Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/trees/layer_tree_host_common.h

Index: cc/trees/layer_tree_host_common.h
diff --git a/cc/trees/layer_tree_host_common.h b/cc/trees/layer_tree_host_common.h
index 6867e942f368c033ac998957dad3de579c7f0453..6419bf337f5e81f9aaa80a3b342824ce747af7c0 100644
--- a/cc/trees/layer_tree_host_common.h
+++ b/cc/trees/layer_tree_host_common.h
@@ -132,7 +132,7 @@ class CC_EXPORT LayerTreeHostCommon {
       CalcDrawPropsImplInputsForTesting* inputs);
 
   template <typename Function>
-  static void CallFunctionForEveryLayer(LayerTreeHost* layer,
+  static void CallFunctionForEveryLayer(LayerTree* layer,
                                         const Function& function);
 
   template <typename Function>
@@ -179,7 +179,7 @@ struct CC_EXPORT ScrollAndScaleSet {
 };
 
 template <typename Function>
-void LayerTreeHostCommon::CallFunctionForEveryLayer(LayerTreeHost* host,
+void LayerTreeHostCommon::CallFunctionForEveryLayer(LayerTree* host,
                                                     const Function& function) {
   for (auto* layer : *host) {
     function(layer);