We don't want to tick animation controllers for non-active 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 c72df0454a79eb3736fc46bd54bd0deffbed9f4a..f4e0d48a6aacf3c555111020ec0303107431fba1 100644
--- a/cc/layer_animation_controller.cc
+++ b/cc/layer_animation_controller.cc
@@ -103,6 +103,9 @@ void LayerAnimationController::pushAnimationUpdatesTo(LayerAnimationController*
 
 void LayerAnimationController::animate(double monotonicTime, AnimationEventsVector* events)
 {
+    if (!hasActiveObserver())
+        return;
+
     startAnimationsWaitingForNextTick(monotonicTime, events);
     startAnimationsWaitingForStartTime(monotonicTime, events);
     startAnimationsWaitingForTargetAvailability(monotonicTime, events);
@@ -457,4 +460,16 @@ void LayerAnimationController::notifyObserversTransformAnimated(const gfx::Trans
                       OnTransformAnimated(transform));
 }
 
+bool LayerAnimationController::hasActiveObserver()
+{
+    if (m_observers.might_have_observers()) {
+        ObserverListBase<LayerAnimationValueObserver>::Iterator it(m_observers);
+        LayerAnimationValueObserver* obs;
+        while ((obs = it.GetNext()) != NULL)
+            if (obs->IsActive())
+                return true;
+    }
+    return false;
+}
+
 }  // namespace cc