From c5353a7809676163451349afa434ad221d2ea3b6 Mon Sep 17 00:00:00 2001
From: Kris Maglione <maglione.k@gmail.com>
Date: Wed, 29 Apr 2020 19:29:06 +0000
Subject: [PATCH] Bug 1630691: Part 1 - Get rid of most of the remaining
 mozbrowser API. r=nika,mtigley,bradwerth

Differential Revision: https://phabricator.services.mozilla.com/D71226
---
 dom/base/FragmentOrElement.cpp                |    6 -
 dom/base/nsContentUtils.cpp                   |   21 -
 dom/base/nsContentUtils.h                     |    9 -
 dom/base/nsFocusManager.cpp                   |   49 +-
 dom/base/nsFrameLoader.cpp                    |   20 +-
 dom/browser-element/BrowserElementChild.js    |   39 -
 .../BrowserElementChildPreload.js             | 1069 +----------------
 .../BrowserElementCopyPaste.js                |  138 ---
 dom/browser-element/BrowserElementParent.jsm  |  389 +-----
 dom/events/EventStateManager.cpp              |    4 -
 dom/html/nsBrowserElement.cpp                 |   83 --
 dom/ipc/jar.mn                                |    1 -
 dom/webidl/BrowserElement.webidl              |   47 -
 dom/webidl/HTMLIFrameElement.webidl           |    7 -
 dom/webidl/moz.build                          |    4 -
 15 files changed, 30 insertions(+), 1856 deletions(-)
 delete mode 100644 dom/browser-element/BrowserElementCopyPaste.js
 delete mode 100644 dom/webidl/BrowserElement.webidl

diff --git a/dom/base/FragmentOrElement.cpp b/dom/base/FragmentOrElement.cpp
index 52579805549a..c0ce8d087b7c 100644
--- a/dom/base/FragmentOrElement.cpp
+++ b/dom/base/FragmentOrElement.cpp
@@ -1019,12 +1019,6 @@ bool nsIContent::IsFocusable(int32_t* aTabIndex, bool aWithMouse) {
   // Ensure that the return value and aTabIndex are consistent in the case
   // we're in userfocusignored context.
   if (focusable || (aTabIndex && *aTabIndex != -1)) {
-    if (nsContentUtils::IsUserFocusIgnored(this)) {
-      if (aTabIndex) {
-        *aTabIndex = -1;
-      }
-      return false;
-    }
     return focusable;
   }
   return false;
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 93d6d24ef8ac..281baecee2b8 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -6181,27 +6181,6 @@ bool nsContentUtils::IsSubDocumentTabbable(nsIContent* aContent) {
   return true;
 }
 
-bool nsContentUtils::IsUserFocusIgnored(nsINode* aNode) {
-  if (!StaticPrefs::dom_mozBrowserFramesEnabled()) {
-    return false;
-  }
-
-  // Check if our mozbrowser iframe ancestors has ignoreuserfocus attribute.
-  while (aNode) {
-    nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(aNode);
-    if (browserFrame &&
-        aNode->AsElement()->HasAttr(kNameSpaceID_None,
-                                    nsGkAtoms::ignoreuserfocus) &&
-        browserFrame->GetReallyIsBrowser()) {
-      return true;
-    }
-    nsPIDOMWindowOuter* win = aNode->OwnerDoc()->GetWindow();
-    aNode = win ? win->GetFrameElementInternal() : nullptr;
-  }
-
-  return false;
-}
-
 bool nsContentUtils::HasScrollgrab(nsIContent* aContent) {
   // If we ever standardize this feature we'll want to hook this up properly
   // again. For now we're removing all the DOM-side code related to it but
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index 237344ebfebc..c81cc6a69d74 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2483,15 +2483,6 @@ class nsContentUtils {
    */
   static bool IsSubDocumentTabbable(nsIContent* aContent);
 
-  /**
-   * Returns if aNode ignores user focus.
-   *
-   * @param aNode node to test
-   *
-   * @return Whether the node ignores user focus.
-   */
-  static bool IsUserFocusIgnored(nsINode* aNode);
-
   /**
    * Returns if aContent has the 'scrollgrab' property.
    * aContent may be null (in this case false is returned).
diff --git a/dom/base/nsFocusManager.cpp b/dom/base/nsFocusManager.cpp
index 4eaaad5032e8..99deaa270cd1 100644
--- a/dom/base/nsFocusManager.cpp
+++ b/dom/base/nsFocusManager.cpp
@@ -1785,8 +1785,7 @@ bool nsFocusManager::IsNonFocusableRoot(nsIContent* aContent) {
   Document* doc = aContent->GetComposedDoc();
   NS_ASSERTION(doc, "aContent must have current document");
   return aContent == doc->GetRootElement() &&
-         (doc->HasFlag(NODE_IS_EDITABLE) || !aContent->IsEditable() ||
-          nsContentUtils::IsUserFocusIgnored(aContent));
+         (doc->HasFlag(NODE_IS_EDITABLE) || !aContent->IsEditable());
 }
 
 Element* nsFocusManager::FlushAndCheckIfFocusable(Element* aElement,
@@ -1819,7 +1818,7 @@ Element* nsFocusManager::FlushAndCheckIfFocusable(Element* aElement,
   // the root content can always be focused,
   // except in userfocusignored context.
   if (aElement == doc->GetRootElement()) {
-    return nsContentUtils::IsUserFocusIgnored(aElement) ? nullptr : aElement;
+    return aElement;
   }
 
   // cannot focus content in print preview mode. Only the root can be focused.
@@ -2514,10 +2513,7 @@ void nsFocusManager::SendFocusOrBlurEvent(
     aRelatedTarget = nullptr;
   }
 
-  bool dontDispatchEvent =
-      eventTargetDoc && nsContentUtils::IsUserFocusIgnored(eventTargetDoc);
-
-  if (!dontDispatchEvent && aDocument && aDocument->EventHandlingSuppressed()) {
+  if (aDocument && aDocument->EventHandlingSuppressed()) {
     for (uint32_t i = mDelayedBlurFocusEvents.Length(); i > 0; --i) {
       // if this event was already queued, remove it and append it to the end
       if (mDelayedBlurFocusEvents[i - 1].mEventMessage == aEventMessage &&
@@ -2550,17 +2546,12 @@ void nsFocusManager::FireFocusOrBlurEvent(EventMessage aEventMessage,
                                           nsISupports* aTarget,
                                           bool aWindowRaised, bool aIsRefocus,
                                           EventTarget* aRelatedTarget) {
-  nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(aTarget);
-  nsCOMPtr<Document> eventTargetDoc = GetDocumentHelper(eventTarget);
   nsCOMPtr<nsPIDOMWindowOuter> currentWindow = mFocusedWindow;
   nsCOMPtr<nsPIDOMWindowInner> targetWindow = do_QueryInterface(aTarget);
   nsCOMPtr<Document> targetDocument = do_QueryInterface(aTarget);
   nsCOMPtr<nsIContent> currentFocusedContent =
       currentWindow ? currentWindow->GetFocusedElement() : nullptr;
 
-  bool dontDispatchEvent =
-      eventTargetDoc && nsContentUtils::IsUserFocusIgnored(eventTargetDoc);
-
 #ifdef ACCESSIBILITY
   nsAccessibilityService* accService = GetAccService();
   if (accService) {
@@ -2572,25 +2563,23 @@ void nsFocusManager::FireFocusOrBlurEvent(EventMessage aEventMessage,
   }
 #endif
 
-  if (!dontDispatchEvent) {
-    nsContentUtils::AddScriptRunner(
-        new FocusBlurEvent(aTarget, aEventMessage, aPresShell->GetPresContext(),
-                           aWindowRaised, aIsRefocus, aRelatedTarget));
+  nsContentUtils::AddScriptRunner(
+      new FocusBlurEvent(aTarget, aEventMessage, aPresShell->GetPresContext(),
+                         aWindowRaised, aIsRefocus, aRelatedTarget));
 
-    // Check that the target is not a window or document before firing
-    // focusin/focusout. Other browsers do not fire focusin/focusout on window,
-    // despite being required in the spec, so follow their behavior.
-    //
-    // As for document, we should not even fire focus/blur, but until then, we
-    // need this check. targetDocument should be removed once bug 1228802 is
-    // resolved.
-    if (!targetWindow && !targetDocument) {
-      EventMessage focusInOrOutMessage =
-          aEventMessage == eFocus ? eFocusIn : eFocusOut;
-      FireFocusInOrOutEvent(focusInOrOutMessage, aPresShell, aTarget,
-                            currentWindow, currentFocusedContent,
-                            aRelatedTarget);
-    }
+  // Check that the target is not a window or document before firing
+  // focusin/focusout. Other browsers do not fire focusin/focusout on window,
+  // despite being required in the spec, so follow their behavior.
+  //
+  // As for document, we should not even fire focus/blur, but until then, we
+  // need this check. targetDocument should be removed once bug 1228802 is
+  // resolved.
+  if (!targetWindow && !targetDocument) {
+    EventMessage focusInOrOutMessage =
+        aEventMessage == eFocus ? eFocusIn : eFocusOut;
+    FireFocusInOrOutEvent(focusInOrOutMessage, aPresShell, aTarget,
+                          currentWindow, currentFocusedContent,
+                          aRelatedTarget);
   }
 }
 
diff --git a/dom/base/nsFrameLoader.cpp b/dom/base/nsFrameLoader.cpp
index 1588865c503d..2f8c00aaa799 100644
--- a/dom/base/nsFrameLoader.cpp
+++ b/dom/base/nsFrameLoader.cpp
@@ -3174,18 +3174,16 @@ void nsFrameLoader::InitializeBrowserAPI() {
   if (!OwnerIsMozBrowserFrame()) {
     return;
   }
-  if (!IsRemoteFrame()) {
-    nsresult rv = EnsureMessageManager();
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return;
-    }
-    if (mMessageManager) {
-      mMessageManager->LoadFrameScript(
-          NS_LITERAL_STRING("chrome://global/content/BrowserElementChild.js"),
-          /* allowDelayedLoad = */ true,
-          /* aRunInGlobalScope */ true, IgnoreErrors());
-    }
+
+  nsresult rv = EnsureMessageManager();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
   }
+  mMessageManager->LoadFrameScript(
+      NS_LITERAL_STRING("chrome://global/content/BrowserElementChild.js"),
+      /* allowDelayedLoad = */ true,
+      /* aRunInGlobalScope */ true, IgnoreErrors());
+
   nsCOMPtr<nsIMozBrowserFrame> browserFrame = do_QueryInterface(mOwnerContent);
   if (browserFrame) {
     browserFrame->InitializeBrowserAPI();
diff --git a/dom/browser-element/BrowserElementChild.js b/dom/browser-element/BrowserElementChild.js
index 80e968c724b0..5522175535e8 100644
--- a/dom/browser-element/BrowserElementChild.js
+++ b/dom/browser-element/BrowserElementChild.js
@@ -17,48 +17,12 @@ function debug(msg) {
 // mozbrowser API clients.
 docShell.isActive = true;
 
