--- a/b2g/chrome/content/shell.js
+++ b/b2g/chrome/content/shell.js
@@ -345,17 +345,16 @@ var shell = {
 
     window.addEventListener('MozApplicationManifest', this);
     window.addEventListener('MozAfterPaint', this);
     window.addEventListener('sizemodechange', this);
     window.addEventListener('unload', this);
     this.contentBrowser.addEventListener('mozbrowserloadstart', this, true);
     this.contentBrowser.addEventListener('mozbrowserselectionstatechanged', this, true);
     this.contentBrowser.addEventListener('mozbrowserscrollviewchange', this, true);
-    this.contentBrowser.addEventListener('mozbrowsercaretstatechanged', this);
 
     CustomEventManager.init();
     WebappsHelper.init();
     UserAgentOverrides.init();
     CaptivePortalLoginHelper.init();
 
     this.contentBrowser.src = homeURL;
     this.isHomeLoaded = false;
@@ -376,17 +375,16 @@ var shell = {
     window.removeEventListener('unload', this);
     window.removeEventListener('keydown', this, true);
     window.removeEventListener('keyup', this, true);
     window.removeEventListener('MozApplicationManifest', this);
     window.removeEventListener('sizemodechange', this);
     this.contentBrowser.removeEventListener('mozbrowserloadstart', this, true);
     this.contentBrowser.removeEventListener('mozbrowserselectionstatechanged', this, true);
     this.contentBrowser.removeEventListener('mozbrowserscrollviewchange', this, true);
-    this.contentBrowser.removeEventListener('mozbrowsercaretstatechanged', this);
     ppmm.removeMessageListener("content-handler", this);
 
     UserAgentOverrides.uninit();
   },
 
   // If this key event represents a hardware button which needs to be send as
   // a message, broadcasts it with the message set to 'xxx-button-press' or
   // 'xxx-button-release'.
@@ -487,38 +485,16 @@ var shell = {
         data.offsetY = offsetY;
 
         DoCommandHelper.setEvent(evt);
         shell.sendChromeEvent({
           type: 'selectionstatechanged',
           detail: data,
         });
         break;
-      case 'mozbrowsercaretstatechanged':
-        {
-          let elt = evt.target;
-          let win = elt.ownerDocument.defaultView;
-          let offsetX = win.mozInnerScreenX - window.mozInnerScreenX;
-          let offsetY = win.mozInnerScreenY - window.mozInnerScreenY;
-
-          let rect = elt.getBoundingClientRect();
-          offsetX += rect.left;
-          offsetY += rect.top;
-
-          let data = evt.detail;
-          data.offsetX = offsetX;
-          data.offsetY = offsetY;
-          data.sendDoCommandMsg = null;
-
-          shell.sendChromeEvent({
-            type: 'caretstatechanged',
-            detail: data,
-          });
-        }
-        break;
 
       case 'MozApplicationManifest':
         try {
           if (!Services.prefs.getBoolPref('browser.cache.offline.enable'))
             return;
 
           let contentWindow = evt.originalTarget.defaultView;
           let documentElement = contentWindow.document.documentElement;
@@ -737,20 +713,16 @@ var CustomEventManager = {
       case 'inputmethod-update-layouts':
       case 'inputregistry-add':
       case 'inputregistry-remove':
         KeyboardHelper.handleEvent(detail);
         break;
       case 'do-command':
         DoCommandHelper.handleEvent(detail.cmd);
         break;
-      case 'copypaste-do-command':
-        Services.obs.notifyObservers({ wrappedJSObject: shell.contentBrowser },
-                                     'ask-children-to-execute-copypaste-command', detail.cmd);
-        break;
     }
   }
 }
 
 let DoCommandHelper = {
   _event: null,
   setEvent: function docommand_setEvent(evt) {
     this._event = evt;

