Oilpan: support eager tracing of objects when marking.

Source/platform/heap/HeapLinkedStack.h

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 92 matching lines @@
     m_head = m_head->m_next;
     --m_size;
 }
 
 template <typename T>
 inline size_t HeapLinkedStack<T>::size()
 {
     return m_size;
 }
 
-}
+template<typename T>
+class TraceEagerlyTrait<HeapLinkedStack<T> > {
+public:
+    static const bool value = IS_EAGERLY_TRACED_HEAP_COLLECTION(T);
+};
+
+} // namespace blink
 
 #endif // HeapLinkedStack_h