_sync_status_mismatches() {
+  let dateAdded = new Date();
+
+  let buf = await openMirror("sync_status_mismatches");
+
+  info("Ensure mirror is up-to-date with Places");
+  let initialChangesToUpload = await buf.apply();
+
+  deepEqual(
+    Object.keys(initialChangesToUpload).sort(),
+    ["menu", "mobile", "toolbar", "unfiled"],
+    "Should upload roots on first merge"
+  );
+
+  await storeChangesInMirror(buf, initialChangesToUpload);
+
+  info("Make local changes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        // A is NORMAL in Places, but doesn't exist in the mirror.
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+        dateAdded,
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        // B is NEW in Places and exists in the mirror.
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+        dateAdded,
+      },
+    ],
+  });
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkBBBB"],
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkCCCC"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "unfiled",
+        type: "bookmark",
+        bmkUri: "http://example.com/b",
+        title: "B",
+      },
+      {
+        // C is flagged as merged in the mirror, but doesn't exist in Places.
+        id: "bookmarkCCCC",
+        parentid: "toolbar",
+        type: "bookmark",
+        bmkUri: "http://example.com/c",
+        title: "C",
+      },
+    ],
+    { needsMerge: false }
+  );
+
+  info("Apply mirror");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      bookmarkAAAA: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAAA",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: dateAdded.getTime(),
+          bmkUri: "http://example.com/a",
+          title: "A",
+        },
+      },
+      bookmarkBBBB: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkBBBB",
+          type: "bookmark",
+          parentid: "unfiled",
+          hasDupe: true,
+          parentName: UnfiledBookmarksTitle,
+          dateAdded: dateAdded.getTime(),
+          bmkUri: "http://example.com/b",
+          title: "B",
+        },
+      },
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          title: BookmarksMenuTitle,
+          children: ["bookmarkAAAA"],
+        },
+      },
+      unfiled: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "unfiled",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+          title: UnfiledBookmarksTitle,
+          children: ["bookmarkBBBB"],
+        },
+      },
+    },
+    "Should flag (A B) and their parents for upload"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should parent C correctly"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_invalid_local_urls() {
+  let buf = await openMirror("invalid_local_urls");
+
+  info("Skip uploading local roots on first merge");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Set up local tree");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // A has an invalid URL locally and doesn't exist remotely, so we
+        // should delete it without uploading a tombstone.
+        guid: "bookmarkAAAA",
+        title: "A (local)",
+        url: "http://example.com/a",
+      },
+      {
+        // B has an invalid URL locally and has a valid URL remotely, so
+        // we should replace our local copy with the remote one.
+        guid: "bookmarkBBBB",
+        title: "B (local)",
+        url: "http://example.com/b",
+      },
+      {
+        // C has an invalid URL on both sides, so we should delete it locally
+        // and upload a tombstone.
+        guid: "bookmarkCCCC",
+        title: "A (local)",
+        url: "http://example.com/c",
+      },
+    ],
+  });
+
+  // The public API doesn't let us insert invalid URLs (for good reason!), so
+  // we update them directly in Places.
+  info("Invalidate local URLs");
+  await buf.db.executeTransaction(async function () {
+    const invalidURLs = [
+      {
+        guid: "bookmarkAAAA",
+        invalidURL: "!@#$%",
+      },
+      {
+        guid: "bookmarkBBBB",
+        invalidURL: "^&*(",
+      },
+      {
+        guid: "bookmarkCCCC",
+        invalidURL: ")-+!@",
+      },
+    ];
+    for (let params of invalidURLs) {
+      await buf.db.execute(
+        `UPDATE moz_places SET
+           url = :invalidURL,
+           url_hash = hash(:invalidURL)
+         WHERE id = (SELECT fk FROM moz_bookmarks WHERE guid = :guid)`,
+        params
+      );
+    }
+  });
+
+  info("Set up remote tree");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkBBBB", "bookmarkCCCC", "bookmarkDDDD"],
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B (remote)",
+      bmkUri: "http://example.com/b",
+    },
+    {
+      // C should be marked as `VALIDITY_REPLACE` in the mirror database.
+      id: "bookmarkCCCC",
+      parentid: "menu",
+      type: "bookmark",
+      title: "C (remote)",
+      bmkUri: ")(*&^",
+    },
+    {
+      // D has an invalid URL remotely and doesn't exist locally, so we
+      // should replace it with a tombstone.
+      id: "bookmarkDDDD",
+      parentid: "menu",
+      type: "bookmark",
+      title: "D (remote)",
+      bmkUri: "^%$#@",
+    },
+  ]);
+
+  info("Apply mirror");
+  let changesToUpload = await buf.apply();
+
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          title: BookmarksMenuTitle,
+          children: ["bookmarkBBBB"],
+        },
+      },
+      bookmarkCCCC: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkCCCC",
+          deleted: true,
+        },
+      },
+      bookmarkDDDD: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkDDDD",
+          deleted: true,
+        },
+      },
+    },
+    "Should reupload menu and tombstones for (C D)"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkBBBB",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "B (remote)",
+          url: "http://example.com/b",
+        },
+      ],
+    },
+    "Should replace B with remote and delete (A C)"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [],
+    "Should flag all items as merged after upload"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_deduping.js b/toolkit/components/places/tests/sync/test_bookmark_deduping.js
new file mode 100644
index 0000000000..0c6c79496a
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_deduping.js
@@ -0,0 +1,1290 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_duping_local_newer() {
+  let mergeTelemetryCounts;
+  let buf = await openMirror("duping_local_newer", {
+    recordStepTelemetry(name, took, counts) {
+      if (name == "merge") {
+        mergeTelemetryCounts = counts.filter(({ count }) => count > 0);
+      }
+    },
+  });
+  let localModified = new Date();
+
+  info("Start with empty local and mirror with merged items");
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAA5"],
+        dateAdded: localModified.getTime(),
+      },
+      {
+        id: "bookmarkAAA5",
+        parentid: "menu",
+        type: "bookmark",
+        bmkUri: "http://example.com/a",
+        title: "A",
+        dateAdded: localModified.getTime(),
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Add newer local dupes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAA1",
+        title: "A",
+        url: "http://example.com/a",
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+      {
+        guid: "bookmarkAAA2",
+        title: "A",
+        url: "http://example.com/a",
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+      {
+        guid: "bookmarkAAA3",
+        title: "A",
+        url: "http://example.com/a",
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+    ],
+  });
+
+  info("Add older remote dupes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA", "bookmarkAAA4", "bookmarkAAA5"],
+      modified: localModified / 1000 - 5,
+    },
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      bmkUri: "http://example.com/a",
+      title: "A",
+      keyword: "kw",
+      tags: ["remote", "tags"],
+      modified: localModified / 1000 - 5,
+    },
+    {
+      id: "bookmarkAAA4",
+      parentid: "menu",
+      type: "bookmark",
+      bmkUri: "http://example.com/a",
+      title: "A",
+      modified: localModified / 1000 - 5,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    remoteTimeSeconds: localModified / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkAAA4", "bookmarkAAAA", PlacesUtils.bookmarks.menuGuid],
+    "Should leave A4, A, menu with new remote structure unmerged"
+  );
+  deepEqual(
+    mergeTelemetryCounts,
+    [
+      { name: "items", count: 9 },
+      { name: "dupes", count: 2 },
+    ],
+    "Should record telemetry with dupe counts"
+  );
+
+  let menuInfo = await PlacesUtils.bookmarks.fetch(
+    PlacesUtils.bookmarks.menuGuid
+  );
+  deepEqual(
+    changesToUpload,
+    {
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: menuInfo.dateAdded.getTime(),
+          title: menuInfo.title,
+          children: [
+            "bookmarkAAAA",
+            "bookmarkAAA4",
+            "bookmarkAAA3",
+            "bookmarkAAA5",
+          ],
+        },
+      },
+      // Note that we always reupload the deduped local item, because content
+      // matching doesn't account for attributes like keywords, synced annos, or
+      // tags.
+      bookmarkAAAA: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAAA",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: localModified.getTime(),
+          title: "A",
+          bmkUri: "http://example.com/a",
+        },
+      },
+      // Unchanged from local.
+      bookmarkAAA4: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAA4",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: localModified.getTime(),
+          title: "A",
+          bmkUri: "http://example.com/a",
+        },
+      },
+      bookmarkAAA3: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAA3",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: localModified.getTime(),
+          title: "A",
+          bmkUri: "http://example.com/a",
+        },
+      },
+      bookmarkAAA5: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAA5",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: localModified.getTime(),
+          title: "A",
+          bmkUri: "http://example.com/a",
+        },
+      },
+    },
+    "Should uploaded newer deduped local items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A",
+          url: "http://example.com/a",
+        },
+        {
+          guid: "bookmarkAAA4",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "A",
+          url: "http://example.com/a",
+        },
+        {
+          guid: "bookmarkAAA3",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "A",
+          url: "http://example.com/a",
+        },
+        {
+          guid: "bookmarkAAA5",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 3,
+          title: "A",
+          url: "http://example.com/a",
+        },
+      ],
+    },
+    "Should dedupe local multiple bookmarks with similar contents"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_duping_remote_newer() {
+  let buf = await openMirror("duping_remote_new");
+  let localModified = new Date();
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // Shouldn't dupe to `folderA11111` because its sync status is "NORMAL".
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            // Shouldn't dupe to `bookmarkG111`.
+            guid: "bookmarkGGGG",
+            url: "http://example.com/g",
+            title: "G",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkGGGG"],
+      },
+      {
+        id: "bookmarkGGGG",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Insert local dupes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // Should dupe to `folderB11111`.
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+        dateAdded: localModified,
+        lastModified: localModified,
+        children: [
+          {
+            // Should dupe to `bookmarkC222`.
+            guid: "bookmarkC111",
+            url: "http://example.com/c",
+            title: "C",
+            dateAdded: localModified,
+            lastModified: localModified,
+          },
+          {
+            // Should dupe to `separatorF11` because the positions are the same.
+            guid: "separatorFFF",
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+            dateAdded: localModified,
+            lastModified: localModified,
+          },
+        ],
+      },
+      {
+        // Shouldn't dupe to `separatorE11`, because the positions are different.
+        guid: "separatorEEE",
+        type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+      {
+        // Shouldn't dupe to `bookmarkC222` because the parents are different.
+        guid: "bookmarkCCCC",
+        url: "http://example.com/c",
+        title: "C",
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+      {
+        // Should dupe to `queryD111111`.
+        guid: "queryDDDDDDD",
+        url: "place:maxResults=10&sort=8",
+        title: "Most Visited",
+        dateAdded: localModified,
+        lastModified: localModified,
+      },
+    ],
+  });
+
+  // Make sure we still dedupe this even though it doesn't have SYNC_STATUS.NEW
+  PlacesTestUtils.setBookmarkSyncFields({
+    guid: "folderBBBBBB",
+    syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN,
+  });
+
+  // Not a candidate for `bookmarkH111` because we didn't dupe `folderAAAAAA`.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: "folderAAAAAA",
+    guid: "bookmarkHHHH",
+    url: "http://example.com/h",
+    title: "H",
+    dateAdded: localModified,
+    lastModified: localModified,
+  });
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "folderAAAAAA",
+          "folderB11111",
+          "folderA11111",
+          "separatorE11",
+          "queryD111111",
+        ],
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "folderB11111",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkC222", "separatorF11"],
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "bookmarkC222",
+        parentid: "folderB11111",
+        type: "bookmark",
+        bmkUri: "http://example.com/c",
+        title: "C",
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "separatorF11",
+        parentid: "folderB11111",
+        type: "separator",
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "folderA11111",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkG111"],
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "bookmarkG111",
+        parentid: "folderA11111",
+        type: "bookmark",
+        bmkUri: "http://example.com/g",
+        title: "G",
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "separatorE11",
+        parentid: "menu",
+        type: "separator",
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+      {
+        id: "queryD111111",
+        parentid: "menu",
+        type: "query",
+        bmkUri: "place:maxResults=10&sort=8",
+        title: "Most Visited",
+        dateAdded: localModified.getTime(),
+        modified: localModified / 1000 + 5,
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    remoteTimeSeconds: localModified / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid],
+    "Should leave menu with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [
+        "bookmarkCCCC",
+        "bookmarkHHHH",
+        "folderAAAAAA",
+        "menu",
+        "separatorEEE",
+      ],
+      deleted: [],
+    },
+    "Should not upload deduped local records"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkGGGG",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "G",
+                  url: "http://example.com/g",
+                },
+                {
+                  guid: "bookmarkHHHH",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "H",
+                  url: "http://example.com/h",
+                },
+              ],
+            },
+            {
+              guid: "folderB11111",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 1,
+              title: "B",
+              children: [
+                {
+                  guid: "bookmarkC222",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "C",
+                  url: "http://example.com/c",
+                },
+                {
+                  guid: "separatorF11",
+                  type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+                  index: 1,
+                  title: "",
+                },
+              ],
+            },
+            {
+              guid: "folderA11111",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 2,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkG111",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "G",
+                  url: "http://example.com/g",
+                },
+              ],
+            },
+            {
+              guid: "separatorE11",
+              type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+              index: 3,
+              title: "",
+            },
+            {
+              guid: "queryD111111",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 4,
+              title: "Most Visited",
+              url: "place:maxResults=10&sort=8",
+            },
+            {
+              guid: "separatorEEE",
+              type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+              index: 5,
+              title: "",
+            },
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 6,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should dedupe matching NEW bookmarks"
+  );
+
+  ok(
+    (
+      await PlacesTestUtils.fetchBookmarkSyncFields(
+        "menu________",
+        "folderB11111",
+        "bookmarkC222",
+        "separatorF11",
+        "folderA11111",
+        "bookmarkG111",
+        "separatorE11",
+        "queryD111111"
+      )
+    ).every(info => info.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL)
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_duping_both() {
+  let buf = await openMirror("duping_both");
+  let now = Date.now();
+
+  info("Start with empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Add local dupes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // `folderAAAAA1` is older than `folderAAAAAA`, but we should still flag
+        // it for upload because it has a new structure (`bookmarkCCCC`).
+        guid: "folderAAAAA1",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        dateAdded: new Date(now - 10000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            // Shouldn't upload, since `bookmarkBBBB` is newer.
+            guid: "bookmarkBBB1",
+            title: "B",
+            url: "http://example.com/b",
+            dateAdded: new Date(now - 10000),
+            lastModified: new Date(now - 5000),
+          },
+          {
+            // Should upload, since `bookmarkCCCC` doesn't exist on the server and
+            // has no content matches.
+            guid: "bookmarkCCCC",
+            title: "C",
+            url: "http://example.com/c",
+            dateAdded: new Date(now - 10000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        // `folderDDDDD1` should keep complete local structure, but we'll still
+        // flag it for reupload because it's newer than `folderDDDDDD`.
+        guid: "folderDDDDD1",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        dateAdded: new Date(now - 10000),
+        lastModified: new Date(now + 5000),
+        children: [
+          {
+            guid: "bookmarkEEE1",
+            title: "E",
+            url: "http://example.com/e",
+            dateAdded: new Date(now - 10000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        // `folderFFFFF1` should keep complete remote value and structure, so
+        // we shouldn't upload it or its children.
+        guid: "folderFFFFF1",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "F",
+        dateAdded: new Date(now - 10000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            guid: "bookmarkGGG1",
+            title: "G",
+            url: "http://example.com/g",
+            dateAdded: new Date(now - 10000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+    ],
+  });
+
+  info("Add remote dupes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["folderAAAAAA", "folderDDDDDD", "folderFFFFFF"],
+    },
+    {
+      id: "folderAAAAAA",
+      parentid: "menu",
+      type: "folder",
+      title: "A",
+      dateAdded: now - 10000,
+      modified: now / 1000 + 5,
+      children: ["bookmarkBBBB"],
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "folderAAAAAA",
+      type: "bookmark",
+      bmkUri: "http://example.com/b",
+      title: "B",
+      dateAdded: now - 10000,
+      modified: now / 1000 + 5,
+    },
+    {
+      id: "folderDDDDDD",
+      parentid: "menu",
+      type: "folder",
+      title: "D",
+      dateAdded: now - 10000,
+      modified: now / 1000 - 5,
+      children: ["bookmarkEEEE"],
+    },
+    {
+      id: "bookmarkEEEE",
+      parentid: "folderDDDDDD",
+      type: "bookmark",
+      bmkUri: "http://example.com/e",
+      title: "E",
+      dateAdded: now - 10000,
+      modified: now / 1000 + 5,
+    },
+    {
+      id: "folderFFFFFF",
+      parentid: "menu",
+      type: "folder",
+      title: "F",
+      dateAdded: now - 10000,
+      modified: now / 1000 + 5,
+      children: ["bookmarkGGGG", "bookmarkHHHH"],
+    },
+    {
+      id: "bookmarkGGGG",
+      parentid: "folderFFFFFF",
+      type: "bookmark",
+      bmkUri: "http://example.com/g",
+      title: "G",
+      dateAdded: now - 10000,
+      modified: now / 1000 - 5,
+    },
+    {
+      id: "bookmarkHHHH",
+      parentid: "folderFFFFFF",
+      type: "bookmark",
+      bmkUri: "http://example.com/h",
+      title: "H",
+      dateAdded: now - 10000,
+      modified: now / 1000 + 5,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    remoteTimeSeconds: now / 1000,
+  });
+
+  let menuInfo = await PlacesUtils.bookmarks.fetch(
+    PlacesUtils.bookmarks.menuGuid
+  );
+  deepEqual(
+    changesToUpload,
+    {
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: menuInfo.dateAdded.getTime(),
+          title: menuInfo.title,
+          children: ["folderAAAAAA", "folderDDDDDD", "folderFFFFFF"],
+        },
+      },
+      folderAAAAAA: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderAAAAAA",
+          type: "folder",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: now - 10000,
+          title: "A",
+          children: ["bookmarkBBBB", "bookmarkCCCC"],
+        },
+      },
+      bookmarkCCCC: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkCCCC",
+          type: "bookmark",
+          parentid: "folderAAAAAA",
+          hasDupe: true,
+          parentName: "A",
+          dateAdded: now - 10000,
+          title: "C",
+          bmkUri: "http://example.com/c",
+        },
+      },
+      folderDDDDDD: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderDDDDDD",
+          type: "folder",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: menuInfo.title,
+          dateAdded: now - 10000,
+          title: "D",
+          children: ["bookmarkEEEE"],
+        },
+      },
+    },
+    "Should upload new and newer locally deduped items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "folderAAAAAA",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "A",
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: "folderDDDDDD",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: "D",
+          children: [
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "E",
+              url: "http://example.com/e",
+            },
+          ],
+        },
+        {
+          guid: "folderFFFFFF",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 2,
+          title: "F",
+          children: [
+            {
+              guid: "bookmarkGGGG",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "G",
+              url: "http://example.com/g",
+            },
+            {
+              guid: "bookmarkHHHH",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "H",
+              url: "http://example.com/h",
+            },
+          ],
+        },
+      ],
+    },
+    "Should change local GUIDs for mixed older and newer items"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_applying_two_empty_folders_doesnt_smush() {
+  let buf = await openMirror("applying_two_empty_folders_doesnt_smush");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: ["emptyempty01", "emptyempty02"],
+      },
+      {
+        id: "emptyempty01",
+        parentid: "mobile",
+        type: "folder",
+        title: "Empty",
+      },
+      {
+        id: "emptyempty02",
+        parentid: "mobile",
+        type: "folder",
+        title: "Empty",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [],
+      deleted: [],
+    },
+    "Should not upload records for remote-only value changes"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.mobileGuid,
+    {
+      guid: PlacesUtils.bookmarks.mobileGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 4,
+      title: "mobile",
+      children: [
+        {
+          guid: "emptyempty01",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "Empty",
+        },
+        {
+          guid: "emptyempty02",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: "Empty",
+        },
+      ],
+    },
+    "Should not smush 1 and 2"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_applying_two_empty_folders_matches_only_one() {
+  let buf = await openMirror("applying_two_empty_folders_doesnt_smush");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.mobileGuid,
+    children: [
+      {
+        guid: "emptyempty02",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Empty",
+      },
+      {
+        guid: "emptyemptyL0",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Empty",
+      },
+    ],
+  });
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: ["emptyempty01", "emptyempty02", "emptyempty03"],
+      },
+      {
+        id: "emptyempty01",
+        parentid: "mobile",
+        type: "folder",
+        title: "Empty",
+      },
+      {
+        id: "emptyempty02",
+        parentid: "mobile",
+        type: "folder",
+        title: "Empty",
+      },
+      {
+        id: "emptyempty03",
+        parentid: "mobile",
+        type: "folder",
+        title: "Empty",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.mobileGuid],
+    "Should leave mobile with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["mobile"],
+      deleted: [],
+    },
+    "Should not upload records after applying empty folders"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.mobileGuid,
+    {
+      guid: PlacesUtils.bookmarks.mobileGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 4,
+      title: "mobile",
+      children: [
+        {
+          guid: "emptyempty01",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "Empty",
+        },
+        {
+          guid: "emptyempty02",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: "Empty",
+        },
+        {
+          guid: "emptyempty03",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 2,
+          title: "Empty",
+        },
+      ],
+    },
+    "Should apply 1 and dedupe L0 to 3"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// Bug 747699.
+add_task(async function test_duping_mobile_bookmarks() {
+  let buf = await openMirror("duping_mobile_bookmarks");
+
+  info("Set up empty mirror with localized mobile root title");
+  let mobileInfo = await PlacesUtils.bookmarks.fetch(
+    PlacesUtils.bookmarks.mobileGuid
+  );
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.mobileGuid,
+    title: "Favoritos do celular",
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkAAA1",
+    parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    title: "A",
+    url: "http://example.com/a",
+  });
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "mobile",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.mobileGuid],
+    "Should leave mobile with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["mobile"],
+      deleted: [],
+    },
+    "Should not upload records after applying deduped mobile bookmark"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.mobileGuid,
+    {
+      guid: PlacesUtils.bookmarks.mobileGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 4,
+      title: "Favoritos do celular",
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A",
+          url: "http://example.com/a",
+        },
+      ],
+    },
+    "Should dedupe A1 to A with different parent title"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  // Restore the original mobile root title.
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.mobileGuid,
+    title: mobileInfo.title,
+  });
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_duping_invalid() {
+  // To check if invalid items are prevented from deduping
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAA1",
+        title: "A",
+        url: "http://example.com/a",
+      },
+    ],
+  });
+
+  let buf = await openMirror("duping_invalid");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAA2"],
+    },
+    {
+      id: "bookmarkAAA2",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A",
+      bmkUri: "http://example.com/a",
+    },
+  ]);
+
+  // Invalidate bookmarkAAA2 so that it does not dedupe to bookmarkAAA1
+  await buf.db.execute(
+    `UPDATE items SET
+       validity = :validity
+     WHERE guid = :guid`,
+    {
+      validity: Ci.mozISyncedBookmarksMerger.VALIDITY_REPLACE,
+      guid: "bookmarkAAA2",
+    }
+  );
+
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    changesToUpload.menu.cleartext.children,
+    ["bookmarkAAA1"],
+    "Should upload A1 in menu"
+  );
+  ok(
+    !changesToUpload.bookmarkAAA1.tombstone,
+    "Should not upload tombstone for A1"
+  );
+  ok(changesToUpload.bookmarkAAA2.tombstone, "Should upload tombstone for A2");
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAA1",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A",
+          url: "http://example.com/a",
+        },
+      ],
+    },
+    "No deduping of invalid items"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_deletion.js b/toolkit/components/places/tests/sync/test_bookmark_deletion.js
new file mode 100644
index 0000000000..fd29252e74
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_deletion.js
@@ -0,0 +1,1602 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_complex_orphaning() {
+  let now = Date.now();
+
+  let mergeTelemetryCounts;
+  let buf = await openMirror("complex_orphaning", {
+    recordStepTelemetry(name, took, counts) {
+      if (name == "merge") {
+        mergeTelemetryCounts = counts.filter(({ count }) => count > 0);
+      }
+    },
+  });
+
+  // On iOS, the mirror exists as a separate table. On Desktop, we have a
+  // shadow mirror of synced local bookmarks without new changes.
+  info("Set up mirror: ((Toolbar > A > B) (Menu > G > C > D))");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "folderBBBBBB",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "B",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "toolbar",
+        type: "folder",
+        title: "A",
+        children: ["folderBBBBBB"],
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "folderAAAAAA",
+        type: "folder",
+        title: "B",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderGGGGGG",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "G",
+        children: [
+          {
+            guid: "folderCCCCCC",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "C",
+            children: [
+              {
+                guid: "folderDDDDDD",
+                type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                title: "D",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderGGGGGG"],
+      },
+      {
+        id: "folderGGGGGG",
+        parentid: "menu",
+        type: "folder",
+        title: "G",
+        children: ["folderCCCCCC"],
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "folderGGGGGG",
+        type: "folder",
+        title: "C",
+        children: ["folderDDDDDD"],
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "folderCCCCCC",
+        type: "folder",
+        title: "D",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: delete D, add B > E");
+  await PlacesUtils.bookmarks.remove("folderDDDDDD");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkEEEE",
+    parentGuid: "folderBBBBBB",
+    title: "E",
+    url: "http://example.com/e",
+  });
+
+  info("Make remote changes: delete B, add D > F");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "folderBBBBBB",
+        deleted: true,
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "toolbar",
+        type: "folder",
+        title: "A",
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "folderCCCCCC",
+        type: "folder",
+        children: ["bookmarkFFFF"],
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkFFFF", "folderAAAAAA", "folderDDDDDD"],
+    "Should leave deleted D; A and F with new remote structure unmerged"
+  );
+  deepEqual(
+    mergeTelemetryCounts,
+    [
+      { name: "items", count: 10 },
+      { name: "localDeletes", count: 1 },
+      { name: "remoteDeletes", count: 1 },
+    ],
+    "Should record telemetry with structure change counts"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkEEEE", "bookmarkFFFF", "folderAAAAAA", "folderCCCCCC"],
+      deleted: ["folderDDDDDD"],
+    },
+    "Should upload new records for (A > E), (C > F); tombstone for D"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderGGGGGG",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "G",
+              children: [
+                {
+                  guid: "folderCCCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                  index: 0,
+                  title: "C",
+                  children: [
+                    {
+                      // D was deleted, so F moved to C, the closest surviving parent.
+                      guid: "bookmarkFFFF",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 0,
+                      title: "F",
+                      url: "http://example.com/f",
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  // B was deleted, so E moved to A.
+                  guid: "bookmarkEEEE",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "E",
+                  url: "http://example.com/e",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should move orphans to closest surviving parent"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["folderDDDDDD"],
+    "Should store local tombstone for D"
+  );
+  Assert.ok(
+    is_time_ordered(now, tombstones[0].dateRemoved.getTime()),
+    "Tombstone timestamp should be recent"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_locally_modified_remotely_deleted() {
+  let mergeTelemetryCounts;
+  let buf = await openMirror("locally_modified_remotely_deleted", {
+    recordStepTelemetry(name, took, counts) {
+      if (name == "merge") {
+        mergeTelemetryCounts = counts.filter(({ count }) => count > 0);
+      }
+    },
+  });
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            title: "C",
+            url: "http://example.com/c",
+          },
+          {
+            guid: "folderDDDDDD",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "D",
+            children: [
+              {
+                guid: "bookmarkEEEE",
+                title: "E",
+                url: "http://example.com/e",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "folderBBBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC", "folderDDDDDD"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "folderBBBBBB",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkEEEE"],
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: change A; B > ((D > F) G)");
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkAAAA",
+    title: "A (local)",
+    url: "http://example.com/a-local",
+  });
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkFFFF",
+    parentGuid: "folderDDDDDD",
+    title: "F (local)",
+    url: "http://example.com/f-local",
+  });
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkGGGG",
+    parentGuid: "folderBBBBBB",
+    title: "G (local)",
+    url: "http://example.com/g-local",
+  });
+
+  info("Make remote changes: delete A, B");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: [],
+    },
+    {
+      id: "bookmarkAAAA",
+      deleted: true,
+    },
+    {
+      id: "folderBBBBBB",
+      deleted: true,
+    },
+    {
+      id: "bookmarkCCCC",
+      deleted: true,
+    },
+    {
+      id: "folderDDDDDD",
+      deleted: true,
+    },
+    {
+      id: "bookmarkEEEE",
+      deleted: true,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkAAAA", PlacesUtils.bookmarks.menuGuid],
+    "Should leave revived A and menu with new remote structure unmerged"
+  );
+  deepEqual(
+    mergeTelemetryCounts,
+    [
+      { name: "items", count: 8 },
+      { name: "localRevives", count: 1 },
+      { name: "remoteDeletes", count: 2 },
+    ],
+    "Should record telemetry for local item and remote folder deletions"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkAAAA", "bookmarkFFFF", "bookmarkGGGG", "menu"],
+      deleted: [],
+    },
+    "Should upload A, relocated local orphans, and menu"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A (local)",
+          url: "http://example.com/a-local",
+        },
+        {
+          guid: "bookmarkFFFF",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "F (local)",
+          url: "http://example.com/f-local",
+        },
+        {
+          guid: "bookmarkGGGG",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "G (local)",
+          url: "http://example.com/g-local",
+        },
+      ],
+    },
+    "Should restore A and relocate (F G) to menu"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Should not store local tombstones");
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_locally_deleted_remotely_modified() {
+  let now = Date.now();
+
+  let mergeTelemetryCounts;
+  let buf = await openMirror("locally_deleted_remotely_modified", {
+    recordStepTelemetry(name, took, counts) {
+      if (name == "merge") {
+        mergeTelemetryCounts = counts.filter(({ count }) => count > 0);
+      }
+    },
+  });
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            title: "C",
+            url: "http://example.com/c",
+          },
+          {
+            guid: "folderDDDDDD",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "D",
+            children: [
+              {
+                guid: "bookmarkEEEE",
+                title: "E",
+                url: "http://example.com/e",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "folderBBBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC", "folderDDDDDD"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "folderBBBBBB",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkEEEE"],
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: delete A, B");
+  await PlacesUtils.bookmarks.remove("bookmarkAAAA");
+  await PlacesUtils.bookmarks.remove("folderBBBBBB");
+
+  info("Make remote changes: change A; B > ((D > F) G)");
+  await storeRecords(buf, [
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A (remote)",
+      bmkUri: "http://example.com/a-remote",
+    },
+    {
+      id: "folderBBBBBB",
+      parentid: "menu",
+      type: "folder",
+      title: "B (remote)",
+      children: ["bookmarkCCCC", "folderDDDDDD", "bookmarkGGGG"],
+    },
+    {
+      id: "folderDDDDDD",
+      parentid: "folderBBBBBB",
+      type: "folder",
+      title: "D",
+      children: ["bookmarkEEEE", "bookmarkFFFF"],
+    },
+    {
+      id: "bookmarkFFFF",
+      parentid: "folderDDDDDD",
+      type: "bookmark",
+      title: "F (remote)",
+      bmkUri: "http://example.com/f-remote",
+    },
+    {
+      id: "bookmarkGGGG",
+      parentid: "folderBBBBBB",
+      type: "bookmark",
+      title: "G (remote)",
+      bmkUri: "http://example.com/g-remote",
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkFFFF", "bookmarkGGGG", "folderBBBBBB", "folderDDDDDD"],
+    "Should leave deleted B and D; relocated F and G unmerged"
+  );
+  deepEqual(
+    mergeTelemetryCounts,
+    [
+      { name: "items", count: 8 },
+      { name: "remoteRevives", count: 1 },
+      { name: "localDeletes", count: 2 },
+    ],
+    "Should record telemetry for remote item and local folder deletions"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkFFFF", "bookmarkGGGG", "menu"],
+      deleted: ["bookmarkCCCC", "bookmarkEEEE", "folderBBBBBB", "folderDDDDDD"],
+    },
+    "Should upload relocated remote orphans and menu"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A (remote)",
+          url: "http://example.com/a-remote",
+        },
+        {
+          guid: "bookmarkFFFF",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "F (remote)",
+          url: "http://example.com/f-remote",
+        },
+        {
+          guid: "bookmarkGGGG",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "G (remote)",
+          url: "http://example.com/g-remote",
+        },
+      ],
+    },
+    "Should restore A and relocate (F G) to menu"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["bookmarkCCCC", "bookmarkEEEE", "folderBBBBBB", "folderDDDDDD"],
+    "Should store local tombstones for deleted items; remove for undeleted"
+  );
+  Assert.ok(
+    tombstones.every(({ dateRemoved }) =>
+      is_time_ordered(now, dateRemoved.getTime())
+    ),
+    "Local tombstone timestamps should be recent"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_move_to_new_then_delete() {
+  let buf = await openMirror("move_to_new_then_delete");
+
+  info("Set up mirror: A > B > (C D)");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "folderBBBBBB",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "B",
+            children: [
+              {
+                guid: "bookmarkCCCC",
+                url: "http://example.com/c",
+                title: "C",
+              },
+              {
+                guid: "bookmarkDDDD",
+                url: "http://example.com/d",
+                title: "D",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["folderBBBBBB"],
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "folderAAAAAA",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC", "bookmarkDDDD"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: E > A, delete E");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "folderEEEEEE",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "E",
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: "folderAAAAAA",
+    parentGuid: "folderEEEEEE",
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  // E isn't synced, so we shouldn't upload a tombstone.
+  await PlacesUtils.bookmarks.remove("folderEEEEEE");
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "bookmarkCCCC",
+      parentid: "folderBBBBBB",
+      type: "bookmark",
+      title: "C (remote)",
+      bmkUri: "http://example.com/c-remote",
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkCCCC", PlacesUtils.bookmarks.toolbarGuid],
+    "Should leave revived C and toolbar with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkCCCC", "menu", "toolbar"],
+      deleted: ["bookmarkDDDD", "folderAAAAAA", "folderBBBBBB"],
+    },
+    "Should upload records for Menu > C, Toolbar"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C (remote)",
+              url: "http://example.com/c-remote",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should move C to closest surviving parent"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["bookmarkDDDD", "folderAAAAAA", "folderBBBBBB"],
+    "Should store local tombstones for (D A B)"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_nonexistent_on_one_side() {
+  let buf = await openMirror("nonexistent_on_one_side");
+
+  info("Set up empty mirror");
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // A doesn't exist in the mirror.
+  info("Create local tombstone for nonexistent remote item A");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkAAAA",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "A",
+    url: "http://example.com/a",
+    // Pretend a bookmark restore added A, so that we'll write a tombstone when
+    // we remove it.
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE,
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkAAAA");
+
+  // B doesn't exist in Places, and we don't currently persist tombstones (bug
+  // 1343103), so we should ignore it.
+  info("Create remote tombstone for nonexistent local item B");
+  await storeRecords(buf, [
+    {
+      id: "bookmarkBBBB",
+      deleted: true,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid],
+    "Should leave menu with new remote structure unmerged"
+  );
+
+  let menuInfo = await PlacesUtils.bookmarks.fetch(
+    PlacesUtils.bookmarks.menuGuid
+  );
+
+  // We should still upload a record for the menu, since we changed its
+  // children when we added then removed A.
+  deepEqual(changesToUpload, {
+    menu: {
+      tombstone: false,
+      counter: 2,
+      synced: false,
+      cleartext: {
+        id: "menu",
+        type: "folder",
+        parentid: "places",
+        hasDupe: true,
+        parentName: "",
+        dateAdded: menuInfo.dateAdded.getTime(),
+        title: BookmarksMenuTitle,
+        children: [],
+      },
+    },
+  });
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_clear_folder_then_delete() {
+  let buf = await openMirror("clear_folder_then_delete");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+          },
+        ],
+      },
+      {
+        guid: "folderDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        children: [
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+          },
+          {
+            guid: "bookmarkFFFF",
+            url: "http://example.com/f",
+            title: "F",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "folderDDDDDD"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB", "bookmarkCCCC"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkEEEE", "bookmarkFFFF"],
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes: Menu > E, Mobile > F, delete D");
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkEEEE",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    index: 0,
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkFFFF",
+    parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    index: 0,
+  });
+  await PlacesUtils.bookmarks.remove("folderDDDDDD");
+
+  info("Make remote changes: Menu > B, Unfiled > C, delete A");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkBBBB", "folderDDDDDD"],
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+    {
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkCCCC"],
+    },
+    {
+      id: "bookmarkCCCC",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "C",
+      bmkUri: "http://example.com/c",
+    },
+    {
+      id: "folderAAAAAA",
+      deleted: true,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid, PlacesUtils.bookmarks.mobileGuid],
+    "Should leave menu and mobile with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkEEEE", "bookmarkFFFF", "menu", "mobile"],
+      deleted: ["folderDDDDDD"],
+    },
+    "Should upload locally moved and deleted items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "E",
+              url: "http://example.com/e",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkFFFF",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "F",
+              url: "http://example.com/f",
+            },
+          ],
+        },
+      ],
+    },
+    "Should not orphan moved children of a deleted folder"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["folderDDDDDD"],
+    "Should store local tombstone for D"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_newer_move_to_deleted() {
+  let buf = await openMirror("test_newer_move_to_deleted");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+        ],
+      },
+      {
+        guid: "folderCCCCCC",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "C",
+        children: [
+          {
+            guid: "bookmarkDDDD",
+            url: "http://example.com/d",
+            title: "D",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "folderCCCCCC"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "menu",
+        type: "folder",
+        title: "C",
+        children: ["bookmarkDDDD"],
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderCCCCCC",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let now = Date.now();
+
+  // A will have a newer local timestamp. However, we should *not* revert
+  // remotely moving B to the toolbar. (Locally, B exists in A, but we
+  // deleted the now-empty A remotely).
+  info("Make local changes: A > E, Toolbar > D, delete C");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkEEEE",
+    parentGuid: "folderAAAAAA",
+    title: "E",
+    url: "http://example.com/e",
+    dateAdded: new Date(now),
+    lastModified: new Date(now),
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkDDDD",
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    index: 0,
+    lastModified: new Date(now),
+  });
+  await PlacesUtils.bookmarks.remove("folderCCCCCC");
+
+  // C will have a newer remote timestamp. However, we should *not* revert
+  // locally moving D to the toolbar. (Locally, D exists in C, but we
+  // deleted the now-empty C locally).
+  info("Make remote changes: C > F, Toolbar > B, delete A");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["folderCCCCCC"],
+    },
+    {
+      id: "folderCCCCCC",
+      parentid: "menu",
+      type: "folder",
+      title: "C",
+      children: ["bookmarkDDDD", "bookmarkFFFF"],
+      modified: now / 1000 + 5,
+    },
+    {
+      id: "bookmarkFFFF",
+      parentid: "folderCCCCCC",
+      type: "bookmark",
+      title: "F",
+      bmkUri: "http://example.com/f",
+    },
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkBBBB"],
+      modified: now / 1000 - 5,
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "toolbar",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+      modified: now / 1000 - 5,
+    },
+    {
+      id: "folderAAAAAA",
+      deleted: true,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    localTimeSeconds: now / 1000,
+    remoteTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      "bookmarkFFFF",
+      "folderCCCCCC",
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+    ],
+    "Should leave deleted C; revived F and roots with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [
+        "bookmarkDDDD",
+        "bookmarkEEEE",
+        "bookmarkFFFF",
+        "menu",
+        "toolbar",
+      ],
+      deleted: ["folderCCCCCC"],
+    },
+    "Should upload new and moved items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "E",
+              url: "http://example.com/e",
+            },
+            {
+              guid: "bookmarkFFFF",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "F",
+              url: "http://example.com/f",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkDDDD",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "D",
+              url: "http://example.com/d",
+            },
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should not decide to keep newly moved items in deleted parents"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["folderCCCCCC"],
+    "Should store local tombstone for C"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_remotely_deleted_also_removes_keyword() {
+  let buf = await openMirror("remotely_deleted_removes_keyword");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+        keyword: "keyworda",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+        keyword: "keywordb",
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        keyword: "keyworda",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        keyword: "keywordb",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // Validate the keywords exists
+  let has_keyword_a = await PlacesUtils.keywords.fetch({
+    url: "http://example.com/a",
+  });
+  Assert.equal(has_keyword_a.keyword, "keyworda");
+
+  let has_keyword_b = await PlacesUtils.keywords.fetch({
+    url: "http://example.com/b",
+  });
+  Assert.equal(has_keyword_b.keyword, "keywordb");
+
+  info("Make remote changes: delete A & B");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: [],
+    },
+    {
+      id: "bookmarkAAAA",
+      deleted: true,
+    },
+    {
+      id: "bookmarkBBBB",
+      deleted: true,
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [],
+      deleted: [],
+    },
+    "No local changes done"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+    },
+    "Should've remove A & B from menu"
+  );
+
+  // Validate the keyword no longer exists after removing the bookmark
+  let no_keyword_a = await PlacesUtils.keywords.fetch({
+    url: "http://example.com/a",
+  });
+  Assert.equal(no_keyword_a, null);
+
+  // Both keywords should've been removed after the sync
+  let no_keyword_b = await PlacesUtils.keywords.fetch({
+    url: "http://example.com/b",
+  });
+  Assert.equal(no_keyword_b, null);
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Should not store local tombstones");
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_haschanges.js b/toolkit/components/places/tests/sync/test_bookmark_haschanges.js
new file mode 100644
index 0000000000..32cfd050aa
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_haschanges.js
@@ -0,0 +1,228 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_no_changes() {
+  let buf = await openMirror("nochanges");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: [],
+      },
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: [],
+      },
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: [],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let controller = new AbortController();
+  const wasMerged = await buf.merge(controller.signal);
+  Assert.ok(!wasMerged);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_changes_remote() {
+  let buf = await openMirror("remote_changes");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "New Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+    { needsMerge: true }
+  );
+
+  let controller = new AbortController();
+  const wasMerged = await buf.merge(controller.signal);
+  Assert.ok(wasMerged);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_changes_local() {
+  let buf = await openMirror("local_changes");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await PlacesUtils.bookmarks.update({
+    guid: "mozBmk______",
+    title: "New Mozilla!",
+  });
+
+  let controller = new AbortController();
+  const wasMerged = await buf.merge(controller.signal);
+  Assert.ok(wasMerged);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_changes_deleted_bookmark() {
+  let buf = await openMirror("delete_bookmark");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let wait = PlacesTestUtils.waitForNotification("bookmark-removed", events =>
+    events.some(event => event.parentGuid == PlacesUtils.bookmarks.tagsGuid)
+  );
+  await PlacesUtils.bookmarks.remove("mozBmk______");
+
+  await wait;
+  // Wait for everything to be finished
+  await new Promise(resolve => Services.tm.dispatchToMainThread(resolve));
+  let controller = new AbortController();
+  const wasMerged = await buf.merge(controller.signal);
+  Assert.ok(wasMerged);
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_kinds.js b/toolkit/components/places/tests/sync/test_bookmark_kinds.js
new file mode 100644
index 0000000000..3372757532
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_kinds.js
@@ -0,0 +1,312 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_queries() {
+  let buf = await openMirror("queries");
+
+  info("Set up places");
+
+  // create a tag and grab the local folder ID.
+  let tag = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    title: "a-tag",
+  });
+
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // this entry has a tag= query param for a tag that exists.
+        guid: "queryAAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title: "TAG_QUERY query",
+        url: `place:tag=a-tag&&sort=14&maxResults=10`,
+      },
+      {
+        // this entry has a tag= query param for a tag that doesn't exist.
+        guid: "queryBBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title: "TAG_QUERY query but invalid folder id",
+        url: `place:tag=b-tag&sort=14&maxResults=10`,
+      },
+      {
+        // this entry has no tag= query param.
+        guid: "queryCCCCCCC",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title: "TAG_QUERY without a folder at all",
+        url: "place:sort=14&maxResults=10",
+      },
+      {
+        // this entry has only a tag= query.
+        guid: "queryDDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        title: "TAG_QUERY without a folder at all",
+        url: "place:tag=a-tag",
+      },
+    ],
+  });
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "queryEEEEEEE",
+          "queryFFFFFFF",
+          "queryGGGGGGG",
+          "queryHHHHHHH",
+          "queryIIIIIII",
+        ],
+      },
+      {
+        // Legacy tag query.
+        id: "queryEEEEEEE",
+        parentid: "toolbar",
+        type: "query",
+        title: "E",
+        bmkUri: "place:type=7&folder=999",
+        folderName: "taggy",
+      },
+      {
+        // New tag query.
+        id: "queryFFFFFFF",
+        parentid: "toolbar",
+        type: "query",
+        title: "F",
+        bmkUri: "place:tag=a-tag",
+        folderName: "a-tag",
+      },
+      {
+        // Legacy tag query referencing the same tag as the new query.
+        id: "queryGGGGGGG",
+        parentid: "toolbar",
+        type: "query",
+        title: "G",
+        bmkUri: "place:type=7&folder=111&something=else",
+        folderName: "a-tag",
+      },
+      {
+        // Legacy folder lookup query.
+        id: "queryHHHHHHH",
+        parentid: "toolbar",
+        type: "query",
+        title: "H",
+        bmkUri: "place:folder=1",
+      },
+      {
+        // Legacy tag query with invalid tag folder name.
+        id: "queryIIIIIII",
+        parentid: "toolbar",
+        type: "query",
+        title: "I",
+        bmkUri: "place:type=7&folder=222",
+        folderName: "    ",
+      },
+    ])
+  );
+
+  info("Create records to upload");
+  let changes = await buf.apply();
+  deepEqual(
+    Object.keys(changes),
+    [
+      "menu",
+      "toolbar",
+      "queryAAAAAAA",
+      "queryBBBBBBB",
+      "queryCCCCCCC",
+      "queryDDDDDDD",
+      "queryEEEEEEE",
+      "queryGGGGGGG",
+      "queryHHHHHHH",
+      "queryIIIIIII",
+    ],
+    "Should upload roots, new queries, and rewritten queries"
+  );
+  Assert.strictEqual(changes.queryAAAAAAA.cleartext.folderName, tag.title);
+  Assert.strictEqual(changes.queryBBBBBBB.cleartext.folderName, "b-tag");
+  Assert.strictEqual(changes.queryCCCCCCC.cleartext.folderName, undefined);
+  Assert.strictEqual(changes.queryDDDDDDD.cleartext.folderName, tag.title);
+  Assert.strictEqual(changes.queryIIIIIII.tombstone, true);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.toolbarGuid,
+    {
+      guid: PlacesUtils.bookmarks.toolbarGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 1,
+      title: BookmarksToolbarTitle,
+      children: [
+        {
+          guid: "queryEEEEEEE",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "E",
+          url: "place:tag=taggy",
+        },
+        {
+          guid: "queryFFFFFFF",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "F",
+          url: "place:tag=a-tag",
+        },
+        {
+          guid: "queryGGGGGGG",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "G",
+          url: "place:tag=a-tag",
+        },
+        {
+          guid: "queryHHHHHHH",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 3,
+          title: "H",
+          url: "place:folder=1&excludeItems=1",
+        },
+      ],
+    },
+    "Should rewrite legacy remote queries"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_different_but_compatible_bookmark_types() {
+  let buf = await openMirror("partial_queries");
+  try {
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.menuGuid,
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          title: "not yet a query",
+          url: "about:blank",
+        },
+        {
+          guid: "bookmarkBBBB",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          title: "a query",
+          url: "place:foo",
+        },
+      ],
+    });
+
+    let changes = await buf.apply();
+    // We should have an outgoing record for bookmarkA with type=bookmark
+    // and bookmarkB with type=query.
+    Assert.equal(changes.bookmarkAAAA.cleartext.type, "bookmark");
+    Assert.equal(changes.bookmarkBBBB.cleartext.type, "query");
+
+    // Now pretend that same records are already on the server.
+    await storeRecords(
+      buf,
+      [
+        {
+          id: "menu",
+          parentid: "places",
+          type: "folder",
+          children: ["bookmarkAAAA", "bookmarkBBBB"],
+        },
+        {
+          id: "bookmarkAAAA",
+          parentid: "menu",
+          type: "bookmark",
+          title: "not yet a query",
+          bmkUri: "about:blank",
+        },
+        {
+          id: "bookmarkBBBB",
+          parentid: "menu",
+          type: "query",
+          title: "a query",
+          bmkUri: "place:foo",
+        },
+      ],
+      { needsMerge: false }
+    );
+    await PlacesTestUtils.markBookmarksAsSynced();
+
+    // change the url of bookmarkA to be a "real" query and of bookmarkB to
+    // no longer be a query.
+    await PlacesUtils.bookmarks.update({
+      guid: "bookmarkAAAA",
+      url: "place:type=6&sort=14&maxResults=10",
+    });
+    await PlacesUtils.bookmarks.update({
+      guid: "bookmarkBBBB",
+      url: "about:robots",
+    });
+
+    changes = await buf.apply();
+    // We should have an outgoing record for bookmarkA with type=query and
+    // for bookmarkB with type=bookmark
+    Assert.equal(changes.bookmarkAAAA.cleartext.type, "query");
+    Assert.equal(changes.bookmarkBBBB.cleartext.type, "bookmark");
+  } finally {
+    await buf.finalize();
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesSyncUtils.bookmarks.reset();
+  }
+});
+
+add_task(async function test_incompatible_types() {
+  try {
+    let buf = await openMirror("incompatible_types");
+
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.menuGuid,
+      children: [
+        {
+          guid: "AAAAAAAAAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          title: "a bookmark",
+          url: "about:blank",
+        },
+      ],
+    });
+
+    await buf.apply();
+
+    // Now pretend that same records are already on the server with incompatible
+    // types.
+    await storeRecords(
+      buf,
+      [
+        {
+          id: "menu",
+          parentid: "places",
+          type: "folder",
+          children: ["AAAAAAAAAAAA"],
+        },
+        {
+          id: "AAAAAAAAAAAA",
+          parentid: "menu",
+          type: "folder",
+          title: "conflicting folder",
+        },
+      ],
+      { needsMerge: true }
+    );
+    await PlacesTestUtils.markBookmarksAsSynced();
+
+    await Assert.rejects(
+      buf.apply(),
+      /Can't merge local Bookmark <guid: AAAAAAAAAAAA> and remote Folder <guid: AAAAAAAAAAAA>/
+    );
+  } finally {
+    await PlacesUtils.bookmarks.eraseEverything();
+    await PlacesSyncUtils.bookmarks.reset();
+  }
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_mirror_meta.js b/toolkit/components/places/tests/sync/test_bookmark_mirror_meta.js
new file mode 100644
index 0000000000..6c475daab6
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_mirror_meta.js
@@ -0,0 +1,193 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_highWaterMark() {
+  let buf = await openMirror("highWaterMark");
+
+  strictEqual(
+    await buf.getCollectionHighWaterMark(),
+    0,
+    "High water mark should be 0 without items"
+  );
+
+  await buf.setCollectionLastModified(123.45);
+  equal(
+    await buf.getCollectionHighWaterMark(),
+    123.45,
+    "High water mark should be last modified time without items"
+  );
+
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: [],
+      modified: 50,
+    },
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      children: [],
+      modified: 123.95,
+    },
+  ]);
+  equal(
+    await buf.getCollectionHighWaterMark(),
+    123.45,
+    "High water mark should be last modified time if items are older"
+  );
+
+  await storeRecords(buf, [
+    {
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      children: [],
+      modified: 125.45,
+    },
+  ]);
+  equal(
+    await buf.getCollectionHighWaterMark(),
+    124.45,
+    "High water mark should be modified time - 1s of newest record if exists"
+  );
+
+  await buf.finalize();
+});
+
+add_task(async function test_ensureCurrentSyncId() {
+  let buf = await openMirror("ensureCurrentSyncId");
+
+  await buf.ensureCurrentSyncId("syncIdAAAAAA");
+  equal(
+    await buf.getCollectionHighWaterMark(),
+    0,
+    "High water mark should be 0 after setting sync ID"
+  );
+
+  info("Insert items and set collection last modified");
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+        modified: 125.45,
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        children: [],
+      },
+    ],
+    { needsMerge: false }
+  );
+  await buf.setCollectionLastModified(123.45);
+
+  info("Set matching sync ID");
+  await buf.ensureCurrentSyncId("syncIdAAAAAA");
+  {
+    equal(
+      await buf.getSyncId(),
+      "syncIdAAAAAA",
+      "Should return existing sync ID"
+    );
+    strictEqual(
+      await buf.getCollectionHighWaterMark(),
+      124.45,
+      "Different sync ID should reset high water mark"
+    );
+
+    let itemRows = await buf.db.execute(`
+      SELECT guid, needsMerge FROM items
+      ORDER BY guid`);
+    let itemInfos = itemRows.map(row => ({
+      guid: row.getResultByName("guid"),
+      needsMerge: !!row.getResultByName("needsMerge"),
+    }));
+    deepEqual(
+      itemInfos,
+      [
+        {
+          guid: "folderAAAAAA",
+          needsMerge: false,
+        },
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          needsMerge: false,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          needsMerge: true,
+        },
+        {
+          guid: PlacesUtils.bookmarks.rootGuid,
+          needsMerge: false,
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          needsMerge: true,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          needsMerge: true,
+        },
+      ],
+      "Matching sync ID should not reset items"
+    );
+  }
+
+  info("Set different sync ID");
+  await buf.ensureCurrentSyncId("syncIdBBBBBB");
+  {
+    equal(
+      await buf.getSyncId(),
+      "syncIdBBBBBB",
+      "Should replace existing sync ID"
+    );
+    strictEqual(
+      await buf.getCollectionHighWaterMark(),
+      0,
+      "Different sync ID should reset high water mark"
+    );
+
+    let itemRows = await buf.db.execute(`
+      SELECT guid, needsMerge FROM items
+      ORDER BY guid`);
+    let itemInfos = itemRows.map(row => ({
+      guid: row.getResultByName("guid"),
+      needsMerge: !!row.getResultByName("needsMerge"),
+    }));
+    deepEqual(
+      itemInfos,
+      [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          needsMerge: true,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          needsMerge: true,
+        },
+        {
+          guid: PlacesUtils.bookmarks.rootGuid,
+          needsMerge: false,
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          needsMerge: true,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          needsMerge: true,
+        },
+      ],
+      "Different sync ID should reset items"
+    );
+  }
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_mirror_migration.js b/toolkit/components/places/tests/sync/test_bookmark_mirror_migration.js
new file mode 100644
index 0000000000..86cf45eb0f
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_mirror_migration.js
@@ -0,0 +1,246 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Keep in sync with `SyncedBookmarksMirror.jsm`.
+const CURRENT_MIRROR_SCHEMA_VERSION = 9;
+
+// The oldest schema version that we support. Any databases with schemas older
+// than this will be dropped and recreated.
+const OLDEST_SUPPORTED_MIRROR_SCHEMA_VERSION = 5;
+
+async function getIndexNames(db, table, schema = "mirror") {
+  let rows = await db.execute(`PRAGMA ${schema}.index_list(${table})`);
+  let names = [];
+  for (let row of rows) {
+    // Column 4 is `c` if the index was created via `CREATE INDEX`, `u` if
+    // via `UNIQUE`, and `pk` if via `PRIMARY KEY`.
+    let wasCreated = row.getResultByIndex(3) == "c";
+    if (wasCreated) {
+      // Column 2 is the name of the index.
+      names.push(row.getResultByIndex(1));
+    }
+  }
+  return names.sort();
+}
+
+add_task(async function test_migrate_after_downgrade() {
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let dbFile = await setupFixtureFile("mirror_v5.sqlite");
+  let oldBuf = await SyncedBookmarksMirror.open({
+    path: dbFile.path,
+    recordStepTelemetry() {},
+    recordValidationTelemetry() {},
+  });
+
+  info("Downgrade schema version to oldest supported");
+  await oldBuf.db.setSchemaVersion(
+    OLDEST_SUPPORTED_MIRROR_SCHEMA_VERSION,
+    "mirror"
+  );
+  await oldBuf.finalize();
+
+  let buf = await SyncedBookmarksMirror.open({
+    path: dbFile.path,
+    recordStepTelemetry() {},
+    recordValidationTelemetry() {},
+  });
+
+  // All migrations between `OLDEST_SUPPORTED_MIRROR_SCHEMA_VERSION` should
+  // be idempotent. When we downgrade, we roll back the schema version, but
+  // leave the schema changes in place, since we can't anticipate what a
+  // future version will change.
+  let schemaVersion = await buf.db.getSchemaVersion("mirror");
+  equal(
+    schemaVersion,
+    CURRENT_MIRROR_SCHEMA_VERSION,
+    "Should upgrade downgraded mirror schema"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// Migrations between 5 and 7 add three indexes.
+add_task(async function test_migrate_from_5_to_current() {
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let dbFile = await setupFixtureFile("mirror_v5.sqlite");
+  let buf = await SyncedBookmarksMirror.open({
+    path: dbFile.path,
+    recordStepTelemetry() {},
+    recordValidationTelemetry() {},
+  });
+
+  let schemaVersion = await buf.db.getSchemaVersion("mirror");
+  equal(
+    schemaVersion,
+    CURRENT_MIRROR_SCHEMA_VERSION,
+    "Should upgrade mirror schema to current version"
+  );
+
+  let itemsIndexNames = await getIndexNames(buf.db, "items");
+  deepEqual(
+    itemsIndexNames,
+    ["itemKeywords", "itemURLs"],
+    "Should add two indexes on items"
+  );
+
+  let structureIndexNames = await getIndexNames(buf.db, "structure");
+  deepEqual(
+    structureIndexNames,
+    ["structurePositions"],
+    "Should add an index on structure"
+  );
+
+  let changesToUpload = await buf.apply();
+  deepEqual(changesToUpload, {}, "Shouldn't flag any items for reupload");
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAAA",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A",
+          url: "http://example.com/a",
+        },
+        {
+          guid: "bookmarkBBBB",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "B",
+          url: "http://example.com/b",
+          keyword: "hi",
+        },
+      ],
+    },
+    "Should apply mirror tree after migrating"
+  );
+
+  let keywordEntry = await PlacesUtils.keywords.fetch("hi");
+  equal(
+    keywordEntry.url.href,
+    "http://example.com/b",
+    "Should apply keyword from migrated mirror"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// Migrations between 1 and 2 discard the entire database.
+add_task(async function test_migrate_from_1_to_2() {
+  let dbFile = await setupFixtureFile("mirror_v1.sqlite");
+  let buf = await SyncedBookmarksMirror.open({
+    path: dbFile.path,
+  });
+  ok(
+    buf.wasCorrupt,
+    "Migrating from unsupported version should mark database as corrupt"
+  );
+  await buf.finalize();
+});
+
+add_task(async function test_database_corrupt() {
+  let corruptFile = await setupFixtureFile("mirror_corrupt.sqlite");
+  let buf = await SyncedBookmarksMirror.open({
+    path: corruptFile.path,
+  });
+  ok(buf.wasCorrupt, "Opening corrupt database should mark it as such");
+  await buf.finalize();
+});
+
+add_task(async function test_migrate_v7_v9() {
+  let buf = await openMirror("test_migrate_v7_v9");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+      },
+    ],
+  });
+
+  await buf.db.execute(
+    `UPDATE moz_bookmarks
+     SET syncChangeCounter = 0,
+         syncStatus = ${PlacesUtils.bookmarks.SYNC_STATUS.NEW}`
+  );
+
+  // setup the mirror.
+  await storeRecords(buf, [
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: [],
+    },
+  ]);
+
+  await buf.db.setSchemaVersion(7, "mirror");
+  await buf.finalize();
+
+  // reopen it.
+  buf = await openMirror("test_migrate_v7_v9");
+  Assert.equal(await buf.db.getSchemaVersion("mirror"), 9, "did upgrade");
+
+  let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+    PlacesUtils.bookmarks.menuGuid
+  );
+  let [fieldsA, fieldsB, fieldsMenu] = fields;
+
+  // 'A' was in the mirror - should now be _NORMAL
+  Assert.equal(fieldsA.guid, "bookmarkAAAA");
+  Assert.equal(fieldsA.syncStatus, PlacesUtils.bookmarks.SYNC_STATUS.NORMAL);
+  // 'B' was not in the mirror so should be untouched.
+  Assert.equal(fieldsB.guid, "bookmarkBBBB");
+  Assert.equal(fieldsB.syncStatus, PlacesUtils.bookmarks.SYNC_STATUS.NEW);
+  // 'menu' was in the mirror - should now be _NORMAL
+  Assert.equal(fieldsMenu.guid, PlacesUtils.bookmarks.menuGuid);
+  Assert.equal(fieldsMenu.syncStatus, PlacesUtils.bookmarks.SYNC_STATUS.NORMAL);
+  await buf.finalize();
+});
+
+add_task(async function test_migrate_v8_v9() {
+  let dbFile = await setupFixtureFile("mirror_v8.sqlite");
+  let buf = await SyncedBookmarksMirror.open({
+    path: dbFile.path,
+    recordStepTelemetry() {},
+    recordValidationTelemetry() {},
+  });
+
+  Assert.equal(await buf.db.getSchemaVersion("mirror"), 9, "did upgrade");
+
+  // Verify the new column is there
+  Assert.ok(await buf.db.execute("SELECT unknownFields FROM items"));
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_observer_recorder.js b/toolkit/components/places/tests/sync/test_bookmark_observer_recorder.js
new file mode 100644
index 0000000000..16d8ed746c
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_observer_recorder.js
@@ -0,0 +1,670 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+async function promiseAllURLFrecencies() {
+  let frecencies = new Map();
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`
+    SELECT url, frecency, recalc_frecency
+    FROM moz_places
+    WHERE url_hash BETWEEN hash('http', 'prefix_lo') AND
+                           hash('http', 'prefix_hi')`);
+  for (let row of rows) {
+    frecencies.set(row.getResultByName("url"), {
+      frecency: row.getResultByName("frecency"),
+      recalc: row.getResultByName("recalc_frecency"),
+    });
+  }
+  return frecencies;
+}
+
+function mapFilterIterator(iter, fn) {
+  let results = [];
+  for (let value of iter) {
+    let newValue = fn(value);
+    if (newValue) {
+      results.push(newValue);
+    }
+  }
+  return results;
+}
+
+add_task(async function test_update_frecencies() {
+  let buf = await openMirror("update_frecencies");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // Not modified in mirror; shouldn't recalculate frecency.
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        // URL changed to B1 in mirror; should recalculate frecency for B
+        // and B1, using existing frecency to determine order.
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+      {
+        // URL changed to new URL in mirror, should recalculate frecency
+        // for new URL first, before B1.
+        guid: "bookmarkBBB1",
+        title: "B1",
+        url: "http://example.com/b1",
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkBBBB", "bookmarkBBB1"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkBBB1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B1",
+        bmkUri: "http://example.com/b1",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local changes");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // Query; shouldn't recalculate frecency.
+        guid: "queryCCCCCCC",
+        title: "C",
+        url: "place:type=6&sort=14&maxResults=10",
+      },
+    ],
+  });
+
+  info("Calculate frecencies for all local URLs");
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkAAAA", "bookmarkBBBB", "bookmarkBBB1"],
+    },
+    {
+      id: "unfiled",
+      parentid: "places",
+      type: "folder",
+      children: [
+        "bookmarkBBB2",
+        "bookmarkDDDD",
+        "bookmarkEEEE",
+        "queryFFFFFFF",
+      ],
+    },
+    {
+      // Existing bookmark changed to existing URL.
+      id: "bookmarkBBBB",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b1",
+    },
+    {
+      // Existing bookmark with new URL; should recalculate frecency first.
+      id: "bookmarkBBB1",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B1",
+      bmkUri: "http://example.com/b11",
+    },
+    {
+      id: "bookmarkBBB2",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "B2",
+      bmkUri: "http://example.com/b",
+    },
+    {
+      // New bookmark with new URL; should recalculate frecency first.
+      id: "bookmarkDDDD",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: null,
+      bmkUri: "http://example.com/d",
+    },
+    {
+      // New bookmark with new URL.
+      id: "bookmarkEEEE",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "E",
+      bmkUri: "http://example.com/e",
+    },
+    {
+      // New query; shouldn't count against limit.
+      id: "queryFFFFFFF",
+      parentid: "unfiled",
+      type: "query",
+      title: "F",
+      bmkUri: `place:parent=${PlacesUtils.bookmarks.menuGuid}`,
+    },
+  ]);
+
+  info("Apply new items and recalculate 3 frecencies");
+  await buf.apply();
+  await PlacesFrecencyRecalculator.recalculateSomeFrecencies({ chunkSize: 3 });
+
+  {
+    let frecencies = await promiseAllURLFrecencies();
+    let urlsWithFrecency = mapFilterIterator(
+      frecencies.entries(),
+      ([href, { frecency, recalc }]) => (recalc == 0 ? href : null)
+    );
+
+    // A is unchanged, and we should recalculate frecency for three more
+    // random URLs.
+    equal(
+      urlsWithFrecency.length,
+      4,
+      "Should keep unchanged frecency and recalculate 3"
+    );
+    let unexpectedURLs = CommonUtils.difference(
+      urlsWithFrecency,
+      new Set([
+        // A is unchanged.
+        "http://example.com/a",
+
+        // B11, D, and E are new URLs.
+        "http://example.com/b11",
+        "http://example.com/d",
+        "http://example.com/e",
+
+        // B and B1 are existing, changed URLs.
+        "http://example.com/b",
+        "http://example.com/b1",
+      ])
+    );
+    ok(
+      !unexpectedURLs.size,
+      "Should recalculate frecency for new and changed URLs only"
+    );
+  }
+
+  info("Change non-URL property of D");
+  await storeRecords(buf, [
+    {
+      id: "bookmarkDDDD",
+      parentid: "unfiled",
+      type: "bookmark",
+      title: "D (remote)",
+      bmkUri: "http://example.com/d",
+    },
+  ]);
+
+  info("Apply new item and recalculate remaining frecencies");
+  await buf.apply();
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  {
+    let frecencies = await promiseAllURLFrecencies();
+    let urlsWithoutFrecency = mapFilterIterator(
+      frecencies.entries(),
+      ([href, { frecency, recalc }]) => (recalc == 1 ? href : null)
+    );
+    deepEqual(
+      urlsWithoutFrecency,
+      [],
+      "Should finish calculating remaining frecencies"
+    );
+  }
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+async function setupLocalTree(localTimeSeconds) {
+  let dateAdded = new Date(localTimeSeconds * 1000);
+  let lastModified = new Date(localTimeSeconds * 1000);
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        dateAdded,
+        lastModified,
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            title: "B",
+            url: "http://example.com/b",
+            dateAdded,
+            lastModified,
+          },
+          {
+            guid: "bookmarkCCCC",
+            title: "C",
+            url: "http://example.com/c",
+            dateAdded,
+            lastModified,
+          },
+        ],
+      },
+      {
+        guid: "bookmarkDDDD",
+        title: null,
+        url: "http://example.com/d",
+        dateAdded,
+        lastModified,
+      },
+    ],
+  });
+}
+
+// This test ensures we clean up the temp tables between merges, and don't throw
+// constraint errors recording observer notifications.
+add_task(async function test_apply_then_revert() {
+  let buf = await openMirror("apply_then_revert");
+
+  let now = Date.now() / 1000;
+  let localTimeSeconds = now - 180;
+
+  info("Set up initial local tree and mirror");
+  await setupLocalTree(localTimeSeconds);
+  let recordsToUpload = await buf.apply({
+    localTimeSeconds,
+    remoteTimeSeconds: now,
+  });
+  await storeChangesInMirror(buf, recordsToUpload);
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkEEE1",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "E",
+    url: "http://example.com/e",
+    dateAdded: new Date(localTimeSeconds * 1000),
+    lastModified: new Date(localTimeSeconds * 1000),
+  });
+
+  info("Make remote changes");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkEEEE", "bookmarkFFFF"],
+      modified: now,
+    },
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      children: ["folderAAAAAA"],
+      modified: now,
+    },
+    {
+      id: "folderAAAAAA",
+      parentid: "toolbar",
+      type: "folder",
+      title: "A (remote)",
+      children: ["bookmarkCCCC", "bookmarkBBBB"],
+      modified: now,
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "folderAAAAAA",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b-remote",
+      modified: now,
+    },
+    {
+      id: "bookmarkDDDD",
+      deleted: true,
+      modified: now,
+    },
+    {
+      id: "bookmarkEEEE",
+      parentid: "menu",
+      type: "bookmark",
+      title: "E",
+      bmkUri: "http://example.com/e",
+      modified: now,
+    },
+    {
+      id: "bookmarkFFFF",
+      parentid: "menu",
+      type: "bookmark",
+      title: "F",
+      bmkUri: "http://example.com/f",
+      modified: now,
+    },
+  ]);
+
+  info("Apply remote changes, first time");
+  let firstTimeRecords = await buf.apply({
+    localTimeSeconds,
+    remoteTimeSeconds: now,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid],
+    "Should leave menu with new remote structure unmerged after first time"
+  );
+
+  info("Revert local tree");
+  let dateAdded = new Date(localTimeSeconds * 1000);
+  await PlacesSyncUtils.bookmarks.wipe();
+  await setupLocalTree(localTimeSeconds);
+  await PlacesTestUtils.markBookmarksAsSynced();
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkEEE1",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "E",
+    url: "http://example.com/e",
+    dateAdded,
+    lastModified: new Date(localTimeSeconds * 1000),
+  });
+  let localIdForD = await PlacesTestUtils.promiseItemId("bookmarkDDDD");
+
+  info("Apply remote changes, second time");
+  await buf.db.execute(
+    `
+    UPDATE items SET
+      needsMerge = 1
+    WHERE guid <> :rootGuid`,
+    { rootGuid: PlacesUtils.bookmarks.rootGuid }
+  );
+  let observer = expectBookmarkChangeNotifications();
+  let secondTimeRecords = await buf.apply({
+    localTimeSeconds,
+    remoteTimeSeconds: now,
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid],
+    "Should leave menu with new remote structure unmerged after second time"
+  );
+  deepEqual(
+    secondTimeRecords,
+    firstTimeRecords,
+    "Should stage identical records to upload, first and second time"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "bookmarkFFFF",
+    "bookmarkEEEE",
+    "folderAAAAAA",
+    "bookmarkCCCC",
+    "bookmarkBBBB",
+    PlacesUtils.bookmarks.menuGuid,
+  ]);
+  observer.check([
+    {
+      name: "bookmark-removed",
+      params: {
+        itemId: localIdForD,
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/d",
+        title: "", // null titles get turned into empty strings.
+        guid: "bookmarkDDDD",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+      },
+    },
+    {
+      name: "bookmark-guid-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkEEEE"),
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "",
+        guid: "bookmarkEEEE",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        isTagging: false,
+      },
+    },
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("bookmarkFFFF"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/f",
+        title: "F",
+        guid: "bookmarkFFFF",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkEEEE"),
+        oldIndex: 2,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkEEEE",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/e",
+        isTagging: false,
+        title: "E",
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("folderAAAAAA"),
+        oldIndex: 0,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        guid: "folderAAAAAA",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "",
+        isTagging: false,
+        title: "A (remote)",
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkCCCC",
+        oldParentGuid: "folderAAAAAA",
+        newParentGuid: "folderAAAAAA",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/c",
+        isTagging: false,
+        title: "C",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        oldIndex: 0,
+        newIndex: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkBBBB",
+        oldParentGuid: "folderAAAAAA",
+        newParentGuid: "folderAAAAAA",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/b-remote",
+        isTagging: false,
+        title: "B",
+        tags: "",
+        frecency: -1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("folderAAAAAA"),
+        title: "A (remote)",
+        guid: "folderAAAAAA",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      },
+    },
+    {
+      name: "bookmark-url-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/b-remote",
+        guid: "bookmarkBBBB",
+        parentGuid: "folderAAAAAA",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        isTagging: false,
+      },
+    },
+  ]);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "E",
+              url: "http://example.com/e",
+            },
+            {
+              guid: "bookmarkFFFF",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "F",
+              url: "http://example.com/f",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A (remote)",
+              children: [
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "C",
+                  url: "http://example.com/c",
+                },
+                {
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "B",
+                  url: "http://example.com/b-remote",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should apply new structure, second time"
+  );
+
+  await storeChangesInMirror(buf, secondTimeRecords);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_reconcile.js b/toolkit/components/places/tests/sync/test_bookmark_reconcile.js
new file mode 100644
index 0000000000..218e84beb6
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_reconcile.js
@@ -0,0 +1,191 @@
+// Get bookmarks which aren't marked as normally syncing and with no pending
+// changes.
+async function getBookmarksNotMarkedAsSynced() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.executeCached(
+    `
+    SELECT guid, syncStatus, syncChangeCounter FROM moz_bookmarks
+    WHERE syncChangeCounter > 1 OR syncStatus != :syncStatus
+    ORDER BY guid
+    `,
+    { syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL }
+  );
+  return rows.map(row => {
+    return {
+      guid: row.getResultByName("guid"),
+      syncStatus: row.getResultByName("syncStatus"),
+      syncChangeCounter: row.getResultByName("syncChangeCounter"),
+    };
+  });
+}
+
+add_task(async function test_reconcile_metadata() {
+  let buf = await openMirror("test_reconcile_metadata");
+
+  let olderDate = new Date(Date.now() - 100000);
+  info("Set up local tree");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        // this folder is going to reconcile exactly
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+        ],
+      },
+      {
+        // this folder's existing child isn't on the server (so will be
+        // outgoing) and also will take a new child from the server.
+        guid: "folderCCCCCC",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "C",
+        children: [
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+          },
+        ],
+      },
+      {
+        // This bookmark is going to take the remote title.
+        guid: "bookmarkFFFF",
+        url: "http://example.com/f",
+        title: "f",
+        dateAdded: olderDate,
+        lastModified: olderDate,
+      },
+    ],
+  });
+  // And a single, local-only bookmark in the toolbar.
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bookmarkTTTT",
+        url: "http://example.com/t",
+        title: "in the toolbar",
+        dateAdded: olderDate,
+        lastModified: olderDate,
+      },
+    ],
+  });
+  // Reset to prepare for our reconciled sync.
+  await PlacesSyncUtils.bookmarks.reset();
+  // setup the mirror.
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "folderCCCCCC", "bookmarkFFFF"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "menu",
+        type: "folder",
+        title: "C",
+        children: ["bookmarkDDDD"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderCCCCCC",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "menu",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+        dateAdded: olderDate,
+        modified: Date.now() / 1000 + 60,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: [],
+        index: 1,
+      },
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: [],
+        index: 3,
+      },
+    ])
+  );
+  info("Applying");
+  let changesToUpload = await buf.apply();
+  // We need to upload a bookmark and the parent as they didn't exist on the
+  // server. Since we always use the local state for roots (bug 1472241), we'll
+  // reupload them too.
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [
+        "bookmarkEEEE",
+        "bookmarkTTTT",
+        "folderCCCCCC",
+        "menu",
+        "mobile",
+        "toolbar",
+        "unfiled",
+      ],
+      deleted: [],
+    },
+    "Should upload the 2 local-only bookmarks and their parents"
+  );
+  // Check it took the remote thing we were expecting.
+  Assert.equal((await PlacesUtils.bookmarks.fetch("bookmarkFFFF")).title, "F");
+  // Most things should be synced and have no change counter.
+  let badGuids = await getBookmarksNotMarkedAsSynced();
+  Assert.deepEqual(badGuids, [
+    {
+      // The bookmark that was only on the server. Still have SYNC_STATUS_NEW
+      // as it's yet to be uploaded.
+      guid: "bookmarkEEEE",
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      syncChangeCounter: 1,
+    },
+    {
+      // This bookmark is local only so is yet to be uploaded.
+      guid: "bookmarkTTTT",
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      syncChangeCounter: 1,
+    },
+  ]);
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_structure_changes.js b/toolkit/components/places/tests/sync/test_bookmark_structure_changes.js
new file mode 100644
index 0000000000..cde4d5e751
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_structure_changes.js
@@ -0,0 +1,2966 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_value_structure_conflict() {
+  let buf = await openMirror("value_structure_conflict");
+
+  info("Set up mirror");
+  let dateAdded = new Date();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+            dateAdded,
+          },
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+            dateAdded,
+          },
+        ],
+      },
+      {
+        guid: "folderDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        children: [
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+            dateAdded,
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "folderDDDDDD"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB", "bookmarkCCCC"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkEEEE"],
+        modified: Date.now() / 1000 - 60,
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+        modified: Date.now() / 1000 - 60,
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local value change");
+  await PlacesUtils.bookmarks.update({
+    guid: "folderAAAAAA",
+    title: "A (local)",
+  });
+
+  info("Make local structure change");
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkBBBB",
+    parentGuid: "folderDDDDDD",
+    index: 0,
+  });
+
+  info("Make remote value change");
+  await storeRecords(buf, [
+    {
+      id: "folderDDDDDD",
+      parentid: "menu",
+      type: "folder",
+      title: "D (remote)",
+      children: ["bookmarkEEEE"],
+      modified: Date.now() / 1000 + 60,
+    },
+  ]);
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    remoteTimeSeconds: Date.now() / 1000,
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["folderDDDDDD"],
+    "Should leave D with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkBBBB", "folderAAAAAA", "folderDDDDDD"],
+      deleted: [],
+    },
+    "Should upload records for merged and new local items"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "folderAAAAAA",
+    "bookmarkEEEE",
+    "bookmarkBBBB",
+    "folderDDDDDD",
+  ]);
+  observer.check([
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkEEEE"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkEEEE",
+        oldParentGuid: "folderDDDDDD",
+        newParentGuid: "folderDDDDDD",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/e",
+        isTagging: false,
+        title: "E",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        oldIndex: 0,
+        newIndex: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkBBBB",
+        oldParentGuid: "folderDDDDDD",
+        newParentGuid: "folderDDDDDD",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/b",
+        isTagging: false,
+        title: "B",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("folderDDDDDD"),
+        title: "D (remote)",
+        guid: "folderDDDDDD",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+  ]);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "folderAAAAAA",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "A (local)",
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: "folderDDDDDD",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: "D (remote)",
+          children: [
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "E",
+              url: "http://example.com/e",
+            },
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+      ],
+    },
+    "Should reconcile structure and value changes"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_move() {
+  let buf = await openMirror("move");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "devFolder___",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "Dev",
+        children: [
+          {
+            guid: "mdnBmk______",
+            title: "MDN",
+            url: "https://developer.mozilla.org",
+          },
+          {
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            guid: "mozFolder___",
+            title: "Mozilla",
+            children: [
+              {
+                guid: "fxBmk_______",
+                title: "Get Firefox!",
+                url: "http://getfirefox.com/",
+              },
+              {
+                guid: "nightlyBmk__",
+                title: "Nightly",
+                url: "https://nightly.mozilla.org",
+              },
+            ],
+          },
+          {
+            guid: "wmBmk_______",
+            title: "Webmaker",
+            url: "https://webmaker.org",
+          },
+        ],
+      },
+      {
+        guid: "bzBmk_______",
+        title: "Bugzilla",
+        url: "https://bugzilla.mozilla.org",
+      },
+    ],
+  });
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: ["mozFolder___"],
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["devFolder___"],
+      },
+      {
+        // Moving to toolbar.
+        id: "devFolder___",
+        parentid: "toolbar",
+        type: "folder",
+        title: "Dev",
+        children: ["bzBmk_______", "wmBmk_______"],
+      },
+      {
+        // Moving to "Mozilla".
+        id: "mdnBmk______",
+        parentid: "mozFolder___",
+        type: "bookmark",
+        title: "MDN",
+        bmkUri: "https://developer.mozilla.org",
+      },
+      {
+        // Rearranging children and moving to unfiled.
+        id: "mozFolder___",
+        parentid: "unfiled",
+        type: "folder",
+        title: "Mozilla",
+        children: ["nightlyBmk__", "mdnBmk______", "fxBmk_______"],
+      },
+      {
+        id: "fxBmk_______",
+        parentid: "mozFolder___",
+        type: "bookmark",
+        title: "Get Firefox!",
+        bmkUri: "http://getfirefox.com/",
+      },
+      {
+        id: "nightlyBmk__",
+        parentid: "mozFolder___",
+        type: "bookmark",
+        title: "Nightly",
+        bmkUri: "https://nightly.mozilla.org",
+      },
+      {
+        id: "wmBmk_______",
+        parentid: "devFolder___",
+        type: "bookmark",
+        title: "Webmaker",
+        bmkUri: "https://webmaker.org",
+      },
+      {
+        id: "bzBmk_______",
+        parentid: "devFolder___",
+        type: "bookmark",
+        title: "Bugzilla",
+        bmkUri: "https://bugzilla.mozilla.org",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [],
+      deleted: [],
+    },
+    "Should not upload records for remotely moved items"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "devFolder___",
+    "mozFolder___",
+    "bzBmk_______",
+    "wmBmk_______",
+    "nightlyBmk__",
+    "mdnBmk______",
+    "fxBmk_______",
+  ]);
+  observer.check([
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("devFolder___"),
+        oldIndex: 0,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        guid: "devFolder___",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "",
+        isTagging: false,
+        title: "Dev",
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("mozFolder___"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        guid: "mozFolder___",
+        oldParentGuid: "devFolder___",
+        newParentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "",
+        isTagging: false,
+        title: "Mozilla",
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bzBmk_______"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bzBmk_______",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: "devFolder___",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "https://bugzilla.mozilla.org/",
+        isTagging: false,
+        title: "Bugzilla",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("wmBmk_______"),
+        oldIndex: 2,
+        newIndex: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "wmBmk_______",
+        oldParentGuid: "devFolder___",
+        newParentGuid: "devFolder___",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "https://webmaker.org/",
+        isTagging: false,
+        title: "Webmaker",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("nightlyBmk__"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "nightlyBmk__",
+        oldParentGuid: "mozFolder___",
+        newParentGuid: "mozFolder___",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "https://nightly.mozilla.org/",
+        isTagging: false,
+        title: "Nightly",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("mdnBmk______"),
+        oldIndex: 0,
+        newIndex: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "mdnBmk______",
+        oldParentGuid: "devFolder___",
+        newParentGuid: "mozFolder___",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "https://developer.mozilla.org/",
+        isTagging: false,
+        title: "MDN",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("fxBmk_______"),
+        oldIndex: 0,
+        newIndex: 2,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "fxBmk_______",
+        oldParentGuid: "mozFolder___",
+        newParentGuid: "mozFolder___",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://getfirefox.com/",
+        isTagging: false,
+        title: "Get Firefox!",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+  ]);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "devFolder___",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "Dev",
+              children: [
+                {
+                  guid: "bzBmk_______",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "Bugzilla",
+                  url: "https://bugzilla.mozilla.org/",
+                },
+                {
+                  guid: "wmBmk_______",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "Webmaker",
+                  url: "https://webmaker.org/",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "mozFolder___",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "Mozilla",
+              children: [
+                {
+                  guid: "nightlyBmk__",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "Nightly",
+                  url: "https://nightly.mozilla.org/",
+                },
+                {
+                  guid: "mdnBmk______",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "MDN",
+                  url: "https://developer.mozilla.org/",
+                },
+                {
+                  guid: "fxBmk_______",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 2,
+                  title: "Get Firefox!",
+                  url: "http://getfirefox.com/",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should move and reorder bookmarks to match remote"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_move_into_parent_sibling() {
+  // This test moves a bookmark that exists locally into a new folder that only
+  // exists remotely, and is a later sibling of the local parent. This ensures
+  // we set up the local structure before applying structure changes.
+  let buf = await openMirror("move_into_parent_sibling");
+
+  info("Set up mirror: Menu > A > B");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes: Menu > (A (B > C))");
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["folderAAAAAA", "folderCCCCCC"],
+    },
+    {
+      id: "folderAAAAAA",
+      parentid: "menu",
+      type: "folder",
+      title: "A",
+    },
+    {
+      id: "folderCCCCCC",
+      parentid: "menu",
+      type: "folder",
+      title: "C",
+      children: ["bookmarkBBBB"],
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "folderCCCCCC",
+      type: "bookmark",
+      title: "B",
+      bmkUri: "http://example.com/b",
+    },
+  ]);
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [],
+      deleted: [],
+    },
+    "Should not upload records for remote-only structure changes"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "folderCCCCCC",
+    "bookmarkBBBB",
+    "folderAAAAAA",
+    PlacesUtils.bookmarks.menuGuid,
+  ]);
+  observer.check([
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("folderCCCCCC"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        urlHref: "",
+        title: "C",
+        guid: "folderCCCCCC",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        oldIndex: 0,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkBBBB",
+        oldParentGuid: "folderAAAAAA",
+        newParentGuid: "folderCCCCCC",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/b",
+        isTagging: false,
+        title: "B",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+  ]);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "folderAAAAAA",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: "A",
+        },
+        {
+          guid: "folderCCCCCC",
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: "C",
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+          ],
+        },
+      ],
+    },
+    "Should set up local structure correctly"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_complex_move_with_additions() {
+  let mergeTelemetryCounts;
+  let buf = await openMirror("complex_move_with_additions", {
+    recordStepTelemetry(name, took, counts) {
+      if (name == "merge") {
+        mergeTelemetryCounts = counts;
+      }
+    },
+  });
+
+  info("Set up mirror: Menu > A > (B C)");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB", "bookmarkCCCC"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make local change: Menu > A > (B C D)");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkDDDD",
+    parentGuid: "folderAAAAAA",
+    title: "D (local)",
+    url: "http://example.com/d-local",
+  });
+
+  info("Make remote change: ((Menu > C) (Toolbar > A > (B E)))");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkCCCC"],
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "toolbar",
+        type: "folder",
+        title: "A",
+        children: ["bookmarkBBBB", "bookmarkEEEE"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["folderAAAAAA"],
+    "Should leave A with new remote structure unmerged"
+  );
+  deepEqual(
+    mergeTelemetryCounts,
+    [{ name: "items", count: 10 }],
+    "Should record telemetry with structure change counts"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkDDDD", "folderAAAAAA"],
+      deleted: [],
+    },
+    "Should upload new records for (A D)"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "bookmarkEEEE",
+    "folderAAAAAA",
+    "bookmarkCCCC",
+  ]);
+  observer.check([
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("bookmarkEEEE"),
+        parentId: localItemIds.get("folderAAAAAA"),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/e",
+        title: "E",
+        guid: "bookmarkEEEE",
+        parentGuid: "folderAAAAAA",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        oldIndex: 1,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkCCCC",
+        oldParentGuid: "folderAAAAAA",
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/c",
+        isTagging: false,
+        title: "C",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("folderAAAAAA"),
+        oldIndex: 0,
+        newIndex: 0,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        guid: "folderAAAAAA",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "",
+        isTagging: false,
+        title: "A",
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: 0,
+        lastVisitDate: null,
+      },
+    },
+  ]);
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              // We can guarantee child order (B E D), since we always walk remote
+              // children first, and the remote folder A record is newer than the
+              // local folder. If the local folder were newer, the order would be
+              // (D B E).
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "B",
+                  url: "http://example.com/b",
+                },
+                {
+                  guid: "bookmarkEEEE",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "E",
+                  url: "http://example.com/e",
+                },
+                {
+                  guid: "bookmarkDDDD",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 2,
+                  title: "D (local)",
+                  url: "http://example.com/d-local",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should take remote order and preserve local children"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_reorder_and_insert() {
+  let buf = await openMirror("reorder_and_insert");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+      },
+      {
+        guid: "bookmarkCCCC",
+        url: "http://example.com/c",
+        title: "C",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bookmarkDDDD",
+        url: "http://example.com/d",
+        title: "D",
+      },
+      {
+        guid: "bookmarkEEEE",
+        url: "http://example.com/e",
+        title: "E",
+      },
+      {
+        guid: "bookmarkFFFF",
+        url: "http://example.com/f",
+        title: "F",
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkBBBB", "bookmarkCCCC"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkDDDD", "bookmarkEEEE", "bookmarkFFFF"],
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let now = Date.now();
+
+  info("Make local changes: Reorder Menu, Toolbar > (G H)");
+  await PlacesUtils.bookmarks.reorder(PlacesUtils.bookmarks.menuGuid, [
+    "bookmarkCCCC",
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]);
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bookmarkGGGG",
+        url: "http://example.com/g",
+        title: "G",
+        dateAdded: new Date(now),
+        lastModified: new Date(now),
+      },
+      {
+        guid: "bookmarkHHHH",
+        url: "http://example.com/h",
+        title: "H",
+        dateAdded: new Date(now),
+        lastModified: new Date(now),
+      },
+    ],
+  });
+
+  info("Make remote changes: Reorder Toolbar, Menu > (I J)");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        // The server has a newer toolbar, so we should use the remote order (F D E)
+        // as the base, then append (G H).
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkFFFF", "bookmarkDDDD", "bookmarkEEEE"],
+        modified: now / 1000 + 5,
+      },
+      {
+        // The server has an older menu, so we should use the local order (C A B)
+        // as the base, then append (I J).
