Adding upstream version 110.0.1.upstream/110.0.1upstream

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

55 files changed, 8104 insertions, 0 deletions

diff --git a/dom/chrome-webidl/BrowserSessionStore.webidl b/dom/chrome-webidl/BrowserSessionStore.webidl
new file mode 100644
index 0000000000..23d3df9457
--- /dev/null
+++ b/dom/chrome-webidl/BrowserSessionStore.webidl
@@ -0,0 +1,59 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// object contains either a CollectedFileListValue or a CollectedNonMultipleSelectValue or Sequence<DOMString>
+typedef (DOMString or boolean or object) FormDataValue;
+
+[ChromeOnly, Exposed=Window]
+interface SessionStoreFormData {
+  [Cached, Pure]
+  readonly attribute ByteString? url;
+
+  [Cached, Pure]
+  readonly attribute record<DOMString, FormDataValue>? id;
+
+  [Cached, Pure]
+  readonly attribute record<DOMString, FormDataValue>? xpath;
+
+  [Cached, Pure]
+  readonly attribute DOMString? innerHTML;
+
+  [Cached, Frozen, Pure]
+  readonly attribute sequence<SessionStoreFormData?>? children;
+
+  object toJSON();
+};
+
+[GenerateConversionToJS]
+dictionary SessionStoreDisplaySize {
+  unsigned long width;
+  unsigned long height;
+};
+
+[GenerateConversionToJS]
+dictionary SessionStoreZoomData {
+  double resolution;
+  SessionStoreDisplaySize displaySize;
+};
+
+[ChromeOnly, Exposed=Window]
+interface SessionStoreScrollData {
+  [Cached, Pure]
+  readonly attribute ByteString? scroll;
+
+  [Cached, Pure]
+  readonly attribute sequence<SessionStoreScrollData?>? children;
+
+  object toJSON();
+};
+
+[GenerateConversionToJS]
+dictionary UpdateSessionStoreData {
+  // This is docshell caps, but on-disk format uses the disallow property name.
+  ByteString? disallow;
+  boolean isPrivate;
+  SessionStoreFormData? formdata;
+  SessionStoreScrollData? scroll;
+};
diff --git a/dom/chrome-webidl/BrowsingContext.webidl b/dom/chrome-webidl/BrowsingContext.webidl
new file mode 100644
index 0000000000..590ad9e2fd
--- /dev/null
+++ b/dom/chrome-webidl/BrowsingContext.webidl
@@ -0,0 +1,394 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+interface URI;
+interface nsIDocShell;
+interface nsISecureBrowserUI;
+interface nsIPrintSettings;
+interface nsIWebProgress;
+
+interface mixin LoadContextMixin {
+  readonly attribute WindowProxy? associatedWindow;
+
+  readonly attribute WindowProxy? topWindow;
+
+  readonly attribute Element? topFrameElement;
+
+  readonly attribute boolean isContent;
+
+  [SetterThrows]
+  attribute boolean usePrivateBrowsing;
+
+  readonly attribute boolean useRemoteTabs;
+
+  readonly attribute boolean useRemoteSubframes;
+
+  [BinaryName="useTrackingProtectionWebIDL", SetterThrows]
+  attribute boolean useTrackingProtection;
+
+  [NewObject, Throws]
+  readonly attribute any originAttributes;
+};
+
+/**
+ * Allowed CSS display modes. This needs to be kept in
+ * sync with similar values in ServoStyleConsts.h
+ */
+enum DisplayMode {
+  "browser",
+  "minimal-ui",
+  "standalone",
+  "fullscreen",
+};
+
+/**
+ * CSS prefers-color-scheme values.
+ */
+enum PrefersColorSchemeOverride {
+  "none",
+  "light",
+  "dark",
+};
+
+/**
+ * Allowed overrides of platform/pref default behaviour for touch events.
+ */
+enum TouchEventsOverride {
+  "disabled", // Force-disable touch events.
+  "enabled", // Force-enable touch events.
+  "none", // Don't override behaviour for touch events.
+};
+
+[Exposed=Window, ChromeOnly]
+interface BrowsingContext {
+  static BrowsingContext? get(unsigned long long aId);
+
+  static BrowsingContext? getFromWindow(WindowProxy window);
+
+  static BrowsingContext? getCurrentTopByBrowserId(unsigned long long aId);
+
+  sequence<BrowsingContext> getAllBrowsingContextsInSubtree();
+
+  BrowsingContext? findChildWithName(DOMString name, BrowsingContext accessor);
+  BrowsingContext? findWithName(DOMString name);
+
+  readonly attribute DOMString name;
+
+  readonly attribute BrowsingContext? parent;
+
+  readonly attribute BrowsingContext top;
+
+  [Cached, Frozen, Pure]
+  readonly attribute sequence<BrowsingContext> children;
+
+  readonly attribute nsIDocShell? docShell;
+
+  readonly attribute Element? embedderElement;
+
+  readonly attribute unsigned long long id;
+
+  readonly attribute BrowsingContext? opener;
+
+  readonly attribute BrowsingContextGroup group;
+
+  readonly attribute WindowProxy? window;
+
+  readonly attribute WindowContext? currentWindowContext;
+
+  readonly attribute WindowContext? parentWindowContext;
+
+  readonly attribute WindowContext? topWindowContext;
+
+  readonly attribute boolean ancestorsAreCurrent;
+
+  [SetterThrows] attribute [LegacyNullToEmptyString] DOMString customPlatform;
+
+  [SetterThrows] attribute [LegacyNullToEmptyString] DOMString customUserAgent;
+
+  readonly attribute DOMString embedderElementType;
+
+  readonly attribute boolean createdDynamically;
+
+  readonly attribute boolean isInBFCache;
+
+  readonly attribute boolean isDiscarded;
+
+  /**
+   * The sandbox flags on the browsing context. These reflect the value of the
+   * sandbox attribute of the associated IFRAME or CSP-protectable content, if
+   * existent. See the HTML5 spec for more details.
+   * These flags on the browsing context reflect the current state of the
+   * sandbox attribute, which is modifiable. They are only used when loading new
+   * content, sandbox flags are also immutably set on the document when it is
+   * loaded.
+   * The sandbox flags of a document depend on the sandbox flags on its
+   * browsing context and of its parent document, if any.
+   * See nsSandboxFlags.h for the possible flags.
+   */
+  [SetterThrows] attribute unsigned long sandboxFlags;
+
+  [SetterThrows] attribute boolean isActive;
+
+  // The inRDMPane flag indicates whether or not Responsive Design Mode is
+  // active for the browsing context.
+  [SetterThrows] attribute boolean inRDMPane;
+
+  [SetterThrows] attribute float fullZoom;
+
+  [SetterThrows] attribute float textZoom;
+
+  // Override the dots-per-CSS-pixel scaling factor in this BrowsingContext
+  // and all of its descendants. May only be set on the top BC, and should
+  // only be set from the parent process.
+  //
+  // A value of 0.0 causes us to use the global default scaling factor.
+  //
+  // NOTE that this override only affects a few minor things (the value exposed
+  // to devicePixelRatio and some media queries in content, and responsive
+  // image selection). Most notably, it does _not_ affect rendering.
+  //
+  // It is intended for RDM, and is probably not what you want in other cases.
+  // If you want to change the actual device pixel ratio that rendering code
+  // uses, you probably want to change the fullZoom.
+  [SetterThrows] attribute float overrideDPPX;
+
+  [SetterThrows] attribute boolean suspendMediaWhenInactive;
+
+  // Default value for nsIContentViewer::authorStyleDisabled in any new
+  // browsing contexts created as a descendant of this one.
+  //
+  // Valid only for top browsing contexts.
+  [SetterThrows] attribute boolean authorStyleDisabledDefault;
+
+  /**
+   * Whether this docshell should save entries in global history.
+   */
+  [SetterThrows] attribute boolean useGlobalHistory;
+
+  // Extension to give chrome JS the ability to set the window screen
+  // orientation while in RDM.
+  [Throws] undefined setRDMPaneOrientation(OrientationType type, float rotationAngle);
+
+  // Extension to give chrome JS the ability to set a maxTouchPoints override
+  // while in RDM.
+  [Throws] undefined setRDMPaneMaxTouchPoints(octet maxTouchPoints);
+
+  // The watchedByDevTools flag indicates whether or not DevTools are currently
+  // debugging this browsing context.
+  [SetterThrows] attribute boolean watchedByDevTools;
+
+  // Enable some service workers testing features, for DevTools.
+  [SetterThrows] attribute boolean serviceWorkersTestingEnabled;
+
+  // Enable media query medium override, for DevTools.
+  [SetterThrows] attribute DOMString mediumOverride;
+
+  // Color-scheme simulation, for DevTools.
+  [SetterThrows] attribute PrefersColorSchemeOverride prefersColorSchemeOverride;
+
+  /**
+   * A unique identifier for the browser element that is hosting this
+   * BrowsingContext tree. Every BrowsingContext in the element's tree will
+   * return the same ID in all processes and it will remain stable regardless of
+   * process changes. When a browser element's frameloader is switched to
+   * another browser element this ID will remain the same but hosted under the
+   * under the new browser element.
+   */
+  [SetterThrows] attribute unsigned long long browserId;
+
+  [SetterThrows] attribute DisplayMode displayMode;
+
+  /**
+   * This allows chrome to override the default choice of whether touch events
+   * are available in a specific BrowsingContext and its descendents.
+   */
+  readonly attribute TouchEventsOverride touchEventsOverride;
+
+  /**
+   * Returns true if the top-level BrowsingContext has been configured to
+   * default-target user-initiated link clicks to _blank.
+   */
+  readonly attribute boolean targetTopLevelLinkClicksToBlank;
+
+  /**
+   * Partially determines whether script execution is allowed in this
+   * BrowsingContext. Script execution will be permitted only if this
+   * attribute is true and script execution is allowed in the parent
+   * WindowContext.
+   *
+   * May only be set in the parent process.
+   */
+  [SetterThrows] attribute boolean allowJavascript;
+
+  /**
+   * Determines whether we're forcing a desktop-mode viewport. Only settable in
+   * the top browsing context from the parent process.
+   */
+  [SetterThrows] attribute boolean forceDesktopViewport;
+
+  /*
+   * Default load flags (as defined in nsIRequest) that will be set on all
+   * requests made by this BrowsingContext.
+   */
+  [SetterThrows] attribute long defaultLoadFlags;
+
+  /**
+   * The nsID of the browsing context in the session history.
+   */
+  [NewObject, Throws]
+  readonly attribute any historyID;
+
+  readonly attribute ChildSHistory? childSessionHistory;
+
+  // Resets the location change rate limit. Used for testing.
+  undefined resetLocationChangeRateLimit();
+
+  readonly attribute long childOffset;
+};
+
+BrowsingContext includes LoadContextMixin;
+
+[Exposed=Window, ChromeOnly]
+interface CanonicalBrowsingContext : BrowsingContext {
+  sequence<WindowGlobalParent> getWindowGlobals();
+
+  readonly attribute WindowGlobalParent? currentWindowGlobal;
+
+  readonly attribute WindowProxy? topChromeWindow;
+
+  // XXX(nika): This feels kinda hacky, but will do for now while we don't
+  // synchronously create WindowGlobalParent. It can throw if somehow the
+  // content process has died.
+  [Throws]
+  readonly attribute UTF8String? currentRemoteType;
+
+  readonly attribute WindowGlobalParent? embedderWindowGlobal;
+
+  undefined notifyStartDelayedAutoplayMedia();
+  [Throws] undefined notifyMediaMutedChanged(boolean muted);
+
+  readonly attribute nsISecureBrowserUI? secureBrowserUI;
+
+  /**
+   * Returns an nsIWebProgress object for this BrowsingContext, if this
+   * is a top-level content BC.
+   *
+   * Progress listeners attached to this will get notifications filtered by
+   * nsBrowserStatusFilter, and don't get any notifications from sub frames.
+   */
+  readonly attribute nsIWebProgress? webProgress;
+
+  static unsigned long countSiteOrigins(sequence<BrowsingContext> roots);
+
+  /**
+   * Loads a given URI.  This will give priority to loading the requested URI
+   * in the object implementing this interface.  If it can't be loaded here
+   * however, the URI dispatcher will go through its normal process of content
+   * loading.
+   *
+   * @param aURI
+   *        The URI string to load.  For HTTP and FTP URLs and possibly others,
+   *        characters above U+007F will be converted to UTF-8 and then URL-
+   *        escaped per the rules of RFC 2396.
+   * @param aLoadURIOptions
+   *        A JSObject defined in LoadURIOptions.webidl holding info like e.g.
+   *        the triggeringPrincipal, the referrer info.
+   */
+  [Throws]
+  undefined loadURI(DOMString aURI, optional LoadURIOptions aOptions = {});
+
+   /**
+    * Print the current document.
+    *
+    * @param aOuterWindowID the ID of the outer window to print
+    * @param aPrintSettings print settings to use; printSilent can be
+    *                       set to prevent prompting.
+    * @return A Promise that resolves once printing is finished.
+    */
+  [NewObject, BinaryName="printJS"]
+  Promise<undefined> print(nsIPrintSettings aPrintSettings);
+
+  /**
+   * These methods implement the nsIWebNavigation methods of the same names
+   */
+  undefined goBack(optional long aCancelContentJSEpoch, optional boolean aRequireUserInteraction = false, optional boolean aUserActivation = false);
+  undefined goForward(optional long aCancelContentJSEpoch, optional boolean aRequireUserInteraction  = false, optional boolean aUserActivation = false);
+  undefined goToIndex(long aIndex, optional long aCancelContentJSEpoch, optional boolean aUserActivation = false);
+  undefined reload(unsigned long aReloadFlags);
+  undefined stop(unsigned long aStopFlags);
+
+  readonly attribute nsISHistory? sessionHistory;
+
+  readonly attribute MediaController? mediaController;
+
+  undefined resetScalingZoom();
+
+  // The current URI loaded in this BrowsingContext according to nsDocShell.
+  // This may not match the current window global's document URI in some cases.
+  readonly attribute URI? currentURI;
+
+  undefined clearRestoreState();
+
+  // Force this browsing context, which must correspond to an app window, to
+  // be active regardless of the window being minimized or fully occluded.
+  [SetterThrows] attribute boolean forceAppWindowActive;
+
+  /**
+   * This allows chrome to override the default choice of whether touch events
+   * are available in a specific BrowsingContext and its descendents.
+   */
+  [SetterThrows] inherit attribute TouchEventsOverride touchEventsOverride;
+
+  /**
+   * Set to true to configure the top-level BrowsingContext to default-target
+   * user-initiated link clicks to _blank.
+   */
+  [SetterThrows] inherit attribute boolean targetTopLevelLinkClicksToBlank;
+
+  /**
+   * Set the cross-group opener of this BrowsingContext. This is used to
+   * retarget the download dialog to an opener window, and close this
+   * BrowsingContext, if the first load in a newly created BrowsingContext is a
+   * download.
+   *
+   * This value will be automatically set for documents created using
+   * `window.open`.
+   */
+  [Throws]
+  undefined setCrossGroupOpener(CanonicalBrowsingContext crossGroupOpener);
+
+  readonly attribute boolean isReplaced;
+
+
+  /**
+   * Notify APZ to start autoscrolling.
+   *
+   * (aAnchorX, aAnchorY) are the coordinates of the autoscroll anchor, in
+   *                      device coordinates relative to the screen.
+   * aScrollId and aPresShellId identify the scroll frame that content chose to
+   *                            scroll.
+   *
+   * Returns whether we were successfully able to notify APZ.
+   * If this function returns true, APZ (which may live in another process) may
+   * still reject the autoscroll, but it's then APZ's responsibility to notify
+   * content via an "autoscroll-rejected-by-apz" message.
+   */
+  boolean startApzAutoscroll(float aAnchorX, float aAnchorY,
+                             unsigned long long aScrollId,
+                             unsigned long aPresShellId);
+
+  /**
+   * Notify APZ to stop autoscrolling.
+   */
+  undefined stopApzAutoscroll(unsigned long long aScrollId,
+                              unsigned long aPresShellId);
+};
+
+[Exposed=Window, ChromeOnly]
+interface BrowsingContextGroup {
+  sequence<BrowsingContext> getToplevels();
+
+  readonly attribute unsigned long long id;
+};
diff --git a/dom/chrome-webidl/ChannelWrapper.webidl b/dom/chrome-webidl/ChannelWrapper.webidl
new file mode 100644
index 0000000000..b932e79c76
--- /dev/null
+++ b/dom/chrome-webidl/ChannelWrapper.webidl
@@ -0,0 +1,578 @@
+/* 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/. */
+
+interface LoadInfo;
+interface MozChannel;
+interface RemoteTab;
+interface URI;
+interface nsISupports;
+
+/**
+ * Load types that correspond to the external types in nsIContentPolicy.idl.
+ * Please also update that IDL when updating this list.
+ */
+enum MozContentPolicyType {
+  "main_frame",
+  "sub_frame",
+  "stylesheet",
+  "script",
+  "image",
+  "object",
+  "object_subrequest",
+  "xmlhttprequest",
+  "fetch",
+  "xslt",
+  "ping",
+  "beacon",
+  "xml_dtd",
+  "font",
+  "media",
+  "websocket",
+  "csp_report",
+  "imageset",
+  "web_manifest",
+  "speculative",
+  "other"
+};
+
+/**
+ * String versions of CLASSIFIED_* tracking flags from nsIClassifiedChannel.idl
+ */
+enum MozUrlClassificationFlags {
+  "fingerprinting",
+  "fingerprinting_content",
+  "cryptomining",
+  "cryptomining_content",
+  "emailtracking",
+  "emailtracking_content",
+  "tracking",
+  "tracking_ad",
+  "tracking_analytics",
+  "tracking_social",
+  "tracking_content",
+  "socialtracking",
+  "socialtracking_facebook",
+  "socialtracking_linkedin",
+  "socialtracking_twitter",
+  "any_basic_tracking",
+  "any_strict_tracking",
+  "any_social_tracking"
+};
+
+/**
+ * A thin wrapper around nsIChannel and nsIHttpChannel that allows JS
+ * callers to access them without XPConnect overhead.
+ */
+[ChromeOnly, Exposed=Window]
+interface ChannelWrapper : EventTarget {
+  /**
+   * Returns the wrapper instance for the given channel. The same wrapper is
+   * always returned for a given channel.
+   */
+  static ChannelWrapper get(MozChannel channel);
+
+  /**
+   * Returns the wrapper instance for the given channel. The same wrapper is
+   * always returned for a given channel.
+   */
+  static ChannelWrapper? getRegisteredChannel(unsigned long long aChannelId,
+                                             WebExtensionPolicy extension,
+                                             RemoteTab? remoteTab);
+
+  /**
+   * A unique ID for for the requests which remains constant throughout the
+   * redirect chain.
+   */
+  [Constant, StoreInSlot]
+  readonly attribute unsigned long long id;
+
+  // Not technically pure, since it's backed by a weak reference, but if JS
+  // has a reference to the previous value, we can depend on it not being
+  // collected.
+  [Pure]
+  attribute MozChannel? channel;
+
+
+  /**
+   * Cancels the request with the given nsresult status code.
+   *
+   * The optional reason parameter should be one of the BLOCKING_REASON
+   * constants from nsILoadInfo.idl
+   */
+  [Throws]
+  undefined cancel(unsigned long result, optional unsigned long reason = 0);
+
+  /**
+   * Redirects the wrapped HTTP channel to the given URI. For other channel
+   * types, this method will throw. The redirect is an internal redirect, and
+   * the behavior is the same as nsIHttpChannel.redirectTo.
+   */
+  [Throws]
+  undefined redirectTo(URI url);
+
+  /**
+   * Requests an upgrade of the HTTP channel to a secure request. For other channel
+   * types, this method will throw. The redirect is an internal redirect, and
+   * the behavior is the same as nsIHttpChannel.upgradeToSecure. Setting this
+   * flag is only effective during the WebRequest.onBeforeRequest in
+   * Web Extensions, calling this at any other point during the request will
+   * have no effect. Setting this flag in addition to calling redirectTo
+   * results in the redirect happening rather than the upgrade request.
+   */
+  [Throws]
+  undefined upgradeToSecure();
+
+  /**
+   * Suspends the underlying channel.  The profilerText parameter is only used
+   * to annotate profiles.
+   */
+  [Throws]
+  undefined suspend(ByteString profileMarkerText);
+
+  /**
+   * Resumes (un-suspends) the underlying channel.
+   */
+  [Throws]
+  undefined resume();
+
+  /**
+   * The content type of the request, usually as read from the Content-Type
+   * header. This should be used in preference to the header to determine the
+   * content type of the channel.
+   */
+  [Pure]
+  attribute ByteString contentType;
+
+
+  /**
+   * For HTTP requests, the request method (e.g., GET, POST, HEAD). For other
+   * request types, returns an empty string.
+   */
+  [Cached, Pure]
+  readonly attribute ByteString method;
+
+  /**
+   * For requests with LoadInfo, the content policy type that corresponds to
+   * the request. For requests without LoadInfo, returns "other".
+   */
+  [Cached, Pure]
+  readonly attribute MozContentPolicyType type;
+
+
+  /**
+   * When true, the request is currently suspended by the wrapper. When false,
+   * the request is not suspended by the wrapper, but may still be suspended
+   * by another caller.
+   */
+  [Pure]
+  readonly attribute boolean suspended;
+
+
+  /**
+   * The final URI of the channel (as returned by NS_GetFinalChannelURI) after
+   * any redirects have been processed.
+   */
+  [Cached, Pure]
+  readonly attribute URI finalURI;
+
+  /**
+   * The string version of finalURI (but cheaper to access than
+   * finalURI.spec).
+   */
+  [Cached, Pure]
+  readonly attribute DOMString finalURL;
+
+
+  /**
+   * Returns true if the request matches the given request filter, and the
+   * given extension has permission to access it.
+   */
+  boolean matches(optional MozRequestFilter filter = {},
+                  optional WebExtensionPolicy? extension = null,
+                  optional MozRequestMatchOptions options = {});
+
+
+  /**
+   * Register's this channel as traceable by the given add-on when accessed
+   * via the process of the given RemoteTab.
+   */
+  undefined registerTraceableChannel(WebExtensionPolicy extension, RemoteTab? remoteTab);
+
+  /**
+   * The current HTTP status code of the request. This will be 0 if a response
+   * has not yet been received, or if the request is not an HTTP request.
+   */
+  [Cached, Pure]
+  readonly attribute unsigned long statusCode;
+
+  /**
+   * The HTTP status line for the request (e.g., "HTTP/1.0 200 Success"). This
+   * will be an empty string if a response has not yet been received, or if
+   * the request is not an HTTP request.
+   */
+  [Cached, Pure]
+  readonly attribute ByteString statusLine;
+
+
+  /**
+   * If the request has failed or been canceled, an opaque string representing
+   * the error. For requests that failed at the NSS layer, this is an NSS
+   * error message. For requests that failed for any other reason, it is the
+   * name of an nsresult error code. For requests which haven't failed, this
+   * is null.
+   *
+   * This string is used in the error message when notifying extension
+   * webRequest listeners of failure. The documentation specifically states
+   * that this value MUST NOT be parsed, and is only meant to be displayed to
+   * humans, but we all know how that works in real life.
+   */
+  [Cached, Pure]
+  readonly attribute DOMString? errorString;
+
+  /**
+   * Dispatched when the channel is closed with an error status. Check
+   * errorString for the error details.
+   */
+  attribute EventHandler onerror;
+
+  /**
+   * Checks the request's current status and dispatches an error event if the
+   * request has failed and one has not already been dispatched.
+   */
+  undefined errorCheck();
+
+
+  /**
+   * Dispatched when the channel begins receiving data.
+   */
+  attribute EventHandler onstart;
+
+  /**
+   * Dispatched when the channel has finished receiving data.
+   */
+  attribute EventHandler onstop;
+
+
+  /**
+   * Information about the proxy server which is handling this request, or
+   * null if the request is not proxied.
+   */
+  [Cached, Frozen, GetterThrows, Pure]
+  readonly attribute MozProxyInfo? proxyInfo;
+
+  /**
+   * For HTTP requests, the IP address of the remote server handling the
+   * request. For other request types, returns null.
+   */
+  [Cached, Pure]
+  readonly attribute ByteString? remoteAddress;
+
+
+  /**
+   * The LoadInfo object for this channel, if available. Null for channels
+   * without load info, until support for those is removed.
+   */
+  [Cached, Pure]
+  readonly attribute LoadInfo? loadInfo;
+
+  /**
+   * True if this load for a service worker script (either a main script or import scripts).
+   */
+  [Cached, Pure]
+  readonly attribute boolean isServiceWorkerScript;
+
+  /**
+   * True if this load was triggered by a system caller. This currently always
+   * false if the request has no LoadInfo or is a top-level document load.
+   */
+  [Cached, Pure]
+  readonly attribute boolean isSystemLoad;
+
+  /**
+   * The URL of the principal that triggered this load. This is equivalent to
+   * the LoadInfo's triggeringPrincipal, and will only ever be null for
+   * requests without LoadInfo.
+   */
+  [Cached, Pure]
+  readonly attribute ByteString? originURL;
+
+  /**
+   * The URL of the document loading the content for this request. This is
+   * equivalent to the LoadInfo's loadingPrincipal. This may only ever be null
+   * for top-level requests and requests without LoadInfo.
+   */
+  [Cached, Pure]
+  readonly attribute ByteString? documentURL;
+
+  /**
+   * The URI version of originURL. Will be null only when originURL is null.
+   */
+  [Pure]
+  readonly attribute URI? originURI;
+
+  /**
+   * The URI version of documentURL. Will be null only when documentURL is
+   * null.
+   */
+  [Pure]
+  readonly attribute URI? documentURI;
+
+
+  /**
+   * True if extensions may modify this request. This is currently false only
+   * if the request belongs to a document which has access to the
+   * mozAddonManager API.
+   */
+  [Cached, GetterThrows, Pure]
+  readonly attribute boolean canModify;
+
+
+  /**
+   * The BrowsingContext ID of the frame that the request belongs to, or 0 if it
+   * is a top-level load or does not belong to a document.
+   */
+  [Cached, Constant]
+  readonly attribute long long frameId;
+
+  /**
+   * The BrowsingContext ID of the parent frame of the window that the request
+   * belongs to, 0 if that parent frame is the top-level frame, and -1 if the
+   * request belongs to a top-level frame.
+   */
+  [Cached, Constant]
+  readonly attribute long long parentFrameId;
+
+  /**
+   * For cross-process requests, the <browser> or <iframe> element to which the
+   * content loading this request belongs. For requests that don't originate
+   * from a remote browser, this is null.
+   *
+   * This is not an Element because those are by default only exposed in
+   * Window, but we're exposed in System.
+   */
+  [Cached, Pure]
+  readonly attribute nsISupports? browserElement;
+
+  /**
+   * Returns an array of objects that combine the url and frameId from the
+   * ancestorPrincipals and ancestorOuterWindowIDs on loadInfo.
+   * The immediate parent is the first entry, the last entry is always the top
+   * level frame.  It will be an empty list for toplevel window loads and
+   * non-subdocument resource loads within a toplevel window.  For the latter,
+   * originURL will provide information on what window is doing the load.  It
+   * will be null if the request is not associated with a window (e.g. XHR with
+   * mozBackgroundRequest = true).
+   */
+  [Cached, Frozen, GetterThrows, Pure]
+  readonly attribute sequence<MozFrameAncestorInfo>? frameAncestors;
+
+  /**
+   * For HTTP requests, returns an array of request headers which will be, or
+   * have been, sent with this request.
+   *
+   * For non-HTTP requests, throws NS_ERROR_UNEXPECTED.
+   */
+  [Throws]
+  sequence<MozHTTPHeader> getRequestHeaders();
+
+  /**
+  * For HTTP requests: returns the value of the request header, null if not set.
+  *
+  * For non-HTTP requests, throws NS_ERROR_UNEXPECTED.
+  */
+  [Throws]
+  ByteString? getRequestHeader(ByteString header);
+
+  /**
+   * For HTTP requests, returns an array of response headers which were
+   * received for this request, in the same format as returned by
+   * getRequestHeaders.
+
+   * Throws NS_ERROR_NOT_AVAILABLE if a response has not yet been received, or
+   * NS_ERROR_UNEXPECTED if the channel is not an HTTP channel.
+   *
+   * Note: The Content-Type header is handled specially. That header is
+   * usually not mutable after the request has been received, and the content
+   * type must instead be changed via the contentType attribute. If a caller
+   * attempts to set the Content-Type header via setRequestHeader, however,
+   * that value is assigned to the contentType attribute and its original
+   * string value is cached. That original value is returned in place of the
+   * actual Content-Type header.
+   */
+  [Throws]
+  sequence<MozHTTPHeader> getResponseHeaders();
+
+  /**
+   * Sets the given request header to the given value, overwriting any
+   * previous value. Setting a header to a null string has the effect of
+   * removing it.  If merge is true, then the passed value will be merged
+   * to any existing value that exists for the header. Otherwise, any prior
+   * value for the header will be overwritten. Merge is ignored for headers
+   * that cannot be merged.
+   *
+   * For non-HTTP requests, throws NS_ERROR_UNEXPECTED.
+   */
+  [Throws]
+  undefined setRequestHeader(ByteString header,
+                        ByteString value,
+                        optional boolean merge = false);
+
+  /**
+   * Sets the given response header to the given value, overwriting any
+   * previous value. Setting a header to a null string has the effect of
+   * removing it.  If merge is true, then the passed value will be merged
+   * to any existing value that exists for the header (e.g. handling multiple
+   * Set-Cookie headers).  Otherwise, any prior value for the header will be
+   * overwritten. Merge is ignored for headers that cannot be merged.
+   *
+   * For non-HTTP requests, throws NS_ERROR_UNEXPECTED.
+   *
+   * Note: The content type header is handled specially by this function. See
+   * getResponseHeaders() for details.
+   */
+  [Throws]
+  undefined setResponseHeader(ByteString header,
+                         ByteString value,
+                         optional boolean merge = false);
+
+  /**
+   * Provides the tracking classification data when it is available.
+   */
+  [Cached, Frozen, GetterThrows, Pure]
+  readonly attribute MozUrlClassification? urlClassification;
+
+  /**
+   * Indicates if this response and its content window hierarchy is third
+   * party.
+   */
+  [Cached, Constant]
+  readonly attribute boolean thirdParty;
+
+  /**
+   * The current bytes sent of the request. This will be 0 if a request has not
+   * sent yet, or if the request is not an HTTP request.
+   */
+  [Cached, Pure]
+  readonly attribute unsigned long long requestSize;
+
+  /**
+   * The current bytes received of the response. This will be 0 if a response
+   * has not recieved yet, or if the request is not an HTTP response.
+   */
+  [Cached, Pure]
+  readonly attribute unsigned long long responseSize;
+};
+
+/**
+ * Wrapper for first and third party tracking classification data.
+ */
+dictionary MozUrlClassification {
+  required sequence<MozUrlClassificationFlags> firstParty;
+  required sequence<MozUrlClassificationFlags> thirdParty;
+};
+
+/**
+ * Information about the proxy server handing a request. This is approximately
+ * equivalent to nsIProxyInfo.
+ */
+dictionary MozProxyInfo {
+  /**
+   * The hostname of the server.
+   */
+  required ByteString host;
+  /**
+   * The TCP port of the server.
+   */
+  required long port;
+  /**
+   * The type of proxy (e.g., HTTP, SOCKS).
+   */
+  required ByteString type;
+
+  /**
+   * True if the proxy is responsible for DNS lookups.
+   */
+  required boolean proxyDNS;
+
+  /**
+   * The authentication username for the proxy, if any.
+   */
+  ByteString? username = null;
+
+  /**
+   * The timeout, in seconds, before the network stack will failover to the
+   * next candidate proxy server if it has not received a response.
+   */
+  unsigned long failoverTimeout;
+
+  /**
+   * Any non-empty value will be passed directly as Proxy-Authorization header
+   * value for the CONNECT request attempt.  However, this header set on the
+   * resource request itself takes precedence.
+   */
+  ByteString? proxyAuthorizationHeader = null;
+
+  /**
+   * An optional key used for additional isolation of this proxy connection.
+   */
+  ByteString? connectionIsolationKey = null;
+};
+
+/**
+ * MozFrameAncestorInfo combines loadInfo::AncestorPrincipals with
+ * loadInfo::AncestorOuterWindowIDs for easier access in the WebRequest API.
+ *
+ * url represents the parent of the loading window.
+ * frameId is the outerWindowID for the parent of the loading window.
+ *
+ * For further details see nsILoadInfo.idl and Document::AncestorPrincipals.
+ */
+dictionary MozFrameAncestorInfo {
+  required ByteString url;
+  required unsigned long long frameId;
+};
+
+/**
+ * Represents an HTTP request or response header.
+ */
+dictionary MozHTTPHeader {
+  /**
+   * The case-insensitive, non-case-normalized header name.
+   */
+  required ByteString name;
+  /**
+   * The header value.
+   */
+  required ByteString value;
+};
+
+/**
+ * An object used for filtering requests.
+ */
+dictionary MozRequestFilter {
+  /**
+   * If present, the request only matches if its `type` attribute matches one
+   * of the given types.
