Adding upstream version 115.8.0esr.upstream/115.8.0esr

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

36 files changed, 6990 insertions, 0 deletions

diff --git a/toolkit/components/prompts/content/adjustableTitle.js b/toolkit/components/prompts/content/adjustableTitle.js
new file mode 100644
index 0000000000..bd9afd909a
--- /dev/null
+++ b/toolkit/components/prompts/content/adjustableTitle.js
@@ -0,0 +1,193 @@
+/* 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";
+
+let { PromptUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PromptUtils.sys.mjs"
+);
+
+const AdjustableTitle = {
+  _cssSnippet: `
+    #titleContainer {
+      /* This gets display: flex by virtue of being a row in a subdialog, from
+        * commonDialog.css . */
+      flex-shrink: 0;
+
+      flex-direction: row;
+      align-items: baseline;
+
+      margin-inline: 4px;
+      /* Ensure we don't exceed the bounds of the dialog: */
+      max-width: calc(100vw - 32px);
+
+      --icon-size: 16px;
+    }
+
+    #titleContainer[noicon] > .titleIcon {
+      display: none;
+    }
+
+    .titleIcon {
+      width: var(--icon-size);
+      height: var(--icon-size);
+      padding-inline-end: 4px;
+      flex-shrink: 0;
+
+      background-image: var(--icon-url, url("chrome://global/skin/icons/defaultFavicon.svg"));
+      background-size: 16px 16px;
+      background-origin: content-box;
+      background-repeat: no-repeat;
+      background-color: var(--in-content-page-background);
+      -moz-context-properties: fill;
+      fill: currentColor;
+    }
+
+    #titleCropper:not([nomaskfade]) {
+      display: inline-flex;
+    }
+
+    #titleCropper {
+      overflow: hidden;
+
+      justify-content: right;
+      mask-repeat: no-repeat;
+      /* go from left to right with the mask: */
+      --mask-dir: right;
+    }
+
+    #titleContainer:not([noicon]) > #titleCropper {
+      /* Align the icon and text: */
+      translate: 0 calc(-1px - max(.6 * var(--icon-size) - .6em, 0px));
+    }
+
+    #titleCropper[rtlorigin] {
+      justify-content: left;
+      /* go from right to left with the mask: */
+      --mask-dir: left;
+    }
+
+
+    #titleCropper:not([nomaskfade]) #titleText {
+      display: inline-flex;
+      white-space: nowrap;
+    }
+
+    #titleText {
+      font-weight: 600;
+      flex: 1 0 auto; /* Grow but do not shrink. */
+      unicode-bidi: plaintext; /* Ensure we align RTL text correctly. */
+      text-align: match-parent;
+    }
+
+    #titleCropper[overflown] {
+      mask-image: linear-gradient(to var(--mask-dir), transparent, black 100px);
+    }
+
+    /* hide the old title */
+    #infoTitle {
+      display: none;
+    }
+   `,
+
+  _insertMarkup() {
+    let iconEl = document.createElement("span");
+    iconEl.className = "titleIcon";
+    this._titleCropEl = document.createElement("span");
+    this._titleCropEl.id = "titleCropper";
+    this._titleEl = document.createElement("span");
+    this._titleEl.id = "titleText";
+    this._containerEl = document.createElement("div");
+    this._containerEl.id = "titleContainer";
+    this._containerEl.className = "dialogRow titleContainer";
+    this._titleCropEl.append(this._titleEl);
+    this._containerEl.append(iconEl, this._titleCropEl);
+    let targetID = document.documentElement.getAttribute("headerparent");
+    document.getElementById(targetID).prepend(this._containerEl);
+    let styleEl = document.createElement("style");
+    styleEl.textContent = this._cssSnippet;
+    document.documentElement.prepend(styleEl);
+  },
+
+  _overflowHandler() {
+    requestAnimationFrame(async () => {
+      let isOverflown;
+      try {
+        isOverflown = await window.promiseDocumentFlushed(() => {
+          return (
+            this._titleCropEl.getBoundingClientRect().width <
+            this._titleEl.getBoundingClientRect().width
+          );
+        });
+      } catch (ex) {
+        // In automated tests, this can fail with a DOM exception if
+        // the window has closed by the time layout tries to call us.
+        // In this case, just bail, and only log any other errors:
+        if (
+          !DOMException.isInstance(ex) ||
+          ex.name != "NoModificationAllowedError"
+        ) {
+          console.error(ex);
+        }
+        return;
+      }
+      this._titleCropEl.toggleAttribute("overflown", isOverflown);
+      if (isOverflown) {
+        this._titleEl.setAttribute("title", this._titleEl.textContent);
+      } else {
+        this._titleEl.removeAttribute("title");
+      }
+    });
+  },
+
+  _updateTitle(title) {
+    title = JSON.parse(title);
+    if (title.raw) {
+      this._titleEl.textContent = title.raw;
+      let { DIRECTION_RTL } = window.windowUtils;
+      this._titleCropEl.toggleAttribute(
+        "rtlorigin",
+        window.windowUtils.getDirectionFromText(title.raw) == DIRECTION_RTL
+      );
+    } else {
+      document.l10n.setAttributes(this._titleEl, title.l10nId);
+    }
+
+    if (!document.documentElement.hasAttribute("neediconheader")) {
+      this._containerEl.setAttribute("noicon", "true");
+    } else if (title.shouldUseMaskFade) {
+      this._overflowHandler();
+    } else {
+      this._titleCropEl.toggleAttribute("nomaskfade", true);
+    }
+  },
+
+  init() {
+    // Only run this if we're embedded and proton modals are enabled.
+    if (!window.docShell.chromeEventHandler) {
+      return;
+    }
+
+    this._insertMarkup();
+    let title = document.documentElement.getAttribute("headertitle");
+    if (title) {
+      this._updateTitle(title);
+    }
+    this._mutObs = new MutationObserver(() => {
+      this._updateTitle(document.documentElement.getAttribute("headertitle"));
+    });
+    this._mutObs.observe(document.documentElement, {
+      attributes: true,
+      attributeFilter: ["headertitle"],
+    });
+  },
+};
+
+document.addEventListener(
+  "DOMContentLoaded",
+  () => {
+    AdjustableTitle.init();
+  },
+  { once: true }
+);
diff --git a/toolkit/components/prompts/content/commonDialog.css b/toolkit/components/prompts/content/commonDialog.css
new file mode 100644
index 0000000000..3521af13c6
--- /dev/null
+++ b/toolkit/components/prompts/content/commonDialog.css
@@ -0,0 +1,124 @@
+/* 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/. */
+
+:root {
+  min-width: 29em;
+}
+
+dialog[insecureauth] {
+  --icon-url: url("chrome://global/skin/icons/security-broken.svg");
+}
+
+#dialogGrid {
+  display: grid;
+  grid-template-columns: auto 1fr;
+  align-items: center;
+  max-height: 100%;
+}
+
+.dialogRow:not([hidden]) {
+  display: contents;
+}
+
+#iconContainer {
+  align-self: start;
+}
+
+#infoContainer {
+  max-width: 45em;
+}
+
+#infoTitle {
+  margin-bottom: 1em;
+}
+
+#infoBody {
+  -moz-user-focus: normal;
+  user-select: text;
+  cursor: text !important;
+  white-space: pre-wrap;
+  word-break: break-word;
+  unicode-bidi: plaintext;
+  overflow-y: auto;
+}
+
+.sizeDetermined,
+.sizeDetermined::part(content-box),
+.sizeDetermined #infoBody,
+.sizeDetermined #infoRow,
+.sizeDetermined #infoContainer {
+  /* Allow stuff to shrink */
+  min-height: 0;
+}
+
+.sizeDetermined #infoRow {
+  /* Make the info row take all the available space, potentially shrinking,
+   * since it's what contains the infoBody, which is scrollable */
+  flex: 1;
+}
+
+#loginLabel, #password1Label {
+  text-align: start;
+}
+
+#loginTextbox,
+#password1Textbox {
+  text-align: match-parent;
+}
+
+/* use flexbox instead of grid: */
+dialog[subdialog],
+dialog[subdialog] #dialogGrid,
+dialog[subdialog] #infoContainer,
+dialog[subdialog] .dialogRow:not([hidden]) {
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+}
+
+dialog[subdialog] #iconContainer {
+  display: none;
+}
+
+/* Fix padding/spacing */
+dialog[subdialog] {
+  --grid-padding: 16px;
+  /* All the inner items should have 4px inline margin, leading to 1.16em spacing
+   * between the dialog and its contents, and 8px horizontal spacing between items. */
+  padding: var(--grid-padding) calc(var(--grid-padding) - 4px);
+}
+
+/* Use an ID selector for the dialog to win on specificity... */
+#commonDialog[subdialog] description,
+#commonDialog[subdialog] checkbox {
+  margin: 0 4px;
+}
+
+#commonDialog[subdialog] label {
+  margin: 4px; /* Labels for input boxes should get block as well as the regular inline margin. */
+}
+
+#commonDialog[subdialog] .checkbox-label {
+  /* The checkbox already has the horizontal margin, so override the rule
+   * above. */
+  margin: 0;
+}
+
+#commonDialog[subdialog] input {
+  margin: 0 4px 4px;
+}
+
+/* Add vertical spaces between rows: */
+dialog[subdialog] .dialogRow {
+  margin-block: 0 var(--grid-padding);
+}
+
+/* Fix spacing in the `prompt()` case: */
+dialog[subdialog] #loginLabel[value=""] {
+  display: none;
+}
+
+dialog[subdialog][windowtype="prompt:prompt"] #infoRow {
+  margin-bottom: 4px;
+}
diff --git a/toolkit/components/prompts/content/commonDialog.js b/toolkit/components/prompts/content/commonDialog.js
new file mode 100644
index 0000000000..a18b7cbd6c
--- /dev/null
+++ b/toolkit/components/prompts/content/commonDialog.js
@@ -0,0 +1,148 @@
+/* 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 { CommonDialog } = ChromeUtils.importESModule(
+  "resource://gre/modules/CommonDialog.sys.mjs"
+);
+
+// imported by adjustableTitle.js loaded in the same context:
+/* globals PromptUtils */
+
+var propBag, args, Dialog;
+
+// Inherit color scheme overrides from parent window. This is to inherit the
+// color scheme of dark themed PBM windows.
+{
+  let openerColorSchemeOverride =
+    window.opener?.browsingContext?.top.prefersColorSchemeOverride;
+  if (
+    openerColorSchemeOverride &&
+    window.browsingContext == window.browsingContext.top
+  ) {
+    window.browsingContext.prefersColorSchemeOverride =
+      openerColorSchemeOverride;
+  }
+}
+
+function commonDialogOnLoad() {
+  propBag = window.arguments[0]
+    .QueryInterface(Ci.nsIWritablePropertyBag2)
+    .QueryInterface(Ci.nsIWritablePropertyBag);
+  // Convert to a JS object
+  args = {};
+  for (let prop of propBag.enumerator) {
+    args[prop.name] = prop.value;
+  }
+
+  let dialog = document.getElementById("commonDialog");
+
+  let needIconifiedHeader =
+    args.modalType == Ci.nsIPrompt.MODAL_TYPE_CONTENT ||
+    ["promptUserAndPass", "promptPassword"].includes(args.promptType) ||
+    args.headerIconURL;
+  let root = document.documentElement;
+  if (needIconifiedHeader) {
+    root.setAttribute("neediconheader", "true");
+  }
+  let title = { raw: args.title };
+  let { promptPrincipal } = args;
+  if (promptPrincipal) {
+    if (promptPrincipal.isNullPrincipal) {
+      title = { l10nId: "common-dialog-title-null" };
+    } else if (promptPrincipal.isSystemPrincipal) {
+      title = { l10nId: "common-dialog-title-system" };
+      root.style.setProperty(
+        "--icon-url",
+        "url('chrome://branding/content/icon32.png')"
+      );
+    } else if (promptPrincipal.addonPolicy) {
+      title.raw = promptPrincipal.addonPolicy.name;
+    } else if (promptPrincipal.isContentPrincipal) {
+      try {
+        title.raw = promptPrincipal.URI.displayHostPort;
+      } catch (ex) {
+        // hostPort getter can throw, e.g. for about URIs.
+        title.raw = promptPrincipal.originNoSuffix;
+      }
+      // hostPort can be empty for file URIs.
+      if (!title.raw) {
+        title.raw = promptPrincipal.prePath;
+      }
+    } else {
+      title = { l10nId: "common-dialog-title-unknown" };
+    }
+  } else if (args.authOrigin) {
+    title = { raw: args.authOrigin };
+  }
+  if (args.headerIconURL) {
+    root.style.setProperty("--icon-url", `url('${args.headerIconURL}')`);
+  }
+  // Fade and crop potentially long raw titles, e.g., origins and hostnames.
+  title.shouldUseMaskFade = title.raw && (args.authOrigin || promptPrincipal);
+  root.setAttribute("headertitle", JSON.stringify(title));
+  if (args.isInsecureAuth) {
+    dialog.setAttribute("insecureauth", "true");
+  }
+
+  let ui = {
+    prompt: window,
+    loginContainer: document.getElementById("loginContainer"),
+    loginTextbox: document.getElementById("loginTextbox"),
+    loginLabel: document.getElementById("loginLabel"),
+    password1Container: document.getElementById("password1Container"),
+    password1Textbox: document.getElementById("password1Textbox"),
+    password1Label: document.getElementById("password1Label"),
+    infoRow: document.getElementById("infoRow"),
+    infoBody: document.getElementById("infoBody"),
+    infoTitle: document.getElementById("infoTitle"),
+    infoIcon: document.getElementById("infoIcon"),
+    checkbox: document.getElementById("checkbox"),
+    checkboxContainer: document.getElementById("checkboxContainer"),
+    button3: dialog.getButton("extra2"),
+    button2: dialog.getButton("extra1"),
+    button1: dialog.getButton("cancel"),
+    button0: dialog.getButton("accept"),
+    focusTarget: window,
+  };
+
+  Dialog = new CommonDialog(args, ui);
+  window.addEventListener("dialogclosing", function (aEvent) {
+    if (aEvent.detail?.abort) {
+      Dialog.abortPrompt();
+    }
+  });
+  document.addEventListener("dialogaccept", function () {
+    Dialog.onButton0();
+  });
+  document.addEventListener("dialogcancel", function () {
+    Dialog.onButton1();
+  });
+  document.addEventListener("dialogextra1", function () {
+    Dialog.onButton2();
+    window.close();
+  });
+  document.addEventListener("dialogextra2", function () {
+    Dialog.onButton3();
+    window.close();
+  });
+  document.subDialogSetDefaultFocus = isInitialFocus =>
+    Dialog.setDefaultFocus(isInitialFocus);
+  Dialog.onLoad(dialog);
+
+  // resize the window to the content
+  window.sizeToContent();
+
+  // If the icon hasn't loaded yet, size the window to the content again when
+  // it does, as its layout can change.
+  ui.infoIcon.addEventListener("load", () => window.sizeToContent());
+
+  window.getAttention();
+}
+
+function commonDialogOnUnload() {
+  // Convert args back into property bag
+  for (let propName in args) {
+    propBag.setProperty(propName, args[propName]);
+  }
+}
diff --git a/toolkit/components/prompts/content/commonDialog.xhtml b/toolkit/components/prompts/content/commonDialog.xhtml
new file mode 100644
index 0000000000..02e0749a9e
--- /dev/null
+++ b/toolkit/components/prompts/content/commonDialog.xhtml
@@ -0,0 +1,103 @@
+<?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/. -->
+
+<?xml-stylesheet href="chrome://global/skin/global.css" type="text/css"?>
+<?xml-stylesheet href="chrome://global/content/commonDialog.css" type="text/css"?>
+<?xml-stylesheet href="chrome://global/skin/commonDialog.css" type="text/css"?>
+
+<!DOCTYPE window>
+
+<window
+  id="commonDialogWindow"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  aria-describedby="infoBody"
+  headerparent="dialogGrid"
+  onunload="commonDialogOnUnload();"
+>
+  <dialog id="commonDialog" buttonpack="end">
+    <linkset>
+      <html:link rel="localization" href="branding/brand.ftl" />
+      <html:link rel="localization" href="toolkit/global/commonDialog.ftl" />
+    </linkset>
+    <script src="chrome://global/content/adjustableTitle.js" />
+    <script src="chrome://global/content/commonDialog.js" />
+    <script src="chrome://global/content/globalOverlay.js" />
+    <script src="chrome://global/content/editMenuOverlay.js" />
+    <script src="chrome://global/content/customElements.js" />
+    <script>
+      /* eslint-disable no-undef */
+      document.addEventListener("DOMContentLoaded", function () {
+        commonDialogOnLoad();
+      });
+    </script>
+
+    <commandset id="selectEditMenuItems">
+      <command
+        id="cmd_copy"
+        oncommand="goDoCommand('cmd_copy')"
+        disabled="true"
+      />
+      <command id="cmd_selectAll" oncommand="goDoCommand('cmd_selectAll')" />
+    </commandset>
+
+    <popupset id="contentAreaContextSet">
+      <menupopup
+        id="contentAreaContextMenu"
+        onpopupshowing="goUpdateCommand('cmd_copy')"
+      >
+        <menuitem
+          id="context-copy"
+          data-l10n-id="common-dialog-copy-cmd"
+          command="cmd_copy"
+          disabled="true"
+        />
+        <menuitem
+          id="context-selectall"
+          data-l10n-id="common-dialog-select-all-cmd"
+          command="cmd_selectAll"
+        />
+      </menupopup>
+    </popupset>
+
+    <div xmlns="http://www.w3.org/1999/xhtml" id="dialogGrid">
+      <div class="dialogRow" id="infoRow" hidden="hidden">
+        <div id="iconContainer">
+          <xul:image id="infoIcon" />
+        </div>
+        <div id="infoContainer">
+          <xul:description id="infoTitle" />
+          <xul:description
+            id="infoBody"
+            context="contentAreaContextMenu"
+            noinitialfocus="true"
+          />
+        </div>
+      </div>
+      <div id="loginContainer" class="dialogRow" hidden="hidden">
+        <xul:label
+          id="loginLabel"
+          data-l10n-id="common-dialog-username"
+          control="loginTextbox"
+        />
+        <input type="text" id="loginTextbox" dir="ltr" />
+      </div>
+      <div id="password1Container" class="dialogRow" hidden="hidden">
+        <xul:label
+          id="password1Label"
+          data-l10n-id="common-dialog-password"
+          control="password1Textbox"
+        />
+        <input type="password" id="password1Textbox" dir="ltr" />
+      </div>
+      <div id="checkboxContainer" class="dialogRow" hidden="hidden">
+        <div />
+        <!-- spacer -->
+        <xul:checkbox id="checkbox" oncommand="Dialog.onCheckbox()" />
+      </div>
+    </div>
+  </dialog>
+</window>
diff --git a/toolkit/components/prompts/content/selectDialog.js b/toolkit/components/prompts/content/selectDialog.js
new file mode 100644
index 0000000000..86809bc879
--- /dev/null
+++ b/toolkit/components/prompts/content/selectDialog.js
@@ -0,0 +1,83 @@
+/* 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/. */
+
+// Defined in dialog.xml.
+/* globals centerWindowOnScreen:false, moveToAlertPosition:false */
+
+var propBag, listBox, args;
+
+function onDCL() {
+  propBag = window.arguments[0]
+    .QueryInterface(Ci.nsIWritablePropertyBag2)
+    .QueryInterface(Ci.nsIWritablePropertyBag);
+
+  // Convert to a JS object
+  let args = {};
+  for (let prop of propBag.enumerator) {
+    args[prop.name] = prop.value;
+  }
+
+  let promptType = propBag.getProperty("promptType");
+  if (promptType != "select") {
+    console.error("selectDialog opened for unknown type: ", promptType);
+    window.close();
+  }
+
+  // Default to canceled.
+  propBag.setProperty("ok", false);
+
+  document.title = propBag.getProperty("title");
+
+  let text = propBag.getProperty("text");
+  document.getElementById("info.txt").setAttribute("value", text);
+
+  let items = propBag.getProperty("list");
+  listBox = document.getElementById("list");
+
+  for (let i = 0; i < items.length; i++) {
+    let str = items[i];
+    if (str == "") {
+      str = "<>";
+    }
+    listBox.appendItem(str);
+    listBox.getItemAtIndex(i).addEventListener("dblclick", dialogDoubleClick);
+  }
+  listBox.selectedIndex = 0;
+}
+
+function onLoad() {
+  listBox.focus();
+
+  document.addEventListener("dialogaccept", dialogOK);
+  // resize the window to the content
+  window.sizeToContent();
+
+  // Move to the right location
+  moveToAlertPosition();
+  centerWindowOnScreen();
+
+  // play sound
+  try {
+    if (!args.openedWithTabDialog) {
+      Cc["@mozilla.org/sound;1"]
+        .getService(Ci.nsISound)
+        .playEventSound(Ci.nsISound.EVENT_SELECT_DIALOG_OPEN);
+    }
+  } catch (e) {}
+
+  Services.obs.notifyObservers(window, "select-dialog-loaded");
+}
+
+function dialogOK() {
+  propBag.setProperty("selected", listBox.selectedIndex);
+  propBag.setProperty("ok", true);
+}
+
+function dialogDoubleClick() {
+  dialogOK();
+  window.close();
+}
+
+document.addEventListener("DOMContentLoaded", onDCL);
+window.addEventListener("load", onLoad, { once: true });
diff --git a/toolkit/components/prompts/content/selectDialog.xhtml b/toolkit/components/prompts/content/selectDialog.xhtml
new file mode 100644
index 0000000000..27963ebd57
--- /dev/null
+++ b/toolkit/components/prompts/content/selectDialog.xhtml
@@ -0,0 +1,21 @@
+<?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/. -->
+
+<?xml-stylesheet href="chrome://global/skin/global.css" type="text/css"?>
+<!DOCTYPE window>
+
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <dialog>
+    <script src="chrome://global/content/selectDialog.js" />
+    <keyset id="dialogKeys" />
+    <vbox style="width: 24em; margin: 5px">
+      <label id="info.txt" />
+      <vbox>
+        <richlistbox id="list" class="theme-listbox" style="height: 8em" />
+      </vbox>
+    </vbox>
+  </dialog>
+</window>
diff --git a/toolkit/components/prompts/content/tabprompts.css b/toolkit/components/prompts/content/tabprompts.css
new file mode 100644
index 0000000000..539e8792cc
--- /dev/null
+++ b/toolkit/components/prompts/content/tabprompts.css
@@ -0,0 +1,119 @@
+/* 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/. */
+
+/* Tab Modal Prompt boxes */
+
+.tabModalBackground {
+  justify-content: center;
+  flex-direction: column;
+}
+
+.tabModalBackground,
+tabmodalprompt {
+  width: 100%;
+  height: 100%;
+}
+
+tabmodalprompt {
+  --tabmodalprompt-padding: 20px;
+  overflow: hidden;
+  text-shadow: none; /* remove lightweight theme text-shadow */
+}
+
+tabmodalprompt:not([hidden]) {
+  display: grid;
+  grid-template-rows: 1fr [dialog-start] auto [dialog-end] 2fr;
+  justify-items: center;
+}
+
+/*
+  Adjustments for chrome level tab-prompts to make them
+  overlap with the upper chrome UI and move them in
+  front of content prompts.
