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

chrome/test/data/extensions/api_test/filebrowser_component/main.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 component extension test does the following:
 
 1. Creates an abc and log file on the local file system with some random text.
 2. Finds a registered task (file item context menu) for abc file and invokes it
    with url of the test file.
@@ skipping 60 matching lines @@
 var TestRunner = function(expectations) {
   this.expectations_ = expectations;
   this.fileCreator_ = new TestFileCreator("tmp", true /* shouldRandomize */);
   this.listener_ = this.onHandlerRequest_.bind(this);
 };
 
 // Starts the test.
 TestRunner.prototype.runTest = function() {
   // Get local FS, create dir with a file in it.
   console.log('Requesting local file system...');
-  chrome.extension.onMessageExternal.addListener(this.listener_);
+  chrome.runtime.onMessageExternal.addListener(this.listener_);
   chrome.fileBrowserPrivate.requestLocalFileSystem(
       this.onFileSystemFetched_.bind(this));
 };
 
 TestRunner.prototype.onFileSystemFetched_ = function(fs) {
   if (!fs) {
     this.errorCallback_(chrome.extensions.lastError);
     return;
   }
 
@@ skipping 92 matching lines @@
   chrome.test.fail(message);
 };
 
 // Listens for the request from the filesystem_handler extension. When the
 // event is received, it verifies it and stops listening for further events.
 TestRunner.prototype.onHandlerRequest_ =
     function(request, sender, sendResponse) {
   this.expectations_.verifyHandlerRequest(
       request,
       this.verifyRequestCallback_.bind(this, sendResponse));
-  chrome.extension.onMessageExternal.removeListener(this.listener_);
+  chrome.runtime.onMessageExternal.removeListener(this.listener_);
 };
 
 TestRunner.prototype.verifyRequestCallback_ = function(sendResponse, error) {
   if (!error) {
     sendResponse({success: true});
     this.fileCreator_.cleanupAndEndTest(this.reportSuccess_.bind(this),
                                         this.reportFail_.bind(this,
                                                               cleanupError));
   } else {
     sendResponse({success: false});
     this.errorCallback_(error);
   }
 };