+   */
+  sequence<MozContentPolicyType>? types = null;
+
+  /**
+   * If present, the request only matches if its finalURI matches the given
+   * match pattern set.
+   */
+  MatchPatternSet? urls = null;
+
+  /**
+   * If present, the request only matches if the loadInfo privateBrowsingId matches
+   * against the given incognito value.
+   */
+  boolean? incognito = null;
+};
+
+dictionary MozRequestMatchOptions {
+  /**
+   * True if we're matching for the proxy portion of a proxied request.
+   */
+  boolean isProxy = false;
+};
diff --git a/dom/chrome-webidl/ChromeUtils.webidl b/dom/chrome-webidl/ChromeUtils.webidl
new file mode 100644
index 0000000000..f8f0b02ee7
--- /dev/null
+++ b/dom/chrome-webidl/ChromeUtils.webidl
@@ -0,0 +1,1009 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface nsIDOMProcessChild;
+interface nsIDOMProcessParent;
+interface Principal;
+
+/**
+ * An optimized QueryInterface method, generated by generateQI.
+ *
+ * For JS callers, this behaves like a normal QueryInterface function. When
+ * called with a supported interface, it returns its `this` object. When
+ * called with an unsupported interface, it throws NS_ERROR_NO_INTERFACE.
+ *
+ * C++ callers use a fast path, and never call the JSAPI or WebIDL methods of
+ * this object.
+ */
+[ChromeOnly, Exposed=Window]
+interface MozQueryInterface {
+  [Throws]
+  legacycaller any (any aIID);
+};
+
+/**
+ * Options for a marker created with the addProfilerMarker method.
+ * All fields are optional.
+ */
+dictionary ProfilerMarkerOptions {
+  // A timestamp to use as the start time of the marker.
+  // If no start time is provided, the marker will have no duration.
+  // In window and ChromeWorker contexts, use a timestamp from
+  // `performance.now()`.
+  // In JS modules, use `Cu.now()` to get a timestamp.
+  DOMHighResTimeStamp startTime = 0;
+
+  // If captureStack is true, a profiler stack will be captured and associated
+  // with the marker.
+  boolean captureStack = false;
+
+  // Markers are created by default in the JavaScript category, but this can be
+  // overridden.
+  // Examples of correct values: "JavaScript", "Test", "Other", ...
+  // See ProfilingCategoryList.h for the complete list of valid values.
+  // Using an unrecognized value will set the category to "Other".
+  ByteString category = "JavaScript";
+
+  // Inner window ID to use for the marker. If the global object is a window,
+  // the inner window id of the marker will be set automatically.
+  // If a marker that relates to a specific window is added from a JS module,
+  // setting the inner window id will allow the profiler to show which window
+  // the marker applies to.
+  unsigned long long innerWindowId = 0;
+};
+
+dictionary InteractionData {
+  unsigned long interactionCount = 0;
+  unsigned long interactionTimeInMilliseconds = 0;
+  unsigned long scrollingDistanceInPixels = 0;
+};
+
+/**
+ * Confidence value of credit card fields. This is used by the native
+ * Fathom Credit Card model to return the score to JS.
+ */
+dictionary FormAutofillConfidences {
+  double ccNumber = 0;
+  double ccName = 0;
+};
+
+/**
+ * A collection of static utility methods that are only exposed to system code.
+ * This is exposed in all the system globals where we can expose stuff by
+ * default, so should only include methods that are **thread-safe**.
+ */
+[ChromeOnly, Exposed=(Window,Worker)]
+namespace ChromeUtils {
+  /**
+   * Get the |NodeId| for the given JS Object.
+   * |NodeId| is the identifier of |JS::ubi::Node|.
+   */
+  NodeId getObjectNodeId(object obj);
+
+  /**
+   * Serialize a snapshot of the heap graph, as seen by |JS::ubi::Node| and
+   * restricted by |boundaries|, and write it to the provided file path.
+   *
+   * @param boundaries        The portion of the heap graph to write.
+   *
+   * @returns                 The path to the file the heap snapshot was written
+   *                          to. This is guaranteed to be within the temp
+   *                          directory and its file name will match the regexp
+   *                          `\d+(\-\d+)?\.fxsnapshot`.
+   */
+  [Throws]
+  DOMString saveHeapSnapshot(optional HeapSnapshotBoundaries boundaries = {});
+
+  /**
+   * This is the same as saveHeapSnapshot, but with a different return value.
+   *
+   * @returns                 The snapshot ID of the file. This is the file name
+   *                          without the temp directory or the trailing
+   *                          `.fxsnapshot`.
+   */
+  [Throws]
+  DOMString saveHeapSnapshotGetId(optional HeapSnapshotBoundaries boundaries = {});
+
+  /**
+   * Deserialize a core dump into a HeapSnapshot.
+   *
+   * @param filePath          The file path to read the heap snapshot from.
+   */
+  [Throws, NewObject]
+  HeapSnapshot readHeapSnapshot(DOMString filePath);
+
+  /**
+   * Return the keys in a weak map.  This operation is
+   * non-deterministic because it is affected by the scheduling of the
+   * garbage collector and the cycle collector.
+   *
+   * @param aMap weak map or other JavaScript value
+   * @returns If aMap is a weak map object, return the keys of the weak
+   *          map as an array.  Otherwise, return undefined.
+   */
+  [Throws, NewObject]
+  any nondeterministicGetWeakMapKeys(any map);
+
+  /**
+   * Return the keys in a weak set.  This operation is
+   * non-deterministic because it is affected by the scheduling of the
+   * garbage collector and the cycle collector.
+   *
+   * @param aSet weak set or other JavaScript value
+   * @returns If aSet is a weak set object, return the keys of the weak
+   *          set as an array.  Otherwise, return undefined.
+   */
+  [Throws, NewObject]
+  any nondeterministicGetWeakSetKeys(any aSet);
+
+  /**
+   * Converts a buffer to a Base64 URL-encoded string per RFC 4648.
+   *
+   * @param source The buffer to encode.
+   * @param options Additional encoding options.
+   * @returns The encoded string.
+   */
+  [Throws]
+  ByteString base64URLEncode(BufferSource source,
+                             Base64URLEncodeOptions options);
+
+  /**
+   * Decodes a Base64 URL-encoded string per RFC 4648.
+   *
+   * @param string The string to decode.
+   * @param options Additional decoding options.
+   * @returns The decoded buffer.
+   */
+  [Throws, NewObject]
+  ArrayBuffer base64URLDecode(ByteString string,
+                              Base64URLDecodeOptions options);
+
+  /**
+   * Cause the current process to fatally crash unless the given condition is
+   * true. This is similar to MOZ_RELEASE_ASSERT in C++ code.
+   *
+   * WARNING: This message is included publicly in the crash report, and must
+   * not contain private information.
+   *
+   * Crash report will be augmented with the current JS stack information.
+   */
+  undefined releaseAssert(boolean condition,
+                          optional DOMString message = "<no message>");
+
+#ifdef NIGHTLY_BUILD
+
+  /**
+   * If the chrome code has thrown a JavaScript Dev Error
+   * in the current JSRuntime. the first such error, or `undefined`
+   * otherwise.
+   *
+   * A JavaScript Dev Error is an exception thrown by JavaScript
+   * code that matches both conditions:
+   * - it was thrown by chrome code;
+   * - it is either a `ReferenceError`, a `TypeError` or a `SyntaxError`.
+   *
+   * Such errors are stored regardless of whether they have been
+   * caught.
+   *
+   * This mechanism is designed to help ensure that the code of
+   * Firefox is free from Dev Errors, even if they are accidentally
+   * caught by clients.
+   *
+   * The object returned is not an exception. It has fields:
+   * - DOMString stack
+   * - DOMString filename
+   * - DOMString lineNumber
+   * - DOMString message
+   */
+  [Throws]
+  readonly attribute any recentJSDevError;
+
+  /**
+   * Reset `recentJSDevError` to `undefined` for the current JSRuntime.
+   */
+  undefined clearRecentJSDevError();
+#endif // NIGHTLY_BUILD
+
+  /**
+   * Clears the stylesheet cache by baseDomain. This includes associated
+   * state-partitioned cache.
+   */
+  undefined clearStyleSheetCacheByBaseDomain(UTF8String baseDomain);
+
+  /**
+   * Clears the stylesheet cache by principal.
+   */
+  undefined clearStyleSheetCacheByPrincipal(Principal principal);
+
+  /**
+   * Clears the entire stylesheet cache.
+   */
+  undefined clearStyleSheetCache();
+
+  /**
+   * If the profiler is currently running and recording the current thread,
+   * add a marker for the current thread. No-op otherwise.
+   *
+   * @param name              The name of the marker.
+   * @param options           Either a timestamp to use as the start time of the
+   *                          marker, or a ProfilerMarkerOptions object that can
+   *                          contain startTime, captureStack or category fields.
+   *                          If this parameter is omitted, the marker will have
+   *                           no duration.
+   *                          In window and ChromeWorker contexts, use a
+   *                          timestamp from `performance.now()`.
+   *                          In JS modules, use `Cu.now()` to get a timestamp.
+   * @param text              Text to associate with the marker.
+   */
+  undefined addProfilerMarker(UTF8String name,
+                              optional (ProfilerMarkerOptions or DOMHighResTimeStamp) options = {},
+                              optional UTF8String text);
+
+  /**
+   * Return the symbolic name of any given XPCOM error code (nsresult):
+   * "NS_OK", "NS_ERROR_FAILURE",...
+   */
+  UTF8String getXPCOMErrorName(unsigned long aErrorCode);
+
+  /**
+   * Return a fractional number representing the current time (in milliseconds from the Epoch).
+   * Should be JS_Now()/1000 so that it can be compared to Date.now in Javascript.
+   */
+  double dateNow();
+
+  /**
+   * IF YOU ADD NEW METHODS HERE, MAKE SURE THEY ARE THREAD-SAFE.
+   */
+};
+
+/**
+ * Additional ChromeUtils methods that are _not_ thread-safe, and hence not
+ * exposed in workers.
+ */
+[Exposed=Window]
+partial namespace ChromeUtils {
+  /**
+   * A helper that converts OriginAttributesDictionary to a opaque suffix string.
+   *
+   * @param originAttrs       The originAttributes from the caller.
+   */
+  ByteString
+  originAttributesToSuffix(optional OriginAttributesDictionary originAttrs = {});
+
+  /**
+   * Returns true if the members of |originAttrs| match the provided members
+   * of |pattern|.
+   *
+   * @param originAttrs       The originAttributes under consideration.
+   * @param pattern           The pattern to use for matching.
+   */
+  boolean
+  originAttributesMatchPattern(optional OriginAttributesDictionary originAttrs = {},
+                               optional OriginAttributesPatternDictionary pattern = {});
+
+  /**
+   * Returns an OriginAttributesDictionary with values from the |origin| suffix
+   * and unspecified attributes added and assigned default values.
+   *
+   * @param origin            The origin URI to create from.
+   * @returns                 An OriginAttributesDictionary with values from
+   *                          the origin suffix and unspecified attributes
+   *                          added and assigned default values.
+   */
+  [Throws]
+  OriginAttributesDictionary
+  createOriginAttributesFromOrigin(DOMString origin);
+
+  /**
+   * Returns an OriginAttributesDictionary with values from the origin |suffix|
+   * and unspecified attributes added and assigned default values.
+   *
+   * @param suffix            The origin suffix to create from.
+   * @returns                 An OriginAttributesDictionary with values from
+   *                          the origin suffix and unspecified attributes
+   *                          added and assigned default values.
+   */
+  [Throws]
+  OriginAttributesDictionary
+  CreateOriginAttributesFromOriginSuffix(DOMString suffix);
+
+  /**
+   * Returns an OriginAttributesDictionary that is a copy of |originAttrs| with
+   * unspecified attributes added and assigned default values.
+   *
+   * @param originAttrs       The origin attributes to copy.
+   * @returns                 An OriginAttributesDictionary copy of |originAttrs|
+   *                          with unspecified attributes added and assigned
+   *                          default values.
+   */
+  OriginAttributesDictionary
+  fillNonDefaultOriginAttributes(optional OriginAttributesDictionary originAttrs = {});
+
+  /**
+   * Returns true if the 2 OriginAttributes are equal.
+   */
+  boolean
+  isOriginAttributesEqual(optional OriginAttributesDictionary aA = {},
+                          optional OriginAttributesDictionary aB = {});
+
+  /**
+   * Returns the base domain portion of a given partitionKey.
+   * Returns the empty string for an empty partitionKey.
+   * Throws for invalid partition keys.
+   */
+  [Throws]
+  DOMString
+  getBaseDomainFromPartitionKey(DOMString partitionKey);
+
+  /**
+   * Returns the partitionKey for a given URL.
+   *
+   * The function will treat the URL as a first party and construct the
+   * partitionKey according to the scheme, site and port in the URL.
+   *
+   * Throws for invalid urls.
+   */
+  [Throws]
+  DOMString
+  getPartitionKeyFromURL(DOMString url);
+
+  /**
+   * Loads and compiles the script at the given URL and returns an object
+   * which may be used to execute it repeatedly, in different globals, without
+   * re-parsing.
+   */
+  [NewObject]
+  Promise<PrecompiledScript>
+  compileScript(DOMString url, optional CompileScriptOptionsDictionary options = {});
+
+  /**
+   * Returns an optimized QueryInterface method which, when called from
+   * JavaScript, acts as an ordinary QueryInterface function call, and when
+   * called from XPConnect, circumvents JSAPI entirely.
+   *
+   * The list of interfaces may include a mix of JS ID objects and interface
+   * name strings.
+   *
+   * nsISupports is implicitly supported, and must not be included in the
+   * interface list.
+   */
+  [Affects=Nothing, NewObject, Throws]
+  MozQueryInterface generateQI(sequence<any> interfaces);
+
+  /**
+   * Waive Xray on a given value. Identity op for primitives.
+   */
+  [Throws]
+  any waiveXrays(any val);
+
+  /**
+   * Strip off Xray waivers on a given value. Identity op for primitives.
+   */
+  [Throws]
+  any unwaiveXrays(any val);
+
+  /**
+   * Gets the name of the JSClass of the object.
+   *
+   * if |unwrap| is true, all wrappers are unwrapped first. Unless you're
+   * specifically trying to detect whether the object is a proxy, this is
+   * probably what you want.
+   */
+  DOMString getClassName(object obj, optional boolean unwrap = true);
+
+  /**
+   * Returns whether the object is a DOM object.
+   *
+   * if |unwrap| is true, all wrappers are unwrapped first. Unless you're
+   * specifically trying to detect whether the object is a proxy, this is
+   * probably what you want.
+   */
+  boolean isDOMObject(object obj, optional boolean unwrap = true);
+
+  /**
+   * Clones the properties of the given object into a new object in the given
+   * target compartment (or the caller compartment if no target is provided).
+   * Property values themeselves are not cloned.
+   *
+   * Ignores non-enumerable properties, properties on prototypes, and properties
+   * with getters or setters.
+   */
+  [Throws]
+  object shallowClone(object obj, optional object? target = null);
+
+  /**
+   * Dispatches the given callback to the main thread when it would be
+   * otherwise idle. Similar to Window.requestIdleCallback, but not bound to a
+   * particular DOM windw.
+   */
+  [Throws]
+  undefined idleDispatch(IdleRequestCallback callback,
+                         optional IdleRequestOptions options = {});
+
+  /**
+   * Synchronously loads and evaluates the js file located at
+   * 'aResourceURI' with a new, fully privileged global object.
+   *
+   * If `aTargetObj` is specified all properties exported by the module are
+   * copied to that object. This is deprecated and should not be used in
+   * new code.
+   *
+   * @param aResourceURI A resource:// URI string to load the module from.
+   * @param aTargetObj the object to install the exported properties on or null.
+   * @returns the module code's global object.
+   *
+   * The implementation maintains a hash of aResourceURI->global obj.
+   * Subsequent invocations of import with 'aResourceURI' pointing to
+   * the same file will not cause the module to be re-evaluated, but
+   * the symbols in EXPORTED_SYMBOLS will be exported into the
+   * specified target object and the global object returned as above.
+   */
+  [Throws]
+  object import(UTF8String aResourceURI, optional object aTargetObj);
+
+  /**
+   * Synchronously loads and evaluates the JS module source located at
+   * 'aResourceURI'.
+   *
+   * @param aResourceURI A resource:// URI string to load the module from.
+   * @returns the module's namespace object.
+   *
+   * The implementation maintains a hash of aResourceURI->global obj.
+   * Subsequent invocations of import with 'aResourceURI' pointing to
+   * the same file will not cause the module to be re-evaluated.
+   */
+  [Throws]
+  object importESModule(DOMString aResourceURI, optional ImportESModuleOptionsDictionary options = {});
+
+  /**
+   * Defines a property on the given target which lazily imports a JavaScript
+   * module when accessed.
+   *
+   * The first time the property is accessed, the module at the given URL is
+   * imported, and the property is replaced with the module's exported symbol
+   * of the same name.
+   *
+   * Some points to note when using this utility:
+   *
+   * - The cached module export is always stored on the `this` object that was
+   *   used to access the getter. This means that if you define the lazy
+   *   getter on a prototype, the module will be re-imported every time the
+   *   property is accessed on a new instance.
+   *
+   * - The getter property may be overwritten by simple assignment, but as
+   *   with imports, the new property value is always defined on the `this`
+   *   object that the setter is called with.
+   *
+   * - If the module import fails, the getter will throw an error, and the
+   *   property will not be replaced. Each subsequent attempt to access the
+   *   getter will attempt to re-import the object, which will likely continue
+   *   to result in errors.
+   *
+   * @param target The target object on which to define the property.
+   * @param id The name of the property to define, and of the symbol to
+   *           import.
+   * @param resourceURI The resource URI of the module, as passed to
+   *                    ChromeUtils.import.
+   */
+  [Throws]
+  undefined defineModuleGetter(object target, DOMString id, DOMString resourceURI);
+
+  /**
+   * Defines propertys on the given target which lazily imports a ES module
+   * when accessed.
+   *
+   * @param target The target object on which to define the property.
+   * @param modules An object with a property for each module property to be
+   *                imported, where the property name is the name of the
+   *                imported symbol and the value is the module URI.
+   */
+  [Throws]
+  undefined defineESModuleGetters(object target, object modules);
+
+  /**
+   * Returns the scripted location of the first ancestor stack frame with a
+   * principal which is subsumed by the given principal. If no such frame
+   * exists on the call stack, returns null.
+   */
+  object? getCallerLocation(Principal principal);
+
+  /**
+   * Creates a JS Error object with the given message and stack.
+   *
+   * If a stack object is provided, the error object is created in the global
+   * that it belongs to.
+   */
+  [Throws]
+  object createError(DOMString message, optional object? stack = null);
+
+  /**
+   * Request performance metrics to the current process & all content processes.
+   */
+  [NewObject]
+  Promise<sequence<PerformanceInfoDictionary>> requestPerformanceMetrics();
+
+  /**
+   * Set the collection of specific detailed performance timing information.
+   * Selecting 0 for the mask will end existing collection. All metrics that
+   * are chosen will be cleared after updating the mask.
+   *
+   * @param aCollectionMask A bitmask where each bit corresponds to a metric
+   *        to be collected as listed in PerfStats::Metric.
+   */
+  undefined setPerfStatsCollectionMask(unsigned long long aCollectionMask);
+
+  /**
+   * Collect results of detailed performance timing information.
+   * The output is a JSON string containing performance timings.
+   */
+  [NewObject]
+  Promise<DOMString> collectPerfStats();
+
+  /**
+  * Returns a Promise containing a sequence of I/O activities
+  */
+  [NewObject]
+  Promise<sequence<IOActivityDataDictionary>> requestIOActivity();
+
+  /**
+  * Returns a Promise containing all processes info
+  */
+  [NewObject]
+  Promise<ParentProcInfoDictionary> requestProcInfo();
+
+  /**
+   * For testing purpose.
+   */
+  [ChromeOnly]
+  boolean vsyncEnabled();
+
+  [ChromeOnly, Throws]
+  boolean hasReportingHeaderForOrigin(DOMString aOrigin);
+
+  [ChromeOnly]
+  PopupBlockerState getPopupControlState();
+
+  /**
+   * Milliseconds from the last iframe loading an external protocol.
+   */
+  [ChromeOnly]
+  double lastExternalProtocolIframeAllowed();
+
+  /**
+   * For testing purpose we need to reset this value.
+   */
+  [ChromeOnly]
+  undefined resetLastExternalProtocolIframeAllowed();
+
+  /**
+   * Register a new toplevel window global actor. This method may only be
+   * called in the parent process. |name| must be globally unique.
+   *
+   * See JSWindowActor.webidl for WindowActorOptions fields documentation.
+   */
+  [ChromeOnly, Throws]
+  undefined registerWindowActor(UTF8String aName, optional WindowActorOptions aOptions = {});
+
+  [ChromeOnly]
+  undefined unregisterWindowActor(UTF8String aName);
+
+  /**
+   * Register a new toplevel content global actor. This method may only be
+   * called in the parent process. |name| must be globally unique.
+   *
+   * See JSProcessActor.webidl for ProcessActorOptions fields documentation.
+   */
+  [ChromeOnly, Throws]
+  undefined registerProcessActor(UTF8String aName, optional ProcessActorOptions aOptions = {});
+
+  [ChromeOnly]
+  undefined unregisterProcessActor(UTF8String aName);
+
+  [ChromeOnly]
+  // aError should a nsresult.
+  boolean isClassifierBlockingErrorCode(unsigned long aError);
+
+  /**
+   * If leak detection is enabled, print a note to the leak log that this
+   * process will intentionally crash. This should be called only on child
+   * processes for testing purpose.
+   */
+  [ChromeOnly, Throws]
+  undefined privateNoteIntentionalCrash();
+
+  /**
+   * nsIDOMProcessChild for the current process.
+   */
+  [ChromeOnly]
+  readonly attribute nsIDOMProcessChild? domProcessChild;
+
+  /**
+   * nsIDOMProcessParent for all processes.
+   *
+   * The first is for the parent process and all the next are for the content
+   * processes.
+   */
+  [Throws, ChromeOnly]
+  sequence<nsIDOMProcessParent> getAllDOMProcesses();
+
+  /**
+   * Returns a record of user interaction data. Currently only typing,
+   * but will include scrolling and potentially other metrics.
+   *
+   * Valid keys: "Typing"
+   */
+  [Throws, ChromeOnly]
+  record<DOMString, InteractionData> consumeInteractionData();
+
+  /**
+   * Returns a record of user scrolling interactions collected from content processes.
+   *
+   * Valid keys: "Scrolling"
+   */
+  [NewObject]
+  Promise<InteractionData> collectScrollingData();
+
+  [Throws]
+  sequence<FormAutofillConfidences> getFormAutofillConfidences(sequence<Element> elements);
+
+  /**
+   * Returns whether the background of the element is dark.
+   */
+  boolean isDarkBackground(Element element);
+};
+
+/*
+ * This type is a WebIDL representation of mozilla::ProcType.
+ * These must match the similar ones in E10SUtils.sys.mjs, RemoteTypes.h,
+ * ProcInfo.h and ChromeUtils.cpp
+ */
+enum WebIDLProcType {
+ "web",
+ "webIsolated",
+ "file",
+ "extension",
+ "privilegedabout",
+ "privilegedmozilla",
+ "withCoopCoep",
+ "webServiceWorker",
+ "browser",
+ "ipdlUnitTest",
+ "gmpPlugin",
+ "gpu",
+ "vr",
+ "rdd",
+ "socket",
+ "remoteSandboxBroker",
+#ifdef MOZ_ENABLE_FORKSERVER
+ "forkServer",
+#endif
+ "utility",
+ "preallocated",
+ "unknown",
+};
+
+/**
+ * These dictionaries hold information about Firefox running processes and
+ * threads.
+ *
+ * See widget/ProcInfo.h for fields documentation.
+ */
+dictionary ThreadInfoDictionary {
+  long long tid = 0;
+  DOMString name = "";
+  unsigned long long cpuCycleCount = 0;
+  unsigned long long cpuTime = 0;
+};
+
+dictionary WindowInfoDictionary {
+  // Window ID, as known to the parent process.
+  unsigned long long outerWindowId = 0;
+
+  // URI of the document loaded in the window.
+  URI? documentURI = null;
+
+  // Title of the document loaded in the window.
+  // Commonly empty for subframes.
+  DOMString documentTitle = "";
+
+  // `true` if this window is the root for the process.
+  boolean isProcessRoot = false;
+
+  // `true` if this is loaded in the same process as the parent, `false` otherwise.
+  boolean isInProcess = false;
+};
+
+/*
+ * Add new entry to WebIDLUtilityActorName here and update accordingly
+ * UtilityActorNameToWebIDL in dom/base/ChromeUtils.cpp as well as
+ * UtilityActorName in toolkit/components/processtools/ProcInfo.h
+ */
+enum WebIDLUtilityActorName {
+  "unknown",
+  "audioDecoder_Generic",
+  "audioDecoder_AppleMedia",
+  "audioDecoder_WMF",
+  "mfMediaEngineCDM",
+  "jSOracle",
+};
+
+dictionary UtilityActorsDictionary {
+  WebIDLUtilityActorName actorName = "unknown";
+};
+
+/**
+ * Information on a child process.
+ *
+ * # Limitation
+ *
+ * If we lose a race with a process or thread attempting to close the
+ * target process, not all information is available.
+ *
+ * Missing information will generally have its default value.
+ */
+dictionary ChildProcInfoDictionary {
+  // --- System info
+
+  // The cross-process descriptor for this process.
+  long long pid = 0;
+
+  // The best end-user measure for "memory used" that we can obtain without
+  // triggering expensive computations. The value is in bytes.
+  // On Mac and Linux this matches the values shown by the system monitors.
+  // On Windows this will return the Commit Size.
+  unsigned long long memory = 0;
+
+  // Total CPU time spent by the process, in ns.
+  unsigned long long cpuTime = 0;
+
+  // Total CPU cycles used by this process.
+  // On Windows where the resolution of CPU timings is 16ms, this can
+  // be used to determine if a process is idle or slightly active.
+  unsigned long long cpuCycleCount = 0;
+
+  // Thread information for this process.
+  sequence<ThreadInfoDictionary> threads = [];
+
+  // --- Firefox info
+
+  // Internal-to-Firefox process identifier.
+  unsigned long long childID = 0;
+
+  // The origin of the process, e.g. the subset of domain names
+  // that this subset serves.
+  UTF8String origin = "";
+
+  // Type of this child process.
+  WebIDLProcType type = "web";
+
+  // The windows implemented by this process.
+  sequence<WindowInfoDictionary> windows = [];
+
+  // The utility process list of actors if any
+  sequence<UtilityActorsDictionary> utilityActors = [];
+};
+
+/**
+ * Information on the parent process.
+ */
+dictionary ParentProcInfoDictionary {
+  // --- System info
+
+  // The cross-process descriptor for this process.
+  long long pid = 0;
+
+  // The best end-user measure for "memory used" that we can obtain without
+  // triggering expensive computations. The value is in bytes.
+  // On Mac and Linux this matches the values shown by the system monitors.
+  // On Windows this will return the Commit Size.
+  unsigned long long memory = 0;
+
+  // Total CPU time spent by the process, in ns.
+  unsigned long long cpuTime = 0;
+
+  // Total CPU cycles used by this process.
+  // On Windows where the resolution of CPU timings is 16ms, this can
+  // be used to determine if a process is idle or slightly active.
+  unsigned long long cpuCycleCount = 0;
+
+  // Thread information for this process.
+  sequence<ThreadInfoDictionary> threads = [];
+
+  // Information on children processes.
+  sequence<ChildProcInfoDictionary> children = [];
+
+  // --- Firefox info
+  // Type of this parent process.
+  // As of this writing, this is always `browser`.
+  WebIDLProcType type = "browser";
+};
+
+/**
+ * Dictionaries duplicating IPDL types in dom/ipc/DOMTypes.ipdlh
+ * Used by requestPerformanceMetrics
+ */
+dictionary MediaMemoryInfoDictionary {
+  unsigned long long audioSize = 0;
+  unsigned long long videoSize = 0;
+  unsigned long long resourcesSize = 0;
+};
+
+dictionary MemoryInfoDictionary {
+  unsigned long long domDom = 0;
+  unsigned long long domStyle = 0;
+  unsigned long long domOther = 0;
+  unsigned long long jsMemUsage = 0;
+  required MediaMemoryInfoDictionary media;
+};
+
+dictionary CategoryDispatchDictionary
+{
+  unsigned short category = 0;
+  unsigned short count = 0;
+};
+
+dictionary PerformanceInfoDictionary {
+  ByteString host = "";
+  unsigned long pid = 0;
+  unsigned long long windowId = 0;
+  unsigned long long duration = 0;
+  unsigned long long counterId = 0;
+  boolean isWorker = false;
+  boolean isTopLevel = false;
+  required MemoryInfoDictionary memoryInfo;
+  sequence<CategoryDispatchDictionary> items = [];
+};
+
+/**
+ * Used by requestIOActivity() to return the number of bytes
+ * that were read (rx) and/or written (tx) for a given location.
+ *
+ * Locations can be sockets or files.
+ */
+dictionary IOActivityDataDictionary {
+  ByteString location = "";
+  unsigned long long rx = 0;
+  unsigned long long tx = 0;
+};
+
+/**
+ * Used by principals and the script security manager to represent origin
+ * attributes. The first dictionary is designed to contain the full set of
+ * OriginAttributes, the second is used for pattern-matching (i.e. does this
+ * OriginAttributesDictionary match the non-empty attributes in this pattern).
+ *
+ * IMPORTANT: If you add any members here, you need to do the following:
+ * (1) Add them to both dictionaries.
+ * (2) Update the methods on mozilla::OriginAttributes, including equality,
+ *     serialization, deserialization, and inheritance.
+ * (3) Update the methods on mozilla::OriginAttributesPattern, including matching.
+ */
+[GenerateInitFromJSON]
+dictionary OriginAttributesDictionary {
+  unsigned long userContextId = 0;
+  boolean inIsolatedMozBrowser = false;
+  unsigned long privateBrowsingId = 0;
+  DOMString firstPartyDomain = "";
+  DOMString geckoViewSessionContextId = "";
+  DOMString partitionKey = "";
+};
+
+[GenerateInitFromJSON, GenerateToJSON]
+dictionary OriginAttributesPatternDictionary {
+  unsigned long userContextId;
+  boolean inIsolatedMozBrowser;
+  unsigned long privateBrowsingId;
+  DOMString firstPartyDomain;
+  DOMString geckoViewSessionContextId;
+  // partitionKey takes precedence over partitionKeyPattern.
+  DOMString partitionKey;
+  PartitionKeyPatternDictionary partitionKeyPattern;
+};
+
+dictionary PartitionKeyPatternDictionary {
+  DOMString scheme;
+  DOMString baseDomain;
+  long port;
+};
+
+dictionary CompileScriptOptionsDictionary {
+  /**
+   * The character set from which to decode the script.
+   */
+  DOMString charset = "utf-8";
+
+  /**
+   * If true, certain parts of the script may be parsed lazily, the first time
+   * they are used, rather than eagerly parsed at load time.
+   */
+  boolean lazilyParse = false;
+
+  /**
+   * If true, the script will be compiled so that its last expression will be
+   * returned as the value of its execution. This makes certain types of
+   * optimization impossible, and disables the JIT in many circumstances, so
+   * should not be used when not absolutely necessary.
+   */
+  boolean hasReturnValue = false;
+};
+
+dictionary ImportESModuleOptionsDictionary {
+  /**
+   * If true, a distinct module loader will be used, in the system principal,
+   * but with a distinct global so that the DevTools can load a distinct set
+   * of modules and do not interfere with its debuggee.
+   */
+  boolean loadInDevToolsLoader;
+};
+
+/**
+ * A JS object whose properties specify what portion of the heap graph to
+ * write. The recognized properties are:
+ *
+ * * globals: [ global, ... ]
+ *   Dump only nodes that either:
+ *   - belong in the compartment of one of the given globals;
+ *   - belong to no compartment, but do belong to a Zone that contains one of
+ *     the given globals;
+ *   - are referred to directly by one of the last two kinds of nodes; or
+ *   - is the fictional root node, described below.
+ *
+ * * debugger: Debugger object
+ *   Like "globals", but use the Debugger's debuggees as the globals.
+ *
+ * * runtime: true
+ *   Dump the entire heap graph, starting with the JSRuntime's roots.
+ *
+ * One, and only one, of these properties must exist on the boundaries object.
+ *
+ * The root of the dumped graph is a fictional node whose ubi::Node type name is
+ * "CoreDumpRoot". If we are dumping the entire ubi::Node graph, this root node
+ * has an edge for each of the JSRuntime's roots. If we are dumping a selected
+ * set of globals, the root has an edge to each global, and an edge for each
+ * incoming JS reference to the selected Zones.
+ */
+dictionary HeapSnapshotBoundaries {
+  sequence<object> globals;
+  object           debugger;
+  boolean          runtime;
+};
+
+dictionary Base64URLEncodeOptions {
+  /** Specifies whether the output should be padded with "=" characters. */
+  required boolean pad;
+};
+
+enum Base64URLDecodePadding {
+  /**
+   * Fails decoding if the input is unpadded. RFC 4648, section 3.2 requires
+   * padding, unless the referring specification prohibits it.