+*/
+tabmodalprompt.tab-prompt {
+  overflow: visible;
+  z-index: 1;
+  grid-template-rows: [dialog-start] auto [dialog-end] 1fr;
+}
+
+tabmodalprompt.tab-prompt .tabmodalprompt-mainContainer {
+  margin-top: -5px;
+}
+
+.tabmodalprompt-mainContainer {
+  min-width: 20em;
+  min-height: 12em;
+  max-width: calc(60% + calc(var(--tabmodalprompt-padding) * 2));
+  -moz-user-focus: normal;
+  grid-row: dialog;
+
+  display: flex;
+  flex-direction: column;
+}
+
+.tabmodalprompt-topContainer {
+  flex-grow: 1;
+  padding: var(--tabmodalprompt-padding);
+  display: grid;
+  grid-template-columns: auto 1fr;
+  align-items: baseline;
+  align-content: center; /* center content vertically */
+  max-width: 100%;
+  min-height: 0;
+  max-height: 60vh;
+  box-sizing: border-box;
+}
+
+.tabmodalprompt-topContainer > div:not(.tabmodalprompt-infoContainer, [hidden]) {
+  display: contents;
+}
+
+.tabmodalprompt-infoContainer {
+  grid-column: span 2;
+
+  display: block;
+  margin-block: auto;
+  max-width: 100%;
+  height: 100%;
+  min-height: 0;
+  justify-self: center; /* center text, but only when it fits in one line */
+}
+
+/* When all elements in the first column are hidden, prevent the second column
+   from becoming the first one because it won't have the right fraction */
+.tabmodalprompt-topContainer > div > *:nth-child(2) {
+  grid-column: 2;
+}
+
+.infoTitle {
+  margin-bottom: 1em !important;
+  font-weight: bold;
+}
+
+.infoBody {
+  margin: 0 !important;
+  -moz-user-focus: normal;
+  user-select: text;
+  cursor: text !important;
+  white-space: pre-wrap;
+  unicode-bidi: plaintext;
+  outline: none; /* remove focus outline */
+  overflow: auto;
+  max-width: 100%;
+  max-height: 100%;
+}
+
+tabmodalprompt label[value=""] {
+  display: none;
+}
+
+.tabmodalprompt-buttonContainer {
+  display: flex;
+  padding: 12px var(--tabmodalprompt-padding) 15px;
+}
+
+.tabmodalprompt-buttonSpacer {
+  flex-grow: 1;
+}
diff --git a/toolkit/components/prompts/content/tabprompts.sys.mjs b/toolkit/components/prompts/content/tabprompts.sys.mjs
new file mode 100644
index 0000000000..7edb024fa8
--- /dev/null
+++ b/toolkit/components/prompts/content/tabprompts.sys.mjs
@@ -0,0 +1,298 @@
+/* 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";
+
+export var TabModalPrompt = class {
+  constructor(win) {
+    this.win = win;
+    let newPrompt = (this.element =
+      win.document.createElement("tabmodalprompt"));
+    win.MozXULElement.insertFTLIfNeeded("toolkit/global/tabprompts.ftl");
+    newPrompt.setAttribute("role", "dialog");
+    let randomIdSuffix = Math.random().toString(32).substring(2);
+    newPrompt.setAttribute("aria-describedby", `infoBody-${randomIdSuffix}`);
+    newPrompt.appendChild(
+      win.MozXULElement.parseXULToFragment(
+        `
+        <div class="tabmodalprompt-mainContainer" xmlns="http://www.w3.org/1999/xhtml" xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+          <div class="tabmodalprompt-topContainer">
+            <div class="tabmodalprompt-infoContainer">
+              <div class="tabmodalprompt-infoTitle infoTitle" hidden="hidden"/>
+              <div class="tabmodalprompt-infoBody infoBody" id="infoBody-${randomIdSuffix}" tabindex="-1"/>
+            </div>
+
+            <div class="tabmodalprompt-loginContainer" hidden="hidden">
+              <xul:label class="tabmodalprompt-loginLabel" data-l10n-id="tabmodalprompt-username" control="loginTextbox-${randomIdSuffix}"/>
+              <input class="tabmodalprompt-loginTextbox" id="loginTextbox-${randomIdSuffix}"/>
+            </div>
+
+            <div class="tabmodalprompt-password1Container" hidden="hidden">
+              <xul:label class="tabmodalprompt-password1Label" data-l10n-id="tabmodalprompt-password" control="password1Textbox-${randomIdSuffix}"/>
+              <input class="tabmodalprompt-password1Textbox" type="password" id="password1Textbox-${randomIdSuffix}"/>
+            </div>
+
+            <div class="tabmodalprompt-checkboxContainer" hidden="hidden">
+              <div/>
+              <xul:checkbox class="tabmodalprompt-checkbox"/>
+            </div>
+
+            <!-- content goes here -->
+          </div>
+          <div class="tabmodalprompt-buttonContainer">
+            <xul:button class="tabmodalprompt-button3" hidden="true"/>
+            <div class="tabmodalprompt-buttonSpacer"/>
+            <xul:button class="tabmodalprompt-button0" data-l10n-id="tabmodalprompt-ok-button"/>
+            <xul:button class="tabmodalprompt-button2" hidden="true"/>
+            <xul:button class="tabmodalprompt-button1" data-l10n-id="tabmodalprompt-cancel-button"/>
+          </div>
+        </div>`
+      )
+    );
+
+    this.ui = {
+      prompt: this,
+      promptContainer: this.element,
+      mainContainer: newPrompt.querySelector(".tabmodalprompt-mainContainer"),
+      loginContainer: newPrompt.querySelector(".tabmodalprompt-loginContainer"),
+      loginTextbox: newPrompt.querySelector(".tabmodalprompt-loginTextbox"),
+      loginLabel: newPrompt.querySelector(".tabmodalprompt-loginLabel"),
+      password1Container: newPrompt.querySelector(
+        ".tabmodalprompt-password1Container"
+      ),
+      password1Textbox: newPrompt.querySelector(
+        ".tabmodalprompt-password1Textbox"
+      ),
+      password1Label: newPrompt.querySelector(".tabmodalprompt-password1Label"),
+      infoContainer: newPrompt.querySelector(".tabmodalprompt-infoContainer"),
+      infoBody: newPrompt.querySelector(".tabmodalprompt-infoBody"),
+      infoTitle: newPrompt.querySelector(".tabmodalprompt-infoTitle"),
+      infoIcon: null,
+      rows: newPrompt.querySelector(".tabmodalprompt-topContainer"),
+      checkbox: newPrompt.querySelector(".tabmodalprompt-checkbox"),
+      checkboxContainer: newPrompt.querySelector(
+        ".tabmodalprompt-checkboxContainer"
+      ),
+      button3: newPrompt.querySelector(".tabmodalprompt-button3"),
+      button2: newPrompt.querySelector(".tabmodalprompt-button2"),
+      button1: newPrompt.querySelector(".tabmodalprompt-button1"),
+      button0: newPrompt.querySelector(".tabmodalprompt-button0"),
+      // focusTarget (for BUTTON_DELAY_ENABLE) not yet supported
+    };
+
+    if (AppConstants.XP_UNIX) {
+      // Reorder buttons on Linux
+      let buttonContainer = newPrompt.querySelector(
+        ".tabmodalprompt-buttonContainer"
+      );
+      buttonContainer.appendChild(this.ui.button3);
+      buttonContainer.appendChild(this.ui.button2);
+      buttonContainer.appendChild(
+        newPrompt.querySelector(".tabmodalprompt-buttonSpacer")
+      );
+      buttonContainer.appendChild(this.ui.button1);
+      buttonContainer.appendChild(this.ui.button0);
+    }
+
+    this.ui.button0.addEventListener(
+      "command",
+      this.onButtonClick.bind(this, 0)
+    );
+    this.ui.button1.addEventListener(
+      "command",
+      this.onButtonClick.bind(this, 1)
+    );
+    this.ui.button2.addEventListener(
+      "command",
+      this.onButtonClick.bind(this, 2)
+    );
+    this.ui.button3.addEventListener(
+      "command",
+      this.onButtonClick.bind(this, 3)
+    );
+    // Anonymous wrapper used here because |Dialog| doesn't exist until init() is called!
+    this.ui.checkbox.addEventListener("command", () => {
+      this.Dialog.onCheckbox();
+    });
+
+    /**
+     * Based on dialog.xml handlers
+     */
+    this.element.addEventListener(
+      "keypress",
+      event => {
+        switch (event.keyCode) {
+          case KeyEvent.DOM_VK_RETURN:
+            this.onKeyAction("default", event);
+            break;
+
+          case KeyEvent.DOM_VK_ESCAPE:
+            this.onKeyAction("cancel", event);
+            break;
+
+          default:
+            if (
+              AppConstants.platform == "macosx" &&
+              event.key == "." &&
+              event.metaKey
+            ) {
+              this.onKeyAction("cancel", event);
+            }
+            break;
+        }
+      },
+      { mozSystemGroup: true }
+    );
+
+    this.element.addEventListener(
+      "focus",
+      event => {
+        let bnum = this.args.defaultButtonNum || 0;
+        let defaultButton = this.ui["button" + bnum];
+
+        if (AppConstants.platform == "macosx") {
+          // On OS X, the default button always stays marked as such (until
+          // the entire prompt blurs).
+          defaultButton.setAttribute("default", "true");
+        } else {
+          // On other platforms, the default button is only marked as such
+          // when no other button has focus. XUL buttons on not-OSX will
+          // react to pressing enter as a command, so you can't trigger the
+          // default without tabbing to it or something that isn't a button.
+          let focusedDefault = event.originalTarget == defaultButton;
+          let someButtonFocused =
+            event.originalTarget.localName == "button" ||
+            event.originalTarget.localName == "toolbarbutton";
+          if (focusedDefault || !someButtonFocused) {
+            defaultButton.setAttribute("default", "true");
+          }
+        }
+      },
+      true
+    );
+
+    this.element.addEventListener("blur", () => {
+      // If focus shifted to somewhere else in the browser, don't make
+      // the default button look active.
+      let bnum = this.args.defaultButtonNum || 0;
+      let button = this.ui["button" + bnum];
+      button.removeAttribute("default");
+    });
+  }
+
+  init(args, linkedTab, onCloseCallback) {
+    this.args = args;
+    this.linkedTab = linkedTab;
+    this.onCloseCallback = onCloseCallback;
+
+    if (args.enableDelay) {
+      throw new Error(
+        "BUTTON_DELAY_ENABLE not yet supported for tab-modal prompts"
+      );
+    }
+
+    // Apply styling depending on modalType (content or tab prompt)
+    if (args.modalType === Ci.nsIPrompt.MODAL_TYPE_TAB) {
+      this.element.classList.add("tab-prompt");
+    } else {
+      this.element.classList.add("content-prompt");
+    }
+
+    // We need to remove the prompt when the tab or browser window is closed or
+    // the page navigates, else we never unwind the event loop and that's sad times.
+    // Remember to cleanup in shutdownPrompt()!
+    this.win.addEventListener("resize", this);
+    this.win.addEventListener("unload", this);
+    if (linkedTab) {
+      linkedTab.addEventListener("TabClose", this);
+    }
+    // Note:
+    // nsPrompter.js or in e10s mode browser-parent.js call abortPrompt,
+    // when the domWindow, for which the prompt was created, generates
+    // a "pagehide" event.
+
+    let { CommonDialog } = ChromeUtils.importESModule(
+      "resource://gre/modules/CommonDialog.sys.mjs"
+    );
+    this.Dialog = new CommonDialog(args, this.ui);
+    this.Dialog.onLoad(null);
+
+    // For content prompts display the tabprompt title that shows the prompt origin when
+    // the prompt origin is not the same as that of the top window.
+    if (
+      args.modalType == Ci.nsIPrompt.MODAL_TYPE_CONTENT &&
+      args.showCallerOrigin
+    ) {
+      this.ui.infoTitle.removeAttribute("hidden");
+    }
+
+    // TODO: should unhide buttonSpacer on Windows when there are 4 buttons.
+    //       Better yet, just drop support for 4-button dialogs. (bug 609510)
+  }
+
+  shutdownPrompt() {
+    // remove our event listeners
+    try {
+      this.win.removeEventListener("resize", this);
+      this.win.removeEventListener("unload", this);
+      if (this.linkedTab) {
+        this.linkedTab.removeEventListener("TabClose", this);
+      }
+    } catch (e) {}
+    // invoke callback
+    this.onCloseCallback();
+    this.win = null;
+    this.ui = null;
+    // Intentionally not cleaning up |this.element| here --
+    // TabModalPromptBox.removePrompt() would need it and it might not
+    // be called yet -- see browser_double_close_tabs.js.
+  }
+
+  abortPrompt() {
+    // Called from other code when the page changes.
+    this.Dialog.abortPrompt();
+    this.shutdownPrompt();
+  }
+
+  handleEvent(aEvent) {
+    switch (aEvent.type) {
+      case "unload":
+      case "TabClose":
+        this.abortPrompt();
+        break;
+    }
+  }
+
+  onButtonClick(buttonNum) {
+    // We want to do all the work her asynchronously off a Gecko
+    // runnable, because of situations like the one described in
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1167575#c35 : we
+    // get here off processing of an OS event and will also process
+    // one more Gecko runnable before we break out of the event loop
+    // spin whoever posted the prompt is doing.  If we do all our
+    // work sync, we will exit modal state _before_ processing that
+    // runnable, and if exiting moral state posts a runnable we will
+    // incorrectly process that runnable before leaving our event
+    // loop spin.
+    Services.tm.dispatchToMainThread(() => {
+      this.Dialog["onButton" + buttonNum]();
+      this.shutdownPrompt();
+    });
+  }
+
+  onKeyAction(action, event) {
+    if (event.defaultPrevented) {
+      return;
+    }
+
+    event.stopPropagation();
+    if (action == "default") {
+      let bnum = this.args.defaultButtonNum || 0;
+      this.onButtonClick(bnum);
+    } else {
+      // action == "cancel"
+      this.onButtonClick(1); // Cancel button
+    }
+  }
+};
diff --git a/toolkit/components/prompts/docs/index.rst b/toolkit/components/prompts/docs/index.rst
new file mode 100644
index 0000000000..c518bef41b
--- /dev/null
+++ b/toolkit/components/prompts/docs/index.rst
@@ -0,0 +1,10 @@
+=======
+Prompts
+=======
+
+.. toctree::
+   :maxdepth: 1
+
+   nsIPromptService
+   nsIPromptService-reference
+   modalTypes
diff --git a/toolkit/components/prompts/docs/modal-type-content.png b/toolkit/components/prompts/docs/modal-type-content.png
new file mode 100644
index 0000000000..730fe7828c
--- /dev/null
+++ b/toolkit/components/prompts/docs/modal-type-content.png
diff --git a/toolkit/components/prompts/docs/modal-type-tab.png b/toolkit/components/prompts/docs/modal-type-tab.png
new file mode 100644
index 0000000000..66da8ef782
--- /dev/null
+++ b/toolkit/components/prompts/docs/modal-type-tab.png
diff --git a/toolkit/components/prompts/docs/modal-type-window.png b/toolkit/components/prompts/docs/modal-type-window.png
new file mode 100644
index 0000000000..505850e8de
--- /dev/null
+++ b/toolkit/components/prompts/docs/modal-type-window.png
diff --git a/toolkit/components/prompts/docs/modalTypes.rst b/toolkit/components/prompts/docs/modalTypes.rst
new file mode 100644
index 0000000000..1425d6832c
--- /dev/null
+++ b/toolkit/components/prompts/docs/modalTypes.rst
@@ -0,0 +1,95 @@
+==================
+Prompt Modal Types
+==================
+
+Window Prompts
+--------------
+
+Window prompts are system prompts. They are clearly distinguishable from website
+content and can be opened with or without a parent window.
+While a window prompt is open, the parent window cannot be interacted with.
+That means the user can not close the window or switch tabs.
+Providing a parent window is optional, but highly encouraged. If you do not
+pass a parent the implementation will try to find one or fallback to aborted
+standalone window.
+
+**When to use**: This should be reserved for important browser-wide messages
+with the intent to block any further user interaction until the message has been
+read.
+
+**Flag**: `MODAL_TYPE_WINDOW`
+
+.. caution::
+
+  When using window prompts, make sure they can not be spawned by web content.
+  We've seen `cases <https://bugzilla.mozilla.org/show_bug.cgi?id=1571003>`_
+  of DoS attacks in the wild where websites spammed window prompts to lock up
+  the browser.
+  This prompt type should only be used when necessary and with proper rate
+  limiting. Most of the time, a tab prompt can be be used.
+
+.. figure:: modal-type-window.png
+   :width: 425px
+   :height: 230px
+   :alt: Screenshot of a window prompt.
+
+   Window alert prompt
+
+Tab Prompts
+-----------
+
+Tab prompts are system prompts like window prompts. As opposed to window
+prompts, they are tab modal and don't steal focus from the parent window.
+Multiple tab prompts cannot be shown at the same time. When opening additional
+prompts, they are FIFO queued.
+
+When the user closes the tab or navigates to a different URI, prompts associated
+with the given tab are closed.
+In this case an exception will be thrown:
+
+.. code-block::
+
+    /*
+    Exception: prompt aborted by user
+    undefined:425
+    */
+
+**When to use**: This prompt should be used for dialogs that were caused by web
+content and thus should be bound to the scope and lifetime of a specific tab,
+but should still look like secure browser UI. Examples are HTTP Auth prompt or
+the dialog to add a new search provider for the current website.
+
+**Flag**: `MODAL_TYPE_TAB`
+
+
+.. figure:: modal-type-tab.png
+   :width: 425px
+   :height: 230px
+   :alt: Screenshot of a tab prompt.
+
+   Tab alert prompt
+
+Content Prompts
+---------------
+
+Content prompts are like tab prompts, but they belong to the web content. Thus,
+they are positioned in the center of the selected browser.
+
+**When to use**: The prompt is triggered by or as a result of an action of web
+content and is **not** intended to look like secure browser UI.
+
+**Flag**: `MODAL_TYPE_CONTENT`
+
+.. figure:: modal-type-content.png
+   :width: 425px
+   :height: 230px
+   :alt: Screenshot of a content prompt.
+
+   Content alert prompt
+
+
+Disabling tab/content modal prompts
+-----------------------------------
+You can disable tab and content modal prompts and get back window-modal for
+individual prompts by setting the `prompts.modalType.<promptName>` preference to
+`3`.
diff --git a/toolkit/components/prompts/docs/nsIPromptService-reference.rst b/toolkit/components/prompts/docs/nsIPromptService-reference.rst
new file mode 100644
index 0000000000..9879cd753a
--- /dev/null
+++ b/toolkit/components/prompts/docs/nsIPromptService-reference.rst
@@ -0,0 +1,10 @@
+========================
+Prompt Service Reference
+========================
+
+This is the JSDoc from the Prompter.jsm implementation. You can find the full
+interface definition in
+`nsIPromptService.idl <https://searchfox.org/mozilla-central/source/toolkit/components/windowwatcher/nsIPromptService.idl>`_.
+
+.. js:autoclass:: Prompter
+  :members:
diff --git a/toolkit/components/prompts/docs/nsIPromptService.rst b/toolkit/components/prompts/docs/nsIPromptService.rst
new file mode 100644
index 0000000000..386572ef3f
--- /dev/null
+++ b/toolkit/components/prompts/docs/nsIPromptService.rst
@@ -0,0 +1,195 @@
+==============
+Prompt Service
+==============
+
+The `nsIPromptService` provides methods for opening various types of prompts.
+See the `interface documentation <nsIPromptService-reference.html>`_ for a list
+of prompt types.
+Every prompt method has 3 different versions:
+
+- **Prompt by window**:
+  This is considered the legacy way of prompting and only works if the window
+  you want to prompt for is in the same process.
+  Only supports window prompts.
+
+- **Prompt by browsing context (synchronous)**:
+  Use a browsing context as parent for the prompt. Works cross process from
+  parent and content process.
+
+- **Prompt by browsing context (asynchronous)**:
+  Returns a promise which resolves once the prompt closes.
+
+
+The synchronous prompt methods use call by reference (XPCOM `inout` or `out`) to
+return the updated prompt arguments to the caller.
+When prompting async the arguments are passed in by value. Prompt results are
+returned in an `nsIPropertyBag` when the Promise resolves.
+
+
+.. note::
+    If you don't provide a parent window or browsing context the prompt service
+    will fallback to a window prompt.
+    The same goes for browsing contexts of chrome windows, because there is no
+    clear association to a browser / tab.
+
+
+Examples
+--------
+
+JavaScript Sync
+~~~~~~~~~~~~~~~
+
+Here is an example of opening a confirm prompt from JavaScript. We are in the
+parent process and we want to show a tab prompt:
+
+.. code-block:: javascript
+
+    // Get the browsing context for the currently selected tab
+    let browsingContext = gBrowser.selectedBrowser.browsingContext;
+
+    // Specify prompt type, can be MODAL_TYPE_TAB, MODAL_TYPE_CONTENT,
+    // MODAL_TYPE_WINDOW
+    let modalType = Services.prompt.MODAL_TYPE_TAB;
+
+    // Object for checkbox state to pass by reference.
+    let check = { value: false };
+
+    // Prompt synchronously and store result
+    let confirmed = Services.prompt.confirmCheckBC(browsingContext, modalType,
+    "My Title", "Hello, World!", "Check this box if you agree", check);
+
+    // check.value now contains final checkbox state
+    // confirmed is a boolean which indicates whether the user pressed ok (true)
+    // or cancel (false)
+    console.debug("User checked checkbox?", check.value);
+    console.debug("User confirmed prompt?", confirmed);
+
+
+JavaScript Async
+~~~~~~~~~~~~~~~~
+
+The same prompt as above, but called async:
+
+.. code-block:: javascript
+
+    // Get the browsing context for the currently selected tab
+    let browsingContext = gBrowser.selectedBrowser.browsingContext;
+
+    // Specify prompt type, can be MODAL_TYPE_TAB, MODAL_TYPE_CONTENT,
+    // MODAL_TYPE_WINDOW
+    let modalType = Services.prompt.MODAL_TYPE_TAB;
+
+    // Note that the checkbox state variable is not an object in this case,
+    because we get the checkbox result via the result object.
+    let check = false;
+
+    // Prompt asynchronously and await result
+    let propBag = await Services.prompt.asyncConfirmCheck(browsingContext,
+                                                          modalType,
+                                                          "My Title",
+                                                          "Hello, World!",
+                                                          "Check this box if you agree",
+                                                          check);
+
+    let ok = propBag.getProperty("ok");
+    let checked = propBag.getProperty("checked");
+
+    // ok is the boolean indicating if the user clicked "ok" (true) or
+    // "cancel" (false).
+    // checked is a boolean indicating the final checkbox state
+    console.debug("User checked checkbox?", checked);
+    console.debug("User confirmed prompt?", ok);
+
+
+C++ Sync
+~~~~~~~~
+
+.. code-block:: c++
+
+      nsCOMPtr<nsIPromptService> promptSvc =
+        do_GetService("@mozilla.org/prompter;1");
+
+      if(!promptSvc) {
+        // Error handling
+        return;
+      }
+
+      // Assuming you have the browsing context as a member.
+      // You might need to get the browsing context from somewhere else.
+      BrowsingContext* bc = mBrowsingContext;
+
+      bool ok;
+      bool checked = false;
+
+      nsresult rv = promptSvc->confirmCheck(mBrowsingContext,
+                                            nsIPromptService::MODAL_TYPE_TAB,
+                                            "My Title"_ns
+                                            "Hello, World!"_ns,
+                                            "Check this box if you agree"_ns,
+                                            &checked, &ok);
+
+      // ok is the boolean indicating if the user clicked "ok" (true) or
+      // "cancel" (false).
+      // checked is a boolean indicating the final checkbox state
+
+C++ Async
+~~~~~~~~~
+
+.. code-block:: c++
+
+      nsCOMPtr<nsIPromptService> promptSvc =
+        do_GetService("@mozilla.org/prompter;1");
+
+      if(!promptSvc) {
+        // Error handling
+        return;
+      }
+
+      bool checked = false;
+      Promise* promise;
+
+      // Assuming you have the browsing context as a member.
+      // You might need to get the browsing context from somewhere else.
+      BrowsingContext* bc = mBrowsingContext;
+
+      // As opposed to the sync case, here we pass the checked flag by value
+      nsresult rv = promptSvc->confirmCheckAsync(mBrowsingContext,
+                                                 nsIPromptService::MODAL_TYPE_TAB, "My Title"_ns,
+                                                 "Hello, World!"_ns,
+                                                 "Check this box if you agree"_ns,
+                                                 checked, promise);
+
+      // Attach a promise handler
+      RefPtr<PromptHandler> handler = new PromptHandler(promise);
+      promise->AppendNativeHandler(handler);
+
+Then, in your promise handler callback function:
+
+.. code-block:: c++
+
+      void PromptHandler::ResolvedCallback(JSContext* aCx,
+                                       JS::Handle<JS::Value> aValue) {
+        JS::Rooted<JSObject*> detailObj(aCx, &aValue.toObject());
+
+        // Convert the JSObject back to a property bag
+        nsresult rv;
+        nsCOMPtr<nsIPropertyBag2> propBag;
+        rv = UnwrapArg<nsIPropertyBag2>(aCx, detailObj, getter_AddRefs(propBag));
+        if (NS_FAILED(rv)) return;
+
+        bool ok;
+        bool checked;
+        propBag->GetPropertyAsBool(u"ok"_ns, &ok);
+        propBag->GetPropertyAsBool(u"checked"_ns, &checked);
+
+        // ok is the boolean indicating if the user clicked "ok" (true) or
+        // "cancel" (false).
+        // checked is a boolean indicating the final checkbox state.