-function parentDocShell(docshell) {
-  if (!docshell) {
-    return null;
-  }
-  let treeitem = docshell.QueryInterface(Ci.nsIDocShellTreeItem);
-  return treeitem.parent
-    ? treeitem.parent.QueryInterface(Ci.nsIDocShell)
-    : null;
-}
-
-function isTopBrowserElement(docShell) {
-  while (docShell) {
-    docShell = parentDocShell(docShell);
-    if (docShell && docShell.isMozBrowser) {
-      return false;
-    }
-  }
-  return true;
-}
-
 var BrowserElementIsReady;
 
 debug(`Might load BE scripts: BEIR: ${BrowserElementIsReady}`);
 if (!BrowserElementIsReady) {
   debug("Loading BE scripts");
   if (!("BrowserElementIsPreloaded" in this)) {
-    if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_CONTENT) {
-      // general content apps
-      if (isTopBrowserElement(docShell)) {
-        Services.scriptloader.loadSubScript(
-          "chrome://global/content/BrowserElementCopyPaste.js",
-          this
-        );
-      }
-    } else {
-      // rocketbar in system app and other in-process case (ex. B2G desktop client)
-      Services.scriptloader.loadSubScript(
-        "chrome://global/content/BrowserElementCopyPaste.js",
-        this
-      );
-    }
-
     Services.scriptloader.loadSubScript(
       "chrome://global/content/BrowserElementChildPreload.js",
       this
@@ -71,9 +35,6 @@ if (!BrowserElementIsReady) {
     if (api) {
       api.destroy();
     }
-    if ("CopyPasteAssistent" in this) {
-      CopyPasteAssistent.destroy();
-    }
 
     BrowserElementIsReady = false;
   }
diff --git a/dom/browser-element/BrowserElementChildPreload.js b/dom/browser-element/BrowserElementChildPreload.js
index 3313eb782b89..bc6cc1d9bb57 100644
--- a/dom/browser-element/BrowserElementChildPreload.js
+++ b/dom/browser-element/BrowserElementChildPreload.js
@@ -19,14 +19,6 @@ var { BrowserElementPromptService } = ChromeUtils.import(
   "resource://gre/modules/BrowserElementPromptService.jsm"
 );
 
-var kLongestReturnedString = 128;
-
-var Timer = Components.Constructor(
-  "@mozilla.org/timer;1",
-  "nsITimer",
-  "initWithCallback"
-);
-
 function sendAsyncMsg(msg, data) {
   // Ensure that we don't send any messages before BrowserElementChild.js
   // finishes loading.
@@ -42,46 +34,7 @@ function sendAsyncMsg(msg, data) {
   sendAsyncMessage("browser-element-api:call", data);
 }
 
-function sendSyncMsg(msg, data) {
-  // Ensure that we don't send any messages before BrowserElementChild.js
-  // finishes loading.
-  if (!BrowserElementIsReady) {
-    return undefined;
-  }
-
-  if (!data) {
-    data = {};
-  }
-
-  data.msg_name = msg;
-  return sendSyncMessage("browser-element-api:call", data);
-}
-
-var CERTIFICATE_ERROR_PAGE_PREF = "security.alternate_certificate_error_page";
-
-var OBSERVED_EVENTS = [
-  "xpcom-shutdown",
-  "audio-playback",
-  "activity-done",
-  "will-launch-app",
-];
-
 var LISTENED_EVENTS = [
-  { type: "DOMTitleChanged", useCapture: true, wantsUntrusted: false },
-  { type: "DOMLinkAdded", useCapture: true, wantsUntrusted: false },
-  { type: "MozScrolledAreaChanged", useCapture: true, wantsUntrusted: false },
-  { type: "MozDOMFullscreen:Request", useCapture: true, wantsUntrusted: false },
-  {
-    type: "MozDOMFullscreen:NewOrigin",
-    useCapture: true,
-    wantsUntrusted: false,
-  },
-  { type: "MozDOMFullscreen:Exit", useCapture: true, wantsUntrusted: false },
-  { type: "DOMMetaAdded", useCapture: true, wantsUntrusted: false },
-  { type: "DOMMetaChanged", useCapture: true, wantsUntrusted: false },
-  { type: "DOMMetaRemoved", useCapture: true, wantsUntrusted: false },
-  { type: "scrollviewchange", useCapture: true, wantsUntrusted: false },
-  { type: "click", useCapture: false, wantsUntrusted: false },
   // This listens to unload events from our message manager, but /not/ from
   // the |content| window.  That's because the window's unload event doesn't
   // bubble, and we're not using a capturing listener.  If we'd used
@@ -90,16 +43,6 @@ var LISTENED_EVENTS = [
   { type: "unload", useCapture: false, wantsUntrusted: false },
 ];
 
-// We are using the system group for those events so if something in the
-// content called .stopPropagation() this will still be called.
-var LISTENED_SYSTEM_EVENTS = [
-  { type: "DOMWindowClose", useCapture: false },
-  { type: "DOMWindowCreated", useCapture: false },
-  { type: "DOMWindowResize", useCapture: false },
-  { type: "contextmenu", useCapture: false },
-  { type: "scroll", useCapture: false },
-];
-
 /**
  * The BrowserElementChild implements one half of <iframe mozbrowser>.
  * (The other half is, unsurprisingly, BrowserElementParent.)
@@ -117,51 +60,15 @@ function BrowserElementChild() {
   // Maps outer window id --> weak ref to window.  Used by modal dialog code.
   this._windowIDDict = {};
 
-  this._isContentWindowCreated = false;
-
   this._init();
 }
 
 BrowserElementChild.prototype = {
-  QueryInterface: ChromeUtils.generateQI([
-    Ci.nsIObserver,
-    Ci.nsISupportsWeakReference,
-  ]),
-
   _init() {
     debug("Starting up.");
 
     BrowserElementPromptService.mapWindowToBrowserElementChild(content, this);
 
-    docShell
-      .QueryInterface(Ci.nsIWebProgress)
-      .addProgressListener(
-        this._progressListener,
-        Ci.nsIWebProgress.NOTIFY_LOCATION |
-          Ci.nsIWebProgress.NOTIFY_SECURITY |
-          Ci.nsIWebProgress.NOTIFY_STATE_WINDOW
-      );
-
-    let webNavigation = docShell.QueryInterface(Ci.nsIWebNavigation);
-    if (!webNavigation.sessionHistory) {
-      // XXX(nika): I don't think this code should ever be hit? We should run
-      // BrowserChild::Init before we run this code which will perform this setup
-      // for us.
-      docShell.initSessionHistory();
-    }
-
-    // This is necessary to get security web progress notifications.
-    var securityUI = Cc["@mozilla.org/secure_browser_ui;1"].createInstance(
-      Ci.nsISecureBrowserUI
-    );
-    securityUI.init(docShell);
-
-    // A cache of the menuitem dom objects keyed by the id we generate
-    // and pass to the embedder
-    this._ctxHandlers = {};
-    // Counter of contextmenu events fired
-    this._ctxCounter = 0;
-
     this._shuttingDown = false;
 
     LISTENED_EVENTS.forEach(event => {
@@ -173,25 +80,7 @@ BrowserElementChild.prototype = {
       );
     });
 
-    // Registers a MozAfterPaint handler for the very first paint.
-    this._addMozAfterPaintHandler(function() {
-      sendAsyncMsg("firstpaint");
-    });
-
     addMessageListener("browser-element-api:call", this);
-
-    LISTENED_SYSTEM_EVENTS.forEach(event => {
-      Services.els.addSystemEventListener(
-        global,
-        event.type,
-        this,
-        event.useCapture
-      );
-    });
-
-    OBSERVED_EVENTS.forEach(aTopic => {
-      Services.obs.addObserver(this, aTopic);
-    });
   },
 
   /**
@@ -206,10 +95,6 @@ BrowserElementChild.prototype = {
 
     BrowserElementPromptService.unmapWindowToBrowserElementChild(content);
 
