cc: Fix hit-testing in zero-opacity layers.

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 4604043663920750438b5de260b0d8a0249d36b2..512f5c4718b735e75003c17ede2d017b2aa5bde2 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -342,8 +342,8 @@ void LayerTreeImpl::UpdateDrawProperties() {
     UpdateRootScrollLayerSizeDelta();
 
   if (IsActiveTree() &&
-      RootContainerLayer()
-      && !RootContainerLayer()->masks_to_bounds()) {
+      RootContainerLayer() &&
+      !RootContainerLayer()->masks_to_bounds()) {
     UpdateSolidColorScrollbars();
   }
 
@@ -405,6 +405,8 @@ void LayerTreeImpl::UpdateDrawProperties() {
       if (!it.represents_itself())
         continue;
       LayerImpl* layer = *it;
+      if (layer->draw_properties().skip_drawing)
+        continue;
 
       layer->UpdateTilePriorities();
       if (layer->mask_layer())