Enable accelerated animations for orphaned layers

cc/layer_animation_controller.cc

Index: cc/layer_animation_controller.cc
diff --git a/cc/layer_animation_controller.cc b/cc/layer_animation_controller.cc
index d5ed278bc57932638f4de36a9a67dc26f2399e3f..76bef283e3c2c830fc02f55839446ee5de66cfe4 100644
--- a/cc/layer_animation_controller.cc
+++ b/cc/layer_animation_controller.cc
@@ -231,6 +231,19 @@ void LayerAnimationController::removeObserver(LayerAnimationValueObserver* obser
     m_observers.RemoveObserver(observer);
 }
 
+bool LayerAnimationController::hasNonOrphanedObserver()
+{
+    if (m_observers.might_have_observers()) {
+        ObserverListBase<LayerAnimationValueObserver>::Iterator it(m_observers);
+        LayerAnimationValueObserver* obs;
+        while ((obs = it.GetNext()) != NULL) {
+            if (!obs->IsOrphaned())
+                return true;
+        }
+    }
+    return false;
+}
+
 void LayerAnimationController::pushNewAnimationsToImplThread(LayerAnimationController* controllerImpl) const
 {
     // Any new animations owned by the main thread's controller are cloned and adde to the impl thread's controller.