-    docShell
-      .QueryInterface(Ci.nsIWebProgress)
-      .removeProgressListener(this._progressListener);
-
     LISTENED_EVENTS.forEach(event => {
       removeEventListener(
         event.type,
@@ -220,74 +105,13 @@ BrowserElementChild.prototype = {
     });
 
     removeMessageListener("browser-element-api:call", this);
-
-    LISTENED_SYSTEM_EVENTS.forEach(event => {
-      Services.els.removeSystemEventListener(
-        global,
-        event.type,
-        this,
-        event.useCapture
-      );
-    });
-
-    OBSERVED_EVENTS.forEach(aTopic => {
-      Services.obs.removeObserver(this, aTopic);
-    });
   },
 
   handleEvent(event) {
     switch (event.type) {
-      case "DOMTitleChanged":
-        this._titleChangedHandler(event);
-        break;
-      case "DOMLinkAdded":
-        this._linkAddedHandler(event);
-        break;
-      case "MozScrolledAreaChanged":
-        this._mozScrollAreaChanged(event);
-        break;
-      case "MozDOMFullscreen:Request":
-        this._mozRequestedDOMFullscreen(event);
-        break;
-      case "MozDOMFullscreen:NewOrigin":
-        this._mozFullscreenOriginChange(event);
-        break;
-      case "MozDOMFullscreen:Exit":
-        this._mozExitDomFullscreen(event);
-        break;
-      case "DOMMetaAdded":
-        this._metaChangedHandler(event);
-        break;
-      case "DOMMetaChanged":
-        this._metaChangedHandler(event);
-        break;
-      case "DOMMetaRemoved":
-        this._metaChangedHandler(event);
-        break;
-      case "scrollviewchange":
-        this._ScrollViewChangeHandler(event);
-        break;
-      case "click":
-        this._ClickHandler(event);
-        break;
       case "unload":
         this.destroy(event);
         break;
-      case "DOMWindowClose":
-        this._windowCloseHandler(event);
-        break;
-      case "DOMWindowCreated":
-        this._windowCreatedHandler(event);
-        break;
-      case "DOMWindowResize":
-        this._windowResizeHandler(event);
-        break;
-      case "contextmenu":
-        this._contextmenuHandler(event);
-        break;
-      case "scroll":
-        this._scrollEventHandler(event);
-        break;
     }
   },
 
@@ -295,19 +119,8 @@ BrowserElementChild.prototype = {
     let self = this;
 
     let mmCalls = {
-      "send-mouse-event": this._recvSendMouseEvent,
-      "get-can-go-back": this._recvCanGoBack,
-      "get-can-go-forward": this._recvCanGoForward,
-      "go-back": this._recvGoBack,
-      "go-forward": this._recvGoForward,
-      reload: this._recvReload,
-      stop: this._recvStop,
-      zoom: this._recvZoom,
       "unblock-modal-prompt": this._recvStopWaiting,
-      "fire-ctx-callback": this._recvFireCtxCallback,
       "owner-visibility-change": this._recvOwnerVisibilityChange,
-      "entered-fullscreen": this._recvEnteredFullscreen,
-      "exit-fullscreen": this._recvExitFullscreen,
     };
 
     if (message.data.msg_name in mmCalls) {
@@ -316,65 +129,6 @@ BrowserElementChild.prototype = {
     return undefined;
   },
 
-  _paintFrozenTimer: null,
-  observe(subject, topic, data) {
-    // Ignore notifications not about our document.  (Note that |content| /can/
-    // be null; see bug 874900.)
-
-    if (
-      topic !== "activity-done" &&
-      topic !== "audio-playback" &&
-      topic !== "will-launch-app" &&
-      (!content || subject !== content.document)
-    ) {
-      return;
-    }
-    if (topic == "activity-done" && docShell !== subject) {
-      return;
-    }
-    switch (topic) {
-      case "activity-done":
-        sendAsyncMsg("activitydone", { success: data == "activity-success" });
-        break;
-      case "audio-playback":
-        if (subject === content) {
-          sendAsyncMsg("audioplaybackchange", { _payload_: data });
-        }
-        break;
-      case "xpcom-shutdown":
-        this._shuttingDown = true;
-        break;
-      case "will-launch-app":
-        // If the launcher is not visible, let's ignore the message.
-        if (!docShell.isActive) {
-          return;
-        }
-
-        // If this is not a content process, let's not freeze painting.
-        if (
-          Services.appinfo.processType != Services.appinfo.PROCESS_TYPE_CONTENT
-        ) {
-          return;
-        }
-
-        docShell.contentViewer.pausePainting();
-
-        this._paintFrozenTimer && this._paintFrozenTimer.cancel();
-        this._paintFrozenTimer = new Timer(
-          this,
-          3000,
-          Ci.nsITimer.TYPE_ONE_SHOT
-        );
-        break;
-    }
-  },
-
-  notify(timer) {
-    docShell.contentViewer.resumePainting();
-    this._paintFrozenTimer.cancel();
-    this._paintFrozenTimer = null;
-  },
-
   get _windowUtils() {
     return content.document.defaultView.windowUtils;
   },
@@ -534,506 +288,6 @@ BrowserElementChild.prototype = {
     win.modalDepth--;
   },
 
