Enable accelerated animations for orphaned layers

cc/layer_tree_host.cc

Index: cc/layer_tree_host.cc
diff --git a/cc/layer_tree_host.cc b/cc/layer_tree_host.cc
index 44833e72ec30c0458846626996c9dc5d533ce00a..6062aae6c520c63a40aa608c062aa6babe17a1e4 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -89,8 +89,9 @@ LayerTreeHost::LayerTreeHost(LayerTreeHostClient* client, const LayerTreeSetting
     , m_backgroundColor(SK_ColorWHITE)
     , m_hasTransparentBackground(false)
     , m_partialTextureUpdateRequests(0)
-    , m_animationRegistrar(AnimationRegistrar::create())
 {
+    if (m_settings.acceleratedAnimationEnabled)
+        m_animationRegistrar = AnimationRegistrar::create();
     numLayerTreeInstances++;
 }
 
@@ -867,9 +868,16 @@ void LayerTreeHost::animateLayers(base::TimeTicks monotonicTime, base::Time wall
 
     double monotonicTimeInSeconds = (monotonicTime - base::TimeTicks()).InSecondsF();
 
+    scoped_ptr<AnimationEventsVector> events(make_scoped_ptr(new AnimationEventsVector));
     AnimationRegistrar::AnimationControllerMap copy = m_animationRegistrar->active_animation_controllers();
     for (AnimationRegistrar::AnimationControllerMap::iterator iter = copy.begin(); iter != copy.end(); ++iter)
-        (*iter).second->animate(monotonicTimeInSeconds, 0);
+        if ((*iter).second->hasNonOrphanedObserver())
+            (*iter).second->animate(monotonicTimeInSeconds, 0);
+        else
+            (*iter).second->animate(monotonicTimeInSeconds, events.get());
+
+    if (!events->empty())
+        setAnimationEvents(events.Pass(), wallClockTime);
 }
 
 void LayerTreeHost::setAnimationEventsRecursive(const AnimationEventsVector& events, Layer* layer, base::Time wallClockTime)