Activate LayerImpl tree with sync+push instead of pointer swap

cc/delegated_renderer_layer_impl.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/delegated_renderer_layer_impl.h"
 
 #include "cc/append_quads_data.h"
 #include "cc/math_util.h"
 #include "cc/quad_sink.h"
 #include "cc/render_pass_draw_quad.h"
@@ skipping 42 matching lines @@
   if (!render_passes_in_draw_order_.empty())
     render_passes_in_draw_order_.back()->damage_rect.Union(old_root_damage);
 }
 
 void DelegatedRendererLayerImpl::ClearRenderPasses() {
   // FIXME: Release the resources back to the nested compositor.
   render_passes_index_by_id_.clear();
   render_passes_in_draw_order_.clear();
 }
 
+scoped_ptr<LayerImpl> DelegatedRendererLayerImpl::createLayerImpl(LayerTreeImpl* treeImpl)
+{
+    return DelegatedRendererLayerImpl::create(treeImpl, id()).PassAs<LayerImpl>();
+}
+
 void DelegatedRendererLayerImpl::didLoseOutputSurface() {
   ClearRenderPasses();
 }
 
 static inline int IndexToId(int index) { return index + 1; }
 static inline int IdToIndex(int id) { return id - 1; }
 
 RenderPass::Id DelegatedRendererLayerImpl::firstContributingRenderPassId()
     const {
   return RenderPass::Id(id(), IndexToId(0));
@@ skipping 144 matching lines @@
 
     quad_sink->append(output_quad.Pass(), *append_quads_data);
   }
 }
 
 const char* DelegatedRendererLayerImpl::layerTypeAsString() const {
   return "DelegatedRendererLayer";
 }
 
 }  // namespace cc