+      }
+
+
+
+
+
+For a full list of prompt methods check
+`nsIPromptService reference <nsIPromptService-reference.html>`_.
diff --git a/toolkit/components/prompts/jar.mn b/toolkit/components/prompts/jar.mn
new file mode 100644
index 0000000000..819af6dc1d
--- /dev/null
+++ b/toolkit/components/prompts/jar.mn
@@ -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/.
+
+toolkit.jar:
+   content/global/adjustableTitle.js          (content/adjustableTitle.js)
+   content/global/commonDialog.js             (content/commonDialog.js)
+   content/global/commonDialog.xhtml          (content/commonDialog.xhtml)
+   content/global/commonDialog.css            (content/commonDialog.css)
+   content/global/selectDialog.js             (content/selectDialog.js)
+   content/global/selectDialog.xhtml          (content/selectDialog.xhtml)
+   content/global/tabprompts.css              (content/tabprompts.css)
+   content/global/tabprompts.sys.mjs          (content/tabprompts.sys.mjs)
diff --git a/toolkit/components/prompts/moz.build b/toolkit/components/prompts/moz.build
new file mode 100644
index 0000000000..64a3115cbe
--- /dev/null
+++ b/toolkit/components/prompts/moz.build
@@ -0,0 +1,24 @@
+# -*- 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/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Notifications and Alerts")
+
+DIRS += ["src"]
+
+SPHINX_TREES["prompts"] = "docs"
+
+with Files("docs/**"):
+    SCHEDULES.exclusive = ["docs"]
+
+TESTING_JS_MODULES += [
+    "test/PromptTestUtils.sys.mjs",
+]
+
+MOCHITEST_MANIFESTS += ["test/mochitest.ini"]
+MOCHITEST_CHROME_MANIFESTS += ["test/chrome.ini"]
+
+JAR_MANIFESTS += ["jar.mn"]
diff --git a/toolkit/components/prompts/src/CommonDialog.sys.mjs b/toolkit/components/prompts/src/CommonDialog.sys.mjs
new file mode 100644
index 0000000000..a0812aa8ec
--- /dev/null
+++ b/toolkit/components/prompts/src/CommonDialog.sys.mjs
@@ -0,0 +1,381 @@
+/* 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, {
+  EnableDelayHelper: "resource://gre/modules/PromptUtils.sys.mjs",
+});
+
+import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
+
+export function CommonDialog(args, ui) {
+  this.args = args;
+  this.ui = ui;
+  this.initialFocusPromise = new Promise(resolve => {
+    this.initialFocusResolver = resolve;
+  });
+}
+
+CommonDialog.prototype = {
+  args: null,
+  ui: null,
+
+  hasInputField: true,
+  numButtons: undefined,
+  iconClass: undefined,
+  soundID: undefined,
+  focusTimer: null,
+  initialFocusPromise: null,
+  initialFocusResolver: null,
+
+  /**
+   * @param [commonDialogEl] - Dialog element from commonDialog.xhtml,
+   * null for TabModalPrompts.
+   */
+  async onLoad(commonDialogEl = null) {
+    let isEmbedded = !!commonDialogEl?.ownerGlobal.docShell.chromeEventHandler;
+
+    switch (this.args.promptType) {
+      case "alert":
+      case "alertCheck":
+        this.hasInputField = false;
+        this.numButtons = 1;
+        this.iconClass = ["alert-icon"];
+        this.soundID = Ci.nsISound.EVENT_ALERT_DIALOG_OPEN;
+        break;
+      case "confirmCheck":
+      case "confirm":
+        this.hasInputField = false;
+        this.numButtons = 2;
+        this.iconClass = ["question-icon"];
+        this.soundID = Ci.nsISound.EVENT_CONFIRM_DIALOG_OPEN;
+        break;
+      case "confirmEx":
+        var numButtons = 0;
+        if (this.args.button0Label) {
+          numButtons++;
+        }
+        if (this.args.button1Label) {
+          numButtons++;
+        }
+        if (this.args.button2Label) {
+          numButtons++;
+        }
+        if (this.args.button3Label) {
+          numButtons++;
+        }
+        if (numButtons == 0) {
+          throw new Error("A dialog with no buttons? Can not haz.");
+        }
+        this.numButtons = numButtons;
+        this.hasInputField = false;
+        this.iconClass = ["question-icon"];
+        this.soundID = Ci.nsISound.EVENT_CONFIRM_DIALOG_OPEN;
+        break;
+      case "prompt":
+        this.numButtons = 2;
+        this.iconClass = ["question-icon"];
+        this.soundID = Ci.nsISound.EVENT_PROMPT_DIALOG_OPEN;
+        this.initTextbox("login", this.args.value);
+        // Clear the label, since this isn't really a username prompt.
+        this.ui.loginLabel.setAttribute("value", "");
+        // Ensure the labeling for the prompt is correct.
+        this.ui.loginTextbox.setAttribute("aria-labelledby", "infoBody");
+        break;
+      case "promptUserAndPass":
+        this.numButtons = 2;
+        this.iconClass = ["authentication-icon", "question-icon"];
+        this.soundID = Ci.nsISound.EVENT_PROMPT_DIALOG_OPEN;
+        this.initTextbox("login", this.args.user);
+        this.initTextbox("password1", this.args.pass);
+        break;
+      case "promptPassword":
+        this.numButtons = 2;
+        this.iconClass = ["authentication-icon", "question-icon"];
+        this.soundID = Ci.nsISound.EVENT_PROMPT_DIALOG_OPEN;
+        this.initTextbox("password1", this.args.pass);
+        // Clear the label, since the message presumably indicates its purpose.
+        this.ui.password1Label.setAttribute("value", "");
+        break;
+      default:
+        console.error(
+          "commonDialog opened for unknown type: ",
+          this.args.promptType
+        );
+        throw new Error("unknown dialog type");
+    }
+
+    if (commonDialogEl) {
+      commonDialogEl.setAttribute(
+        "windowtype",
+        "prompt:" + this.args.promptType
+      );
+    }
+
+    // set the document title
+    let title = this.args.title;
+    let infoTitle = this.ui.infoTitle;
+    infoTitle.appendChild(infoTitle.ownerDocument.createTextNode(title));
+
+    // Specific check to prevent showing the title on the old content prompts for macOS.
+    // This should be removed when the old content prompts are removed.
+    let contentSubDialogPromptEnabled = Services.prefs.getBoolPref(
+      "prompts.contentPromptSubDialog"
+    );
+    let isOldContentPrompt =
+      !contentSubDialogPromptEnabled &&
+      this.args.modalType == Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+    // After making these preventative checks, we can determine to show it if we're on
+    // macOS (where there is no titlebar) or if the prompt is a common dialog document
+    // and has been embedded (has a chromeEventHandler).
+    infoTitle.hidden =
+      isOldContentPrompt || !(AppConstants.platform === "macosx" || isEmbedded);
+
+    if (commonDialogEl) {
+      commonDialogEl.ownerDocument.title = title;
+    }
+
+    // Set button labels and visibility
+    //
+    // This assumes that button0 defaults to a visible "ok" button, and
+    // button1 defaults to a visible "cancel" button. The other 2 buttons
+    // have no default labels (and are hidden).
+    switch (this.numButtons) {
+      case 4:
+        this.setLabelForNode(this.ui.button3, this.args.button3Label);
+        this.ui.button3.hidden = false;
+      // fall through
+      case 3:
+        this.setLabelForNode(this.ui.button2, this.args.button2Label);
+        this.ui.button2.hidden = false;
+      // fall through
+      case 2:
+        // Defaults to a visible "cancel" button
+        if (this.args.button1Label) {
+          this.setLabelForNode(this.ui.button1, this.args.button1Label);
+        }
+        break;
+
+      case 1:
+        this.ui.button1.hidden = true;
+        break;
+    }
+    // Defaults to a visible "ok" button
+    if (this.args.button0Label) {
+      this.setLabelForNode(this.ui.button0, this.args.button0Label);
+    }
+
+    // display the main text
+    let croppedMessage = "";
+    if (this.args.text) {
+      // Bug 317334 - crop string length as a workaround.
+      croppedMessage = this.args.text.substr(0, 10000);
+      // TabModalPrompts don't have an infoRow to hide / not hide here, so
+      // guard on that here so long as they are in use.
+      if (this.ui.infoRow) {
+        this.ui.infoRow.hidden = false;
+      }
+    }
+    let infoBody = this.ui.infoBody;
+    infoBody.appendChild(infoBody.ownerDocument.createTextNode(croppedMessage));
+
+    let label = this.args.checkLabel;
+    if (label) {
+      // Only show the checkbox if label has a value.
+      this.ui.checkboxContainer.hidden = false;
+      this.ui.checkboxContainer.clientTop; // style flush to assure binding is attached
+      this.setLabelForNode(this.ui.checkbox, label);
+      this.ui.checkbox.checked = this.args.checked;
+    }
+
+    // set the icon
+    let icon = this.ui.infoIcon;
+    if (icon) {
+      this.iconClass.forEach((el, idx, arr) => icon.classList.add(el));
+    }
+
+    // set default result to cancelled
+    this.args.ok = false;
+    this.args.buttonNumClicked = 1;
+
+    // Set the default button
+    let b = this.args.defaultButtonNum || 0;
+    let button = this.ui["button" + b];
+
+    if (commonDialogEl) {
+      commonDialogEl.defaultButton = ["accept", "cancel", "extra1", "extra2"][
+        b
+      ];
+    } else {
+      button.setAttribute("default", "true");
+    }
+
+    if (!isEmbedded && !this.ui.promptContainer?.hidden) {
+      // Set default focus and select textbox contents if applicable. If we're
+      // embedded SubDialogManager will call setDefaultFocus for us.
+      this.setDefaultFocus(true);
+    }
+
+    if (this.args.enableDelay) {
+      this.delayHelper = new lazy.EnableDelayHelper({
+        disableDialog: () => this.setButtonsEnabledState(false),
+        enableDialog: () => this.setButtonsEnabledState(true),
+        focusTarget: this.ui.focusTarget,
+      });
+    }
+
+    // Play a sound (unless we're showing a content prompt -- don't want those
+    //               to feel like OS prompts).
+    try {
+      if (commonDialogEl && this.soundID && !this.args.openedWithTabDialog) {
+        Cc["@mozilla.org/sound;1"]
+          .getService(Ci.nsISound)
+          .playEventSound(this.soundID);
+      }
+    } catch (e) {
+      console.error("Couldn't play common dialog event sound: ", e);
+    }
+
+    if (commonDialogEl) {
+      if (isEmbedded) {
+        // If we delayed default focus above, wait for it to be ready before
+        // sending the notification.
+        await this.initialFocusPromise;
+      }
+      Services.obs.notifyObservers(this.ui.prompt, "common-dialog-loaded");
+    } else {
+      // ui.promptContainer is the <tabmodalprompt> element.
+      Services.obs.notifyObservers(
+        this.ui.promptContainer,
+        "tabmodal-dialog-loaded"
+      );
+    }
+  },
+
+  setLabelForNode(aNode, aLabel) {
+    // This is for labels which may contain embedded access keys.
+    // If we end in (&X) where X represents the access key, optionally preceded
+    // by spaces and/or followed by the ':' character, store the access key and
+    // remove the access key placeholder + leading spaces from the label.
+    // Otherwise a character preceded by one but not two &s is the access key.
+    // Store it and remove the &.
+
+    // Note that if you change the following code, see the comment of
+    // nsTextBoxFrame::UpdateAccessTitle.
+    var accessKey = null;
+    if (/ *\(\&([^&])\)(:?)$/.test(aLabel)) {
+      aLabel = RegExp.leftContext + RegExp.$2;
+      accessKey = RegExp.$1;
+    } else if (/^([^&]*)\&(([^&]).*$)/.test(aLabel)) {
+      aLabel = RegExp.$1 + RegExp.$2;
+      accessKey = RegExp.$3;
+    }
+
+    // && is the magic sequence to embed an & in your label.
+    aLabel = aLabel.replace(/\&\&/g, "&");
+    aNode.label = aLabel;
+
+    // XXXjag bug 325251
+    // Need to set this after aNode.setAttribute("value", aLabel);
+    if (accessKey) {
+      aNode.accessKey = accessKey;
+    }
+  },
+
+  initTextbox(aName, aValue) {
+    this.ui[aName + "Container"].hidden = false;
+    this.ui[aName + "Textbox"].setAttribute(
+      "value",
+      aValue !== null ? aValue : ""
+    );
+  },
+
+  setButtonsEnabledState(enabled) {
+    this.ui.button0.disabled = !enabled;
+    // button1 (cancel) remains enabled.
+    this.ui.button2.disabled = !enabled;
+    this.ui.button3.disabled = !enabled;
+  },
+
+  setDefaultFocus(isInitialLoad) {
+    let b = this.args.defaultButtonNum || 0;
+    let button = this.ui["button" + b];
+
+    if (!this.hasInputField) {
+      let isOSX = "nsILocalFileMac" in Ci;
+      // If the infoRow exists and is is hidden, then the infoBody is also hidden,
+      // which means it can't be focused. At that point, we fall back to focusing
+      // the default button, regardless of platform.
+      if (isOSX && !(this.ui.infoRow && this.ui.infoRow.hidden)) {
+        this.ui.infoBody.focus();
+      } else {
+        button.focus({ focusVisible: false });
+      }
+    } else if (this.args.promptType == "promptPassword") {
+      // When the prompt is initialized, focus and select the textbox
+      // contents. Afterwards, only focus the textbox.
+      if (isInitialLoad) {
+        this.ui.password1Textbox.select();
+      } else {
+        this.ui.password1Textbox.focus();
+      }
+    } else if (isInitialLoad) {
+      this.ui.loginTextbox.select();
+    } else {
+      this.ui.loginTextbox.focus();
+    }
+
+    if (isInitialLoad) {
+      this.initialFocusResolver();
+    }
+  },
+
+  onCheckbox() {
+    this.args.checked = this.ui.checkbox.checked;
+  },
+
+  onButton0() {
+    this.args.promptActive = false;
+    this.args.ok = true;
+    this.args.buttonNumClicked = 0;
+
+    let username = this.ui.loginTextbox.value;
+    let password = this.ui.password1Textbox.value;
+
+    // Return textfield values
+    switch (this.args.promptType) {
+      case "prompt":
+        this.args.value = username;
+        break;
+      case "promptUserAndPass":
+        this.args.user = username;
+        this.args.pass = password;
+        break;
+      case "promptPassword":
+        this.args.pass = password;
+        break;
+    }
+  },
+
+  onButton1() {
+    this.args.promptActive = false;
+    this.args.buttonNumClicked = 1;
+  },
+
+  onButton2() {
+    this.args.promptActive = false;
+    this.args.buttonNumClicked = 2;
+  },
+
+  onButton3() {
+    this.args.promptActive = false;
+    this.args.buttonNumClicked = 3;
+  },
+
+  abortPrompt() {
+    this.args.promptActive = false;
+    this.args.promptAborted = true;
+  },
+};
diff --git a/toolkit/components/prompts/src/PromptUtils.sys.mjs b/toolkit/components/prompts/src/PromptUtils.sys.mjs
new file mode 100644
index 0000000000..7a15802b84
--- /dev/null
+++ b/toolkit/components/prompts/src/PromptUtils.sys.mjs
@@ -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/. */
+
+export var PromptUtils = {
+  // Fire a dialog open/close event. Used by tabbrowser to focus the
+  // tab which is triggering a prompt.
+  // For remote dialogs, we pass in a different DOM window and a separate
+  // target. If the caller doesn't pass in the target, then we'll simply use
+  // the passed-in DOM window.
+  // The detail may contain information about the principal on which the
+  // prompt is triggered, as well as whether or not this is a tabprompt
+  // (ie tabmodal alert/prompt/confirm and friends)
+  fireDialogEvent(domWin, eventName, maybeTarget, detail) {
+    let target = maybeTarget || domWin;
+    let eventOptions = { cancelable: true, bubbles: true };
+    if (detail) {
+      eventOptions.detail = detail;
+    }
+    let event = new domWin.CustomEvent(eventName, eventOptions);
+    let winUtils = domWin.windowUtils;
+    winUtils.dispatchEventToChromeOnly(target, event);
+  },
+
+  objectToPropBag(obj) {
+    let bag = Cc["@mozilla.org/hash-property-bag;1"].createInstance(
+      Ci.nsIWritablePropertyBag2
+    );
+    bag.QueryInterface(Ci.nsIWritablePropertyBag);
+
+    for (let propName in obj) {
+      bag.setProperty(propName, obj[propName]);
+    }
+
+    return bag;
+  },
+
+  propBagToObject(propBag, obj) {
+    // Here we iterate over the object's original properties, not the bag
+    // (ie, the prompt can't return more/different properties than were
+    // passed in). This just helps ensure that the caller provides default
+    // values, lest the prompt forget to set them.
+    for (let propName in obj) {
+      obj[propName] = propBag.getProperty(propName);
+    }
+  },
+};
+
+/**
+ * This helper handles the enabling/disabling of dialogs that might
+ * be subject to fast-clicking attacks. It handles the initial delayed
+ * enabling of the dialog, as well as disabling it on blur and reapplying
+ * the delay when the dialog regains focus.
+ *
+ * @param enableDialog   A custom function to be called when the dialog
+ *                       is to be enabled.
+ * @param diableDialog   A custom function to be called when the dialog
+ *                       is to be disabled.
+ * @param focusTarget    The window used to watch focus/blur events.
+ */
+export var EnableDelayHelper = function ({
+  enableDialog,
+  disableDialog,
+  focusTarget,
+}) {
+  this.enableDialog = makeSafe(enableDialog);
+  this.disableDialog = makeSafe(disableDialog);
+  this.focusTarget = focusTarget;
+
+  this.disableDialog();
+
+  this.focusTarget.addEventListener("blur", this);
+  this.focusTarget.addEventListener("focus", this);
+  // While the user key-repeats, we want to renew the timer until keyup:
+  this.focusTarget.addEventListener("keyup", this, true);
+  this.focusTarget.addEventListener("keydown", this, true);
+  this.focusTarget.document.addEventListener("unload", this);
+
+  this.startOnFocusDelay();
+};
+
+EnableDelayHelper.prototype = {
+  get delayTime() {
+    return Services.prefs.getIntPref("security.dialog_enable_delay");
+  },
+
+  handleEvent(event) {
+    if (
+      !event.type.startsWith("key") &&
+      event.target != this.focusTarget &&
+      event.target != this.focusTarget.document
+    ) {
+      return;
+    }
+
+    switch (event.type) {
+      case "keyup":
+        // As soon as any key goes up, we can stop treating keypresses
+        // as indicative of key-repeating that should prolong the timer.
+        this.focusTarget.removeEventListener("keyup", this, true);
+        this.focusTarget.removeEventListener("keydown", this, true);
+        break;
+
+      case "keydown":
+        // Renew timer for repeating keydowns:
+        if (this._focusTimer) {
+          this._focusTimer.cancel();
+          this._focusTimer = null;
+          this.startOnFocusDelay();
+          event.preventDefault();
+        }
+        break;
+
+      case "blur":
+        this.onBlur();
+        break;
+
+      case "focus":
+        this.onFocus();
+        break;
+
+      case "unload":
+        this.onUnload();
+        break;
+    }
+  },
+
+  onBlur() {
+    this.disableDialog();
+    // If we blur while waiting to enable the buttons, just cancel the
+    // timer to ensure the delay doesn't fire while not focused.
+    if (this._focusTimer) {
+      this._focusTimer.cancel();
+      this._focusTimer = null;
+    }
+  },
+
+  onFocus() {
+    this.startOnFocusDelay();
+  },
+
+  onUnload() {
+    this.focusTarget.removeEventListener("blur", this);
+    this.focusTarget.removeEventListener("focus", this);
+    this.focusTarget.removeEventListener("keyup", this, true);
+    this.focusTarget.removeEventListener("keydown", this, true);
+    this.focusTarget.document.removeEventListener("unload", this);
+
+    if (this._focusTimer) {
+      this._focusTimer.cancel();
+      this._focusTimer = null;
+    }
+
+    this.focusTarget = this.enableDialog = this.disableDialog = null;
+  },
+
+  startOnFocusDelay() {
+    if (this._focusTimer) {
+      return;
+    }
+
+    this._focusTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+    this._focusTimer.initWithCallback(
+      () => {
+        this.onFocusTimeout();
+      },
+      this.delayTime,
+      Ci.nsITimer.TYPE_ONE_SHOT
+    );
+  },
+
+  onFocusTimeout() {
+    this._focusTimer = null;
+    this.enableDialog();
+  },
+};
+
+function makeSafe(fn) {
+  return function () {
+    // The dialog could be gone by now (if the user closed it),
+    // which makes it likely that the given fn might throw.
+    try {
+      fn();
+    } catch (e) {}
+  };
+}
diff --git a/toolkit/components/prompts/src/Prompter.sys.mjs b/toolkit/components/prompts/src/Prompter.sys.mjs
new file mode 100644
index 0000000000..fe44992378
--- /dev/null
+++ b/toolkit/components/prompts/src/Prompter.sys.mjs
@@ -0,0 +1,1824 @@
+/* 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 { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+// This is redefined below, for strange and unfortunate reasons.
+import { PromptUtils } from "resource://gre/modules/PromptUtils.sys.mjs";
+
+const {
+  MODAL_TYPE_TAB,
+  MODAL_TYPE_CONTENT,
+  MODAL_TYPE_WINDOW,
+  MODAL_TYPE_INTERNAL_WINDOW,
+} = Ci.nsIPrompt;
+
+const COMMON_DIALOG = "chrome://global/content/commonDialog.xhtml";
+const SELECT_DIALOG = "chrome://global/content/selectDialog.xhtml";
+
+export function Prompter() {
+  // Note that EmbedPrompter clones this implementation.
+}
+
+/**
+ * Implements nsIPromptService and nsIPromptFactory
+ * @class Prompter
+ */
+Prompter.prototype = {
+  classID: Components.ID("{1c978d25-b37f-43a8-a2d6-0c7a239ead87}"),
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIPromptFactory",
+    "nsIPromptService",
+  ]),
+
+  /* ----------  private members  ---------- */
+
+  pickPrompter(options) {
+    return new ModalPrompter(options);
+  },
+
+  /* ----------  nsIPromptFactory  ---------- */
+
+  getPrompt(domWin, iid) {
+    // This is still kind of dumb; the C++ code delegated to login manager
+    // here, which in turn calls back into us via nsIPromptService.
+    if (iid.equals(Ci.nsIAuthPrompt2) || iid.equals(Ci.nsIAuthPrompt)) {
+      try {
+        let pwmgr = Cc[
+          "@mozilla.org/passwordmanager/authpromptfactory;1"
+        ].getService(Ci.nsIPromptFactory);
+        return pwmgr.getPrompt(domWin, iid);
+      } catch (e) {
+        console.error("nsPrompter: Delegation to password manager failed: ", e);
+      }
+    }
+
+    let p = new ModalPrompter({ domWin });
+    p.QueryInterface(iid);
+    return p;
+  },
+
+  /* ----------  nsIPromptService  ---------- */
+
+  /**
+   * Puts up an alert dialog with an OK button.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   */
+  alert(domWin, title, text) {
+    let p = this.pickPrompter({ domWin });
+    p.alert(title, text);
+  },
+
+  /**
+   * Puts up an alert dialog with an OK button.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   */
+  alertBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    p.alert(...promptArgs);
+  },
+
+  /**
+   * Puts up an alert dialog with an OK button.
+   *
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @returns {Promise} A promise which resolves when the prompt is dismissed.
+   */
+  asyncAlert(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.alert(...promptArgs);
+  },
+
+  /**
+   * Puts up an alert dialog with an OK button and a labeled checkbox.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   */
+  alertCheck(domWin, title, text, checkLabel, checkValue) {
+    let p = this.pickPrompter({ domWin });
+    p.alertCheck(title, text, checkLabel, checkValue);
+  },
+
+  /**
+   * Puts up an alert dialog with an OK button and a labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   */
+  alertCheckBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    p.alertCheck(...promptArgs);
+  },
+
+  /**
+   * Puts up an alert dialog with an OK button and a labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Boolean} checkValue - The initial checked state of the checkbox.
+   * @returns {Promise<nsIPropertyBag<{ checked: Boolean }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncAlertCheck(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.alertCheck(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  confirm(domWin, title, text) {
+    let p = this.pickPrompter({ domWin });
+    return p.confirm(title, text);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  confirmBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.confirm(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncConfirm(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.confirm(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons and a labeled checkbox.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   */
+  confirmCheck(domWin, title, text, checkLabel, checkValue) {
+    let p = this.pickPrompter({ domWin });
+    return p.confirmCheck(title, text, checkLabel, checkValue);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons and a labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   * @returns {Boolean} true for OK, false for Cancel
+   */
+  confirmCheckBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.confirmCheck(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with OK and Cancel buttons and a labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   * @param {Boolean} checkValue - The initial checked state of the checkbox.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean, checked: Boolean }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncConfirmCheck(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.confirmCheck(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with up to 3 buttons and an optional, labeled checkbox.