--- a/dom/browser-element/BrowserElementChild.js
+++ b/dom/browser-element/BrowserElementChild.js
@@ -29,25 +29,22 @@ function isTopBrowserElement(docShell) {
     if (docShell && docShell.isBrowserOrApp) {
       return false;
     }
   }
   return true;
 }
 
 if (!('BrowserElementIsPreloaded' in this)) {
-  if (isTopBrowserElement(docShell)) {
-    if (Services.prefs.getBoolPref("dom.mozInputMethod.enabled")) {
-      try {
-        Services.scriptloader.loadSubScript("chrome://global/content/forms.js");
-      } catch (e) {
-      }
+  if (isTopBrowserElement(docShell) &&
+      Services.prefs.getBoolPref("dom.mozInputMethod.enabled")) {
+    try {
+      Services.scriptloader.loadSubScript("chrome://global/content/forms.js");
+    } catch (e) {
     }
-
-    Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementCopyPaste.js");
   }
 
   if (Services.prefs.getIntPref("dom.w3c_touch_events.enabled") == 1) {
     if (docShell.asyncPanZoomEnabled === false) {
       Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementPanningAPZDisabled.js");
       ContentPanningAPZDisabled.init();
     }
 

deleted file mode 100644
--- a/dom/browser-element/BrowserElementCopyPaste.js
+++ /dev/null
@@ -1,90 +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";
-
-dump("###################################### BrowserElementCopyPaste.js loaded\n");
-
-let CopyPasteAssistent = {
-  COMMAND_MAP: {
-    'cut': 'cmd_cut',
-    'copy': 'cmd_copyAndCollapseToEnd',
-    'paste': 'cmd_paste',
-    'selectall': 'cmd_selectAll'
-  },
-
-  init: function() {
-    addEventListener('mozcaretstatechanged',
-                     this._caretStateChangedHandler.bind(this),
-                     /* useCapture = */ true,
-                     /* wantsUntrusted = */ false);
-    addMessageListener('browser-element-api:call', this._browserAPIHandler.bind(this));
-  },
-
-  _browserAPIHandler: function(e) {
-    switch (e.data.msg_name) {
-      case 'copypaste-do-command':
-        if (this._isCommandEnabled(e.data.command)) {
-          docShell.doCommand(COMMAND_MAP[e.data.command]);
-        }
-        break;
-    }
-  },
-
-  _isCommandEnabled: function(cmd) {
-    let command = this.COMMAND_MAP[cmd];
-    if (!command) {
-      return false;
-    }
-
-    return docShell.isCommandEnabled(command);
-  },
-
-  _caretStateChangedHandler: function(e) {
-    e.stopPropagation();
-
-    let boundingClientRect = e.boundingClientRect;
-    let canPaste = 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: zoomFactor,
-      reason: e.reason,
-      collapsed: e.collapsed,
-      caretVisible: e.caretVisible,
-      selectionVisible: e.selectionVisible
-    };
-
-    // 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.ownerDocument.defaultView;
-    }
-
-    sendAsyncMsg('caretstatechanged', detail);
-  },
-};
-
-CopyPasteAssistent.init();

--- a/dom/browser-element/BrowserElementParent.js
+++ b/dom/browser-element/BrowserElementParent.js
@@ -82,17 +82,16 @@ function BrowserElementParent() {
   this._domRequestReady = false;
   this._pendingAPICalls = [];
   this._pendingDOMRequests = {};
   this._pendingSetInputMethodActive = [];
   this._nextPaintListeners = [];
 
   Services.obs.addObserver(this, 'oop-frameloader-crashed', /* ownsWeak = */ true);
   Services.obs.addObserver(this, 'copypaste-docommand', /* ownsWeak = */ true);
-  Services.obs.addObserver(this, 'ask-children-to-execute-copypaste-command', /* ownsWeak = */ true);
 }
 
 BrowserElementParent.prototype = {
 
   classDescription: "BrowserElementAPI implementation",
   classID: Components.ID("{9f171ac4-0939-4ef8-b360-3408aedc3060}"),
   contractID: "@mozilla.org/dom/browser-element-api;1",
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIBrowserElementAPI,
@@ -199,17 +198,16 @@ BrowserElementParent.prototype = {
       "entered-dom-fullscreen": this._enteredDomFullscreen,
       "fullscreen-origin-change": this._fullscreenOriginChange,
       "exited-dom-fullscreen": this._exitedDomFullscreen,
       "got-visible": this._gotDOMRequestResult,
       "visibilitychange": this._childVisibilityChange,
       "got-set-input-method-active": this._gotDOMRequestResult,
       "selectionstatechanged": this._handleSelectionStateChanged,
       "scrollviewchange": this._handleScrollViewChange,
-      "caretstatechanged": this._handleCaretStateChanged,
     };
 
     let mmSecuritySensitiveCalls = {
       "showmodalprompt": this._handleShowModalPrompt,
       "contextmenu": this._fireCtxMenuEvent,
       "securitychange": this._fireEventFromMsg,
       "locationchange": this._fireEventFromMsg,
       "iconchange": this._fireEventFromMsg,
@@ -435,44 +433,16 @@ BrowserElementParent.prototype = {
   },
 
   _handleSelectionStateChanged: function(data) {
     let evt = this._createEvent('selectionstatechanged', data.json,
                                 /* cancelable = */ false);
     this._frameElement.dispatchEvent(evt);
   },
 
-  // 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.
-  _handleCaretStateChanged: function(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: function(data) {
     let evt = this._createEvent("scrollviewchange", data.json,
                                 /* cancelable = */ false);
     this._frameElement.dispatchEvent(evt);
   },
 
   _createEvent: function(evtName, detail, cancelable) {
     // This will have to change if we ever want to send a CustomEvent with null
@@ -1004,21 +974,16 @@ BrowserElementParent.prototype = {
         this._fireFatalError();
       }
       break;
     case 'copypaste-docommand':
       if (this._isAlive() && this._frameElement.isEqualNode(subject.wrappedJSObject)) {
         this._sendAsyncMsg('do-command', { command: data });
       }
       break;
-    case 'ask-children-to-execute-copypaste-command':
-      if (this._isAlive() && this._frameElement == subject.wrappedJSObject) {
-        this._sendAsyncMsg('copypaste-do-command', { command: data });
-      }
-      break;
     default:
       debug('Unknown topic: ' + topic);
       break;
     };
   },
 };
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([BrowserElementParent]);

--- a/dom/browser-element/mochitest/browserElementTestHelpers.js
+++ b/dom/browser-element/mochitest/browserElementTestHelpers.js
@@ -60,20 +60,16 @@ const browserElementTestHelpers = {
   setEnabledPref: function(value) {
     this._setPref('dom.mozBrowserFramesEnabled', value);
   },
 
   setSelectionChangeEnabledPref: function(value) {
     this._setPref('selectioncaret.enabled', value);
   },
 
-  setAccessibleCaretEnabledPref: function(value) {
-    this._setPref('layout.accessiblecaret.enabled', value);
-  },
-
   getOOPByDefaultPref: function() {
     return this._getBoolPref("dom.ipc.browser_frames.oop_by_default");
   },
 
   addPermission: function() {
     this.lockTestReady();
     SpecialPowers.pushPermissions(
       [{'type': "browser", 'allow': 1, 'context': document}],

--- a/dom/browser-element/mochitest/browserElement_CopyPaste.js
+++ b/dom/browser-element/mochitest/browserElement_CopyPaste.js
@@ -16,17 +16,16 @@ var mm;
 var iframeOuter;
 var iframeInner;
 var state = 0;
 var stateMeaning;
 var defaultData;
 var pasteData;
 var focusScript;
 var createEmbededFrame = false;
-var testAccessibleCaret = false;
 
 function copyToClipboard(str) {
   gTextarea.value = str;
   SpecialPowers.wrap(gTextarea).editor.selectAll();
   SpecialPowers.wrap(gTextarea).editor.copy();
 }
 