+   */
+  "require",
+
+  /** Tolerates padded and unpadded input. */
+  "ignore",
+
+  /**
+   * Fails decoding if the input is padded. This follows the strict base64url
+   * variant used in JWS (RFC 7515, Appendix C) and HTTP Encrypted
+   * Content-Encoding (draft-ietf-httpbis-encryption-encoding-01).
+   */
+  "reject"
+};
+
+dictionary Base64URLDecodeOptions {
+  /** Specifies the padding mode for decoding the input. */
+  required Base64URLDecodePadding padding;
+};
+
+// Keep this in sync with PopupBlocker::PopupControlState!
+enum PopupBlockerState {
+  "openAllowed",
+  "openControlled",
+  "openBlocked",
+  "openAbused",
+  "openOverridden",
+};
diff --git a/dom/chrome-webidl/ClonedErrorHolder.webidl b/dom/chrome-webidl/ClonedErrorHolder.webidl
new file mode 100644
index 0000000000..8ab62f99ed
--- /dev/null
+++ b/dom/chrome-webidl/ClonedErrorHolder.webidl
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * A stub object to hold an Error, Exception, or DOMException object to be
+ * transferred via structured clone. The object will automatically be decoded
+ * directly into the type of the error object that it wraps.
+ *
+ * This is a temporary workaround for lack of native Error and Exception
+ * cloning support, and can be removed once bug 1556604 and bug 1561357 are
+ * fixed.
+ */
+[ChromeOnly, Exposed=Window]
+interface ClonedErrorHolder {
+  [Throws]
+  constructor(object aError);
+};
diff --git a/dom/chrome-webidl/DOMCollectedFrames.webidl b/dom/chrome-webidl/DOMCollectedFrames.webidl
new file mode 100644
index 0000000000..4875fbf8ba
--- /dev/null
+++ b/dom/chrome-webidl/DOMCollectedFrames.webidl
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * A single frame collected by the |CompositionRecorder|.
+ */
+[GenerateConversionToJS]
+dictionary DOMCollectedFrame {
+    /**
+     * The offset of the frame past the start point of the recording (in
+     * milliseconds).
+     */
+    required double timeOffset;
+    /** A data: URI containing the PNG image data of the frame. */
+    required ByteString dataUri;
+};
+
+/**
+ * Information about frames collected by the |CompositionRecorder|.
+ */
+[GenerateConversionToJS]
+dictionary DOMCollectedFrames {
+    /** The collected frames. */
+    required sequence<DOMCollectedFrame> frames;
+    /** The start point of the recording (in milliseconds). */
+    required double recordingStart;
+};
diff --git a/dom/chrome-webidl/DebuggerNotification.webidl b/dom/chrome-webidl/DebuggerNotification.webidl
new file mode 100644
index 0000000000..d549eb7ae9
--- /dev/null
+++ b/dom/chrome-webidl/DebuggerNotification.webidl
@@ -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/. */
+
+enum DebuggerNotificationType {
+  // DebuggerNotification
+  "setTimeout",
+  "clearTimeout",
+  "setInterval",
+  "clearInterval",
+  "requestAnimationFrame",
+  "cancelAnimationFrame",
+
+  // CallbackDebuggerNotification
+  "setTimeoutCallback",
+  "setIntervalCallback",
+  "requestAnimationFrameCallback",
+
+  // EventCallbackDebuggerNotification
+  "domEvent",
+};
+
+[ChromeOnly, Exposed=Window]
+interface DebuggerNotification {
+  readonly attribute DebuggerNotificationType type;
+
+  // The global object that has triggered the notification.
+  readonly attribute object global;
+};
+
+// For DOM events, we send notifications just before, and just after the
+// event handler has been dispatched so that listeners
+enum CallbackDebuggerNotificationPhase {
+  "pre",
+  "post",
+};
+
+// A base notification type for notifications that are dispatched as pairs with
+// a before and after notification.
+[ChromeOnly, Exposed=Window]
+interface CallbackDebuggerNotification : DebuggerNotification {
+  readonly attribute CallbackDebuggerNotificationPhase phase;
+};
+
+enum EventCallbackDebuggerNotificationType {
+  "global",
+  "node",
+  "xhr",
+  "worker",
+  "websocket",
+};
+
+// A notification that about the engine calling a DOM event handler.
+[ChromeOnly, Exposed=Window]
+interface EventCallbackDebuggerNotification : CallbackDebuggerNotification {
+  readonly attribute Event event;
+  readonly attribute EventCallbackDebuggerNotificationType targetType;
+};
diff --git a/dom/chrome-webidl/DebuggerNotificationObserver.webidl b/dom/chrome-webidl/DebuggerNotificationObserver.webidl
new file mode 100644
index 0000000000..e37d2dc312
--- /dev/null
+++ b/dom/chrome-webidl/DebuggerNotificationObserver.webidl
@@ -0,0 +1,31 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+callback DebuggerNotificationCallback = undefined (DebuggerNotification n);
+
+[ChromeOnly, Exposed=(Window, Worker)]
+interface DebuggerNotificationObserver {
+  [Throws]
+  constructor();
+
+  // Throws if the object is not a browser global or does not support
+  // debugger notifications.
+  // Returns false if already connected to this global.
+  [Throws]
+  boolean connect(object global);
+
+  // Throws if the object is not a browser global or does not support
+  // debugger notifications.
+  // Returns false if not connected to this global.
+  [Throws]
+  boolean disconnect(object global);
+
+  // Returns false if listener already added.
+  boolean addListener(DebuggerNotificationCallback handler);
+
+  // Returns false if listener was not found.
+  boolean removeListener(DebuggerNotificationCallback handler);
+};
diff --git a/dom/chrome-webidl/DebuggerUtils.webidl b/dom/chrome-webidl/DebuggerUtils.webidl
new file mode 100644
index 0000000000..31421efcaa
--- /dev/null
+++ b/dom/chrome-webidl/DebuggerUtils.webidl
@@ -0,0 +1,16 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+// Interfaces and structures for use by the debugger and other devtools.
+
+// Data sent to the devtools when new data has been received in an HTML parse.
+[GenerateToJSON]
+dictionary HTMLContent {
+  DOMString parserID;
+  DOMString uri;
+  DOMString contents;
+  boolean complete;
+};
diff --git a/dom/chrome-webidl/DocumentL10n.webidl b/dom/chrome-webidl/DocumentL10n.webidl
new file mode 100644
index 0000000000..5f252de2cb
--- /dev/null
+++ b/dom/chrome-webidl/DocumentL10n.webidl
@@ -0,0 +1,47 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * DocumentL10n is a public interface for handling DOM localization.
+ *
+ * In it's current form it exposes the DOMLocalization API which
+ * allows for localization-specific DOM operations on a defined
+ * localization context, and retrival of formatted localization
+ * messages out of that context.
+ *
+ * The context is created when `<link rel="localization"/>` elements
+ * are added to the document, and is removed in case all links
+ * of that type are removed from it.
+ */
+[LegacyNoInterfaceObject,
+ Exposed=Window]
+interface DocumentL10n : DOMLocalization {
+  /**
+   * A promise which gets resolved when the initial DOM localization resources
+   * fetching is complete and the initial translation of the DOM is finished.
+   */
+  readonly attribute Promise<any> ready;
+
+  /**
+   * An overload for the DOMLocalization::connectRoot which takes an optional second
+   * argument to allow the user to express an intent of translating the root
+   * as soon as the localization becomes available.
+   *
+   * If the root is being connected while the document is still being parsed,
+   * then irrelevant of the value of the second argument, it will be translated
+   * as part of the initial translation step right after the parsing completes.
+   *
+   * If the root is being connected after the document is parsed, then the
+   * second argument controls whether the root is also going to get translated,
+   * or just connected.
+   *
+   * This is a temporary workaround to avoid having to wait for the `DocumentL10n`
+   * to become active. It should be unnecessary once we remove JSM and make
+   * the `TranslateFragment` be available immediately when `DocumentL10n` becomes
+   * available.
+   */
+  [Throws] undefined connectRoot(Node aElement, optional boolean aTranslate = false);
+};
diff --git a/dom/chrome-webidl/DominatorTree.webidl b/dom/chrome-webidl/DominatorTree.webidl
new file mode 100644
index 0000000000..518f0e9802
--- /dev/null
+++ b/dom/chrome-webidl/DominatorTree.webidl
@@ -0,0 +1,70 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+typedef unsigned long long NodeId;
+typedef unsigned long long NodeSize;
+
+/**
+ * In a directed graph with a root node `R`, a node `A` is said to "dominate" a
+ * node `B` iff every path from `R` to `B` contains `A`. A node `A` is said to
+ * be the "immediate dominator" of a node `B` iff it dominates `B`, is not `B`
+ * itself, and does not dominate any other nodes which also dominate `B` in
+ * turn.
+ *
+ * If we take every node from a graph `G` and create a new graph `T` with edges
+ * to each node from its immediate dominator, then `T` is a tree (each node has
+ * only one immediate dominator, or none if it is the root). This tree is called
+ * a "dominator tree".
+ *
+ * This interface represents a dominator tree constructed from a HeapSnapshot's
+ * heap graph. The domination relationship and dominator trees are useful tools
+ * for analyzing heap graphs because they tell you:
+ *
+ *   - Exactly what could be reclaimed by the GC if some node `A` became
+ *     unreachable: those nodes which are dominated by `A`,
+ *
+ *   - The "retained size" of a node in the heap graph, in contrast to its
+ *     "shallow size". The "shallow size" is the space taken by a node itself,
+ *     not counting anything it references. The "retained size" of a node is its
+ *     shallow size plus the size of all the things that would be collected if
+ *     the original node wasn't (directly or indirectly) referencing them. In
+ *     other words, the retained size is the shallow size of a node plus the
+ *     shallow sizes of every other node it dominates. For example, the root
+ *     node in a binary tree might have a small shallow size that does not take
+ *     up much space itself, but it dominates the rest of the binary tree and
+ *     its retained size is therefore significant (assuming no external
+ *     references into the tree).
+ */
+[ChromeOnly, Exposed=(Window,Worker)]
+interface DominatorTree {
+  /**
+   * The `NodeId` for the root of the dominator tree. This is a "meta-root" in
+   * that it has an edge to each GC root in the heap snapshot this dominator
+   * tree was created from.
+   */
+  readonly attribute NodeId root;
+
+  /**
+   * Get the retained size of the node with the given id. If given an invalid
+   * id, null is returned. Throws an error on OOM.
+   */
+  [Throws]
+  NodeSize? getRetainedSize(NodeId node);
+
+  /**
+   * Get the set of ids of nodes immediately dominated by the node with the
+   * given id. The resulting array is sorted by greatest to least retained
+   * size. If given an invalid id, null is returned. Throws an error on OOM.
+   */
+  [Throws]
+  sequence<NodeId>? getImmediatelyDominated(NodeId node);
+
+  /**
+   * Get the immediate dominator of the node with the given id. Returns null if
+   * given an invalid id, or the id of the root node.
+   */
+  NodeId? getImmediateDominator(NodeId node);
+};
diff --git a/dom/chrome-webidl/Flex.webidl b/dom/chrome-webidl/Flex.webidl
new file mode 100644
index 0000000000..f04897e65c
--- /dev/null
+++ b/dom/chrome-webidl/Flex.webidl
@@ -0,0 +1,94 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * These objects support visualization of flex containers by the
+ * dev tools.
+ */
+
+/**
+ * A flex container's main and cross axes are either horizontal or
+ * vertical, each with two possible directions.
+ */
+enum FlexPhysicalDirection {
+  "horizontal-lr",
+  "horizontal-rl",
+  "vertical-tb",
+  "vertical-bt",
+};
+
+[ChromeOnly, Exposed=Window]
+interface Flex
+{
+  sequence<FlexLineValues> getLines();
+
+  /**
+   * The physical direction in which successive flex items are placed,
+   * within a flex line in this flex container.
+   */
+  readonly attribute FlexPhysicalDirection mainAxisDirection;
+
+  /**
+   * The physical direction in which successive flex lines are placed
+   * in this flex container (if it is or were multi-line).
+   */
+  readonly attribute FlexPhysicalDirection crossAxisDirection;
+};
+
+/**
+ * This indicates which flex factor (flex-grow vs. flex-shrink) the
+ * flex layout algorithm uses internally when resolving flexible sizes
+ * in a given flex line, per flexbox spec section 9.7 step 1. Note that
+ * this value doesn't necessarily mean that any items on this line
+ * are *actually* growing (or shrinking).  This simply indicates what
+ * the layout algorithm "wants" to do, based on the free space --
+ * and items will stretch from their flex base size in the corresponding
+ * direction, if permitted by their min/max constraints and their
+ * corresponding flex factor.
+ */
+enum FlexLineGrowthState { "shrinking", "growing" };
+
+[ChromeOnly, Exposed=Window]
+interface FlexLineValues
+{
+  readonly attribute FlexLineGrowthState growthState;
+  readonly attribute double crossStart;
+  readonly attribute double crossSize;
+
+  // firstBaselineOffset measures from flex-start edge.
+  readonly attribute double firstBaselineOffset;
+
+  // lastBaselineOffset measures from flex-end edge.
+  readonly attribute double lastBaselineOffset;
+
+  /**
+   * getItems() returns FlexItemValues only for the Elements in
+   * this Flex container -- ignoring struts and abs-pos Elements.
+   */
+  sequence<FlexItemValues> getItems();
+};
+
+/**
+ * Item main sizes have either been unclamped, clamped to the minimum,
+ * or clamped to the maximum.
+ */
+enum FlexItemClampState {
+  "unclamped", "clamped_to_min", "clamped_to_max"
+};
+
+[ChromeOnly, Exposed=Window]
+interface FlexItemValues
+{
+  readonly attribute Node? node;
+  readonly attribute DOMRectReadOnly frameRect;
+  readonly attribute double mainBaseSize;
+  readonly attribute double mainDeltaSize;
+  readonly attribute double mainMinSize;
+  readonly attribute double mainMaxSize;
+  readonly attribute double crossMinSize;
+  readonly attribute double crossMaxSize;
+  readonly attribute FlexItemClampState clampState;
+};
diff --git a/dom/chrome-webidl/Fluent.webidl b/dom/chrome-webidl/Fluent.webidl
new file mode 100644
index 0000000000..5a8d6fca2b
--- /dev/null
+++ b/dom/chrome-webidl/Fluent.webidl
@@ -0,0 +1,51 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+[ChromeOnly, Exposed=Window]
+interface FluentResource {
+  constructor(UTF8String source);
+};
+
+[ChromeOnly, Exposed=Window]
+interface FluentPattern {};
+
+/**
+ * FluentMessage is a structure storing an unresolved L10nMessage,
+ * as returned by the Fluent Bundle.
+ *
+ * It stores a FluentPattern of the value and attributes, which
+ * can be then passed to bundle.formatPattern.
+ */
+
+dictionary FluentMessage {
+  FluentPattern? value = null;
+  required record<UTF8String, FluentPattern> attributes;
+};
+
+typedef record<UTF8String, (UTF8String or double)?> L10nArgs;
+
+dictionary FluentBundleOptions {
+  boolean useIsolating = false;
+  UTF8String pseudoStrategy;
+};
+
+dictionary FluentBundleAddResourceOptions {
+  boolean allowOverrides = false;
+};
+
+[ChromeOnly, Exposed=Window]
+interface FluentBundle {
+  [Throws]
+  constructor((UTF8String or sequence<UTF8String>) aLocales, optional FluentBundleOptions aOptions = {});
+
+  [Pure, Cached]
+  readonly attribute sequence<UTF8String> locales;
+
+  undefined addResource(FluentResource aResource, optional FluentBundleAddResourceOptions aOptions = {});
+  boolean hasMessage(UTF8String id);
+  FluentMessage? getMessage(UTF8String id);
+  [Throws]
+  UTF8String formatPattern(FluentPattern pattern, optional L10nArgs? aArgs = null, optional object aErrors);
+};
diff --git a/dom/chrome-webidl/FrameLoader.webidl b/dom/chrome-webidl/FrameLoader.webidl
new file mode 100644
index 0000000000..5669d2af41
--- /dev/null
+++ b/dom/chrome-webidl/FrameLoader.webidl
@@ -0,0 +1,233 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface LoadContext;
+interface RemoteTab;
+interface URI;
+interface nsIDocShell;
+interface nsIPrintSettings;
+interface nsIWebBrowserPersistDocumentReceiver;
+interface nsIWebProgressListener;
+
+[ChromeOnly,
+ Exposed=Window]
+interface FrameLoader {
+  /**
+   * Get the docshell from the frame loader.
+   */
+  [GetterThrows]
+  readonly attribute nsIDocShell? docShell;
+
+  /**
+   * Get this frame loader's RemoteTab, if it has a remote frame.  Otherwise,
+   * returns null.
+   */
+  readonly attribute RemoteTab? remoteTab;
+
+  /**
+   * Get an nsILoadContext for the top-level docshell. For remote
+   * frames, a shim is returned that contains private browsing and app
+   * information.
+   */
+  readonly attribute LoadContext loadContext;
+
+  /**
+   * Get the root BrowsingContext within the frame.
+   * This may be null immediately after creating a remote frame.
+   */
+  readonly attribute BrowsingContext? browsingContext;
+
+  /**
+   * Find out whether the loader's frame is at too great a depth in
+   * the frame tree.  This can be used to decide what operations may
+   * or may not be allowed on the loader's docshell.
+   */
+  [Pure]
+  readonly attribute boolean depthTooGreat;
+
+  /**
+   * Find out whether the loader's frame is a remote frame.
+   */
+  readonly attribute boolean isRemoteFrame;
+
+  // Note, when frameloaders are swapped, also messageManagers are swapped.
+  readonly attribute MessageSender? messageManager;
+
+  /**
+   * Force a remote browser to recompute its dimension and screen position.
+   */
+  [Throws]
+  undefined requestUpdatePosition();
+
+  /**
+   * Force a TabStateFlush from native sessionStoreListeners.
+   * Returns a promise that resolves when all session store data has been
+   * flushed.
+   */
+  [NewObject]
+  Promise<undefined> requestTabStateFlush();
+
+  /**
+   * Force Epoch update in native sessionStoreListeners.
+   */
+  undefined requestEpochUpdate(unsigned long aEpoch);
+
+  /**
+   * Request a session history update in native sessionStoreListeners.
+   */
+  undefined requestSHistoryUpdate();
+
+  /**
+   * Creates a print preview document in this frame, or updates the existing
+   * print preview document with new print settings.
+   *
+   * @param aPrintSettings The print settings to use to layout the print
+   *   preview document.
+   * @param aSourceBrowsingContext Optionally, the browsing context that
+   *   contains the document from which the print preview is to be generated,
+   *   which must be in the same process as the browsing context of the frame
+   *   loader itself.
+   *
+   *   This should only be passed on the first call.  It should not be passed
+   *   for any subsequent calls that are made to update the existing print
+   *   preview document with a new print settings object.
+   * @return A Promise that resolves with a PrintPreviewSuccessInfo on success.
+   */
+  [NewObject]
+  Promise<unsigned long> printPreview(nsIPrintSettings aPrintSettings,
+                                      BrowsingContext? aSourceBrowsingContext);
+
+  /**
+   * Inform the print preview document that we're done with it.
+   */
+  undefined exitPrintPreview();
+
+  /**
+   * The element which owns this frame loader.
+   *
+   * For example, if this is a frame loader for an <iframe>, this attribute
+   * returns the iframe element.
+   */
+  [Pure]
+  readonly attribute Element? ownerElement;
+
+
+  /**
+   * Cached childID of the ContentParent owning the RemoteTab in this frame
+   * loader. This can be used to obtain the childID after the RemoteTab died.
+   */
+  [Pure]
+  readonly attribute unsigned long long childID;
+
+  /**
+   * Find out whether the owner content really is a mozbrowser. <xul:browser>
+   * is not considered to be a mozbrowser frame.
+   */
+  [Pure]
+  readonly attribute boolean ownerIsMozBrowserFrame;
+
+  /**
+   * The last known width of the frame. Reading this property will not trigger
+   * a reflow, and therefore may not reflect the current state of things. It
+   * should only be used in asynchronous APIs where values are not guaranteed
+   * to be up-to-date when received.
+   */
+  [Pure]
+  readonly attribute unsigned long lazyWidth;
+
+  /**
+   * The last known height of the frame. Reading this property will not trigger
+   * a reflow, and therefore may not reflect the current state of things. It
+   * should only be used in asynchronous APIs where values are not guaranteed
+   * to be up-to-date when received.
+   */
+  [Pure]
+  readonly attribute unsigned long lazyHeight;
+
+  /**
+   * Is `true` if the frameloader is dead (destroy has been called on it)
+   */
+  [Pure]
+  readonly attribute boolean isDead;
+};
+
+/**
+ * Interface for objects which represent a document that can be
+ * serialized with nsIWebBrowserPersist.  This interface is
+ * asynchronous because the actual document can be in another process
+ * (e.g., if this object is a FrameLoader for an out-of-process
+ * frame).
+ *
+ * @see nsIWebBrowserPersistDocumentReceiver
+ * @see nsIWebBrowserPersistDocument
+ * @see nsIWebBrowserPersist
+ *
+ * @param aContext
+ *        The browsing context of the subframe we'd like to persist.
+ *        If set to nullptr, WebBrowserPersistable will attempt to persist
+ *        the top-level document. If the browsing context is for a subframe
+ *        that is not held beneath the WebBrowserPersistable, aRecv's onError
+ *        method will be called with NS_ERROR_NO_CONTENT.
+ * @param aRecv
+ *        The nsIWebBrowserPersistDocumentReceiver is a callback that
+ *        will be fired once the document is ready for persisting.
+ */
+interface mixin WebBrowserPersistable
+{
+  [Throws]
+  undefined startPersistence(BrowsingContext? aContext,
+                             nsIWebBrowserPersistDocumentReceiver aRecv);
+};
+
+enum PrintPreviewOrientation {
+    "landscape",
+    "portrait",
+    "unspecified"
+};
+
+/**
+ * Interface for the object that's used to resolve the Promise returned from
+ * FrameLoader.printPreview() if that method successfully creates the print
+ * preview document/successfully updates it with new settings.
+ */
+[GenerateConversionToJS]
+dictionary PrintPreviewSuccessInfo {
+  /**
+   * The total number of sheets of paper required to print, taking into account
+   * the provided nsIPrintSettings.  This takes into account page range
+   * selection, the pages-per-sheet, whether duplex printing is enabled, etc.
+   */
+  unsigned long sheetCount = 0;
+
+  /**
+   * The total number of virtual pages, not taking into account page range
+   * selection, the pages-per-sheet, whether duplex printing is enabled, etc.
+   */
+  unsigned long totalPageCount = 0;
+
+  /**
+   * Whether the preview is empty because of page range selection.
+   */
+  boolean isEmpty = false;
+
+  /**
+   * Whether the document or any subdocument has a selection that can be
+   * printed.
+   */
+  boolean hasSelection = false;
+
+  /**
+   * Whether the previewed document has a selection itself.
+   */
+  boolean hasSelfSelection = false;
+
+  /**
+   * Specified orientation of the document, or "unspecified".
+   */
+  PrintPreviewOrientation orientation = "unspecified";
+};
+
+FrameLoader includes WebBrowserPersistable;
diff --git a/dom/chrome-webidl/Glean.webidl b/dom/chrome-webidl/Glean.webidl
new file mode 100644
index 0000000000..f8f55e2418
--- /dev/null
+++ b/dom/chrome-webidl/Glean.webidl
@@ -0,0 +1,45 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface nsISupports;
+
+[ChromeOnly, Exposed=Window]
+interface GleanCategory {
+  /**
+   * Get a metric by name.
+   *
+   * Returns an object of the corresponding metric type,
+   * with only the allowed functions available.
+   */
+  getter nsISupports (DOMString identifier);
+};
+
+[ChromeOnly, Exposed=Window]
+interface GleanImpl {
+  /**
+   * Get a metric category by name.
+   *
+   * Returns an object for further metric lookup.
+   */
+  getter GleanCategory (DOMString identifier);
+};
+
+[ChromeOnly, Exposed=Window]
+interface GleanLabeled {
+  /**
+   * Get a specific metric for a given label.
+   *
+   * If a set of acceptable labels were specified in the `metrics.yaml` file,
+   * and the given label is not in the set, it will be recorded under the
+   * special `OTHER_LABEL` label.
+   *
+   * If a set of acceptable labels was not specified in the `metrics.yaml` file,
+   * only the first 16 unique labels will be used.
+   * After that, any additional labels will be recorded under the special
+   * `OTHER_LABEL` label.
+   */
+  getter nsISupports (DOMString identifier);
+};
diff --git a/dom/chrome-webidl/GleanPings.webidl b/dom/chrome-webidl/GleanPings.webidl
new file mode 100644
index 0000000000..3dee22205b
--- /dev/null
+++ b/dom/chrome-webidl/GleanPings.webidl
@@ -0,0 +1,15 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface nsIGleanPing;
+
+[ChromeOnly, Exposed=Window]
+interface GleanPingsImpl {
+  /**
+   * Get a ping by name.
+   */
+  getter nsIGleanPing (DOMString identifier);
+};
diff --git a/dom/chrome-webidl/HeapSnapshot.webidl b/dom/chrome-webidl/HeapSnapshot.webidl
new file mode 100644
index 0000000000..8b1b0b1a14
--- /dev/null
+++ b/dom/chrome-webidl/HeapSnapshot.webidl
@@ -0,0 +1,105 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * A HeapSnapshot represents a snapshot of the heap graph
+ */
+[ChromeOnly, Exposed=(Window,Worker)]
+interface HeapSnapshot {
+  /**
+   * A time stamp of when the heap snapshot was taken, if available. Units are
+   * microseconds since midnight (00:00:00) 1 January 1970 UTC.
+   */
+  readonly attribute unsigned long long? creationTime;
+
+  /**
+   * Take a census of the heap snapshot.
+   *
+   * This is the same as |Debugger.Memory.prototype.takeCensus|, but operates on
+   * the offline heap snapshot's serialized heap graph rather than the live heap
+   * graph. The same optional configuration options that can be passed to that
+   * function can be passed here.
+   *
+   * The returned value is determined by the `"breakdown"` option used, and is
+   * usually a `Map`, `Object`, or `Array`. For example, the following breakdown
+   *
+   *     {
+   *       by: "coarseType",
+   *       objects: { by: "objectClass" },
+   *       other:   { by: "internalType" }
+   *     }
+   *
+   * produces a result like this:
+   *
+   *     {
+   *       "objects": {
+   *         "Function":         { "count": 404, "bytes": 37328 },
+   *         "Object":           { "count": 11,  "bytes": 1264 },
+   *         "Debugger":         { "count": 1,   "bytes": 416 },
+   *         "ScriptSource":     { "count": 1,   "bytes": 64 },
+   *         // ... omitted for brevity...
+   *       },
+   *       "scripts":            { "count": 1,   "bytes": 0 },
+   *       "strings":            { "count": 701, "bytes": 49080 },
+   *       "other": {
+   *         "js::Shape":        { "count": 450, "bytes": 0 },
+   *         "js::BaseShape":    { "count": 21,  "bytes": 0 },
+   *         "js::ObjectGroup":  { "count": 17,  "bytes": 0 }
+   *       }
+   *     }
+   *
+   * See the `takeCensus` section of the `js/src/doc/Debugger/Debugger.Memory.md`
+   * file for detailed documentation.
+   */
+  [Throws]
+  any takeCensus(object? options);
+
+  /**
+   * Describe `node` with the specified `breakdown`. See the comment above
+   * `takeCensus` or `js/src/doc/Debugger/Debugger.Memory.md` for detailed
+   * documentation on breakdowns.
+   *
+   * Throws an error when `node` is not the id of a node in the heap snapshot,
+   * or if the breakdown is invalid.
+   */
+  [Throws]
+  any describeNode(object breakdown, NodeId node);
+
+  /**
+   * Compute the dominator tree for this heap snapshot.
+   *
+   * @see DominatorTree.webidl
+   */
+  [Throws]
+  DominatorTree computeDominatorTree();
+
+  /**
+   * Find the shortest retaining paths from the node associated with the ID
+   * `start` to each node associated with the IDs in `targets`. Find at most
+   * `maxNumPaths` retaining paths for each target node.
+   *
+   * The return value is a Map object mapping from each target node ID to an
+   * array of retaining paths. The array may be empty if we did not find any
+   * retaining paths.
+   *
+   * A path is an array of objects of the form:
+   *
+   *     {
+   *         predecessor: <node ID>,
+   *         edge: <string or null>,
+   *     }
+   *
+   * The first `predecessor` will always be `start`. The last edge in the path
+   * leads to the `target` node that is mapped to the path; the `target` does
+   * not appear as a `predecessor` in the path.
+   *
+   * Throws when `start` or any of the elements of `targets` are not an ID of a
+   * node in the snapshot, or if we encounter an out of memory exception.
+   */
+  [Throws]
+  object computeShortestPaths(NodeId start, sequence<NodeId> targets,
+                              unsigned long long maxNumPaths);
+};
diff --git a/dom/chrome-webidl/IOUtils.webidl b/dom/chrome-webidl/IOUtils.webidl
new file mode 100644
index 0000000000..e1b67a53bd
--- /dev/null
+++ b/dom/chrome-webidl/IOUtils.webidl
@@ -0,0 +1,766 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface nsIFile;
+
+/**
+ * IOUtils is a simple, efficient interface for performing file I/O from a
+ * privileged chrome-only context. All asynchronous I/O tasks are run on
+ * a background thread.
+ *
+ * Pending I/O tasks will block shutdown at the |profileBeforeChange| phase.
+ * During this shutdown phase, no additional I/O tasks will be accepted --
+ * method calls to this interface will reject once shutdown has entered this
+ * phase.
+ *
+ * IOUtils methods may reject for any number of reasons. Reasonable attempts
+ * have been made to map each common operating system error to a |DOMException|.
+ * Most often, a caller only needs to check if a given file wasn't found by
+ * catching the rejected error and checking if |ex.name === 'NotFoundError'|.
+ * In other cases, it is likely sufficient to allow the error to be caught and
+ * reported elsewhere.
+ */
+[ChromeOnly, Exposed=(Window, Worker)]
+namespace IOUtils {
+ /**
+   * Reads up to |opts.maxBytes| of the file at |path| according to |opts|.
+   *
+   * NB: The maximum file size that can be read is UINT32_MAX.
+   *
+   * @param path An absolute file path.
+   *
+   * @return Resolves with an array of unsigned byte values read from disk,
+   *         otherwise rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<Uint8Array> read(DOMString path, optional ReadOptions opts = {});
+  /**
+   * Reads the UTF-8 text file located at |path| and returns the decoded
+   * contents as a |DOMString|.
+   *
+   * NB: The maximum file size that can be read is UINT32_MAX.
+   *
+   * @param path An absolute file path.
+   *
+   * @return Resolves with the file contents encoded as a string, otherwise
+   *         rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<UTF8String> readUTF8(DOMString path, optional ReadUTF8Options opts = {});
+  /**
+   * Read the UTF-8 text file located at |path| and return the contents
+   * parsed as JSON into a JS value.
+   *
+   * NB: The maximum file size that can be read is UINT32_MAX.
+   *
+   * @param path An absolute path.
+   *
+   * @return Resolves with the contents of the file parsed as JSON.
+   */
+  [NewObject]
+  Promise<any> readJSON(DOMString path, optional ReadUTF8Options opts = {});
+  /**
+   * Attempts to safely write |data| to a file at |path|.
+   *
+   * This operation can be made atomic by specifying the |tmpPath| option. If
+   * specified, then this method ensures that the destination file is not
+   * modified until the data is entirely written to the temporary file, after
+   * which point the |tmpPath| is moved to the specified |path|.
+   *
+   * The target file can also be backed up to a |backupFile| before any writes
+   * are performed to prevent data loss in case of corruption.
+   *
+   * @param path    An absolute file path.
+   * @param data    Data to write to the file at path.
+   *
+   * @return Resolves with the number of bytes successfully written to the file,
+   *         otherwise rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<unsigned long long> write(DOMString path, Uint8Array data, optional WriteOptions options = {});
+  /**
+   * Attempts to encode |string| to UTF-8, then safely write the result to a
+   * file at |path|. Works exactly like |write|.
+   *
+   * @param path      An absolute file path.
+   * @param string    A string to write to the file at path.
+   * @param options   Options for writing the file.
+   *
+   * @return Resolves with the number of bytes successfully written to the file,
+   *         otherwise rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<unsigned long long> writeUTF8(DOMString path, UTF8String string, optional WriteOptions options = {});
+  /**
+   * Attempts to serialize |value| into a JSON string and encode it as into a
+   * UTF-8 string, then safely write the result to a file at |path|. Works
+   * exactly like |write|.
+   *
+   * @param path      An absolute file path
+   * @param value     The value to be serialized.
+   * @param options   Options for writing the file. The "append" mode is not supported.
+   *
+   * @return Resolves with the number of bytes successfully written to the file,
+   *         otherwise rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<unsigned long long> writeJSON(DOMString path, any value, optional WriteOptions options = {});
+  /**
+   * Moves the file from |sourcePath| to |destPath|, creating necessary parents.
