Fix assumptions made in LAC::MarkAnimationsForDeletion

cc/animation/animation.h

Index: cc/animation/animation.h
diff --git a/cc/animation/animation.h b/cc/animation/animation.h
index 2677fdeff58e8930aad793bde0ee6b5ad2622550..153e4ef77527f6517cf5c15104ccdcf38a04c89c 100644
--- a/cc/animation/animation.h
+++ b/cc/animation/animation.h
@@ -151,6 +151,9 @@ class CC_EXPORT Animation {
 
   scoped_ptr<Animation> CloneAndInitialize(RunState initial_run_state) const;
 
+  void set_is_controlling_instance_for_test(bool is_controlling_instance) {
+    is_controlling_instance_ = is_controlling_instance;
+  }
   bool is_controlling_instance() const { return is_controlling_instance_; }
 
   void PushPropertiesTo(Animation* other) const;