 function getScriptForGetContent() {
@@ -156,58 +155,47 @@ function dispatchTest(e) {
                    "</body>" +
                    "<script>document.designMode='on';</script>" +
                    "</html>";
       stateMeaning = " (test: normal div with designMode:on)";
       focusScript = "var elt=content.document.getElementById('text');elt.focus();";
       break;
     default:
       if (createEmbededFrame || browserElementTestHelpers.getOOPByDefaultPref()) {
-        if (testAccessibleCaret) {
-          SimpleTest.finish();
-          return;
-        } else {
-          testAccessibleCaret = true;
-          createEmbededFrame = false;
-          browserElementTestHelpers.setSelectionChangeEnabledPref(false);
-          browserElementTestHelpers.setAccessibleCaretEnabledPref(true);
-        }
+        SimpleTest.finish();
       } else {
         createEmbededFrame = true;
+
+        // clean up and run test again.
+        document.body.removeChild(iframeOuter);
+        document.body.removeChild(gTextarea);
+        state = 0;
+        runTest();
       }
-
-      // clean up and run test again.
-      document.body.removeChild(iframeOuter);
-      document.body.removeChild(gTextarea);
-      state = 0;
-      runTest();
       break;
   }
 }
 
 function isChildProcess() {
   return SpecialPowers.Cc["@mozilla.org/xre/app-info;1"]
                          .getService(SpecialPowers.Ci.nsIXULRuntime)
                          .processType != SpecialPowers.Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
 }
 
 function testSelectAll(e) {
   // Skip mozbrowser test if we're at child process.
   if (!isChildProcess()) {
-    let eventName = testAccessibleCaret ? "mozbrowsercaretstatechanged" : "mozbrowserselectionstatechanged";
-    iframeOuter.addEventListener(eventName, function selectchangeforselectall(e) {
-      if (!e.detail.states || e.detail.states.indexOf('selectall') == 0) {
-        iframeOuter.removeEventListener(eventName, selectchangeforselectall, true);
+    iframeOuter.addEventListener("mozbrowserselectionstatechanged", function selectchangeforselectall(e) {
+      if (e.detail.states.indexOf('selectall') == 0) {
+        iframeOuter.removeEventListener("mozbrowserselectionstatechanged", selectchangeforselectall, true);
         ok(true, "got mozbrowserselectionstatechanged event." + stateMeaning);
         ok(e.detail, "event.detail is not null." + stateMeaning);
         ok(e.detail.width != 0, "event.detail.width is not zero" + stateMeaning);
         ok(e.detail.height != 0, "event.detail.height is not zero" + stateMeaning);
-        if (!testAccessibleCaret) {
-          ok(e.detail.states, "event.detail.state " + e.detail.states);
-        }
+        ok(e.detail.states, "event.detail.state " + e.detail.states);
         SimpleTest.executeSoon(function() { testCopy1(e); });
       }
     }, true);
   }
 
   mm.addMessageListener('content-focus', function messageforfocus(msg) {
     mm.removeMessageListener('content-focus', messageforfocus);
     // test selectall command, after calling this the selectionstatechanged event should be fired.

--- a/dom/ipc/jar.mn
+++ b/dom/ipc/jar.mn
@@ -2,14 +2,13 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 toolkit.jar:
         content/global/test-ipc.xul (test.xul)
         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)
         content/global/BrowserElementPanning.js (../browser-element/BrowserElementPanning.js)
 *       content/global/BrowserElementPanningAPZDisabled.js (../browser-element/BrowserElementPanningAPZDisabled.js)
         content/global/manifestMessages.js (manifestMessages.js)
         content/global/PushServiceChildPreload.js (../push/PushServiceChildPreload.js)
         content/global/preload.js (preload.js)

--- a/dom/ipc/preload.js
+++ b/dom/ipc/preload.js
@@ -98,17 +98,16 @@ const BrowserElementIsPreloaded = true;
         Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementPanningAPZDisabled.js", global);
       }
     } catch (e) {
     }
 
     Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementPanning.js", global);
   }
 
-  Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementCopyPaste.js", global);
   Services.scriptloader.loadSubScript("chrome://global/content/BrowserElementChildPreload.js", global);
 
