CC Animation: Make AnimationRegistrar a private member of AnimationHost.

cc/test/layer_tree_test.cc

Index: cc/test/layer_tree_test.cc
diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index 82a9a04a9ac259a477db9f20bdbf538f5039be68..a8559e399f2a6e0faccd1f4c4daea8ab55db0731 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -11,7 +11,6 @@
 #include "base/thread_task_runner_handle.h"
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_host.h"
-#include "cc/animation/animation_registrar.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/animation/timing_function.h"
 #include "cc/base/switches.h"
@@ -311,9 +310,8 @@ class LayerTreeHostImplForTesting : public LayerTreeHostImpl {
   void UpdateAnimationState(bool start_ready_animations) override {
     LayerTreeHostImpl::UpdateAnimationState(start_ready_animations);
     bool has_unfinished_animation = false;
-    AnimationRegistrar* registrar = animation_host()->animation_registrar();
     for (const auto& it :
-         registrar->active_animation_controllers_for_testing()) {
+         animation_host()->active_animation_controllers_for_testing()) {
       if (it.second->HasActiveAnimation()) {
         has_unfinished_animation = true;
         break;