Hollow out more of the tracing system in oilpan

sky/engine/bindings/core/v8/Nullable.h

Index: sky/engine/bindings/core/v8/Nullable.h
diff --git a/sky/engine/bindings/core/v8/Nullable.h b/sky/engine/bindings/core/v8/Nullable.h
index 590c09ad3873a84ddd795586982dc1e10f35792c..2af95d5d2150473bd0d7a2b4c3b69a814a78a264 100644
--- a/sky/engine/bindings/core/v8/Nullable.h
+++ b/sky/engine/bindings/core/v8/Nullable.h
@@ -51,11 +51,6 @@ public:
         return (m_isNull && other.m_isNull) || (!m_isNull && !other.m_isNull && m_value == other.m_value);
     }
 
-    void trace(Visitor* visitor)
-    {
-        TraceIfNeeded<T>::trace(visitor, &m_value);
-    }
-
 private:
     T m_value;
     bool m_isNull;