Ref count layer animation controllers.

cc/layer_tree_host_impl.h

Index: cc/layer_tree_host_impl.h
diff --git a/cc/layer_tree_host_impl.h b/cc/layer_tree_host_impl.h
index c7e9c0b4c3ab90fec3f66678311091d26fb96285..d56a5504fd673b14188135bff27d98643c64bad9 100644
--- a/cc/layer_tree_host_impl.h
+++ b/cc/layer_tree_host_impl.h
@@ -9,6 +9,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "cc/animation_events.h"
+#include "cc/animation_registrar.h"
 #include "cc/cc_export.h"
 #include "cc/input_handler.h"
 #include "cc/output_surface_client.h"
@@ -248,9 +249,7 @@ public:
 
     bool hasTransparentBackground() const { return m_hasTransparentBackground; }
     void setHasTransparentBackground(bool transparent) { m_hasTransparentBackground = transparent; }
-
-    bool needsAnimateLayers() const { return m_needsAnimateLayers; }
-    void setNeedsAnimateLayers() { m_needsAnimateLayers = true; }
+    bool needsAnimateLayers() const { return !m_animationRegistrar->active_animation_controllers().empty(); }
 
     bool needsUpdateDrawProperties() const { return m_needsUpdateDrawProperties; }
     void setNeedsUpdateDrawProperties() { m_needsUpdateDrawProperties = true; }
@@ -270,6 +269,8 @@ public:
 
     Proxy* proxy() const { return m_proxy; }
 
+    AnimationRegistrar* animationRegistrar() const { return m_animationRegistrar.get(); }
+
     void setDebugState(const LayerTreeDebugState& debugState) { m_debugState = debugState; }
     const LayerTreeDebugState& debugState() const { return m_debugState; }
 
@@ -314,6 +315,8 @@ protected:
     // Virtual for testing.
     virtual base::TimeDelta lowFrequencyAnimationInterval() const;
 
+    const AnimationRegistrar::AnimationControllerMap& activeAnimationControllers() const { return m_animationRegistrar->active_animation_controllers(); }
+
     LayerTreeHostImplClient* m_client;
     Proxy* m_proxy;
 
@@ -369,8 +372,6 @@ private:
     SkColor m_backgroundColor;
     bool m_hasTransparentBackground;
 
-    // If this is true, it is necessary to traverse the layer tree ticking the animators.
-    bool m_needsAnimateLayers;
     bool m_needsUpdateDrawProperties;
     bool m_pinchGestureActive;
     gfx::Point m_previousPinchAnchor;
@@ -400,6 +401,8 @@ private:
     size_t m_lastSentMemoryVisibleAndNearbyBytes;
     size_t m_lastSentMemoryUseBytes;
 
+    scoped_ptr<AnimationRegistrar> m_animationRegistrar;
+
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };