Changed GpuVSyncProvider to implement gfx::VSyncProvider

ui/gl/vsync_provider_win.h

 // Copyright 2015 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 UI_GL_VSYNC_PROVIDER_WIN_H_
+#define UI_GL_VSYNC_PROVIDER_WIN_H_
+
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/vsync_provider.h"
 #include "ui/gl/gl_export.h"
 
 namespace gl {
 
 class GL_EXPORT VSyncProviderWin : public gfx::VSyncProvider {
  public:
   explicit VSyncProviderWin(gfx::AcceleratedWidget window);
   ~VSyncProviderWin() override;
 
   static void InitializeOneOff();
 
   // gfx::VSyncProvider overrides;
   void GetVSyncParameters(const UpdateVSyncCallback& callback) override;
 
  private:
   gfx::AcceleratedWidget window_;
 
   DISALLOW_COPY_AND_ASSIGN(VSyncProviderWin);
 };
 
 }  // namespace gl
+
+#endif  // UI_GL_VSYNC_PROVIDER_WIN_H_