Use a direct include of strings headers in extensions/, google_apis/, gpu/.

google_apis/gaia/gaia_auth_fetcher_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 GaiaAuthFetcher.
 // Originally ported from GoogleAuthenticator tests.
 
 #include <string>
 
 #include "base/json/json_reader.h"
 #include "base/message_loop.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/values.h"
 #include "chrome/test/base/testing_profile.h"
 #include "google_apis/gaia/gaia_auth_consumer.h"
 #include "google_apis/gaia/gaia_auth_fetcher.h"
 #include "google_apis/gaia/gaia_urls.h"
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "google_apis/gaia/mock_url_fetcher_factory.h"
 #include "google_apis/google_api_keys.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/load_flags.h"
@@ skipping 782 matching lines @@
       .Times(1);
 
   GaiaAuthFetcher auth(&consumer, std::string(),
       profile_.GetRequestContext());
   net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, 0);
   MockFetcher mock_fetcher(
       oauth_login_gurl_, status, net::HTTP_OK, cookies_, data,
       net::URLFetcher::GET, &auth);
   auth.OnURLFetchComplete(&mock_fetcher);
 }