cc: Set up the framework to restrict access to Layer internals.

cc/layers/heads_up_display_layer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/heads_up_display_layer.h"
 
 #include <algorithm>
 
 #include "base/trace_event/trace_event.h"
 #include "cc/layers/heads_up_display_layer_impl.h"
@@ skipping 45 matching lines @@
   SetBounds(bounds);
   SetTransform(matrix);
 }
 
 bool HeadsUpDisplayLayer::HasDrawableContent() const {
   return true;
 }
 
 std::unique_ptr<LayerImpl> HeadsUpDisplayLayer::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
-  return HeadsUpDisplayLayerImpl::Create(tree_impl, layer_id_);
+  return HeadsUpDisplayLayerImpl::Create(tree_impl, id());
 }
 
 void HeadsUpDisplayLayer::SetTypeForProtoSerialization(
     proto::LayerNode* proto) const {
   proto->set_type(proto::LayerNode::HEADS_UP_DISPLAY_LAYER);
 }
 
 void HeadsUpDisplayLayer::PushPropertiesTo(LayerImpl* layer) {
   Layer::PushPropertiesTo(layer);
   TRACE_EVENT0("cc", "HeadsUpDisplayLayer::PushPropertiesTo");
   HeadsUpDisplayLayerImpl* layer_impl =
       static_cast<HeadsUpDisplayLayerImpl*>(layer);
 
   layer_impl->SetHUDTypeface(typeface_);
 }
 
 }  // namespace cc