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkAAAA",
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkIIII",
+          "bookmarkJJJJ",
+        ],
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkIIII",
+        parentid: "menu",
+        type: "bookmark",
+        title: "I",
+        bmkUri: "http://example.com/i",
+      },
+      {
+        id: "bookmarkJJJJ",
+        parentid: "menu",
+        type: "bookmark",
+        title: "J",
+        bmkUri: "http://example.com/j",
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    remoteTimeSeconds: now / 1000,
+    localTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.menuGuid, PlacesUtils.bookmarks.toolbarGuid],
+    "Should leave roots with new remote structure unmerged"
+  );
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkGGGG", "bookmarkHHHH", "menu", "toolbar"],
+      deleted: [],
+    },
+    "Should upload records for merged and new local items"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              url: "http://example.com/c",
+              title: "C",
+            },
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              url: "http://example.com/a",
+              title: "A",
+            },
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 2,
+              url: "http://example.com/b",
+              title: "B",
+            },
+            {
+              guid: "bookmarkIIII",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 3,
+              url: "http://example.com/i",
+              title: "I",
+            },
+            {
+              guid: "bookmarkJJJJ",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 4,
+              url: "http://example.com/j",
+              title: "J",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkFFFF",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              url: "http://example.com/f",
+              title: "F",
+            },
+            {
+              guid: "bookmarkDDDD",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              url: "http://example.com/d",
+              title: "D",
+            },
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 2,
+              url: "http://example.com/e",
+              title: "E",
+            },
+            {
+              guid: "bookmarkGGGG",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 3,
+              url: "http://example.com/g",
+              title: "G",
+            },
+            {
+              guid: "bookmarkHHHH",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 4,
+              url: "http://example.com/h",
+              title: "H",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should use timestamps to decide base folder order"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_newer_remote_moves() {
+  let now = Date.now();
+  let buf = await openMirror("newer_remote_moves");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+      {
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+            dateAdded: new Date(now - 5000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        guid: "folderDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bookmarkEEEE",
+        url: "http://example.com/e",
+        title: "E",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+      {
+        guid: "folderFFFFFF",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "F",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            guid: "bookmarkGGGG",
+            url: "http://example.com/g",
+            title: "G",
+            dateAdded: new Date(now - 5000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        guid: "folderHHHHHH",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "H",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "folderBBBBBB", "folderDDDDDD"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkEEEE", "folderFFFFFF", "folderHHHHHH"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "toolbar",
+        type: "folder",
+        title: "F",
+        children: ["bookmarkGGGG"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkGGGG",
+        parentid: "folderFFFFFF",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderHHHHHH",
+        parentid: "toolbar",
+        type: "folder",
+        title: "H",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info(
+    "Make local changes: Unfiled > A, Mobile > B; Toolbar > (H F E); D > C; H > G"
+  );
+  let localMoves = [
+    {
+      guid: "bookmarkAAAA",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      guid: "folderBBBBBB",
+      parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    },
+    {
+      guid: "bookmarkCCCC",
+      parentGuid: "folderDDDDDD",
+    },
+    {
+      guid: "bookmarkGGGG",
+      parentGuid: "folderHHHHHH",
+    },
+  ];
+  for (let { guid, parentGuid } of localMoves) {
+    await PlacesUtils.bookmarks.update({
+      guid,
+      parentGuid,
+      index: 0,
+      lastModified: new Date(now - 2500),
+    });
+  }
+  await PlacesUtils.bookmarks.reorder(
+    PlacesUtils.bookmarks.toolbarGuid,
+    ["folderHHHHHH", "folderFFFFFF", "bookmarkEEEE"],
+    { lastModified: new Date(now - 2500) }
+  );
+
+  info(
+    "Make remote changes: Mobile > A, Unfiled > B; Toolbar > (F E H); D > G; H > C"
+  );
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderDDDDDD"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        // This is similar to H > C, explained below, except we'll always reupload
+        // the mobile root, because we always prefer the local state for roots.
+        id: "bookmarkAAAA",
+        parentid: "mobile",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: ["folderBBBBBB"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "unfiled",
+        type: "folder",
+        title: "B",
+        children: [],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["folderFFFFFF", "bookmarkEEEE", "folderHHHHHH"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "folderHHHHHH",
+        parentid: "toolbar",
+        type: "folder",
+        title: "H",
+        children: ["bookmarkCCCC"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        // Reparenting an item uploads records for the item and its parent.
+        // The merger would still work if we only marked H as unmerged; we'd
+        // then use the remote state for H, and local state for C. Since C was
+        // changed locally, we'll reupload it, even though it didn't actually
+        // change.
+        id: "bookmarkCCCC",
+        parentid: "folderHHHHHH",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkGGGG"],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        dateAdded: now - 5000,
+        modified: now / 1000,
+        children: ["bookmarkGGGG"],
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "toolbar",
+        type: "folder",
+        title: "F",
+        children: [],
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+      {
+        // Same as C above.
+        id: "bookmarkGGGG",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+        dateAdded: now - 5000,
+        modified: now / 1000,
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    localTimeSeconds: now / 1000,
+    remoteTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.mobileGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave roots with new remote structure unmerged"
+  );
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.mobileGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      // We took the remote structure for the roots, but they're still flagged as
+      // changed locally. Since we always use the local state for roots
+      // (bug 1472241), and can't distinguish between value and structure changes
+      // in Places (see the comment for F below), we'll reupload them.
+      menu: {
+        tombstone: false,
+        counter: 2,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          children: ["folderDDDDDD"],
+          title: BookmarksMenuTitle,
+        },
+      },
+      mobile: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "mobile",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.mobileGuid),
+          children: ["bookmarkAAAA"],
+          title: MobileBookmarksTitle,
+        },
+      },
+      unfiled: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "unfiled",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+          children: ["folderBBBBBB"],
+          title: UnfiledBookmarksTitle,
+        },
+      },
+      toolbar: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "toolbar",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.toolbarGuid),
+          children: ["folderFFFFFF", "bookmarkEEEE", "folderHHHHHH"],
+          title: BookmarksToolbarTitle,
+        },
+      },
+    },
+    "Should only reupload local roots"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderDDDDDD",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "D",
+              children: [
+                {
+                  guid: "bookmarkGGGG",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "G",
+                  url: "http://example.com/g",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "folderFFFFFF",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "F",
+            },
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "E",
+              url: "http://example.com/e",
+            },
+            {
+              guid: "folderHHHHHH",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 2,
+              title: "H",
+              children: [
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "C",
+                  url: "http://example.com/c",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "folderBBBBBB",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "B",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+      ],
+    },
+    "Should use newer remote parents and order"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_newer_local_moves() {
+  let now = Date.now();
+  let buf = await openMirror("newer_local_moves");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+      {
+        guid: "folderBBBBBB",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "B",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+            dateAdded: new Date(now - 5000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        guid: "folderDDDDDD",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "D",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bookmarkEEEE",
+        url: "http://example.com/e",
+        title: "E",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+      {
+        guid: "folderFFFFFF",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "F",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+        children: [
+          {
+            guid: "bookmarkGGGG",
+            url: "http://example.com/g",
+            title: "G",
+            dateAdded: new Date(now - 5000),
+            lastModified: new Date(now - 5000),
+          },
+        ],
+      },
+      {
+        guid: "folderHHHHHH",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "H",
+        dateAdded: new Date(now - 5000),
+        lastModified: new Date(now - 5000),
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "folderBBBBBB", "folderDDDDDD"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "menu",
+        type: "folder",
+        title: "B",
+        children: ["bookmarkCCCC"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderBBBBBB",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkEEEE", "folderFFFFFF", "folderHHHHHH"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "toolbar",
+        type: "folder",
+        title: "F",
+        children: ["bookmarkGGGG"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "bookmarkGGGG",
+        parentid: "folderFFFFFF",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+      {
+        id: "folderHHHHHH",
+        parentid: "toolbar",
+        type: "folder",
+        title: "H",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 5,
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info(
+    "Make local changes: Unfiled > A, Mobile > B; Toolbar > (H F E); D > C; H > G"
+  );
+  let localMoves = [
+    {
+      guid: "bookmarkAAAA",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    },
+    {
+      guid: "folderBBBBBB",
+      parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    },
+    {
+      guid: "bookmarkCCCC",
+      parentGuid: "folderDDDDDD",
+    },
+    {
+      guid: "bookmarkGGGG",
+      parentGuid: "folderHHHHHH",
+    },
+  ];
+  for (let { guid, parentGuid } of localMoves) {
+    await PlacesUtils.bookmarks.update({
+      guid,
+      parentGuid,
+      index: 0,
+      lastModified: new Date(now),
+    });
+  }
+  await PlacesUtils.bookmarks.reorder(
+    PlacesUtils.bookmarks.toolbarGuid,
+    ["folderHHHHHH", "folderFFFFFF", "bookmarkEEEE"],
+    { lastModified: new Date(now) }
+  );
+
+  info(
+    "Make remote changes: Mobile > A, Unfiled > B; Toolbar > (F E H); D > G; H > C"
+  );
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderDDDDDD"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "mobile",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "mobile",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "unfiled",
+        parentid: "places",
+        type: "folder",
+        children: ["folderBBBBBB"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "folderBBBBBB",
+        parentid: "unfiled",
+        type: "folder",
+        title: "B",
+        children: [],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["folderFFFFFF", "bookmarkEEEE", "folderHHHHHH"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "folderHHHHHH",
+        parentid: "toolbar",
+        type: "folder",
+        title: "H",
+        children: ["bookmarkCCCC"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderHHHHHH",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "folderDDDDDD",
+        parentid: "menu",
+        type: "folder",
+        title: "D",
+        children: ["bookmarkGGGG"],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "toolbar",
+        type: "folder",
+        title: "F",
+        children: [],
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+      {
+        id: "bookmarkGGGG",
+        parentid: "folderDDDDDD",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+        dateAdded: now - 5000,
+        modified: now / 1000 - 2.5,
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    localTimeSeconds: now / 1000,
+    remoteTimeSeconds: now / 1000,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      "bookmarkAAAA",
+      "bookmarkCCCC",
+      "bookmarkGGGG",
+      "folderBBBBBB",
+      "folderDDDDDD",
+      "folderFFFFFF",
+      "folderHHHHHH",
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.mobileGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave items with new remote structure unmerged"
+  );
+  let datesAdded = await promiseManyDatesAdded([
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.mobileGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+  ]);
+  deepEqual(
+    changesToUpload,
+    {
+      // Reupload roots with new children.
+      menu: {
+        tombstone: false,
+        counter: 2,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.menuGuid),
+          children: ["folderDDDDDD"],
+          title: BookmarksMenuTitle,
+        },
+      },
+      mobile: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "mobile",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.mobileGuid),
+          children: ["folderBBBBBB"],
+          title: MobileBookmarksTitle,
+        },
+      },
+      unfiled: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "unfiled",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.unfiledGuid),
+          children: ["bookmarkAAAA"],
+          title: UnfiledBookmarksTitle,
+        },
+      },
+      toolbar: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "toolbar",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: datesAdded.get(PlacesUtils.bookmarks.toolbarGuid),
+          children: ["folderHHHHHH", "folderFFFFFF", "bookmarkEEEE"],
+          title: BookmarksToolbarTitle,
+        },
+      },
+      // G moved to H from F, so F and H have new children, and we need
+      // to upload G for the new `parentid`.
+      folderFFFFFF: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderFFFFFF",
+          type: "folder",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: now - 5000,
+          children: [],
+          title: "F",
+        },
+      },
+      folderHHHHHH: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderHHHHHH",
+          type: "folder",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: now - 5000,
+          children: ["bookmarkGGGG"],
+          title: "H",
+        },
+      },
+      bookmarkGGGG: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkGGGG",
+          type: "bookmark",
+          parentid: "folderHHHHHH",
+          hasDupe: true,
+          parentName: "H",
+          dateAdded: now - 5000,
+          bmkUri: "http://example.com/g",
+          title: "G",
+        },
+      },
+      // C moved to D, so we need to reupload D (for `children`) and C
+      // (for `parentid`).
+      folderDDDDDD: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderDDDDDD",
+          type: "folder",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: now - 5000,
+          children: ["bookmarkCCCC"],
+          title: "D",
+        },
+      },
+      bookmarkCCCC: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkCCCC",
+          type: "bookmark",
+          parentid: "folderDDDDDD",
+          hasDupe: true,
+          parentName: "D",
+          dateAdded: now - 5000,
+          bmkUri: "http://example.com/c",
+          title: "C",
+        },
+      },
+      // Reupload A with the new `parentid`. B moved to mobile *and* has
+      // new children` so we should upload it, anyway.
+      bookmarkAAAA: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkAAAA",
+          type: "bookmark",
+          parentid: "unfiled",
+          hasDupe: true,
+          parentName: UnfiledBookmarksTitle,
+          dateAdded: now - 5000,
+          bmkUri: "http://example.com/a",
+          title: "A",
+        },
+      },
+      folderBBBBBB: {
+        tombstone: false,
+        counter: 2,
+        synced: false,
+        cleartext: {
+          id: "folderBBBBBB",
+          type: "folder",
+          parentid: "mobile",
+          hasDupe: true,
+          parentName: MobileBookmarksTitle,
+          dateAdded: now - 5000,
+          children: [],
+          title: "B",
+        },
+      },
+    },
+    "Should reupload new local structure"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderDDDDDD",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "D",
+              children: [
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "C",
+                  url: "http://example.com/c",
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "folderHHHHHH",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "H",
+              children: [
+                {
+                  guid: "bookmarkGGGG",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "G",
+                  url: "http://example.com/g",
+                },
+              ],
+            },
+            {
+              guid: "folderFFFFFF",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 1,
+              title: "F",
+            },
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 2,
+              title: "E",
+              url: "http://example.com/e",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A",
+              url: "http://example.com/a",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+          children: [
+            {
+              guid: "folderBBBBBB",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "B",
+            },
+          ],
+        },
+      ],
+    },
+    "Should use newer local parents and order"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_unchanged_newer_changed_older() {
+  let buf = await openMirror("unchanged_newer_changed_older");
+  let modified = new Date(Date.now() - 5000);
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    dateAdded: new Date(modified.getTime() - 5000),
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    dateAdded: new Date(modified.getTime() - 5000),
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        dateAdded: new Date(modified.getTime() - 5000),
+        lastModified: modified,
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+        dateAdded: new Date(modified.getTime() - 5000),
+        lastModified: modified,
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "folderCCCCCC",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "C",
+        dateAdded: new Date(modified.getTime() - 5000),
+        lastModified: modified,
+      },
+      {
+        guid: "bookmarkDDDD",
+        url: "http://example.com/d",
+        title: "D",
+        dateAdded: new Date(modified.getTime() - 5000),
+        lastModified: modified,
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "bookmarkBBBB"],
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["folderCCCCCC", "bookmarkDDDD"],
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+      {
+        id: "folderCCCCCC",
+        parentid: "toolbar",
+        type: "folder",
+        title: "C",
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000,
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  // Even though the local menu is newer (local = 5s, remote = 9s; adding E
+  // updated the modified times of A and the menu), it's not *changed* locally,
+  // so we should merge remote children first.
+  info("Add A > E locally with newer time; delete A remotely with older time");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkEEEE",
+    parentGuid: "folderAAAAAA",
+    url: "http://example.com/e",
+    title: "E",
+    index: 0,
+    dateAdded: new Date(modified.getTime() + 5000),
+    lastModified: new Date(modified.getTime() + 5000),
+  });
+  await storeRecords(buf, [
+    {
+      id: "menu",
+      parentid: "places",
+      type: "folder",
+      children: ["bookmarkBBBB"],
+      dateAdded: modified.getTime() - 5000,
+      modified: modified.getTime() / 1000 + 1,
+    },
+    {
+      id: "folderAAAAAA",
+      deleted: true,
+    },
+  ]);
+
+  // Even though the remote toolbar is newer (local = 15s, remote = 10s), it's
+  // not changed remotely, so we should merge local children first.
+  info("Add C > F remotely with newer time; delete C locally with older time");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "folderCCCCCC",
+        parentid: "toolbar",
+        type: "folder",
+        title: "C",
+        children: ["bookmarkFFFF"],
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000 + 5,
+      },
+      {
+        id: "bookmarkFFFF",
+        parentid: "folderCCCCCC",
+        type: "bookmark",
+        title: "F",
+        bmkUri: "http://example.com/f",
+        dateAdded: modified.getTime() - 5000,
+        modified: modified.getTime() / 1000 + 5,
+      },
+    ])
+  );
+  await PlacesUtils.bookmarks.remove("folderCCCCCC");
+  await PlacesUtils.bookmarks.update({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    lastModified: new Date(modified.getTime() - 5000),
+    // Use `SOURCES.SYNC` to avoid bumping the change counter and flagging the
+    // local toolbar as modified.
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+  });
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply({
+    localTimeSeconds: modified.getTime() / 1000 + 10,
+    remoteTimeSeconds: modified.getTime() / 1000 + 10,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkFFFF", "folderCCCCCC", PlacesUtils.bookmarks.menuGuid],
+    "Should leave deleted C; F and menu with new remote structure unmerged"
+  );
+
+  deepEqual(
+    changesToUpload,
+    {
+      menu: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "menu",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: modified.getTime() - 5000,
+          children: ["bookmarkBBBB", "bookmarkEEEE"],
+          title: BookmarksMenuTitle,
+        },
+      },
+      toolbar: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "toolbar",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: modified.getTime() - 5000,
+          children: ["bookmarkDDDD", "bookmarkFFFF"],
+          title: BookmarksToolbarTitle,
+        },
+      },
+      // Upload E and F with new `parentid`.
+      bookmarkEEEE: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkEEEE",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: modified.getTime() + 5000,
+          bmkUri: "http://example.com/e",
+          title: "E",
+        },
+      },
+      bookmarkFFFF: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkFFFF",
+          type: "bookmark",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: modified.getTime() - 5000,
+          bmkUri: "http://example.com/f",
+          title: "F",
+        },
+      },
+      folderCCCCCC: {
+        tombstone: true,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "folderCCCCCC",
+          deleted: true,
+        },
+      },
+    },
+    "Should reupload menu, toolbar, E, F with new structure; tombstone for C"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B",
+              url: "http://example.com/b",
+            },
+            {
+              guid: "bookmarkEEEE",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "E",
+              url: "http://example.com/e",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkDDDD",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "D",
+              url: "http://example.com/d",
+            },
+            {
+              guid: "bookmarkFFFF",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 1,
+              title: "F",
+              url: "http://example.com/f",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should merge children of changed side first, even if they're older"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones.map(({ guid }) => guid),
+    ["folderCCCCCC"],
+    "Should store local tombstone for C"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_unknown_fields.js b/toolkit/components/places/tests/sync/test_bookmark_unknown_fields.js
new file mode 100644
index 0000000000..e5e1d4e078
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_unknown_fields.js
@@ -0,0 +1,206 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_bookmark_unknown_fields() {
+  let buf = await openMirror("unknown_fields");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+        unknownStr: "an unknown field",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "New Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+        unknownStr: "a new unknown field",
+      },
+    ],
+    { needsMerge: true }
+  );
+
+  let controller = new AbortController();
+  const wasMerged = await buf.merge(controller.signal);
+  Assert.ok(wasMerged);
+
+  let itemRows = await buf.db.execute(`SELECT guid, unknownFields FROM items`);
+
+  let updatedBookmark = itemRows.find(
+    row => row.getResultByName("guid") == "mozBmk______"
+  );
+  deepEqual(JSON.parse(updatedBookmark.getResultByName("unknownFields")), {
+    unknownStr: "a new unknown field",
+  });
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_changes_unknown_fields_all_types() {
+  let buf = await openMirror("unknown_fields_all");
+
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        title: "menu",
+        children: ["bookmarkAAAA", "separatorAAA", "queryAAAAAAA"],
+        unknownFolderField: "an unknown folder field",
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla2",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+        unknownStrField: "an unknown bookmark field",
+        unknownStrObj: { newField: "unknown pt deux" },
+      },
+      {
+        id: "separatorAAA",
+        parentid: "menu",
+        type: "separator",
+        unknownSepField: "an unknown separator field",
+      },
+      {
+        id: "queryAAAAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "a query",
+        bmkUri: "place:foo",
+        unknownQueryField: "an unknown query field",
+      },
+    ],
+    { needsMerge: true }
+  );
+
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  let changesToUpload = await buf.apply();
+  // Should be no local changes needing to be uploaded
+  deepEqual(changesToUpload, {});
+
+  // Make updates to all the type of bookmarks
+  await PlacesUtils.bookmarks.update({
+    guid: "menu________",
+    title: "updated menu",
+  });
+  await PlacesUtils.bookmarks.update({
+    guid: "bookmarkAAAA",
+    title: "Mozilla3",
+  });
+  await PlacesUtils.bookmarks.update({ guid: "separatorAAA", index: 2 });
+  await PlacesUtils.bookmarks.update({
+    guid: "queryAAAAAAA",
+    title: "an updated query",
+  });
+
+  // We should now have a bunch of changes to upload
+  changesToUpload = await buf.apply();
+  const { menu, bookmarkAAAA, separatorAAA, queryAAAAAAA } = changesToUpload;
+
+  // Validate we have the updated title as well as the unknown fields
+  Assert.equal(menu.cleartext.title, "updated menu");
+  Assert.equal(menu.cleartext.unknownFolderField, "an unknown folder field");
+
+  // Test bookmark unknown fields
+  Assert.equal(bookmarkAAAA.cleartext.title, "Mozilla3");
+  Assert.equal(
+    bookmarkAAAA.cleartext.unknownStrField,
+    "an unknown bookmark field"
+  );
+  deepEqual(bookmarkAAAA.cleartext.unknownStrObj, {
+    newField: "unknown pt deux",
+  });
+
+  // Test separator unknown fields
+  Assert.equal(
+    separatorAAA.cleartext.unknownSepField,
+    "an unknown separator field"
+  );
+
+  // Test query unknown fields
+  Assert.equal(queryAAAAAAA.cleartext.title, "an updated query");
+  Assert.equal(
+    queryAAAAAAA.cleartext.unknownQueryField,
+    "an unknown query field"
+  );
+
+  let itemRows = await buf.db.execute(`SELECT guid, unknownFields FROM items`);
+
+  // Test bookmark correctly JSON'd in the mirror
+  let remoteBookmark = itemRows.find(
+    row => row.getResultByName("guid") == "bookmarkAAAA"
+  );
+  deepEqual(JSON.parse(remoteBookmark.getResultByName("unknownFields")), {
+    unknownStrField: "an unknown bookmark field",
+    unknownStrObj: { newField: "unknown pt deux" },
+  });
+
+  // Test folder correctly JSON'd in the mirror
+  let remoteFolder = itemRows.find(
+    row => row.getResultByName("guid") == "menu________"
+  );
+  deepEqual(JSON.parse(remoteFolder.getResultByName("unknownFields")), {
+    unknownFolderField: "an unknown folder field",
+  });
+  // Test query correctly JSON'd in the mirror
+  let remoteQuery = itemRows.find(
+    row => row.getResultByName("guid") == "queryAAAAAAA"
+  );
+  deepEqual(JSON.parse(remoteQuery.getResultByName("unknownFields")), {
+    unknownQueryField: "an unknown query field",
+  });
+  // Test separator correctly JSON'd in the mirror
+  let remoteSeparator = itemRows.find(
+    row => row.getResultByName("guid") == "separatorAAA"
+  );
+  deepEqual(JSON.parse(remoteSeparator.getResultByName("unknownFields")), {
+    unknownSepField: "an unknown separator field",
+  });
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_bookmark_value_changes.js b/toolkit/components/places/tests/sync/test_bookmark_value_changes.js
new file mode 100644
index 0000000000..be20a59c68
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_bookmark_value_changes.js
@@ -0,0 +1,2639 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_value_combo() {
+  let buf = await openMirror("value_combo");
+  let now = Date.now();
+
+  info("Set up mirror with existing bookmark to update");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "mozBmk______",
+        url: "https://mozilla.org",
+        title: "Mozilla",
+        tags: ["moz", "dot", "org"],
+        dateAdded: new Date(now),
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["mozBmk______"],
+      },
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla",
+        bmkUri: "https://mozilla.org",
+        tags: ["moz", "dot", "org"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Insert new local bookmark to upload");
+  let [bzBmk] = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        guid: "bzBmk_______",
+        url: "https://bugzilla.mozilla.org",
+        title: "Bugzilla",
+        tags: ["new", "tag"],
+      },
+    ],
+  });
+
+  info("Insert remote bookmarks and folder to apply");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "mozBmk______",
+        parentid: "menu",
+        type: "bookmark",
+        title: "Mozilla home page",
+        bmkUri: "https://mozilla.org",
+        tags: ["browsers"],
+      },
+      {
+        id: "toolbar",
+        parentid: "places",
+        type: "folder",
+        children: ["fxBmk_______", "tFolder_____"],
+      },
+      {
+        id: "fxBmk_______",
+        parentid: "toolbar",
+        type: "bookmark",
+        title: "Get Firefox",
+        bmkUri: "http://getfirefox.com",
+        tags: ["taggy", "browsers"],
+        dateAdded: now,
+      },
+      {
+        id: "tFolder_____",
+        parentid: "toolbar",
+        type: "folder",
+        title: "Mail",
+        children: ["tbBmk_______"],
+        dateAdded: now,
+      },
+      {
+        id: "tbBmk_______",
+        parentid: "tFolder_____",
+        type: "bookmark",
+        title: "Get Thunderbird",
+        bmkUri: "http://getthunderbird.com",
+        keyword: "tb",
+        dateAdded: now,
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications({
+    skipTags: true,
+    ignoreDates: false,
+  });
+  let localTimeSeconds = Math.floor(now / 1000);
+  let changesToUpload = await buf.apply({
+    localTimeSeconds,
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [PlacesUtils.bookmarks.toolbarGuid],
+    "Should leave toolbar with new remote structure unmerged"
+  );
+
+  let menuInfo = await PlacesUtils.bookmarks.fetch(
+    PlacesUtils.bookmarks.menuGuid
+  );
+  deepEqual(
+    changesToUpload,
+    {
+      bzBmk_______: {
+        tombstone: false,
+        counter: 3,
+        synced: false,
+        cleartext: {
+          id: "bzBmk_______",
+          type: "bookmark",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: bzBmk.dateAdded.getTime(),
+          bmkUri: "https://bugzilla.mozilla.org/",
+          title: "Bugzilla",
+          tags: ["new", "tag"],
+        },
+      },
+      toolbar: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "toolbar",
+          type: "folder",
+          parentid: "places",
+          hasDupe: true,
+          parentName: "",
+          dateAdded: menuInfo.dateAdded.getTime(),
+          title: BookmarksToolbarTitle,
+          children: ["fxBmk_______", "tFolder_____", "bzBmk_______"],
+        },
+      },
+    },
+    "Should upload new local bookmarks and parents"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "fxBmk_______",
+    "tFolder_____",
+    "tbBmk_______",
+    "bzBmk_______",
+    "mozBmk______",
+    PlacesUtils.bookmarks.toolbarGuid,
+  ]);
+
+  observer.check([
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("fxBmk_______"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.toolbarGuid),
+        index: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://getfirefox.com/",
+        title: "Get Firefox",
+        guid: "fxBmk_______",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        dateAdded: now,
+        tags: "browsers,taggy",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("tFolder_____"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.toolbarGuid),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        urlHref: "",
+        title: "Mail",
+        guid: "tFolder_____",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        dateAdded: now,
+        tags: "",
+        frecency: 0,
+        hidden: false,
+        visitCount: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("tbBmk_______"),
+        parentId: localItemIds.get("tFolder_____"),
+        index: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://getthunderbird.com/",
+        title: "Get Thunderbird",
+        guid: "tbBmk_______",
+        parentGuid: "tFolder_____",
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        dateAdded: now,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bzBmk_______"),
+        oldIndex: 0,
+        newIndex: 2,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bzBmk_______",
+        oldParentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        newParentGuid: PlacesUtils.bookmarks.toolbarGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "https://bugzilla.mozilla.org/",
+        isTagging: false,
+        title: "Bugzilla",
+        tags: "new,tag",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: bzBmk.dateAdded.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("mozBmk______"),
+        title: "Mozilla home page",
+        guid: "mozBmk______",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+  ]);
+
+  let fxBmk = await PlacesUtils.bookmarks.fetch("fxBmk_______");
+  ok(fxBmk, "New Firefox bookmark should exist");
+  equal(
+    fxBmk.parentGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    "Should add Firefox bookmark to toolbar"
+  );
+  let fxTags = PlacesUtils.tagging.getTagsForURI(
+    Services.io.newURI("http://getfirefox.com")
+  );
+  deepEqual(fxTags, ["browsers", "taggy"], "Should tag new Firefox bookmark");
+
+  let folder = await PlacesUtils.bookmarks.fetch("tFolder_____");
+  ok(folder, "New folder should exist");
+  equal(
+    folder.parentGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    "Should add new folder to toolbar"
+  );
+
+  let tbBmk = await PlacesUtils.bookmarks.fetch("tbBmk_______");
+  ok(tbBmk, "Should insert Thunderbird child bookmark");
+  equal(
+    tbBmk.parentGuid,
+    folder.guid,
+    "Should add Thunderbird bookmark to new folder"
+  );
+  let keywordInfo = await PlacesUtils.keywords.fetch("tb");
+  equal(
+    keywordInfo.url.href,
+    "http://getthunderbird.com/",
+    "Should set keyword for Thunderbird bookmark"
+  );
+
+  let updatedBmk = await PlacesUtils.bookmarks.fetch("mozBmk______");
+  equal(
+    updatedBmk.title,
+    "Mozilla home page",
+    "Should rename Mozilla bookmark"
+  );
+  equal(
+    updatedBmk.parentGuid,
+    PlacesUtils.bookmarks.menuGuid,
+    "Should not move Mozilla bookmark"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_value_only_changes() {
+  let buf = await openMirror("value_only_changes");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "folderAAAAAA",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "A",
+        children: [
+          {
+            guid: "bookmarkBBBB",
+            url: "http://example.com/b",
+            title: "B",
+          },
+          {
+            guid: "bookmarkCCCC",
+            url: "http://example.com/c",
+            title: "C",
+          },
+          {
+            guid: "folderJJJJJJ",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "J",
+            children: [
+              {
+                guid: "bookmarkKKKK",
+                url: "http://example.com/k",
+                title: "K",
+              },
+            ],
+          },
+          {
+            guid: "bookmarkDDDD",
+            url: "http://example.com/d",
+            title: "D",
+          },
+          {
+            guid: "bookmarkEEEE",
+            url: "http://example.com/e",
+            title: "E",
+          },
+        ],
+      },
+      {
+        guid: "folderFFFFFF",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        title: "F",
+        children: [
+          {
+            guid: "bookmarkGGGG",
+            url: "http://example.com/g",
+            title: "G",
+          },
+          {
+            guid: "folderHHHHHH",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            title: "H",
+            children: [
+              {
+                guid: "bookmarkIIII",
+                url: "http://example.com/i",
+                title: "I",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["folderAAAAAA", "folderFFFFFF"],
+      },
+      {
+        id: "folderAAAAAA",
+        parentid: "menu",
+        type: "folder",
+        title: "A",
+        children: [
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "folderJJJJJJ",
+          "bookmarkDDDD",
+          "bookmarkEEEE",
+        ],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "folderJJJJJJ",
+        parentid: "folderAAAAAA",
+        type: "folder",
+        title: "J",
+        children: ["bookmarkKKKK"],
+      },
+      {
+        id: "bookmarkKKKK",
+        parentid: "folderJJJJJJ",
+        type: "bookmark",
+        title: "K",
+        bmkUri: "http://example.com/k",
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "menu",
+        type: "folder",
+        title: "F",
+        children: ["bookmarkGGGG", "folderHHHHHH"],
+      },
+      {
+        id: "bookmarkGGGG",
+        parentid: "folderFFFFFF",
+        type: "bookmark",
+        title: "G",
+        bmkUri: "http://example.com/g",
+      },
+      {
+        id: "folderHHHHHH",
+        parentid: "folderFFFFFF",
+        type: "folder",
+        title: "H",
+        children: ["bookmarkIIII"],
+      },
+      {
+        id: "bookmarkIIII",
+        parentid: "folderHHHHHH",
+        type: "bookmark",
+        title: "I",
+        bmkUri: "http://example.com/i",
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkCCCC",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "C (remote)",
+        bmkUri: "http://example.com/c-remote",
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "folderAAAAAA",
+        type: "bookmark",
+        title: "E (remote)",
+        bmkUri: "http://example.com/e-remote",
+      },
+      {
+        id: "bookmarkIIII",
+        parentid: "folderHHHHHH",
+        type: "bookmark",
+        title: "I (remote)",
+        bmkUri: "http://example.com/i-remote",
+      },
+      {
+        id: "folderFFFFFF",
+        parentid: "menu",
+        type: "folder",
+        title: "F (remote)",
+        children: ["bookmarkGGGG", "folderHHHHHH"],
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: [],
+      deleted: [],
+    },
+    "Should not upload records for remote-only value changes"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "folderAAAAAA",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 0,
+              title: "A",
+              children: [
+                {
+                  guid: "bookmarkBBBB",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "B",
+                  url: "http://example.com/b",
+                },
+                {
+                  guid: "bookmarkCCCC",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 1,
+                  title: "C (remote)",
+                  url: "http://example.com/c-remote",
+                },
+                {
+                  guid: "folderJJJJJJ",
+                  type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                  index: 2,
+                  title: "J",
+                  children: [
+                    {
+                      guid: "bookmarkKKKK",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 0,
+                      title: "K",
+                      url: "http://example.com/k",
+                    },
+                  ],
+                },
+                {
+                  guid: "bookmarkDDDD",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 3,
+                  title: "D",
+                  url: "http://example.com/d",
+                },
+                {
+                  guid: "bookmarkEEEE",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 4,
+                  title: "E (remote)",
+                  url: "http://example.com/e-remote",
+                },
+              ],
+            },
+            {
+              guid: "folderFFFFFF",
+              type: PlacesUtils.bookmarks.TYPE_FOLDER,
+              index: 1,
+              title: "F (remote)",
+              children: [
+                {
+                  guid: "bookmarkGGGG",
+                  type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                  index: 0,
+                  title: "G",
+                  url: "http://example.com/g",
+                },
+                {
+                  guid: "folderHHHHHH",
+                  type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                  index: 1,
+                  title: "H",
+                  children: [
+                    {
+                      guid: "bookmarkIIII",
+                      type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+                      index: 0,
+                      title: "I (remote)",
+                      url: "http://example.com/i-remote",
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should not change structure for value-only changes"
+  );
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_conflicting_keywords() {
+  let buf = await openMirror("conflicting_keywords");
+  let dateAdded = new Date();
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+        keyword: "one",
+        dateAdded,
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        keyword: "one",
+        dateAdded: dateAdded.getTime(),
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  {
+    let entryByKeyword = await PlacesUtils.keywords.fetch("one");
+    equal(
+      entryByKeyword.url.href,
+      "http://example.com/a",
+      "Should return new keyword entry by URL"
+    );
+    let entryByURL = await PlacesUtils.keywords.fetch({
+      url: "http://example.com/a",
+    });
+    equal(entryByURL.keyword, "one", "Should return new entry by keyword");
+  }
+
+  info("Insert new bookmark with same URL and different keyword");
+  {
+    await storeRecords(
+      buf,
+      shuffle([
+        {
+          id: "toolbar",
+          parentid: "places",
+          type: "folder",
+          children: ["bookmarkAAA1"],
+        },
+        {
+          id: "bookmarkAAA1",
+          parentid: "toolbar",
+          type: "bookmark",
+          title: "A1",
+          bmkUri: "http://example.com/a",
+          keyword: "two",
+          dateAdded: dateAdded.getTime(),
+        },
+      ])
+    );
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["bookmarkAAA1"],
+      "Should leave A1 with conflicting keyword unmerged"
+    );
+    deepEqual(
+      changesToUpload,
+      {
+        bookmarkAAAA: {
+          tombstone: false,
+          counter: 1,
+          synced: false,
+          cleartext: {
+            id: "bookmarkAAAA",
+            type: "bookmark",
+            parentid: "menu",
+            hasDupe: true,
+            parentName: BookmarksMenuTitle,
+            dateAdded: dateAdded.getTime(),
+            bmkUri: "http://example.com/a",
+            title: "A",
+            keyword: "two",
+          },
+        },
+        bookmarkAAA1: {
+          tombstone: false,
+          counter: 1,
+          synced: false,
+          cleartext: {
+            id: "bookmarkAAA1",
+            type: "bookmark",
+            parentid: "toolbar",
+            hasDupe: true,
+            parentName: BookmarksToolbarTitle,
+            dateAdded: dateAdded.getTime(),
+            bmkUri: "http://example.com/a",
+            title: "A1",
+            keyword: "two",
+          },
+        },
+      },
+      "Should reupload bookmarks with different keyword"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+
+    let entryByOldKeyword = await PlacesUtils.keywords.fetch("one");
+    ok(
+      !entryByOldKeyword,
+      "Should remove old entry when inserting bookmark with different keyword"
+    );
+    let entryByNewKeyword = await PlacesUtils.keywords.fetch("two");
+    equal(
+      entryByNewKeyword.url.href,
+      "http://example.com/a",
+      "Should return new keyword entry by URL"
+    );
+    let entryByURL = await PlacesUtils.keywords.fetch({
+      url: "http://example.com/a",
+    });
+    equal(entryByURL.keyword, "two", "Should return new entry by URL");
+  }
+
+  info("Update bookmark with different keyword");
+  {
+    await storeRecords(
+      buf,
+      shuffle([
+        {
+          id: "bookmarkAAAA",
+          parentid: "menu",
+          type: "bookmark",
+          title: "A",
+          bmkUri: "http://example.com/a",
+          keyword: "three",
+          dateAdded: dateAdded.getTime(),
+        },
+      ])
+    );
+    let changesToUpload = await buf.apply();
+    deepEqual(
+      await buf.fetchUnmergedGuids(),
+      ["bookmarkAAAA"],
+      "Should leave A with conflicting keyword unmerged"
+    );
+    deepEqual(
+      changesToUpload,
+      {
+        bookmarkAAAA: {
+          tombstone: false,
+          counter: 1,
+          synced: false,
+          cleartext: {
+            id: "bookmarkAAAA",
+            type: "bookmark",
+            parentid: "menu",
+            hasDupe: true,
+            parentName: BookmarksMenuTitle,
+            dateAdded: dateAdded.getTime(),
+            bmkUri: "http://example.com/a",
+            title: "A",
+            keyword: "three",
+          },
+        },
+        bookmarkAAA1: {
+          tombstone: false,
+          counter: 1,
+          synced: false,
+          cleartext: {
+            id: "bookmarkAAA1",
+            type: "bookmark",
+            parentid: "toolbar",
+            hasDupe: true,
+            parentName: BookmarksToolbarTitle,
+            dateAdded: dateAdded.getTime(),
+            bmkUri: "http://example.com/a",
+            title: "A1",
+            keyword: "three",
+          },
+        },
+      },
+      "Should reupload A and A1 with updated keyword"
+    );
+    await storeChangesInMirror(buf, changesToUpload);
+
+    let entryByOldKeyword = await PlacesUtils.keywords.fetch("two");
+    ok(
+      !entryByOldKeyword,
+      "Should remove old entry when updating bookmark keyword"
+    );
+    let entryByNewKeyword = await PlacesUtils.keywords.fetch("three");
+    equal(
+      entryByNewKeyword.url.href,
+      "http://example.com/a",
+      "Should return updated keyword entry by URL"
+    );
+    let entryByURL = await PlacesUtils.keywords.fetch({
+      url: "http://example.com/a",
+    });
+    equal(entryByURL.keyword, "three", "Should return updated entry by URL");
+  }
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_keywords() {
+  let buf = await openMirror("keywords");
+  let now = new Date();
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+        keyword: "one",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+        keyword: "two",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkCCCC",
+        title: "C",
+        url: "http://example.com/c",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkDDDD",
+        title: "D",
+        url: "http://example.com/d",
+        keyword: "three",
+        dateAdded: now,
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkAAAA",
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkDDDD",
+        ],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        keyword: "one",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        keyword: "two",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "menu",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        keyword: "three",
+        dateAdded: now.getTime(),
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Change keywords remotely");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        keyword: "two",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        dateAdded: now.getTime(),
+      },
+    ])
+  );
+
+  info("Change keywords locally");
+  await PlacesUtils.keywords.insert({
+    keyword: "four",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.keywords.remove("three");
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  deepEqual(
+    changesToUpload,
+    {
+      bookmarkCCCC: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkCCCC",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: now.getTime(),
+          bmkUri: "http://example.com/c",
+          title: "C",
+          keyword: "four",
+        },
+      },
+      bookmarkDDDD: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "bookmarkDDDD",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: now.getTime(),
+          bmkUri: "http://example.com/d",
+          title: "D",
+        },
+      },
+    },
+    "Should upload C with new keyword, D with keyword removed"
+  );
+
+  let entryForOne = await PlacesUtils.keywords.fetch("one");
+  ok(!entryForOne, "Should remove existing keyword from A");
+
+  let entriesForTwo = await fetchAllKeywords("two");
+  deepEqual(
+    entriesForTwo.map(entry => ({
+      keyword: entry.keyword,
+      url: entry.url.href,
+    })),
+    [
+      {
+        keyword: "two",
+        url: "http://example.com/a",
+      },
+    ],
+    "Should move keyword for B to A"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_keywords_complex() {
+  let buf = await openMirror("keywords_complex");
+  let now = new Date();
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+        keyword: "four",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkCCCC",
+        title: "C",
+        url: "http://example.com/c",
+        keyword: "five",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkDDDD",
+        title: "D",
+        url: "http://example.com/d",
+        dateAdded: now,
+      },
+      {
+        guid: "bookmarkEEEE",
+        title: "E",
+        url: "http://example.com/e",
+        keyword: "three",
+        dateAdded: now,
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkDDDD",
+          "bookmarkEEEE",
+        ],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        keyword: "four",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+        keyword: "five",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "menu",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkEEEE",
+        parentid: "menu",
+        type: "bookmark",
+        title: "E",
+        bmkUri: "http://example.com/e",
+        keyword: "three",
+        dateAdded: now.getTime(),
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkAAAA",
+          "bookmarkAAA1",
+          "bookmarkBBB1",
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkDDDD",
+          "bookmarkEEEE",
+        ],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        keyword: "one",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkAAA1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A (copy)",
+        bmkUri: "http://example.com/a",
+        keyword: "two",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkBBB1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        dateAdded: now.getTime(),
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C (remote)",
+        bmkUri: "http://example.com/c-remote",
+        keyword: "six",
+        dateAdded: now.getTime(),
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["bookmarkAAA1", "bookmarkAAAA", "bookmarkBBB1"],
+    "Should leave A1, A, B with conflicting keywords unmerged"
+  );
+
+  let expectedChangesToUpload = {
+    bookmarkBBBB: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkBBBB",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: now.getTime(),
+        bmkUri: "http://example.com/b",
+        title: "B",
+      },
+    },
+    bookmarkBBB1: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkBBB1",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: now.getTime(),
+        bmkUri: "http://example.com/b",
+        title: "B",
+      },
+    },
+    bookmarkAAAA: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkAAAA",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: now.getTime(),
+        bmkUri: "http://example.com/a",
+        title: "A",
+      },
+    },
+    bookmarkAAA1: {
+      tombstone: false,
+      counter: 1,
+      synced: false,
+      cleartext: {
+        id: "bookmarkAAA1",
+        type: "bookmark",
+        parentid: "menu",
+        hasDupe: true,
+        parentName: BookmarksMenuTitle,
+        dateAdded: now.getTime(),
+        bmkUri: "http://example.com/a",
+        title: "A (copy)",
+      },
+    },
+  };
+
+  // We'll take the keyword of either "bookmarkAAAA" or "bookmarkAAA1",
+  // depending on which we see first, and reupload the other.
+  let entriesForOne = await fetchAllKeywords("one");
+  let entriesForTwo = await fetchAllKeywords("two");
+  if (entriesForOne.length) {
+    ok(!entriesForTwo.length, "Should drop conflicting keyword from A1");
+    deepEqual(
+      entriesForOne.map(keyword => keyword.url.href),
+      ["http://example.com/a"],
+      "Should use A keyword for A and A1"
+    );
+    expectedChangesToUpload.bookmarkAAAA.cleartext.keyword = "one";
+    expectedChangesToUpload.bookmarkAAA1.cleartext.keyword = "one";
+  } else {
+    ok(!entriesForOne.length, "Should drop conflicting keyword from A");
+    deepEqual(
+      entriesForTwo.map(keyword => keyword.url.href),
+      ["http://example.com/a"],
+      "Should use A1 keyword for A and A1"
+    );
+    expectedChangesToUpload.bookmarkAAAA.cleartext.keyword = "two";
+    expectedChangesToUpload.bookmarkAAA1.cleartext.keyword = "two";
+  }
+  deepEqual(
+    changesToUpload,
+    expectedChangesToUpload,
+    "Should reupload all local records with corrected keywords"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "bookmarkAAAA",
+    "bookmarkAAA1",
+    "bookmarkBBB1",
+    "bookmarkBBBB",
+    "bookmarkCCCC",
+    "bookmarkDDDD",
+    "bookmarkEEEE",
+    PlacesUtils.bookmarks.menuGuid,
+  ]);
+  let expectedNotifications = [
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("bookmarkAAAA"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 0,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/a",
+        title: "A",
+        guid: "bookmarkAAAA",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("bookmarkAAA1"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 1,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/a",
+        title: "A (copy)",
+        guid: "bookmarkAAA1",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      name: "bookmark-added",
+      params: {
+        itemId: localItemIds.get("bookmarkBBB1"),
+        parentId: localItemIds.get(PlacesUtils.bookmarks.menuGuid),
+        index: 2,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/b",
+        title: "B",
+        guid: "bookmarkBBB1",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+      },
+    },
+    {
+      // These `bookmark-moved` notifications aren't necessary: we only moved
+      // (B C D E) to accomodate (A A1 B1), and Places doesn't usually fire move
+      // notifications for repositioned siblings. However, detecting and filtering
+      // these out complicates `noteObserverChanges`, so, for simplicity, we
+      // record and fire the extra notifications.
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        oldIndex: 0,
+        newIndex: 3,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkBBBB",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/b",
+        isTagging: false,
+        title: "B",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: now.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        oldIndex: 1,
+        newIndex: 4,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkCCCC",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/c-remote",
+        isTagging: false,
+        title: "C (remote)",
+        tags: "",
+        frecency: -1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: now.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkDDDD"),
+        oldIndex: 2,
+        newIndex: 5,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkDDDD",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/d",
+        isTagging: false,
+        title: "D",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: now.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-moved",
+      params: {
+        itemId: localItemIds.get("bookmarkEEEE"),
+        oldIndex: 3,
+        newIndex: 6,
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        guid: "bookmarkEEEE",
+        oldParentGuid: PlacesUtils.bookmarks.menuGuid,
+        newParentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        urlHref: "http://example.com/e",
+        isTagging: false,
+        title: "E",
+        tags: "",
+        frecency: 1,
+        hidden: false,
+        visitCount: 0,
+        dateAdded: now.getTime(),
+        lastVisitDate: null,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        title: "C (remote)",
+        guid: "bookmarkCCCC",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+    {
+      name: "bookmark-url-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        urlHref: "http://example.com/c-remote",
+        guid: "bookmarkCCCC",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+        source: PlacesUtils.bookmarks.SOURCES.SYNC,
+        isTagging: false,
+      },
+    },
+  ];
+  observer.check(expectedNotifications);
+
+  let entriesForFour = await fetchAllKeywords("four");
+  ok(!entriesForFour.length, "Should remove all keywords for B");
+
+  let entriesForOldC = await fetchAllKeywords({
+    url: "http://example.com/c",
+  });
+  ok(!entriesForOldC.length, "Should remove all keywords from old C URL");
+  let entriesForNewC = await fetchAllKeywords({
+    url: "http://example.com/c-remote",
+  });
+  deepEqual(
+    entriesForNewC.map(entry => entry.keyword),
+    ["six"],
+    "Should add new keyword to new C URL"
+  );
+
+  let entriesForD = await fetchAllKeywords("http://example.com/d");
+  ok(!entriesForD.length, "Should not add keywords to D");
+
+  let entriesForThree = await fetchAllKeywords("three");
+  deepEqual(
+    entriesForThree.map(keyword => keyword.url.href),
+    ["http://example.com/e"],
+    "Should not change keywords for E"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_tags_complex() {
+  let buf = await openMirror("tags_complex");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAA1",
+        title: "A1",
+        url: "http://example.com/a",
+        tags: ["one", "two"],
+      },
+      {
+        guid: "bookmarkAAA2",
+        title: "A2",
+        url: "http://example.com/a",
+        tags: ["one", "two"],
+      },
+      {
+        guid: "bookmarkBBB1",
+        title: "B1",
+        url: "http://example.com/b",
+        tags: ["one"],
+      },
+      {
+        guid: "bookmarkBBB2",
+        title: "B2",
+        url: "http://example.com/b",
+        tags: ["one"],
+      },
+      {
+        guid: "bookmarkCCC1",
+        title: "C1",
+        url: "http://example.com/c",
+        tags: ["two", "three"],
+      },
+      {
+        guid: "bookmarkCCC2",
+        title: "C2",
+        url: "http://example.com/c",
+        tags: ["two", "three"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkAAA1",
+          "bookmarkAAA2",
+          "bookmarkBBB1",
+          "bookmarkBBB2",
+          "bookmarkCCC1",
+          "bookmarkCCC2",
+        ],
+      },
+      {
+        id: "bookmarkAAA1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two"],
+      },
+      {
+        id: "bookmarkAAA2",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two"],
+      },
+      {
+        id: "bookmarkBBB1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B1",
+        bmkUri: "http://example.com/b",
+        tags: ["one"],
+      },
+      {
+        id: "bookmarkBBB2",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B2",
+        bmkUri: "http://example.com/b",
+        tags: ["one"],
+      },
+      {
+        id: "bookmarkCCC1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C1",
+        bmkUri: "http://example.com/c",
+        tags: ["two", "three"],
+      },
+      {
+        id: "bookmarkCCC2",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C2",
+        bmkUri: "http://example.com/c",
+        tags: ["two", "three"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Add tags for B locally");
+  PlacesUtils.tagging.tagURI(Services.io.newURI("http://example.com/b"), [
+    "four",
+    "five",
+  ]);
+
+  info("Remove tag from C locally");
+  PlacesUtils.tagging.untagURI(Services.io.newURI("http://example.com/c"), [
+    "two",
+  ]);
+
+  info("Update tags for A remotely");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkAAA1",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A1",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two", "four", "six"],
+      },
+      {
+        id: "bookmarkAAA2",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A2",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two", "four", "six"],
+      },
+    ])
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+
+  let datesAdded = await promiseManyDatesAdded([
+    "bookmarkBBB1",
+    "bookmarkBBB2",
+    "bookmarkCCC1",
+    "bookmarkCCC2",
+  ]);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+  deepEqual(
+    changesToUpload,
+    {
+      bookmarkBBB1: {
+        counter: 2,
+        synced: false,
+        tombstone: false,
+        cleartext: {
+          id: "bookmarkBBB1",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: datesAdded.get("bookmarkBBB1"),
+          bmkUri: "http://example.com/b",
+          title: "B1",
+          tags: ["five", "four", "one"],
+        },
+      },
+      bookmarkBBB2: {
+        counter: 2,
+        synced: false,
+        tombstone: false,
+        cleartext: {
+          id: "bookmarkBBB2",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: datesAdded.get("bookmarkBBB2"),
+          bmkUri: "http://example.com/b",
+          title: "B2",
+          tags: ["five", "four", "one"],
+        },
+      },
+      bookmarkCCC1: {
+        counter: 1,
+        synced: false,
+        tombstone: false,
+        cleartext: {
+          id: "bookmarkCCC1",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: datesAdded.get("bookmarkCCC1"),
+          bmkUri: "http://example.com/c",
+          title: "C1",
+          tags: ["three"],
+        },
+      },
+      bookmarkCCC2: {
+        counter: 1,
+        synced: false,
+        tombstone: false,
+        cleartext: {
+          id: "bookmarkCCC2",
+          type: "bookmark",
+          parentid: "menu",
+          hasDupe: true,
+          parentName: BookmarksMenuTitle,
+          dateAdded: datesAdded.get("bookmarkCCC2"),
+          bmkUri: "http://example.com/c",
+          title: "C2",
+          tags: ["three"],
+        },
+      },
+    },
+    "Should upload local records with new tags"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      guid: PlacesUtils.bookmarks.menuGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: BookmarksMenuTitle,
+      children: [
+        {
+          guid: "bookmarkAAA1",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 0,
+          title: "A1",
+          url: "http://example.com/a",
+          tags: ["four", "one", "six", "two"],
+        },
+        {
+          guid: "bookmarkAAA2",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 1,
+          title: "A2",
+          url: "http://example.com/a",
+          tags: ["four", "one", "six", "two"],
+        },
+        {
+          guid: "bookmarkBBB1",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 2,
+          title: "B1",
+          url: "http://example.com/b",
+          tags: ["five", "four", "one"],
+        },
+        {
+          guid: "bookmarkBBB2",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 3,
+          title: "B2",
+          url: "http://example.com/b",
+          tags: ["five", "four", "one"],
+        },
+        {
+          guid: "bookmarkCCC1",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 4,
+          title: "C1",
+          url: "http://example.com/c",
+          tags: ["three"],
+        },
+        {
+          guid: "bookmarkCCC2",
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          index: 5,
+          title: "C2",
+          url: "http://example.com/c",
+          tags: ["three"],
+        },
+      ],
+    },
+    "Should update local items with new tags"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_tags() {
+  let buf = await openMirror("tags");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+        tags: ["one", "two", "three", "four"],
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+        tags: ["five", "six"],
+      },
+      {
+        guid: "bookmarkCCCC",
+        title: "C",
+        url: "http://example.com/c",
+      },
+      {
+        guid: "bookmarkDDDD",
+        title: "D",
+        url: "http://example.com/d",
+        tags: ["seven", "eight", "nine"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: [
+          "bookmarkAAAA",
+          "bookmarkBBBB",
+          "bookmarkCCCC",
+          "bookmarkDDDD",
+        ],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two", "three", "four"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        tags: ["five", "six"],
+      },
+      {
+        id: "bookmarkCCCC",
+        parentid: "menu",
+        type: "bookmark",
+        title: "C",
+        bmkUri: "http://example.com/c",
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "menu",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        tags: ["seven", "eight", "nine"],
+      },
+    ]),
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Change tags remotely");
+  await storeRecords(
+    buf,
+    shuffle([
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+        tags: ["one", "two", "ten"],
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        bmkUri: "http://example.com/b",
+        tags: [],
+      },
+    ])
+  );
+
+  info("Change tags locally");
+  PlacesUtils.tagging.tagURI(Services.io.newURI("http://example.com/c"), [
+    "eleven",
+    "twelve",
+  ]);
+
+  let wait = PlacesTestUtils.waitForNotification("bookmark-removed", events =>
+    events.some(event => event.parentGuid == PlacesUtils.bookmarks.tagsGuid)
+  );
+
+  PlacesUtils.tagging.untagURI(
+    Services.io.newURI("http://example.com/d"),
+    null
+  );
+
+  await wait;
+
+  await new Promise(resolve => Services.tm.dispatchToMainThread(resolve));
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkCCCC", "bookmarkDDDD"],
+      deleted: [],
+    },
+    "Should upload local records with new tags"
+  );
+
+  deepEqual(
+    changesToUpload.bookmarkCCCC.cleartext.tags.sort(),
+    ["eleven", "twelve"],
+    "Should upload record with new tags for C"
+  );
+  ok(
+    !changesToUpload.bookmarkDDDD.cleartext.tags,
+    "Should upload record for D with tags removed"
+  );
+
+  let tagsForA = PlacesUtils.tagging.getTagsForURI(
+    Services.io.newURI("http://example.com/a")
+  );
+  deepEqual(tagsForA, ["one", "ten", "two"], "Should change tags for A");
+
+  let tagsForB = PlacesUtils.tagging.getTagsForURI(
+    Services.io.newURI("http://example.com/b")
+  );
+  deepEqual(tagsForB, [], "Should remove all tags from B");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_rewrite_tag_queries() {
+  let buf = await openMirror("rewrite_tag_queries");
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkDDDD",
+        title: "D",
+        url: "http://example.com/d",
+        tags: ["kitty"],
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkDDDD"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkDDDD",
+        parentid: "menu",
+        type: "bookmark",
+        title: "D",
+        bmkUri: "http://example.com/d",
+        tags: ["kitty"],
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Add tag queries for new and existing tags");
+  await storeRecords(buf, [
+    {
+      id: "toolbar",
+      parentid: "places",
+      type: "folder",
+      children: ["queryBBBBBBB", "queryCCCCCCC", "bookmarkEEEE"],
+    },
+    {
+      id: "queryBBBBBBB",
+      parentid: "toolbar",
+      type: "query",
+      title: "Tagged stuff",
+      bmkUri: "place:type=7&folder=999",
+      folderName: "taggy",
+    },
+    {
+      id: "queryCCCCCCC",
+      parentid: "toolbar",
+      type: "query",
+      title: "Cats",
+      bmkUri: "place:type=7&folder=888",
+      folderName: "kitty",
+    },
+    {
+      id: "bookmarkEEEE",
+      parentid: "toolbar",
+      type: "bookmark",
+      title: "E",
+      bmkUri: "http://example.com/e",
+      tags: ["taggy"],
+    },
+  ]);
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    ["queryBBBBBBB", "queryCCCCCCC"],
+    "Should leave rewritten queries unmerged"
+  );
+
+  deepEqual(
+    changesToUpload,
+    {
+      queryBBBBBBB: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "queryBBBBBBB",
+          type: "query",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: undefined,
+          bmkUri: "place:tag=taggy",
+          title: "Tagged stuff",
+          folderName: "taggy",
+        },
+      },
+      queryCCCCCCC: {
+        tombstone: false,
+        counter: 1,
+        synced: false,
+        cleartext: {
+          id: "queryCCCCCCC",
+          type: "query",
+          parentid: "toolbar",
+          hasDupe: true,
+          parentName: BookmarksToolbarTitle,
+          dateAdded: undefined,
+          bmkUri: "place:tag=kitty",
+          title: "Cats",
+          folderName: "kitty",
+        },
+      },
+    },
+    "Should reupload (E C) with rewritten URLs"
+  );
+
+  let bmWithTaggy = await PlacesUtils.bookmarks.fetch({ tags: ["taggy"] });
+  equal(
+    bmWithTaggy.url.href,
+    "http://example.com/e",
+    "Should insert bookmark with new tag"
+  );
+
+  let bmWithKitty = await PlacesUtils.bookmarks.fetch({ tags: ["kitty"] });
+  equal(
+    bmWithKitty.url.href,
+    "http://example.com/d",
+    "Should retain existing tag"
+  );
+
+  let { root: toolbarContainer } = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid,
+    false,
+    true
+  );
+  equal(
+    toolbarContainer.childCount,
+    3,
+    "Should add queries and bookmark to toolbar"
+  );
+
+  let containerForB = PlacesUtils.asContainer(toolbarContainer.getChild(0));
+  containerForB.containerOpen = true;
+  for (let i = 0; i < containerForB.childCount; ++i) {
+    let child = containerForB.getChild(i);
+    equal(
+      child.uri,
+      "http://example.com/e",
+      `Rewritten tag query B should have tagged child node at ${i}`
+    );
+  }
+  containerForB.containerOpen = false;
+
+  let containerForC = PlacesUtils.asContainer(toolbarContainer.getChild(1));
+  containerForC.containerOpen = true;
+  for (let i = 0; i < containerForC.childCount; ++i) {
+    let child = containerForC.getChild(i);
+    equal(
+      child.uri,
+      "http://example.com/d",
+      `Rewritten tag query C should have tagged child node at ${i}`
+    );
+  }
+  containerForC.containerOpen = false;
+
+  toolbarContainer.containerOpen = false;
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_date_added() {
+  let buf = await openMirror("date_added");
+
+  let aDateAdded = new Date(Date.now() - 1 * 24 * 60 * 60 * 1000);
+  let bDateAdded = new Date();
+
+  info("Set up mirror");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        dateAdded: aDateAdded,
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        dateAdded: bDateAdded,
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await storeRecords(
+    buf,
+    [
+      {
+        id: "menu",
+        parentid: "places",
+        type: "folder",
+        children: ["bookmarkAAAA", "bookmarkBBBB"],
+      },
+      {
+        id: "bookmarkAAAA",
+        parentid: "menu",
+        type: "bookmark",
+        title: "A",
+        dateAdded: aDateAdded.getTime(),
+        bmkUri: "http://example.com/a",
+      },
+      {
+        id: "bookmarkBBBB",
+        parentid: "menu",
+        type: "bookmark",
+        title: "B",
+        dateAdded: bDateAdded.getTime(),
+        bmkUri: "http://example.com/b",
+      },
+    ],
+    { needsMerge: false }
+  );
+  await PlacesTestUtils.markBookmarksAsSynced();
+
+  info("Make remote changes");
+  let bNewDateAdded = new Date(bDateAdded.getTime() - 1 * 60 * 60 * 1000);
+  await storeRecords(buf, [
+    {
+      id: "bookmarkAAAA",
+      parentid: "menu",
+      type: "bookmark",
+      title: "A (remote)",
+      dateAdded: Date.now(),
+      bmkUri: "http://example.com/a",
+    },
+    {
+      id: "bookmarkBBBB",
+      parentid: "menu",
+      type: "bookmark",
+      title: "B (remote)",
+      dateAdded: bNewDateAdded.getTime(),
+      bmkUri: "http://example.com/b",
+    },
+  ]);
+
+  info("Apply remote");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  let idsToUpload = inspectChangeRecords(changesToUpload);
+  deepEqual(
+    idsToUpload,
+    {
+      updated: ["bookmarkAAAA"],
+      deleted: [],
+    },
+    "Should flag A for weak reupload"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+  ]);
+  observer.check([
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkAAAA"),
+        title: "A (remote)",
+        guid: "bookmarkAAAA",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        title: "B (remote)",
+        guid: "bookmarkBBBB",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+  ]);
+
+  let changeCounter = changesToUpload.bookmarkAAAA.counter;
+  strictEqual(changeCounter, 0, "Should not bump change counter for A");
+
+  let aInfo = await PlacesUtils.bookmarks.fetch("bookmarkAAAA");
+  equal(aInfo.title, "A (remote)", "Should change local title for A");
+  deepEqual(
+    aInfo.dateAdded,
+    aDateAdded,
+    "Should not change date added for A to newer remote date"
+  );
+
+  let bInfo = await PlacesUtils.bookmarks.fetch("bookmarkBBBB");
+  equal(bInfo.title, "B (remote)", "Should change local title for B");
+  deepEqual(
+    bInfo.dateAdded,
+    bNewDateAdded,
+    "Should take older date added for B"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+// Bug 1472435.
+add_task(async function test_duplicate_url_rows() {
+  let buf = await openMirror("test_duplicate_url_rows");
+
+  let placesToInsert = [
+    {
+      guid: "placeAAAAAAA",
+      href: "http://example.com",
+    },
+    {
+      guid: "placeBBBBBBB",
+      href: "http://example.com",
+    },
+    {
+      guid: "placeCCCCCCC",
+      href: "http://example.com/c",
+    },
+  ];
+
+  let itemsToInsert = [
+    {
+      guid: "bookmarkAAAA",
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      placeGuid: "placeAAAAAAA",
+      localTitle: "A",
+      remoteTitle: "A (remote)",
+    },
+    {
+      guid: "bookmarkBBBB",
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      placeGuid: "placeBBBBBBB",
+      localTitle: "B",
+      remoteTitle: "B (remote)",
+    },
+    {
+      guid: "bookmarkCCCC",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      placeGuid: "placeCCCCCCC",
+      localTitle: "C",
+      remoteTitle: "C (remote)",
+    },
+  ];
+
+  info("Manually insert local and remote items with duplicate URLs");
+  await buf.db.executeTransaction(async function () {
+    for (let { guid, href } of placesToInsert) {
+      let url = new URL(href);
+      await buf.db.executeCached(
+        `
+        INSERT INTO moz_places(url, url_hash, rev_host, hidden, frecency, guid)
+        VALUES(:url, hash(:url), :revHost, 0, -1, :guid)`,
+        { url: url.href, revHost: PlacesUtils.getReversedHost(url), guid }
+      );
+
+      await buf.db.executeCached(
+        `
+        INSERT INTO urls(guid, url, hash, revHost)
+        VALUES(:guid, :url, hash(:url), :revHost)`,
+        { guid, url: url.href, revHost: PlacesUtils.getReversedHost(url) }
+      );
+    }
+
+    for (let {
+      guid,
+      parentGuid,
+      placeGuid,
+      localTitle,
+      remoteTitle,
+    } of itemsToInsert) {
+      await buf.db.executeCached(
+        `
+        INSERT INTO moz_bookmarks(guid, parent, fk, position, type, title,
+                                  syncStatus, syncChangeCounter)
+        VALUES(:guid, (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+               (SELECT id FROM moz_places WHERE guid = :placeGuid),
+               (SELECT count(*) FROM moz_bookmarks b
+                JOIN moz_bookmarks p ON p.id = b.parent
+                WHERE p.guid = :parentGuid), :type, :localTitle,
+                :syncStatus, 1)`,
+        {
+          guid,
+          parentGuid,
+          placeGuid,
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          localTitle,
+          syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        }
+      );
+
+      await buf.db.executeCached(
+        `
+        INSERT INTO items(guid, parentGuid, needsMerge, kind, title, urlId)
+        VALUES(:guid, :parentGuid, 1, :kind, :remoteTitle,
+               (SELECT id FROM urls WHERE guid = :placeGuid))`,
+        {
+          guid,
+          parentGuid,
+          placeGuid,
+          kind: Ci.mozISyncedBookmarksMerger.KIND_BOOKMARK,
+          remoteTitle,
+        }
+      );
+
+      await buf.db.executeCached(
+        `
+        INSERT INTO structure(guid, parentGuid, position)
+        VALUES(:guid, :parentGuid,
+               IFNULL((SELECT count(*) FROM structure
+                       WHERE parentGuid = :parentGuid), 0))`,
+        { guid, parentGuid }
+      );
+    }
+  });
+
+  info("Apply mirror");
+  let observer = expectBookmarkChangeNotifications();
+  let changesToUpload = await buf.apply({
+    notifyInStableOrder: true,
+  });
+  deepEqual(
+    await buf.fetchUnmergedGuids(),
+    [
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.mobileGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+    ],
+    "Should leave roots unmerged"
+  );
+  deepEqual(
+    Object.keys(changesToUpload).sort(),
+    ["menu", "mobile", "toolbar", "unfiled"],
+    "Should upload roots"
+  );
+
+  await assertLocalTree(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+      index: 0,
+      title: "",
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 0,
+          title: BookmarksMenuTitle,
+          children: [
+            {
+              guid: "bookmarkAAAA",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "A (remote)",
+              url: "http://example.com/",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 1,
+          title: BookmarksToolbarTitle,
+          children: [
+            {
+              guid: "bookmarkBBBB",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "B (remote)",
+              url: "http://example.com/",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 3,
+          title: UnfiledBookmarksTitle,
+          children: [
+            {
+              guid: "bookmarkCCCC",
+              type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+              index: 0,
+              title: "C (remote)",
+              url: "http://example.com/c",
+            },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          index: 4,
+          title: MobileBookmarksTitle,
+        },
+      ],
+    },
+    "Should update titles for items with duplicate URLs"
+  );
+
+  let localItemIds = await PlacesTestUtils.promiseManyItemIds([
+    "bookmarkAAAA",
+    "bookmarkBBBB",
+    "bookmarkCCCC",
+  ]);
+  observer.check([
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkAAAA"),
+        title: "A (remote)",
+        guid: "bookmarkAAAA",
+        parentGuid: PlacesUtils.bookmarks.menuGuid,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkBBBB"),
+        title: "B (remote)",
+        guid: "bookmarkBBBB",
+        parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      },
+    },
+    {
+      name: "bookmark-title-changed",
+      params: {
+        itemId: localItemIds.get("bookmarkCCCC"),
+        title: "C (remote)",
+        guid: "bookmarkCCCC",
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      },
+    },
+  ]);
+
+  info("Remove duplicate URLs from Places to avoid tripping debug asserts");
+  await buf.db.executeTransaction(async function () {
+    for (let { guid } of placesToInsert) {
+      await buf.db.executeCached(
+        `
+        DELETE FROM moz_places WHERE guid = :guid`,
+        { guid }
+      );
+    }
+  });
+
+  await storeChangesInMirror(buf, changesToUpload);
+  deepEqual(await buf.fetchUnmergedGuids(), [], "Should merge all items");
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_duplicate_local_tags() {
+  let buf = await openMirror("duplicate_local_tags");
+  let now = new Date();
+
+  info("Insert A");
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkAAAA",
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "A",
+    url: "http://example.com/a",
+    dateAdded: now,
+  });
+
+  // Each tag folder should have unique tag entries, but the tagging service
+  // doesn't enforce this. We should still sync the correct set of tags,
+  // though, even if there are duplicates for the same URL.
+  info("Manually insert local tags for A");
+  for (let [tag, dupes] of [
+    ["one", 2],
+    ["two", 1],
+    ["three", 2],
+  ]) {
+    let tagFolderInfo = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.tagsGuid,
+      title: tag,
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+    for (let i = 0; i < dupes; ++i) {
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: tagFolderInfo.guid,
+        url: "http://example.com/a",
+      });
+    }
+  }
+
+  let tagsForA = PlacesUtils.tagging.getTagsForURI(
+    Services.io.newURI("http://example.com/a")
+  );
+  deepEqual(
+    tagsForA,
+    ["one", "one", "three", "three", "two"],
+    "Tagging service should return duplicate tags"
+  );
+
+  info("Apply remote");
+  let changesToUpload = await buf.apply();
+  deepEqual(
+    changesToUpload.bookmarkAAAA.cleartext,
+    {
+      id: "bookmarkAAAA",
+      type: "bookmark",
+      parentid: "menu",
+      hasDupe: true,
+      parentName: BookmarksMenuTitle,
+      dateAdded: now.getTime(),
+      bmkUri: "http://example.com/a",
+      title: "A",
+      tags: ["one", "three", "two"],
+    },
+    "Should upload A with tags"
+  );
+
+  await buf.finalize();
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
diff --git a/toolkit/components/places/tests/sync/test_sync_utils.js b/toolkit/components/places/tests/sync/test_sync_utils.js
new file mode 100644
index 0000000000..8396ac2f0d
--- /dev/null
+++ b/toolkit/components/places/tests/sync/test_sync_utils.js
@@ -0,0 +1,3130 @@
+ChromeUtils.defineESModuleGetters(this, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+var makeGuid = PlacesUtils.history.makeGuid;
+
+function shuffle(array) {
+  let results = [];
+  for (let i = 0; i < array.length; ++i) {
+    let randomIndex = Math.floor(Math.random() * (i + 1));
+    results[i] = results[randomIndex];
+    results[randomIndex] = array[i];
+  }
+  return results;
+}
+
+async function assertTagForURLs(tag, urls, message) {
+  let taggedURLs = new Set();
+  await PlacesUtils.bookmarks.fetch({ tags: [tag] }, b =>
+    taggedURLs.add(b.url.href)
+  );
+  deepEqual(
+    Array.from(taggedURLs).sort(compareAscending),
+    urls.sort(compareAscending),
+    message
+  );
+}
+
+function assertURLHasTags(url, tags, message) {
+  let actualTags = PlacesUtils.tagging.getTagsForURI(uri(url));
+  deepEqual(actualTags.sort(compareAscending), tags, message);
+}
+
+var populateTree = async function populate(parentGuid, ...items) {
+  let guids = {};
+
+  for (let index = 0; index < items.length; index++) {
+    let item = items[index];
+    let guid = makeGuid();
+
+    switch (item.kind) {
+      case "bookmark":
+      case "query":
+        await PlacesUtils.bookmarks.insert({
+          type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+          url: item.url,
+          title: item.title,
+          parentGuid,
+          guid,
+          index,
+        });
+        break;
+
+      case "separator":
+        await PlacesUtils.bookmarks.insert({
+          type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          parentGuid,
+          guid,
+        });
+        break;
+
+      case "folder":
+        await PlacesUtils.bookmarks.insert({
+          type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          title: item.title,
+          parentGuid,
+          guid,
+        });
+        if (item.children) {
+          Object.assign(guids, await populate(guid, ...item.children));
+        }
+        break;
+
+      default:
+        throw new Error(`Unsupported item type: ${item.type}`);
+    }
+
+    guids[item.title] = guid;
+  }
+
+  return guids;
+};
+
+var moveSyncedBookmarksToUnsyncedParent = async function () {
+  info("Insert synced bookmarks");
+  let syncedGuids = await populateTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      kind: "folder",
+      title: "folder",
+      children: [
+        {
+          kind: "bookmark",
+          title: "childBmk",
+          url: "https://example.org",
+        },
+      ],
+    },
+    {
+      kind: "bookmark",
+      title: "topBmk",
+      url: "https://example.com",
+    }
+  );
+  // Pretend we've synced each bookmark at least once.
+  await PlacesTestUtils.setBookmarkSyncFields(
+    ...Object.values(syncedGuids).map(guid => ({
+      guid,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    }))
+  );
+
+  info("Make new folder");
+  let unsyncedFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "unsyncedFolder",
+  });
+
+  info("Move synced bookmarks into unsynced new folder");
+  for (let guid of Object.values(syncedGuids)) {
+    await PlacesUtils.bookmarks.update({
+      guid,
+      parentGuid: unsyncedFolder.guid,
+      index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+    });
+  }
+
+  return { syncedGuids, unsyncedFolder };
+};
+
+var setChangesSynced = async function (changes) {
+  for (let recordId in changes) {
+    changes[recordId].synced = true;
+  }
+  await PlacesSyncUtils.bookmarks.pushChanges(changes);
+};
+
+var ignoreChangedRoots = async function () {
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  let expectedRoots = ["menu", "mobile", "toolbar", "unfiled"];
+  if (!ObjectUtils.deepEqual(Object.keys(changes).sort(), expectedRoots)) {
+    // Make sure the previous test cleaned up.
+    throw new Error(
+      `Unexpected changes at start of test: ${JSON.stringify(changes)}`
+    );
+  }
+  await setChangesSynced(changes);
+};
+
+add_task(async function test_fetchURLFrecency() {
+  // Add visits to the following URLs and then check if frecency for those URLs is not -1.
+  let arrayOfURLsToVisit = [
+    "https://www.mozilla.org/en-US/",
+    "http://getfirefox.com",
+    "http://getthunderbird.com",
+  ];
+  for (let url of arrayOfURLsToVisit) {
+    await PlacesTestUtils.addVisits(url);
+  }
+  for (let url of arrayOfURLsToVisit) {
+    let frecency = await PlacesSyncUtils.history.fetchURLFrecency(url);
+    equal(typeof frecency, "number", "The frecency should be of type: number");
+    notEqual(
+      frecency,
+      -1,
+      "The frecency of this url should be different than -1"
+    );
+  }
+  // Do not add visits to the following URLs, and then check if frecency for those URLs is -1.
+  let arrayOfURLsNotVisited = ["https://bugzilla.org", "https://example.org"];
+  for (let url of arrayOfURLsNotVisited) {
+    let frecency = await PlacesSyncUtils.history.fetchURLFrecency(url);
+    equal(frecency, -1, "The frecency of this url should be -1");
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_determineNonSyncableGuids() {
+  // Add visits to the following URLs with different transition types.
+  let arrayOfVisits = [
+    { uri: "https://www.mozilla.org/en-US/", transition: TRANSITION_TYPED },
+    { uri: "http://getfirefox.com/", transition: TRANSITION_LINK },
+    { uri: "http://getthunderbird.com/", transition: TRANSITION_FRAMED_LINK },
+    { uri: "http://downloads.com/", transition: TRANSITION_DOWNLOAD },
+  ];
+  for (let visit of arrayOfVisits) {
+    await PlacesTestUtils.addVisits(visit);
+  }
+
+  // Fetch the guid for each visit.
+  let guids = [];
+  let dictURLGuid = {};
+  for (let visit of arrayOfVisits) {
+    let guid = await PlacesSyncUtils.history.fetchGuidForURL(visit.uri);
+    guids.push(guid);
+    dictURLGuid[visit.uri] = guid;
+  }
+
+  // Filter the visits.
+  let filteredGuids = await PlacesSyncUtils.history.determineNonSyncableGuids(
+    guids
+  );
+
+  let filtered = [TRANSITION_FRAMED_LINK, TRANSITION_DOWNLOAD];
+  // Check if the filtered visits are of type TRANSITION_FRAMED_LINK.
+  for (let visit of arrayOfVisits) {
+    if (filtered.includes(visit.transition)) {
+      ok(
+        filteredGuids.includes(dictURLGuid[visit.uri]),
+        "This url should be one of the filtered guids."
+      );
+    } else {
+      ok(
+        !filteredGuids.includes(dictURLGuid[visit.uri]),
+        "This url should not be one of the filtered guids."
+      );
+    }
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_changeGuid() {
+  // Add some visits of the following URLs.
+  let arrayOfURLsToVisit = [
+    "https://www.mozilla.org/en-US/",
+    "http://getfirefox.com/",
+    "http://getthunderbird.com/",
+  ];
+  for (let url of arrayOfURLsToVisit) {
+    await PlacesTestUtils.addVisits(url);
+  }
+
+  for (let url of arrayOfURLsToVisit) {
+    let originalGuid = await PlacesSyncUtils.history.fetchGuidForURL(url);
+    let newGuid = makeGuid();
+
+    // Change the original GUID for the new GUID.
+    await PlacesSyncUtils.history.changeGuid(url, newGuid);
+
+    // Fetch the GUID for this URL.
+    let newGuidFetched = await PlacesSyncUtils.history.fetchGuidForURL(url);
+
+    // Check that the URL has the new GUID as its GUID and not the original one.
+    equal(
+      newGuid,
+      newGuidFetched,
+      "These should be equal since we changed the guid for the visit."
+    );
+    notEqual(
+      originalGuid,
+      newGuidFetched,
+      "These should be different since we changed the guid for the visit."
+    );
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_fetchVisitsForURL() {
+  // Get the date for this moment and a date for a minute ago.
+  let now = new Date();
+  let aMinuteAgo = new Date(now.getTime() - 1 * 60000);
+
+  // Add some visits of the following URLs, specifying the transition and the visit date.
+  let arrayOfVisits = [
+    {
+      uri: "https://www.mozilla.org/en-US/",
+      transition: TRANSITION_TYPED,
+      visitDate: aMinuteAgo,
+    },
+    {
+      uri: "http://getfirefox.com/",
+      transition: TRANSITION_LINK,
+      visitDate: aMinuteAgo,
+    },
+    {
+      uri: "http://getthunderbird.com/",
+      transition: TRANSITION_LINK,
+      visitDate: aMinuteAgo,
+    },
+  ];
+  for (let elem of arrayOfVisits) {
+    await PlacesTestUtils.addVisits(elem);
+  }
+
+  for (let elem of arrayOfVisits) {
+    // Fetch all the visits for this URL.
+    let visits = await PlacesSyncUtils.history.fetchVisitsForURL(elem.uri);
+    // Since the visit we added will be the last one in the collection of visits, we get the index of it.
+    let iLast = visits.length - 1;
+
+    // The date is saved in _micro_seconds, here we change it to milliseconds.
+    let dateInMilliseconds = visits[iLast].date * 0.001;
+
+    // Check that the info we provided for this URL is the same one retrieved.
+    equal(
+      dateInMilliseconds,
+      elem.visitDate.getTime(),
+      "The date we provided should be the same we retrieved."
+    );
+    equal(
+      visits[iLast].type,
+      elem.transition,
+      "The transition type we provided should be the same we retrieved."
+    );
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_fetchGuidForURL() {
+  // Add some visits of the following URLs.
+  let arrayOfURLsToVisit = [
+    "https://www.mozilla.org/en-US/",
+    "http://getfirefox.com/",
+    "http://getthunderbird.com/",
+  ];
+  for (let url of arrayOfURLsToVisit) {
+    await PlacesTestUtils.addVisits(url);
+  }
+
+  // This tries to test fetchGuidForURL in two ways:
+  // 1- By fetching the GUID, and then using that GUID to retrieve the info of the visit.
+  //    It then compares the URL with the URL that is on the visits info.
+  // 2- By creating a new GUID, changing the GUID for the visit, fetching the GUID and comparing them.
+  for (let url of arrayOfURLsToVisit) {
+    let guid = await PlacesSyncUtils.history.fetchGuidForURL(url);
+    let info = await PlacesSyncUtils.history.fetchURLInfoForGuid(guid);
+
+    let newGuid = makeGuid();
+    await PlacesSyncUtils.history.changeGuid(url, newGuid);
+    let newGuid2 = await PlacesSyncUtils.history.fetchGuidForURL(url);
+
+    equal(
+      url,
+      info.url,
+      "The url provided and the url retrieved should be the same."
+    );
+    equal(
+      newGuid,
+      newGuid2,
+      "The changed guid and the retrieved guid should be the same."
+    );
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_fetchURLInfoForGuid() {
+  // Add some visits of the following URLs. specifying the title.
+  let visits = [
+    { uri: "https://www.mozilla.org/en-US/", title: "mozilla" },
+    { uri: "http://getfirefox.com/", title: "firefox" },
+    { uri: "http://getthunderbird.com/", title: "thunderbird" },
+    { uri: "http://quantum.mozilla.com/", title: null },
+  ];
+  for (let visit of visits) {
+    await PlacesTestUtils.addVisits(visit);
+  }
+
+  for (let visit of visits) {
+    let guid = await PlacesSyncUtils.history.fetchGuidForURL(visit.uri);
+    let info = await PlacesSyncUtils.history.fetchURLInfoForGuid(guid);
+
+    // Compare the info returned by fetchURLInfoForGuid,
+    // URL and title should match while frecency must be different than -1.
+    equal(
+      info.url,
+      visit.uri,
+      "The url provided should be the same as the url retrieved."
+    );
+    equal(
+      info.title,
+      visit.title || "",
+      "The title provided should be the same as the title retrieved."
+    );
+    notEqual(
+      info.frecency,
+      -1,
+      "The frecency of the visit should be different than -1."
+    );
+  }
+
+  // Create a "fake" GUID and check that the result of fetchURLInfoForGuid is null.
+  let guid = makeGuid();
+  let info = await PlacesSyncUtils.history.fetchURLInfoForGuid(guid);
+
+  equal(
+    info,
+    null,
+    "The information object of a non-existent guid should be null."
+  );
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_getAllURLs() {
+  // Add some visits of the following URLs.
+  let arrayOfURLsToVisit = [
+    "https://www.mozilla.org/en-US/",
+    "http://getfirefox.com/",
+    "http://getthunderbird.com/",
+  ];
+  for (let url of arrayOfURLsToVisit) {
+    await PlacesTestUtils.addVisits(url);
+  }
+
+  // Get all URLs.
+  let allURLs = await PlacesSyncUtils.history.getAllURLs({
+    since: new Date(Date.now() - 2592000000),
+    limit: 5000,
+  });
+
+  // The amount of URLs must be the same in both collections.
+  equal(
+    allURLs.length,
+    arrayOfURLsToVisit.length,
+    "The amount of urls retrived should match the amount of urls provided."
+  );
+
+  // Check that the correct URLs were retrived.
+  for (let url of arrayOfURLsToVisit) {
+    ok(
+      allURLs.includes(url),
+      "The urls retrieved should match the ones used in this test."
+    );
+  }
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_getAllURLs_skips_downloads() {
+  // Add some visits of the following URLs.
+  let arrayOfURLsToVisit = [
+    "https://www.mozilla.org/en-US/",
+    { uri: "http://downloads.com/", transition: TRANSITION_DOWNLOAD },
+  ];
+  for (let url of arrayOfURLsToVisit) {
+    await PlacesTestUtils.addVisits(url);
+  }
+
+  // Get all URLs.
+  let allURLs = await PlacesSyncUtils.history.getAllURLs({
+    since: new Date(Date.now() - 2592000000),
+    limit: 5000,
+  });
+
+  // Should be only the non-download
+  equal(allURLs.length, 1, "Should only get one URL back.");
+
+  // Check that the correct URLs were retrived.
+  equal(allURLs[0], arrayOfURLsToVisit[0], "Should get back our non-download.");
+
+  // Remove the visits added during this test.
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_order() {
+  info("Insert some bookmarks");
+  let guids = await populateTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      kind: "bookmark",
+      title: "childBmk",
+      url: "http://getfirefox.com",
+    },
+    {
+      kind: "bookmark",
+      title: "siblingBmk",
+      url: "http://getthunderbird.com",
+    },
+    {
+      kind: "folder",
+      title: "siblingFolder",
+    },
+    {
+      kind: "separator",
+      title: "siblingSep",
+    }
+  );
+
+  info("Reorder inserted bookmarks");
+  {
+    let order = [
+      guids.siblingFolder,
+      guids.siblingSep,
+      guids.childBmk,
+      guids.siblingBmk,
+    ];
+    await PlacesSyncUtils.bookmarks.order(
+      PlacesUtils.bookmarks.menuGuid,
+      order
+    );
+    let childRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+      PlacesUtils.bookmarks.menuGuid
+    );
+    deepEqual(
+      childRecordIds,
+      order,
+      "New bookmarks should be reordered according to array"
+    );
+  }
+
+  info("Same order with unspecified children");
+  {
+    await PlacesSyncUtils.bookmarks.order(PlacesUtils.bookmarks.menuGuid, [
+      guids.siblingSep,
+      guids.siblingBmk,
+    ]);
+    let childRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+      PlacesUtils.bookmarks.menuGuid
+    );
+    deepEqual(
+      childRecordIds,
+      [guids.siblingFolder, guids.siblingSep, guids.childBmk, guids.siblingBmk],
+      "Current order should be respected if possible"
+    );
+  }
+
+  info("New order with unspecified children");
+  {
+    await PlacesSyncUtils.bookmarks.order(PlacesUtils.bookmarks.menuGuid, [
+      guids.siblingBmk,
+      guids.siblingSep,
+    ]);
+    let childRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+      PlacesUtils.bookmarks.menuGuid
+    );
+    deepEqual(
+      childRecordIds,
+      [guids.siblingBmk, guids.siblingSep, guids.siblingFolder, guids.childBmk],
+      "Unordered children should be moved to end if current order can't be respected"
+    );
+  }
+
+  info("Reorder with nonexistent children");
+  {
+    await PlacesSyncUtils.bookmarks.order(PlacesUtils.bookmarks.menuGuid, [
+      guids.childBmk,
+      makeGuid(),
+      guids.siblingBmk,
+      guids.siblingSep,
+      makeGuid(),
+      guids.siblingFolder,
+      makeGuid(),
+    ]);
+    let childRecordIds = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+      PlacesUtils.bookmarks.menuGuid
+    );
+    deepEqual(
+      childRecordIds,
+      [guids.childBmk, guids.siblingBmk, guids.siblingSep, guids.siblingFolder],
+      "Nonexistent children should be ignored"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_order_roots() {
+  let oldOrder = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+    PlacesUtils.bookmarks.rootGuid
+  );
+  await PlacesSyncUtils.bookmarks.order(
+    PlacesUtils.bookmarks.rootGuid,
+    shuffle(oldOrder)
+  );
+  let newOrder = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+    PlacesUtils.bookmarks.rootGuid
+  );
+  deepEqual(oldOrder, newOrder, "Should ignore attempts to reorder roots");
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_tags() {
+  await ignoreChangedRoots();
+
+  info("Insert untagged items with same URL");
+  let firstItem = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    url: "https://example.org",
+  });
+  let secondItem = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    url: "https://example.org",
+  });
+  let untaggedItem = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    url: "https://bugzilla.org",
+  });
+  let taggedItem = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    url: "https://mozilla.org",
+  });
+
+  info("Create tag");
+  PlacesUtils.tagging.tagURI(uri("https://example.org"), ["taggy"]);
+
+  let tagBm = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.tagsGuid,
+    index: 0,
+  });
+  let tagFolderGuid = tagBm.guid;
+  let tagFolderId = await PlacesTestUtils.promiseItemId(tagFolderGuid);
+
+  info("Tagged bookmarks should be in changeset");
+  {
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId].sort(),
+      "Should include tagged bookmarks in changeset"
+    );
+    await setChangesSynced(changes);
+  }
+
+  info("Change tag case");
+  {
+    PlacesUtils.tagging.tagURI(uri("https://mozilla.org"), ["TaGgY"]);
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId, taggedItem.recordId].sort(),
+      "Should include tagged bookmarks after changing case"
+    );
+    await assertTagForURLs(
+      "TaGgY",
+      ["https://example.org/", "https://mozilla.org/"],
+      "Should add tag for new URL"
+    );
+    await setChangesSynced(changes);
+  }
+
+  // These tests change a tag item directly, without going through the tagging
+  // service. This behavior isn't supported, but the tagging service registers
+  // an observer to handle these cases, so we make sure we handle them
+  // correctly.
