Build property trees for the HUD layer when using layer lists

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 223fc65c0c1b7f3d295d643ee26d871de324e14f..b33473298bdc060917721e83c3daacb6acb0e5e7 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -17,6 +17,7 @@
 #include "base/trace_event/trace_event.h"
 #include "cc/base/simple_enclosed_region.h"
 #include "cc/input/main_thread_scrolling_reason.h"
+#include "cc/layers/heads_up_display_layer.h"
 #include "cc/layers/layer_client.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/scrollbar_layer_interface.h"
@@ -1304,6 +1305,18 @@ void Layer::SetScrollbarsHiddenFromImplSide(bool hidden) {
     inputs_.client->didChangeScrollbarsHidden(hidden);
 }
 
+void Layer::copyPropertyTreeStateTo(HeadsUpDisplayLayer* hud_layer) const {
+  // When not using layer lists the hud layer's properties should be built by
+  // PropertyTreeBuilder.
+  DCHECK(layer_tree_host_->GetSettings().use_layer_lists);
+
+  hud_layer->SetTransformTreeIndex(transform_tree_index_);
+  hud_layer->SetEffectTreeIndex(effect_tree_index_);
+  hud_layer->SetClipTreeIndex(clip_tree_index_);
+  hud_layer->SetScrollTreeIndex(scroll_tree_index_);
+  hud_layer->set_property_tree_sequence_number(property_tree_sequence_number_);
+}
+
 bool Layer::FilterIsAnimating() const {
   return GetMutatorHost()->IsAnimatingFilterProperty(
       element_id(), GetElementTypeForAnimation());