   Services.io.getProtocolHandler("app");
   Services.io.getProtocolHandler("default");
 
   docShell.isActive = false;
   docShell.createAboutBlankContentViewer(null);
 

deleted file mode 100644
--- a/dom/webidl/CaretStateChangedEvent.webidl
+++ /dev/null
@@ -1,32 +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/.
- */
-
-enum CaretChangedReason {
-  "visibilitychange",
-  "updateposition",
-  "longpressonemptycontent",
-  "taponcaret",
-  "presscaret",
-  "releasecaret"
-};
-
-dictionary CaretStateChangedEventInit : EventInit {
-  boolean collapsed = true;
-  DOMRectReadOnly? boundingClientRect = null;
-  CaretChangedReason reason = "visibilitychange";
-  boolean caretVisible = false;
-  boolean selectionVisible = false;
-};
-
-[Constructor(DOMString type, optional CaretStateChangedEventInit eventInit),
- ChromeOnly]
-interface CaretStateChangedEvent : Event {
-  readonly attribute boolean collapsed;
-  readonly attribute DOMRectReadOnly? boundingClientRect;
-  readonly attribute CaretChangedReason reason;
-  readonly attribute boolean caretVisible;
-  readonly attribute boolean selectionVisible;
-};

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -720,17 +720,16 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'AutocompleteErrorEvent.webidl',
     'BlobEvent.webidl',
     'CallEvent.webidl',
     'CallGroupErrorEvent.webidl',
     'CameraClosedEvent.webidl',
     'CameraConfigurationEvent.webidl',
     'CameraFacesDetectedEvent.webidl',
     'CameraStateChangeEvent.webidl',
-    'CaretStateChangedEvent.webidl',
     'CFStateChangeEvent.webidl',
     'CloseEvent.webidl',
     'CSSFontFaceLoadEvent.webidl',
     'DataErrorEvent.webidl',
     'DataStoreChangeEvent.webidl',
     'DeviceLightEvent.webidl',
     'DeviceOrientationEvent.webidl',
     'DeviceProximityEvent.webidl',

--- a/layout/base/AccessibleCaretManager.cpp
+++ b/layout/base/AccessibleCaretManager.cpp
@@ -85,17 +85,16 @@ AccessibleCaretManager::OnSelectionChang
 
 void
 AccessibleCaretManager::HideCarets()
 {
   if (mFirstCaret->IsLogicallyVisible() || mSecondCaret->IsLogicallyVisible()) {
     AC_LOG("%s", __FUNCTION__);
     mFirstCaret->SetAppearance(Appearance::None);
     mSecondCaret->SetAppearance(Appearance::None);
-    DispatchCaretStateChangedEvent(CaretChangedReason::Visibilitychange);
     CancelCaretTimeoutTimer();
   }
 }
 
 void
 AccessibleCaretManager::UpdateCarets()
 {
   mCaretMode = GetCaretMode();
@@ -150,32 +149,26 @@ AccessibleCaretManager::UpdateCaretsForC
   if (!editingHost) {
     HideCarets();
     return;
   }
 
   // No need to consider whether the caret's position is out of scrollport.
   // According to the spec, we need to explicitly hide it after the scrolling is
   // ended.
-  bool oldSecondCaretVisible = mSecondCaret->IsLogicallyVisible();
-  PositionChangedResult caretResult = mFirstCaret->SetPosition(frame, offset);
+  mFirstCaret->SetPosition(frame, offset);
   mFirstCaret->SetSelectionBarEnabled(false);
   if (nsContentUtils::HasNonEmptyTextContent(
         editingHost, nsContentUtils::eRecurseIntoChildren)) {
     mFirstCaret->SetAppearance(Appearance::Normal);
     LaunchCaretTimeoutTimer();
   } else {
     mFirstCaret->SetAppearance(Appearance::NormalNotShown);
   }
   mSecondCaret->SetAppearance(Appearance::None);
-
-  if ((caretResult == PositionChangedResult::Changed ||
-      oldSecondCaretVisible) && !mActiveCaret) {
-    DispatchCaretStateChangedEvent(CaretChangedReason::Updateposition);
-  }
 }
 
 void
 AccessibleCaretManager::UpdateCaretsForSelectionMode()
 {
   AC_LOG("%s, selection: %p", __FUNCTION__, GetSelection());
 
   int32_t startOffset = 0;
@@ -216,24 +209,16 @@ AccessibleCaretManager::UpdateCaretsForS
 
   if (firstCaretResult == PositionChangedResult::Changed ||
       secondCaretResult == PositionChangedResult::Changed) {
     // Flush layout to make the carets intersection correct.
     mPresShell->FlushPendingNotifications(Flush_Layout);
   }
 
