Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/debug/micro_benchmark.cc

 // Copyright 2013 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/debug/micro_benchmark.h"
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/logging.h"
@@ skipping 10 matching lines @@
       processed_for_benchmark_impl_(false),
       id_(0) {
 }
 
 MicroBenchmark::~MicroBenchmark() {}
 
 bool MicroBenchmark::IsDone() const {
   return is_done_;
 }
 
-void MicroBenchmark::DidUpdateLayers(LayerTreeHost* host) {}
+void MicroBenchmark::DidUpdateLayers(LayerTree* layer_tree) {}
 
 void MicroBenchmark::NotifyDone(std::unique_ptr<base::Value> result) {
   callback_.Run(std::move(result));
   is_done_ = true;
 }
 
 void MicroBenchmark::RunOnLayer(Layer* layer) {}
 
 void MicroBenchmark::RunOnLayer(PictureLayer* layer) {}
 
@@ skipping 11 matching lines @@
   processed_for_benchmark_impl_ = true;
   return CreateBenchmarkImpl(origin_task_runner);
 }
 
 std::unique_ptr<MicroBenchmarkImpl> MicroBenchmark::CreateBenchmarkImpl(
     scoped_refptr<base::SingleThreadTaskRunner> origin_task_runner) {
   return base::WrapUnique<MicroBenchmarkImpl>(nullptr);
 }
 
 }  // namespace cc