gpu: Empty swaps for surfaceless output surfaces.

components/display_compositor/buffer_queue.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 COMPONENTS_DISPLAY_COMPOSITOR_BUFFER_QUEUE_H_
 #define COMPONENTS_DISPLAY_COMPOSITOR_BUFFER_QUEUE_H_
 
 #include <stddef.h>
 
 #include <deque>
@@ skipping 42 matching lines @@
 
   void Initialize();
 
   void BindFramebuffer();
   void SwapBuffers(const gfx::Rect& damage);
   void PageFlipComplete();
   void Reshape(const gfx::Size& size,
                float scale_factor,
                const gfx::ColorSpace& color_space,
                bool use_stencil);
+  void RecreateBuffers();
+  uint32_t GetCurrentTextureId() const;
 
-  void RecreateBuffers();
-
-  uint32_t current_texture_id() const {
-    return current_surface_ ? current_surface_->texture : 0;
-  }
   uint32_t fbo() const { return fbo_; }
   uint32_t internal_format() const { return internal_format_; }
 
  private:
   friend class BufferQueueTest;
   friend class AllocatedSurface;
 
   struct DISPLAY_COMPOSITOR_EXPORT AllocatedSurface {
     AllocatedSurface(BufferQueue* buffer_queue,
                      std::unique_ptr<gfx::GpuMemoryBuffer> buffer,
@@ skipping 51 matching lines @@
   GLHelper* gl_helper_;
   gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager_;
   gpu::SurfaceHandle surface_handle_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferQueue);
 };
 
 }  // namespace display_compositor
 
 #endif  // COMPONENTS_DISPLAY_COMPOSITOR_BUFFER_QUEUE_H_