Use element id's for animations

ui/compositor/layer.cc

Index: ui/compositor/layer.cc
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index e23e87fb63b223517a354fa7034eaab5a434ba61..15daf2dd0e46aed5e8eb57b7f4e7c033b276cc38 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -512,6 +512,7 @@ void Layer::SwitchToLayer(scoped_refptr<cc::Layer> new_layer) {
   cc_layer_->SetContentsOpaque(fills_bounds_opaquely_);
   cc_layer_->SetIsDrawable(type_ != LAYER_NOT_DRAWN);
   cc_layer_->SetHideLayerAndSubtree(!visible_);
+  cc_layer_->SetElementId(cc::ElementId(cc_layer_->id()));
 
   SetLayerFilters();
   SetLayerBackgroundFilters();
@@ -988,6 +989,7 @@ void Layer::CreateCcLayer() {
   cc_layer_->SetContentsOpaque(true);
   cc_layer_->SetIsDrawable(type_ != LAYER_NOT_DRAWN);
   cc_layer_->SetLayerClient(this);
+  cc_layer_->SetElementId(cc::ElementId(cc_layer_->id()));
   RecomputePosition();
 }