Oilpan: remove unused typed pointer cast operation over (Weak)Member.

Source/platform/heap/Handle.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 333 matching lines @@
         return *this;
     }
 
     void clear() { m_raw = nullptr; }
 
     virtual ~Persistent()
     {
         m_raw = nullptr;
     }
 
-    template<typename U>
-    U* as() const
-    {
-        return static_cast<U*>(m_raw);
-    }
-
     void trace(Visitor* visitor)
     {
         STATIC_ASSERT_IS_GARBAGE_COLLECTED(T, "non-garbage collected object should not be in Persistent");
 #if ENABLE(GC_PROFILE_MARKING)
         visitor->setHostInfo(this, m_tracingName.isEmpty() ? "Persistent" : m_tracingName);
 #endif
         visitor->mark(m_raw);
     }
 
     RawPtr<T> release()
@@ skipping 192 matching lines @@
     template<typename U>
     Member(const Member<U>& other) : m_raw(other) { }
 
     T* release()
     {
         T* result = m_raw;
         m_raw = nullptr;
         return result;
     }
 
-    template<typename U>
-    U* as() const
-    {
-        return static_cast<U*>(m_raw);
-    }
-
     bool operator!() const { return !m_raw; }
 
     operator T*() const { return m_raw; }
 
     T* operator->() const { return m_raw; }
     T& operator*() const { return *m_raw; }
     template<typename U>
     operator RawPtr<U>() const { return m_raw; }
 
     template<typename U>
@@ skipping 605 matching lines @@
 template<typename T>
 struct ParamStorageTraits<RawPtr<T>> : public PointerParamStorageTraits<T*, blink::IsGarbageCollectedType<T>::value> {
 };
 
 template<typename T>
 PassRefPtr<T> adoptRef(blink::RefCountedGarbageCollected<T>*) = delete;
 
 } // namespace WTF
 
 #endif