10 files changed, 2233 insertions, 0 deletions
diff --git a/remote/cdp/domains/parent/Browser.sys.mjs b/remote/cdp/domains/parent/Browser.sys.mjs
new file mode 100644
index 0000000000..ecf93d4d8d
--- /dev/null
+++ b/remote/cdp/domains/parent/Browser.sys.mjs
@@ -0,0 +1,40 @@
+/* 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 { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+export class Browser extends Domain {
+  getVersion() {
+    const { isHeadless } = Cc["@mozilla.org/gfx/info;1"].getService(
+      Ci.nsIGfxInfo
+    );
+    const { userAgent } = Cc[
+      "@mozilla.org/network/protocol;1?name=http"
+    ].getService(Ci.nsIHttpProtocolHandler);
+    return {
+      jsVersion: Services.appinfo.version,
+      protocolVersion: "1.3",
+      product:
+        (isHeadless ? "Headless" : "") +
+        `${Services.appinfo.name}/${Services.appinfo.version}`,
+      revision: Services.appinfo.sourceURL.split("/").pop(),
+      userAgent,
+    };
+  }
+
+  close() {
+    // Notify all windows that an application quit has been requested.
+    const cancelQuit = Cc["@mozilla.org/supports-PRBool;1"].createInstance(
+      Ci.nsISupportsPRBool
+    );
+    Services.obs.notifyObservers(cancelQuit, "quit-application-requested");
+
+    // If the shutdown of the application is prevented force quit it instead.
+    const mode = cancelQuit.data
+      ? Ci.nsIAppStartup.eForceQuit
+      : Ci.nsIAppStartup.eAttemptQuit;
+
+    Services.startup.quit(mode);
+  }
+}
diff --git a/remote/cdp/domains/parent/Emulation.sys.mjs b/remote/cdp/domains/parent/Emulation.sys.mjs
new file mode 100644
index 0000000000..f5ce827f0e
--- /dev/null
+++ b/remote/cdp/domains/parent/Emulation.sys.mjs
@@ -0,0 +1,177 @@
+/* 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";
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  NetUtil: "resource://gre/modules/NetUtil.jsm",
+});
+
+const MAX_WINDOW_SIZE = 10000000;
+
+export class Emulation extends Domain {
+  destructor() {
+    this.setUserAgentOverride({ userAgent: "", platform: "" });
+
+    super.destructor();
+  }
+
+  /**
+   * Overrides the values of device screen dimensions.
+   *
+   * Values as modified are:
+   *   - window.screen.width
+   *   - window.screen.height
+   *   - window.innerWidth
+   *   - window.innerHeight
+   *   - "device-width"/"device-height"-related CSS media query results
+   *
+   * @param {Object} options
+   * @param {number} options.width
+   *     Overriding width value in pixels. 0 disables the override.
+   * @param {number} options.height
+   *     Overriding height value in pixels. 0 disables the override.
+   * @param {number} options.deviceScaleFactor
+   *     Overriding device scale factor value. 0 disables the override.
+   * @param {number} options.mobile [not supported]
+   *     Whether to emulate a mobile device. This includes viewport meta tag,
+   *     overlay scrollbars, text autosizing and more.
+   * @param {number} options.screenOrientation
+   *     Screen orientation override [not supported]
+   */
+  async setDeviceMetricsOverride(options = {}) {
+    const { width, height, deviceScaleFactor } = options;
+
+    if (
+      width < 0 ||
+      width > MAX_WINDOW_SIZE ||
+      height < 0 ||
+      height > MAX_WINDOW_SIZE
+    ) {
+      throw new TypeError(
+        `Width and height values must be positive, not greater than ${MAX_WINDOW_SIZE}`
+      );
+    }
+
+    if (typeof deviceScaleFactor != "number") {
+      throw new TypeError("deviceScaleFactor: number expected");
+    }
+
+    if (deviceScaleFactor < 0) {
+      throw new TypeError("deviceScaleFactor: must be positive");
+    }
+
+    const { tab } = this.session.target;
+    const { linkedBrowser: browser } = tab;
+
+    const { browsingContext } = this.session.target;
+    browsingContext.overrideDPPX = deviceScaleFactor;
+
+    // With a value of 0 the current size is used
+    const { layoutViewport } = await this.session.execute(
+      this.session.id,
+      "Page",
+      "getLayoutMetrics"
+    );
+
+    const targetWidth = width > 0 ? width : layoutViewport.clientWidth;
+    const targetHeight = height > 0 ? height : layoutViewport.clientHeight;
+
+    browser.style.setProperty("min-width", targetWidth + "px");
+    browser.style.setProperty("max-width", targetWidth + "px");
+    browser.style.setProperty("min-height", targetHeight + "px");
+    browser.style.setProperty("max-height", targetHeight + "px");
+
+    // Wait until the viewport has been resized
+    await this.executeInChild("_awaitViewportDimensions", {
+      width: targetWidth,
+      height: targetHeight,
+    });
+  }
+
+  /**
+   * Enables touch on platforms which do not support them.
+   *
+   * @param {Object} options
+   * @param {boolean} options.enabled
+   *     Whether the touch event emulation should be enabled.
+   * @param {number=} options.maxTouchPoints [not yet supported]
+   *     Maximum touch points supported. Defaults to one.
+   */
+  async setTouchEmulationEnabled(options = {}) {
+    const { enabled } = options;
+
+    if (typeof enabled != "boolean") {
+      throw new TypeError(
+        "Invalid parameters (enabled: boolean value expected)"
+      );
+    }
+
+    const { browsingContext } = this.session.target;
+    if (enabled) {
+      browsingContext.touchEventsOverride = "enabled";
+    } else {
+      browsingContext.touchEventsOverride = "none";
+    }
+  }
+
+  /**
+   * Allows overriding user agent with the given string.
+   *
+   * @param {Object} options
+   * @param {string} options.userAgent
+   *     User agent to use.
+   * @param {string=} options.acceptLanguage [not yet supported]
+   *     Browser langugage to emulate.
+   * @param {string=} options.platform
+   *     The platform navigator.platform should return.
+   */
+  async setUserAgentOverride(options = {}) {
+    const { userAgent, platform } = options;
+
+    if (typeof userAgent != "string") {
+      throw new TypeError(
+        "Invalid parameters (userAgent: string value expected)"
+      );
+    }
+
+    if (!["undefined", "string"].includes(typeof platform)) {
+      throw new TypeError("platform: string value expected");
+    }
+
+    const { browsingContext } = this.session.target;
+
+    if (!userAgent.length) {
+      browsingContext.customUserAgent = null;
+    } else if (this._isValidHTTPRequestHeaderValue(userAgent)) {
+      browsingContext.customUserAgent = userAgent;
+    } else {
+      throw new TypeError("Invalid characters found in userAgent");
+    }
+
+    if (platform?.length > 0) {
+      browsingContext.customPlatform = platform;
+    } else {
+      browsingContext.customPlatform = null;
+    }
+  }
+
+  _isValidHTTPRequestHeaderValue(value) {
+    try {
+      const channel = lazy.NetUtil.newChannel({
+        uri: "http://localhost",
+        loadUsingSystemPrincipal: true,
+      });
+      channel.QueryInterface(Ci.nsIHttpChannel);
+      channel.setRequestHeader("X-check", value, false);
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+}
diff --git a/remote/cdp/domains/parent/Fetch.sys.mjs b/remote/cdp/domains/parent/Fetch.sys.mjs
new file mode 100644
index 0000000000..39e6965ccd
--- /dev/null
+++ b/remote/cdp/domains/parent/Fetch.sys.mjs
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+// Note: For now this domain has only been added so that clients using CDP
+// (like Selenium) don't break when trying to disable Fetch events.
+
+export class Fetch extends Domain {
+  constructor(session) {
+    super(session);
+
+    this.enabled = false;
+  }
+
+  destructor() {
+    this.disable();
+
+    super.destructor();
+  }
+
+  disable() {
+    if (!this.enabled) {
+      return;
+    }
+
+    this.enabled = false;
+  }
+}
diff --git a/remote/cdp/domains/parent/IO.sys.mjs b/remote/cdp/domains/parent/IO.sys.mjs
new file mode 100644
index 0000000000..f0877d017f
--- /dev/null
+++ b/remote/cdp/domains/parent/IO.sys.mjs
@@ -0,0 +1,114 @@
+/* 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";
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+import { StreamRegistry } from "chrome://remote/content/cdp/StreamRegistry.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  OS: "resource://gre/modules/osfile.jsm",
+});
+
+const DEFAULT_CHUNK_SIZE = 10 * 1024 * 1024;
+
+// Global singleton for managing open streams
+export const streamRegistry = new StreamRegistry();
+
+export class IO extends Domain {
+  // commands
+
+  /**
+   * Close the stream, discard any temporary backing storage.
+   *
+   * @param {Object} options
+   * @param {string} options.handle
+   *     Handle of the stream to close.
+   */
+  async close(options = {}) {
+    const { handle } = options;
+
+    if (typeof handle != "string") {
+      throw new TypeError(`handle: string value expected`);
+    }
+
+    await streamRegistry.remove(handle);
+  }
+
+  /**
+   * Read a chunk of the stream.
+   *
+   * @param {Object} options
+   * @param {string} options.handle
+   *     Handle of the stream to read.
