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 dabbedd73eee8b0fd00f885268d448f95fb36341..d845d6868cef43dc12e274624d36d1208c64b010 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(), 0));
 
   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(), 0));
   RecomputePosition();
 }