Activate LayerImpl tree with sync+push instead of pointer swap

cc/heads_up_display_layer_impl.cc

Index: cc/heads_up_display_layer_impl.cc
diff --git a/cc/heads_up_display_layer_impl.cc b/cc/heads_up_display_layer_impl.cc
index eb1fb615d0c13cb0639249ff93fa50faa382b0bf..e581a57ed794130c3e9c4a1c53718891f3b8afc5 100644
--- a/cc/heads_up_display_layer_impl.cc
+++ b/cc/heads_up_display_layer_impl.cc
@@ -75,6 +75,22 @@ HeadsUpDisplayLayerImpl::~HeadsUpDisplayLayerImpl()
 {
 }
 
+scoped_ptr<LayerImpl> HeadsUpDisplayLayerImpl::createLayerImpl(LayerTreeImpl* treeImpl)
+{
+    return HeadsUpDisplayLayerImpl::create(treeImpl, id()).PassAs<LayerImpl>();
+}
+
+void HeadsUpDisplayLayerImpl::pushPropertiesTo(LayerImpl* layerImpl)
+{
+    LayerImpl::pushPropertiesTo(layerImpl);
+
+    if (!m_fontAtlas)
+        return;
+
+    HeadsUpDisplayLayerImpl* hudLayerImpl = static_cast<HeadsUpDisplayLayerImpl*>(layerImpl);
+    hudLayerImpl->setFontAtlas(m_fontAtlas.Pass());
+}
+
 void HeadsUpDisplayLayerImpl::setFontAtlas(scoped_ptr<FontAtlas> fontAtlas)
 {
     m_fontAtlas = fontAtlas.Pass();