Reduce SurfaceIdAllocator usage and tie SurfaceFactory to a single FrameSinkId

android_webview/browser/surfaces_instance.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 ANDROID_WEBVIEW_BROWSER_SURFACES_INSTANCE_H_
 #define ANDROID_WEBVIEW_BROWSER_SURFACES_INSTANCE_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "cc/surfaces/display_client.h"
+#include "cc/surfaces/frame_sink_id.h"
 #include "cc/surfaces/surface_factory_client.h"
 #include "cc/surfaces/surface_id.h"
 
 namespace cc {
 class Display;
 class SurfaceIdAllocator;
 class SurfaceFactory;
 class SurfaceManager;
 }
 
@@ skipping 39 matching lines @@
       bool will_draw_and_swap,
       const cc::RenderPassList& render_passes) override {}
   void DisplayDidDrawAndSwap() override {}
 
   // cc::SurfaceFactoryClient implementation.
   void ReturnResources(const cc::ReturnedResourceArray& resources) override;
   void SetBeginFrameSource(cc::BeginFrameSource* begin_frame_source) override;
 
   void SetEmptyRootFrame();
 
-  uint32_t next_frame_sink_id_;
+  uint32_t next_client_id_;
+
+  cc::FrameSinkId frame_sink_id_;
 
   std::unique_ptr<cc::SurfaceManager> surface_manager_;
   std::unique_ptr<cc::Display> display_;
   std::unique_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
   std::unique_ptr<cc::SurfaceFactory> surface_factory_;
 
   cc::SurfaceId root_id_;
   std::vector<cc::SurfaceId> child_ids_;
 
   // This is owned by |display_|.
   ParentOutputSurface* output_surface_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfacesInstance);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_SURFACES_INSTANCE_H_