Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/animation/animation_host_perftest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/animation/animation_host.h"
 
 #include "base/threading/thread_task_runner_handle.h"
 #include "cc/animation/animation_id_provider.h"
 #include "cc/animation/animation_player.h"
 #include "cc/animation/animation_timeline.h"
@@ skipping 26 matching lines @@
   }
 
   void TearDown() override {
     root_layer_ = nullptr;
     root_layer_impl_ = nullptr;
 
     layer_tree_host_->SetRootLayer(nullptr);
     layer_tree_host_ = nullptr;
   }
 
-  AnimationHost* host() const { return layer_tree_host_->animation_host(); }
+  AnimationHost* host() const {
+    return layer_tree_host_->GetLayerTree()->animation_host();
+  }
   AnimationHost* host_impl() const {
     return layer_tree_host_->host_impl()->animation_host();
   }
 
   void CreatePlayers(const int num_players) {
     scoped_refptr<AnimationTimeline> timeline =
         AnimationTimeline::Create(AnimationIdProvider::NextTimelineId());
     host()->AddAnimationTimeline(timeline);
 
     const int first_player_id = AnimationIdProvider::NextPlayerId();
@@ skipping 74 matching lines @@
   CreateTimelines(10);
   DoTest();
 }
 
 TEST_F(AnimationHostPerfTest, Push1000TimelinesPropertiesTo) {
   CreateTimelines(1000);
   DoTest();
 }
 
 }  // namespace cc