+   * If |destPath| is a directory, then the source file will be moved into the
+   * destination directory.
+   *
+   * @param sourcePath An absolute file path identifying the file or directory
+   *                   to move.
+   * @param destPath   An absolute file path identifying the destination
+   *                   directory and/or file name.
+   *
+   * @return Resolves if the file is moved successfully, otherwise rejects with
+   *         a DOMException.
+   */
+  [NewObject]
+  Promise<undefined> move(DOMString sourcePath, DOMString destPath, optional MoveOptions options = {});
+  /**
+   * Removes a file or directory at |path| according to |options|.
+   *
+   * @param path An absolute file path identifying the file or directory to
+   *             remove.
+   *
+   * @return Resolves if the file is removed successfully, otherwise rejects
+   *         with a DOMException.
+   */
+  [NewObject]
+  Promise<undefined> remove(DOMString path, optional RemoveOptions options = {});
+  /**
+   * Creates a new directory at |path| according to |options|.
+   *
+   * @param path An absolute file path identifying the directory to create.
+   *
+   * @return Resolves if the directory is created successfully, otherwise
+   *         rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<undefined> makeDirectory(DOMString path, optional MakeDirectoryOptions options = {});
+  /**
+   * Obtains information about a file, such as size, modification dates, etc.
+   *
+   * @param path An absolute file path identifying the file or directory to
+   *             inspect.
+   *
+   * @return Resolves with a |FileInfo| object for the file at path, otherwise
+   *         rejects with a DOMException.
+   *
+   * @see FileInfo
+   */
+  [NewObject]
+  Promise<FileInfo> stat(DOMString path);
+  /**
+   * Copies a file or directory from |sourcePath| to |destPath| according to
+   * |options|.
+   *
+   * @param sourcePath An absolute file path identifying the source file to be
+   *                   copied.
+   * @param destPath   An absolute file path identifying the location for the
+   *                   copy.
+   *
+   * @return Resolves if the file was copied successfully, otherwise rejects
+   *         with a DOMException.
+   */
+  [NewObject]
+  Promise<undefined> copy(DOMString sourcePath, DOMString destPath, optional CopyOptions options = {});
+  /**
+   * Updates the access time for the file at |path|.
+   *
+   * @param path         An absolute file path identifying the file whose
+   *                     modification time is to be set. This file must exist
+   *                     and will not be created.
+   * @param modification An optional access time for the file expressed in
+   *                     milliseconds since the Unix epoch
+   *                     (1970-01-01T00:00:00Z). The current system time is used
+   *                     if this parameter is not provided.
+   *
+   * @return Resolves with the updated access time time expressed in
+   *         milliseconds since the Unix epoch, otherwise rejects with a
+   *         DOMException.
+   */
+  [NewObject]
+  Promise<long long> setAccessTime(DOMString path, optional long long access);
+  /**
+   * Updates the modification time for the file at |path|.
+   *
+   * @param path         An absolute file path identifying the file whose
+   *                     modification time is to be set. This file must exist
+   *                     and will not be created.
+   * @param modification An optional modification time for the file expressed in
+   *                     milliseconds since the Unix epoch
+   *                     (1970-01-01T00:00:00Z). The current system time is used
+   *                     if this parameter is not provided.
+   *
+   * @return Resolves with the updated modification time expressed in
+   *         milliseconds since the Unix epoch, otherwise rejects with a
+   *         DOMException.
+   */
+  [NewObject]
+  Promise<long long> setModificationTime(DOMString path, optional long long modification);
+  /**
+   * Retrieves a (possibly empty) list of immediate children of the directory at
+   * |path|.
+   *
+   * @param path An absolute file path.
+   *
+   * @return Resolves with a sequence of absolute file paths representing the
+   *         children of the directory at |path|, otherwise rejects with a
+   *         DOMException.
+   */
+  [NewObject]
+  Promise<sequence<DOMString>> getChildren(DOMString path, optional GetChildrenOptions options = {});
+  /**
+   * Set the permissions of the file at |path|.
+   *
+   * Windows does not make a distinction between user, group, and other
+   * permissions like UNICES do. If a permission flag is set for any of user,
+   * group, or other has a permission, then all users will have that
+   * permission. Additionally, Windows does not support setting the
+   * "executable" permission.
+   *
+   * @param path        An absolute file path
+   * @param permissions The UNIX file mode representing the permissions.
+   * @param honorUmask  If omitted or true, any UNIX file mode value is
+   *                    modified by the process umask. If false, the exact value
+   *                    of UNIX file mode will be applied. This value has no effect
+   *                    on Windows.
+   *
+   * @return Resolves if the permissions were set successfully, otherwise
+   *         rejects with a DOMException.
+   */
+  [NewObject]
+  Promise<undefined> setPermissions(DOMString path, unsigned long permissions, optional boolean honorUmask = true);
+  /**
+   * Return whether or not the file exists at the given path.
+   *
+   * @param path An absolute file path.
+   *
+   * @return A promise that resolves to whether or not the given file exists.
+   */
+  [NewObject]
+  Promise<boolean> exists(DOMString path);
+
+  /**
+   * Create a file with a unique name and return its path.
+   *
+   * @param parent An absolute path to the directory where the file is to be
+   *               created.
+   * @param prefix A prefix for the filename.
+   *
+   * @return A promise that resolves to a unique filename.
+   */
+  [NewObject]
+  Promise<DOMString> createUniqueFile(DOMString parent, DOMString prefix, optional unsigned long permissions = 0644);
+
+  /**
+   * Create a directory with a unique name and return its path.
+   *
+   * @param parent An absolute path to the directory where the file is to be
+   *               created.
+   * @param prefix A prefix for the directory name.
+   *
+   * @return A promise that resolves to a unique directory name.
+   */
+  [NewObject]
+  Promise<DOMString> createUniqueDirectory(DOMString parent, DOMString prefix, optional unsigned long permissions = 0755);
+
+  /**
+   * Compute the hash of a file as a hex digest.
+   *
+   * @param path   The absolute path of the file to hash.
+   * @param method The hashing method to use.
+   *
+   * @return A promise that resolves to the hex digest of the file's hash in lowercase.
+   */
+  [NewObject]
+  Promise<UTF8String> computeHexDigest(DOMString path, HashAlgorithm method);
+
+#if defined(XP_WIN)
+  /**
+   * Return the Windows-specific file attributes of the file at the given path.
+   *
+   * @param path An absolute file path.
+   *
+   * @return A promise that resolves to the Windows-specific file attributes.
+   */
+  [NewObject]
+  Promise<WindowsFileAttributes> getWindowsAttributes(DOMString path);
+
+  /**
+   * Set the Windows-specific file attributes of the file at the given path.
+   *
+   * @param path An absolute file path.
+   * @param attrs The attributes to set. Attributes will only be set if they are
+   *              |true| or |false| (i.e., |undefined| attributes are not
+   *              changed).
+   *
+   * @return A promise that resolves is the attributes were set successfully.
+   */
+  [NewObject]
+  Promise<undefined> setWindowsAttributes(DOMString path, optional WindowsFileAttributes attrs = {});
+#elif defined(XP_MACOSX)
+  /**
+   * Return whether or not the file has a specific extended attribute.
+   *
+   * @param path An absolute path.
+   * @param attr The attribute to check for.
+   *
+   * @return A promise that resolves to whether or not the file has an extended
+   *         attribute, or rejects with an error.
+   */
+  [NewObject]
+  Promise<boolean> hasMacXAttr(DOMString path, UTF8String attr);
+  /**
+   * Return the value of an extended attribute for a file.
+   *
+   * @param path An absolute path.
+   * @param attr The attribute to get the value of.
+   *
+   * @return A promise that resolves to the value of the extended attribute, or
+   *         rejects with an error.
+   */
+  [NewObject]
+  Promise<Uint8Array> getMacXAttr(DOMString path, UTF8String attr);
+  /**
+   * Set the extended attribute on a file.
+   *
+   * @param path  An absolute path.
+   * @param attr  The attribute to set.
+   * @param value The value of the attribute to set.
+   *
+   * @return A promise that resolves to whether or not the file has an extended
+   *         attribute, or rejects with an error.
+   */
+  [NewObject]
+  Promise<undefined> setMacXAttr(DOMString path, UTF8String attr, Uint8Array value);
+  /**
+   * Delete the extended attribute on a file.
+   *
+   * @param path An absolute path.
+   * @param attr The attribute to delete.
+   *
+   * @return A promise that resolves if the attribute was deleted, or rejects
+   *         with an error.
+   */
+  [NewObject]
+  Promise<undefined> delMacXAttr(DOMString path, UTF8String attr);
+#endif
+
+  /**
+   * Return a nsIFile whose parent directory exists. The parent directory of the
+   * file will be created off main thread if it does not already exist.
+   *
+   * @param components The path components. The first component must be an
+   *                   absolute path.
+   *
+   * @return A promise that resolves to an nsIFile for the requested file.
+   */
+  [NewObject]
+  Promise<nsIFile> getFile(DOMString... components);
+
+  /**
+   * Return an nsIFile corresponding to a directory. It will be created
+   * off-main-thread if it does not already exist.
+   *
+   * @param components The path components. The first component must be an
+   *                   absolute path.
+   *
+   * @return A promise that resolves to an nsIFile for the requested directory.
+   */
+  [NewObject]
+  Promise<nsIFile> getDirectory(DOMString... components);
+};
+
+[Exposed=Window]
+partial namespace IOUtils {
+  /**
+   * The async shutdown client for the profile-before-change shutdown phase.
+   */
+  [Throws]
+  readonly attribute any profileBeforeChange;
+
+  /**
+   * The async shutdown client for the profile-before-change-telemetry shutdown
+   * phase.
+   *
+   * ONLY telemetry should register blockers on this client.
+   */
+  [Throws]
+  readonly attribute any sendTelemetry;
+};
+
+[Exposed=Worker]
+partial namespace IOUtils {
+  /**
+   * Synchronously opens the file at |path|. This API is only available in workers.
+   *
+   * @param path An absolute file path.
+   *
+   * @return A |SyncReadFile| object for the file.
+   */
+  [Throws]
+  SyncReadFile openFileForSyncReading(DOMString path);
+
+#ifdef XP_UNIX
+  /**
+   * Launch a child process; uses `base::LaunchApp` from IPC.  (This WebIDL
+   * binding is currently Unix-only; it could also be supported on Windows
+   * but it would use u16-based strings, so it would basically be a separate
+   * copy of the bindings.)
+   *
+   * This interface was added for use by `Subprocess.sys.jsm`; other would-be
+   * callers may want to just use Subprocess instead of calling this directly.
+   *
+   * @param argv The command to run and its arguments.
+   * @param options Various parameters about how the child process is launched
+   *                and its initial environment.
+   *
+   * @return The process ID.  Note that various errors (e.g., the
+   *         executable to be launched doesn't exist) may not be
+   *         encountered until after the process is created, so a
+   *         successful return doesn't necessarily imply a successful
+   *         launch.
+   */
+  [Throws]
+  unsigned long launchProcess(sequence<UnixString> argv, LaunchOptions options);
+#endif
+};
+
+/**
+ * An object representing an open file, allowing parts of the file contents to be
+ * read synchronously. Only available in workers.
+ */
+[ChromeOnly, Exposed=Worker]
+interface SyncReadFile {
+  /**
+   * The file size, in bytes.
+   */
+  readonly attribute long long size;
+
+  /**
+   * Synchronously read |dest.length| bytes at offset |offset| into |dest|.
+   * Throws if the file has been closed already or if the read would be out-of-bounds.
+   *
+   * @param dest   A Uint8Array whose entire contents will be overwritten with
+   *               bytes read from the file.
+   * @param offset The file offset at which the read range begins. (The length of the
+   *               range is given by |dest.length|.)
+   */
+  [Throws]
+  undefined readBytesInto(Uint8Array dest, long long offset);
+
+  /**
+   * Close the file. Subsequent calls to readBytesInto will throw.
+   * If the file is not closed manually, it will be closed once this object is GC'ed.
+   */
+  undefined close();
+};
+
+/**
+ * Options to be passed to the |IOUtils.readUTF8| method.
+ */
+dictionary ReadUTF8Options {
+  /**
+   * If true, this option indicates that the file to be read is compressed with
+   * LZ4-encoding, and should be decompressed before the data is returned to
+   * the caller.
+   */
+  boolean decompress = false;
+};
+
+/**
+ * Options to be passed to the |IOUtils.read| method.
+ */
+dictionary ReadOptions : ReadUTF8Options {
+  /**
+   * The offset into the file to read from. If unspecified, the file will be read
+   * from the start.
+   */
+  unsigned long long offset = 0;
+
+  /**
+   * The max bytes to read from the file at path. If unspecified, the entire
+   * file will be read. This option is incompatible with |decompress|.
+   */
+  unsigned long? maxBytes = null;
+};
+
+/**
+ * Modes for writing to a file.
+ */
+enum WriteMode {
+  /**
+   * Overwrite the contents of the file.
+   *
+   * The file will be created if it does not exist.
+   */
+  "overwrite",
+  /**
+   * Append to the end of the file.
+   *
+   * This mode will refuse to create the file if it does not exist.
+   */
+  "append",
+  /**
+   * Append to the end of the file, or create it if it does not exist.
+   */
+  "appendOrCreate",
+  /**
+   * Create a new file.
+   *
+   * This mode will refuse to overwrite an existing file.
+   */
+  "create",
+};
+
+/**
+ * Options to be passed to the |IOUtils.write| and |writeUTF8|
+ * methods.
+ */
+dictionary WriteOptions {
+  /**
+   * If specified, backup the destination file to this path before writing.
+   */
+  DOMString backupFile;
+  /**
+   * If specified, write the data to a file at |tmpPath| instead of directly to
+   * the destination. Once the write is complete, the destination will be
+   * overwritten by a move. Specifying this option will make the write a little
+   * slower, but also safer.
+   */
+  DOMString tmpPath;
+  /**
+   * The mode used to write to the file.
+   */
+  WriteMode mode = "overwrite";
+  /**
+   * If true, force the OS to write its internal buffers to the disk.
+   * This is considerably slower for the whole system, but safer in case of
+   * an improper system shutdown (e.g. due to a kernel panic) or device
+   * disconnection before the buffers are flushed.
+   */
+  boolean flush = false;
+  /**
+   * If true, compress the data with LZ4-encoding before writing to the file.
+   */
+  boolean compress = false;
+};
+
+/**
+ * Options to be passed to the |IOUtils.move| method.
+ */
+dictionary MoveOptions {
+  /**
+   * If true, fail if the destination already exists.
+   */
+  boolean noOverwrite = false;
+};
+
+/**
+ * Options to be passed to the |IOUtils.remove| method.
+ */
+dictionary RemoveOptions {
+  /**
+   * If true, no error will be reported if the target file is missing.
+   */
+  boolean ignoreAbsent = true;
+  /**
+   * If true, and the target is a directory, recursively remove files.
+   */
+  boolean recursive = false;
+};
+
+/**
+ * Options to be passed to the |IOUtils.makeDirectory| method.
+ */
+dictionary MakeDirectoryOptions {
+  /**
+   * If true, create the directory and all necessary ancestors if they do not
+   * already exist. If false and any ancestor directories do not exist,
+   * |makeDirectory| will reject with an error.
+   */
+  boolean createAncestors = true;
+  /**
+   * If true, succeed even if the directory already exists (default behavior).
+   * Otherwise, fail if the directory already exists.
+   */
+  boolean ignoreExisting = true;
+  /**
+   * The file mode to create the directory with.
+   *
+   * This is ignored on Windows.
+   */
+  unsigned long permissions = 0755;
+
+};
+
+/**
+ * Options to be passed to the |IOUtils.copy| method.
+ */
+dictionary CopyOptions {
+  /**
+   * If true, fail if the destination already exists.
+   */
+  boolean noOverwrite = false;
+  /**
+   * If true, copy the source recursively.
+   */
+  boolean recursive = false;
+};
+
+/**
+ * Options to be passed to the |IOUtils.getChildren| method.
+ */
+dictionary GetChildrenOptions {
+  /**
+   * If true, no error will be reported if the target file is missing.
+   */
+  boolean ignoreAbsent = false;
+};
+
+/**
+ * Types of files that are recognized by the |IOUtils.stat| method.
+ */
+enum FileType { "regular", "directory", "other" };
+
+/**
+ * Basic metadata about a file.
+ */
+dictionary FileInfo {
+  /**
+   * The absolute path to the file on disk, as known when this file info was
+   * obtained.
+   */
+  DOMString path;
+
+  /**
+   * Identifies if the file at |path| is a regular file, directory, or something
+   * something else.
+   */
+  FileType type;
+
+  /**
+   * If this represents a regular file, the size of the file in bytes.
+   * Otherwise, -1.
+   */
+  long long size;
+
+  /**
+   * The timestamp of file creation, represented in milliseconds since Epoch
+   * (1970-01-01T00:00:00.000Z).
+   *
+   * This is only available on MacOS and Windows.
+   */
+  long long creationTime;
+
+  /**
+   * The timestmp of last file accesss, represented in milliseconds since Epoch
+   * (1970-01-01T00:00:00.000Z).
+   */
+  long long lastAccessed;
+
+  /**
+   * The timestamp of the last file modification, represented in milliseconds
+   * since Epoch (1970-01-01T00:00:00.000Z).
+   */
+  long long lastModified;
+
+  /**
+   * The permissions of the file, expressed as a UNIX file mode.
+   *
+   * NB: Windows does not make a distinction between user, group, and other
+   * permissions like UNICES do. The user, group, and other parts will always
+   * be identical on Windows.
+   */
+  unsigned long permissions;
+};
+
+/**
+ * The supported hash algorithms for |IOUtils.hashFile|.
+ */
+enum HashAlgorithm { "sha1", "sha256", "sha384", "sha512" };
+
+#ifdef XP_WIN
+/**
+ * Windows-specific file attributes.
+ */
+dictionary WindowsFileAttributes {
+  /**
+   * Whether or not the file is read-only.
+   */
+  boolean readOnly;
+  /**
+   * Whether or not the file is hidden.
+   */
+  boolean hidden;
+  /**
+   * Whether or not the file is classified as a system file.
+   */
+  boolean system;
+};
+#endif
+
+#ifdef XP_UNIX
+/**
+ * Used where the POSIX API allows an arbitrary byte string but in
+ * practice it's usually UTF-8, so JS strings are accepted for
+ * convenience.
+ */
+typedef (UTF8String or Uint8Array) UnixString;
+
+/**
+ * Options for the `launchApp` method.  See also `base::LaunchOptions`
+ * in C++.
+ */
+dictionary LaunchOptions {
+  /**
+   * The environment variables, as a sequence of `NAME=value` strings.
+   * (The underlying C++ code can also inherit the current environment
+   * with optional changes; that feature could be added here if needed.)
+   */
+  required sequence<UnixString> environment;
+
+  /**
+   * The initial current working directory.
+   */
+  UnixString workdir;
+
+  /**
+   * File descriptors to pass to the child process.  Any fds not
+   * mentioned here, other than stdin/out/err, will not be inherited
+   * even if they aren't marked close-on-exec.
+   */
+  sequence<FdMapping> fdMap;
+
+  /**
+   * On macOS 10.14+, disclaims responsibility for the child process
+   * with respect to privacy/security permission prompts and
+   * decisions.  Ignored if not supported by the OS.
+   */
+  boolean disclaim = false;
+};
+
+/**
+ * Describes a file descriptor to give to the child process.
+ */
+dictionary FdMapping {
+  /**
+   * The fd in the parent process to pass.  This must remain open during
+   * the call to `launchApp` but can be closed after it returns (or throws).
+   */
+  required unsigned long src;
+
+  /**
+   * The fd number to map it to in the child process.
+   */
+  required unsigned long dst;
+};
+#endif
diff --git a/dom/chrome-webidl/ImageText.webidl b/dom/chrome-webidl/ImageText.webidl
new file mode 100644
index 0000000000..262a82b353
--- /dev/null
+++ b/dom/chrome-webidl/ImageText.webidl
@@ -0,0 +1,29 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * Text that has been extracted from an image using an image recognition API.
+ */
+dictionary ImageText {
+  /**
+   * A scalar value representing how confident the text recognition model was in the
+   * produced result.
+   */
+  required float confidence;
+
+  /**
+   * The recognized text.
+   */
+  required DOMString string;
+
+  /**
+   * A DOMQuad representing the bounds of the text. This can be a free-form four pointed
+   * polygon, and not necessarily a square or parallelogram. It does not actually contain
+   * CSSPixels, but the points are ranged 0-1 and represent a ratio of the width / height
+   * of the source image.
+   */
+  required DOMQuad quad;
+};
diff --git a/dom/chrome-webidl/InspectorUtils.webidl b/dom/chrome-webidl/InspectorUtils.webidl
new file mode 100644
index 0000000000..1a17250dc0
--- /dev/null
+++ b/dom/chrome-webidl/InspectorUtils.webidl
@@ -0,0 +1,188 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * A collection of utility methods for use by devtools.
+ *
+ * See InspectorUtils.h for documentation on these methods.
+ */
+[Func="nsContentUtils::IsCallerChromeOrFuzzingEnabled",
+ Exposed=Window]
+namespace InspectorUtils {
+  // documentOnly tells whether user and UA sheets should get included.
+  sequence<StyleSheet> getAllStyleSheets(Document document, optional boolean documentOnly = false);
+  sequence<CSSStyleRule> getCSSStyleRules(
+    Element element,
+    optional [LegacyNullToEmptyString] DOMString pseudo = "",
+    optional boolean relevantLinkVisited = false);
+  unsigned long getRuleLine(CSSRule rule);
+  unsigned long getRuleColumn(CSSRule rule);
+  unsigned long getRelativeRuleLine(CSSRule rule);
+  boolean hasRulesModifiedByCSSOM(CSSStyleSheet sheet);
+  unsigned long getSelectorCount(CSSStyleRule rule);
+  [Throws] UTF8String getSelectorText(CSSStyleRule rule,
+                                      unsigned long selectorIndex);
+  [Throws] unsigned long long getSpecificity(CSSStyleRule rule,
+                                             unsigned long selectorIndex);
+  [Throws] boolean selectorMatchesElement(
+      Element element,
+      CSSStyleRule rule,
+      unsigned long selectorIndex,
+      optional [LegacyNullToEmptyString] DOMString pseudo = "",
+      optional boolean includeVisitedStyle = false);
+  boolean isInheritedProperty(UTF8String property);
+  sequence<DOMString> getCSSPropertyNames(optional PropertyNamesOptions options = {});
+  sequence<PropertyPref> getCSSPropertyPrefs();
+  [Throws] sequence<DOMString> getCSSValuesForProperty(UTF8String property);
+  [Throws] DOMString rgbToColorName(octet r, octet g, octet b);
+  InspectorRGBATuple? colorToRGBA(UTF8String colorString, optional Document? doc = null);
+  boolean isValidCSSColor(UTF8String colorString);
+  [Throws] sequence<DOMString> getSubpropertiesForCSSProperty(UTF8String property);
+  [Throws] boolean cssPropertyIsShorthand(UTF8String property);
+
+  [Throws] boolean cssPropertySupportsType(UTF8String property, InspectorPropertyType type);
+
+  // A version of CSS.supports that allows you to set UA or chrome context.
+  boolean supports(UTF8String conditionText, optional SupportsOptions options = {});
+
+  boolean isIgnorableWhitespace(CharacterData dataNode);
+  Node? getParentForNode(Node node, boolean showingAnonymousContent);
+  [NewObject] NodeList getChildrenForNode(Node node,
+                                          boolean showingAnonymousContent);
+  [Throws] boolean setContentState(Element element, unsigned long long state);
+  [Throws] boolean removeContentState(
+      Element element,
+      unsigned long long state,
+      optional boolean clearActiveDocument = false);
+  unsigned long long getContentState(Element element);
+
+  // Get the font face(s) actually used to render the text in /range/,
+  // as a collection of InspectorFontFace objects (below).
+  // If /maxRanges/ is greater than zero, each InspectorFontFace will record
+  // up to /maxRanges/ fragments of content that used the face, for the caller
+  // to access via its .ranges attribute.
+  [NewObject, Throws] sequence<InspectorFontFace> getUsedFontFaces(
+      Range range,
+      optional unsigned long maxRanges = 0,
+      optional boolean skipCollapsedWhitespace = true);
+
+  sequence<DOMString> getCSSPseudoElementNames();
+  undefined addPseudoClassLock(Element element,
+                               DOMString pseudoClass,
+                               optional boolean enabled = true);
+  undefined removePseudoClassLock(Element element, DOMString pseudoClass);
+  boolean hasPseudoClassLock(Element element, DOMString pseudoClass);
+  undefined clearPseudoClassLocks(Element element);
+  [Throws] undefined parseStyleSheet(CSSStyleSheet sheet, UTF8String input);
+  boolean isCustomElementName([LegacyNullToEmptyString] DOMString name,
+                              DOMString? namespaceURI);
+
+  boolean isElementThemed(Element element);
+
+  Element? containingBlockOf(Element element);
+
+  [NewObject] NodeList getOverflowingChildrenOfElement(Element element);
+};
+
+dictionary SupportsOptions {
+  boolean userAgent = false;
+  boolean chrome = false;
+  boolean quirks = false;
+};
+
+dictionary PropertyNamesOptions {
+  boolean includeAliases = false;
+  boolean includeShorthands = true;
+  boolean includeExperimentals = false;
+};
+
+dictionary PropertyPref {
+  required DOMString name;
+  required DOMString pref;
+};
+
+dictionary InspectorRGBATuple {
+  /*
+   * NOTE: This tuple is in the normal 0-255-sized RGB space but can be
+   * fractional and may extend outside the 0-255 range.
+   *
+   * a is in the range 0 - 1.
+   */
+  double r = 0;
+  double g = 0;
+  double b = 0;
+  double a = 1;
+};
+
+// Any update to this enum should probably also update
+// devtools/shared/css/constants.js
+enum InspectorPropertyType {
+  "color",
+  "gradient",
+  "timing-function",
+};
+
+dictionary InspectorVariationAxis {
+  required DOMString tag;
+  required DOMString name;
+  required float minValue;
+  required float maxValue;
+  required float defaultValue;
+};
+
+dictionary InspectorVariationValue {
+  required DOMString axis;
+  required float value;
+};
+
+dictionary InspectorVariationInstance {
+  required DOMString name;
+  required sequence<InspectorVariationValue> values;
+};
+
+dictionary InspectorFontFeature {
+  required DOMString tag;
+  required DOMString script;
+  required DOMString languageSystem;
+};
+
+[Func="nsContentUtils::IsCallerChromeOrFuzzingEnabled",
+ Exposed=Window]
+interface InspectorFontFace {
+  // An indication of how we found this font during font-matching.
+  // Note that the same physical font may have been found in multiple ways within a range.
+  readonly attribute boolean fromFontGroup;
+  readonly attribute boolean fromLanguagePrefs;
+  readonly attribute boolean fromSystemFallback;
+
+  // available for all fonts
+  readonly attribute DOMString name; // full font name as obtained from the font resource
+  readonly attribute DOMString CSSFamilyName; // a family name that could be used in CSS font-family
+                                              // (not necessarily the actual name that was used,
+                                              // due to aliases, generics, localized names, etc)
+  readonly attribute DOMString CSSGeneric; // CSS generic (serif, sans-serif, etc) that was mapped
+                                           // to this font, if any (frequently empty!)
+
+  [NewObject,Throws] sequence<InspectorVariationAxis> getVariationAxes();
+  [NewObject,Throws] sequence<InspectorVariationInstance> getVariationInstances();
+  [NewObject,Throws] sequence<InspectorFontFeature> getFeatures();
+
+  // A list of Ranges of text rendered with this face.
+  // This will list the first /maxRanges/ ranges found when InspectorUtils.getUsedFontFaces
+  // was called (so it will be empty unless a non-zero maxRanges argument was passed).
+  // Note that this indicates how the document was rendered at the time of calling
+  // getUsedFontFaces; it does not reflect any subsequent modifications, so if styles
+  // have been modified since calling getUsedFontFaces, it may no longer be accurate.
+  [Constant,Cached]  readonly attribute sequence<Range> ranges;
+
+  // meaningful only when the font is a user font defined using @font-face
+  readonly attribute CSSFontFaceRule? rule; // null if no associated @font-face rule
+  readonly attribute long srcIndex; // index in the rule's src list, -1 if no @font-face rule
+  readonly attribute DOMString URI; // empty string if not a downloaded font, i.e. local
+  readonly attribute DOMString localName; // empty string  if not a src:local(...) rule
+  readonly attribute DOMString format; // as per http://www.w3.org/TR/css3-webfonts/#referencing
+  readonly attribute DOMString metadata; // XML metadata from WOFF file (if any)
+};
diff --git a/dom/chrome-webidl/IteratorResult.webidl b/dom/chrome-webidl/IteratorResult.webidl
new file mode 100644
index 0000000000..b066ab409b
--- /dev/null
+++ b/dom/chrome-webidl/IteratorResult.webidl
@@ -0,0 +1,15 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+/**
+ * A dictionary which represents the result of a call to a next() method on a
+ * JS iterator object.
+ */
+[GenerateConversionToJS, GenerateInit]
+dictionary IteratorResult {
+  required boolean done;
+  any value;
+};
diff --git a/dom/chrome-webidl/JSActor.webidl b/dom/chrome-webidl/JSActor.webidl
new file mode 100644
index 0000000000..db73fb7994
--- /dev/null
+++ b/dom/chrome-webidl/JSActor.webidl
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+interface mixin JSActor {
+    [Throws]
+    undefined sendAsyncMessage(DOMString messageName,
+                               optional any obj);
+
+    [NewObject]
+    Promise<any> sendQuery(DOMString messageName,
+                           optional any obj);
+
+    readonly attribute UTF8String name;
+};
+
+/**
+ * WebIDL callback interface version of the nsIObserver interface for use when
+ * calling the observe method on JSActors.
+ *
+ * NOTE: This isn't marked as ChromeOnly, as it has no interface object, and
+ * thus cannot be conditionally exposed.
+ */
+[Exposed=Window]
+callback interface MozObserverCallback {
+  undefined observe(nsISupports subject, ByteString topic, DOMString? data);
+};
+
+/**
+ * WebIDL callback interface calling the `didDestroy`, and
+ * `actorCreated` methods on JSActors.
+ */
+[MOZ_CAN_RUN_SCRIPT_BOUNDARY]
+callback MozJSActorCallback = undefined();
+
+/**
+ * The didDestroy method, if present, will be called after the actor is no
+ * longer able to receive any more messages.
+ * The actorCreated method, if present, will be called immediately after the
+ * actor has been created and initialized.
+ */
+[GenerateInit]
+dictionary MozJSActorCallbacks {
+  [ChromeOnly] MozJSActorCallback didDestroy;
+  [ChromeOnly] MozJSActorCallback actorCreated;
+};
diff --git a/dom/chrome-webidl/JSProcessActor.webidl b/dom/chrome-webidl/JSProcessActor.webidl
new file mode 100644
index 0000000000..13a7062427
--- /dev/null
+++ b/dom/chrome-webidl/JSProcessActor.webidl
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * An actor architecture designed to allow compositional parent/content
+ * communications. The lifetime of a JSProcessActor{Child, Parent} is the `ContentParent`
+ * (for the parent-side) / `ContentChild` (for the child-side).
+ */
+
+interface nsISupports;
+
+/**
+ * Base class for parent-side actor.
+ */
+[ChromeOnly, Exposed=Window]
+interface JSProcessActorParent {
+  [ChromeOnly]
+  constructor();
+
+  readonly attribute nsIDOMProcessParent manager;
+};
+JSProcessActorParent includes JSActor;
+
+[ChromeOnly, Exposed=Window]
+interface JSProcessActorChild {
+  [ChromeOnly]
+  constructor();
+
+  readonly attribute nsIDOMProcessChild manager;
+};
+JSProcessActorChild includes JSActor;
+
+
+/**
+ * Used by `ChromeUtils.registerProcessActor()` to register actors.
+ */
+dictionary ProcessActorOptions {
+  /**
+   * An array of remote type which restricts the actor is allowed to instantiate
+   * in specific process type. If this is defined, the prefix of process type
+   * matches the remote type by prefix match is allowed to instantiate, ex: if
+   * Fission is enabled, the prefix of process type will be `webIsolated`, it
+   * can prefix match remote type either `web` or `webIsolated`. If not passed,
+   * all content processes are allowed to instantiate the actor.
+   */
+  sequence<UTF8String> remoteTypes;
+
+  /**
+   * If this is set to `true`, allow this actor to be created for the parent
+   * process.
+   */
+  boolean includeParent = false;
+
+  /** This fields are used for configuring individual sides of the actor. */
+  ProcessActorSidedOptions parent;
+  ProcessActorChildOptions child;
+};
+
+dictionary ProcessActorSidedOptions {
+  /**
+   * The JSM path which should be loaded for the actor on this side.
+   *
+   * Mutually exclusive with `esModuleURI`.
+   *
+   * If neither this nor `esModuleURI` is passed, the specified side cannot receive
+   * messages, but may send them using `sendAsyncMessage` or `sendQuery`.
+   */
+  ByteString moduleURI;
+
+  /**
+   * The ESM path which should be loaded for the actor on this side.