-  _recvEnteredFullscreen() {
-    if (
-      !this._windowUtils.handleFullscreenRequests() &&
-      !content.document.fullscreenElement
-    ) {
-      // If we don't actually have any pending fullscreen request
-      // to handle, neither we have been in fullscreen, tell the
-      // parent to just exit.
-      sendAsyncMsg("exit-dom-fullscreen");
-    }
-  },
-
-  _recvExitFullscreen() {
-    this._windowUtils.exitFullscreen();
-  },
-
-  _titleChangedHandler(e) {
-    debug("Got titlechanged: (" + e.target.title + ")");
-    var win = e.target.defaultView;
-
-    // Ignore titlechanges which don't come from the top-level
-    // <iframe mozbrowser> window.
-    if (win == content) {
-      sendAsyncMsg("titlechange", { _payload_: e.target.title });
-    } else {
-      debug("Not top level!");
-    }
-  },
-
-  _maybeCopyAttribute(src, target, attribute) {
-    if (src.getAttribute(attribute)) {
-      target[attribute] = src.getAttribute(attribute);
-    }
-  },
-
-  _iconChangedHandler(e) {
-    debug("Got iconchanged: (" + e.target.href + ")");
-    let icon = { href: e.target.href };
-    this._maybeCopyAttribute(e.target, icon, "sizes");
-    this._maybeCopyAttribute(e.target, icon, "rel");
-    sendAsyncMsg("iconchange", icon);
-  },
-
-  _openSearchHandler(e) {
-    debug("Got opensearch: (" + e.target.href + ")");
-
-    if (e.target.type !== "application/opensearchdescription+xml") {
-      return;
-    }
-
-    sendAsyncMsg("opensearch", { title: e.target.title, href: e.target.href });
-  },
-
-  // Processes the "rel" field in <link> tags and forward to specific handlers.
-  _linkAddedHandler(e) {
-    let win = e.target.ownerGlobal;
-    // Ignore links which don't come from the top-level
-    // <iframe mozbrowser> window.
-    if (win != content) {
-      debug("Not top level!");
-      return;
-    }
-
-    let handlers = {
-      icon: this._iconChangedHandler.bind(this),
-      "apple-touch-icon": this._iconChangedHandler.bind(this),
-      "apple-touch-icon-precomposed": this._iconChangedHandler.bind(this),
-      search: this._openSearchHandler,
-    };
-
-    debug("Got linkAdded: (" + e.target.href + ") " + e.target.rel);
-    e.target.rel.split(" ").forEach(function(x) {
-      let token = x.toLowerCase();
-      if (handlers[token]) {
-        handlers[token](e);
-      }
-    }, this);
-  },
-
-  _metaChangedHandler(e) {
-    let win = e.target.ownerGlobal;
-    // Ignore metas which don't come from the top-level
-    // <iframe mozbrowser> window.
-    if (win != content) {
-      debug("Not top level!");
-      return;
-    }
-
-    var name = e.target.name;
-    var property = e.target.getAttributeNS(null, "property");
-
-    if (!name && !property) {
-      return;
-    }
-
-    debug("Got metaChanged: (" + (name || property) + ") " + e.target.content);
-
-    let handlers = {
-      viewmode: this._genericMetaHandler,
-      "theme-color": this._genericMetaHandler,
-      "theme-group": this._genericMetaHandler,
-      "application-name": this._applicationNameChangedHandler,
-    };
-    let handler = handlers[name];
-
-    if ((property || name).match(/^og:/)) {
-      name = property || name;
-      handler = this._genericMetaHandler;
-    }
-
-    if (handler) {
-      handler(name, e.type, e.target);
-    }
-  },
-
-  _applicationNameChangedHandler(name, eventType, target) {
-    if (eventType !== "DOMMetaAdded") {
-      // Bug 1037448 - Decide what to do when <meta name="application-name">
-      // changes
-      return;
-    }
-
-    let meta = { name, content: target.content };
-
-    let lang;
-    let elm;
-
-    for (
-      elm = target;
-      !lang && elm && elm.nodeType == target.ELEMENT_NODE;
-      elm = elm.parentNode
-    ) {
-      if (elm.hasAttribute("lang")) {
-        lang = elm.getAttribute("lang");
-        continue;
-      }
-
-      if (elm.hasAttributeNS("http://www.w3.org/XML/1998/namespace", "lang")) {
-        lang = elm.getAttributeNS(
-          "http://www.w3.org/XML/1998/namespace",
-          "lang"
-        );
-        continue;
-      }
-    }
-
-    // No lang has been detected.
-    if (!lang && elm.nodeType == target.DOCUMENT_NODE) {
-      lang = elm.contentLanguage;
-    }
-
-    if (lang) {
-      meta.lang = lang;
-    }
-
-    sendAsyncMsg("metachange", meta);
-  },
-
-  _ScrollViewChangeHandler(e) {
-    e.stopPropagation();
-    let detail = {
-      state: e.state,
-    };
-    sendAsyncMsg("scrollviewchange", detail);
-  },
-
-  _ClickHandler(e) {
-    let isHTMLLink = node =>
-      (ChromeUtils.getClassName(node) === "HTMLAnchorElement" && node.href) ||
-      (ChromeUtils.getClassName(node) === "HTMLAreaElement" && node.href) ||
-      ChromeUtils.getClassName(node) === "HTMLLinkElement";
-
-    // Open in a new tab if middle click or ctrl/cmd-click,
-    // and e.target is a link or inside a link.
-    if (
-      (Services.appinfo.OS == "Darwin" && e.metaKey) ||
-      (Services.appinfo.OS != "Darwin" && e.ctrlKey) ||
-      e.button == 1
-    ) {
-      let node = e.target;
-      while (node && !isHTMLLink(node)) {
-        node = node.parentNode;
-      }
-
-      if (node) {
-        sendAsyncMsg("opentab", { url: node.href });
-      }
-    }
-  },
-
-  _genericMetaHandler(name, eventType, target) {
-    let meta = {
-      name,
-      content: target.content,
-      type: eventType.replace("DOMMeta", "").toLowerCase(),
-    };
-    sendAsyncMsg("metachange", meta);
-  },
-
-  _addMozAfterPaintHandler(callback) {
-    function onMozAfterPaint() {
-      let uri = docShell.QueryInterface(Ci.nsIWebNavigation).currentURI;
-      if (uri.spec != "about:blank") {
-        debug("Got afterpaint event: " + uri.spec);
-        removeEventListener(
-          "MozAfterPaint",
-          onMozAfterPaint,
-          /* useCapture = */ true
-        );
-        callback();
-      }
-    }
-
-    addEventListener("MozAfterPaint", onMozAfterPaint, /* useCapture = */ true);
-    return onMozAfterPaint;
-  },
-
-  _windowCloseHandler(e) {
-    let win = e.target;
-    if (win != content || e.defaultPrevented) {
-      return;
-    }
-
-    debug("Closing window " + win);
-    sendAsyncMsg("close");
-
-    // Inform the window implementation that we handled this close ourselves.
-    e.preventDefault();
-  },
-
-  _windowCreatedHandler(e) {
-    let targetDocShell = e.target.defaultView.docShell;
-    if (targetDocShell != docShell) {
-      return;
-    }
-
-    let uri = docShell.QueryInterface(Ci.nsIWebNavigation).currentURI;
-    debug("Window created: " + uri.spec);
-    if (uri.spec != "about:blank") {
-      this._addMozAfterPaintHandler(function() {
-        sendAsyncMsg("documentfirstpaint");
-      });
-      this._isContentWindowCreated = true;
-    }
-  },
-
-  _windowResizeHandler(e) {
-    let win = e.target;
-    if (win != content || e.defaultPrevented) {
-      return;
-    }
-
-    debug("resizing window " + win);
-    sendAsyncMsg("resize", { width: e.detail.width, height: e.detail.height });
-
-    // Inform the window implementation that we handled this resize ourselves.
-    e.preventDefault();
-  },
-
-  _contextmenuHandler(e) {
-    debug("Got contextmenu");
-
-    if (e.defaultPrevented) {
-      return;
-    }
-
-    this._ctxCounter++;
-    this._ctxHandlers = {};
-
-    var elem = e.target;
-    var menuData = { systemTargets: [], contextmenu: null };
-    var ctxMenuId = null;
-    var clipboardPlainTextOnly = Services.prefs.getBoolPref(
-      "clipboard.plainTextOnly"
-    );
-    var copyableElements = {
-      image: false,
-      link: false,
-      hasElements() {
-        return this.image || this.link;
-      },
-    };
-
-    // Set the event target as the copy image command needs it to
-    // determine what was context-clicked on.
-    docShell.contentViewer
-      .QueryInterface(Ci.nsIContentViewerEdit)
-      .setCommandNode(elem);
-
-    while (elem && elem.parentNode) {
-      var ctxData = this._getSystemCtxMenuData(elem);
-      if (ctxData) {
-        menuData.systemTargets.push({
-          nodeName: elem.nodeName,
-          data: ctxData,
-        });
-      }
-
-      if (
-        !ctxMenuId &&
-        "hasAttribute" in elem &&
-        elem.hasAttribute("contextmenu")
-      ) {
-        ctxMenuId = elem.getAttribute("contextmenu");
-      }
-
-      // Enable copy image/link option
-      if (elem.nodeName == "IMG") {
-        copyableElements.image = !clipboardPlainTextOnly;
-      } else if (elem.nodeName == "A") {
-        copyableElements.link = true;
-      }
-
-      elem = elem.parentNode;
-    }
-
-    if (ctxMenuId || copyableElements.hasElements()) {
-      var menu = null;
-      if (ctxMenuId) {
-        menu = e.target.ownerDocument.getElementById(ctxMenuId);
-      }
-      menuData.contextmenu = this._buildMenuObj(menu, "", copyableElements);
-    }
-
-    // Pass along the position where the context menu should be located
-    menuData.clientX = e.clientX;
-    menuData.clientY = e.clientY;
-    menuData.screenX = e.screenX;
-    menuData.screenY = e.screenY;
-
-    // The value returned by the contextmenu sync call is true if the embedder
-    // called preventDefault() on its contextmenu event.
-    //
-    // We call preventDefault() on our contextmenu event if the embedder called
-    // preventDefault() on /its/ contextmenu event.  This way, if the embedder
-    // ignored the contextmenu event, BrowserChild will fire a click.
-    if (sendSyncMsg("contextmenu", menuData)[0]) {
-      e.preventDefault();
-    } else {
-      this._ctxHandlers = {};
-    }
-  },
-
-  _getSystemCtxMenuData(elem) {
-    let documentURI = docShell.QueryInterface(Ci.nsIWebNavigation).currentURI
-      .spec;
-
-    if (
-      (ChromeUtils.getClassName(elem) === "HTMLAnchorElement" && elem.href) ||
-      (ChromeUtils.getClassName(elem) === "HTMLAreaElement" && elem.href)
-    ) {
-      return {
-        uri: elem.href,
-        documentURI,
-        text: elem.textContent.substring(0, kLongestReturnedString),
-      };
-    }
-    if (
-      elem instanceof Ci.nsIImageLoadingContent &&
-      (elem.currentRequestFinalURI || elem.currentURI)
-    ) {
-      let uri = elem.currentRequestFinalURI || elem.currentURI;
-      return { uri: uri.spec, documentURI };
-    }
-    if (ChromeUtils.getClassName(elem) === "HTMLImageElement") {
-      return { uri: elem.src, documentURI };
-    }
-    if (
-      ChromeUtils.getClassName(elem) === "HTMLVideoElement" ||
-      ChromeUtils.getClassName(elem) === "HTMLAudioElement"
-    ) {
-      let hasVideo = !(
-        elem.readyState >= elem.HAVE_METADATA &&
-        (elem.videoWidth == 0 || elem.videoHeight == 0)
-      );
-      return { uri: elem.currentSrc || elem.src, hasVideo, documentURI };
-    }
-    if (
-      ChromeUtils.getClassName(elem) === "HTMLInputElement" &&
-      elem.hasAttribute("name")
-    ) {
-      // For input elements, we look for a parent <form> and if there is
-      // one we return the form's method and action uri.
-      let parent = elem.parentNode;
-      while (parent) {
-        if (
-          ChromeUtils.getClassName(parent) === "HTMLFormElement" &&
-          parent.hasAttribute("action")
-        ) {
-          let actionHref = docShell
-            .QueryInterface(Ci.nsIWebNavigation)
-            .currentURI.resolve(parent.getAttribute("action"));
-          let method = parent.hasAttribute("method")
-            ? parent.getAttribute("method").toLowerCase()
-            : "get";
-          return {
-            documentURI,
-            action: actionHref,
-            method,
-            name: elem.getAttribute("name"),
-          };
-        }
-        parent = parent.parentNode;
-      }
-    }
-    return false;
-  },
-
-  _scrollEventHandler(e) {
-    let win = e.target.defaultView;
-    if (win != content) {
-      return;
-    }
-
-    debug("scroll event " + win);
-    sendAsyncMsg("scroll", { top: win.scrollY, left: win.scrollX });
-  },
-
-  _mozScrollAreaChanged(e) {
-    sendAsyncMsg("scrollareachanged", {
-      width: e.width,
-      height: e.height,
-    });
-  },
-
-  _mozRequestedDOMFullscreen(e) {
-    sendAsyncMsg("requested-dom-fullscreen");
-  },
-
-  _mozFullscreenOriginChange(e) {
-    sendAsyncMsg("fullscreen-origin-change", {
-      originNoSuffix: e.target.nodePrincipal.originNoSuffix,
-    });
-  },
-
-  _mozExitDomFullscreen(e) {
-    sendAsyncMsg("exit-dom-fullscreen");
-  },
-
-  _recvFireCtxCallback(data) {
-    debug("Received fireCtxCallback message: (" + data.json.menuitem + ")");
-
-    let doCommandIfEnabled = command => {
-      if (docShell.isCommandEnabled(command)) {
-        docShell.doCommand(command);
-      }
-    };
-
-    if (data.json.menuitem == "copy-image") {
-      doCommandIfEnabled("cmd_copyImage");
-    } else if (data.json.menuitem == "copy-link") {
-      doCommandIfEnabled("cmd_copyLink");
-    } else if (data.json.menuitem in this._ctxHandlers) {
-      this._ctxHandlers[data.json.menuitem].click();
-      this._ctxHandlers = {};
-    } else {
-      // We silently ignore if the embedder uses an incorrect id in the callback
-      debug("Ignored invalid contextmenu invocation");
-    }
-  },
-
-  _buildMenuObj(menu, idPrefix, copyableElements) {
-    var menuObj = { type: "menu", customized: false, items: [] };
-    // Customized context menu
-    if (menu) {
-      this._maybeCopyAttribute(menu, menuObj, "label");
-
-      for (var i = 0, child; (child = menu.children[i++]); ) {
-        if (child.nodeName === "MENU") {
-          menuObj.items.push(
-            this._buildMenuObj(child, idPrefix + i + "_", false)
-          );
-        } else if (child.nodeName === "MENUITEM") {
-          var id = this._ctxCounter + "_" + idPrefix + i;
-          var menuitem = { id, type: "menuitem" };
-          this._maybeCopyAttribute(child, menuitem, "label");
-          this._maybeCopyAttribute(child, menuitem, "icon");
-          this._ctxHandlers[id] = child;
-          menuObj.items.push(menuitem);
-        }
-      }
-
-      if (menuObj.items.length > 0) {
-        menuObj.customized = true;
-      }
-    }
-    // Note: Display "Copy Link" first in order to make sure "Copy Image" is
-    //       put together with other image options if elem is an image link.
-    // "Copy Link" menu item
-    if (copyableElements.link) {
-      menuObj.items.push({ id: "copy-link" });
-    }
-    // "Copy Image" menu item
-    if (copyableElements.image) {
-      menuObj.items.push({ id: "copy-image" });
-    }
-
-    return menuObj;
-  },
-
   /**
    * Called when the window which contains this iframe becomes hidden or
    * visible.
@@ -1043,329 +297,8 @@ BrowserElementChild.prototype = {
     var visible = data.json.visible;
     if (docShell && docShell.isActive !== visible) {
       docShell.isActive = visible;
-
-      // Ensure painting is not frozen if the app goes visible.
-      if (visible && this._paintFrozenTimer) {
-        this.notify();
-      }
     }
   },
-
-  _recvSendMouseEvent(data) {
-    let json = data.json;
-    let utils = content.windowUtils;
-    utils.sendMouseEventToWindow(
-      json.type,
-      json.x,
-      json.y,
-      json.button,
-      json.clickCount,
-      json.modifiers
-    );
-  },
-
-  _recvCanGoBack(data) {
-    var webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
-    sendAsyncMsg("got-can-go-back", {
-      id: data.json.id,
-      successRv: webNav.canGoBack,
-    });
-  },
-
-  _recvCanGoForward(data) {
-    var webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
-    sendAsyncMsg("got-can-go-forward", {
-      id: data.json.id,
-      successRv: webNav.canGoForward,
-    });
-  },
-
-  _recvGoBack(data) {
-    try {
-      docShell.QueryInterface(Ci.nsIWebNavigation).goBack();
-    } catch (e) {
-      // Silently swallow errors; these happen when we can't go back.
-    }
-  },
-
-  _recvGoForward(data) {
-    try {
-      docShell.QueryInterface(Ci.nsIWebNavigation).goForward();
-    } catch (e) {
-      // Silently swallow errors; these happen when we can't go forward.
-    }
-  },
-
-  _recvReload(data) {
-    let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
-    let reloadFlags = data.json.hardReload
-      ? webNav.LOAD_FLAGS_BYPASS_PROXY | webNav.LOAD_FLAGS_BYPASS_CACHE
-      : webNav.LOAD_FLAGS_NONE;
-    try {
-      webNav.reload(reloadFlags);
-    } catch (e) {
-      // Silently swallow errors; these can happen if a used cancels reload
-    }
-  },
-
-  _recvStop(data) {
-    let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
-    webNav.stop(webNav.STOP_NETWORK);
-  },
-
-  // The docShell keeps a weak reference to the progress listener, so we need
-  // to keep a strong ref to it ourselves.
-  _progressListener: {
-    QueryInterface: ChromeUtils.generateQI([
-      Ci.nsIWebProgressListener,
-      Ci.nsISupportsWeakReference,
-    ]),
-    _seenLoadStart: false,
-
-    onLocationChange(webProgress, request, location, flags) {
-      // We get progress events from subshells here, which is kind of weird.
-      if (webProgress != docShell) {
-        return;
-      }
-
-      // Ignore locationchange events which occur before the first loadstart.
-      // These are usually about:blank loads we don't care about.
-      if (!this._seenLoadStart) {
-        return;
-      }
-
-      // Remove password from uri.
-      location = Services.io.createExposableURI(location);
-
-      var webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
-
-      sendAsyncMsg("locationchange", {
-        url: location.spec,
-        canGoBack: webNav.canGoBack,
-        canGoForward: webNav.canGoForward,
-      });
-    },
-
-    // eslint-disable-next-line complexity
-    onStateChange(webProgress, request, stateFlags, status) {
-      if (webProgress != docShell) {
-        return;
-      }
-
-      if (stateFlags & Ci.nsIWebProgressListener.STATE_START) {
-        this._seenLoadStart = true;
-        sendAsyncMsg("loadstart");
-      }
-
-      if (stateFlags & Ci.nsIWebProgressListener.STATE_STOP) {
-        let bgColor = "transparent";
-        try {
-          bgColor = content
-            .getComputedStyle(content.document.body)
-            .getPropertyValue("background-color");
-        } catch (e) {}
-        sendAsyncMsg("loadend", { backgroundColor: bgColor });
-
-        switch (status) {
-          case Cr.NS_OK:
-          case Cr.NS_BINDING_ABORTED:
-          // Ignoring NS_BINDING_ABORTED, which is set when loading page is
-          // stopped.
-          // fall through
-          case Cr.NS_ERROR_PARSED_DATA_CACHED:
-            return;
-
-          // TODO See nsDocShell::DisplayLoadError to see what extra
-          // information we should be annotating this first block of errors
-          // with. Bug 1107091.
-          case Cr.NS_ERROR_UNKNOWN_PROTOCOL:
-            sendAsyncMsg("error", { type: "unknownProtocolFound" });
-            return;
-          case Cr.NS_ERROR_FILE_NOT_FOUND:
-            sendAsyncMsg("error", { type: "fileNotFound" });
-            return;
-          case Cr.NS_ERROR_UNKNOWN_HOST:
-            sendAsyncMsg("error", { type: "dnsNotFound" });
-            return;
-          case Cr.NS_ERROR_CONNECTION_REFUSED:
-            sendAsyncMsg("error", { type: "connectionFailure" });
-            return;
-          case Cr.NS_ERROR_NET_INTERRUPT:
-            sendAsyncMsg("error", { type: "netInterrupt" });
-            return;
-          case Cr.NS_ERROR_NET_TIMEOUT:
-            sendAsyncMsg("error", { type: "netTimeout" });
-            return;
-          case Cr.NS_ERROR_CSP_FRAME_ANCESTOR_VIOLATION:
-            sendAsyncMsg("error", { type: "cspBlocked" });
-            return;
-          case Cr.NS_ERROR_XFO_VIOLATION:
-            sendAsyncMsg("error", { type: "xfoBlocked" });
-            return;
-          case Cr.NS_ERROR_PHISHING_URI:
-            sendAsyncMsg("error", { type: "deceptiveBlocked" });
-            return;
-          case Cr.NS_ERROR_MALWARE_URI:
-            sendAsyncMsg("error", { type: "malwareBlocked" });
-            return;
-          case Cr.NS_ERROR_HARMFUL_URI:
-            sendAsyncMsg("error", { type: "harmfulBlocked" });
-            return;
-          case Cr.NS_ERROR_UNWANTED_URI:
-            sendAsyncMsg("error", { type: "unwantedBlocked" });
-            return;
-          case Cr.NS_ERROR_FORBIDDEN_URI:
-            sendAsyncMsg("error", { type: "forbiddenBlocked" });
-            return;
-
-          case Cr.NS_ERROR_OFFLINE:
-            sendAsyncMsg("error", { type: "offline" });
-            return;
-          case Cr.NS_ERROR_MALFORMED_URI:
-            sendAsyncMsg("error", { type: "malformedURI" });
-            return;
-          case Cr.NS_ERROR_REDIRECT_LOOP:
-            sendAsyncMsg("error", { type: "redirectLoop" });
-            return;
-          case Cr.NS_ERROR_UNKNOWN_SOCKET_TYPE:
-            sendAsyncMsg("error", { type: "unknownSocketType" });
-            return;
-          case Cr.NS_ERROR_NET_RESET:
-            sendAsyncMsg("error", { type: "netReset" });
-            return;
-          case Cr.NS_ERROR_DOCUMENT_NOT_CACHED:
-            sendAsyncMsg("error", { type: "notCached" });
-            return;
-          case Cr.NS_ERROR_DOCUMENT_IS_PRINTMODE:
-            sendAsyncMsg("error", { type: "isprinting" });
-            return;
-          case Cr.NS_ERROR_PORT_ACCESS_NOT_ALLOWED:
-            sendAsyncMsg("error", { type: "deniedPortAccess" });
-            return;
-          case Cr.NS_ERROR_UNKNOWN_PROXY_HOST:
-            sendAsyncMsg("error", { type: "proxyResolveFailure" });
-            return;
-          case Cr.NS_ERROR_PROXY_CONNECTION_REFUSED:
-            sendAsyncMsg("error", { type: "proxyConnectFailure" });
-            return;
-          case Cr.NS_ERROR_INVALID_CONTENT_ENCODING:
-            sendAsyncMsg("error", { type: "contentEncodingFailure" });
-            return;
-          case Cr.NS_ERROR_REMOTE_XUL:
-            sendAsyncMsg("error", { type: "remoteXUL" });
-            return;
-          case Cr.NS_ERROR_UNSAFE_CONTENT_TYPE:
-            sendAsyncMsg("error", { type: "unsafeContentType" });
-            return;
-          case Cr.NS_ERROR_CORRUPTED_CONTENT:
-            sendAsyncMsg("error", { type: "corruptedContentErrorv2" });
-            return;
-          case Cr.NS_ERROR_BLOCKED_BY_POLICY:
-            sendAsyncMsg("error", { type: "blockedByPolicy" });
-            return;
-
-          default:
-            // getErrorClass() will throw if the error code passed in is not a NSS
-            // error code.
-            try {
-              let nssErrorsService = Cc[
-                "@mozilla.org/nss_errors_service;1"
-              ].getService(Ci.nsINSSErrorsService);
-              if (
-                nssErrorsService.getErrorClass(status) ==
-                Ci.nsINSSErrorsService.ERROR_CLASS_BAD_CERT
-              ) {
-                // XXX Is there a point firing the event if the error page is not
-                // certerror? If yes, maybe we should add a property to the
-                // event to to indicate whether there is a custom page. That would
-                // let the embedder have more control over the desired behavior.
-                let errorPage = Services.prefs.getCharPref(
-                  CERTIFICATE_ERROR_PAGE_PREF,
-                  ""
-                );
-
-                if (errorPage == "certerror") {
-                  sendAsyncMsg("error", { type: "certerror" });
-                  return;
-                }
-              }
-            } catch (e) {}
-
-            sendAsyncMsg("error", { type: "other" });
-        }
-      }
-    },
-
-    onSecurityChange(webProgress, request, state) {
-      if (webProgress != docShell) {
-        return;
-      }
-
-      var securityStateDesc;
-      if (state & Ci.nsIWebProgressListener.STATE_IS_SECURE) {
-        securityStateDesc = "secure";
-      } else if (state & Ci.nsIWebProgressListener.STATE_IS_BROKEN) {
-        securityStateDesc = "broken";
-      } else if (state & Ci.nsIWebProgressListener.STATE_IS_INSECURE) {
-        securityStateDesc = "insecure";
-      } else {
-        debug("Unexpected securitychange state!");
-        securityStateDesc = "???";
-      }
-
-      var mixedStateDesc;
-      if (
-        state & Ci.nsIWebProgressListener.STATE_BLOCKED_MIXED_ACTIVE_CONTENT
-      ) {
-        mixedStateDesc = "blocked_mixed_active_content";
-      } else if (
-        state & Ci.nsIWebProgressListener.STATE_LOADED_MIXED_ACTIVE_CONTENT
-      ) {
-        // Note that STATE_LOADED_MIXED_ACTIVE_CONTENT implies STATE_IS_BROKEN
-        mixedStateDesc = "loaded_mixed_active_content";
-      }
-
-      var isEV = !!(
-        state & Ci.nsIWebProgressListener.STATE_IDENTITY_EV_TOPLEVEL
-      );
-      var isMixedContent = !!(
-        state &
-        (Ci.nsIWebProgressListener.STATE_BLOCKED_MIXED_ACTIVE_CONTENT |
-          Ci.nsIWebProgressListener.STATE_LOADED_MIXED_ACTIVE_CONTENT)
-      );
-
-      sendAsyncMsg("securitychange", {
-        state: securityStateDesc,
-        mixedState: mixedStateDesc,
-        extendedValidation: isEV,
-        mixedContent: isMixedContent,
-      });
-    },
-  },
-
-  // Expose the message manager for WebApps and others.
-  _messageManagerPublic: {
-    sendAsyncMessage: global.sendAsyncMessage.bind(global),
-    sendSyncMessage: global.sendSyncMessage.bind(global),
-    addMessageListener: global.addMessageListener.bind(global),
-    removeMessageListener: global.removeMessageListener.bind(global),
-  },
-
-  get messageManager() {
-    return this._messageManagerPublic;
-  },
 };
 