+   * @param {number=} options.offset
+   *     Seek to the specified offset before reading. If not specificed,
+   *     proceed with offset following the last read.
+   *     Some types of streams may only support sequential reads.
+   * @param {number=} options.size
+   *     Maximum number of bytes to read (left upon the agent
+   *     discretion if not specified).
+   *
+   * @return {string, boolean, boolean}
+   *     Data that were read, including flags for base64-encoded, and end-of-file reached.
+   */
+  async read(options = {}) {
+    const { handle, offset, size } = options;
+
+    if (typeof handle != "string") {
+      throw new TypeError(`handle: string value expected`);
+    }
+
+    const stream = streamRegistry.get(handle);
+    const fileInfo = await stream.stat();
+
+    if (typeof offset != "undefined") {
+      if (typeof offset != "number") {
+        throw new TypeError(`offset: integer value expected`);
+      }
+
+      // To keep compatibility with Chrome clip invalid offsets
+      const seekTo = Math.max(0, Math.min(offset, fileInfo.size));
+      await stream.setPosition(seekTo, lazy.OS.File.POS_START);
+    }
+
+    const curPos = await stream.getPosition();
+    const remainingBytes = fileInfo.size - curPos;
+
+    let chunkSize;
+    if (typeof size != "undefined") {
+      if (typeof size != "number") {
+        throw new TypeError(`size: integer value expected`);
+      }
+
+      // Chromium currently crashes for negative sizes (https://bit.ly/2P6h0Fv),
+      // but might behave similar to the offset and clip invalid values
+      chunkSize = Math.max(0, Math.min(size, remainingBytes));
+    } else {
+      chunkSize = Math.min(DEFAULT_CHUNK_SIZE, remainingBytes);
+    }
+
+    const bytes = await stream.read(chunkSize);
+    // Each UCS2 character has an upper byte of 0 and a lower byte matching
+    // the binary data. Using a loop here prevents us from hitting the browser's
+    // internal `arguments.length` limit.
+    const ARGS_MAX = 262144;
+    const stringData = [];
+    for (let i = 0; i < bytes.length; i += ARGS_MAX) {
+      let argsChunk = Math.min(bytes.length, i + ARGS_MAX);
+      stringData.push(
+        String.fromCharCode.apply(null, bytes.slice(i, argsChunk))
+      );
+    }
+    const data = btoa(stringData.join(""));
+
+    return {
+      data,
+      base64Encoded: true,
+      eof: remainingBytes - bytes.length == 0,
+    };
+  }
+}
diff --git a/remote/cdp/domains/parent/Input.sys.mjs b/remote/cdp/domains/parent/Input.sys.mjs
new file mode 100644
index 0000000000..b3b7fd253b
--- /dev/null
+++ b/remote/cdp/domains/parent/Input.sys.mjs
@@ -0,0 +1,168 @@
+/* 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 { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+export class Input extends Domain {
+  // commands
+
+  /**
+   * Simulate key events.
+   *
+   * @param {Object} options
+   *        - autoRepeat (not supported)
+   *        - code (not supported)
+   *        - key
+   *        - isKeypad (not supported)
+   *        - location (not supported)
+   *        - modifiers
+   *        - text (not supported)
+   *        - type
+   *        - unmodifiedText (not supported)
+   *        - windowsVirtualKeyCode
+   *        - nativeVirtualKeyCode (not supported)
+   *        - keyIdentifier (not supported)
+   *        - isSystemKey (not supported)
+   */
+  async dispatchKeyEvent(options = {}) {
+    // missing code, text, unmodifiedText, autorepeat, location, iskeypad
+    const { key, modifiers, type, windowsVirtualKeyCode } = options;
+    const { alt, ctrl, meta, shift } = Input.Modifier;
+
+    let domType;
+    if (type == "keyDown" || type == "rawKeyDown") {
+      // 'rawKeyDown' is passed as type by puppeteer for all non-text keydown events:
+      // See https://github.com/GoogleChrome/puppeteer/blob/2d99d85976dcb28cc6e3bad4b6a00cd61a67a2cf/lib/Input.js#L52
+      // For now we simply map rawKeyDown to keydown.
+      domType = "keydown";
+    } else if (type == "keyUp" || type == "char") {
+      // 'char' is fired as a single key event. Behind the scenes it will trigger keydown,
+      // keypress and keyup. `domType` will only be used as the event to wait for.
+      domType = "keyup";
+    } else {
+      throw new Error(`Unknown key event type ${type}`);
+    }
+
+    const { browser } = this.session.target;
+    const browserWindow = browser.ownerGlobal;
+
+    const EventUtils = this._getEventUtils(browserWindow);
+    const eventId = await this.executeInChild(
+      "_addContentEventListener",
+      domType
+    );
+
+    if (type == "char") {
+      // type == "char" is used when doing `await page.keyboard.type( 'I’m a list' );`
+      // the ’ character will be calling dispatchKeyEvent only once with type=char.
+      EventUtils.synthesizeKey(key, {}, browserWindow);
+    } else {
+      // Non printable keys should be prefixed with `KEY_`
+      const eventUtilsKey = key.length == 1 ? key : "KEY_" + key;
+      const eventInfo = {
+        keyCode: windowsVirtualKeyCode,
+        type: domType,
+        altKey: !!(modifiers & alt),
+        ctrlKey: !!(modifiers & ctrl),
+        metaKey: !!(modifiers & meta),
+        shiftKey: !!(modifiers & shift),
+      };
+      EventUtils.synthesizeKey(eventUtilsKey, eventInfo, browserWindow);
+    }
+
+    await this.executeInChild("_waitForContentEvent", eventId);
+  }
+
+  /**
+   * Simulate mouse events.
+   *
+   * @param {Object} options
+   * @param {string} options.type
+   * @param {number} options.x
+   * @param {number} options.y
+   * @param {number} options.modifiers
+   * @param {number} options.timestamp [Not Supported]
+   * @param {string} options.button
+   * @param {number} options.buttons [Not Supported]
+   * @param {string} options.clickCount
+   * @param {number} options.deltaX [Not Supported]
+   * @param {number} options.deltaY [Not Supported]
+   * @param {string} options.pointerType [Not Supported]
+   */
+  async dispatchMouseEvent(options = {}) {
+    const { button, clickCount, modifiers, type, x, y } = options;
+    const { alt, ctrl, meta, shift } = Input.Modifier;
+
+    let domType;
+    if (type === "mousePressed") {
+      domType = "mousedown";
+    } else if (type === "mouseReleased") {
+      domType = "mouseup";
+    } else if (type === "mouseMoved") {
+      domType = "mousemove";
+    } else {
+      throw new Error(`Mouse type is not supported: ${type}`);
+    }
+
+    if (domType === "mousedown" && button === "right") {
+      domType = "contextmenu";
+    }
+
+    const buttonID = Input.Button[button] || Input.Button.left;
+    const { browser } = this.session.target;
+    const currentWindow = browser.ownerGlobal;
+
+    const EventUtils = this._getEventUtils(currentWindow);
+    const eventId = await this.executeInChild(
+      "_addContentEventListener",
+      domType
+    );
+
+    EventUtils.synthesizeMouse(browser, x, y, {
+      type: domType,
+      button: buttonID,
+      clickCount: clickCount || 1,
+      altKey: !!(modifiers & alt),
+      ctrlKey: !!(modifiers & ctrl),
+      metaKey: !!(modifiers & meta),
+      shiftKey: !!(modifiers & shift),
+    });
+
+    await this.executeInChild("_waitForContentEvent", eventId);
+  }
+
+  /**
+   * Memoized EventUtils getter.