   UpdateCaretsForTilt();
-
-  if ((firstCaretResult == PositionChangedResult::Changed ||
-       secondCaretResult == PositionChangedResult::Changed ||
-       firstCaretResult == PositionChangedResult::Invisible ||
-       secondCaretResult == PositionChangedResult::Invisible) &&
-      !mActiveCaret) {
-    DispatchCaretStateChangedEvent(CaretChangedReason::Updateposition);
-  }
 }
 
 void
 AccessibleCaretManager::UpdateCaretsForTilt()
 {
   if (mFirstCaret->IsVisuallyVisible() && mSecondCaret->IsVisuallyVisible()) {
     if (mFirstCaret->Intersects(*mSecondCaret)) {
       if (mFirstCaret->LogicalPosition().x <=
@@ -263,17 +248,16 @@ AccessibleCaretManager::PressCaret(const
     mActiveCaret = mSecondCaret.get();
     SetSelectionDirection(eDirNext);
   }
 
   if (mActiveCaret) {
     mOffsetYToCaretLogicalPosition =
       mActiveCaret->LogicalPosition().y - aPoint.y;
     SetSelectionDragState(true);
-    DispatchCaretStateChangedEvent(CaretChangedReason::Presscaret);
     CancelCaretTimeoutTimer();
     rv = NS_OK;
   }
 
   return rv;
 }
 
 nsresult
@@ -290,30 +274,28 @@ AccessibleCaretManager::DragCaret(const 
 
 nsresult
 AccessibleCaretManager::ReleaseCaret()
 {
   MOZ_ASSERT(mActiveCaret);
 
   mActiveCaret = nullptr;
   SetSelectionDragState(false);
-  DispatchCaretStateChangedEvent(CaretChangedReason::Releasecaret);
   LaunchCaretTimeoutTimer();
   return NS_OK;
 }
 
 nsresult
 AccessibleCaretManager::TapCaret(const nsPoint& aPoint)
 {
   MOZ_ASSERT(GetCaretMode() != CaretMode::None);
 
   nsresult rv = NS_ERROR_FAILURE;
 
   if (GetCaretMode() == CaretMode::Cursor) {
-    DispatchCaretStateChangedEvent(CaretChangedReason::Taponcaret);
     rv = NS_OK;
   }
 
   return rv;
 }
 
 nsresult
 AccessibleCaretManager::SelectWordOrShortcut(const nsPoint& aPoint)
@@ -344,17 +326,16 @@ AccessibleCaretManager::SelectWordOrShor
   nsLayoutUtils::TransformPoint(rootFrame, ptFrame, ptInFrame);
 
   nsIContent* editingHost = ptFrame->GetContent()->GetEditingHost();
   if (ChangeFocus(ptFrame) &&
       (editingHost && !nsContentUtils::HasNonEmptyTextContent(
                          editingHost, nsContentUtils::eRecurseIntoChildren))) {
     // Content is empty. No need to select word.
     AC_LOG("%s, Cannot select word bacause content is empty", __FUNCTION__);
-    DispatchCaretStateChangedEvent(CaretChangedReason::Longpressonemptycontent);
     return NS_OK;
   }
 
   nsresult rv = SelectWord(ptFrame, ptInFrame);
   UpdateCarets();
   return rv;
 }
 
@@ -880,80 +861,9 @@ AccessibleCaretManager::LaunchCaretTimeo
 void
 AccessibleCaretManager::CancelCaretTimeoutTimer()
 {
   if (mCaretTimeoutTimer) {
     mCaretTimeoutTimer->Cancel();
   }
 }
 