-var api = null;
-if (
-  "DoPreloadPostfork" in this &&
-  typeof this.DoPreloadPostfork === "function"
-) {
-  // If we are preloaded, instantiate BrowserElementChild after a content
-  // process is forked.
-  this.DoPreloadPostfork(function() {
-    api = new BrowserElementChild();
-  });
-} else {
-  api = new BrowserElementChild();
-}
+var api = new BrowserElementChild();
diff --git a/dom/browser-element/BrowserElementCopyPaste.js b/dom/browser-element/BrowserElementCopyPaste.js
deleted file mode 100644
index 323988c164a6..000000000000
--- a/dom/browser-element/BrowserElementCopyPaste.js
+++ /dev/null
@@ -1,138 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- /
-/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-/*
-global addMessageListener
-global removeMessageListener
-global docShell
-global content
-global sendAsyncMsg
-*/
-
-function debug(msg) {
-  // dump("BrowserElementCopyPaste - " + msg + "\n");
-}
-
-debug("loaded");
-
-var CopyPasteAssistent = {
-  COMMAND_MAP: {
-    cut: "cmd_cut",
-    copy: "cmd_copy",
-    paste: "cmd_paste",
-    selectall: "cmd_selectAll",
-  },
-
-  init() {
-    addEventListener(
-      "mozcaretstatechanged",
-      this,
-      /* useCapture = */ true,
-      /* wantsUntrusted = */ false
-    );
-    addMessageListener("browser-element-api:call", this);
-  },
-
-  destroy() {
-    removeEventListener(
-      "mozcaretstatechanged",
-      this,
-      /* useCapture = */ true,
-      /* wantsUntrusted = */ false
-    );
-    removeMessageListener("browser-element-api:call", this);
-  },
-
-  handleEvent(event) {
-    switch (event.type) {
-      case "mozcaretstatechanged":
-        this._caretStateChangedHandler(event);
-        break;
-    }
-  },
-
-  receiveMessage(message) {
-    switch (message.name) {
-      case "browser-element-api:call":
-        this._browserAPIHandler(message);
-        break;
-    }
-  },
-
-  _browserAPIHandler(e) {
-    switch (e.data.msg_name) {
-      case "copypaste-do-command":
-        if (this._isCommandEnabled(e.data.command)) {
-          docShell.doCommand(this.COMMAND_MAP[e.data.command]);
-        }
-        break;
-    }
-  },
-
-  _isCommandEnabled(cmd) {
-    let command = this.COMMAND_MAP[cmd];
-    if (!command) {
-      return false;
-    }
-
-    return docShell.isCommandEnabled(command);
-  },
-
-  _caretStateChangedHandler(e) {
-    e.stopPropagation();
-
-    let boundingClientRect = e.boundingClientRect;
-    this._isCommandEnabled("paste");
-    let zoomFactor =
-      content.innerWidth == 0 ? 1 : content.screen.width / content.innerWidth;
-
-    let detail = {
-      rect: {
-        width: boundingClientRect ? boundingClientRect.width : 0,
-        height: boundingClientRect ? boundingClientRect.height : 0,
-        top: boundingClientRect ? boundingClientRect.top : 0,
-        bottom: boundingClientRect ? boundingClientRect.bottom : 0,
-        left: boundingClientRect ? boundingClientRect.left : 0,
-        right: boundingClientRect ? boundingClientRect.right : 0,
-      },
-      commands: {
-        canSelectAll: this._isCommandEnabled("selectall"),
-        canCut: this._isCommandEnabled("cut"),
-        canCopy: this._isCommandEnabled("copy"),
-        canPaste: this._isCommandEnabled("paste"),
-      },
-      zoomFactor,
-      reason: e.reason,
-      collapsed: e.collapsed,
-      caretVisible: e.caretVisible,
-      selectionVisible: e.selectionVisible,
-      selectionEditable: e.selectionEditable,
-      selectedTextContent: e.selectedTextContent,
-    };
-
-    // Get correct geometry information if we have nested iframe.
-    let currentWindow = e.target.defaultView;
-    while (currentWindow.realFrameElement) {
-      let currentRect = currentWindow.realFrameElement.getBoundingClientRect();
-      detail.rect.top += currentRect.top;
-      detail.rect.bottom += currentRect.top;
-      detail.rect.left += currentRect.left;
-      detail.rect.right += currentRect.left;
-      currentWindow = currentWindow.realFrameElement.ownerGlobal;
-
-      let targetDocShell = currentWindow.docShell;
-      if (targetDocShell.isMozBrowser) {
-        break;
-      }
-    }
-
-    sendAsyncMsg("caretstatechanged", detail);
-  },
-};
-
-CopyPasteAssistent.init();
diff --git a/dom/browser-element/BrowserElementParent.jsm b/dom/browser-element/BrowserElementParent.jsm
index b3b88435bcc8..c0b5ea614693 100644
--- a/dom/browser-element/BrowserElementParent.jsm
+++ b/dom/browser-element/BrowserElementParent.jsm
@@ -27,45 +27,8 @@ function handleWindowEvent(e) {
   }
 }
 