+   *
+   * Mutually exclusive with `moduleURI`.
+   *
+   * If neither this nor `moduleURI` is passed, the specified side cannot
+   * receive messages, but may send them using `sendAsyncMessage` or
+   * `sendQuery`.
+   */
+  ByteString esModuleURI;
+};
+
+dictionary ProcessActorChildOptions : ProcessActorSidedOptions {
+  /**
+   * An array of observer topics to listen to. An observer will be added for each
+   * topic in the list.
+   *
+   * Unlike for JSWindowActor, observers are always invoked, and do not need to
+   * pass an inner or outer window as subject.
+   */
+  sequence<ByteString> observers;
+};
diff --git a/dom/chrome-webidl/JSWindowActor.webidl b/dom/chrome-webidl/JSWindowActor.webidl
new file mode 100644
index 0000000000..767b4854c5
--- /dev/null
+++ b/dom/chrome-webidl/JSWindowActor.webidl
@@ -0,0 +1,186 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * An actor architecture designed to allow compositional parent/content
+ * communications. The lifetime of a JSWindowActor{Child, Parent} is the `WindowGlobalParent`
+ * (for the parent-side) / `WindowGlobalChild` (for the child-side).
+ *
+ * See https://firefox-source-docs.mozilla.org/dom/ipc/jsactors.html for
+ * more details on how to use this architecture.
+ */
+
+interface nsISupports;
+
+[ChromeOnly, Exposed=Window]
+interface JSWindowActorParent {
+  [ChromeOnly]
+  constructor();
+
+  /**
+   * Actor initialization occurs after the constructor is called but before the
+   * first message is delivered. Until the actor is initialized, accesses to
+   * manager will fail.
+   */
+  readonly attribute WindowGlobalParent? manager;
+
+  /**
+   * The WindowContext associated with this JSWindowActorParent. For
+   * JSWindowActorParent this is identical to `manager`, but is also exposed as
+   * `windowContext` for consistency with `JSWindowActorChild`. Until the actor
+   * is initialized, accesses to windowContext will fail.
+   */
+  readonly attribute WindowContext? windowContext;
+
+  [Throws]
+  readonly attribute CanonicalBrowsingContext? browsingContext;
+};
+JSWindowActorParent includes JSActor;
+
+[ChromeOnly, Exposed=Window]
+interface JSWindowActorChild {
+  [ChromeOnly]
+  constructor();
+
+  /**
+   * Actor initialization occurs after the constructor is called but before the
+   * first message is delivered. Until the actor is initialized, accesses to
+   * manager will fail.
+   */
+  readonly attribute WindowGlobalChild? manager;
+
+  /**
+   * The WindowContext associated with this JSWindowActorChild. Until the actor
+   * is initialized, accesses to windowContext will fail.
+   */
+  readonly attribute WindowContext? windowContext;
+
+  [Throws]
+  readonly attribute Document? document;
+
+  [Throws]
+  readonly attribute BrowsingContext? browsingContext;
+
+  [Throws]
+  readonly attribute nsIDocShell? docShell;
+
+  /**
+   * NOTE: As this returns a window proxy, it may not be currently referencing
+   * the document associated with this JSWindowActor. Generally prefer using
+   * `document`.
+   */
+  [Throws]
+  readonly attribute WindowProxy? contentWindow;
+};
+JSWindowActorChild includes JSActor;
+
+/**
+ * Used by ChromeUtils.registerWindowActor() to register JS window actor.
+ */
+dictionary WindowActorOptions {
+  /**
+   * If this is set to `true`, allow this actor to be created for subframes,
+   * and not just toplevel window globals.
+   */
+  boolean allFrames = false;
+
+  /**
+   * If this is set to `true`, allow this actor to be created for window
+   * globals loaded in chrome browsing contexts, such as those used to load the
+   * tabbrowser.
+   */
+  boolean includeChrome = false;
+
+  /**
+   * An array of URL match patterns (as accepted by the MatchPattern
+   * class in MatchPattern.webidl) which restrict which pages the actor
+   * may be instantiated for. If this is defined, only documents URL which match
+   * are allowed to have the given actor created for them. Other
+   * documents will fail to have their actor constructed, returning nullptr.
+   */
+  sequence<DOMString> matches;
+
+  /**
+   * An array of remote type which restricts the actor is allowed to instantiate
+   * in specific process type. If this is defined, the prefix of process type
+   * matches the remote type by prefix match is allowed to instantiate, ex: if
+   * Fission is enabled, the prefix of process type will be `webIsolated`, it
+   * can prefix match remote type either `web` or `webIsolated`. If not passed,
+   * all content processes are allowed to instantiate the actor.
+   */
+  sequence<UTF8String> remoteTypes;
+
+  /**
+   * An array of MessageManagerGroup values which restrict which type
+   * of browser elements the actor is allowed to be loaded within.
+   */
+  sequence<DOMString> messageManagerGroups;
+
+  /** This fields are used for configuring individual sides of the actor. */
+  WindowActorSidedOptions parent;
+  WindowActorChildOptions child;
+};
+
+dictionary WindowActorSidedOptions {
+  /**
+   * The JSM path which should be loaded for the actor on this side.
+   *
+   * Mutually exclusive with `esModuleURI`.
+   *
+   * If neither this nor `esModuleURI` is passed, the specified side cannot receive
+   * messages, but may send them using `sendAsyncMessage` or `sendQuery`.
+   */
+  ByteString moduleURI;
+
+  /**
+   * The ESM path which should be loaded for the actor on this side.
+   *
+   * Mutually exclusive with `moduleURI`.
+   *
+   * If neither this nor `moduleURI` is passed, the specified side cannot
+   * receive messages, but may send them using `sendAsyncMessage` or
+   * `sendQuery`.
+   */
+  ByteString esModuleURI;
+};
+
+dictionary WindowActorEventListenerOptions : AddEventListenerOptions {
+  /**
+   * If this attribute is set to true (the default), this event will cause the
+   * actor to be created when it is fired. If the attribute is set false, the
+   * actor will not receive the event unless it had already been created through
+   * some other mechanism.
+   *
+   * This should be set to `false` for event listeners which are only intended
+   * to perform cleanup operations, and will have no effect if the actor doesn't
+   * already exist.
+   */
+  boolean createActor = true;
+};
+
+dictionary WindowActorChildOptions : WindowActorSidedOptions {
+  /**
+   * Events which this actor wants to be listening to. When these events fire,
+   * it will trigger actor creation, and then forward the event to the actor.
+   *
+   * NOTE: Listeners are not attached for windows loaded in chrome docshells.
+   *
+   * NOTE: `once` option is not support due to we register listeners in a shared
+   * location.
+   */
+  record<DOMString, WindowActorEventListenerOptions> events;
+
+ /**
+  * An array of observer topics to listen to. An observer will be added for each
+  * topic in the list.
+  *
+  * Observer notifications in the list use nsGlobalWindowInner or
+  * nsGlobalWindowOuter object as their subject, and the events will only be
+  * dispatched to the corresponding window actor. If additional observer
+  * notification's subjects are needed, please file a bug for that.
+  */
+  sequence<ByteString> observers;
+};
diff --git a/dom/chrome-webidl/L10nOverlays.webidl b/dom/chrome-webidl/L10nOverlays.webidl
new file mode 100644
index 0000000000..afe96cc58b
--- /dev/null
+++ b/dom/chrome-webidl/L10nOverlays.webidl
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+dictionary L10nOverlaysError {
+  short code;
+  DOMString translatedElementName;
+  DOMString sourceElementName;
+  DOMString l10nName;
+};
+
+[ChromeOnly,
+ Exposed=Window]
+namespace L10nOverlays {
+  const unsigned short ERROR_UNKNOWN = 1;
+  const unsigned short ERROR_FORBIDDEN_TYPE = 2;
+  const unsigned short ERROR_NAMED_ELEMENT_MISSING = 3;
+  const unsigned short ERROR_NAMED_ELEMENT_TYPE_MISMATCH = 4;
+  const unsigned short ERROR_TRANSLATED_ELEMENT_DISCONNECTED = 5;
+  const unsigned short ERROR_TRANSLATED_ELEMENT_DISALLOWED_DOM = 6;
+
+  sequence<L10nOverlaysError>? translateElement(Element element, optional L10nMessage translation = {});
+};
diff --git a/dom/chrome-webidl/L10nRegistry.webidl b/dom/chrome-webidl/L10nRegistry.webidl
new file mode 100644
index 0000000000..81932b2cd7
--- /dev/null
+++ b/dom/chrome-webidl/L10nRegistry.webidl
@@ -0,0 +1,180 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+dictionary L10nFileSourceMockFile {
+  required UTF8String path;
+  required UTF8String source;
+};
+
+enum L10nFileSourceHasFileStatus {
+    "present",
+    "missing",
+    "unknown"
+};
+
+dictionary FileSourceOptions {
+  FluentBundleAddResourceOptions addResourceOptions = {};
+};
+
+/**
+ * A `ResourceId` refers to a localization resource that is either required
+ * or optional. The default for a `ResourceId` is that the resource is required.
+ *
+ * If a required resource is missing for a given locale, then the L10nRegistry
+ * will not generate a bundle for that locale, because the resource is required
+ * to be present in order for the bundle to be considered valid.
+ *
+ * If an optional resource is missing for a given locale, then the L10nRegistry
+ * will still generate a bundle for that locale, but entries for the missing
+ * optional resource will be missing in the bundle.
+ *
+ * It is recommended to only use this sparingly, since marking many resources as
+ * optional will increase the state space that the L10nRegistry solver has to cover,
+ * and it will have a negative impact on performance.
+ *
+ * We should also strive to have valid resources for all supported locales, so using
+ * optional resources should be reserved for exceptional circumstances such as
+ * experimental features and features under development.
+ */
+dictionary ResourceId {
+  required UTF8String path;
+  boolean _optional = false;
+};
+
+typedef (UTF8String or ResourceId) L10nResourceId;
+
+/**
+ * The interface represents a single source location for
+ * the registry.
+ *
+ * Examples of sources are:
+ *  * Toolkit omni.ja Localization Directory
+ *  * Browser omni.ja Localization Directory
+ *  * Language Pack Toolkit Localization Directory
+ *  * Language Pack Browser Localization Directory
+ */
+[ChromeOnly,
+ Exposed=Window]
+interface L10nFileSource {
+  /**
+   * The `name` is the name of the `L10nFileSource`.
+   *
+   * The `metaSource` is the name of the package that contains the
+   * `L10nFileSource`, e.g. `app` for sources packaged with the browser, or
+   * `langpack` for sources packaged in an addon.
+   *
+   * The `locales` is a list of locales for which resources are contained in
+   * the `L10nFileSource`.
+   *
+   * The `prePath` is the path prefix for files contained in the `L10nFileSource`.
+   *
+   * Optional argument `index` can be used to provide a list
+   * of files available in the source.
+   *
+   * This is particularly useful for custom file sources which
+   * provide a small number of known override files allowing the
+   * registry to avoid trying I/O on the source for all
+   * files not available in the source.
+   */
+  [Throws]
+  constructor(UTF8String name, UTF8String metaSource, sequence<UTF8String> locales, UTF8String prePath, optional FileSourceOptions options = {}, optional sequence<UTF8String> index);
+
+  /**
+   * Tests may want to introduce custom file sources and
+   * register them in a custom `L10nRegistry` to mock
+   * behavior of using localization with test file sources.
+   *
+   * # Example:
+   *
+   * ```
+   * let fs = [
+   *   {
+   *     "path": "/localization/en-US/test.ftl",
+   *     "source": "key = Hello World!",
+   *   }
+   * ];
+   * let mockSource = L10nFileSource.createMock("mock", "app", ["en-US"], "/localization/{locale}/", fs);
+   *
+   * let reg = new L10nRegistry();
+   * reg.registerSources([mockSource]);
+   *
+   * let loc = new Localization(["test.ftl"], reg);
+   * let value = await loc.formatValue("key");
+   * assert(value, "Hello World!");
+   * ```
+   */
+  [Throws]
+  static L10nFileSource createMock(UTF8String name, UTF8String metasource, sequence<UTF8String> locales, UTF8String prePath, sequence<L10nFileSourceMockFile> fs);
+
+  readonly attribute UTF8String name;
+  readonly attribute UTF8String metaSource;
+  [Pure, Cached, Frozen]
+  readonly attribute sequence<UTF8String> locales;
+  /**
+   * `prePath` is the root path used together with a relative path to construct the full path used to retrieve a file
+   * out of a file source.
+   *
+   * The `prePath` will usually contain a placeholder `{locale}` which gets replaced with a given locale.
+   */
+  readonly attribute UTF8String prePath;
+  [Pure, Cached, Frozen]
+  readonly attribute sequence<UTF8String>? index;
+
+  [Throws]
+  L10nFileSourceHasFileStatus hasFile(UTF8String locale, UTF8String path);
+  [NewObject]
+  Promise<FluentResource?> fetchFile(UTF8String locale, UTF8String path);
+  [Throws]
+  FluentResource? fetchFileSync(UTF8String locale, UTF8String path);
+};
+
+dictionary FluentBundleIteratorResult
+{
+  required FluentBundle? value;
+  required boolean done;
+};
+
+[LegacyNoInterfaceObject, Exposed=Window]
+interface FluentBundleIterator {
+  FluentBundleIteratorResult next();
+  [Alias="@@iterator"] FluentBundleIterator values();
+};
+
+[LegacyNoInterfaceObject, Exposed=Window]
+interface FluentBundleAsyncIterator {
+  [NewObject]
+  Promise<FluentBundleIteratorResult> next();
+  [Alias="@@asyncIterator"] FluentBundleAsyncIterator values();
+};
+
+dictionary L10nRegistryOptions {
+  FluentBundleOptions bundleOptions = {};
+};
+
+[ChromeOnly, Exposed=Window]
+interface L10nRegistry {
+  constructor(optional L10nRegistryOptions aOptions = {});
+
+  static L10nRegistry getInstance();
+
+  sequence<UTF8String> getAvailableLocales();
+
+  undefined registerSources(sequence<L10nFileSource> aSources);
+  undefined updateSources(sequence<L10nFileSource> aSources);
+  undefined removeSources(sequence<UTF8String> aSources);
+
+  [Throws]
+  boolean hasSource(UTF8String aName);
+  [Throws]
+  L10nFileSource? getSource(UTF8String aName);
+  sequence<UTF8String> getSourceNames();
+  undefined clearSources();
+
+  [Throws, NewObject]
+  FluentBundleIterator generateBundlesSync(sequence<UTF8String> aLocales, sequence<L10nResourceId> aResourceIds);
+
+  [Throws, NewObject]
+  FluentBundleAsyncIterator generateBundles(sequence<UTF8String> aLocales, sequence<L10nResourceId> aResourceIds);
+};
diff --git a/dom/chrome-webidl/MatchGlob.webidl b/dom/chrome-webidl/MatchGlob.webidl
new file mode 100644
index 0000000000..91554d21c4
--- /dev/null
+++ b/dom/chrome-webidl/MatchGlob.webidl
@@ -0,0 +1,26 @@
+/* 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/. */
+
+/**
+ * Represents a simple glob pattern matcher. Any occurrence of "*" in the glob
+ * pattern matches any literal string of characters in the string being
+ * compared. Additionally, if created with `allowQuestion = true`, any
+ * occurrence of "?" in the glob matches any single literal character.
+ */
+[ChromeOnly, Exposed=Window]
+interface MatchGlob {
+  [Throws]
+  constructor(UTF8String glob, optional boolean allowQuestion = true);
+
+  /**
+   * Returns true if the string matches the glob.
+   */
+  boolean matches(UTF8String string);
+
+  /**
+   * The glob string this MatchGlob represents.
+   */
+  [Constant]
+  readonly attribute UTF8String glob;
+};
diff --git a/dom/chrome-webidl/MatchPattern.webidl b/dom/chrome-webidl/MatchPattern.webidl
new file mode 100644
index 0000000000..4e75d39ba2
--- /dev/null
+++ b/dom/chrome-webidl/MatchPattern.webidl
@@ -0,0 +1,150 @@
+/* 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/. */
+
+interface Cookie;
+interface URI;
+
+/**
+ * A URL match pattern as used by the WebExtension and Chrome extension APIs.
+ *
+ * A match pattern is a string with one of the following formats:
+ *
+ *  - "<all_urls>"
+ *    The literal string "<all_urls>" matches any URL with a supported
+ *    protocol.
+ *
+ *  - <proto>://<host>/<path>
+ *    A URL pattern with the following placeholders:
+ *
+ *    - <proto>
+ *      The protocol to match, or "*" to match either "http" or "https".
+ *    - <host>
+ *      The hostname to match. May be either a complete, literal hostname to
+ *      match a specific host, the wildcard character "*", to match any host,
+ *      or a subdomain pattern, with "*." followed by a domain name, to match
+ *      that domain name or any subdomain thereof.
+ *    - <path>
+ *      A glob pattern for paths to match. A "*" may appear anywhere within
+ *      the path, and will match any string of characters. If no "*" appears,
+ *      the URL path must exactly match the pattern path.
+ */
+[ChromeOnly, Exposed=Window]
+interface MatchPattern {
+  [Throws]
+  constructor(DOMString pattern, optional MatchPatternOptions options = {});
+
+  /**
+   * Returns true if the given URI matches the pattern.
+   *
+   * If explicit is true, only explicit domain matches, without wildcards, are
+   * considered.
+   */
+  [Throws]
+  boolean matches(URI uri, optional boolean explicit = false);
+
+  [Throws]
+  boolean matches(DOMString url, optional boolean explicit = false);
+
+  /**
+   * Returns true if a URL exists which a) would be able to access the given
+   * cookie, and b) would be matched by this match pattern.
+   */
+  boolean matchesCookie(Cookie cookie);
+
+  /**
+   * Returns true if this pattern will match any host which would be matched
+   * by the given pattern.
+   */
+  boolean subsumes(MatchPattern pattern);
+
+  /**
+   * Returns true if this pattern will match any host which would be matched
+   * by the given pattern, ignoring the scheme.
+   */
+  boolean subsumesDomain(MatchPattern pattern);
+
+  /**
+   * Returns true if there is any host which would be matched by both this
+   * pattern and the given pattern.
+   */
+  boolean overlaps(MatchPattern pattern);
+
+  /**
+   * The match pattern string represented by this pattern.
+   */
+  [Constant]
+  readonly attribute DOMString pattern;
+};
+
+/**
+ * A set of MatchPattern objects, which implements the MatchPattern API and
+ * matches when any of its sub-patterns matches.
+ */
+[ChromeOnly, Exposed=Window]
+interface MatchPatternSet {
+  [Throws]
+  constructor(sequence<(DOMString or MatchPattern)> patterns, optional MatchPatternOptions options = {});
+
+  /**
+   * Returns true if the given URI matches any sub-pattern.
+   *
+   * If explicit is true, only explicit domain matches, without wildcards, are
+   * considered.
+   */
+  [Throws]
+  boolean matches(URI uri, optional boolean explicit = false);
+
+  [Throws]
+  boolean matches(DOMString url, optional boolean explicit = false);
+
+  /**
+   * Returns true if any sub-pattern matches the given cookie.
+   */
+  boolean matchesCookie(Cookie cookie);
+
+  /**
+   * Returns true if any sub-pattern subsumes the given pattern.
+   */
+  boolean subsumes(MatchPattern pattern);
+
+  /**
+   * Returns true if any sub-pattern subsumes the given pattern,
+   * ignoring any of the schemes in the patterns.
+   */
+  boolean subsumesDomain(MatchPattern pattern);
+
+  /**
+   * Returns true if any sub-pattern overlaps the given pattern.
+   */
+  boolean overlaps(MatchPattern pattern);
+
+  /**
+   * Returns true if any sub-pattern overlaps any sub-pattern the given
+   * pattern set.
+   */
+  boolean overlaps(MatchPatternSet patternSet);
+
+  /**
+   * Returns true if any sub-pattern overlaps *every* sub-pattern in the given
+   * pattern set.
+   */
+  boolean overlapsAll(MatchPatternSet patternSet);
+
+  [Cached, Constant, Frozen]
+  readonly attribute sequence<MatchPattern> patterns;
+};
+
+dictionary MatchPatternOptions {
+  /**
+   * If true, the path portion of the pattern is ignored, and replaced with a
+   * wildcard. The `pattern` property is updated to reflect this.
+   */
+  boolean ignorePath = false;
+
+  /**
+   * If true, the set of schemes this pattern can match is restricted to
+   * those accessible by WebExtensions.
+   */
+  boolean restrictSchemes = true;
+};
diff --git a/dom/chrome-webidl/MediaController.webidl b/dom/chrome-webidl/MediaController.webidl
new file mode 100644
index 0000000000..b16282877a
--- /dev/null
+++ b/dom/chrome-webidl/MediaController.webidl
@@ -0,0 +1,75 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * This enum lists all supported behaviors on the media controller.
+ */
+enum MediaControlKey {
+  "focus",
+  "play",
+  "pause",
+  "playpause",
+  "previoustrack",
+  "nexttrack",
+  "seekbackward",
+  "seekforward",
+  "skipad",
+  "seekto",
+  "stop",
+};
+
+/**
+ * MediaController is used to control media playback for a tab, and each tab
+ * would only have one media controller, which can be accessed from the
+ * canonical browsing context.
+ */
+[Exposed=Window, ChromeOnly]
+interface MediaController : EventTarget {
+  readonly attribute unsigned long long id;
+  readonly attribute boolean isActive;
+  readonly attribute boolean isAudible;
+  readonly attribute boolean isPlaying;
+  readonly attribute MediaSessionPlaybackState playbackState;
+
+  [Throws]
+  MediaMetadataInit getMetadata();
+
+  [Frozen, Cached, Pure]
+  readonly attribute sequence<MediaControlKey> supportedKeys;
+
+  attribute EventHandler onactivated;
+  attribute EventHandler ondeactivated;
+
+  // Following events would only be dispatched after controller is active.
+  attribute EventHandler onmetadatachange;
+  attribute EventHandler onplaybackstatechange;
+  attribute EventHandler onpositionstatechange;
+  attribute EventHandler onsupportedkeyschange;
+
+  undefined focus();
+  undefined play();
+  undefined pause();
+  undefined stop();
+  undefined prevTrack();
+  undefined nextTrack();
+  undefined seekBackward();
+  undefined seekForward();
+  undefined skipAd();
+  undefined seekTo(double seekTime, optional boolean fastSeek = false);
+};
+
+[ChromeOnly,Exposed=Window,HeaderFile="mozilla/dom/MediaControlService.h"]
+namespace MediaControlService {
+  // This is used to generate fake media control keys event in testing.
+  undefined generateMediaControlKey(MediaControlKey aKey);
+
+  // This is used to get the media metadata from the current main controller in
+  // testing.
+  MediaMetadataInit getCurrentActiveMediaMetadata();
+
+  // This is used to get the actual media playback state from the current main
+  // controller in testing.
+  MediaSessionPlaybackState getCurrentMediaSessionPlaybackState();
+};
diff --git a/dom/chrome-webidl/MessageManager.webidl b/dom/chrome-webidl/MessageManager.webidl
new file mode 100644
index 0000000000..d77f1751ee
--- /dev/null
+++ b/dom/chrome-webidl/MessageManager.webidl
@@ -0,0 +1,576 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+interface nsIEventTarget;
+interface Principal;
+
+/**
+ * Message managers provide a way for chrome-privileged JS code to
+ * communicate with each other, even across process boundaries.
+ *
+ * Message managers are separated into "parent side" and "child side".
+ * These don't always correspond to process boundaries, but can.  For
+ * each child-side message manager, there is always exactly one
+ * corresponding parent-side message manager that it sends messages
+ * to.  However, for each parent-side message manager, there may be
+ * either one or many child-side managers it can message.
+ *
+ * Message managers that always have exactly one "other side" are of
+ * type MessageSender.  Parent-side message managers that have many
+ * "other sides" are of type MessageBroadcaster.
+ *
+ * Child-side message managers can send synchronous messages to their
+ * parent side, but not the other way around.
+ *
+ * There are two realms of message manager hierarchies.  One realm
+ * approximately corresponds to DOM elements, the other corresponds to
+ * process boundaries.
+ *
+ * Message managers corresponding to DOM elements
+ * ==============================================
+ *
+ * In this realm of message managers, there are
+ *  - "frame message managers" which correspond to frame elements
+ *  - "window message managers" which correspond to top-level chrome
+ *    windows
+ *  - "group message managers" which correspond to named message
+ *    managers with a specific window MM as the parent
+ *  - the "global message manager", on the parent side.  See below.
+ *
+ * The DOM-realm message managers can communicate in the ways shown by
+ * the following diagram.  The parent side and child side can
+ * correspond to process boundaries, but don't always.
+ *
+ *  Parent side                         Child side
+ * -------------                       ------------
+ *  global MMg
+ *   |
+ *   +-->window MMw1
+ *   |    |
+ *   |    +-->frame MMp1_1<------------>frame MMc1_1
+ *   |    |
+ *   |    +-->frame MMp1_2<------------>frame MMc1_2
+ *   |    |
+ *   |    +-->group MMgr1
+ *   |    |    |
+ *   |    |    +-->frame MMp2_1<------->frame MMc2_1
+ *   |    |    |
+ *   |    |    +-->frame MMp2_2<------->frame MMc2_2
+ *   |    |
+ *   |    +-->group MMgr2
+ *   |    |    ...
+ *   |    |
+ *   |    ...
+ *   |
+ *   +-->window MMw2
+ *   ...
+ *
+ * For example: a message sent from MMc1_1, from the child side, is
+ * sent only to MMp1_1 on the parent side.  However, note that all
+ * message managers in the hierarchy above MMp1_1, in this diagram
+ * MMw1 and MMg, will also notify their message listeners when the
+ * message arrives.
+ *
+ * A message sent from MMc2_1 will be sent to MMp2_1 and also notify
+ * all message managers in the hierarchy above that, including the
+ * group message manager MMgr1.
+
+ * For example: a message broadcast through the global MMg on the
+ * parent side would be broadcast to MMw1, which would transitively
+ * broadcast it to MMp1_1, MM1p_2.  The message would next be
+ * broadcast to MMgr1, which would broadcast it to MMp2_1 and MMp2_2.
+ * After that it would broadcast to MMgr2 and then to MMw2, and so
+ * on down the hierarchy.
+ *
+ *   ***** PERFORMANCE AND SECURITY WARNING *****
+ * Messages broadcast through the global MM and window or group MMs
+ * can result in messages being dispatched across many OS processes,
+ * and to many processes with different permissions.  Great care
+ * should be taken when broadcasting.
+ *
+ * Interfaces
+ * ----------
+ *
+ * The global MMg and window MMw's are message broadcasters implementing
+ * MessageBroadcaster while the frame MMp's are simple message senders (MessageSender).
+ * Their counterparts in the content processes are message senders implementing
+ * ContentFrameMessageManager.
+ *
+ *                 MessageListenerManager
+ *               /                        \
+ * MessageSender                            MessageBroadcaster
+ *       |
+ * SyncMessageSender (content process/in-process only)
+ *       |
+ * ContentFrameMessageManager (content process/in-process only)
+ *       |
+ * nsIInProcessContentFrameMessageManager (in-process only)
+ *
+ *
+ * Message managers in the chrome process also implement FrameScriptLoader.
+ *
+ *
+ * Message managers corresponding to process boundaries
+ * ====================================================
+ *
+ * The second realm of message managers is the "process message
+ * managers".  With one exception, these always correspond to process
+ * boundaries.  The picture looks like
+ *
+ *  Parent process                      Child processes
+ * ----------------                    -----------------
+ *  global (GPPMM)
+ *   |
+ *   +-->parent in-process PIPMM<-->child in-process CIPPMM
+ *   |
+ *   +-->parent (PPMM1)<------------------>child (CPMM1)
+ *   |
+ *   +-->parent (PPMM2)<------------------>child (CPMM2)
+ *   ...
+ *
+ * Note, PIPMM and CIPPMM both run in the parent process.
+ *
+ * For example: the parent-process PPMM1 sends messages to the
+ * child-process CPMM1.
+ *
+ * For example: CPMM1 sends messages directly to PPMM1. The global GPPMM
+ * will also notify their message listeners when the message arrives.
+ *
+ * For example: messages sent through the global GPPMM will be
+ * dispatched to the listeners of the same-process, CIPPMM, CPMM1,
+ * CPMM2, etc.
+ *
+ *   ***** PERFORMANCE AND SECURITY WARNING *****
+ * Messages broadcast through the GPPMM can result in messages
+ * being dispatched across many OS processes, and to many processes
+ * with different permissions.  Great care should be taken when
+ * broadcasting.
+ *
+ * Requests sent to parent-process message listeners should usually
+ * have replies scoped to the requesting CPMM.  The following pattern
+ * is common
+ *
+ *  const ParentProcessListener = {
+ *    receiveMessage: function(aMessage) {
+ *      switch (aMessage.name) {
+ *      case "Foo:Request":
+ *        // service request
+ *        aMessage.target.sendAsyncMessage("Foo:Response", { data });
+ *      }
+ *    }
+ *  };
+ */
+
+dictionary ReceiveMessageArgument
+{
+  /**
+   * The target of the message. Either an element owning the message manager, or message
+   * manager itself if no element owns it.
+   */
+  required nsISupports target;
+
+  /**
+   * Message name.
+   */
+  required DOMString name;
+
+  required boolean sync;
+
+  /**
+   * Structured clone of the sent message data
+   */
+  any data = null;
+
+  /**
+   * Same as .data, deprecated.
+   */
+  any json = null;
+
+  sequence<MessagePort> ports;
+
+  FrameLoader targetFrameLoader;
+};
+
+[Exposed=Window]
+callback interface MessageListener
+{
+  /**
+   * Each listener is invoked with its own copy of the message
+   * parameter.
+   *
+   * When the listener is called, 'this' value is the target of the message.
+   *
+   * If the message is synchronous, the possible return value is
+   * returned as JSON (will be changed to use structured clones).
+   * When there are multiple listeners to sync messages, each
+   * listener's return value is sent back as an array.  |undefined|
+   * return values show up as undefined values in the array.
+   */
+  any receiveMessage(ReceiveMessageArgument argument);
+};
+
+[ChromeOnly, Exposed=Window]
+interface MessageListenerManager
+{
+  // All the methods are pulled in via mixin.
+};
+MessageListenerManager includes MessageListenerManagerMixin;
+
+interface mixin MessageListenerManagerMixin
+{
+  /**
+   * Register |listener| to receive |messageName|.  All listener
+   * callbacks for a particular message are invoked when that message
+   * is received.
+   *
+   * The message manager holds a strong ref to |listener|.
+   *
+   * If the same listener registers twice for the same message, the
+   * second registration is ignored.
+   *
+   * Pass true for listenWhenClosed if you want to receive messages
+   * during the short period after a frame has been removed from the
+   * DOM and before its frame script has finished unloading. This
+   * parameter only has an effect for frame message managers in
+   * the main process. Default is false.
+   */
+  [Throws]
+  undefined addMessageListener(DOMString messageName,
+                               MessageListener listener,
+                               optional boolean listenWhenClosed = false);
+
+  /**
+   * Undo an |addMessageListener| call -- that is, calling this causes us to no
+   * longer invoke |listener| when |messageName| is received.
+   *
+   * removeMessageListener does not remove a message listener added via
+   * addWeakMessageListener; use removeWeakMessageListener for that.
+   */
+  [Throws]
+  undefined removeMessageListener(DOMString messageName,
+                                  MessageListener listener);
+
+  /**
+   * This is just like addMessageListener, except the message manager holds a
+   * weak ref to |listener|.
+   *
+   * If you have two weak message listeners for the same message, they may be
+   * called in any order.
+   */
+  [Throws]
+  undefined addWeakMessageListener(DOMString messageName,
+                                   MessageListener listener);
+
+  /**
+   * This undoes an |addWeakMessageListener| call.
+   */
+  [Throws]
+  undefined removeWeakMessageListener(DOMString messageName,
+                                      MessageListener listener);
+};
+
+/**
+ * Message "senders" have a single "other side" to which messages are
+ * sent.  For example, a child-process message manager will send
+ * messages that are only delivered to its one parent-process message
+ * manager.
+ */
+[ChromeOnly, Exposed=Window]
+interface MessageSender : MessageListenerManager
+{
+  // All the methods are pulled in via mixin.
+};
+MessageSender includes MessageSenderMixin;
+
+/**
+ * Anyone including this MUST also incude MessageListenerManagerMixin.
+ */
+interface mixin MessageSenderMixin {
+  /**
+   * Send |messageName| and |obj| to the "other side" of this message
+   * manager.  This invokes listeners who registered for
+   * |messageName|.
+   *
+   * See ReceiveMessageArgument for the format of the data delivered to listeners.
+   * @throws NS_ERROR_NOT_INITIALIZED if the sender is not initialized.  For
+   *         example, we will throw NS_ERROR_NOT_INITIALIZED if we try to send
+   *         a message to a cross-process frame but the other process has not
+   *         yet been set up.
+   * @throws NS_ERROR_FAILURE when the message receiver cannot be found.  For
+   *         example, we will throw NS_ERROR_FAILURE if we try to send a message
+   *         to a cross-process frame whose process has crashed.