+   */
+  _getEventUtils(win) {
+    if (!this._eventUtils) {
+      this._eventUtils = {
+        window: win,
+        parent: win,
+        _EU_Ci: Ci,
+        _EU_Cc: Cc,
+      };
+      Services.scriptloader.loadSubScript(
+        "chrome://remote/content/external/EventUtils.js",
+        this._eventUtils
+      );
+    }
+    return this._eventUtils;
+  }
+}
+
+Input.Button = {
+  left: 0,
+  middle: 1,
+  right: 2,
+  back: 3,
+  forward: 4,
+};
+
+Input.Modifier = {
+  alt: 1,
+  ctrl: 2,
+  meta: 4,
+  shift: 8,
+};
diff --git a/remote/cdp/domains/parent/Network.sys.mjs b/remote/cdp/domains/parent/Network.sys.mjs
new file mode 100644
index 0000000000..bccebe7aed
--- /dev/null
+++ b/remote/cdp/domains/parent/Network.sys.mjs
@@ -0,0 +1,538 @@
+/* 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 { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+const MAX_COOKIE_EXPIRY = Number.MAX_SAFE_INTEGER;
+
+const LOAD_CAUSE_STRINGS = {
+  [Ci.nsIContentPolicy.TYPE_INVALID]: "Invalid",
+  [Ci.nsIContentPolicy.TYPE_OTHER]: "Other",
+  [Ci.nsIContentPolicy.TYPE_SCRIPT]: "Script",
+  [Ci.nsIContentPolicy.TYPE_IMAGE]: "Img",
+  [Ci.nsIContentPolicy.TYPE_STYLESHEET]: "Stylesheet",
+  [Ci.nsIContentPolicy.TYPE_OBJECT]: "Object",
+  [Ci.nsIContentPolicy.TYPE_DOCUMENT]: "Document",
+  [Ci.nsIContentPolicy.TYPE_SUBDOCUMENT]: "Subdocument",
+  [Ci.nsIContentPolicy.TYPE_PING]: "Ping",
+  [Ci.nsIContentPolicy.TYPE_XMLHTTPREQUEST]: "Xhr",
+  [Ci.nsIContentPolicy.TYPE_OBJECT_SUBREQUEST]: "ObjectSubdoc",
+  [Ci.nsIContentPolicy.TYPE_DTD]: "Dtd",
+  [Ci.nsIContentPolicy.TYPE_FONT]: "Font",
+  [Ci.nsIContentPolicy.TYPE_MEDIA]: "Media",
+  [Ci.nsIContentPolicy.TYPE_WEBSOCKET]: "Websocket",
+  [Ci.nsIContentPolicy.TYPE_CSP_REPORT]: "Csp",
+  [Ci.nsIContentPolicy.TYPE_XSLT]: "Xslt",
+  [Ci.nsIContentPolicy.TYPE_BEACON]: "Beacon",
+  [Ci.nsIContentPolicy.TYPE_FETCH]: "Fetch",
+  [Ci.nsIContentPolicy.TYPE_IMAGESET]: "Imageset",
+  [Ci.nsIContentPolicy.TYPE_WEB_MANIFEST]: "WebManifest",
+  [Ci.nsIContentPolicy.TYPE_WEB_IDENTITY]: "Webidentity",
+};
+
+export class Network extends Domain {
+  constructor(session) {
+    super(session);
+    this.enabled = false;
+
+    this._onRequest = this._onRequest.bind(this);
+    this._onResponse = this._onResponse.bind(this);
+  }
+
+  destructor() {
+    this.disable();
+
+    super.destructor();
+  }
+
+  enable() {
+    if (this.enabled) {
+      return;
+    }
+    this.enabled = true;
+    this.session.networkObserver.startTrackingBrowserNetwork(
+      this.session.target.browser
+    );
+    this.session.networkObserver.on("request", this._onRequest);
+    this.session.networkObserver.on("response", this._onResponse);
+  }
+
+  disable() {
+    if (!this.enabled) {
+      return;
+    }
+    this.session.networkObserver.stopTrackingBrowserNetwork(
+      this.session.target.browser
+    );
+    this.session.networkObserver.off("request", this._onRequest);
+    this.session.networkObserver.off("response", this._onResponse);
+    this.enabled = false;
+  }
+
+  /**
+   * Deletes browser cookies with matching name and url or domain/path pair.
+   *
+   * @param {Object} options
+   * @param {string} name
+   *     Name of the cookies to remove.
+   * @param {string=} url
+   *     If specified, deletes all the cookies with the given name
+   *     where domain and path match provided URL.
+   * @param {string=} domain
+   *     If specified, deletes only cookies with the exact domain.
+   * @param {string=} path
+   *     If specified, deletes only cookies with the exact path.
+   */
+  async deleteCookies(options = {}) {
+    const { domain, name, path = "/", url } = options;
+
+    if (typeof name != "string") {
+      throw new TypeError("name: string value expected");
+    }
+
+    if (!url && !domain) {
+      throw new TypeError(
+        "At least one of the url and domain needs to be specified"
+      );
+    }
+
+    // Retrieve host. Check domain first because it has precedence.
+    let hostname = domain || "";
+    if (!hostname.length) {
+      const cookieURL = new URL(url);
+      if (!["http:", "https:"].includes(cookieURL.protocol)) {
+        throw new TypeError("An http or https url must be specified");
+      }
+      hostname = cookieURL.hostname;
+    }
+
+    const cookiesFound = Services.cookies.getCookiesWithOriginAttributes(
+      JSON.stringify({}),
+      hostname
+    );
+
+    for (const cookie of cookiesFound) {
+      if (cookie.name == name && cookie.path.startsWith(path)) {
+        Services.cookies.remove(
+          cookie.host,
+          cookie.name,
+          cookie.path,
+          cookie.originAttributes
+        );
+      }
+    }
+  }
+
+  /**
+   * Activates emulation of network conditions.
+   *
+   * @param {Object} options
+   * @param {boolean} offline
+   *     True to emulate internet disconnection.
+   */
+  emulateNetworkConditions(options = {}) {
+    const { offline } = options;
+
+    if (typeof offline != "boolean") {
+      throw new TypeError("offline: boolean value expected");
+    }
+
+    Services.io.offline = offline;
+  }
+
+  /**
+   * Returns all browser cookies.
+   *
+   * Depending on the backend support, will return detailed cookie information in the cookies field.
+   *
+   * @param {Object} options
+   *
+   * @return {Array<Cookie>}
+   *     Array of cookie objects.
+   */
+  async getAllCookies(options = {}) {
+    const cookies = [];
+    for (const cookie of Services.cookies.cookies) {
+      cookies.push(_buildCookie(cookie));
+    }
+
+    return { cookies };
+  }
+
+  /**
+   * Returns all browser cookies for the current URL.
+   *
+   * @param {Object} options
+   * @param {Array<string>=} urls
+   *     The list of URLs for which applicable cookies will be fetched.
+   *     Defaults to the currently open URL.
+   *
+   * @return {Array<Cookie>}
+   *     Array of cookie objects.
+   */
+  async getCookies(options = {}) {
+    const { urls = this._getDefaultUrls() } = options;
+
+    if (!Array.isArray(urls)) {
+      throw new TypeError("urls: array expected");
+    }
+
+    for (const [index, url] of urls.entries()) {
+      if (typeof url !== "string") {
+        throw new TypeError(`urls: string value expected at index ${index}`);
+      }
+    }
+
+    const cookies = [];
+    for (let url of urls) {
+      url = new URL(url);
+
+      const secureProtocol = ["https:", "wss:"].includes(url.protocol);
+
+      const cookiesFound = Services.cookies.getCookiesWithOriginAttributes(
+        JSON.stringify({}),
+        url.hostname
+      );
+
+      for (const cookie of cookiesFound) {
+        // Ignore secure cookies for non-secure protocols
+        if (cookie.isSecure && !secureProtocol) {
+          continue;
+        }
+
+        // Ignore cookies which do not match the given path
+        if (!url.pathname.startsWith(cookie.path)) {
+          continue;
+        }
+
+        const builtCookie = _buildCookie(cookie);
+        const duplicateCookie = cookies.some(value => {
+          return (
+            value.name === builtCookie.name &&
+            value.path === builtCookie.path &&
+            value.domain === builtCookie.domain
+          );
+        });
+
+        if (duplicateCookie) {
+          continue;
+        }
+
+        cookies.push(builtCookie);
+      }
+    }
+
+    return { cookies };
+  }
+
+  /**
+   * Sets a cookie with the given cookie data.
+   *
+   * Note that it may overwrite equivalent cookies if they exist.
+   *
+   * @param {Object} cookie
+   * @param {string} name
+   *     Cookie name.
+   * @param {string} value
+   *     Cookie value.
+   * @param {string=} domain
+   *     Cookie domain.
+   * @param {number=} expires
+   *     Cookie expiration date, session cookie if not set.
+   * @param {boolean=} httpOnly
+   *     True if cookie is http-only.
+   * @param {string=} path
+   *     Cookie path.
+   * @param {string=} sameSite
+   *     Cookie SameSite type.
+   * @param {boolean=} secure
+   *     True if cookie is secure.
+   * @param {string=} url
+   *     The request-URI to associate with the setting of the cookie.
+   *     This value can affect the default domain and path values of the
+   *     created cookie.
+   *
+   * @return {boolean}
+   *     True if successfully set cookie.
+   */
+  setCookie(cookie) {
+    if (typeof cookie.name != "string") {
+      throw new TypeError("name: string value expected");
+    }
+
+    if (typeof cookie.value != "string") {
+      throw new TypeError("value: string value expected");
+    }
+
+    if (
+      typeof cookie.url == "undefined" &&
+      typeof cookie.domain == "undefined"
+    ) {
+      throw new TypeError(
+        "At least one of the url and domain needs to be specified"
+      );
+    }
+
+    // Retrieve host. Check domain first because it has precedence.
+    let hostname = cookie.domain || "";
+    let cookieURL;
+    let schemeType = Ci.nsICookie.SCHEME_UNSET;
+    if (!hostname.length) {
+      try {
+        cookieURL = new URL(cookie.url);
+      } catch (e) {
+        return { success: false };
+      }
+
+      if (!["http:", "https:"].includes(cookieURL.protocol)) {
+        throw new TypeError(`Invalid protocol ${cookieURL.protocol}`);
+      }
+
+      if (cookieURL.protocol == "https:") {
+        cookie.secure = true;
+        schemeType = Ci.nsICookie.SCHEME_HTTPS;
+      } else {
+        schemeType = Ci.nsICookie.SCHEME_HTTP;
+      }
+
+      hostname = cookieURL.hostname;
+    }
+
+    if (typeof cookie.path == "undefined") {
+      cookie.path = "/";
+    }
+
+    let isSession = false;
+    if (typeof cookie.expires == "undefined") {
+      isSession = true;
+      cookie.expires = MAX_COOKIE_EXPIRY;
+    }
+
+    const sameSiteMap = new Map([
+      ["None", Ci.nsICookie.SAMESITE_NONE],
+      ["Lax", Ci.nsICookie.SAMESITE_LAX],
+      ["Strict", Ci.nsICookie.SAMESITE_STRICT],
+    ]);
+
+    let success = true;
+    try {
+      Services.cookies.add(
+        hostname,
+        cookie.path,
+        cookie.name,
+        cookie.value,
+        cookie.secure,
+        cookie.httpOnly || false,
+        isSession,
+        cookie.expires,
+        {} /* originAttributes */,
+        sameSiteMap.get(cookie.sameSite),
+        schemeType
+      );
+    } catch (e) {
+      success = false;
+    }
+
+    return { success };
+  }
+
+  /**
+   * Sets given cookies.