-function defineNoReturnMethod(fn) {
-  return function method() {
-    if (!this._domRequestReady) {
-      // Remote browser haven't been created, we just queue the API call.
-      let args = [this, ...arguments];
-      this._pendingAPICalls.push(method.bind.apply(fn, args));
-      return;
-    }
-    if (this._isAlive()) {
-      fn.apply(this, arguments);
-    }
-  };
-}
-
-function definePromiseMethod(msgName) {
-  return function() {
-    return this._sendAsyncRequest(msgName);
-  };
-}
-
 function BrowserElementParent() {
   debug("Creating new BrowserElementParent object");
-  this._promiseCounter = 0;
-  this._domRequestReady = false;
-  this._pendingAPICalls = [];
-  this._pendingPromises = {};
-  this._pendingDOMFullscreen = false;
-
-  Services.obs.addObserver(
-    this,
-    "oop-frameloader-crashed",
-    /* ownsWeak = */ true
-  );
-  Services.obs.addObserver(
-    this,
-    "ask-children-to-execute-copypaste-command",
-    /* ownsWeak = */ true
-  );
-  Services.obs.addObserver(this, "back-docommand", /* ownsWeak = */ true);
 }
 
 BrowserElementParent.prototype = {
@@ -74,7 +37,6 @@ BrowserElementParent.prototype = {
   contractID: "@mozilla.org/dom/browser-element-api;1",
   QueryInterface: ChromeUtils.generateQI([
     Ci.nsIBrowserElementAPI,
-    Ci.nsIObserver,
     Ci.nsISupportsWeakReference,
   ]),
 
@@ -99,7 +61,7 @@ BrowserElementParent.prototype = {
     if (!this._window._browserElementParents) {
       this._window._browserElementParents = new WeakMap();
       let handler = handleWindowEvent.bind(this._window);
-      let windowEvents = ["visibilitychange", "fullscreenchange"];
+      let windowEvents = ["visibilitychange"];
       for (let event of windowEvents) {
         Services.els.addSystemEventListener(
           this._window,
@@ -125,21 +87,6 @@ BrowserElementParent.prototype = {
     this._mm.sendAsyncMessage("browser-element-api:destroy");
   },
 
