Use a direct include of strings headers in chrome/test/.

chrome/test/automation/window_proxy.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_TEST_AUTOMATION_WINDOW_PROXY_H__
 #define CHROME_TEST_AUTOMATION_WINDOW_PROXY_H__
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "base/threading/thread.h"
 #include "chrome/test/automation/automation_handle_tracker.h"
 
 class BrowserProxy;
 class WindowProxy;
 
 namespace gfx {
 class Rect;
 }
 
@@ skipping 18 matching lines @@
   // bounds was successful.
   bool SetBounds(const gfx::Rect& bounds);
 
  protected:
   virtual ~WindowProxy() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(WindowProxy);
 };
 
 #endif  // CHROME_TEST_AUTOMATION_WINDOW_PROXY_H__