+   */
+  [Throws]
+  undefined sendAsyncMessage(optional DOMString? messageName = null,
+                             optional any obj,
+                             optional any transfers);
+
+  /**
+   * For remote browsers there is always a corresponding process message
+   * manager. The intention of this attribute is to link leaf level frame
+   * message managers on the parent side with the corresponding process
+   * message managers (if there is one). For any other cases this property
+   * is null.
+   */
+  [Throws]
+  readonly attribute MessageSender? processMessageManager;
+
+  /**
+   * For remote browsers, this contains the remoteType of the content child.
+   * Otherwise, it is empty.
+   */
+  [Throws]
+  readonly attribute UTF8String remoteType;
+};
+
+[ChromeOnly, Exposed=Window]
+interface SyncMessageSender : MessageSender
+{
+  // All the methods are pulled in via mixin.
+};
+SyncMessageSender includes SyncMessageSenderMixin;
+
+/**
+ * Anyone including this MUST also incude MessageSenderMixin.
+ */
+interface mixin SyncMessageSenderMixin
+{
+  /**
+   * Like |sendAsyncMessage()|, except blocks the sender until all
+   * listeners of the message have been invoked.  Returns an array
+   * containing return values from each listener invoked.
+   */
+  [Throws]
+  sequence<any> sendSyncMessage(optional DOMString? messageName = null,
+                                optional any obj);
+};
+
+/**
+ * ChildProcessMessageManager is used in a child process to communicate with the parent
+ * process.
+ */
+[ChromeOnly, Exposed=Window]
+interface ChildProcessMessageManager : SyncMessageSender
+{
+};
+
+/**
+ * Mixin for message manager globals.  Anyone including this MUST also
+ * include SyncMessageSenderMixin.
+ */
+interface mixin MessageManagerGlobal
+{
+  /**
+   * Print a string to stdout.
+   */
+  undefined dump(DOMString str);
+
+  /**
+   * Ascii base64 data to binary data and vice versa
+   */
+  [Throws]
+  DOMString atob(DOMString asciiString);
+  [Throws]
+  DOMString btoa(DOMString base64Data);
+};
+
+interface mixin FrameScriptLoader
+{
+  /**
+   * Load a script in the (remote) frame. |url| must be the absolute URL.
+   * data: URLs are also supported. For example data:,dump("foo\n");
+   * If allowDelayedLoad is true, script will be loaded when the
+   * remote frame becomes available. Otherwise the script will be loaded
+   * only if the frame is already available.
+   */
+  [Throws]
+  undefined loadFrameScript(DOMString url, boolean allowDelayedLoad,
+                            optional boolean runInGlobalScope = false);
+
+  /**
+   * Removes |url| from the list of scripts which support delayed load.
+   */
+  undefined removeDelayedFrameScript(DOMString url);
+
+  /**
+   * Returns all delayed scripts that will be loaded once a (remote)
+   * frame becomes available. The return value is a list of pairs
+   * [<URL>, <WasLoadedInGlobalScope>].
+   */
+  [Throws]
+  sequence<sequence<any>> getDelayedFrameScripts();
+};
+
+interface mixin ProcessScriptLoader
+{
+  /**
+   * Load a script in the (possibly remote) process. |url| must be the absolute
+   * URL. data: URLs are also supported. For example data:,dump("foo\n");
+   * If allowDelayedLoad is true, script will be loaded when the
+   * remote frame becomes available. Otherwise the script will be loaded
+   * only if the frame is already available.
+   */
+  [Throws]
+  undefined loadProcessScript(DOMString url, boolean allowDelayedLoad);
+
+  /**
+   * Removes |url| from the list of scripts which support delayed load.
+   */
+  undefined removeDelayedProcessScript(DOMString url);
+
+  /**
+   * Returns all delayed scripts that will be loaded once a (remote)
+   * frame becomes available. The return value is a list of pairs
+   * [<URL>, <WasLoadedInGlobalScope>].
+   */
+  [Throws]
+  sequence<sequence<any>> getDelayedProcessScripts();
+};
+
+/**
+ * Anyone including GlobalProcessScriptLoader MUST also include ProcessScriptLoader.
+ */
+interface mixin GlobalProcessScriptLoader
+{
+  /**
+   * Allows the parent process to set the initial process data for
+   * new, not-yet-created child processes. This attribute should only
+   * be used by the global parent process message manager. When a new
+   * process is created, it gets a copy of this data (via structured
+   * cloning). It can access the data via the initialProcessData
+   * attribute of its childprocessmessagemanager.
+   *
+   * This value will always be a JS object if it's not null or undefined. Different
+   * users are expected to set properties on this object. The property name should be
+   * unique enough that other Gecko consumers won't accidentally choose it.
+   */
+  [Throws]
+  readonly attribute any initialProcessData;
+
+  readonly attribute MozWritableSharedMap sharedData;
+};
+
+[ChromeOnly, Exposed=Window]
+interface ContentFrameMessageManager : EventTarget
+{
+  /**
+   * The current top level window in the frame or null.
+   */
+  [Throws]
+  readonly attribute WindowProxy? content;
+
+  /**
+   * The top level docshell or null.
+   */
+  [Throws]
+  readonly attribute nsIDocShell? docShell;
+
+  /**
+   * Returns the SchedulerEventTarget corresponding to the TabGroup
+   * for this frame.
+   */
+  readonly attribute nsIEventTarget? tabEventTarget;
+
+};
+ContentFrameMessageManager includes MessageManagerGlobal;
+ContentFrameMessageManager includes SyncMessageSenderMixin;
+ContentFrameMessageManager includes MessageSenderMixin;
+ContentFrameMessageManager includes MessageListenerManagerMixin;
+
+[ChromeOnly, Exposed=Window]
+interface ContentProcessMessageManager
+{
+  /**
+   * Read out a copy of the object that was initialized in the parent
+   * process via ProcessScriptLoader.initialProcessData.
+   */
+  [Throws]
+  readonly attribute any initialProcessData;
+
+  readonly attribute MozSharedMap? sharedData;
+};
+ContentProcessMessageManager includes MessageManagerGlobal;
+ContentProcessMessageManager includes SyncMessageSenderMixin;
+ContentProcessMessageManager includes MessageSenderMixin;
+ContentProcessMessageManager includes MessageListenerManagerMixin;
+
+/**
+ * Message "broadcasters" don't have a single "other side" that they send messages to, but
+ * rather a set of subordinate message managers. For example, broadcasting a message
+ * through a window message manager will broadcast the message to all frame message
+ * managers within its window.
+ */
+[ChromeOnly, Exposed=Window]
+interface MessageBroadcaster : MessageListenerManager
+{
+  /**
+   * Like |sendAsyncMessage()|, but also broadcasts this message to
+   * all "child" message managers of this message manager.  See long
+   * comment above for details.
+   *
+   * WARNING: broadcasting messages can be very expensive and leak
+   * sensitive data.  Use with extreme caution.
+   */
+  [Throws]
+  undefined broadcastAsyncMessage(optional DOMString? messageName = null,
+                                  optional any obj);
+
+  /**
+   * Number of subordinate message managers.
+   */
+  readonly attribute unsigned long childCount;
+
+  /**
+   * Return a single subordinate message manager.
+   */
+  MessageListenerManager? getChildAt(unsigned long aIndex);
+
+  /**
+   * Some processes are kept alive after their last tab/window are closed for testing
+   * (see dom.ipc.keepProcessesAlive). This function releases those.
+   */
+   undefined releaseCachedProcesses();
+};
+
+/**
+ * ChromeMessageBroadcaster is used for window and group message managers.
+ */
+[ChromeOnly, Exposed=Window]
+interface ChromeMessageBroadcaster : MessageBroadcaster
+{
+};
+ChromeMessageBroadcaster includes FrameScriptLoader;
+
+/**
+ * ParentProcessMessageManager is used in a parent process to communicate with all the
+ * child processes.
+ */
+[ChromeOnly, Exposed=Window]
+interface ParentProcessMessageManager : MessageBroadcaster
+{
+};
+ParentProcessMessageManager includes ProcessScriptLoader;
+ParentProcessMessageManager includes GlobalProcessScriptLoader;
+
+[ChromeOnly, Exposed=Window]
+interface ChromeMessageSender : MessageSender
+{
+};
+ChromeMessageSender includes FrameScriptLoader;
+
+/**
+ * ProcessMessageManager is used in a parent process to communicate with a child process
+ * (or with the process itself in a single-process scenario).
+ */
+[ChromeOnly, Exposed=Window]
+interface ProcessMessageManager : MessageSender
+{
+  // PID of the process being communicated with.
+  readonly attribute long osPid;
+
+  // Whether this is message manager for the current process.
+  readonly attribute boolean isInProcess;
+};
+ProcessMessageManager includes ProcessScriptLoader;
diff --git a/dom/chrome-webidl/MozDocumentObserver.webidl b/dom/chrome-webidl/MozDocumentObserver.webidl
new file mode 100644
index 0000000000..06abd37eeb
--- /dev/null
+++ b/dom/chrome-webidl/MozDocumentObserver.webidl
@@ -0,0 +1,20 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+[Exposed=Window]
+callback interface MozDocumentCallback {
+  undefined onNewDocument(MozDocumentMatcher matcher, WindowProxy window);
+  undefined onPreloadDocument(MozDocumentMatcher matcher, LoadInfo loadInfo);
+};
+
+[ChromeOnly, Exposed=Window]
+interface MozDocumentObserver {
+  constructor(MozDocumentCallback callbacks);
+
+  [Throws]
+  undefined observe(sequence<MozDocumentMatcher> matchers);
+  undefined disconnect();
+};
diff --git a/dom/chrome-webidl/MozSharedMap.webidl b/dom/chrome-webidl/MozSharedMap.webidl
new file mode 100644
index 0000000000..ef262fc48e
--- /dev/null
+++ b/dom/chrome-webidl/MozSharedMap.webidl
@@ -0,0 +1,54 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+typedef any StructuredClonable;
+
+[ChromeOnly, Exposed=Window]
+interface MozSharedMapChangeEvent : Event {
+  [Cached, Constant]
+  readonly attribute sequence<DOMString> changedKeys;
+};
+
+dictionary MozSharedMapChangeEventInit : EventInit {
+  required sequence<DOMString> changedKeys;
+};
+
+[ChromeOnly, Exposed=Window]
+interface MozSharedMap : EventTarget {
+  boolean has(DOMString name);
+
+  [Throws]
+  StructuredClonable get(DOMString name);
+
+  iterable<DOMString, StructuredClonable>;
+};
+
+[ChromeOnly, Exposed=Window]
+interface MozWritableSharedMap : MozSharedMap {
+  /**
+   * Sets the given key to the given structured-clonable value. The value is
+   * synchronously structured cloned, and the serialized value is saved in the
+   * map.
+   *
+   * Unless flush() is called, the new value will be broadcast to content
+   * processes after a short delay.
+   */
+  [Throws]
+  undefined set(DOMString name, StructuredClonable value);
+
+  /**
+   * Removes the given key from the map.
+   *
+   * Unless flush() is called, the removal will be broadcast to content
+   * processes after a short delay.
+   */
+  undefined delete(DOMString name);
+
+  /**
+   * Broadcasts any pending changes to all content processes.
+   */
+  undefined flush();
+};
diff --git a/dom/chrome-webidl/MozStorageAsyncStatementParams.webidl b/dom/chrome-webidl/MozStorageAsyncStatementParams.webidl
new file mode 100644
index 0000000000..853d86581a
--- /dev/null
+++ b/dom/chrome-webidl/MozStorageAsyncStatementParams.webidl
@@ -0,0 +1,22 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+[ChromeOnly, Exposed=Window]
+interface MozStorageAsyncStatementParams
+{
+  readonly attribute unsigned long length;
+
+  [Throws]
+  getter any(unsigned long index);
+
+  [Throws]
+  getter any(DOMString name);
+
+  [Throws]
+  setter undefined(unsigned long index, any arg);
+
+  [Throws]
+  setter undefined(DOMString name, any arg);
+};
diff --git a/dom/chrome-webidl/MozStorageStatementParams.webidl b/dom/chrome-webidl/MozStorageStatementParams.webidl
new file mode 100644
index 0000000000..1c4eb4cbf7
--- /dev/null
+++ b/dom/chrome-webidl/MozStorageStatementParams.webidl
@@ -0,0 +1,22 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+[ChromeOnly, Exposed=Window]
+interface MozStorageStatementParams
+{
+  readonly attribute unsigned long length;
+
+  [Throws]
+  getter any(unsigned long index);
+
+  [Throws]
+  getter any(DOMString name);
+
+  [Throws]
+  setter undefined(unsigned long index, any arg);
+
+  [Throws]
+  setter undefined(DOMString name, any arg);
+};
diff --git a/dom/chrome-webidl/MozStorageStatementRow.webidl b/dom/chrome-webidl/MozStorageStatementRow.webidl
new file mode 100644
index 0000000000..2ba31f5810
--- /dev/null
+++ b/dom/chrome-webidl/MozStorageStatementRow.webidl
@@ -0,0 +1,11 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+[ChromeOnly, Exposed=Window]
+interface MozStorageStatementRow
+{
+  [Throws]
+  getter any(DOMString name);
+};
diff --git a/dom/chrome-webidl/NetDashboard.webidl b/dom/chrome-webidl/NetDashboard.webidl
new file mode 100644
index 0000000000..937ffc11d8
--- /dev/null
+++ b/dom/chrome-webidl/NetDashboard.webidl
@@ -0,0 +1,155 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file defines dictionaries used by about:networking page.
+
+dictionary SocketElement {
+  DOMString host = "";
+  unsigned long port = 0;
+  boolean active = false;
+  DOMString type = "";
+  double sent = 0;
+  double received = 0;
+};
+
+[GenerateConversionToJS]
+dictionary SocketsDict {
+  sequence<SocketElement> sockets;
+  double sent = 0;
+  double received = 0;
+};
+
+dictionary HttpConnInfo {
+  unsigned long rtt = 0;
+  unsigned long ttl = 0;
+  DOMString protocolVersion = "";
+};
+
+dictionary DnsAndSockInfoDict {
+  boolean speculative = false;
+};
+
+dictionary HttpConnectionElement {
+  DOMString host = "";
+  unsigned long port = 0;
+  DOMString httpVersion = "";
+  boolean ssl = false;
+  sequence<HttpConnInfo> active;
+  sequence<HttpConnInfo> idle;
+  sequence<DnsAndSockInfoDict> dnsAndSocks;
+};
+
+[GenerateConversionToJS]
+dictionary HttpConnDict {
+  sequence<HttpConnectionElement> connections;
+};
+
+dictionary WebSocketElement {
+  DOMString hostport = "";
+  unsigned long msgsent = 0;
+  unsigned long msgreceived = 0;
+  double sentsize = 0;
+  double receivedsize = 0;
+  boolean encrypted = false;
+};
+
+[GenerateConversionToJS]
+dictionary WebSocketDict {
+  sequence<WebSocketElement> websockets;
+};
+
+dictionary DnsCacheEntry {
+  DOMString hostname = "";
+  sequence<DOMString> hostaddr;
+  DOMString family = "";
+  double expiration = 0;
+  boolean trr = false;
+  DOMString originAttributesSuffix = "";
+  DOMString flags = "";
+};
+
+[GenerateConversionToJS]
+dictionary DNSCacheDict {
+  sequence<DnsCacheEntry> entries;
+};
+
+[GenerateConversionToJS]
+dictionary DNSLookupDict {
+  sequence<DOMString> address;
+  DOMString error = "";
+  boolean answer = false;
+};
+
+dictionary SVCParam {
+  unsigned short type = 0;
+};
+
+dictionary SVCParamAlpn : SVCParam {
+  DOMString alpn = "";
+};
+
+dictionary SVCParamNoDefaultAlpn : SVCParam {
+};
+
+dictionary SVCParamPort : SVCParam {
+  unsigned short port = 0;
+};
+
+dictionary SVCParamIPv4Hint : SVCParam {
+  sequence<DOMString> address;
+};
+
+dictionary SVCParamIPv6Hint : SVCParam {
+  sequence<DOMString> address;
+};
+
+dictionary SVCParamEchConfig : SVCParam {
+  DOMString echConfig = "";
+};
+
+dictionary SVCParamODoHConfig : SVCParam {
+  DOMString ODoHConfig = "";
+};
+
+dictionary HTTPSRecord {
+  unsigned short priority = 0;
+  DOMString targetName = "";
+  SVCParamAlpn alpn;
+  SVCParamNoDefaultAlpn noDefaultAlpn;
+  SVCParamPort port;
+  SVCParamIPv4Hint ipv4Hint;
+  SVCParamIPv6Hint ipv6Hint;
+  SVCParamEchConfig echConfig;
+  SVCParamODoHConfig ODoHConfig;
+};
+
+[GenerateConversionToJS]
+dictionary HTTPSRRLookupDict {
+  DOMString error = "";
+  boolean answer = false;
+  sequence<HTTPSRecord> records;
+};
+
+[GenerateConversionToJS]
+dictionary ConnStatusDict {
+  DOMString status = "";
+};
+
+dictionary RcwnPerfStats {
+  unsigned long avgShort = 0;
+  unsigned long avgLong = 0;
+  unsigned long stddevLong = 0;
+};
+
+[GenerateConversionToJS]
+dictionary RcwnStatus {
+  unsigned long totalNetworkRequests = 0;
+  unsigned long rcwnCacheWonCount = 0;
+  unsigned long rcwnNetWonCount = 0;
+  unsigned long cacheSlowCount = 0;
+  unsigned long cacheNotSlowCount = 0;
+  // Sequence is indexed by CachePerfStats::EDataType
+  sequence<RcwnPerfStats> perfStats;
+};
diff --git a/dom/chrome-webidl/PathUtils.webidl b/dom/chrome-webidl/PathUtils.webidl
new file mode 100644
index 0000000000..0b8be50f0b
--- /dev/null
+++ b/dom/chrome-webidl/PathUtils.webidl
@@ -0,0 +1,187 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * PathUtils is a set of utilities for operating on absolute paths.
+ */
+[ChromeOnly, Exposed=(Window, Worker)]
+namespace PathUtils {
+  /**
+   * Return the last path component.
+   *
+   * @param path An absolute path.
+   *
+   * @returns The last path component.
+   */
+  [Throws]
+  DOMString filename(DOMString path);
+
+  /**
+   * Return an ancestor directory of the given path.
+   *
+   * @param path An absolute path.
+   * @param depth The number of ancestors to remove, defaulting to 1 (i.e., the
+   *              parent).
+   *
+   * @return The ancestor directory.
+   *
+   *         If the path provided is a root path (e.g., `C:` on Windows or `/`
+   *         on *NIX), then null is returned.
+   */
+  [Throws]
+  DOMString? parent(DOMString path, optional long depth = 1);
+
+  /**
+   * Join the given components into a full path.
+   *
+   * @param components The path components. The first component must be an
+   *                   absolute path. There must be at least one component.
+   */
+  [Throws]
+  DOMString join(DOMString... components);
+
+  /**
+   * Join the given relative path to the base path.
+   *
+   * @param base The base path. This must be an absolute path.
+   * @param relativePath A relative path to join to the base path.
+   */
+  [Throws]
+  DOMString joinRelative(DOMString base, DOMString relativePath);
+
+  /**
+   * Creates an adjusted path using a path whose length is already close
+   * to MAX_PATH. For windows only.
+   *
+   * @param path An absolute path.
+   */
+  [Throws]
+  DOMString toExtendedWindowsPath(DOMString path);
+
+  /**
+   * Normalize a path by removing multiple separators and `..` and `.`
+   * directories.
+   *
+   * On UNIX platforms, the path must exist as symbolic links will be resolved.
+   *
+   * @param path The absolute path to normalize.
+   *
+   */
+  [Throws]
+  DOMString normalize(DOMString path);
+
+  /**
+   * Split a path into its components.
+   *
+   * @param path An absolute path.
+   */
+  [Throws]
+  sequence<DOMString> split(DOMString path);
+
+  /**
+   * Split a relative path into its components.
+   *
+   * @param path A relative path.
+   */
+  [Throws]
+  sequence<DOMString> splitRelative(DOMString path, optional SplitRelativeOptions options = {});
+
+  /**
+   * Transform a file path into a file: URI
+   *
+   * @param path An absolute path.
+   *
+   * @return The file: URI as a string.
+   */
+  [Throws]
+  UTF8String toFileURI(DOMString path);
+
+  /**
+   * Determine if the given path is an absolute or relative path.
+   *
+   * @param path A file path that is either relative or absolute.
+   *
+   * @return Whether or not the path is absolute.
+   */
+  boolean isAbsolute(DOMString path);
+};
+
+[Exposed=Window]
+partial namespace PathUtils {
+  /**
+   * The profile directory.
+   */
+  [Throws, BinaryName="ProfileDirSync"]
+  readonly attribute DOMString profileDir;
+
+  /**
+   * The local-specific profile directory.
+   */
+  [Throws, BinaryName="LocalProfileDirSync"]
+  readonly attribute DOMString localProfileDir;
+
+  /**
+   * The temporary directory for the process.
+   */
+  [Throws, BinaryName="TempDirSync"]
+  readonly attribute DOMString tempDir;
+
+  /**
+   * The OS temporary directory.
+   */
+  [Throws, BinaryName="OSTempDirSync"]
+  readonly attribute DOMString osTempDir;
+
+  /**
+   * The libxul path.
+   */
+  [Throws, BinaryName="XulLibraryPathSync"]
+  readonly attribute DOMString xulLibraryPath;
+};
+
+[Exposed=Worker]
+partial namespace PathUtils {
+  /**
+   * The profile directory.
+   */
+  [NewObject, BinaryName="GetProfileDirAsync"]
+  Promise<DOMString> getProfileDir();
+
+  /**
+   * The local-specific profile directory.
+   */
+  [NewObject, BinaryName="GetLocalProfileDirAsync"]
+  Promise<DOMString> getLocalProfileDir();
+
+  /**
+   * The temporary directory for the process.
+   */
+  [NewObject, BinaryName="GetTempDirAsync"]
+  Promise<DOMString> getTempDir();
+
+  /**
+   * The OS temporary directory.
+   */
+  [NewObject, BinaryName="GetOSTempDirAsync"]
+  Promise<DOMString> getOSTempDir();
+
+  /**
+   * The libxul path.
+   */
+  [NewObject, BinaryName="GetXulLibraryPathAsync"]
+  Promise<DOMString> getXulLibraryPath();
+};
+
+dictionary SplitRelativeOptions {
+  /** Allow for a path that contains empty components. */
+  boolean allowEmpty = false;
+
+  /** Allow for a path that contains ".." components. */
+  boolean allowParentDir = false;
+
+  /** Allow for a path that contains "." components. */
+  boolean allowCurrentDir = false;
+};
diff --git a/dom/chrome-webidl/PlacesEvent.webidl b/dom/chrome-webidl/PlacesEvent.webidl
new file mode 100644
index 0000000000..63d89572d8
--- /dev/null
+++ b/dom/chrome-webidl/PlacesEvent.webidl
@@ -0,0 +1,520 @@
+enum PlacesEventType {
+  "none",
+
+  /**
+   * data: PlacesVisit. Fired whenever a page is visited.
+   */
+  "page-visited",
+  /**
+   * data: PlacesBookmarkAddition. Fired whenever a bookmark
+   * (or a bookmark folder/separator) is created.
+   */
+  "bookmark-added",
+  /**
+   * data: PlacesBookmarkRemoved. Fired whenever a bookmark
+   * (or a bookmark folder/separator) is removed.
+   */
+  "bookmark-removed",
+  /**
+   * data: PlacesBookmarkMoved. Fired whenever a bookmark
+   * (or a bookmark folder/separator) is moved.
+   */
+  "bookmark-moved",
+  /**
+   * data: PlacesBookmarkGuid. Fired whenever a bookmark guid changes.
+   */
+  "bookmark-guid-changed",
+  /**
+   * data: PlacesBookmarkTags. Fired whenever tags of bookmark changes.
+   */
+  "bookmark-tags-changed",
+  /**
+   * data: PlacesBookmarkTime.
+   * Fired whenever dateAdded or lastModified of a bookmark is explicitly changed
+   * through the Bookmarks API. This notification doesn't fire when a bookmark is
+   * created, or when a property of a bookmark (e.g. title) is changed, even if
+   * lastModified will be updated as a consequence of that change.
+   */
+  "bookmark-time-changed",
+  /**
+   * data: PlacesBookmarkTitle. Fired whenever a bookmark title changes.
+   */
+  "bookmark-title-changed",
+  /**
+   * data: PlacesBookmarkUrl. Fired whenever a bookmark url changes.
+   */
+  "bookmark-url-changed",
+  /**
+   * data: PlacesFavicon. Fired whenever a favicon changes.
+   */
+  "favicon-changed",
+  /**
+   * data: PlacesVisitTitle. Fired whenever a page title changes.
+   */
+  "page-title-changed",
+  /**
+   * data: PlacesHistoryCleared. Fired whenever history is cleared.
+   */
+  "history-cleared",
+  /**
+   * data: PlacesRanking. Fired whenever pages ranking is changed.
+   */
+  "pages-rank-changed",
+  /**
+   * data: PlacesVisitRemoved. Fired whenever a page or its visits are removed.
+   * This may be invoked when a page is removed from the store because it has no more
+   * visits, nor bookmarks. It may also be invoked when all or some of the page visits are
+   * removed, but the page itself is not removed from the store, because it may be
+   * bookmarked.
+   */
+  "page-removed",
+  /**
+   * data: PlacesPurgeCaches. Fired whenever changes happened that could not be observed
+   * through other notifications, for example a database fixup. When received, observers,
+   * especially data views, should drop any caches and reload from scratch.
+   */
+  "purge-caches",
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesEvent {
+  readonly attribute PlacesEventType type;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesVisit : PlacesEvent {
+  /**
+   * URL of the visit.
+   */
+  readonly attribute DOMString url;
+
+  /**
+   * Id of the visit.
+   */
+  readonly attribute unsigned long long visitId;
+
+  /**
+   * Time of the visit, in milliseconds since epoch.
+   */
+  readonly attribute unsigned long long visitTime;
+
+  /**
+   * The id of the visit the user came from, defaults to 0 for no referrer.
+   */
+  readonly attribute unsigned long long referringVisitId;
+
+  /**
+   * One of nsINavHistory.TRANSITION_*
+   */
+  readonly attribute unsigned long transitionType;
+
+  /**
+   * The unique id associated with the page.
+   */
+  readonly attribute ByteString pageGuid;
+
+  /**
+   * Whether the visited page is marked as hidden.
+   */
+  readonly attribute boolean hidden;
+
+  /**
+   * Number of visits (including this one) for this URL.
+   */
+  readonly attribute unsigned long visitCount;
+
+  /**
+   * Whether the URL has been typed or not.
+   * TODO (Bug 1271801): This will become a count, rather than a boolean.
+   * For future compatibility, always compare it with "> 0".
+   */
+  readonly attribute unsigned long typedCount;
+
+  /**
+   * The last known title of the page. Might not be from the current visit,
+   * and might be null if it is not known.
+   */
+  readonly attribute DOMString? lastKnownTitle;
+};
+
+/**
+ * Base class for properties that are common to all bookmark events.
+ */
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmark : PlacesEvent {
+  /**
+   * The id of the item.
+   */
+  readonly attribute long long id;
+
+  /**
+   * The id of the folder to which the item belongs.
+   */
+  readonly attribute long long parentId;
+
+  /**
+   * The type of the added item (see TYPE_* constants in nsINavBooksService.idl).
+   */
+  readonly attribute unsigned short itemType;
+
+  /**
+   * The URI of the added item if it was TYPE_BOOKMARK, "" otherwise.
+   */
+  readonly attribute DOMString url;
+
+  /**
+   * The unique ID associated with the item.
+   */
+  readonly attribute ByteString guid;
+
+  /**
+   * The unique ID associated with the item's parent.
+   */
+  readonly attribute ByteString parentGuid;
+
+  /**
+   * A change source constant from nsINavBookmarksService::SOURCE_*,
+   * passed to the method that notifies the observer.
+   */
+  readonly attribute unsigned short source;
+
+  /**
+   * True if the item is a tag or a tag folder.
+   * NOTE: this will go away with bug 424160.
+   */
+  readonly attribute boolean isTagging;
+};
+
+dictionary PlacesBookmarkAdditionInit {
+  required long long id;
+  required long long parentId;
+  required unsigned short itemType;
+  required DOMString url;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required unsigned short source;
+  required long index;
+  required DOMString title;
+  required unsigned long long dateAdded;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkAddition : PlacesBookmark {
+  constructor(PlacesBookmarkAdditionInit initDict);
+
+  /**
+   * The item's index in the folder.
+   */
+  readonly attribute long index;
+
+  /**
+   * The title of the added item.
+   */
+  readonly attribute DOMString title;
+
+  /**
+   * The time that the item was added, in milliseconds from the epoch.
+   */
+  readonly attribute unsigned long long dateAdded;
+};
+
+dictionary PlacesBookmarkRemovedInit {
+  required long long id;
+  required long long parentId;
+  required unsigned short itemType;
+  required DOMString url;
+  required DOMString title;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required unsigned short source;
+  required long index;
+  required boolean isTagging;
+  boolean isDescendantRemoval = false;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkRemoved : PlacesBookmark {
+  constructor(PlacesBookmarkRemovedInit initDict);
+  /**
+   * The item's index in the folder.
+   */
+  readonly attribute long index;
+
+  /**
+   * The title of the the removed item.
+   */
+  readonly attribute DOMString title;
+
+  /**
+   * The item is a descendant of an item whose notification has been sent out.
+   */
+  readonly attribute boolean isDescendantRemoval;
+};
+
+dictionary PlacesBookmarkMovedInit {
+  required long long id;
+  required unsigned short itemType;
+  DOMString? url = null;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required long index;
+  required ByteString oldParentGuid;
+  required long oldIndex;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+/**
+ * NOTE: Though PlacesBookmarkMoved extends PlacesBookmark,
+ *       parentId will not be set. Use parentGuid instead.
+ */
+interface PlacesBookmarkMoved : PlacesBookmark {
+  constructor(PlacesBookmarkMovedInit initDict);
+  /**
+   * The item's index in the folder.
+   */
+  readonly attribute long index;
+
+  /**
+   * The unique ID associated with the item's old parent.
+   */
+  readonly attribute ByteString oldParentGuid;
+
+  /**
+   * The item's old index in the folder.
+   */
+  readonly attribute long oldIndex;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkChanged : PlacesBookmark {
+  /**
+   * The updated last modified value in milliseconds.
+   */
+  readonly attribute long long lastModified;
+};
+
+dictionary PlacesBookmarkGuidInit {
+  required long long id;
+  required unsigned short itemType;
+  DOMString? url = null;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required long long lastModified;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkGuid : PlacesBookmarkChanged {
+  constructor(PlacesBookmarkGuidInit initDict);
+};
+
+dictionary PlacesBookmarkTagsInit {
+  required long long id;
+  required unsigned short itemType;
+  DOMString? url = null;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required sequence<DOMString> tags;
+  required long long lastModified;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkTags : PlacesBookmarkChanged {
+  constructor(PlacesBookmarkTagsInit initDict);
+
+  /**
+   * Tags the bookmark has currently.
+   */
+  [Constant,Cached]
+  readonly attribute sequence<DOMString> tags;
+};
+
+dictionary PlacesBookmarkTimeInit {
+  required long long id;
+  required unsigned short itemType;
+  DOMString? url = null;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required long long dateAdded;
+  required long long lastModified;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkTime : PlacesBookmarkChanged {
+  constructor(PlacesBookmarkTimeInit initDict);
+
+  /**
+   * The added date in milliseconds.
+   */
+  readonly attribute long long dateAdded;
+};
+
+dictionary PlacesBookmarkTitleInit {
+  required long long id;
+  required unsigned short itemType;
+  DOMString? url = null;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required DOMString title;
+  required long long lastModified;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkTitle : PlacesBookmarkChanged {
+  constructor(PlacesBookmarkTitleInit initDict);
+
+  /**
+   * The title of the changed bookmark.
+   */
+  readonly attribute DOMString title;
+};
+
+dictionary PlacesBookmarkUrlInit {
+  required long long id;
+  required unsigned short itemType;
+  required DOMString url;
+  required ByteString guid;
+  required ByteString parentGuid;
+  required long long lastModified;
+  required unsigned short source;
+  required boolean isTagging;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesBookmarkUrl : PlacesBookmarkChanged {
+  constructor(PlacesBookmarkUrlInit initDict);
+};
+
+dictionary PlacesFaviconInit {
+  required DOMString url;
+  required ByteString pageGuid;
+  required DOMString faviconUrl;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesFavicon : PlacesEvent {
+  constructor(PlacesFaviconInit initDict);
+
+  /**
+   * The URI of the changed page.
+   */
+  readonly attribute DOMString url;
+
+  /**
+   * The unique id associated with the page.
+   */
+  readonly attribute ByteString pageGuid;
+
+  /**
+   * The URI of the new favicon.
+   */
+  readonly attribute DOMString faviconUrl;
+};
+
+dictionary PlacesVisitTitleInit {
+  required DOMString url;
+  required ByteString pageGuid;
+  required DOMString title;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesVisitTitle : PlacesEvent {
+  constructor(PlacesVisitTitleInit initDict);
+
+  /**
+   * The URI of the changed page.