+
+  info("Rename tag folder using Bookmarks.setItemTitle");
+  {
+    PlacesUtils.bookmarks.setItemTitle(tagFolderId, "sneaky");
+    deepEqual(
+      (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+      ["sneaky"],
+      "Tagging service should update cache with new title"
+    );
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId].sort(),
+      "Should include tagged bookmarks after renaming tag folder"
+    );
+    await setChangesSynced(changes);
+  }
+
+  info("Rename tag folder using Bookmarks.update");
+  {
+    await PlacesUtils.bookmarks.update({
+      guid: tagFolderGuid,
+      title: "tricky",
+    });
+    deepEqual(
+      (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+      ["tricky"],
+      "Tagging service should update cache after updating tag folder"
+    );
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId].sort(),
+      "Should include tagged bookmarks after updating tag folder"
+    );
+    await setChangesSynced(changes);
+  }
+
+  info("Change tag entry URL using Bookmarks.update");
+  {
+    let bm = await PlacesUtils.bookmarks.fetch({
+      parentGuid: tagFolderGuid,
+      index: 0,
+    });
+    bm.url = "https://bugzilla.org/";
+    await PlacesUtils.bookmarks.update(bm);
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId, untaggedItem.recordId].sort(),
+      "Should include tagged bookmarks after changing tag entry URI"
+    );
+    await assertTagForURLs(
+      "tricky",
+      ["https://bugzilla.org/", "https://mozilla.org/"],
+      "Should remove tag entry for old URI"
+    );
+    await setChangesSynced(changes);
+
+    bm.url = "https://example.org/";
+    await PlacesUtils.bookmarks.update(bm);
+    changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [firstItem.recordId, secondItem.recordId, untaggedItem.recordId].sort(),
+      "Should include tagged bookmarks after changing tag entry URL"
+    );
+    await assertTagForURLs(
+      "tricky",
+      ["https://example.org/", "https://mozilla.org/"],
+      "Should remove tag entry for old URL"
+    );
+    await setChangesSynced(changes);
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_conflicting_keywords() {
+  await ignoreChangedRoots();
+
+  info("Insert bookmark with new keyword");
+  let tbBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "unfiled",
+    url: "http://getthunderbird.com",
+    keyword: "tbird",
+  });
+  {
+    let entryByKeyword = await PlacesUtils.keywords.fetch("tbird");
+    equal(
+      entryByKeyword.url.href,
+      "http://getthunderbird.com/",
+      "Should return new keyword entry by URL"
+    );
+    let entryByURL = await PlacesUtils.keywords.fetch({
+      url: "http://getthunderbird.com",
+    });
+    equal(entryByURL.keyword, "tbird", "Should return new entry by keyword");
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      changes,
+      {},
+      "Should not bump change counter for new keyword entry"
+    );
+  }
+
+  info("Insert bookmark with same URL and different keyword");
+  let dupeTbBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    recordId: makeGuid(),
+    parentRecordId: "toolbar",
+    url: "http://getthunderbird.com",
+    keyword: "tb",
+  });
+  {
+    let oldKeywordByURL = await PlacesUtils.keywords.fetch("tbird");
+    ok(
+      !oldKeywordByURL,
+      "Should remove old entry when inserting bookmark with different keyword"
+    );
+    let entryByKeyword = await PlacesUtils.keywords.fetch("tb");
+    equal(
+      entryByKeyword.url.href,
+      "http://getthunderbird.com/",
+      "Should return different keyword entry by URL"
+    );
+    let entryByURL = await PlacesUtils.keywords.fetch({
+      url: "http://getthunderbird.com",
+    });
+    equal(entryByURL.keyword, "tb", "Should return different entry by keyword");
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [tbBmk.recordId, dupeTbBmk.recordId].sort(),
+      "Should bump change counter for bookmarks with different keyword"
+    );
+    await setChangesSynced(changes);
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_insert() {
+  info("Insert bookmark");
+  {
+    let item = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "bookmark",
+      recordId: makeGuid(),
+      parentRecordId: "menu",
+      url: "https://example.org",
+    });
+    let { type } = await PlacesUtils.bookmarks.fetch({ guid: item.recordId });
+    equal(
+      type,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      "Bookmark should have correct type"
+    );
+  }
+
+  info("Insert query");
+  {
+    let item = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "query",
+      recordId: makeGuid(),
+      parentRecordId: "menu",
+      url: "place:terms=term&folder=TOOLBAR&queryType=1",
+      folder: "Saved search",
+    });
+    let { type } = await PlacesUtils.bookmarks.fetch({ guid: item.recordId });
+    equal(
+      type,
+      PlacesUtils.bookmarks.TYPE_BOOKMARK,
+      "Queries should be stored as bookmarks"
+    );
+  }
+
+  info("Insert folder");
+  {
+    let item = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "folder",
+      recordId: makeGuid(),
+      parentRecordId: "menu",
+      title: "New folder",
+    });
+    let { type } = await PlacesUtils.bookmarks.fetch({ guid: item.recordId });
+    equal(
+      type,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      "Folder should have correct type"
+    );
+  }
+
+  info("Insert separator");
+  {
+    let item = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "separator",
+      recordId: makeGuid(),
+      parentRecordId: "menu",
+    });
+    let { type } = await PlacesUtils.bookmarks.fetch({ guid: item.recordId });
+    equal(
+      type,
+      PlacesUtils.bookmarks.TYPE_SEPARATOR,
+      "Separator should have correct type"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_insert_tags() {
+  await Promise.all(
+    [
+      {
+        kind: "bookmark",
+        url: "https://example.com",
+        recordId: makeGuid(),
+        parentRecordId: "menu",
+        tags: ["foo", "bar"],
+      },
+      {
+        kind: "bookmark",
+        url: "https://example.org",
+        recordId: makeGuid(),
+        parentRecordId: "toolbar",
+        tags: ["foo", "baz"],
+      },
+      {
+        kind: "query",
+        url: "place:queryType=1&sort=12&maxResults=10",
+        recordId: makeGuid(),
+        parentRecordId: "toolbar",
+        folder: "bar",
+        tags: ["baz", "qux"],
+        title: "bar",
+      },
+    ].map(info => PlacesSyncUtils.test.bookmarks.insert(info))
+  );
+
+  await assertTagForURLs(
+    "foo",
+    ["https://example.com/", "https://example.org/"],
+    "2 URLs with new tag"
+  );
+  await assertTagForURLs(
+    "bar",
+    ["https://example.com/"],
+    "1 URL with existing tag"
+  );
+  await assertTagForURLs(
+    "baz",
+    ["https://example.org/", "place:queryType=1&sort=12&maxResults=10"],
+    "Should support tagging URLs and tag queries"
+  );
+  await assertTagForURLs(
+    "qux",
+    ["place:queryType=1&sort=12&maxResults=10"],
+    "Should support tagging tag queries"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_insert_tags_whitespace() {
+  info("Untrimmed and blank tags");
+  let taggedBlanks = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    url: "https://example.org",
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    tags: [" untrimmed ", " ", "taggy"],
+  });
+  deepEqual(
+    taggedBlanks.tags,
+    ["untrimmed", "taggy"],
+    "Should not return empty tags"
+  );
+  assertURLHasTags(
+    "https://example.org/",
+    ["taggy", "untrimmed"],
+    "Should set trimmed tags and ignore dupes"
+  );
+
+  info("Dupe tags");
+  let taggedDupes = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    url: "https://example.net",
+    recordId: makeGuid(),
+    parentRecordId: "toolbar",
+    tags: [" taggy", "taggy ", " taggy ", "taggy"],
+  });
+  deepEqual(
+    taggedDupes.tags,
+    ["taggy", "taggy", "taggy", "taggy"],
+    "Should return trimmed and dupe tags"
+  );
+  assertURLHasTags(
+    "https://example.net/",
+    ["taggy"],
+    "Should ignore dupes when setting tags"
+  );
+
+  await assertTagForURLs(
+    "taggy",
+    ["https://example.net/", "https://example.org/"],
+    "Should exclude falsy tags"
+  );
+
+  PlacesUtils.tagging.untagURI(uri("https://example.org"), [
+    "untrimmed",
+    "taggy",
+  ]);
+  PlacesUtils.tagging.untagURI(uri("https://example.net"), ["taggy"]);
+  deepEqual(
+    (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+    [],
+    "Should clean up all tags"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_insert_keyword() {
+  info("Insert item with new keyword");
+  {
+    await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "bookmark",
+      parentRecordId: "menu",
+      url: "https://example.com",
+      keyword: "moz",
+      recordId: makeGuid(),
+    });
+    let entry = await PlacesUtils.keywords.fetch("moz");
+    equal(
+      entry.url.href,
+      "https://example.com/",
+      "Should add keyword for item"
+    );
+  }
+
+  info("Insert item with existing keyword");
+  {
+    await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "bookmark",
+      parentRecordId: "menu",
+      url: "https://mozilla.org",
+      keyword: "moz",
+      recordId: makeGuid(),
+    });
+    let entry = await PlacesUtils.keywords.fetch("moz");
+    equal(
+      entry.url.href,
+      "https://mozilla.org/",
+      "Should reassign keyword to new item"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_insert_tag_query() {
+  info("Use the public tagging API to ensure we added the tag correctly");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    url: "https://mozilla.org",
+    title: "Mozilla",
+  });
+  PlacesUtils.tagging.tagURI(uri("https://mozilla.org"), ["taggy"]);
+  assertURLHasTags(
+    "https://mozilla.org/",
+    ["taggy"],
+    "Should set tags using the tagging API"
+  );
+
+  info("Insert tag query for non existing tag");
+  {
+    let query = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "query",
+      recordId: makeGuid(),
+      parentRecordId: "toolbar",
+      url: "place:type=7&folder=90",
+      folder: "nonexisting",
+      title: "Tagged stuff",
+    });
+    let params = new URLSearchParams(query.url.pathname);
+    ok(!params.has("type"), "Should not preserve query type");
+    ok(!params.has("folder"), "Should not preserve folder");
+    equal(params.get("tag"), "nonexisting", "Should add tag");
+    deepEqual(
+      (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+      ["taggy"],
+      "The nonexisting tag should not be added"
+    );
+  }
+
+  info("Insert tag query for existing tag");
+  {
+    let url = "place:type=7&folder=90&maxResults=15";
+    let query = await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "query",
+      recordId: makeGuid(),
+      parentRecordId: "menu",
+      url,
+      folder: "taggy",
+      title: "Sorted and tagged",
+    });
+    let params = new URLSearchParams(query.url.pathname);
+    ok(!params.get("type"), "Should not preserve query type");
+    ok(!params.has("folder"), "Should not preserve folder");
+    equal(params.get("maxResults"), "15", "Should preserve additional params");
+    equal(params.get("tag"), "taggy", "Should add tag");
+    deepEqual(
+      (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+      ["taggy"],
+      "Should not duplicate existing tags"
+    );
+  }
+
+  info("Removing the tag should clean up the tag folder");
+  PlacesUtils.tagging.untagURI(uri("https://mozilla.org"), null);
+  deepEqual(
+    (await PlacesUtils.bookmarks.fetchTags()).map(t => t.name),
+    [],
+    "Should remove tag folder once last item is untagged"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_fetch() {
+  let folder = await PlacesSyncUtils.test.bookmarks.insert({
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    kind: "folder",
+  });
+  let bmk = await PlacesSyncUtils.test.bookmarks.insert({
+    recordId: makeGuid(),
+    parentRecordId: "menu",
+    kind: "bookmark",
+    url: "https://example.com",
+    tags: ["taggy"],
+  });
+  let folderBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    recordId: makeGuid(),
+    parentRecordId: folder.recordId,
+    kind: "bookmark",
+    url: "https://example.org",
+    keyword: "kw",
+  });
+  let folderSep = await PlacesSyncUtils.test.bookmarks.insert({
+    recordId: makeGuid(),
+    parentRecordId: folder.recordId,
+    kind: "separator",
+  });
+  let tagQuery = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "query",
+    recordId: makeGuid(),
+    parentRecordId: "toolbar",
+    url: "place:tag=taggy",
+    folder: "taggy",
+    title: "Tagged stuff",
+  });
+
+  info("Fetch empty folder");
+  {
+    let item = await PlacesSyncUtils.bookmarks.fetch(folder.recordId);
+    deepEqual(
+      item,
+      {
+        recordId: folder.recordId,
+        kind: "folder",
+        parentRecordId: "menu",
+        childRecordIds: [folderBmk.recordId, folderSep.recordId],
+        parentTitle: "menu",
+        dateAdded: item.dateAdded,
+        title: "",
+      },
+      "Should include children, title, and parent title in folder"
+    );
+  }
+
+  info("Fetch bookmark with tags");
+  {
+    let item = await PlacesSyncUtils.bookmarks.fetch(bmk.recordId);
+    deepEqual(
+      Object.keys(item).sort(),
+      [
+        "recordId",
+        "kind",
+        "parentRecordId",
+        "url",
+        "tags",
+        "parentTitle",
+        "title",
+        "dateAdded",
+      ].sort(),
+      "Should include bookmark-specific properties"
+    );
+    equal(item.recordId, bmk.recordId, "Sync ID should match");
+    equal(item.url.href, "https://example.com/", "Should return URL");
+    equal(item.parentRecordId, "menu", "Should return parent sync ID");
+    deepEqual(item.tags, ["taggy"], "Should return tags");
+    equal(item.parentTitle, "menu", "Should return parent title");
+    strictEqual(item.title, "", "Should return empty title");
+  }
+
+  info("Fetch bookmark with keyword; without parent title");
+  {
+    let item = await PlacesSyncUtils.bookmarks.fetch(folderBmk.recordId);
+    deepEqual(
+      Object.keys(item).sort(),
+      [
+        "recordId",
+        "kind",
+        "parentRecordId",
+        "url",
+        "keyword",
+        "tags",
+        "parentTitle",
+        "title",
+        "dateAdded",
+      ].sort(),
+      "Should omit blank bookmark-specific properties"
+    );
+    deepEqual(item.tags, [], "Tags should be empty");
+    equal(item.keyword, "kw", "Should return keyword");
+    strictEqual(
+      item.parentTitle,
+      "",
+      "Should include parent title even if empty"
+    );
+    strictEqual(item.title, "", "Should include bookmark title even if empty");
+  }
+
+  info("Fetch separator");
+  {
+    let item = await PlacesSyncUtils.bookmarks.fetch(folderSep.recordId);
+    strictEqual(item.index, 1, "Should return separator position");
+  }
+
+  info("Fetch tag query");
+  {
+    let item = await PlacesSyncUtils.bookmarks.fetch(tagQuery.recordId);
+    deepEqual(
+      Object.keys(item).sort(),
+      [
+        "recordId",
+        "kind",
+        "parentRecordId",
+        "url",
+        "title",
+        "folder",
+        "parentTitle",
+        "dateAdded",
+      ].sort(),
+      "Should include query-specific properties"
+    );
+    equal(
+      item.url.href,
+      `place:tag=taggy`,
+      "Should not rewrite outgoing tag queries"
+    );
+    equal(item.folder, "taggy", "Should return tag name for tag queries");
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_new_parent() {
+  await ignoreChangedRoots();
+
+  let { syncedGuids, unsyncedFolder } =
+    await moveSyncedBookmarksToUnsyncedParent();
+
+  info("Unsynced parent and synced items should be tracked");
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(changes).sort(),
+    [
+      syncedGuids.folder,
+      syncedGuids.topBmk,
+      syncedGuids.childBmk,
+      unsyncedFolder.guid,
+      "menu",
+    ].sort(),
+    "Should return change records for moved items and new parent"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_deleted_folder() {
+  await ignoreChangedRoots();
+
+  let { syncedGuids, unsyncedFolder } =
+    await moveSyncedBookmarksToUnsyncedParent();
+
+  info("Remove unsynced new folder");
+  await PlacesUtils.bookmarks.remove(unsyncedFolder.guid);
+
+  info("Deleted synced items should be tracked; unsynced folder should not");
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(changes).sort(),
+    [
+      syncedGuids.folder,
+      syncedGuids.topBmk,
+      syncedGuids.childBmk,
+      "menu",
+    ].sort(),
+    "Should return change records for all deleted items"
+  );
+  for (let guid of Object.values(syncedGuids)) {
+    strictEqual(
+      changes[guid].tombstone,
+      true,
+      `Tombstone flag should be set for deleted item ${guid}`
+    );
+    equal(
+      changes[guid].counter,
+      1,
+      `Change counter should be 1 for deleted item ${guid}`
+    );
+    equal(
+      changes[guid].status,
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      `Sync status should be normal for deleted item ${guid}`
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_import_html() {
+  await ignoreChangedRoots();
+
+  info("Add unsynced bookmark");
+  let unsyncedBmk = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "https://example.com",
+  });
+
+  {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      unsyncedBmk.guid
+    );
+    ok(
+      fields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+      ),
+      "Unsynced bookmark statuses should match"
+    );
+  }
+
+  info("Import new bookmarks from HTML");
+  let { path } = do_get_file("./sync_utils_bookmarks.html");
+  await BookmarkHTMLUtils.importFromFile(path);
+
+  // Bookmarks.html doesn't store IDs, so we need to look these up.
+  let mozBmk = await PlacesUtils.bookmarks.fetch({
+    url: "https://www.mozilla.org/",
+  });
+  let fxBmk = await PlacesUtils.bookmarks.fetch({
+    url: "https://www.mozilla.org/en-US/firefox/",
+  });
+  // All Bookmarks.html bookmarks are stored under the menu. For toolbar
+  // bookmarks, this means they're imported into a "Bookmarks Toolbar"
+  // subfolder under the menu, instead of the real toolbar root.
+  let toolbarSubfolder = (
+    await PlacesUtils.bookmarks.search({
+      title: "Bookmarks Toolbar",
+    })
+  ).find(item => item.guid != PlacesUtils.bookmarks.toolbarGuid);
+  let importedFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    mozBmk.guid,
+    fxBmk.guid,
+    toolbarSubfolder.guid
+  );
+  ok(
+    importedFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Sync statuses should match for HTML imports"
+  );
+
+  info("Fetch new HTML imports");
+  let newChanges = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(newChanges).sort(),
+    [
+      mozBmk.guid,
+      fxBmk.guid,
+      toolbarSubfolder.guid,
+      "menu",
+      unsyncedBmk.guid,
+    ].sort(),
+    "Should return new IDs imported from HTML file"
+  );
+  let newFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    unsyncedBmk.guid,
+    mozBmk.guid,
+    fxBmk.guid,
+    toolbarSubfolder.guid
+  );
+  ok(
+    newFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Pulling new HTML imports should not mark them as syncing"
+  );
+
+  info("Mark new HTML imports as syncing");
+  await PlacesSyncUtils.bookmarks.markChangesAsSyncing(newChanges);
+  let normalFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    unsyncedBmk.guid,
+    mozBmk.guid,
+    fxBmk.guid,
+    toolbarSubfolder.guid
+  );
+  ok(
+    normalFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    ),
+    "Marking new HTML imports as syncing should update their statuses"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_import_json() {
+  await ignoreChangedRoots();
+
+  info("Add synced folder");
+  let syncedFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "syncedFolder",
+  });
+  await PlacesTestUtils.setBookmarkSyncFields({
+    guid: syncedFolder.guid,
+    syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+  });
+
+  info("Import new bookmarks from JSON");
+  let { path } = do_get_file("./sync_utils_bookmarks.json");
+  await BookmarkJSONUtils.importFromFile(path);
+  {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      syncedFolder.guid,
+      "NnvGl3CRA4hC",
+      "APzP8MupzA8l"
+    );
+    deepEqual(
+      fields.map(field => field.syncStatus),
+      [
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      ],
+      "Sync statuses should match for JSON imports"
+    );
+  }
+
+  info("Fetch new JSON imports");
+  let newChanges = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(newChanges).sort(),
+    [
+      "NnvGl3CRA4hC",
+      "APzP8MupzA8l",
+      "menu",
+      "toolbar",
+      syncedFolder.guid,
+    ].sort(),
+    "Should return items imported from JSON backup"
+  );
+  let existingFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    syncedFolder.guid,
+    "NnvGl3CRA4hC",
+    "APzP8MupzA8l"
+  );
+  deepEqual(
+    existingFields.map(field => field.syncStatus),
+    [
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+      PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+    ],
+    "Pulling new JSON imports should not mark them as syncing"
+  );
+
+  info("Mark new JSON imports as syncing");
+  await PlacesSyncUtils.bookmarks.markChangesAsSyncing(newChanges);
+  let normalFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    syncedFolder.guid,
+    "NnvGl3CRA4hC",
+    "APzP8MupzA8l"
+  );
+  ok(
+    normalFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    ),
+    "Marking new JSON imports as syncing should update their statuses"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_restore_json_tracked() {
+  await ignoreChangedRoots();
+
+  let unsyncedBmk = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "https://example.com",
+  });
+  info(`Unsynced bookmark GUID: ${unsyncedBmk.guid}`);
+  let syncedFolder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "syncedFolder",
+  });
+  info(`Synced folder GUID: ${syncedFolder.guid}`);
+  await PlacesTestUtils.setBookmarkSyncFields({
+    guid: syncedFolder.guid,
+    syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+  });
+  {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      unsyncedBmk.guid,
+      syncedFolder.guid
+    );
+    deepEqual(
+      fields.map(field => field.syncStatus),
+      [
+        PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      ],
+      "Sync statuses should match before restoring from JSON"
+    );
+  }
+
+  info("Restore from JSON, replacing existing items");
+  let { path } = do_get_file("./sync_utils_bookmarks.json");
+  await BookmarkJSONUtils.importFromFile(path, { replace: true });
+  {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      "NnvGl3CRA4hC",
+      "APzP8MupzA8l"
+    );
+    ok(
+      fields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+      ),
+      "All bookmarks should be NEW after restoring from JSON"
+    );
+  }
+
+  info("Fetch new items restored from JSON");
+  {
+    let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+    deepEqual(
+      Object.keys(changes).sort(),
+      [
+        "menu",
+        "toolbar",
+        "unfiled",
+        "mobile",
+        "NnvGl3CRA4hC",
+        "APzP8MupzA8l",
+      ].sort(),
+      "Should restore items from JSON backup"
+    );
+
+    let existingFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+      PlacesUtils.bookmarks.mobileGuid,
+      "NnvGl3CRA4hC",
+      "APzP8MupzA8l"
+    );
+    ok(
+      existingFields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+      ),
+      "Items restored from JSON backup should not be marked as syncing"
+    );
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones,
+      [],
+      "Tombstones should not exist after restoring from JSON backup"
+    );
+
+    await PlacesSyncUtils.bookmarks.markChangesAsSyncing(changes);
+    let normalFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+      "NnvGl3CRA4hC",
+      "APzP8MupzA8l"
+    );
+    ok(
+      normalFields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+      ),
+      "Roots and NEW items restored from JSON backup should be marked as NORMAL"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pullChanges_tombstones() {
+  await ignoreChangedRoots();
+
+  info("Insert new bookmarks");
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        url: "http://example.com/a",
+        title: "A",
+      },
+      {
+        guid: "bookmarkBBBB",
+        url: "http://example.com/b",
+        title: "B",
+      },
+    ],
+  });
+
+  info("Manually insert conflicting tombstone for new bookmark");
+  await PlacesUtils.withConnectionWrapper(
+    "test_pullChanges_tombstones",
+    async function (db) {
+      await db.executeCached(
+        `
+        INSERT INTO moz_bookmarks_deleted(guid)
+        VALUES(:guid)`,
+        { guid: "bookmarkAAAA" }
+      );
+    }
+  );
+
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(changes).sort(),
+    ["bookmarkAAAA", "bookmarkBBBB", "menu"],
+    "Should handle undeleted items when returning changes"
+  );
+  strictEqual(
+    changes.bookmarkAAAA.tombstone,
+    false,
+    "Should replace tombstone for A with undeleted item"
+  );
+  strictEqual(
+    changes.bookmarkBBBB.tombstone,
+    false,
+    "Should not report B as deleted"
+  );
+
+  await setChangesSynced(changes);
+
+  let newChanges = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    newChanges,
+    {},
+    "Should not return changes after marking undeleted items as synced"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_pushChanges() {
+  await ignoreChangedRoots();
+
+  info("Populate test bookmarks");
+  let guids = await populateTree(
+    PlacesUtils.bookmarks.menuGuid,
+    {
+      kind: "bookmark",
+      title: "unknownBmk",
+      url: "https://example.org",
+    },
+    {
+      kind: "bookmark",
+      title: "syncedBmk",
+      url: "https://example.com",
+    },
+    {
+      kind: "bookmark",
+      title: "newBmk",
+      url: "https://example.info",
+    },
+    {
+      kind: "bookmark",
+      title: "deletedBmk",
+      url: "https://example.edu",
+    },
+    {
+      kind: "bookmark",
+      title: "unchangedBmk",
+      url: "https://example.systems",
+    }
+  );
+
+  info("Update sync statuses");
+  await PlacesTestUtils.setBookmarkSyncFields(
+    {
+      guid: guids.syncedBmk,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    },
+    {
+      guid: guids.unknownBmk,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN,
+    },
+    {
+      guid: guids.deletedBmk,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    },
+    {
+      guid: guids.unchangedBmk,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      syncChangeCounter: 0,
+    }
+  );
+
+  info("Change synced bookmark; should bump change counter");
+  await PlacesUtils.bookmarks.update({
+    guid: guids.syncedBmk,
+    url: "https://example.ninja",
+  });
+
+  info("Remove synced bookmark");
+  {
+    await PlacesUtils.bookmarks.remove(guids.deletedBmk);
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    ok(
+      tombstones.some(({ guid }) => guid == guids.deletedBmk),
+      "Should write tombstone for deleted synced bookmark"
+    );
+  }
+
+  info("Pull changes");
+  let totalSyncChanges = PlacesUtils.bookmarks.totalSyncChanges;
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  {
+    let actualChanges = Object.entries(changes).map(([recordId, change]) => ({
+      recordId,
+      syncChangeCounter: change.counter,
+    }));
+    let expectedChanges = [
+      {
+        recordId: guids.unknownBmk,
+        syncChangeCounter: 1,
+      },
+      {
+        // Parent of changed bookmarks.
+        recordId: "menu",
+        syncChangeCounter: 6,
+      },
+      {
+        recordId: guids.syncedBmk,
+        syncChangeCounter: 2,
+      },
+      {
+        recordId: guids.newBmk,
+        syncChangeCounter: 1,
+      },
+      {
+        recordId: guids.deletedBmk,
+        syncChangeCounter: 1,
+      },
+    ];
+    deepEqual(
+      sortBy(actualChanges, "recordId"),
+      sortBy(expectedChanges, "recordId"),
+      "Should return deleted, new, and unknown bookmarks"
+    );
+  }
+
+  info("Modify changed bookmark to bump its counter");
+  await PlacesUtils.bookmarks.update({
+    guid: guids.newBmk,
+    url: "https://example.club",
+  });
+
+  info("Mark some bookmarks as synced");
+  for (let title of ["unknownBmk", "newBmk", "deletedBmk"]) {
+    let guid = guids[title];
+    strictEqual(
+      changes[guid].synced,
+      false,
+      "All bookmarks should not be marked as synced yet"
+    );
+    changes[guid].synced = true;
+  }
+
+  await PlacesSyncUtils.bookmarks.pushChanges(changes);
+  equal(PlacesUtils.bookmarks.totalSyncChanges, totalSyncChanges + 4);
+
+  {
+    let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      guids.newBmk,
+      guids.unknownBmk
+    );
+    ok(
+      fields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+      ),
+      "Should update sync statuses for synced bookmarks"
+    );
+  }
+
+  {
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    ok(
+      !tombstones.some(({ guid }) => guid == guids.deletedBmk),
+      "Should remove tombstone after syncing"
+    );
+
+    let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      guids.unknownBmk,
+      guids.syncedBmk,
+      guids.newBmk
+    );
+    {
+      let info = syncFields.find(field => field.guid == guids.unknownBmk);
+      equal(
+        info.syncStatus,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        "Syncing an UNKNOWN bookmark should set its sync status to NORMAL"
+      );
+      strictEqual(
+        info.syncChangeCounter,
+        0,
+        "Syncing an UNKNOWN bookmark should reduce its change counter"
+      );
+    }
+    {
+      let info = syncFields.find(field => field.guid == guids.syncedBmk);
+      equal(
+        info.syncStatus,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        "Syncing a NORMAL bookmark should not update its sync status"
+      );
+      equal(
+        info.syncChangeCounter,
+        2,
+        "Should not reduce counter for NORMAL bookmark not marked as synced"
+      );
+    }
+    {
+      let info = syncFields.find(field => field.guid == guids.newBmk);
+      equal(
+        info.syncStatus,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        "Syncing a NEW bookmark should update its sync status"
+      );
+      strictEqual(
+        info.syncChangeCounter,
+        1,
+        "Updating new bookmark after pulling changes should bump change counter"
+      );
+    }
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_changes_between_pull_and_push() {
+  await ignoreChangedRoots();
+
+  info("Populate test bookmarks");
+  let guids = await populateTree(PlacesUtils.bookmarks.menuGuid, {
+    kind: "bookmark",
+    title: "bmk",
+    url: "https://example.info",
+  });
+
+  info("Update sync statuses");
+  await PlacesTestUtils.setBookmarkSyncFields({
+    guid: guids.bmk,
+    syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    syncChangeCounter: 1,
+  });
+
+  info("Pull changes");
+  let totalSyncChanges = PlacesUtils.bookmarks.totalSyncChanges;
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  Assert.equal(changes[guids.bmk].counter, 1);
+  Assert.equal(changes[guids.bmk].tombstone, false);
+
+  // delete the bookmark.
+  await PlacesUtils.bookmarks.remove(guids.bmk);
+
+  info("Push changes");
+  await PlacesSyncUtils.bookmarks.pushChanges(changes);
+  equal(PlacesUtils.bookmarks.totalSyncChanges, totalSyncChanges + 2);
+
+  // we should have a tombstone.
+  let ts = await PlacesTestUtils.fetchSyncTombstones();
+  Assert.equal(ts.length, 1);
+  Assert.equal(ts[0].guid, guids.bmk);
+
+  // there should be no record for the item we deleted.
+  Assert.strictEqual(await PlacesUtils.bookmarks.fetch(guids.bmk), null);
+
+  // and re-fetching changes should list it as a tombstone.
+  changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  Assert.equal(changes[guids.bmk].counter, 1);
+  Assert.equal(changes[guids.bmk].tombstone, true);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_separator() {
+  await ignoreChangedRoots();
+
+  await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: "menu",
+    recordId: makeGuid(),
+    url: "https://example.com",
+  });
+  let childBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: "menu",
+    recordId: makeGuid(),
+    url: "https://foo.bar",
+  });
+  let separatorRecordId = makeGuid();
+  let separator = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "separator",
+    parentRecordId: "menu",
+    recordId: separatorRecordId,
+  });
+  await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: "menu",
+    recordId: makeGuid(),
+    url: "https://bar.foo",
+  });
+
+  let child2Guid = await PlacesSyncUtils.bookmarks.recordIdToGuid(
+    childBmk.recordId
+  );
+  let parentGuid = await await PlacesSyncUtils.bookmarks.recordIdToGuid("menu");
+  let separatorGuid =
+    PlacesSyncUtils.bookmarks.recordIdToGuid(separatorRecordId);
+
+  info("Move a bookmark around the separator");
+  await PlacesUtils.bookmarks.update({
+    guid: child2Guid,
+    parentGuid,
+    index: 2,
+  });
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(Object.keys(changes).sort(), [separator.recordId, "menu"].sort());
+
+  await setChangesSynced(changes);
+
+  info("Move a separator around directly");
+  await PlacesUtils.bookmarks.update({
+    guid: separatorGuid,
+    parentGuid,
+    index: 0,
+  });
+
+  changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(Object.keys(changes).sort(), [separator.recordId, "menu"].sort());
+
+  await setChangesSynced(changes);
+
+  info("Move a separator around directly using update");
+  await PlacesUtils.bookmarks.update({ guid: separatorGuid, index: 2 });
+  changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(Object.keys(changes).sort(), [separator.recordId, "menu"].sort());
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_remove() {
+  await ignoreChangedRoots();
+
+  info("Insert subtree for removal");
+  let parentFolder = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "folder",
+    parentRecordId: "menu",
+    recordId: makeGuid(),
+  });
+  let childBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.com",
+  });
+  let childFolder = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "folder",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+  });
+  let grandChildBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: childFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.edu",
+  });
+
+  info("Remove entire subtree");
+  await PlacesSyncUtils.bookmarks.remove([
+    parentFolder.recordId,
+    childFolder.recordId,
+    childBmk.recordId,
+    grandChildBmk.recordId,
+  ]);
+
+  /**
+   * Even though we've removed the entire subtree, we still track the menu
+   * because we 1) removed `parentFolder`, 2) reparented `childFolder` to
+   * `menu`, and 3) removed `childFolder`.
+   *
+   * This depends on the order of the folders passed to `remove`. If we
+   * removed `childFolder` *before* `parentFolder`, we wouldn't reparent
+   * anything to `menu`.
+   *
+   * `deleteSyncedFolder` could check if it's reparenting an item that will
+   * eventually be removed, and avoid bumping the new parent's change counter.
+   * Unfortunately, that introduces inconsistencies if `deleteSyncedFolder` is
+   * interrupted by shutdown. If the server changes before the next sync,
+   * we'll never upload records for the reparented item or the new parent.
+   *
+   * Another alternative: we can try to remove folders in level order, instead
+   * of the order passed to `remove`. But that means we need a recursive query
+   * to determine the order. This is already enough of an edge case that
+   * occasionally reuploading the closest living ancestor is the simplest
+   * solution.
+   */
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(changes),
+    ["menu"],
+    "Should track closest living ancestor of removed subtree"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_remove_partial() {
+  await ignoreChangedRoots();
+
+  info("Insert subtree for partial removal");
+  let parentFolder = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "folder",
+    parentRecordId: PlacesUtils.bookmarks.menuGuid,
+    recordId: makeGuid(),
+  });
+  let prevSiblingBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.net",
+  });
+  let childBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.com",
+  });
+  let nextSiblingBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.org",
+  });
+  let childFolder = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "folder",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+  });
+  let grandChildBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://example.edu",
+  });
+  let grandChildSiblingBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: parentFolder.recordId,
+    recordId: makeGuid(),
+    url: "https://mozilla.org",
+  });
+  let grandChildFolder = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "folder",
+    parentRecordId: childFolder.recordId,
+    recordId: makeGuid(),
+  });
+  let greatGrandChildPrevSiblingBmk =
+    await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "bookmark",
+      parentRecordId: grandChildFolder.recordId,
+      recordId: makeGuid(),
+      url: "http://getfirefox.com",
+    });
+  let greatGrandChildNextSiblingBmk =
+    await PlacesSyncUtils.test.bookmarks.insert({
+      kind: "bookmark",
+      parentRecordId: grandChildFolder.recordId,
+      recordId: makeGuid(),
+      url: "http://getthunderbird.com",
+    });
+  let menuBmk = await PlacesSyncUtils.test.bookmarks.insert({
+    kind: "bookmark",
+    parentRecordId: "menu",
+    recordId: makeGuid(),
+    url: "https://example.info",
+  });
+
+  info("Remove subset of folders and items in subtree");
+  let changes = await PlacesSyncUtils.bookmarks.remove([
+    parentFolder.recordId,
+    childBmk.recordId,
+    grandChildFolder.recordId,
+    grandChildBmk.recordId,
+    childFolder.recordId,
+  ]);
+  deepEqual(
+    Object.keys(changes).sort(),
+    [
+      // Closest living ancestor.
+      "menu",
+      // Reparented bookmarks.
+      prevSiblingBmk.recordId,
+      nextSiblingBmk.recordId,
+      grandChildSiblingBmk.recordId,
+      greatGrandChildPrevSiblingBmk.recordId,
+      greatGrandChildNextSiblingBmk.recordId,
+    ].sort(),
+    "Should track reparented bookmarks and their closest living ancestor"
+  );
+
+  /**
+   * Reparented bookmarks should maintain their order relative to their
+   * siblings: `prevSiblingBmk` (0) should precede `nextSiblingBmk` (2) in the
+   * menu, and `greatGrandChildPrevSiblingBmk` (0) should precede
+   * `greatGrandChildNextSiblingBmk` (1).
+   */
+  let menuChildren = await PlacesSyncUtils.bookmarks.fetchChildRecordIds(
+    PlacesUtils.bookmarks.menuGuid
+  );
+  deepEqual(
+    menuChildren,
+    [
+      // Existing bookmark.
+      menuBmk.recordId,
+      // 1) Moved out of `parentFolder` to `menu`.
+      prevSiblingBmk.recordId,
+      nextSiblingBmk.recordId,
+      // 3) Moved out of `childFolder` to `menu`. After this step, `childFolder`
+      // is deleted.
+      grandChildSiblingBmk.recordId,
+      // 2) Moved out of `grandChildFolder` to `childFolder`, because we remove
+      // `grandChildFolder` *before* `childFolder`. After this step,
+      // `grandChildFolder` is deleted and `childFolder`'s children are
+      // `[grandChildSiblingBmk, greatGrandChildPrevSiblingBmk,
+      // greatGrandChildNextSiblingBmk]`.
+      greatGrandChildPrevSiblingBmk.recordId,
+      greatGrandChildNextSiblingBmk.recordId,
+    ],
+    "Should move descendants to closest living ancestor"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_migrateOldTrackerEntries() {
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  let unknownBmk = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://getfirefox.com",
+    title: "Get Firefox!",
+  });
+  let newBmk = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://getthunderbird.com",
+    title: "Get Thunderbird!",
+  });
+  let normalBmk = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "https://mozilla.org",
+    title: "Mozilla",
+  });
+
+  await PlacesTestUtils.setBookmarkSyncFields(
+    {
+      guid: unknownBmk.guid,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN,
+      syncChangeCounter: 0,
+    },
+    {
+      guid: normalBmk.guid,
+      syncStatus: PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+    }
+  );
+  PlacesUtils.tagging.tagURI(uri("http://getfirefox.com"), ["taggy"]);
+
+  let tombstoneRecordId = makeGuid();
+  await PlacesSyncUtils.bookmarks.migrateOldTrackerEntries([
+    {
+      recordId: normalBmk.guid,
+      modified: Date.now(),
+    },
+    {
+      recordId: tombstoneRecordId,
+      modified: 1479162463976,
+    },
+  ]);
+
+  let changes = await PlacesSyncUtils.bookmarks.pullChanges();
+  deepEqual(
+    Object.keys(changes).sort(),
+    [normalBmk.guid, tombstoneRecordId].sort(),
+    "Should return change records for migrated bookmark and tombstone"
+  );
+
+  let fields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    unknownBmk.guid,
+    newBmk.guid,
+    normalBmk.guid
+  );
+  for (let field of fields) {
+    if (field.guid == normalBmk.guid) {
+      Assert.greater(
+        field.lastModified,
+        normalBmk.lastModified,
+        `Should bump last modified date for migrated bookmark ${field.guid}`
+      );
+      equal(
+        field.syncChangeCounter,
+        1,
+        `Should bump change counter for migrated bookmark ${field.guid}`
+      );
+    } else {
+      strictEqual(
+        field.syncChangeCounter,
+        0,
+        `Should not bump change counter for ${field.guid}`
+      );
+    }
+    equal(
+      field.syncStatus,
+      PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+      `Should set sync status for ${field.guid} to NORMAL`
+    );
+  }
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones,
+    [
+      {
+        guid: tombstoneRecordId,
+        dateRemoved: new Date(1479162463976),
+      },
+    ],
+    "Should write tombstone for nonexistent migrated item"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_ensureMobileQuery() {
+  info("Ensure we correctly set the showMobileBookmarks preference");
+  const mobilePref = "browser.bookmarks.showMobileBookmarks";
+  Services.prefs.clearUserPref(mobilePref);
+
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkAAAA",
+    parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    url: "http://example.com/a",
+    title: "A",
+  });
+
+  await PlacesUtils.bookmarks.insert({
+    guid: "bookmarkBBBB",
+    parentGuid: PlacesUtils.bookmarks.mobileGuid,
+    url: "http://example.com/b",
+    title: "B",
+  });
+
+  await PlacesSyncUtils.bookmarks.ensureMobileQuery();
+
+  Assert.ok(
+    Services.prefs.getBoolPref(mobilePref),
+    "Pref should be true where there are bookmarks in the folder."
+  );
+
+  await PlacesUtils.bookmarks.remove("bookmarkAAAA");
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+
+  await PlacesSyncUtils.bookmarks.ensureMobileQuery();
+
+  Assert.ok(
+    !Services.prefs.getBoolPref(mobilePref),
+    "Pref should be false where there are no bookmarks in the folder."
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_remove_stale_tombstones() {
+  info("Insert and delete synced bookmark");
+  {
+    await PlacesUtils.bookmarks.insert({
+      guid: "bookmarkAAAA",
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      url: "http://example.com/a",
+      title: "A",
+      source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    });
+    await PlacesUtils.bookmarks.remove("bookmarkAAAA");
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones.map(({ guid }) => guid),
+      ["bookmarkAAAA"],
+      "Should store tombstone for deleted synced bookmark"
+    );
+  }
+
+  info("Reinsert deleted bookmark");
+  {
+    // Different parent, URL, and title, but same GUID.
+    await PlacesUtils.bookmarks.insert({
+      guid: "bookmarkAAAA",
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: "http://example.com/a-restored",
+      title: "A (Restored)",
+    });
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones,
+      [],
+      "Should remove tombstone for reinserted bookmark"
+    );
+  }
+
+  info("Insert tree and erase everything");
+  {
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.menuGuid,
+      source: PlacesUtils.bookmarks.SOURCES.SYNC,
+      children: [
+        {
+          guid: "bookmarkBBBB",
+          url: "http://example.com/b",
+          title: "B",
+        },
+        {
+          guid: "bookmarkCCCC",
+          url: "http://example.com/c",
+          title: "C",
+        },
+      ],
+    });
+    await PlacesUtils.bookmarks.eraseEverything();
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones.map(({ guid }) => guid).sort(),
+      ["bookmarkBBBB", "bookmarkCCCC"],
+      "Should store tombstones after erasing everything"
+    );
+  }
+
+  info("Reinsert tree");
+  {
+    await PlacesUtils.bookmarks.insertTree({
+      guid: PlacesUtils.bookmarks.mobileGuid,
+      children: [
+        {
+          guid: "bookmarkBBBB",
+          url: "http://example.com/b",
+          title: "B",
+        },
+        {
+          guid: "bookmarkCCCC",
+          url: "http://example.com/c",
+          title: "C",
+        },
+      ],
+    });
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones.map(({ guid }) => guid).sort(),
+      [],
+      "Should remove tombstones after reinserting tree"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_resetSyncId() {
+  let syncId = await PlacesSyncUtils.bookmarks.getSyncId();
+  strictEqual(syncId, "", "Should start with empty bookmarks sync ID");
+
+  // Add a tree with a NORMAL bookmark (A), tombstone (B), NEW bookmark (C),
+  // and UNKNOWN bookmark (D).
+  info("Set up local tree before resetting bookmarks sync ID");
+  await ignoreChangedRoots();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "bookmarkCCCC",
+    title: "C",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: "bookmarkDDDD",
+    title: "D",
+    url: "http://example.com/d",
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  info("Assign new bookmarks sync ID for first time");
+  let newSyncId = await PlacesSyncUtils.bookmarks.resetSyncId();
+  syncId = await PlacesSyncUtils.bookmarks.getSyncId();
+  equal(
+    newSyncId,
+    syncId,
+    "Should assign new bookmarks sync ID for first time"
+  );
+
+  let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    "bookmarkAAAA",
+    "bookmarkCCCC",
+    "bookmarkDDDD"
+  );
+  ok(
+    syncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Should change all sync statuses to NEW after resetting bookmarks sync ID"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(
+    tombstones,
+    [],
+    "Should remove all tombstones after resetting bookmarks sync ID"
+  );
+
+  info("Set bookmarks last sync time");
+  let lastSync = Date.now() / 1000;
+  await PlacesSyncUtils.bookmarks.setLastSync(lastSync);
+  equal(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    lastSync,
+    "Should record bookmarks last sync time"
+  );
+
+  newSyncId = await PlacesSyncUtils.bookmarks.resetSyncId();
+  notEqual(
+    newSyncId,
+    syncId,
+    "Should set new bookmarks sync ID if one already exists"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    0,
+    "Should reset bookmarks last sync time after resetting sync ID"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_wipe() {
+  info("Add Sync metadata before wipe");
+  let newSyncId = await PlacesSyncUtils.bookmarks.resetSyncId();
+  await PlacesSyncUtils.bookmarks.setLastSync(Date.now() / 1000);
+
+  let existingSyncId = await PlacesSyncUtils.bookmarks.getSyncId();
+  equal(
+    existingSyncId,
+    newSyncId,
+    "Ensure bookmarks sync ID was recorded before wipe"
+  );
+
+  info("Set up local tree before wipe");
+  await ignoreChangedRoots();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "bookmarkCCCC",
+    title: "C",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: "bookmarkDDDD",
+    title: "D",
+    url: "http://example.com/d",
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  info("Wipe bookmarks");
+  await PlacesSyncUtils.bookmarks.wipe();
+
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getSyncId(),
+    "",
+    "Should reset bookmarks sync ID after wipe"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    0,
+    "Should reset bookmarks last sync after wipe"
+  );
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Wiping bookmarks locally should not wipe server"
+  );
+
+  let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+  deepEqual(tombstones, [], "Should drop tombstones after wipe");
+
+  deepEqual(
+    await PlacesSyncUtils.bookmarks.fetchChildRecordIds("menu"),
+    [],
+    "Should wipe menu children"
+  );
+  deepEqual(
+    await PlacesSyncUtils.bookmarks.fetchChildRecordIds("toolbar"),
+    [],
+    "Should wipe toolbar children"
+  );
+
+  let rootSyncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.unfiledGuid
+  );
+  ok(
+    rootSyncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Should reset all sync statuses to NEW after wipe"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_meta_eraseEverything() {
+  info("Add Sync metadata before erase");
+  let newSyncId = await PlacesSyncUtils.bookmarks.resetSyncId();
+  let lastSync = Date.now() / 1000;
+  await PlacesSyncUtils.bookmarks.setLastSync(lastSync);
+
+  info("Set up local tree before reset");
+  await ignoreChangedRoots();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "bookmarkCCCC",
+    title: "C",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: "bookmarkDDDD",
+    title: "D",
+    url: "http://example.com/d",
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  info("Erase all bookmarks");
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getSyncId(),
+    newSyncId,
+    "Should not reset bookmarks sync ID after erase"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    lastSync,
+    "Should not reset bookmarks last sync after erase"
+  );
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Erasing everything should not wipe server"
+  );
+
+  deepEqual(
+    (await PlacesTestUtils.fetchSyncTombstones()).map(info => info.guid),
+    ["bookmarkAAAA", "bookmarkBBBB"],
+    "Should keep tombstones after erasing everything"
+  );
+
+  let rootSyncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    PlacesUtils.bookmarks.menuGuid,
+    PlacesUtils.bookmarks.toolbarGuid,
+    PlacesUtils.bookmarks.unfiledGuid,
+    PlacesUtils.bookmarks.mobileGuid
+  );
+  ok(
+    rootSyncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NORMAL
+    ),
+    "Should not reset sync statuses after erasing everything"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_reset() {
+  info("Add Sync metadata before reset");
+  await PlacesSyncUtils.bookmarks.resetSyncId();
+  await PlacesSyncUtils.bookmarks.setLastSync(Date.now() / 1000);
+
+  info("Set up local tree before reset");
+  await ignoreChangedRoots();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "bookmarkCCCC",
+    title: "C",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: "bookmarkDDDD",
+    title: "D",
+    url: "http://example.com/d",
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  info("Reset Sync metadata for bookmarks");
+  await PlacesSyncUtils.bookmarks.reset();
+
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getSyncId(),
+    "",
+    "Should reset bookmarks sync ID after reset"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    0,
+    "Should reset bookmarks last sync after reset"
+  );
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Resetting Sync metadata should not wipe server"
+  );
+
+  deepEqual(
+    await PlacesTestUtils.fetchSyncTombstones(),
+    [],
+    "Should drop tombstones after reset"
+  );
+
+  let itemSyncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    "bookmarkAAAA",
+    "bookmarkCCCC"
+  );
+  ok(
+    itemSyncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Should reset sync statuses for existing items to NEW after reset"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_meta_restore() {
+  info("Add Sync metadata before manual restore");
+  await PlacesSyncUtils.bookmarks.resetSyncId();
+  await PlacesSyncUtils.bookmarks.setLastSync(Date.now() / 1000);
+
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Should not wipe server before manual restore"
+  );
+
+  info("Manually restore");
+  let { path } = do_get_file("./sync_utils_bookmarks.json");
+  await BookmarkJSONUtils.importFromFile(path, { replace: true });
+
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getSyncId(),
+    "",
+    "Should reset bookmarks sync ID after manual restore"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    0,
+    "Should reset bookmarks last sync after manual restore"
+  );
+  ok(
+    await PlacesSyncUtils.bookmarks.shouldWipeRemote(),
+    "Should wipe server after manual restore"
+  );
+
+  let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    PlacesUtils.bookmarks.menuGuid,
+    "NnvGl3CRA4hC",
+    PlacesUtils.bookmarks.toolbarGuid,
+    "APzP8MupzA8l"
+  );
+  ok(
+    syncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.NEW
+    ),
+    "Should reset all sync stauses to NEW after manual restore"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_meta_restore_on_startup() {
+  info("Add Sync metadata before simulated automatic restore");
+  await PlacesSyncUtils.bookmarks.resetSyncId();
+  await PlacesSyncUtils.bookmarks.setLastSync(Date.now() / 1000);
+
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Should not wipe server before automatic restore"
+  );
+
+  info("Simulate automatic restore on startup");
+  let { path } = do_get_file("./sync_utils_bookmarks.json");
+  await BookmarkJSONUtils.importFromFile(path, {
+    replace: true,
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getSyncId(),
+    "",
+    "Should reset bookmarks sync ID after automatic restore"
+  );
+  strictEqual(
+    await PlacesSyncUtils.bookmarks.getLastSync(),
+    0,
+    "Should reset bookmarks last sync after automatic restore"
+  );
+  ok(
+    !(await PlacesSyncUtils.bookmarks.shouldWipeRemote()),
+    "Should not wipe server after manual restore"
+  );
+
+  let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+    PlacesUtils.bookmarks.menuGuid,
+    "NnvGl3CRA4hC",
+    PlacesUtils.bookmarks.toolbarGuid,
+    "APzP8MupzA8l"
+  );
+  ok(
+    syncFields.every(
+      field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN
+    ),
+    "Should reset all sync stauses to UNKNOWN after automatic restore"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_bookmarks_ensureCurrentSyncId() {
+  info("Set up local tree");
+  await ignoreChangedRoots();
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    source: PlacesUtils.bookmarks.SOURCES.SYNC,
+    children: [
+      {
+        guid: "bookmarkAAAA",
+        title: "A",
+        url: "http://example.com/a",
+      },
+      {
+        guid: "bookmarkBBBB",
+        title: "B",
+        url: "http://example.com/b",
+      },
+    ],
+  });
+  await PlacesUtils.bookmarks.remove("bookmarkBBBB");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    guid: "bookmarkCCCC",
+    title: "C",
+    url: "http://example.com/c",
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    guid: "bookmarkDDDD",
+    title: "D",
+    url: "http://example.com/d",
+    source: PlacesUtils.bookmarks.SOURCES.RESTORE_ON_STARTUP,
+  });
+
+  let existingSyncId = await PlacesSyncUtils.bookmarks.getSyncId();
+  strictEqual(existingSyncId, "", "Should start without bookmarks sync ID");
+
+  info("Assign new bookmarks sync ID");
+  {
+    await PlacesSyncUtils.bookmarks.ensureCurrentSyncId("syncIdAAAAAA");
+
+    let newSyncId = await PlacesSyncUtils.bookmarks.getSyncId();
+    equal(
+      newSyncId,
+      "syncIdAAAAAA",
+      "Should assign bookmarks sync ID if one doesn't exist"
+    );
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones.map(({ guid }) => guid),
+      ["bookmarkBBBB"],
+      "Should keep tombstones after assigning new bookmarks sync ID"
+    );
+
+    let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+      "bookmarkAAAA",
+      "bookmarkCCCC",
+      "bookmarkDDDD"
+    );
+    deepEqual(
+      syncFields.map(field => field.syncStatus),
+      [
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN,
+      ],
+      "Should not reset sync statuses after assigning new bookmarks sync ID"
+    );
+  }
+
+  info("Ensure existing bookmarks sync ID matches");
+  {
+    let lastSync = Date.now() / 1000;
+    await PlacesSyncUtils.bookmarks.setLastSync(lastSync);
+    await PlacesSyncUtils.bookmarks.ensureCurrentSyncId("syncIdAAAAAA");
+
+    equal(
+      await PlacesSyncUtils.bookmarks.getSyncId(),
+      "syncIdAAAAAA",
+      "Should keep existing bookmarks sync ID on match"
+    );
+    equal(
+      await PlacesSyncUtils.bookmarks.getLastSync(),
+      lastSync,
+      "Should keep existing bookmarks last sync time on sync ID match"
+    );
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones.map(({ guid }) => guid),
+      ["bookmarkBBBB"],
+      "Should keep tombstones if bookmarks sync IDs match"
+    );
+
+    let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+      "bookmarkAAAA",
+      "bookmarkCCCC",
+      "bookmarkDDDD"
+    );
+    deepEqual(
+      syncFields.map(field => field.syncStatus),
+      [
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NORMAL,
+        PlacesUtils.bookmarks.SYNC_STATUS.NEW,
+        PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN,
+      ],
+      "Should not reset sync statuses if bookmarks sync IDs match"
+    );
+  }
+
+  info("Replace existing bookmarks sync ID with new ID");
+  {
+    await PlacesSyncUtils.bookmarks.ensureCurrentSyncId("syncIdBBBBBB");
+
+    equal(
+      await PlacesSyncUtils.bookmarks.getSyncId(),
+      "syncIdBBBBBB",
+      "Should replace existing bookmarks sync ID on mismatch"
+    );
+    strictEqual(
+      await PlacesSyncUtils.bookmarks.getLastSync(),
+      0,
+      "Should reset bookmarks last sync time on sync ID mismatch"
+    );
+
+    let tombstones = await PlacesTestUtils.fetchSyncTombstones();
+    deepEqual(
+      tombstones,
+      [],
+      "Should drop tombstones after bookmarks sync ID mismatch"
+    );
+
+    let syncFields = await PlacesTestUtils.fetchBookmarkSyncFields(
+      PlacesUtils.bookmarks.menuGuid,
+      PlacesUtils.bookmarks.toolbarGuid,
+      PlacesUtils.bookmarks.unfiledGuid,
+      "bookmarkAAAA",
+      "bookmarkCCCC",
+      "bookmarkDDDD"
+    );
+    ok(
+      syncFields.every(
+        field => field.syncStatus == PlacesUtils.bookmarks.SYNC_STATUS.UNKNOWN
+      ),
+      "Should reset all sync statuses to UNKNOWN after bookmarks sync ID mismatch"
+    );
+  }
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesSyncUtils.bookmarks.reset();
+});
+
+add_task(async function test_history_resetSyncId() {
+  let syncId = await PlacesSyncUtils.history.getSyncId();
+  strictEqual(syncId, "", "Should start with empty history sync ID");
+
+  info("Assign new history sync ID for first time");
+  let newSyncId = await PlacesSyncUtils.history.resetSyncId();
+  syncId = await PlacesSyncUtils.history.getSyncId();
+  equal(newSyncId, syncId, "Should assign new history sync ID for first time");
+
+  info("Set history last sync time");
+  let lastSync = Date.now() / 1000;
+  await PlacesSyncUtils.history.setLastSync(lastSync);
+  equal(
+    await PlacesSyncUtils.history.getLastSync(),
+    lastSync,
+    "Should record history last sync time"
+  );
+
+  newSyncId = await PlacesSyncUtils.history.resetSyncId();
+  notEqual(
+    newSyncId,
+    syncId,
+    "Should set new history sync ID if one already exists"
+  );
+  strictEqual(
+    await PlacesSyncUtils.history.getLastSync(),
+    0,
+    "Should reset history last sync time after resetting sync ID"
+  );
+
+  await PlacesSyncUtils.history.reset();
+});
+
+add_task(async function test_history_ensureCurrentSyncId() {
+  info("Assign new history sync ID");
+  await PlacesSyncUtils.history.ensureCurrentSyncId("syncIdAAAAAA");
+  equal(
+    await PlacesSyncUtils.history.getSyncId(),
+    "syncIdAAAAAA",
+    "Should assign history sync ID if one doesn't exist"
+  );
+
+  info("Ensure existing history sync ID matches");
+  let lastSync = Date.now() / 1000;
+  await PlacesSyncUtils.history.setLastSync(lastSync);
+  await PlacesSyncUtils.history.ensureCurrentSyncId("syncIdAAAAAA");
+
+  equal(
+    await PlacesSyncUtils.history.getSyncId(),
+    "syncIdAAAAAA",
+    "Should keep existing history sync ID on match"
+  );
+  equal(
+    await PlacesSyncUtils.history.getLastSync(),
+    lastSync,
+    "Should keep existing history last sync time on sync ID match"
+  );
+
+  info("Replace existing history sync ID with new ID");
+  await PlacesSyncUtils.history.ensureCurrentSyncId("syncIdBBBBBB");
+
+  equal(
+    await PlacesSyncUtils.history.getSyncId(),
+    "syncIdBBBBBB",
+    "Should replace existing history sync ID on mismatch"
+  );
+  strictEqual(
+    await PlacesSyncUtils.history.getLastSync(),
+    0,
+    "Should reset history last sync time on sync ID mismatch"
+  );
+
+  await PlacesSyncUtils.history.reset();
+});
+
+add_task(async function test_updateUnknownFieldsBatch() {
+  // We're just validating we have something where placeId = 1, mainly as a sanity
+  // since moz_places_extra needs a valid foreign key
+  let placeId = await PlacesTestUtils.getDatabaseValue("moz_places", "id", {
+    id: 1,
+  });
+
+  // an example of json with multiple fields in it to test updateUnknownFields
+  // will update ONLY unknown_sync_fields and not override any others
+  const test_json = JSON.stringify({
+    unknown_sync_fields: { unknownStrField: "an old str field " },
+    extra_str_field: "another field within the json",
+    extra_obj_field: { inner: "hi" },
+  });
+
+  // Manually put the inital json in the DB
+  await PlacesUtils.withConnectionWrapper(
+    "test_update_moz_places_extra",
+    async function (db) {
+      await db.executeCached(
+        `
+        INSERT INTO moz_places_extra(place_id, sync_json)
+        VALUES(:placeId, :sync_json)`,
+        { placeId, sync_json: test_json }
+      );
+    }
+  );
+
+  // call updateUnknownFieldsBatch to validate it ONLY updates
+  // the unknown_sync_fields in the sync_json
+  let update = {
+    placeId,
+    unknownFields: JSON.stringify({ unknownStrField: "a new unknownStrField" }),
+  };
+  await PlacesSyncUtils.history.updateUnknownFieldsBatch([update]);
+
+  let updated_sync_json = await PlacesTestUtils.getDatabaseValue(
+    "moz_places_extra",
+    "sync_json",
+    {
+      place_id: placeId,
+    }
+  );
+
+  let updated_data = JSON.parse(updated_sync_json);
+
+  // unknown_sync_fields has been updated
+  deepEqual(JSON.parse(updated_data.unknown_sync_fields), {
+    unknownStrField: "a new unknownStrField",
+  });
+
+  // we didn't override any other fields within
+  deepEqual(updated_data.extra_str_field, "another field within the json");
+});
diff --git a/toolkit/components/places/tests/sync/xpcshell.toml b/toolkit/components/places/tests/sync/xpcshell.toml
new file mode 100644
index 0000000000..9d04b8aaad
--- /dev/null
+++ b/toolkit/components/places/tests/sync/xpcshell.toml
@@ -0,0 +1,40 @@
+[DEFAULT]
+head = "head_sync.js"
+support-files = [
+  "sync_utils_bookmarks.html",
+  "sync_utils_bookmarks.json",
+  "mirror_corrupt.sqlite",
+  "mirror_v1.sqlite",
+  "mirror_v5.sqlite",
+  "mirror_v8.sqlite",
+]
+
+["test_bookmark_abort_merging.js"]
+
+["test_bookmark_chunking.js"]
+
+["test_bookmark_corruption.js"]
+
+["test_bookmark_deduping.js"]
+
+["test_bookmark_deletion.js"]
+
+["test_bookmark_haschanges.js"]
+
+["test_bookmark_kinds.js"]
+
+["test_bookmark_mirror_meta.js"]
+
+["test_bookmark_mirror_migration.js"]
+
+["test_bookmark_observer_recorder.js"]
+
+["test_bookmark_reconcile.js"]
+
+["test_bookmark_structure_changes.js"]
+
+["test_bookmark_unknown_fields.js"]
+
+["test_bookmark_value_changes.js"]
+
+["test_sync_utils.js"]
diff --git a/toolkit/components/places/tests/unit/bookmarks.corrupt.html b/toolkit/components/places/tests/unit/bookmarks.corrupt.html
new file mode 100644
index 0000000000..3cf43367fb
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks.corrupt.html
@@ -0,0 +1,36 @@
+<!DOCTYPE NETSCAPE-Bookmark-file-1>
+<!-- This is an automatically generated file.
+     It will be read and overwritten.
+     DO NOT EDIT! -->
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+<TITLE>Bookmarks</TITLE>
+<H1 LAST_MODIFIED="1177541029">Bookmarks</H1>
+
+<DL><p>
+    <DT><H3 ID="rdf:#$ZvPhC3">Mozilla Firefox</H3>
+    <DL><p>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/help/" ICON="data:image/png;base64,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" ID="rdf:#$22iCK1">Help and Tutorials</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/customize/" ICON="data:image/png;base64,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" ID="rdf:#$32iCK1">Customize Firefox</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/community/" ICON="data:image/png;base64,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" ID="rdf:#$42iCK1">Get Involved</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/about/" ICON="data:image/png;base64,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" ID="rdf:#$52iCK1">About Us</A>
+        <DT><A HREF="b0rked" ICON="data:image/png;base64,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" ID="rdf:#$52iCK1">About Us</A>
+    </DL><p>
+    <DT><H3 ADD_DATE="1177541020" LAST_MODIFIED="1177541050" ID="rdf:#$74Gpx2">test</H3>
+<DD>folder test comment
+    <DL><p>
+        <DT><A HREF="http://test/post" ADD_DATE="1177375336" LAST_MODIFIED="1177375423" SHORTCUTURL="test" WEB_PANEL="true" POST_DATA="hidden1%3Dbar&amp;text1%3D%25s" LAST_CHARSET="ISO-8859-1" ID="rdf:#$pYFe7">test post keyword</A>
+<DD>item description
+    </DL>
+    <DT><H3 UNFILED_BOOKMARKS_FOLDER="true">Unsorted Bookmarks</H3>
+    <DL><p>
+        <DT><A HREF="http://example.tld">Example.tld</A>
+    </DL><p>
+    <DT><H3 LAST_MODIFIED="1177541040" PERSONAL_TOOLBAR_FOLDER="true" ID="rdf:#$FvPhC3">Bookmarks Toolbar Folder</H3>
+<DD>Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar
+    <DL><p>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/central/" ICON="data:image/png;base64,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" ID="rdf:#$GvPhC3">Getting Started</A>
+        <DT><A HREF="http://en-US.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/" LAST_MODIFIED="1177541035" FEEDURL="http://en-US.fxfeeds.mozilla.com/en-US/firefox/headlines.xml" ID="rdf:#$HvPhC3">Latest Headlines</A>
+        <DT><A HREF="http://bogus-icon.mozilla.com/" ICON="b0rked" ID="rdf:#$GvPhC3">Getting Started</A>
+<DD>Livemark test comment
+    </DL><p>
+</DL><p>
diff --git a/toolkit/components/places/tests/unit/bookmarks.json b/toolkit/components/places/tests/unit/bookmarks.json
new file mode 100644
index 0000000000..27ed9ce5ca
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks.json
@@ -0,0 +1,307 @@
+{
+  "guid": "root________",
+  "title": "",
+  "id": 1,
+  "dateAdded": 1361551978957783,
+  "lastModified": 1361551978957783,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "id": 2,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551979382837,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FF",
+          "title": "Mozilla Firefox",
+          "id": 6,
+          "parent": 2,
+          "dateAdded": 1361551979350273,
+          "lastModified": 1361551979376699,
+          "type": "text/x-moz-place-container",
+          "children": [
+            {
+              "guid": "OCyeUO5uu9FG",
+              "title": "Help and Tutorials",
+              "id": 7,
+              "parent": 6,
+              "dateAdded": 1361551979356436,
+              "lastModified": 1361551979362718,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/help/",
+              "icon": "data:image/png;base64,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"
+            },
+            {
+              "guid": "OCyeUO5uu9FH",
+              "index": 1,
+              "title": "Customize Firefox",
+              "id": 8,
+              "parent": 6,
+              "dateAdded": 1361551979365662,
+              "lastModified": 1361551979368077,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/customize/",
+              "icon": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg=="
+            },
+            {
+              "guid": "OCyeUO5uu9FJ",
+              "index": 3,
+              "title": "About Us",
+              "id": 10,
+              "parent": 6,
+              "dateAdded": 1361551979376699,
+              "lastModified": 1361551979379060,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/about/",
+              "icon": "data:image/png;base64,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"
+            },
+            {
+              "guid": "OCyeUO5uu9FI",
+              "index": 2,
+              "title": "Get Involved",
+              "id": 9,
+              "parent": 6,
+              "dateAdded": 1361551979371071,
+              "lastModified": 1361551979373745,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/community/",
+              "icon": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg=="
+            },
+            {
+              "guid": "QFM-QnE2ZpMz",
+              "title": "Test null postData",
+              "index": 4,
+              "dateAdded": 1481639510868000,
+              "lastModified": 1489563704300000,
+              "id": 17,
+              "charset": "UTF-8",
+              "annos": [
+                {
+                  "name": "bookmarkProperties/description",
+                  "flags": 0,
+                  "expires": 4,
+                  "value": "The best"
+                }
+              ],
+              "type": "text/x-moz-place",
+              "uri": "http://example.com/search?q=%s&suggid=",
+              "postData": null
+            }
+          ]
+        },
+        {
+          "guid": "OCyeUO5uu9FK",
+          "index": 1,
+          "title": "",
+          "id": 11,
+          "parent": 2,
+          "dateAdded": 1361551979380988,
+          "lastModified": 1361551979380988,
+          "type": "text/x-moz-place-separator"
+        },
+        {
+          "guid": "OCyeUO5uu9FL",
+          "index": 2,
+          "title": "test",
+          "id": 12,
+          "parent": 2,
+          "dateAdded": 1177541020000000,
+          "lastModified": 1177541050000000,
+          "annos": [
+            {
+              "name": "bookmarkProperties/description",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "folder test comment"
+            }
+          ],
+          "type": "text/x-moz-place-container",
+          "children": [
+            {
+              "guid": "OCyeUO5uu9GX",
+              "title": "test post keyword",
+              "id": 13,
+              "parent": 12,
+              "dateAdded": 1177375336000000,
+              "lastModified": 1177375423000000,
+              "annos": [
+                {
+                  "name": "bookmarkProperties/description",
+                  "flags": 0,
+                  "expires": 4,
+                  "mimeType": null,
+                  "type": 3,
+                  "value": "item description"
+                },
+                {
+                  "name": "bookmarkProperties/loadInSidebar",
+                  "flags": 0,
+                  "expires": 4,
+                  "mimeType": null,
+                  "type": 1,
+                  "value": 1
+                }
+              ],
+              "type": "text/x-moz-place",
+              "uri": "http://test/post",
+              "keyword": "test",
+              "charset": "ISO-8859-1",
+              "postData": "hidden1%3Dbar&text1%3D%25s"
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "index": 1,
+      "title": "Bookmarks Toolbar",
+      "id": 3,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1177541050000000,
+      "annos": [
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "mimeType": null,
+          "type": 3,
+          "value": "Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FB",
+          "title": "Getting Started",
+          "id": 15,
+          "parent": 3,
+          "dateAdded": 1361551979409695,
+          "lastModified": 1361551979412080,
+          "type": "text/x-moz-place",
+          "uri": "http://en-us.www.mozilla.com/en-US/firefox/central/",
+          "icon": "data:image/png;base64,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"
+        },
+        {
+          "guid": "OCyeUO5uu9FR",
+          "index": 1,
+          "title": "Latest Headlines",
+          "id": 16,
+          "parent": 3,
+          "dateAdded": 1361551979451584,
+          "lastModified": 1361551979457086,
+          "livemark": 1,
+          "annos": [
+            {
+              "name": "livemark/feedURI",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "http://en-us.fxfeeds.mozilla.com/en-US/firefox/headlines.xml"
+            },
+            {
+              "name": "livemark/siteURI",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "http://en-us.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/"
+            }
+          ],
+          "type": "text/x-moz-place-container",
+          "children": []
+        }
+      ]
+    },
+    {
+      "index": 2,
+      "title": "Tags",
+      "id": 4,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551978957783,
+      "type": "text/x-moz-place-container",
+      "root": "tagsFolder",
+      "children": []
+    },
+    {
+      "index": 3,
+      "title": "Unsorted Bookmarks",
+      "id": 5,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1177541050000000,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FW",
+          "title": "Example.tld",
+          "id": 14,
+          "parent": 5,
+          "dateAdded": 1361551979401846,
+          "lastModified": 1361551979402952,
+          "type": "text/x-moz-place",
+          "uri": "http://example.tld/"
+        },
+        {
+          "guid": "Cfkety492Afk",
+          "title": "test tagged bookmark",
+          "id": 15,
+          "parent": 5,
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "type": "text/x-moz-place",
+          "uri": "http://example.tld/tagged",
+          "tags": "foo"
+        },
+        {
+          "guid": "lOZGoFR1eXbl",
+          "title": "Bookmarks Toolbar Shortcut",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 16,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=TOOLBAR"
+        },
+        {
+          "guid": "7yJWnBVhjRtP",
+          "title": "Folder Shortcut",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 17,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6"
+        },
+        {
+          "guid": "vm5QXWuWc12l",
+          "title": "Folder Shortcut 2",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 18,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6123443"
+        },
+        {
+          "guid": "Icg1XlIozA1D",
+          "title": "Folder Shortcut 3",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 18,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6&folder=BOOKMARKS_MENU"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/bookmarks.preplaces.html b/toolkit/components/places/tests/unit/bookmarks.preplaces.html
new file mode 100644
index 0000000000..0ddf7725b4
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks.preplaces.html
@@ -0,0 +1,36 @@
+<!DOCTYPE NETSCAPE-Bookmark-file-1>
+<!-- This is an automatically generated file.
+     It will be read and overwritten.
+     DO NOT EDIT! -->
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+<TITLE>Bookmarks</TITLE>
+<H1 LAST_MODIFIED="1177541029">Bookmarks</H1>
+
+<DL><p>
+    <DT><H3 ID="rdf:#$ZvPhC3">Mozilla Firefox</H3>
+    <DL><p>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/help/" ICON="data:image/png;base64,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" ID="rdf:#$22iCK1">Help and Tutorials</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/customize/" ICON="data:image/png;base64,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" ID="rdf:#$32iCK1">Customize Firefox</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/community/" ICON="data:image/png;base64,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" ID="rdf:#$42iCK1">Get Involved</A>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/about/" ICON="data:image/png;base64,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" ID="rdf:#$52iCK1">About Us</A>
+    </DL><p>
+    <HR>
+    <DT><H3 ADD_DATE="1177541020" LAST_MODIFIED="1177541050" ID="rdf:#$74Gpx2">test</H3>
+<DD>folder test comment
+    <DL><p>
+        <DT><A HREF="http://test/post" ADD_DATE="1177375336" LAST_MODIFIED="1177375423" SHORTCUTURL="test" WEB_PANEL="true" POST_DATA="hidden1%3Dbar&amp;text1%3D%25s" LAST_CHARSET="ISO-8859-1" ID="rdf:#$pYFe7">test post keyword</A>
+<DD>item description
+    </DL>
+    <DT><H3 UNFILED_BOOKMARKS_FOLDER="true">Unsorted Bookmarks</H3>
+    <DL><p>
+        <DT><A HREF="http://example.tld">Example.tld</A>
+    </DL><p>
+    <DT><H3 LAST_MODIFIED="1177541040" PERSONAL_TOOLBAR_FOLDER="true" ID="rdf:#$FvPhC3">Bookmarks Toolbar Folder</H3>
+<DD>Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar
+    <DL><p>
+        <DT><A HREF="http://en-US.www.mozilla.com/en-US/firefox/central/" ICON="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg==" ID="rdf:#$GvPhC3">Getting Started</A>
+        <DT><A HREF="http://en-US.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/" LAST_MODIFIED="1177541035" FEEDURL="http://en-US.fxfeeds.mozilla.com/en-US/firefox/headlines.xml" ID="rdf:#$HvPhC3">Latest Headlines</A>
+        <DT><A LAST_MODIFIED="1177541035" FEEDURL="http://en-US.fxfeeds.mozilla.com/en-US/firefox/headlines.xml" ID="rdf:#$HvPhC3">Latest Headlines No Site</A>
+<DD>Livemark test comment
+    </DL><p>
+</DL><p>
diff --git a/toolkit/components/places/tests/unit/bookmarks_corrupt.json b/toolkit/components/places/tests/unit/bookmarks_corrupt.json
new file mode 100644
index 0000000000..93f21d3ece
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks_corrupt.json
@@ -0,0 +1,72 @@
+{
+  "guid": "root________",
+  "title": "",
+  "id": 1,
+  "dateAdded": 1361551978957783,
+  "lastModified": 1361551978957783,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "id": 2,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551979382837,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FG",
+          "title": "Help and Tutorials",
+          "id": 7,
+          "dateAdded": 1361551979356436,
+          "lastModified": 1361551979362718,
+          "type": "x/invalid",
+          "uri": "http://en-us.www.mozilla.com/en-US/firefox/help/"
+        },
+        {
+          "guid": "OCyeUO5uu9FH",
+          "index": 1,
+          "title": "Customize Firefox",
+          "id": 8,
+          "dateAdded": 1361551979365662,
+          "lastModified": 1361551979368077,
+          "type": "text/x-moz-place",
+          "uri": "http://en-us.www.mozilla.com/en-US/firefox/customize/"
+        },
+        {
+          "guid": "OCyeUO5uu9FG",
+          "title": "Bad URL",
+          "id": 9,
+          "dateAdded": 1361551979356436,
+          "lastModified": 1361551979362718,
+          "type": "text/x-moz-place",
+          "uri": "http:///"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "id": 2,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551979382837,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FG",
+          "title": "Bad URL",
+          "id": 9,
+          "dateAdded": 1361551979356436,
+          "lastModified": 1361551979362718,
+          "type": "text/x-moz-place",
+          "uri": "http:///"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/bookmarks_html_localized.html b/toolkit/components/places/tests/unit/bookmarks_html_localized.html
new file mode 100644
index 0000000000..bc3bacc54d
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks_html_localized.html
@@ -0,0 +1,21 @@
+<!DOCTYPE NETSCAPE-Bookmark-file-1>
+<!-- This is an automatically generated file.
+     It will be read and overwritten.
+     DO NOT EDIT! -->
+<HTML>
+<HEAD>
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+<TITLE>Bookmarks</TITLE>
+<LINK REL="localization" HREF="bookmarks_html_localized.ftl">
+</HEAD>
+<BODY>
+<H1 LAST_MODIFIED="1177541029">Bookmarks</H1>
+
+<DL><p>
+    <DT><H3 ID="rdf:#$ZvPhC3" data-l10n-id="bookmarks-html-localized-folder">bookmarks-html-localized-folder</H3>
+    <DL><p>
+        <DT><A HREF="http://www.mozilla.com/firefox/help/" ICON="data:image/png;base64,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" ID="rdf:#$22iCK1" data-l10n-id="bookmarks-html-localized-bookmark">bookmarks-html-localized-bookmark</A>
+    </DL><p>
+</DL><p>
+</BODY>
+</HTML>
diff --git a/toolkit/components/places/tests/unit/bookmarks_html_singleframe.html b/toolkit/components/places/tests/unit/bookmarks_html_singleframe.html
new file mode 100644
index 0000000000..9fe662f320
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks_html_singleframe.html
@@ -0,0 +1,10 @@
+<!DOCTYPE NETSCAPE-Bookmark-file-1>
+	<HTML>
+	<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+	<Title>Bookmarks</Title>
+	<H1>Bookmarks</H1>
+    <DT><H3>Subtitle</H3>
+	<DL><p>
+		<DT><A HREF="http://www.mozilla.org/">Mozilla</A>
+    </DL><p>
+</HTML>
diff --git a/toolkit/components/places/tests/unit/bookmarks_iconuri.json b/toolkit/components/places/tests/unit/bookmarks_iconuri.json
new file mode 100644
index 0000000000..4059c1d53f
--- /dev/null
+++ b/toolkit/components/places/tests/unit/bookmarks_iconuri.json
@@ -0,0 +1,307 @@
+{
+  "guid": "root________",
+  "title": "",
+  "id": 1,
+  "dateAdded": 1361551978957783,
+  "lastModified": 1361551978957783,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "id": 2,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551979382837,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FF",
+          "title": "Mozilla Firefox",
+          "id": 6,
+          "parent": 2,
+          "dateAdded": 1361551979350273,
+          "lastModified": 1361551979376699,
+          "type": "text/x-moz-place-container",
+          "children": [
+            {
+              "guid": "OCyeUO5uu9FG",
+              "title": "Help and Tutorials",
+              "id": 7,
+              "parent": 6,
+              "dateAdded": 1361551979356436,
+              "lastModified": 1361551979362718,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/help/",
+              "iconUri": "data:image/png;base64,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"
+            },
+            {
+              "guid": "OCyeUO5uu9FH",
+              "index": 1,
+              "title": "Customize Firefox",
+              "id": 8,
+              "parent": 6,
+              "dateAdded": 1361551979365662,
+              "lastModified": 1361551979368077,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/customize/",
+              "iconUri": "data:image/png;base64,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"
+            },
+            {
+              "guid": "OCyeUO5uu9FJ",
+              "index": 3,
+              "title": "About Us",
+              "id": 10,
+              "parent": 6,
+              "dateAdded": 1361551979376699,
+              "lastModified": 1361551979379060,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/about/",
+              "iconUri": "data:image/png;base64,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"
+            },
+            {
+              "guid": "OCyeUO5uu9FI",
+              "index": 2,
+              "title": "Get Involved",
+              "id": 9,
+              "parent": 6,
+              "dateAdded": 1361551979371071,
+              "lastModified": 1361551979373745,
+              "type": "text/x-moz-place",
+              "uri": "http://en-us.www.mozilla.com/en-US/firefox/community/",
+              "iconUri": "data:image/png;base64,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"
+            },
+            {
+              "guid": "QFM-QnE2ZpMz",
+              "title": "Test null postData",
+              "index": 4,
+              "dateAdded": 1481639510868000,
+              "lastModified": 1489563704300000,
+              "id": 17,
+              "charset": "UTF-8",
+              "annos": [
+                {
+                  "name": "bookmarkProperties/description",
+                  "flags": 0,
+                  "expires": 4,
+                  "value": "The best"
+                }
+              ],
+              "type": "text/x-moz-place",
+              "uri": "http://example.com/search?q=%s&suggid=",
+              "postData": null
+            }
+          ]
+        },
+        {
+          "guid": "OCyeUO5uu9FK",
+          "index": 1,
+          "title": "",
+          "id": 11,
+          "parent": 2,
+          "dateAdded": 1361551979380988,
+          "lastModified": 1361551979380988,
+          "type": "text/x-moz-place-separator"
+        },
+        {
+          "guid": "OCyeUO5uu9FL",
+          "index": 2,
+          "title": "test",
+          "id": 12,
+          "parent": 2,
+          "dateAdded": 1177541020000000,
+          "lastModified": 1177541050000000,
+          "annos": [
+            {
+              "name": "bookmarkProperties/description",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "folder test comment"
+            }
+          ],
+          "type": "text/x-moz-place-container",
+          "children": [
+            {
+              "guid": "OCyeUO5uu9GX",
+              "title": "test post keyword",
+              "id": 13,
+              "parent": 12,
+              "dateAdded": 1177375336000000,
+              "lastModified": 1177375423000000,
+              "annos": [
+                {
+                  "name": "bookmarkProperties/description",
+                  "flags": 0,
+                  "expires": 4,
+                  "mimeType": null,
+                  "type": 3,
+                  "value": "item description"
+                },
+                {
+                  "name": "bookmarkProperties/loadInSidebar",
+                  "flags": 0,
+                  "expires": 4,
+                  "mimeType": null,
+                  "type": 1,
+                  "value": 1
+                }
+              ],
+              "type": "text/x-moz-place",
+              "uri": "http://test/post",
+              "keyword": "test",
+              "charset": "ISO-8859-1",
+              "postData": "hidden1%3Dbar&text1%3D%25s"
+            }
+          ]
+        }
+      ]
+    },
+    {
+      "index": 1,
+      "title": "Bookmarks Toolbar",
+      "id": 3,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1177541050000000,
+      "annos": [
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "mimeType": null,
+          "type": 3,
+          "value": "Add bookmarks to this folder to see them displayed on the Bookmarks Toolbar"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FB",
+          "title": "Getting Started",
+          "id": 15,
+          "parent": 3,
+          "dateAdded": 1361551979409695,
+          "lastModified": 1361551979412080,
+          "type": "text/x-moz-place",
+          "uri": "http://en-us.www.mozilla.com/en-US/firefox/central/",
+          "iconUri": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg=="
+        },
+        {
+          "guid": "OCyeUO5uu9FR",
+          "index": 1,
+          "title": "Latest Headlines",
+          "id": 16,
+          "parent": 3,
+          "dateAdded": 1361551979451584,
+          "lastModified": 1361551979457086,
+          "livemark": 1,
+          "annos": [
+            {
+              "name": "livemark/feedURI",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "http://en-us.fxfeeds.mozilla.com/en-US/firefox/headlines.xml"
+            },
+            {
+              "name": "livemark/siteURI",
+              "flags": 0,
+              "expires": 4,
+              "mimeType": null,
+              "type": 3,
+              "value": "http://en-us.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/"
+            }
+          ],
+          "type": "text/x-moz-place-container",
+          "children": []
+        }
+      ]
+    },
+    {
+      "index": 2,
+      "title": "Tags",
+      "id": 4,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1361551978957783,
+      "type": "text/x-moz-place-container",
+      "root": "tagsFolder",
+      "children": []
+    },
+    {
+      "index": 3,
+      "title": "Unsorted Bookmarks",
+      "id": 5,
+      "parent": 1,
+      "dateAdded": 1361551978957783,
+      "lastModified": 1177541050000000,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder",
+      "children": [
+        {
+          "guid": "OCyeUO5uu9FW",
+          "title": "Example.tld",
+          "id": 14,
+          "parent": 5,
+          "dateAdded": 1361551979401846,
+          "lastModified": 1361551979402952,
+          "type": "text/x-moz-place",
+          "uri": "http://example.tld/"
+        },
+        {
+          "guid": "Cfkety492Afk",
+          "title": "test tagged bookmark",
+          "id": 15,
+          "parent": 5,
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "type": "text/x-moz-place",
+          "uri": "http://example.tld/tagged",
+          "tags": "foo"
+        },
+        {
+          "guid": "lOZGoFR1eXbl",
+          "title": "Bookmarks Toolbar Shortcut",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 16,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=TOOLBAR"
+        },
+        {
+          "guid": "7yJWnBVhjRtP",
+          "title": "Folder Shortcut",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 17,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6"
+        },
+        {
+          "guid": "vm5QXWuWc12l",
+          "title": "Folder Shortcut 2",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 18,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6123443"
+        },
+        {
+          "guid": "Icg1XlIozA1D",
+          "title": "Folder Shortcut 3",
+          "dateAdded": 1507025843703345,
+          "lastModified": 1507025844703124,
+          "id": 18,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=6&folder=BOOKMARKS_MENU"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/head_bookmarks.js b/toolkit/components/places/tests/unit/head_bookmarks.js
new file mode 100644
index 0000000000..5f6250aa5d
--- /dev/null
+++ b/toolkit/components/places/tests/unit/head_bookmarks.js
@@ -0,0 +1,30 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Import common head.
+{
+  /* import-globals-from ../head_common.js */
+  let commonFile = do_get_file("../head_common.js", false);
+  let uri = Services.io.newFileURI(commonFile);
+  Services.scriptloader.loadSubScript(uri.spec, this);
+}
+
+// Put any other stuff relative to this test folder below.