-void
-AccessibleCaretManager::DispatchCaretStateChangedEvent(CaretChangedReason aReason) const
-{
-  MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
-  // Holding PresShell to prevent AccessibleCaretManager to be destroyed.
-  nsCOMPtr<nsIPresShell> presShell = mPresShell;
-  // XXX: Do we need to flush layout?
-  presShell->FlushPendingNotifications(Flush_Layout);
-  if (presShell->IsDestroying()) {
-    return;
-  }
-
-  Selection* sel = GetSelection();
-  if (!sel) {
-    return;
-  }
-
-  nsIDocument* doc = mPresShell->GetDocument();
-  MOZ_ASSERT(doc);
-
-  CaretStateChangedEventInit init;
-  init.mBubbles = true;
-
-  const nsRange* range = sel->GetAnchorFocusRange();
-  nsINode* commonAncestorNode = nullptr;
-  if (range) {
-    commonAncestorNode = range->GetCommonAncestor();
-  }
-
-  if (!commonAncestorNode) {
-    commonAncestorNode = sel->GetFrameSelection()->GetAncestorLimiter();
-  }
-
-  nsRefPtr<DOMRect> domRect = new DOMRect(ToSupports(doc));
-  nsRect rect = nsContentUtils::GetSelectionBoundingRect(sel);
-
-  nsIFrame* commonAncestorFrame = nullptr;
-  nsIFrame* rootFrame = mPresShell->GetRootFrame();
-
-  if (commonAncestorNode && commonAncestorNode->IsContent()) {
-    commonAncestorFrame = commonAncestorNode->AsContent()->GetPrimaryFrame();
-  }
-
-  if (commonAncestorFrame && rootFrame) {
-    nsLayoutUtils::TransformRect(rootFrame, commonAncestorFrame, rect);
-    nsRect clampedRect = nsLayoutUtils::ClampRectToScrollFrames(commonAncestorFrame,
-                                                                rect);
-    nsLayoutUtils::TransformRect(commonAncestorFrame, rootFrame, clampedRect);
-    domRect->SetLayoutRect(clampedRect);
-    init.mSelectionVisible = !clampedRect.IsEmpty();
-    init.mBoundingClientRect = domRect;
-  } else {
-    domRect->SetLayoutRect(rect);
-    init.mSelectionVisible = true;
-  }
-
-  init.mBoundingClientRect = domRect;
-  init.mReason = aReason;
-  init.mCollapsed = sel->IsCollapsed();
-  init.mCaretVisible = mFirstCaret->IsLogicallyVisible() ||
-                       mSecondCaret->IsLogicallyVisible();
-
-  nsRefPtr<CaretStateChangedEvent> event =
-    CaretStateChangedEvent::Constructor(doc, NS_LITERAL_STRING("mozcaretstatechanged"), init);
-
-  event->SetTrusted(true);
-  event->GetInternalNSEvent()->mFlags.mOnlyChromeDispatch = true;
-  bool ret;
-  doc->DispatchEvent(event, &ret);
-}
-
 } // namespace mozilla

--- a/layout/base/AccessibleCaretManager.h
+++ b/layout/base/AccessibleCaretManager.h
@@ -8,17 +8,16 @@
 #define AccessibleCaretManager_h
 
 #include "nsCOMPtr.h"
 #include "nsCoord.h"
 #include "nsIFrame.h"
 #include "nsISelectionListener.h"
 #include "nsRefPtr.h"
 #include "nsWeakReference.h"
-#include "mozilla/dom/CaretStateChangedEvent.h"
 #include "mozilla/EventForwards.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/WeakPtr.h"
 
 class nsFrameSelection;
 class nsIContent;
 class nsIPresShell;
 struct nsPoint;
@@ -128,20 +127,16 @@ protected:
   nsresult DragCaretInternal(const nsPoint& aPoint);
   nsPoint AdjustDragBoundary(const nsPoint& aPoint) const;
   void ClearMaintainedSelection() const;
 
   dom::Selection* GetSelection() const;
   already_AddRefed<nsFrameSelection> GetFrameSelection() const;
   nsIContent* GetFocusedContent() const;
 
-  // This function will call FlushPendingNotifications. So caller must ensure
-  // everything exists after calling this method.
-  void DispatchCaretStateChangedEvent(dom::CaretChangedReason aReason) const;
-
   // If we're dragging the first caret, we do not want to drag it over the
   // previous character of the second caret. Same as the second caret. So we
   // check if content offset exceeds the previous/next character of second/first
   // caret base the active caret.
   bool CompareRangeWithContentOffset(nsIFrame::ContentOffsets& aOffsets);
 
   // Timeout in milliseconds to hide the AccessibleCaret under cursor mode while
   // no one touches it.