+   */
+  readonly attribute DOMString url;
+
+  /**
+   * The unique id associated with the page.
+   */
+  readonly attribute ByteString pageGuid;
+
+  /**
+   * The title of the changed page.
+   */
+  readonly attribute DOMString title;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesHistoryCleared : PlacesEvent {
+  constructor();
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesRanking : PlacesEvent {
+  constructor();
+};
+
+dictionary PlacesVisitRemovedInit {
+  required DOMString url;
+  required ByteString pageGuid;
+  required unsigned short reason;
+  unsigned long transitionType = 0;
+  boolean isRemovedFromStore = false;
+  boolean isPartialVisistsRemoval = false;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesVisitRemoved : PlacesEvent {
+  /**
+   * Removed by the user.
+   */
+  const unsigned short REASON_DELETED = 0;
+
+  /**
+   * Removed by periodic expiration.
+   */
+  const unsigned short REASON_EXPIRED = 1;
+
+  constructor(PlacesVisitRemovedInit initDict);
+
+  /**
+   * The URI of the page.
+   */
+  readonly attribute DOMString url;
+
+  /**
+   * The unique id associated with the page.
+   */
+  readonly attribute ByteString pageGuid;
+
+  /**
+   * The reason of removal.
+   */
+  readonly attribute unsigned short reason;
+
+  /**
+   * One of nsINavHistoryService.TRANSITION_*
+   * NOTE: Please refer this attribute only when isRemovedFromStore is false.
+   *       Otherwise this will be 0.
+   */
+  readonly attribute unsigned long transitionType;
+
+  /**
+   * This will be true if the page is removed from store.
+   * If false, only visits were removed, but not the page.
+   */
+  readonly attribute boolean isRemovedFromStore;
+
+  /**
+   * This will be true if remains at least one visit to the page.
+   */
+  readonly attribute boolean isPartialVisistsRemoval;
+};
+
+[ChromeOnly, Exposed=Window]
+interface PlacesPurgeCaches : PlacesEvent {
+  constructor();
+};
diff --git a/dom/chrome-webidl/PlacesObservers.webidl b/dom/chrome-webidl/PlacesObservers.webidl
new file mode 100644
index 0000000000..662d8558ff
--- /dev/null
+++ b/dom/chrome-webidl/PlacesObservers.webidl
@@ -0,0 +1,31 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+callback PlacesEventCallback = undefined (sequence<PlacesEvent> events);
+
+[ChromeOnly, Exposed=Window]
+interface PlacesWeakCallbackWrapper {
+  constructor(PlacesEventCallback callback);
+};
+
+// Global singleton which should handle all events for places.
+[ChromeOnly, Exposed=Window]
+namespace PlacesObservers {
+  [Throws]
+  undefined addListener(sequence<PlacesEventType> eventTypes,
+                        PlacesEventCallback listener);
+  [Throws]
+  undefined addListener(sequence<PlacesEventType> eventTypes,
+                        PlacesWeakCallbackWrapper listener);
+  [Throws]
+  undefined removeListener(sequence<PlacesEventType> eventTypes,
+                           PlacesEventCallback listener);
+  [Throws]
+  undefined removeListener(sequence<PlacesEventType> eventTypes,
+                           PlacesWeakCallbackWrapper listener);
+  [Throws]
+  undefined notifyListeners(sequence<PlacesEvent> events);
+};
diff --git a/dom/chrome-webidl/PrecompiledScript.webidl b/dom/chrome-webidl/PrecompiledScript.webidl
new file mode 100644
index 0000000000..4a71f67fc8
--- /dev/null
+++ b/dom/chrome-webidl/PrecompiledScript.webidl
@@ -0,0 +1,43 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+dictionary ExecuteInGlobalOptions {
+  /**
+   * If `reportExceptions` is set to true and any exception happens
+   * while executing the script, the exceptions will automatically be logged
+   * in the console. This helps log the exception with the right global innerWindowID
+   * and make it display in the right DevTools console.
+   */
+  boolean reportExceptions = false;
+};
+
+/**
+ * Represents a pre-compiled JS script, which can be repeatedly executed in
+ * different globals without being re-parsed.
+ */
+[ChromeOnly, Exposed=Window]
+interface PrecompiledScript {
+  /**
+   * Executes the script in the context of, and with the security principal
+   * of, the given object's global. If compiled with a return value, returns
+   * the value of the script's last expression. Otherwise returns undefined.
+   */
+  [Throws]
+  any executeInGlobal(object global, optional ExecuteInGlobalOptions options = {});
+
+  /**
+   * The URL that the script was loaded from.
+   */
+  [Pure]
+  readonly attribute DOMString url;
+
+  /**
+   * True if the script was compiled with a return value, and will return the
+   * value of its last expression when executed.
+   */
+  [Pure]
+  readonly attribute boolean hasReturnValue;
+};
diff --git a/dom/chrome-webidl/PrioEncoder.webidl b/dom/chrome-webidl/PrioEncoder.webidl
new file mode 100644
index 0000000000..81c5bf0a4d
--- /dev/null
+++ b/dom/chrome-webidl/PrioEncoder.webidl
@@ -0,0 +1,20 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+[ChromeOnly, Exposed=Window]
+namespace PrioEncoder {
+  [Throws, NewObject]
+  PrioEncodedData encode(ByteString batchID, PrioParams params);
+};
+
+dictionary PrioParams {
+  required sequence<boolean> booleans;
+};
+
+dictionary PrioEncodedData {
+  Uint8Array a;
+  Uint8Array b;
+};
diff --git a/dom/chrome-webidl/PromiseDebugging.webidl b/dom/chrome-webidl/PromiseDebugging.webidl
new file mode 100644
index 0000000000..c4c4e8ec96
--- /dev/null
+++ b/dom/chrome-webidl/PromiseDebugging.webidl
@@ -0,0 +1,110 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/* This is a utility namespace for promise-debugging functionality */
+
+
+dictionary PromiseDebuggingStateHolder {
+  PromiseDebuggingState state = "pending";
+  any value;
+  any reason;
+};
+enum PromiseDebuggingState { "pending", "fulfilled", "rejected" };
+
+/**
+ * An observer for Promise that _may_ be leaking uncaught rejections.
+ *
+ * It is generally a programming error to leave a Promise rejected and
+ * not consume its rejection. The information exposed by this
+ * interface is designed to allow clients to track down such Promise,
+ * i.e. Promise that are currently
+ * - in `rejected` state;
+ * - last of their chain.
+ *
+ * Note, however, that a promise in such a state at the end of a tick
+ * may eventually be consumed in some ulterior tick. Implementers of
+ * this interface are responsible for presenting the information
+ * in a meaningful manner.
+ */
+[Exposed=Window]
+callback interface UncaughtRejectionObserver {
+  /**
+   * A Promise has been left in `rejected` state and is the
+   * last in its chain. If this callback returns true, the rejection
+   * will not be reported.
+   *
+   * @param p A currently uncaught Promise. If `p` is is eventually
+   * caught, i.e. if its `then` callback is called, `onConsumed` will
+   * be called.
+   */
+  boolean onLeftUncaught(object p);
+
+  /**
+   * A Promise previously left uncaught is not the last in its
+   * chain anymore.
+   *
+   * @param p A Promise that was previously left in uncaught state is
+   * now caught, i.e. it is not the last in its chain anymore.
+   */
+  undefined onConsumed(object p);
+};
+
+[ChromeOnly, Exposed=Window]
+namespace PromiseDebugging {
+  /**
+   * The various functions on this interface all expect to take promises but
+   * don't want the WebIDL behavior of assimilating random passed-in objects
+   * into promises.  They also want to treat Promise subclass instances as
+   * promises instead of wrapping them in a vanilla Promise, which is what the
+   * IDL spec says to do.  So we list all our arguments as "object" instead of
+   * "Promise" and check for them being a Promise internally.
+   */
+
+  /**
+   * Get the current state of the given promise.
+   */
+  [Throws]
+  PromiseDebuggingStateHolder getState(object p);
+
+  /**
+   * Return an identifier for a promise. This identifier is guaranteed
+   * to be unique to the current process.
+   */
+  [Throws]
+  DOMString getPromiseID(object p);
+
+  /**
+   * Return the stack to the promise's allocation point.  This can
+   * return null if the promise was not created from script.
+   */
+  [Throws]
+  object? getAllocationStack(object p);
+
+  /**
+   * Return the stack to the promise's rejection point, if the
+   * rejection happened from script.  This can return null if the
+   * promise has not been rejected or was not rejected from script.
+   */
+  [Throws]
+  object? getRejectionStack(object p);
+
+  /**
+   * Return the stack to the promise's fulfillment point, if the
+   * fulfillment happened from script.  This can return null if the
+   * promise has not been fulfilled or was not fulfilled from script.
+   */
+  [Throws]
+  object? getFullfillmentStack(object p);
+
+  /**
+   * Watching uncaught rejections on the current thread.
+   *
+   * Adding an observer twice will cause it to be notified twice
+   * of events.
+   */
+  undefined addUncaughtRejectionObserver(UncaughtRejectionObserver o);
+  boolean removeUncaughtRejectionObserver(UncaughtRejectionObserver o);
+};
diff --git a/dom/chrome-webidl/SessionStoreUtils.webidl b/dom/chrome-webidl/SessionStoreUtils.webidl
new file mode 100644
index 0000000000..9032c784c4
--- /dev/null
+++ b/dom/chrome-webidl/SessionStoreUtils.webidl
@@ -0,0 +1,169 @@
+/* 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/. */
+
+interface nsIDocShell;
+interface nsISupports;
+interface nsISessionStoreRestoreData;
+
+/**
+ * A callback passed to SessionStoreUtils.forEachNonDynamicChildFrame().
+ */
+callback SessionStoreUtilsFrameCallback = undefined (WindowProxy frame, unsigned long index);
+
+/**
+ * SessionStore utility functions implemented in C++ for performance reasons.
+ */
+[ChromeOnly, Exposed=Window]
+namespace SessionStoreUtils {
+  /**
+   * Calls the given |callback| once for each non-dynamic child frame of the
+   * given |window|.
+   */
+  [Throws]
+  undefined forEachNonDynamicChildFrame(WindowProxy window,
+                                        SessionStoreUtilsFrameCallback callback);
+
+  /**
+   * Takes the given listener, wraps it in a filter that filters out events from
+   * dynamic docShells, and adds that filter as a listener for the given event
+   * type on the given event target.  The listener that was added is returned
+   * (as nsISupports) so that it can later be removed via
+   * removeDynamicFrameFilteredListener.
+   *
+   * This is implemented as a native filter, rather than a JS-based one, for
+   * performance reasons.
+   */
+  [Throws]
+  nsISupports? addDynamicFrameFilteredListener(EventTarget target,
+                                               DOMString type,
+                                               any listener,
+                                               boolean useCapture,
+                                               optional boolean mozSystemGroup = false);
+
+  /**
+   * Remove the passed-in filtered listener from the given event target, if it's
+   * currently a listener for the given event type there.  The 'listener'
+   * argument must be something that was returned by
+   * addDynamicFrameFilteredListener.
+   *
+   * This is needed, instead of the normal removeEventListener, because the
+   * caller doesn't actually have something that WebIDL considers an
+   * EventListener.
+   */
+  [Throws]
+  undefined removeDynamicFrameFilteredListener(EventTarget target,
+                                               DOMString type,
+                                               nsISupports listener,
+                                               boolean useCapture,
+                                               optional boolean mozSystemGroup = false);
+
+  /*
+   * Save the docShell.allow* properties
+   */
+  ByteString collectDocShellCapabilities(nsIDocShell docShell);
+
+  /*
+   * Restore the docShell.allow* properties
+   */
+  undefined restoreDocShellCapabilities(nsIDocShell docShell,
+                                        ByteString disallowCapabilities);
+
+  /**
+   * Collects scroll position data for any given |frame| in the frame hierarchy.
+   *
+   * @param document (DOMDocument)
+   *
+   * @return {scroll: "x,y"} e.g. {scroll: "100,200"}
+   *         Returns null when there is no scroll data we want to store for the
+   *         given |frame|.
+   */
+  CollectedData? collectScrollPosition(WindowProxy window);
+
+  /**
+   * Restores scroll position data for any given |frame| in the frame hierarchy.
+   *
+   * @param frame (DOMWindow)
+   * @param value (object, see collectScrollPosition())
+   */
+  undefined restoreScrollPosition(Window frame, optional CollectedData data = {});
+
+  /**
+   * Collect form data for a given |frame| *not* including any subframes.
+   *
+   * The returned object may have an "id", "xpath", or "innerHTML" key or a
+   * combination of those three. Form data stored under "id" is for input
+   * fields with id attributes. Data stored under "xpath" is used for input
+   * fields that don't have a unique id and need to be queried using XPath.
+   * The "innerHTML" key is used for editable documents (designMode=on).
+   *
+   * Example:
+   *   {
+   *     id: {input1: "value1", input3: "value3"},
+   *     xpath: {
+   *       "/xhtml:html/xhtml:body/xhtml:input[@name='input2']" : "value2",
+   *       "/xhtml:html/xhtml:body/xhtml:input[@name='input4']" : "value4"
+   *     }
+   *   }
+   *
+   * @return object
+   *         Returns null when there is no scroll data
+   */
+  CollectedData? collectFormData(WindowProxy window);
+
+  boolean restoreFormData(Document document, optional CollectedData data = {});
+
+   nsISessionStoreRestoreData constructSessionStoreRestoreData();
+
+   [Throws]
+   Promise<undefined> initializeRestore(CanonicalBrowsingContext browsingContext,
+                                        nsISessionStoreRestoreData? data);
+
+   [NewObject]
+   Promise<undefined> restoreDocShellState(
+      CanonicalBrowsingContext browsingContext,
+      UTF8String? url,
+      ByteString? docShellCaps);
+
+   undefined restoreSessionStorageFromParent(
+     CanonicalBrowsingContext browsingContext,
+     record<UTF8String, record<DOMString, DOMString>> sessionStorage);
+};
+
+[GenerateConversionToJS, GenerateInit]
+dictionary CollectedFileListValue
+{
+  DOMString type = "file";
+  required sequence<DOMString> fileList;
+};
+
+[GenerateConversionToJS, GenerateInit]
+dictionary CollectedNonMultipleSelectValue
+{
+  required long selectedIndex;
+  required DOMString value;
+};
+
+// object contains either a CollectedFileListValue or a CollectedNonMultipleSelectValue or Sequence<DOMString>
+typedef (DOMString or boolean or object) CollectedFormDataValue;
+
+dictionary CollectedData
+{
+  ByteString scroll;
+  record<DOMString, CollectedFormDataValue> id;
+  record<DOMString, CollectedFormDataValue> xpath;
+  DOMString innerHTML;
+  ByteString url;
+  // mChildren contains CollectedData instances
+  sequence<object?> children;
+};
+
+dictionary InputElementData {
+  sequence<DOMString> id;
+  sequence<DOMString> type;
+  sequence<long> valueIdx;
+  sequence<long> selectedIndex;
+  sequence<DOMString> selectVal;
+  sequence<DOMString> strVal;
+  sequence<boolean> boolVal;
+};
diff --git a/dom/chrome-webidl/StructuredCloneHolder.webidl b/dom/chrome-webidl/StructuredCloneHolder.webidl
new file mode 100644
index 0000000000..235464a059
--- /dev/null
+++ b/dom/chrome-webidl/StructuredCloneHolder.webidl
@@ -0,0 +1,32 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+/**
+ * A holder for structured-clonable data which can itself be cloned with
+ * little overhead, and deserialized into an arbitrary global.
+ */
+[ChromeOnly, Exposed=(Window,Worker)]
+interface StructuredCloneHolder {
+  /**
+   * Serializes the given value to an opaque structured clone blob, and
+   * returns the result.
+   *
+   * The serialization happens in the compartment of the given global or, if no
+   * global is provided, the compartment of the data value.
+   */
+  [Throws]
+  constructor(any data, optional object? global = null);
+
+  /**
+   * Deserializes the structured clone data in the scope of the given global,
+   * and returns the result.
+   *
+   * If `keepData` is true, the structured clone data is preserved, and can be
+   * deserialized repeatedly. Otherwise, it is immediately discarded.
+   */
+  [Throws]
+  any deserialize(object global, optional boolean keepData = false);
+};
diff --git a/dom/chrome-webidl/TelemetryStopwatch.webidl b/dom/chrome-webidl/TelemetryStopwatch.webidl
new file mode 100644
index 0000000000..92f8a0d630
--- /dev/null
+++ b/dom/chrome-webidl/TelemetryStopwatch.webidl
@@ -0,0 +1,238 @@
+/* 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/.
+ */
+
+typedef DOMString HistogramID;
+typedef DOMString HistogramKey;
+
+[ChromeOnly, Exposed=Window]
+namespace TelemetryStopwatch {
+  /**
+   * Starts a timer associated with a telemetry histogram. The timer can be
+   * directly associated with a histogram, or with a pair of a histogram and
+   * an object.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   *              associated with this object, meaning that multiple
+   *              timers for the same histogram may be run
+   *              concurrently, as long as they are associated with
+   *              different objects.
+   * @param [options.inSeconds=false] - record elapsed time for this
+   *        histogram in seconds instead of milliseconds. Defaults to
+   *        false.
+   *
+   * @returns True if the timer was successfully started, false
+   *          otherwise. If a timer already exists, it can't be
+   *          started again, and the existing one will be cleared in
+   *          order to avoid measurements errors.
+   */
+  boolean start(HistogramID histogram, optional object? obj = null,
+                optional TelemetryStopwatchOptions options = {});
+
+  /**
+   * Returns whether a timer associated with a telemetry histogram is currently
+   * running. The timer can be directly associated with a histogram, or with a
+   * pair of a histogram and an object.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   *              associated with this object, meaning that multiple
+   *              timers for the same histogram may be run
+   *              concurrently, as long as they are associated with
+   *              different objects.
+   *
+   * @returns True if the timer exists and is currently running.
+   */
+  boolean running(HistogramID histogram, optional object? obj = null);
+
+  /**
+   * Deletes the timer associated with a telemetry histogram. The timer can be
+   * directly associated with a histogram, or with a pair of a histogram and
+   * an object. Important: Only use this method when a legitimate cancellation
+   * should be done.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   *              associated with this object, meaning that multiple
+   *              timers or a same histogram may be run concurrently,
+   *              as long as they are associated with different
+   *              objects.
+   *
+   * @returns True if the timer exist and it was cleared, False
+   *          otherwise.
+   */
+  boolean cancel(HistogramID histogram, optional object? obj = null);
+
+  /**
+   * Returns the elapsed time for a particular stopwatch. Primarily for
+   * debugging purposes. Must be called prior to finish.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *                    if an invalid name is given, the function will
+   *                    throw.
+   *
+   * @param obj - Optional parameter which associates the histogram
+   *              timer with the given object.
+   *
+   * @param canceledOkay - Optional parameter which will suppress any
+   *                       warnings that normally fire when a stopwatch
+   *                       is finished after being cancelled. Defaults
+   *                       to false.
+   *
+   * @returns Time in milliseconds or -1 if the stopwatch was not
+   *          found.
+   */
+  long timeElapsed(HistogramID histogram,
+                   optional object? obj = null,
+                   optional boolean canceledOkay = false);
+
+  /**
+   * Stops the timer associated with the given histogram (and object),
+   * calculates the time delta between start and finish, and adds the value
+   * to the histogram.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param obj - Optional parameter which associates the histogram
+   *              timer with the given object.
+   *
+   * @param canceledOkay - Optional parameter which will suppress any
+   *                       warnings that normally fire when a stopwatch
+   *                       is finished after being cancelled. Defaults
+   *                       to false.
+   *
+   * @returns True if the timer was succesfully stopped and the data
+   *          was added to the histogram, false otherwise.
+   */
+  boolean finish(HistogramID histogram,
+                 optional object? obj = null,
+                 optional boolean canceledOkay = false);
+
+  /**
+   * Starts a timer associated with a keyed telemetry histogram. The timer can
+   * be directly associated with a histogram and its key. Similarly to
+   * @see{TelemetryStopwatch.start} the histogram and its key can be associated
+   * with an object. Each key may have multiple associated objects and each
+   * object can be associated with multiple keys.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param key - a string which must be a valid histgram key.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   *              associated with this object, meaning that multiple
+   *              timers for the same histogram may be run
+   *              concurrently,as long as they are associated with
+   *              different objects.
+   * @param [options.inSeconds=false] - record elapsed time for this
+   *         histogram in seconds instead of milliseconds. Defaults to
+   *         false.
+   *
+   * @returns True if the timer was successfully started, false
+   *          otherwise. If a timer already exists, it can't be
+   *          started again, and the existing one will be cleared in
+   *          order to avoid measurements errors.
+   */
+  boolean startKeyed(HistogramID histogram, HistogramKey key,
+                     optional object? obj = null,
+                     optional TelemetryStopwatchOptions options = {});
+
+  /**
+   * Returns whether a timer associated with a telemetry histogram is currently
+   * running. Similarly to @see{TelemetryStopwatch.running} the timer and its
+   * key can be associated with an object. Each key may have multiple associated
+   * objects and each object can be associated with multiple keys.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param key - a string which must be a valid histgram key.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   *              associated with this object, meaning that multiple
+   *              timers for the same histogram may be run
+   *              concurrently, as long as they are associated with
+   *              different objects.
+   *
+   * @returns True if the timer exists and is currently running.
+   */
+  boolean runningKeyed(HistogramID histogram, HistogramKey key,
+                       optional object? obj = null);
+
+  /**
+   * Deletes the timer associated with a keyed histogram. Important: Only use
+   * this method when a legitimate cancellation should be done.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param key - a string which must be a valid histgram key.
+   *
+   * @param obj - Optional parameter. If specified, the timer
+   *              associated with this object is deleted.
+   *
+   * @returns True if the timer exist and it was cleared, False
+   *          otherwise.
+   */
+  boolean cancelKeyed(HistogramID histogram, HistogramKey key,
+                      optional object? obj = null);
+
+  /**
+   * Returns the elapsed time for a particular stopwatch. Primarily for
+   * debugging purposes. Cannot be called after finish().
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param key - a string which must be a valid histgram key.
+   *
+   * @param obj - Optional parameter. If specified, the timer
+   *              associated with this object is used to calculate
+   *              the elapsed time.
+   *
+   * @returns Time in milliseconds or -1 if the stopwatch was not
+   *          found.
+   */
+  long timeElapsedKeyed(HistogramID histogram, HistogramKey key,
+                        optional object? obj = null,
+                        optional boolean canceledOkay = false);
+
+  /**
+   * Stops the timer associated with the given keyed histogram (and object),
+   * calculates the time delta between start and finish, and adds the value
+   * to the keyed histogram.
+   *
+   * @param histogram - a string which must be a valid histogram name.
+   *
+   * @param key - a string which must be a valid histgram key.
+   *
+   * @param obj - optional parameter which associates the histogram
+   *              timer with the given object.
+   *
+   * @param canceledOkay - Optional parameter which will suppress any
+   *                       warnings that normally fire when a stopwatch
+   *                       is finished after being cancelled. Defaults
+   *                       to false.
+   *
+   * @returns True if the timer was succesfully stopped and the data
+   *          was added to the histogram, false otherwise.
+   */
+  boolean finishKeyed(HistogramID histogram, HistogramKey key,
+                      optional object? obj = null,
+                      optional boolean canceledOkay = false);
+
+  /**
+   * Set the testing mode. Used by tests.
+   */
+  undefined setTestModeEnabled(optional boolean testing = true);
+};
+
+dictionary TelemetryStopwatchOptions {
+  /**
+   * If true, record elapsed time for this histogram in seconds instead of
+   * milliseconds.
+   */
+  boolean inSeconds = false;
+};
diff --git a/dom/chrome-webidl/UniFFI.webidl b/dom/chrome-webidl/UniFFI.webidl
new file mode 100644
index 0000000000..7a3f68fbbd
--- /dev/null
+++ b/dom/chrome-webidl/UniFFI.webidl
@@ -0,0 +1,107 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Interface for making UniFFI scaffolding calls
+//
+// Gecko uses UniFFI to generate privileged JS bindings for Rust components.
+// UniFFI defines a C-ABI FFI layer for calling into Rust, called the
+// scaffolding. This interface is a bridge that allows the JS code to make
+// scaffolding calls
+//
+// See https://mozilla.github.io/uniffi-rs/ for details.
+
+// Define some ID types to identify various parts of the UDL interfaces.  Using
+// these IDs, allow this .webidl file to remain static, but support new
+// interfaces.  Using IDs is that the C++ and JS code need to agree on their
+// meaning, which is handled by
+// toolkit/components/uniffi-bindgen-gecko-js/src/ci_list.rs.
+
+// Identifies a scaffolding function.
+typedef unsigned long long UniFFIFunctionId;
+
+// Identifies a pointer type
+typedef unsigned long long UniFFIPointerId;
+
+// Identifies a callback interface
+typedef unsigned long UniFFICallbackInterfaceId;
+
+// Identifies a method of a callback interface
+typedef unsigned long UniFFICallbackMethodId;
+
+// Handle for a callback interface instance
+typedef unsigned long long UniFFICallbackObjectHandle;
+
+// Opaque type used to represent a pointer from Rust
+[ChromeOnly, Exposed=Window]
+interface UniFFIPointer {};
+
+// Types that can be passed or returned from scaffolding functions
+//
+// - double is used for all numeric types and types which the JS code coerces
+//   to an int including Boolean and CallbackInterface.
+// - ArrayBuffer is used for RustBuffer
+// - UniFFIPointer is used for Arc pointers
+typedef (double or ArrayBuffer or UniFFIPointer) UniFFIScaffoldingType;
+
+// The result of a call into UniFFI scaffolding call
+enum UniFFIScaffoldingCallCode {
+   "success",         // Successful return
+   "error",           // Rust Err return
+   "internal-error",  // Internal/unexpected error
+};
+
+dictionary UniFFIScaffoldingCallResult {
+    required UniFFIScaffoldingCallCode code;
+    // For success, this will be the return value for non-void returns
+    // For error, this will be an ArrayBuffer storing the serialized error value
+    UniFFIScaffoldingType data;
+    // For internal-error, this will be a utf-8 string describing the error
+    ByteString internalErrorMessage;
+};
+
+// JS handler for calling a CallbackInterface method.
+// The arguments and return value are always packed into an ArrayBuffer
+callback UniFFICallbackHandler = undefined (UniFFICallbackObjectHandle objectId, UniFFICallbackMethodId methodId, ArrayBuffer aArgs);
+
+// Functions to facilitate UniFFI scaffolding calls
+[ChromeOnly, Exposed=Window]
+namespace UniFFIScaffolding {
+  // Call a scaffolding function on the worker thread.
+  //
+  // id is a unique identifier for the function, known to both the C++ and JS code
+  [Throws]
+  Promise<UniFFIScaffoldingCallResult> callAsync(UniFFIFunctionId id, UniFFIScaffoldingType... args);
+
+  // Call a scaffolding function on the main thread
+  //
+  // id is a unique identifier for the function, known to both the C++ and JS code
+  [Throws]
+  UniFFIScaffoldingCallResult callSync(UniFFIFunctionId id, UniFFIScaffoldingType... args);
+
+  // Read a UniFFIPointer from an ArrayBuffer
+  //
+  // id is a unique identifier for the pointer type, known to both the C++ and JS code
+  [Throws]
+  UniFFIPointer readPointer(UniFFIPointerId id, ArrayBuffer buff, long position);
+
+  // Write a UniFFIPointer to an ArrayBuffer
+  //
+  // id is a unique identifier for the pointer type, known to both the C++ and JS code
+  [Throws]
+  undefined writePointer(UniFFIPointerId id, UniFFIPointer ptr, ArrayBuffer buff, long position);
+
+  // Register the global calblack handler
+  //
+  // This will be used to invoke all calls for a CallbackInterface.
+  // interfaceId is a unique identifier for the callback interface, known to both the C++ and JS code
+  [Throws]
+  undefined registerCallbackHandler(UniFFICallbackInterfaceId interfaceId, UniFFICallbackHandler handler);
+
+  // Deregister the global calblack handler
+  //
+  // This is called at shutdown to clear out the reference to the JS function.
+  [Throws]
+  undefined deregisterCallbackHandler(UniFFICallbackInterfaceId interfaceId);
+};
diff --git a/dom/chrome-webidl/UserInteraction.webidl b/dom/chrome-webidl/UserInteraction.webidl
new file mode 100644
index 0000000000..ccde57dcac
--- /dev/null
+++ b/dom/chrome-webidl/UserInteraction.webidl
@@ -0,0 +1,113 @@
+/* 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/.
+ */
+
+[ChromeOnly, Exposed=Window]
+namespace UserInteraction {
+  /**
+   * Starts a timer associated with a UserInteraction ID. The timer can be
+   * directly associated with a UserInteraction ID, or with a pair of a
+   * UserInteraction ID and an object.
+   *
+   * @param id - the interaction being recorded, as
+   * declared in UserInteractions.yaml. This is also the annotation
+   * key that will be set in the BHR hang report if a hang occurs
+   * before the UserInteraction is finished.
+   *
+   * @param value - a value to be set on the key in the event
+   * that a hang occurs when the timer is running. This value is limited
+   * to 50 characters to avoid abuse, and if the value exceeds that limit
+   * then no timer is started, an error is printed, and this function returns
+   * false.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   * associated with this object, meaning that multiple timers for the
+   * same annotation key may be run concurrently, as long as they are
+   * associated with different objects.
+   *
+   * @returns True if the timer was successfully started, false otherwise.
+   * If a timer already exists, it will be overwritten, and the new timer
+   * will include a "(clobbered)" suffix in any BHR annotations that get
+   * created.
+   */
+  boolean start(DOMString id,
+                UTF8String value,
+                optional object? obj = null);
+
+  /**
+   * Updates an already-running timer associated with a UserInteraction ID
+   * (and object) with a new value string.
+   *
+   * @param id - the interaction being recorded, as
+   * declared in UserInteractions.yaml. This is also the annotation
+   * key that will be set in the BHR hang report if a hang occurs
+   * before the UserInteraction is finished.
+   *
+   * @param value - a new value to be set on the key in the event
+   * that a hang occurs when the timer is running. This value is limited
+   * to 50 characters to avoid abuse.
+   *
+   * @param obj - Optional parameter. If specified, the timer is
+   * associated with this object, meaning that multiple timers for the
+   * same annotation key may be run concurrently, as long as they are
+   * associated with different objects.
+   *
+   * @returns True if the timer was successfully updated, false
+   * otherwise.
+   */
+  boolean update(DOMString id,
+                 UTF8String value,
+                 optional object? obj = null);
+
+  /**
+   * Cancels the timer associated with the given UserInteraction ID
+   * (and object) and does not add the profiler marker for it.
+   *
+   * @param id - the interaction being recorded, as
+   * declared in UserInteractions.yaml.
+   *
+   * @param obj - Optional parameter which associates the
+   * timer with the given object.
+   *
+   * @returns True if the timer was successfully stopped.
+   */
+  boolean cancel(DOMString id, optional object? obj = null);
+
+  /**
+   * Returns whether a UserInteraction timer is currently running.
+   *
+   * @param id - the ID of the interaction to check, as declared in
+   * UserInteractions.yaml.
+   *
+   * @param obj - Optional parameter which checks for a timer associated
+   * with this particular object. If you're checking for a running timer
+   * that was started with an object, you'll need to pass in that same
+   * object here to check its running state.
+   *
+   * @returns True if the timer exists and is currently running.
+   */
+  boolean running(DOMString id, optional object? obj = null);
+
+  /**
+   * Stops the timer associated with the given UserInteraction ID
+   * (and object), calculates the time delta between start and finish,
+   * and adds a profiler marker with that time range.
+   *
+   * @param id - the interaction being recorded, as
+   * declared in UserInteractions.yaml.
+   *
+   * @param obj - Optional parameter which associates the
+   * timer with the given object.
+   *
+   * @param additionalText - Optional parameter with includes additional
+   * text in the profiler marker. This text is not included in the hang
+   * annotation.
+   *
+   * @returns True if the timer was successfully stopped and the data
+   * was added to the profile.
+   */
+  boolean finish(DOMString id,
+                 optional object? obj = null,
+                 optional UTF8String additionalText);
+};
diff --git a/dom/chrome-webidl/WebExtensionContentScript.webidl b/dom/chrome-webidl/WebExtensionContentScript.webidl
new file mode 100644
index 0000000000..4eadfbcb09
--- /dev/null
+++ b/dom/chrome-webidl/WebExtensionContentScript.webidl
@@ -0,0 +1,174 @@
+/* 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/. */
+
+interface LoadInfo;
+interface URI;
+interface WindowProxy;
+
+typedef (MatchPatternSet or sequence<DOMString>) MatchPatternSetOrStringSequence;
+typedef (MatchGlob or UTF8String) MatchGlobOrString;
+
+[ChromeOnly, Exposed=Window]
+interface MozDocumentMatcher {
+  [Throws]
+  constructor(MozDocumentMatcherInit options);
+
+  /**
+   * Returns true if the script's match and exclude patterns match the given
+   * URI, without reference to attributes such as `allFrames`.