+const { AddonTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/AddonTestUtils.sys.mjs"
+);
+
+AddonTestUtils.init(this, false);
+AddonTestUtils.overrideCertDB();
+AddonTestUtils.createAppInfo(
+  "xpcshell@tests.mozilla.org",
+  "XPCShell",
+  "1",
+  "42"
+);
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+});
diff --git a/toolkit/components/places/tests/unit/mobile_bookmarks_folder_import.json b/toolkit/components/places/tests/unit/mobile_bookmarks_folder_import.json
new file mode 100644
index 0000000000..930b7a8382
--- /dev/null
+++ b/toolkit/components/places/tests/unit/mobile_bookmarks_folder_import.json
@@ -0,0 +1,135 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1475084731479000,
+  "lastModified": 1475084731479000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731768000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "X6lUyOspVYwi",
+          "title": "Test Pilot",
+          "index": 0,
+          "dateAdded": 1475084731768000,
+          "lastModified": 1475084731768000,
+          "id": 3,
+          "type": "text/x-moz-place",
+          "uri": "https://testpilot.firefox.com/"
+        },
+        {
+          "guid": "XF4yRP6bTuil",
+          "title": "Mobile bookmarks query",
+          "index": 1,
+          "dateAdded": 1475084731768000,
+          "lastModified": 1475084731768000,
+          "id": 11,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=101"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 4,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "buy7711R3ZgE",
+          "title": "MDN",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 5,
+          "type": "text/x-moz-place",
+          "uri": "https://developer.mozilla.org"
+        }
+      ]
+    },
+    {
+      "guid": "3qmd_imziEBE",
+      "title": "Mobile Bookmarks",
+      "index": 5,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731770000,
+      "id": 101,
+      "annos": [
+        {
+          "name": "mobile/bookmarksRoot",
+          "flags": 0,
+          "expires": 4,
+          "value": 1
+        },
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "mimeType": null,
+          "type": 3,
+          "value": "A description of the mobile folder that should be ignored on import"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "children": [
+        {
+          "guid": "_o8e1_zxTJFg",
+          "title": "Get Firefox!",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 7,
+          "type": "text/x-moz-place",
+          "uri": "http://getfirefox.com/"
+        },
+        {
+          "guid": "QCtSqkVYUbXB",
+          "title": "Get Thunderbird!",
+          "index": 1,
+          "dateAdded": 1475084731770000,
+          "lastModified": 1475084731770000,
+          "id": 8,
+          "type": "text/x-moz-place",
+          "uri": "http://getthunderbird.com/"
+        }
+      ]
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 9,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder",
+      "children": [
+        {
+          "guid": "KIa9iKZab2Z5",
+          "title": "Add-ons",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 10,
+          "type": "text/x-moz-place",
+          "uri": "https://addons.mozilla.org"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/mobile_bookmarks_folder_merge.json b/toolkit/components/places/tests/unit/mobile_bookmarks_folder_merge.json
new file mode 100644
index 0000000000..8d376bf69c
--- /dev/null
+++ b/toolkit/components/places/tests/unit/mobile_bookmarks_folder_merge.json
@@ -0,0 +1,101 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1475084731479000,
+  "lastModified": 1475084731479000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731768000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "Utodo9b0oVws",
+          "title": "Firefox Accounts",
+          "index": 0,
+          "dateAdded": 1475084731955000,
+          "lastModified": 1475084731955000,
+          "id": 3,
+          "type": "text/x-moz-place",
+          "uri": "https://accounts.firefox.com/"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 4,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder"
+    },
+    {
+      "guid": "3qmd_imziEBE",
+      "title": "Mobile Bookmarks",
+      "index": 5,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731770000,
+      "id": 5,
+      "annos": [
+        {
+          "name": "mobile/bookmarksRoot",
+          "flags": 0,
+          "expires": 4,
+          "value": 1
+        },
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "mimeType": null,
+          "type": 3,
+          "value": "A description of the mobile folder that should be ignored on import"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "children": [
+        {
+          "guid": "a17yW6-nTxEJ",
+          "title": "Mozilla",
+          "index": 0,
+          "dateAdded": 1475084731959000,
+          "lastModified": 1475084731959000,
+          "id": 6,
+          "type": "text/x-moz-place",
+          "uri": "https://mozilla.org/"
+        },
+        {
+          "guid": "xV10h9Wi3FBM",
+          "title": "Bugzilla",
+          "index": 1,
+          "dateAdded": 1475084731961000,
+          "lastModified": 1475084731961000,
+          "id": 7,
+          "type": "text/x-moz-place",
+          "uri": "https://bugzilla.mozilla.org/"
+        }
+      ]
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 8,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder"
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/mobile_bookmarks_multiple_folders.json b/toolkit/components/places/tests/unit/mobile_bookmarks_multiple_folders.json
new file mode 100644
index 0000000000..3c5cb63194
--- /dev/null
+++ b/toolkit/components/places/tests/unit/mobile_bookmarks_multiple_folders.json
@@ -0,0 +1,159 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1475084731479000,
+  "lastModified": 1475084731479000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731768000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "buy7711R3ZgE",
+          "title": "MDN",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 3,
+          "type": "text/x-moz-place",
+          "uri": "https://developer.mozilla.org"
+        },
+        {
+          "guid": "F_LBgd1fS_uQ",
+          "title": "Mobile bookmarks query for first folder",
+          "index": 1,
+          "dateAdded": 1475084731768000,
+          "lastModified": 1475084731768000,
+          "id": 11,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=101"
+        },
+        {
+          "guid": "oIpmQXMWsXvY",
+          "title": "Mobile bookmarks query for second folder",
+          "index": 2,
+          "dateAdded": 1475084731768000,
+          "lastModified": 1475084731768000,
+          "id": 12,
+          "type": "text/x-moz-place",
+          "uri": "place:folder=102"
+        }
+      ]
+    },
+    {
+      "guid": "3qmd_imziEBE",
+      "title": "Mobile Bookmarks",
+      "index": 5,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731770000,
+      "id": 101,
+      "annos": [
+        {
+          "name": "mobile/bookmarksRoot",
+          "flags": 0,
+          "expires": 4,
+          "value": 1
+        },
+        {
+          "name": "bookmarkProperties/description",
+          "flags": 0,
+          "expires": 4,
+          "mimeType": null,
+          "type": 3,
+          "value": "A description of the mobile folder that should be ignored on import"
+        }
+      ],
+      "type": "text/x-moz-place-container",
+      "children": [
+        {
+          "guid": "a17yW6-nTxEJ",
+          "title": "Mozilla",
+          "index": 0,
+          "dateAdded": 1475084731959000,
+          "lastModified": 1475084731959000,
+          "id": 5,
+          "type": "text/x-moz-place",
+          "uri": "https://mozilla.org/"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 6,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder",
+      "children": [
+        {
+          "guid": "Utodo9b0oVws",
+          "title": "Firefox Accounts",
+          "index": 0,
+          "dateAdded": 1475084731955000,
+          "lastModified": 1475084731955000,
+          "id": 7,
+          "type": "text/x-moz-place",
+          "uri": "https://accounts.firefox.com/"
+        }
+      ]
+    },
+    {
+      "guid": "o4YjJpgsufU-",
+      "title": "Mobile Bookmarks",
+      "index": 7,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731770000,
+      "id": 102,
+      "annos": [
+        { "name": "mobile/bookmarksRoot", "flags": 0, "expires": 4, "value": 1 }
+      ],
+      "type": "text/x-moz-place-container",
+      "children": [
+        {
+          "guid": "sSZ86WT9WbN3",
+          "title": "DXR",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 9,
+          "type": "text/x-moz-place",
+          "uri": "https://dxr.mozilla.org"
+        }
+      ]
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 10,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder",
+      "children": [
+        {
+          "guid": "xV10h9Wi3FBM",
+          "title": "Bugzilla",
+          "index": 1,
+          "dateAdded": 1475084731961000,
+          "lastModified": 1475084731961000,
+          "id": 11,
+          "type": "text/x-moz-place",
+          "uri": "https://bugzilla.mozilla.org/"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/mobile_bookmarks_root_import.json b/toolkit/components/places/tests/unit/mobile_bookmarks_root_import.json
new file mode 100644
index 0000000000..33908e1fea
--- /dev/null
+++ b/toolkit/components/places/tests/unit/mobile_bookmarks_root_import.json
@@ -0,0 +1,89 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1475084731479000,
+  "lastModified": 1475084731479000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731768000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "X6lUyOspVYwi",
+          "title": "Test Pilot",
+          "index": 0,
+          "dateAdded": 1475084731768000,
+          "lastModified": 1475084731768000,
+          "id": 3,
+          "type": "text/x-moz-place",
+          "uri": "https://testpilot.firefox.com/"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 4,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder"
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731742000,
+      "id": 5,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder"
+    },
+    {
+      "guid": "mobile______",
+      "title": "Mobile Bookmarks",
+      "index": 4,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731770000,
+      "id": 6,
+      "annos": [
+        { "name": "mobile/bookmarksRoot", "flags": 0, "expires": 4, "value": 1 }
+      ],
+      "type": "text/x-moz-place-container",
+      "root": "mobileFolder",
+      "children": [
+        {
+          "guid": "_o8e1_zxTJFg",
+          "title": "Get Firefox!",
+          "index": 0,
+          "dateAdded": 1475084731769000,
+          "lastModified": 1475084731769000,
+          "id": 7,
+          "type": "text/x-moz-place",
+          "uri": "http://getfirefox.com/"
+        },
+        {
+          "guid": "QCtSqkVYUbXB",
+          "title": "Get Thunderbird!",
+          "index": 1,
+          "dateAdded": 1475084731770000,
+          "lastModified": 1475084731770000,
+          "id": 8,
+          "type": "text/x-moz-place",
+          "uri": "http://getthunderbird.com/"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/mobile_bookmarks_root_merge.json b/toolkit/components/places/tests/unit/mobile_bookmarks_root_merge.json
new file mode 100644
index 0000000000..97af52c44a
--- /dev/null
+++ b/toolkit/components/places/tests/unit/mobile_bookmarks_root_merge.json
@@ -0,0 +1,89 @@
+{
+  "guid": "root________",
+  "title": "",
+  "index": 0,
+  "dateAdded": 1475084731479000,
+  "lastModified": 1475084731479000,
+  "id": 1,
+  "type": "text/x-moz-place-container",
+  "root": "placesRoot",
+  "children": [
+    {
+      "guid": "menu________",
+      "title": "Bookmarks Menu",
+      "index": 0,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731955000,
+      "id": 2,
+      "type": "text/x-moz-place-container",
+      "root": "bookmarksMenuFolder",
+      "children": [
+        {
+          "guid": "Utodo9b0oVws",
+          "title": "Firefox Accounts",
+          "index": 0,
+          "dateAdded": 1475084731955000,
+          "lastModified": 1475084731955000,
+          "id": 3,
+          "type": "text/x-moz-place",
+          "uri": "https://accounts.firefox.com/"
+        }
+      ]
+    },
+    {
+      "guid": "toolbar_____",
+      "title": "Bookmarks Toolbar",
+      "index": 1,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731938000,
+      "id": 4,
+      "type": "text/x-moz-place-container",
+      "root": "toolbarFolder"
+    },
+    {
+      "guid": "unfiled_____",
+      "title": "Other Bookmarks",
+      "index": 3,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731938000,
+      "id": 5,
+      "type": "text/x-moz-place-container",
+      "root": "unfiledBookmarksFolder"
+    },
+    {
+      "guid": "mobile______",
+      "title": "Mobile Bookmarks",
+      "index": 4,
+      "dateAdded": 1475084731479000,
+      "lastModified": 1475084731961000,
+      "id": 6,
+      "annos": [
+        { "name": "mobile/bookmarksRoot", "flags": 0, "expires": 4, "value": 1 }
+      ],
+      "type": "text/x-moz-place-container",
+      "root": "mobileFolder",
+      "children": [
+        {
+          "guid": "a17yW6-nTxEJ",
+          "title": "Mozilla",
+          "index": 0,
+          "dateAdded": 1475084731959000,
+          "lastModified": 1475084731959000,
+          "id": 7,
+          "type": "text/x-moz-place",
+          "uri": "https://mozilla.org/"
+        },
+        {
+          "guid": "xV10h9Wi3FBM",
+          "title": "Bugzilla",
+          "index": 1,
+          "dateAdded": 1475084731961000,
+          "lastModified": 1475084731961000,
+          "id": 8,
+          "type": "text/x-moz-place",
+          "uri": "https://bugzilla.mozilla.org/"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/places/tests/unit/test_1085291.js b/toolkit/components/places/tests/unit/test_1085291.js
new file mode 100644
index 0000000000..b7ec4181f0
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_1085291.js
@@ -0,0 +1,48 @@
+add_task(async function () {
+  // test that nodes inserted by incremental update for bookmarks of all types
+  // have the extra bookmark properties (bookmarkGuid, dateAdded, lastModified).
+
+  // getFolderContents opens the root node.
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  ).root;
+
+  async function insertAndTest(bmInfo) {
+    bmInfo = await PlacesUtils.bookmarks.insert(bmInfo);
+    let node = root.getChild(root.childCount - 1);
+    Assert.equal(node.bookmarkGuid, bmInfo.guid);
+    Assert.equal(node.dateAdded, bmInfo.dateAdded * 1000);
+    Assert.equal(node.lastModified, bmInfo.lastModified * 1000);
+  }
+
+  // Normal bookmark.
+  await insertAndTest({
+    parentGuid: root.bookmarkGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    title: "Test Bookmark",
+    url: "http://test.url.tld",
+  });
+
+  // place: query
+  await insertAndTest({
+    parentGuid: root.bookmarkGuid,
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    title: "Test Query",
+    url: `place:parent=${PlacesUtils.bookmarks.menuGuid}`,
+  });
+
+  // folder
+  await insertAndTest({
+    parentGuid: root.bookmarkGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "Test Folder",
+  });
+
+  // separator
+  await insertAndTest({
+    parentGuid: root.bookmarkGuid,
+    type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+  });
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_1105208.js b/toolkit/components/places/tests/unit/test_1105208.js
new file mode 100644
index 0000000000..6b3f31f96a
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_1105208.js
@@ -0,0 +1,25 @@
+// Test that result node for folder shortcuts get the target folder title if
+// the shortcut itself has no title set.
+add_task(async function () {
+  let folder = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "fake",
+  });
+
+  let shortcutInfo = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: `place:parent=${folder.guid}`,
+  });
+
+  let unfiledRoot = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let shortcutNode = unfiledRoot.getChild(unfiledRoot.childCount - 1);
+  Assert.equal(shortcutNode.bookmarkGuid, shortcutInfo.guid);
+
+  Assert.equal(shortcutNode.title, folder.title);
+
+  unfiledRoot.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_1105866.js b/toolkit/components/places/tests/unit/test_1105866.js
new file mode 100644
index 0000000000..c387d9e853
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_1105866.js
@@ -0,0 +1,77 @@
+add_task(async function test_folder_shortcuts() {
+  let shortcutInfo = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: `place:parent=${PlacesUtils.bookmarks.toolbarGuid}`,
+  });
+
+  let unfiledRoot = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let shortcutNode = unfiledRoot.getChild(unfiledRoot.childCount - 1);
+  Assert.strictEqual(
+    shortcutNode.itemId,
+    await PlacesTestUtils.promiseItemId(shortcutInfo.guid)
+  );
+  Assert.strictEqual(
+    PlacesUtils.asQuery(shortcutNode).folderItemId,
+    await PlacesTestUtils.promiseItemId(PlacesUtils.bookmarks.toolbarGuid)
+  );
+  Assert.strictEqual(shortcutNode.bookmarkGuid, shortcutInfo.guid);
+  Assert.strictEqual(
+    PlacesUtils.asQuery(shortcutNode).targetFolderGuid,
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+
+  // test that a node added incrementally also behaves just as well.
+  shortcutInfo = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: `place:parent=${PlacesUtils.bookmarks.menuGuid}`,
+  });
+  shortcutNode = unfiledRoot.getChild(unfiledRoot.childCount - 1);
+  Assert.strictEqual(
+    shortcutNode.itemId,
+    await PlacesTestUtils.promiseItemId(shortcutInfo.guid)
+  );
+  Assert.strictEqual(
+    PlacesUtils.asQuery(shortcutNode).folderItemId,
+    await PlacesTestUtils.promiseItemId(PlacesUtils.bookmarks.menuGuid)
+  );
+  Assert.strictEqual(shortcutNode.bookmarkGuid, shortcutInfo.guid);
+  Assert.strictEqual(
+    PlacesUtils.asQuery(shortcutNode).targetFolderGuid,
+    PlacesUtils.bookmarks.menuGuid
+  );
+
+  unfiledRoot.containerOpen = false;
+});
+
+add_task(async function test_plain_folder() {
+  let folderInfo = await PlacesUtils.bookmarks.insert({
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+
+  let unfiledRoot = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  let lastChild = unfiledRoot.getChild(unfiledRoot.childCount - 1);
+  Assert.strictEqual(lastChild.bookmarkGuid, folderInfo.guid);
+  Assert.strictEqual(
+    PlacesUtils.asQuery(lastChild).targetFolderGuid,
+    folderInfo.guid
+  );
+});
+
+add_task(async function test_non_item_query() {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  Assert.strictEqual(root.itemId, -1);
+  Assert.strictEqual(PlacesUtils.asQuery(root).folderItemId, -1);
+  Assert.strictEqual(root.bookmarkGuid, "");
+  Assert.strictEqual(PlacesUtils.asQuery(root).targetFolderGuid, "");
+});
diff --git a/toolkit/components/places/tests/unit/test_1606731.js b/toolkit/components/places/tests/unit/test_1606731.js
new file mode 100644
index 0000000000..89e8ec0498
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_1606731.js
@@ -0,0 +1,21 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+let hs = PlacesUtils.history;
+
+/* Test for diacritic-insensitive history search */
+
+add_task(async function test_execute() {
+  const TEST_URL = "http://example.net/El_%C3%81rea_51";
+  const SEARCH_TERM = "area";
+  await PlacesTestUtils.addVisits(uri(TEST_URL));
+  let query = hs.getNewQuery();
+  query.searchTerms = SEARCH_TERM;
+  let options = hs.getNewQueryOptions();
+  let result = hs.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.ok(result.root.childCount == 1);
+});
diff --git a/toolkit/components/places/tests/unit/test_331487.js b/toolkit/components/places/tests/unit/test_331487.js
new file mode 100644
index 0000000000..2d4f5f8279
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_331487.js
@@ -0,0 +1,113 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get history service
+try {
+  var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+    Ci.nsINavHistoryService
+  );
+} catch (ex) {
+  do_throw("Could not get history service\n");
+}
+
+add_task(async function test_hierarchical_query() {
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "test folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "1 title",
+            url: "http://a1.com/",
+          },
+          {
+            title: "subfolder 1",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            children: [
+              {
+                title: "2 title",
+                url: "http://a2.com/",
+              },
+              {
+                title: "subfolder 2",
+                type: PlacesUtils.bookmarks.TYPE_FOLDER,
+                children: [
+                  {
+                    title: "3 title",
+                    url: "http://a3.com/",
+                  },
+                ],
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+
+  let [folderGuid, b1, sf1, b2, sf2, b3] = bookmarks.map(
+    bookmark => bookmark.guid
+  );
+
+  // bookmark query that should result in the "hierarchical" result
+  // because there is one query, one folder,
+  // no begin time, no end time, no domain, no uri, no search term
+  // and no max results.  See GetSimpleBookmarksQueryFolder()
+  // for more details.
+  var options = histsvc.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  var query = histsvc.getNewQuery();
+  query.setParents([folderGuid]);
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.getChild(0).bookmarkGuid, b1);
+  Assert.equal(root.getChild(1).bookmarkGuid, sf1);
+
+  // check the contents of the subfolder
+  var sf1Node = root.getChild(1);
+  sf1Node = sf1Node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  sf1Node.containerOpen = true;
+  Assert.equal(sf1Node.childCount, 2);
+  Assert.equal(sf1Node.getChild(0).bookmarkGuid, b2);
+  Assert.equal(sf1Node.getChild(1).bookmarkGuid, sf2);
+
+  // check the contents of the subfolder's subfolder
+  var sf2Node = sf1Node.getChild(1);
+  sf2Node = sf2Node.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  sf2Node.containerOpen = true;
+  Assert.equal(sf2Node.childCount, 1);
+  Assert.equal(sf2Node.getChild(0).bookmarkGuid, b3);
+
+  sf2Node.containerOpen = false;
+  sf1Node.containerOpen = false;
+  root.containerOpen = false;
+
+  // bookmark query that should result in a flat list
+  // because we specified max results
+  options = histsvc.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+  options.maxResults = 10;
+  query = histsvc.getNewQuery();
+  query.setParents([folderGuid]);
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 3);
+  Assert.equal(root.getChild(0).bookmarkGuid, b1);
+  Assert.equal(root.getChild(1).bookmarkGuid, b2);
+  Assert.equal(root.getChild(2).bookmarkGuid, b3);
+  root.containerOpen = false;
+
+  // XXX TODO
+  // test that if we have: more than one query,
+  // multiple folders, a begin time, an end time, a domain, a uri
+  // or a search term, that we get the (correct) flat list results
+  // (like we do when specified maxResults)
+});
diff --git a/toolkit/components/places/tests/unit/test_384370.js b/toolkit/components/places/tests/unit/test_384370.js
new file mode 100644
index 0000000000..cc760e3276
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_384370.js
@@ -0,0 +1,188 @@
+var tagData = [
+  { uri: uri("http://slint.us"), tags: ["indie", "kentucky", "music"] },
+  {
+    uri: uri("http://en.wikipedia.org/wiki/Diplodocus"),
+    tags: ["dinosaur", "dj", "rad word"],
+  },
+];
+
+var bookmarkData = [
+  { uri: uri("http://slint.us"), title: "indie,kentucky,music" },
+  {
+    uri: uri("http://en.wikipedia.org/wiki/Diplodocus"),
+    title: "dinosaur,dj,rad word",
+  },
+];
+
+/*
+  HTML+FEATURES SUMMARY:
+  - import legacy bookmarks
+  - export as json, import, test (tests integrity of html > json)
+  - export as html, import, test (tests integrity of json > html)
+
+  BACKUP/RESTORE SUMMARY:
+  - create a bookmark in each root
+  - tag multiple URIs with multiple tags
+  - export as json, import, test
+*/
+add_task(async function () {
+  // Remove eventual bookmarks.exported.json.
+  let jsonFile = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.json"
+  );
+  await IOUtils.remove(jsonFile, { ignoreAbsent: true });
+
+  // Test importing a pre-Places canonical bookmarks file.
+  // Note: we do not empty the db before this import to catch bugs like 380999
+  let htmlFile = PathUtils.join(do_get_cwd().path, "bookmarks.preplaces.html");
+  await BookmarkHTMLUtils.importFromFile(htmlFile, { replace: true });
+
+  // Populate the database.
+  for (let { uri, tags } of tagData) {
+    PlacesUtils.tagging.tagURI(uri, tags);
+  }
+  for (let { uri, title } of bookmarkData) {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: uri,
+      title,
+    });
+  }
+  for (let { uri, title } of bookmarkData) {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+      url: uri,
+      title,
+    });
+  }
+
+  await validate("initial database");
+
+  // Test exporting a Places canonical json file.
+  // 1. export to bookmarks.exported.json
+  await BookmarkJSONUtils.exportToFile(jsonFile);
+  info("exported json");
+
+  // 2. empty bookmarks db
+  // 3. import bookmarks.exported.json
+  await BookmarkJSONUtils.importFromFile(jsonFile, { replace: true });
+  info("imported json");
+
+  // 4. run the test-suite
+  await validate("re-imported json");
+  info("validated import");
+});
+
+async function validate(infoMsg) {
+  info(`Validating ${infoMsg}: testMenuBookmarks`);
+  await testMenuBookmarks();
+  info(`Validating ${infoMsg}: testToolbarBookmarks`);
+  await testToolbarBookmarks();
+  info(`Validating ${infoMsg}: testUnfiledBookmarks`);
+  testUnfiledBookmarks();
+  info(`Validating ${infoMsg}: testTags`);
+  testTags();
+  await PlacesTestUtils.promiseAsyncUpdates();
+}
+
+// Tests a bookmarks datastore that has a set of bookmarks, etc
+// that flex each supported field and feature.
+async function testMenuBookmarks() {
+  let root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.menuGuid).root;
+  Assert.equal(root.childCount, 3);
+
+  let separatorNode = root.getChild(1);
+  Assert.equal(separatorNode.type, separatorNode.RESULT_TYPE_SEPARATOR);
+
+  let folderNode = root.getChild(2);
+  Assert.equal(folderNode.type, folderNode.RESULT_TYPE_FOLDER);
+  Assert.equal(folderNode.title, "test");
+  let folder = await PlacesUtils.bookmarks.fetch(folderNode.bookmarkGuid);
+  Assert.equal(folder.dateAdded.getTime(), 1177541020000);
+
+  Assert.equal(PlacesUtils.asQuery(folderNode).hasChildren, true);
+
+  // open test folder, and test the children
+  folderNode.containerOpen = true;
+  Assert.equal(folderNode.childCount, 1);
+
+  let bookmarkNode = folderNode.getChild(0);
+  Assert.equal("http://test/post", bookmarkNode.uri);
+  Assert.equal("test post keyword", bookmarkNode.title);
+  Assert.equal(bookmarkNode.dateAdded, 1177375336000000);
+
+  let entry = await PlacesUtils.keywords.fetch({ url: bookmarkNode.uri });
+  Assert.equal("test", entry.keyword);
+  Assert.equal("hidden1%3Dbar&text1%3D%25s", entry.postData);
+
+  let pageInfo = await PlacesUtils.history.fetch(bookmarkNode.uri, {
+    includeAnnotations: true,
+  });
+  Assert.equal(
+    pageInfo.annotations.get(PlacesUtils.CHARSET_ANNO),
+    "ISO-8859-1",
+    "Should have the correct charset"
+  );
+
+  folderNode.containerOpen = false;
+  root.containerOpen = false;
+}
+
+async function testToolbarBookmarks() {
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid
+  ).root;
+
+  // child count (add 2 for pre-existing items, one of the feeds is skipped
+  // because it doesn't have href)
+  Assert.equal(root.childCount, bookmarkData.length + 2);
+
+  // Livemarks are no more supported but may still exist in old html files.
+  let legacyLivemarkNode = root.getChild(1);
+  Assert.equal("Latest Headlines", legacyLivemarkNode.title);
+  Assert.equal(
+    "http://en-us.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/",
+    legacyLivemarkNode.uri
+  );
+  Assert.equal(
+    legacyLivemarkNode.type,
+    Ci.nsINavHistoryResultNode.RESULT_TYPE_URI
+  );
+
+  // test added bookmark data
+  let bookmarkNode = root.getChild(2);
+  Assert.equal(bookmarkNode.uri, bookmarkData[0].uri.spec);
+  Assert.equal(bookmarkNode.title, bookmarkData[0].title);
+  bookmarkNode = root.getChild(3);
+  Assert.equal(bookmarkNode.uri, bookmarkData[1].uri.spec);
+  Assert.equal(bookmarkNode.title, bookmarkData[1].title);
+
+  root.containerOpen = false;
+}
+
+function testUnfiledBookmarks() {
+  let root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  ).root;
+  // child count (add 1 for pre-existing item)
+  Assert.equal(root.childCount, bookmarkData.length + 1);
+  for (let i = 1; i < root.childCount; ++i) {
+    let child = root.getChild(i);
+    Assert.equal(child.uri, bookmarkData[i - 1].uri.spec);
+    Assert.equal(child.title, bookmarkData[i - 1].title);
+    if (child.tags) {
+      Assert.equal(child.tags, bookmarkData[i - 1].title);
+    }
+  }
+  root.containerOpen = false;
+}
+
+function testTags() {
+  for (let { uri, tags } of tagData) {
+    info("Test tags for " + uri.spec + ": " + tags + "\n");
+    let foundTags = PlacesUtils.tagging.getTagsForURI(uri);
+    Assert.equal(foundTags.length, tags.length);
+    Assert.ok(tags.every(tag => foundTags.includes(tag)));
+  }
+}
diff --git a/toolkit/components/places/tests/unit/test_385397.js b/toolkit/components/places/tests/unit/test_385397.js
new file mode 100644
index 0000000000..7746b89657
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_385397.js
@@ -0,0 +1,152 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const TOTAL_SITES = 20;
+
+add_task(async function test_execute() {
+  let now = (Date.now() - 10000) * 1000;
+
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let site = "http://www.test-" + i + ".com/";
+    let testURI = uri(site);
+    let testImageURI = uri(site + "blank.gif");
+    let when = now + i * TOTAL_SITES * 1000;
+    await PlacesTestUtils.addVisits([
+      { uri: testURI, visitDate: when, transition: TRANSITION_TYPED },
+      {
+        uri: testImageURI,
+        visitDate: when + 1000,
+        transition: TRANSITION_EMBED,
+      },
+      {
+        uri: testImageURI,
+        visitDate: when + 2000,
+        transition: TRANSITION_FRAMED_LINK,
+      },
+      { uri: testURI, visitDate: when + 3000, transition: TRANSITION_LINK },
+    ]);
+  }
+
+  // verify our visits AS_VISIT, ordered by date descending
+  // including hidden
+  // we should get 80 visits:
+  // http://www.test-19.com/
+  // http://www.test-19.com/blank.gif
+  // http://www.test-19.com/
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-0.com/
+  // http://www.test-0.com/blank.gif
+  // http://www.test-0.com/
+  // http://www.test-0.com/
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.resultType = options.RESULTS_AS_VISIT;
+  options.includeHidden = true;
+  let root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  let cc = root.childCount;
+  // Embed visits are not added to the database, thus they won't appear.
+  Assert.equal(cc, 3 * TOTAL_SITES);
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let index = i * 3;
+    let node = root.getChild(index);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+    node = root.getChild(++index);
+    Assert.equal(node.uri, site + "blank.gif");
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+    node = root.getChild(++index);
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+
+  // verify our visits AS_VISIT, ordered by date descending
+  // we should get 40 visits:
+  // http://www.test-19.com/
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-0.com/
+  // http://www.test-0.com/
+  options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.resultType = options.RESULTS_AS_VISIT;
+  root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  cc = root.childCount;
+  // 2 * TOTAL_SITES because we count the TYPED and LINK, but not EMBED or FRAMED
+  Assert.equal(cc, 2 * TOTAL_SITES);
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let index = i * 2;
+    let node = root.getChild(index);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+    node = root.getChild(++index);
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+
+  // test our optimized query for the places menu
+  // place:type=0&sort=4&maxResults=10
+  // verify our visits AS_URI, ordered by date descending
+  // we should get 10 visits:
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-10.com/
+  options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.maxResults = 10;
+  options.resultType = options.RESULTS_AS_URI;
+  root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  cc = root.childCount;
+  Assert.equal(cc, options.maxResults);
+  for (let i = 0; i < cc; i++) {
+    let node = root.getChild(i);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+
+  // test without a maxResults, which executes a different query
+  // but the first 10 results should be the same.
+  // verify our visits AS_URI, ordered by date descending
+  // we should get 20 visits, but the first 10 should be
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-10.com/
+  options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.resultType = options.RESULTS_AS_URI;
+  root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  cc = root.childCount;
+  Assert.equal(cc, TOTAL_SITES);
+  for (let i = 0; i < 10; i++) {
+    let node = root.getChild(i);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_399266.js b/toolkit/components/places/tests/unit/test_399266.js
new file mode 100644
index 0000000000..6f99c710f8
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_399266.js
@@ -0,0 +1,82 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const TOTAL_SITES = 20;
+
+add_task(async function test_execute() {
+  let places = [];
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    for (let j = 0; j <= i; j++) {
+      places.push({
+        uri: uri("http://www.test-" + i + ".com/"),
+        transition: TRANSITION_TYPED,
+      });
+      // because these are embedded visits, they should not show up on our
+      // query results.  If they do, we have a problem.
+      places.push({
+        uri: uri("http://www.hidden.com/hidden.gif"),
+        transition: TRANSITION_EMBED,
+      });
+      places.push({
+        uri: uri("http://www.alsohidden.com/hidden.gif"),
+        transition: TRANSITION_FRAMED_LINK,
+      });
+    }
+  }
+  await PlacesTestUtils.addVisits(places);
+
+  // test our optimized query for the "Most Visited" item
+  // in the "Smart Bookmarks" folder
+  // place:queryType=0&sort=8&maxResults=10
+  // verify our visits AS_URI, ordered by visit count descending
+  // we should get 10 visits:
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-10.com/
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_VISITCOUNT_DESCENDING;
+  options.maxResults = 10;
+  options.resultType = options.RESULTS_AS_URI;
+  let root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  let cc = root.childCount;
+  Assert.equal(cc, options.maxResults);
+  for (let i = 0; i < cc; i++) {
+    let node = root.getChild(i);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+
+  // test without a maxResults, which executes a different query
+  // but the first 10 results should be the same.
+  // verify our visits AS_URI, ordered by visit count descending
+  // we should get 20 visits, but the first 10 should be
+  // http://www.test-19.com/
+  // ...
+  // http://www.test-10.com/
+  options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_VISITCOUNT_DESCENDING;
+  options.resultType = options.RESULTS_AS_URI;
+  root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  cc = root.childCount;
+  Assert.equal(cc, TOTAL_SITES);
+  for (let i = 0; i < 10; i++) {
+    let node = root.getChild(i);
+    let site = "http://www.test-" + (TOTAL_SITES - 1 - i) + ".com/";
+    Assert.equal(node.uri, site);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_402799.js b/toolkit/components/places/tests/unit/test_402799.js
new file mode 100644
index 0000000000..f621911cce
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_402799.js
@@ -0,0 +1,60 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get history services
+try {
+  var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+    Ci.nsINavHistoryService
+  );
+} catch (ex) {
+  do_throw("Could not get history services\n");
+}
+
+// Get tagging service
+try {
+  var tagssvc = Cc["@mozilla.org/browser/tagging-service;1"].getService(
+    Ci.nsITaggingService
+  );
+} catch (ex) {
+  do_throw("Could not get tagging service\n");
+}
+
+add_task(async function test_query_only_returns_bookmarks_not_tags() {
+  const url = "http://foo.bar/";
+
+  // create 2 bookmarks on the same uri
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "title 1",
+    url,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "title 2",
+    url,
+  });
+  // add some tags
+  tagssvc.tagURI(uri(url), ["foo", "bar", "foobar", "foo bar"]);
+
+  // check that a generic bookmark query returns only real bookmarks
+  let options = histsvc.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+
+  let query = histsvc.getNewQuery();
+  let result = histsvc.executeQuery(query, options);
+  let root = result.root;
+
+  root.containerOpen = true;
+  let cc = root.childCount;
+  Assert.equal(cc, 2);
+  let node1 = root.getChild(0);
+  node1 = await PlacesUtils.bookmarks.fetch(node1.bookmarkGuid);
+  Assert.equal(node1.parentGuid, PlacesUtils.bookmarks.menuGuid);
+  let node2 = root.getChild(1);
+  node2 = await PlacesUtils.bookmarks.fetch(node2.bookmarkGuid);
+  Assert.equal(node2.parentGuid, PlacesUtils.bookmarks.toolbarGuid);
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_412132.js b/toolkit/components/places/tests/unit/test_412132.js
new file mode 100644
index 0000000000..65653b5c0a
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_412132.js
@@ -0,0 +1,181 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * TEST DESCRIPTION:
+ *
+ * Tests patch to Bug 412132:
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=412132
+ */
+
+const TEST_URL0 = "http://example.com/";
+const TEST_URL1 = "http://example.com/1";
+const TEST_URL2 = "http://example.com/2";
+
+add_task(async function changeuri_unvisited_bookmark() {
+  info(
+    "After changing URI of bookmark, frecency of bookmark's " +
+      "original URI should be zero if original URI is unvisited and " +
+      "no longer bookmarked."
+  );
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URL1,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL1,
+    }),
+    0,
+    "Bookmarked => frecency of URI should be != 0"
+  );
+
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    url: TEST_URL2,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL1,
+    }),
+    0,
+    "Unvisited URI no longer bookmarked => frecency should = 0"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function changeuri_visited_bookmark() {
+  info(
+    "After changing URI of bookmark, frecency of bookmark's " +
+      "original URI should not be zero if original URI is visited."
+  );
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URL1,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL1,
+    }),
+    0,
+    "Bookmarked => frecency of URI should be != 0"
+  );
+
+  await PlacesTestUtils.addVisits(TEST_URL1);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    url: TEST_URL2,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL1,
+    }),
+    0,
+    "*Visited* URI no longer bookmarked => frecency should != 0"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function changeuri_bookmark_still_bookmarked() {
+  info(
+    "After changing URI of bookmark, frecency of bookmark's " +
+      "original URI should not be zero if original URI is still " +
+      "bookmarked."
+  );
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark 1 title",
+    url: TEST_URL1,
+  });
+
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark 2 title",
+    url: TEST_URL1,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL1,
+    }),
+    0,
+    "Bookmarked => frecency of URI should be != 0"
+  );
+
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    url: TEST_URL2,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  info("URI still bookmarked => frecency should != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URL2,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function changeuri_nonexistent_bookmark() {
+  // Try a bogus guid.
+  await Assert.rejects(
+    PlacesUtils.bookmarks.update({
+      guid: "ABCDEDFGHIJK",
+      url: TEST_URL2,
+    }),
+    /No bookmarks found for the provided GUID/,
+    "Changing the URI of a non-existent bookmark should fail."
+  );
+
+  // Now add a bookmark, delete it, and check.
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URL0,
+  });
+
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+
+  await Assert.rejects(
+    PlacesUtils.bookmarks.update({
+      guid: bookmark.guid,
+      url: TEST_URL2,
+    }),
+    /No bookmarks found for the provided GUID/,
+    "Changing the URI of a non-existent bookmark should fail."
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/unit/test_415460.js b/toolkit/components/places/tests/unit/test_415460.js
new file mode 100644
index 0000000000..3f0f7a1edb
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_415460.js
@@ -0,0 +1,37 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var hs = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+  Ci.nsINavHistoryService
+);
+
+/**
+ * Checks to see that a search has exactly one result in the database.
+ *
+ * @param aTerms
+ *        The terms to search for.
+ * @returns true if the search returns one result, false otherwise.
+ */
+function search_has_result(aTerms) {
+  var options = hs.getNewQueryOptions();
+  options.maxResults = 1;
+  options.resultType = options.RESULTS_AS_URI;
+  var query = hs.getNewQuery();
+  query.searchTerms = aTerms;
+  var result = hs.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var cc = root.childCount;
+  root.containerOpen = false;
+  return cc == 1;
+}
+
+add_task(async function test_execute() {
+  const SEARCH_TERM = "ユニコード";
+  const TEST_URL = "http://example.com/" + SEARCH_TERM + "/";
+  await PlacesTestUtils.addVisits(uri(TEST_URL));
+  Assert.ok(search_has_result(SEARCH_TERM));
+});
diff --git a/toolkit/components/places/tests/unit/test_415757.js b/toolkit/components/places/tests/unit/test_415757.js
new file mode 100644
index 0000000000..a069bc6aa3
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_415757.js
@@ -0,0 +1,92 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Checks to see that a URI is in the database.
+ *
+ * @param aURI
+ *        The URI to check.
+ * @returns true if the URI is in the DB, false otherwise.
+ */
+function uri_in_db(aURI) {
+  var options = PlacesUtils.history.getNewQueryOptions();
+  options.maxResults = 1;
+  options.resultType = options.RESULTS_AS_URI;
+  var query = PlacesUtils.history.getNewQuery();
+  query.uri = aURI;
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var cc = root.childCount;
+  root.containerOpen = false;
+  return cc == 1;
+}
+
+const TOTAL_SITES = 20;
+
+// main
+add_task(async function test_execute() {
+  // add pages to global history
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let uri = "http://www.test-" + i + ".com/";
+    let when = Date.now() * 1000 + i * TOTAL_SITES;
+    await PlacesTestUtils.addVisits({ uri, visitDate: when });
+  }
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let uri = "http://www.test.com/" + i + "/";
+    let when = Date.now() * 1000 + i * TOTAL_SITES;
+    await PlacesTestUtils.addVisits({ uri, visitDate: when });
+  }
+
+  // set a page annotation on one of the urls that will be removed
+  var testAnnoDeletedURI = "http://www.test.com/1/";
+  var testAnnoDeletedName = "foo";
+  var testAnnoDeletedValue = "bar";
+  await PlacesUtils.history.update({
+    url: testAnnoDeletedURI,
+    annotations: new Map([[testAnnoDeletedName, testAnnoDeletedValue]]),
+  });
+
+  // set a page annotation on one of the urls that will NOT be removed
+  var testAnnoRetainedURI = "http://www.test-1.com/";
+  var testAnnoRetainedName = "foo";
+  var testAnnoRetainedValue = "bar";
+  await PlacesUtils.history.update({
+    url: testAnnoRetainedURI,
+    annotations: new Map([[testAnnoRetainedName, testAnnoRetainedValue]]),
+  });
+
+  // remove pages from www.test.com
+  await PlacesUtils.history.removeByFilter({ host: "www.test.com" });
+
+  // check that all pages in www.test.com have been removed
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let site = "http://www.test.com/" + i + "/";
+    let testURI = uri(site);
+    Assert.ok(!uri_in_db(testURI));
+  }
+
+  // check that all pages in www.test-X.com have NOT been removed
+  for (let i = 0; i < TOTAL_SITES; i++) {
+    let site = "http://www.test-" + i + ".com/";
+    let testURI = uri(site);
+    Assert.ok(uri_in_db(testURI));
+  }
+
+  // check that annotation on the removed item does not exists
+  await assertNoOrphanPageAnnotations();
+
+  // check that annotation on the NOT removed item still exists
+  let pageInfo = await PlacesUtils.history.fetch(testAnnoRetainedURI, {
+    includeAnnotations: true,
+  });
+
+  Assert.equal(
+    pageInfo.annotations.get(testAnnoRetainedName),
+    testAnnoRetainedValue,
+    "Should have kept the annotation for the non-removed items"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_419792_node_tags_property.js b/toolkit/components/places/tests/unit/test_419792_node_tags_property.js
new file mode 100644
index 0000000000..53b0b74fce
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_419792_node_tags_property.js
@@ -0,0 +1,52 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// get services
+var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+  Ci.nsINavHistoryService
+);
+var tagssvc = Cc["@mozilla.org/browser/tagging-service;1"].getService(
+  Ci.nsITaggingService
+);
+
+add_task(async function test_query_node_tags_property() {
+  // get toolbar node
+  var options = histsvc.getNewQueryOptions();
+  var query = histsvc.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var result = histsvc.executeQuery(query, options);
+  var toolbarNode = result.root;
+  toolbarNode.containerOpen = true;
+
+  // add a bookmark
+  var bookmarkURI = uri("http://foo.com");
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "",
+    url: bookmarkURI,
+  });
+
+  // get the node for the new bookmark
+  var node = toolbarNode.getChild(toolbarNode.childCount - 1);
+  Assert.equal(node.bookmarkGuid, bookmark.guid);
+
+  // confirm there's no tags via the .tags property
+  Assert.equal(node.tags, null);
+
+  // add a tag
+  tagssvc.tagURI(bookmarkURI, ["foo"]);
+  Assert.equal(node.tags, "foo");
+
+  // add another tag, to test delimiter and sorting
+  tagssvc.tagURI(bookmarkURI, ["bar"]);
+  Assert.equal(node.tags, "bar,foo");
+
+  // remove the tags, confirming the property is cleared
+  tagssvc.untagURI(bookmarkURI, null);
+  Assert.equal(node.tags, null);
+
+  toolbarNode.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_425563.js b/toolkit/components/places/tests/unit/test_425563.js
new file mode 100644
index 0000000000..8ecf8bbcc8
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_425563.js
@@ -0,0 +1,76 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_execute() {
+  let count_visited_URIs = [
+    "http://www.test-link.com/",
+    "http://www.test-typed.com/",
+    "http://www.test-bookmark.com/",
+    "http://www.test-redirect-permanent.com/",
+    "http://www.test-redirect-temporary.com/",
+  ];
+
+  let notcount_visited_URIs = [
+    "http://www.test-download.com/",
+    "http://www.test-framed.com/",
+    "http://www.test-reload.com/",
+  ];
+
+  // add visits, one for each transition type
+  await PlacesTestUtils.addVisits([
+    { uri: uri("http://www.test-link.com/"), transition: TRANSITION_LINK },
+    { uri: uri("http://www.test-typed.com/"), transition: TRANSITION_TYPED },
+    {
+      uri: uri("http://www.test-bookmark.com/"),
+      transition: TRANSITION_BOOKMARK,
+    },
+    {
+      uri: uri("http://www.test-framed.com/"),
+      transition: TRANSITION_FRAMED_LINK,
+    },
+    {
+      uri: uri("http://www.test-redirect-permanent.com/"),
+      transition: TRANSITION_REDIRECT_PERMANENT,
+    },
+    {
+      uri: uri("http://www.test-redirect-temporary.com/"),
+      transition: TRANSITION_REDIRECT_TEMPORARY,
+    },
+    {
+      uri: uri("http://www.test-download.com/"),
+      transition: TRANSITION_DOWNLOAD,
+    },
+    { uri: uri("http://www.test-reload.com/"), transition: TRANSITION_RELOAD },
+  ]);
+
+  // check that all links are marked as visited
+  for (let visited_uri of count_visited_URIs) {
+    Assert.ok(await PlacesUtils.history.hasVisits(uri(visited_uri)));
+  }
+  for (let visited_uri of notcount_visited_URIs) {
+    Assert.ok(await PlacesUtils.history.hasVisits(uri(visited_uri)));
+  }
+
+  // check that visit_count does not take in count embed and downloads
+  // maxVisits query are directly binded to visit_count
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_VISITCOUNT_DESCENDING;
+  options.resultType = options.RESULTS_AS_VISIT;
+  options.includeHidden = true;
+  let query = PlacesUtils.history.getNewQuery();
+  query.minVisits = 1;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+
+  root.containerOpen = true;
+  let cc = root.childCount;
+  Assert.equal(cc, count_visited_URIs.length);
+
+  for (let i = 0; i < cc; i++) {
+    let node = root.getChild(i);
+    Assert.notEqual(count_visited_URIs.indexOf(node.uri), -1);
+  }
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_429505_remove_shortcuts.js b/toolkit/components/places/tests/unit/test_429505_remove_shortcuts.js
new file mode 100644
index 0000000000..d5926d0c17
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_429505_remove_shortcuts.js
@@ -0,0 +1,45 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+
+- add a folder
+- add a folder-shortcut to the new folder
+- query for the shortcut
+- remove the folder-shortcut
+- confirm the shortcut is removed from the query results
+
+*/
+
+add_task(async function test_query_with_remove_shortcut() {
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+
+  let query = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "",
+    url: `place:parent=${folder.guid}`,
+  });
+
+  var root = PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.toolbarGuid,
+    false,
+    true
+  ).root;
+
+  var oldCount = root.childCount;
+
+  await PlacesUtils.bookmarks.remove(query.guid);
+
+  Assert.equal(root.childCount, oldCount - 1);
+
+  root.containerOpen = false;
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
diff --git a/toolkit/components/places/tests/unit/test_433317_query_title_update.js b/toolkit/components/places/tests/unit/test_433317_query_title_update.js
new file mode 100644
index 0000000000..d8f69064d9
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_433317_query_title_update.js
@@ -0,0 +1,43 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_query_title_update() {
+  try {
+    var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+      Ci.nsINavHistoryService
+    );
+  } catch (ex) {
+    do_throw("Unable to initialize Places services");
+  }
+
+  // create a query bookmark
+  let bmQuery = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "test query",
+    url: "place:",
+  });
+
+  // query for that query
+  var options = histsvc.getNewQueryOptions();
+  let query = histsvc.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var queryNode = root.getChild(0);
+  Assert.equal(queryNode.title, "test query");
+
+  // change the title
+  await PlacesUtils.bookmarks.update({
+    guid: bmQuery.guid,
+    title: "foo",
+  });
+
+  // confirm the node was updated
+  Assert.equal(queryNode.title, "foo");
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_433525_hasChildren_crash.js b/toolkit/components/places/tests/unit/test_433525_hasChildren_crash.js
new file mode 100644
index 0000000000..231722e72b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_433525_hasChildren_crash.js
@@ -0,0 +1,52 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_execute() {
+  try {
+    var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+      Ci.nsINavHistoryService
+    );
+  } catch (ex) {
+    do_throw("Unable to initialize Places services");
+  }
+
+  // add a visit
+  var testURI = uri("http://test");
+  await PlacesTestUtils.addVisits(testURI);
+
+  // query for the visit
+  var options = histsvc.getNewQueryOptions();
+  options.maxResults = 1;
+  options.resultType = options.RESULTS_AS_URI;
+  var query = histsvc.getNewQuery();
+  query.uri = testURI;
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+
+  // check hasChildren while the container is closed
+  Assert.equal(root.hasChildren, true);
+
+  // now check via the saved search path
+  var queryURI = histsvc.queryToQueryString(query, options);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "test query",
+    url: queryURI,
+  });
+
+  // query for that query
+  options = histsvc.getNewQueryOptions();
+  query = histsvc.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  var queryNode = root.getChild(0);
+  Assert.equal(queryNode.title, "test query");
+  queryNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  Assert.equal(queryNode.hasChildren, true);
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_454977.js b/toolkit/components/places/tests/unit/test_454977.js
new file mode 100644
index 0000000000..aa6437988f
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_454977.js
@@ -0,0 +1,121 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Cache actual visit_count value, filled by add_visit, used by check_results
+var visit_count = 0;
+
+// Returns the Place ID corresponding to an added visit.
+async function task_add_visit(aURI, aVisitType) {
+  // Wait for a visits notification and get the visitId.
+  let visitId;
+  let visitsPromise = PlacesTestUtils.waitForNotification(
+    "page-visited",
+    visits => {
+      visitId = visits[0].visitId;
+      let { url } = visits[0];
+      return url == aURI.spec;
+    }
+  );
+
+  // Add visits.
+  await PlacesTestUtils.addVisits([
+    {
+      uri: aURI,
+      transition: aVisitType,
+    },
+  ]);
+
+  if (aVisitType != TRANSITION_EMBED) {
+    await visitsPromise;
+  }
+
+  // Increase visit_count if applicable
+  if (
+    aVisitType != 0 &&
+    aVisitType != TRANSITION_EMBED &&
+    aVisitType != TRANSITION_FRAMED_LINK &&
+    aVisitType != TRANSITION_DOWNLOAD &&
+    aVisitType != TRANSITION_RELOAD
+  ) {
+    visit_count++;
+  }
+
+  // Get the place id
+  if (visitId > 0) {
+    let sql = "SELECT place_id FROM moz_historyvisits WHERE id = ?1";
+    let stmt = DBConn().createStatement(sql);
+    stmt.bindByIndex(0, visitId);
+    Assert.ok(stmt.executeStep());
+    let placeId = stmt.getInt64(0);
+    stmt.finalize();
+    Assert.ok(placeId > 0);
+    return placeId;
+  }
+  return 0;
+}
+
+/**
+ * Checks for results consistency, using visit_count as constraint
+ * @param   aExpectedCount
+ *          Number of history results we are expecting (excluded hidden ones)
+ * @param   aExpectedCountWithHidden
+ *          Number of history results we are expecting (included hidden ones)
+ */
+function check_results(aExpectedCount, aExpectedCountWithHidden) {
+  let query = PlacesUtils.history.getNewQuery();
+  // used to check visit_count
+  query.minVisits = visit_count;
+  query.maxVisits = visit_count;
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_HISTORY;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  // Children without hidden ones
+  Assert.equal(root.childCount, aExpectedCount);
+  root.containerOpen = false;
+
+  // Execute again with includeHidden = true
+  // This will ensure visit_count is correct
+  options.includeHidden = true;
+  root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  // Children with hidden ones
+  Assert.equal(root.childCount, aExpectedCountWithHidden);
+  root.containerOpen = false;
+}
+
+// main
+
+add_task(async function test_execute() {
+  const TEST_URI = uri("http://test.mozilla.org/");
+
+  // Add a visit that force hidden
+  await task_add_visit(TEST_URI, TRANSITION_EMBED);
+  check_results(0, 0);
+
+  let placeId = await task_add_visit(TEST_URI, TRANSITION_FRAMED_LINK);
+  check_results(0, 1);
+
+  // Add a visit that force unhide and check the place id.
+  // - We expect that the place gets hidden = 0 while retaining the same
+  //   place id and a correct visit_count.
+  Assert.equal(await task_add_visit(TEST_URI, TRANSITION_TYPED), placeId);
+  check_results(1, 1);
+
+  // Add a visit that should not increase visit_count
+  Assert.equal(await task_add_visit(TEST_URI, TRANSITION_RELOAD), placeId);
+  check_results(1, 1);
+
+  // Add a visit that should not increase visit_count
+  Assert.equal(await task_add_visit(TEST_URI, TRANSITION_DOWNLOAD), placeId);
+  check_results(1, 1);
+
+  // Add a visit, check that hidden is not overwritten
+  // - We expect that the place has still hidden = 0, while retaining
+  //   correct visit_count.
+  await task_add_visit(TEST_URI, TRANSITION_EMBED);
+  check_results(1, 1);
+});
diff --git a/toolkit/components/places/tests/unit/test_463863.js b/toolkit/components/places/tests/unit/test_463863.js
new file mode 100644
index 0000000000..d524c00cd3
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_463863.js
@@ -0,0 +1,56 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * TEST DESCRIPTION:
+ *
+ * This test checks that in a basic history query all transition types visits
+ * appear but TRANSITION_EMBED and TRANSITION_FRAMED_LINK ones.
+ */
+
+var transitions = [
+  TRANSITION_LINK,
+  TRANSITION_TYPED,
+  TRANSITION_BOOKMARK,
+  TRANSITION_EMBED,
+  TRANSITION_FRAMED_LINK,
+  TRANSITION_REDIRECT_PERMANENT,
+  TRANSITION_REDIRECT_TEMPORARY,
+  TRANSITION_DOWNLOAD,
+];
+
+function runQuery(aResultType) {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = aResultType;
+  let root = PlacesUtils.history.executeQuery(
+    PlacesUtils.history.getNewQuery(),
+    options
+  ).root;
+  root.containerOpen = true;
+  let cc = root.childCount;
+  Assert.equal(cc, transitions.length - 2);
+
+  for (let i = 0; i < cc; i++) {
+    let node = root.getChild(i);
+    // Check that all transition types but EMBED and FRAMED appear in results
+    Assert.notEqual(node.uri.substr(6, 1), TRANSITION_EMBED);
+    Assert.notEqual(node.uri.substr(6, 1), TRANSITION_FRAMED_LINK);
+  }
+  root.containerOpen = false;
+}
+
+add_task(async function test_execute() {
+  // add visits, one for each transition type
+  for (let transition of transitions) {
+    await PlacesTestUtils.addVisits({
+      uri: uri("http://" + transition + ".mozilla.org/"),
+      transition,
+    });
+  }
+
+  runQuery(Ci.nsINavHistoryQueryOptions.RESULTS_AS_VISIT);
+  runQuery(Ci.nsINavHistoryQueryOptions.RESULTS_AS_URI);
+});
diff --git a/toolkit/components/places/tests/unit/test_485442_crash_bug_nsNavHistoryQuery_GetUri.js b/toolkit/components/places/tests/unit/test_485442_crash_bug_nsNavHistoryQuery_GetUri.js
new file mode 100644
index 0000000000..73bb5e9af4
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_485442_crash_bug_nsNavHistoryQuery_GetUri.js
@@ -0,0 +1,19 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = options.RESULT_TYPE_QUERY;
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(
+    PlacesUtils.asQuery(root).query.uri,
+    null,
+    "Should be null and not crash the browser"
+  );
+  root.containerOpen = false;
+}
diff --git a/toolkit/components/places/tests/unit/test_486978_sort_by_date_queries.js b/toolkit/components/places/tests/unit/test_486978_sort_by_date_queries.js
new file mode 100644
index 0000000000..221377e184
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_486978_sort_by_date_queries.js
@@ -0,0 +1,130 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * TEST DESCRIPTION:
+ *
+ * This test checks that setting a sort on a RESULTS_AS_DATE_QUERY query,
+ * children of inside containers are sorted accordingly.
+ */
+
+var hs = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+  Ci.nsINavHistoryService
+);
+
+// Will be inserted in this order, so last one will be the newest visit.
+var pages = [
+  "http://a.mozilla.org/1/",
+  "http://a.mozilla.org/2/",
+  "http://a.mozilla.org/3/",
+  "http://a.mozilla.org/4/",
+  "http://b.mozilla.org/5/",
+  "http://b.mozilla.org/6/",
+  "http://b.mozilla.org/7/",
+  "http://b.mozilla.org/8/",
+];
+
+add_task(async function test_initialize() {
+  // Add visits.
+  let now = new Date();
+  for (let pageIndex = 0; pageIndex < pages.length; ++pageIndex) {
+    let page = pages[pageIndex];
+    await PlacesTestUtils.addVisits({
+      uri: uri(page),
+      visitDate: new Date(now - (pages.length - pageIndex)),
+    });
+  }
+});
+
+/**
+ * Tests that sorting date query by none will sort by title asc.
+ */
+add_task(function () {
+  var options = hs.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_DATE_QUERY;
+  // This should sort by title asc.
+  options.sortingMode = options.SORT_BY_NONE;
+  var query = hs.getNewQuery();
+  var result = hs.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var dayContainer = root
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  dayContainer.containerOpen = true;
+
+  var cc = dayContainer.childCount;
+  Assert.equal(cc, pages.length);
+  for (var i = 0; i < cc; i++) {
+    var node = dayContainer.getChild(i);
+    Assert.equal(pages[i], node.uri);
+  }
+
+  dayContainer.containerOpen = false;
+  root.containerOpen = false;
+});
+
+/**
+ * Tests that sorting date query by date will sort accordingly.
+ */
+add_task(function () {
+  var options = hs.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_DATE_QUERY;
+  // This should sort by title asc.
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  var query = hs.getNewQuery();
+  var result = hs.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var dayContainer = root
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  dayContainer.containerOpen = true;
+
+  var cc = dayContainer.childCount;
+  Assert.equal(cc, pages.length);
+  for (var i = 0; i < cc; i++) {
+    var node = dayContainer.getChild(i);
+    Assert.equal(pages[pages.length - i - 1], node.uri);
+  }
+
+  dayContainer.containerOpen = false;
+  root.containerOpen = false;
+});
+
+/**
+ * Tests that sorting date site query by date will still sort by title asc.
+ */
+add_task(function () {
+  var options = hs.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_DATE_SITE_QUERY;
+  // This should sort by title asc.
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  var query = hs.getNewQuery();
+  var result = hs.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var dayContainer = root
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  dayContainer.containerOpen = true;
+  var siteContainer = dayContainer
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  Assert.equal(siteContainer.title, "a.mozilla.org");
+  siteContainer.containerOpen = true;
+
+  var cc = siteContainer.childCount;
+  Assert.equal(cc, pages.length / 2);
+  for (var i = 0; i < cc / 2; i++) {
+    var node = siteContainer.getChild(i);
+    Assert.equal(pages[i], node.uri);
+  }
+
+  siteContainer.containerOpen = false;
+  dayContainer.containerOpen = false;
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_536081.js b/toolkit/components/places/tests/unit/test_536081.js
new file mode 100644
index 0000000000..4105b09d1b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_536081.js
@@ -0,0 +1,35 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const TEST_URL = {
+  u: "http://www.google.com/search?q=testing%3Bthis&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-a",
+  s: "goog",
+};
+
+add_task(async function () {
+  print("Testing url: " + TEST_URL.u);
+  await PlacesTestUtils.addVisits(uri(TEST_URL.u));
+
+  let query = PlacesUtils.history.getNewQuery();
+  query.searchTerms = TEST_URL.s;
+  let options = PlacesUtils.history.getNewQueryOptions();
+
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  let cc = root.childCount;
+  Assert.equal(cc, 1);
+
+  print("Checking url is in the query.");
+  let node = root.getChild(0);
+  print("Found " + node.uri);
+
+  Assert.ok(await PlacesTestUtils.isPageInDB(TEST_URL.u));
+
+  root.containerOpen = false;
+  await PlacesUtils.history.remove(node.uri);
+
+  Assert.equal(false, await PlacesTestUtils.isPageInDB(TEST_URL.u));
+});
diff --git a/toolkit/components/places/tests/unit/test_PlacesDBUtils_removeOldCorruptDBs.js b/toolkit/components/places/tests/unit/test_PlacesDBUtils_removeOldCorruptDBs.js
new file mode 100644
index 0000000000..26ec85ffc4
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_PlacesDBUtils_removeOldCorruptDBs.js
@@ -0,0 +1,42 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const TEMP_FILES_TO_CREATE = 5;
+const LAST_MODIFICATION_DAY = [5, 10, 15, 20, 25];
+const TEST_CURRENT_TIME = Date.now();
+const MS_PER_DAY = 86400000;
+const RETAIN_DAYS = 14;
+
+async function createfiles() {
+  for (let i = 0; i < TEMP_FILES_TO_CREATE; i++) {
+    let setTime = TEST_CURRENT_TIME;
+    setTime -= LAST_MODIFICATION_DAY[i] * MS_PER_DAY;
+    let fileName = "places.sqlite" + (i > 0 ? "-" + i : "") + ".corrupt";
+    let filePath = PathUtils.join(PathUtils.profileDir, fileName);
+    await IOUtils.writeUTF8(filePath, "test-file-delete-me", {
+      tmpPath: filePath + ".tmp",
+    });
+    Assert.ok(await IOUtils.exists(filePath), "file created: " + filePath);
+    await IOUtils.setModificationTime(filePath, setTime);
+  }
+}
+
+add_task(async function removefiles() {
+  await createfiles();
+  await PlacesDBUtils.runTasks([PlacesDBUtils.removeOldCorruptDBs]);
+  for (let i = 0; i < TEMP_FILES_TO_CREATE; i++) {
+    let fileName = "places.sqlite" + (i > 0 ? "-" + i : "") + ".corrupt";
+    let filePath = PathUtils.join(PathUtils.profileDir, fileName);
+    if (LAST_MODIFICATION_DAY[i] >= RETAIN_DAYS) {
+      Assert.ok(
+        !(await IOUtils.exists(filePath)),
+        "Old corrupt file has been removed" + filePath
+      );
+    } else {
+      Assert.ok(
+        await IOUtils.exists(filePath),
+        "Files that are not old are not removed" + filePath
+      );
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_PlacesQuery_history.js b/toolkit/components/places/tests/unit/test_PlacesQuery_history.js
new file mode 100644
index 0000000000..9546e03730
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_PlacesQuery_history.js
@@ -0,0 +1,245 @@
+/* Any copyright is dedicated to the Public Domain.
+http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PlacesQuery } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesQuery.sys.mjs"
+);
+
+const placesQuery = new PlacesQuery();
+
+registerCleanupFunction(() => placesQuery.close());
+
+async function waitForUpdateHistoryTask(updateTask) {
+  const promise = new Promise(resolve =>
+    placesQuery.observeHistory(newHistory => resolve(newHistory))
+  );
+  await updateTask();
+  return promise;
+}
+
+add_task(async function test_visits_cache_is_updated() {
+  const now = new Date();
+  info("Insert the first visit.");
+  await PlacesUtils.history.insert({
+    url: "https://www.example.com/",
+    title: "Example Domain",
+    visits: [{ date: now }],
+  });
+  let history = await placesQuery.getHistory();
+  const mapKey = placesQuery.getStartOfDayTimestamp(now);
+  history = history.get(mapKey);
+  Assert.equal(history.length, 1);
+  Assert.equal(history[0].url, "https://www.example.com/");
+  Assert.equal(history[0].date.getTime(), now.getTime());
+  Assert.equal(history[0].title, "Example Domain");
+
+  info("Insert the next visit.");
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.insert({
+      url: "https://example.net/",
+      visits: [{ date: now }],
+    })
+  );
+  history = history.get(mapKey);
+  Assert.equal(history.length, 2);
+  Assert.equal(
+    history[0].url,
+    "https://example.net/",
+    "The most recent visit should come first."
+  );
+  Assert.equal(history[0].date.getTime(), now.getTime());
+
+  info("Remove the first visit.");
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.remove("https://www.example.com/")
+  );
+  history = history.get(mapKey);
+  Assert.equal(history.length, 1);
+  Assert.equal(history[0].url, "https://example.net/");
+
+  info("Remove all visits.");
+  history = await waitForUpdateHistoryTask(() => PlacesUtils.history.clear());
+  Assert.equal(history.size, 0);
+});
+
+add_task(async function test_filter_visits_by_age() {
+  const now = new Date();
+  await PlacesUtils.history.insertMany([
+    {
+      url: "https://www.example.com/",
+      visits: [{ date: new Date("2000-01-01T12:00:00") }],
+    },
+    {
+      url: "https://example.net/",
+      visits: [{ date: now }],
+    },
+  ]);
+  let history = await placesQuery.getHistory({ daysOld: 1 });
+  Assert.equal(history.size, 1, "The older visit should be excluded.");
+  Assert.equal(
+    history.get(placesQuery.getStartOfDayTimestamp(now))[0].url,
+    "https://example.net/"
+  );
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_visits_sort_option() {
+  const now = new Date();
+  info("Get history sorted by site.");
+  await PlacesUtils.history.insertMany([
+    { url: "https://www.reddit.com/", visits: [{ date: now }] },
+    { url: "https://twitter.com/", visits: [{ date: now }] },
+  ]);
+  let history = await placesQuery.getHistory({ sortBy: "site" });
+  ["reddit.com", "twitter.com"].forEach(domain =>
+    Assert.ok(history.has(domain))
+  );
+
+  info("Insert the next visit.");
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.insert({
+      url: "https://www.wikipedia.org/",
+      visits: [{ date: now }],
+    })
+  );
+  ["reddit.com", "twitter.com", "wikipedia.org"].forEach(domain =>
+    Assert.ok(history.has(domain))
+  );
+
+  info("Update the sort order.");
+  history = await placesQuery.getHistory({ sortBy: "date" });
+  const mapKey = placesQuery.getStartOfDayTimestamp(now);
+  Assert.equal(history.get(mapKey).length, 3);
+
+  info("Insert the next visit.");
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.insert({
+      url: "https://www.youtube.com/",
+      visits: [{ date: now }],
+    })
+  );
+  Assert.equal(history.get(mapKey).length, 4);
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_visits_limit_option() {
+  await PlacesUtils.history.insertMany([
+    {
+      url: "https://www.example.com/",
+      visits: [{ date: new Date() }],
+    },
+    {
+      url: "https://example.net/",
+      visits: [{ date: new Date() }],
+    },
+  ]);
+  let history = await placesQuery.getHistory({ limit: 1 });
+  Assert.equal(
+    [...history.values()].reduce((acc, { length }) => acc + length, 0),
+    1,
+    "Number of visits should be limited to 1."
+  );
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_dedupe_visits_by_url() {
+  const today = new Date();
+  const yesterday = new Date(
+    today.getFullYear(),
+    today.getMonth(),
+    today.getDate() - 1
+  );
+  await PlacesUtils.history.insertMany([
+    {
+      url: "https://www.example.com/",
+      visits: [{ date: yesterday }],
+    },
+    {
+      url: "https://www.example.com/",
+      visits: [{ date: today }],
+    },
+    {
+      url: "https://www.example.com/",
+      visits: [{ date: today }],
+    },
+  ]);
+  info("Get history sorted by date.");
+  let history = await placesQuery.getHistory({ sortBy: "date" });
+  Assert.equal(
+    history.get(placesQuery.getStartOfDayTimestamp(yesterday)).length,
+    1,
+    "There was only one visit from yesterday."
+  );
+  Assert.equal(
+    history.get(placesQuery.getStartOfDayTimestamp(today)).length,
+    1,
+    "The duplicate visit from today should be removed."
+  );
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.insert({
+      url: "https://www.example.com/",
+      visits: [{ date: today }],
+    })
+  );
+  Assert.equal(
+    history.get(placesQuery.getStartOfDayTimestamp(today)).length,
+    1,
+    "Visits inserted from `page-visited` events should be deduped."
+  );
+
+  info("Get history sorted by site.");
+  history = await placesQuery.getHistory({ sortBy: "site" });
+  Assert.equal(
+    history.get("example.com").length,
+    1,
+    "The duplicate visits for this site should be removed."
+  );
+  history = await waitForUpdateHistoryTask(() =>
+    PlacesUtils.history.insert({
+      url: "https://www.example.com/",
+      visits: [{ date: yesterday }],
+    })
+  );
+  const visits = history.get("example.com");
+  Assert.equal(
+    visits.length,
+    1,
+    "Visits inserted from `page-visited` events should be deduped."
+  );
+  Assert.equal(
+    visits[0].date.getTime(),
+    today.getTime(),
+    "Deduping keeps the most recent visit."
+  );
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_search_visits() {
+  const now = new Date();
+  await PlacesUtils.history.insertMany([
+    {
+      url: "https://www.example.com/",
+      title: "First Visit",
+      visits: [{ date: now }],
+    },
+    {
+      url: "https://example.net/",
+      title: "Second Visit",
+      visits: [{ date: now }],
+    },
+  ]);
+
+  let results = await placesQuery.searchHistory("Visit");
+  Assert.equal(results.length, 2, "Both visits match the search query.");
+
+  results = await placesQuery.searchHistory("First Visit");
+  Assert.equal(results.length, 1, "One visit matches the search query.");
+
+  results = await placesQuery.searchHistory("Bogus");
+  Assert.equal(results.length, 0, "Neither visit matches the search query.");
+
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/unit/test_PlacesUtils_isRootItem.js b/toolkit/components/places/tests/unit/test_PlacesUtils_isRootItem.js
new file mode 100644
index 0000000000..f626d437e0
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_PlacesUtils_isRootItem.js
@@ -0,0 +1,21 @@
+"use strict";
+
+const GUIDS = [
+  PlacesUtils.bookmarks.rootGuid,
+  ...PlacesUtils.bookmarks.userContentRoots,
+  PlacesUtils.bookmarks.tagsGuid,
+];
+
+add_task(async function test_isRootItem() {
+  for (let guid of GUIDS) {
+    Assert.ok(
+      PlacesUtils.isRootItem(guid),
+      `Should correctly identify root item ${guid}`
+    );
+  }
+
+  Assert.ok(
+    !PlacesUtils.isRootItem("fakeguid1234"),
+    "Should not identify other items as root."
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_PlacesUtils_unwrapNodes_place.js b/toolkit/components/places/tests/unit/test_PlacesUtils_unwrapNodes_place.js
new file mode 100644
index 0000000000..8944dc22f4
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_PlacesUtils_unwrapNodes_place.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that unwrapNodes properly filters out place: uris from text flavors.
+
+add_task(function () {
+  let tests = [
+    // Single url.
+    ["place:type=0&sort=1:", PlacesUtils.TYPE_X_MOZ_URL],
+    // Multiple urls.
+    [
+      "place:type=0&sort=1:\nfirst\nplace:type=0&sort=1\nsecond",
+      PlacesUtils.TYPE_X_MOZ_URL,
+    ],
+    // Url == title.
+    ["place:type=0&sort=1:\nplace:type=0&sort=1", PlacesUtils.TYPE_X_MOZ_URL],
+    // Malformed.
+    [
+      "place:type=0&sort=1:\nplace:type=0&sort=1\nmalformed",
+      PlacesUtils.TYPE_X_MOZ_URL,
+    ],
+    // Single url.
+    ["place:type=0&sort=1:", PlacesUtils.TYPE_PLAINTEXT],
+    // Multiple urls.
+    ["place:type=0&sort=1:\nplace:type=0&sort=1", PlacesUtils.TYPE_PLAINTEXT],
+  ];
+  for (let [blob, type] of tests) {
+    Assert.deepEqual(
+      PlacesUtils.unwrapNodes(blob, type),
+      [],
+      "No valid entries should be found"
+    );
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_asyncExecuteLegacyQueries.js b/toolkit/components/places/tests/unit/test_asyncExecuteLegacyQueries.js
new file mode 100644
index 0000000000..084415fb37
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_asyncExecuteLegacyQueries.js
@@ -0,0 +1,84 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This is a test for asyncExecuteLegacyQuery API.
+
+add_task(async function test_history_query() {
+  let uri = "http://test.visit.mozilla.com/";
+  let title = "Test visit";
+  await PlacesTestUtils.addVisits({ uri, title });
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING;
+  let query = PlacesUtils.history.getNewQuery();
+
+  return new Promise(resolve => {
+    PlacesUtils.history.asyncExecuteLegacyQuery(query, options, {
+      handleResult(aResultSet) {
+        for (let row; (row = aResultSet.getNextRow()); ) {
+          try {
+            Assert.equal(row.getResultByIndex(1), uri);
+            Assert.equal(row.getResultByIndex(2), title);
+          } catch (e) {
+            do_throw("Error while fetching page data.");
+          }
+        }
+      },
+      handleError(aError) {
+        do_throw(
+          "Async execution error (" + aError.result + "): " + aError.message
+        );
+      },
+      handleCompletion(aReason) {
+        cleanupTest().then(resolve);
+      },
+    });
+  });
+});
+
+add_task(async function test_bookmarks_query() {
+  let url = "http://test.bookmark.mozilla.com/";
+  let title = "Test bookmark";
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title,
+    url,
+  });
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode =
+    Ci.nsINavHistoryQueryOptions.SORT_BY_LASTMODIFIED_DESCENDING;
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let query = PlacesUtils.history.getNewQuery();
+
+  return new Promise(resolve => {
+    PlacesUtils.history.asyncExecuteLegacyQuery(query, options, {
+      handleResult(aResultSet) {
+        for (let row; (row = aResultSet.getNextRow()); ) {
+          try {
+            Assert.equal(row.getResultByIndex(1), url);
+            Assert.equal(row.getResultByIndex(2), title);
+          } catch (e) {
+            do_throw("Error while fetching page data.");
+          }
+        }
+      },
+      handleError(aError) {
+        do_throw(
+          "Async execution error (" + aError.result + "): " + aError.message
+        );
+      },
+      handleCompletion(aReason) {
+        cleanupTest().then(resolve);
+      },
+    });
+  });
+});
+
+function cleanupTest() {
+  return Promise.all([
+    PlacesUtils.history.clear(),
+    PlacesUtils.bookmarks.eraseEverything(),
+  ]);
+}
diff --git a/toolkit/components/places/tests/unit/test_async_transactions.js b/toolkit/components/places/tests/unit/test_async_transactions.js
new file mode 100644
index 0000000000..b0e9b292f3
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_async_transactions.js
@@ -0,0 +1,2125 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const bmsvc = PlacesUtils.bookmarks;
+const obsvc = PlacesUtils.observers;
+const tagssvc = PlacesUtils.tagging;
+const PT = PlacesTransactions;
+const menuGuid = PlacesUtils.bookmarks.menuGuid;
+
+ChromeUtils.defineESModuleGetters(this, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+// Create and add bookmarks observer.
+var observer = {
+  tagRelatedGuids: new Set(),
+
+  reset() {
+    this.itemsAdded = new Map();
+    this.itemsRemoved = new Map();
+    this.itemsMoved = new Map();
+    this.itemsKeywordChanged = new Map();
+    this.itemsTitleChanged = new Map();
+    this.itemsUrlChanged = new Map();
+  },
+
+  handlePlacesEvents(events) {
+    for (let event of events) {
+      switch (event.type) {
+        case "bookmark-added":
+          // Ignore tag items.
+          if (event.isTagging) {
+            this.tagRelatedGuids.add(event.guid);
+            return;
+          }
+
+          this.itemsAdded.set(event.guid, {
+            itemId: event.id,
+            parentGuid: event.parentGuid,
+            index: event.index,
+            itemType: event.itemType,
+            title: event.title,
+            url: event.url,
+          });
+          break;
+        case "bookmark-removed":
+          if (this.tagRelatedGuids.has(event.guid)) {
+            return;
+          }
+
+          this.itemsRemoved.set(event.guid, {
+            parentGuid: event.parentGuid,
+            index: event.index,
+            itemType: event.itemType,
+          });
+          break;
+        case "bookmark-moved":
+          this.itemsMoved.set(event.guid, {
+            oldParentGuid: event.oldParentGuid,
+            oldIndex: event.oldIndex,
+            newParentGuid: event.parentGuid,
+            newIndex: event.index,
+            itemType: event.itemType,
+          });
+          break;
+        case "bookmark-keyword-changed":
+          if (this.tagRelatedGuids.has(event.guid)) {
+            return;
+          }
+
+          this.itemsKeywordChanged.set(event.guid, {
+            keyword: event.keyword,
+          });
+          break;
+        case "bookmark-title-changed":
+          if (this.tagRelatedGuids.has(event.guid)) {
+            return;
+          }
+
+          this.itemsTitleChanged.set(event.guid, {
+            title: event.title,
+            parentGuid: event.parentGuid,
+          });
+          break;
+        case "bookmark-url-changed":
+          if (this.tagRelatedGuids.has(event.guid)) {
+            return;
+          }
+
+          this.itemsUrlChanged.set(event.guid, {
+            url: event.url,
+          });
+          break;
+      }
+    }
+  },
+};
+observer.reset();
+
+// index at which items should begin
+var bmStartIndex = 0;
+
+function run_test() {
+  observer.handlePlacesEvents = observer.handlePlacesEvents.bind(observer);
+  obsvc.addListener(
+    [
+      "bookmark-added",
+      "bookmark-removed",
+      "bookmark-moved",
+      "bookmark-keyword-changed",
+      "bookmark-title-changed",
+      "bookmark-url-changed",
+    ],
+    observer.handlePlacesEvents
+  );
+  registerCleanupFunction(function () {
+    obsvc.removeListener(
+      [
+        "bookmark-added",
+        "bookmark-removed",
+        "bookmark-moved",
+        "bookmark-keyword-changed",
+        "bookmark-title-changed",
+        "bookmark-url-changed",
+      ],
+      observer.handlePlacesEvents
+    );
+  });
+
+  run_next_test();
+}
+
+function sanityCheckTransactionHistory() {
+  Assert.ok(PT.undoPosition <= PT.length);
+
+  let check_entry_throws = f => {
+    try {
+      f();
+      do_throw("PT.entry should throw for invalid input");
+    } catch (ex) {}
+  };
+  check_entry_throws(() => PT.entry(-1));
+  check_entry_throws(() => PT.entry({}));
+  check_entry_throws(() => PT.entry(PT.length));
+
+  if (PT.undoPosition < PT.length) {
+    Assert.equal(PT.topUndoEntry, PT.entry(PT.undoPosition));
+  } else {
+    Assert.equal(null, PT.topUndoEntry);
+  }
+  if (PT.undoPosition > 0) {
+    Assert.equal(PT.topRedoEntry, PT.entry(PT.undoPosition - 1));
+  } else {
+    Assert.equal(null, PT.topRedoEntry);
+  }
+}
+
+function getTransactionsHistoryState() {
+  let history = [];
+  for (let i = 0; i < PT.length; i++) {
+    history.push(PT.entry(i));
+  }
+  return [history, PT.undoPosition];
+}
+
+function ensureUndoState(aExpectedEntries = [], aExpectedUndoPosition = 0) {
+  // ensureUndoState is called in various places during this test, so it's
+  // a good places to sanity-check the transaction-history APIs in all
+  // cases.
+  sanityCheckTransactionHistory();
+
+  let [actualEntries, actualUndoPosition] = getTransactionsHistoryState();
+  Assert.equal(actualEntries.length, aExpectedEntries.length);
+  Assert.equal(actualUndoPosition, aExpectedUndoPosition);
+
+  function checkEqualEntries(aExpectedEntry, aActualEntry) {
+    Assert.equal(aExpectedEntry.length, aActualEntry.length);
+    aExpectedEntry.forEach((t, i) => Assert.equal(t, aActualEntry[i]));
+  }
+  aExpectedEntries.forEach((e, i) => checkEqualEntries(e, actualEntries[i]));
+}
+
+function ensureItemsAdded(...items) {
+  let expectedResultsCount = items.length;
+
+  for (let item of items) {
+    if ("children" in item) {
+      expectedResultsCount += item.children.length;
+    }
+    Assert.ok(
+      observer.itemsAdded.has(item.guid),
+      `Should have the expected guid ${item.guid}`
+    );
+    let info = observer.itemsAdded.get(item.guid);
+    Assert.equal(
+      info.parentGuid,
+      item.parentGuid,
+      "Should have notified the correct parentGuid"
+    );
+    for (let propName of ["title", "index", "itemType"]) {
+      if (propName in item) {
+        Assert.equal(info[propName], item[propName]);
+      }
+    }
+    if ("url" in item) {
+      Assert.ok(
+        Services.io.newURI(info.url).equals(Services.io.newURI(item.url)),
+        "Should have the correct url"
+      );
+    }
+  }
+
+  Assert.equal(
+    observer.itemsAdded.size,
+    expectedResultsCount,
+    "Should have added the correct number of items"
+  );
+}
+
+function ensureItemsRemoved(...items) {
+  let expectedResultsCount = items.length;
+
+  for (let item of items) {
+    // We accept both guids and full info object here.
+    if (typeof item == "string") {
+      Assert.ok(
+        observer.itemsRemoved.has(item),
+        `Should have removed the expected guid ${item}`
+      );
+    } else {
+      if ("children" in item) {
+        expectedResultsCount += item.children.length;
+      }
+
+      Assert.ok(
+        observer.itemsRemoved.has(item.guid),
+        `Should have removed expected guid ${item.guid}`
+      );
+      let info = observer.itemsRemoved.get(item.guid);
+      Assert.equal(
+        info.parentGuid,
+        item.parentGuid,
+        "Should have notified the correct parentGuid"
+      );
+      if ("index" in item) {
+        Assert.equal(info.index, item.index);
+      }
+    }
+  }
+
+  Assert.equal(
+    observer.itemsRemoved.size,
+    expectedResultsCount,
+    "Should have removed the correct number of items"
+  );
+}
+
+function ensureItemsMoved(...items) {
+  Assert.equal(
+    observer.itemsMoved.size,
+    items.length,
+    "Should have received the correct number of moved notifications"
+  );
+  for (let item of items) {
+    Assert.ok(
+      observer.itemsMoved.has(item.guid),
+      `Observer should have a move for ${item.guid}`
+    );
+    let info = observer.itemsMoved.get(item.guid);
+    Assert.equal(
+      info.oldParentGuid,
+      item.oldParentGuid,
+      "Should have the correct old parent guid"
+    );
+    Assert.equal(
+      info.oldIndex,
+      item.oldIndex,
+      "Should have the correct old index"
+    );
+    Assert.equal(
+      info.newParentGuid,
+      item.newParentGuid,
+      "Should have the correct new parent guid"
+    );
+    Assert.equal(
+      info.newIndex,
+      item.newIndex,
+      "Should have the correct new index"
+    );
+  }
+}
+
+function ensureItemsKeywordChanged(...items) {
+  for (const item of items) {
+    Assert.ok(
+      observer.itemsKeywordChanged.has(item.guid),
+      `Observer should have a keyword changed for ${item.guid}`
+    );
+    const info = observer.itemsKeywordChanged.get(item.guid);
+    Assert.equal(info.keyword, item.keyword, "Should have the correct keyword");
+  }
+}
+
+function ensureItemsTitleChanged(...items) {
+  Assert.equal(
+    observer.itemsTitleChanged.size,
+    items.length,
+    "Should have received the correct number of bookmark-title-changed notifications"
+  );
+  for (const item of items) {
+    Assert.ok(
+      observer.itemsTitleChanged.has(item.guid),
+      `Observer should have a title changed for ${item.guid}`
+    );
+    const info = observer.itemsTitleChanged.get(item.guid);
+    Assert.equal(info.title, item.title, "Should have the correct title");
+    Assert.equal(
+      info.parentGuid,
+      item.parentGuid,
+      "Should have the correct parent guid"
+    );
+  }
+}
+
+function ensureItemsUrlChanged(...items) {
+  Assert.equal(
+    observer.itemsUrlChanged.size,
+    items.length,
+    "Should have received the correct number of bookmark-url-changed notifications"
+  );
+  for (const item of items) {
+    Assert.ok(
+      observer.itemsUrlChanged.has(item.guid),
+      `Observer should have a title changed for ${item.guid}`
+    );
+    const info = observer.itemsUrlChanged.get(item.guid);
+    Assert.equal(info.url, item.url, "Should have the correct url");
+  }
+}
+
+function ensureTagsForURI(aURI, aTags) {
+  let tagsSet = tagssvc.getTagsForURI(Services.io.newURI(aURI));
+  Assert.equal(tagsSet.length, aTags.length);
+  Assert.ok(aTags.every(t => tagsSet.includes(t)));
+}
+
+function createTestFolderInfo(
+  title = "Test Folder",
+  parentGuid = menuGuid,
+  children = undefined
+) {
+  let info = { parentGuid, title };
+  if (children) {
+    info.children = children;
+  }
+  return info;
+}
+
+function removeAllDatesInTree(tree) {
+  if ("lastModified" in tree) {
+    delete tree.lastModified;
+  }
+  if ("dateAdded" in tree) {
+    delete tree.dateAdded;
+  }
+
+  if (!tree.children) {
+    return;
+  }
+
+  for (let child of tree.children) {
+    removeAllDatesInTree(child);
+  }
+}
+
+// Checks if two bookmark trees (as returned by promiseBookmarksTree) are the
+// same.
+// false value for aCheckParentAndPosition is ignored if aIsRestoredItem is set.
+async function ensureEqualBookmarksTrees(
+  aOriginal,
+  aNew,
+  aIsRestoredItem = true,
+  aCheckParentAndPosition = false,
+  aIgnoreAllDates = false
+) {
+  // Note "id" is not-enumerable, and is therefore skipped by Object.keys (both
+  // ours and the one at deepEqual). This is fine for us because ids are not
+  // restored by Redo.
+  if (aIsRestoredItem) {
+    if (aIgnoreAllDates) {
+      removeAllDatesInTree(aOriginal);
+      removeAllDatesInTree(aNew);
+    } else if (!aOriginal.lastModified) {
+      // Ignore lastModified for newly created items, for performance reasons.
+      aNew.lastModified = aOriginal.lastModified;
+    }
+    Assert.deepEqual(aOriginal, aNew);
+    return;
+  }
+
+  for (let property of Object.keys(aOriginal)) {
+    if (property == "children") {
+      Assert.equal(aOriginal.children.length, aNew.children.length);
+      for (let i = 0; i < aOriginal.children.length; i++) {
+        await ensureEqualBookmarksTrees(
+          aOriginal.children[i],
+          aNew.children[i],
+          false,
+          true,
+          aIgnoreAllDates
+        );
+      }
+    } else if (property == "guid") {
+      // guid shouldn't be copied if the item was not restored.
+      Assert.notEqual(aOriginal.guid, aNew.guid);
+    } else if (property == "dateAdded") {
+      // dateAdded shouldn't be copied if the item was not restored.
+      Assert.ok(is_time_ordered(aOriginal.dateAdded, aNew.dateAdded));
+    } else if (property == "lastModified") {
+      // same same, except for the never-changed case
+      if (!aOriginal.lastModified) {
+        Assert.ok(!aNew.lastModified);
+      } else {
+        Assert.ok(is_time_ordered(aOriginal.lastModified, aNew.lastModified));
+      }
+    } else if (
+      aCheckParentAndPosition ||
+      (property != "parentGuid" && property != "index")
+    ) {
+      Assert.deepEqual(aOriginal[property], aNew[property]);
+    }
+  }
+}
+
+async function ensureBookmarksTreeRestoredCorrectly(
+  ...aOriginalBookmarksTrees
+) {
+  for (let originalTree of aOriginalBookmarksTrees) {
+    let restoredTree = await PlacesUtils.promiseBookmarksTree(
+      originalTree.guid
+    );
+    await ensureEqualBookmarksTrees(originalTree, restoredTree);
+  }
+}
+
+async function ensureBookmarksTreeRestoredCorrectlyExceptDates(
+  ...aOriginalBookmarksTrees
+) {
+  for (let originalTree of aOriginalBookmarksTrees) {
+    let restoredTree = await PlacesUtils.promiseBookmarksTree(
+      originalTree.guid
+    );
+    await ensureEqualBookmarksTrees(
+      originalTree,
+      restoredTree,
+      true,
+      false,
+      true
+    );
+  }
+}
+
+async function ensureNonExistent(...aGuids) {
+  for (let guid of aGuids) {
+    Assert.strictEqual(await PlacesUtils.promiseBookmarksTree(guid), null);
+  }
+}
+
+add_task(async function test_recycled_transactions() {
+  async function ensureTransactThrowsFor(aTransaction) {
+    let [txns, undoPosition] = getTransactionsHistoryState();
+    try {
+      await aTransaction.transact();
+      do_throw("Shouldn't be able to use the same transaction twice");
+    } catch (ex) {}
+    ensureUndoState(txns, undoPosition);
+  }
+
+  let txn_a = PT.NewFolder(createTestFolderInfo());
+  await txn_a.transact();
+  ensureUndoState([[txn_a]], 0);
+  await ensureTransactThrowsFor(txn_a);
+
+  await PT.undo();
+  ensureUndoState([[txn_a]], 1);
+  ensureTransactThrowsFor(txn_a);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+  ensureTransactThrowsFor(txn_a);
+
+  let txn_b = PT.NewFolder(createTestFolderInfo());
+  let results = await PT.batch([
+    txn_a, // Shouldn't be able to use the same transaction twice.
+    txn_b,
+  ]);
+  Assert.strictEqual(
+    results[0],
+    undefined,
+    "First transaction should fail as it can't be reused"
+  );
+  ensureUndoState([[txn_b]], 0);
+
+  await PT.undo();
+  ensureUndoState([[txn_b]], 1);
+  ensureTransactThrowsFor(txn_a);
+  ensureTransactThrowsFor(txn_b);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+  observer.reset();
+});
+
+add_task(async function test_new_folder_with_children() {
+  let folder_info = createTestFolderInfo(
+    "Test folder",
+    PlacesUtils.bookmarks.menuGuid,
+    [
+      {
+        url: "http://test_create_item.com",
+        title: "Test creating an item",
+      },
+    ]
+  );
+  ensureUndoState();
+  let txn = PT.NewFolder(folder_info);
+  folder_info.guid = await txn.transact();
+  let originalInfo = await PlacesUtils.promiseBookmarksTree(folder_info.guid);
+  let ensureDo = async function (aRedo = false) {
+    ensureUndoState([[txn]], 0);
+    ensureItemsAdded(folder_info);
+    if (aRedo) {
+      // Ignore lastModified in the comparison, for performance reasons.
