Correctly invoke the exported cast functions.

chrome/browser/ui/ash/cast_config_delegate_chromeos.cc

 // Copyright 2015 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.
 
 #include "chrome/browser/ui/ash/cast_config_delegate_chromeos.h"
 
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 109 matching lines @@
 
 CastConfigDelegateChromeos::~CastConfigDelegateChromeos() {
 }
 
 bool CastConfigDelegateChromeos::HasCastExtension() const {
   return FindCastExtension() != nullptr;
 }
 
 void CastConfigDelegateChromeos::GetReceiversAndActivities(
     const ReceiversAndActivitesCallback& callback) {
+  // The extension API methods are exported to the global namespace, not to
+  // backgroundSetup, even though they are conceptually methods on
+  // backgroundSetup. This means that to invoke the exported methods, we
+  // have to manually bind the this argument using call (versus doing the
+  // more expected backgroundSetup.getMirrorCapable...()).

[achuithb, 2015/06/05 23:46:49]

Hmm, how about something more along the lines of:

// The methods in backgroundSetup are renamed during minification, so we have to
bind the exported global API methods to backgroundSetup using call().  

The purpose of the comment is simply to explain why we have to use weird syntax.
We can probably just duplicate the comment since it's not too long.

   ExecuteJavaScriptWithCallback(
-      "backgroundSetup.getMirrorCapableReceiversAndActivities();",
+      "getMirrorCapableReceiversAndActivities.call(backgroundSetup);",
       base::Bind(&GetReceiversAndActivitiesCallback, callback));
 }
 
 void CastConfigDelegateChromeos::CastToReceiver(
     const std::string& receiver_id) {
-  ExecuteJavaScript("backgroundSetup.launchDesktopMirroring('" + receiver_id +
-                    "');");
+  // See comment in GetReceiversAndActivities.
+  ExecuteJavaScript("launchDesktopMirroring.call(backgroundSetup, '" +
+                    receiver_id + "');");
 }
 
 void CastConfigDelegateChromeos::StopCasting() {
-  ExecuteJavaScript("backgroundSetup.stopMirroring('user-stop')");
-
+  // See comment in GetReceiversAndActivities.
   // TODO(jdufault): Remove this after the beta/release versions of the
   // cast extension have been updated so that they properly export the
   // stopMirroring function. For now, we try to invoke all of the other
   // names that the function goes by. See crbug.com/489929.
-  ExecuteJavaScript("backgroundSetup.stopCastMirroring('user-stop');");
   ExecuteJavaScript("backgroundSetup.Qu('user-stop');");
+  ExecuteJavaScript("stopCastMirroring.call(backgroundSetup, 'user-stop');");
+  ExecuteJavaScript("stopMirroring.call(backgroundSetup, 'user-stop');");
 }
 
 void CastConfigDelegateChromeos::LaunchCastOptions() {
   chrome::NavigateParams params(
       ProfileManager::GetActiveUserProfile(),
       FindCastExtension()->GetResourceURL("options.html"),
       ui::PAGE_TRANSITION_LINK);
   params.disposition = NEW_FOREGROUND_TAB;
   params.window_action = chrome::NavigateParams::SHOW_WINDOW;
   chrome::Navigate(&params);
 }
 
 }  // namespace chromeos