tracing: Make ConvertableToTraceFormat move-only scoped_ptr

cc/scheduler/begin_frame_source_unittest.cc

Index: cc/scheduler/begin_frame_source_unittest.cc
diff --git a/cc/scheduler/begin_frame_source_unittest.cc b/cc/scheduler/begin_frame_source_unittest.cc
index 16640ee5714eb79ae71a5079347ffc69ef58e825..6ab9074448c07b47b029851216a063bb8f955904 100644
--- a/cc/scheduler/begin_frame_source_unittest.cc
+++ b/cc/scheduler/begin_frame_source_unittest.cc
@@ -199,8 +199,8 @@ TEST(BeginFrameSourceBaseTest, DetectAsValueIntoLoop) {
   obs.source_ = &source;
   source.AddObserver(&obs);
 
-  scoped_refptr<base::trace_event::TracedValue> state =
-      new base::trace_event::TracedValue();
+  scoped_ptr<base::trace_event::TracedValue> state(
+      new base::trace_event::TracedValue());
   source.AsValueInto(state.get());
 }