Correctly invoke the exported cast functions.

chrome/browser/ui/ash/cast_config_delegate_chromeos.cc

Index: chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc b/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
index b2196e97705e01ef346d7214d2696d8168ced72f..c97aeea96c7f273993f472b462b72df8ccb99d40 100644
--- a/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
@@ -127,26 +127,32 @@ bool CastConfigDelegateChromeos::HasCastExtension() const {
 
 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() {