+   *
+   * Buttons are numbered 0 - 2. Button 0 is the default button unless one of
+   * the Button Default Flags is specified.
+   *
+   * A button may use a predefined title, specified by one of the Button Title
+   * Flags values.  Each title value can be multiplied by a position value to
+   * assign the title to a particular button.  If BUTTON_TITLE_IS_STRING is
+   * used for a button, the string parameter for that button will be used.  If
+   * the value for a button position is zero, the button will not be shown.
+   *
+   * In general, flags is constructed per the following example:
+   *
+   * flags = (BUTTON_POS_0) * (BUTTON_TITLE_AAA) +
+   *         (BUTTON_POS_1) * (BUTTON_TITLE_BBB) +
+   *         BUTTON_POS_1_DEFAULT;
+   *
+   * where "AAA" and "BBB" correspond to one of the button titles.
+   *
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Number} flags - A combination of Button Flags.
+   * @param {String} button0 - Used when button 0 uses TITLE_IS_STRING.
+   * @param {String} button1 - Used when button 1 uses TITLE_IS_STRING.
+   * @param {String} button2 - Used when button 2 uses TITLE_IS_STRING.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        Null if no checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method
+   *        is called and the final checked state after this method returns.
+   * @returns {Number} The index of the button pressed.
+   */
+  confirmEx(
+    domWin,
+    title,
+    text,
+    flags,
+    button0,
+    button1,
+    button2,
+    checkLabel,
+    checkValue
+  ) {
+    let p = this.pickPrompter({ domWin });
+    return p.confirmEx(
+      title,
+      text,
+      flags,
+      button0,
+      button1,
+      button2,
+      checkLabel,
+      checkValue
+    );
+  },
+
+  /**
+   * Puts up a dialog with up to 3 buttons and an optional, labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Number} flags - A combination of Button Flags.
+   * @param {String} button0 - Used when button 0 uses TITLE_IS_STRING.
+   * @param {String} button1 - Used when button 1 uses TITLE_IS_STRING.
+   * @param {String} button2 - Used when button 2 uses TITLE_IS_STRING.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        Null if no checkbox.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   * @returns {Number} The index of the button pressed.
+   */
+  confirmExBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.confirmEx(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with up to 3 buttons and an optional, labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Number} flags - A combination of Button Flags.
+   * @param {String} button0 - Used when button 0 uses TITLE_IS_STRING.
+   * @param {String} button1 - Used when button 1 uses TITLE_IS_STRING.
+   * @param {String} button2 - Used when button 2 uses TITLE_IS_STRING.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        Null if no checkbox.
+   * @param {Boolean} checkValue - The initial checked state of the checkbox.
+   * @param {Object} [extraArgs] - Extra arguments for the prompt metadata.
+   * @returns {Promise<nsIPropertyBag<{ buttonNumClicked: Number, checked: Boolean }>>}
+   */
+  asyncConfirmEx(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.confirmEx(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and an optional, labeled checkbox.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} value - Contains the default value for the dialog field
+   *        when this method is called (null value is ok).  Upon return, if
+   *        the user pressed OK, then this parameter contains a newly
+   *        allocated string value.
+   *        Otherwise, the parameter's value is unmodified.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        If null, check box will not be shown.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  prompt(domWin, title, text, value, checkLabel, checkValue) {
+    let p = this.pickPrompter({ domWin });
+    return p.nsIPrompt_prompt(title, text, value, checkLabel, checkValue);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and an optional, labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} value - Contains the default value for the dialog field
+   *        when this method is called (null value is ok).  Upon return, if
+   *        the user pressed OK, then this parameter contains a newly
+   *        allocated string value.
+   *        Otherwise, the parameter's value is unmodified.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        If null, check box will not be shown.
+   * @param {Object} checkValue - Contains the initial checked state of the
+   *        checkbox when this method is called and the final checked state
+   *        after this method returns.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  promptBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.nsIPrompt_prompt(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and an optional, labeled checkbox.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} value - The default value for the dialog text field.
+   * @param {String} checkLabel - Text to appear with the checkbox.
+   *        If null, check box will not be shown.
+   * @param {Boolean} checkValue - The initial checked state of the checkbox.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean, checked: Boolean, value: String }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncPrompt(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.nsIPrompt_prompt(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and a password field.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} user - Contains the default value for the username
+   *        field when this method is called (null value is ok).
+   *        Upon return, if the user pressed OK, then this parameter contains
+   *        a newly allocated string value. Otherwise, the parameter's value
+   *        is unmodified.
+   * @param {Object} pass - Contains the default value for the password field
+   *        when this method is called (null value is ok). Upon return, if the
+   *        user pressed OK, this parameter contains a newly allocated string
+   *        value. Otherwise, the parameter's value is unmodified.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  promptUsernameAndPassword(domWin, title, text, user, pass) {
+    let p = this.pickPrompter({ domWin });
+    return p.nsIPrompt_promptUsernameAndPassword(null, title, text, user, pass);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and a password field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} user - Contains the default value for the username
+   *        field when this method is called (null value is ok).
+   *        Upon return, if the user pressed OK, then this parameter contains
+   *        a newly allocated string value. Otherwise, the parameter's value
+   *        is unmodified.
+   * @param {Object} pass - Contains the default value for the password field
+   *        when this method is called (null value is ok). Upon return, if the
+   *        user pressed OK, this parameter contains a newly allocated string
+   *        value. Otherwise, the parameter's value is unmodified.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  promptUsernameAndPasswordBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.nsIPrompt_promptUsernameAndPassword(null, ...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with an edit field and a password field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} user - Default value for the username field.
+   * @param {String} pass - Contains the default value for the password field.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean, user: String, pass: String }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncPromptUsernameAndPassword(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.nsIPrompt_promptUsernameAndPassword(null, ...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with a password field.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} pass - Contains the default value for the password field
+   *        when this method is called (null value is ok). Upon return, if the
+   *        user pressed OK, this parameter contains a newly allocated string
+   *        value. Otherwise, the parameter's value is unmodified.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  promptPassword(domWin, title, text, pass) {
+    let p = this.pickPrompter({ domWin });
+    return p.nsIPrompt_promptPassword(
+      null, // no channel.
+      title,
+      text,
+      pass
+    );
+  },
+
+  /**
+   * Puts up a dialog with a password field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {Object} pass - Contains the default value for the password field
+   *        when this method is called (null value is ok). Upon return, if the
+   *        user pressed OK, this parameter contains a newly allocated string
+   *        value. Otherwise, the parameter's value is unmodified.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  promptPasswordBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.nsIPrompt_promptPassword(null, ...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog with a password field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String} pass - Contains the default value for the password field.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean, pass: String }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncPromptPassword(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.nsIPrompt_promptPassword(null, ...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog box which has a list box of strings from which the user
+   * may make a single selection.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String[]} list - The list of strings to display.
+   * @param {Object} selected - Contains the index of the selected item in the
+   *        list when this method returns true.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  select(domWin, title, text, list, selected) {
+    let p = this.pickPrompter({ domWin });
+    return p.select(title, text, list, selected);
+  },
+
+  /**
+   * Puts up a dialog box which has a list box of strings from which the user
+   * may make a single selection.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String[]} list - The list of strings to display.
+   * @param {Object} selected - Contains the index of the selected item in the
+   *        list when this method returns true.
+   * @returns {Boolean} true for OK, false for Cancel.
+   */
+  selectBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.select(...promptArgs);
+  },
+
+  /**
+   * Puts up a dialog box which has a list box of strings from which the user
+   * may make a single selection.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} title - Text to appear in the title of the dialog.
+   * @param {String} text - Text to appear in the body of the dialog.
+   * @param {String[]} list - The list of strings to display.
+   * @returns {Promise<nsIPropertyBag<{ selected: Number, ok: Boolean  }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncSelect(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.select(...promptArgs);
+  },
+
+  /**
+   * Requests a username and a password. Shows a dialog with username and
+   * password field, depending on flags also a domain field.
+   * @param {mozIDOMWindowProxy} domWin - The parent window or null.
+   * @param {nsIChannel} channel - The channel that requires authentication.
+   * @param {Number} level - Security level of the credential transmission.
+   *        Any of nsIAuthPrompt2.<LEVEL_NONE|LEVEL_PW_ENCRYPTED|LEVEL_SECURE>
+   * @param {nsIAuthInformation} authInfo - Authentication information object.
+   * @returns {Boolean}
+   *          true: Authentication can proceed using the values
+   *          in the authInfo object.
+   *          false: Authentication should be cancelled, usually because the
+   *          user did not provide username/password.
+   */
+  promptAuth(domWin, channel, level, authInfo) {
+    let p = this.pickPrompter({ domWin });
+    return p.promptAuth(channel, level, authInfo);
+  },
+
+  /**
+   * Requests a username and a password. Shows a dialog with username and
+   * password field, depending on flags also a domain field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {nsIChannel} channel - The channel that requires authentication.
+   * @param {Number} level - Security level of the credential transmission.
+   *        Any of nsIAuthPrompt2.<LEVEL_NONE|LEVEL_PW_ENCRYPTED|LEVEL_SECURE>
+   * @param {nsIAuthInformation} authInfo - Authentication information object.
+   * @returns {Boolean}
+   *          true: Authentication can proceed using the values
+   *          in the authInfo object.
+   *          false: Authentication should be cancelled, usually because the
+   *          user did not provide username/password.
+   */
+  promptAuthBC(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType });
+    return p.promptAuth(...promptArgs);
+  },
+
+  /**
+   * Requests a username and a password. Shows a dialog with username and
+   * password field, depending on flags also a domain field.
+   * @param {BrowsingContext} browsingContext - The browsing context the
+   *        prompt should be opened for.
+   * @param {Number} modalType - The modal type of the prompt.
+   *        nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {nsIChannel} channel - The channel that requires authentication.
+   * @param {Number} level - Security level of the credential transmission.
+   *        Any of nsIAuthPrompt2.<LEVEL_NONE|LEVEL_PW_ENCRYPTED|LEVEL_SECURE>
+   * @param {nsIAuthInformation} authInfo - Authentication information object.
+   * @returns {Promise<nsIPropertyBag<{ ok: Boolean }>>}
+   *          A promise which resolves when the prompt is dismissed.
+   */
+  asyncPromptAuth(browsingContext, modalType, ...promptArgs) {
+    let p = this.pickPrompter({ browsingContext, modalType, async: true });
+    return p.promptAuth(...promptArgs);
+  },
+};
+
+// Common utils not specific to a particular prompter style.
+var InternalPromptUtils = {
+  getLocalizedString(key, formatArgs) {
+    if (formatArgs) {
+      return this.strBundle.formatStringFromName(key, formatArgs);
+    }
+    return this.strBundle.GetStringFromName(key);
+  },
+
+  confirmExHelper(flags, button0, button1, button2) {
+    const BUTTON_DEFAULT_MASK = 0x03000000;
+    let defaultButtonNum = (flags & BUTTON_DEFAULT_MASK) >> 24;
+    let isDelayEnabled = flags & Ci.nsIPrompt.BUTTON_DELAY_ENABLE;
+
+    // Flags can be used to select a specific pre-defined button label or
+    // a caller-supplied string (button0/button1/button2). If no flags are
+    // set for a button, then the button won't be shown.
+    let argText = [button0, button1, button2];
+    let buttonLabels = [null, null, null];
+    for (let i = 0; i < 3; i++) {
+      let buttonLabel;
+      switch (flags & 0xff) {
+        case Ci.nsIPrompt.BUTTON_TITLE_OK:
+          buttonLabel = this.getLocalizedString("OK");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_CANCEL:
+          buttonLabel = this.getLocalizedString("Cancel");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_YES:
+          buttonLabel = this.getLocalizedString("Yes");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_NO:
+          buttonLabel = this.getLocalizedString("No");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_SAVE:
+          buttonLabel = this.getLocalizedString("Save");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_DONT_SAVE:
+          buttonLabel = this.getLocalizedString("DontSave");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_REVERT:
+          buttonLabel = this.getLocalizedString("Revert");
+          break;
+        case Ci.nsIPrompt.BUTTON_TITLE_IS_STRING:
+          buttonLabel = argText[i];
+          break;
+      }
+      if (buttonLabel) {
+        buttonLabels[i] = buttonLabel;
+      }
+      flags >>= 8;
+    }
+
+    return [
+      buttonLabels[0],
+      buttonLabels[1],
+      buttonLabels[2],
+      defaultButtonNum,
+      isDelayEnabled,
+    ];
+  },
+
+  getAuthInfo(authInfo) {
+    let username, password;
+
+    let flags = authInfo.flags;
+    if (flags & Ci.nsIAuthInformation.NEED_DOMAIN && authInfo.domain) {
+      username = authInfo.domain + "\\" + authInfo.username;
+    } else {
+      username = authInfo.username;
+    }
+
+    password = authInfo.password;
+
+    return [username, password];
+  },
+
+  setAuthInfo(authInfo, username, password) {
+    let flags = authInfo.flags;
+    if (flags & Ci.nsIAuthInformation.NEED_DOMAIN) {
+      // Domain is separated from username by a backslash
+      let idx = username.indexOf("\\");
+      if (idx == -1) {
+        authInfo.username = username;
+      } else {
+        authInfo.domain = username.substring(0, idx);
+        authInfo.username = username.substring(idx + 1);
+      }
+    } else {
+      authInfo.username = username;
+    }
+    authInfo.password = password;
+  },
+
+  /**
+   * Strip out things like userPass and path for display.
+   */
+  getFormattedHostname(uri) {
+    return uri.scheme + "://" + uri.hostPort;
+  },
+
+  // Note: there's a similar implementation in the login manager.
+  getAuthTarget(aChannel, aAuthInfo) {
+    let displayHost, realm;
+
+    // If our proxy is demanding authentication, don't use the
+    // channel's actual destination.
+    if (aAuthInfo.flags & Ci.nsIAuthInformation.AUTH_PROXY) {
+      if (!(aChannel instanceof Ci.nsIProxiedChannel)) {
+        throw new Error("proxy auth needs nsIProxiedChannel");
+      }
+
+      let info = aChannel.proxyInfo;
+      if (!info) {
+        throw new Error("proxy auth needs nsIProxyInfo");
+      }
+
+      // Proxies don't have a scheme, but we'll use "moz-proxy://"
+      // so that it's more obvious what the login is for.
+      let idnService = Cc["@mozilla.org/network/idn-service;1"].getService(
+        Ci.nsIIDNService
+      );
+      displayHost =
+        "moz-proxy://" +
+        idnService.convertUTF8toACE(info.host) +
+        ":" +
+        info.port;
+      realm = aAuthInfo.realm;
+      if (!realm) {
+        realm = displayHost;
+      }
+
+      return { realm, displayHost };
+    }
+
+    displayHost = this.getFormattedHostname(aChannel.URI);
+    let displayHostOnly = aChannel.URI.hostPort;
+
+    // If a HTTP WWW-Authenticate header specified a realm, that value
+    // will be available here. If it wasn't set or wasn't HTTP, we'll use
+    // the formatted hostname instead.
+    realm = aAuthInfo.realm;
+    if (!realm) {
+      realm = displayHost;
+    }
+
+    return { realm, displayHostOnly, displayHost };
+  },
+
+  makeAuthMessage(prompt, channel, authInfo) {
+    if (prompt.modalType != MODAL_TYPE_TAB) {
+      return this._legacyMakeAuthMessage(channel, authInfo);
+    }
+
+    let isProxy = authInfo.flags & Ci.nsIAuthInformation.AUTH_PROXY;
+    let isPassOnly = authInfo.flags & Ci.nsIAuthInformation.ONLY_PASSWORD;
+    let isCrossOrig =
+      authInfo.flags & Ci.nsIAuthInformation.CROSS_ORIGIN_SUB_RESOURCE;
+    let username = authInfo.username;
+
+    // We use the realm and displayHost only for proxy auth,
+    // and the displayHostOnly (hostPort) only for x-origin auth prompts.
+    // Otherwise we rely on the title of the dialog displaying the correct
+    // title.
+    let { displayHost, realm, displayHostOnly } = this.getAuthTarget(
+      channel,
+      authInfo
+    );
+
+    if (isProxy) {
+      // The realm is server-controlled. Trim it if it's very long, to
+      // avoid the dialog becoming unusable.
+      // For background, see https://bugzilla.mozilla.org/show_bug.cgi?id=244273
+      if (realm.length > 150) {
+        realm = realm.substring(0, 150);
+        // Append "..." (or localized equivalent).
+        realm += this.ellipsis;
+      }
+
+      return this.getLocalizedString("EnterLoginForProxy3", [
+        realm,
+        displayHost,
+      ]);
+    }
+    if (isPassOnly) {
+      return this.getLocalizedString("EnterPasswordOnlyFor", [username]);
+    }
+    if (isCrossOrig) {
+      return this.getLocalizedString("EnterCredentialsCrossOrigin", [
+        displayHostOnly,
+      ]);
+    }
+    return this.getLocalizedString("EnterCredentials");
+  },
+
+  _legacyMakeAuthMessage(channel, authInfo) {
+    let isProxy = authInfo.flags & Ci.nsIAuthInformation.AUTH_PROXY;
+    let isPassOnly = authInfo.flags & Ci.nsIAuthInformation.ONLY_PASSWORD;
+    let isCrossOrig =
+      authInfo.flags & Ci.nsIAuthInformation.CROSS_ORIGIN_SUB_RESOURCE;
+
+    let username = authInfo.username;
+    let { displayHost, realm } = this.getAuthTarget(channel, authInfo);
+
+    // Suppress "the site says: $realm" when we synthesized a missing realm.
+    if (!authInfo.realm && !isProxy) {
+      realm = "";
+    }
+
+    // The realm is server-controlled. Trim it if it's very long, to
+    // avoid the dialog becoming unusable.
+    // For background, see https://bugzilla.mozilla.org/show_bug.cgi?id=244273
+    if (realm.length > 150) {
+      realm = realm.substring(0, 150);
+      // Append "..." (or localized equivalent).
+      realm += this.ellipsis;
+    }
+
+    let text;
+    if (isProxy) {
+      text = this.getLocalizedString("EnterLoginForProxy3", [
+        realm,
+        displayHost,
+      ]);
+    } else if (isPassOnly) {
+      text = this.getLocalizedString("EnterPasswordFor", [
+        username,
+        displayHost,
+      ]);
+    } else if (isCrossOrig) {
+      text = this.getLocalizedString("EnterUserPasswordForCrossOrigin2", [
+        displayHost,
+      ]);
+    } else if (!realm) {
+      text = this.getLocalizedString("EnterUserPasswordFor2", [displayHost]);
+    } else {
+      text = this.getLocalizedString("EnterLoginForRealm3", [
+        realm,
+        displayHost,
+      ]);
+    }
+
+    return text;
+  },
+
+  getBrandFullName() {
+    return this.brandBundle.GetStringFromName("brandFullName");
+  },
+};
+
+XPCOMUtils.defineLazyGetter(InternalPromptUtils, "strBundle", function () {
+  let bundle = Services.strings.createBundle(
+    "chrome://global/locale/commonDialogs.properties"
+  );
+  if (!bundle) {
+    throw new Error("String bundle for Prompter not present!");
+  }
+  return bundle;
+});
+
+XPCOMUtils.defineLazyGetter(InternalPromptUtils, "brandBundle", function () {
+  let bundle = Services.strings.createBundle(
+    "chrome://branding/locale/brand.properties"
+  );
+  if (!bundle) {
+    throw new Error("String bundle for branding not present!");
+  }
+  return bundle;
+});
+
+XPCOMUtils.defineLazyGetter(InternalPromptUtils, "ellipsis", function () {
+  let ellipsis = "\u2026";
+  try {
+    ellipsis = Services.prefs.getComplexValue(
+      "intl.ellipsis",
+      Ci.nsIPrefLocalizedString
+    ).data;
+  } catch (e) {}
+  return ellipsis;
+});
+
+class ModalPrompter {
+  constructor({
+    browsingContext = null,
+    domWin = null,
+    modalType = null,
+    async = false,
+  }) {
+    if (browsingContext && domWin) {
+      throw new Error("Pass either browsingContext or domWin");
+    }
+
+    if (domWin) {
+      // We have a domWin, get the associated browsing context
+      this.browsingContext = BrowsingContext.getFromWindow(domWin);
+    } else {
+      this.browsingContext = browsingContext;
+    }
+
+    if (
+      domWin &&
+      (!modalType || modalType == MODAL_TYPE_WINDOW) &&
+      !this.browsingContext?.isContent &&
+      this.browsingContext?.associatedWindow?.gDialogBox
+    ) {
+      modalType = MODAL_TYPE_INTERNAL_WINDOW;
+    }
+
+    // Use given modal type or fallback to default
+    this.modalType = modalType || ModalPrompter.defaultModalType;
+
+    this.async = async;
+
+    this.QueryInterface = ChromeUtils.generateQI([
+      "nsIPrompt",
+      "nsIAuthPrompt",
+      "nsIAuthPrompt2",
+      "nsIWritablePropertyBag2",
+    ]);
+  }
+
+  set modalType(modalType) {
+    // Setting modal type window is always allowed
+    if (modalType == MODAL_TYPE_WINDOW) {
+      this._modalType = modalType;
+      return;
+    }
+
+    // For content prompts for non-content windows, use window prompts:
+    if (modalType == MODAL_TYPE_CONTENT && !this.browsingContext?.isContent) {
+      this._modalType = MODAL_TYPE_WINDOW;
+      return;
+    }
+
+    // We can't use content / tab prompts if we don't have a suitable parent.
+    if (
+      !this.browsingContext?.isContent &&
+      modalType != MODAL_TYPE_INTERNAL_WINDOW
+    ) {
+      // Only show this error if we're not about to fall back again and show a different one.
+      if (this.browsingContext?.associatedWindow?.gDialogBox) {
+        console.error(
+          "Prompter: Browser not available. Falling back to internal window prompt."
+        );
+      }
+      modalType = MODAL_TYPE_INTERNAL_WINDOW;
+    }
+
+    if (
+      modalType == MODAL_TYPE_INTERNAL_WINDOW &&
+      (this.browsingContext?.isContent ||
+        !this.browsingContext?.associatedWindow?.gDialogBox)
+    ) {
+      console.error(
+        "Prompter: internal dialogs not available in this context. Falling back to window prompt."
+      );
+      modalType = MODAL_TYPE_WINDOW;
+    }
+
+    this._modalType = modalType;
+  }
+
+  get modalType() {
+    return this._modalType;
+  }
+
+  /* ---------- internal methods ---------- */
+
+  /**
+   * Synchronous wrapper around {@link ModalPrompter#openPrompt}
+   * @param {Object} args Prompt arguments. When prompt has been closed, they are updated to reflect the result state.
+   */
+  openPromptSync(args) {
+    let closed = false;
+    this.openPrompt(args)
+      .then(returnedArgs => {
+        if (returnedArgs) {
+          for (let key in returnedArgs) {
+            args[key] = returnedArgs[key];
+          }
+        }
+      })
+      .finally(() => {
+        closed = true;
+      });
+    Services.tm.spinEventLoopUntilOrQuit(
+      "prompts/Prompter.jsm:openPromptSync",
+      () => closed
+    );
+  }
+
+  async openPrompt(args) {
+    if (!this.browsingContext) {
+      // We don't have a browsing context, fallback to a window prompt.
+      args.modalType = MODAL_TYPE_WINDOW;
+      this.openWindowPrompt(null, args);
+      return args;
+    }
+
+    if (this._modalType == MODAL_TYPE_INTERNAL_WINDOW) {
+      await this.openInternalWindowPrompt(
+        this.browsingContext.associatedWindow,
+        args
+      );
+      return args;
+    }
+
+    // Select prompts are not part of CommonDialog
+    // and thus not supported as tab or content prompts yet. See Bug 1622817.
+    // Once they are integrated this override should be removed.
+    if (args.promptType == "select" && this.modalType !== MODAL_TYPE_WINDOW) {
+      console.error(
+        "Prompter: 'select' prompts do not support tab/content prompting. Falling back to window prompt."
