Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/debug/micro_benchmark_controller.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_controller.h"
 
 #include <limits>
 #include <string>
 
 #include "base/callback.h"
@@ skipping 87 matching lines @@
     }
 
     if (benchmark_impl.get())
       host_impl->ScheduleMicroBenchmark(std::move(benchmark_impl));
   }
 }
 
 void MicroBenchmarkController::DidUpdateLayers() {
   for (const auto& benchmark : benchmarks_) {
     if (!benchmark->IsDone())
-      benchmark->DidUpdateLayers(host_);
+      benchmark->DidUpdateLayers(host_->GetLayerTree());
   }
 
   CleanUpFinishedBenchmarks();
 }
 
 void MicroBenchmarkController::CleanUpFinishedBenchmarks() {
   benchmarks_.erase(
       std::remove_if(benchmarks_.begin(), benchmarks_.end(),
                      [](const std::unique_ptr<MicroBenchmark>& benchmark) {
                        return benchmark->IsDone();
                      }),
       benchmarks_.end());
 }
 
 }  // namespace cc