Hold URLRequestContextGetter by scoped_refptr in Drive related code.

chrome/browser/google_apis/auth_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_H_
 #define CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 47 matching lines @@
   void OnHandleRefreshToken(bool has_refresh_token);
 
   // Called when authentication request from StartAuthentication() is
   // completed.
   void OnAuthCompleted(const AuthStatusCallback& callback,
                        GDataErrorCode error,
                        const std::string& access_token);
 
   OAuth2TokenService* oauth2_token_service_;
   std::string account_id_;
-  net::URLRequestContextGetter* url_request_context_getter_;  // Not owned.
+  scoped_refptr<net::URLRequestContextGetter> url_request_context_getter_;
   bool has_refresh_token_;
   std::string access_token_;
   std::vector<std::string> scopes_;
   ObserverList<AuthServiceObserver> observers_;
   base::ThreadChecker thread_checker_;
 
   // Note: This should remain the last member so it'll be destroyed and
   // invalidate its weak pointers before any other members are destroyed.
   base::WeakPtrFactory<AuthService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AuthService);
 };
 
 }  // namespace google_apis
 
 #endif  // CHROME_BROWSER_GOOGLE_APIS_AUTH_SERVICE_H_