Update from chromium https://crrev.com/304586

cc/layers/scrollbar_layer_impl_base.cc

Index: cc/layers/scrollbar_layer_impl_base.cc
diff --git a/cc/layers/scrollbar_layer_impl_base.cc b/cc/layers/scrollbar_layer_impl_base.cc
index 4248617f5bcc75eab4c20d632871f839b2202770..beac79f6cca24c68dc17253f1193a6918f5998a2 100644
--- a/cc/layers/scrollbar_layer_impl_base.cc
+++ b/cc/layers/scrollbar_layer_impl_base.cc
@@ -69,11 +69,7 @@ void RegisterScrollbarWithLayers(ScrollbarLayerImplBase* scrollbar,
   for (LayerImpl* current_layer = scroll_layer;
        current_layer && current_layer != container_layer->parent();
        current_layer = current_layer->parent()) {
-    // TODO(wjmaclean) We shouldn't need to exempt the scroll_layer from the
-    // scrollable() test below. https://crbug.com/367858.
-    if (current_layer->scrollable() || current_layer == container_layer ||
-        current_layer == scroll_layer)
-      (current_layer->*operation)(scrollbar);
+    (current_layer->*operation)(scrollbar);
   }
 }
 }  // namespace