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 4e4013236a84294ac053b5b9f16dae1e296c4c55..a2b1c14c86a639e513cee5cb47fe1c56c5f14db4 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);