+   *
+   * @param {Object} options
+   * @param {Array.<Cookie>} cookies
+   *     Cookies to be set.
+   */
+  setCookies(options = {}) {
+    const { cookies } = options;
+
+    if (!Array.isArray(cookies)) {
+      throw new TypeError("Invalid parameters (cookies: array expected)");
+    }
+
+    cookies.forEach(cookie => {
+      const { success } = this.setCookie(cookie);
+      if (!success) {
+        throw new Error("Invalid cookie fields");
+      }
+    });
+  }
+
+  /**
+   * Toggles ignoring cache for each request. If true, cache will not be used.
+   *
+   * @param {Object} options
+   * @param {boolean} options.cacheDisabled
+   *     Cache disabled state.
+   */
+  async setCacheDisabled(options = {}) {
+    const { cacheDisabled = false } = options;
+
+    const { INHIBIT_CACHING, LOAD_BYPASS_CACHE, LOAD_NORMAL } = Ci.nsIRequest;
+
+    let loadFlags = LOAD_NORMAL;
+    if (cacheDisabled) {
+      loadFlags = LOAD_BYPASS_CACHE | INHIBIT_CACHING;
+    }
+
+    await this.executeInChild("_updateLoadFlags", loadFlags);
+  }
+
+  /**
+   * Allows overriding user agent with the given string.
+   *
+   * Redirected to Emulation.setUserAgentOverride.
+   */
+  setUserAgentOverride(options = {}) {
+    const { id } = this.session;
+    this.session.execute(id, "Emulation", "setUserAgentOverride", options);
+  }
+
+  _onRequest(eventName, httpChannel, data) {
+    const wrappedChannel = ChannelWrapper.get(httpChannel);
+    const urlFragment = httpChannel.URI.hasRef
+      ? "#" + httpChannel.URI.ref
+      : undefined;
+
+    const request = {
+      url: httpChannel.URI.specIgnoringRef,
+      urlFragment,
+      method: httpChannel.requestMethod,
+      headers: headersAsObject(data.headers),
+      postData: undefined,
+      hasPostData: false,
+      mixedContentType: undefined,
+      initialPriority: undefined,
+      referrerPolicy: undefined,
+      isLinkPreload: false,
+    };
+    this.emit("Network.requestWillBeSent", {
+      requestId: data.requestId,
+      loaderId: data.loaderId,
+      documentURL:
+        wrappedChannel.documentURL || httpChannel.URI.specIgnoringRef,
+      request,
+      timestamp: Date.now() / 1000,
+      wallTime: undefined,
+      initiator: undefined,
+      redirectResponse: undefined,
+      type: LOAD_CAUSE_STRINGS[data.cause] || "unknown",
+      frameId: data.frameId.toString(),
+      hasUserGesture: undefined,
+    });
+  }
+
+  _onResponse(eventName, httpChannel, data) {
+    const wrappedChannel = ChannelWrapper.get(httpChannel);
+    const headers = headersAsObject(data.headers);
+
+    this.emit("Network.responseReceived", {
+      requestId: data.requestId,
+      loaderId: data.loaderId,
+      timestamp: Date.now() / 1000,
+      type: LOAD_CAUSE_STRINGS[data.cause] || "unknown",
+      response: {
+        url: httpChannel.URI.spec,
+        status: data.status,
+        statusText: data.statusText,
+        headers,
+        mimeType: wrappedChannel.contentType,
+        requestHeaders: headersAsObject(data.requestHeaders),
+        connectionReused: undefined,
+        connectionId: undefined,
+        remoteIPAddress: data.remoteIPAddress,
+        remotePort: data.remotePort,
+        fromDiskCache: data.fromCache,
+        encodedDataLength: undefined,
+        protocol: httpChannel.protocolVersion,
+        securityDetails: data.securityDetails,
+        // unknown, neutral, insecure, secure, info, insecure-broken
+        securityState: "unknown",
+      },
+      frameId: data.frameId.toString(),
+    });
+  }
+
+  /**
+   * Creates an array of all Urls in the page context
+   *
+   * @param {Array<string>=} urls
+   */
+  _getDefaultUrls() {
+    const urls = this.session.target.browsingContext
+      .getAllBrowsingContextsInSubtree()
+      .map(context => context.currentURI.spec);
+
+    return urls;
+  }
+}
+
+/**
+ * Creates a CDP Network.Cookie from our internal cookie values
+ *
+ * @param {nsICookie} cookie
+ *
+ * @returns {Network.Cookie}
+ *      A CDP Cookie
+ */
+function _buildCookie(cookie) {
+  const data = {
+    name: cookie.name,
+    value: cookie.value,
+    domain: cookie.host,
+    path: cookie.path,
+    expires: cookie.isSession ? -1 : cookie.expiry,
+    // The size is the combined length of both the cookie name and value
+    size: cookie.name.length + cookie.value.length,
+    httpOnly: cookie.isHttpOnly,
+    secure: cookie.isSecure,
+    session: cookie.isSession,
+  };
+
+  if (cookie.sameSite) {
+    const sameSiteMap = new Map([
+      [Ci.nsICookie.SAMESITE_LAX, "Lax"],
+      [Ci.nsICookie.SAMESITE_STRICT, "Strict"],
+    ]);
+
+    data.sameSite = sameSiteMap.get(cookie.sameSite);
+  }
+
+  return data;
+}
+
+/**
+ * Given a array of possibly repeating header names, merge the values for
+ * duplicate headers into a comma-separated list, or in some cases a
+ * newline-separated list.
+ *
+ * e.g. { "Cache-Control": "no-cache,no-store" }
+ *
+ * Based on
+ * https://hg.mozilla.org/mozilla-central/file/56c09d42f411246e407fe30418c27e67a6a44d29/netwerk/protocol/http/nsHttpHeaderArray.h
+ *
+ * @param {Array} headers
+ *    Array of {name, value}
+ * @returns {Object}
+ *    Object where each key is a header name.
+ */
+function headersAsObject(headers) {
+  const rv = {};
+  headers.forEach(({ name, value }) => {
+    name = name.toLowerCase();
+    if (rv[name]) {
+      const separator = [
+        "set-cookie",
+        "www-authenticate",
+        "proxy-authenticate",
+      ].includes(name)
+        ? "\n"
+        : ",";
+      rv[name] += `${separator}${value}`;
+    } else {
+      rv[name] = value;
+    }
+  });
+  return rv;
+}
diff --git a/remote/cdp/domains/parent/Page.sys.mjs b/remote/cdp/domains/parent/Page.sys.mjs
new file mode 100644
index 0000000000..fd2a747721
--- /dev/null
+++ b/remote/cdp/domains/parent/Page.sys.mjs
@@ -0,0 +1,775 @@
+/* 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";
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  clearInterval: "resource://gre/modules/Timer.sys.mjs",
+  SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
+  setInterval: "resource://gre/modules/Timer.sys.mjs",
+
+  DialogHandler:
+    "chrome://remote/content/cdp/domains/parent/page/DialogHandler.sys.mjs",
+  PollPromise: "chrome://remote/content/shared/Sync.sys.mjs",
+  streamRegistry: "chrome://remote/content/cdp/domains/parent/IO.sys.mjs",
+  TabManager: "chrome://remote/content/shared/TabManager.sys.mjs",
+  UnsupportedError: "chrome://remote/content/cdp/Error.sys.mjs",
+  windowManager: "chrome://remote/content/shared/WindowManager.sys.mjs",
+});
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  OS: "resource://gre/modules/osfile.jsm",
+});
+
+const MAX_CANVAS_DIMENSION = 32767;
+const MAX_CANVAS_AREA = 472907776;
+
+const PRINT_MAX_SCALE_VALUE = 2.0;
+const PRINT_MIN_SCALE_VALUE = 0.1;
+
+const PDF_TRANSFER_MODES = {
+  base64: "ReturnAsBase64",
+  stream: "ReturnAsStream",
+};
+
+const TIMEOUT_SET_HISTORY_INDEX = 1000;
+
+export class Page extends Domain {
+  constructor(session) {
+    super(session);
+
+    this._onDialogLoaded = this._onDialogLoaded.bind(this);
+    this._onRequest = this._onRequest.bind(this);
+
+    this.enabled = false;
+
+    this.session.networkObserver.startTrackingBrowserNetwork(
+      this.session.target.browser
+    );
+    this.session.networkObserver.on("request", this._onRequest);
+  }
+
+  destructor() {
+    // Flip a flag to avoid to disable the content domain from this.disable()
+    this._isDestroyed = false;
+    this.disable();
+
+    this.session.networkObserver.off("request", this._onRequest);
+    this.session.networkObserver.stopTrackingBrowserNetwork(
+      this.session.target.browser
+    );
+    super.destructor();
+  }
+
+  // commands
+
+  /**
+   * Navigates current page to given URL.