+      );
+      args.modalType = MODAL_TYPE_WINDOW;
+    } else {
+      args.modalType = this.modalType;
+    }
+
+    const IS_CONTENT =
+      Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_CONTENT;
+
+    let actor;
+    try {
+      if (IS_CONTENT) {
+        // When in the content, get the PromptChild actor.
+        actor =
+          this.browsingContext.window.windowGlobalChild.getActor("Prompt");
+      } else {
+        // When in the parent, get the PromptParent actor.
+        actor = this.browsingContext.currentWindowGlobal.getActor("Prompt");
+      }
+    } catch (_) {
+      // We can't get the prompt actor, fallback to window prompt.
+      let parentWin;
+      // If given a chrome BC we can try to get its window
+      if (!this.browsingContext.isContent && this.browsingContext.window) {
+        parentWin = this.browsingContext.window;
+      } else {
+        // Try to get the window which is the browsers parent
+        parentWin = this.browsingContext.top?.embedderElement?.ownerGlobal;
+      }
+      this.openWindowPrompt(parentWin, args);
+      return args;
+    }
+
+    /* For prompts with a channel, we want to show the origin requesting
+     * authentication. This is different from the prompt principal,
+     * which is based on the document loaded in the browsing context over
+     * which the prompt appears. So if page foo.com loads bar.com, and the
+     * latter asks for auth, we want that bar.com's origin, not foo.com.
+     * To avoid confusion, we use different properties
+     * (authOrigin / promptPrincipal) to track this information.
+     */
+    if (args.channel) {
+      try {
+        args.authOrigin = args.channel.URI.hostPort;
+      } catch (ex) {
+        args.authOrigin = args.channel.URI.prePath;
+      }
+      args.isInsecureAuth =
+        args.channel.URI.schemeIs("http") &&
+        !args.channel.loadInfo.isTopLevelLoad;
+      // whether we are going to prompt the user for their credentials for a different base domain.
+      // When true, auth prompt spoofing protection mechanisms will be triggered (see bug 791594).
+      args.isTopLevelCrossDomainAuth = false;
+      // We don't support auth prompt spoofing protections for sub resources and window prompts
+      if (
+        args.modalType == MODAL_TYPE_TAB &&
+        args.channel.loadInfo.isTopLevelLoad
+      ) {
+        // check if this is a request from a third party
+        try {
+          args.isTopLevelCrossDomainAuth =
+            this.browsingContext.currentWindowGlobal?.documentPrincipal?.isThirdPartyURI(
+              args.channel.URI
+            );
+        } catch (e) {
+          // isThirdPartyURI failes for about:/blob/data URIs
+          console.warn("nsPrompter: isThirdPartyURI failed: " + e);
+        }
+      }
+    } else {
+      args.promptPrincipal =
+        this.browsingContext.window?.document.nodePrincipal;
+    }
+    if (IS_CONTENT) {
+      let docShell = this.browsingContext.docShell;
+      let inPermitUnload = docShell?.contentViewer?.inPermitUnload;
+      args.inPermitUnload = inPermitUnload;
+      let eventDetail = Cu.cloneInto(
+        {
+          tabPrompt: this.modalType != MODAL_TYPE_WINDOW,
+          inPermitUnload,
+        },
+        this.browsingContext.window
+      );
+      PromptUtils.fireDialogEvent(
+        this.browsingContext.window,
+        "DOMWillOpenModalDialog",
+        null,
+        eventDetail
+      );
+
+      // Put content window in the modal state while the prompt is open.
+      let windowUtils = this.browsingContext.window?.windowUtils;
+      if (windowUtils) {
+        windowUtils.enterModalState();
+      }
+    } else if (args.inPermitUnload) {
+      args.promptPrincipal =
+        this.browsingContext.currentWindowGlobal.documentPrincipal;
+    }
+
+    // It is technically possible for multiple prompts to be sent from a single
+    // BrowsingContext. See bug 1266353. We use a randomly generated UUID to
+    // differentiate between the different prompts.
+    let id = "id" + Services.uuid.generateUUID().toString();
+
+    args._remoteId = id;
+
+    let returnedArgs;
+    try {
+      if (IS_CONTENT) {
+        // If we're in the content process, send a message to the PromptParent
+        // window actor.
+        returnedArgs = await actor.sendQuery("Prompt:Open", args);
+      } else {
+        // If we're in the parent process we already have the parent actor.
+        // We can call its message handler directly.
+        returnedArgs = await actor.receiveMessage({
+          name: "Prompt:Open",
+          data: args,
+        });
+      }
+
+      if (returnedArgs?.promptAborted) {
+        throw Components.Exception(
+          "prompt aborted by user",
+          Cr.NS_ERROR_NOT_AVAILABLE
+        );
+      }
+    } finally {
+      if (IS_CONTENT) {
+        let windowUtils = this.browsingContext.window?.windowUtils;
+        if (windowUtils) {
+          windowUtils.leaveModalState();
+        }
+        PromptUtils.fireDialogEvent(
+          this.browsingContext.window,
+          "DOMModalDialogClosed"
+        );
+      }
+    }
+    return returnedArgs;
+  }
+
+  /**
+   * Open a window modal prompt
+   *
+   * There's an implied contract that says modal prompts should still work when
+   * no "parent" window is passed for the dialog (eg, the "Master Password"
+   * dialog does this).  These prompts must be shown even if there are *no*
+   * visible windows at all.
+   * We try and find a window to use as the parent, but don't consider if that
+   * is visible before showing the prompt. parentWindow may still be null if
+   * there are _no_ windows open.
+   * @param {Window} [parentWindow] - The parent window for the prompt, may be
+   *        null.
+   * @param {Object} args - Prompt options and return values.
+   */
+  openWindowPrompt(parentWindow = null, args) {
+    let uri = args.promptType == "select" ? SELECT_DIALOG : COMMON_DIALOG;
+    let propBag = PromptUtils.objectToPropBag(args);
+    Services.ww.openWindow(
+      parentWindow || Services.ww.activeWindow,
+      uri,
+      "_blank",
+      "centerscreen,chrome,modal,titlebar",
+      propBag
+    );
+    PromptUtils.propBagToObject(propBag, args);
+  }
+
+  async openInternalWindowPrompt(parentWindow, args) {
+    if (!parentWindow?.gDialogBox || !ModalPrompter.windowPromptSubDialog) {
+      this.openWindowPrompt(parentWindow, args);
+      return;
+    }
+    let propBag = PromptUtils.objectToPropBag(args);
+    propBag.setProperty("async", this.async);
+    let uri = args.promptType == "select" ? SELECT_DIALOG : COMMON_DIALOG;
+    await parentWindow.gDialogBox.open(uri, propBag);
+    propBag.deleteProperty("async");
+    PromptUtils.propBagToObject(propBag, args);
+  }
+
+  /**
+   * Calls async prompt method and optionally runs promise chained task on
+   * result data. Converts result data to nsIPropertyBag.
+   * @param {Object} args - Prompt arguments.
+   * @param {Function} [task] - Function which is called with the modified
+   *  prompt args object once the prompt has been closed. Must return a
+   *  result object for the prompt caller.
+   * @returns {Promise<nsIPropertyBag>} - Resolves with a property bag holding the
+   * prompt result properties. Resolves once prompt has been closed.
+   */
+  async openPromptAsync(args, task) {
+    let result = await this.openPrompt(args);
+    // If task is not defined, the prompt method does not return
+    // anything. In this case we can resolve without value.
+    if (!task) {
+      return undefined;
+    }
+    // Convert task result to nsIPropertyBag and resolve
+    let taskResult = task(result);
+    if (!(taskResult instanceof Object)) {
+      throw new Error("task must return object");
+    }
+    return PromptUtils.objectToPropBag(taskResult);
+  }
+
+  /*
+   * ---------- interface disambiguation ----------
+   *
+   * nsIPrompt and nsIAuthPrompt share 3 method names with slightly
+   * different arguments. All but prompt() have the same number of
+   * arguments, so look at the arg types to figure out how we're being
+   * called. :-(
+   */
+  prompt() {
+    // also, the nsIPrompt flavor has 5 args instead of 6.
+    if (typeof arguments[2] == "object") {
+      return this.nsIPrompt_prompt.apply(this, arguments);
+    }
+    return this.nsIAuthPrompt_prompt.apply(this, arguments);
+  }
+
+  promptUsernameAndPassword() {
+    // Both have 6 args, so use types.
+    if (typeof arguments[2] == "object") {
+      // Add the null channel:
+      let args = Array.from(arguments);
+      args.unshift(null);
+      return this.nsIPrompt_promptUsernameAndPassword.apply(this, args);
+    }
+    return this.nsIAuthPrompt_promptUsernameAndPassword.apply(this, arguments);
+  }
+
+  promptPassword() {
+    // Both have 5 args, so use types.
+    if (typeof arguments[2] == "object") {
+      // Add the null channel:
+      let args = Array.from(arguments);
+      args.unshift(null);
+      return this.nsIPrompt_promptPassword.apply(this, args);
+    }
+    return this.nsIAuthPrompt_promptPassword.apply(this, arguments);
+  }
+
+  /* ----------  nsIPrompt  ---------- */
+
+  alert(title, text) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Alert");
+    }
+
+    let args = {
+      promptType: "alert",
+      title,
+      text,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args);
+    }
+
+    return this.openPromptSync(args);
+  }
+
+  alertCheck(title, text, checkLabel, checkValue) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Alert");
+    }
+
+    // For sync calls checkValue is an XPCOM inout. XPCOM wraps primitves in
+    // objects for call by reference.
+    // The async version of this method uses call by value.
+    let checked = this.async ? checkValue : checkValue.value;
+
+    let args = {
+      promptType: "alertCheck",
+      title,
+      text,
+      checkLabel,
+      checked,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        checked: result.checked,
+      }));
+    }
+
+    this.openPromptSync(args);
+    checkValue.value = args.checked;
+    return undefined;
+  }
+
+  confirm(title, text) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Confirm");
+    }
+
+    let args = {
+      promptType: "confirm",
+      title,
+      text,
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({ ok: result.ok }));
+    }
+
+    this.openPromptSync(args);
+    return args.ok;
+  }
+
+  confirmCheck(title, text, checkLabel, checkValue) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("ConfirmCheck");
+    }
+
+    let checked = this.async ? checkValue : checkValue.value;
+
+    let args = {
+      promptType: "confirmCheck",
+      title,
+      text,
+      checkLabel,
+      checked,
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        // Checkbox state always returned, even if cancel clicked.
+        checked: result.checked,
+        // Did user click Ok or Cancel?
+        ok: result.ok,
+      }));
+    }
+
+    this.openPromptSync(args);
+    checkValue.value = args.checked;
+    return args.ok;
+  }
+
+  confirmEx(
+    title,
+    text,
+    flags,
+    button0,
+    button1,
+    button2,
+    checkLabel,
+    checkValue,
+    extraArgs = {}
+  ) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Confirm");
+    }
+
+    let args = {
+      promptType: "confirmEx",
+      title,
+      text,
+      checkLabel,
+      checked: this.async ? checkValue : checkValue.value,
+      ok: false,
+      buttonNumClicked: 1,
+      ...extraArgs,
+    };
+
+    let [label0, label1, label2, defaultButtonNum, isDelayEnabled] =
+      InternalPromptUtils.confirmExHelper(flags, button0, button1, button2);
+
+    args.defaultButtonNum = defaultButtonNum;
+    args.enableDelay = isDelayEnabled;
+
+    if (label0) {
+      args.button0Label = label0;
+      if (label1) {
+        args.button1Label = label1;
+        if (label2) {
+          args.button2Label = label2;
+        }
+      }
+    }
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        checked: !!result.checked,
+        buttonNumClicked: result.buttonNumClicked,
+      }));
+    }
+
+    this.openPromptSync(args);
+    checkValue.value = args.checked;
+    return args.buttonNumClicked;
+  }
+
+  nsIPrompt_prompt(title, text, value, checkLabel, checkValue) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Prompt");
+    }
+
+    let args = {
+      promptType: "prompt",
+      title,
+      text,
+      value: this.async ? value : value.value,
+      checkLabel,
+      checked: this.async ? checkValue : checkValue.value,
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        checked: !!result.checked,
+        value: result.value,
+        ok: result.ok,
+      }));
+    }
+
+    this.openPromptSync(args);
+
+    // Did user click Ok or Cancel?
+    let ok = args.ok;
+    if (ok) {
+      checkValue.value = args.checked;
+      value.value = args.value;
+    }
+
+    return ok;
+  }
+
+  nsIPrompt_promptUsernameAndPassword(channel, title, text, user, pass) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString(
+        "PromptUsernameAndPassword3",
+        [InternalPromptUtils.getBrandFullName()]
+      );
+    }
+
+    let args = {
+      channel,
+      promptType: "promptUserAndPass",
+      title,
+      text,
+      user: this.async ? user : user.value,
+      pass: this.async ? pass : pass.value,
+      button0Label: InternalPromptUtils.getLocalizedString("SignIn"),
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        user: result.user,
+        pass: result.pass,
+        ok: result.ok,
+      }));
+    }
+
+    this.openPromptSync(args);
+
+    // Did user click Ok or Cancel?
+    let ok = args.ok;
+    if (ok) {
+      user.value = args.user;
+      pass.value = args.pass;
+    }
+
+    return ok;
+  }
+
+  nsIPrompt_promptPassword(channel, title, text, pass) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("PromptPassword3", [
+        InternalPromptUtils.getBrandFullName(),
+      ]);
+    }
+
+    let args = {
+      channel,
+      promptType: "promptPassword",
+      title,
+      text,
+      pass: this.async ? pass : pass.value,
+      button0Label: InternalPromptUtils.getLocalizedString("SignIn"),
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        pass: result.pass,
+        ok: result.ok,
+      }));
+    }
+
+    this.openPromptSync(args);
+
+    // Did user click Ok or Cancel?
+    let ok = args.ok;
+    if (ok) {
+      pass.value = args.pass;
+    }
+
+    return ok;
+  }
+
+  select(title, text, list, selected) {
+    if (!title) {
+      title = InternalPromptUtils.getLocalizedString("Select");
+    }
+
+    let args = {
+      promptType: "select",
+      title,
+      text,
+      list,
+      selected: -1,
+      ok: false,
+    };
+
+    if (this.async) {
+      return this.openPromptAsync(args, result => ({
+        selected: result.selected,
+        ok: result.ok,
+      }));
+    }
+
+    this.openPromptSync(args);
+
+    // Did user click Ok or Cancel?
+    let ok = args.ok;
+    if (ok) {
+      selected.value = args.selected;
+    }
+
+    return ok;
+  }
+
+  /* ----------  nsIAuthPrompt  ---------- */
+
+  nsIAuthPrompt_prompt(
+    title,
+    text,
+    passwordRealm,
+    savePassword,
+    defaultText,
+    result
+  ) {
+    // The passwordRealm and savePassword args were ignored by nsPrompt.cpp
+    if (defaultText) {
+      result.value = defaultText;
+    }
+    return this.nsIPrompt_prompt(title, text, result, null, {});
+  }
+
+  nsIAuthPrompt_promptUsernameAndPassword(
+    title,
+    text,
+    passwordRealm,
+    savePassword,
+    user,
+    pass
+  ) {
+    // The passwordRealm and savePassword args were ignored by nsPrompt.cpp
+    return this.nsIPrompt_promptUsernameAndPassword(
+      null,
+      title,
+      text,
+      user,
+      pass
+    );
+  }
+
+  nsIAuthPrompt_promptPassword(title, text, passwordRealm, savePassword, pass) {
+    // The passwordRealm and savePassword args were ignored by nsPrompt.cpp,
+    // and we don't have a channel here.
+    return this.nsIPrompt_promptPassword(null, title, text, pass);
+  }
+
+  /* ----------  nsIAuthPrompt2  ---------- */
+
+  promptAuth(channel, level, authInfo) {
+    let message = InternalPromptUtils.makeAuthMessage(this, channel, authInfo);
+
+    let [username, password] = InternalPromptUtils.getAuthInfo(authInfo);
+
+    let userParam = this.async ? username : { value: username };
+    let passParam = this.async ? password : { value: password };
+
+    let result;
+    if (authInfo.flags & Ci.nsIAuthInformation.ONLY_PASSWORD) {
+      result = this.nsIPrompt_promptPassword(channel, null, message, passParam);
+    } else {
+      result = this.nsIPrompt_promptUsernameAndPassword(
+        channel,
+        null,
+        message,
+        userParam,
+        passParam
+      );
+    }
+
+    // For the async case result is an nsIPropertyBag with prompt results.
+    if (this.async) {
+      return result.then(bag => {
+        let ok = bag.getProperty("ok");
+        if (ok) {
+          let username = bag.getProperty("user");
+          let password = bag.getProperty("pass");
+          InternalPromptUtils.setAuthInfo(authInfo, username, password);
+        }
+        return ok;
+      });
+    }
+
+    // For the sync case result is the "ok" boolean which indicates whether
+    // the user has confirmed the dialog.
+    if (result) {
+      InternalPromptUtils.setAuthInfo(
+        authInfo,
+        userParam.value,
+        passParam.value
+      );
+    }
+    return result;
+  }
+
+  asyncPromptAuth(
+    channel,
+    callback,
+    context,
+    level,
+    authInfo,
+    checkLabel,
+    checkValue
+  ) {
+    // Nothing calls this directly; netwerk ends up going through
+    // nsIPromptService::GetPrompt, which delegates to login manager.
+    // Login manger handles the async bits itself, and only calls out
+    // promptAuth, never asyncPromptAuth.
+    //
+    // Bug 565582 will change this.
+    throw Components.Exception("", Cr.NS_ERROR_NOT_IMPLEMENTED);
+  }
+
+  /* ----------  nsIWritablePropertyBag2 ---------- */
+  // Legacy way to set modal type when prompting via nsIPrompt.
+  // Please prompt via nsIPromptService. This will be removed in the future.
+  setPropertyAsUint32(name, value) {
+    if (name == "modalType") {
+      this.modalType = value;
+    } else {
+      throw Components.Exception("", Cr.NS_ERROR_ILLEGAL_VALUE);
+    }
+  }
+}
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  ModalPrompter,
+  "defaultModalType",
+  "prompts.defaultModalType",
+  MODAL_TYPE_WINDOW
+);
+
+XPCOMUtils.defineLazyPreferenceGetter(
+  ModalPrompter,
+  "windowPromptSubDialog",
+  "prompts.windowPromptSubDialog",
+  false
+);
+
+export function AuthPromptAdapterFactory() {}
+AuthPromptAdapterFactory.prototype = {
+  classID: Components.ID("{6e134924-6c3a-4d86-81ac-69432dd971dc}"),
+  QueryInterface: ChromeUtils.generateQI(["nsIAuthPromptAdapterFactory"]),
+
+  /* ----------  nsIAuthPromptAdapterFactory ---------- */
+
+  createAdapter(oldPrompter) {
+    return new AuthPromptAdapter(oldPrompter);
+  },
+};
+
+// Takes an nsIAuthPrompt implementation, wraps it with a nsIAuthPrompt2 shell.
+function AuthPromptAdapter(oldPrompter) {
+  this.oldPrompter = oldPrompter;
+}
+AuthPromptAdapter.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIAuthPrompt2"]),
+  oldPrompter: null,
+
+  /* ----------  nsIAuthPrompt2 ---------- */
+
+  promptAuth(channel, level, authInfo, checkLabel, checkValue) {
+    let message = InternalPromptUtils.makeAuthMessage(
+      this.oldPrompter,
+      channel,
+      authInfo
+    );
+
+    let [username, password] = InternalPromptUtils.getAuthInfo(authInfo);
+    let userParam = { value: username };
+    let passParam = { value: password };
+
+    let { displayHost, realm } = InternalPromptUtils.getAuthTarget(
+      channel,
+      authInfo
+    );
+    let authTarget = displayHost + " (" + realm + ")";
+
+    let ok;
+    if (authInfo.flags & Ci.nsIAuthInformation.ONLY_PASSWORD) {
+      ok = this.oldPrompter.promptPassword(
+        null,
+        message,
+        authTarget,
+        Ci.nsIAuthPrompt.SAVE_PASSWORD_PERMANENTLY,
+        passParam
+      );
+    } else {
+      ok = this.oldPrompter.promptUsernameAndPassword(
+        null,
+        message,
+        authTarget,
+        Ci.nsIAuthPrompt.SAVE_PASSWORD_PERMANENTLY,
+        userParam,
+        passParam
+      );
+    }
+
+    if (ok) {
+      InternalPromptUtils.setAuthInfo(
+        authInfo,
+        userParam.value,
+        passParam.value
+      );
+    }
+    return ok;
+  },
+
+  asyncPromptAuth(
+    channel,
+    callback,
+    context,
+    level,
+    authInfo,
+    checkLabel,
+    checkValue
+  ) {
+    throw Components.Exception("", Cr.NS_ERROR_NOT_IMPLEMENTED);
+  },
+};
diff --git a/toolkit/components/prompts/src/components.conf b/toolkit/components/prompts/src/components.conf
new file mode 100644
index 0000000000..7be17963ed
--- /dev/null
+++ b/toolkit/components/prompts/src/components.conf
@@ -0,0 +1,26 @@
+# -*- 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 = [
+    {
+        'cid': '{6e134924-6c3a-4d86-81ac-69432dd971dc}',
+        'contract_ids': ['@mozilla.org/network/authprompt-adapter-factory;1'],
+        'esModule': 'resource://gre/modules/Prompter.sys.mjs',
+        'constructor': 'AuthPromptAdapterFactory',
+    },
+]
+
+if buildconfig.substs['MOZ_WIDGET_TOOLKIT'] != 'android':
+    Classes += [
+        {
+            'js_name': 'prompt',
+            'cid': '{1c978d25-b37f-43a8-a2d6-0c7a239ead87}',
+            'contract_ids': ['@mozilla.org/prompter;1'],
+            'interfaces': ['nsIPromptService'],
+            'esModule': 'resource://gre/modules/Prompter.sys.mjs',
+            'constructor': 'Prompter',
+        },
+    ]
diff --git a/toolkit/components/prompts/src/moz.build b/toolkit/components/prompts/src/moz.build
new file mode 100644
index 0000000000..00eea500c5
--- /dev/null
+++ b/toolkit/components/prompts/src/moz.build
@@ -0,0 +1,15 @@
+# -*- 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/.
+
+EXTRA_JS_MODULES += [
+    "CommonDialog.sys.mjs",
+    "Prompter.sys.mjs",
+    "PromptUtils.sys.mjs",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
diff --git a/toolkit/components/prompts/test/.eslintrc.js b/toolkit/components/prompts/test/.eslintrc.js
new file mode 100644
index 0000000000..af973e82fe
--- /dev/null
+++ b/toolkit/components/prompts/test/.eslintrc.js
@@ -0,0 +1,8 @@
+"use strict";
+
+module.exports = {
+  rules: {
+    // ownerGlobal doesn't exist in content privileged windows.
+    "mozilla/use-ownerGlobal": "off",
+  },
+};
diff --git a/toolkit/components/prompts/test/PromptTestUtils.sys.mjs b/toolkit/components/prompts/test/PromptTestUtils.sys.mjs
new file mode 100644
index 0000000000..c55259ce1b
--- /dev/null
+++ b/toolkit/components/prompts/test/PromptTestUtils.sys.mjs
@@ -0,0 +1,237 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Utility module for tests to interact with prompts spawned by nsIPrompt or
+ * nsIPromptService.
+ */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { BrowserTestUtils } from "resource://testing-common/BrowserTestUtils.sys.mjs";
+import { TestUtils } from "resource://testing-common/TestUtils.sys.mjs";
+
+const kPrefs = {};
+
+// Whether prompts with modal type TAB are shown as SubDialog (true) or
+// TabModalPrompt (false).
+XPCOMUtils.defineLazyPreferenceGetter(
+  kPrefs,
+  "tabPromptSubDialogEnabled",
+  "prompts.tabChromePromptSubDialog",
+  false
+);
+
+// Whether web content prompts (alert etc.) are shown as SubDialog (true)
+// or TabModalPrompt (false)
+XPCOMUtils.defineLazyPreferenceGetter(
+  kPrefs,
+  "contentPromptSubDialogEnabled",
+  "prompts.contentPromptSubDialog",
+  false
+);
+
+function isCommonDialog(modalType) {
+  return (
+    modalType === Services.prompt.MODAL_TYPE_WINDOW ||
+    (kPrefs.tabPromptSubDialogEnabled &&
+      modalType === Services.prompt.MODAL_TYPE_TAB) ||
+    (kPrefs.contentPromptSubDialogEnabled &&
+      modalType === Services.prompt.MODAL_TYPE_CONTENT)
+  );
+}
+
+export let PromptTestUtils = {
+  /**
+   * Wait for a prompt from nsIPrompt or nsIPromptsService, interact with it and
+   * click the specified button to close it.
