ozone: gbm: Add overlay support

ui/ozone/platform/dri/gbm_buffer.h

 // Copyright 2014 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_OZONE_PLATFORM_DRI_GBM_BUFFER_H_
 #define UI_OZONE_PLATFORM_DRI_GBM_BUFFER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/gfx/geometry/size.h"
+#include "ui/ozone/platform/dri/scanout_surface.h"
 #include "ui/ozone/public/native_pixmap.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 
 struct gbm_bo;
 struct gbm_device;
 
 namespace ui {
 
 class DriWrapper;
 
-class GbmBuffer : public NativePixmap {
+class GbmBuffer : public NativePixmap, public ScanoutSurface {
  public:
   GbmBuffer(gbm_device* device, DriWrapper* dri, const gfx::Size& size);
 
   bool InitializeBuffer(SurfaceFactoryOzone::BufferFormat format, bool scanout);
 
   // NativePixmap:
   virtual void* GetEGLClientBuffer() OVERRIDE;
   virtual int GetDmaBufFd() OVERRIDE;
 
+  // ScanoutSurface:
+  virtual bool Initialize() OVERRIDE;
+  virtual uint32_t GetFramebufferId() const OVERRIDE;
+  virtual uint32_t GetHandle() const OVERRIDE;
+  virtual gfx::Size Size() const OVERRIDE;
+  virtual void PreSwapBuffers() OVERRIDE;
+  virtual void SwapBuffers() OVERRIDE;
+
  protected:
   virtual ~GbmBuffer();
 
  private:
   gbm_device* gbm_device_;
   gbm_bo* bo_;
 
   uint32_t handle_;
   uint32_t framebuffer_;
 
   DriWrapper* dri_;
 
   gfx::Size size_;
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_GBM_BUFFER_H_