cc: Make LayerTreeImpl dump layer list to FrameViewer and Devtools

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 9b7f53277d3db9a06d03a8b6680943f3260e2049..de1664ad8c7b2788549aa16f1425652957d06951 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -1246,13 +1246,6 @@ void LayerImpl::AsValueInto(base::trace_event::TracedValue* state) const {
     non_fast_scrollable_region_.AsValueInto(state);
     state->EndArray();
   }
-  state->BeginArray("children");
-  for (size_t i = 0; i < children_.size(); ++i) {
-    state->BeginDictionary();
-    children_[i]->AsValueInto(state);
-    state->EndDictionary();
-  }
-  state->EndArray();
   if (mask_layer_) {
     state->BeginDictionary("mask_layer");
     mask_layer_->AsValueInto(state);