--- a/dom/browser-element/BrowserElementChildPreload.js
+++ b/dom/browser-element/BrowserElementChildPreload.js
@@ -63,25 +63,16 @@ var CERTIFICATE_ERROR_PAGE_PREF = 'secur
 
 const OBSERVED_EVENTS = [
   'xpcom-shutdown',
   'audio-playback',
   'activity-done',
   'invalid-widget'
 ];
 
-const COMMAND_MAP = {
-  'cut': 'cmd_cut',
-  'copy': 'cmd_copyAndCollapseToEnd',
-  'copyImage': 'cmd_copyImage',
-  'copyLink': 'cmd_copyLink',
-  'paste': 'cmd_paste',
-  'selectall': 'cmd_selectAll'
-};
-
 /**
  * The BrowserElementChild implements one half of <iframe mozbrowser>.
  * (The other half is, unsurprisingly, BrowserElementParent.)
  *
  * This script is injected into an <iframe mozbrowser> via
  * nsIMessageManager::LoadFrameScript().
  *
  * Our job here is to listen for events within this frame and bubble them up to
@@ -273,17 +264,16 @@ BrowserElementChild.prototype = {
       "unblock-modal-prompt": this._recvStopWaiting,
       "fire-ctx-callback": this._recvFireCtxCallback,
       "owner-visibility-change": this._recvOwnerVisibilityChange,
       "entered-fullscreen": this._recvEnteredFullscreen,
       "exit-fullscreen": this._recvExitFullscreen.bind(this),
       "activate-next-paint-listener": this._activateNextPaintListener.bind(this),
       "set-input-method-active": this._recvSetInputMethodActive.bind(this),
       "deactivate-next-paint-listener": this._deactivateNextPaintListener.bind(this),
-      "do-command": this._recvDoCommand,
       "find-all": this._recvFindAll.bind(this),
       "find-next": this._recvFindNext.bind(this),
       "clear-match": this._recvClearMatch.bind(this),
       "execute-script": this._recvExecuteScript,
       "get-audio-channel-volume": this._recvGetAudioChannelVolume,
       "set-audio-channel-volume": this._recvSetAudioChannelVolume,
       "get-audio-channel-muted": this._recvGetAudioChannelMuted,
       "set-audio-channel-muted": this._recvSetAudioChannelMuted,
@@ -402,25 +392,16 @@ BrowserElementChild.prototype = {
 
     if (args.promptType == 'prompt' ||
         args.promptType == 'confirm' ||
         args.promptType == 'custom-prompt') {
       return returnValue;
     }
   },
 
-  _isCommandEnabled: function(cmd) {
-    let command = COMMAND_MAP[cmd];
-    if (!command) {
-      return false;
-    }
-
-    return docShell.isCommandEnabled(command);
-  },
-
   /**
    * Spin in a nested event loop until we receive a unblock-modal-prompt message for
    * this window.
    */
   _waitForResult: function(win) {
     debug("_waitForResult(" + win + ")");
     let utils = win.QueryInterface(Ci.nsIInterfaceRequestor)
                    .getInterface(Ci.nsIDOMWindowUtils);
@@ -1191,24 +1172,26 @@ BrowserElementChild.prototype = {
         successRv: blob
       });
     }, mimeType);
   },
 
   _recvFireCtxCallback: function(data) {
     debug("Received fireCtxCallback message: (" + data.json.menuitem + ")");
 
+    let doCommandIfEnabled = (command) => {
+      if (docShell.isCommandEnabled(command)) {
+        docShell.doCommand(command);
+      }
+    };
+
     if (data.json.menuitem == 'copy-image') {
-      // Set command
-      data.json.command = 'copyImage';
-      this._recvDoCommand(data);
+      doCommandIfEnabled('cmd_copyImage');
     } else if (data.json.menuitem == 'copy-link') {
-      // Set command
-      data.json.command = 'copyLink';
-      this._recvDoCommand(data);
+      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");
     }
   },
@@ -1377,22 +1360,16 @@ BrowserElementChild.prototype = {
     let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
     webNav.stop(webNav.STOP_NETWORK);
   },
 
   _recvZoom: function(data) {
     docShell.contentViewer.fullZoom = data.json.zoom;
   },
 
-  _recvDoCommand: function(data) {
-    if (this._isCommandEnabled(data.json.command)) {
-      docShell.doCommand(COMMAND_MAP[data.json.command]);
-    }
-  },
-
   _recvGetAudioChannelVolume: function(data) {
     debug("Received getAudioChannelVolume message: (" + data.json.id + ")");
 
     let volume = acs.getAudioChannelVolume(content,
                                            data.json.args.audioChannel);
     sendAsyncMsg('got-audio-channel-volume', {
       id: data.json.id, successRv: volume
     });

--- a/dom/browser-element/BrowserElementCopyPaste.js
+++ b/dom/browser-element/BrowserElementCopyPaste.js
@@ -25,17 +25,17 @@ var CopyPasteAssistent = {
                      /* 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]);
+          docShell.doCommand(this.COMMAND_MAP[e.data.command]);
         }
         break;
     }
   },
 
   _isCommandEnabled: function(cmd) {
     let command = this.COMMAND_MAP[cmd];
     if (!command) {

--- a/dom/browser-element/BrowserElementParent.js
+++ b/dom/browser-element/BrowserElementParent.js
@@ -245,17 +245,16 @@ function BrowserElementParent() {
   this._domRequestReady = false;
   this._pendingAPICalls = [];
   this._pendingDOMRequests = {};
   this._pendingSetInputMethodActive = [];
   this._nextPaintListeners = [];
   this._pendingDOMFullscreen = false;
 
   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);
   Services.obs.addObserver(this, 'back-docommand', /* ownsWeak = */ true);
 
   this.proxyCallHandler = new BrowserElementParentProxyCallHandler();
 }
 
 BrowserElementParent.prototype = {
 
@@ -1290,21 +1289,16 @@ BrowserElementParent.prototype = {
 
   observe: function(subject, topic, data) {
     switch(topic) {
     case 'oop-frameloader-crashed':
       if (this._isAlive() && subject == this._frameLoader) {
         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;
     case 'back-docommand':
       if (this._isAlive() && this._frameLoader.visible) {
           this.goBack();

--- a/dom/browser-element/mochitest/browserElement_CopyPaste.js
+++ b/dom/browser-element/mochitest/browserElement_CopyPaste.js
@@ -81,18 +81,24 @@ function runTest() {
       iframeInner = iframeOuter;
       mm = SpecialPowers.getBrowserFrameMessageManager(iframeInner);
       dispatchTest(e);
     }
   });
 }
 
 function doCommand(cmd) {
-  Services.obs.notifyObservers({wrappedJSObject: SpecialPowers.unwrap(iframeInner)},
-                               'copypaste-docommand', cmd);
+  var COMMAND_MAP = {
+    'cut': 'cmd_cut',
+    'copy': 'cmd_copyAndCollapseToEnd',
+    'paste': 'cmd_paste',
+    'selectall': 'cmd_selectAll'
+  };
+  var script = 'data:,docShell.doCommand("' + COMMAND_MAP[cmd] + '");';
+  mm.loadFrameScript(script, false);
 }
 
 function dispatchTest(e) {
   iframeInner.addEventListener("mozbrowserloadend", function onloadend2(e) {
     iframeInner.removeEventListener("mozbrowserloadend", onloadend2);
     iframeInner.focus();
     SimpleTest.executeSoon(function() { testSelectAll(e); });
   });