+   *
+   * @param {Object} options
+   * @param {string} options.url
+   *     destination URL
+   * @param {string=} options.frameId
+   *     frame id to navigate (not supported),
+   *     if not specified navigate top frame
+   * @param {string=} options.referrer
+   *     referred URL (optional)
+   * @param {string=} options.transitionType
+   *     intended transition type
+   * @return {Object}
+   *         - frameId {string} frame id that has navigated (or failed to)
+   *         - errorText {string=} error message if navigation has failed
+   *         - loaderId {string} (not supported)
+   */
+  async navigate(options = {}) {
+    const { url, frameId, referrer, transitionType } = options;
+    if (typeof url != "string") {
+      throw new TypeError("url: string value expected");
+    }
+    let validURL;
+    try {
+      validURL = Services.io.newURI(url);
+    } catch (e) {
+      throw new Error("Error: Cannot navigate to invalid URL");
+    }
+    const topFrameId = this.session.browsingContext.id.toString();
+    if (frameId && frameId != topFrameId) {
+      throw new lazy.UnsupportedError("frameId not supported");
+    }
+
+    const hitsNetwork = ["https", "http"].includes(validURL.scheme);
+    let networkLessLoaderId;
+    if (!hitsNetwork) {
+      // This navigation will not hit the network, use a randomly generated id.
+      const uuid = Services.uuid.generateUUID().toString();
+      networkLessLoaderId = uuid.substring(1, uuid.length - 1);
+
+      // Update the content process map of loader ids.
+      await this.executeInChild("_updateLoaderId", {
+        frameId: this.session.browsingContext.id,
+        loaderId: networkLessLoaderId,
+      });
+    }
+
+    const currentURI = this.session.browsingContext.currentURI;
+
+    const isSameDocumentNavigation =
+      // The "host", "query" and "ref" getters can throw if the URLs are not
+      // http/https, so verify first that both currentURI and validURL are
+      // using http/https.
+      hitsNetwork &&
+      ["https", "http"].includes(currentURI.scheme) &&
+      currentURI.host === validURL.host &&
+      currentURI.query === validURL.query &&
+      !!validURL.ref;
+
+    const requestDone = new Promise(resolve => {
+      if (isSameDocumentNavigation) {
+        // Per CDP documentation, same-document navigations should not emit any
+        // loader id (https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-navigate)
+        resolve({});
+        return;
+      }
+
+      if (!hitsNetwork) {
+        // This navigation will not hit the network, use a randomly generated id.
+        resolve({ navigationRequestId: networkLessLoaderId });
+        return;
+      }
+      let navigationRequestId, redirectedRequestId;
+      const _onNavigationRequest = function(_type, _ch, data) {
+        const {
+          url: requestURL,
+          requestId,
+          redirectedFrom = null,
+          isNavigationRequest,
+        } = data;
+        if (!isNavigationRequest) {
+          return;
+        }
+        if (validURL.spec === requestURL) {
+          navigationRequestId = redirectedRequestId = requestId;
+        } else if (redirectedFrom === redirectedRequestId) {
+          redirectedRequestId = requestId;
+        }
+      };
+
+      const _onRequestFinished = function(_type, _ch, data) {
+        const { requestId, errorCode } = data;
+        if (
+          redirectedRequestId !== requestId ||
+          errorCode == "NS_BINDING_REDIRECTED"
+        ) {
+          // handle next request in redirection chain
+          return;
+        }
+        this.session.networkObserver.off("request", _onNavigationRequest);
+        this.session.networkObserver.off("requestfinished", _onRequestFinished);
+        resolve({ errorCode, navigationRequestId });
+      }.bind(this);
+
+      this.session.networkObserver.on("request", _onNavigationRequest);
+      this.session.networkObserver.on("requestfinished", _onRequestFinished);
+    });
+
+    const opts = {
+      loadFlags: transitionToLoadFlag(transitionType),
+      referrerURI: referrer,
+      triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
+    };
+    this.session.browsingContext.loadURI(url, opts);
+    // clients expect loaderId == requestId for a document navigation request
+    const { navigationRequestId: loaderId, errorCode } = await requestDone;
+    const result = {
+      frameId: topFrameId,
+      loaderId,
+    };
+    if (errorCode) {
+      result.errorText = errorCode;
+    }
+    return result;
+  }
+
+  /**
+   * Capture page screenshot.
+   *
+   * @param {Object} options
+   * @param {Viewport=} options.clip
+   *     Capture the screenshot of a given region only.
+   * @param {string=} options.format
+   *     Image compression format. Defaults to "png".
+   * @param {number=} options.quality
+   *     Compression quality from range [0..100] (jpeg only). Defaults to 80.
+   *
+   * @return {string}
+   *     Base64-encoded image data.
+   */
+  async captureScreenshot(options = {}) {
+    const { clip, format = "png", quality = 80 } = options;
+
+    if (options.fromSurface) {
+      throw new lazy.UnsupportedError("fromSurface not supported");
+    }
+
+    let rect;
+    let scale = await this.executeInChild("_devicePixelRatio");
+
+    if (clip) {
+      for (const prop of ["x", "y", "width", "height", "scale"]) {
+        if (clip[prop] == undefined) {
+          throw new TypeError(`clip.${prop}: double value expected`);
+        }
+      }
+
+      const contentRect = await this.executeInChild("_contentRect");
+
+      // For invalid scale values default to full page
+      if (clip.scale <= 0) {
+        Object.assign(clip, {
+          x: 0,
+          y: 0,
+          width: contentRect.width,
+          height: contentRect.height,
+          scale: 1,
+        });
+      } else {
+        if (clip.x < 0 || clip.x > contentRect.width - 1) {
+          clip.x = 0;
+        }
+        if (clip.y < 0 || clip.y > contentRect.height - 1) {
+          clip.y = 0;
+        }
+        if (clip.width <= 0) {
+          clip.width = contentRect.width;
+        }
+        if (clip.height <= 0) {
+          clip.height = contentRect.height;
+        }
+      }
+
+      rect = new DOMRect(clip.x, clip.y, clip.width, clip.height);
+      scale *= clip.scale;
+    } else {
+      // If no specific clipping region has been specified,
+      // fallback to the layout (fixed) viewport, and the
+      // default pixel ratio.
+      const {
+        pageX,
+        pageY,
+        clientWidth,
+        clientHeight,
+      } = await this.executeInChild("_layoutViewport");
+
+      rect = new DOMRect(pageX, pageY, clientWidth, clientHeight);
+    }
+
+    let canvasWidth = rect.width * scale;
+    let canvasHeight = rect.height * scale;
+
+    // Cap the screenshot size based on maximum allowed canvas sizes.
+    // Using higher dimensions would trigger exceptions in Gecko.
+    //
+    // See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/canvas#Maximum_canvas_size
+    if (canvasWidth > MAX_CANVAS_DIMENSION) {
+      rect.width = Math.floor(MAX_CANVAS_DIMENSION / scale);
+      canvasWidth = rect.width * scale;
+    }
+    if (canvasHeight > MAX_CANVAS_DIMENSION) {
+      rect.height = Math.floor(MAX_CANVAS_DIMENSION / scale);
+      canvasHeight = rect.height * scale;
+    }
+    // If the area is larger, reduce the height to keep the full width.
+    if (canvasWidth * canvasHeight > MAX_CANVAS_AREA) {
+      rect.height = Math.floor(MAX_CANVAS_AREA / (canvasWidth * scale));
+      canvasHeight = rect.height * scale;
+    }
+
+    const { browsingContext, window } = this.session.target;
+    const snapshot = await browsingContext.currentWindowGlobal.drawSnapshot(
+      rect,
+      scale,
+      "rgb(255,255,255)"
+    );
+
+    const canvas = window.document.createElementNS(
+      "http://www.w3.org/1999/xhtml",
+      "canvas"
+    );
+    canvas.width = canvasWidth;
+    canvas.height = canvasHeight;
+
+    const ctx = canvas.getContext("2d");
+    ctx.drawImage(snapshot, 0, 0);
+
+    // Bug 1574935 - Huge dimensions can trigger an OOM because multiple copies
+    // of the bitmap will exist in memory. Force the removal of the snapshot
+    // because it is no longer needed.
+    snapshot.close();
+
+    const url = canvas.toDataURL(`image/${format}`, quality / 100);
+    if (!url.startsWith(`data:image/${format}`)) {
+      throw new lazy.UnsupportedError(`Unsupported MIME type: image/${format}`);
+    }
+
+    // only return the base64 encoded data without the data URL prefix
+    const data = url.substring(url.indexOf(",") + 1);
+
+    return { data };
+  }
+
+  async enable() {
+    if (this.enabled) {
+      return;
+    }
+
+    this.enabled = true;
+
+    const { browser } = this.session.target;
+    this._dialogHandler = new lazy.DialogHandler(browser);
+    this._dialogHandler.on("dialog-loaded", this._onDialogLoaded);
+    await this.executeInChild("enable");
+  }
+
+  async disable() {
+    if (!this.enabled) {
+      return;
+    }
+
+    this._dialogHandler.destructor();
+    this._dialogHandler = null;
+    this.enabled = false;
+
+    if (!this._isDestroyed) {
+      // Only call disable in the content domain if we are not destroying the domain.
