Use an auxiliary list of animation controllers.

cc/layer_tree_host.h

Index: cc/layer_tree_host.h
diff --git a/cc/layer_tree_host.h b/cc/layer_tree_host.h
index 4423082fd3d2780db453dcc52669448dad1f27b4..21af798f4334bb7e76ee7b4f5711d838329fb8f5 100644
--- a/cc/layer_tree_host.h
+++ b/cc/layer_tree_host.h
@@ -14,6 +14,7 @@
 #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/layer_tree_host_client.h"
 #include "cc/layer_tree_host_common.h"
@@ -36,6 +37,15 @@ struct hash<WebKit::WebGraphicsContext3D*> {
   }
 };
 } // namespace BASE_HASH_NAMESPACE
+
+namespace BASE_HASH_NAMESPACE {
+template<>
+struct hash<cc::LayerAnimationController*> {
+  size_t operator()(cc::LayerAnimationController* ptr) const {
+    return hash<size_t>()(reinterpret_cast<size_t>(ptr));
+  }
+};
+} // namespace BASE_HASH_NAMESPACE
 #endif // COMPILER
 
 namespace cc {
@@ -113,7 +123,8 @@ struct CC_EXPORT RendererCapabilities {
     int maxTextureSize;
 };
 
-class CC_EXPORT LayerTreeHost : public RateLimiterClient {
+class CC_EXPORT LayerTreeHost : public RateLimiterClient,
+                                public AnimationRegistrar {
 public:
     static scoped_ptr<LayerTreeHost> create(LayerTreeHostClient*, const LayerTreeSettings&, scoped_ptr<Thread> implThread);
     virtual ~LayerTreeHost();
@@ -190,7 +201,6 @@ public:
     bool commitRequested() const;
 
     void setAnimationEvents(scoped_ptr<AnimationEventsVector>, base::Time wallClockTime);
-    virtual void didAddAnimation();
 
     Layer* rootLayer() { return m_rootLayer.get(); }
     const Layer* rootLayer() const { return m_rootLayer.get(); }
@@ -248,8 +258,15 @@ protected:
     bool initialize(scoped_ptr<Thread> implThread);
     bool initializeForTesting(scoped_ptr<Proxy> proxyForTesting);
 
+    // AnimationRegistar implementation.
+    virtual void DidActivateAnimationController(LayerAnimationController*) OVERRIDE;
+    virtual void DidDeactivateAnimationController(LayerAnimationController*) OVERRIDE;
+    virtual void RegisterAnimationController(LayerAnimationController*) OVERRIDE;
+    virtual void UnregisterAnimationController(LayerAnimationController*) OVERRIDE;
+
 private:
     typedef std::vector<scoped_refptr<Layer> > LayerList;
+    typedef base::hash_set<LayerAnimationController*> AnimationControllerSet;
 
     bool initializeProxy(scoped_ptr<Proxy> proxy);
     void initializeRenderer();
@@ -271,7 +288,6 @@ private:
     void setAnimationEventsRecursive(const AnimationEventsVector&, Layer*, base::Time wallClockTime);
 
     bool m_animating;
-    bool m_needsAnimateLayers;
     bool m_needsFullTreeSync;
 
     base::CancelableClosure m_prepaintCallback;
@@ -318,6 +334,12 @@ private:
 
     static bool s_needsFilterContext;
 
+    AnimationControllerSet m_activeAnimationControllers;
+
+#if !defined(NDEBUG)
+    AnimationControllerSet m_allAnimationControllers;
+#endif
+
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };