Moves ownership of the cc::Display's BeginFrameSource out of Display.

android_webview/browser/surfaces_instance.h

Index: android_webview/browser/surfaces_instance.h
diff --git a/android_webview/browser/surfaces_instance.h b/android_webview/browser/surfaces_instance.h
index 8fb59b27cd8fab687ef7ea747e0b7f9c1aeb6b9d..9ed6557dc63a32c0a1a954a3e12ba02ad0f025d6 100644
--- a/android_webview/browser/surfaces_instance.h
+++ b/android_webview/browser/surfaces_instance.h
@@ -73,6 +73,7 @@ class SurfacesInstance : public base::RefCounted<SurfacesInstance>,
   cc::FrameSinkId frame_sink_id_;
 
   std::unique_ptr<cc::SurfaceManager> surface_manager_;
+  std::unique_ptr<cc::BeginFrameSource> begin_frame_source_;
   std::unique_ptr<cc::Display> display_;
   std::unique_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
   std::unique_ptr<cc::SurfaceFactory> surface_factory_;