Update references to the extension messaging APIs to point to the "runtime"

chrome/renderer/resources/extensions/miscellaneous_bindings.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This contains unprivileged javascript APIs for extensions and apps.  It
 // can be loaded by any extension-related context, such as content scripts or
 // background pages. See user_script_slave.cc for script that is loaded by
 // content scripts only.
 
   require('json_schema');
@@ skipping 237 matching lines @@
   chromeHidden.Port.dispatchOnMessage = function(msg, portId) {
     var port = ports[portId];
     if (port) {
       if (msg) {
         msg = chromeHidden.JSON.parse(msg);
       }
       port.onMessage.dispatch(msg, port);
     }
   };
 
-  // Shared implementation used by tabs.sendMessage and extension.sendMessage.
+  // Shared implementation used by tabs.sendMessage and runtime.sendMessage.
   chromeHidden.Port.sendMessageImpl = function(port, request,
                                                responseCallback) {
     if (port.name != chromeHidden.kNativeMessageChannel)
       port.postMessage(request);
 
     if (port.name == chromeHidden.kMessageChannel && !responseCallback) {
       // TODO(mpcomplete): Do this for the old sendRequest API too, after
       // verifying it doesn't break anything.
       // Go ahead and disconnect immediately if the sender is not expecting
       // a response.
@@ skipping 44 matching lines @@
     var targetId = null;
     if (lastArg >= 0)
       targetId = args[lastArg--];
 
     if (lastArg != -1)
       throw new Error('Invalid arguments to ' + functionName + '.');
     return [targetId, request, responseCallback];
   }
 
 exports.sendMessageUpdateArguments = sendMessageUpdateArguments;