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 8ad4c011597ac57e884a3f883e8d4b2f553c638b..381f41c03c313ac7aa59c6a4dfd02a3ccf38bbb0 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -1228,13 +1228,6 @@ 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);