+      originalInfo.lastModified = null;
+      await ensureBookmarksTreeRestoredCorrectlyExceptDates(originalInfo);
+    }
+    observer.reset();
+  };
+
+  let ensureUndo = () => {
+    ensureUndoState([[txn]], 1);
+    ensureItemsRemoved({
+      guid: folder_info.guid,
+      parentGuid: folder_info.parentGuid,
+      index: bmStartIndex,
+      children: [
+        {
+          title: "Test creating an item",
+          url: "http://test_create_item.com",
+        },
+      ],
+    });
+    observer.reset();
+  };
+
+  await ensureDo();
+  await PT.undo();
+  await ensureUndo();
+  await PT.redo();
+  await ensureDo(true);
+  await PT.undo();
+  ensureUndo();
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_new_bookmark() {
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test_create_item.com",
+    index: bmStartIndex,
+    title: "Test creating an item",
+  };
+
+  ensureUndoState();
+  let txn = PT.NewBookmark(bm_info);
+  bm_info.guid = await txn.transact();
+
+  let originalInfo = await PlacesUtils.promiseBookmarksTree(bm_info.guid);
+  let ensureDo = async function (aRedo = false) {
+    ensureUndoState([[txn]], 0);
+    await ensureItemsAdded(bm_info);
+    if (aRedo) {
+      await ensureBookmarksTreeRestoredCorrectly(originalInfo);
+    }
+    observer.reset();
+  };
+  let ensureUndo = () => {
+    ensureUndoState([[txn]], 1);
+    ensureItemsRemoved({
+      guid: bm_info.guid,
+      parentGuid: bm_info.parentGuid,
+      index: bmStartIndex,
+    });
+    observer.reset();
+  };
+
+  await ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo(true);
+  await ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_merge_create_folder_and_item() {
+  let folder_info = createTestFolderInfo();
+  let bm_info = {
+    url: "http://test_create_item_to_folder.com",
+    title: "Test Bookmark",
+    index: bmStartIndex,
+  };
+
+  let folderTxn = PT.NewFolder(folder_info);
+  let bmTxn;
+  let results = await PT.batch([
+    folderTxn,
+    previousResults => {
+      bm_info.parentGuid = previousResults[0];
+      return (bmTxn = PT.NewBookmark(bm_info));
+    },
+  ]);
+  folder_info.guid = results[0];
+  bm_info.guid = results[1];
+
+  let ensureDo = async function () {
+    ensureUndoState([[bmTxn, folderTxn]], 0);
+    await ensureItemsAdded(folder_info, bm_info);
+    observer.reset();
+  };
+
+  let ensureUndo = () => {
+    ensureUndoState([[bmTxn, folderTxn]], 1);
+    ensureItemsRemoved(folder_info, bm_info);
+    observer.reset();
+  };
+
+  await ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo();
+  await ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_move_items_to_folder() {
+  let folder_a_info = createTestFolderInfo("Folder A");
+  let bm_a_info = { url: "http://test_move_items.com", title: "Bookmark A" };
+  let bm_b_info = { url: "http://test_move_items.com", title: "Bookmark B" };
+
+  // Test moving items within the same folder.
+  let folder_a_txn = PT.NewFolder(folder_a_info);
+  let bm_a_txn, bm_b_txn;
+  let results = await PT.batch([
+    folder_a_txn,
+    previousResults => {
+      bm_a_info.parentGuid = previousResults[0];
+      return (bm_a_txn = PT.NewBookmark(bm_a_info));
+    },
+    previousResults => {
+      bm_b_info.parentGuid = previousResults[0];
+      return (bm_b_txn = PT.NewBookmark(bm_b_info));
+    },
+  ]);
+  console.log("results: " + results);
+  folder_a_info.guid = results[0];
+  bm_a_info.guid = results[1];
+  bm_b_info.guid = results[2];
+
+  ensureUndoState([[bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+
+  let moveTxn = PT.Move({
+    guid: bm_a_info.guid,
+    newParentGuid: folder_a_info.guid,
+  });
+  await moveTxn.transact();
+
+  let ensureDo = () => {
+    ensureUndoState([[moveTxn], [bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_a_info.guid,
+      newParentGuid: folder_a_info.guid,
+      oldIndex: 0,
+      newIndex: 1,
+    });
+    observer.reset();
+  };
+  let ensureUndo = () => {
+    ensureUndoState([[moveTxn], [bm_b_txn, bm_a_txn, folder_a_txn]], 1);
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_a_info.guid,
+      newParentGuid: folder_a_info.guid,
+      oldIndex: 1,
+      newIndex: 0,
+    });
+    observer.reset();
+  };
+
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo();
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  await PT.clearTransactionsHistory(false, true);
+  ensureUndoState([[bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+
+  // Test moving items between folders.
+  let folder_b_info = createTestFolderInfo("Folder B");
+  let folder_b_txn = PT.NewFolder(folder_b_info);
+  folder_b_info.guid = await folder_b_txn.transact();
+  ensureUndoState([[folder_b_txn], [bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+
+  moveTxn = PT.Move({
+    guid: bm_a_info.guid,
+    newParentGuid: folder_b_info.guid,
+    newIndex: bmsvc.DEFAULT_INDEX,
+  });
+  await moveTxn.transact();
+
+  ensureDo = () => {
+    ensureUndoState(
+      [[moveTxn], [folder_b_txn], [bm_b_txn, bm_a_txn, folder_a_txn]],
+      0
+    );
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_a_info.guid,
+      newParentGuid: folder_b_info.guid,
+      oldIndex: 0,
+      newIndex: 0,
+    });
+    observer.reset();
+  };
+  ensureUndo = () => {
+    ensureUndoState(
+      [[moveTxn], [folder_b_txn], [bm_b_txn, bm_a_txn, folder_a_txn]],
+      1
+    );
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_b_info.guid,
+      newParentGuid: folder_a_info.guid,
+      oldIndex: 0,
+      newIndex: 0,
+    });
+    observer.reset();
+  };
+
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo();
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  // Clean up
+  await PT.undo(); // folder_b_txn
+  await PT.undo(); // folder_a_txn + the bookmarks;
+  Assert.equal(observer.itemsRemoved.size, 4);
+  ensureUndoState(
+    [[moveTxn], [folder_b_txn], [bm_b_txn, bm_a_txn, folder_a_txn]],
+    3
+  );
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_move_multiple_items_to_folder() {
+  let folder_a_info = createTestFolderInfo("Folder A");
+  let bm_a_info = { url: "http://test_move_items.com", title: "Bookmark A" };
+  let bm_b_info = { url: "http://test_move_items.com", title: "Bookmark B" };
+  let bm_c_info = { url: "http://test_move_items.com", title: "Bookmark C" };
+
+  // Test moving items within the same folder.
+
+  let folder_a_txn = PT.NewFolder(folder_a_info);
+  let bm_a_txn, bm_b_txn, bm_c_txn;
+  let results = await PT.batch([
+    folder_a_txn,
+    previousResults => {
+      bm_a_info.parentGuid = previousResults[0];
+      return (bm_a_txn = PT.NewBookmark(bm_a_info));
+    },
+    previousResults => {
+      bm_b_info.parentGuid = previousResults[0];
+      return (bm_b_txn = PT.NewBookmark(bm_b_info));
+    },
+    previousResults => {
+      bm_c_info.parentGuid = previousResults[0];
+      return (bm_c_txn = PT.NewBookmark(bm_c_info));
+    },
+  ]);
+
+  folder_a_info.guid = results[0];
+  bm_a_info.guid = results[1];
+  bm_b_info.guid = results[2];
+  bm_c_info.guid = results[3];
+
+  ensureUndoState([[bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+
+  let moveTxn = PT.Move({
+    guids: [bm_a_info.guid, bm_b_info.guid],
+    newParentGuid: folder_a_info.guid,
+  });
+  await moveTxn.transact();
+
+  let ensureDo = () => {
+    ensureUndoState(
+      [[moveTxn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+      0
+    );
+    ensureItemsMoved(
+      {
+        guid: bm_a_info.guid,
+        oldParentGuid: folder_a_info.guid,
+        newParentGuid: folder_a_info.guid,
+        oldIndex: 0,
+        newIndex: 2,
+      },
+      {
+        guid: bm_b_info.guid,
+        oldParentGuid: folder_a_info.guid,
+        newParentGuid: folder_a_info.guid,
+        oldIndex: 1,
+        newIndex: 2,
+      }
+    );
+    observer.reset();
+  };
+  let ensureUndo = () => {
+    ensureUndoState(
+      [[moveTxn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+      1
+    );
+    ensureItemsMoved(
+      {
+        guid: bm_a_info.guid,
+        oldParentGuid: folder_a_info.guid,
+        newParentGuid: folder_a_info.guid,
+        oldIndex: 1,
+        newIndex: 0,
+      },
+      {
+        guid: bm_b_info.guid,
+        oldParentGuid: folder_a_info.guid,
+        newParentGuid: folder_a_info.guid,
+        oldIndex: 2,
+        newIndex: 1,
+      }
+    );
+    observer.reset();
+  };
+
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo();
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  await PT.clearTransactionsHistory(false, true);
+  ensureUndoState([[bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]], 0);
+
+  // Test moving items between folders.
+  let folder_b_info = createTestFolderInfo("Folder B");
+  let folder_b_txn = PT.NewFolder(folder_b_info);
+  folder_b_info.guid = await folder_b_txn.transact();
+  ensureUndoState(
+    [[folder_b_txn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+    0
+  );
+
+  moveTxn = PT.Move({
+    guid: bm_a_info.guid,
+    newParentGuid: folder_b_info.guid,
+    newIndex: bmsvc.DEFAULT_INDEX,
+  });
+  await moveTxn.transact();
+
+  ensureDo = () => {
+    ensureUndoState(
+      [[moveTxn], [folder_b_txn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+      0
+    );
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_a_info.guid,
+      newParentGuid: folder_b_info.guid,
+      oldIndex: 0,
+      newIndex: 0,
+    });
+    observer.reset();
+  };
+  ensureUndo = () => {
+    ensureUndoState(
+      [[moveTxn], [folder_b_txn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+      1
+    );
+    ensureItemsMoved({
+      guid: bm_a_info.guid,
+      oldParentGuid: folder_b_info.guid,
+      newParentGuid: folder_a_info.guid,
+      oldIndex: 0,
+      newIndex: 0,
+    });
+    observer.reset();
+  };
+
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+  await PT.redo();
+  ensureDo();
+  await PT.undo();
+  ensureUndo();
+
+  // Clean up
+  await PT.undo(); // folder_b_txn
+  await PT.undo(); // folder_a_txn + the bookmarks;
+  Assert.equal(observer.itemsRemoved.size, 5);
+  ensureUndoState(
+    [[moveTxn], [folder_b_txn], [bm_c_txn, bm_b_txn, bm_a_txn, folder_a_txn]],
+    3
+  );
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_remove_folder() {
+  let folder_level_1_info = createTestFolderInfo("Folder Level 1");
+  let folder_level_2_info = { title: "Folder Level 2" };
+
+  let folder_level_1_txn = PT.NewFolder(folder_level_1_info);
+  let folder_level_2_txn;
+  let results = await PT.batch([
+    folder_level_1_txn,
+    previousResults => {
+      folder_level_2_info.parentGuid = previousResults[0];
+      return (folder_level_2_txn = PT.NewFolder(folder_level_2_info));
+    },
+  ]);
+  folder_level_1_info.guid = results[0];
+  folder_level_2_info.guid = results[1];
+
+  let original_folder_level_1_tree = await PlacesUtils.promiseBookmarksTree(
+    folder_level_1_info.guid
+  );
+  let original_folder_level_2_tree = Object.assign(
+    { parentGuid: original_folder_level_1_tree.guid },
+    original_folder_level_1_tree.children[0]
+  );
+
+  ensureUndoState([[folder_level_2_txn, folder_level_1_txn]]);
+  await ensureItemsAdded(folder_level_1_info, folder_level_2_info);
+  observer.reset();
+
+  let remove_folder_2_txn = PT.Remove(folder_level_2_info);
+  await remove_folder_2_txn.transact();
+
+  ensureUndoState([
+    [remove_folder_2_txn],
+    [folder_level_2_txn, folder_level_1_txn],
+  ]);
+  await ensureItemsRemoved(folder_level_2_info);
+
+  // Undo Remove "Folder Level 2"
+  await PT.undo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    1
+  );
+  await ensureItemsAdded(folder_level_2_info);
+  await ensureBookmarksTreeRestoredCorrectly(original_folder_level_2_tree);
+  observer.reset();
+
+  // Redo Remove "Folder Level 2"
+  await PT.redo();
+  ensureUndoState([
+    [remove_folder_2_txn],
+    [folder_level_2_txn, folder_level_1_txn],
+  ]);
+  await ensureItemsRemoved(folder_level_2_info);
+  observer.reset();
+
+  // Undo it again
+  await PT.undo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    1
+  );
+  await ensureItemsAdded(folder_level_2_info);
+  await ensureBookmarksTreeRestoredCorrectly(original_folder_level_2_tree);
+  observer.reset();
+
+  // Undo the creation of both folders
+  await PT.undo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    2
+  );
+  await ensureItemsRemoved(folder_level_2_info, folder_level_1_info);
+  observer.reset();
+
+  // Redo the creation of both folders
+  await PT.redo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    1
+  );
+  await ensureItemsAdded(folder_level_1_info, folder_level_2_info);
+  await ensureBookmarksTreeRestoredCorrectlyExceptDates(
+    original_folder_level_1_tree
+  );
+  observer.reset();
+
+  // Redo Remove "Folder Level 2"
+  await PT.redo();
+  ensureUndoState([
+    [remove_folder_2_txn],
+    [folder_level_2_txn, folder_level_1_txn],
+  ]);
+  await ensureItemsRemoved(folder_level_2_info);
+  observer.reset();
+
+  // Undo everything one last time
+  await PT.undo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    1
+  );
+  await ensureItemsAdded(folder_level_2_info);
+  observer.reset();
+
+  await PT.undo();
+  ensureUndoState(
+    [[remove_folder_2_txn], [folder_level_2_txn, folder_level_1_txn]],
+    2
+  );
+  await ensureItemsRemoved(folder_level_2_info, folder_level_2_info);
+  observer.reset();
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_add_and_remove_bookmarks_with_additional_info() {
+  const testURI = "http://add.remove.tag";
+  const TAG_1 = "TestTag1";
+  const TAG_2 = "TestTag2";
+
+  let folder_info = createTestFolderInfo();
+  folder_info.guid = await PT.NewFolder(folder_info).transact();
+  let ensureTags = ensureTagsForURI.bind(null, testURI);
+
+  // Check that the NewBookmark transaction preserves tags.
+  observer.reset();
+  let b1_info = { parentGuid: folder_info.guid, url: testURI, tags: [TAG_1] };
+  b1_info.guid = await PT.NewBookmark(b1_info).transact();
+  let b1_originalInfo = await PlacesUtils.promiseBookmarksTree(b1_info.guid);
+  ensureTags([TAG_1]);
+  await PT.undo();
+  ensureTags([]);
+
+  observer.reset();
+  await PT.redo();
+  await ensureBookmarksTreeRestoredCorrectly(b1_originalInfo);
+  ensureTags([TAG_1]);
+
+  // Check if the Remove transaction removes and restores tags of children
+  // correctly.
+  await PT.Remove(folder_info.guid).transact();
+  ensureTags([]);
+
+  observer.reset();
+  await PT.undo();
+  await ensureBookmarksTreeRestoredCorrectly(b1_originalInfo);
+  ensureTags([TAG_1]);
+
+  await PT.redo();
+  ensureTags([]);
+
+  observer.reset();
+  await PT.undo();
+  await ensureBookmarksTreeRestoredCorrectly(b1_originalInfo);
+  ensureTags([TAG_1]);
+
+  // * Check that no-op tagging (the uri is already tagged with TAG_1) is
+  //   also a no-op on undo.
+  observer.reset();
+  let b2_info = {
+    parentGuid: folder_info.guid,
+    url: testURI,
+    tags: [TAG_1, TAG_2],
+  };
+  b2_info.guid = await PT.NewBookmark(b2_info).transact();
+  ensureTags([TAG_1, TAG_2]);
+
+  observer.reset();
+  await PT.undo();
+  await ensureItemsRemoved(b2_info);
+  ensureTags([TAG_1]);
+
+  // Check if Remove correctly restores tags.
+  observer.reset();
+  await PT.redo();
+  ensureTags([TAG_1, TAG_2]);
+
+  // Test Remove for multiple items.
+  observer.reset();
+  await PT.Remove(b1_info.guid).transact();
+  await PT.Remove(b2_info.guid).transact();
+  await PT.Remove(folder_info.guid).transact();
+  await ensureItemsRemoved(b1_info, b2_info, folder_info);
+  ensureTags([]);
+
+  observer.reset();
+  await PT.undo();
+  await ensureItemsAdded(folder_info);
+  ensureTags([]);
+
+  observer.reset();
+  await PT.undo();
+  ensureTags([TAG_1, TAG_2]);
+
+  observer.reset();
+  await PT.undo();
+  await ensureItemsAdded(b1_info);
+  ensureTags([TAG_1, TAG_2]);
+
+  // The redo calls below cleanup everything we did.
+  observer.reset();
+  await PT.redo();
+  await ensureItemsRemoved(b1_info);
+  ensureTags([TAG_1, TAG_2]);
+
+  observer.reset();
+  await PT.redo();
+  // The tag containers are removed in async and take some time
+  let oldCountTag1 = 0;
+  let oldCountTag2 = 0;
+  let allTags = await bmsvc.fetchTags();
+  for (let i of allTags) {
+    if (i.name == TAG_1) {
+      oldCountTag1 = i.count;
+    }
+    if (i.name == TAG_2) {
+      oldCountTag2 = i.count;
+    }
+  }
+  await TestUtils.waitForCondition(async () => {
+    allTags = await bmsvc.fetchTags();
+    let newCountTag1 = 0;
+    let newCountTag2 = 0;
+    for (let i of allTags) {
+      if (i.name == TAG_1) {
+        newCountTag1 = i.count;
+      }
+      if (i.name == TAG_2) {
+        newCountTag2 = i.count;
+      }
+    }
+    return newCountTag1 == oldCountTag1 - 1 && newCountTag2 == oldCountTag2 - 1;
+  });
+  await ensureItemsRemoved(b2_info);
+
+  ensureTags([]);
+
+  observer.reset();
+  await PT.redo();
+  await ensureItemsRemoved(folder_info);
+  ensureTags([]);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_creating_and_removing_a_separator() {
+  let folder_info = createTestFolderInfo();
+  let separator_info = {};
+  let undoEntries = [];
+
+  observer.reset();
+  let folder_txn = PT.NewFolder(folder_info);
+  let separator_txn;
+  let results = await PT.batch([
+    folder_txn,
+    previousResults => {
+      separator_info.parentGuid = previousResults[0];
+      return (separator_txn = PT.NewSeparator(separator_info));
+    },
+  ]);
+  folder_info.guid = results[0];
+  separator_info.guid = results[1];
+
+  undoEntries.unshift([separator_txn, folder_txn]);
+  ensureUndoState(undoEntries, 0);
+  ensureItemsAdded(folder_info, separator_info);
+
+  observer.reset();
+  await PT.undo();
+  ensureUndoState(undoEntries, 1);
+  ensureItemsRemoved(folder_info, separator_info);
+
+  observer.reset();
+  await PT.redo();
+  ensureUndoState(undoEntries, 0);
+  ensureItemsAdded(folder_info, separator_info);
+
+  observer.reset();
+  let remove_sep_txn = PT.Remove(separator_info);
+  await remove_sep_txn.transact();
+  undoEntries.unshift([remove_sep_txn]);
+  ensureUndoState(undoEntries, 0);
+  ensureItemsRemoved(separator_info);
+
+  observer.reset();
+  await PT.undo();
+  ensureUndoState(undoEntries, 1);
+  ensureItemsAdded(separator_info);
+
+  observer.reset();
+  await PT.undo();
+  ensureUndoState(undoEntries, 2);
+  ensureItemsRemoved(folder_info, separator_info);
+
+  observer.reset();
+  await PT.redo();
+  ensureUndoState(undoEntries, 1);
+  ensureItemsAdded(folder_info, separator_info);
+
+  // Clear redo entries and check that |redo| does nothing
+  observer.reset();
+  await PT.clearTransactionsHistory(false, true);
+  undoEntries.shift();
+  ensureUndoState(undoEntries, 0);
+  await PT.redo();
+  ensureItemsAdded();
+  ensureItemsRemoved();
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureUndoState(undoEntries, 1);
+  ensureItemsRemoved(folder_info, separator_info);
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_edit_title() {
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test_create_item.com",
+    title: "Original Title",
+  };
+
+  function ensureTitleChange(aCurrentTitle) {
+    ensureItemsTitleChanged({
+      guid: bm_info.guid,
+      title: aCurrentTitle,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+  }
+
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+
+  observer.reset();
+  await PT.EditTitle({ guid: bm_info.guid, title: "New Title" }).transact();
+  ensureTitleChange("New Title");
+
+  observer.reset();
+  await PT.undo();
+  ensureTitleChange("Original Title");
+
+  observer.reset();
+  await PT.redo();
+  ensureTitleChange("New Title");
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureTitleChange("Original Title");
+  await PT.undo();
+  ensureItemsRemoved(bm_info);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_edit_url() {
+  let oldURI = "http://old.test_editing_item_uri.com/";
+  let newURI = "http://new.test_editing_item_uri.com/";
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: oldURI,
+    tags: ["TestTag"],
+  };
+  function ensureURIAndTags(
+    aPreChangeURI,
+    aPostChangeURI,
+    aOLdURITagsPreserved
+  ) {
+    ensureItemsUrlChanged({
+      guid: bm_info.guid,
+      url: aPostChangeURI,
+    });
+    ensureTagsForURI(aPostChangeURI, bm_info.tags);
+    ensureTagsForURI(aPreChangeURI, aOLdURITagsPreserved ? bm_info.tags : []);
+  }
+
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+  ensureTagsForURI(oldURI, bm_info.tags);
+
+  // When there's a single bookmark for the same url, tags should be moved.
+  observer.reset();
+  await PT.EditUrl({ guid: bm_info.guid, url: newURI }).transact();
+  ensureURIAndTags(oldURI, newURI, false);
+
+  observer.reset();
+  await PT.undo();
+  ensureURIAndTags(newURI, oldURI, false);
+
+  observer.reset();
+  await PT.redo();
+  ensureURIAndTags(oldURI, newURI, false);
+
+  observer.reset();
+  await PT.undo();
+  ensureURIAndTags(newURI, oldURI, false);
+
+  // When there're multiple bookmarks for the same url, tags should be copied.
+  let bm2_info = Object.create(bm_info);
+  bm2_info.guid = await PT.NewBookmark(bm2_info).transact();
+  let bm3_info = Object.create(bm_info);
+  bm3_info.url = newURI;
+  bm3_info.guid = await PT.NewBookmark(bm3_info).transact();
+
+  observer.reset();
+  await PT.EditUrl({ guid: bm_info.guid, url: newURI }).transact();
+  ensureURIAndTags(oldURI, newURI, true);
+
+  observer.reset();
+  await PT.undo();
+  ensureURIAndTags(newURI, oldURI, true);
+
+  observer.reset();
+  await PT.redo();
+  ensureURIAndTags(oldURI, newURI, true);
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureURIAndTags(newURI, oldURI, true);
+  await PT.undo();
+  await PT.undo();
+  await PT.undo();
+  ensureItemsRemoved(bm3_info, bm2_info, bm_info);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_edit_keyword() {
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test.edit.keyword/",
+  };
+  const KEYWORD = "test_keyword";
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+  function ensureKeywordChange(aCurrentKeyword = "") {
+    ensureItemsKeywordChanged({
+      guid: bm_info.guid,
+      keyword: aCurrentKeyword,
+    });
+  }
+
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+
+  observer.reset();
+  await PT.EditKeyword({
+    guid: bm_info.guid,
+    keyword: KEYWORD,
+    postData: "postData",
+  }).transact();
+  ensureKeywordChange(KEYWORD);
+  let entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData");
+
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange();
+  entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry, null);
+
+  observer.reset();
+  await PT.redo();
+  ensureKeywordChange(KEYWORD);
+  entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData");
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange();
+  await PT.undo();
+  ensureItemsRemoved(bm_info);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_edit_keyword_null_postData() {
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test.edit.keyword/",
+  };
+  const KEYWORD = "test_keyword";
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+  function ensureKeywordChange(aCurrentKeyword = "") {
+    ensureItemsKeywordChanged({
+      guid: bm_info.guid,
+      keyword: aCurrentKeyword,
+    });
+  }
+
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+
+  observer.reset();
+  await PT.EditKeyword({
+    guid: bm_info.guid,
+    keyword: KEYWORD,
+    postData: null,
+  }).transact();
+  ensureKeywordChange(KEYWORD);
+  let entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, null);
+
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange();
+  entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry, null);
+
+  observer.reset();
+  await PT.redo();
+  ensureKeywordChange(KEYWORD);
+  entry = await PlacesUtils.keywords.fetch(KEYWORD);
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, null);
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange();
+  await PT.undo();
+  ensureItemsRemoved(bm_info);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_edit_specific_keyword() {
+  let bm_info = {
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test.edit.keyword/",
+  };
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+  function ensureKeywordChange(aCurrentKeyword = "", aPreviousKeyword = "") {
+    ensureItemsKeywordChanged({
+      guid: bm_info.guid,
+      keyword: aCurrentKeyword,
+    });
+  }
+
+  await PlacesUtils.keywords.insert({
+    keyword: "kw1",
+    url: bm_info.url,
+    postData: "postData1",
+  });
+  await PlacesUtils.keywords.insert({
+    keyword: "kw2",
+    url: bm_info.url,
+    postData: "postData2",
+  });
+  bm_info.guid = await PT.NewBookmark(bm_info).transact();
+
+  observer.reset();
+  await PT.EditKeyword({
+    guid: bm_info.guid,
+    keyword: "keyword",
+    oldKeyword: "kw2",
+  }).transact();
+  ensureKeywordChange("keyword", "kw2");
+  let entry = await PlacesUtils.keywords.fetch("kw1");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData1");
+  entry = await PlacesUtils.keywords.fetch("keyword");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData2");
+  entry = await PlacesUtils.keywords.fetch("kw2");
+  Assert.equal(entry, null);
+
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange("kw2", "keyword");
+  entry = await PlacesUtils.keywords.fetch("kw1");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData1");
+  entry = await PlacesUtils.keywords.fetch("kw2");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData2");
+  entry = await PlacesUtils.keywords.fetch("keyword");
+  Assert.equal(entry, null);
+
+  observer.reset();
+  await PT.redo();
+  ensureKeywordChange("keyword", "kw2");
+  entry = await PlacesUtils.keywords.fetch("kw1");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData1");
+  entry = await PlacesUtils.keywords.fetch("keyword");
+  Assert.equal(entry.url.href, bm_info.url);
+  Assert.equal(entry.postData, "postData2");
+  entry = await PlacesUtils.keywords.fetch("kw2");
+  Assert.equal(entry, null);
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureKeywordChange("kw2");
+  await PT.undo();
+  ensureItemsRemoved(bm_info);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_tag_uri() {
+  // This also tests passing uri specs.
+  let bm_info_a = {
+    url: "http://bookmarked.uri",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  let bm_info_b = {
+    url: "http://bookmarked2.uri",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  };
+  let unbookmarked_uri = "http://un.bookmarked.uri";
+
+  let results = await PT.batch([
+    PT.NewBookmark(bm_info_a),
+    PT.NewBookmark(bm_info_b),
+  ]);
+  bm_info_a.guid = results[0];
+  bm_info_b.guid = results[1];
+
+  async function doTest(aInfo) {
+    let urls = "url" in aInfo ? [aInfo.url] : aInfo.urls;
+    let tags = "tag" in aInfo ? [aInfo.tag] : aInfo.tags;
+
+    let tagWillAlsoBookmark = new Set();
+    for (let url of urls) {
+      if (!(await bmsvc.fetch({ url }))) {
+        tagWillAlsoBookmark.add(url);
+      }
+    }
+
+    async function ensureTagsSet() {
+      for (let url of urls) {
+        ensureTagsForURI(url, tags);
+        Assert.ok(await bmsvc.fetch({ url }));
+      }
+    }
+    async function ensureTagsUnset() {
+      for (let url of urls) {
+        ensureTagsForURI(url, []);
+        if (tagWillAlsoBookmark.has(url)) {
+          Assert.ok(!(await bmsvc.fetch({ url })));
+        } else {
+          Assert.ok(await bmsvc.fetch({ url }));
+        }
+      }
+    }
+
+    await PT.Tag(aInfo).transact();
+    await ensureTagsSet();
+    await PT.undo();
+    await ensureTagsUnset();
+    await PT.redo();
+    await ensureTagsSet();
+    await PT.undo();
+    await ensureTagsUnset();
+  }
+
+  await doTest({ url: bm_info_a.url, tags: ["MyTag"] });
+  await doTest({ urls: [bm_info_a.url], tag: "MyTag" });
+  await doTest({ urls: [bm_info_a.url, bm_info_b.url], tags: ["A, B"] });
+  await doTest({ urls: [bm_info_a.url, unbookmarked_uri], tag: "C" });
+  // Duplicate URLs listed.
+  await doTest({
+    urls: [bm_info_a.url, bm_info_b.url, bm_info_a.url],
+    tag: "D",
+  });
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureItemsRemoved(bm_info_a, bm_info_b);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_untag_uri() {
+  let bm_info_a = {
+    url: "http://bookmarked.uri",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    tags: ["A", "B"],
+  };
+  let bm_info_b = {
+    url: "http://bookmarked2.uri",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    tag: "B",
+  };
+
+  let results = await PT.batch([
+    PT.NewBookmark(bm_info_a),
+    PT.NewBookmark(bm_info_b),
+  ]);
+  ensureTagsForURI(bm_info_a.url, bm_info_a.tags);
+  ensureTagsForURI(bm_info_b.url, [bm_info_b.tag]);
+  bm_info_a.guid = results[0];
+
+  bm_info_b.guid = results[1];
+
+  async function doTest(aInfo) {
+    let urls, tagsRemoved;
+    if (typeof aInfo == "string") {
+      urls = [aInfo];
+      tagsRemoved = [];
+    } else if (Array.isArray(aInfo)) {
+      urls = aInfo;
+      tagsRemoved = [];
+    } else {
+      urls = "url" in aInfo ? [aInfo.url] : aInfo.urls;
+      tagsRemoved = "tag" in aInfo ? [aInfo.tag] : aInfo.tags;
+    }
+
+    let preRemovalTags = new Map();
+    for (let url of urls) {
+      preRemovalTags.set(url, tagssvc.getTagsForURI(Services.io.newURI(url)));
+    }
+
+    function ensureTagsSet() {
+      for (let url of urls) {
+        ensureTagsForURI(url, preRemovalTags.get(url));
+      }
+    }
+    function ensureTagsUnset() {
+      for (let url of urls) {
+        let expectedTags = !tagsRemoved.length
+          ? []
+          : preRemovalTags.get(url).filter(tag => !tagsRemoved.includes(tag));
+        ensureTagsForURI(url, expectedTags);
+      }
+    }
+
+    await PT.Untag(aInfo).transact();
+    await ensureTagsUnset();
+    await PT.undo();
+    await ensureTagsSet();
+    await PT.redo();
+    await ensureTagsUnset();
+    await PT.undo();
+    await ensureTagsSet();
+  }
+
+  await doTest(bm_info_a);
+  await doTest(bm_info_b);
+  await doTest(bm_info_a.url);
+  await doTest(bm_info_b.url);
+  await doTest([bm_info_a.url, bm_info_b.url]);
+  await doTest({ urls: [bm_info_a.url, bm_info_b.url], tags: ["A", "B"] });
+  await doTest({ urls: [bm_info_a.url, bm_info_b.url], tag: "B" });
+  await doTest({ urls: [bm_info_a.url, bm_info_b.url], tag: "C" });
+  await doTest({ urls: [bm_info_a.url, bm_info_b.url], tags: ["C"] });
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureItemsRemoved(bm_info_a, bm_info_b);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+});
+
+add_task(async function test_sort_folder_by_name() {
+  let folder_info = createTestFolderInfo();
+
+  let url = "http://sort.by.name/";
+  let preSep = ["3", "2", "1"].map(i => ({ title: i, url }));
+  let sep = {};
+  let postSep = ["c", "b", "a"].map(l => ({ title: l, url }));
+  let originalOrder = [...preSep, sep, ...postSep];
+  let sortedOrder = [
+    ...preSep.slice(0).reverse(),
+    sep,
+    ...postSep.slice(0).reverse(),
+  ];
+
+  let folder_txn = await PT.NewFolder(folder_info);
+  let transactions = [folder_txn];
+  for (let info of originalOrder) {
+    transactions.push(previousResults => {
+      info.parentGuid = previousResults[0];
+      return info == sep ? PT.NewSeparator(info) : PT.NewBookmark(info);
+    });
+  }
+  let results = await PT.batch(transactions);
+  folder_info.guid = results[0];
+  for (let i = 0; i < originalOrder.length; ++i) {
+    originalOrder[i].guid = results[i + 1];
+  }
+
+  let folderContainer = PlacesUtils.getFolderContents(folder_info.guid).root;
+  function ensureOrder(aOrder) {
+    for (let i = 0; i < folderContainer.childCount; i++) {
+      Assert.equal(folderContainer.getChild(i).bookmarkGuid, aOrder[i].guid);
+    }
+  }
+
+  ensureOrder(originalOrder);
+  await PT.SortByName(folder_info.guid).transact();
+  ensureOrder(sortedOrder);
+  await PT.undo();
+  ensureOrder(originalOrder);
+  await PT.redo();
+  ensureOrder(sortedOrder);
+
+  // Cleanup
+  observer.reset();
+  await PT.undo();
+  ensureOrder(originalOrder);
+  await PT.undo();
+  ensureItemsRemoved(...originalOrder, folder_info);
+});
+
+add_task(async function test_copy() {
+  async function duplicate_and_test(aOriginalGuid) {
+    let txn = PT.Copy({
+      guid: aOriginalGuid,
+      newParentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+    let duplicateGuid = await txn.transact();
+    let originalInfo = await PlacesUtils.promiseBookmarksTree(aOriginalGuid);
+    let duplicateInfo = await PlacesUtils.promiseBookmarksTree(duplicateGuid);
+    await ensureEqualBookmarksTrees(originalInfo, duplicateInfo, false);
+
+    async function redo() {
+      await PT.redo();
+      await ensureBookmarksTreeRestoredCorrectlyExceptDates(originalInfo);
+      await PT.redo();
+      await ensureBookmarksTreeRestoredCorrectlyExceptDates(duplicateInfo);
+    }
+    async function undo() {
+      await PT.undo();
+      // also undo the original item addition.
+      await PT.undo();
+      await ensureNonExistent(aOriginalGuid, duplicateGuid);
+    }
+
+    await undo();
+    await redo();
+    await undo();
+    await redo();
+
+    // Cleanup. This also remove the original item.
+    await PT.undo();
+    observer.reset();
+    await PT.clearTransactionsHistory();
+  }
+
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  // Test duplicating leafs (bookmark, separator, empty folder)
+  PT.NewBookmark({
+    url: "http://test.item.duplicate",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    annos: [{ name: "Anno", value: "AnnoValue" }],
+  });
+  let sepTxn = PT.NewSeparator({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: 1,
+  });
+
+  let emptyFolderTxn = PT.NewFolder(createTestFolderInfo());
+  for (let txn of [sepTxn, emptyFolderTxn]) {
+    let guid = await txn.transact();
+    await duplicate_and_test(guid);
+  }
+
+  // Test duplicating a folder having some contents.
+  let results = await PT.batch([
+    PT.NewFolder(createTestFolderInfo()),
+    previousResults =>
+      PT.NewFolder({
+        parentGuid: previousResults[0],
+        title: "Nested Folder",
+      }),
+    // Insert a bookmark under the nested folder.
+    previousResults =>
+      PT.NewBookmark({
+        url: "http://nested.nested.bookmark",
+        parentGuid: previousResults[1],
+      }),
+    // Insert a separator below the nested folder
+    previousResults => PT.NewSeparator({ parentGuid: previousResults[0] }),
+    // And another bookmark.
+    previousResults =>
+      PT.NewBookmark({
+        url: "http://nested.bookmark",
+        parentGuid: previousResults[0],
+      }),
+  ]);
+  let filledFolderGuid = results[0];
+
+  await duplicate_and_test(filledFolderGuid);
+
+  // Cleanup
+  await PT.clearTransactionsHistory();
+});
+
+add_task(async function test_array_input_for_batch() {
+  let folderTxn = PT.NewFolder(createTestFolderInfo());
+  let folderGuid = await folderTxn.transact();
+
+  let sep1_txn = PT.NewSeparator({ parentGuid: folderGuid });
+  let sep2_txn = PT.NewSeparator({ parentGuid: folderGuid });
+  await PT.batch([sep1_txn, sep2_txn]);
+  ensureUndoState([[sep2_txn, sep1_txn], [folderTxn]], 0);
+
+  let ensureChildCount = async function (count) {
+    let tree = await PlacesUtils.promiseBookmarksTree(folderGuid);
+    if (count == 0) {
+      Assert.ok(!("children" in tree));
+    } else {
+      Assert.equal(tree.children.length, count);
+    }
+  };
+
+  await ensureChildCount(2);
+  await PT.undo();
+  await ensureChildCount(0);
+  await PT.redo();
+  await ensureChildCount(2);
+  await PT.undo();
+  await ensureChildCount(0);
+
+  await PT.undo();
+  Assert.equal(await PlacesUtils.promiseBookmarksTree(folderGuid), null);
+
+  // Cleanup
+  await PT.clearTransactionsHistory();
+});
+
+add_task(async function test_invalid_uri_spec_throws() {
+  Assert.throws(
+    () =>
+      PT.NewBookmark({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: "invalid uri spec",
+        title: "test bookmark",
+      }),
+    /invalid uri spec is not a valid URL/
+  );
+  Assert.throws(
+    () => PT.Tag({ tag: "TheTag", urls: ["invalid uri spec"] }),
+    /TypeError: URL constructor: invalid uri spec is not a valid URL/
+  );
+  Assert.throws(
+    () => PT.Tag({ tag: "TheTag", urls: ["about:blank", "invalid uri spec"] }),
+    /TypeError: URL constructor: invalid uri spec is not a valid URL/
+  );
+});
+
+add_task(async function test_remove_multiple() {
+  let results = await PT.batch([
+    PT.NewFolder({
+      title: "Test Folder",
+      parentGuid: menuGuid,
+    }),
+    previousResults =>
+      PT.NewFolder({
+        title: "Nested Test Folder",
+        parentGuid: previousResults[0],
+      }),
+    previousResults => PT.NewSeparator(previousResults[1]),
+    PT.NewBookmark({
+      url: "http://test.bookmark.removed",
+      parentGuid: menuGuid,
+    }),
+  ]);
+  let guids = [results[0], results[3]];
+
+  let originalInfos = [];
+  for (let guid of guids) {
+    originalInfos.push(await PlacesUtils.promiseBookmarksTree(guid));
+  }
+
+  await PT.Remove(guids).transact();
+  await ensureNonExistent(...guids);
+  await PT.undo();
+  await ensureBookmarksTreeRestoredCorrectly(...originalInfos);
+  await PT.redo();
+  await ensureNonExistent(...guids);
+  await PT.undo();
+  await ensureBookmarksTreeRestoredCorrectly(...originalInfos);
+
+  // Undo the New* transactions batch.
+  await PT.undo();
+  await ensureNonExistent(...guids);
+
+  // Redo it.
+  await PT.redo();
+  await ensureBookmarksTreeRestoredCorrectlyExceptDates(...originalInfos);
+
+  // Redo remove.
+  await PT.redo();
+  await ensureNonExistent(...guids);
+
+  // Cleanup
+  await PT.clearTransactionsHistory();
+  observer.reset();
+});
+
+add_task(async function test_renameTag() {
+  let url = "http://test.edit.keyword/";
+  await PT.Tag({ url, tags: ["t1", "t2"] }).transact();
+  ensureTagsForURI(url, ["t1", "t2"]);
+
+  // Create bookmark queries that point to the modified tag.
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    url: "place:tag=t2",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let bm2 = await PlacesUtils.bookmarks.insert({
+    url: "place:tag=t2&sort=1",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  // This points to 2 tags, and as such won't be touched.
+  let bm3 = await PlacesUtils.bookmarks.insert({
+    url: "place:tag=t2&tag=t1",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+
+  await PT.RenameTag({ oldTag: "t2", tag: "t3" }).transact();
+  ensureTagsForURI(url, ["t1", "t3"]);
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm1.guid)).url.href,
+    "place:tag=t3",
+    "The fitst bookmark has been updated"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm2.guid)).url.href,
+    "place:tag=t3&sort=1",
+    "The second bookmark has been updated"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm3.guid)).url.href,
+    "place:tag=t3&tag=t1",
+    "The third bookmark has been updated"
+  );
+
+  await PT.undo();
+  ensureTagsForURI(url, ["t1", "t2"]);
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm1.guid)).url.href,
+    "place:tag=t2",
+    "The fitst bookmark has been restored"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm2.guid)).url.href,
+    "place:tag=t2&sort=1",
+    "The second bookmark has been restored"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm3.guid)).url.href,
+    "place:tag=t2&tag=t1",
+    "The third bookmark has been restored"
+  );
+
+  await PT.redo();
+  ensureTagsForURI(url, ["t1", "t3"]);
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm1.guid)).url.href,
+    "place:tag=t3",
+    "The fitst bookmark has been updated"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm2.guid)).url.href,
+    "place:tag=t3&sort=1",
+    "The second bookmark has been updated"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm3.guid)).url.href,
+    "place:tag=t3&tag=t1",
+    "The third bookmark has been updated"
+  );
+
+  await PT.undo();
+  ensureTagsForURI(url, ["t1", "t2"]);
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm1.guid)).url.href,
+    "place:tag=t2",
+    "The fitst bookmark has been restored"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm2.guid)).url.href,
+    "place:tag=t2&sort=1",
+    "The second bookmark has been restored"
+  );
+  Assert.equal(
+    (await PlacesUtils.bookmarks.fetch(bm3.guid)).url.href,
+    "place:tag=t2&tag=t1",
+    "The third bookmark has been restored"
+  );
+
+  await PT.undo();
+  ensureTagsForURI(url, []);
+
+  await PT.clearTransactionsHistory();
+  ensureUndoState();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_remove_invalid_url() {
+  let folderGuid = await PT.NewFolder({
+    title: "Test Folder",
+    parentGuid: menuGuid,
+  }).transact();
+
+  let guid = "invalid_____";
+  let folderedGuid = "invalid____2";
+  let url = "invalid-uri";
+  await PlacesUtils.withConnectionWrapper("test_bookmarks_remove", async db => {
+    await db.execute(
+      `
+      INSERT INTO moz_places(url, url_hash, title, rev_host, guid)
+      VALUES (:url, hash(:url), 'Invalid URI', '.', GENERATE_GUID())
+    `,
+      { url }
+    );
+    await db.execute(
+      `INSERT INTO moz_bookmarks (type, fk, parent, position, guid)
+        VALUES (:type,
+                (SELECT id FROM moz_places WHERE url = :url),
+                (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+                (SELECT MAX(position) + 1 FROM moz_bookmarks WHERE parent = (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid)),
+                :guid)
+      `,
+      {
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        guid,
+      }
+    );
+    await db.execute(
+      `INSERT INTO moz_bookmarks (type, fk, parent, position, guid)
+        VALUES (:type,
+                (SELECT id FROM moz_places WHERE url = :url),
+                (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid),
+                (SELECT MAX(position) + 1 FROM moz_bookmarks WHERE parent = (SELECT id FROM moz_bookmarks WHERE guid = :parentGuid)),
+                :guid)
+      `,
+      {
+        type: PlacesUtils.bookmarks.TYPE_BOOKMARK,
+        url,
+        parentGuid: folderGuid,
+        guid: folderedGuid,
+      }
+    );
+  });
+
+  let guids = [folderGuid, guid];
+  await PT.Remove(guids).transact();
+  await ensureNonExistent(...guids, folderedGuid);
+  // Shouldn't throw, should restore the folder but not the bookmarks.
+  await PT.undo();
+  await ensureNonExistent(guid, folderedGuid);
+  Assert.ok(
+    await PlacesUtils.bookmarks.fetch(folderGuid),
+    "The folder should have been re-created"
+  );
+  await PT.redo();
+  await ensureNonExistent(guids, folderedGuid);
+  // Cleanup
+  await PT.clearTransactionsHistory();
+  observer.reset();
+});
diff --git a/toolkit/components/places/tests/unit/test_autocomplete_match_fallbackTitle.js b/toolkit/components/places/tests/unit/test_autocomplete_match_fallbackTitle.js
new file mode 100644
index 0000000000..109ca1edce
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_autocomplete_match_fallbackTitle.js
@@ -0,0 +1,27 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This is a test for the fallbackTitle argument of autocomplete_match.
+
+add_task(async function test_match() {
+  async function search(text) {
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(
+      `
+      SELECT AUTOCOMPLETE_MATCH(:text, 'http://mozilla.org/', 'Main title',
+                                NULL, NULL, 1, 1, NULL,
+                                :matchBehavior, :searchBehavior,
+                                'Fallback title')
+      `,
+      {
+        text,
+        matchBehavior: Ci.mozIPlacesAutoComplete.MATCH_ANYWHERE,
+        searchBehavior: 643,
+      }
+    );
+    return !!rows[0].getResultByIndex(0);
+  }
+  Assert.ok(await search("mai"), "Match on main title");
+  Assert.ok(await search("fall"), "Match on fallback title");
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmark-tags-changed_frequency.js b/toolkit/components/places/tests/unit/test_bookmark-tags-changed_frequency.js
new file mode 100644
index 0000000000..d7f0cf21c8
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmark-tags-changed_frequency.js
@@ -0,0 +1,56 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test checks that changing a tag for a bookmark with multiple tags
+// notifies bookmark-tags-changed event only once, and not once per tag.
+
+add_task(async function run_test() {
+  let tags = ["a", "b", "c"];
+  let uri = Services.io.newURI("http://1.moz.org/");
+
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: uri,
+    title: "Bookmark 1",
+  });
+  PlacesUtils.tagging.tagURI(uri, tags);
+
+  let promise = Promise.withResolvers();
+
+  let bookmarksObserver = {
+    _changedCount: 0,
+    handlePlacesEvents(events) {
+      for (let event of events) {
+        switch (event.type) {
+          case "bookmark-removed":
+            if (event.guid == bookmark.guid) {
+              PlacesUtils.observers.removeListener(
+                ["bookmark-removed"],
+                this.handlePlacesEvents
+              );
+              Assert.equal(this._changedCount, 2);
+              promise.resolve();
+            }
+            break;
+          case "bookmark-tags-changed":
+            Assert.equal(event.guid, bookmark.guid);
+            this._changedCount++;
+            break;
+        }
+      }
+    },
+  };
+  bookmarksObserver.handlePlacesEvents =
+    bookmarksObserver.handlePlacesEvents.bind(bookmarksObserver);
+  PlacesUtils.observers.addListener(
+    ["bookmark-removed", "bookmark-tags-changed"],
+    bookmarksObserver.handlePlacesEvents
+  );
+
+  PlacesUtils.tagging.tagURI(uri, ["d"]);
+  PlacesUtils.tagging.tagURI(uri, ["e"]);
+
+  await promise;
+
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html.js b/toolkit/components/places/tests/unit/test_bookmarks_html.js
new file mode 100644
index 0000000000..4b3f04b444
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html.js
@@ -0,0 +1,417 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// An object representing the contents of bookmarks.preplaces.html.
+var test_bookmarks = {
+  menu: [
+    {
+      title: "Mozilla Firefox",
+      children: [
+        {
+          title: "Help and Tutorials",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/help/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          title: "Customize Firefox",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/customize/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          title: "Get Involved",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/community/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          title: "About Us",
+          url: "http://en-us.www.mozilla.com/en-US/about/",
+          icon: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg==",
+        },
+      ],
+    },
+    {
+      type: Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR,
+    },
+    {
+      title: "test",
+      dateAdded: 1177541020000000,
+      lastModified: 1177541050000000,
+      children: [
+        {
+          title: "test post keyword",
+          dateAdded: 1177375336000000,
+          lastModified: 1177375423000000,
+          keyword: "test",
+          postData: "hidden1%3Dbar&text1%3D%25s",
+          charset: "ISO-8859-1",
+          url: "http://test/post",
+        },
+      ],
+    },
+  ],
+  toolbar: [
+    {
+      title: "Getting Started",
+      url: "http://en-us.www.mozilla.com/en-US/firefox/central/",
+      icon: "data:image/png;base64,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",
+    },
+    {
+      title: "Latest Headlines",
+      url: "http://en-us.fxfeeds.mozilla.com/en-US/firefox/livebookmarks/",
+      feedUrl: "http://en-us.fxfeeds.mozilla.com/en-US/firefox/headlines.xml",
+    },
+    // This will be ignored, because it has no url.
+    {
+      title: "Latest Headlines No Site",
+      feedUrl: "http://en-us.fxfeeds.mozilla.com/en-US/firefox/headlines.xml",
+      ignore: true,
+    },
+  ],
+  unfiled: [{ title: "Example.tld", url: "http://example.tld/" }],
+};
+
+// Pre-Places bookmarks.html file pointer.
+var gBookmarksFileOld;
+// Places bookmarks.html file pointer.
+var gBookmarksFileNew;
+
+add_task(async function setup() {
+  // File pointer to legacy bookmarks file.
+  gBookmarksFileOld = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks.preplaces.html"
+  );
+
+  // File pointer to a new Places-exported bookmarks file.
+  gBookmarksFileNew = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.html"
+  );
+  await IOUtils.remove(gBookmarksFileNew, { ignoreAbsent: true });
+
+  // This test must be the first one, since it setups the new bookmarks.html.
+  // Test importing a pre-Places canonical bookmarks file.
+  // 1. import bookmarks.preplaces.html
+  // 2. run the test-suite
+  // Note: we do not empty the db before this import to catch bugs like 380999
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileOld, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_count() {
+  // Ensure the bookmarks count is correct when importing in various cases
+  let count = await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, {
+    replace: true,
+  });
+  Assert.equal(
+    count,
+    8,
+    "There should be 8 imported bookmarks when importing from an empty database"
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  count = -1;
+  count = await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, {
+    replace: true,
+  });
+  Assert.equal(
+    count,
+    8,
+    "There should be 8 imported bookmarks when replacing existing bookmarks"
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  count = -1;
+  count = await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew);
+  Assert.equal(
+    count,
+    8,
+    "There should be 8 imported bookmarks even when we are not replacing existing bookmarks"
+  );
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_new() {
+  // Test importing a Places bookmarks.html file.
+  // 1. import bookmarks.exported.html
+  // 2. run the test-suite
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  await testImportedBookmarks();
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_emptytitle_export() {
+  // Test exporting and importing with an empty-titled bookmark.
+  // 1. import bookmarks
+  // 2. create an empty-titled bookmark.
+  // 3. export to bookmarks.exported.html
+  // 4. empty bookmarks db
+  // 5. import bookmarks.exported.html
+  // 6. run the test-suite
+  // 7. remove the empty-titled bookmark
+  // 8. export to bookmarks.exported.html
+  // 9. empty bookmarks db and continue
+
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  const NOTITLE_URL = "http://notitle.mozilla.org/";
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: NOTITLE_URL,
+  });
+  test_bookmarks.unfiled.push({ title: "", url: NOTITLE_URL });
+
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+
+  // Cleanup.
+  test_bookmarks.unfiled.pop();
+  // HTML imports don't restore GUIDs yet.
+  let reimportedBookmark = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  Assert.equal(reimportedBookmark.url.href, bookmark.url.href);
+  await PlacesUtils.bookmarks.remove(reimportedBookmark);
+
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_chromefavicon() {
+  // Test exporting and importing with a bookmark pointing to a chrome favicon.
+  // 1. import bookmarks
+  // 2. create a bookmark pointing to a chrome favicon.
+  // 3. export to bookmarks.exported.html
+  // 4. empty bookmarks db
+  // 5. import bookmarks.exported.html
+  // 6. run the test-suite
+  // 7. remove the bookmark pointing to a chrome favicon.
+  // 8. export to bookmarks.exported.html
+  // 9. empty bookmarks db and continue
+
+  const PAGE_URI = NetUtil.newURI("http://example.com/chromefavicon_page");
+  const CHROME_FAVICON_URI = NetUtil.newURI(
+    "chrome://global/skin/icons/delete.svg"
+  );
+  const CHROME_FAVICON_URI_2 = NetUtil.newURI(
+    "chrome://global/skin/icons/error.svg"
+  );
+
+  info("Importing from html");
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  info("Insert bookmark");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: PAGE_URI,
+    title: "Test",
+  });
+
+  info("Set favicon");
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      PAGE_URI,
+      CHROME_FAVICON_URI,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      resolve,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  let data = await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      PAGE_URI,
+      (uri, dataLen, faviconData, mimeType) => resolve(faviconData)
+    );
+  });
+
+  let base64Icon =
+    "data:image/png;base64," +
+    base64EncodeString(String.fromCharCode.apply(String, data));
+
+  test_bookmarks.unfiled.push({
+    title: "Test",
+    url: PAGE_URI.spec,
+    icon: base64Icon,
+  });
+
+  info("Export to html");
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  info("Set favicon");
+  // Change the favicon to check it's really imported again later.
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setAndFetchFaviconForPage(
+      PAGE_URI,
+      CHROME_FAVICON_URI_2,
+      true,
+      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+      resolve,
+      Services.scriptSecurityManager.getSystemPrincipal()
+    );
+  });
+
+  info("import from html");
+  await PlacesUtils.bookmarks.eraseEverything();
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  info("Test imported bookmarks");
+  await testImportedBookmarks();
+
+  // Cleanup.
+  test_bookmarks.unfiled.pop();
+  // HTML imports don't restore GUIDs yet.
+  let reimportedBookmark = await PlacesUtils.bookmarks.fetch({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    index: PlacesUtils.bookmarks.DEFAULT_INDEX,
+  });
+  await PlacesUtils.bookmarks.remove(reimportedBookmark);
+
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_ontop() {
+  // Test importing the exported bookmarks.html file *on top of* the existing
+  // bookmarks.
+  // 1. empty bookmarks db
+  // 2. import the exported bookmarks file
+  // 3. export to file
+  // 3. import the exported bookmarks file
+  // 4. run the test-suite
+
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await BookmarkHTMLUtils.exportToFile(gBookmarksFileNew);
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  await BookmarkHTMLUtils.importFromFile(gBookmarksFileNew, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+async function testImportedBookmarks() {
+  for (let group in test_bookmarks) {
+    info("[testImportedBookmarks()] Checking group '" + group + "'");
+
+    let root = PlacesUtils.getFolderContents(
+      PlacesUtils.bookmarks[`${group}Guid`]
+    ).root;
+
+    let items = test_bookmarks[group].filter(b => !b.ignore);
+    Assert.equal(root.childCount, items.length);
+
+    for (let key in items) {
+      await checkItem(items[key], root.getChild(key));
+    }
+
+    root.containerOpen = false;
+  }
+}
+
+function checkItem(aExpected, aNode) {
+  return (async function () {
+    let bookmark = await PlacesUtils.bookmarks.fetch(aNode.bookmarkGuid);
+
+    for (let prop in aExpected) {
+      switch (prop) {
+        case "type":
+          Assert.equal(aNode.type, aExpected.type);
+          break;
+        case "title":
+          Assert.equal(aNode.title, aExpected.title);
+          break;
+        case "dateAdded":
+          Assert.equal(
+            PlacesUtils.toPRTime(bookmark.dateAdded),
+            aExpected.dateAdded
+          );
+          break;
+        case "lastModified":
+          Assert.equal(
+            PlacesUtils.toPRTime(bookmark.lastModified),
+            aExpected.lastModified
+          );
+          break;
+        case "url":
+          Assert.equal(aNode.uri, aExpected.url);
+          break;
+        case "icon":
+          let { data } = await getFaviconDataForPage(aExpected.url);
+          let base64Icon =
+            "data:image/png;base64," +
+            base64EncodeString(String.fromCharCode.apply(String, data));
+          Assert.ok(base64Icon == aExpected.icon);
+          break;
+        case "keyword": {
+          let entry = await PlacesUtils.keywords.fetch({ url: aNode.uri });
+          Assert.equal(entry.keyword, aExpected.keyword);
+          break;
+        }
+        case "postData": {
+          let entry = await PlacesUtils.keywords.fetch({ url: aNode.uri });
+          Assert.equal(entry.postData, aExpected.postData);
+          break;
+        }
+        case "charset":
+          let pageInfo = await PlacesUtils.history.fetch(aNode.uri, {
+            includeAnnotations: true,
+          });
+          Assert.equal(
+            pageInfo.annotations.get(PlacesUtils.CHARSET_ANNO),
+            aExpected.charset
+          );
+          break;
+        case "feedUrl":
+          // No more supported.
+          break;
+        case "children":
+          let folder = aNode.QueryInterface(
+            Ci.nsINavHistoryContainerResultNode
+          );
+          Assert.equal(folder.hasChildren, !!aExpected.children.length);
+          folder.containerOpen = true;
+          Assert.equal(folder.childCount, aExpected.children.length);
+
+          for (let index = 0; index < aExpected.children.length; index++) {
+            await checkItem(aExpected.children[index], folder.getChild(index));
+          }
+
+          folder.containerOpen = false;
+          break;
+        default:
+          throw new Error("Unknown property");
+      }
+    }
+  })();
+}
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html_corrupt.js b/toolkit/components/places/tests/unit/test_bookmarks_html_corrupt.js
new file mode 100644
index 0000000000..061c8c0c5f
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html_corrupt.js
@@ -0,0 +1,126 @@
+/*
+ * This test ensures that importing/exporting to HTML does not stop
+ * if a malformed uri is found.
+ */
+
+const TEST_FAVICON_PAGE_URL =
+  "http://en-US.www.mozilla.com/en-US/firefox/central/";
+const TEST_FAVICON_DATA_SIZE = 580;
+
+add_task(async function test_corrupt_file() {
+  // Import bookmarks from the corrupt file.
+  let corruptHtml = PathUtils.join(do_get_cwd().path, "bookmarks.corrupt.html");
+  await BookmarkHTMLUtils.importFromFile(corruptHtml, { replace: true });
+
+  // Check that bookmarks that are not corrupt have been imported.
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await database_check();
+});
+
+add_task(async function test_corrupt_database() {
+  // Create corruption in the database, then export.
+  let corruptBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: "http://test.mozilla.org",
+    title: "We love belugas",
+  });
+  await PlacesUtils.withConnectionWrapper("test", async function (db) {
+    await db.execute("UPDATE moz_bookmarks SET fk = NULL WHERE guid = :guid", {
+      guid: corruptBookmark.guid,
+    });
+  });
+
+  let bookmarksFile = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.html"
+  );
+  await IOUtils.remove(bookmarksFile, { ignoreAbsent: true });
+  await BookmarkHTMLUtils.exportToFile(bookmarksFile);
+
+  // Import again and check for correctness.
+  await PlacesUtils.bookmarks.eraseEverything();
+  await BookmarkHTMLUtils.importFromFile(bookmarksFile, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await database_check();
+});
+
+/*
+ * Check for imported bookmarks correctness
+ *
+ * @return {Promise}
+ * @resolves When the checks are finished.
+ * @rejects Never.
+ */
+var database_check = async function () {
+  // BOOKMARKS MENU
+  let root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.menuGuid).root;
+  Assert.equal(root.childCount, 2);
+
+  let folderNode = root.getChild(1);
+  Assert.equal(folderNode.type, folderNode.RESULT_TYPE_FOLDER);
+  Assert.equal(folderNode.title, "test");
+
+  let bookmark = await PlacesUtils.bookmarks.fetch({
+    guid: folderNode.bookmarkGuid,
+  });
+  Assert.equal(PlacesUtils.toPRTime(bookmark.dateAdded), 1177541020000000);
+  Assert.equal(PlacesUtils.toPRTime(bookmark.lastModified), 1177541050000000);
+
+  // open test folder, and test the children
+  PlacesUtils.asQuery(folderNode);
+  Assert.equal(folderNode.hasChildren, true);
+  folderNode.containerOpen = true;
+  Assert.equal(folderNode.childCount, 1);
+
+  let bookmarkNode = folderNode.getChild(0);
+  Assert.equal("http://test/post", bookmarkNode.uri);
+  Assert.equal("test post keyword", bookmarkNode.title);
+
+  let entry = await PlacesUtils.keywords.fetch({ url: bookmarkNode.uri });
+  Assert.equal("test", entry.keyword);
+  Assert.equal("hidden1%3Dbar&text1%3D%25s", entry.postData);
+
+  Assert.equal(bookmarkNode.dateAdded, 1177375336000000);
+  Assert.equal(bookmarkNode.lastModified, 1177375423000000);
+
+  let pageInfo = await PlacesUtils.history.fetch(bookmarkNode.uri, {
+    includeAnnotations: true,
+  });
+  Assert.equal(
+    pageInfo.annotations.get(PlacesUtils.CHARSET_ANNO),
+    "ISO-8859-1",
+    "Should have the correct charset"
+  );
+
+  // clean up
+  folderNode.containerOpen = false;
+  root.containerOpen = false;
+
+  // BOOKMARKS TOOLBAR
+  root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.toolbarGuid).root;
+  Assert.equal(root.childCount, 3);
+
+  // cleanup
+  root.containerOpen = false;
+
+  // UNFILED BOOKMARKS
+  root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.unfiledGuid).root;
+  Assert.equal(root.childCount, 1);
+  root.containerOpen = false;
+
+  // favicons
+  await new Promise(resolve => {
+    PlacesUtils.favicons.getFaviconDataForPage(
+      uri(TEST_FAVICON_PAGE_URL),
+      (aURI, aDataLen, aData, aMimeType) => {
+        // aURI should never be null when aDataLen > 0.
+        Assert.notEqual(aURI, null);
+        // Favicon data is stored in the bookmarks file as a "data:" URI.  For
+        // simplicity, instead of converting the data we receive to a "data:" URI
+        // and comparing it, we just check the data size.
+        Assert.equal(TEST_FAVICON_DATA_SIZE, aDataLen);
+        resolve();
+      }
+    );
+  });
+};
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html_escape_entities.js b/toolkit/components/places/tests/unit/test_bookmarks_html_escape_entities.js
new file mode 100644
index 0000000000..5349d3948c
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html_escape_entities.js
@@ -0,0 +1,98 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Checks that html entities are escaped in bookmarks.html files.
+
+add_task(async function () {
+  // Removes bookmarks.html if the file already exists.
+  let HTMLFile = PathUtils.join(PathUtils.profileDir, "bookmarks.html");
+  await IOUtils.remove(HTMLFile, { ignoreAbsent: true });
+
+  let unescaped = '<unescaped="test">';
+  // Adds bookmarks and tags to the database.
+  const url = 'http://www.google.it/"/';
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url,
+    title: unescaped,
+  });
+  await PlacesUtils.keywords.insert({
+    url,
+    keyword: unescaped,
+    postData: unescaped,
+  });
+  PlacesUtils.tagging.tagURI(Services.io.newURI(url), [unescaped]);
+  await PlacesUtils.history.update({
+    url,
+    annotations: new Map([[PlacesUtils.CHARSET_ANNO, unescaped]]),
+  });
+
+  // Exports the bookmarks as a HTML file.
+  await BookmarkHTMLUtils.exportToFile(HTMLFile);
+  await PlacesUtils.bookmarks.remove(bm);
+
+  // Check there are no unescaped entities in the html file.
+  let xml = await new Promise((resolve, reject) => {
+    let xhr = new XMLHttpRequest();
+    xhr.onload = () => {
+      try {
+        resolve(xhr.responseXML);
+      } catch (e) {
+        reject(e);
+      }
+    };
+    xhr.onabort =
+      xhr.onerror =
+      xhr.ontimeout =
+        () => {
+          reject(new Error("xmlhttprequest failed"));
+        };
+    xhr.open("GET", PathUtils.toFileURI(HTMLFile));
+    xhr.responseType = "document";
+    xhr.overrideMimeType("text/html");
+    xhr.send();
+  });
+
+  let checksCount = 5;
+  for (
+    let current = xml;
+    current;
+    current =
+      current.firstChild ||
+      current.nextSibling ||
+      current.parentNode.nextSibling
+  ) {
+    switch (current.nodeType) {
+      case current.ELEMENT_NODE:
+        for (let { name, value } of current.attributes) {
+          info("Found attribute: " + name);
+          // Check tags, keyword, postData and charSet.
+          if (
+            ["tags", "last_charset", "shortcuturl", "post_data"].includes(name)
+          ) {
+            Assert.equal(
+              value,
+              unescaped,
+              `Attribute ${name} should be complete`
+            );
+            checksCount--;
+          }
+        }
+        break;
+      case current.TEXT_NODE:
+        // Check Title.
+        if (!current.data.startsWith("\n") && current.data.includes("test")) {
+          Assert.equal(
+            current.data.trim(),
+            unescaped,
+            "Text node should be complete"
+          );
+          checksCount--;
+        }
+        break;
+    }
+  }
+  Assert.equal(checksCount, 0, "All the checks ran");
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html_import_tags.js b/toolkit/components/places/tests/unit/test_bookmarks_html_import_tags.js
new file mode 100644
index 0000000000..f01048e1a5
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html_import_tags.js
@@ -0,0 +1,64 @@
+var bookmarkData = [
+  {
+    uri: uri("http://www.toastytech.com"),
+    title: "Nathan's Toasty Technology Page",
+    tags: ["technology", "personal", "retro"],
+  },
+  {
+    uri: uri("http://www.reddit.com"),
+    title: "reddit: the front page of the internet",
+    tags: ["social media", "news", "humour"],
+  },
+  {
+    uri: uri("http://www.4chan.org"),
+    title: "4chan",
+    tags: ["discussion", "imageboard", "anime"],
+  },
+];
+
+/*
+  TEST SUMMARY
+  - Add bookmarks with tags
+  - Export tagged bookmarks as HTML file
+  - Delete bookmarks
+  - Import bookmarks from HTML file
+  - Check that all bookmarks are successfully imported with tags
+*/
+
+add_task(async function test_import_tags() {
+  // Removes bookmarks.html if the file already exists.
+  let HTMLFile = PathUtils.join(PathUtils.profileDir, "bookmarks.html");
+  await IOUtils.remove(HTMLFile, { ignoreAbsent: true });
+
+  // Adds bookmarks and tags to the database.
+  let bookmarkList = new Set();
+  for (let { uri, title, tags } of bookmarkData) {
+    bookmarkList.add(
+      await PlacesUtils.bookmarks.insert({
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+        url: uri,
+        title,
+      })
+    );
+    PlacesUtils.tagging.tagURI(uri, tags);
+  }
+
+  // Exports the bookmarks as a HTML file.
+  await BookmarkHTMLUtils.exportToFile(HTMLFile);
+
+  // Deletes bookmarks and tags from the database.
+  for (let bookmark of bookmarkList) {
+    await PlacesUtils.bookmarks.remove(bookmark.guid);
+  }
+
+  // Re-imports the bookmarks from the HTML file.
+  await BookmarkHTMLUtils.importFromFile(HTMLFile, { replace: true });
+
+  // Tests to ensure that the tags are still present for each bookmark URI.
+  for (let { uri, tags } of bookmarkData) {
+    info("Test tags for " + uri.spec + ": " + tags + "\n");
+    let foundTags = PlacesUtils.tagging.getTagsForURI(uri);
+    Assert.equal(foundTags.length, tags.length);
+    Assert.ok(tags.every(tag => foundTags.includes(tag)));
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html_localized.js b/toolkit/components/places/tests/unit/test_bookmarks_html_localized.js
new file mode 100644
index 0000000000..4ef2393efb
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html_localized.js
@@ -0,0 +1,51 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const { BookmarkHTMLUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/BookmarkHTMLUtils.sys.mjs"
+);
+
+add_task(async function setup_l10n() {
+  // A single localized string.
+  const mockSource = L10nFileSource.createMock(
+    "test",
+    "app",
+    ["en-US"],
+    "/localization/{locale}/",
+    [
+      {
+        path: "/localization/en-US/bookmarks_html_localized.ftl",
+        source: `
+bookmarks-html-localized-folder = Localized Folder
+bookmarks-html-localized-bookmark = Localized Bookmark
+`,
+      },
+    ]
+  );
+
+  L10nRegistry.getInstance().registerSources([mockSource]);
+});
+
+add_task(async function test_bookmarks_html_localized() {
+  let bookmarksFile = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks_html_localized.html"
+  );
+  await BookmarkHTMLUtils.importFromFile(bookmarksFile, { replace: true });
+
+  let root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.menuGuid).root;
+  Assert.equal(root.childCount, 1);
+  let folder = root.getChild(0);
+  PlacesUtils.asContainer(folder).containerOpen = true;
+  // Folder title is localized.
+  Assert.equal(folder.title, "Localized Folder");
+  Assert.equal(folder.childCount, 1);
+  let bookmark = folder.getChild(0);
+  Assert.equal(bookmark.uri, "http://www.mozilla.com/firefox/help/");
+  // Bookmark title is localized.
+  Assert.equal(bookmark.title, "Localized Bookmark");
+  folder.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_html_singleframe.js b/toolkit/components/places/tests/unit/test_bookmarks_html_singleframe.js
new file mode 100644
index 0000000000..07131feafe
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_html_singleframe.js
@@ -0,0 +1,31 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Test for bug #801450
+
+// Get Services
+const { BookmarkHTMLUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/BookmarkHTMLUtils.sys.mjs"
+);
+
+add_task(async function test_bookmarks_html_singleframe() {
+  let bookmarksFile = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks_html_singleframe.html"
+  );
+  await BookmarkHTMLUtils.importFromFile(bookmarksFile, { replace: true });
+
+  let root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.menuGuid).root;
+  Assert.equal(root.childCount, 1);
+  let folder = root.getChild(0);
+  PlacesUtils.asContainer(folder).containerOpen = true;
+  Assert.equal(folder.title, "Subtitle");
+  Assert.equal(folder.childCount, 1);
+  let bookmark = folder.getChild(0);
+  Assert.equal(bookmark.uri, "http://www.mozilla.org/");
+  Assert.equal(bookmark.title, "Mozilla");
+  folder.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_json.js b/toolkit/components/places/tests/unit/test_bookmarks_json.js
new file mode 100644
index 0000000000..19aaac7f95
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_json.js
@@ -0,0 +1,368 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const { BookmarkJSONUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/BookmarkJSONUtils.sys.mjs"
+);
+
+// An object representing the contents of bookmarks.json.
+var test_bookmarks = {
+  menu: [
+    {
+      guid: "OCyeUO5uu9FF",
+      title: "Mozilla Firefox",
+      children: [
+        {
+          guid: "OCyeUO5uu9FG",
+          title: "Help and Tutorials",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/help/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          guid: "OCyeUO5uu9FH",
+          title: "Customize Firefox",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/customize/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          guid: "OCyeUO5uu9FI",
+          title: "Get Involved",
+          url: "http://en-us.www.mozilla.com/en-US/firefox/community/",
+          icon: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABGdBTUEAAK/INwWK6QAAABl0RVh0U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAHWSURBVHjaYvz//z8DJQAggJiQOe/fv2fv7Oz8rays/N+VkfG/iYnJfyD/1+rVq7ffu3dPFpsBAAHEAHIBCJ85c8bN2Nj4vwsDw/8zQLwKiO8CcRoQu0DxqlWrdsHUwzBAAIGJmTNnPgYa9j8UqhFElwPxf2MIDeIrKSn9FwSJoRkAEEAM0DD4DzMAyPi/G+QKY4hh5WAXGf8PDQ0FGwJ22d27CjADAAIIrLmjo+MXA9R2kAHvGBA2wwx6B8W7od6CeQcggKCmCEL8bgwxYCbUIGTDVkHDBia+CuotgACCueD3TDQN75D4xmAvCoK9ARMHBzAw0AECiBHkAlC0Mdy7x9ABNA3obAZXIAa6iKEcGlMVQHwWyjYuL2d4v2cPg8vZswx7gHyAAAK7AOif7SAbOqCmn4Ha3AHFsIDtgPq/vLz8P4MSkJ2W9h8ggBjevXvHDo4FQUQg/kdypqCg4H8lUIACnQ/SOBMYI8bAsAJFPcj1AAEEjwVQqLpAbXmH5BJjqI0gi9DTAAgDBBCcAVLkgmQ7yKCZxpCQxqUZhAECCJ4XgMl493ug21ZD+aDAXH0WLM4A9MZPXJkJIIAwTAR5pQMalaCABQUULttBGCCAGCnNzgABBgAMJ5THwGvJLAAAAABJRU5ErkJggg==",
+        },
+        {
+          guid: "OCyeUO5uu9FJ",
+          title: "About Us",
+          url: "http://en-us.www.mozilla.com/en-US/about/",
+          icon: "data:image/png;base64,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",
+        },
+        {
+          guid: "QFM-QnE2ZpMz",
+          title: "Test null postData",
+          url: "http://example.com/search?q=%s&suggid=",
+        },
+      ],
+    },
+    {
+      guid: "OCyeUO5uu9FK",
+      type: Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR,
+    },
+    {
+      guid: "OCyeUO5uu9FL",
+      title: "test",
+      dateAdded: 1177541020000000,
+      lastModified: 1177541050000000,
+      children: [
+        {
+          guid: "OCyeUO5uu9GX",
+          title: "test post keyword",
+          dateAdded: 1177375336000000,
+          lastModified: 1177375423000000,
+          keyword: "test",
+          postData: "hidden1%3Dbar&text1%3D%25s",
+          charset: "ISO-8859-1",
+        },
+      ],
+    },
+  ],
+  toolbar: [
+    {
+      guid: "OCyeUO5uu9FB",
+      title: "Getting Started",
+      url: "http://en-us.www.mozilla.com/en-US/firefox/central/",
+      icon: "data:image/png;base64,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",
+    },
+    {
+      guid: "OCyeUO5uu9FR",
+      title: "Latest Headlines",
+      // This used to be a livemark, but we don't import them anymore, instead
+      // it will be imported as an empty folder, because the json format stores
+      // it like that: an empty folder with a couple annotations. Since
+      // annotations will go away, there won't be a clean way to import it as a
+      // bookmark instead.
+      // Note: date gets truncated to milliseconds, whereas the value in bookmarks.json
+      // has full microseconds.
+      dateAdded: 1361551979451000,
+      lastModified: 1361551979457000,
+    },
+  ],
+  unfiled: [
+    { guid: "OCyeUO5uu9FW", title: "Example.tld", url: "http://example.tld/" },
+    {
+      guid: "Cfkety492Afk",
+      title: "test tagged bookmark",
+      dateAdded: 1507025843703000,
+      lastModified: 1507025844703000,
+      url: "http://example.tld/tagged",
+      tags: ["foo"],
+    },
+    {
+      guid: "lOZGoFR1eXbl",
+      title: "Bookmarks Toolbar Shortcut",
+      dateAdded: 1507025843703000,
+      lastModified: 1507025844703000,
+      url: `place:parent=${PlacesUtils.bookmarks.toolbarGuid}`,
+    },
+    {
+      guid: "7yJWnBVhjRtP",
+      title: "Folder Shortcut",
+      dateAdded: 1507025843703000,
+      lastModified: 1507025844703000,
+      url: `place:parent=OCyeUO5uu9FF`,
+    },
+    {
+      guid: "vm5QXWuWc12l",
+      title: "Folder Shortcut 2",
+      dateAdded: 1507025843703000,
+      lastModified: 1507025844703000,
+      url: "place:invalidOldParentId=6123443&excludeItems=1",
+    },
+    {
+      guid: "Icg1XlIozA1D",
+      title: "Folder Shortcut 3",
+      dateAdded: 1507025843703000,
+      lastModified: 1507025844703000,
+      url: `place:parent=OCyeUO5uu9FF&parent=${PlacesUtils.bookmarks.menuGuid}`,
+    },
+  ],
+};
+
+// Exported bookmarks file pointer.
+var bookmarksExportedFile;
+
+add_task(async function test_import_bookmarks_disallowed_url() {
+  await Assert.rejects(
+    BookmarkJSONUtils.importFromURL("http://example.com/bookmarks.json"),
+    /importFromURL can only be used with/,
+    "Should reject importing from an http based url"
+  );
+  await Assert.rejects(
+    BookmarkJSONUtils.importFromURL("https://example.com/bookmarks.json"),
+    /importFromURL can only be used with/,
+    "Should reject importing from an https based url"
+  );
+});
+
+add_task(async function test_import_bookmarks_count() {
+  // Ensure the bookmarks count is correct when importing in various cases
+  await PlacesUtils.bookmarks.eraseEverything();
+  let bookmarksFile = PathUtils.join(do_get_cwd().path, "bookmarks.json");
+  bookmarksExportedFile = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.json"
+  );
+
+  let count = await BookmarkJSONUtils.importFromFile(bookmarksFile, {
+    replace: true,
+  });
+  Assert.equal(
+    count,
+    13,
+    "There should be 13 imported bookmarks when importing from an empty database"
+  );
+
+  await BookmarkJSONUtils.exportToFile(bookmarksExportedFile);
+  count = -1;
+  count = await BookmarkJSONUtils.importFromFile(bookmarksExportedFile, {
+    replace: true,
+  });
+  Assert.equal(
+    count,
+    13,
+    "There should be 13 imported bookmarks when replacing existing bookmarks"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  count = -1;
+  let bookmarksUrl = PathUtils.toFileURI(bookmarksFile);
+  count = await BookmarkJSONUtils.importFromURL(bookmarksUrl);
+  Assert.equal(
+    count,
+    13,
+    "There should be 13 imported bookmarks when importing from a URL"
+  );
+
+  // Clean up task
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_bookmarks() {
+  let bookmarksFile = PathUtils.join(do_get_cwd().path, "bookmarks.json");
+
+  await BookmarkJSONUtils.importFromFile(bookmarksFile, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+});
+
+add_task(async function test_export_bookmarks() {
+  bookmarksExportedFile = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.json"
+  );
+  await BookmarkJSONUtils.exportToFile(bookmarksExportedFile);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_import_exported_bookmarks() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await BookmarkJSONUtils.importFromFile(bookmarksExportedFile, {
+    replace: true,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+});
+
+add_task(async function test_import_ontop() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await BookmarkJSONUtils.importFromFile(bookmarksExportedFile, {
+    replace: true,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await BookmarkJSONUtils.exportToFile(bookmarksExportedFile);
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await BookmarkJSONUtils.importFromFile(bookmarksExportedFile, {
+    replace: true,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+});
+
+add_task(async function test_import_iconuri() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+
+  let bookmarksFile = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks_iconuri.json"
+  );
+
+  await BookmarkJSONUtils.importFromFile(bookmarksFile, {
+    replace: true,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+});
+
+add_task(async function test_export_bookmarks_with_iconuri() {
+  bookmarksExportedFile = PathUtils.join(
+    PathUtils.profileDir,
+    "bookmarks.exported.json"
+  );
+  await BookmarkJSONUtils.exportToFile(bookmarksExportedFile);
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function test_import_exported_bookmarks_with_iconuri() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+  await BookmarkJSONUtils.importFromFile(bookmarksExportedFile, {
+    replace: true,
+  });
+  await PlacesTestUtils.promiseAsyncUpdates();
+  await testImportedBookmarks();
+});
+
+add_task(async function test_clean() {
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+async function testImportedBookmarks() {
+  for (let group in test_bookmarks) {
+    info("[testImportedBookmarks()] Checking group '" + group + "'");
+
+    let root = PlacesUtils.getFolderContents(
+      PlacesUtils.bookmarks[`${group}Guid`]
+    ).root;
+
+    let items = test_bookmarks[group];
+    Assert.equal(root.childCount, items.length);
+
+    for (let key in items) {
+      await checkItem(items[key], root.getChild(key));
+    }
+
+    root.containerOpen = false;
+  }
+}
+
+async function checkItem(aExpected, aNode) {
+  let bookmark = await PlacesUtils.bookmarks.fetch(aNode.bookmarkGuid);
+
+  for (let prop in aExpected) {
+    switch (prop) {
+      case "type":
+        Assert.equal(aNode.type, aExpected.type);
+        break;
+      case "title":
+        Assert.equal(aNode.title, aExpected.title);
+        break;
+      case "dateAdded":
+        Assert.equal(
+          PlacesUtils.toPRTime(bookmark.dateAdded),
+          aExpected.dateAdded
+        );
+        break;
+      case "lastModified":
+        Assert.equal(
+          PlacesUtils.toPRTime(bookmark.lastModified),
+          aExpected.lastModified
+        );
+        break;
+      case "url":
+        Assert.equal(aNode.uri, aExpected.url);
+        break;
+      case "icon":
+        let { data } = await getFaviconDataForPage(aExpected.url);
+        let base64Icon =
+          "data:image/png;base64," +
+          base64EncodeString(String.fromCharCode.apply(String, data));
+        Assert.equal(base64Icon, aExpected.icon);
+        break;
+      case "keyword": {
+        let entry = await PlacesUtils.keywords.fetch({ url: aNode.uri });
+        Assert.equal(entry.keyword, aExpected.keyword);
+        break;
+      }
+      case "guid":
+        Assert.equal(bookmark.guid, aExpected.guid);
+        break;
+      case "postData": {
+        let entry = await PlacesUtils.keywords.fetch({ url: aNode.uri });
+        Assert.equal(entry.postData, aExpected.postData);
+        break;
+      }
+      case "charset":
+        let pageInfo = await PlacesUtils.history.fetch(aNode.uri, {
+          includeAnnotations: true,
+        });
+        Assert.equal(
+          pageInfo.annotations.get(PlacesUtils.CHARSET_ANNO),
+          aExpected.charset
+        );
+        break;
+      case "children":
+        let folder = aNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
+        Assert.equal(folder.hasChildren, !!aExpected.children.length);
+        folder.containerOpen = true;
+        Assert.equal(folder.childCount, aExpected.children.length);
+
+        for (let index = 0; index < aExpected.children.length; index++) {
+          await checkItem(aExpected.children[index], folder.getChild(index));
+        }
+
+        folder.containerOpen = false;
+        break;
+      case "tags":
+        let uri = Services.io.newURI(aNode.uri);
+        Assert.deepEqual(
+          PlacesUtils.tagging.getTagsForURI(uri),
+          aExpected.tags,
+          "should have the expected tags"
+        );
+        break;
+      default:
+        throw new Error("Unknown property");
+    }
+  }
+}
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_json_corrupt.js b/toolkit/components/places/tests/unit/test_bookmarks_json_corrupt.js
new file mode 100644
index 0000000000..b31f1da5bb
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_json_corrupt.js
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Tests for importing a corrupt json file.
+ *
+ * The corrupt json file attempts to import into:
+ *   - the menu folder:
+ *     - A bookmark with an invalid type.
+ *     - A valid bookmark.
+ *     - A bookmark with an invalid url.
+ *   - the toolbar folder:
+ *     - A bookmark with an invalid url.
+ *
+ * The menu case ensure that we strip out invalid bookmarks, but retain valid
+ * ones.
+ * The toolbar case ensures that if no valid bookmarks remain, then we do not
+ * throw an error.
+ */
+
+const { BookmarkJSONUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/BookmarkJSONUtils.sys.mjs"
+);
+
+add_task(async function test_import_bookmarks() {
+  let bookmarksFile = PathUtils.join(
+    do_get_cwd().path,
+    "bookmarks_corrupt.json"
+  );
+
+  await BookmarkJSONUtils.importFromFile(bookmarksFile, { replace: true });
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  let bookmarks = await PlacesUtils.promiseBookmarksTree(
+    PlacesUtils.bookmarks.menuGuid
+  );
+
+  Assert.equal(
+    bookmarks.children.length,
+    1,
+    "should only be one bookmark in the menu"
+  );
+  let bookmark = bookmarks.children[0];
+  Assert.equal(bookmark.guid, "OCyeUO5uu9FH", "should have correct guid");
+  Assert.equal(
+    bookmark.title,
+    "Customize Firefox",
+    "should have correct title"
+  );
+  Assert.equal(
+    bookmark.uri,
+    "http://en-us.www.mozilla.com/en-US/firefox/customize/",
+    "should have correct uri"
+  );
+
+  bookmarks = await PlacesUtils.promiseBookmarksTree(
+    PlacesUtils.bookmarks.toolbarGuid
+  );
+
+  Assert.ok(
+    !bookmarks.children,
+    "should not have any bookmarks in the toolbar"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_bookmarks_restore_notification.js b/toolkit/components/places/tests/unit/test_bookmarks_restore_notification.js
new file mode 100644
index 0000000000..892b2d1d04
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_bookmarks_restore_notification.js
@@ -0,0 +1,319 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const { BookmarkHTMLUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/BookmarkHTMLUtils.sys.mjs"
+);
+
+/**
+ * Tests the bookmarks-restore-* nsIObserver notifications after restoring
+ * bookmarks from JSON and HTML.  See bug 470314.
+ */
+
+// The topics and data passed to nsIObserver.observe() on bookmarks restore
+const NSIOBSERVER_TOPIC_BEGIN = "bookmarks-restore-begin";
+const NSIOBSERVER_TOPIC_SUCCESS = "bookmarks-restore-success";
+const NSIOBSERVER_TOPIC_FAILED = "bookmarks-restore-failed";
+const NSIOBSERVER_DATA_JSON = "json";
+const NSIOBSERVER_DATA_HTML = "html";
+const NSIOBSERVER_DATA_HTML_INIT = "html-initial";
+
+// Bookmarks are added for these URIs
+var uris = [
+  "http://example.com/1",
+  "http://example.com/2",
+  "http://example.com/3",
+  "http://example.com/4",
+  "http://example.com/5",
+];
+
+/**
+ * Adds some bookmarks for the URIs in |uris|.
+ */
+async function addBookmarks() {
+  for (let url of uris) {
+    await PlacesUtils.bookmarks.insert({
+      url,
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+    });
+    Assert.ok(await PlacesUtils.bookmarks.fetch({ url }), "Url is bookmarked");
+  }
+}
+
+/**
+ * Creates an file in the profile directory.
+ *
+ * @param  aBasename
+ *         e.g., "foo.txt" in the path /some/long/path/foo.txt
+ * @return {Promise}
+ * @resolves to an OS.File path
+ */
+async function promiseFile(aBasename) {
+  let path = PathUtils.join(PathUtils.profileDir, aBasename);
+  info("opening " + path);
+
+  await IOUtils.writeUTF8(path, "");
+  return path;
+}
+
+/**
+ * Register observers via promiseTopicObserved helper.
+ *
+ * @param  {boolean} expectSuccess pass true when expect a success notification
+ * @return {Promise[]}
+ */
+function registerObservers(expectSuccess) {
+  let promiseBegin = promiseTopicObserved(NSIOBSERVER_TOPIC_BEGIN);
+  let promiseResult;
+  if (expectSuccess) {
+    promiseResult = promiseTopicObserved(NSIOBSERVER_TOPIC_SUCCESS);
+  } else {
+    promiseResult = promiseTopicObserved(NSIOBSERVER_TOPIC_FAILED);
+  }
+
+  return [promiseBegin, promiseResult];
+}
+
+/**
+ * Check notification results.
+ *
+ * @param  {Promise[]} expectPromises array contain promiseBegin and promiseResult
+ * @param  {object} expectedData contain data and folderId
+ */
+async function checkObservers(expectPromises, expectedData) {
+  let [promiseBegin, promiseResult] = expectPromises;
+
+  let beginData = (await promiseBegin)[1];
+  Assert.equal(
+    beginData,
+    expectedData.data,
+    "Data for current test should be what is expected"
+  );
+
+  let [resultSubject, resultData] = await promiseResult;
+  Assert.equal(
+    resultData,
+    expectedData.data,
+    "Data for current test should be what is expected"
+  );
+
+  // Make sure folder ID is what is expected.  For importing HTML into a
+  // folder, this will be an integer, otherwise null.
+  if (resultSubject) {
+    Assert.equal(
+      resultSubject.QueryInterface(Ci.nsISupportsPRInt64).data,
+      expectedData.folderId
+    );
+  } else {
+    Assert.equal(expectedData.folderId, null);
+  }
+}
+
+/**
+ * Run after every test cases.
+ */
+async function teardown(file, begin, success, fail) {
+  // On restore failed, file may not exist, so wrap in try-catch.