-  _runPendingAPICall() {
-    if (!this._pendingAPICalls) {
-      return;
-    }
-    for (let i = 0; i < this._pendingAPICalls.length; i++) {
-      try {
-        this._pendingAPICalls[i]();
-      } catch (e) {
-        // throw the exceptions from pending functions.
-        debug("Exception when running pending API call: " + e);
-      }
-    }
-    delete this._pendingAPICalls;
-  },
-
   _setupMessageListener() {
     this._mm = this._frameLoader.messageManager;
     this._mm.addMessageListener("browser-element-api:call", this);
@@ -156,36 +103,10 @@ BrowserElementParent.prototype = {
     // on data.msg_name
     let mmCalls = {
       hello: this._recvHello,
-      loadstart: this._fireProfiledEventFromMsg,
-      loadend: this._fireProfiledEventFromMsg,
-      close: this._fireEventFromMsg,
-      error: this._fireEventFromMsg,
-      firstpaint: this._fireProfiledEventFromMsg,
-      documentfirstpaint: this._fireProfiledEventFromMsg,
-      "got-can-go-back": this._gotAsyncResult,
-      "got-can-go-forward": this._gotAsyncResult,
-      "requested-dom-fullscreen": this._requestedDOMFullscreen,
-      "fullscreen-origin-change": this._fullscreenOriginChange,
-      "exit-dom-fullscreen": this._exitDomFullscreen,
-      scrollviewchange: this._handleScrollViewChange,
-      caretstatechanged: this._handleCaretStateChanged,
     };
 
     let mmSecuritySensitiveCalls = {
-      audioplaybackchange: this._fireEventFromMsg,
       showmodalprompt: this._handleShowModalPrompt,
-      contextmenu: this._fireCtxMenuEvent,
-      securitychange: this._fireEventFromMsg,
-      locationchange: this._fireEventFromMsg,
-      iconchange: this._fireEventFromMsg,
-      scrollareachanged: this._fireEventFromMsg,
-      titlechange: this._fireProfiledEventFromMsg,
-      opensearch: this._fireEventFromMsg,
-      metachange: this._fireEventFromMsg,
-      resize: this._fireEventFromMsg,
-      activitydone: this._fireEventFromMsg,
-      scroll: this._fireEventFromMsg,
-      opentab: this._fireEventFromMsg,
     };
 
     if (aMsg.data.msg_name in mmCalls) {
@@ -219,60 +140,6 @@ BrowserElementParent.prototype = {
     return this._frameElement.ownerGlobal;
   },
 
-  get _windowUtils() {
-    return this._window.windowUtils;
-  },
-
-  promptAuth(authDetail, callback) {
-    let evt;
-    let callbackCalled = false;
-    let cancelCallback = function() {
-      if (!callbackCalled) {
-        callbackCalled = true;
-        callback(false, null, null);
-      }
-    };
-
-    // We don't handle password-only prompts.
-    if (authDetail.isOnlyPassword) {
-      cancelCallback();
-      return;
-    }
-
-    /* username and password */
-    let detail = {
-      host: authDetail.host,
-      path: authDetail.path,
-      realm: authDetail.realm,
-      isProxy: authDetail.isProxy,
-    };
-
-    evt = this._createEvent(
-      "usernameandpasswordrequired",
-      detail,
-      /* cancelable */ true
-    );
-    Cu.exportFunction(
-      function(username, password) {
-        if (callbackCalled) {
-          return;
-        }
-        callbackCalled = true;
-        callback(true, username, password);
-      },
-      evt.detail,
-      { defineAs: "authenticate" }
-    );
-
-    Cu.exportFunction(cancelCallback, evt.detail, { defineAs: "cancel" });
-
-    this._frameElement.dispatchEvent(evt);
-
-    if (!evt.defaultPrevented) {
-      cancelCallback();
-    }
-  },
-
   _sendAsyncMsg(msg, data) {
     try {
       if (!data) {
@@ -297,47 +164,6 @@ BrowserElementParent.prototype = {
     if (this._window.document.hidden) {
       this._ownerVisibilityChange();
     }
-
-    if (!this._domRequestReady) {
-      // At least, one message listener such as for hello is registered.
-      // So we can use sendAsyncMessage now.
-      this._domRequestReady = true;
-      this._runPendingAPICall();
-    }
-  },
-
-  _fireCtxMenuEvent(data) {
-    let detail = data.json;
-    let evtName = detail.msg_name;
-
-    debug("fireCtxMenuEventFromMsg: " + evtName + " " + detail);
-    let evt = this._createEvent(evtName, detail, /* cancellable */ true);
-
-    if (detail.contextmenu) {
-      var self = this;
-      Cu.exportFunction(
-        function(id) {
-          self._sendAsyncMsg("fire-ctx-callback", { menuitem: id });
-        },
-        evt.detail,
-        { defineAs: "contextMenuItemSelected" }
-      );
-    }
-
-    // The embedder may have default actions on context menu events, so
-    // we fire a context menu event even if the child didn't define a
-    // custom context menu
-    return !this._frameElement.dispatchEvent(evt);
-  },
-
-  /**
-   * add profiler marker for each event fired.
-   */
-  _fireProfiledEventFromMsg(data) {
-    if (Services.profiler !== undefined) {
-      Services.profiler.AddMarker(data.json.msg_name);
-    }
-    this._fireEventFromMsg(data);
   },
 
   /**
@@ -411,51 +237,6 @@ BrowserElementParent.prototype = {
     }
   },
 
-  // Called when state of accessible caret in child has changed.
-  // The fields of data is as following:
-  //  - rect: Contains bounding rectangle of selection, Include width, height,
-  //          top, bottom, left and right.
-  //  - commands: Describe what commands can be executed in child. Include canSelectAll,
-  //              canCut, canCopy and canPaste. For example: if we want to check if cut
-  //              command is available, using following code, if (data.commands.canCut) {}.
-  //  - zoomFactor: Current zoom factor in child frame.
-  //  - reason: The reason causes the state changed. Include "visibilitychange",
-  //            "updateposition", "longpressonemptycontent", "taponcaret", "presscaret",
-  //            "releasecaret".
-  //  - collapsed: Indicate current selection is collapsed or not.
-  //  - caretVisible: Indicate the caret visiibility.
-  //  - selectionVisible: Indicate current selection is visible or not.
-  //  - selectionEditable: Indicate current selection is editable or not.
-  //  - selectedTextContent: Contains current selected text content, which is
-  //                         equivalent to the string returned by Selection.toString().
-  _handleCaretStateChanged(data) {
-    let evt = this._createEvent(
-      "caretstatechanged",
-      data.json,
-      /* cancelable = */ false
-    );
-
-    let self = this;
-    function sendDoCommandMsg(cmd) {
-      let data = { command: cmd };
-      self._sendAsyncMsg("copypaste-do-command", data);
-    }
-    Cu.exportFunction(sendDoCommandMsg, evt.detail, {
-      defineAs: "sendDoCommandMsg",
-    });
-
-    this._frameElement.dispatchEvent(evt);
-  },
-
-  _handleScrollViewChange(data) {
-    let evt = this._createEvent(
-      "scrollviewchange",
-      data.json,
-      /* cancelable = */ false
-    );
-    this._frameElement.dispatchEvent(evt);
-  },
-
   _createEvent(evtName, detail, cancelable) {
     // This will have to change if we ever want to send a CustomEvent with null
     // detail.  For now, it's OK.
@@ -474,117 +255,6 @@ BrowserElementParent.prototype = {
     });
   },
 
-  /**
-   * Kick off an async operation in the child process.
-   *
-   * We'll send a message called |msgName| to the child process, passing along
-   * an object with two fields:
-   *
-   *  - id:  the ID of this async call.
-   *  - arg: arguments to pass to the child along with this async call.
-   *
-   * We expect the child to pass the ID back to us upon completion of the
-   * call.  See _gotAsyncResult.
-   */
-  _sendAsyncRequest(msgName, args) {
-    let id = "req_" + this._promiseCounter++;
-    let resolve, reject;
-    let p = new this._window.Promise((res, rej) => {
-      resolve = res;
-      reject = rej;
-    });
-    let self = this;
-    let send = function() {
-      if (!self._isAlive()) {
-        return;
-      }
-      if (self._sendAsyncMsg(msgName, { id, args })) {
-        self._pendingPromises[id] = { p, resolve, reject };
-      } else {
-        reject(new this._window.DOMException("fail"));
-      }
-    };
-    if (this._domRequestReady) {
-      send();
-    } else {
-      // Child haven't been loaded.
-      this._pendingAPICalls.push(send);
-    }
-    return p;
-  },
-
-  /**
-   * Called when the child process finishes handling an async call.  data.json
-   * must have the fields [id, successRv], if the async call was successful, or
-   * [id, errorMsg], if the call was not successful.
-   *
-   * The fields have the following meanings:
-   *
-   *  - id:        the ID of the async call (see _sendAsyncRequest)
-   *  - successRv: the call's return value, if the call succeeded
-   *  - errorMsg:  the message to pass to the Promise reject callback, if the
-   *               call failed.
-   *
-   */
-  _gotAsyncResult(data) {
-    let p = this._pendingPromises[data.json.id];
-    delete this._pendingPromises[data.json.id];
-
-    if ("successRv" in data.json) {
-      debug("Successful gotAsyncResult.");
-      let clientObj = Cu.cloneInto(data.json.successRv, this._window);
-      p.resolve(clientObj);
-    } else {
-      debug("Got error in gotAsyncResult.");
-      p.reject(
-        new this._window.DOMException(
-          Cu.cloneInto(data.json.errorMsg, this._window)
-        )
-      );
-    }
-  },
-
-  sendMouseEvent: defineNoReturnMethod(function(
-    type,
-    x,
-    y,
-    button,
-    clickCount,
-    modifiers
-  ) {
-    // This method used to attempt to transform from the parent
-    // coordinate space to the child coordinate space, but the
-    // transform was always a no-op, because this._frameLoader.remoteTab
-    // was null.
-    this._sendAsyncMsg("send-mouse-event", {
-      type,
-      x,
-      y,
-      button,
-      clickCount,
-      modifiers,
-    });
-  }),
-
-  getCanGoBack: definePromiseMethod("get-can-go-back"),
-  getCanGoForward: definePromiseMethod("get-can-go-forward"),
-
-  goBack: defineNoReturnMethod(function() {
-    this._sendAsyncMsg("go-back");
-  }),
-
-  goForward: defineNoReturnMethod(function() {
-    this._sendAsyncMsg("go-forward");
-  }),
-
-  reload: defineNoReturnMethod(function(hardReload) {
-    this._sendAsyncMsg("reload", { hardReload });
-  }),
-
-  stop: defineNoReturnMethod(function() {
-    this._sendAsyncMsg("stop");
-  }),
-
   /**
    * Called when the visibility of the window which owns this iframe changes.
    */
@@ -594,68 +264,11 @@ BrowserElementParent.prototype = {
     });
   },
 
