Add Mojo API for Blink hit testing

content/browser/frame_host/render_widget_host_view_child_frame.h

Index: content/browser/frame_host/render_widget_host_view_child_frame.h
diff --git a/content/browser/frame_host/render_widget_host_view_child_frame.h b/content/browser/frame_host/render_widget_host_view_child_frame.h
index f4f5b422186d431c70135c294b27fab8bc059e86..c0ed9cf50f4b4d1f95cd95b9c87ef643b1fc2875 100644
--- a/content/browser/frame_host/render_widget_host_view_child_frame.h
+++ b/content/browser/frame_host/render_widget_host_view_child_frame.h
@@ -115,8 +115,8 @@ class CONTENT_EXPORT RenderWidgetHostViewChildFrame
   void GestureEventAck(const blink::WebGestureEvent& event,
                        InputEventAckState ack_result) override;
   void DidCreateNewRendererCompositorFrameSink(
-      viz::mojom::CompositorFrameSinkClient* renderer_compositor_frame_sink)
-      override;
+      viz::mojom::CompositorFrameSinkClient* renderer_compositor_frame_sink,
+      viz::mojom::FrameInputHitTest*) override;
   void SubmitCompositorFrame(const viz::LocalSurfaceId& local_surface_id,
                              cc::CompositorFrame frame) override;
   void OnDidNotProduceFrame(const viz::BeginFrameAck& ack) override;
@@ -267,7 +267,8 @@ class CONTENT_EXPORT RenderWidgetHostViewChildFrame
                                 const ReadbackRequestCallback& callback,
                                 const SkColorType preferred_color_type);
 
-  void CreateCompositorFrameSinkSupport();
+  void CreateCompositorFrameSinkSupport(
+      viz::mojom::FrameInputHitTest* = nullptr);
   void ResetCompositorFrameSinkSupport();
   void DetachFromTouchSelectionClientManagerIfNecessary();