Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/debug/rasterize_and_record_benchmark.cc

Index: cc/debug/rasterize_and_record_benchmark.cc
diff --git a/cc/debug/rasterize_and_record_benchmark.cc b/cc/debug/rasterize_and_record_benchmark.cc
index 5babc0edca6a11a1450da3e780d0721ec0a06e88..69bd78035dcabb66ad53dc4ddf0a3ac6efd44cfb 100644
--- a/cc/debug/rasterize_and_record_benchmark.cc
+++ b/cc/debug/rasterize_and_record_benchmark.cc
@@ -72,7 +72,8 @@ RasterizeAndRecordBenchmark::~RasterizeAndRecordBenchmark() {
 void RasterizeAndRecordBenchmark::DidUpdateLayers(LayerTreeHost* host) {
   host_ = host;
   LayerTreeHostCommon::CallFunctionForEveryLayer(
-      host, [this](Layer* layer) { layer->RunMicroBenchmark(this); });
+      host->GetLayerTree(),
+      [this](Layer* layer) { layer->RunMicroBenchmark(this); });
 
   DCHECK(!results_.get());
   results_ = base::WrapUnique(new base::DictionaryValue);