cc : Make CallFunctionForSubtree on impl use layer iterator

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 5437ba5e60b62ea69580f3fb7761d241dddac368..f80f921d861b4cf581d4359e4eb21c793deee131 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -358,8 +358,8 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
   if (is_new_trace &&
       frame_viewer_instrumentation::IsTracingLayerTreeSnapshots() &&
       root_layer()) {
-    LayerTreeHostCommon::CallFunctionForSubtree(
-        root_layer(), [](Layer* layer) { layer->DidBeginTracing(); });
+    LayerTreeHostCommon::CallFunctionForEveryLayer(
+        this, [](Layer* layer) { layer->DidBeginTracing(); });
   }
 
   LayerTreeImpl* sync_tree = host_impl->sync_tree();
@@ -1567,10 +1567,9 @@ void LayerTreeHost::FromProtobufForCommit(const proto::LayerTreeHost& proto) {
   // updated for other reasons. All layers that at this point are part of the
   // layer tree are valid, so it is OK that they have a valid sequence number.
   int seq_num = property_trees_.sequence_number;
-  LayerTreeHostCommon::CallFunctionForSubtree(
-      root_layer(), [seq_num](Layer* layer) {
-        layer->set_property_tree_sequence_number(seq_num);
-      });
+  LayerTreeHostCommon::CallFunctionForEveryLayer(this, [seq_num](Layer* layer) {
+    layer->set_property_tree_sequence_number(seq_num);
+  });
 
   surface_id_namespace_ = proto.surface_id_namespace();
   next_surface_sequence_ = proto.next_surface_sequence();