Enable accelerated animations for orphaned layers

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index 85bd2f7e5ad5c1612df2acc6e87cc608454000ba..26c447493b9431e12e5269ba4e20b1fee93150c9 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -335,6 +335,12 @@ void RenderWidgetCompositor::didStopFlinging() {
   layer_tree_host_->didStopFlinging();
 }
 
+void RenderWidgetCompositor::registerForAnimations(WebKit::WebLayer* layer) {
+  cc::Layer* cc_layer = static_cast<WebKit::WebLayerImpl*>(layer)->layer();
+  cc_layer->layerAnimationController()->setAnimationRegistrar(
+      layer_tree_host_->animationRegistrar());
+}
+
 bool RenderWidgetCompositor::compositeAndReadback(void *pixels,
                                                   const WebRect& rect) {
   return layer_tree_host_->compositeAndReadback(pixels, rect);