tracing: Make ConvertableToTraceFormat move-only scoped_ptr

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 8b1227270b5f39e3cfefa936052e0f585d6c55e0..3263e3cbdbd570c5f9c484f0c7536ebb9db69ac7 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -3543,12 +3543,11 @@ base::TimeDelta LayerTreeHostImpl::CurrentBeginFrameInterval() const {
   return current_begin_frame_tracker_.Interval();
 }
 
-scoped_refptr<base::trace_event::ConvertableToTraceFormat>
+scoped_ptr<base::trace_event::ConvertableToTraceFormat>
 LayerTreeHostImpl::AsValueWithFrame(FrameData* frame) const {
-  scoped_refptr<base::trace_event::TracedValue> state =
-      new base::trace_event::TracedValue();
+  auto state = make_scoped_ptr(new base::trace_event::TracedValue);
   AsValueWithFrameInto(frame, state.get());
-  return state;
+  return std::move(state);
 }
 
 void LayerTreeHostImpl::AsValueWithFrameInto(