Use a direct include of strings headers in chrome/browser/chromeos/.

chrome/browser/chromeos/drive/file_system_proxy.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 "chrome/browser/chromeos/drive/file_system_proxy.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/platform_file.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/drive/drive.pb.h"
 #include "chrome/browser/chromeos/drive/file_system_interface.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/drive/webkit_file_stream_reader_impl.h"
 #include "chrome/browser/google_apis/task_util.h"
 #include "chrome/browser/google_apis/time_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/browser/blob/file_stream_reader.h"
@@ skipping 840 matching lines @@
                      base::Bind(&EmitDebugLogForCloseFile,
                                 virtual_path))));
 }
 
 FileSystemInterface* FileSystemProxy::GetFileSystemOnUIThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   return file_system_;
 }
 
 }  // namespace drive