Fix cast from video player by using DriveApiUrlGenerator to generate URL

chrome/browser/chromeos/extensions/file_manager/private_api_drive.h

 // 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.
 //
 // This file provides Drive specific API functions.
 
 #ifndef CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_PRIVATE_API_DRIVE_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_PRIVATE_API_DRIVE_H_
 
 #include <string>
@@ skipping 222 matching lines @@
 
   void OnGetResourceEntry(drive::FileError error,
                           scoped_ptr<drive::ResourceEntry> entry);
 
   // Callback with an |access_token|, called by
   // drive::DriveReadonlyTokenFetcher.
   void OnTokenFetched(google_apis::DriveApiErrorCode code,
                       const std::string& access_token);
 
  private:
-  std::string download_url_;
+  GURL download_url_;
   scoped_ptr<google_apis::AuthService> auth_service_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_PRIVATE_API_DRIVE_H_