Add the "virtual" keyword on method overrides that are missing it.

chrome/service/gaia/service_gaia_authenticator.h

 // Copyright (c) 2010 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_SERVICE_GAIA_SERVICE_GAIA_AUTHENTICATOR_H_
 #define CHROME_SERVICE_GAIA_SERVICE_GAIA_AUTHENTICATOR_H_
 #pragma once
 
 #include <string>
 
@@ skipping 13 matching lines @@
       public URLFetcher::Delegate,
       public gaia::GaiaAuthenticator {
  public:
   ServiceGaiaAuthenticator(const std::string& user_agent,
                            const std::string& service_id,
                            const std::string& gaia_url,
                            base::MessageLoopProxy* io_message_loop_proxy);
   ~ServiceGaiaAuthenticator();
 
   // URLFetcher::Delegate implementation.
-  void OnURLFetchComplete(const URLFetcher *source, const GURL &url,
-                          const URLRequestStatus &status, int response_code,
-                          const ResponseCookies &cookies,
-                          const std::string &data);
+  virtual void OnURLFetchComplete(const URLFetcher *source,
+                                  const GURL &url,
+                                  const URLRequestStatus &status,
+                                  int response_code,
+                                  const ResponseCookies &cookies,
+                                  const std::string &data);
 
  protected:
   // GaiaAuthenticator overrides.
   virtual bool Post(const GURL& url, const std::string& post_body,
                     unsigned long* response_code, std::string* response_body);
   virtual int GetBackoffDelaySeconds(int current_backoff_delay);
 
  private:
   void DoPost(const GURL& post_url, const std::string& post_body);
 
   base::WaitableEvent http_post_completed_;
   scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
   int http_response_code_;
   std::string response_data_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceGaiaAuthenticator);
 };
 
 #endif  // CHROME_SERVICE_GAIA_SERVICE_GAIA_AUTHENTICATOR_H_