[Oilpan] Add use-after-free detector in Member<>

third_party/WebKit/Source/platform/heap/Visitor.h

 /*
  * Copyright (C) 2013 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 121 matching lines @@
         static_assert(IsGarbageCollectedType<T>::value, "T needs to be a garbage collected object");
         if (!t)
             return;
         TraceTrait<T>::mark(Derived::fromHelper(this), t);
     }
 
     // Member version of the one-argument templated trace method.
     template<typename T>
     void trace(const Member<T>& t)
     {
-        mark(t.get());
+        mark(t.unsafeGet());
     }
 
     // Fallback method used only when we need to trace raw pointers of T.
     // This is the case when a member is a union where we do not support members.
     template<typename T>
     void trace(const T* t)
     {
         mark(const_cast<T*>(t));
     }
     template<typename T>
@@ skipping 236 matching lines @@
     static const String get()
     {
         return WTF::extractTypeNameFromFunctionName(WTF::extractNameFunction<T>());
     }
 };
 #endif
 
 } // namespace blink
 
 #endif // Visitor_h