+   */
+  boolean matchesURI(URI uri);
+
+  /**
+   * Returns true if the given window matches. This should be used to
+   * determine whether to run a script in a window at load time. Use
+   * ignorePermissions to match without origin permissions in MV3.
+   */
+  boolean matchesWindowGlobal(WindowGlobalChild windowGlobal,
+                              optional boolean ignorePermissions = false);
+
+  /**
+   * If true, match all frames. If false, match only top-level frames.
+   */
+  [Constant]
+  readonly attribute boolean allFrames;
+
+  /**
+   * If we can't check extension has permissions to access the URI upfront,
+   * set the flag to perform the origin check at runtime, upon matching.
+   * This is always true in MV3, where host permissions are optional.
+   */
+  [Constant]
+  readonly attribute boolean checkPermissions;
+
+  /**
+   * If true, this (misleadingly-named, but inherited from Chrome) attribute
+   * causes us to match frames with URLs which inherit a principal that
+   * matches one of the match patterns, such as about:blank or about:srcdoc.
+   * If false, we only match frames with an explicit matching URL.
+   */
+  [Constant]
+  readonly attribute boolean matchAboutBlank;
+
+  /**
+   * The outer window ID of the frame in which to run the script, or 0 if it
+   * should run in the top-level frame. Should only be used for
+   * dynamically-injected scripts.
+   */
+  [Constant]
+  readonly attribute unsigned long long? frameID;
+
+  /**
+   * The set of match patterns for URIs of pages in which this script should
+   * run. This attribute is mandatory, and is a prerequisite for all other
+   * match patterns.
+   */
+  [Constant]
+  readonly attribute MatchPatternSet matches;
+
+  /**
+   * A set of match patterns for URLs in which this script should not run,
+   * even if they match other include patterns or globs.
+   */
+  [Constant]
+  readonly attribute MatchPatternSet? excludeMatches;
+
+  /**
+   * The originAttributesPattern for which this script should be enabled for.
+   */
+  [Constant, Throws]
+  readonly attribute any originAttributesPatterns;
+
+  /**
+   * The policy object for the extension that this matcher belongs to.
+   */
+  [Constant]
+  readonly attribute WebExtensionPolicy? extension;
+};
+
+dictionary MozDocumentMatcherInit {
+  boolean allFrames = false;
+
+  boolean checkPermissions = false;
+
+  sequence<OriginAttributesPatternDictionary>? originAttributesPatterns = null;
+
+  boolean matchAboutBlank = false;
+
+  unsigned long long? frameID = null;
+
+  required MatchPatternSetOrStringSequence matches;
+
+  MatchPatternSetOrStringSequence? excludeMatches = null;
+
+  sequence<MatchGlobOrString>? includeGlobs = null;
+
+  sequence<MatchGlobOrString>? excludeGlobs = null;
+
+  boolean hasActiveTabPermission = false;
+};
+
+/**
+ * Describes the earliest point in the load cycle at which a script should
+ * run.
+ */
+enum ContentScriptRunAt {
+  /**
+   * The point in the load cycle just after the document element has been
+   * inserted, before any page scripts have been allowed to run.
+   */
+  "document_start",
+  /**
+   * The point after which the page DOM has fully loaded, but before all page
+   * resources have necessarily been loaded. Corresponds approximately to the
+   * DOMContentLoaded event.
+   */
+  "document_end",
+  /**
+   * The first point after the page and all of its resources has fully loaded
+   * when the event loop is idle, and can run scripts without delaying a paint
+   * event.
+   */
+  "document_idle",
+};
+
+[ChromeOnly, Exposed=Window]
+interface WebExtensionContentScript : MozDocumentMatcher {
+  [Throws]
+  constructor(WebExtensionPolicy extension,
+              WebExtensionContentScriptInit options);
+
+  /**
+   * The earliest point in the load cycle at which this script should run. For
+   * static content scripts, in extensions which were present at browser
+   * startup, the browser makes every effort to make sure that the script runs
+   * no later than this point in the load cycle. For dynamic content scripts,
+   * and scripts from extensions installed during this session, the scripts
+   * may run at a later point.
+   */
+  [Constant]
+  readonly attribute ContentScriptRunAt runAt;
+
+  /**
+   * A set of paths, relative to the extension root, of CSS sheets to inject
+   * into matching pages.
+   */
+  [Cached, Constant, Frozen]
+  readonly attribute sequence<DOMString> cssPaths;
+
+  /**
+   * A set of paths, relative to the extension root, of JavaScript scripts to
+   * execute in matching pages.
+   */
+  [Cached, Constant, Frozen]
+  readonly attribute sequence<DOMString> jsPaths;
+};
+
+dictionary WebExtensionContentScriptInit : MozDocumentMatcherInit {
+  ContentScriptRunAt runAt = "document_idle";
+
+  sequence<DOMString> cssPaths = [];
+
+  sequence<DOMString> jsPaths = [];
+};
diff --git a/dom/chrome-webidl/WebExtensionPolicy.webidl b/dom/chrome-webidl/WebExtensionPolicy.webidl
new file mode 100644
index 0000000000..8a486a9231
--- /dev/null
+++ b/dom/chrome-webidl/WebExtensionPolicy.webidl
@@ -0,0 +1,320 @@
+/* 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/. */
+
+interface URI;
+interface WindowProxy;
+
+callback WebExtensionLocalizeCallback = DOMString (DOMString unlocalizedText);
+
+/**
+ * Defines the platform-level policies for a WebExtension, including its
+ * permissions and the characteristics of its moz-extension: URLs.
+ */
+[ChromeOnly, Exposed=Window]
+interface WebExtensionPolicy {
+  [Throws]
+  constructor(WebExtensionInit options);
+
+  /**
+   * The add-on's internal ID, as specified in its manifest.json file or its
+   * XPI signature.
+   */
+  [Constant, StoreInSlot]
+  readonly attribute DOMString id;
+
+  /**
+   * The hostname part of the extension's moz-extension: URLs. This value is
+   * generated randomly at install time.
+   */
+  [Constant, StoreInSlot]
+  readonly attribute ByteString mozExtensionHostname;
+
+  /**
+   * The file: or jar: URL to use for the base of the extension's
+   * moz-extension: URL root.
+   */
+  [Constant]
+  readonly attribute ByteString baseURL;
+
+  /**
+   * The extension's user-visible name.
+   */
+  [Constant]
+  readonly attribute DOMString name;
+
+  /**
+   * The add-on's internal type as determined by parsing the manifest.json file.
+   */
+  [Constant]
+  readonly attribute DOMString type;
+
+  /**
+   * Whether the extension has access to privileged features
+   */
+  [Constant]
+  readonly attribute boolean isPrivileged;
+
+  /**
+   * Whether the extension is installed temporarily
+   */
+  [Constant]
+  readonly attribute boolean temporarilyInstalled;
+
+  /**
+   * The manifest version in use by the extension.
+   */
+  [Constant]
+  readonly attribute unsigned long manifestVersion;
+
+  /**
+   * The base content security policy string to apply on extension
+   * pages for this extension.  The baseCSP is specific to the
+   * manifest version.  If the manifest version is 3 or higher it
+   * is also applied to content scripts.
+   */
+  [Constant]
+  readonly attribute DOMString baseCSP;
+
+  /**
+   * The content security policy string to apply to all pages loaded from the
+   * extension's moz-extension: protocol.  If one is not provided by the
+   * extension the default value from preferences is used.
+   * See extensions.webextensions.default-content-security-policy.
+   */
+  [Constant]
+  readonly attribute DOMString extensionPageCSP;
+
+  /**
+   * The list of currently-active permissions for the extension, as specified
+   * in its manifest.json file. May be updated to reflect changes in the
+   * extension's optional permissions.
+   */
+  [Cached, Frozen, Pure]
+  attribute sequence<DOMString> permissions;
+
+  /**
+   * Match patterns for the set of web origins to which the extension is
+   * currently allowed access. May be updated to reflect changes in the
+   * extension's optional permissions.
+   */
+  [Pure]
+  attribute MatchPatternSet allowedOrigins;
+
+  /**
+   * The set of content scripts active for this extension.
+   */
+  [Cached, Frozen, Pure]
+  readonly attribute sequence<WebExtensionContentScript> contentScripts;
+
+  /**
+   * True if the extension is currently active, false otherwise. When active,
+   * the extension's moz-extension: protocol will point to the given baseURI,
+   * and the set of policies for this object will be active for its ID.
+   *
+   * Only one extension policy with a given ID or hostname may be active at a
+   * time. Attempting to activate a policy while a conflicting policy is
+   * active will raise an error.
+   */
+  [Affects=Everything, SetterThrows]
+  attribute boolean active;
+
+  /**
+   * True if both e10s and webextensions.remote are enabled.  This must be
+   * used instead of checking the remote pref directly since remote extensions
+   * require both to be enabled.
+   */
+  static readonly attribute boolean useRemoteWebExtensions;
+
+  /**
+   * True if the calling process is an extension process.
+   */
+  static readonly attribute boolean isExtensionProcess;
+
+  /**
+   * Whether the background.service_worker in the extension manifest.json file
+   * is enabled.
+   *
+   * NOTE: **do not use Services.prefs to retrieve the value of the undelying pref**
+   *
+   * It is defined in StaticPrefs.yaml as `mirror: once` and so checking
+   * its current value using Services.prefs doesn't guarantee that it does
+   * match the value as accessible from the C++ layers, and unexpected issue
+   * may be possible if different code has a different idea of its value.
+   */
+  static readonly attribute boolean backgroundServiceWorkerEnabled;
+
+  /**
+   * Set based on the manifest.incognito value:
+   * If "spanning" or "split" will be true.
+   * If "not_allowed" will be false.
+   */
+  [Pure]
+  readonly attribute boolean privateBrowsingAllowed;
+
+  /**
+   * Returns true if the extension can access a window.  Access is
+   * determined by matching the windows private browsing context
+   * with privateBrowsingMode.  This does not, and is not meant to
+   * handle specific differences between spanning and split mode.
+   */
+  [Affects=Nothing]
+  boolean canAccessWindow(WindowProxy window);
+
+  /**
+   * Returns true if the extension has cross-origin access to the given URI.
+   */
+  boolean canAccessURI(URI uri, optional boolean explicit = false);
+
+  /**
+   * Returns true if the extension currently has the given permission.
+   */
+  boolean hasPermission(DOMString permission);
+
+  /**
+   * Returns true if the given path relative to the extension's moz-extension:
+   * URL root is listed as a web accessible path. Access checks on a path, such
+   * as performed in nsScriptSecurityManager, use sourceMayAccessPath below.
+   */
+  boolean isWebAccessiblePath(UTF8String pathname);
+
+  /**
+   * Returns true if the given path relative to the extension's moz-extension:
+   * URL root may be accessed by web content at sourceURI.  For Manifest V2,
+   * sourceURI is ignored and the path must merely be listed as web accessible.
+   */
+  boolean sourceMayAccessPath(URI sourceURI, UTF8String pathname);
+
+  /**
+   * Replaces localization placeholders in the given string with localized
+   * text from the extension's currently active locale.
+   */
+  DOMString localize(DOMString unlocalizedText);
+
+  /**
+   * Returns the moz-extension: URL for the given path.
+   */
+  [Throws]
+  DOMString getURL(optional DOMString path = "");
+
+  /**
+   * Register a new content script programmatically.
+   */
+  [Throws]
+  undefined registerContentScript(WebExtensionContentScript script);
+
+  /**
+   * Unregister a content script.
+   */
+  [Throws]
+  undefined unregisterContentScript(WebExtensionContentScript script);
+
+  /**
+   * Injects the extension's content script into all existing matching windows.
+   */
+  [Throws]
+  undefined injectContentScripts();
+
+  /**
+   * Returns the list of currently active extension policies.
+   */
+  static sequence<WebExtensionPolicy> getActiveExtensions();
+
+  /**
+   * Returns the currently-active policy for the extension with the given ID,
+   * or null if no policy is active for that ID.
+   */
+  static WebExtensionPolicy? getByID(DOMString id);
+
+  /**
+   * Returns the currently-active policy for the extension with the given
+   * moz-extension: hostname, or null if no policy is active for that
+   * hostname.
+   */
+  static WebExtensionPolicy? getByHostname(ByteString hostname);
+
+  /**
+   * Returns the currently-active policy for the extension extension URI, or
+   * null if the URI is not an extension URI, or no policy is currently active
+   * for it.
+   */
+  static WebExtensionPolicy? getByURI(URI uri);
+
+  /**
+   * Returns true if the URI is restricted for any extension.
+   */
+  static boolean isRestrictedURI(URI uri);
+
+  /**
+   * When present, the extension is not yet ready to load URLs. In that case,
+   * this policy object is a stub, and the attribute contains a promise which
+   * resolves to a new, non-stub policy object when the extension is ready.
+   *
+   * This may be used to delay operations, such as loading extension pages,
+   * which depend on extensions being fully initialized.
+   *
+   * Note: This will always be either a Promise<WebExtensionPolicy?> or null,
+   * but the WebIDL grammar does not allow us to specify a nullable Promise
+   * type.
+   *
+   * Note: This could resolve to null when the startup was interrupted.
+   */
+  readonly attribute object? readyPromise;
+
+  /**
+   * Returns true if the given worker script URL matches the background
+   * service worker url declared in the extension manifest.json file.
+   */
+  boolean isManifestBackgroundWorker(DOMString workerURL);
+
+  /**
+   * Get the unique BrowsingContextGroup ID which will be used for toplevel
+   * page loads from this extension.
+   *
+   * This method will raise an exception if called from outside of the parent
+   * process, or if the extension is inactive.
+   */
+  [Throws]
+  readonly attribute unsigned long long browsingContextGroupId;
+};
+
+dictionary WebAccessibleResourceInit {
+  required sequence<MatchGlobOrString> resources;
+  MatchPatternSetOrStringSequence? matches = null;
+  sequence<DOMString>? extension_ids = null;
+};
+
+dictionary WebExtensionInit {
+  required DOMString id;
+
+  required ByteString mozExtensionHostname;
+
+  required DOMString baseURL;
+
+  DOMString name = "";
+
+  DOMString type = "";
+
+  boolean isPrivileged = false;
+
+  boolean temporarilyInstalled = false;
+
+  required WebExtensionLocalizeCallback localizeCallback;
+
+  required MatchPatternSetOrStringSequence allowedOrigins;
+
+  sequence<DOMString> permissions = [];
+
+  sequence<WebAccessibleResourceInit> webAccessibleResources = [];
+
+  sequence<WebExtensionContentScriptInit> contentScripts = [];
+
+  // The use of a content script csp is determined by the manifest version.
+  unsigned long manifestVersion = 2;
+  DOMString? extensionPageCSP = null;
+
+  sequence<DOMString>? backgroundScripts = null;
+  DOMString? backgroundWorkerScript = null;
+
+  Promise<WebExtensionPolicy?> readyPromise;
+};
diff --git a/dom/chrome-webidl/WindowGlobalActors.webidl b/dom/chrome-webidl/WindowGlobalActors.webidl
new file mode 100644
index 0000000000..e860e98891
--- /dev/null
+++ b/dom/chrome-webidl/WindowGlobalActors.webidl
@@ -0,0 +1,189 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+interface Principal;
+interface URI;
+interface nsIDocShell;
+interface RemoteTab;
+interface nsIDOMProcessParent;
+
+[Exposed=Window, ChromeOnly]
+interface WindowContext {
+  readonly attribute BrowsingContext? browsingContext;
+
+  readonly attribute WindowGlobalChild? windowGlobalChild; // in-process only
+
+  readonly attribute unsigned long long innerWindowId;
+
+  readonly attribute WindowContext? parentWindowContext;
+
+  readonly attribute WindowContext topWindowContext;
+
+  readonly attribute boolean isInProcess;
+
+  // True if this WindowContext is currently frozen in the BFCache.
+  readonly attribute boolean isInBFCache;
+
+  // True if this window has registered a "beforeunload" event handler.
+  readonly attribute boolean hasBeforeUnload;
+
+  // True if the principal of this window is for a local ip address.
+  readonly attribute boolean isLocalIP;
+
+  /**
+   * Partially determines whether script execution is allowed in this
+   * BrowsingContext. Script execution will be permitted only if this
+   * attribute is true and script execution is allowed in the owner
+   * BrowsingContext.
+   *
+   * May only be set in the context's owning process.
+   */
+  [SetterThrows] attribute boolean allowJavascript;
+};
+
+// Keep this in sync with nsIContentViewer::PermitUnloadAction.
+enum PermitUnloadAction {
+  "prompt",
+  "dontUnload",
+  "unload",
+};
+
+[Exposed=Window, ChromeOnly]
+interface WindowGlobalParent : WindowContext {
+  readonly attribute boolean isClosed;
+
+  readonly attribute boolean isCurrentGlobal;
+
+  readonly attribute unsigned long long outerWindowId;
+  readonly attribute unsigned long long contentParentId;
+
+  readonly attribute long osPid;
+
+  // A WindowGlobalParent is the root in its process if it has no parent, or its
+  // embedder is in a different process.
+  readonly attribute boolean isProcessRoot;
+
+  // Is the document loaded in this WindowGlobalParent the initial document
+  // implicitly created while "creating a new browsing context".
+  // https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-browsing-context
+  readonly attribute boolean isInitialDocument;
+
+  readonly attribute FrameLoader? rootFrameLoader; // Embedded (browser) only
+
+  readonly attribute WindowGlobalChild? childActor; // in-process only
+
+  // Checks for any WindowContexts with "beforeunload" listeners in this
+  // WindowGlobal's subtree. If any exist, a "beforeunload" event is
+  // dispatched to them. If any of those request to block the navigation,
+  // displays a prompt to the user. Returns a boolean which resolves to true
+  // if the navigation should be allowed.
+  //
+  // If `timeout` is greater than 0, it is the maximum time (in milliseconds)
+  // we will wait for a child process to respond with a request to block
+  // navigation before proceeding. If the user needs to be prompted, however,
+  // the promise will not resolve until the user has responded, regardless of
+  // the timeout.
+  [NewObject]
+  Promise<boolean> permitUnload(optional PermitUnloadAction action = "prompt",
+                                optional unsigned long timeout = 0);
+
+  // Information about the currently loaded document.
+  readonly attribute Principal documentPrincipal;
+  readonly attribute Principal documentStoragePrincipal;
+  readonly attribute Principal? contentBlockingAllowListPrincipal;
+  readonly attribute URI? documentURI;
+  readonly attribute DOMString documentTitle;
+  readonly attribute nsICookieJarSettings? cookieJarSettings;
+
+  // True if the the currently loaded document is in fullscreen.
+  attribute boolean fullscreen;
+
+  // Bit mask containing content blocking events that are recorded in
+  // the document's content blocking log.
+  readonly attribute unsigned long contentBlockingEvents;
+
+  // String containing serialized content blocking log.
+  readonly attribute DOMString contentBlockingLog;
+
+  // DOM Process which this window was loaded in. Will be either InProcessParent
+  // for windows loaded in the parent process, or ContentParent for windows
+  // loaded in the content process.
+  readonly attribute nsIDOMProcessParent? domProcess;
+
+  static WindowGlobalParent? getByInnerWindowId(unsigned long long innerWindowId);
+
+  /**
+   * Get or create the JSWindowActor with the given name.
+   *
+   * See WindowActorOptions from JSWindowActor.webidl for details on how to
+   * customize actor creation.
+   */
+  [Throws]
+  JSWindowActorParent getActor(UTF8String name);
+  JSWindowActorParent? getExistingActor(UTF8String name);
+
+  /**
+   * Renders a region of the frame into an image bitmap.
+   *
+   * @param rect Specify the area of the document to render, in CSS pixels,
+   * relative to the page. If null, the currently visible viewport is rendered.
+   * @param scale The scale to render the window at. Use devicePixelRatio
+   * to have comparable rendering to the OS.
+   * @param backgroundColor The background color to use.
+   * @param resetScrollPosition If true, temporarily resets the scroll position
+   * of the root scroll frame to 0, such that position:fixed elements are drawn
+   * at their initial position. This parameter only takes effect when passing a
+   * non-null rect.
+   *
+   * This API can only be used in the parent process, as content processes
+   * cannot access the rendering of out of process iframes. This API works
+   * with remote and local frames.
+   */
+  [NewObject]
+  Promise<ImageBitmap> drawSnapshot(DOMRect? rect,
+                                    double scale,
+                                    UTF8String backgroundColor,
+                                    optional boolean resetScrollPosition = false);
+
+  // True if any of the windows in the subtree rooted at this window
+  // has active peer connections.  If this is called for a non-top-level
+  // context, it always returns false.
+  boolean hasActivePeerConnections();
+};
+
+[Exposed=Window, ChromeOnly]
+interface WindowGlobalChild {
+  readonly attribute boolean isClosed;
+  readonly attribute boolean isInProcess;
+  readonly attribute BrowsingContext browsingContext;
+  readonly attribute WindowContext windowContext;
+
+  readonly attribute boolean isCurrentGlobal;
+
+  readonly attribute unsigned long long innerWindowId;
+  readonly attribute unsigned long long outerWindowId;
+  readonly attribute unsigned long long contentParentId;
+
+  // A WindowGlobalChild is the root in its process if it has no parent, or its
+  // embedder is in a different process.
+  readonly attribute boolean isProcessRoot;
+
+  // Is this WindowGlobalChild same-origin with `window.top`?
+  readonly attribute boolean sameOriginWithTop;
+
+  readonly attribute WindowGlobalParent? parentActor; // in-process only
+
+  static WindowGlobalChild? getByInnerWindowId(unsigned long long innerWIndowId);
+
+  /**
+   * Get or create the JSWindowActor with the given name.
+   *
+   * See WindowActorOptions from JSWindowActor.webidl for details on how to
+   * customize actor creation.
+   */
+  [Throws]
+  JSWindowActorChild getActor(UTF8String name);
+  JSWindowActorChild? getExistingActor(UTF8String name);
+};
diff --git a/dom/chrome-webidl/XULFrameElement.webidl b/dom/chrome-webidl/XULFrameElement.webidl
new file mode 100644
index 0000000000..53be81a04a
--- /dev/null
+++ b/dom/chrome-webidl/XULFrameElement.webidl
@@ -0,0 +1,31 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+interface nsIDocShell;
+interface nsIWebNavigation;
+interface nsIOpenWindowInfo;
+
+[ChromeOnly,
+ Exposed=Window]
+interface XULFrameElement : XULElement
+{
+  [HTMLConstructor] constructor();
+
+  readonly attribute nsIDocShell? docShell;
+  readonly attribute nsIWebNavigation? webNavigation;
+
+  readonly attribute WindowProxy? contentWindow;
+  readonly attribute Document? contentDocument;
+
+  readonly attribute unsigned long long browserId;
+
+  /**
+   * The optional open window information provided by the window creation code
+   * and used to initialize a new browser.
+   */
+  attribute nsIOpenWindowInfo? openWindowInfo;
+};
+
+XULFrameElement includes MozFrameLoaderOwner;
diff --git a/dom/chrome-webidl/XULMenuElement.webidl b/dom/chrome-webidl/XULMenuElement.webidl
new file mode 100644
index 0000000000..3959c810ba
--- /dev/null
+++ b/dom/chrome-webidl/XULMenuElement.webidl
@@ -0,0 +1,19 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+[ChromeOnly,
+ Exposed=Window]
+interface XULMenuElement : XULElement {
+  [HTMLConstructor] constructor();
+
+  [BinaryName="activeMenuChild"]
+  attribute Element? activeChild;
+
+  boolean handleKeyPress(KeyboardEvent keyEvent);
+
+  readonly attribute boolean openedWithKey;
+
+};
diff --git a/dom/chrome-webidl/XULTextElement.webidl b/dom/chrome-webidl/XULTextElement.webidl
new file mode 100644
index 0000000000..6d75ca8602
--- /dev/null
+++ b/dom/chrome-webidl/XULTextElement.webidl
@@ -0,0 +1,15 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+[ChromeOnly,
+ Exposed=Window]
+interface XULTextElement : XULElement {
+  [HTMLConstructor] constructor();
+
+  attribute boolean disabled;
+  attribute DOMString value;
+  attribute DOMString accessKey;
+};
diff --git a/dom/chrome-webidl/XULTreeElement.webidl b/dom/chrome-webidl/XULTreeElement.webidl
new file mode 100644
index 0000000000..df9dc6a0f9
--- /dev/null
+++ b/dom/chrome-webidl/XULTreeElement.webidl
@@ -0,0 +1,180 @@
+
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+interface MozTreeView;
+
+dictionary TreeCellInfo {
+    long row = 0;
+    TreeColumn? col = null;
+    DOMString childElt = "";
+};
+
+[ChromeOnly,
+ Exposed=Window]
+interface XULTreeElement : XULElement
+{
+  [HTMLConstructor] constructor();
+
+  /**
+   * Obtain the columns.
+   */
+  readonly attribute TreeColumns? columns;
+
+  /**
+   * The view that backs the tree and that supplies it with its data.
+   * It is dynamically settable, either using a view attribute on the
+   * tree tag or by setting this attribute to a new value.
+   */
+  [SetterThrows, NeedsCallerType]
+  attribute MozTreeView? view;
+
+  /**
+   * Whether or not we are currently focused.
+   */
+  attribute boolean focused;
+
+  /**
+   * Obtain the treebody content node
+   */
+  readonly attribute Element? treeBody;
+
+  /**
+   * Obtain the height of a row.
+   */
+  readonly attribute long rowHeight;
+
+  /**
+   * Obtain the width of a row.
+   */
+  readonly attribute long rowWidth;
+
+  /**
+   * Get the pixel position of the horizontal scrollbar.
+   */
+  readonly attribute long horizontalPosition;
+
+  /**
+   * Get the index of the first visible row.
+   */
+  long getFirstVisibleRow();
+
+  /**
+   * Get the index of the last visible row.
+   */
+  long getLastVisibleRow();
+
+  /**
+   * Gets the number of possible visible rows.
+   */
+  long getPageLength();
+
+  /**
+   * Ensures that a row at a given index is visible.
+   */
+  undefined ensureRowIsVisible(long index);
+
+  /**
+   * Ensures that a given cell in the tree is visible.
+   */
+  [Throws]
+  undefined ensureCellIsVisible(long row, TreeColumn? col);
+
+  /**
+   * Scrolls such that the row at index is at the top of the visible view.
+   */
+  undefined scrollToRow(long index);
+
+  /**
+   * Scroll the tree up or down by numLines lines. Positive
+   * values move down in the tree. Prevents scrolling off the
+   * end of the tree.
+   */
+  undefined scrollByLines(long numLines);
+
+  /**
+   * Scroll the tree up or down by numPages pages. A page
+   * is considered to be the amount displayed by the tree.
+   * Positive values move down in the tree. Prevents scrolling
+   * off the end of the tree.
+   */
+  undefined scrollByPages(long numPages);
+
+  /**
+   * Invalidation methods for fine-grained painting control.
+   */
+  undefined invalidate();
+  undefined invalidateColumn(TreeColumn? col);
+  undefined invalidateRow(long index);
+  undefined invalidateCell(long row, TreeColumn? col);
+  undefined invalidateRange(long startIndex, long endIndex);
+
+  /**
+   * A hit test that can tell you what row the mouse is over.
+   * returns -1 for invalid mouse coordinates.
+   *
+   * The coordinate system is the client coordinate system for the
+   * document this tree lives in, and the units are CSS pixels.
+   */
+  long getRowAt(long x, long y);
+
+  /**
+   * A hit test that can tell you what cell the mouse is over.
+   * TreeCellInfo.row is the row index hit,  returns -1 for invalid mouse
+   * coordinates.  TreeCellInfo.col is the column hit.
+   * TreeCellInfo.childElt is the pseudoelement hit: this can have values of
+   * "cell", "twisty", "image", and "text".
+   *
+   * The coordinate system is the client coordinate system for the
+   * document this tree lives in, and the units are CSS pixels.
+   */
+  [Throws]
+  TreeCellInfo getCellAt(long x, long y);
+
+  /**
+   * Find the coordinates of an element within a specific cell.
+   */
+  [Throws]
+  DOMRect? getCoordsForCellItem(long row, TreeColumn col, DOMString element);
+
+  /**
+   * Determine if the text of a cell is being cropped or not.
+   */
+  [Throws]
+  boolean isCellCropped(long row, TreeColumn? col);
+
+  /**
+   * The view is responsible for calling these notification methods when
+   * rows are added or removed.  Index is the position at which the new
+   * rows were added or at which rows were removed.  For
+   * non-contiguous additions/removals, this method should be called multiple times.
+   */
+  undefined rowCountChanged(long index, long count);
+
+  /**
+   * Notify the tree that the view is about to perform a batch
+   * update, that is, add, remove or invalidate several rows at once.
+   * This must be followed by calling endUpdateBatch(), otherwise the tree
+   * will get out of sync.
+   */
+  undefined beginUpdateBatch();
+
+  /**
+   * Notify the tree that the view has completed a batch update.
+   */
+  undefined endUpdateBatch();
+
+  /**
+   * Called on a theme switch to flush out the tree's style and image caches.
+   */
+  undefined clearStyleAndImageCaches();
+
+  /**
+   * Remove an image source from the image cache to allow its invalidation.
+   */
+  [Throws]
+  undefined removeImageCacheEntry(long row, TreeColumn col);
+};
diff --git a/dom/chrome-webidl/moz.build b/dom/chrome-webidl/moz.build
new file mode 100644
index 0000000000..ef2da6b22a
--- /dev/null
+++ b/dom/chrome-webidl/moz.build
@@ -0,0 +1,112 @@
+# -*- 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 = ("Core", "DOM: Core & HTML")
+
+with Files("ChannelWrapper.webidl"):
+    BUG_COMPONENT = ("WebExtensions", "Request Handling")
+
+with Files("Flex.webidl"):
+    BUG_COMPONENT = ("Core", "CSS Parsing and Computation")
+
+with Files("HeapSnapshot.webidl"):
+    BUG_COMPONENT = ("DevTools", "Memory")
+
+with Files("InspectorUtils.webidl"):
+    BUG_COMPONENT = ("DevTools", "Inspector")
+
+with Files("MatchGlob.webidl"):
+    BUG_COMPONENT = ("WebExtensions", "General")
+
+with Files("MatchPattern.webidl"):
+    BUG_COMPONENT = ("WebExtensions", "General")
+
+with Files("WebExtension*.webidl"):
+    BUG_COMPONENT = ("WebExtensions", "General")
+
+with Files("Glean*.webidl"):
+    BUG_COMPONENT = ("Toolkit", "Telemetry")
+
+with Files("IOUtils.webidl"):
+    BUG_COMPONENT = ("Toolkit", "OS.File")
+
+with Files("PathUtils.webidl"):
+    BUG_COMPONENT = ("Toolkit", "OS.File")
+
+PREPROCESSED_WEBIDL_FILES = [
+    "ChromeUtils.webidl",
+    "IOUtils.webidl",
+]
+
+WEBIDL_FILES = [
+    "BrowserSessionStore.webidl",
+    "BrowsingContext.webidl",
+    "ChannelWrapper.webidl",
+    "ClonedErrorHolder.webidl",
+    "DebuggerNotification.webidl",
+    "DebuggerNotificationObserver.webidl",
+    "DebuggerUtils.webidl",
+    "DocumentL10n.webidl",
+    "DOMCollectedFrames.webidl",
+    "DominatorTree.webidl",
+    "Flex.webidl",
+    "Fluent.webidl",
+    "FrameLoader.webidl",
+    "HeapSnapshot.webidl",
+    "ImageText.webidl",
+    "InspectorUtils.webidl",
+    "IteratorResult.webidl",
+    "JSActor.webidl",
+    "JSProcessActor.webidl",
+    "JSWindowActor.webidl",
+    "L10nOverlays.webidl",
+    "L10nRegistry.webidl",
+    "MatchGlob.webidl",
+    "MatchPattern.webidl",
+    "MediaController.webidl",
+    "MessageManager.webidl",
+    "MozDocumentObserver.webidl",
+    "MozSharedMap.webidl",
+    "MozStorageAsyncStatementParams.webidl",
+    "MozStorageStatementParams.webidl",
+    "MozStorageStatementRow.webidl",
+    "NetDashboard.webidl",
+    "PathUtils.webidl",
+    "PrecompiledScript.webidl",
+    "PromiseDebugging.webidl",
+    "SessionStoreUtils.webidl",
+    "StructuredCloneHolder.webidl",
+    "TelemetryStopwatch.webidl",
+    "UserInteraction.webidl",
+    "WebExtensionContentScript.webidl",
+    "WebExtensionPolicy.webidl",
+    "WindowGlobalActors.webidl",
+    "XULFrameElement.webidl",
+    "XULMenuElement.webidl",
+    "XULTextElement.webidl",
+    "XULTreeElement.webidl",
+]
+
+if CONFIG["MOZ_BUILD_APP"] != "mobile/android":
+    WEBIDL_FILES += [
+        "UniFFI.webidl",
+    ]
+
+if CONFIG["MOZ_PLACES"]:
+    WEBIDL_FILES += [
+        "PlacesEvent.webidl",
+        "PlacesObservers.webidl",
+    ]
+
+WEBIDL_FILES += [
+    "Glean.webidl",
+    "GleanPings.webidl",
+]
+
+WEBIDL_FILES += [
+    "PrioEncoder.webidl",
+]