+      // If we are destroying the domain, the content domains will be destroyed
+      // independently after firing the remote:destroy event.
+      await this.executeInChild("disable");
+    }
+  }
+
+  async bringToFront() {
+    const { tab, window } = this.session.target;
+
+    // Focus the window, and select the corresponding tab
+    await lazy.windowManager.focusWindow(window);
+    await lazy.TabManager.selectTab(tab);
+  }
+
+  /**
+   * Return metrics relating to the layouting of the page.
+   *
+   * The returned object contains the following entries:
+   *
+   * layoutViewport:
+   *     {number} pageX
+   *         Horizontal offset relative to the document (CSS pixels)
+   *     {number} pageY
+   *         Vertical offset relative to the document (CSS pixels)
+   *     {number} clientWidth
+   *         Width (CSS pixels), excludes scrollbar if present
+   *     {number} clientHeight
+   *         Height (CSS pixels), excludes scrollbar if present
+   *
+   * visualViewport:
+   *     {number} offsetX
+   *         Horizontal offset relative to the layout viewport (CSS pixels)
+   *     {number} offsetY
+   *         Vertical offset relative to the layout viewport (CSS pixels)
+   *     {number} pageX
+   *         Horizontal offset relative to the document (CSS pixels)
+   *     {number} pageY
+   *         Vertical offset relative to the document (CSS pixels)
+   *     {number} clientWidth
+   *         Width (CSS pixels), excludes scrollbar if present
+   *     {number} clientHeight
+   *         Height (CSS pixels), excludes scrollbar if present
+   *     {number} scale
+   *         Scale relative to the ideal viewport (size at width=device-width)
+   *     {number} zoom
+   *         Page zoom factor (CSS to device independent pixels ratio)
+   *
+   * contentSize:
+   *     {number} x
+   *         X coordinate
+   *     {number} y
+   *         Y coordinate
+   *     {number} width
+   *         Width of scrollable area
+   *     {number} height
+   *         Height of scrollable area
+   *
+   * @return {Promise}
+   * @resolves {layoutViewport, visualViewport, contentSize}
+   */
+  async getLayoutMetrics() {
+    return {
+      layoutViewport: await this.executeInChild("_layoutViewport"),
+      contentSize: await this.executeInChild("_contentRect"),
+    };
+  }
+
+  /**
+   * Returns navigation history for the current page.
+   *
+   * @return {currentIndex:number, entries:Array<NavigationEntry>}
+   */
+  async getNavigationHistory() {
+    const { window } = this.session.target;
+
+    return new Promise(resolve => {
+      function updateSessionHistory(sessionHistory) {
+        const entries = sessionHistory.entries.map(entry => {
+          return {
+            id: entry.ID,
+            url: entry.url,
+            userTypedURL: entry.originalURI || entry.url,
+            title: entry.title,
+            // TODO: Bug 1609514
+            transitionType: null,
+          };
+        });
+
+        resolve({
+          currentIndex: sessionHistory.index,
+          entries,
+        });
+      }
+
+      lazy.SessionStore.getSessionHistory(
+        window.gBrowser.selectedTab,
+        updateSessionHistory
+      );
+    });
+  }
+
+  /**
+   * Interact with the currently opened JavaScript dialog (alert, confirm,
+   * prompt) for this page. This will always close the dialog, either accepting
+   * or rejecting it, with the optional prompt filled.
+   *
+   * @param {Object} options
+   * @param {boolean=} options.accept
+   *    for "confirm", "prompt", "beforeunload" dialogs true will accept
+   *    the dialog, false will cancel it. For "alert" dialogs, true or
+   *    false closes the dialog in the same way.
+   * @param {string=} options.promptText
+   *    for "prompt" dialogs, used to fill the prompt input.
+   */
+  async handleJavaScriptDialog(options = {}) {
+    const { accept, promptText } = options;
+
+    if (!this.enabled) {
+      throw new Error("Page domain is not enabled");
+    }
+    await this._dialogHandler.handleJavaScriptDialog({ accept, promptText });
+  }
+
+  /**
+   * Navigates current page to the given history entry.
+   *
+   * @param {Object} options
+   * @param {number} options.entryId
+   *    Unique id of the entry to navigate to.
+   */
+  async navigateToHistoryEntry(options = {}) {
+    const { entryId } = options;
+
+    const index = await this._getIndexForHistoryEntryId(entryId);
+
+    if (index == null) {
+      throw new Error("No entry with passed id");
+    }
+
+    const { window } = this.session.target;
+    window.gBrowser.gotoIndex(index);
+
+    // On some platforms the requested index isn't set immediately.
+    await lazy.PollPromise(
+      async (resolve, reject) => {
+        const currentIndex = await this._getCurrentHistoryIndex();
+        if (currentIndex == index) {
+          resolve();
+        } else {
+          reject();
+        }
+      },
+      { timeout: TIMEOUT_SET_HISTORY_INDEX }
+    );
+  }
+
+  /**
+   * Print page as PDF.
+   *
+   * @param {Object} options
+   * @param {boolean=} options.displayHeaderFooter
+   *     Display header and footer. Defaults to false.
+   * @param {string=} options.footerTemplate (not supported)
+   *     HTML template for the print footer.
+   * @param {string=} options.headerTemplate (not supported)
+   *     HTML template for the print header. Should use the same format
+   *     as the footerTemplate.
+   * @param {boolean=} options.ignoreInvalidPageRanges
+   *     Whether to silently ignore invalid but successfully parsed page ranges,
+   *     such as '3-2'. Defaults to false.
+   * @param {boolean=} options.landscape
+   *     Paper orientation. Defaults to false.
+   * @param {number=} options.marginBottom
+   *     Bottom margin in inches. Defaults to 1cm (~0.4 inches).
+   * @param {number=} options.marginLeft
+   *     Left margin in inches. Defaults to 1cm (~0.4 inches).
+   * @param {number=} options.marginRight
+   *     Right margin in inches. Defaults to 1cm (~0.4 inches).
+   * @param {number=} options.marginTop
+   *     Top margin in inches. Defaults to 1cm (~0.4 inches).
+   * @param {string=} options.pageRanges (not supported)
+   *     Paper ranges to print, e.g., '1-5, 8, 11-13'.
+   *     Defaults to the empty string, which means print all pages.
+   * @param {number=} options.paperHeight
+   *     Paper height in inches. Defaults to 11 inches.
+   * @param {number=} options.paperWidth
+   *     Paper width in inches. Defaults to 8.5 inches.
+   * @param {boolean=} options.preferCSSPageSize
+   *     Whether or not to prefer page size as defined by CSS.
+   *     Defaults to false, in which case the content will be scaled
+   *     to fit the paper size.
+   * @param {boolean=} options.printBackground
+   *     Print background graphics. Defaults to false.
+   * @param {number=} options.scale
+   *     Scale of the webpage rendering. Defaults to 1.
+   * @param {string=} options.transferMode
+   *     Return as base64-encoded string (ReturnAsBase64),
+   *     or stream (ReturnAsStream). Defaults to ReturnAsBase64.
+   *
+   * @return {Promise<{data:string, stream:string}>
+   *     Based on the transferMode setting data is a base64-encoded string,
+   *     or stream is a handle to a OS.File stream.
