Implement GpuArcVideoService for arc video accelerator

components/arc/arc_bridge_service_impl.h

Index: components/arc/arc_bridge_service_impl.h
diff --git a/components/arc/arc_bridge_service_impl.h b/components/arc/arc_bridge_service_impl.h
index 969e0cb7792c4966c08de65dbcf39709878b1974..df4b5b603e5ed930a2309003bbd5e5da0fd9fd02 100644
--- a/components/arc/arc_bridge_service_impl.h
+++ b/components/arc/arc_bridge_service_impl.h
@@ -63,6 +63,11 @@ class ArcBridgeServiceImpl : public ArcBridgeService,
   // Requests ARC process list.
   bool RequestProcessList() override;
 
+  // ArcBridgeHost:
+  void OnVideoInstanceReady(VideoInstancePtr video_ptr) override;
+
+  VideoInstance* video_instance() override { return video_ptr_.get(); }
+
  private:
   friend class ArcBridgeTest;
   FRIEND_TEST_ALL_PREFIXES(ArcBridgeTest, Basic);
@@ -113,6 +118,7 @@ class ArcBridgeServiceImpl : public ArcBridgeService,
   // Mojo endpoints.
   mojo::Binding<ArcBridgeHost> binding_;
   ArcBridgeInstancePtr instance_ptr_;
+  VideoInstancePtr video_ptr_;
 
   // If the user's session has started.
   bool session_started_;