+   * @param {Browser|Window} [parent] - Parent of the prompt. This can be
+   * either the parent window or the browser. For tab prompts, if given a
+   * window, the currently selected browser in that window will be used.
+   * @param {Object} promptOptions - @see waitForPrompt
+   * @param {Object} promptActions - @see handlePrompt
+   * @returns {Promise} - A promise which resolves once the prompt has been
+   * closed.
+   */
+  async handleNextPrompt(parent, promptOptions, promptActions) {
+    let dialog = await this.waitForPrompt(parent, promptOptions);
+    return this.handlePrompt(dialog, promptActions);
+  },
+
+  /**
+   * Interact with an existing prompt and close it.
+   * @param {Dialog} dialog - The dialog instance associated with the prompt.
+   * @param {Object} [actions] - Options on how to interact with the
+   * prompt and how to close it.
+   * @param {Boolean} [actions.checkboxState] - Set the checkbox state.
+   * true = checked, false = unchecked.
+   * @param {Number} [actions.buttonNumClick] - Which button to click to close
+   * the prompt.
+   * @param {String} [actions.loginInput] - Input text for the login text field.
+   * This field is also used for text input for the "prompt" type.
+   * @param {String} [actions.passwordInput] - Input text for the password text
+   * field.
+   * @returns {Promise} - A promise which resolves once the prompt has been
+   * closed.
+   */
+  handlePrompt(
+    dialog,
+    {
+      checkboxState = null,
+      buttonNumClick = 0,
+      loginInput = null,
+      passwordInput = null,
+    } = {}
+  ) {
+    let promptClosePromise;
+
+    // Get parent window to listen for prompt close event
+    let win;
+    if (isCommonDialog(dialog.args.modalType)) {
+      win = dialog.ui.prompt?.opener;
+    } else {
+      // Tab prompts should always have a parent window
+      win = dialog.ui.prompt.win;
+    }
+
+    if (win) {
+      promptClosePromise = BrowserTestUtils.waitForEvent(
+        win,
+        "DOMModalDialogClosed"
+      );
+    } else {
+      // We don't have a parent, wait for window close instead
+      promptClosePromise = BrowserTestUtils.windowClosed(dialog.ui.prompt);
+    }
+
+    if (typeof checkboxState == "boolean") {
+      dialog.ui.checkbox.checked = checkboxState;
+    }
+
+    if (loginInput != null) {
+      dialog.ui.loginTextbox.value = loginInput;
+    }
+
+    if (passwordInput != null) {
+      dialog.ui.password1Textbox.value = passwordInput;
+    }
+
+    let button = dialog.ui["button" + buttonNumClick];
+    if (!button) {
+      throw new Error("Could not find button with index " + buttonNumClick);
+    }
+    button.click();
+
+    return promptClosePromise;
+  },
+
+  /**
+   * Wait for a prompt from nsIPrompt or nsIPromptsService to open.
+   * @param {Browser|Window} [parent] - Parent of the prompt. This can be either
+   * the parent window or the browser. For tab prompts, if given a window, the
+   * currently selected browser in that window will be used.
+   * If not given a parent, the method will return on prompts of any window.
+   * @param {Object} attrs - The prompt attributes to filter for.
+   * @param {Number} attrs.modalType - Whether the expected prompt is a content, tab or window prompt.
+   * nsIPromptService.<MODAL_TYPE_WINDOW|MODAL_TYPE_TAB|MODAL_TYPE_CONTENT>
+   * @param {String} [attrs.promptType] - Common dialog type of the prompt to filter for.
+   *  @see {@link CommonDialog} for possible prompt types.
+   * @returns {Promise<CommonDialog>} - A Promise which resolves with a dialog
+   * object once the prompt has loaded.
+   */
+  async waitForPrompt(parent, { modalType, promptType = null } = {}) {
+    if (!modalType) {
+      throw new Error("modalType is mandatory");
+    }
+
+    // Get window by browser or browser by window, depending on what is passed
+    // via the parent arg. If the caller passes parent=null, both will be null.
+    let parentWindow;
+    let parentBrowser;
+    if (parent) {
+      if (Element.isInstance(parent)) {
+        // Parent is browser
+        parentBrowser = parent;
+        parentWindow = parentBrowser.ownerGlobal;
+      } else if (parent instanceof Ci.nsIDOMChromeWindow) {
+        // Parent is window
+        parentWindow = parent;
+        parentBrowser = parentWindow.gBrowser?.selectedBrowser;
+      } else {
+        throw new Error("Invalid parent. Expected browser or dom window");
+      }
+    }
+
+    let topic = isCommonDialog(modalType)
+      ? "common-dialog-loaded"
+      : "tabmodal-dialog-loaded";
+
+    let dialog;
+    await TestUtils.topicObserved(topic, subject => {
+      // If we are not given a browser, use the currently selected browser of the window
+      let browser =
+        parentBrowser || subject.ownerGlobal.gBrowser?.selectedBrowser;
+      if (isCommonDialog(modalType)) {
+        // Is not associated with given parent window, skip
+        if (parentWindow && subject.opener !== parentWindow) {
+          return false;
+        }
+
+        // For tab prompts, ensure that the associated browser matches.
+        if (browser && modalType == Services.prompt.MODAL_TYPE_TAB) {
+          let dialogBox = parentWindow.gBrowser.getTabDialogBox(browser);
+          let hasMatchingDialog = dialogBox
+            .getTabDialogManager()
+            ._dialogs.some(
+              d => d._frame?.browsingContext == subject.browsingContext
+            );
+          if (!hasMatchingDialog) {
+            return false;
+          }
+        }
+
+        if (browser && modalType == Services.prompt.MODAL_TYPE_CONTENT) {
+          let dialogBox = parentWindow.gBrowser.getTabDialogBox(browser);
+          let hasMatchingDialog = dialogBox
+            .getContentDialogManager()
+            ._dialogs.some(
+              d => d._frame?.browsingContext == subject.browsingContext
+            );
+          if (!hasMatchingDialog) {
+            return false;
+          }
+        }
+
+        // subject is the window object of the prompt which has a Dialog object
+        // attached.
+        dialog = subject.Dialog;
+      } else {
+        // subject is the tabprompt dom node
+        // Get the full prompt object which has the dialog object
+        let prompt = browser.tabModalPromptBox.getPrompt(subject);
+
+        // Is not associated with given parent browser, skip.
+        if (!prompt) {
+          return false;
+        }
+
+        dialog = prompt.Dialog;
+      }
+
+      // Not the modalType we're looking for.
+      // For window prompts dialog.args.modalType is undefined.
+      if (isCommonDialog(modalType) && dialog.args.modalType !== modalType) {
+        return false;
+      }
+
+      // Not the promptType we're looking for.
+      if (promptType && dialog.args.promptType !== promptType) {
+        return false;
+      }
+
+      // Prompt found
+      return true;
+    });
+
+    return dialog;
+  },
+};
diff --git a/toolkit/components/prompts/test/bug619644_inner.html b/toolkit/components/prompts/test/bug619644_inner.html
new file mode 100644
index 0000000000..cecfa78bad
--- /dev/null
+++ b/toolkit/components/prompts/test/bug619644_inner.html
@@ -0,0 +1,7 @@
+<head></head><body><p>Original content</p>
+<script>
+    window.opener.postMessage("", "*");
+    confirm("Message");
+    document.write("Extra content");
+    window.opener.postMessage(document.documentElement.innerHTML, "*");
+</script></body>
diff --git a/toolkit/components/prompts/test/bug625187_iframe.html b/toolkit/components/prompts/test/bug625187_iframe.html
new file mode 100644
index 0000000000..740d59a617
--- /dev/null
+++ b/toolkit/components/prompts/test/bug625187_iframe.html
@@ -0,0 +1,16 @@
+<html>
+<head>
+  <title>Test for Bug 625187 - the iframe</title>
+<!--
+   - Any copyright is dedicated to the Public Domain.
+   - http://creativecommons.org/publicdomain/zero/1.0/
+   -
+   - Contributor(s):
+   -   Mihai Sucan <mihai.sucan@gmail.com>
+   -->
+</head>
+<body>
+<p><button id="btn1" onclick="alert('hello world 2')">Button 2</button></p>
+<p><button id="btn2" onclick="window.parent.alert('hello world 3')">Button 3</button></p>
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/chrome.ini b/toolkit/components/prompts/test/chrome.ini
new file mode 100644
index 0000000000..90eee3a761
--- /dev/null
+++ b/toolkit/components/prompts/test/chrome.ini
@@ -0,0 +1,11 @@
+[DEFAULT]
+support-files =
+  prompt_common.js
+  chromeScript.js
+
+[test_modal_prompts.html]
+skip-if =
+  toolkit == 'android' #android: TIMED_OUT
+  os == 'linux' && (debug || asan || tsan)
+[test_modal_select.html]
+skip-if = toolkit == 'android' #android: TIMED_OUT
diff --git a/toolkit/components/prompts/test/chromeScript.js b/toolkit/components/prompts/test/chromeScript.js
new file mode 100644
index 0000000000..5bdf3606d4
--- /dev/null
+++ b/toolkit/components/prompts/test/chromeScript.js
@@ -0,0 +1,353 @@
+/* eslint-env mozilla/chrome-script */
+
+const { clearInterval, setInterval, setTimeout } = ChromeUtils.importESModule(
+  "resource://gre/modules/Timer.sys.mjs"
+);
+
+const { BrowserTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/BrowserTestUtils.sys.mjs"
+);
+
+var tabSubDialogsEnabled = Services.prefs.getBoolPref(
+  "prompts.tabChromePromptSubDialog",
+  false
+);
+
+var contentPromptSubdialogsEnabled = Services.prefs.getBoolPref(
+  "prompts.contentPromptSubDialog",
+  false
+);
+
+// Define these to make EventUtils happy.
+let window = this;
+let parent = {};
+
+let EventUtils = {};
+Services.scriptloader.loadSubScript(
+  "chrome://mochikit/content/tests/SimpleTest/EventUtils.js",
+  EventUtils
+);
+
+addMessageListener("handlePrompt", msg => {
+  info("Received handlePrompt message");
+  handlePromptWhenItAppears(msg.action, msg.modalType, msg.isSelect);
+});
+
+async function handlePromptWhenItAppears(action, modalType, isSelect) {
+  try {
+    if (!(await handlePrompt(action, modalType, isSelect))) {
+      setTimeout(
+        () => this.handlePromptWhenItAppears(action, modalType, isSelect),
+        100
+      );
+    }
+  } catch (e) {
+    info(`handlePromptWhenItAppears: exception: ${e}`);
+  }
+}
+
+function checkTabModal(prompt, browser) {
+  let doc = browser.ownerDocument;
+
+  let { bottom: toolboxBottom } = doc
+    .getElementById("navigator-toolbox")
+    .getBoundingClientRect();
+
+  let { mainContainer } = prompt.ui;
+
+  let { x, y } = mainContainer.getBoundingClientRect();
+  ok(y > 0, "Container should have y > 0");
+  // Inset by 1px since the corner point doesn't return the frame due to the
+  // border-radius.
+  is(
+    doc.elementFromPoint(x + 1, y + 1).parentNode,
+    mainContainer,
+    "Check tabmodalprompt is visible"
+  );
+
+  info("Click to the left of the dialog over the content area");
+  isnot(
+    doc.elementFromPoint(x - 10, y + 50),
+    browser,
+    "Check clicks on the content area don't go to the browser"
+  );
+  is(
+    doc.elementFromPoint(x - 10, y + 50),
+    prompt.element,
+    "Check clicks on the content area go to the prompt dialog background"
+  );
+
+  if (prompt.args.modalType == Ci.nsIPrompt.MODAL_TYPE_TAB) {
+    ok(
+      y <= toolboxBottom - 5,
+      "Dialog should overlap the toolbox by at least 5px"
+    );
+  } else {
+    ok(y >= toolboxBottom, "Dialog must not overlap with toolbox.");
+  }
+
+  ok(
+    browser.hasAttribute("tabmodalPromptShowing"),
+    "Check browser has @tabmodalPromptShowing"
+  );
+}
+
+async function handlePrompt(action, modalType, isSelect) {
+  info(`handlePrompt: modalType=${modalType}`);
+
+  let ui;
+  let browserWin = Services.wm.getMostRecentWindow("navigator:browser");
+
+  if (
+    (!contentPromptSubdialogsEnabled &&
+      modalType === Services.prompt.MODAL_TYPE_CONTENT) ||
+    (!tabSubDialogsEnabled && modalType === Services.prompt.MODAL_TYPE_TAB)
+  ) {
+    let gBrowser = browserWin.gBrowser;
+    let promptManager = gBrowser.getTabModalPromptBox(gBrowser.selectedBrowser);
+    let prompts = promptManager.listPrompts();
+    if (!prompts.length) {
+      info("handlePrompt: no prompt found. retrying...");
+      return false; // try again in a bit
+    }
+
+    ui = prompts[0].Dialog.ui;
+    checkTabModal(prompts[0], gBrowser.selectedBrowser);
+  } else {
+    let doc = getDialogDoc();
+    if (!doc) {
+      info("handlePrompt: no document found. retrying...");
+      return false; // try again in a bit
+    }
+
+    if (isSelect) {
+      ui = doc;
+    } else {
+      ui = doc.defaultView.Dialog.ui;
+    }
+  }
+
+  let dialogClosed = BrowserTestUtils.waitForEvent(
+    browserWin,
+    "DOMModalDialogClosed"
+  );
+
+  let promptState;
+  if (isSelect) {
+    promptState = getSelectState(ui);
+    dismissSelect(ui, action);
+  } else {
+    promptState = getPromptState(ui);
+    dismissPrompt(ui, action);
+  }
+
+  // Wait until the prompt has been closed before sending callback msg.
+  // Unless the test explicitly doesn't request a button click.
+  if (action.buttonClick !== "none") {
+    info(`handlePrompt: wait for dialogClosed`);
+    await dialogClosed;
+  }
+
+  info(`handlePrompt: send promptHandled`);
+  sendAsyncMessage("promptHandled", { promptState });
+  return true;
+}
+
+function getSelectState(ui) {
+  let listbox = ui.getElementById("list");
+
+  let state = {};
+  state.msg = ui.getElementById("info.txt").value;
+  state.selectedIndex = listbox.selectedIndex;
+  state.items = [];
+
+  for (let i = 0; i < listbox.itemCount; i++) {
+    let item = listbox.getItemAtIndex(i).label;
+    state.items.push(item);
+  }
+
+  return state;
+}
+
+function getPromptState(ui) {
+  let state = {};
+  state.msg = ui.infoBody.textContent;
+  state.infoRowHidden = ui.infoRow?.hidden || false;
+  state.titleHidden = ui.infoTitle.hidden;
+  state.textHidden = ui.loginContainer.hidden;
+  state.passHidden = ui.password1Container.hidden;
+  state.checkHidden = ui.checkboxContainer.hidden;
+  state.checkMsg = state.checkHidden ? "" : ui.checkbox.label;
+  state.checked = state.checkHidden ? false : ui.checkbox.checked;
+  // TabModalPrompts don't have an infoIcon
+  state.iconClass = ui.infoIcon ? ui.infoIcon.className : null;
+  state.textValue = ui.loginTextbox.value;
+  state.passValue = ui.password1Textbox.value;
+
+  state.butt0Label = ui.button0.label;
+  state.butt1Label = ui.button1.label;
+  state.butt2Label = ui.button2.label;
+
+  state.butt0Disabled = ui.button0.disabled;
+  state.butt1Disabled = ui.button1.disabled;
+  state.butt2Disabled = ui.button2.disabled;
+
+  function isDefaultButton(b) {
+    return b.hasAttribute("default") && b.getAttribute("default") == "true";
+  }
+  state.defButton0 = isDefaultButton(ui.button0);
+  state.defButton1 = isDefaultButton(ui.button1);
+  state.defButton2 = isDefaultButton(ui.button2);
+
+  let e = Services.focus.focusedElement;
+
+  if (e == null) {
+    state.focused = null;
+  } else if (ui.button0.isSameNode(e)) {
+    state.focused = "button0";
+  } else if (ui.button1.isSameNode(e)) {
+    state.focused = "button1";
+  } else if (ui.button2.isSameNode(e)) {
+    state.focused = "button2";
+  } else if (e.isSameNode(ui.loginTextbox)) {
+    state.focused = "textField";
+  } else if (e.isSameNode(ui.password1Textbox)) {
+    state.focused = "passField";
+  } else if (ui.infoBody.isSameNode(e)) {
+    state.focused = "infoBody";
+  } else {
+    state.focused =
+      "ERROR: unexpected element focused: " + (e ? e.localName : "<null>");
+  }
+
+  let treeOwner =
+    ui.prompt && ui.prompt.docShell && ui.prompt.docShell.treeOwner;
+  if (treeOwner && treeOwner.QueryInterface(Ci.nsIInterfaceRequestor)) {
+    // Check that the dialog is modal, chrome and dependent;
+    // We can't just check window.opener because that'll be
+    // a content window, which therefore isn't exposed (it'll lie and
+    // be null).
+    let flags = treeOwner.getInterface(Ci.nsIAppWindow).chromeFlags;
+    state.chrome = (flags & Ci.nsIWebBrowserChrome.CHROME_OPENAS_CHROME) != 0;
+    state.dialog = (flags & Ci.nsIWebBrowserChrome.CHROME_OPENAS_DIALOG) != 0;
+    state.chromeDependent =
+      (flags & Ci.nsIWebBrowserChrome.CHROME_DEPENDENT) != 0;
+    let wbc = treeOwner.getInterface(Ci.nsIWebBrowserChrome);
+    state.isWindowModal = wbc.isWindowModal();
+  }
+
+  // Check the dialog is a common dialog document and has been embedded.
+  let isEmbedded = !!ui.prompt?.docShell?.chromeEventHandler;
+  let isCommonDialogDoc =
+    getDialogDoc()?.location.href.includes("commonDialog.xhtml");
+  state.isSubDialogPrompt = isCommonDialogDoc && isEmbedded;
+  state.showCallerOrigin = ui.prompt.args.showCallerOrigin;
+
+  return state;
+}
+
+function dismissSelect(ui, action) {
+  let dialog = ui.getElementsByTagName("dialog")[0];
+  let listbox = ui.getElementById("list");
+
+  if (action.selectItem) {
+    listbox.selectedIndex = 1;
+  }
+
+  if (action.buttonClick == "ok") {
+    dialog.acceptDialog();
+  } else if (action.buttonClick == "cancel") {
+    dialog.cancelDialog();
+  }
+}
+
+function dismissPrompt(ui, action) {
+  info(`dismissPrompt: action=${JSON.stringify(action)}`);
+  if (action.setCheckbox) {
+    // Annoyingly, the prompt code is driven by oncommand.
+    ui.checkbox.checked = true;
+    ui.checkbox.doCommand();
+  }
+
+  if ("textField" in action) {
+    ui.loginTextbox.setAttribute("value", action.textField);
+  }
+
+  if ("passField" in action) {
+    ui.password1Textbox.setAttribute("value", action.passField);
+  }
+
+  switch (action.buttonClick) {
+    case "ok":
+    case 0:
+      ui.button0.click();
+      break;
+    case "cancel":
+    case 1:
+      ui.button1.click();
+      break;
+    case 2:
+      ui.button2.click();
+      break;
+    case "ESC":
+      // XXX This is assuming tab-modal.
+      let browserWin = Services.wm.getMostRecentWindow("navigator:browser");
+      EventUtils.synthesizeKey("KEY_Escape", {}, browserWin);
+      break;
+    case "pollOK":
+      // Buttons are disabled at the moment, poll until they're reenabled.
+      // Can't use setInterval here, because the window's in a modal state
+      // and thus DOM events are suppressed.
+      let interval = setInterval(() => {
+        if (ui.button0.disabled) {
+          return;
+        }
+        ui.button0.click();
+        clearInterval(interval);
+      }, 100);
+      break;
+    case "none":
+      break;
+
+    default:
+      throw new Error("dismissPrompt action listed unknown button.");
+  }
+}
+
+function getDialogDoc() {
+  // Trudge through all the open windows, until we find the one
+  // that has either commonDialog.xhtml or selectDialog.xhtml loaded.
+  // var enumerator = Services.wm.getEnumerator("navigator:browser");
+  for (let { docShell } of Services.wm.getEnumerator(null)) {
+    var containedDocShells = docShell.getAllDocShellsInSubtree(
+      docShell.typeChrome,
+      docShell.ENUMERATE_FORWARDS
+    );
+    for (let childDocShell of containedDocShells) {
+      // Get the corresponding document for this docshell
+      // We don't want it if it's not done loading.
+      if (childDocShell.busyFlags != Ci.nsIDocShell.BUSY_FLAGS_NONE) {
+        continue;
+      }
+      var childDoc = childDocShell.contentViewer.DOMDocument;
+
+      if (
+        childDoc.location.href !=
+          "chrome://global/content/commonDialog.xhtml" &&
+        childDoc.location.href != "chrome://global/content/selectDialog.xhtml"
+      ) {
+        continue;
+      }
+
+      // We're expecting the dialog to be focused. If it's not yet, try later.
+      // (In particular, this is needed on Linux to reliably check focused elements.)
+      if (Services.focus.focusedWindow != childDoc.defaultView) {
+        continue;
+      }
+
+      return childDoc;
+    }
+  }
+
+  return null;
+}
diff --git a/toolkit/components/prompts/test/mochitest.ini b/toolkit/components/prompts/test/mochitest.ini
new file mode 100644
index 0000000000..9334a9bdb4
--- /dev/null
+++ b/toolkit/components/prompts/test/mochitest.ini
@@ -0,0 +1,19 @@
+[DEFAULT]
+support-files =
+  ../../passwordmgr/test/authenticate.sjs
+  bug619644_inner.html
+  bug625187_iframe.html
+  prompt_common.js
+  chromeScript.js
+
+[test_bug619644.html]
+skip-if = toolkit == 'android' # No tab prompts on android
+[test_bug620145.html]
+skip-if = toolkit == 'android' #TIMED_OUT
+[test_subresources_prompts.html]
+skip-if =
+  toolkit == 'android' || verify
+  http3
+fail-if = xorigin
+[test_dom_prompts.html]
+skip-if = toolkit == 'android' #android: bug 1267092
diff --git a/toolkit/components/prompts/test/prompt_common.js b/toolkit/components/prompts/test/prompt_common.js
new file mode 100644
index 0000000000..4b3a2262aa
--- /dev/null
+++ b/toolkit/components/prompts/test/prompt_common.js
@@ -0,0 +1,445 @@
+const { Cc, Ci, Cu: ChromeUtils } = SpecialPowers;
+
+/**
+ * Converts a property bag to object.