+  await IOUtils.remove(file, { ignoreAbsent: true });
+
+  // clean up bookmarks
+  await PlacesUtils.bookmarks.eraseEverything();
+}
+
+add_task(async function test_json_restore_normal() {
+  // data: the data passed to nsIObserver.observe() corresponding to the test
+  // folderId: for HTML restore into a folder, the folder ID to restore into;
+  //           otherwise, set it to null
+  let expectedData = {
+    data: NSIOBSERVER_DATA_JSON,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(true);
+
+  info("JSON restore: normal restore should succeed");
+  let file = await promiseFile("bookmarks-test_restoreNotification.json");
+  await addBookmarks();
+
+  await BookmarkJSONUtils.exportToFile(file);
+  await PlacesUtils.bookmarks.eraseEverything();
+  try {
+    await BookmarkJSONUtils.importFromFile(file, { replace: true });
+  } catch (e) {
+    do_throw("  Restore should not have failed " + e);
+  }
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_json_restore_empty() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_JSON,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(false);
+
+  info("JSON restore: empty file should fail");
+  let file = await promiseFile("bookmarks-test_restoreNotification.json");
+  await Assert.rejects(
+    BookmarkJSONUtils.importFromFile(file, { replace: true }),
+    /SyntaxError/,
+    "Restore should reject for an empty file."
+  );
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_json_restore_nonexist() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_JSON,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(false);
+
+  info("JSON restore: nonexistent file should fail");
+  let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append("this file doesn't exist because nobody created it 1");
+  await Assert.rejects(
+    BookmarkJSONUtils.importFromFile(file.path, { replace: true }),
+    /Cannot restore from nonexisting json file/,
+    "Restore should reject for a non-existent file."
+  );
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file.path);
+});
+
+add_task(async function test_html_restore_normal() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(true);
+
+  info("HTML restore: normal restore should succeed");
+  let file = await promiseFile("bookmarks-test_restoreNotification.html");
+  await addBookmarks();
+  await BookmarkHTMLUtils.exportToFile(file);
+  await PlacesUtils.bookmarks.eraseEverything();
+  try {
+    BookmarkHTMLUtils.importFromFile(file).catch(
+      do_report_unexpected_exception
+    );
+  } catch (e) {
+    do_throw("  Restore should not have failed");
+  }
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_html_restore_empty() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(true);
+
+  info("HTML restore: empty file should succeed");
+  let file = await promiseFile("bookmarks-test_restoreNotification.init.html");
+  try {
+    BookmarkHTMLUtils.importFromFile(file).catch(
+      do_report_unexpected_exception
+    );
+  } catch (e) {
+    do_throw("  Restore should not have failed");
+  }
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_html_restore_nonexist() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(false);
+
+  info("HTML restore: nonexistent file should fail");
+  let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append("this file doesn't exist because nobody created it 2");
+  await Assert.rejects(
+    BookmarkHTMLUtils.importFromFile(file.path),
+    /Cannot import from nonexisting html file/,
+    "Restore should reject for a non-existent file."
+  );
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file.path);
+});
+
+add_task(async function test_html_init_restore_normal() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML_INIT,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(true);
+
+  info("HTML initial restore: normal restore should succeed");
+  let file = await promiseFile("bookmarks-test_restoreNotification.init.html");
+  await addBookmarks();
+  await BookmarkHTMLUtils.exportToFile(file);
+  await PlacesUtils.bookmarks.eraseEverything();
+  try {
+    BookmarkHTMLUtils.importFromFile(file, { replace: true }).catch(
+      do_report_unexpected_exception
+    );
+  } catch (e) {
+    do_throw("  Restore should not have failed");
+  }
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_html_init_restore_empty() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML_INIT,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(true);
+
+  info("HTML initial restore: empty file should succeed");
+  let file = await promiseFile("bookmarks-test_restoreNotification.init.html");
+  try {
+    BookmarkHTMLUtils.importFromFile(file, { replace: true }).catch(
+      do_report_unexpected_exception
+    );
+  } catch (e) {
+    do_throw("  Restore should not have failed");
+  }
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file);
+});
+
+add_task(async function test_html_init_restore_nonexist() {
+  let expectedData = {
+    data: NSIOBSERVER_DATA_HTML_INIT,
+    folderId: null,
+  };
+  let expectPromises = registerObservers(false);
+
+  info("HTML initial restore: nonexistent file should fail");
+  let file = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  file.append("this file doesn't exist because nobody created it 3");
+  await Assert.rejects(
+    BookmarkHTMLUtils.importFromFile(file.path, { replace: true }),
+    /Cannot import from nonexisting html file/,
+    "Restore should reject for a non-existent file."
+  );
+
+  await checkObservers(expectPromises, expectedData);
+  await teardown(file.path);
+});
diff --git a/toolkit/components/places/tests/unit/test_broken_folderShortcut_result.js b/toolkit/components/places/tests/unit/test_broken_folderShortcut_result.js
new file mode 100644
index 0000000000..1e1f7bc9c7
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_broken_folderShortcut_result.js
@@ -0,0 +1,78 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_brokenFolderShortcut() {
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        url: "http://1.moz.org/",
+        title: "Bookmark 1",
+      },
+      {
+        url: "place:parent=1234",
+        title: "Shortcut 1",
+      },
+      {
+        url: "place:parent=-1",
+        title: "Shortcut 2",
+      },
+      {
+        url: "http://2.moz.org/",
+        title: "Bookmark 2",
+      },
+    ],
+  });
+
+  // Add also a simple visit.
+  await PlacesTestUtils.addVisits(uri("http://3.moz.org/"));
+
+  // Query containing a broken folder shortcuts among results.
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.unfiledGuid]);
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  Assert.equal(root.childCount, 4);
+
+  let shortcut = root.getChild(1);
+  Assert.equal(shortcut.uri, "place:parent=1234");
+  PlacesUtils.asContainer(shortcut);
+  shortcut.containerOpen = true;
+  Assert.equal(shortcut.childCount, 0);
+  shortcut.containerOpen = false;
+  // Remove the broken shortcut while the containing result is open.
+  await PlacesUtils.bookmarks.remove(bookmarks[1]);
+  Assert.equal(root.childCount, 3);
+
+  shortcut = root.getChild(1);
+  Assert.equal(shortcut.uri, "place:parent=-1");
+  PlacesUtils.asContainer(shortcut);
+  shortcut.containerOpen = true;
+  Assert.equal(shortcut.childCount, 0);
+  shortcut.containerOpen = false;
+  // Remove the broken shortcut while the containing result is open.
+  await PlacesUtils.bookmarks.remove(bookmarks[2]);
+  Assert.equal(root.childCount, 2);
+
+  root.containerOpen = false;
+
+  // Broken folder shortcut as root node.
+  query = PlacesUtils.history.getNewQuery();
+  query.setParents([1234]);
+  options = PlacesUtils.history.getNewQueryOptions();
+  root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+
+  // Broken folder shortcut as root node with folder=-1.
+  query = PlacesUtils.history.getNewQuery();
+  query.setParents([-1]);
+  options = PlacesUtils.history.getNewQueryOptions();
+  root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 0);
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_browserhistory.js b/toolkit/components/places/tests/unit/test_browserhistory.js
new file mode 100644
index 0000000000..f737262ae7
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_browserhistory.js
@@ -0,0 +1,122 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const TEST_URI = "http://mozilla.com/";
+const TEST_SUBDOMAIN_URI = "http://foobar.mozilla.com/";
+
+async function checkEmptyHistory() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.executeCached("SELECT count(*) FROM moz_historyvisits");
+  return !rows[0].getResultByIndex(0);
+}
+
+add_task(async function test_addPage() {
+  await PlacesTestUtils.addVisits(TEST_URI);
+  Assert.ok(!(await checkEmptyHistory()), "History has entries");
+});
+
+add_task(async function test_removePage() {
+  await PlacesUtils.history.remove(TEST_URI);
+  Assert.ok(await checkEmptyHistory(), "History is empty");
+});
+
+add_task(async function test_removePages() {
+  let pages = [];
+  for (let i = 0; i < 8; i++) {
+    pages.push(TEST_URI + i);
+  }
+
+  await PlacesTestUtils.addVisits(pages.map(uri => ({ uri })));
+  // Bookmarked item should not be removed from moz_places.
+  const ANNO_INDEX = 1;
+  const ANNO_NAME = "testAnno";
+  const ANNO_VALUE = "foo";
+  const BOOKMARK_INDEX = 2;
+  await PlacesUtils.history.update({
+    url: pages[ANNO_INDEX],
+    annotations: new Map([[ANNO_NAME, ANNO_VALUE]]),
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: pages[BOOKMARK_INDEX],
+    title: "test bookmark",
+  });
+  await PlacesUtils.history.update({
+    url: pages[BOOKMARK_INDEX],
+    annotations: new Map([[ANNO_NAME, ANNO_VALUE]]),
+  });
+
+  await PlacesUtils.history.remove(pages);
+  Assert.ok(await checkEmptyHistory(), "History is empty");
+
+  // Check that the bookmark and its annotation still exist.
+  let folder = await PlacesUtils.getFolderContents(
+    PlacesUtils.bookmarks.unfiledGuid
+  );
+  Assert.equal(folder.root.childCount, 1);
+  let pageInfo = await PlacesUtils.history.fetch(pages[BOOKMARK_INDEX], {
+    includeAnnotations: true,
+  });
+  Assert.equal(pageInfo.annotations.get(ANNO_NAME), ANNO_VALUE);
+
+  // Check the annotation on the non-bookmarked page does not exist anymore.
+  await assertNoOrphanPageAnnotations();
+
+  // Cleanup.
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_removePagesByTimeframe() {
+  let visits = [];
+  let startDate = (Date.now() - 10000) * 1000;
+  for (let i = 0; i < 10; i++) {
+    visits.push({
+      uri: TEST_URI + i,
+      visitDate: startDate + i * 1000,
+    });
+  }
+
+  await PlacesTestUtils.addVisits(visits);
+
+  // Delete all pages except the first and the last.
+  await PlacesUtils.history.removeByFilter({
+    beginDate: PlacesUtils.toDate(startDate + 1000),
+    endDate: PlacesUtils.toDate(startDate + 8000),
+  });
+
+  // Check that we have removed the correct pages.
+  for (let i = 0; i < 10; i++) {
+    Assert.equal(page_in_database(TEST_URI + i) == 0, i > 0 && i < 9);
+  }
+
+  // Clear remaining items and check that all pages have been removed.
+  await PlacesUtils.history.removeByFilter({
+    beginDate: PlacesUtils.toDate(startDate),
+    endDate: PlacesUtils.toDate(startDate + 9000),
+  });
+  Assert.ok(await checkEmptyHistory(), "History is empty");
+});
+
+add_task(async function test_removePagesFromHost() {
+  await PlacesTestUtils.addVisits(TEST_URI);
+  await PlacesUtils.history.removeByFilter({ host: ".mozilla.com" });
+  Assert.ok(await checkEmptyHistory(), "History is empty");
+});
+
+add_task(async function test_removePagesFromHost_keepSubdomains() {
+  await PlacesTestUtils.addVisits([
+    { uri: TEST_URI },
+    { uri: TEST_SUBDOMAIN_URI },
+  ]);
+  await PlacesUtils.history.removeByFilter({ host: "mozilla.com" });
+  Assert.ok(!(await checkEmptyHistory()), "History has entries");
+});
+
+add_task(async function test_history_clear() {
+  await PlacesUtils.history.clear();
+  Assert.ok(await checkEmptyHistory(), "History is empty");
+});
diff --git a/toolkit/components/places/tests/unit/test_childlessTags.js b/toolkit/components/places/tests/unit/test_childlessTags.js
new file mode 100644
index 0000000000..9f489a266b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_childlessTags.js
@@ -0,0 +1,140 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Ensures that removal of a bookmark untags the bookmark if it's no longer
+ * contained in any regular, non-tag folders.  See bug 444849.
+ */
+
+var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+  Ci.nsINavHistoryService
+);
+
+var tagssvc = Cc["@mozilla.org/browser/tagging-service;1"].getService(
+  Ci.nsITaggingService
+);
+
+const BOOKMARK_URI = uri("http://example.com/");
+
+add_task(async function test_removing_tagged_bookmark_removes_tag() {
+  print("  Make a bookmark.");
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: BOOKMARK_URI,
+    title: "test bookmark",
+  });
+
+  print("  Tag it up.");
+  let tags = ["foo", "bar"];
+  tagssvc.tagURI(BOOKMARK_URI, tags);
+  ensureTagsExist(tags);
+  let root = getTagRoot();
+  root.containerOpen = true;
+  let oldCount = root.childCount;
+  root.containerOpen = false;
+
+  print("  Remove the bookmark.  The tags should no longer exist.");
+  let wait = TestUtils.waitForCondition(() => {
+    root = getTagRoot();
+    root.containerOpen = true;
+    let val = root.childCount == oldCount - 2;
+    root.containerOpen = false;
+    return val;
+  });
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+  await wait;
+  ensureTagsExist([]);
+});
+
+add_task(
+  async function test_removing_folder_containing_tagged_bookmark_removes_tag() {
+    print("  Make a folder.");
+    let folder = await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      title: "test folder",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+
+    print("  Stick a bookmark in the folder.");
+    var bookmark = await PlacesUtils.bookmarks.insert({
+      parentGuid: folder.guid,
+      url: BOOKMARK_URI,
+      title: "test bookmark",
+    });
+
+    print("  Tag the bookmark.");
+    var tags = ["foo", "bar"];
+    tagssvc.tagURI(BOOKMARK_URI, tags);
+    ensureTagsExist(tags);
+
+    // The tag containers are removed in async and take some time
+    let oldCountFoo = await tagCount("foo");
+    let oldCountBar = await tagCount("bar");
+
+    print("  Remove the folder.  The tags should no longer exist.");
+
+    let wait = TestUtils.waitForCondition(async () => {
+      let newCountFoo = await tagCount("foo");
+      let newCountBar = await tagCount("bar");
+      return newCountFoo == oldCountFoo - 1 && newCountBar == oldCountBar - 1;
+    });
+    await PlacesUtils.bookmarks.remove(bookmark.guid);
+    await wait;
+    ensureTagsExist([]);
+  }
+);
+
+async function tagCount(aTag) {
+  let allTags = await PlacesUtils.bookmarks.fetchTags();
+  for (let i of allTags) {
+    if (i.name == aTag) {
+      return i.count;
+    }
+  }
+  return 0;
+}
+
+function getTagRoot() {
+  var query = histsvc.getNewQuery();
+  var opts = histsvc.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_TAGS_ROOT;
+  var resultRoot = histsvc.executeQuery(query, opts).root;
+  return resultRoot;
+}
+/**
+ * Runs a tag query and ensures that the tags returned are those and only those
+ * in aTags.  aTags may be empty, in which case this function ensures that no
+ * tags exist.
+ *
+ * @param aTags
+ *        An array of tags (strings)
+ */
+function ensureTagsExist(aTags) {
+  var query = histsvc.getNewQuery();
+  var opts = histsvc.getNewQueryOptions();
+  opts.resultType = opts.RESULTS_AS_TAGS_ROOT;
+  var resultRoot = histsvc.executeQuery(query, opts).root;
+
+  // Dupe aTags.
+  var tags = aTags.slice(0);
+
+  resultRoot.containerOpen = true;
+
+  // Ensure that the number of tags returned from the query is the same as the
+  // number in |tags|.
+  Assert.equal(resultRoot.childCount, tags.length);
+
+  // For each tag result from the query, ensure that it's contained in |tags|.
+  // Remove the tag from |tags| so that we ensure the sets are equal.
+  for (let i = 0; i < resultRoot.childCount; i++) {
+    var tag = resultRoot.getChild(i).title;
+    var indexOfTag = tags.indexOf(tag);
+    Assert.ok(indexOfTag >= 0);
+    tags.splice(indexOfTag, 1);
+  }
+
+  resultRoot.containerOpen = false;
+}
diff --git a/toolkit/components/places/tests/unit/test_frecency_decay.js b/toolkit/components/places/tests/unit/test_frecency_decay.js
new file mode 100644
index 0000000000..8fbb08aecc
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_decay.js
@@ -0,0 +1,82 @@
+/* Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/ */
+
+const PREF_FREC_DECAY_RATE_DEF = 0.975;
+
+/**
+ * Promises that the pages-rank-changed event has been seen.
+ *
+ * @returns {Promise} A promise which is resolved when the notification is seen.
+ */
+function promiseRankingChanged() {
+  return PlacesTestUtils.waitForNotification("pages-rank-changed");
+}
+
+add_task(async function setup() {
+  Services.prefs.setCharPref(
+    "places.frecency.decayRate",
+    PREF_FREC_DECAY_RATE_DEF
+  );
+});
+
+add_task(async function test_isFrecencyDecaying() {
+  let db = await PlacesUtils.promiseDBConnection();
+  async function queryFrecencyDecaying() {
+    return (
+      await db.executeCached(`SELECT is_frecency_decaying()`)
+    )[0].getResultByIndex(0);
+  }
+  PlacesUtils.history.isFrecencyDecaying = true;
+  Assert.equal(PlacesUtils.history.isFrecencyDecaying, true);
+  Assert.equal(await queryFrecencyDecaying(), true);
+  PlacesUtils.history.isFrecencyDecaying = false;
+  Assert.equal(PlacesUtils.history.isFrecencyDecaying, false);
+  Assert.equal(await queryFrecencyDecaying(), false);
+});
+
+add_task(async function test_frecency_decay() {
+  let unvisitedBookmarkFrecency = Services.prefs.getIntPref(
+    "places.frecency.unvisitedBookmarkBonus"
+  );
+
+  // Add a bookmark and check its frecency.
+  let url = "http://example.com/b";
+  let promiseOne = promiseRankingChanged();
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promiseOne;
+
+  let histogram = TelemetryTestUtils.getAndClearHistogram(
+    "PLACES_IDLE_FRECENCY_DECAY_TIME_MS"
+  );
+  info("Trigger frecency decay.");
+  Assert.equal(PlacesUtils.history.isFrecencyDecaying, false);
+  let promiseRanking = promiseRankingChanged();
+
+  PlacesFrecencyRecalculator.observe(null, "idle-daily", "");
+  Assert.equal(PlacesUtils.history.isFrecencyDecaying, true);
+  info("Wait for completion.");
+  await PlacesFrecencyRecalculator.pendingFrecencyDecayPromise;
+
+  await promiseRanking;
+  Assert.equal(PlacesUtils.history.isFrecencyDecaying, false);
+
+  // Now check the new frecency is correct.
+  let newFrecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    { url }
+  );
+
+  Assert.equal(
+    newFrecency,
+    Math.round(unvisitedBookmarkFrecency * PREF_FREC_DECAY_RATE_DEF),
+    "Frecencies should match"
+  );
+
+  let snapshot = histogram.snapshot();
+  Assert.greater(snapshot.sum, 0);
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_observers.js b/toolkit/components/places/tests/unit/test_frecency_observers.js
new file mode 100644
index 0000000000..44747b06f9
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_observers.js
@@ -0,0 +1,99 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Each of these tests a path that triggers a frecency update.  Together they
+// hit all sites that update a frecency.
+
+// InsertVisitedURIs::UpdateFrecency and History::InsertPlace
+add_task(
+  async function test_InsertVisitedURIs_UpdateFrecency_and_History_InsertPlace() {
+    // InsertPlace is at the end of a path that UpdateFrecency is also on, so kill
+    // two birds with one stone and expect two notifications.  Trigger the path by
+    // adding a download.
+    let url = Services.io.newURI("http://example.com/a");
+    let promise = onRankingChanged();
+    await PlacesUtils.history.insert({
+      url,
+      visits: [
+        {
+          transition: PlacesUtils.history.TRANSITIONS.DOWNLOAD,
+        },
+      ],
+    });
+    await promise;
+  }
+);
+
+// nsNavHistory::UpdateFrecency
+add_task(async function test_nsNavHistory_UpdateFrecency() {
+  let url = Services.io.newURI("http://example.com/b");
+  let promise = onRankingChanged();
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url,
+    title: "test",
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+});
+
+// History.jsm invalidateFrecencies()
+add_task(async function test_invalidateFrecencies() {
+  let url = Services.io.newURI("http://test-invalidateFrecencies.com/");
+  // Bookmarking the URI is enough to add it to moz_places, and importantly, it
+  // means that removeByFilter doesn't remove it from moz_places, so its
+  // frecency is able to be changed.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url,
+    title: "test",
+  });
+  let promise = onRankingChanged();
+  await PlacesUtils.history.removeByFilter({ host: url.host });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  await promise;
+});
+
+// History.jsm clear() should not cause a frecency recalculation since pages
+// are removed.
+add_task(async function test_clear() {
+  let received = [];
+  let listener = events =>
+    (received = received.concat(events.map(e => e.type)));
+  PlacesObservers.addListener(
+    ["history-cleared", "pages-rank-changed"],
+    listener
+  );
+  await PlacesUtils.history.clear();
+  PlacesObservers.removeListener(
+    ["history-cleared", "pages-rank-changed"],
+    listener
+  );
+  Assert.deepEqual(received, ["history-cleared"]);
+});
+
+add_task(async function test_nsNavHistory_idleDaily() {
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "https://test-site1.org",
+    title: "test",
+  });
+  PlacesFrecencyRecalculator.observe(null, "idle-daily", "");
+  await Promise.all([onRankingChanged()]);
+});
+
+add_task(async function test_nsNavHistory_recalculate() {
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "https://test-site1.org",
+    title: "test",
+  });
+  await Promise.all([
+    onRankingChanged(),
+    PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies(),
+  ]);
+});
+
+function onRankingChanged() {
+  return PlacesTestUtils.waitForNotification("pages-rank-changed");
+}
diff --git a/toolkit/components/places/tests/unit/test_frecency_origins_alternative.js b/toolkit/components/places/tests/unit/test_frecency_origins_alternative.js
new file mode 100644
index 0000000000..5519149cac
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_origins_alternative.js
@@ -0,0 +1,301 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests alternative origins frecency.
+// Note: the order of the tests here matters, since we are emulating subsquent
+// starts of the recalculator component with different initial conditions.
+
+const FEATURE_PREF = "places.frecency.origins.alternative.featureGate";
+
+async function restartRecalculator() {
+  let subject = {};
+  PlacesFrecencyRecalculator.observe(
+    subject,
+    "test-alternative-frecency-init",
+    ""
+  );
+  await subject.promise;
+}
+
+async function getAllOrigins() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`SELECT * FROM moz_origins`);
+  Assert.greater(rows.length, 0);
+  return rows.map(r => ({
+    host: r.getResultByName("host"),
+    frecency: r.getResultByName("frecency"),
+    recalc_frecency: r.getResultByName("recalc_frecency"),
+    alt_frecency: r.getResultByName("alt_frecency"),
+    recalc_alt_frecency: r.getResultByName("recalc_alt_frecency"),
+  }));
+}
+
+add_setup(async function () {
+  await PlacesTestUtils.addVisits([
+    "https://testdomain1.moz.org",
+    "https://testdomain2.moz.org",
+    "https://testdomain3.moz.org",
+  ]);
+  registerCleanupFunction(PlacesUtils.history.clear);
+});
+
+add_task(async function test_normal_init() {
+  // Ensure moz_meta doesn't report anything.
+  Assert.ok(
+    !PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.enabled,
+    "Check the pref is disabled by default"
+  );
+  // Avoid hitting the cache, we want to check the actual database value.
+  PlacesUtils.metadata.cache.clear();
+  Assert.ok(
+    ObjectUtils.isEmpty(
+      await PlacesUtils.metadata.get(
+        PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+        Object.create(null)
+      )
+    ),
+    "Check there's no variables stored"
+  );
+});
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_enable_init() {
+    // Set alt_frecency to NULL and recalc_alt_frecency = 0 for the entries in
+    // moz_origins to verify they are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_origins", {
+      alt_frecency: null,
+      recalc_alt_frecency: 0,
+    });
+
+    await restartRecalculator();
+
+    // Ensure moz_meta doesn't report anything.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.equal(
+      (
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins
+            .metadataKey,
+          Object.create(null)
+        )
+      ).version,
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.variables
+        .version,
+      "Check the algorithm version has been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    let origins = await getAllOrigins();
+    Assert.ok(
+      origins.every(o => o.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      origins.every(o => o.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_different_version() {
+    let origins = await getAllOrigins();
+    Assert.ok(
+      origins.every(o => o.recalc_alt_frecency == 0),
+      "All the entries should not need recalculation"
+    );
+
+    // Set alt_frecency to NULL for the entries in moz_origins to verify they
+    // are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_origins", {
+      alt_frecency: null,
+    });
+
+    // It doesn't matter that the version is, it just have to be different.
+    let variables = await PlacesUtils.metadata.get(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+      Object.create(null)
+    );
+    variables.version = 999;
+    await PlacesUtils.metadata.set(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+      variables
+    );
+
+    await restartRecalculator();
+
+    // Check alternative frecency has been marked for recalculation.
+    // Note just after init we reculate a chunk, and this test code is expected
+    // to run before that... though we can't be sure, so if this starts failing
+    // intermittently we'll have to add more synchronization test code.
+    origins = await getAllOrigins();
+    // Ensure moz_meta has been updated.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.deepEqual(
+      (
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins
+            .metadataKey,
+          Object.create(null)
+        )
+      ).version,
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.variables
+        .version,
+      "Check the algorithm version has been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    origins = await getAllOrigins();
+    Assert.ok(
+      origins.every(o => o.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      origins.every(o => o.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_different_variables() {
+    let origins = await getAllOrigins();
+    Assert.ok(
+      origins.every(o => o.recalc_alt_frecency == 0),
+      "All the entries should not need recalculation"
+    );
+
+    // Set alt_frecency to NULL for the entries in moz_origins to verify they
+    // are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_origins", {
+      alt_frecency: null,
+    });
+
+    // Change variables.
+    let variables = await PlacesUtils.metadata.get(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+      Object.create(null)
+    );
+    Assert.greater(Object.keys(variables).length, 1);
+    Assert.ok("version" in variables, "At least the version is always present");
+    await PlacesUtils.metadata.set(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+      {
+        version:
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.variables
+            .version,
+        someVar: 1,
+      }
+    );
+
+    await restartRecalculator();
+
+    // Ensure moz_meta has been updated.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.deepEqual(
+      await PlacesUtils.metadata.get(
+        PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+        Object.create(null)
+      ),
+      variables,
+      "Check the algorithm variables have been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    origins = await getAllOrigins();
+    Assert.ok(
+      origins.every(o => o.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      origins.every(o => o.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(async function test_disable() {
+  let origins = await getAllOrigins();
+  Assert.ok(
+    origins.every(o => o.recalc_alt_frecency == 0),
+    "All the entries should not need recalculation"
+  );
+  // Avoid hitting the cache, we want to check the actual database value.
+  PlacesUtils.metadata.cache.clear();
+  Assert.equal(
+    (
+      await PlacesUtils.metadata.get(
+        PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+        Object.create(null)
+      )
+    ).version,
+    PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.variables
+      .version,
+    "Check the algorithm version has been stored"
+  );
+
+  await restartRecalculator();
+
+  // Check alternative frecency has not been marked for recalculation.
+  origins = await getAllOrigins();
+  Assert.ok(
+    origins.every(o => o.recalc_alt_frecency == 0),
+    "The entries not have been marked for recalc"
+  );
+  Assert.ok(
+    origins.every(o => o.alt_frecency === null),
+    "All the alt_frecency values should have been nullified"
+  );
+
+  // Ensure moz_meta has been updated.
+  // Avoid hitting the cache, we want to check the actual database value.
+  PlacesUtils.metadata.cache.clear();
+  Assert.ok(
+    ObjectUtils.isEmpty(
+      await PlacesUtils.metadata.get(
+        PlacesFrecencyRecalculator.alternativeFrecencyInfo.origins.metadataKey,
+        Object.create(null)
+      )
+    ),
+    "Check the algorithm variables has been removed"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_origins_recalc.js b/toolkit/components/places/tests/unit/test_frecency_origins_recalc.js
new file mode 100644
index 0000000000..3a93912f13
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_origins_recalc.js
@@ -0,0 +1,109 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that recalc_frecency in the moz_origins table works is consistent.
+
+add_task(async function test() {
+  // test recalc_frecency is set to 1 when frecency of a page changes.
+  // Add a couple visits, then remove one of them.
+  const now = new Date();
+  const host = "mozilla.org";
+  const url = `https://${host}/test/`;
+  await PlacesTestUtils.addVisits([
+    {
+      url,
+      visitDate: now,
+    },
+    {
+      url,
+      visitDate: new Date(new Date().setDate(now.getDate() - 30)),
+    },
+  ]);
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_origins", "recalc_frecency", {
+      host,
+    }),
+    1,
+    "Frecency should be calculated"
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue(
+      "moz_origins",
+      "recalc_alt_frecency",
+      {
+        host,
+      }
+    ),
+    1,
+    "Alt frecency should be calculated"
+  );
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  let alt_frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_origins",
+    "alt_frecency",
+    { host }
+  );
+  let frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_origins",
+    "frecency",
+    { host }
+  );
+  // Remove only one visit (otherwise the page would be orphaned).
+  await PlacesUtils.history.removeVisitsByFilter({
+    beginDate: new Date(now.valueOf() - 10000),
+    endDate: new Date(now.valueOf() + 10000),
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_origins", "recalc_frecency", {
+      host,
+    }),
+    0,
+    "Should have been calculated"
+  );
+  Assert.greater(
+    frecency,
+    await PlacesTestUtils.getDatabaseValue("moz_origins", "frecency", {
+      host,
+    }),
+    "frecency should have decreased"
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue(
+      "moz_origins",
+      "recalc_alt_frecency",
+      { host }
+    ),
+    0,
+    "Should have been calculated"
+  );
+  Assert.greater(
+    alt_frecency,
+    await PlacesTestUtils.getDatabaseValue("moz_origins", "alt_frecency", {
+      host,
+    }),
+    "alternative frecency should have decreased"
+  );
+
+  // Add another page to the same host.
+  const url2 = `https://${host}/second/`;
+  await PlacesTestUtils.addVisits(url2);
+  // Remove the first page.
+  await PlacesUtils.history.remove(url);
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_origins", "recalc_frecency", {
+      host,
+    }),
+    1,
+    "Frecency should be calculated"
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue(
+      "moz_origins",
+      "recalc_alt_frecency",
+      { host }
+    ),
+    1,
+    "Alt frecency should be calculated"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_pages_alternative.js b/toolkit/components/places/tests/unit/test_frecency_pages_alternative.js
new file mode 100644
index 0000000000..0ea271c698
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_pages_alternative.js
@@ -0,0 +1,364 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests alternative pages frecency.
+// Note: the order of the tests here matters, since we are emulating subsquent
+// starts of the recalculator component with different initial conditions.
+
+const FEATURE_PREF = "places.frecency.pages.alternative.featureGate";
+
+async function restartRecalculator() {
+  let subject = {};
+  PlacesFrecencyRecalculator.observe(
+    subject,
+    "test-alternative-frecency-init",
+    ""
+  );
+  await subject.promise;
+}
+
+async function getAllPages() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`SELECT * FROM moz_places`);
+  Assert.greater(rows.length, 0);
+  return rows.map(r => ({
+    url: r.getResultByName("url"),
+    frecency: r.getResultByName("frecency"),
+    recalc_frecency: r.getResultByName("recalc_frecency"),
+    alt_frecency: r.getResultByName("alt_frecency"),
+    recalc_alt_frecency: r.getResultByName("recalc_alt_frecency"),
+  }));
+}
+
+add_setup(async function () {
+  await PlacesTestUtils.addVisits([
+    "https://testdomain1.moz.org",
+    "https://testdomain2.moz.org",
+    "https://testdomain3.moz.org",
+  ]);
+  registerCleanupFunction(PlacesUtils.history.clear);
+});
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, false]],
+  },
+  async function test_normal_init() {
+    // The test starts with the pref enabled, otherwise we'd not have the SQL
+    // function defined. So here we disable it, then enable again later.
+    await restartRecalculator();
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.ok(
+      ObjectUtils.isEmpty(
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+          Object.create(null)
+        )
+      ),
+      "Check there's no variables stored"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_enable_init() {
+    // Set alt_frecency to NULL and recalc_alt_frecency = 0 for the entries in
+    // moz_places to verify they are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_places", {
+      alt_frecency: null,
+      recalc_alt_frecency: 0,
+    });
+
+    await restartRecalculator();
+
+    // Ensure moz_meta doesn't report anything.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.equal(
+      (
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+          Object.create(null)
+        )
+      ).version,
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.variables
+        .version,
+      "Check the algorithm version has been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    let pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      pages.every(p => p.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_different_version() {
+    let pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries should not need recalculation"
+    );
+
+    // Set alt_frecency to NULL to verify all the entries are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_places", {
+      alt_frecency: null,
+    });
+
+    // It doesn't matter that the version is, it just have to be different.
+    let variables = await PlacesUtils.metadata.get(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+      Object.create(null)
+    );
+    variables.version = 999;
+    await PlacesUtils.metadata.set(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+      variables
+    );
+
+    await restartRecalculator();
+
+    // Check alternative frecency has been marked for recalculation.
+    // Note just after init we reculate a chunk, and this test code is expected
+    // to run before that... though we can't be sure, so if this starts failing
+    // intermittently we'll have to add more synchronization test code.
+    pages = await getAllPages();
+    // Ensure moz_meta has been updated.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.deepEqual(
+      (
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+          Object.create(null)
+        )
+      ).version,
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.variables
+        .version,
+      "Check the algorithm version has been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      pages.every(p => p.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_different_variables() {
+    let pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries should not need recalculation"
+    );
+
+    // Set alt_frecency to NULL to verify all the entries are recalculated.
+    await PlacesTestUtils.updateDatabaseValues("moz_places", {
+      alt_frecency: null,
+    });
+
+    // Change variables.
+    let variables = await PlacesUtils.metadata.get(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+      Object.create(null)
+    );
+    Assert.greater(Object.keys(variables).length, 1);
+    Assert.ok("version" in variables, "At least the version is always present");
+    await PlacesUtils.metadata.set(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+      {
+        version:
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.variables
+            .version,
+        someVar: 1,
+      }
+    );
+
+    await restartRecalculator();
+
+    // Ensure moz_meta has been updated.
+    Assert.ok(
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.enabled,
+      "Check the pref is enabled"
+    );
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.deepEqual(
+      await PlacesUtils.metadata.get(
+        PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+        Object.create(null)
+      ),
+      variables,
+      "Check the algorithm variables have been stored"
+    );
+
+    // Check all alternative frecencies have been calculated, since we just have
+    // a few.
+    pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      pages.every(p => p.alt_frecency > 0),
+      "All the entries have been recalculated"
+    );
+    Assert.ok(
+      PlacesFrecencyRecalculator.isRecalculationPending,
+      "Recalculation should be pending"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, false]],
+  },
+  async function test_disable() {
+    let pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "All the entries should not need recalculation"
+    );
+
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.equal(
+      (
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+          Object.create(null)
+        )
+      ).version,
+      PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.variables
+        .version,
+      "Check the algorithm version has been stored"
+    );
+
+    await restartRecalculator();
+
+    // Check alternative frecency has not been marked for recalculation.
+    pages = await getAllPages();
+    Assert.ok(
+      pages.every(p => p.recalc_alt_frecency == 0),
+      "The entries not have been marked for recalc"
+    );
+    Assert.ok(
+      pages.every(p => p.alt_frecency === null),
+      "All the alt_frecency values should have been nullified"
+    );
+
+    // Ensure moz_meta has been updated.
+    // Avoid hitting the cache, we want to check the actual database value.
+    PlacesUtils.metadata.cache.clear();
+    Assert.ok(
+      ObjectUtils.isEmpty(
+        await PlacesUtils.metadata.get(
+          PlacesFrecencyRecalculator.alternativeFrecencyInfo.pages.metadataKey,
+          Object.create(null)
+        )
+      ),
+      "Check the algorithm variables has been removed"
+    );
+  }
+);
+
+add_task(
+  {
+    pref_set: [[FEATURE_PREF, true]],
+  },
+  async function test_score() {
+    await restartRecalculator();
+
+    // This is not intended to cover the algorithm as a whole, but just as a
+    // sanity check for scores.
+
+    // Add before visits to properly set visit source.
+    await PlacesUtils.bookmarks.insert({
+      url: "https://visitedbookmark.moz.org",
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    });
+
+    await PlacesTestUtils.addVisits([
+      {
+        url: "https://low.moz.org",
+        transition: PlacesUtils.history.TRANSITIONS.FRAMED_LINK,
+      },
+      {
+        url: "https://visitedbookmark.moz.org",
+        transition: PlacesUtils.history.TRANSITIONS.FRAMED_LINK,
+      },
+      {
+        url: "https://old.moz.org",
+        visitDate: (Date.now() - 2 * 86400000) * 1000,
+      },
+      { url: "https://base.moz.org" },
+      { url: "https://manyvisits.moz.org" },
+      { url: "https://manyvisits.moz.org" },
+      { url: "https://manyvisits.moz.org" },
+      { url: "https://manyvisits.moz.org" },
+    ]);
+    await PlacesUtils.bookmarks.insert({
+      url: "https://unvisitedbookmark.moz.org",
+      parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    });
+    await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+    let getFrecency = url =>
+      PlacesTestUtils.getDatabaseValue("moz_places", "alt_frecency", {
+        url,
+      });
+    let low = await getFrecency("https://low.moz.org/");
+    let old = await getFrecency("https://old.moz.org/");
+    Assert.greater(old, low);
+    let base = await getFrecency("https://base.moz.org/");
+    Assert.greater(base, old);
+    let unvisitedBm = await getFrecency("https://unvisitedbookmark.moz.org/");
+    Assert.greater(unvisitedBm, base);
+    let manyVisits = await getFrecency("https://manyvisits.moz.org/");
+    Assert.greater(manyVisits, unvisitedBm);
+    let visitedBm = await getFrecency("https://visitedbookmark.moz.org/");
+    Assert.greater(visitedBm, base);
+  }
+);
diff --git a/toolkit/components/places/tests/unit/test_frecency_pages_recalc_alt.js b/toolkit/components/places/tests/unit/test_frecency_pages_recalc_alt.js
new file mode 100644
index 0000000000..9642e87ad2
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_pages_recalc_alt.js
@@ -0,0 +1,97 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that recalc_alt_frecency in the moz_places table is updated correctly.
+
+add_task(async function test() {
+  // Start from a stable situation, otherwise the recalculator may set recalc
+  // field at any time due to the initialization.
+  let subject = {};
+  PlacesFrecencyRecalculator.observe(
+    subject,
+    "test-alternative-frecency-init",
+    ""
+  );
+  await subject.promise;
+
+  info("test recalc_alt_frecency is set to 1 when a visit is added");
+  const now = new Date();
+  const URL = "https://mozilla.org/test/";
+  let getRecalc = url =>
+    PlacesTestUtils.getDatabaseValue("moz_places", "recalc_alt_frecency", {
+      url,
+    });
+  let setRecalc = (url, val) =>
+    PlacesTestUtils.updateDatabaseValues(
+      "moz_places",
+      { recalc_alt_frecency: val },
+      { url }
+    );
+  let getFrecency = url =>
+    PlacesTestUtils.getDatabaseValue("moz_places", "alt_frecency", {
+      url,
+    });
+  await PlacesTestUtils.addVisits([
+    {
+      url: URL,
+      visitDate: now,
+    },
+    {
+      url: URL,
+      visitDate: new Date(new Date().setDate(now.getDate() - 30)),
+    },
+  ]);
+  // The frecency has been recalculated by addVisits already, checking that
+  // alt frecency has a positive value should be sufficient anyway.
+  Assert.equal(await getRecalc(URL), 0);
+  Assert.greater(await getFrecency(URL), 0);
+
+  info("Remove just one visit (otherwise the page would be orphaned).");
+  await PlacesUtils.history.removeVisitsByFilter({
+    beginDate: new Date(now.valueOf() - 10000),
+    endDate: new Date(now.valueOf() + 10000),
+  });
+  Assert.equal(await getRecalc(URL), 1);
+  await setRecalc(URL, 0);
+
+  info("Add a bookmark to the page");
+  let bm = await PlacesUtils.bookmarks.insert({
+    url: URL,
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  Assert.equal(await getRecalc(URL), 1);
+  await setRecalc(URL, 0);
+
+  info("Clear history");
+  await PlacesUtils.history.clear();
+  Assert.equal(await getRecalc(URL), 1);
+  await setRecalc(URL, 0);
+
+  // Add back a visit so the page is not an orphan once we remove the bookmark.
+  await PlacesTestUtils.addVisits(URL);
+  Assert.equal(await getRecalc(URL), 0);
+  Assert.greater(await getFrecency(URL), 0);
+
+  info("change the bookmark URL");
+  const URL2 = "https://editedbookmark.org/";
+  bm.url = URL2;
+  await PlacesUtils.bookmarks.update(bm);
+  Assert.equal(await getRecalc(URL), 1);
+  Assert.equal(await getRecalc(URL2), 1);
+  await setRecalc(URL, 0);
+  await setRecalc(URL2, 0);
+
+  info("Remove the bookmark from the page");
+  await PlacesUtils.bookmarks.remove(bm);
+  Assert.equal(await getRecalc(URL2), 1);
+  await setRecalc(URL2, 0);
+
+  const URL3 = "https://test3.moz.org/";
+  const URL4 = "https://test4.moz.org/";
+  info("Insert multiple pages now");
+  await PlacesTestUtils.addVisits([URL3, URL4]);
+  Assert.equal(await getRecalc(URL3), 0);
+  Assert.greater(await getFrecency(URL3), 0);
+  Assert.equal(await getRecalc(URL4), 0);
+  Assert.greater(await getFrecency(URL4), 0);
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_recalc_triggers.js b/toolkit/components/places/tests/unit/test_frecency_recalc_triggers.js
new file mode 100644
index 0000000000..2e75a6d459
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_recalc_triggers.js
@@ -0,0 +1,281 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that all the operations affecting frecency are either recalculating
+ * immediately or triggering a recalculation.
+ * Operations that should recalculate immediately:
+ *  - adding visits
+ * Operations that should just trigger a recalculation:
+ *  - removing visits
+ *  - adding a bookmark
+ *  - removing a bookmark
+ *  - changing url of a bookmark
+ *
+ * Also check setting a frecency resets recalc_frecency to 0.
+ **/
+
+const TEST_URL = "https://example.com/";
+const TEST_URL_2 = "https://example2.com/";
+
+// NOTE: Until we fix Bug 1806666 this test has to run queries manually because
+// the official APIs recalculate frecency immediately. After the fix, these
+// helpers can be removed and the test can be much simpler.
+function insertVisit(url) {
+  return PlacesUtils.withConnectionWrapper("insertVisit", async db => {
+    await db.execute(
+      `INSERT INTO moz_historyvisits(place_id, visit_date, visit_type)
+       VALUES ((SELECT id FROM moz_places WHERE url = :url), 1648226608386000, 1)`,
+      { url }
+    );
+  });
+}
+function removeVisit(url) {
+  return PlacesUtils.withConnectionWrapper("insertVisit", async db => {
+    await db.execute(
+      `DELETE FROM moz_historyvisits WHERE place_id
+        = (SELECT id FROM moz_places WHERE url = :url)`,
+      { url }
+    );
+  });
+}
+function resetFrecency(url) {
+  return PlacesUtils.withConnectionWrapper("insertVisit", async db => {
+    await db.execute(`UPDATE moz_places SET frecency = -1 WHERE url = :url`, {
+      url,
+    });
+  });
+}
+
+add_task(async function test_visit() {
+  // First add a bookmark so the page is not orphaned.
+  let bm = await PlacesUtils.bookmarks.insert({
+    url: TEST_URL,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+
+  info("Add a visit check frecency is calculated immediately");
+  await PlacesTestUtils.addVisits(TEST_URL);
+  let originalFrecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.greater(originalFrecency, 0, "frecency was recalculated immediately");
+  let recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 0, "frecency doesn't need a recalc");
+
+  info("Add a visit (raw query) check frecency is not calculated immediately");
+  await insertVisit(TEST_URL);
+  let frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(frecency, originalFrecency, "frecency is unchanged");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+
+  info("Check setting frecency resets recalc_frecency");
+  await resetFrecency(TEST_URL);
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 0, "frecency doesn't need a recalc");
+
+  info("Removing a visit sets recalc_frecency");
+  await removeVisit(TEST_URL);
+  frecency = await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+    url: TEST_URL,
+  });
+  Assert.equal(frecency, -1, "frecency is unchanged");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.remove(bm);
+});
+
+add_task(async function test_bookmark() {
+  // First add a visit so the page is not orphaned.
+  await PlacesTestUtils.addVisits([TEST_URL, TEST_URL_2]);
+
+  let originalFrecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.greater(originalFrecency, 0);
+
+  info("Check adding a bookmark sets recalc_frecency");
+  let bm = await PlacesUtils.bookmarks.insert({
+    url: TEST_URL,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+
+  let frecency = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(frecency, originalFrecency, "frecency is unchanged");
+  let recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+
+  info("Check changing a bookmark url sets recalc_frecency on both urls");
+  await PlacesUtils.bookmarks.update({
+    guid: bm.guid,
+    url: TEST_URL_2,
+  });
+  frecency = await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+    url: TEST_URL,
+  });
+  Assert.equal(frecency, originalFrecency, "frecency is unchanged");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+  frecency = await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+    url: TEST_URL_2,
+  });
+  Assert.ok(frecency > 0, "frecency is valid");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL_2,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+
+  info("Check setting frecency resets recalc_frecency");
+  await resetFrecency(TEST_URL);
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 0, "frecency doesn't need a recalc");
+  await resetFrecency(TEST_URL_2);
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL_2,
+    }
+  );
+  Assert.equal(recalc, 0, "frecency doesn't need a recalc");
+
+  info("Removing a bookmark sets recalc_frecency");
+  await PlacesUtils.bookmarks.remove(bm.guid);
+  frecency = await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+    url: TEST_URL,
+  });
+  Assert.equal(frecency, -1, "frecency is unchanged");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL,
+    }
+  );
+  Assert.equal(recalc, 0, "frecency doesn't need a recalc");
+  frecency = await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+    url: TEST_URL_2,
+  });
+  Assert.equal(frecency, -1, "frecency is unchanged");
+  recalc = await PlacesTestUtils.getDatabaseValue(
+    "moz_places",
+    "recalc_frecency",
+    {
+      url: TEST_URL_2,
+    }
+  );
+  Assert.equal(recalc, 1, "frecency needs a recalc");
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_bookmark_frecency_zero() {
+  info("A url with frecency 0 should be recalculated if bookmarked");
+  let url = "https://zerofrecency.org/";
+  await PlacesTestUtils.addVisits({ url, transition: TRANSITION_FRAMED_LINK });
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", { url }),
+    0
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "recalc_frecency", {
+      url,
+    }),
+    0
+  );
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "recalc_frecency", {
+      url,
+    }),
+    1
+  );
+  info("place: uris should not be recalculated");
+  url = "place:test";
+  await PlacesUtils.bookmarks.insert({
+    url,
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", { url }),
+    0
+  );
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "recalc_frecency", {
+      url,
+    }),
+    0
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_recalculator.js b/toolkit/components/places/tests/unit/test_frecency_recalculator.js
new file mode 100644
index 0000000000..ed4501c56a
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_recalculator.js
@@ -0,0 +1,178 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test PlacesFrecencyRecalculator scheduling.
+
+// Enable the collection (during test) for all products so even products
+// that don't collect the data will be able to run the test without failure.
+Services.prefs.setBoolPref(
+  "toolkit.telemetry.testing.overrideProductsCheck",
+  true
+);
+
+async function getOriginFrecency(origin) {
+  let db = await PlacesUtils.promiseDBConnection();
+  return (
+    await db.execute(
+      `SELECT frecency
+       FROM moz_origins
+       WHERE host = :origin`,
+      { origin }
+    )
+  )[0].getResultByIndex(0);
+}
+
+async function resetOriginFrecency(origin) {
+  await PlacesUtils.withConnectionWrapper(
+    "test_frecency_recalculator reset origin",
+    async db => {
+      await db.executeCached(
+        `UPDATE moz_origins
+         SET frecency = -1
+         WHERE host = :origin`,
+        { origin }
+      );
+    }
+  );
+}
+
+async function addVisitsAndSetRecalc(urls) {
+  await PlacesTestUtils.addVisits(urls);
+  await PlacesUtils.withConnectionWrapper(
+    "test_frecency_recalculator set recalc",
+    async db => {
+      await db.executeCached(
+        `UPDATE moz_places
+         SET frecency = -1
+         WHERE url in (
+           ${PlacesUtils.sqlBindPlaceholders(urls)}
+         )`,
+        urls
+      );
+      await db.executeCached(
+        `UPDATE moz_places
+         SET recalc_frecency = (CASE WHEN url in (
+               ${PlacesUtils.sqlBindPlaceholders(urls)}
+             ) THEN 1 ELSE 0 END)`,
+        urls
+      );
+    }
+  );
+}
+
+add_task(async function test() {
+  info("On startup a recalculation is always pending.");
+  Assert.ok(
+    PlacesFrecencyRecalculator.isRecalculationPending,
+    "Recalculation should be pending"
+  );
+  // If everything gets recalculated, then it should not be pending anymore.
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.ok(
+    !PlacesFrecencyRecalculator.isRecalculationPending,
+    "Recalculation should not be pending"
+  );
+
+  // If after a recalculation there's outdated entries left, a new recalculation
+  // should be pending.
+  info("Insert outdated frecencies");
+  const url1 = new URL("https://test1.moz.org/");
+  const url2 = new URL("https://test2.moz.org/");
+  await addVisitsAndSetRecalc([url1.href, url2.href]);
+  await resetOriginFrecency(url1.host);
+  await resetOriginFrecency(url2.host);
+
+  Assert.ok(
+    PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have set shouldStartFrecencyRecalculation"
+  );
+  await PlacesFrecencyRecalculator.recalculateSomeFrecencies({ chunkSize: 1 });
+  Assert.ok(
+    PlacesFrecencyRecalculator.isRecalculationPending,
+    "Recalculation should be pending"
+  );
+  // Recalculating uri1 will set its origin to recalc, that means there's 2
+  // origins to recalc now. Passing chunkSize: 2 here would then retrigger the
+  // recalc, thinking we saturated the chunk, thus we use 3.
+  await PlacesFrecencyRecalculator.recalculateSomeFrecencies({ chunkSize: 3 });
+  Assert.ok(
+    !PlacesFrecencyRecalculator.isRecalculationPending,
+    "Recalculation should not be pending"
+  );
+  Assert.ok(
+    !PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have unset shouldStartFrecencyRecalculation"
+  );
+
+  Assert.greater(await getOriginFrecency(url1.host), 0);
+  Assert.greater(await getOriginFrecency(url2.host), 0);
+
+  info("Changing recalc_frecency of an entry adds a pending recalculation.");
+  PlacesUtils.history.shouldStartFrecencyRecalculation = false;
+  let promiseNotify = TestUtils.topicObserved("frecency-recalculation-needed");
+  await PlacesUtils.withConnectionWrapper(
+    "test_frecency_recalculator",
+    async db => {
+      await db.executeCached(
+        `UPDATE moz_places SET recalc_frecency = 1 WHERE url = :url`,
+        { url: url1.href }
+      );
+    }
+  );
+  Assert.ok(
+    PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have set shouldStartFrecencyRecalculation"
+  );
+
+  await promiseNotify;
+  Assert.ok(
+    PlacesFrecencyRecalculator.isRecalculationPending,
+    "Recalculation should be pending"
+  );
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.ok(
+    !PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have unset shouldStartFrecencyRecalculation"
+  );
+});
+
+add_task(async function test_chunk_time_telemetry() {
+  await PlacesUtils.bookmarks.insert({
+    url: "https://test-bookmark.com",
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+  });
+  Assert.ok(
+    PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have set shouldStartFrecencyRecalculation"
+  );
+  let histogram = TelemetryTestUtils.getAndClearHistogram(
+    "PLACES_FRECENCY_RECALC_CHUNK_TIME_MS"
+  );
+  let subject = {};
+  PlacesFrecencyRecalculator.observe(subject, "test-execute-taskFn", "");
+  await subject.promise;
+  let snapshot = histogram.snapshot();
+  Assert.equal(
+    Object.values(snapshot.values).reduce((a, b) => a + b, 0),
+    1
+  );
+  Assert.greater(snapshot.sum, 0);
+  Assert.ok(
+    !PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should have unset shouldStartFrecencyRecalculation"
+  );
+
+  // It should now not report any new time, since there's nothing to recalculate.
+  histogram.clear();
+  PlacesFrecencyRecalculator.observe(subject, "test-execute-taskFn", "");
+  await subject.promise;
+  snapshot = histogram.snapshot();
+  Assert.equal(
+    Object.values(snapshot.values).reduce((a, b) => a + b, 0),
+    0
+  );
+  Assert.ok(
+    !PlacesUtils.history.shouldStartFrecencyRecalculation,
+    "Should still not have set shouldStartFrecencyRecalculation"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_unvisited_bookmark.js b/toolkit/components/places/tests/unit/test_frecency_unvisited_bookmark.js
new file mode 100644
index 0000000000..ae7bd3d813
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_unvisited_bookmark.js
@@ -0,0 +1,54 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests frecency of unvisited bookmarks.
+
+add_task(async function () {
+  // Randomly sorted by date.
+  const now = new Date();
+  const bookmarks = [
+    {
+      url: "https://example.com/1",
+      date: new Date(new Date().setDate(now.getDate() - 30)),
+    },
+    {
+      url: "https://example.com/2",
+      date: new Date(new Date().setDate(now.getDate() - 1)),
+    },
+    {
+      url: "https://example.com/3",
+      date: new Date(new Date().setDate(now.getDate() - 100)),
+    },
+    {
+      url: "https://example.com/1", // Same url but much older.
+      date: new Date(new Date().setDate(now.getDate() - 120)),
+    },
+  ];
+
+  for (let bookmark of bookmarks) {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      url: bookmark.url,
+      dateAdded: bookmark.date,
+    });
+  }
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  // The newest bookmark should have an higher frecency.
+  Assert.greater(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: bookmarks[1].url,
+    }),
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: bookmarks[0].url,
+    })
+  );
+  Assert.greater(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: bookmarks[0].url,
+    }),
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: bookmarks[2].url,
+    })
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_frecency_zero_updated.js b/toolkit/components/places/tests/unit/test_frecency_zero_updated.js
new file mode 100644
index 0000000000..44c329635e
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_frecency_zero_updated.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests a zero frecency is correctly updated when inserting new valid visits.
+
+add_task(async function () {
+  const TEST_URI = NetUtil.newURI("http://example.com/");
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: TEST_URI,
+    title: "A title",
+  });
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+
+  // Removing the bookmark should leave an orphan page with zero frecency.
+  // Note this would usually be expired later by expiration.
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  // Now add a valid visit to the page, frecency should increase.
+  await PlacesTestUtils.addVisits({ uri: TEST_URI });
+  Assert.ok(
+    (await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    })) > 0
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_getChildIndex.js b/toolkit/components/places/tests/unit/test_getChildIndex.js
new file mode 100644
index 0000000000..35eb6fd22b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_getChildIndex.js
@@ -0,0 +1,73 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * vim:set ts=2 sw=2 sts=2 et:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Tests nsNavHistoryContainerResultNode::GetChildIndex(aNode) functionality.
+ */
+
+add_task(async function test_get_child_index() {
+  // Add a bookmark to the menu.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://test.mozilla.org/bookmark/",
+    title: "Test bookmark",
+  });
+
+  // Add a bookmark to unfiled folder.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://test.mozilla.org/unfiled/",
+    title: "Unfiled bookmark",
+  });
+
+  // Get the unfiled bookmark node.
+  let unfiledNode = getNodeAt(PlacesUtils.bookmarks.unfiledGuid, 0);
+  if (!unfiledNode) {
+    do_throw("Unable to find bookmark in hierarchy!");
+  }
+  Assert.equal(unfiledNode.title, "Unfiled bookmark");
+
+  let hs = PlacesUtils.history;
+  let query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.menuGuid]);
+  let options = hs.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let root = hs.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  // Check functionality for proper nodes.
+  for (let i = 0; i < root.childCount; i++) {
+    let node = root.getChild(i);
+    print("Now testing: " + node.title);
+    Assert.equal(root.getChildIndex(node), i);
+  }
+
+  // Now search for an invalid node and expect an exception.
+  try {
+    root.getChildIndex(unfiledNode);
+    do_throw("Searching for an invalid node should have thrown.");
+  } catch (ex) {
+    print("We correctly got an exception.");
+  }
+
+  root.containerOpen = false;
+});
+
+function getNodeAt(aFolderGuid, aIndex) {
+  let hs = PlacesUtils.history;
+  let query = hs.getNewQuery();
+  query.setParents([aFolderGuid]);
+  let options = hs.getNewQueryOptions();
+  options.queryType = options.QUERY_TYPE_BOOKMARKS;
+  let root = hs.executeQuery(query, options).root;
+  root.containerOpen = true;
+  if (root.childCount < aIndex) {
+    do_throw("Not enough children to find bookmark!");
+  }
+  let node = root.getChild(aIndex);
+  root.containerOpen = false;
+  return node;
+}
diff --git a/toolkit/components/places/tests/unit/test_get_query_param_sql_function.js b/toolkit/components/places/tests/unit/test_get_query_param_sql_function.js
new file mode 100644
index 0000000000..072f53ceac
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_get_query_param_sql_function.js
@@ -0,0 +1,21 @@
+add_task(async function test_get_query_param_sql_function() {
+  let db = await PlacesUtils.promiseDBConnection();
+  await Assert.rejects(
+    db.execute(`SELECT get_query_param()`),
+    /wrong number of arguments/
+  );
+  let rows = await db.execute(`SELECT
+    get_query_param('a=b&c=d', 'a'),
+    get_query_param('a=b&c=d', 'c'),
+    get_query_param('a=b&a=c', 'a'),
+    get_query_param('a=b&c=d', 'e'),
+    get_query_param('a', 'a'),
+    get_query_param(NULL, NULL),
+    get_query_param('a=b&c=d', NULL),
+    get_query_param(NULL, 'a')`);
+  let results = ["b", "d", "b", null, "", null, null, null];
+  equal(rows[0].numEntries, results.length);
+  for (let i = 0; i < results.length; ++i) {
+    equal(rows[0].getResultByIndex(i), results[i]);
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_hash.js b/toolkit/components/places/tests/unit/test_hash.js
new file mode 100644
index 0000000000..701cb3d151
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_hash.js
@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function () {
+  // Check particular unicode urls with insertion and selection APIs to ensure
+  // url hashes match properly.
+  const URLS = [
+    "http://президент.президент/президент/",
+    "https://www.аррӏе.com/аррӏе/",
+    "http://名がドメイン/",
+  ];
+
+  for (let url of URLS) {
+    await PlacesTestUtils.addVisits(url);
+    Assert.ok(await PlacesUtils.history.fetch(url), "Found the added visit");
+    await PlacesUtils.bookmarks.insert({
+      url,
+      parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    });
+    Assert.ok(
+      await PlacesUtils.bookmarks.fetch({ url }),
+      "Found the added bookmark"
+    );
+    let db = await PlacesUtils.promiseDBConnection();
+    let rows = await db.execute(
+      "SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url",
+      { url: new URL(url).href }
+    );
+    Assert.equal(rows.length, 1, "Matched the place from the database");
+    let id = rows[0].getResultByName("id");
+
+    // Now, suppose the urls has been inserted without proper parsing and retry.
+    // This should normally not happen through the API, but we have evidence
+    // it somehow happened.
+    await PlacesUtils.withConnectionWrapper("test_hash.js", async wdb => {
+      await wdb.execute(
+        `
+        UPDATE moz_places SET url_hash = hash(:url), url = :url
+        WHERE id = :id
+      `,
+        { url, id }
+      );
+      rows = await wdb.execute(
+        "SELECT id FROM moz_places WHERE url_hash = hash(:url) AND url = :url",
+        { url }
+      );
+      Assert.equal(rows.length, 1, "Matched the place from the database");
+    });
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_history.js b/toolkit/components/places/tests/unit/test_history.js
new file mode 100644
index 0000000000..3ea3696317
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_history.js
@@ -0,0 +1,158 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get history services
+var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+  Ci.nsINavHistoryService
+);
+
+/**
+ * Checks to see that a URI is in the database.
+ *
+ * @param aURI
+ *        The URI to check.
+ * @returns true if the URI is in the DB, false otherwise.
+ */
+function uri_in_db(aURI) {
+  var options = histsvc.getNewQueryOptions();
+  options.maxResults = 1;
+  options.resultType = options.RESULTS_AS_URI;
+  var query = histsvc.getNewQuery();
+  query.uri = aURI;
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var cc = root.childCount;
+  root.containerOpen = false;
+  return cc == 1;
+}
+
+// main
+
+add_task(async function test_execute() {
+  // we have a new profile, so we should have imported bookmarks
+  Assert.equal(histsvc.databaseStatus, histsvc.DATABASE_STATUS_CREATE);
+
+  // add a visit
+  var testURI = uri("http://mozilla.com");
+  await PlacesTestUtils.addVisits(testURI);
+
+  // now query for the visit, setting sorting and limit such that
+  // we should retrieve only the visit we just added
+  var options = histsvc.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.maxResults = 1;
+  options.resultType = options.RESULTS_AS_VISIT;
+  var query = histsvc.getNewQuery();
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  var cc = root.childCount;
+  for (var i = 0; i < cc; ++i) {
+    var node = root.getChild(i);
+    // test node properties in RESULTS_AS_VISIT
+    Assert.equal(node.uri, testURI.spec);
+    Assert.equal(node.type, Ci.nsINavHistoryResultNode.RESULT_TYPE_URI);
+  }
+  root.containerOpen = false;
+
+  // add another visit for the same URI, and a third visit for a different URI
+  var testURI2 = uri("http://google.com/");
+  await PlacesTestUtils.addVisits(testURI);
+  await PlacesTestUtils.addVisits(testURI2);
+
+  options.maxResults = 5;
+  options.resultType = options.RESULTS_AS_URI;
+
+  // test minVisits
+  query.minVisits = 0;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 2);
+  result.root.containerOpen = false;
+  query.minVisits = 1;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 2);
+  result.root.containerOpen = false;
+  query.minVisits = 2;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 1);
+  query.minVisits = 3;
+  result.root.containerOpen = false;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 0);
+  result.root.containerOpen = false;
+
+  // test maxVisits
+  query.minVisits = -1;
+  query.maxVisits = -1;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 2);
+  result.root.containerOpen = false;
+  query.maxVisits = 0;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 0);
+  result.root.containerOpen = false;
+  query.maxVisits = 1;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 1);
+  result.root.containerOpen = false;
+  query.maxVisits = 2;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 2);
+  result.root.containerOpen = false;
+  query.maxVisits = 3;
+  result = histsvc.executeQuery(query, options);
+  result.root.containerOpen = true;
+  Assert.equal(result.root.childCount, 2);
+  result.root.containerOpen = false;
+
+  // By default history is enabled.
+  Assert.ok(!histsvc.historyDisabled);
+
+  // test getPageTitle
+  await PlacesTestUtils.addVisits({
+    uri: uri("http://example.com"),
+    title: "title",
+  });
+  let placeInfo = await PlacesUtils.history.fetch("http://example.com");
+  Assert.equal(placeInfo.title, "title");
+
+  // query for the visit
+  Assert.ok(uri_in_db(testURI));
+
+  // test for schema changes in bug 373239
+  // get direct db connection
+  var db = histsvc.DBConnection;
+  var q = "SELECT id FROM moz_bookmarks";
+  var statement;
+  try {
+    statement = db.createStatement(q);
+  } catch (ex) {
+    do_throw("bookmarks table does not have id field, schema is too old!");
+  } finally {
+    statement.finalize();
+  }
+
+  // bug 394741 - regressed history text searches
+  await PlacesTestUtils.addVisits(uri("http://mozilla.com"));
+  options = histsvc.getNewQueryOptions();
+  // options.resultType = options.RESULTS_AS_VISIT;
+  query = histsvc.getNewQuery();
+  query.searchTerms = "moz";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.ok(root.childCount > 0);
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_history_clear.js b/toolkit/components/places/tests/unit/test_history_clear.js
new file mode 100644
index 0000000000..7c121a5b84
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_history_clear.js
@@ -0,0 +1,146 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var mDBConn = DBConn();
+
+add_task(async function test_history_clear() {
+  await PlacesTestUtils.addVisits([
+    { uri: uri("http://typed.mozilla.org/"), transition: TRANSITION_TYPED },
+    { uri: uri("http://link.mozilla.org/"), transition: TRANSITION_LINK },
+    {
+      uri: uri("http://download.mozilla.org/"),
+      transition: TRANSITION_DOWNLOAD,
+    },
+    {
+      uri: uri("http://redir_temp.mozilla.org/"),
+      transition: TRANSITION_REDIRECT_TEMPORARY,
+      referrer: "http://link.mozilla.org/",
+    },
+    {
+      uri: uri("http://redir_perm.mozilla.org/"),
+      transition: TRANSITION_REDIRECT_PERMANENT,
+      referrer: "http://link.mozilla.org/",
+    },
+  ]);
+
+  // add a place: bookmark
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: `place:parent=${PlacesUtils.bookmarks.tagsGuid}`,
+    title: "shortcut",
+  });
+
+  // Add an expire never annotation
+  // Actually expire never annotations are removed as soon as a page is removed
+  // from the database, so this should act as a normal visit.
+  await PlacesUtils.history.update({
+    url: "http://download.mozilla.org/",
+    annotations: new Map([["never", "never"]]),
+  });
+
+  // Add a bookmark
+  // Bookmarked page should have history cleared and frecency to be recalculated
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    url: "http://typed.mozilla.org/",
+    title: "bookmark",
+  });
+
+  await PlacesTestUtils.addVisits([
+    { uri: uri("http://typed.mozilla.org/"), transition: TRANSITION_BOOKMARK },
+    { uri: uri("http://frecency.mozilla.org/"), transition: TRANSITION_LINK },
+  ]);
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  // Clear history and wait for the history-cleared event notification.
+  let promiseClearHistory =
+    PlacesTestUtils.waitForNotification("history-cleared");
+  await PlacesUtils.history.clear();
+  await promiseClearHistory;
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  // Check that frecency for not cleared items (bookmarks) has been marked
+  // as to be recalculated.
+  let stmt = mDBConn.createStatement(
+    "SELECT h.id FROM moz_places h WHERE frecency <> 0 AND h.recalc_frecency = 0 "
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  stmt = mDBConn.createStatement(
+    `SELECT h.id FROM moz_places h WHERE h.recalc_frecency = 1
+       AND EXISTS (SELECT id FROM moz_bookmarks WHERE fk = h.id) LIMIT 1`
+  );
+  Assert.ok(stmt.executeStep());
+  stmt.finalize();
+
+  // Check that all visit_counts have been brought to 0
+  stmt = mDBConn.createStatement(
+    "SELECT id FROM moz_places WHERE visit_count <> 0 LIMIT 1"
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that history tables are empty
+  stmt = mDBConn.createStatement(
+    "SELECT * FROM (SELECT id FROM moz_historyvisits LIMIT 1)"
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that all moz_places entries except bookmarks and place: have been removed
+  stmt = mDBConn.createStatement(
+    `SELECT h.id FROM moz_places h WHERE
+       url_hash NOT BETWEEN hash('place', 'prefix_lo') AND hash('place', 'prefix_hi')
+       AND NOT EXISTS (SELECT id FROM moz_bookmarks WHERE fk = h.id) LIMIT 1`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that we only have favicons for retained places
+  stmt = mDBConn.createStatement(
+    `SELECT 1
+     FROM moz_pages_w_icons
+     LEFT JOIN moz_places h ON url_hash = page_url_hash AND url = page_url
+     WHERE h.id ISNULL`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+  stmt = mDBConn.createStatement(
+    `SELECT 1
+     FROM moz_icons WHERE id NOT IN (
+       SELECT icon_id FROM moz_icons_to_pages
+     )`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that we only have annotations for retained places
+  stmt = mDBConn.createStatement(
+    `SELECT a.id FROM moz_annos a WHERE NOT EXISTS
+       (SELECT id FROM moz_places WHERE id = a.place_id) LIMIT 1`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that we only have inputhistory for retained places
+  stmt = mDBConn.createStatement(
+    `SELECT i.place_id FROM moz_inputhistory i WHERE NOT EXISTS
+       (SELECT id FROM moz_places WHERE id = i.place_id) LIMIT 1`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+
+  // Check that place:uris have frecency 0
+  stmt = mDBConn.createStatement(
+    `SELECT h.id FROM moz_places h
+     WHERE url_hash BETWEEN hash('place', 'prefix_lo')
+                        AND hash('place', 'prefix_hi')
+       AND h.frecency <> 0 LIMIT 1`
+  );
+  Assert.ok(!stmt.executeStep());
+  stmt.finalize();
+});
diff --git a/toolkit/components/places/tests/unit/test_history_notifications.js b/toolkit/components/places/tests/unit/test_history_notifications.js
new file mode 100644
index 0000000000..339080b042
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_history_notifications.js
@@ -0,0 +1,50 @@
+const NS_PLACES_INIT_COMPLETE_TOPIC = "places-init-complete";
+let gLockedConn;
+
+add_task(async function setup() {
+  // Create a dummy places.sqlite and open an unshared connection on it
+  let db = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  db.append("places.sqlite");
+  gLockedConn = Services.storage.openUnsharedDatabase(db);
+  Assert.ok(db.exists(), "The database should have been created");
+
+  // We need an exclusive lock on the db
+  gLockedConn.executeSimpleSQL("PRAGMA locking_mode = EXCLUSIVE");
+  // Exclusive locking is lazy applied, we need to make a write to activate it
+  gLockedConn.executeSimpleSQL("PRAGMA USER_VERSION = 1");
+});
+
+add_task(async function locked() {
+  // Try to create history service while the db is locked.
+  // It should be possible to create the service, but any method using the
+  // database will fail.
+  let resolved = false;
+  let promiseComplete = promiseTopicObserved(
+    NS_PLACES_INIT_COMPLETE_TOPIC
+  ).then(() => (resolved = true));
+  let history = Cc["@mozilla.org/browser/nav-history-service;1"].createInstance(
+    Ci.nsINavHistoryService
+  );
+  // The notification shouldn't happen until something tries to use the database.
+  await new Promise(resolve => do_timeout(100, resolve));
+  Assert.equal(
+    resolved,
+    false,
+    "The notification should not have been fired yet"
+  );
+  // This will initialize the database.
+  Assert.equal(history.databaseStatus, history.DATABASE_STATUS_LOCKED);
+  await promiseComplete;
+
+  // Close our connection and try to cleanup the file (could fail on Windows)
+  gLockedConn.close();
+  let db = Services.dirsvc.get("ProfD", Ci.nsIFile);
+  db.append("places.sqlite");
+  if (db.exists()) {
+    try {
+      db.remove(false);
+    } catch (e) {
+      info("Unable to remove dummy places.sqlite");
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_history_observer.js b/toolkit/components/places/tests/unit/test_history_observer.js
new file mode 100644
index 0000000000..1a9323f890
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_history_observer.js
@@ -0,0 +1,186 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Registers a one-time places observer for 'page-visited',
+ * which resolves a promise on being called.
+ */
+function promiseVisitAdded(callback) {
+  return new Promise(resolve => {
+    async function listener(events) {
+      PlacesObservers.removeListener(["page-visited"], listener);
+      Assert.equal(events.length, 1, "Right number of visits notified");
+      Assert.equal(events[0].type, "page-visited");
+      await callback(events[0]);
+      resolve();
+    }
+    PlacesObservers.addListener(["page-visited"], listener);
+  });
+}
+
+/**
+ * Asynchronous task that adds a visit to the history database.
+ */
+async function task_add_visit(uri, timestamp, transition) {
+  uri = uri || NetUtil.newURI("http://firefox.com/");
+  timestamp = timestamp || Date.now() * 1000;
+  await PlacesTestUtils.addVisits({
+    uri,
+    transition: transition || TRANSITION_TYPED,
+    visitDate: timestamp,
+  });
+  return [uri, timestamp];
+}
+
+add_task(async function test_visitAdded() {
+  let promiseNotify = promiseVisitAdded(async function (visit) {
+    Assert.ok(visit.visitId > 0);
+    Assert.equal(visit.url, testuri.spec);
+    Assert.equal(visit.visitTime, testtime / 1000);
+    Assert.equal(visit.referringVisitId, 0);
+    Assert.equal(visit.transitionType, TRANSITION_TYPED);
+    let uri = NetUtil.newURI(visit.url);
+    await check_guid_for_uri(uri, visit.pageGuid);
+    Assert.ok(!visit.hidden);
+    Assert.equal(visit.visitCount, 1);
+    Assert.equal(visit.typedCount, 1);
+  });
+  let testuri = NetUtil.newURI("http://firefox.com/");
+  let testtime = Date.now() * 1000;
+  await task_add_visit(testuri, testtime);
+  await promiseNotify;
+});
+
+add_task(async function test_visitAdded() {
+  let promiseNotify = promiseVisitAdded(async function (visit) {
+    Assert.ok(visit.visitId > 0);
+    Assert.equal(visit.url, testuri.spec);
+    Assert.equal(visit.visitTime, testtime / 1000);
+    Assert.equal(visit.referringVisitId, 0);
+    Assert.equal(visit.transitionType, TRANSITION_FRAMED_LINK);
+    let uri = NetUtil.newURI(visit.url);
+    await check_guid_for_uri(uri, visit.pageGuid);
+    Assert.ok(visit.hidden);
+    Assert.equal(visit.visitCount, 1);
+    Assert.equal(visit.typedCount, 0);
+  });
+  let testuri = NetUtil.newURI("http://hidden.firefox.com/");
+  let testtime = Date.now() * 1000;
+  await task_add_visit(testuri, testtime, TRANSITION_FRAMED_LINK);
+  await promiseNotify;
+});
+
+add_task(async function test_multiple_onVisit() {
+  let testuri = NetUtil.newURI("http://self.firefox.com/");
+  let promiseNotifications = new Promise(resolve => {
+    async function listener(aEvents) {
+      Assert.equal(aEvents.length, 3, "Right number of visits notified");
+      for (let i = 0; i < aEvents.length; i++) {
+        Assert.equal(aEvents[i].type, "page-visited");
+        let visit = aEvents[i];
+        Assert.equal(testuri.spec, visit.url);
+        Assert.ok(visit.visitId > 0);
+        Assert.ok(visit.visitTime > 0);
+        Assert.ok(!visit.hidden);
+        let uri = NetUtil.newURI(visit.url);
+        await check_guid_for_uri(uri, visit.pageGuid);
+        switch (i) {
+          case 0:
+            Assert.equal(visit.referringVisitId, 0);
+            Assert.equal(visit.transitionType, TRANSITION_LINK);
+            Assert.equal(visit.visitCount, 1);
+            Assert.equal(visit.typedCount, 0);
+            break;
+          case 1:
+            Assert.ok(visit.referringVisitId > 0);
+            Assert.equal(visit.transitionType, TRANSITION_LINK);
+            Assert.equal(visit.visitCount, 2);
+            Assert.equal(visit.typedCount, 0);
+            break;
+          case 2:
+            Assert.equal(visit.referringVisitId, 0);
+            Assert.equal(visit.transitionType, TRANSITION_TYPED);
+            Assert.equal(visit.visitCount, 3);
+            Assert.equal(visit.typedCount, 1);
+
+            PlacesObservers.removeListener(["page-visited"], listener);
+            resolve();
+            break;
+        }
+      }
+    }
+    PlacesObservers.addListener(["page-visited"], listener);
+  });
+  await PlacesTestUtils.addVisits([
+    { uri: testuri, transition: TRANSITION_LINK },
+    { uri: testuri, referrer: testuri, transition: TRANSITION_LINK },
+    { uri: testuri, transition: TRANSITION_TYPED },
+  ]);
+  await promiseNotifications;
+});
+
+add_task(async function test_pageRemovedFromStore() {
+  let [testuri] = await task_add_visit();
+  let testguid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: testuri,
+  });
+
+  const promiseNotify = PlacesTestUtils.waitForNotification("page-removed");
+
+  await PlacesUtils.history.remove(testuri);
+
+  const events = await promiseNotify;
+  Assert.equal(events.length, 1, "Right number of page-removed notified");
+  Assert.equal(events[0].type, "page-removed");
+  Assert.ok(events[0].isRemovedFromStore);
+  Assert.equal(events[0].url, testuri.spec);
+  Assert.equal(events[0].pageGuid, testguid);
+  Assert.equal(events[0].reason, PlacesVisitRemoved.REASON_DELETED);
+});
+
+add_task(async function test_pageRemovedAllVisits() {
+  const promiseNotify = PlacesTestUtils.waitForNotification("page-removed");
+
+  let msecs24hrsAgo = Date.now() - 86400 * 1000;
+  let [testuri] = await task_add_visit(undefined, msecs24hrsAgo * 1000);
+  // Add a bookmark so the page is not removed.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "test",
+    url: testuri,
+  });
+  let testguid = await PlacesTestUtils.getDatabaseValue("moz_places", "guid", {
+    url: testuri,
+  });
+  await PlacesUtils.history.remove(testuri);
+
+  const events = await promiseNotify;
+  Assert.equal(events.length, 1, "Right number of page-removed notified");
+  Assert.equal(events[0].type, "page-removed");
+  Assert.ok(!events[0].isRemovedFromStore);
+  Assert.equal(events[0].url, testuri.spec);
+  // Can't use do_check_guid_for_uri() here because the visit is already gone.
+  Assert.equal(events[0].pageGuid, testguid);
+  Assert.equal(events[0].reason, PlacesVisitRemoved.REASON_DELETED);
+  Assert.ok(!events[0].isPartialVisistsRemoval); // All visits have been removed.
+});
+
+add_task(async function test_pageTitleChanged() {
+  const [testuri] = await task_add_visit();
+  const title = "test-title";
+
+  const promiseNotify =
+    PlacesTestUtils.waitForNotification("page-title-changed");
+
+  await PlacesTestUtils.addVisits({
+    uri: testuri,
+    title,
+  });
+
+  const events = await promiseNotify;
+  Assert.equal(events.length, 1, "Right number of title changed notified");
+  Assert.equal(events[0].type, "page-title-changed");
+  Assert.equal(events[0].url, testuri.spec);
+  Assert.equal(events[0].title, title);
+  await check_guid_for_uri(testuri, events[0].pageGuid);
+});
diff --git a/toolkit/components/places/tests/unit/test_history_sidebar.js b/toolkit/components/places/tests/unit/test_history_sidebar.js
new file mode 100644
index 0000000000..868ef79f70
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_history_sidebar.js
@@ -0,0 +1,418 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+let nowObj = new Date();
+
+/**
+ * Normalizes a Date to midnight.
+ *
+ * @param {Date} inputDate
+ * @return normalized Date
+ */
+function toMidnight(inputDate) {
+  let date = new Date(inputDate);
+  date.setHours(0);
+  date.setMinutes(0);
+  date.setSeconds(0);
+  date.setMilliseconds(0);
+  return date;
+}
+
+/**
+ * Adds a test URI visit to the database.
+ *
+ * @param aURI
+ *        The URI to add a visit for.
+ * @param aTime
+ *        Reference "now" time.
+ * @param aDayOffset
+ *        number of days to add, pass a negative value to subtract them.
+ */
+async function addNormalizedVisit(aURI, aTime, aDayOffset) {
+  let dateObj = toMidnight(aTime);
+  // Days where DST changes should be taken into account.
+  let previousDateObj = new Date(dateObj.getTime() + aDayOffset * 86400000);
+  let DSTCorrection =
+    (dateObj.getTimezoneOffset() - previousDateObj.getTimezoneOffset()) *
+    60 *
+    1000;
+  // Substract aDayOffset
+  let PRTimeWithOffset = (previousDateObj.getTime() - DSTCorrection) * 1000;
+  info(
+    "Adding visit to " +
+      aURI.spec +
+      " at " +
+      PlacesUtils.toDate(PRTimeWithOffset)
+  );
+  await PlacesTestUtils.addVisits({
+    uri: aURI,
+    visitDate: PRTimeWithOffset,
+  });
+}
+
+function openRootForResultType(resultType) {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = resultType;
+  let query = PlacesUtils.history.getNewQuery();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let root = result.root;
+  root.containerOpen = true;
+  return result;
+}
+
+function daysForMonthsAgo(months) {
+  let oldTime = toMidnight(new Date());
+  // Set day before month, otherwise we could try to calculate 30 February, or
+  // other nonexistent days.
+  oldTime.setDate(1);
+  oldTime.setMonth(nowObj.getMonth() - months);
+  // Stay larger for eventual timezone issues, add 2 days.
+  return parseInt((nowObj - oldTime) / (1000 * 60 * 60 * 24)) + 2;
+}
+
+// This test relies on en-US locale
+// Offset is number of days
+let containers = [
+  { label: "Today", offset: 0, visible: true },
+  { label: "Yesterday", offset: -1, visible: true },
+  { label: "Last 7 days", offset: -2, visible: true },
+  { label: "This month", offset: -8, visible: nowObj.getDate() > 8 },
+  { label: "", offset: -daysForMonthsAgo(0), visible: true },
+  { label: "", offset: -daysForMonthsAgo(1), visible: true },
+  { label: "", offset: -daysForMonthsAgo(2), visible: true },
+  { label: "", offset: -daysForMonthsAgo(3), visible: true },
+  { label: "", offset: -daysForMonthsAgo(4), visible: true },
+  { label: "Older than 6 months", offset: -daysForMonthsAgo(5), visible: true },
+];
+
+let visibleContainers = containers.filter(container => container.visible);
+
+/**
+ * Asynchronous task that fills history and checks containers' labels.
+ */
+add_task(async function task_fill_history() {
+  info("*** TEST Fill History");
+  // We can't use "now" because our hardcoded offsets would be invalid for some
+  // date.  So we hardcode a date.
+  for (let i = 0; i < containers.length; i++) {
+    let container = containers[i];
+    let testURI = uri("http://mirror" + i + ".mozilla.com/b");
+    await addNormalizedVisit(testURI, nowObj, container.offset);
+    testURI = uri("http://mirror" + i + ".mozilla.com/a");
+    await addNormalizedVisit(testURI, nowObj, container.offset);
+    testURI = uri("http://mirror" + i + ".google.com/b");
+    await addNormalizedVisit(testURI, nowObj, container.offset);
+    testURI = uri("http://mirror" + i + ".google.com/a");
+    await addNormalizedVisit(testURI, nowObj, container.offset);
+    // Bug 485703 - Hide date containers not containing additional entries
+    //              compared to previous ones.
+    // Check after every new container is added.
+    check_visit(container.offset);
+  }
+
+  let root = openRootForResultType(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  ).root;
+  let cc = root.childCount;
+  info("Found containers:");
+  let previousLabels = [];
+  for (let i = 0; i < cc; i++) {
+    let container = visibleContainers[i];
+    let node = root.getChild(i);
+    info(node.title);
+    if (container.label) {
+      Assert.equal(node.title, container.label);
+    }
+    // Check labels are not repeated.
+    Assert.ok(!previousLabels.includes(node.title));
+    previousLabels.push(node.title);
+  }
+  Assert.equal(cc, visibleContainers.length);
+  root.containerOpen = false;
+});
+
+/**
+ * Bug 485703 - Hide date containers not containing additional entries compared
+ *              to previous ones.
+ */
+function check_visit(aOffset) {
+  let root = openRootForResultType(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  ).root;
+
+  let unexpected = [];
+  switch (aOffset) {
+    case 0:
+      unexpected = ["Yesterday", "Last 7 days", "This month"];
+      break;
+    case -1:
+      unexpected = ["Last 7 days", "This month"];
+      break;
+    case -2:
+      unexpected = ["This month"];
+      break;
+    default:
+    // Other containers are tested later.
+  }
+
+  info("Found containers:");
+  let cc = root.childCount;
+  for (let i = 0; i < cc; i++) {
+    let node = root.getChild(i);
+    info(node.title);
+    Assert.ok(!unexpected.includes(node.title));
+  }
+  root.containerOpen = false;
+}
+
+/**
+ * Queries history grouped by date and site, checking containers' labels and
+ * children.
+ */
+add_task(async function test_RESULTS_AS_DATE_SITE_QUERY() {
+  info("*** TEST RESULTS_AS_DATE_SITE_QUERY");
+  let result = openRootForResultType(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  );
+  let root = result.root;
+
+  // Check one of the days
+  let dayNode = PlacesUtils.asContainer(root.getChild(0));
+  dayNode.containerOpen = true;
+  Assert.equal(dayNode.childCount, 2);
+
+  // Items should be sorted by host
+  let site1 = PlacesUtils.asContainer(dayNode.getChild(0));
+  Assert.equal(site1.title, "mirror0.google.com");
+
+  let site2 = PlacesUtils.asContainer(dayNode.getChild(1));
+  Assert.equal(site2.title, "mirror0.mozilla.com");
+
+  site1.containerOpen = true;
+  Assert.equal(site1.childCount, 2);
+
+  // Inside of host sites are sorted by title
+  let site1visit = site1.getChild(0);
+  Assert.equal(site1visit.uri, "http://mirror0.google.com/a");
+
+  // Bug 473157: changing sorting mode should not affect the containers
+  result.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING;
+
+  // Check one of the days
+  dayNode = PlacesUtils.asContainer(root.getChild(0));
+  dayNode.containerOpen = true;
+  Assert.equal(dayNode.childCount, 2);
+
+  // Hosts are still sorted by title
+  site1 = PlacesUtils.asContainer(dayNode.getChild(0));
+  Assert.equal(site1.title, "mirror0.google.com");
+
+  site2 = PlacesUtils.asContainer(dayNode.getChild(1));
+  Assert.equal(site2.title, "mirror0.mozilla.com");
+
+  site1.containerOpen = true;
+  Assert.equal(site1.childCount, 2);
+
+  // But URLs are now sorted by title descending
+  site1visit = site1.getChild(0);
+  Assert.equal(site1visit.uri, "http://mirror0.google.com/b");
+
+  site1.containerOpen = false;
+  dayNode.containerOpen = false;
+  root.containerOpen = false;
+});
+
+/**
+ * Queries history grouped by date, checking containers' labels and children.
+ */
+add_task(async function test_RESULTS_AS_DATE_QUERY() {
+  info("*** TEST RESULTS_AS_DATE_QUERY");
+  let result = openRootForResultType(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY
+  );
+  let root = result.root;
+  let cc = root.childCount;
+  Assert.equal(cc, visibleContainers.length);
+  info("Found containers:");
+  for (let i = 0; i < cc; i++) {
+    let container = visibleContainers[i];
+    let node = root.getChild(i);
+    info(node.title);
+    if (container.label) {
+      Assert.equal(node.title, container.label);
+    }
+  }
+
+  // Check one of the days
+  let dayNode = PlacesUtils.asContainer(root.getChild(0));
+  dayNode.containerOpen = true;
+  Assert.equal(dayNode.childCount, 4);
+
+  // Items should be sorted by title
+  let visit1 = dayNode.getChild(0);
+  Assert.equal(visit1.uri, "http://mirror0.google.com/a");
+
+  let visit2 = dayNode.getChild(3);
+  Assert.equal(visit2.uri, "http://mirror0.mozilla.com/b");
+
+  // Bug 473157: changing sorting mode should not affect the containers
+  result.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING;
+
+  // Check one of the days
+  dayNode = PlacesUtils.asContainer(root.getChild(0));
+  dayNode.containerOpen = true;
+  Assert.equal(dayNode.childCount, 4);
+
+  // But URLs are now sorted by title descending
+  visit1 = dayNode.getChild(0);
+  Assert.equal(visit1.uri, "http://mirror0.mozilla.com/b");
+
+  visit2 = dayNode.getChild(3);
+  Assert.equal(visit2.uri, "http://mirror0.google.com/a");
+
+  dayNode.containerOpen = false;
+  root.containerOpen = false;
+});
+
+/**
+ * Queries history grouped by site, checking containers' labels and children.
+ */
+add_task(async function test_RESULTS_AS_SITE_QUERY() {
+  info("*** TEST RESULTS_AS_SITE_QUERY");
+  // add a bookmark with a domain not in the set of visits in the db
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: "http://foobar",
+    title: "",
+  });
+
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.resultType = options.RESULTS_AS_SITE_QUERY;
+  options.sortingMode = options.SORT_BY_TITLE_ASCENDING;
+  let query = PlacesUtils.history.getNewQuery();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  let root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, containers.length * 2);
+
+  // Expected results:
+  //   "mirror0.google.com",
+  //   "mirror0.mozilla.com",
+  //   "mirror1.google.com",
+  //   "mirror1.mozilla.com",
+  //   "mirror2.google.com",
+  //   "mirror2.mozilla.com",
+  //   "mirror3.google.com",  <== We check for this site (index 6)
+  //   "mirror3.mozilla.com",
+  //   "mirror4.google.com",
+  //   "mirror4.mozilla.com",
+  //   "mirror5.google.com",
+  //   "mirror5.mozilla.com",
+  //   ...
