Hit test on the layer tree rather than the RSLL

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index be53d19c951daf4dec6c7232f733efc697a29435..19ef110b918aae6fb85813f2a8e8190e332ef5c4 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -248,6 +248,18 @@ class CC_EXPORT LayerTreeImpl {
     return render_surface_layer_list_id_;
   }
 
+  LayerImpl* FindFirstScrollingLayerThatIsHitByPoint(
+      const gfx::PointF& screen_space_point);
+
+  LayerImpl* FindLayerThatIsHitByPoint(const gfx::PointF& screen_space_point);
+
+  LayerImpl* FindLayerThatIsHitByPointInTouchHandlerRegion(
+      const gfx::PointF& screen_space_point);
+
+  void set_current_render_surface_list_id_for_testing(int id) {
+    render_surface_layer_list_id_ = id;
+  }
+
  protected:
   explicit LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl);