Move compositor InputHandler from RenderViewImpl to RenderWidget.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index e87b0daab8714ee640271fab39c6937d412ec932..915f7ea72f25aaea11529420ca982b2b29ed0de3 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -3002,6 +3002,7 @@ void LayerTreeHostImpl::ApplyScroll(ScrollNode* scroll_node,
   // we want to scroll the inner viewport -- to allow panning while zoomed --
   // but also move browser controls if needed.
   bool is_inner_viewport_scroll_layer =
+      InnerViewportScrollLayer() &&
       scroll_node->owning_layer_id == InnerViewportScrollLayer()->id();
 
   if (is_viewport_scroll_layer || is_inner_viewport_scroll_layer) {