Coverity fix: Big parameter passed by value

chrome/common/net/gaia/oauth2_access_token_fetcher.h

 // Copyright (c) 2011 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_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_FETCHER_H_
 #define CHROME_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_FETCHER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 58 matching lines @@
     GET_ACCESS_TOKEN_DONE,
     ERROR_STATE,
   };
 
   // Helper methods for the flow.
   void StartGetAccessToken();
   void EndGetAccessToken(const content::URLFetcher* source);
 
   // Helper mehtods for reporting back results.
   void OnGetTokenSuccess(const std::string& access_token);
-  void OnGetTokenFailure(GoogleServiceAuthError error);
+  void OnGetTokenFailure(const GoogleServiceAuthError& error);
 
   // Other helpers.
   static GURL MakeGetAccessTokenUrl();
   static std::string MakeGetAccessTokenBody(
       const std::string& client_id,
       const std::string& client_secret,
       const std::string& refresh_token,
       const std::vector<std::string>& scopes);
   static bool ParseGetAccessTokenResponse(const content::URLFetcher* source,
                                           std::string* access_token);
@@ skipping 13 matching lines @@
   friend class OAuth2AccessTokenFetcherTest;
   FRIEND_TEST_ALL_PREFIXES(OAuth2AccessTokenFetcherTest,
                            ParseGetAccessTokenResponse);
   FRIEND_TEST_ALL_PREFIXES(OAuth2AccessTokenFetcherTest,
                            MakeGetAccessTokenBody);
 
   DISALLOW_COPY_AND_ASSIGN(OAuth2AccessTokenFetcher);
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_FETCHER_H_