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

gpu/config/gpu_info_collector_mac.mm

 // 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 "gpu/config/gpu_info_collector.h"
 
 #include <vector>
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/string_number_conversions.h"
-#include "base/string_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
+#include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_interface.h"
 
 #import <Cocoa/Cocoa.h>
 #import <Foundation/Foundation.h>
 #import <IOKit/IOKitLib.h>
 
@@ skipping 184 matching lines @@
   gpu_info->driver_version = gl_version_string.substr(pos + 1);
   return true;
 }
 
 void MergeGPUInfo(GPUInfo* basic_gpu_info,
                   const GPUInfo& context_gpu_info) {
   MergeGPUInfoGL(basic_gpu_info, context_gpu_info);
 }
 
 }  // namespace gpu