Reduce SurfaceIdAllocator usage and tie SurfaceFactory to a single FrameSinkId

services/ui/surfaces/display_compositor.h

 // Copyright 2016 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 SERVICES_UI_SURFACES_DISPLAY_COMPOSITOR_H_
 #define SERVICES_UI_SURFACES_DISPLAY_COMPOSITOR_H_
 
 #include "cc/surfaces/display_client.h"
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_factory.h"
@@ skipping 50 matching lines @@
   // SurfaceFactoryClient implementation.
   void ReturnResources(const cc::ReturnedResourceArray& resources) override;
   void SetBeginFrameSource(cc::BeginFrameSource* begin_frame_source) override;
 
   // DisplayClient implementation.
   void DisplayOutputSurfaceLost() override;
   void DisplayWillDrawAndSwap(bool will_draw_and_swap,
                               const cc::RenderPassList& render_passes) override;
   void DisplayDidDrawAndSwap() override;
 
+  cc::FrameSinkId frame_sink_id_;

[sky, 2016/10/03 19:18:25]

If possible make this const.

[Fady Samuel, 2016/10/03 19:45:29]

Done.

   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<SurfacesState> surfaces_state_;
+  cc::SurfaceIdAllocator allocator_;
   cc::SurfaceFactory factory_;
-  cc::SurfaceIdAllocator allocator_;
   cc::SurfaceId surface_id_;
 
   gfx::Size display_size_;
   std::unique_ptr<cc::Display> display_;
   DISALLOW_COPY_AND_ASSIGN(DisplayCompositor);
 };
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_SURFACES_DISPLAY_COMPOSITOR_H_