Use a direct include of strings headers in chrome/browser/r*-s*/.

chrome/browser/spellchecker/spelling_service_client_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.
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/spellchecker/spelling_service_client.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/spellcheck_result.h"
 #include "chrome/test/base/testing_profile.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 360 matching lines @@
     EXPECT_FALSE(client_.IsAvailable(&profile_, kSpellcheck));
   }
 }
 
 // Verify that an error in JSON response from spelling service will result in
 // ParseResponse returning false.
 TEST_F(SpellingServiceClientTest, ResponseErrorTest) {
   EXPECT_TRUE(client_.ParseResponseSuccess("{\"result\": {}}"));
   EXPECT_FALSE(client_.ParseResponseSuccess("{\"error\": {}}"));
 }