Rewrite std::string("") to std::string(), Linux edition.

google_apis/gaia/oauth2_mint_token_flow_unittest.cc

 // 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.
 //
 // A complete set of unit tests for OAuth2MintTokenFlow.
 
 #include <string>
 #include <vector>
 
 #include "base/json/json_reader.h"
@@ skipping 254 matching lines @@
     EXPECT_TRUE(OAuth2MintTokenFlow::ParseIssueAdviceResponse(
         json.get(), &ia));
     IssueAdviceInfo ia_expected(CreateIssueAdvice());
     EXPECT_EQ(ia_expected, ia);
   }
 }
 
 TEST_F(OAuth2MintTokenFlowTest, ProcessApiCallSuccess) {
   {  // No body.
     TestURLFetcher url_fetcher(1, GURL("http://www.google.com"), NULL);
-    url_fetcher.SetResponseString("");
+    url_fetcher.SetResponseString(std::string());
     CreateFlow(OAuth2MintTokenFlow::MODE_MINT_TOKEN_NO_FORCE);
     EXPECT_CALL(delegate_, OnMintTokenFailure(_));
     flow_->ProcessApiCallSuccess(&url_fetcher);
   }
   {  // Bad json.
     TestURLFetcher url_fetcher(1, GURL("http://www.google.com"), NULL);
     url_fetcher.SetResponseString("foo");
     CreateFlow(OAuth2MintTokenFlow::MODE_MINT_TOKEN_NO_FORCE);
     EXPECT_CALL(delegate_, OnMintTokenFailure(_));
     flow_->ProcessApiCallSuccess(&url_fetcher);
@@ skipping 62 matching lines @@
   }
 
   {  // Non-null delegate.
     GoogleServiceAuthError error(
         GoogleServiceAuthError::FromConnectionError(101));
     CreateFlow(OAuth2MintTokenFlow::MODE_MINT_TOKEN_NO_FORCE);
     EXPECT_CALL(delegate_, OnMintTokenFailure(error));
     flow_->ProcessMintAccessTokenFailure(error);
   }
 }