[Ozone-DRI] Convert HardwareDisplayController to use scanout buffers

ui/ozone/platform/dri/gbm_surface.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_SURFACE_H_
 #define UI_OZONE_PLATFORM_DRI_GBM_SURFACE_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gfx/geometry/size.h"
@@ skipping 10 matching lines @@
 class GbmBufferBase;
 
 // Implement the ScanoutSurface interface on top of GBM (Generic Buffer
 // Manager). GBM provides generic access to hardware accelerated surfaces which
 // can be used in association with EGL to provide accelerated drawing.
 class GbmSurface : public ScanoutSurface {
  public:
   GbmSurface(gbm_device* device, DriWrapper* dri, const gfx::Size& size);
   virtual ~GbmSurface();
 
+  scoped_refptr<GbmBufferBase> backbuffer() const {
+    return buffers_[front_buffer_ ^ 1];
+  }
+
   // 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;
 
   gbm_surface* native_surface() { return native_surface_; };
 
@@ skipping 19 matching lines @@
   // before an actual window is created and draws. So, we create a dumb buffer
   // for this purpose.
   scoped_refptr<DriBuffer> dumb_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(GbmSurface);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_GBM_SURFACE_H_