+ * @param {nsIPropertyBag} bag - The property bag to convert
+ * @returns {Object} - The object representation of the nsIPropertyBag
+ */
+function propBagToObject(bag) {
+  if (!(bag instanceof Ci.nsIPropertyBag)) {
+    throw new TypeError("Not a property bag");
+  }
+  let result = {};
+  for (let { name, value } of bag.enumerator) {
+    result[name] = value;
+  }
+  return result;
+}
+
+var modalType;
+var tabSubDialogsEnabled = SpecialPowers.Services.prefs.getBoolPref(
+  "prompts.tabChromePromptSubDialog",
+  false
+);
+var contentSubDialogsEnabled = SpecialPowers.Services.prefs.getBoolPref(
+  "prompts.contentPromptSubDialog",
+  false
+);
+var isSelectDialog = false;
+var isOSX = "nsILocalFileMac" in SpecialPowers.Ci;
+var isE10S = SpecialPowers.Services.appinfo.processType == 2;
+
+var gChromeScript = SpecialPowers.loadChromeScript(
+  SimpleTest.getTestFileURL("chromeScript.js")
+);
+SimpleTest.registerCleanupFunction(() => gChromeScript.destroy());
+
+async function runPromptCombinations(window, testFunc) {
+  let util = new PromptTestUtil(window);
+  let run = () => {
+    info(
+      `Running tests (modalType=${modalType}, usePromptService=${util.usePromptService}, useBrowsingContext=${util.useBrowsingContext}, useAsync=${util.useAsync})`
+    );
+    return testFunc(util);
+  };
+
+  // Prompt service with dom window parent only supports window prompts
+  util.usePromptService = true;
+  util.useBrowsingContext = false;
+  util.modalType = Ci.nsIPrompt.MODAL_TYPE_WINDOW;
+  modalType = util.modalType;
+  util.useAsync = false;
+  await run();
+
+  let modalTypes = [
+    Ci.nsIPrompt.MODAL_TYPE_WINDOW,
+    Ci.nsIPrompt.MODAL_TYPE_TAB,
+    Ci.nsIPrompt.MODAL_TYPE_CONTENT,
+  ];
+
+  for (let type of modalTypes) {
+    util.modalType = type;
+    modalType = type;
+
+    // Prompt service with browsing context sync
+    util.usePromptService = true;
+    util.useBrowsingContext = true;
+    util.useAsync = false;
+    await run();
+
+    // Prompt service with browsing context async
+    util.usePromptService = true;
+    util.useBrowsingContext = true;
+    util.useAsync = true;
+    await run();
+
+    // nsIPrompt
+    // modalType is set via nsIWritablePropertyBag (legacy)
+    util.usePromptService = false;
+    util.useBrowsingContext = false;
+    util.useAsync = false;
+    await run();
+  }
+}
+
+class PromptTestUtil {
+  constructor(window) {
+    this.window = window;
+    this.browsingContext =
+      SpecialPowers.wrap(window).windowGlobalChild.browsingContext;
+    this.promptService = SpecialPowers.Services.prompt;
+    this.nsPrompt = Cc["@mozilla.org/prompter;1"]
+      .getService(Ci.nsIPromptFactory)
+      .getPrompt(window, Ci.nsIPrompt);
+
+    this.usePromptService = null;
+    this.useBrowsingContext = null;
+    this.useAsync = null;
+    this.modalType = null;
+  }
+
+  get _prompter() {
+    if (this.usePromptService) {
+      return this.promptService;
+    }
+    return this.nsPrompt;
+  }
+
+  async prompt(funcName, promptArgs) {
+    if (
+      this.useBrowsingContext == null ||
+      this.usePromptService == null ||
+      this.useAsync == null ||
+      this.modalType == null
+    ) {
+      throw new Error("Not initialized");
+    }
+    let args = [];
+    if (this.usePromptService) {
+      if (this.useBrowsingContext) {
+        if (this.useAsync) {
+          funcName = `async${funcName[0].toUpperCase()}${funcName.substring(
+            1
+          )}`;
+        } else {
+          funcName += "BC";
+        }
+        args = [this.browsingContext, this.modalType];
+      } else {
+        args = [this.window];
+      }
+    } else {
+      let bag = this.nsPrompt.QueryInterface(Ci.nsIWritablePropertyBag2);
+      bag.setPropertyAsUint32("modalType", this.modalType);
+    }
+    // Append the prompt arguments
+    args = args.concat(promptArgs);
+
+    let interfaceName = this.usePromptService ? "Services.prompt" : "prompt";
+    ok(
+      this._prompter[funcName],
+      `${interfaceName} should have method ${funcName}.`
+    );
+
+    info(`Calling ${interfaceName}.${funcName}(${args})`);
+    let result = this._prompter[funcName](...args);
+    is(
+      this.useAsync,
+      result != null &&
+        result.constructor != null &&
+        result.constructor.name === "Promise",
+      "If method is async it should return a promise."
+    );
+
+    if (this.useAsync) {
+      let propBag = await result;
+      return propBag && propBagToObject(propBag);
+    }
+    return result;
+  }
+}
+
+function onloadPromiseFor(id) {
+  var iframe = document.getElementById(id);
+  return new Promise(resolve => {
+    iframe.addEventListener(
+      "load",
+      function (e) {
+        resolve(true);
+      },
+      { once: true }
+    );
+  });
+}
+
+/**
+ * Take an action on the next prompt that appears without checking the state in advance.
+ * This is useful when the action doesn't depend on which prompt is shown and you
+ * are expecting multiple prompts at once in an indeterminate order.
+ * If you know the state of the prompt you expect you should use `handlePrompt` instead.
+ * @param {object} action defining how to handle the prompt
+ * @returns {Promise} resolving with the prompt state.
+ */
+function handlePromptWithoutChecks(action) {
+  return new Promise(resolve => {
+    gChromeScript.addMessageListener("promptHandled", function handled(msg) {
+      gChromeScript.removeMessageListener("promptHandled", handled);
+      resolve(msg.promptState);
+    });
+    gChromeScript.sendAsyncMessage("handlePrompt", { action, modalType });
+  });
+}
+
+async function handlePrompt(state, action) {
+  let actualState = await handlePromptWithoutChecks(action);
+  checkPromptState(actualState, state);
+}
+
+function checkPromptState(promptState, expectedState) {
+  info(`checkPromptState: Expected: ${expectedState.msg}`);
+  // XXX check title? OS X has title in content
+  is(promptState.msg, expectedState.msg, "Checking expected message");
+
+  let isOldContentPrompt =
+    !promptState.isSubDialogPrompt &&
+    modalType === Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+  if (isOldContentPrompt && !promptState.showCallerOrigin) {
+    ok(
+      promptState.titleHidden,
+      "The title should be hidden for content prompts opened with tab modal prompt."
+    );
+  } else if (
+    isOSX ||
+    promptState.isSubDialogPrompt ||
+    promptState.showCallerOrigin
+  ) {
+    ok(
+      !promptState.titleHidden,
+      "Checking title always visible on OS X or when opened with common dialog"
+    );
+  } else {
+    is(
+      promptState.titleHidden,
+      expectedState.titleHidden,
+      "Checking title visibility"
+    );
+  }
+  is(
+    promptState.textHidden,
+    expectedState.textHidden,
+    "Checking textbox visibility"
+  );
+  is(
+    promptState.passHidden,
+    expectedState.passHidden,
+    "Checking passbox visibility"
+  );
+  is(
+    promptState.checkHidden,
+    expectedState.checkHidden,
+    "Checking checkbox visibility"
+  );
+  is(promptState.checkMsg, expectedState.checkMsg, "Checking checkbox label");
+  is(promptState.checked, expectedState.checked, "Checking checkbox checked");
+  if (
+    modalType === Ci.nsIPrompt.MODAL_TYPE_WINDOW ||
+    (modalType === Ci.nsIPrompt.MODAL_TYPE_TAB && tabSubDialogsEnabled)
+  ) {
+    is(
+      promptState.iconClass,
+      expectedState.iconClass,
+      "Checking expected icon CSS class"
+    );
+  }
+  is(promptState.textValue, expectedState.textValue, "Checking textbox value");
+  is(promptState.passValue, expectedState.passValue, "Checking passbox value");
+
+  if (expectedState.butt0Label) {
+    is(
+      promptState.butt0Label,
+      expectedState.butt0Label,
+      "Checking accept-button label"
+    );
+  }
+  if (expectedState.butt1Label) {
+    is(
+      promptState.butt1Label,
+      expectedState.butt1Label,
+      "Checking cancel-button label"
+    );
+  }
+  if (expectedState.butt2Label) {
+    is(
+      promptState.butt2Label,
+      expectedState.butt2Label,
+      "Checking extra1-button label"
+    );
+  }
+
+  // For prompts with a time-delay button.
+  if (expectedState.butt0Disabled) {
+    is(promptState.butt0Disabled, true, "Checking accept-button is disabled");
+    is(
+      promptState.butt1Disabled,
+      false,
+      "Checking cancel-button isn't disabled"
+    );
+  }
+
+  is(
+    promptState.defButton0,
+    expectedState.defButton == "button0",
+    "checking button0 default"
+  );
+  is(
+    promptState.defButton1,
+    expectedState.defButton == "button1",
+    "checking button1 default"
+  );
+  is(
+    promptState.defButton2,
+    expectedState.defButton == "button2",
+    "checking button2 default"
+  );
+
+  if (
+    isOSX &&
+    expectedState.focused &&
+    expectedState.focused.startsWith("button") &&
+    !promptState.infoRowHidden
+  ) {
+    is(
+      promptState.focused,
+      "infoBody",
+      "buttons don't focus on OS X, but infoBody does instead"
+    );
+  } else {
+    is(promptState.focused, expectedState.focused, "Checking focused element");
+  }
+
+  if (expectedState.hasOwnProperty("chrome")) {
+    is(
+      promptState.chrome,
+      expectedState.chrome,
+      "Dialog should be opened as chrome"
+    );
+  }
+  if (expectedState.hasOwnProperty("dialog")) {
+    is(
+      promptState.dialog,
+      expectedState.dialog,
+      "Dialog should be opened as a dialog"
+    );
+  }
+  if (expectedState.hasOwnProperty("chromeDependent")) {
+    is(
+      promptState.chromeDependent,
+      expectedState.chromeDependent,
+      "Dialog should be opened as dependent"
+    );
+  }
+  if (expectedState.hasOwnProperty("isWindowModal")) {
+    is(
+      promptState.isWindowModal,
+      expectedState.isWindowModal,
+      "Dialog should be modal"
+    );
+  }
+}
+
+function checkEchoedAuthInfo(expectedState, browsingContext) {
+  return SpecialPowers.spawn(
+    browsingContext,
+    [expectedState.user, expectedState.pass],
+    (expectedUser, expectedPass) => {
+      let doc = this.content.document;
+
+      // The server echos back the HTTP auth info it received.
+      let username = doc.getElementById("user").textContent;
+      let password = doc.getElementById("pass").textContent;
+      let authok = doc.getElementById("ok").textContent;
+
+      Assert.equal(authok, "PASS", "Checking for successful authentication");
+      Assert.equal(username, expectedUser, "Checking for echoed username");
+      Assert.equal(password, expectedPass, "Checking for echoed password");
+    }
+  );
+}
+
+/**
+ * Create a Proxy to relay method calls on an nsIAuthPrompt[2] prompter to a chrome script which can
+ * perform the calls in the parent. Out and inout params will be copied back from the parent to
+ * content.
+ *
+ * @param chromeScript The reference to the chrome script that will listen to `proxyPrompter`
+ *                     messages in the parent and call the `methodName` method.
+ *                     The return value from the message handler should be an object with properties:
+ * `rv` - containing the return value of the method call.
+ * `args` - containing the array of arguments passed to the method since out or inout ones could have
+ *          been modified.
+ */
+function PrompterProxy(chromeScript) {
+  return new Proxy(
+    {},
+    {
+      get(target, prop, receiver) {
+        return (...args) => {
+          // Array of indices of out/inout params to copy from the parent back to the caller.
+          let outParams = [];
+
+          switch (prop) {
+            case "prompt": {
+              outParams = [/* result */ 5];
+              break;
+            }
+            case "promptAuth": {
+              outParams = [];
+              break;
+            }
+            case "promptPassword":
+            case "asyncPromptPassword": {
+              outParams = [/* pwd */ 4];
+              break;
+            }
+            case "promptUsernameAndPassword":
+            case "asyncPromptUsernameAndPassword": {
+              outParams = [/* user */ 4, /* pwd */ 5];
+              break;
+            }
+            default: {
+              throw new Error("Unknown nsIAuthPrompt method");
+            }
+          }
+
+          let result;
+          chromeScript
+            .sendQuery("proxyPrompter", {
+              args,
+              methodName: prop,
+            })
+            .then(val => {
+              result = val;
+            });
+          SpecialPowers.Services.tm.spinEventLoopUntil(
+            "Test(prompt_common.js:get)",
+            () => result
+          );
+
+          for (let outParam of outParams) {
+            // Copy the out or inout param value over the original
+            args[outParam].value = result.args[outParam].value;
+          }
+
+          if (prop == "promptAuth") {
+            args[2].username = result.args[2].username;
+            args[2].password = result.args[2].password;
+            args[2].domain = result.args[2].domain;
+          }
+
+          return result.rv;
+        };
+      },
+    }
+  );
+}
diff --git a/toolkit/components/prompts/test/test_bug619644.html b/toolkit/components/prompts/test/test_bug619644.html
new file mode 100644
index 0000000000..2b424c71a6
--- /dev/null
+++ b/toolkit/components/prompts/test/test_bug619644.html
@@ -0,0 +1,74 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=619644
+-->
+<head>
+  <title>Test for Bug 619644</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=619644">Mozilla Bug 619644</a>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+// This is a little yucky, but it works
+// The contents of bug619644_inner.html
+const expectedFinalDoc =
+"<head><\/head><body><p>Original content<\/p>\n<script>\n    window.opener.postMessage(\"\", \"*\");\n    confirm(\"Message\");\n    document.write(\"Extra content\");\n    window.opener.postMessage(document.documentElement.innerHTML, \"*\");\n<\/script>Extra content<\/body>";
+
+inittest();
+
+var promptDone;
+
+function inittest() {
+  window.addEventListener("message", runtest);
+  window.open("bug619644_inner.html", "619644");
+
+  SimpleTest.waitForExplicitFinish();
+}
+
+function runtest(e) {
+  modalType = Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+  window.removeEventListener("message", runtest);
+  window.addEventListener("message", checktest);
+
+  let state = {
+      msg: "Message",
+      iconClass: "question-icon",
+      titleHidden: true,
+      textHidden: true,
+      passHidden: true,
+      checkHidden: true,
+      textValue: "",
+      passValue: "",
+      checkMsg: "",
+      checked: false,
+      focused: "button0",
+      defButton: "button0",
+  };
+  let action = {
+      buttonClick: "ESC",
+  };
+
+  promptDone = handlePrompt(state, action);
+}
+
+function checktest(e) {
+  is(e.data, expectedFinalDoc, "ESC press should not abort document load");
+  e.source.close();
+  promptDone.then(endtest);
+}
+
+function endtest() {
+  info("Ending test");
+  SimpleTest.finish();
+}
+</script>
+</pre>
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/test_bug620145.html b/toolkit/components/prompts/test/test_bug620145.html
new file mode 100644
index 0000000000..3894a528ae
--- /dev/null
+++ b/toolkit/components/prompts/test/test_bug620145.html
@@ -0,0 +1,96 @@
+<html>
+<head>
+  <title>Test for Bug 620145</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=620145">Mozilla Bug 620145</a>
+<pre id="test">
+</pre>
+
+<div id="text" style="max-width: 100px" onmouseup="openAlert()">
+  This is a short piece of text used for testing that mouse selecting is
+  stopped when an alert appears.
+</div>
+<div id="text2" style="max-width: 100px">
+  This is another short piece of text used for testing that mouse selecting is
+  stopped when an alert appears.
+</div>
+<button id="button" onmouseup="openAlert()">Button</button>
+
+<script class="testbody" type="text/javascript">
+
+function openAlert() {
+  info("opening alert...");
+  alert("hello!");
+  info("...alert done.");
+}
+
+add_task(async function runTest() {
+  var state, action;
+  // The <button> in this test's HTML opens a prompt when clicked.
+  // Here we send the events to simulate clicking it.
+  modalType = Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+  state = {
+    msg: "hello!",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  let promptDone = handlePrompt(state, action);
+
+  var button = $("button");
+  dispatchMouseEvent(button, "mousedown");
+  dispatchMouseEvent(button, "mouseup");
+  // alert appears at this point, to be closed by the chrome script.
+
+  await promptDone;
+  checkSelection();
+
+  // using same state and action.
+  promptDone = handlePrompt(state, action);
+
+  var text = $("text");
+  dispatchMouseEvent(text, "mousedown");
+  dispatchMouseEvent(text, "mouseup");
+  // alert appears at this point, to be closed by the chrome script.
+
+  await promptDone;
+  checkSelection();
+});
+
+function dispatchMouseEvent(target, type) {
+  var win = target.ownerDocument.defaultView;
+  let e = document.createEvent("MouseEvent");
+  e.initEvent(type, false, false, win, 0, 1, 1, 1, 1,
+              false, false, false, false, 0, null);
+  var utils = SpecialPowers.getDOMWindowUtils(win);
+  utils.dispatchDOMEventViaPresShellForTesting(target, e);
+  ok(true, type + " sent to " + target.id);
+}
+
+function checkSelection() {
+  synthesizeMouse($("text"), 25, 55, { type: "mousemove" });
+  is(window.getSelection().toString(), "", "selection not made");
+}
+</script>
+
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/test_dom_prompts.html b/toolkit/components/prompts/test/test_dom_prompts.html
new file mode 100644
index 0000000000..95595b8df2
--- /dev/null
+++ b/toolkit/components/prompts/test/test_dom_prompts.html
@@ -0,0 +1,207 @@
+<html>
+<head>
+  <title>Test for DOM prompts</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<pre id="test">
+</pre>
+
+<script class="testbody" type="text/javascript">
+var rv;
+var state, action;
+modalType = Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+add_task(async function test_alert_ok() {
+    info("Starting test: Alert");
+    state = {
+        msg: "This is the alert text.",
+        iconClass: "alert-icon",
+        titleHidden: true,
+        textHidden: true,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "button0",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    alert("This is the alert text.");
+
+    await promptDone;
+});
+
+// bug 861605 made the arguments to alert/confirm optional (prompt already was).
+add_task(async function test_alert_noargs() {
+    info("Starting test: Alert with no args");
+    state = {
+        msg: "",
+        iconClass: "alert-icon",
+        titleHidden: true,
+        textHidden: true,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "button0",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    try {
+        alert();
+        ok(true, "alert() without arguments should not throw!");
+    } catch (e) {
+        ok(false, "alert() without arguments should not throw!");
+    }
+
+    await promptDone;
+});
+
+add_task(async function test_confirm_ok() {
+    info("Starting test: Confirm");
+    state = {
+        msg: "This is the confirm text.",
+        iconClass: "question-icon",
+        titleHidden: true,
+        textHidden: true,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "button0",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    rv = confirm("This is the confirm text.");
+    is(rv, true, "check prompt return value");
+
+    await promptDone;
+});
+
+// bug 861605 made the arguments to alert/confirm optional (prompt already was).
+add_task(async function test_confirm_noargs() {
+    info("Starting test: Confirm with no args");
+    state = {
+        msg: "",
+        iconClass: "question-icon",
+        titleHidden: true,
+        textHidden: true,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "button0",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    try {
+        rv = confirm();
+        ok(true, "confirm() without arguments should not throw!");
+    } catch (e) {
+        ok(false, "confirm() without arguments should not throw!");
+    }
+    is(rv, true, "check prompt return value");
+
+    await promptDone;
+});
+
+
+add_task(async function test_prompt_ok() {
+    info("Starting test: Prompt");
+    state = {
+        msg: "This is the Prompt text.",
+        iconClass: "question-icon",
+        titleHidden: true,
+        textHidden: false,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "textField",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    rv = prompt("This is the Prompt text.");
+    is(rv, "", "check prompt return value");
+
+    await promptDone;
+});
+
+// bug 861605 made the arguments to alert/confirm optional (prompt already was).
+add_task(async function test_prompt_noargs() {
+    info("Starting test: Prompt with no args");
+    state = {
+        msg: "",
+        iconClass: "question-icon",
+        titleHidden: true,
+        textHidden: false,
+        passHidden: true,
+        checkHidden: true,
+        textValue: "",
+        passValue: "",
+        checkMsg: "",
+        checked: false,
+        focused: "textField",
+        defButton: "button0",
+    };
+    action = {
+        buttonClick: "ok",
+    };
+
+    let promptDone = handlePrompt(state, action);
+
+    try {
+        rv = prompt();
+        ok(true, "prompt() without arguments should not throw!");
+    } catch (e) {
+        ok(false, "prompt() without arguments should not throw!");
+    }
+    is(rv, "", "check prompt return value");
+
+    await promptDone;
+});
+
+</script>
+
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/test_modal_prompts.html b/toolkit/components/prompts/test/test_modal_prompts.html
new file mode 100644
index 0000000000..df3438dbba
--- /dev/null
+++ b/toolkit/components/prompts/test/test_modal_prompts.html
@@ -0,0 +1,1311 @@
+
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Modal Prompts Test</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+</head>
+<body>
+Prompter tests: modal prompts
+<p id="display"></p>
+
+<div id="content" style="display: none">
+  <iframe id="iframe"></iframe>
+</div>
+
+<pre id="test">
+<script class="testbody" type="text/javascript">
+/* eslint-disable complexity */
+async function runTests(util) {
+  const { NetUtil } = SpecialPowers.ChromeUtils.import(
+    "resource://gre/modules/NetUtil.jsm"
+  );
+
+  // The ConfirmEx + delay test has slightly different behavior with the focus
+  // fixup rule vs. without.
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.focus.fixup", true]],
+  });
+
+  let state, action, promptDone;
+
+  let checkVal = {};
+  let textVal = {};
+  let passVal = {};
+  let flags;
+  let isOK;
+
+  // =====
+  info("Starting test: Alert");
+  state = {
+    msg: "This is the alert text.",
+    title: "TestTitle",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = ["TestTitle", "This is the alert text."];
+  await util.prompt("alert", promptArgs);
+
+  await promptDone;
+
+  // =====
+  info("Starting test: AlertCheck (null checkbox label, so it's hidden)");
+  state = {
+    msg: "This is the alertCheck text.",
+    title: "TestTitle",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = [
+    "TestTitle",
+    "This is the alertCheck text.",
+    null,
+    util.useAsync ? false : {},
+  ];
+  util.prompt("alertCheck", promptArgs);
+
+  await promptDone;
+
+  // =====
+  info("Starting test: AlertCheck");
+  state = {
+    msg: "This is the alertCheck text.",
+    title: "TestTitle",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the alertCheck text.",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  let result = await util.prompt("alertCheck", promptArgs);
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "checkbox was checked"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Confirm (ok)");
+  state = {
+    msg: "This is the confirm text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = ["TestTitle", "This is the confirm text."];
+  result = await util.prompt("confirm", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Confirm (cancel)");
+  state = {
+    msg: "This is the confirm text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = ["TestTitle", "This is the confirm text."];
+  result = await util.prompt("confirm", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmCheck (ok, null checkbox label)");
+  state = {
+    msg: "This is the confirmCheck text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmCheck text.",
+    null,
+    util.useAsync ? false : {},
+  ];
+  result = await util.prompt("confirmCheck", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmCheck (cancel, null checkbox label)");
+  state = {
+    msg: "This is the confirmCheck text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmCheck text.",
+    null,
+    util.useAsync ? false : {},
+  ];
+  result = await util.prompt("confirmCheck", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmCheck (ok)");
+  state = {
+    msg: "This is the confirmCheck text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmCheck text.",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("confirmCheck", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmCheck (cancel)");
+  state = {
+    msg: "This is the confirmCheck text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmCheck text.",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("confirmCheck", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (ok, no default text)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "bacon",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "";
+  promptArgs = ["TestTitle", "This is the prompt text.", util.useAsync ? textVal.value : textVal , null, util.useAsync ? false : {}];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "bacon",
+    "checking expected text value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (ok, default text)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "kittens",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "kittens";
+  promptArgs = ["TestTitle", "This is the prompt text.", util.useAsync ? textVal.value : textVal, null, util.useAsync ? false : {}];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "kittens",
+    "checking expected text value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (cancel, default text)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "puppies",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "puppies";
+  promptArgs = ["TestTitle", "This is the prompt text.", util.useAsync ? textVal.value : textVal, null, util.useAsync ? false : {}];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "puppies",
+    "checking expected text value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (cancel, default text modified)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "puppies",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+    textField: "bacon",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "puppies";
+  promptArgs = ["TestTitle", "This is the prompt text.", util.useAsync ? textVal.value : textVal, null, util.useAsync ? false : {}];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "puppies",
+    "checking expected text value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (ok, with checkbox)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "tribbles",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "tribbles";
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the prompt text.",
+    util.useAsync ? textVal.value : textVal,
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "tribbles",
+    "checking expected text value"
+  );
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: Prompt (cancel, with checkbox)");
+  state = {
+    msg: "This is the prompt text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "tribbles",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+    setCheckbox: true,
+  };
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "tribbles";
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the prompt text.",
+    util.useAsync ? textVal.value : textVal,
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("prompt", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  is(
+    util.useAsync ? result.value : textVal.value,
+    "tribbles",
+    "checking expected text value"
+  );
+  ok(
+    util.useAsync ? result.checked : !checkVal.value,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  // Just two tests for this, since password manager already tests this extensively.
