Make CEF compliant with Google/Chromium style (issue #473).

- Add a new check_style tool based on Google's cpplint that can be used to verify compliance of pending changes and specific files/directories.
- Update existing CEF source code to be compliant with the style requirements.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@463 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser_drag_delegate_win.h

@@ -3,10 +3,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef _BROWSER_DRAG_DELEGATE_WIN_H
-#define _BROWSER_DRAG_DELEGATE_WIN_H
+#ifndef CEF_LIBCEF_BROWSER_DRAG_DELEGATE_WIN_H_
+#define CEF_LIBCEF_BROWSER_DRAG_DELEGATE_WIN_H_
 #pragma once
 
+#include <string>
+
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/platform_thread.h"
@@ -99,4 +101,4 @@ class BrowserDragDelegate
 };
 
 
-#endif  // _BROWSER_DRAG_DELEGATE_WIN_H
+#endif  // CEF_LIBCEF_BROWSER_DRAG_DELEGATE_WIN_H_