Video Player: Install the cast API extension if it is not installed.

chrome/common/extensions/api/file_browser_private.idl

 // Copyright 2013 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.
 
 // fileBrowserPrivate API.
 // This is a private API used by the file browser of ChromeOS.
 [platforms=("chromeos"),
  implemented_in="chrome/browser/chromeos/extensions/file_manager/file_browser_private_api_functions.h"]
 namespace fileBrowserPrivate {
 // Type of the mounted volume.
@@ skipping 767 matching lines @@
 
   // Requests to share drive files.
   // |url| URL of a file to be shared.
   // |shareType| Type of access that is getting granted.
   static void requestDriveShare(DOMString url,
                                 DriveShareType shareType,
                                 SimpleCallback callback);
 
   // Requests to install a webstore item.
   // |item_id| The id of the item to install.
+  // |silentInstallation| False to show installation prompt. True not to show.
   // |callback|
-  static void installWebstoreItem(DOMString item_id,
+  static void installWebstoreItem(DOMString itemId,
+                                  boolean silentInstallation,
                                   SimpleCallback callback);
 
   // Obtains a list of profiles that are logged-in.
   static void getProfiles(GetProfilesCallback callback);
 
   // Moves the window to other user's desktop.
   static void visitDesktop(DOMString profileId,
                            optional SimpleCallback callback);
 
   // Opens inspector window.
@@ skipping 19 matching lines @@
   static void onDriveSyncError(DriveSyncErrorEvent event);
 
   // Dispatched when a profile is added.
   static void onProfileAdded();
 
   // Dispatched when any window moves another desktop.
   // TODO(hirono): Add information which window is moved.
   static void onDesktopChanged();
 };
 };