+  info("Starting test: PromptUsernameAndPassword (ok)");
+  state = {
+    msg: "This is the pUAP text.",
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "usr",
+    passValue: "ssh",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "newusr",
+    passField: "newssh",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "usr";
+  passVal.value = "ssh";
+  promptArgs = [
+    "TestTitle",
+    "This is the pUAP text.",
+    util.useAsync ? textVal.value : textVal,
+    util.useAsync ? passVal.value : passVal
+  ];
+  result = await util.prompt("promptUsernameAndPassword", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.user : textVal.value,
+    "newusr",
+    "checking expected text value"
+  );
+  is(
+    util.useAsync ? result.pass : passVal.value,
+    "newssh",
+    "checking expected pass value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: PromptUsernameAndPassword (cancel)");
+  state = {
+    msg: "This is the pUAP text.",
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "usr",
+    passValue: "ssh",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+    textField: "newusr",
+    passField: "newssh",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  textVal.value = "usr";
+  passVal.value = "ssh";
+  promptArgs = [
+    "TestTitle",
+    "This is the pUAP text.",
+    util.useAsync ? textVal.value : textVal,
+    util.useAsync ? passVal.value : passVal
+  ];
+  result = await util.prompt("promptUsernameAndPassword", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  ok(
+    (util.useAsync && result.user == "newusr") || textVal.value == "usr",
+    "checking expected text value"
+  );
+  ok(
+    (util.useAsync && result.pass == "newpass") || passVal.value == "ssh",
+    "checking expected pass value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: PromptPassword (ok)");
+  state = {
+    msg: "This is the promptPassword text.",
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "ssh",
+    focused: "passField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    passField: "newssh",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  passVal.value = "ssh";
+  promptArgs = [
+    "TestTitle",
+    "This is the promptPassword text.",
+    util.useAsync ? passVal.value : passVal
+  ];
+  result = await util.prompt("promptPassword", promptArgs);
+  is(util.useAsync ? result.ok : result, true, "checked expected retval");
+  is(
+    util.useAsync ? result.pass : passVal.value,
+    "newssh",
+    "checking expected pass value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: PromptPassword (cancel)");
+  state = {
+    msg: "This is the promptPassword text.",
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "ssh",
+    focused: "passField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "cancel",
+    passField: "newssh",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  passVal.value = "ssh";
+  promptArgs = [
+    "TestTitle",
+    "This is the promptPassword text.",
+    util.useAsync ? passVal.value : passVal
+  ];
+  result = await util.prompt("promptPassword", promptArgs);
+  is(util.useAsync ? result.ok : result, false, "checked expected retval");
+  ok(
+    (util.useAsync && result.pass == "newssh") || passVal.value == "ssh",
+    "checking expected pass value"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmEx (ok/cancel, ok)");
+  state = {
+    msg: "This is the confirmEx text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+    butt0Label: "OK",
+    butt1Label: "Cancel",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  flags = Ci.nsIPromptService.STD_OK_CANCEL_BUTTONS;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmEx text.",
+    flags,
+    null,
+    null,
+    null,
+    null,
+    util.useAsync ? false : {},
+  ];
+  result = await util.prompt("confirmEx", promptArgs);
+  is(
+    util.useAsync ? result.buttonNumClicked : result,
+    0,
+    "checked expected button num click"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmEx (yes/no, cancel)");
+  state = {
+    msg: "This is the confirmEx text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+    butt0Label: "Yes",
+    butt1Label: "No",
+  };
+  action = {
+    buttonClick: "cancel",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  flags = Ci.nsIPromptService.STD_YES_NO_BUTTONS;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmEx text.",
+    flags,
+    null,
+    null,
+    null,
+    null,
+    util.useAsync ? false : {},
+  ];
+  result = await util.prompt("confirmEx", promptArgs);
+  is(
+    util.useAsync ? result.buttonNumClicked : result,
+    1,
+    "checked expected button num click"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmEx (buttons from args, checkbox, ok)");
+  state = {
+    msg: "This is the confirmEx text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+    butt0Label: "butt0",
+    butt1Label: "butt1",
+    butt2Label: "butt2",
+  };
+  action = {
+    buttonClick: "ok",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  let b = Ci.nsIPromptService.BUTTON_TITLE_IS_STRING;
+  flags =
+    b * Ci.nsIPromptService.BUTTON_POS_2 +
+    b * Ci.nsIPromptService.BUTTON_POS_1 +
+    b * Ci.nsIPromptService.BUTTON_POS_0;
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmEx text.",
+    flags,
+    "butt0",
+    "butt1",
+    "butt2",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("confirmEx", promptArgs);
+  is(
+    util.useAsync ? result.buttonNumClicked : result,
+    0,
+    "checked expected button num click"
+  );
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmEx (buttons from args, checkbox, cancel)");
+  state = {
+    msg: "This is the confirmEx text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button1", // Default changed!
+    defButton: "button1",
+    butt0Label: "butt0",
+    butt1Label: "butt1",
+    butt2Label: "butt2",
+  };
+  action = {
+    buttonClick: "cancel",
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  b = Ci.nsIPromptService.BUTTON_TITLE_IS_STRING;
+  flags =
+    b * Ci.nsIPromptService.BUTTON_POS_2 +
+    b * Ci.nsIPromptService.BUTTON_POS_1 +
+    b * Ci.nsIPromptService.BUTTON_POS_0;
+  flags ^= Ci.nsIPromptService.BUTTON_POS_1_DEFAULT;
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmEx text.",
+    flags,
+    "butt0",
+    "butt1",
+    "butt2",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("confirmEx", promptArgs);
+  is(
+    util.useAsync ? result.buttonNumClicked : result,
+    1,
+    "checked expected button num click"
+  );
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  info("Starting test: ConfirmEx (buttons from args, checkbox, button3)");
+  state = {
+    msg: "This is the confirmEx text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: false,
+    textValue: "",
+    passValue: "",
+    checkMsg: "Check me out!",
+    checked: false,
+    focused: "button2", // Default changed!
+    defButton: "button2",
+    butt0Label: "butt0",
+    butt1Label: "butt1",
+    butt2Label: "butt2",
+  };
+  action = {
+    buttonClick: 2,
+    setCheckbox: true,
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  b = Ci.nsIPromptService.BUTTON_TITLE_IS_STRING;
+  flags =
+    b * Ci.nsIPromptService.BUTTON_POS_2 +
+    b * Ci.nsIPromptService.BUTTON_POS_1 +
+    b * Ci.nsIPromptService.BUTTON_POS_0;
+  flags ^= Ci.nsIPromptService.BUTTON_POS_2_DEFAULT;
+  checkVal.value = false;
+  promptArgs = [
+    "TestTitle",
+    "This is the confirmEx text.",
+    flags,
+    "butt0",
+    "butt1",
+    "butt2",
+    "Check me out!",
+    util.useAsync ? checkVal.value : checkVal,
+  ];
+  result = await util.prompt("confirmEx", promptArgs);
+  is(
+    util.useAsync ? result.buttonNumClicked : result,
+    2,
+    "checked expected button num click"
+  );
+  is(
+    util.useAsync ? result.checked : checkVal.value,
+    true,
+    "expected checkbox setting"
+  );
+
+  await promptDone;
+
+  // =====
+  // (skipped for E10S and tabmodal tests: window is required)
+  info("Starting test: Alert, no window");
+  state = {
+    msg: "This is the alert text.",
+    title: "TestTitle",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+  if (util.modalType === Ci.nsIPrompt.MODAL_TYPE_WINDOW && !isE10S) {
+    promptDone = handlePrompt(state, action);
+
+    promptArgs = ["TestTitle", "This is the alert text."];
+    await util.prompt("alert", promptArgs);
+
+    await promptDone;
+  }
+
+  // =====
+  // (skipped for tabmodal tests: delay not supported)
+  info("Starting test: ConfirmEx (delay, ok)");
+  state = {
+    msg: "This is the confirmEx delay text.",
+    title: "TestTitle",
+    iconClass: "question-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: null, // Nothing focused until the delay triggers.
+    defButton: "button0",
+    butt0Label: "OK",
+    butt1Label: "Cancel",
+    butt0Disabled: true,
+  };
+
+  if (isOSX) {
+    // OS X doesn't initially focus the button, but rather the infoBody.
+    // The focus stays there even after the button-enable delay has fired.
+    state.focused = "infoBody";
+  }
+
+  action = {
+    buttonClick: "pollOK",
+  };
+  if (util.modalType === Ci.nsIPrompt.MODAL_TYPE_WINDOW) {
+    promptDone = handlePrompt(state, action);
+
+    flags =
+      Ci.nsIPromptService.STD_OK_CANCEL_BUTTONS |
+      Ci.nsIPromptService.BUTTON_DELAY_ENABLE;
+    promptArgs = [
+      "TestTitle",
+      "This is the confirmEx delay text.",
+      flags,
+      null,
+      null,
+      null,
+      null,
+      util.useAsync ? false : {},
+    ];
+    result = await util.prompt("confirmEx", promptArgs);
+    is(
+      util.useAsync ? result.buttonNumClicked : result,
+      0,
+      "checked expected button num click"
+    );
+
+    await promptDone;
+  }
+
+  // promptAuth already tested via password manager but do a few specific things here.
+  var channel = NetUtil.newChannel({
+    uri: "http://example.com",
+    loadUsingSystemPrincipal: true,
+  });
+
+  var level = Ci.nsIAuthPrompt2.LEVEL_NONE;
+  var authinfo = {
+    username: "",
+    password: "",
+    domain: "",
+    flags: Ci.nsIAuthInformation.AUTH_HOST,
+    authenticationScheme: "basic",
+    realm: "",
+  };
+
+  let msg =
+    util.modalType == Ci.nsIPrompt.MODAL_TYPE_TAB
+      ? "This site is asking you to sign in."
+      : "http://example.com is requesting your username and password.";
+  // =====
+  // (promptAuth is only accessible from the prompt service)
+  info("Starting test: promptAuth with empty realm");
+  state = {
+    msg,
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "username",
+    passField: "password",
+  };
+  if (util.usePromptService && !util.useAsync) {
+    promptDone = handlePrompt(state, action);
+
+    promptArgs = [channel, level, authinfo];
+    isOK = await util.prompt("promptAuth", promptArgs);
+    is(isOK, true, "checked expected retval");
+    is(authinfo.username, "username", "checking filled username");
+    is(authinfo.password, "password", "checking filled password");
+
+    await promptDone;
+  }
+
+  // =====
+  // (promptAuth is only accessible from the prompt service)
+  msg =
+    util.modalType == Ci.nsIPrompt.MODAL_TYPE_TAB
+      ? "This site is asking you to sign in."
+      : "http://example.com is requesting your username and password. The site " +
+        "says: \u201cabcdefghi abcdefghi abcdefghi abcdefghi abcdefghi abcdefghi abcdefghi " +
+        "abcdefghi abcdefghi abcdefghi abcdefghi abcdefghi abcdefghi abcdefghi " +
+        "abcdefghi \u2026\u201d";
+
+  info("Starting test: promptAuth with long realm");
+  state = {
+    msg,
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "username",
+    passField: "password",
+  };
+  if (util.usePromptService && !util.useAsync) {
+    promptDone = handlePrompt(state, action);
+
+    var longString = "";
+    for (var i = 0; i < 20; i++) longString += "abcdefghi "; // 200 chars long
+    authinfo.realm = longString;
+    authinfo.username = "";
+    authinfo.password = "";
+    promptArgs = [channel, level, authinfo];
+    isOK = await util.prompt("promptAuth", promptArgs);
+    is(isOK, true, "checked expected retval");
+    is(authinfo.username, "username", "checking filled username");
+    is(authinfo.password, "password", "checking filled password");
+
+    await promptDone;
+  }
+
+  msg =
+    util.modalType == Ci.nsIPrompt.MODAL_TYPE_TAB
+      ? ("This site is asking you to sign in. Warning: Your login information " +
+        "will be shared with example.com, not the website you are currently visiting.")
+      : ("http://example.com is requesting your username and password. " +
+        "WARNING: Your password will not be sent to the website you are currently visiting!");
+  info("Starting test: promptAuth for a cross-origin and a empty realm");
+  authinfo = {
+    username: "",
+    password: "",
+    domain: "",
+    flags:
+      Ci.nsIAuthInformation.AUTH_HOST |
+      Ci.nsIAuthInformation.CROSS_ORIGIN_SUB_RESOURCE,
+    authenticationScheme: "basic",
+    realm: "",
+  };
+  state = {
+    msg,
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "username",
+    passField: "password",
+  };
+  if (util.usePromptService && !util.useAsync) {
+    promptDone = handlePrompt(state, action);
+    promptArgs = [channel, level, authinfo];
+    isOK = await util.prompt("promptAuth", promptArgs);
+    is(isOK, true, "checked expected retval");
+    is(authinfo.username, "username", "checking filled username");
+    is(authinfo.password, "password", "checking filled password");
+
+    await promptDone;
+  }
+
+  info("Starting test: promptAuth for a cross-origin with realm");
+  authinfo = {
+    username: "",
+    password: "",
+    domain: "",
+    flags:
+      Ci.nsIAuthInformation.AUTH_HOST |
+      Ci.nsIAuthInformation.CROSS_ORIGIN_SUB_RESOURCE,
+    authenticationScheme: "basic",
+    realm: "Something!!!",
+  };
+  state = {
+    msg, // Same as previous test, see above.
+    title: "TestTitle",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    textValue: "",
+    passValue: "",
+    focused: "textField",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+    textField: "username",
+    passField: "password",
+  };
+  if (util.usePromptService && !util.useAsync) {
+    promptDone = handlePrompt(state, action);
+
+    promptArgs = [channel, level, authinfo];
+    isOK = await util.prompt("promptAuth", promptArgs);
+    is(isOK, true, "checked expected retval");
+    is(authinfo.username, "username", "checking filled username");
+    is(authinfo.password, "password", "checking filled password");
+
+    await promptDone;
+  }
+}
+
+let promptArgs;
+
+add_task(async function runPromptTests() {
+  await runPromptCombinations(window, runTests);
+});
+</script>
+</pre>
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/test_modal_select.html b/toolkit/components/prompts/test/test_modal_select.html
new file mode 100644
index 0000000000..27688cf329
--- /dev/null
+++ b/toolkit/components/prompts/test/test_modal_select.html
@@ -0,0 +1,138 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Modal Prompts Test</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+</head>
+<body>
+Prompter tests: modal prompts
+<p id="display"></p>
+
+<div id="content" style="display: none">
+  <iframe id="iframe"></iframe>
+</div>
+
+<pre id="test">
+<script class="testbody" type="text/javascript">
+function checkPromptState(promptState, expectedState) {
+    // XXX check title? OS X has title in content
+    // XXX check focused element
+    // XXX check button labels?
+
+    is(promptState.msg, expectedState.msg, "Checking expected message");
+
+    // Compare listbox contents
+    is(promptState.items.length, expectedState.items.length, "Checking listbox length");
+
+    if (promptState.items.length)
+      is(promptState.selectedIndex, 0, "Checking selected index");
+
+    for (let i = 0; i < promptState.items; i++) {
+        is(promptState.items[i], expectedState.items[i], "Checking list item #" + i);
+    }
+}
+
+let selectVal = {};
+let isOK;
+
+function handlePrompt(state, action) {
+  return new Promise(resolve => {
+    gChromeScript.addMessageListener("promptHandled", function handled(msg) {
+      gChromeScript.removeMessageListener("promptHandled", handled);
+      checkPromptState(msg.promptState, state);
+      resolve(true);
+    });
+    gChromeScript.sendAsyncMessage("handlePrompt", { action, isSelect: true});
+  });
+}
+
+async function runTests(util) {
+    // Select prompt does not support tab or content prompts yet. See Bug 1622817.
+    if(util.modalType != Ci.nsIPrompt.MODAL_TYPE_WINDOW) {
+        info('Skipping modal type for select prompt...');
+        return;
+    }
+
+    // Empty list
+    info("Starting test: Select (0 items, ok)");
+    let state = {
+        msg: "This is the select text.",
+        title: "TestTitle",
+        items: [],
+    };
+    let action = {
+        buttonClick: "ok",
+    };
+    let promptDone = handlePrompt(state, action);
+    let items = [];
+    selectVal.value = null; // outparam, just making sure.
+    let result =  await util.prompt("select", ["TestTitle", "This is the select text.", items, util.useAsync ? false : selectVal]);
+    is(util.useAsync ? result.ok : result, true, "checked expected retval");
+    is(util.useAsync ? result.selected : selectVal.value, -1, "checking selected index");
+    await promptDone;
+
+    // ok
+    info("Starting test: Select (3 items, ok)");
+    state = {
+        msg: "This is the select text.",
+        title: "TestTitle",
+        items: ["one", "two", "three"],
+    };
+    action = {
+        buttonClick: "ok",
+    };
+    promptDone = handlePrompt(state, action);
+    items = ["one", "two", "three"];
+    selectVal.value = null; // outparam, just making sure.
+    result = await util.prompt("select", ["TestTitle", "This is the select text.", items, util.useAsync ? false : selectVal]);
+    is(util.useAsync ? result.ok : result, true, "checked expected retval");
+    is(util.useAsync ? result.selected : selectVal.value, 0, "checking selected index");
+    await promptDone;
+
+    // select item
+    info("Starting test: Select (3 items, selection changed, ok)");
+    state = {
+        msg: "This is the select text.",
+        title: "TestTitle",
+        items: ["one", "two", "three"],
+    };
+    action = {
+        buttonClick: "ok",
+        selectItem: 1,
+    };
+    promptDone = handlePrompt(state, action);
+    items = ["one", "two", "three"];
+    selectVal.value = null; // outparam, just making sure.
+    result = await util.prompt("select", ["TestTitle", "This is the select text.", items,  util.useAsync ? false : selectVal]);
+    is(util.useAsync ? result.ok : result, true, "checked expected retval");
+    is(util.useAsync ? result.selected : selectVal.value, 1, "checking selected index");
+    await promptDone;
+
+    // cancel prompt
+    info("Starting test: Select (3 items, cancel)");
+    state = {
+        msg: "This is the select text.",
+        title: "TestTitle",
+        items: ["one", "two", "three"],
+    };
+    action = {
+        buttonClick: "cancel",
+    };
+    promptDone = handlePrompt(state, action);
+    items = ["one", "two", "three"];
+    selectVal.value = null; // outparam, just making sure.
+    result = await util.prompt("select", ["TestTitle", "This is the select text.", items,  util.useAsync ? false : selectVal]);
+    is(util.useAsync ? result.ok : result, false, "checked expected retval");
+    ok(util.useAsync && result.selected == -1 || selectVal.value == 0, "checking selected index");
+    await promptDone;
+}
+
+add_task(async function runPromptTests() {
+    await runPromptCombinations(window, runTests);
+});
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/toolkit/components/prompts/test/test_subresources_prompts.html b/toolkit/components/prompts/test/test_subresources_prompts.html
new file mode 100644
index 0000000000..b71ad0694e
--- /dev/null
+++ b/toolkit/components/prompts/test/test_subresources_prompts.html
@@ -0,0 +1,200 @@
+<html>
+<head>
+  <title>Test subresources prompts (Bug 625187 and bug 1230462)</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script type="text/javascript" src="prompt_common.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+<!--
+   - Any copyright is dedicated to the Public Domain.
+   - http://creativecommons.org/publicdomain/zero/1.0/
+   -
+   - Contributor(s):
+   -   Mihai Sucan <mihai.sucan@gmail.com>
+   -->
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=625187">Mozilla Bug 625187</a>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1230462">Mozilla Bug 1230462</a>
+
+<p><button id="topbutton" onclick="alert('hello world')">Button</button></p>
+
+<iframe id="iframe_diff_origin" src="http://example.com/tests/toolkit/components/prompts/test/bug625187_iframe.html"></iframe>
+
+<iframe id="iframe_same_origin" src="bug625187_iframe.html"></iframe>
+
+<iframe id="iframe_prompt"></iframe>
+
+<pre id="test"></pre>
+
+<script class="testbody" type="text/javascript">
+var iframe1Loaded = onloadPromiseFor("iframe_diff_origin");
+var iframe2Loaded = onloadPromiseFor("iframe_same_origin");
+var iframe_prompt = document.getElementById("iframe_prompt");
+
+// Depending on pref state we either show auth prompts as windows or on tab level.
+let authPromptModalType = SpecialPowers.Services.prefs.getIntPref(
+  "prompts.modalType.httpAuth"
+);
+
+add_task(async function runTest() {
+  modalType = Ci.nsIPrompt.MODAL_TYPE_CONTENT;
+
+  info("Ensuring iframe1 has loaded...");
+  await iframe1Loaded;
+  info("Ensuring iframe2 has loaded...");
+  await iframe2Loaded;
+  let state, action;
+
+  state = {
+    msg: "hello world",
+    iconClass: "alert-icon",
+    titleHidden: true,
+    textHidden: true,
+    passHidden: true,
+    checkHidden: true,
+    textValue: "",
+    passValue: "",
+    checkMsg: "",
+    checked: false,
+    focused: "button0",
+    defButton: "button0",
+  };
+  action = {
+    buttonClick: "ok",
+  };
+
+  let promptDone = handlePrompt(state, action);
+
+  await SpecialPowers.spawn(window, ["topbutton", "click"], dispatchMouseEvent);
+
+  await promptDone;
+
+  // mostly reusing same state/action
+  state.titleHidden = false;
+  state.msg = "hello world 2";
+  promptDone = handlePrompt(state, action);
+
+  var iframe = document.getElementById("iframe_diff_origin");
+  await SpecialPowers.spawn(iframe.contentWindow, ["btn1", "click"], dispatchMouseEvent);
+
+  await promptDone;
+
+  // mostly reusing same state/action
+  state.titleHidden = true;
+  state.msg = "hello world 2";
+  promptDone = handlePrompt(state, action);
+
+  iframe = document.getElementById("iframe_same_origin");
+  await SpecialPowers.spawn(iframe.contentWindow, ["btn1", "click"], dispatchMouseEvent);
+
+  await promptDone;
+
+  // mostly reusing same state/action
+  state.msg = "hello world 3";
+  promptDone = handlePrompt(state, action);
+  await SpecialPowers.spawn(iframe.contentWindow, ["btn2", "click"], dispatchMouseEvent);
+
+  await promptDone;
+});
+
+add_task(async function runTestAuth() {
+  // Following tests check prompt message for a cross-origin and not
+  // cross-origin subresources load
+
+  // Let prompt_common know what kind of modal type is enabled for auth prompts.
+  modalType = authPromptModalType;
+
+  let state, action;
+
+  state = {
+    msg: "This site is asking you to sign in.",
+    title: "Authentication Required",
+    textValue: "",
+    passValue: "",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+
+  action = {
+    buttonClick: "ok",
+    setCheckbox: false,
+    textField: "mochiuser1",
+    passField: "mochipass1",
+  };
+
+  let promptDone = handlePrompt(state, action);
+
+  var iframe3Loaded = onloadPromiseFor("iframe_prompt");
+  iframe_prompt.src = "authenticate.sjs?user=mochiuser1&pass=mochipass1";
+  await promptDone;
+  await iframe3Loaded;
+  await checkEchoedAuthInfo({user: "mochiuser1", pass: "mochipass1"},
+                            iframe_prompt);
+
+  // Cross-origin subresourse test.
+  state = {
+    msg: "This site is asking you to sign in. Warning: Your login information " +
+      "will be shared with example.com, not the website you are currently visiting.",
+    title: "Authentication Required",
+    textValue: "",
+    passValue: "",
+    iconClass: "authentication-icon question-icon",
+    titleHidden: true,
+    textHidden: false,
+    passHidden: false,
+    checkHidden: true,
+    checkMsg: "",
+    checked: false,
+    focused: "textField",
+    defButton: "button0",
+  };
+
+  action = {
+    buttonClick: "ok",
+    setCheckbox: false,
+    textField: "mochiuser2",
+    passField: "mochipass2",
+  };
+
+  promptDone = handlePrompt(state, action);
+
+  iframe3Loaded = onloadPromiseFor("iframe_prompt");
+  iframe_prompt.src = "http://example.com/tests/toolkit/components/prompts/test/authenticate.sjs?user=mochiuser2&pass=mochipass2&realm=mochitest";
+  await promptDone;
+  await iframe3Loaded;
+  await checkEchoedAuthInfo({user: "mochiuser2", pass: "mochipass2"},
+                            iframe_prompt);
+});
+
+/**
+ * Function to be passed to SpecialPowers.spawn that dispatches a MouseEvent
+ * of a certain type to some element in a subframe.
+ *
+ * @param {String} targetID The ID of the element that will have the event
+ * dispatched on.
+ * @param {String} type The type of MouseEvent.
+ * @returns Promise
+ * @resolves Once the event has been dispatched.
+ */
+async function dispatchMouseEvent(targetID, type) {
+  /* eslint-disable no-undef */
+  let document = content.document;
+  let element = document.getElementById(targetID);
+  let event = document.createEvent("MouseEvent");
+  event.initEvent(type, false, false, content, 0, 1, 1, 1, 1,
+                  false, false, false, false, 0, null);
+  content.windowUtils.dispatchDOMEventViaPresShellForTesting(element, event);
+  /* eslint-enable no-undef */
+}
+</script>
+</body>
+</html>