ozone: gbm: Add overlay support

ui/ozone/platform/dri/scanout_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_SCANOUT_SURFACE_H_
 #define UI_OZONE_PLATFORM_DRI_SCANOUT_SURFACE_H_
 
 #include <stdint.h>
 
 namespace gfx {
@@ skipping 41 matching lines @@
 class ScanoutSurface {
  public:
   virtual ~ScanoutSurface() {}
 
   // Used to allocate all necessary buffers for this surface. If the
   // initialization succeeds, the device is ready to be used for drawing
   // operations.
   // Returns true if the initialization is successful, false otherwise.
   virtual bool Initialize() = 0;
 
+  // Prepare the surface to be displayed.
+  virtual void PreSwapBuffers() = 0;
+
   // Swaps the back buffer with the front buffer.
   virtual void SwapBuffers() = 0;
 
   // Returns the ID of the current backbuffer.
   virtual uint32_t GetFramebufferId() const = 0;
 
   // Returns the handle of the current backbuffer.
   virtual uint32_t GetHandle() const = 0;
 
   // Returns the surface size.
   virtual gfx::Size Size() const = 0;
 };
 
 class ScanoutSurfaceGenerator {
  public:
   virtual ~ScanoutSurfaceGenerator() {}
 
   virtual ScanoutSurface* Create(const gfx::Size& size) = 0;
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_SCANOUT_SURFACE_H_