Coverity: Fix pass-by-value.

chrome/common/net/gaia/oauth2_mint_token_fetcher.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_COMMON_NET_GAIA_OAUTH2_MINT_TOKEN_FETCHER_H_
 #define CHROME_COMMON_NET_GAIA_OAUTH2_MINT_TOKEN_FETCHER_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 51 matching lines @@
     INITIAL,
     MINT_TOKEN_STARTED,
     MINT_TOKEN_DONE,
     ERROR_STATE,
   };
 
   // Helper methods for the flow.
   void StartMintToken();
   void EndMintToken(const content::URLFetcher* source);
 
-  // Helper mehtods for reporting back results.
+  // Helper methods for reporting back results.
   void OnMintTokenSuccess(const std::string& access_token);
-  void OnMintTokenFailure(GoogleServiceAuthError error);
+  void OnMintTokenFailure(const GoogleServiceAuthError& error);
 
   // Other helpers.
   static GURL MakeMintTokenUrl();
   static std::string MakeMintTokenHeader(const std::string& access_token);
   static std::string MakeMintTokenBody(const std::string& client_id,
                                        const std::vector<std::string>& scopes,
                                        const std::string& origin);
   static bool ParseMintTokenResponse(const content::URLFetcher* source,
                                      std::string* access_token);
 
@@ skipping 11 matching lines @@
   std::string origin_;
 
   friend class OAuth2MintTokenFetcherTest;
   FRIEND_TEST_ALL_PREFIXES(OAuth2MintTokenFetcherTest,
                            ParseMintTokenResponse);
 
   DISALLOW_COPY_AND_ASSIGN(OAuth2MintTokenFetcher);
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_OAUTH2_MINT_TOKEN_FETCHER_H_