+
+  // Items should be sorted by host
+  let siteNode = PlacesUtils.asContainer(root.getChild(6));
+  Assert.equal(siteNode.title, "mirror3.google.com");
+
+  siteNode.containerOpen = true;
+  Assert.equal(siteNode.childCount, 2);
+
+  // Inside of host sites are sorted by title
+  let visitNode = siteNode.getChild(0);
+  Assert.equal(visitNode.uri, "http://mirror3.google.com/a");
+
+  // Bug 473157: changing sorting mode should not affect the containers
+  result.sortingMode = options.SORT_BY_TITLE_DESCENDING;
+  siteNode = PlacesUtils.asContainer(root.getChild(6));
+  Assert.equal(siteNode.title, "mirror3.google.com");
+
+  siteNode.containerOpen = true;
+  Assert.equal(siteNode.childCount, 2);
+
+  // But URLs are now sorted by title descending
+  let visit = siteNode.getChild(0);
+  Assert.equal(visit.uri, "http://mirror3.google.com/b");
+
+  siteNode.containerOpen = false;
+  root.containerOpen = false;
+
+  // Cleanup.
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+});
+
+/**
+ * Checks that queries grouped by date do liveupdate correctly.
+ */
+async function test_date_liveupdate(aResultType) {
+  let midnight = toMidnight(nowObj);
+
+  // TEST 1. Test that the query correctly updates when it is root.
+  let root = openRootForResultType(aResultType).root;
+  Assert.equal(root.childCount, visibleContainers.length);
+
+  // Remove "Today".
+  await PlacesUtils.history.removeByFilter({
+    beginDate: new Date(midnight.getTime()),
+    endDate: new Date(Date.now()),
+  });
+  Assert.equal(root.childCount, visibleContainers.length - 1);
+
+  // Open "Last 7 days" container, this way we will have a container accepting
+  // the new visit, but we should still add back "Today" container.
+  let last7Days = PlacesUtils.asContainer(root.getChild(1));
+  last7Days.containerOpen = true;
+
+  // Add a visit for "Today".  This should add back the missing "Today"
+  // container.
+  await addNormalizedVisit(uri("http://www.mozilla.org/"), nowObj, 0);
+  Assert.equal(root.childCount, visibleContainers.length);
+
+  last7Days.containerOpen = false;
+  root.containerOpen = false;
+
+  // TEST 2. Test that the query correctly updates even if it is not root.
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    url: "place:type=" + aResultType,
+    title: "",
+  });
+
+  // Query toolbar and open our query container, then check again liveupdate.
+  root = PlacesUtils.getFolderContents(PlacesUtils.bookmarks.toolbarGuid).root;
+  Assert.equal(root.childCount, 1);
+  let dateContainer = PlacesUtils.asContainer(root.getChild(0));
+  dateContainer.containerOpen = true;
+
+  Assert.equal(dateContainer.childCount, visibleContainers.length);
+  // Remove "Today".
+  await PlacesUtils.history.removeByFilter({
+    beginDate: new Date(midnight.getTime()),
+    endDate: new Date(Date.now()),
+  });
+  Assert.equal(dateContainer.childCount, visibleContainers.length - 1);
+  // Add a visit for "Today".
+  await addNormalizedVisit(uri("http://www.mozilla.org/"), nowObj, 0);
+  Assert.equal(dateContainer.childCount, visibleContainers.length);
+
+  dateContainer.containerOpen = false;
+  root.containerOpen = false;
+
+  // Cleanup.
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+}
+
+add_task(async function test_history_sidebar() {
+  await test_date_liveupdate(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY
+  );
+  await test_date_liveupdate(
+    Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY
+  );
+
+  // The remaining views are
+  //   RESULTS_AS_URI + SORT_BY_VISITCOUNT_DESCENDING
+  //   ->  test_399266.js
+  //   RESULTS_AS_URI + SORT_BY_DATE_DESCENDING
+  //   ->  test_385397.js
+});
diff --git a/toolkit/components/places/tests/unit/test_import_mobile_bookmarks.js b/toolkit/components/places/tests/unit/test_import_mobile_bookmarks.js
new file mode 100644
index 0000000000..167b8786e4
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_import_mobile_bookmarks.js
@@ -0,0 +1,326 @@
+async function importFromFixture(fixture, replace) {
+  let cwd = do_get_cwd().path;
+  let path = PathUtils.join(cwd, fixture);
+
+  info(`Importing from ${path}`);
+  await BookmarkJSONUtils.importFromFile(path, { replace });
+  await PlacesTestUtils.promiseAsyncUpdates();
+}
+
+async function treeEquals(guid, expected, message) {
+  let root = await PlacesUtils.promiseBookmarksTree(guid);
+  let bookmarks = (function nodeToEntry(node) {
+    let entry = { guid: node.guid, index: node.index };
+    if (node.children) {
+      entry.children = node.children.map(nodeToEntry);
+    }
+    return entry;
+  })(root);
+
+  info(`Checking if ${guid} tree matches ${JSON.stringify(expected)}`);
+  info(`Got bookmarks tree for ${guid}: ${JSON.stringify(bookmarks)}`);
+
+  deepEqual(bookmarks, expected, message);
+}
+
+add_task(async function test_restore_mobile_bookmarks_root() {
+  await importFromFixture(
+    "mobile_bookmarks_root_import.json",
+    /* replace */ true
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [{ guid: "X6lUyOspVYwi", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            { guid: "_o8e1_zxTJFg", index: 0 },
+            { guid: "QCtSqkVYUbXB", index: 1 },
+          ],
+        },
+      ],
+    },
+    "Should restore mobile bookmarks from root"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_mobile_bookmarks_root() {
+  await importFromFixture(
+    "mobile_bookmarks_root_import.json",
+    /* replace */ false
+  );
+  await importFromFixture(
+    "mobile_bookmarks_root_merge.json",
+    /* replace */ false
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [
+            { guid: "X6lUyOspVYwi", index: 0 },
+            { guid: "Utodo9b0oVws", index: 1 },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            // The first two are in ..._import.json, the second two are in
+            // ..._merge.json
+            { guid: "_o8e1_zxTJFg", index: 0 },
+            { guid: "QCtSqkVYUbXB", index: 1 },
+            { guid: "a17yW6-nTxEJ", index: 2 },
+            { guid: "xV10h9Wi3FBM", index: 3 },
+          ],
+        },
+      ],
+    },
+    "Should merge bookmarks root contents"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_restore_mobile_bookmarks_folder() {
+  // This tests importing a mobile bookmarks folder with the annotation,
+  // and the old, random guid.
+  await importFromFixture(
+    "mobile_bookmarks_folder_import.json",
+    /* replace */ true
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [
+            { guid: "X6lUyOspVYwi", index: 0 },
+            { guid: "XF4yRP6bTuil", index: 1 },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+          children: [{ guid: "buy7711R3ZgE", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+          children: [{ guid: "KIa9iKZab2Z5", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            { guid: "_o8e1_zxTJFg", index: 0 },
+            { guid: "QCtSqkVYUbXB", index: 1 },
+          ],
+        },
+      ],
+    },
+    "Should restore mobile bookmark folder contents into mobile root"
+  );
+
+  let queryById = await PlacesUtils.bookmarks.fetch("XF4yRP6bTuil");
+  equal(
+    queryById.url.href,
+    `place:parent=${PlacesUtils.bookmarks.mobileGuid}`,
+    "Should rewrite mobile query to point to root GUID"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_mobile_bookmarks_folder() {
+  await importFromFixture(
+    "mobile_bookmarks_folder_import.json",
+    /* replace */ false
+  );
+  await importFromFixture(
+    "mobile_bookmarks_folder_merge.json",
+    /* replace */ false
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [
+            { guid: "X6lUyOspVYwi", index: 0 },
+            { guid: "XF4yRP6bTuil", index: 1 },
+            { guid: "Utodo9b0oVws", index: 2 },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+          children: [{ guid: "buy7711R3ZgE", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+          children: [{ guid: "KIa9iKZab2Z5", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            { guid: "_o8e1_zxTJFg", index: 0 },
+            { guid: "QCtSqkVYUbXB", index: 1 },
+            { guid: "a17yW6-nTxEJ", index: 2 },
+            { guid: "xV10h9Wi3FBM", index: 3 },
+          ],
+        },
+      ],
+    },
+    "Should merge bookmarks folder contents into mobile root"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_restore_multiple_bookmarks_folders() {
+  await importFromFixture(
+    "mobile_bookmarks_multiple_folders.json",
+    /* replace */ true
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [
+            { guid: "buy7711R3ZgE", index: 0 },
+            { guid: "F_LBgd1fS_uQ", index: 1 },
+            { guid: "oIpmQXMWsXvY", index: 2 },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+          children: [{ guid: "Utodo9b0oVws", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+          children: [{ guid: "xV10h9Wi3FBM", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            { guid: "a17yW6-nTxEJ", index: 0 },
+            { guid: "sSZ86WT9WbN3", index: 1 },
+          ],
+        },
+      ],
+    },
+    "Should restore multiple bookmarks folder contents into root"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_import_multiple_bookmarks_folders() {
+  await importFromFixture(
+    "mobile_bookmarks_root_import.json",
+    /* replace */ false
+  );
+  await importFromFixture(
+    "mobile_bookmarks_multiple_folders.json",
+    /* replace */ false
+  );
+
+  await treeEquals(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+      index: 0,
+      children: [
+        {
+          guid: PlacesUtils.bookmarks.menuGuid,
+          index: 0,
+          children: [
+            { guid: "X6lUyOspVYwi", index: 0 },
+            { guid: "buy7711R3ZgE", index: 1 },
+            { guid: "F_LBgd1fS_uQ", index: 2 },
+            { guid: "oIpmQXMWsXvY", index: 3 },
+          ],
+        },
+        {
+          guid: PlacesUtils.bookmarks.toolbarGuid,
+          index: 1,
+          children: [{ guid: "Utodo9b0oVws", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.unfiledGuid,
+          index: 3,
+          children: [{ guid: "xV10h9Wi3FBM", index: 0 }],
+        },
+        {
+          guid: PlacesUtils.bookmarks.mobileGuid,
+          index: 4,
+          children: [
+            { guid: "_o8e1_zxTJFg", index: 0 },
+            { guid: "QCtSqkVYUbXB", index: 1 },
+            { guid: "a17yW6-nTxEJ", index: 2 },
+            { guid: "sSZ86WT9WbN3", index: 3 },
+          ],
+        },
+      ],
+    },
+    "Should merge multiple mobile folders into root"
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/unit/test_isPageInDB.js b/toolkit/components/places/tests/unit/test_isPageInDB.js
new file mode 100644
index 0000000000..2eda125994
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_isPageInDB.js
@@ -0,0 +1,10 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+add_task(async function test_execute() {
+  var good_uri = uri("http://mozilla.com");
+  var bad_uri = uri("http://google.com");
+  await PlacesTestUtils.addVisits({ uri: good_uri });
+  Assert.ok(await PlacesTestUtils.isPageInDB(good_uri));
+  Assert.equal(false, await PlacesTestUtils.isPageInDB(bad_uri));
+});
diff --git a/toolkit/components/places/tests/unit/test_isURIVisited.js b/toolkit/components/places/tests/unit/test_isURIVisited.js
new file mode 100644
index 0000000000..ac40e5fba6
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_isURIVisited.js
@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests functionality of the isURIVisited API.
+
+const SCHEMES = {
+  "http://": true,
+  "https://": true,
+  "ftp://": true,
+  "file:///": true,
+  "about:": false,
+  // nsIIOService.newURI() can throw if e.g. the app knows about imap://
+  // but the account is not set up and so the URL is invalid for it.
+  //  "imap://": false,
+  "news://": false,
+  "mailbox:": false,
+  "cached-favicon:http://": false,
+  "view-source:http://": false,
+  "chrome://browser/content/browser.xhtml?": false,
+  "resource://": false,
+  "data:,": false,
+  "javascript:": false,
+};
+
+add_task(async function test_isURIVisited() {
+  let history = Cc["@mozilla.org/browser/history;1"].getService(
+    Ci.mozIAsyncHistory
+  );
+
+  function visitsPromise(uri) {
+    return new Promise(resolve => {
+      history.isURIVisited(uri, (receivedURI, visited) => {
+        resolve([receivedURI, visited]);
+      });
+    });
+  }
+
+  for (let scheme in SCHEMES) {
+    info("Testing scheme " + scheme);
+    for (let t in PlacesUtils.history.TRANSITIONS) {
+      if (t == "EMBED") {
+        continue;
+      }
+      info("With transition " + t);
+      let aTransition = PlacesUtils.history.TRANSITIONS[t];
+
+      let aURI = Services.io.newURI(scheme + "mozilla.org/");
+
+      let [receivedURI1, visited1] = await visitsPromise(aURI);
+      Assert.ok(aURI.equals(receivedURI1));
+      Assert.ok(!visited1);
+
+      if (PlacesUtils.history.canAddURI(aURI)) {
+        await PlacesTestUtils.addVisits([
+          {
+            uri: aURI,
+            transition: aTransition,
+          },
+        ]);
+        info("Added visit for " + aURI.spec);
+      }
+
+      let [receivedURI2, visited2] = await visitsPromise(aURI);
+      Assert.ok(aURI.equals(receivedURI2));
+      Assert.equal(SCHEMES[scheme], visited2);
+
+      await PlacesUtils.history.clear();
+      let [receivedURI3, visited3] = await visitsPromise(aURI);
+      Assert.ok(aURI.equals(receivedURI3));
+      Assert.ok(!visited3);
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_isvisited.js b/toolkit/components/places/tests/unit/test_isvisited.js
new file mode 100644
index 0000000000..7271ef7903
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_isvisited.js
@@ -0,0 +1,69 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test_execute() {
+  var referrer = uri("about:blank");
+
+  // add a http:// uri
+  var uri1 = uri("http://mozilla.com");
+  await PlacesTestUtils.addVisits({ uri: uri1, referrer });
+  await check_guid_for_uri(uri1);
+  Assert.ok(await PlacesUtils.history.hasVisits(uri1));
+
+  // add a https:// uri
+  var uri2 = uri("https://etrade.com");
+  await PlacesTestUtils.addVisits({ uri: uri2, referrer });
+  await check_guid_for_uri(uri2);
+  Assert.ok(await PlacesUtils.history.hasVisits(uri2));
+
+  // add a ftp:// uri
+  var uri3 = uri("ftp://ftp.mozilla.org");
+  await PlacesTestUtils.addVisits({ uri: uri3, referrer });
+  await check_guid_for_uri(uri3);
+  Assert.ok(await PlacesUtils.history.hasVisits(uri3));
+
+  // check if a nonexistent uri is visited
+  var uri4 = uri("http://foobarcheese.com");
+  Assert.equal(false, await PlacesUtils.history.hasVisits(uri4));
+
+  // check that certain schemes never show up as visited
+  // even if we attempt to add them to history
+  // see CanAddURI() in nsNavHistory.cpp
+  const URLS = [
+    "about:config",
+    "imap://cyrus.andrew.cmu.edu/archive.imap",
+    "news://new.mozilla.org/mozilla.dev.apps.firefox",
+    "mailbox:Inbox",
+    "cached-favicon:http://mozilla.org/made-up-favicon",
+    "view-source:http://mozilla.org",
+    "chrome://browser/content/browser.xhtml",
+    "resource://gre-resources/hiddenWindow.html",
+    "data:,Hello%2C%20World!",
+    "javascript:alert('hello wolrd!');",
+    "http://localhost/" + "a".repeat(1984),
+  ];
+  for (let currentURL of URLS) {
+    try {
+      var cantAddUri = uri(currentURL);
+    } catch (e) {
+      // nsIIOService.newURI() can throw if e.g. our app knows about imap://
+      // but the account is not set up and so the URL is invalid for us.
+      // Note this in the log but ignore as it's not the subject of this test.
+      info("Could not construct URI for '" + currentURL + "'; ignoring");
+    }
+    if (cantAddUri) {
+      PlacesTestUtils.addVisits({ uri: cantAddUri, referrer }).then(
+        () => {
+          do_throw("Should not have added history for invalid URI.");
+        },
+        error => {
+          Assert.ok(error.message.includes("No items were added to history"));
+        }
+      );
+      Assert.equal(false, await PlacesUtils.history.hasVisits(cantAddUri));
+    }
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_keywords.js b/toolkit/components/places/tests/unit/test_keywords.js
new file mode 100644
index 0000000000..8ee3ecafe2
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_keywords.js
@@ -0,0 +1,733 @@
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+async function check_keyword(aExpectExists, aHref, aKeyword, aPostData = null) {
+  // Check case-insensitivity.
+  aKeyword = aKeyword.toUpperCase();
+
+  let entry = await PlacesUtils.keywords.fetch(aKeyword);
+
+  Assert.deepEqual(
+    entry,
+    await PlacesUtils.keywords.fetch({ keyword: aKeyword })
+  );
+
+  if (aExpectExists) {
+    Assert.ok(!!entry, "A keyword should exist");
+    Assert.equal(entry.url.href, aHref);
+    Assert.equal(entry.postData, aPostData);
+    Assert.deepEqual(
+      entry,
+      await PlacesUtils.keywords.fetch({ keyword: aKeyword, url: aHref })
+    );
+    let entries = [];
+    await PlacesUtils.keywords.fetch({ url: aHref }, e => entries.push(e));
+    Assert.ok(
+      entries.some(
+        e => e.url.href == aHref && e.keyword == aKeyword.toLowerCase()
+      )
+    );
+  } else {
+    Assert.ok(
+      !entry || entry.url.href != aHref,
+      "The given keyword entry should not exist"
+    );
+    if (aHref) {
+      Assert.equal(
+        null,
+        await PlacesUtils.keywords.fetch({ keyword: aKeyword, url: aHref })
+      );
+    } else {
+      Assert.equal(
+        null,
+        await PlacesUtils.keywords.fetch({ keyword: aKeyword })
+      );
+    }
+  }
+}
+
+/**
+ * Polls the keywords cache waiting for the given keyword entry.
+ */
+async function promiseKeyword(keyword, expectedHref) {
+  let href = null;
+  do {
+    await new Promise(resolve => do_timeout(100, resolve));
+    let entry = await PlacesUtils.keywords.fetch(keyword);
+    if (entry) {
+      href = entry.url.href;
+    }
+  } while (href != expectedHref);
+}
+
+async function check_no_orphans() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.executeCached(
+    `SELECT id FROM moz_keywords k
+     WHERE NOT EXISTS (SELECT 1 FROM moz_places WHERE id = k.place_id)
+    `
+  );
+  Assert.equal(rows.length, 0);
+}
+
+function expectBookmarkNotifications() {
+  const observer = {
+    notifications: [],
+    _start() {
+      this._handle = this._handle.bind(this);
+      PlacesUtils.observers.addListener(
+        ["bookmark-keyword-changed"],
+        this._handle
+      );
+    },
+    _handle(events) {
+      for (const event of events) {
+        this.notifications.push({
+          type: event.type,
+          id: event.id,
+          itemType: event.itemType,
+          url: event.url,
+          guid: event.guid,
+          parentGuid: event.parentGuid,
+          keyword: event.keyword,
+          lastModified: new Date(event.lastModified),
+          source: event.source,
+          isTagging: event.isTagging,
+        });
+      }
+    },
+    check(expected) {
+      PlacesUtils.observers.removeListener(
+        ["bookmark-keyword-changed"],
+        this._handle
+      );
+      Assert.deepEqual(this.notifications, expected);
+    },
+  };
+  observer._start();
+  return observer;
+}
+
+add_task(async function test_invalid_input() {
+  Assert.throws(() => PlacesUtils.keywords.fetch(null), /Invalid keyword/);
+  Assert.throws(() => PlacesUtils.keywords.fetch(5), /Invalid keyword/);
+  Assert.throws(() => PlacesUtils.keywords.fetch(undefined), /Invalid keyword/);
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ keyword: null }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ keyword: {} }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ keyword: 5 }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({}),
+    /At least keyword or url must be provided/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ keyword: "test" }, "test"),
+    /onResult callback must be a valid function/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ url: "test" }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ url: {} }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ url: null }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.fetch({ url: "" }),
+    /is not a valid URL/
+  );
+
+  Assert.throws(
+    () => PlacesUtils.keywords.insert(null),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert("test"),
+    /Input should be a valid object/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert(undefined),
+    /Input should be a valid object/
+  );
+  Assert.throws(() => PlacesUtils.keywords.insert({}), /Invalid keyword/);
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: null }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: 5 }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "" }),
+    /Invalid keyword/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", postData: 5 }),
+    /Invalid POST data/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", postData: {} }),
+    /Invalid POST data/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test" }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", url: 5 }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", url: "" }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", url: null }),
+    /is not a valid URL/
+  );
+  Assert.throws(
+    () => PlacesUtils.keywords.insert({ keyword: "test", url: "mozilla" }),
+    /is not a valid URL/
+  );
+
+  Assert.throws(() => PlacesUtils.keywords.remove(null), /Invalid keyword/);
+  Assert.throws(() => PlacesUtils.keywords.remove(""), /Invalid keyword/);
+  Assert.throws(() => PlacesUtils.keywords.remove(5), /Invalid keyword/);
+});
+
+add_task(async function test_addKeyword() {
+  await check_keyword(false, "http://example.com/", "keyword");
+  let fc = await foreign_count("http://example.com/");
+  let observer = expectBookmarkNotifications();
+
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+  observer.check([]);
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 1); // +1 keyword
+
+  // Now remove the keyword.
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.remove("keyword");
+  observer.check([]);
+
+  await check_keyword(false, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc); // -1 keyword
+
+  // Check using URL.
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: new URL("http://example.com/"),
+  });
+  await check_keyword(true, "http://example.com/", "keyword");
+  await PlacesUtils.keywords.remove("keyword");
+  await check_keyword(false, "http://example.com/", "keyword");
+
+  await check_no_orphans();
+});
+
+add_task(async function test_addBookmarkAndKeyword() {
+  let timerPrecision = Preferences.get("privacy.reduceTimerPrecision");
+  Preferences.set("privacy.reduceTimerPrecision", false);
+
+  registerCleanupFunction(function () {
+    Preferences.set("privacy.reduceTimerPrecision", timerPrecision);
+  });
+
+  await check_keyword(false, "http://example.com/", "keyword");
+  let fc = await foreign_count("http://example.com/");
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+
+  let observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark.guid),
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // +1 bookmark +1 keyword
+
+  // Now remove the keyword.
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.remove("keyword");
+
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark.guid),
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(false, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 1); // -1 keyword
+
+  // Add again the keyword, then remove the bookmark.
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+  // the notification is synchronous but the removal process is async.
+  // Unfortunately there's nothing explicit we can wait for.
+  // eslint-disable-next-line no-empty
+  while (await foreign_count("http://example.com/")) {}
+  // We don't get any itemChanged notification since the bookmark has been
+  // removed already.
+  observer.check([]);
+
+  await check_keyword(false, "http://example.com/", "keyword");
+
+  await check_no_orphans();
+});
+
+add_task(async function test_addKeywordToURIHavingKeyword() {
+  await check_keyword(false, "http://example.com/", "keyword");
+  let fc = await foreign_count("http://example.com/");
+
+  let observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+  observer.check([]);
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 1); // +1 keyword
+
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword2",
+    url: "http://example.com/",
+    postData: "test=1",
+  });
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  await check_keyword(true, "http://example.com/", "keyword2", "test=1");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // +1 keyword
+  let entries = [];
+  let entry = await PlacesUtils.keywords.fetch(
+    { url: "http://example.com/" },
+    e => entries.push(e)
+  );
+  Assert.equal(entries.length, 2);
+  Assert.deepEqual(entries[0], entry);
+
+  // Now remove the keywords.
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.remove("keyword");
+  await PlacesUtils.keywords.remove("keyword2");
+  observer.check([]);
+
+  await check_keyword(false, "http://example.com/", "keyword");
+  await check_keyword(false, "http://example.com/", "keyword2");
+  Assert.equal(await foreign_count("http://example.com/"), fc); // -1 keyword
+
+  await check_no_orphans();
+});
+
+add_task(async function test_addBookmarkToURIHavingKeyword() {
+  await check_keyword(false, "http://example.com/", "keyword");
+  let fc = await foreign_count("http://example.com/");
+  let observer = expectBookmarkNotifications();
+
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+  observer.check([]);
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 1); // +1 keyword
+
+  observer = expectBookmarkNotifications();
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // +1 bookmark
+  observer.check([]);
+
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+  // the notification is synchronous but the removal process is async.
+  // Unfortunately there's nothing explicit we can wait for.
+  // eslint-disable-next-line no-empty
+  while (await foreign_count("http://example.com/")) {}
+  // We don't get any itemChanged notification since the bookmark has been
+  // removed already.
+  observer.check([]);
+
+  await check_keyword(false, "http://example.com/", "keyword");
+
+  await check_no_orphans();
+});
+
+add_task(async function test_sameKeywordDifferentURL() {
+  let fc1 = await foreign_count("http://example1.com/");
+  let bookmark1 = await PlacesUtils.bookmarks.insert({
+    url: "http://example1.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let fc2 = await foreign_count("http://example2.com/");
+  let bookmark2 = await PlacesUtils.bookmarks.insert({
+    url: "http://example2.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example1.com/",
+  });
+
+  await check_keyword(true, "http://example1.com/", "keyword");
+  Assert.equal(await foreign_count("http://example1.com/"), fc1 + 2); // +1 bookmark +1 keyword
+  await check_keyword(false, "http://example2.com/", "keyword");
+  Assert.equal(await foreign_count("http://example2.com/"), fc2 + 1); // +1 bookmark
+
+  // Assign the same keyword to another url.
+  let observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example2.com/",
+  });
+
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark1.guid),
+      itemType: bookmark1.type,
+      url: bookmark1.url,
+      guid: bookmark1.guid,
+      parentGuid: bookmark1.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark1.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark2.guid),
+      itemType: bookmark2.type,
+      url: bookmark2.url,
+      guid: bookmark2.guid,
+      parentGuid: bookmark2.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark2.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(false, "http://example1.com/", "keyword");
+  Assert.equal(await foreign_count("http://example1.com/"), fc1 + 1); // -1 keyword
+  await check_keyword(true, "http://example2.com/", "keyword");
+  Assert.equal(await foreign_count("http://example2.com/"), fc2 + 2); // +1 keyword
+
+  // Now remove the keyword.
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.remove("keyword");
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark2.guid),
+      itemType: bookmark2.type,
+      url: bookmark2.url,
+      guid: bookmark2.guid,
+      parentGuid: bookmark2.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark2.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  await check_keyword(false, "http://example1.com/", "keyword");
+  await check_keyword(false, "http://example2.com/", "keyword");
+  Assert.equal(await foreign_count("http://example1.com/"), fc1 + 1);
+  Assert.equal(await foreign_count("http://example2.com/"), fc2 + 1); // -1 keyword
+
+  await PlacesUtils.bookmarks.remove(bookmark1);
+  await PlacesUtils.bookmarks.remove(bookmark2);
+  Assert.equal(await foreign_count("http://example1.com/"), fc1); // -1 bookmark
+  // eslint-disable-next-line no-empty
+  while (await foreign_count("http://example2.com/")) {} // -1 keyword
+
+  await check_no_orphans();
+});
+
+add_task(async function test_sameURIDifferentKeyword() {
+  let fc = await foreign_count("http://example.com/");
+
+  let observer = expectBookmarkNotifications();
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // +1 bookmark +1 keyword
+
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark.guid),
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword2",
+    url: "http://example.com/",
+  });
+  await check_keyword(false, "http://example.com/", "keyword");
+  await check_keyword(true, "http://example.com/", "keyword2");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // -1 keyword +1 keyword
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark.guid),
+      itemType: bookmark.type,
+      url: bookmark.url,
+      guid: bookmark.guid,
+      parentGuid: bookmark.parentGuid,
+      keyword: "keyword2",
+      lastModified: new Date(bookmark.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  // Now remove the bookmark.
+  await PlacesUtils.bookmarks.remove(bookmark);
+  // eslint-disable-next-line no-empty
+  while (await foreign_count("http://example.com/")) {}
+  await check_keyword(false, "http://example.com/", "keyword");
+  await check_keyword(false, "http://example.com/", "keyword2");
+
+  await check_no_orphans();
+});
+
+add_task(async function test_deleteKeywordMultipleBookmarks() {
+  let fc = await foreign_count("http://example.com/");
+
+  let observer = expectBookmarkNotifications();
+  let bookmark1 = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  let bookmark2 = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+  });
+
+  await check_keyword(true, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 3); // +2 bookmark +1 keyword
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark2.guid),
+      itemType: bookmark2.type,
+      url: bookmark2.url,
+      guid: bookmark2.guid,
+      parentGuid: bookmark2.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark2.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark1.guid),
+      itemType: bookmark1.type,
+      url: bookmark1.url,
+      guid: bookmark1.guid,
+      parentGuid: bookmark1.parentGuid,
+      keyword: "keyword",
+      lastModified: new Date(bookmark1.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  observer = expectBookmarkNotifications();
+  await PlacesUtils.keywords.remove("keyword");
+  await check_keyword(false, "http://example.com/", "keyword");
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // -1 keyword
+  observer.check([
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark2.guid),
+      itemType: bookmark2.type,
+      url: bookmark2.url,
+      guid: bookmark2.guid,
+      parentGuid: bookmark2.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark2.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+    {
+      type: "bookmark-keyword-changed",
+      id: await PlacesTestUtils.promiseItemId(bookmark1.guid),
+      itemType: bookmark1.type,
+      url: bookmark1.url,
+      guid: bookmark1.guid,
+      parentGuid: bookmark1.parentGuid,
+      keyword: "",
+      lastModified: new Date(bookmark1.lastModified),
+      source: Ci.nsINavBookmarksService.SOURCE_DEFAULT,
+      isTagging: false,
+    },
+  ]);
+
+  // Now remove the bookmarks.
+  await PlacesUtils.bookmarks.remove(bookmark1);
+  await PlacesUtils.bookmarks.remove(bookmark2);
+  Assert.equal(await foreign_count("http://example.com/"), fc); // -2 bookmarks
+
+  await check_no_orphans();
+});
+
+add_task(async function test_multipleKeywordsSamePostData() {
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example.com/",
+    postData: "postData1",
+  });
+  await check_keyword(true, "http://example.com/", "keyword", "postData1");
+  // Add another keyword with same postData, should fail.
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword2",
+    url: "http://example.com/",
+    postData: "postData1",
+  });
+  await check_keyword(false, "http://example.com/", "keyword", "postData1");
+  await check_keyword(true, "http://example.com/", "keyword2", "postData1");
+
+  await PlacesUtils.keywords.remove("keyword2");
+
+  await check_no_orphans();
+});
+
+add_task(async function test_bookmarkURLChange() {
+  let fc1 = await foreign_count("http://example1.com/");
+  let fc2 = await foreign_count("http://example2.com/");
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    url: "http://example1.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  await PlacesUtils.keywords.insert({
+    keyword: "keyword",
+    url: "http://example1.com/",
+  });
+
+  await check_keyword(true, "http://example1.com/", "keyword");
+  Assert.equal(await foreign_count("http://example1.com/"), fc1 + 2); // +1 bookmark +1 keyword
+
+  await PlacesUtils.bookmarks.update({
+    guid: bookmark.guid,
+    url: "http://example2.com/",
+  });
+  await promiseKeyword("keyword", "http://example2.com/");
+
+  await check_keyword(false, "http://example1.com/", "keyword");
+  await check_keyword(true, "http://example2.com/", "keyword");
+  Assert.equal(await foreign_count("http://example1.com/"), fc1); // -1 bookmark -1 keyword
+  Assert.equal(await foreign_count("http://example2.com/"), fc2 + 2); // +1 bookmark +1 keyword
+});
+
+add_task(async function test_tagDoesntPreventKeywordRemoval() {
+  await check_keyword(false, "http://example.com/", "example");
+  let fc = await foreign_count("http://example.com/");
+
+  let httpBookmark = await PlacesUtils.bookmarks.insert({
+    url: "http://example.com/",
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+  });
+  Assert.equal(await foreign_count("http://example.com/"), fc + 1); // +1 bookmark
+
+  PlacesUtils.tagging.tagURI(uri("http://example.com/"), ["example_tag"]);
+  Assert.equal(await foreign_count("http://example.com/"), fc + 2); // +1 bookmark +1 tag
+
+  await PlacesUtils.keywords.insert({
+    keyword: "example",
+    url: "http://example.com/",
+  });
+  Assert.equal(await foreign_count("http://example.com/"), fc + 3); // +1 bookmark +1 tag +1 keyword
+
+  await check_keyword(true, "http://example.com/", "example");
+
+  await PlacesUtils.bookmarks.remove(httpBookmark);
+
+  await TestUtils.waitForCondition(
+    async () =>
+      !(await PlacesUtils.bookmarks.fetch({ url: "http://example.com/" })),
+    "Wait for bookmark to be removed"
+  );
+
+  await check_keyword(false, "http://example.com/", "example");
+  Assert.equal(await foreign_count("http://example.com/"), fc); // bookmark, keyword, and tag should all have been removed
+
+  await check_no_orphans();
+});
diff --git a/toolkit/components/places/tests/unit/test_lastModified.js b/toolkit/components/places/tests/unit/test_lastModified.js
new file mode 100644
index 0000000000..dc44814548
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_lastModified.js
@@ -0,0 +1,78 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function assert_date_eq(a, b) {
+  if (typeof a != "number") {
+    a = PlacesUtils.toPRTime(a);
+  }
+  if (typeof b != "number") {
+    b = PlacesUtils.toPRTime(b);
+  }
+  Assert.equal(a, b, "The dates should match");
+}
+
+/**
+ * Test that inserting a new bookmark will set lastModified to the same
+ * values as dateAdded.
+ */
+add_task(async function test_bookmarkLastModified() {
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://www.mozilla.org/",
+    title: "itemTitle",
+  });
+
+  let guid = bookmark.guid;
+
+  // Check the bookmark from the database.
+  bookmark = await PlacesUtils.bookmarks.fetch(guid);
+
+  let dateAdded = PlacesUtils.toPRTime(bookmark.dateAdded);
+  assert_date_eq(dateAdded, bookmark.lastModified);
+
+  // Change lastModified, then change dateAdded.  LastModified should be set
+  // to the new dateAdded.
+  // This could randomly fail on virtual machines due to timing issues, so
+  // we manually increase the time value.  See bug 500640 for details.
+  await PlacesUtils.bookmarks.update({
+    guid,
+    lastModified: PlacesUtils.toDate(dateAdded + 1000),
+  });
+
+  bookmark = await PlacesUtils.bookmarks.fetch(guid);
+
+  assert_date_eq(bookmark.lastModified, dateAdded + 1000);
+  Assert.ok(
+    bookmark.dateAdded < bookmark.lastModified,
+    "Date added should be earlier than last modified."
+  );
+
+  await PlacesUtils.bookmarks.update({
+    guid,
+    dateAdded: PlacesUtils.toDate(dateAdded + 2000),
+  });
+
+  bookmark = await PlacesUtils.bookmarks.fetch(guid);
+
+  assert_date_eq(bookmark.dateAdded, dateAdded + 2000);
+  assert_date_eq(bookmark.dateAdded, bookmark.lastModified);
+
+  // If dateAdded is set to older than lastModified, then we shouldn't
+  // update lastModified to keep sync happy.
+  let origLastModified = bookmark.lastModified;
+
+  await PlacesUtils.bookmarks.update({
+    guid,
+    dateAdded: PlacesUtils.toDate(dateAdded - 10000),
+  });
+
+  bookmark = await PlacesUtils.bookmarks.fetch(guid);
+
+  assert_date_eq(bookmark.dateAdded, dateAdded - 10000);
+  assert_date_eq(bookmark.lastModified, origLastModified);
+
+  await PlacesUtils.bookmarks.remove(guid);
+});
diff --git a/toolkit/components/places/tests/unit/test_markpageas.js b/toolkit/components/places/tests/unit/test_markpageas.js
new file mode 100644
index 0000000000..03080f4af6
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_markpageas.js
@@ -0,0 +1,48 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var gVisits = [
+  { url: "http://www.mozilla.com/", transition: TRANSITION_TYPED },
+  { url: "http://www.google.com/", transition: TRANSITION_BOOKMARK },
+  { url: "http://www.espn.com/", transition: TRANSITION_LINK },
+];
+
+add_task(async function test_execute() {
+  let completionPromise = new Promise(resolveCompletionPromise => {
+    let visitCount = 0;
+    function listener(aEvents) {
+      Assert.equal(aEvents.length, 1, "Right number of visits notified");
+      Assert.equal(aEvents[0].type, "page-visited");
+      let event = aEvents[0];
+      Assert.equal(event.url, gVisits[visitCount].url);
+      Assert.equal(event.transitionType, gVisits[visitCount].transition);
+      visitCount++;
+
+      if (visitCount == gVisits.length) {
+        resolveCompletionPromise();
+        PlacesObservers.removeListener(["page-visited"], listener);
+      }
+    }
+    PlacesObservers.addListener(["page-visited"], listener);
+  });
+
+  for (var visit of gVisits) {
+    if (visit.transition == TRANSITION_TYPED) {
+      PlacesUtils.history.markPageAsTyped(uri(visit.url));
+    } else if (visit.transition == TRANSITION_BOOKMARK) {
+      PlacesUtils.history.markPageAsFollowedBookmark(uri(visit.url));
+    } else {
+      // because it is a top level visit with no referrer,
+      // it will result in TRANSITION_LINK
+    }
+    await PlacesTestUtils.addVisits({
+      uri: uri(visit.url),
+      transition: visit.transition,
+    });
+  }
+
+  await completionPromise;
+});
diff --git a/toolkit/components/places/tests/unit/test_metadata.js b/toolkit/components/places/tests/unit/test_metadata.js
new file mode 100644
index 0000000000..26399f7274
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_metadata.js
@@ -0,0 +1,285 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function test_metadata() {
+  await PlacesUtils.metadata.set("test/integer", 123);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/integer"),
+    123,
+    "Should store new integer value"
+  );
+
+  await PlacesUtils.metadata.set("test/double", 123.45);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/double"),
+    123.45,
+    "Should store new double value"
+  );
+  await PlacesUtils.metadata.set("test/double", 567.89);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/double"),
+    567.89,
+    "Should update existing double value"
+  );
+
+  await PlacesUtils.metadata.set("test/boolean", false);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/boolean"),
+    false,
+    "Should store new Boolean value"
+  );
+  await PlacesUtils.metadata.set("test/boolean", true);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/boolean"),
+    true,
+    "Should update existing Boolean value"
+  );
+
+  await PlacesUtils.metadata.set("test/string", "hi");
+  Assert.equal(
+    await PlacesUtils.metadata.get("test/string"),
+    "hi",
+    "Should store new string value"
+  );
+  await PlacesUtils.metadata.cache.clear();
+  Assert.equal(
+    await PlacesUtils.metadata.get("test/string"),
+    "hi",
+    "Should return string value after clearing cache"
+  );
+
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/nonexistent"),
+    /No data stored for key test\/nonexistent/,
+    "Should reject for a non-existent key and no default value."
+  );
+  Assert.equal(
+    await PlacesUtils.metadata.get("test/nonexistent", "defaultValue"),
+    "defaultValue",
+    "Should return the default value for a non-existent key."
+  );
+
+  // Values are untyped; it's OK to store a value of a different type for the
+  // same key.
+  await PlacesUtils.metadata.set("test/string", 111);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/string"),
+    111,
+    "Should replace string with integer"
+  );
+  await PlacesUtils.metadata.set("test/string", null);
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/string"),
+    /No data stored for key test\/string/,
+    "Should clear value when setting to NULL"
+  );
+
+  await PlacesUtils.metadata.delete("test/string", "test/boolean");
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/string"),
+    /No data stored for key test\/string/,
+    "Should delete string value"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/boolean"),
+    /No data stored for key test\/boolean/,
+    "Should delete Boolean value"
+  );
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("test/integer"),
+    123,
+    "Should keep undeleted integer value"
+  );
+
+  await PlacesTestUtils.clearMetadata();
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/integer"),
+    /No data stored for key test\/integer/,
+    "Should clear integer value"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/double"),
+    /No data stored for key test\/double/,
+    "Should clear double value"
+  );
+});
+
+add_task(async function test_metadata_canonical_keys() {
+  await PlacesUtils.metadata.set("Test/Integer", 123);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("tEsT/integer"),
+    123,
+    "New keys should be case-insensitive"
+  );
+  await PlacesUtils.metadata.set("test/integer", 456);
+  Assert.strictEqual(
+    await PlacesUtils.metadata.get("TEST/INTEGER"),
+    456,
+    "Existing keys should be case-insensitive"
+  );
+
+  await Assert.rejects(
+    PlacesUtils.metadata.set("", 123),
+    /Invalid metadata key/,
+    "Should reject empty keys"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.get(123),
+    /Invalid metadata key/,
+    "Should reject numeric keys"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.delete(true),
+    /Invalid metadata key/,
+    "Should reject Boolean keys"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.set({}),
+    /Invalid metadata key/,
+    "Should reject object keys"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.get(null),
+    /Invalid metadata key/,
+    "Should reject null keys"
+  );
+  await Assert.rejects(
+    PlacesUtils.metadata.delete("!@#$"),
+    /Invalid metadata key/,
+    "Should reject keys with invalid characters"
+  );
+});
+
+add_task(async function test_metadata_blobs() {
+  let blob = new Uint8Array([1, 2, 3]);
+  await PlacesUtils.metadata.set("test/blob", blob);
+
+  let sameBlob = await PlacesUtils.metadata.get("test/blob");
+  Assert.equal(
+    ChromeUtils.getClassName(sameBlob),
+    "Uint8Array",
+    "Should cache typed array for blob value"
+  );
+  Assert.deepEqual(sameBlob, blob, "Should store new blob value");
+
+  info("Remove blob from cache");
+  await PlacesUtils.metadata.cache.clear();
+
+  let newBlob = await PlacesUtils.metadata.get("test/blob");
+  Assert.equal(
+    ChromeUtils.getClassName(newBlob),
+    "Uint8Array",
+    "Should inflate blob into typed array"
+  );
+  Assert.deepEqual(
+    newBlob,
+    blob,
+    "Should return same blob after clearing cache"
+  );
+
+  await PlacesTestUtils.clearMetadata();
+});
+
+add_task(async function test_metadata_arrays() {
+  let array = [1, 2, 3, "\u2713 \u00E0 la mode"];
+  await PlacesUtils.metadata.set("test/array", array);
+
+  let sameArray = await PlacesUtils.metadata.get("test/array");
+  Assert.ok(Array.isArray(sameArray), "Should cache array for array value");
+  Assert.deepEqual(sameArray, array, "Should store new array value");
+
+  info("Remove array from cache");
+  await PlacesUtils.metadata.cache.clear();
+
+  let newArray = await PlacesUtils.metadata.get("test/array");
+  Assert.ok(Array.isArray(newArray), "Should inflate into array");
+  Assert.deepEqual(
+    newArray,
+    array,
+    "Should return same array after clearing cache"
+  );
+
+  await PlacesTestUtils.clearMetadata();
+});
+
+add_task(async function test_metadata_objects() {
+  let object = { foo: 123, bar: "test", meow: "\u2713 \u00E0 la mode" };
+  await PlacesUtils.metadata.set("test/object", object);
+
+  let sameObject = await PlacesUtils.metadata.get("test/object");
+  Assert.equal(
+    typeof sameObject,
+    "object",
+    "Should cache object for object value"
+  );
+  Assert.deepEqual(sameObject, object, "Should store new object value");
+
+  info("Remove object from cache");
+  await PlacesUtils.metadata.cache.clear();
+
+  let newObject = await PlacesUtils.metadata.get("test/object");
+  Assert.equal(typeof newObject, "object", "Should inflate into object");
+  Assert.deepEqual(
+    newObject,
+    object,
+    "Should return same object after clearing cache"
+  );
+
+  await PlacesTestUtils.clearMetadata();
+});
+
+add_task(async function test_metadata_unparsable() {
+  await PlacesUtils.withConnectionWrapper("test_medata", db => {
+    let data = PlacesUtils.metadata._base64Encode("{hjjkhj}");
+
+    return db.execute(`
+      INSERT INTO moz_meta (key, value)
+      VALUES ("test/unparsable", "data:application/json;base64,${data}")
+    `);
+  });
+
+  await Assert.rejects(
+    PlacesUtils.metadata.get("test/unparsable"),
+    /SyntaxError: JSON.parse/,
+    "Should reject for an unparsable value with no default"
+  );
+  Assert.deepEqual(
+    await PlacesUtils.metadata.get("test/unparsable", { foo: 1 }),
+    { foo: 1 },
+    "Should return the default when encountering an unparsable value."
+  );
+
+  await PlacesTestUtils.clearMetadata();
+});
+
+add_task(async function test_metadata_setMany() {
+  await PlacesUtils.metadata.setMany(
+    new Map([
+      ["test/string", "hi"],
+      ["test/boolean", true],
+    ])
+  );
+  await PlacesUtils.metadata.set("test/string", "hi");
+  Assert.deepEqual(
+    await PlacesUtils.metadata.get("test/string"),
+    "hi",
+    "Should store new string value"
+  );
+  Assert.deepEqual(
+    await PlacesUtils.metadata.get("test/boolean"),
+    true,
+    "Should store new boolean value"
+  );
+  await PlacesUtils.metadata.cache.clear();
+  Assert.equal(
+    await PlacesUtils.metadata.get("test/string"),
+    "hi",
+    "Should return string value after clearing cache"
+  );
+  Assert.deepEqual(
+    await PlacesUtils.metadata.get("test/boolean"),
+    true,
+    "Should store new boolean value"
+  );
+  await PlacesTestUtils.clearMetadata();
+});
diff --git a/toolkit/components/places/tests/unit/test_missing_builtin_folders.js b/toolkit/components/places/tests/unit/test_missing_builtin_folders.js
new file mode 100644
index 0000000000..a7d36d27da
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_missing_builtin_folders.js
@@ -0,0 +1,112 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * This file tests that a missing built-in folders (child of root) are correctly
+ * fixed when the database is loaded.
+ */
+
+const ALL_ROOT_GUIDS = [
+  PlacesUtils.bookmarks.menuGuid,
+  PlacesUtils.bookmarks.unfiledGuid,
+  PlacesUtils.bookmarks.toolbarGuid,
+  PlacesUtils.bookmarks.tagsGuid,
+  PlacesUtils.bookmarks.mobileGuid,
+];
+
+add_task(async function setup() {
+  await setupPlacesDatabase([
+    "migration",
+    `places_v${Ci.nsINavHistoryService.DATABASE_SCHEMA_VERSION}.sqlite`,
+  ]);
+
+  // Prepare database contents by removing the tolbar and mobile folders.
+  let path = PathUtils.join(PathUtils.profileDir, DB_FILENAME);
+  let db = await Sqlite.openConnection({ path });
+  await db.execute(
+    `
+    DELETE FROM moz_bookmarks WHERE guid IN(:toolbar, :mobile)
+    `,
+    {
+      toolbar: PlacesUtils.bookmarks.toolbarGuid,
+      mobile: PlacesUtils.bookmarks.mobileGuid,
+    }
+  );
+  await db.close();
+});
+
+add_task(async function test_database_recreates_roots() {
+  Assert.ok(
+    PlacesUtils.history.databaseStatus ==
+      PlacesUtils.history.DATABASE_STATUS_OK ||
+      PlacesUtils.history.databaseStatus ==
+        PlacesUtils.history.DATABASE_STATUS_UPGRADED,
+    "Should successfully access the database for the first time"
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rootId = await PlacesTestUtils.promiseItemId(
+    PlacesUtils.bookmarks.rootGuid
+  );
+  for (let guid of ALL_ROOT_GUIDS) {
+    let rows = await db.execute(
+      `
+      SELECT id, parent FROM moz_bookmarks
+      WHERE guid = :guid
+    `,
+      { guid }
+    );
+
+    Assert.equal(rows.length, 1, "Should have exactly one row for the root");
+
+    Assert.equal(
+      rows[0].getResultByName("parent"),
+      rootId,
+      "Should have been created with the correct parent"
+    );
+
+    let root = await PlacesUtils.bookmarks.fetch(guid);
+
+    Assert.equal(root.guid, guid, "GUIDs should match");
+    Assert.equal(
+      root.parentGuid,
+      PlacesUtils.bookmarks.rootGuid,
+      "Should have the correct parent GUID"
+    );
+    Assert.equal(
+      root.type,
+      PlacesUtils.bookmarks.TYPE_FOLDER,
+      "Should have the correct type"
+    );
+
+    let id = rows[0].getResultByName("id");
+    Assert.equal(
+      await PlacesTestUtils.promiseItemId(guid),
+      id,
+      "Should return the correct id from promiseItemId"
+    );
+    Assert.equal(
+      await PlacesTestUtils.promiseItemGuid(id),
+      guid,
+      "Should return the correct guid from promiseItemGuid"
+    );
+  }
+
+  let rows = await db.execute(
+    `
+    SELECT 1 FROM moz_bookmarks
+    WHERE parent = (SELECT id from moz_bookmarks WHERE guid = :guid)
+  `,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+    }
+  );
+
+  Assert.equal(
+    rows.length,
+    ALL_ROOT_GUIDS.length,
+    "Root folder should have the expected number of children"
+  );
+});
diff --git a/toolkit/components/places/tests/unit/test_missing_root_folder.js b/toolkit/components/places/tests/unit/test_missing_root_folder.js
new file mode 100644
index 0000000000..59f8814d03
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_missing_root_folder.js
@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * This file tests that a missing root folder is correctly fixed when the
+ * database is loaded.
+ */
+
+const ALL_ROOT_GUIDS = [
+  PlacesUtils.bookmarks.menuGuid,
+  PlacesUtils.bookmarks.unfiledGuid,
+  PlacesUtils.bookmarks.toolbarGuid,
+  PlacesUtils.bookmarks.tagsGuid,
+  PlacesUtils.bookmarks.mobileGuid,
+];
+
+add_task(async function setup() {
+  await setupPlacesDatabase([
+    "migration",
+    `places_v${Ci.nsINavHistoryService.DATABASE_SCHEMA_VERSION}.sqlite`,
+  ]);
+
+  // Prepare database contents by removing the root folder.
+  let path = PathUtils.join(PathUtils.profileDir, DB_FILENAME);
+  let db = await Sqlite.openConnection({ path });
+  await db.execute(
+    `
+    DELETE FROM moz_bookmarks WHERE guid = :guid
+    `,
+    {
+      guid: PlacesUtils.bookmarks.rootGuid,
+    }
+  );
+  await db.close();
+});
+
+add_task(async function test_database_recreates_roots() {
+  Assert.ok(
+    PlacesUtils.history.databaseStatus ==
+      PlacesUtils.history.DATABASE_STATUS_OK ||
+      PlacesUtils.history.databaseStatus ==
+        PlacesUtils.history.DATABASE_STATUS_UPGRADED,
+    "Should successfully access the database for the first time"
+  );
+
+  let db = await PlacesUtils.promiseDBConnection();
+
+  let rows = await db.execute(
+    `
+    SELECT id, parent, type FROM moz_bookmarks
+    WHERE guid = :guid
+  `,
+    { guid: PlacesUtils.bookmarks.rootGuid }
+  );
+
+  Assert.equal(rows.length, 1, "Should have added exactly one root");
+  Assert.greaterOrEqual(
+    rows[0].getResultByName("id"),
+    1,
+    "Should have a valid root Id"
+  );
+  Assert.equal(
+    rows[0].getResultByName("parent"),
+    0,
+    "Should have a parent of id 0"
+  );
+  Assert.equal(
+    rows[0].getResultByName("type"),
+    PlacesUtils.bookmarks.TYPE_FOLDER,
+    "Should have a type of folder"
+  );
+
+  let id = rows[0].getResultByName("id");
+  Assert.equal(
+    await PlacesTestUtils.promiseItemId(PlacesUtils.bookmarks.rootGuid),
+    id,
+    "Should return the correct id from promiseItemId"
+  );
+  Assert.equal(
+    await PlacesTestUtils.promiseItemGuid(id),
+    PlacesUtils.bookmarks.rootGuid,
+    "Should return the correct guid from promiseItemGuid"
+  );
+
+  // Note: Currently we do not fix the parent of the folders on initial startup.
+  // There is a maintenance task that will do it, hence we don't check the parents
+  // here, just that the built-in folders correctly exist and haven't been
+  // duplicated.
+  for (let guid of ALL_ROOT_GUIDS) {
+    rows = await db.execute(
+      `
+      SELECT id FROM moz_bookmarks
+      WHERE guid = :guid
+    `,
+      { guid }
+    );
+
+    Assert.equal(rows.length, 1, "Should have exactly one row for the root");
+
+    let root = await PlacesUtils.bookmarks.fetch(guid);
+
+    Assert.equal(root.guid, guid, "GUIDs should match");
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_multi_observation.js b/toolkit/components/places/tests/unit/test_multi_observation.js
new file mode 100644
index 0000000000..d56eabf8f1
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_multi_observation.js
@@ -0,0 +1,384 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test whether registered listener capture proper events.
+// We test the following combinations.
+// * Listener: listen to single/multi event(s)
+// * Event: fire single/multi type of event(s)
+// * Timing: fire event(s) at same time/separately
+// And also test notifying empty events.
+
+add_task(async () => {
+  info("Test for listening to single event and firing single event");
+
+  const observer = startObservation(["page-visited"]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "test",
+      url: "http://example.com/test",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/test",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async () => {
+  info("Test for listening to multi events with firing single event");
+
+  const observer = startObservation(["page-visited", "page-title-changed"]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "test",
+      url: "http://example.com/test",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/test",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async () => {
+  info(
+    "Test for listening to single event with firing multi events at same time"
+  );
+
+  const vistedObserver = startObservation(["page-visited"]);
+  const titleChangedObserver = startObservation(["page-title-changed"]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "will change",
+      url: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+    {
+      title: "changed",
+      url: "http://example.com/title",
+      referrer: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+    {
+      title: "another",
+      url: "http://example.com/another",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedVisitedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+      {
+        type: "page-visited",
+        url: "http://example.com/another",
+      },
+    ],
+  ];
+  assertFiredEvents(vistedObserver.firedEvents, expectedVisitedFiredEvents);
+
+  const expectedTitleChangedFiredEvents = [
+    [
+      {
+        type: "page-title-changed",
+        url: "http://example.com/title",
+        title: "changed",
+      },
+    ],
+  ];
+  assertFiredEvents(
+    titleChangedObserver.firedEvents,
+    expectedTitleChangedFiredEvents
+  );
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async () => {
+  info(
+    "Test for listening to single event with firing multi events separately"
+  );
+
+  const observer = startObservation(["page-visited"]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "test",
+      url: "http://example.com/test",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "another",
+      url: "http://example.com/another",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/test",
+      },
+    ],
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/another",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+});
+
+add_task(async () => {
+  info("Test for listening to multi events with firing single event");
+
+  const observer = startObservation([
+    "page-visited",
+    "page-title-changed",
+    "bookmark-added",
+  ]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "test",
+      url: "http://example.com/test",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/test",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async () => {
+  info(
+    "Test for listening to multi events with firing multi events at same time"
+  );
+
+  const observer = startObservation([
+    "page-visited",
+    "page-title-changed",
+    "bookmark-added",
+  ]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "will change",
+      url: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+    {
+      title: "changed",
+      url: "http://example.com/title",
+      referrer: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+    {
+      title: "another",
+      url: "http://example.com/another",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+      {
+        type: "page-title-changed",
+        url: "http://example.com/title",
+        title: "changed",
+      },
+      {
+        type: "page-visited",
+        url: "http://example.com/another",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async () => {
+  info(
+    "Test for listening to multi events with firing multi events separately"
+  );
+
+  const observer = startObservation([
+    "page-visited",
+    "page-title-changed",
+    "bookmark-added",
+  ]);
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "will change",
+      url: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "a folder",
+  });
+
+  await PlacesUtils.history.insertMany([
+    {
+      title: "changed",
+      url: "http://example.com/title",
+      referrer: "http://example.com/title",
+      visits: [{ transition: TRANSITION_LINK }],
+    },
+  ]);
+
+  const expectedFiredEvents = [
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+    ],
+    [
+      {
+        type: "bookmark-added",
+        title: "a folder",
+      },
+    ],
+    [
+      {
+        type: "page-visited",
+        url: "http://example.com/title",
+      },
+      {
+        type: "page-title-changed",
+        url: "http://example.com/title",
+        title: "changed",
+      },
+    ],
+  ];
+  assertFiredEvents(observer.firedEvents, expectedFiredEvents);
+
+  await PlacesUtils.history.clear();
+  await PlacesUtils.bookmarks.remove(bookmark.guid);
+});
+
+add_task(async function test_empty_notifications_array() {
+  info("Test whether listener does not receive empty events");
+
+  if (AppConstants.DEBUG) {
+    info(
+      "Ignore this test since we added a MOZ_ASSERT for empty events in debug build"
+    );
+    return;
+  }
+
+  const observer = startObservation(["page-visited"]);
+  PlacesObservers.notifyListeners([]);
+  Assert.equal(observer.firedEvents.length, 0, "Listener does not receive any");
+});
+
+function startObservation(targets) {
+  const observer = {
+    firedEvents: [],
+    handle(events) {
+      this.firedEvents.push(events);
+    },
+  };
+
+  PlacesObservers.addListener(targets, observer.handle.bind(observer));
+
+  return observer;
+}
+
+function assertFiredEvents(firedEvents, expectedFiredEvents) {
+  Assert.equal(
+    firedEvents.length,
+    expectedFiredEvents.length,
+    "Number events fired is correct"
+  );
+
+  for (let i = 0; i < firedEvents.length; i++) {
+    info(`Check firedEvents[${i}]`);
+    const events = firedEvents[i];
+    const expectedEvents = expectedFiredEvents[i];
+    assertEvents(events, expectedEvents);
+  }
+}
+
+function assertEvents(events, expectedEvents) {
+  Assert.equal(
+    events.length,
+    expectedEvents.length,
+    "Number events is correct"
+  );
+
+  for (let i = 0; i < events.length; i++) {
+    info(`Check events[${i}]`);
+    const event = events[i];
+    const expectedEvent = expectedEvents[i];
+
+    for (let field in expectedEvent) {
+      Assert.equal(event[field], expectedEvent[field], `${field} is correct`);
+    }
+  }
+}
diff --git a/toolkit/components/places/tests/unit/test_multi_word_tags.js b/toolkit/components/places/tests/unit/test_multi_word_tags.js
new file mode 100644
index 0000000000..17a68cf972
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_multi_word_tags.js
@@ -0,0 +1,147 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Get history service
+try {
+  var histsvc = Cc["@mozilla.org/browser/nav-history-service;1"].getService(
+    Ci.nsINavHistoryService
+  );
+} catch (ex) {
+  do_throw("Could not get history service\n");
+}
+
+// Get tagging service
+try {
+  var tagssvc = Cc["@mozilla.org/browser/tagging-service;1"].getService(
+    Ci.nsITaggingService
+  );
+} catch (ex) {
+  do_throw("Could not get tagging service\n");
+}
+
+add_task(async function run_test() {
+  var uri1 = uri("http://site.tld/1");
+  var uri2 = uri("http://site.tld/2");
+  var uri3 = uri("http://site.tld/3");
+  var uri4 = uri("http://site.tld/4");
+  var uri5 = uri("http://site.tld/5");
+  var uri6 = uri("http://site.tld/6");
+
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      { url: uri1 },
+      { url: uri2 },
+      { url: uri3 },
+      { url: uri4 },
+      { url: uri5 },
+      { url: uri6 },
+    ],
+  });
+
+  tagssvc.tagURI(uri1, ["foo"]);
+  tagssvc.tagURI(uri2, ["bar"]);
+  tagssvc.tagURI(uri3, ["cheese"]);
+  tagssvc.tagURI(uri4, ["foo bar"]);
+  tagssvc.tagURI(uri5, ["bar cheese"]);
+  tagssvc.tagURI(uri6, ["foo bar cheese"]);
+
+  // Search for "item", should get one result
+  var options = histsvc.getNewQueryOptions();
+  options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
+
+  var query = histsvc.getNewQuery();
+  query.searchTerms = "foo";
+  var result = histsvc.executeQuery(query, options);
+  var root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 3);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/1");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/4");
+  Assert.equal(root.getChild(2).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "bar";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 4);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/2");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/4");
+  Assert.equal(root.getChild(2).uri, "http://site.tld/5");
+  Assert.equal(root.getChild(3).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "cheese";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 3);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/3");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/5");
+  Assert.equal(root.getChild(2).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "foo bar";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/4");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "bar foo";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/4");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "bar cheese";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/5");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "cheese bar";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/5");
+  Assert.equal(root.getChild(1).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "foo bar cheese";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "cheese foo bar";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/6");
+  root.containerOpen = false;
+
+  query.searchTerms = "cheese bar foo";
+  result = histsvc.executeQuery(query, options);
+  root = result.root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  Assert.equal(root.getChild(0).uri, "http://site.tld/6");
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_nested_notifications.js b/toolkit/components/places/tests/unit/test_nested_notifications.js
new file mode 100644
index 0000000000..35bcd043d7
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_nested_notifications.js
@@ -0,0 +1,186 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test for nested notifications of Places events.
+ * In this test, we check behavior of listeners of Places event upon firing nested
+ * notification from inside of listener that received notifications.
+ */
+add_task(async function () {
+  // We prepare 6 listeners for the test.
+  // 1. Listener that added before root notification.
+  const addRoot = new Observer();
+  // 2. Listener that added before root notification
+  //    but removed before first nest notification.
+  const addRootRemoveFirst = new Observer();
+  // 3. Listener that added before root notification
+  //    but removed before second nest notification.
+  const addRootRemoveSecond = new Observer();
+  // 4. Listener that added before first nest notification.
+  const addFirst = new Observer();
+  // 5. Listener that added before first nest notification
+  //    but removed before second nest notification.
+  const addFirstRemoveSecond = new Observer();
+  // 6. Listener that added before second nest notification.
+  const addSecond = new Observer();
+
+  // This is a listener listened the root notification
+  // and do what we have to do for test in the first nest.
+  const firstNestOperator = () => {
+    info("Start to operate at first nest");
+
+    // Remove itself to avoid listening more.
+    removePlacesListener(firstNestOperator);
+
+    info("Add/Remove test listeners at first nest");
+    removePlacesListener(addRootRemoveFirst.handle);
+    addPlacesListener(addFirst.handle);
+    addPlacesListener(addFirstRemoveSecond.handle);
+
+    // Add second nest operator.
+    addPlacesListener(secondNestOperator);
+
+    info("Send notification at first nest");
+    notifyPlacesEvent("first");
+  };
+
+  // This is a listener listened the first nest notification
+  // and do what we have to do for test in the second nest.
+  const secondNestOperator = () => {
+    info("Start to operate at second nest");
+
+    // Remove itself to avoid listening more.
+    removePlacesListener(secondNestOperator);
+
+    info("Add/Remove test listeners at second nest");
+    removePlacesListener(addRootRemoveSecond.handle);
+    removePlacesListener(addFirstRemoveSecond.handle);
+    addPlacesListener(addSecond.handle);
+
+    info("Send notification at second nest");
+    notifyPlacesEvent("second");
+  };
+
+  info("Add test listeners that handle notification sent at root");
+  addPlacesListener(addRoot.handle);
+  addPlacesListener(addRootRemoveFirst.handle);
+  addPlacesListener(addRootRemoveSecond.handle);
+
+  // Add first nest operator.
+  addPlacesListener(firstNestOperator);
+
+  info("Send notification at root");
+  notifyPlacesEvent("root");
+
+  info("Check whether or not test listeners could get expected notifications");
+  assertNotifications(addRoot.notifications, [
+    [{ guid: "root" }],
+    [{ guid: "first" }],
+    [{ guid: "second" }],
+  ]);
+  assertNotifications(addRootRemoveFirst.notifications, [[{ guid: "root" }]]);
+  assertNotifications(addRootRemoveSecond.notifications, [
+    [{ guid: "root" }],
+    [{ guid: "first" }],
+  ]);
+  assertNotifications(addFirst.notifications, [
+    [{ guid: "first" }],
+    [{ guid: "second" }],
+  ]);
+  assertNotifications(addFirstRemoveSecond.notifications, [
+    [{ guid: "first" }],
+  ]);
+  assertNotifications(addSecond.notifications, [[{ guid: "second" }]]);
+});
+
+function addPlacesListener(listener) {
+  PlacesObservers.addListener(["bookmark-added"], listener);
+}
+
+function removePlacesListener(listener) {
+  PlacesObservers.removeListener(["bookmark-added"], listener);
+}
+
+function notifyPlacesEvent(guid) {
+  PlacesObservers.notifyListeners([
+    new PlacesBookmarkAddition({
+      dateAdded: 0,
+      guid,
+      id: -1,
+      index: 0,
+      isTagging: false,
+      itemType: 1,
+      parentGuid: "fake",
+      parentId: -2,
+      source: 0,
+      title: guid,
+      tags: "tags",
+      url: `http://example.com/${guid}`,
+      frecency: 0,
+      hidden: false,
+      visitCount: 0,
+      lastVisitDate: 0,
+      targetFolderGuid: null,
+      targetFolderItemId: -1,
+      targetFolderTitle: null,
+    }),
+  ]);
+}
+
+class Observer {
+  constructor() {
+    this.notifications = [];
+    this.handle = this.handle.bind(this);
+  }
+
+  handle(events) {
+    this.notifications.push(events);
+  }
+}
+
+/**
+ * Assert notifications the observer received.
+ *
+ * @param Array - notifications
+ * @param Array - expectedNotifications
+ */
+function assertNotifications(notifications, expectedNotifications) {
+  Assert.equal(
+    notifications.length,
+    expectedNotifications.length,
+    "Number of notifications is correct"
+  );
+
+  for (let i = 0; i < notifications.length; i++) {
+    info(`Check notifications[${i}]`);
+    const placesEvents = notifications[i];
+    const expectedPlacesEvents = expectedNotifications[i];
+    assertPlacesEvents(placesEvents, expectedPlacesEvents);
+  }
+}
+
+/**
+ * Assert Places events.
+ * This function checks given expected event field only.
+ *
+ * @param Array - events
+ * @param Array - expectedEvents
+ */
+function assertPlacesEvents(events, expectedEvents) {
+  Assert.equal(
+    events.length,
+    expectedEvents.length,
+    "Number of Places events is correct"
+  );
+
+  for (let i = 0; i < events.length; i++) {
+    info(`Check Places events[${i}]`);
+    const event = events[i];
+    const expectedEvent = expectedEvents[i];
+
+    for (let field in expectedEvent) {
+      Assert.equal(event[field], expectedEvent[field], `${field} is correct`);
+    }
+  }
+}
diff --git a/toolkit/components/places/tests/unit/test_nsINavHistoryViewer.js b/toolkit/components/places/tests/unit/test_nsINavHistoryViewer.js
new file mode 100644
index 0000000000..e98cdbac79
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_nsINavHistoryViewer.js
@@ -0,0 +1,284 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var resultObserver = {
+  insertedNode: null,
+  nodeInserted(parent, node, newIndex) {
+    this.insertedNode = node;
+  },
+  removedNode: null,
+  nodeRemoved(parent, node, oldIndex) {
+    this.removedNode = node;
+  },
+
+  newTitle: "",
+  nodeChangedByTitle: null,
+  nodeTitleChanged(node, newTitle) {
+    this.nodeChangedByTitle = node;
+    this.newTitle = newTitle;
+  },
+
+  newAccessCount: 0,
+  newTime: 0,
+  nodeChangedByHistoryDetails: null,
+  nodeHistoryDetailsChanged(node, oldVisitDate, oldVisitCount) {
+    this.nodeChangedByHistoryDetails = node;
+    this.newTime = node.time;
+    this.newAccessCount = node.accessCount;
+  },
+
+  movedNode: null,
+  nodeMoved(node, oldParent, oldIndex, newParent, newIndex) {
+    this.movedNode = node;
+  },
+  openedContainer: null,
+  closedContainer: null,
+  containerStateChanged(aNode, aOldState, aNewState) {
+    if (aNewState == Ci.nsINavHistoryContainerResultNode.STATE_OPENED) {
+      this.openedContainer = aNode;
+    } else if (aNewState == Ci.nsINavHistoryContainerResultNode.STATE_CLOSED) {
+      this.closedContainer = aNode;
+    }
+  },
+  invalidatedContainer: null,
+  invalidateContainer(node) {
+    this.invalidatedContainer = node;
+  },
+  sortingMode: null,
+  sortingChanged(sortingMode) {
+    this.sortingMode = sortingMode;
+  },
+  inBatchMode: false,
+  batchingCallCount: 0,
+  batching(aToggleMode) {
+    Assert.notEqual(this.inBatchMode, aToggleMode);
+    this.inBatchMode = aToggleMode;
+    this.batchingCallCount++;
+  },
+  result: null,
+  reset() {
+    this.insertedNode = null;
+    this.removedNode = null;
+    this.nodeChangedByTitle = null;
+    this.nodeChangedByHistoryDetails = null;
+    this.replacedNode = null;
+    this.movedNode = null;
+    this.openedContainer = null;
+    this.closedContainer = null;
+    this.invalidatedContainer = null;
+    this.sortingMode = null;
+    this.inBatchMode = false;
+    this.batchingCallCount = 0;
+  },
+};
+
+var testURI = uri("http://mozilla.com");
+
+add_task(async function check_history_query() {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  options.sortingMode = options.SORT_BY_DATE_DESCENDING;
+  options.resultType = options.RESULTS_AS_VISIT;
+  let query = PlacesUtils.history.getNewQuery();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  result.addObserver(resultObserver);
+  let root = result.root;
+  root.containerOpen = true;
+
+  Assert.notEqual(resultObserver.openedContainer, null);
+
+  // nsINavHistoryResultObserver.nodeInserted
+  // add a visit
+  await PlacesTestUtils.addVisits(testURI);
+  Assert.equal(testURI.spec, resultObserver.insertedNode.uri);
+
+  // nsINavHistoryResultObserver.nodeHistoryDetailsChanged
+  // adding a visit causes nodeHistoryDetailsChanged for the folder
+  Assert.equal(root.uri, resultObserver.nodeChangedByHistoryDetails.uri);
+
+  // nsINavHistoryResultObserver.itemTitleChanged for a leaf node
+  await PlacesTestUtils.addVisits({ uri: testURI, title: "baz" });
+  Assert.equal(resultObserver.nodeChangedByTitle.title, "baz");
+
+  // nsINavHistoryResultObserver.nodeRemoved
+  let removedURI = uri("http://google.com");
+  await PlacesTestUtils.addVisits(removedURI);
+  await PlacesUtils.history.remove(removedURI);
+  Assert.equal(removedURI.spec, resultObserver.removedNode.uri);
+
+  // nsINavHistoryResultObserver.invalidateContainer
+  await PlacesUtils.history.removeByFilter({ host: "mozilla.com" });
+  // This test is disabled for bug 1089691. It is failing bcause the new API
+  // doesn't send batching notifications and thus the result doesn't invalidate
+  // the whole container.
+  // Assert.equal(root.uri, resultObserver.invalidatedContainer.uri);
+
+  // nsINavHistoryResultObserver.sortingChanged
+  resultObserver.invalidatedContainer = null;
+  result.sortingMode = options.SORT_BY_TITLE_ASCENDING;
+  Assert.equal(resultObserver.sortingMode, options.SORT_BY_TITLE_ASCENDING);
+  Assert.equal(resultObserver.invalidatedContainer, result.root);
+
+  // nsINavHistoryResultObserver.invalidateContainer
+  await PlacesUtils.history.clear();
+  Assert.equal(root.uri, resultObserver.invalidatedContainer.uri);
+
+  root.containerOpen = false;
+  Assert.equal(resultObserver.closedContainer, resultObserver.openedContainer);
+  result.removeObserver(resultObserver);
+  resultObserver.reset();
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function check_bookmarks_query() {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let query = PlacesUtils.history.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.menuGuid]);
+  let result = PlacesUtils.history.executeQuery(query, options);
+  result.addObserver(resultObserver);
+  let root = result.root;
+  root.containerOpen = true;
+
+  Assert.notEqual(resultObserver.openedContainer, null);
+
+  // nsINavHistoryResultObserver.nodeInserted
+  // add a bookmark
+  let testBookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: testURI,
+    title: "foo",
+  });
+  Assert.equal("foo", resultObserver.insertedNode.title);
+  Assert.equal(testURI.spec, resultObserver.insertedNode.uri);
+
+  // nsINavHistoryResultObserver.nodeHistoryDetailsChanged
+  // adding a visit causes nodeHistoryDetailsChanged for the folder
+  Assert.equal(root.uri, resultObserver.nodeChangedByHistoryDetails.uri);
+
+  // nsINavHistoryResultObserver.nodeTitleChanged for a leaf node
+  await PlacesUtils.bookmarks.update({
+    guid: testBookmark.guid,
+    title: "baz",
+  });
+  Assert.equal(resultObserver.nodeChangedByTitle.title, "baz");
+  Assert.equal(resultObserver.newTitle, "baz");
+
+  let testBookmark2 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://google.com",
+    title: "foo",
+  });
+
+  await PlacesUtils.bookmarks.update({
+    guid: testBookmark2.guid,
+    index: 0,
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+  });
+  Assert.equal(resultObserver.movedNode.bookmarkGuid, testBookmark2.guid);
+
+  // nsINavHistoryResultObserver.nodeRemoved
+  await PlacesUtils.bookmarks.remove(testBookmark2.guid);
+  Assert.equal(testBookmark2.guid, resultObserver.removedNode.bookmarkGuid);
+
+  // XXX nsINavHistoryResultObserver.invalidateContainer
+
+  // nsINavHistoryResultObserver.sortingChanged
+  resultObserver.invalidatedContainer = null;
+  result.sortingMode = Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING;
+  Assert.equal(
+    resultObserver.sortingMode,
+    Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING
+  );
+  Assert.equal(resultObserver.invalidatedContainer, result.root);
+
+  root.containerOpen = false;
+  Assert.equal(resultObserver.closedContainer, resultObserver.openedContainer);
+  result.removeObserver(resultObserver);
+  resultObserver.reset();
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function check_mixed_query() {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let query = PlacesUtils.history.getNewQuery();
+  let result = PlacesUtils.history.executeQuery(query, options);
+  result.addObserver(resultObserver);
+  let root = result.root;
+  root.containerOpen = true;
+
+  Assert.notEqual(resultObserver.openedContainer, null);
+
+  root.containerOpen = false;
+  Assert.equal(resultObserver.closedContainer, resultObserver.openedContainer);
+  result.removeObserver(resultObserver);
+  resultObserver.reset();
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function check_a_batch_process() {
+  const options = PlacesUtils.history.getNewQueryOptions();
+  const query = PlacesUtils.history.getNewQuery();
+  const result = PlacesUtils.history.executeQuery(query, options);
+  result.addObserver(resultObserver);
+
+  info("Check initial state");
+  Assert.equal(resultObserver.inBatchMode, false);
+  Assert.equal(resultObserver.batchingCallCount, 0);
+
+  info("Check whether batching is called when call onBeginUpdateBatch");
+  result.onBeginUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, true);
+  Assert.equal(resultObserver.batchingCallCount, 1);
+
+  info("Check whether batching is called when call onEndUpdateBatch");
+  result.onEndUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, false);
+  Assert.equal(resultObserver.batchingCallCount, 2);
+
+  result.removeObserver(resultObserver);
+  resultObserver.reset();
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
+
+add_task(async function check_multi_batch_processes() {
+  const options = PlacesUtils.history.getNewQueryOptions();
+  const query = PlacesUtils.history.getNewQuery();
+  const result = PlacesUtils.history.executeQuery(query, options);
+  result.addObserver(resultObserver);
+
+  info("Check initial state");
+  Assert.equal(resultObserver.inBatchMode, false);
+  Assert.equal(resultObserver.batchingCallCount, 0);
+
+  info("Check whether batching is called when calling onBeginUpdateBatch");
+  result.onBeginUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, true);
+  Assert.equal(resultObserver.batchingCallCount, 1);
+
+  info(
+    "Check whether batching is not called when calling onBeginUpdateBatch again"
+  );
+  result.onBeginUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, true);
+  Assert.equal(resultObserver.batchingCallCount, 1);
+
+  info(
+    "Check whether batching is not called until calling onEndUpdateBatch the same number times that onBeginUpdateBatch is called"
+  );
+  result.onEndUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, true);
+  Assert.equal(resultObserver.batchingCallCount, 1);
+
+  info(
+    "Check whether batching is called when calling onEndUpdateBatch the same number times"
+  );
+  result.onEndUpdateBatch();
+  Assert.equal(resultObserver.inBatchMode, false);
+  Assert.equal(resultObserver.batchingCallCount, 2);
+
+  result.removeObserver(resultObserver);
+  resultObserver.reset();
+  await PlacesTestUtils.promiseAsyncUpdates();
+});
diff --git a/toolkit/components/places/tests/unit/test_null_interfaces.js b/toolkit/components/places/tests/unit/test_null_interfaces.js
new file mode 100644
index 0000000000..f5608285d6
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_null_interfaces.js
@@ -0,0 +1,105 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test bug 489872 to make sure passing nulls to nsNavHistory doesn't crash.
+ */
+
+// Make an array of services to test, each specifying a class id, interface
+// and an array of function names that don't throw when passed nulls
+var testServices = [
+  [
+    "browser/nav-history-service;1",
+    ["nsINavHistoryService"],
+    [
+      "queryStringToQuery",
+      "removePagesByTimeframe",
+      "removePagesFromHost",
+      "getObservers",
+    ],
+  ],
+  [
+    "browser/nav-bookmarks-service;1",
+    ["nsINavBookmarksService"],
+    ["createFolder", "getObservers"],
+  ],
+  ["browser/favicon-service;1", ["nsIFaviconService"], []],
+  ["browser/tagging-service;1", ["nsITaggingService"], []],
+];
+info(testServices.join("\n"));
+
+function run_test() {
+  for (let [cid, ifaces, nothrow] of testServices) {
+    info(`Running test with ${cid} ${ifaces.join(", ")} ${nothrow}`);
+    let s = Cc["@mozilla.org/" + cid].getService(Ci.nsISupports);
+    for (let iface of ifaces) {
+      s.QueryInterface(Ci[iface]);
+    }
+
+    let okName = function (name) {
+      info(`Checking if function is okay to test: ${name}`);
+      let func = s[name];
+
+      let mesg = "";
+      if (typeof func != "function") {
+        mesg = "Not a function!";
+      } else if (!func.length) {
+        mesg = "No args needed!";
+      } else if (name == "QueryInterface") {
+        mesg = "Ignore QI!";
+      }
+
+      if (mesg) {
+        info(`${mesg} Skipping: ${name}`);
+        return false;
+      }
+
+      return true;
+    };
+
+    info(`Generating an array of functions to test service: ${s}`);
+    for (let n of Object.keys(s)
+      .filter(i => okName(i))
+      .sort()) {
+      info(`\nTesting ${ifaces.join(", ")} function with null args: ${n}`);
+
+      let func = s[n];
+      let num = func.length;
+      info(`Generating array of nulls for #args: ${num}`);
+      let args = Array(num).fill(null);
+
+      let tryAgain = true;
+      while (tryAgain) {
+        try {
+          info(`Calling with args: ${JSON.stringify(args)}`);
+          func.apply(s, args);
+
+          info(
+            `The function did not throw! Is it one of the nothrow? ${nothrow}`
+          );
+          Assert.notEqual(nothrow.indexOf(n), -1);
+
+          info("Must have been an expected nothrow, so no need to try again");
+          tryAgain = false;
+        } catch (ex) {
+          if (ex.result == Cr.NS_ERROR_ILLEGAL_VALUE) {
+            info(`Caught an expected exception: ${ex.name}`);
+            info("Moving on to the next test..");
+            tryAgain = false;
+          } else if (ex.result == Cr.NS_ERROR_XPC_NEED_OUT_OBJECT) {
+            let pos = Number(ex.message.match(/object arg (\d+)/)[1]);
+            info(`Function call expects an out object at ${pos}`);
+            args[pos] = {};
+          } else if (ex.result == Cr.NS_ERROR_NOT_IMPLEMENTED) {
+            info(`Method not implemented exception: ${ex.name}`);
+            info("Moving on to the next test..");
+            tryAgain = false;
+          } else {
+            throw ex;
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/toolkit/components/places/tests/unit/test_origins.js b/toolkit/components/places/tests/unit/test_origins.js
new file mode 100644
index 0000000000..67b6d59c7d
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_origins.js
@@ -0,0 +1,1113 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Makes sure the moz_origins table and origin frecency stats are updated
+// correctly.
+
+"use strict";
+
+// Visiting a URL with a new origin should immediately update moz_origins.
+add_task(async function visit() {
+  await checkDB([]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Repeatedly visiting a URL with an initially new origin should update
+// moz_origins (with the correct frecency).
+add_task(async function visitRepeatedly() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://example.com/" },
+    { uri: "http://example.com/" },
+  ]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Same as previous, but visits are added sequentially.
+add_task(async function visitRepeatedlySequential() {
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// After removing an origin's URLs, visiting a URL with the origin should
+// immediately update moz_origins.
+add_task(async function vistAfterDelete() {
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Visiting different URLs with the same origin should update moz_origins, and
+// moz_origins.frecency should be the sum of the URL frecencies.
+add_task(async function visitDifferentURLsSameOrigin() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/1" },
+    { uri: "http://example.com/2" },
+    { uri: "http://example.com/3" },
+  ]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/1", "http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/2");
+  await checkDB([["http://", "example.com", ["http://example.com/3"]]]);
+  await PlacesUtils.history.remove("http://example.com/3");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Same as previous, but visits are added sequentially.
+add_task(async function visitDifferentURLsSameOriginSequential() {
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/1" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/1"]]]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/2" }]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/1", "http://example.com/2"],
+    ],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/3" }]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/1", "http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/2");
+  await checkDB([["http://", "example.com", ["http://example.com/3"]]]);
+  await PlacesUtils.history.remove("http://example.com/3");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Repeatedly visiting different URLs with the same origin should update
+// moz_origins (with the correct frecencies), and moz_origins.frecency should be
+// the sum of the URL frecencies.
+add_task(async function visitDifferentURLsSameOriginRepeatedly() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/1" },
+    { uri: "http://example.com/1" },
+    { uri: "http://example.com/1" },
+    { uri: "http://example.com/2" },
+    { uri: "http://example.com/2" },
+    { uri: "http://example.com/3" },
+  ]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/1", "http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/2", "http://example.com/3"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/2");
+  await checkDB([["http://", "example.com", ["http://example.com/3"]]]);
+  await PlacesUtils.history.remove("http://example.com/3");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Visiting URLs with different origins should update moz_origins.
+add_task(async function visitDifferentOrigins() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example1.com/" },
+    { uri: "http://example2.com/" },
+    { uri: "http://example3.com/" },
+  ]);
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/"]],
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/");
+  await checkDB([["http://", "example3.com", ["http://example3.com/"]]]);
+  await PlacesUtils.history.remove("http://example3.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Same as previous, but visits are added sequentially.
+add_task(async function visitDifferentOriginsSequential() {
+  await PlacesTestUtils.addVisits([{ uri: "http://example1.com/" }]);
+  await checkDB([["http://", "example1.com", ["http://example1.com/"]]]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example2.com/" }]);
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/"]],
+    ["http://", "example2.com", ["http://example2.com/"]],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example3.com/" }]);
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/"]],
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/");
+  await checkDB([["http://", "example3.com", ["http://example3.com/"]]]);
+  await PlacesUtils.history.remove("http://example3.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Repeatedly visiting URLs with different origins should update moz_origins
+// (with the correct frecencies).
+add_task(async function visitDifferentOriginsRepeatedly() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example1.com/" },
+    { uri: "http://example1.com/" },
+    { uri: "http://example1.com/" },
+    { uri: "http://example2.com/" },
+    { uri: "http://example2.com/" },
+    { uri: "http://example3.com/" },
+  ]);
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/"]],
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/"]],
+    ["http://", "example3.com", ["http://example3.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/");
+  await checkDB([["http://", "example3.com", ["http://example3.com/"]]]);
+  await PlacesUtils.history.remove("http://example3.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Visiting URLs, some with the same and some with different origins, should
+// update moz_origins.
+add_task(async function visitDifferentOriginsDifferentURLs() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example1.com/1" },
+    { uri: "http://example1.com/2" },
+    { uri: "http://example1.com/3" },
+    { uri: "http://example2.com/1" },
+    { uri: "http://example2.com/2" },
+    { uri: "http://example3.com/1" },
+  ]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      ["http://example1.com/2", "http://example1.com/3"],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/2");
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/3"]],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/3");
+  await checkDB([
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/1");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/2"]],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/2");
+  await checkDB([["http://", "example3.com", ["http://example3.com/1"]]]);
+  await PlacesUtils.history.remove("http://example3.com/1");
+  await checkDB([]);
+});
+
+// Same as previous, but visits are added sequentially.
+add_task(async function visitDifferentOriginsDifferentURLsSequential() {
+  await PlacesTestUtils.addVisits([{ uri: "http://example1.com/1" }]);
+  await checkDB([["http://", "example1.com", ["http://example1.com/1"]]]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example1.com/2" }]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      ["http://example1.com/1", "http://example1.com/2"],
+    ],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example1.com/3" }]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example2.com/1" }]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+    ["http://", "example2.com", ["http://example2.com/1"]],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example2.com/2" }]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+  ]);
+  await PlacesTestUtils.addVisits([{ uri: "http://example3.com/1" }]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      ["http://example1.com/2", "http://example1.com/3"],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/2");
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/3"]],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/3");
+  await checkDB([
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/1");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/2"]],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/2");
+  await checkDB([["http://", "example3.com", ["http://example3.com/1"]]]);
+  await PlacesUtils.history.remove("http://example3.com/1");
+  await checkDB([]);
+});
+
+// Repeatedly visiting URLs, some with the same and some with different origins,
+// should update moz_origins (with the correct frecencies).
+add_task(async function visitDifferentOriginsDifferentURLsRepeatedly() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example1.com/1" },
+    { uri: "http://example1.com/1" },
+    { uri: "http://example1.com/1" },
+    { uri: "http://example1.com/2" },
+    { uri: "http://example1.com/2" },
+    { uri: "http://example1.com/3" },
+    { uri: "http://example2.com/1" },
+    { uri: "http://example2.com/1" },
+    { uri: "http://example2.com/1" },
+    { uri: "http://example2.com/2" },
+    { uri: "http://example2.com/2" },
+    { uri: "http://example3.com/1" },
+    { uri: "http://example3.com/1" },
+  ]);
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      [
+        "http://example1.com/1",
+        "http://example1.com/2",
+        "http://example1.com/3",
+      ],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/1");
+  await checkDB([
+    [
+      "http://",
+      "example1.com",
+      ["http://example1.com/2", "http://example1.com/3"],
+    ],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/2");
+  await checkDB([
+    ["http://", "example1.com", ["http://example1.com/3"]],
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example1.com/3");
+  await checkDB([
+    [
+      "http://",
+      "example2.com",
+      ["http://example2.com/1", "http://example2.com/2"],
+    ],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/1");
+  await checkDB([
+    ["http://", "example2.com", ["http://example2.com/2"]],
+    ["http://", "example3.com", ["http://example3.com/1"]],
+  ]);
+  await PlacesUtils.history.remove("http://example2.com/2");
+  await checkDB([["http://", "example3.com", ["http://example3.com/1"]]]);
+  await PlacesUtils.history.remove("http://example3.com/1");
+  await checkDB([]);
+});
+
+// Makes sure URIs with the same TLD but different www subdomains are recognized
+// as different origins.  Makes sure removing one doesn't remove the others.