+   */
+  async printToPDF(options = {}) {
+    const {
+      displayHeaderFooter = false,
+      // Bug 1601570 - Implement templates for header and footer
+      // headerTemplate = "",
+      // footerTemplate = "",
+      landscape = false,
+      marginBottom = 0.39,
+      marginLeft = 0.39,
+      marginRight = 0.39,
+      marginTop = 0.39,
+      // Bug 1601571 - Implement handling of page ranges
+      // TODO: pageRanges = "",
+      // TODO: ignoreInvalidPageRanges = false,
+      paperHeight = 11.0,
+      paperWidth = 8.5,
+      preferCSSPageSize = false,
+      printBackground = false,
+      scale = 1.0,
+      transferMode = PDF_TRANSFER_MODES.base64,
+    } = options;
+
+    if (marginBottom < 0) {
+      throw new TypeError("marginBottom is negative");
+    }
+    if (marginLeft < 0) {
+      throw new TypeError("marginLeft is negative");
+    }
+    if (marginRight < 0) {
+      throw new TypeError("marginRight is negative");
+    }
+    if (marginTop < 0) {
+      throw new TypeError("marginTop is negative");
+    }
+    if (scale < PRINT_MIN_SCALE_VALUE || scale > PRINT_MAX_SCALE_VALUE) {
+      throw new TypeError("scale is outside [0.1 - 2] range");
+    }
+    if (paperHeight <= 0) {
+      throw new TypeError("paperHeight is zero or negative");
+    }
+    if (paperWidth <= 0) {
+      throw new TypeError("paperWidth is zero or negative");
+    }
+
+    // Create a unique filename for the temporary PDF file
+    const basePath = lazy.OS.Path.join(
+      lazy.OS.Constants.Path.tmpDir,
+      "remote-agent.pdf"
+    );
+    const { file, path: filePath } = await lazy.OS.File.openUnique(basePath);
+    await file.close();
+
+    const psService = Cc["@mozilla.org/gfx/printsettings-service;1"].getService(
+      Ci.nsIPrintSettingsService
+    );
+
+    const printSettings = psService.createNewPrintSettings();
+    printSettings.isInitializedFromPrinter = true;
+    printSettings.isInitializedFromPrefs = true;
+    printSettings.outputFormat = Ci.nsIPrintSettings.kOutputFormatPDF;
+    printSettings.printerName = "";
+    printSettings.printSilent = true;
+    printSettings.outputDestination =
+      Ci.nsIPrintSettings.kOutputDestinationFile;
+    printSettings.toFileName = filePath;
+
+    printSettings.paperSizeUnit = Ci.nsIPrintSettings.kPaperSizeInches;
+    printSettings.paperWidth = paperWidth;
+    printSettings.paperHeight = paperHeight;
+
+    printSettings.marginBottom = marginBottom;
+    printSettings.marginLeft = marginLeft;
+    printSettings.marginRight = marginRight;
+    printSettings.marginTop = marginTop;
+
+    printSettings.printBGColors = printBackground;
+    printSettings.printBGImages = printBackground;
+    printSettings.scaling = scale;
+    printSettings.shrinkToFit = preferCSSPageSize;
+
+    if (!displayHeaderFooter) {
+      printSettings.headerStrCenter = "";
+      printSettings.headerStrLeft = "";
+      printSettings.headerStrRight = "";
+      printSettings.footerStrCenter = "";
+      printSettings.footerStrLeft = "";
+      printSettings.footerStrRight = "";
+    }
+
+    if (landscape) {
+      printSettings.orientation = Ci.nsIPrintSettings.kLandscapeOrientation;
+    }
+
+    const { linkedBrowser } = this.session.target.tab;
+
+    await linkedBrowser.browsingContext.print(printSettings);
+
+    // Bug 1603739 - With e10s enabled the promise returned by print() resolves
+    // too early, which means the file hasn't been completely written.
+    await new Promise(resolve => {
+      const DELAY_CHECK_FILE_COMPLETELY_WRITTEN = 100;
+
+      let lastSize = 0;
+      const timerId = lazy.setInterval(async () => {
+        const fileInfo = await lazy.OS.File.stat(filePath);
+        if (lastSize > 0 && fileInfo.size == lastSize) {
+          lazy.clearInterval(timerId);
+          resolve();
+        }
+        lastSize = fileInfo.size;
+      }, DELAY_CHECK_FILE_COMPLETELY_WRITTEN);
+    });
+
+    const fp = await lazy.OS.File.open(filePath);
+
+    const retval = { data: null, stream: null };
+    if (transferMode == PDF_TRANSFER_MODES.stream) {
+      retval.stream = lazy.streamRegistry.add(fp);
+    } else {
+      // return all data as a base64 encoded string
+      let bytes;
+      try {
+        bytes = await fp.read();
+      } finally {
+        fp.close();
+        await lazy.OS.File.remove(filePath);
+      }
+
+      // Each UCS2 character has an upper byte of 0 and a lower byte matching
+      // the binary data
+      retval.data = btoa(String.fromCharCode.apply(null, bytes));
+    }
+
+    return retval;
+  }
+
+  /**
+   * Intercept file chooser requests and transfer control to protocol clients.
+   *
+   * When file chooser interception is enabled,
+   * the native file chooser dialog is not shown.
+   * Instead, a protocol event Page.fileChooserOpened is emitted.
+   *
+   * @param {Object} options
+   * @param {boolean=} options.enabled
+   *     Enabled state of file chooser interception.
+   */
+  setInterceptFileChooserDialog(options = {}) {}
+
+  _getCurrentHistoryIndex() {
+    const { window } = this.session.target;
+
+    return new Promise(resolve => {
+      lazy.SessionStore.getSessionHistory(
+        window.gBrowser.selectedTab,
+        history => {
+          resolve(history.index);
+        }
+      );
+    });
+  }
+
+  _getIndexForHistoryEntryId(id) {
+    const { window } = this.session.target;
+
+    return new Promise(resolve => {
+      function updateSessionHistory(sessionHistory) {
+        sessionHistory.entries.forEach((entry, index) => {
+          if (entry.ID == id) {
+            resolve(index);
+          }
+        });
+
+        resolve(null);
+      }
+
+      lazy.SessionStore.getSessionHistory(
+        window.gBrowser.selectedTab,
+        updateSessionHistory
+      );
+    });
+  }
+
+  /**
+   * Emit the proper CDP event javascriptDialogOpening when a javascript dialog
+   * opens for the current target.
+   */
+  _onDialogLoaded(e, data) {
+    const { message, type } = data;
+    // XXX: We rely on the tabmodal-dialog-loaded event (see DialogHandler.jsm)
+    // which is inconsistent with the name "javascriptDialogOpening".
+    // For correctness we should rely on an event fired _before_ the prompt is
+    // visible, such as DOMWillOpenModalDialog. However the payload of this
+    // event does not contain enough data to populate javascriptDialogOpening.
+    //
+    // Since the event is fired asynchronously, this should not have an impact
+    // on the actual tests relying on this API.
+    this.emit("Page.javascriptDialogOpening", { message, type });
+  }
+
+  /**
+   * Handles HTTP request to propagate loaderId to events emitted from
+   * content process
+   */
+  _onRequest(_type, _ch, data) {
+    if (!data.loaderId) {
+      return;
+    }
+    this.executeInChild("_updateLoaderId", {
+      loaderId: data.loaderId,
+      frameId: data.frameId,
+    });
+  }
+}
+
+function transitionToLoadFlag(transitionType) {
+  switch (transitionType) {
+    case "reload":
+      return Ci.nsIWebNavigation.LOAD_FLAGS_IS_REFRESH;
+    case "link":
+    default:
+      return Ci.nsIWebNavigation.LOAD_FLAGS_IS_LINK;
+  }
+}
diff --git a/remote/cdp/domains/parent/Security.sys.mjs b/remote/cdp/domains/parent/Security.sys.mjs
new file mode 100644
index 0000000000..73967d73cb
--- /dev/null
+++ b/remote/cdp/domains/parent/Security.sys.mjs
@@ -0,0 +1,58 @@
+/* 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";
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Preferences: "resource://gre/modules/Preferences.sys.mjs",
+});
+
+XPCOMUtils.defineLazyServiceGetters(lazy, {
+  sss: ["@mozilla.org/ssservice;1", "nsISiteSecurityService"],
+  certOverrideService: [
+    "@mozilla.org/security/certoverride;1",
+    "nsICertOverrideService",
+  ],
+});
+
+const CERT_PINNING_ENFORCEMENT_PREF = "security.cert_pinning.enforcement_level";
+const HSTS_PRELOAD_LIST_PREF = "network.stricttransportsecurity.preloadlist";
+
+export class Security extends Domain {
+  destructor() {
+    this.setIgnoreCertificateErrors({ ignore: false });
+  }
+
+  /**
+   * Enable/disable whether all certificate errors should be ignored
+   *
+   * @param {Object} options
+   * @param {boolean=} options.ignore
+   *    if true, all certificate errors will be ignored.