-  _requestedDOMFullscreen() {
-    this._pendingDOMFullscreen = true;
-    this._windowUtils.remoteFrameFullscreenChanged(this._frameElement);
-  },
-
-  _fullscreenOriginChange(data) {
-    Services.obs.notifyObservers(
-      this._frameElement,
-      "fullscreen-origin-change",
-      data.json.originNoSuffix
-    );
-  },
-
-  _exitDomFullscreen(data) {
-    this._windowUtils.remoteFrameFullscreenReverted();
-  },
-
   _handleOwnerEvent(evt) {
     switch (evt.type) {
       case "visibilitychange":
         this._ownerVisibilityChange();
         break;
-      case "fullscreenchange":
-        if (!this._window.document.fullscreenElement) {
-          this._sendAsyncMsg("exit-fullscreen");
-        } else if (this._pendingDOMFullscreen) {
-          this._pendingDOMFullscreen = false;
-          this._sendAsyncMsg("entered-fullscreen");
-        }
-        break;
-    }
-  },
-
-  _fireFatalError() {
-    let evt = this._createEvent(
-      "error",
-      { type: "fatal" },
-      /* cancelable = */ false
-    );
-    this._frameElement.dispatchEvent(evt);
-  },
-
-  observe(subject, topic, data) {
-    switch (topic) {
-      case "oop-frameloader-crashed":
-        if (this._isAlive() && subject == this._frameLoader) {
-          this._fireFatalError();
-        }
-        break;
-      case "ask-children-to-execute-copypaste-command":
-        if (this._isAlive() && this._frameElement == subject.wrappedJSObject) {
-          this._sendAsyncMsg("copypaste-do-command", { command: data });
-        }
-        break;
-      case "back-docommand":
-        if (this._isAlive() && this._frameLoader.visible) {
-          this.goBack();
-        }
-        break;
-      default:
-        debug("Unknown topic: " + topic);
-        break;
     }
   },
 };
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 6038dc494644..48dfb822c884 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -3155,10 +3155,6 @@ nsresult EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
           }
         }
 
-        if (!suppressBlur) {
-          suppressBlur = nsContentUtils::IsUserFocusIgnored(activeContent);
-        }
-
         // When a root content which isn't editable but has an editable HTML
         // <body> element is clicked, we should redirect the focus to the
         // the <body> element.  E.g., when an user click bottom of the editor
diff --git a/dom/html/nsBrowserElement.cpp b/dom/html/nsBrowserElement.cpp
index 9c7b91250b26..69284e77ab24 100644
--- a/dom/html/nsBrowserElement.cpp
+++ b/dom/html/nsBrowserElement.cpp
@@ -7,7 +7,6 @@
 #include "nsBrowserElement.h"
 
 #include "mozilla/Preferences.h"
-#include "mozilla/dom/BrowserElementBinding.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/ToJSValue.h"
@@ -55,86 +54,4 @@ void nsBrowserElement::DestroyBrowserElementFrameScripts() {
   mBrowserElementAPI->DestroyFrameScripts();
 }
 
-void nsBrowserElement::SendMouseEvent(const nsAString& aType, uint32_t aX,
-                                      uint32_t aY, uint32_t aButton,
-                                      uint32_t aClickCount, uint32_t aModifiers,
-                                      ErrorResult& aRv) {
-  NS_ENSURE_TRUE_VOID(IsBrowserElementOrThrow(aRv));
-
-  nsresult rv = mBrowserElementAPI->SendMouseEvent(aType, aX, aY, aButton,
-                                                   aClickCount, aModifiers);
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-  }
-}
-
-void nsBrowserElement::GoBack(ErrorResult& aRv) {
-  NS_ENSURE_TRUE_VOID(IsBrowserElementOrThrow(aRv));
-
-  nsresult rv = mBrowserElementAPI->GoBack();
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-  }
-}
-
-void nsBrowserElement::GoForward(ErrorResult& aRv) {
-  NS_ENSURE_TRUE_VOID(IsBrowserElementOrThrow(aRv));
-
-  nsresult rv = mBrowserElementAPI->GoForward();
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-  }
-}
-
-void nsBrowserElement::Reload(bool aHardReload, ErrorResult& aRv) {
-  NS_ENSURE_TRUE_VOID(IsBrowserElementOrThrow(aRv));
-
-  nsresult rv = mBrowserElementAPI->Reload(aHardReload);
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-  }
-}
-
-void nsBrowserElement::Stop(ErrorResult& aRv) {
-  NS_ENSURE_TRUE_VOID(IsBrowserElementOrThrow(aRv));
-
-  nsresult rv = mBrowserElementAPI->Stop();
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-  }
-}
-
-already_AddRefed<Promise> nsBrowserElement::GetCanGoBack(ErrorResult& aRv) {
-  NS_ENSURE_TRUE(IsBrowserElementOrThrow(aRv), nullptr);
-
-  RefPtr<Promise> p;
-  nsresult rv = mBrowserElementAPI->GetCanGoBack(getter_AddRefs(p));
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return nullptr;
-  }
-
-  return p.forget();
-}
-
-already_AddRefed<Promise> nsBrowserElement::GetCanGoForward(ErrorResult& aRv) {
-  NS_ENSURE_TRUE(IsBrowserElementOrThrow(aRv), nullptr);
-
-  RefPtr<Promise> p;
-  nsresult rv = mBrowserElementAPI->GetCanGoForward(getter_AddRefs(p));
-
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
-    return nullptr;
-  }
-
-  return p.forget();
-}
-
 }  // namespace mozilla
diff --git a/dom/ipc/jar.mn b/dom/ipc/jar.mn
index 1e8431313788..8cc8826703d5 100644
--- a/dom/ipc/jar.mn
+++ b/dom/ipc/jar.mn
@@ -7,4 +7,3 @@ toolkit.jar:
         content/global/remote-test-ipc.js (remote-test.js)
         content/global/BrowserElementChild.js (../browser-element/BrowserElementChild.js)
         content/global/BrowserElementChildPreload.js (../browser-element/BrowserElementChildPreload.js)
-        content/global/BrowserElementCopyPaste.js (../browser-element/BrowserElementCopyPaste.js)
diff --git a/dom/webidl/BrowserElement.webidl b/dom/webidl/BrowserElement.webidl
deleted file mode 100644
index c0d84bb8fecb..000000000000
--- a/dom/webidl/BrowserElement.webidl
+++ /dev/null
@@ -1,47 +0,0 @@
-/* -*- 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 mixin BrowserElement {
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  void sendMouseEvent(DOMString type,
-                      unsigned long x,
-                      unsigned long y,
-                      unsigned long button,
-                      unsigned long clickCount,
-                      unsigned long modifiers);
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  void goBack();
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  void goForward();
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  void reload(optional boolean hardReload = false);
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  void stop();
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  Promise<boolean> getCanGoBack();
-
-  [Throws,
-   Pref="dom.mozBrowserFramesEnabled",
-   ChromeOnly]
-  Promise<boolean> getCanGoForward();
-};
diff --git a/dom/webidl/HTMLIFrameElement.webidl b/dom/webidl/HTMLIFrameElement.webidl
index fc786738e478..7efc3da0b362 100644
--- a/dom/webidl/HTMLIFrameElement.webidl
+++ b/dom/webidl/HTMLIFrameElement.webidl
@@ -63,14 +63,7 @@ partial interface HTMLIFrameElement {
   Document? getSVGDocument();
 };
 
-partial interface HTMLIFrameElement {
-  // nsIDOMMozBrowserFrame
-  [ChromeOnly,SetterThrows]
-           attribute boolean mozbrowser;
-};
-
 HTMLIFrameElement includes MozFrameLoaderOwner;
-HTMLIFrameElement includes BrowserElement;
 
 // https://w3c.github.io/webappsec-feature-policy/#idl-index
 partial interface HTMLIFrameElement {
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index b0d160761095..f3927a59a48f 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -49,9 +49,6 @@ with Files("Blob*"):
 with Files("BroadcastChannel.webidl"):
     BUG_COMPONENT = ("Core", "DOM: postMessage")
 
-with Files("BrowserElement*"):
-    BUG_COMPONENT = ("Core", "DOM: Core & HTML")
-
 with Files("CSP*"):
     BUG_COMPONENT = ("Core", "DOM: Security")
 
@@ -431,7 +428,6 @@ WEBIDL_FILES = [
     'BiquadFilterNode.webidl',
     'Blob.webidl',
     'BroadcastChannel.webidl',
-    'BrowserElement.webidl',
     'BrowserElementDictionaries.webidl',
     'Cache.webidl',
     'CacheStorage.webidl',