+add_task(async function www1() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://www.example.com/" },
+    { uri: "http://www.www.example.com/" },
+  ]);
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+    ["http://", "www.www.example.com", ["http://www.www.example.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+    ["http://", "www.www.example.com", ["http://www.www.example.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://www.example.com/");
+  await checkDB([
+    ["http://", "www.www.example.com", ["http://www.www.example.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://www.www.example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Same as www1, but removes URIs in a different order.
+add_task(async function www2() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://www.example.com/" },
+    { uri: "http://www.www.example.com/" },
+  ]);
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+    ["http://", "www.www.example.com", ["http://www.www.example.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://www.www.example.com/");
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+  ]);
+  await PlacesUtils.history.remove("http://www.example.com/");
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Makes sure removing an origin without a port doesn't remove the same host
+// with a port.
+add_task(async function ports1() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://example.com:8888/" },
+  ]);
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "example.com:8888", ["http://example.com:8888/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([
+    ["http://", "example.com:8888", ["http://example.com:8888/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example.com:8888/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Makes sure removing an origin with a port doesn't remove the same host
+// without a port.
+add_task(async function ports2() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://example.com:8888/" },
+  ]);
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "example.com:8888", ["http://example.com:8888/"]],
+  ]);
+  await PlacesUtils.history.remove("http://example.com:8888/");
+  await checkDB([["http://", "example.com", ["http://example.com/"]]]);
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Makes sure multiple URIs with the same origin don't create duplicate origins.
+add_task(async function duplicates() {
+  await PlacesTestUtils.addVisits([
+    { uri: "http://example.com/" },
+    { uri: "http://www.example.com/" },
+    { uri: "http://www.www.example.com/" },
+    { uri: "https://example.com/" },
+    { uri: "ftp://example.com/" },
+    { uri: "foo://example.com/" },
+    { uri: "bar:example.com/" },
+    { uri: "http://example.com:8888/" },
+
+    { uri: "http://example.com/dupe" },
+    { uri: "http://www.example.com/dupe" },
+    { uri: "http://www.www.example.com/dupe" },
+    { uri: "https://example.com/dupe" },
+    { uri: "ftp://example.com/dupe" },
+    { uri: "foo://example.com/dupe" },
+    { uri: "bar:example.com/dupe" },
+    { uri: "http://example.com:8888/dupe" },
+  ]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/", "http://example.com/dupe"],
+    ],
+    [
+      "http://",
+      "www.example.com",
+      ["http://www.example.com/", "http://www.example.com/dupe"],
+    ],
+    [
+      "http://",
+      "www.www.example.com",
+      ["http://www.www.example.com/", "http://www.www.example.com/dupe"],
+    ],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("http://example.com/");
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/dupe"]],
+    [
+      "http://",
+      "www.example.com",
+      ["http://www.example.com/", "http://www.example.com/dupe"],
+    ],
+    [
+      "http://",
+      "www.www.example.com",
+      ["http://www.www.example.com/", "http://www.www.example.com/dupe"],
+    ],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://example.com/dupe");
+  await checkDB([
+    [
+      "http://",
+      "www.example.com",
+      ["http://www.example.com/", "http://www.example.com/dupe"],
+    ],
+    [
+      "http://",
+      "www.www.example.com",
+      ["http://www.www.example.com/", "http://www.www.example.com/dupe"],
+    ],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("http://www.example.com/");
+  await checkDB([
+    ["http://", "www.example.com", ["http://www.example.com/dupe"]],
+    [
+      "http://",
+      "www.www.example.com",
+      ["http://www.www.example.com/", "http://www.www.example.com/dupe"],
+    ],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://www.example.com/dupe");
+  await checkDB([
+    [
+      "http://",
+      "www.www.example.com",
+      ["http://www.www.example.com/", "http://www.www.example.com/dupe"],
+    ],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("http://www.www.example.com/");
+  await checkDB([
+    ["http://", "www.www.example.com", ["http://www.www.example.com/dupe"]],
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("http://www.www.example.com/dupe");
+  await checkDB([
+    [
+      "https://",
+      "example.com",
+      ["https://example.com/", "https://example.com/dupe"],
+    ],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("https://example.com/");
+  await checkDB([
+    ["https://", "example.com", ["https://example.com/dupe"]],
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("https://example.com/dupe");
+  await checkDB([
+    ["ftp://", "example.com", ["ftp://example.com/", "ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("ftp://example.com/");
+  await checkDB([
+    ["ftp://", "example.com", ["ftp://example.com/dupe"]],
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("ftp://example.com/dupe");
+  await checkDB([
+    ["foo://", "example.com", ["foo://example.com/", "foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("foo://example.com/");
+  await checkDB([
+    ["foo://", "example.com", ["foo://example.com/dupe"]],
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("foo://example.com/dupe");
+  await checkDB([
+    ["bar:", "example.com", ["bar:example.com/", "bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("bar:example.com/");
+  await checkDB([
+    ["bar:", "example.com", ["bar:example.com/dupe"]],
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+  await PlacesUtils.history.remove("bar:example.com/dupe");
+  await checkDB([
+    [
+      "http://",
+      "example.com:8888",
+      ["http://example.com:8888/", "http://example.com:8888/dupe"],
+    ],
+  ]);
+
+  await PlacesUtils.history.remove("http://example.com:8888/");
+  await checkDB([
+    ["http://", "example.com:8888", ["http://example.com:8888/dupe"]],
+  ]);
+  await PlacesUtils.history.remove("http://example.com:8888/dupe");
+  await checkDB([]);
+
+  await cleanUp();
+});
+
+// Makes sure adding and removing bookmarks creates origins.
+add_task(async function addRemoveBookmarks() {
+  let bookmarks = [];
+  let urls = ["http://example.com/", "http://www.example.com/"];
+  for (let url of urls) {
+    bookmarks.push(
+      await PlacesUtils.bookmarks.insert({
+        url,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      })
+    );
+  }
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+  ]);
+  await PlacesUtils.bookmarks.remove(bookmarks[0]);
+  await PlacesUtils.history.clear();
+  await checkDB([["http://", "www.example.com", ["http://www.example.com/"]]]);
+  await PlacesUtils.bookmarks.remove(bookmarks[1]);
+  await PlacesUtils.history.clear();
+  await checkDB([]);
+  await cleanUp();
+});
+
+// Makes sure changing bookmarks also changes the corresponding origins.
+add_task(async function changeBookmarks() {
+  let bookmarks = [];
+  let urls = ["http://example.com/", "http://www.example.com/"];
+  for (let url of urls) {
+    bookmarks.push(
+      await PlacesUtils.bookmarks.insert({
+        url,
+        parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+      })
+    );
+  }
+  await checkDB([
+    ["http://", "example.com", ["http://example.com/"]],
+    ["http://", "www.example.com", ["http://www.example.com/"]],
+  ]);
+  await PlacesUtils.bookmarks.update({
+    url: "http://www.example.com/",
+    guid: bookmarks[0].guid,
+  });
+  await PlacesUtils.history.clear();
+  await checkDB([["http://", "www.example.com", ["http://www.example.com/"]]]);
+  await cleanUp();
+});
+
+// A slightly more complex test to make sure origin frecency stats are updated
+// when visits and bookmarks are added and removed.
+add_task(async function moreOriginFrecencyStats() {
+  await checkDB([]);
+
+  // Add a URL 0 visit.
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/0" }]);
+  await checkDB([["http://", "example.com", ["http://example.com/0"]]]);
+
+  // Add a URL 1 visit.
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/1" }]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1"],
+    ],
+  ]);
+
+  // Add a URL 2 visit.
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/2" }]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1", "http://example.com/2"],
+    ],
+  ]);
+
+  // Add another URL 2 visit.
+  await PlacesTestUtils.addVisits([{ uri: "http://example.com/2" }]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1", "http://example.com/2"],
+    ],
+  ]);
+
+  // Remove URL 2's visits.
+  await PlacesUtils.history.remove(["http://example.com/2"]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1"],
+    ],
+  ]);
+
+  // Bookmark URL 1.
+  let bookmark = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "A bookmark",
+    url: NetUtil.newURI("http://example.com/1"),
+  });
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1"],
+    ],
+  ]);
+
+  // Remove URL 1's visit.
+  await PlacesUtils.history.remove(["http://example.com/1"]);
+  await checkDB([
+    [
+      "http://",
+      "example.com",
+      ["http://example.com/0", "http://example.com/1"],
+    ],
+  ]);
+
+  // Remove URL 1's bookmark.  Also need to call history.remove() again to
+  // remove the URL from moz_places.  Otherwise it sticks around and keeps
+  // contributing to the frecency stats.
+  await PlacesUtils.bookmarks.remove(bookmark);
+  await PlacesUtils.history.remove("http://example.com/1");
+  await checkDB([["http://", "example.com", ["http://example.com/0"]]]);
+
+  // Remove URL 0.
+  await PlacesUtils.history.remove(["http://example.com/0"]);
+  await checkDB([]);
+
+  await cleanUp();
+});
+
+/**
+ * Returns the expected frecency of the origin of the given URLs, i.e., the sum
+ * of their frecencies.  Each URL is expected to have the same origin.
+ *
+ * @param  urls
+ *         An array of URL strings.
+ * @return The expected origin frecency.
+ */
+async function expectedOriginFrecency(urls) {
+  let value = 0;
+  for (let url of urls) {
+    let v = Math.max(
+      await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", { url }),
+      0
+    );
+    value += v;
+  }
+  return value;
+}
+
+/**
+ * Asserts that the moz_origins table and the origin frecency stats are correct.
+ *
+ * @param expectedOrigins
+ *        An array of expected origins.  Each origin in the array is itself an
+ *        array that looks like this:
+ *          [prefix, host, [url1, url2, ..., urln]]
+ *        The element at index 2 is an array of all the URLs with the origin.
+ *        If you don't care about checking frecencies and origin frecency stats,
+ *        this element can be `undefined`.
+ */
+async function checkDB(expectedOrigins) {
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`
+    SELECT prefix, host, frecency
+    FROM moz_origins
+    ORDER BY id ASC
+  `);
+  let checkFrecencies =
+    !expectedOrigins.length || expectedOrigins[0][2] !== undefined;
+  let actualOrigins = rows.map(row => {
+    let o = [];
+    for (let c = 0; c < (checkFrecencies ? 3 : 2); c++) {
+      o.push(row.getResultByIndex(c));
+    }
+    return o;
+  });
+  let expected = [];
+  for (let origin of expectedOrigins) {
+    expected.push(
+      origin
+        .slice(0, 2)
+        .concat(checkFrecencies ? await expectedOriginFrecency(origin[2]) : [])
+    );
+  }
+  Assert.deepEqual(actualOrigins, expected);
+  if (checkFrecencies) {
+    await checkStats(expected.map(o => o[2]).filter(o => o > 0));
+  }
+}
+
+/**
+ * Asserts that the origin frecency stats are correct.
+ *
+ * @param expectedOriginFrecencies
+ *        An array of expected origin frecencies.
+ */
+async function checkStats(expectedOriginFrecencies) {
+  let stats = await promiseStats();
+  Assert.equal(stats.count, expectedOriginFrecencies.length);
+  Assert.equal(
+    stats.sum,
+    expectedOriginFrecencies.reduce((sum, f) => sum + f, 0)
+  );
+  Assert.equal(
+    stats.squares,
+    expectedOriginFrecencies.reduce((squares, f) => squares + f * f, 0)
+  );
+}
+
+/**
+ * Returns the origin frecency stats.
+ *
+ * @return An object: { count, sum, squares }
+ */
+async function promiseStats() {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`
+    SELECT
+      IFNULL((SELECT value FROM moz_meta WHERE key = 'origin_frecency_count'), 0),
+      IFNULL((SELECT value FROM moz_meta WHERE key = 'origin_frecency_sum'), 0),
+      IFNULL((SELECT value FROM moz_meta WHERE key = 'origin_frecency_sum_of_squares'), 0)
+  `);
+  return {
+    count: rows[0].getResultByIndex(0),
+    sum: rows[0].getResultByIndex(1),
+    squares: rows[0].getResultByIndex(2),
+  };
+}
+
+async function cleanUp() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+}
diff --git a/toolkit/components/places/tests/unit/test_origins_parsing.js b/toolkit/components/places/tests/unit/test_origins_parsing.js
new file mode 100644
index 0000000000..35ba8bdd0d
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_origins_parsing.js
@@ -0,0 +1,104 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test is a companion to test_origins.js.  It adds many URLs to the
+// database and makes sure that their prefixes and hosts are correctly parsed.
+// This test can take a while to run, which is why it's split out from
+// test_origins.js.
+
+"use strict";
+
+add_task(async function parsing() {
+  let prefixes = ["http://", "https://", "ftp://", "foo://", "bar:"];
+
+  let userinfos = ["", "user:pass@", "user:pass:word@", "user:@"];
+
+  let ports = ["", ":8888"];
+
+  let paths = [
+    "",
+
+    "/",
+    "/1",
+    "/1/2",
+
+    "?",
+    "?1",
+    "#",
+    "#1",
+
+    "/?",
+    "/1?",
+    "/?1",
+    "/1?2",
+
+    "/#",
+    "/1#",
+    "/#1",
+    "/1#2",
+
+    "/?#",
+    "/1?#",
+    "/?1#",
+    "/?#1",
+    "/1?2#",
+    "/1?#2",
+    "/?1#2",
+  ];
+
+  for (let userinfo of userinfos) {
+    for (let port of ports) {
+      for (let path of paths) {
+        info(`Testing userinfo='${userinfo}' port='${port}' path='${path}'`);
+        let expectedOrigins = prefixes.map(prefix => [
+          prefix,
+          "example.com" + port,
+        ]);
+        let uris = expectedOrigins.map(
+          ([prefix, hostPort]) => prefix + userinfo + hostPort + path
+        );
+
+        await PlacesTestUtils.addVisits(uris.map(uri => ({ uri })));
+        await checkDB(expectedOrigins);
+
+        // Remove each URI, one at a time, and make sure the remaining origins
+        // in the database are correct.
+        for (let i = 0; i < uris.length; i++) {
+          await PlacesUtils.history.remove(uris[i]);
+          await checkDB(expectedOrigins.slice(i + 1, expectedOrigins.length));
+        }
+        await cleanUp();
+      }
+    }
+  }
+  await checkDB([]);
+});
+
+/**
+ * Asserts that the moz_origins table is correct.
+ *
+ * @param expectedOrigins
+ *        An array of expected origins.  Each origin in the array is itself an
+ *        array that looks like this: [prefix, host]
+ */
+async function checkDB(expectedOrigins) {
+  let db = await PlacesUtils.promiseDBConnection();
+  let rows = await db.execute(`
+    SELECT prefix, host
+    FROM moz_origins
+    ORDER BY id ASC
+  `);
+  let actualOrigins = rows.map(row => {
+    let o = [];
+    for (let c = 0; c < 2; c++) {
+      o.push(row.getResultByIndex(c));
+    }
+    return o;
+  });
+  Assert.deepEqual(actualOrigins, expectedOrigins);
+}
+
+async function cleanUp() {
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+}
diff --git a/toolkit/components/places/tests/unit/test_pageGuid_bookmarkGuid.js b/toolkit/components/places/tests/unit/test_pageGuid_bookmarkGuid.js
new file mode 100644
index 0000000000..e1fa64a88c
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_pageGuid_bookmarkGuid.js
@@ -0,0 +1,256 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const histsvc = PlacesUtils.history;
+
+add_task(async function test_addBookmarksAndCheckGuids() {
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "test folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            url: "http://test1.com/",
+            title: "1 title",
+          },
+          {
+            url: "http://test2.com/",
+            title: "2 title",
+          },
+          {
+            url: "http://test3.com/",
+            title: "3 title",
+          },
+          {
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+          },
+          {
+            title: "test folder 2",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+        ],
+      },
+    ],
+  });
+
+  let root = PlacesUtils.getFolderContents(bookmarks[0].guid).root;
+  Assert.equal(root.childCount, 5);
+
+  // check bookmark guids
+  let bookmarkGuidZero = root.getChild(0).bookmarkGuid;
+  Assert.equal(bookmarkGuidZero.length, 12);
+  // bookmarks have bookmark guids
+  Assert.equal(root.getChild(1).bookmarkGuid.length, 12);
+  Assert.equal(root.getChild(2).bookmarkGuid.length, 12);
+  // separator has bookmark guid
+  Assert.equal(root.getChild(3).bookmarkGuid.length, 12);
+  // folder has bookmark guid
+  Assert.equal(root.getChild(4).bookmarkGuid.length, 12);
+  // all bookmark guids are different.
+  Assert.notEqual(bookmarkGuidZero, root.getChild(1).bookmarkGuid);
+  Assert.notEqual(root.getChild(1).bookmarkGuid, root.getChild(2).bookmarkGuid);
+  Assert.notEqual(root.getChild(2).bookmarkGuid, root.getChild(3).bookmarkGuid);
+  Assert.notEqual(root.getChild(3).bookmarkGuid, root.getChild(4).bookmarkGuid);
+
+  // check page guids
+  let pageGuidZero = root.getChild(0).pageGuid;
+  Assert.equal(pageGuidZero.length, 12);
+  // bookmarks have page guids
+  Assert.equal(root.getChild(1).pageGuid.length, 12);
+  Assert.equal(root.getChild(2).pageGuid.length, 12);
+  // folder and separator don't have page guids
+  Assert.equal(root.getChild(3).pageGuid, "");
+  Assert.equal(root.getChild(4).pageGuid, "");
+
+  Assert.notEqual(pageGuidZero, root.getChild(1).pageGuid);
+  Assert.notEqual(root.getChild(1).pageGuid, root.getChild(2).pageGuid);
+
+  root.containerOpen = false;
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_updateBookmarksAndCheckGuids() {
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "test folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            url: "http://test1.com/",
+            title: "1 title",
+          },
+          {
+            title: "test folder 2",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+          },
+        ],
+      },
+    ],
+  });
+
+  let root = PlacesUtils.getFolderContents(bookmarks[0].guid).root;
+  Assert.equal(root.childCount, 2);
+
+  // ensure the bookmark and page guids remain the same after modifing other property.
+  let bookmarkGuidZero = root.getChild(0).bookmarkGuid;
+  let pageGuidZero = root.getChild(0).pageGuid;
+  await PlacesUtils.bookmarks.update({
+    guid: bookmarks[1].guid,
+    title: "1 title mod",
+  });
+  Assert.equal(root.getChild(0).title, "1 title mod");
+  Assert.equal(root.getChild(0).bookmarkGuid, bookmarkGuidZero);
+  Assert.equal(root.getChild(0).pageGuid, pageGuidZero);
+
+  let bookmarkGuidOne = root.getChild(1).bookmarkGuid;
+  let pageGuidOne = root.getChild(1).pageGuid;
+
+  await PlacesUtils.bookmarks.update({
+    guid: bookmarks[2].guid,
+    title: "test foolder 234",
+  });
+  Assert.equal(root.getChild(1).title, "test foolder 234");
+  Assert.equal(root.getChild(1).bookmarkGuid, bookmarkGuidOne);
+  Assert.equal(root.getChild(1).pageGuid, pageGuidOne);
+
+  root.containerOpen = false;
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_addVisitAndCheckGuid() {
+  // add a visit and test page guid and non-existing bookmark guids.
+  let sourceURI = uri("http://test4.com/");
+  await PlacesTestUtils.addVisits({ uri: sourceURI });
+  Assert.equal(await PlacesUtils.bookmarks.fetch({ url: sourceURI }, null));
+
+  let options = histsvc.getNewQueryOptions();
+  let query = histsvc.getNewQuery();
+  query.uri = sourceURI;
+  let root = histsvc.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+
+  do_check_valid_places_guid(root.getChild(0).pageGuid);
+  Assert.equal(root.getChild(0).bookmarkGuid, "");
+  root.containerOpen = false;
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_addItemsWithInvalidGUIDsFails() {
+  const INVALID_GUID = "XYZ";
+  try {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      guid: INVALID_GUID,
+      title: "XYZ folder",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+    do_throw("Adding a folder with an invalid guid should fail");
+  } catch (ex) {}
+
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    title: "test folder",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  try {
+    PlacesUtils.bookmarks.insert({
+      parentGuid: folder.guid,
+      guid: INVALID_GUID,
+      title: "title",
+      url: "http://test.tld",
+    });
+    do_throw("Adding a bookmark with an invalid guid should fail");
+  } catch (ex) {}
+
+  try {
+    PlacesUtils.bookmarks.insert({
+      parentGuid: folder.guid,
+      guid: INVALID_GUID,
+      type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+    });
+    do_throw("Adding a separator with an invalid guid should fail");
+  } catch (ex) {}
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_addItemsWithGUIDs() {
+  const FOLDER_GUID = "FOLDER--GUID";
+  const BOOKMARK_GUID = "BM------GUID";
+  const SEPARATOR_GUID = "SEP-----GUID";
+
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "test folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        guid: FOLDER_GUID,
+        children: [
+          {
+            url: "http://test1.com",
+            title: "1 title",
+            guid: BOOKMARK_GUID,
+          },
+          {
+            type: PlacesUtils.bookmarks.TYPE_SEPARATOR,
+            guid: SEPARATOR_GUID,
+          },
+        ],
+      },
+    ],
+  });
+
+  let root = PlacesUtils.getFolderContents(bookmarks[0].guid).root;
+  Assert.equal(root.childCount, 2);
+  Assert.equal(root.bookmarkGuid, FOLDER_GUID);
+  Assert.equal(root.getChild(0).bookmarkGuid, BOOKMARK_GUID);
+  Assert.equal(root.getChild(1).bookmarkGuid, SEPARATOR_GUID);
+
+  root.containerOpen = false;
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_emptyGUIDFails() {
+  try {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      guid: "",
+      title: "test folder",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+    do_throw("Adding a folder with an empty guid should fail");
+  } catch (ex) {}
+});
+
+add_task(async function test_usingSameGUIDFails() {
+  const GUID = "XYZXYZXYZXYZ";
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    guid: GUID,
+    title: "test folder",
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+  });
+  try {
+    await PlacesUtils.bookmarks.insert({
+      parentGuid: PlacesUtils.bookmarks.menuGuid,
+      guid: GUID,
+      title: "test folder 2",
+      type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    });
+    do_throw("Using the same guid twice should fail");
+  } catch (ex) {}
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/unit/test_placeURIs.js b/toolkit/components/places/tests/unit/test_placeURIs.js
new file mode 100644
index 0000000000..093dc89f68
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_placeURIs.js
@@ -0,0 +1,18 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  // TODO: Improve testing coverage for QueryToQueryString and QueryStringToQuery
+
+  // Bug 376798
+  let query = PlacesUtils.history.getNewQuery();
+  let options = PlacesUtils.history.getNewQueryOptions();
+  query.setParents([PlacesUtils.bookmarks.rootGuid]);
+  Assert.equal(
+    PlacesUtils.history.queryToQueryString(query, options),
+    `place:parent=${PlacesUtils.bookmarks.rootGuid}`
+  );
+}
diff --git a/toolkit/components/places/tests/unit/test_promiseBookmarksTree.js b/toolkit/components/places/tests/unit/test_promiseBookmarksTree.js
new file mode 100644
index 0000000000..e42bf3b2d8
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_promiseBookmarksTree.js
@@ -0,0 +1,282 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+async function check_has_child(aParentGuid, aChildGuid) {
+  let parentTree = await PlacesUtils.promiseBookmarksTree(aParentGuid);
+  Assert.ok("children" in parentTree);
+  Assert.notEqual(
+    parentTree.children.find(e => e.guid == aChildGuid),
+    null
+  );
+}
+
+async function compareToNode(aItem, aNode, aIsRootItem, aExcludedGuids = []) {
+  // itemId==-1 indicates a non-bookmark node, which is unexpected.
+  Assert.notEqual(aNode.itemId, -1);
+
+  function check_unset(...aProps) {
+    for (let p of aProps) {
+      if (p in aItem) {
+        Assert.ok(false, `Unexpected property ${p} with value ${aItem[p]}`);
+      }
+    }
+  }
+
+  function compare_prop(aItemProp, aNodeProp = aItemProp, aOptional = false) {
+    if (aOptional && aNode[aNodeProp] === null) {
+      check_unset(aItemProp);
+    } else {
+      Assert.strictEqual(aItem[aItemProp], aNode[aNodeProp]);
+    }
+  }
+
+  // Bug 1013053 - bookmarkIndex is unavailable for the query's root
+  if (aNode.bookmarkIndex == -1) {
+    let bookmark = await PlacesUtils.bookmarks.fetch(aNode.bookmarkGuid);
+    Assert.strictEqual(aItem.index, bookmark.index);
+  } else {
+    compare_prop("index", "bookmarkIndex");
+  }
+
+  compare_prop("dateAdded");
+  compare_prop("lastModified");
+
+  if (aIsRootItem && aNode.bookmarkGuid != PlacesUtils.bookmarks.rootGuid) {
+    Assert.ok("parentGuid" in aItem);
+    await check_has_child(aItem.parentGuid, aItem.guid);
+  } else {
+    check_unset("parentGuid");
+  }
+
+  const BOOKMARK_ONLY_PROPS = ["uri", "iconUri", "tags", "charset", "keyword"];
+  const FOLDER_ONLY_PROPS = ["children", "root"];
+
+  let nodesCount = 1;
+
+  switch (aNode.type) {
+    case Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER:
+      Assert.equal(aItem.type, PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER);
+      Assert.equal(aItem.typeCode, PlacesUtils.bookmarks.TYPE_FOLDER);
+      compare_prop("title", "title", true);
+      check_unset(...BOOKMARK_ONLY_PROPS);
+
+      let expectedChildrenNodes = [];
+
+      PlacesUtils.asContainer(aNode);
+      if (!aNode.containerOpen) {
+        aNode.containerOpen = true;
+      }
+
+      for (let i = 0; i < aNode.childCount; i++) {
+        let childNode = aNode.getChild(i);
+        if (
+          childNode.itemId == PlacesUtils.tagsFolderId ||
+          aExcludedGuids.includes(childNode.bookmarkGuid)
+        ) {
+          continue;
+        }
+        expectedChildrenNodes.push(childNode);
+      }
+
+      if (expectedChildrenNodes.length) {
+        Assert.ok(Array.isArray(aItem.children));
+        Assert.equal(aItem.children.length, expectedChildrenNodes.length);
+        for (let i = 0; i < aItem.children.length; i++) {
+          nodesCount += await compareToNode(
+            aItem.children[i],
+            expectedChildrenNodes[i],
+            false,
+            aExcludedGuids
+          );
+        }
+      } else {
+        check_unset("children");
+      }
+
+      let rootName = mapItemGuidToInternalRootName(aItem.guid);
+      if (rootName) {
+        Assert.equal(aItem.root, rootName);
+      } else {
+        check_unset("root");
+      }
+      break;
+    case Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR:
+      Assert.equal(aItem.type, PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR);
+      Assert.equal(aItem.typeCode, PlacesUtils.bookmarks.TYPE_SEPARATOR);
+      check_unset(...BOOKMARK_ONLY_PROPS, ...FOLDER_ONLY_PROPS);
+      break;
+    default:
+      Assert.equal(aItem.type, PlacesUtils.TYPE_X_MOZ_PLACE);
+      Assert.equal(aItem.typeCode, PlacesUtils.bookmarks.TYPE_BOOKMARK);
+      compare_prop("uri");
+      // node.tags's format is "a, b" whilst promiseBoookmarksTree is "a,b"
+      if (aNode.tags === null) {
+        check_unset("tags");
+      } else {
+        Assert.equal(aItem.tags, aNode.tags.replace(/, /g, ","));
+      }
+
+      if (aNode.icon) {
+        try {
+          await compareFavicons(aNode.icon, aItem.iconUri);
+        } catch (ex) {
+          info(ex);
+          todo_check_true(false);
+        }
+      } else {
+        check_unset(aItem.iconUri);
+      }
+
+      check_unset(...FOLDER_ONLY_PROPS);
+
+      let pageInfo = await PlacesUtils.history.fetch(aNode.uri, {
+        includeAnnotations: true,
+      });
+      let expectedCharset = pageInfo.annotations.get(PlacesUtils.CHARSET_ANNO);
+      if (expectedCharset) {
+        Assert.equal(aItem.charset, expectedCharset);
+      } else {
+        check_unset("charset");
+      }
+
+      let entry = await PlacesUtils.keywords.fetch({ url: aNode.uri });
+      if (entry) {
+        Assert.equal(aItem.keyword, entry.keyword);
+      } else {
+        check_unset("keyword");
+      }
+
+      if ("title" in aItem) {
+        compare_prop("title");
+      } else {
+        Assert.equal(null, aNode.title);
+      }
+  }
+
+  if (aIsRootItem) {
+    Assert.strictEqual(aItem.itemsCount, nodesCount);
+  }
+
+  return nodesCount;
+}
+
+var itemsCount = 0;
+async function new_bookmark(aInfo) {
+  ++itemsCount;
+  if (!("url" in aInfo)) {
+    aInfo.url = uri("http://test.item.y" + itemsCount);
+  }
+
+  if (!("title" in aInfo)) {
+    aInfo.title = "Test Item (bookmark) " + itemsCount;
+  }
+
+  await PlacesTransactions.NewBookmark(aInfo).transact();
+}
+
+function new_folder(aInfo) {
+  if (!("title" in aInfo)) {
+    aInfo.title = "Test Item (folder) " + itemsCount;
+  }
+  return PlacesTransactions.NewFolder(aInfo).transact();
+}
+
+// Walks a result nodes tree and test promiseBookmarksTree for each node.
+// DO NOT COPY THIS LOGIC:  It is done here to accomplish a more comprehensive
+// test of the API (the entire hierarchy data is available in the very test).
+async function test_promiseBookmarksTreeForEachNode(
+  aNode,
+  aOptions,
+  aExcludedGuids
+) {
+  Assert.ok(aNode.bookmarkGuid && !!aNode.bookmarkGuid.length);
+  let item = await PlacesUtils.promiseBookmarksTree(
+    aNode.bookmarkGuid,
+    aOptions
+  );
+  await compareToNode(item, aNode, true, aExcludedGuids);
+
+  if (!PlacesUtils.nodeIsContainer(aNode)) {
+    return item;
+  }
+
+  for (let i = 0; i < aNode.childCount; i++) {
+    let child = aNode.getChild(i);
+    if (child.itemId != PlacesUtils.tagsFolderId) {
+      await test_promiseBookmarksTreeForEachNode(
+        child,
+        { includeItemIds: true },
+        aExcludedGuids
+      );
+    }
+  }
+  return item;
+}
+
+async function test_promiseBookmarksTreeAgainstResult(
+  aItemGuid = PlacesUtils.bookmarks.rootGuid,
+  aOptions = { includeItemIds: true },
+  aExcludedGuids
+) {
+  let node = PlacesUtils.getFolderContents(aItemGuid).root;
+  return test_promiseBookmarksTreeForEachNode(node, aOptions, aExcludedGuids);
+}
+
+add_task(async function () {
+  // Add some bookmarks to cover various use cases.
+  await new_bookmark({ parentGuid: PlacesUtils.bookmarks.toolbarGuid });
+  await new_folder({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    annotations: [
+      { name: "TestAnnoA", value: "TestVal" },
+      { name: "TestAnnoB", value: 0 },
+    ],
+  });
+  let sepInfo = { parentGuid: PlacesUtils.bookmarks.menuGuid };
+  await PlacesTransactions.NewSeparator(sepInfo).transact();
+  let folderGuid = await new_folder({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+  });
+  await new_bookmark({
+    title: null,
+    parentGuid: folderGuid,
+    keyword: "test_keyword",
+    tags: ["TestTagA", "TestTagB"],
+    annotations: [{ name: "TestAnnoA", value: "TestVal2" }],
+  });
+  let urlWithCharsetAndFavicon = uri("http://charset.and.favicon");
+  await new_bookmark({ parentGuid: folderGuid, url: urlWithCharsetAndFavicon });
+  await PlacesUtils.history.update({
+    url: urlWithCharsetAndFavicon,
+    annotations: new Map([[PlacesUtils.CHARSET_ANNO, "UTF-16"]]),
+  });
+  await setFaviconForPage(urlWithCharsetAndFavicon, SMALLPNG_DATA_URI);
+  // Test the default places root without specifying it.
+  await test_promiseBookmarksTreeAgainstResult();
+
+  // Do specify it
+  await test_promiseBookmarksTreeAgainstResult(PlacesUtils.bookmarks.rootGuid);
+
+  // Exclude the bookmarks menu.
+  // The calllback should be four times - once for the toolbar, once for
+  // the bookmark we inserted under, and once for the menu (and not
+  // at all for any of its descendants) and once for the unsorted bookmarks
+  // folder.  However, promiseBookmarksTree is called multiple times, so
+  // rather than counting the calls, we count the number of unique items
+  // passed in.
+  let guidsPassedToExcludeCallback = new Set();
+  let placesRootWithoutTheMenu = await test_promiseBookmarksTreeAgainstResult(
+    PlacesUtils.bookmarks.rootGuid,
+    {
+      excludeItemsCallback: aItem => {
+        guidsPassedToExcludeCallback.add(aItem.guid);
+        return aItem.root == "bookmarksMenuFolder";
+      },
+      includeItemIds: true,
+    },
+    [PlacesUtils.bookmarks.menuGuid]
+  );
+  Assert.equal(guidsPassedToExcludeCallback.size, 5);
+  Assert.equal(placesRootWithoutTheMenu.children.length, 3);
+});
diff --git a/toolkit/components/places/tests/unit/test_resolveNullBookmarkTitles.js b/toolkit/components/places/tests/unit/test_resolveNullBookmarkTitles.js
new file mode 100644
index 0000000000..d8830c5686
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_resolveNullBookmarkTitles.js
@@ -0,0 +1,39 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function () {
+  let uri1 = uri("http://foo.tld/");
+  let uri2 = uri("https://bar.tld/");
+
+  await PlacesTestUtils.addVisits([
+    { uri: uri1, title: "foo title" },
+    { uri: uri2, title: "bar title" },
+  ]);
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: uri1,
+    title: null,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: uri2,
+    title: null,
+  });
+
+  PlacesUtils.tagging.tagURI(uri1, ["tag 1"]);
+  PlacesUtils.tagging.tagURI(uri2, ["tag 2"]);
+});
+
+add_task(async function testTagQuery() {
+  let options = PlacesUtils.history.getNewQueryOptions();
+  let query = PlacesUtils.history.getNewQuery();
+  query.tags = ["tag 1"];
+  let root = PlacesUtils.history.executeQuery(query, options).root;
+  root.containerOpen = true;
+  Assert.equal(root.childCount, 1);
+  Assert.equal(root.getChild(0).title, "");
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_result_sort.js b/toolkit/components/places/tests/unit/test_result_sort.js
new file mode 100644
index 0000000000..840b40c339
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_result_sort.js
@@ -0,0 +1,112 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const NHQO = Ci.nsINavHistoryQueryOptions;
+
+add_task(async function test() {
+  const uri1 = "http://foo.tld/a";
+  const uri2 = "http://foo.tld/b";
+
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "Result-sort functionality tests root",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "b",
+            url: uri1,
+          },
+          {
+            title: "a",
+            url: uri2,
+          },
+          {
+            // url of the first child, title of second
+            title: "a",
+            url: uri1,
+          },
+        ],
+      },
+    ],
+  });
+
+  let guid1 = bookmarks[1].guid;
+  let guid2 = bookmarks[2].guid;
+  let guid3 = bookmarks[3].guid;
+
+  // query with natural order
+  let result = PlacesUtils.getFolderContents(bookmarks[0].guid);
+  let root = result.root;
+
+  Assert.equal(root.childCount, 3);
+
+  function checkOrder(a, b, c) {
+    Assert.equal(root.getChild(0).bookmarkGuid, a);
+    Assert.equal(root.getChild(1).bookmarkGuid, b);
+    Assert.equal(root.getChild(2).bookmarkGuid, c);
+  }
+
+  // natural order
+  info("Natural order");
+  checkOrder(guid1, guid2, guid3);
+
+  // title: guid3 should precede guid2 since we fall-back to URI-based sorting
+  info("Sort by title asc");
+  result.sortingMode = NHQO.SORT_BY_TITLE_ASCENDING;
+  checkOrder(guid3, guid2, guid1);
+
+  // In reverse
+  info("Sort by title desc");
+  result.sortingMode = NHQO.SORT_BY_TITLE_DESCENDING;
+  checkOrder(guid1, guid2, guid3);
+
+  // uri sort: guid1 should precede guid3 since we fall-back to natural order
+  info("Sort by uri asc");
+  result.sortingMode = NHQO.SORT_BY_URI_ASCENDING;
+  checkOrder(guid1, guid3, guid2);
+
+  // test live update
+  info("Change bookmark uri liveupdate");
+  await PlacesUtils.bookmarks.update({
+    guid: guid1,
+    url: uri2,
+  });
+  checkOrder(guid3, guid1, guid2);
+  await PlacesUtils.bookmarks.update({
+    guid: guid1,
+    url: uri1,
+  });
+  checkOrder(guid1, guid3, guid2);
+
+  // XXXtodo: test history sortings (visit count, visit date)
+  // XXXtodo: test different item types once folderId and bookmarkId are merged.
+
+  // XXXtodo:  test dateAdded sort
+  // XXXtodo:  test lastModified sort
+
+  // Add a visit, then check frecency ordering.
+
+  await PlacesTestUtils.addVisits({ uri: uri2, transition: TRANSITION_TYPED });
+
+  info("Sort by frecency desc");
+  result.sortingMode = NHQO.SORT_BY_FRECENCY_DESCENDING;
+  for (let i = 0; i < root.childCount; ++i) {
+    print(root.getChild(i).uri + " " + root.getChild(i).title);
+  }
+  // For guid1 and guid3, since they have same frecency and no visits, fallback
+  // to sort by the newest bookmark.
+  checkOrder(guid2, guid3, guid1);
+  info("Sort by frecency asc");
+  result.sortingMode = NHQO.SORT_BY_FRECENCY_ASCENDING;
+  for (let i = 0; i < root.childCount; ++i) {
+    print(root.getChild(i).uri + " " + root.getChild(i).title);
+  }
+  checkOrder(guid1, guid3, guid2);
+
+  root.containerOpen = false;
+});
diff --git a/toolkit/components/places/tests/unit/test_resultsAsVisit_details.js b/toolkit/components/places/tests/unit/test_resultsAsVisit_details.js
new file mode 100644
index 0000000000..29963ad269
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_resultsAsVisit_details.js
@@ -0,0 +1,100 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+const { history } = PlacesUtils;
+
+add_task(async function test_addVisitCheckFields() {
+  let uri = NetUtil.newURI("http://test4.com/");
+  await PlacesTestUtils.addVisits([
+    { uri },
+    { uri, referrer: uri },
+    { uri, transition: history.TRANSITION_TYPED },
+  ]);
+
+  let options = history.getNewQueryOptions();
+  let query = history.getNewQuery();
+
+  query.uri = uri;
+
+  // Check RESULTS_AS_VISIT node.
+  options.resultType = options.RESULTS_AS_VISIT;
+
+  let root = history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  equal(root.childCount, 3);
+
+  let child = root.getChild(0);
+  equal(
+    child.visitType,
+    history.TRANSITION_LINK,
+    "Visit type should be TRANSITION_LINK"
+  );
+  equal(child.visitId, 1, "Visit ID should be 1");
+
+  child = root.getChild(1);
+  equal(
+    child.visitType,
+    history.TRANSITION_LINK,
+    "Visit type should be TRANSITION_LINK"
+  );
+  equal(child.visitId, 2, "Visit ID should be 2");
+
+  child = root.getChild(2);
+  equal(
+    child.visitType,
+    history.TRANSITION_TYPED,
+    "Visit type should be TRANSITION_TYPED"
+  );
+  equal(child.visitId, 3, "Visit ID should be 3");
+
+  root.containerOpen = false;
+
+  // Check RESULTS_AS_URI node.
+  options.resultType = options.RESULTS_AS_URI;
+
+  root = history.executeQuery(query, options).root;
+  root.containerOpen = true;
+
+  equal(root.childCount, 1);
+
+  child = root.getChild(0);
+  equal(child.visitType, 0, "Visit type should be 0");
+  equal(child.visitId, -1, "Visit ID should be -1");
+
+  root.containerOpen = false;
+
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function test_bookmarkFields() {
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "test folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "test title",
+            url: "http://test4.com",
+          },
+        ],
+      },
+    ],
+  });
+
+  let root = PlacesUtils.getFolderContents(bookmarks[0].guid).root;
+  equal(root.childCount, 1);
+
+  equal(root.visitType, 0, "Visit type should be 0");
+  equal(root.visitId, -1, "Visit ID should be -1");
+
+  let child = root.getChild(0);
+  equal(child.visitType, 0, "Visit type should be 0");
+  equal(child.visitId, -1, "Visit ID should be -1");
+
+  root.containerOpen = false;
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
diff --git a/toolkit/components/places/tests/unit/test_sql_function_origin.js b/toolkit/components/places/tests/unit/test_sql_function_origin.js
new file mode 100644
index 0000000000..0314ff5040
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_sql_function_origin.js
@@ -0,0 +1,79 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests the origin-related SQL functions, which are:
+// * get_host_and_port
+// * get_prefix
+// * strip_prefix_and_userinfo
+
+// Tests actual URL strings.
+add_task(async function urls() {
+  let sets = [
+    ["http:"],
+    ["", "//"],
+    ["", "user@", "user:@", "user:pass@", "user:pass:word@"],
+    ["example.com"],
+    ["", ":8888"],
+    ["", "/", "/foo"],
+    ["", "?", "?bar"],
+    ["", "#", "#baz"],
+  ];
+  let db = await PlacesUtils.promiseDBConnection();
+  for (let parts of permute(sets)) {
+    let spec = parts.join("");
+    let funcs = {
+      get_prefix: parts.slice(0, 2).join(""),
+      get_host_and_port: parts.slice(3, 5).join(""),
+      strip_prefix_and_userinfo: parts.slice(3).join(""),
+    };
+    for (let [func, expectedValue] of Object.entries(funcs)) {
+      let rows = await db.execute(`
+        SELECT ${func}("${spec}");
+      `);
+      let value = rows[0].getString(0);
+      Assert.equal(value, expectedValue, `function=${func} spec="${spec}"`);
+    }
+  }
+});
+
+// Tests strings that aren't URLs.
+add_task(async function nonURLs() {
+  let db = await PlacesUtils.promiseDBConnection();
+
+  let value = (
+    await db.execute(`
+    SELECT get_prefix("hello");
+  `)
+  )[0].getString(0);
+  Assert.equal(value, "");
+
+  value = (
+    await db.execute(`
+    SELECT get_host_and_port("hello");
+  `)
+  )[0].getString(0);
+  Assert.equal(value, "hello");
+
+  value = (
+    await db.execute(`
+    SELECT strip_prefix_and_userinfo("hello");
+  `)
+  )[0].getString(0);
+  Assert.equal(value, "hello");
+});
+
+function permute(sets = []) {
+  if (!sets.length) {
+    return [[]];
+  }
+  let firstSet = sets[0];
+  let otherSets = sets.slice(1);
+  let permutedSequences = [];
+  let otherPermutedSequences = permute(otherSets);
+  for (let other of otherPermutedSequences) {
+    for (let value of firstSet) {
+      permutedSequences.push([value].concat(other));
+    }
+  }
+  return permutedSequences;
+}
diff --git a/toolkit/components/places/tests/unit/test_sql_guid_functions.js b/toolkit/components/places/tests/unit/test_sql_guid_functions.js
new file mode 100644
index 0000000000..b4fbdac612
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_sql_guid_functions.js
@@ -0,0 +1,94 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests that the guid function generates a guid of the proper length,
+ * with no invalid characters.
+ */
+
+/**
+ * Checks all our invariants about our guids for a given result.
+ *
+ * @param aGuid
+ *        The guid to check.
+ */
+function check_invariants(aGuid) {
+  info("Checking guid '" + aGuid + "'");
+
+  do_check_valid_places_guid(aGuid);
+}
+
+// Test Functions
+
+function test_guid_invariants() {
+  const kExpectedChars = 64;
+  const kAllowedChars =
+    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_";
+  Assert.equal(kAllowedChars.length, kExpectedChars);
+  const kGuidLength = 12;
+
+  let checkedChars = [];
+  for (let i = 0; i < kGuidLength; i++) {
+    checkedChars[i] = {};
+    for (let j = 0; j < kAllowedChars; j++) {
+      checkedChars[i][kAllowedChars[j]] = false;
+    }
+  }
+
+  // We run this until we've seen every character that we expect to see in every
+  // position.
+  let seenChars = 0;
+  let stmt = DBConn().createStatement("SELECT GENERATE_GUID()");
+  while (seenChars != kExpectedChars * kGuidLength) {
+    Assert.ok(stmt.executeStep());
+    let guid = stmt.getString(0);
+    check_invariants(guid);
+
+    for (let i = 0; i < guid.length; i++) {
+      let character = guid[i];
+      if (!checkedChars[i][character]) {
+        checkedChars[i][character] = true;
+        seenChars++;
+      }
+    }
+    stmt.reset();
+  }
+  stmt.finalize();
+
+  // One last reality check - make sure all of our characters were seen.
+  for (let i = 0; i < kGuidLength; i++) {
+    for (let j = 0; j < kAllowedChars; j++) {
+      Assert.ok(checkedChars[i][kAllowedChars[j]]);
+    }
+  }
+
+  run_next_test();
+}
+
+function test_guid_on_background() {
+  // We should not assert if we execute this asynchronously.
+  let stmt = DBConn().createAsyncStatement("SELECT GENERATE_GUID()");
+  let checked = false;
+  stmt.executeAsync({
+    handleResult(aResult) {
+      try {
+        let row = aResult.getNextRow();
+        check_invariants(row.getResultByIndex(0));
+        Assert.equal(aResult.getNextRow(), null);
+        checked = true;
+      } catch (e) {
+        do_throw(e);
+      }
+    },
+    handleCompletion(aReason) {
+      Assert.equal(aReason, Ci.mozIStorageStatementCallback.REASON_FINISHED);
+      Assert.ok(checked);
+      run_next_test();
+    },
+  });
+  stmt.finalize();
+}
+
+// Test Runner
+
+[test_guid_invariants, test_guid_on_background].forEach(fn => add_test(fn));
diff --git a/toolkit/components/places/tests/unit/test_tag_autocomplete_search.js b/toolkit/components/places/tests/unit/test_tag_autocomplete_search.js
new file mode 100644
index 0000000000..43f899c237
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_tag_autocomplete_search.js
@@ -0,0 +1,119 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function AutoCompleteInput(aSearches) {
+  this.searches = aSearches;
+}
+AutoCompleteInput.prototype = {
+  constructor: AutoCompleteInput,
+
+  searches: null,
+
+  minResultsForPopup: 0,
+  timeout: 10,
+  searchParam: "",
+  textValue: "",
+  disableAutoComplete: false,
+  completeDefaultIndex: false,
+
+  get searchCount() {
+    return this.searches.length;
+  },
+
+  getSearchAt(aIndex) {
+    return this.searches[aIndex];
+  },
+
+  onSearchBegin() {},
+  onSearchComplete() {},
+
+  popupOpen: false,
+
+  popup: {
+    setSelectedIndex(aIndex) {},
+    invalidate() {},
+
+    // nsISupports implementation
+    QueryInterface: ChromeUtils.generateQI(["nsIAutoCompletePopup"]),
+  },
+
+  // nsISupports implementation
+  QueryInterface: ChromeUtils.generateQI(["nsIAutoCompleteInput"]),
+};
+
+async function ensure_tag_results(results, searchTerm) {
+  var controller = Cc["@mozilla.org/autocomplete/controller;1"].getService(
+    Ci.nsIAutoCompleteController
+  );
+
+  // Make an AutoCompleteInput that uses our searches
+  // and confirms results on search complete
+  var input = new AutoCompleteInput(["places-tag-autocomplete"]);
+
+  controller.input = input;
+
+  return new Promise(resolve => {
+    var numSearchesStarted = 0;
+    input.onSearchBegin = function input_onSearchBegin() {
+      numSearchesStarted++;
+      Assert.equal(numSearchesStarted, 1);
+    };
+
+    input.onSearchComplete = function input_onSearchComplete() {
+      Assert.equal(numSearchesStarted, 1);
+      if (results.length) {
+        Assert.equal(
+          controller.searchStatus,
+          Ci.nsIAutoCompleteController.STATUS_COMPLETE_MATCH
+        );
+      } else {
+        Assert.equal(
+          controller.searchStatus,
+          Ci.nsIAutoCompleteController.STATUS_COMPLETE_NO_MATCH
+        );
+      }
+
+      Assert.equal(controller.matchCount, results.length);
+      for (var i = 0; i < controller.matchCount; i++) {
+        Assert.equal(controller.getValueAt(i), results[i]);
+      }
+
+      resolve();
+    };
+
+    controller.startSearch(searchTerm);
+  });
+}
+
+var uri1 = uri("http://site.tld/1");
+
+var tests = [
+  () => ensure_tag_results(["bar", "Baz", "boo"], "b"),
+  () => ensure_tag_results(["bar", "Baz"], "ba"),
+  () => ensure_tag_results(["bar", "Baz"], "Ba"),
+  () => ensure_tag_results(["bar"], "bar"),
+  () => ensure_tag_results(["Baz"], "Baz"),
+  () => ensure_tag_results([], "barb"),
+  () => ensure_tag_results([], "foo"),
+  () =>
+    ensure_tag_results(["first tag, bar", "first tag, Baz"], "first tag, ba"),
+  () =>
+    ensure_tag_results(
+      ["first tag;  bar", "first tag;  Baz"],
+      "first tag;  ba"
+    ),
+];
+
+/**
+ * Test tag autocomplete
+ */
+add_task(async function test_tag_autocomplete() {
+  PlacesUtils.tagging.tagURI(uri1, ["bar", "Baz", "boo", "*nix"]);
+
+  for (let tagTest of tests) {
+    await tagTest();
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_tagging.js b/toolkit/components/places/tests/unit/test_tagging.js
new file mode 100644
index 0000000000..f38db0d0f6
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_tagging.js
@@ -0,0 +1,188 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Notice we use createInstance because later we will have to terminate the
+// service and restart it.
+var tagssvc = Cc["@mozilla.org/browser/tagging-service;1"]
+  .createInstance()
+  .QueryInterface(Ci.nsITaggingService);
+
+function run_test() {
+  var options = PlacesUtils.history.getNewQueryOptions();
+  var query = PlacesUtils.history.getNewQuery();
+
+  query.setParents([PlacesUtils.bookmarks.tagsGuid]);
+  var result = PlacesUtils.history.executeQuery(query, options);
+  var tagRoot = result.root;
+  tagRoot.containerOpen = true;
+
+  Assert.equal(tagRoot.childCount, 0);
+
+  var uri1 = uri("http://foo.tld/");
+  var uri2 = uri("https://bar.tld/");
+
+  // this also tests that the multiple folders are not created for the same tag
+  tagssvc.tagURI(uri1, ["tag 1"]);
+  tagssvc.tagURI(uri2, ["tag 1"]);
+  Assert.equal(tagRoot.childCount, 1);
+
+  var tag1node = tagRoot
+    .getChild(0)
+    .QueryInterface(Ci.nsINavHistoryContainerResultNode);
+  var tag1itemId = tag1node.itemId;
+
+  Assert.equal(tag1node.title, "tag 1");
+  tag1node.containerOpen = true;
+  Assert.equal(tag1node.childCount, 2);
+
+  // Tagging the same url twice (or even thrice!) with the same tag should be a
+  // no-op
+  tagssvc.tagURI(uri1, ["tag 1"]);
+  Assert.equal(tag1node.childCount, 2);
+  tagssvc.tagURI(uri1, [tag1itemId]);
+  Assert.equal(tag1node.childCount, 2);
+  Assert.equal(tagRoot.childCount, 1);
+
+  // also tests bug 407575
+  tagssvc.tagURI(uri1, [tag1itemId, "tag 1", "tag 2", "Tag 1", "Tag 2"]);
+  Assert.equal(tagRoot.childCount, 2);
+  Assert.equal(tag1node.childCount, 2);
+
+  // test getTagsForURI
+  var uri1tags = tagssvc.getTagsForURI(uri1);
+  Assert.equal(uri1tags.length, 2);
+  Assert.equal(uri1tags[0], "Tag 1");
+  Assert.equal(uri1tags[1], "Tag 2");
+  var uri2tags = tagssvc.getTagsForURI(uri2);
+  Assert.equal(uri2tags.length, 1);
+  Assert.equal(uri2tags[0], "Tag 1");
+
+  // test untagging
+  tagssvc.untagURI(uri1, ["tag 1"]);
+  Assert.equal(tag1node.childCount, 1);
+
+  let wait = PlacesTestUtils.waitForNotification("bookmark-removed", events =>
+    events.some(event => event.id == tagRoot.itemId)
+  );
+  // removing the last uri from a tag should remove the tag-container
+  tagssvc.untagURI(uri2, ["tag 1"]);
+  wait.then(() => {
+    Assert.equal(tagRoot.childCount, 1);
+  });
+
+  // cleanup
+  tag1node.containerOpen = false;
+
+  // get array of tag folder ids => title
+  // for testing tagging with mixed folder ids and tags
+  var child = tagRoot.getChild(0);
+  var tagId = child.itemId;
+  var tagTitle = child.title;
+
+  // test mixed id/name tagging
+  // as well as non-id numeric tags
+  var uri3 = uri("http://testuri/3");
+  tagssvc.tagURI(uri3, [tagId, "tag 3", "456"]);
+  var tags = tagssvc.getTagsForURI(uri3);
+  Assert.ok(tags.includes(tagTitle));
+  Assert.ok(tags.includes("tag 3"));
+  Assert.ok(tags.includes("456"));
+
+  // test mixed id/name tagging
+  tagssvc.untagURI(uri3, [tagId, "tag 3", "456"]);
+  tags = tagssvc.getTagsForURI(uri3);
+  Assert.equal(tags.length, 0);
+
+  // Terminate tagging service, fire up a new instance and check that existing
+  // tags are there.  This will ensure that any internal caching system is
+  // correctly filled at startup and we are not losing previously existing tags.
+  var uri4 = uri("http://testuri/4");
+  tagssvc.tagURI(uri4, [tagId, "tag 3", "456"]);
+  tagssvc = null;
+  tagssvc = Cc["@mozilla.org/browser/tagging-service;1"].getService(
+    Ci.nsITaggingService
+  );
+  var uri4Tags = tagssvc.getTagsForURI(uri4);
+  Assert.equal(uri4Tags.length, 3);
+  Assert.ok(uri4Tags.includes(tagTitle));
+  Assert.ok(uri4Tags.includes("tag 3"));
+  Assert.ok(uri4Tags.includes("456"));
+
+  // Test sparse arrays.
+  let curChildCount = tagRoot.childCount;
+
+  try {
+    tagssvc.tagURI(uri1, [undefined, "tagSparse"]);
+    Assert.equal(tagRoot.childCount, curChildCount + 1);
+  } catch (ex) {
+    do_throw("Passing a sparse array should not throw");
+  }
+  try {
+    wait = PlacesTestUtils.waitForNotification("bookmark-removed", events =>
+      events.some(event => event.id == tagRoot.itemId)
+    );
+    tagssvc.untagURI(uri1, [undefined, "tagSparse"]);
+    wait.then(() => {
+      Assert.equal(tagRoot.childCount, curChildCount);
+    });
+  } catch (ex) {
+    do_throw("Passing a sparse array should not throw");
+  }
+
+  // Test that the API throws for bad arguments.
+  try {
+    tagssvc.tagURI(uri1, ["", "test"]);
+    do_throw("Passing a bad tags array should throw");
+  } catch (ex) {
+    Assert.equal(ex.name, "NS_ERROR_ILLEGAL_VALUE");
+  }
+  try {
+    tagssvc.untagURI(uri1, ["", "test"]);
+    do_throw("Passing a bad tags array should throw");
+  } catch (ex) {
+    Assert.equal(ex.name, "NS_ERROR_ILLEGAL_VALUE");
+  }
+  try {
+    tagssvc.tagURI(uri1, [0, "test"]);
+    do_throw("Passing a bad tags array should throw");
+  } catch (ex) {
+    Assert.equal(ex.name, "NS_ERROR_ILLEGAL_VALUE");
+  }
+  try {
+    tagssvc.tagURI(uri1, [0, "test"]);
+    do_throw("Passing a bad tags array should throw");
+  } catch (ex) {
+    Assert.equal(ex.name, "NS_ERROR_ILLEGAL_VALUE");
+  }
+
+  // Tag name length should be limited to PlacesUtils.bookmarks.MAX_TAG_LENGTH (bug407821)
+  try {
+    // generate a long tag name. i.e. looooo...oong_tag
+    var n = PlacesUtils.bookmarks.MAX_TAG_LENGTH;
+    var someOos = new Array(n).join("o");
+    var longTagName = "l" + someOos + "ng_tag";
+
+    tagssvc.tagURI(uri1, ["short_tag", longTagName]);
+    do_throw("Passing a bad tags array should throw");
+  } catch (ex) {
+    Assert.equal(ex.name, "NS_ERROR_ILLEGAL_VALUE");
+  }
+
+  // cleanup
+  tagRoot.containerOpen = false;
+
+  // Tagging service should trim tags (Bug967196)
+  let exampleURI = uri("http://www.example.com/");
+  PlacesUtils.tagging.tagURI(exampleURI, [" test "]);
+
+  let exampleTags = PlacesUtils.tagging.getTagsForURI(exampleURI);
+  Assert.equal(exampleTags.length, 1);
+  Assert.equal(exampleTags[0], "test");
+
+  PlacesUtils.tagging.untagURI(exampleURI, ["test"]);
+  exampleTags = PlacesUtils.tagging.getTagsForURI(exampleURI);
+  Assert.equal(exampleTags.length, 0);
+}
diff --git a/toolkit/components/places/tests/unit/test_telemetry.js b/toolkit/components/places/tests/unit/test_telemetry.js
new file mode 100644
index 0000000000..b48bb76a7f
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_telemetry.js
@@ -0,0 +1,151 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests common Places telemetry probes by faking the telemetry service.
+
+// Enable the collection (during test) for all products so even products
+// that don't collect the data will be able to run the test without failure.
+Services.prefs.setBoolPref(
+  "toolkit.telemetry.testing.overrideProductsCheck",
+  true
+);
+
+const { PlacesDBUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PlacesDBUtils.sys.mjs"
+);
+
+const histograms = {
+  PLACES_PAGES_COUNT: val => Assert.equal(val, 1),
+  PLACES_BOOKMARKS_COUNT: val => Assert.equal(val, 1),
+  PLACES_TAGS_COUNT: val => Assert.equal(val, 1),
+  PLACES_KEYWORDS_COUNT: val => Assert.equal(val, 1),
+  PLACES_SORTED_BOOKMARKS_PERC: val => Assert.equal(val, 100),
+  PLACES_TAGGED_BOOKMARKS_PERC: val => Assert.equal(val, 100),
+  PLACES_DATABASE_FILESIZE_MB: val => Assert.ok(val > 0),
+  PLACES_DATABASE_FAVICONS_FILESIZE_MB: val => Assert.ok(val > 0),
+  PLACES_EXPIRATION_STEPS_TO_CLEAN2: val => Assert.ok(val > 1),
+  PLACES_IDLE_MAINTENANCE_TIME_MS: val => Assert.ok(val > 0),
+  PLACES_ANNOS_PAGES_COUNT: val => Assert.equal(val, 1),
+  PLACES_MAINTENANCE_DAYSFROMLAST: val => Assert.ok(val >= 0),
+};
+
+const scalars = {
+  pages_need_frecency_recalculation: 1, // 1 bookmark is added causing recalc.
+};
+
+/**
+ * Forces an expiration run.
+ *
+ * @param [optional] aLimit
+ *        Limit for the expiration.  Pass -1 for unlimited.
+ *        Any other non-positive value will just expire orphans.
+ *
+ * @return {Promise}
+ * @resolves When expiration finishes.
+ * @rejects Never.
+ */
+function promiseForceExpirationStep(aLimit) {
+  let promise = promiseTopicObserved(PlacesUtils.TOPIC_EXPIRATION_FINISHED);
+  let expire = Cc["@mozilla.org/places/expiration;1"].getService(
+    Ci.nsIObserver
+  );
+  expire.observe(null, "places-debug-start-expiration", aLimit);
+  return promise;
+}
+
+/**
+ * Returns a PRTime in the past usable to add expirable visits.
+ *
+ * param [optional] daysAgo
+ *       Expiration ignores any visit added in the last 7 days, so by default
+ *       this will be set to 7.
+ * @note to be safe against DST issues we go back one day more.
+ */
+function getExpirablePRTime(daysAgo = 7) {
+  let dateObj = new Date();
+  // Normalize to midnight
+  dateObj.setHours(0);
+  dateObj.setMinutes(0);
+  dateObj.setSeconds(0);
+  dateObj.setMilliseconds(0);
+  dateObj = new Date(dateObj.getTime() - (daysAgo + 1) * 86400000);
+  return dateObj.getTime() * 1000;
+}
+
+add_task(async function test_execute() {
+  // Put some trash in the database.
+  let uri = Services.io.newURI("http://moz.org/");
+
+  PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.unfiledGuid,
+    children: [
+      {
+        title: "moz test",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            title: "moz test",
+            url: uri,
+          },
+        ],
+      },
+    ],
+  });
+
+  PlacesUtils.tagging.tagURI(uri, ["tag"]);
+  await PlacesUtils.keywords.insert({ url: uri.spec, keyword: "keyword" });
+
+  // Set a large annotation.
+  let content = "";
+  while (content.length < 1024) {
+    content += "0";
+  }
+
+  await PlacesUtils.history.update({
+    url: uri,
+    annotations: new Map([["test-anno", content]]),
+  });
+
+  await PlacesDBUtils.telemetry();
+
+  await PlacesTestUtils.promiseAsyncUpdates();
+
+  // Test expiration probes.
+  let timeInMicroseconds = getExpirablePRTime(8);
+
+  function newTimeInMicroseconds() {
+    timeInMicroseconds = timeInMicroseconds + 1000;
+    return timeInMicroseconds;
+  }
+
+  for (let i = 0; i < 3; i++) {
+    await PlacesTestUtils.addVisits({
+      uri: NetUtil.newURI("http://" + i + ".moz.org/"),
+      visitDate: newTimeInMicroseconds(),
+    });
+  }
+  Services.prefs.setIntPref("places.history.expiration.max_pages", 0);
+  await promiseForceExpirationStep(2);
+  await promiseForceExpirationStep(2);
+
+  // Test idle probes.
+  await PlacesDBUtils.maintenanceOnIdle();
+
+  for (let histogramId in histograms) {
+    info("checking histogram " + histogramId);
+    let validate = histograms[histogramId];
+    let snapshot = Services.telemetry.getHistogramById(histogramId).snapshot();
+    validate(snapshot.sum);
+    Assert.ok(Object.values(snapshot.values).reduce((a, b) => a + b, 0) > 0);
+  }
+  for (let scalarName in scalars) {
+    let scalar = "places." + scalarName;
+    info("checking scalar " + scalar);
+    TelemetryTestUtils.assertScalar(
+      TelemetryTestUtils.getProcessScalars("parent"),
+      scalar,
+      scalars[scalarName],
+      "Verify scalar value matches"
+    );
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_update_frecency_after_delete.js b/toolkit/components/places/tests/unit/test_update_frecency_after_delete.js
new file mode 100644
index 0000000000..fa03c0e06b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_update_frecency_after_delete.js
@@ -0,0 +1,211 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Bug 455315
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=412132
+ *
+ * Ensures that the frecency of a bookmark's URI is what it should be after the
+ * bookmark is deleted.
+ */
+
+add_task(async function removed_bookmark() {
+  info(
+    "After removing bookmark, frecency of bookmark's URI should be " +
+      "zero if URI is unvisited and no longer bookmarked."
+  );
+  const TEST_URI = Services.io.newURI("http://example.com/1");
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URI,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Bookmarked => frecency of URI should be != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.remove(bm);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Unvisited URI no longer bookmarked => frecency should = 0");
+  Assert.equal(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function removed_but_visited_bookmark() {
+  info(
+    "After removing bookmark, frecency of bookmark's URI should " +
+      "not be zero if URI is visited."
+  );
+  const TEST_URI = Services.io.newURI("http://example.com/1");
+  let bm = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URI,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Bookmarked => frecency of URI should be != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesTestUtils.addVisits(TEST_URI);
+  await PlacesUtils.bookmarks.remove(bm);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("*Visited* URI no longer bookmarked => frecency should != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function remove_bookmark_still_bookmarked() {
+  info(
+    "After removing bookmark, frecency of bookmark's URI should " +
+      "not be zero if URI is still bookmarked."
+  );
+  const TEST_URI = Services.io.newURI("http://example.com/1");
+  let bm1 = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark 1 title",
+    url: TEST_URI,
+  });
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark 2 title",
+    url: TEST_URI,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Bookmarked => frecency of URI should be != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.remove(bm1);
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("URI still bookmarked => frecency should != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function cleared_parent_of_visited_bookmark() {
+  info(
+    "After removing all children from bookmark's parent, frecency " +
+      "of bookmark's URI should not be zero if URI is visited."
+  );
+  const TEST_URI = Services.io.newURI("http://example.com/1");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    title: "bookmark title",
+    url: TEST_URI,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Bookmarked => frecency of URI should be != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesTestUtils.addVisits(TEST_URI);
+  await PlacesUtils.bookmarks.eraseEverything();
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("*Visited* URI no longer bookmarked => frecency should != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
+
+add_task(async function cleared_parent_of_bookmark_still_bookmarked() {
+  info(
+    "After removing all children from bookmark's parent, frecency " +
+      "of bookmark's URI should not be zero if URI is still " +
+      "bookmarked."
+  );
+  const TEST_URI = Services.io.newURI("http://example.com/1");
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "bookmark 1 title",
+    url: TEST_URI,
+  });
+
+  let folder = await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.unfiledGuid,
+    type: PlacesUtils.bookmarks.TYPE_FOLDER,
+    title: "bookmark 2 folder",
+  });
+  await PlacesUtils.bookmarks.insert({
+    title: "bookmark 2 title",
+    parentGuid: folder.guid,
+    url: TEST_URI,
+  });
+
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  info("Bookmarked => frecency of URI should be != 0");
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.remove(folder);
+  await PlacesFrecencyRecalculator.recalculateAnyOutdatedFrecencies();
+  // URI still bookmarked => frecency should != 0.
+  Assert.notEqual(
+    await PlacesTestUtils.getDatabaseValue("moz_places", "frecency", {
+      url: TEST_URI,
+    }),
+    0
+  );
+
+  await PlacesUtils.bookmarks.eraseEverything();
+  await PlacesUtils.history.clear();
+});
diff --git a/toolkit/components/places/tests/unit/test_utils_backups_create.js b/toolkit/components/places/tests/unit/test_utils_backups_create.js
new file mode 100644
index 0000000000..a0bc506695
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_utils_backups_create.js
@@ -0,0 +1,152 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Check for correct functionality of bookmarks backups
+ */
+
+const NUMBER_OF_BACKUPS = 10;
+
+async function createBackups(nBackups, dateObj, bookmarksBackupDir) {
+  // Generate random dates.
+  let dates = [];
+  while (dates.length < nBackups) {
+    // Use last year to ensure today's backup is the newest.
+    let randomDate = new Date(
+      dateObj.getFullYear() - 1,
+      Math.floor(12 * Math.random()),
+      Math.floor(28 * Math.random())
+    );
+    if (!dates.includes(randomDate.getTime())) {
+      dates.push(randomDate.getTime());
+    }
+  }
+  // Sort dates from oldest to newest.
+  dates.sort();
+
+  // Fake backups are created backwards to ensure we won't consider file
+  // creation time.
+  // Create fake backups for the newest dates.
+  for (let i = dates.length - 1; i >= 0; i--) {
+    let backupFilename = PlacesBackups.getFilenameForDate(new Date(dates[i]));
+    let backupFile = bookmarksBackupDir.clone();
+    backupFile.append(backupFilename);
+    backupFile.create(Ci.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
+    info("Creating fake backup " + backupFile.leafName);
+    if (!backupFile.exists()) {
+      do_throw("Unable to create fake backup " + backupFile.leafName);
+    }
+  }
+
+  return dates;
+}
+
+async function checkBackups(dates, bookmarksBackupDir) {
+  // Check backups.  We have 11 dates but we the max number is 10 so the
+  // oldest backup should have been removed.
+  for (let i = 0; i < dates.length; i++) {
+    let backupFilename;
+    let shouldExist;
+    let backupFile;
+    if (i > 0) {
+      let files = bookmarksBackupDir.directoryEntries;
+      while (files.hasMoreElements()) {
+        let entry = files.nextFile;
+        if (PlacesBackups.filenamesRegex.test(entry.leafName)) {
+          backupFilename = entry.leafName;
+          backupFile = entry;
+          break;
+        }
+      }
+      shouldExist = true;
+    } else {
+      backupFilename = PlacesBackups.getFilenameForDate(new Date(dates[i]));
+      backupFile = bookmarksBackupDir.clone();
+      backupFile.append(backupFilename);
+      shouldExist = false;
+    }
+    if (backupFile.exists() != shouldExist) {
+      do_throw(
+        "Backup should " +
+          (shouldExist ? "" : "not") +
+          " exist: " +
+          backupFilename
+      );
+    }
+  }
+}
+
+async function cleanupFiles(bookmarksBackupDir) {
+  // Cleanup backups folder.
+  // XXX: Can't use bookmarksBackupDir.remove(true) because file lock happens
+  // on WIN XP.
+  let files = bookmarksBackupDir.directoryEntries;
+  while (files.hasMoreElements()) {
+    let entry = files.nextFile;
+    entry.remove(false);
+  }
+  // Clear cache to match the manual removing of files
+  delete PlacesBackups._backupFiles;
+  Assert.ok(!bookmarksBackupDir.directoryEntries.hasMoreElements());
+}
+
+add_task(async function test_create_backups() {
+  let backupFolderPath = await PlacesBackups.getBackupFolder();
+  let bookmarksBackupDir = new FileUtils.File(backupFolderPath);
+
+  let dateObj = new Date();
+  let dates = await createBackups(
+    NUMBER_OF_BACKUPS,
+    dateObj,
+    bookmarksBackupDir
+  );
+  // Add today's backup.
+  await PlacesBackups.create(NUMBER_OF_BACKUPS);
+  dates.push(dateObj.getTime());
+  await checkBackups(dates, bookmarksBackupDir);
+  await cleanupFiles(bookmarksBackupDir);
+});
+
+add_task(async function test_saveBookmarks_with_no_backups() {
+  let backupFolderPath = await PlacesBackups.getBackupFolder();
+  let bookmarksBackupDir = new FileUtils.File(backupFolderPath);
+
+  Services.prefs.setIntPref("browser.bookmarks.max_backups", 0);
+
+  let filePath = PathUtils.join(do_get_tempdir().path, "backup.json");
+  await PlacesBackups.saveBookmarksToJSONFile(filePath);
+  let files = bookmarksBackupDir.directoryEntries;
+  Assert.ok(!files.hasMoreElements(), "Should have no backup files.");
+  await IOUtils.remove(filePath);
+  // We don't need to call cleanupFiles as we are not creating any
+  // backups but need to reset the cache.
+  delete PlacesBackups._backupFiles;
+});
+
+add_task(async function test_saveBookmarks_with_backups() {
+  let backupFolderPath = await PlacesBackups.getBackupFolder();
+  let bookmarksBackupDir = new FileUtils.File(backupFolderPath);
+
+  Services.prefs.setIntPref("browser.bookmarks.max_backups", NUMBER_OF_BACKUPS);
+
+  let filePath = PathUtils.join(do_get_tempdir().path, "backup.json");
+  let dateObj = new Date();
+  let dates = await createBackups(
+    NUMBER_OF_BACKUPS,
+    dateObj,
+    bookmarksBackupDir
+  );
+
+  await PlacesBackups.saveBookmarksToJSONFile(filePath);
+
+  let backupPath = await PlacesBackups.getMostRecentBackup();
+  Assert.ok(await IOUtils.read(backupPath, { decompress: true }));
+
+  dates.push(dateObj.getTime());
+  await checkBackups(dates, bookmarksBackupDir);
+  await IOUtils.remove(filePath);
+  await cleanupFiles(bookmarksBackupDir);
+});
diff --git a/toolkit/components/places/tests/unit/test_utils_backups_hasRecent.js b/toolkit/components/places/tests/unit/test_utils_backups_hasRecent.js
new file mode 100644
index 0000000000..77d356b032
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_utils_backups_hasRecent.js
@@ -0,0 +1,43 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Check for correct functionality of bookmarks backups
+ */
+
+/**
+ * Creates a fake empty dated backup.
+ * @param {Date} date the Date to use for the backup file name
+ * @param {string} backupsFolderPath the path to the backups folder
+ * @returns path of the created backup file
+ */
+async function createFakeBackup(date, backupsFolderPath) {
+  let backupFilePath = PathUtils.join(
+    backupsFolderPath,
+    PlacesBackups.getFilenameForDate(date)
+  );
+  await IOUtils.write(backupFilePath, new Uint8Array());
+  return backupFilePath;
+}
+
+add_task(async function test_hasRecentBackup() {
+  let backupFolderPath = await PlacesBackups.getBackupFolder();
+  Assert.ok(!(await PlacesBackups.hasRecentBackup()), "Check no recent backup");
+
+  await createFakeBackup(new Date(Date.now() - 4 * 86400), backupFolderPath);
+  Assert.ok(!(await PlacesBackups.hasRecentBackup()), "Check no recent backup");
+  PlacesBackups.invalidateCache();
+  await createFakeBackup(new Date(Date.now() - 2 * 86400), backupFolderPath);
+  Assert.ok(await PlacesBackups.hasRecentBackup(), "Check has recent backup");
+  PlacesBackups.invalidateCache();
+
+  try {
+    await IOUtils.remove(backupFolderPath, { recursive: true });
+  } catch (ex) {
+    // On Windows the files may be locked.
+    info("Unable to cleanup the backups test folder");
+  }
+});
diff --git a/toolkit/components/places/tests/unit/test_utils_getURLsForContainerNode.js b/toolkit/components/places/tests/unit/test_utils_getURLsForContainerNode.js
new file mode 100644
index 0000000000..2d092ef591
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_utils_getURLsForContainerNode.js
@@ -0,0 +1,266 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Check for correct functionality of PlacesUtils.getURLsForContainerNode and
+ * PlacesUtils.hasChildURIs (those helpers share almost all of their code)
+ */
+
+var PU = PlacesUtils;
+var hs = PU.history;
+
+add_task(async function test_getURLsForContainerNode_folder() {
+  info("*** TEST: folder");
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        // This is the folder we will check for children.
+        title: "folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        // Create a folder and a query node inside it, these should not be considered
+        // uri nodes.
+        children: [
+          {
+            title: "inside folder",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            children: [
+              {
+                url: "place:sort=1",
+                title: "inside query",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+
+  var query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = hs.getNewQueryOptions();
+
+  info("Check folder without uri nodes");
+  check_uri_nodes(query, options, 0);
+
+  info("Check folder with uri nodes");
+  // Add an uri node, this should be considered.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: bookmarks[0].guid,
+    url: "http://www.mozilla.org/",
+    title: "bookmark",
+  });
+  check_uri_nodes(query, options, 1);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_getURLsForContainerNode_folder_excludeItems() {
+  info("*** TEST: folder in an excludeItems root");
+  let bookmarks = await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.toolbarGuid,
+    children: [
+      {
+        // This is the folder we will check for children.
+        title: "folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        // Create a folder and a query node inside it, these should not be considered
+        // uri nodes.
+        children: [
+          {
+            title: "inside folder",
+            type: PlacesUtils.bookmarks.TYPE_FOLDER,
+            children: [
+              {
+                url: "place:sort=1",
+                title: "inside query",
+              },
+            ],
+          },
+        ],
+      },
+    ],
+  });
+
+  var query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = hs.getNewQueryOptions();
+  options.excludeItems = true;
+
+  info("Check folder without uri nodes");
+  check_uri_nodes(query, options, 0);
+
+  info("Check folder with uri nodes");
+  // Add an uri node, this should be considered.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: bookmarks[0].guid,
+    url: "http://www.mozilla.org/",
+    title: "bookmark",
+  });
+  check_uri_nodes(query, options, 1);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_getURLsForContainerNode_query() {
+  info("*** TEST: query");
+  // This is the query we will check for children.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "inside query",
+    url: `place:parent=${PlacesUtils.bookmarks.menuGuid}&sort=1`,
+  });
+
+  // Create a folder and a query node inside it, these should not be considered
+  // uri nodes.
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "inside folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            url: "place:sort=1",
+            title: "inside query",
+          },
+        ],
+      },
+    ],
+  });
+
+  var query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = hs.getNewQueryOptions();
+
+  info("Check query without uri nodes");
+  check_uri_nodes(query, options, 0);
+
+  info("Check query with uri nodes");
+  // Add an uri node, this should be considered.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://www.mozilla.org/",
+    title: "bookmark",
+  });
+  check_uri_nodes(query, options, 1);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_getURLsForContainerNode_query_excludeItems() {
+  info("*** TEST: excludeItems Query");
+  // This is the query we will check for children.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "inside query",
+    url: `place:parent=${PlacesUtils.bookmarks.menuGuid}&sort=1`,
+  });
+
+  // Create a folder and a query node inside it, these should not be considered
+  // uri nodes.
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "inside folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            url: "place:sort=1",
+            title: "inside query",
+          },
+        ],
+      },
+    ],
+  });
+
+  var query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = hs.getNewQueryOptions();
+  options.excludeItems = true;
+
+  info("Check folder without uri nodes");
+  check_uri_nodes(query, options, 0);
+
+  info("Check folder with uri nodes");
+  // Add an uri node, this should be considered.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://www.mozilla.org/",
+    title: "bookmark",
+  });
+  check_uri_nodes(query, options, 1);
+
+  await PlacesUtils.bookmarks.eraseEverything();
+});
+
+add_task(async function test_getURLsForContainerNode_query_excludeQueries() {
+  info("*** TEST: !expandQueries Query");
+  // This is the query we will check for children.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.toolbarGuid,
+    title: "inside query",
+    url: `place:parent=${PlacesUtils.bookmarks.menuGuid}&sort=1`,
+  });
+
+  // Create a folder and a query node inside it, these should not be considered
+  // uri nodes.
+  await PlacesUtils.bookmarks.insertTree({
+    guid: PlacesUtils.bookmarks.menuGuid,
+    children: [
+      {
+        title: "inside folder",
+        type: PlacesUtils.bookmarks.TYPE_FOLDER,
+        children: [
+          {
+            url: "place:sort=1",
+            title: "inside query",
+          },
+        ],
+      },
+    ],
+  });
+
+  var query = hs.getNewQuery();
+  query.setParents([PlacesUtils.bookmarks.toolbarGuid]);
+  var options = hs.getNewQueryOptions();
+  options.expandQueries = false;
+
+  info("Check folder without uri nodes");
+  check_uri_nodes(query, options, 0);
+
+  info("Check folder with uri nodes");
+  // Add an uri node, this should be considered.
+  await PlacesUtils.bookmarks.insert({
+    parentGuid: PlacesUtils.bookmarks.menuGuid,
+    url: "http://www.mozilla.org/",
+    title: "bookmark",
+  });
+  check_uri_nodes(query, options, 1);
+});
+
+/**
+ * Executes a query and checks number of uri nodes in the first container in
+ * query's results.  To correctly test a container ensure that the query will
+ * return only your container in the first level.
+ *
+ * @param  aQuery
+ *         nsINavHistoryQuery object defining the query
+ * @param  aOptions
+ *         nsINavHistoryQueryOptions object defining the query's options
+ * @param  aExpectedURINodes
+ *         number of expected uri nodes
+ */
+function check_uri_nodes(aQuery, aOptions, aExpectedURINodes) {
+  var result = hs.executeQuery(aQuery, aOptions);
+  var root = result.root;
+  root.containerOpen = true;
+  var node = root.getChild(0);
+  Assert.equal(PU.hasChildURIs(node), aExpectedURINodes > 0);
+  Assert.equal(PU.getURLsForContainerNode(node).length, aExpectedURINodes);
+  root.containerOpen = false;
+}
diff --git a/toolkit/components/places/tests/unit/test_utils_timeConversion.js b/toolkit/components/places/tests/unit/test_utils_timeConversion.js
new file mode 100644
index 0000000000..c71effe709
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_utils_timeConversion.js
@@ -0,0 +1,51 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Check time conversion utils.
+ */
+
+add_task(async function toDate() {
+  Assert.throws(() => PlacesUtils.toDate(), /Invalid value/, "Should throw");
+  Assert.throws(() => PlacesUtils.toDate(NaN), /Invalid value/, "Should throw");
+  Assert.throws(
+    () => PlacesUtils.toDate(null),
+    /Invalid value/,
+    "Should throw"
+  );
+  Assert.throws(() => PlacesUtils.toDate("1"), /Invalid value/, "Should throw");
+
+  const now = Date.now();
+  const usecs = now * 1000;
+  Assert.deepEqual(PlacesUtils.toDate(usecs), new Date(now));
+});
+
+add_task(async function toPRTime() {
+  Assert.throws(() => PlacesUtils.toPRTime(), /TypeError/, "Should throw");
+  Assert.throws(() => PlacesUtils.toPRTime(null), /TypeError/, "Should throw");
+  Assert.throws(
+    () => PlacesUtils.toPRTime({}),
+    /Invalid value/,
+    "Should throw"
+  );
+  Assert.throws(
+    () => PlacesUtils.toPRTime(NaN),
+    /Invalid value/,
+    "Should throw"
+  );
+  Assert.throws(
+    () => PlacesUtils.toPRTime(new Date(NaN)),
+    /Invalid value/,
+    "Should throw"
+  );
+  Assert.throws(
+    () => PlacesUtils.toPRTime(new URL("https://test.moz")),
+    /Invalid value/,
+    "Should throw"
+  );
+
+  const now = Date.now();
+  const usecs = now * 1000;
+  Assert.strictEqual(PlacesUtils.toPRTime(now), usecs);
+  Assert.strictEqual(PlacesUtils.toPRTime(new Date(now)), usecs);
+});
diff --git a/toolkit/components/places/tests/unit/test_visitsInDB.js b/toolkit/components/places/tests/unit/test_visitsInDB.js
new file mode 100644
index 0000000000..cbd0a04c4b
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_visitsInDB.js
@@ -0,0 +1,12 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+add_task(async function test_execute() {
+  const TEST_URI = uri("http://mozilla.com");
+
+  Assert.equal(0, await PlacesTestUtils.visitsInDB(TEST_URI));
+  await PlacesTestUtils.addVisits({ uri: TEST_URI });
+  Assert.equal(1, await PlacesTestUtils.visitsInDB(TEST_URI));
+  await PlacesTestUtils.addVisits({ uri: TEST_URI });
+  Assert.equal(2, await PlacesTestUtils.visitsInDB(TEST_URI));
+});
diff --git a/toolkit/components/places/tests/unit/xpcshell.toml b/toolkit/components/places/tests/unit/xpcshell.toml
new file mode 100644
index 0000000000..750e8ad9ea
--- /dev/null
+++ b/toolkit/components/places/tests/unit/xpcshell.toml
@@ -0,0 +1,210 @@
+[DEFAULT]
+head = "head_bookmarks.js"
+firefox-appdir = "browser"
+prefs = ["places.loglevel='All'"]
+support-files = [
+  "bookmarks.corrupt.html",
+  "bookmarks.json",
+  "bookmarks_corrupt.json",
+  "bookmarks.preplaces.html",
+  "bookmarks_html_localized.html",
+  "bookmarks_html_singleframe.html",
+  "bookmarks_iconuri.json",
+  "mobile_bookmarks_folder_import.json",
+  "mobile_bookmarks_folder_merge.json",
+  "mobile_bookmarks_multiple_folders.json",
+  "mobile_bookmarks_root_import.json",
+  "mobile_bookmarks_root_merge.json",
+]
+
+["test_1085291.js"]
+
+["test_1105208.js"]
+
+["test_1105866.js"]
+
+["test_1606731.js"]
+
+["test_331487.js"]
+
+["test_384370.js"]
+
+["test_385397.js"]
+
+["test_399266.js"]
+skip-if = ["os == 'linux'"] # Bug 821781
+
+["test_402799.js"]
+
+["test_412132.js"]
+
+["test_415460.js"]
+
+["test_415757.js"]
+
+["test_419792_node_tags_property.js"]
+
+["test_425563.js"]
+
+["test_429505_remove_shortcuts.js"]
+
+["test_433317_query_title_update.js"]
+
+["test_433525_hasChildren_crash.js"]
+
+["test_454977.js"]
+
+["test_463863.js"]
+
+["test_485442_crash_bug_nsNavHistoryQuery_GetUri.js"]
+
+["test_486978_sort_by_date_queries.js"]
+
+["test_536081.js"]
+
+["test_PlacesDBUtils_removeOldCorruptDBs.js"]
+
+["test_PlacesQuery_history.js"]
+
+["test_PlacesUtils_isRootItem.js"]
+
+["test_PlacesUtils_unwrapNodes_place.js"]
+
+["test_asyncExecuteLegacyQueries.js"]
+
+["test_async_transactions.js"]
+
+["test_autocomplete_match_fallbackTitle.js"]
+
+["test_bookmark-tags-changed_frequency.js"]
+
+["test_bookmarks_html.js"]
+
+["test_bookmarks_html_corrupt.js"]
+
+["test_bookmarks_html_escape_entities.js"]
+
+["test_bookmarks_html_import_tags.js"]
+
+["test_bookmarks_html_localized.js"]
+
+["test_bookmarks_html_singleframe.js"]
+
+["test_bookmarks_json.js"]
+
+["test_bookmarks_json_corrupt.js"]
+
+["test_bookmarks_restore_notification.js"]
+
+["test_broken_folderShortcut_result.js"]
+
+["test_browserhistory.js"]
+
+["test_childlessTags.js"]
+
+["test_frecency_decay.js"]
+
+["test_frecency_observers.js"]
+
+["test_frecency_origins_alternative.js"]
+
+["test_frecency_origins_recalc.js"]
+prefs = ["places.frecency.origins.alternative.featureGate=true"]
+
+["test_frecency_pages_alternative.js"]
+prefs = ["places.frecency.pages.alternative.featureGate=true"]
+
+["test_frecency_pages_recalc_alt.js"]
+prefs = ["places.frecency.pages.alternative.featureGate=true"]
+
+["test_frecency_recalc_triggers.js"]
+
+["test_frecency_recalculator.js"]
+
+["test_frecency_unvisited_bookmark.js"]
+
+["test_frecency_zero_updated.js"]
+
+["test_getChildIndex.js"]
+
+["test_get_query_param_sql_function.js"]
+
+["test_hash.js"]
+
+["test_history.js"]
+
+["test_history_clear.js"]
+
+["test_history_notifications.js"]
+
+["test_history_observer.js"]
+
+["test_history_sidebar.js"]
+
+["test_import_mobile_bookmarks.js"]
+
+["test_isPageInDB.js"]
+
+["test_isURIVisited.js"]
+
+["test_isvisited.js"]
+
+["test_keywords.js"]
+
+["test_lastModified.js"]
+
+["test_markpageas.js"]
+
+["test_metadata.js"]
+
+["test_missing_builtin_folders.js"]
+
+["test_missing_root_folder.js"]
+
+["test_multi_observation.js"]
+
+["test_multi_word_tags.js"]
+
+["test_nested_notifications.js"]
+
+["test_nsINavHistoryViewer.js"]
+
+["test_null_interfaces.js"]
+
+["test_origins.js"]
+
+["test_origins_parsing.js"]
+
+["test_pageGuid_bookmarkGuid.js"]
+
+["test_placeURIs.js"]
+
+["test_promiseBookmarksTree.js"]
+
+["test_resolveNullBookmarkTitles.js"]
+
+["test_result_sort.js"]
+
+["test_resultsAsVisit_details.js"]
+
+["test_sql_function_origin.js"]
+
+["test_sql_guid_functions.js"]
+
+["test_tag_autocomplete_search.js"]
+
+["test_tagging.js"]
+
+["test_telemetry.js"]
+
+["test_update_frecency_after_delete.js"]
+
+["test_utils_backups_create.js"]
+
+["test_utils_backups_hasRecent.js"]
+
+["test_utils_getURLsForContainerNode.js"]
+
+["test_utils_timeConversion.js"]
+
+["test_visitsInDB.js"]