cc: Make all layer recursion use CallFunctionForSubtree

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 3a33441d5d3d14db21e5832d0d5beb1170bd79e1..f006032480d8e942366732d34f3344cf686cc423 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -350,15 +350,13 @@ void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
   pending_tree->SetCurrentlyScrollingLayer(pending_scrolling_layer_twin);
 }
 
-static void DidBecomeActiveRecursive(LayerImpl* layer) {
+static void MarkActive(LayerImpl* layer) {
   layer->DidBecomeActive();
-  for (size_t i = 0; i < layer->children().size(); ++i)
-    DidBecomeActiveRecursive(layer->children()[i]);
 }
 
 void LayerTreeImpl::DidBecomeActive() {
   if (root_layer())
-    DidBecomeActiveRecursive(root_layer());
+    LayerTreeHostCommon::CallFunctionForSubtree(MarkActive, root_layer());
   FindRootScrollLayer();
   UpdateMaxScrollOffset();
 }