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

gpu/command_buffer/service/context_group.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 "gpu/command_buffer/service/context_group.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/command_line.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/sys_info.h"
 #include "gpu/command_buffer/common/id_allocator.h"
 #include "gpu/command_buffer/service/buffer_manager.h"
 #include "gpu/command_buffer/service/framebuffer_manager.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
 #include "gpu/command_buffer/service/image_manager.h"
 #include "gpu/command_buffer/service/mailbox_manager.h"
 #include "gpu/command_buffer/service/memory_tracking.h"
 #include "gpu/command_buffer/service/program_manager.h"
@@ skipping 345 matching lines @@
     GLenum pname, GLint min_required, uint32* v) {
   uint32 value = 0;
   GetIntegerv(pname, &value);
   bool result = CheckGLFeatureU(min_required, &value);
   *v = value;
   return result;
 }
 
 }  // namespace gles2
 }  // namespace gpu