+   */
+  setIgnoreCertificateErrors(options = {}) {
+    const { ignore } = options;
+
+    if (ignore) {
+      // make it possible to register certificate overrides for domains
+      // that use HSTS or HPKP
+      lazy.Preferences.set(HSTS_PRELOAD_LIST_PREF, false);
+      lazy.Preferences.set(CERT_PINNING_ENFORCEMENT_PREF, 0);
+    } else {
+      lazy.Preferences.reset(HSTS_PRELOAD_LIST_PREF);
+      lazy.Preferences.reset(CERT_PINNING_ENFORCEMENT_PREF);
+
+      // clear collected HSTS and HPKP state
+      lazy.sss.clearAll();
+    }
+
+    lazy.certOverrideService.setDisableAllSecurityChecksAndLetAttackersInterceptMyData(
+      ignore
+    );
+  }
+}
diff --git a/remote/cdp/domains/parent/Target.sys.mjs b/remote/cdp/domains/parent/Target.sys.mjs
new file mode 100644
index 0000000000..5f0229ce4d
--- /dev/null
+++ b/remote/cdp/domains/parent/Target.sys.mjs
@@ -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/. */
+
+import { Domain } from "chrome://remote/content/cdp/domains/Domain.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  ContextualIdentityService:
+    "resource://gre/modules/ContextualIdentityService.sys.mjs",
+  MainProcessTarget:
+    "chrome://remote/content/cdp/targets/MainProcessTarget.sys.mjs",
+  TabManager: "chrome://remote/content/shared/TabManager.sys.mjs",
+  TabSession: "chrome://remote/content/cdp/sessions/TabSession.sys.mjs",
+  windowManager: "chrome://remote/content/shared/WindowManager.sys.mjs",
+});
+
+let browserContextIds = 1;
+
+export class Target extends Domain {
+  constructor(session) {
+    super(session);
+
+    this._onTargetCreated = this._onTargetCreated.bind(this);
+    this._onTargetDestroyed = this._onTargetDestroyed.bind(this);
+  }
+
+  getBrowserContexts() {
+    return {
+      browserContextIds: [],
+    };
+  }
+
+  createBrowserContext() {
+    const identity = lazy.ContextualIdentityService.create(
+      "remote-agent-" + browserContextIds++
+    );
+    return { browserContextId: identity.userContextId };
+  }
+
+  disposeBrowserContext(options = {}) {
+    const { browserContextId } = options;
+
+    lazy.ContextualIdentityService.remove(browserContextId);
+    lazy.ContextualIdentityService.closeContainerTabs(browserContextId);
+  }
+
+  getTargets() {
+    const { targetList } = this.session.target;
+
+    const targetInfos = [];
+    for (const target of targetList) {
+      if (target instanceof lazy.MainProcessTarget) {
+        continue;
+      }
+
+      targetInfos.push(this._getTargetInfo(target));
+    }
+
+    return { targetInfos };
+  }
+
+  setDiscoverTargets(options = {}) {
+    const { discover } = options;
+    const { targetList } = this.session.target;
+    if (discover) {
+      targetList.on("target-created", this._onTargetCreated);
+      targetList.on("target-destroyed", this._onTargetDestroyed);
+    } else {
+      targetList.off("target-created", this._onTargetCreated);
+      targetList.off("target-destroyed", this._onTargetDestroyed);
+    }
+    for (const target of targetList) {
+      this._onTargetCreated("target-created", target);
+    }
+  }
+
+  async createTarget(options = {}) {
+    const { browserContextId } = options;
+    const { targetList, window } = this.session.target;
+    const onTarget = targetList.once("target-created");
+    const tab = await lazy.TabManager.addTab({
+      focus: true,
+      userContextId: browserContextId,
+      window,
+    });
+    const target = await onTarget;
+    if (tab.linkedBrowser != target.browser) {
+      throw new Error(
+        "Unexpected tab opened: " + tab.linkedBrowser.currentURI.spec
+      );
+    }
+    return { targetId: target.id };
+  }
+
+  async closeTarget(options = {}) {
+    const { targetId } = options;
+    const { targetList } = this.session.target;
+    const target = targetList.getById(targetId);
+
+    if (!target) {
+      throw new Error(`Unable to find target with id '${targetId}'`);
+    }
+
+    await lazy.TabManager.removeTab(target.tab);
+  }
+
+  async activateTarget(options = {}) {
+    const { targetId } = options;
+    const { targetList, window } = this.session.target;
+    const target = targetList.getById(targetId);
+
+    if (!target) {
+      throw new Error(`Unable to find target with id '${targetId}'`);
+    }
+
+    // Focus the window, and select the corresponding tab
+    await lazy.windowManager.focusWindow(window);
+    await lazy.TabManager.selectTab(target.tab);
+  }
+
+  attachToTarget(options = {}) {
+    const { targetId } = options;
+    const { targetList } = this.session.target;
+    const target = targetList.getById(targetId);
+
+    if (!target) {
+      throw new Error(`Unable to find target with id '${targetId}'`);
+    }
+
+    const tabSession = new lazy.TabSession(
+      this.session.connection,
+      target,
+      Services.uuid
+        .generateUUID()
+        .toString()
+        .slice(1, -1)
+    );
+    this.session.connection.registerSession(tabSession);
+
+    this._emitAttachedToTarget(target, tabSession);
+
+    return {
+      sessionId: tabSession.id,
+    };
+  }
+
+  setAutoAttach() {}
+
+  sendMessageToTarget(options = {}) {
+    const { sessionId, message } = options;
+    const { connection } = this.session;
+    connection.sendMessageToTarget(sessionId, message);
+  }
+
+  /**
+   * Internal methods: the following methods are not part of CDP;
+   * note the _ prefix.
+   */
+
+  _emitAttachedToTarget(target, tabSession) {
+    const targetInfo = this._getTargetInfo(target);
+    this.emit("Target.attachedToTarget", {
+      targetInfo,
+      sessionId: tabSession.id,
+      waitingForDebugger: false,
+    });
+  }
+
+  _getTargetInfo(target) {
+    return {
+      targetId: target.id,
+      type: target.type,
+      title: target.title,
+      url: target.url,
+      // TODO: Correctly determine if target is attached (bug 1680780)
+      attached: target.id == this.session.target.id,
+      browserContextId: target.browserContextId,
+    };
+  }
+
+  _onTargetCreated(eventName, target) {
+    const targetInfo = this._getTargetInfo(target);
+    this.emit("Target.targetCreated", { targetInfo });
+  }
+
+  _onTargetDestroyed(eventName, target) {
+    this.emit("Target.targetDestroyed", {
+      targetId: target.id,
+    });
+  }
+}
diff --git a/remote/cdp/domains/parent/page/DialogHandler.sys.mjs b/remote/cdp/domains/parent/page/DialogHandler.sys.mjs
new file mode 100644
index 0000000000..a142165b4b
--- /dev/null
+++ b/remote/cdp/domains/parent/page/DialogHandler.sys.mjs
@@ -0,0 +1,140 @@
+/* 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, {
+  EventEmitter: "resource://gre/modules/EventEmitter.sys.mjs",
+});
+
+const DIALOG_TYPES = {
+  ALERT: "alert",
+  BEFOREUNLOAD: "beforeunload",
+  CONFIRM: "confirm",
+  PROMPT: "prompt",
+};
+
+/**
+ * Helper dedicated to detect and interact with browser dialogs such as `alert`,
+ * `confirm` etc. The current implementation only supports tabmodal dialogs,
+ * not full window dialogs.
+ *
+ * Emits "dialog-loaded" when a javascript dialog is opened for the current
+ * browser.
+ *
+ * @param {BrowserElement} browser
+ */
+export class DialogHandler {
+  constructor(browser) {
+    lazy.EventEmitter.decorate(this);
+    this._dialog = null;
+    this._browser = browser;
+
+    this._onCommonDialogLoaded = this._onCommonDialogLoaded.bind(this);
+    this._onTabDialogLoaded = this._onTabDialogLoaded.bind(this);
+
+    Services.obs.addObserver(
+      this._onCommonDialogLoaded,
+      "common-dialog-loaded"
+    );
+    Services.obs.addObserver(this._onTabDialogLoaded, "tabmodal-dialog-loaded");
+  }
+
+  destructor() {
+    this._dialog = null;
+    this._pageTarget = null;
+
+    Services.obs.removeObserver(
+      this._onCommonDialogLoaded,
+      "common-dialog-loaded"
+    );
+    Services.obs.removeObserver(
+      this._onTabDialogLoaded,
+      "tabmodal-dialog-loaded"
+    );
+  }
+
+  async handleJavaScriptDialog({ accept, promptText }) {
+    if (!this._dialog) {
+      throw new Error("No dialog available for handleJavaScriptDialog");
+    }
+
+    const type = this._getDialogType();
+    if (promptText && type === "prompt") {
+      this._dialog.ui.loginTextbox.value = promptText;
+    }
+
+    const onDialogClosed = new Promise(r => {
+      this._browser.addEventListener("DOMModalDialogClosed", r, {
+        once: true,
+      });
+    });
+
+    // 0 corresponds to the OK callback, 1 to the CANCEL callback.
+    if (accept) {
+      this._dialog.ui.button0.click();
+    } else {
+      this._dialog.ui.button1.click();
+    }
+
+    await onDialogClosed;
+
+    // Resetting dialog to null here might be racy and lead to errors if the
+    // content page is triggering several prompts in a row.
+    // See Bug 1569578.
+    this._dialog = null;
+  }
+
+  _getDialogType() {
+    const { inPermitUnload, promptType } = this._dialog.args;
+
+    if (inPermitUnload) {
+      return DIALOG_TYPES.BEFOREUNLOAD;
+    }
+
+    switch (promptType) {
+      case "alert":
+        return DIALOG_TYPES.ALERT;
+      case "confirm":
+        return DIALOG_TYPES.CONFIRM;
+      case "prompt":
+        return DIALOG_TYPES.PROMPT;
+      default:
+        throw new Error("Unsupported dialog type: " + promptType);
+    }
+  }
+
+  _onCommonDialogLoaded(dialogWindow) {
+    const dialogs = this._browser.tabDialogBox.getContentDialogManager()
+      .dialogs;
+    const dialog = dialogs.find(d => d.frameContentWindow === dialogWindow);
+
+    if (!dialog) {
+      // The dialog is not for the current tab.
+      return;
+    }
+
+    this._dialog = dialogWindow.Dialog;
+    const message = this._dialog.args.text;
+    const type = this._getDialogType();
+
+    this.emit("dialog-loaded", { message, type });
+  }
+
+  _onTabDialogLoaded(promptContainer) {
+    const prompts = this._browser.tabModalPromptBox.listPrompts();
+    const prompt = prompts.find(p => p.ui.promptContainer === promptContainer);
+
+    if (!prompt) {
+      // The dialog is not for the current tab.
+      return;
+    }
+
+    this._dialog = prompt;
+    const message = this._dialog.args.text;
+    const type = this._getDialogType();
+
+    this.emit("dialog-loaded", { message, type });
+  }
+}