Make sure all the touch events during an active fling are uncancelable

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index b69457cfba55c6badf2695703688e1557c434eba..76ef153aa0a6a65adfb66a86158604c354f2ae05 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -707,6 +707,8 @@ class CC_EXPORT LayerTreeHostImpl
   void ImageDecodeFinished(const base::Callback<void(bool)>& embedder_callback,
                            bool decode_succeeded);
 
+  bool IsScrolledBy(LayerImpl* child, ScrollNode* ancestor);
+
   using UIResourceMap = std::unordered_map<UIResourceId, UIResourceData>;
   UIResourceMap ui_resource_map_;