Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/page/scrolling/ScrollCustomizationCallbacks.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScrollCustomizationCallbacks_h
 #define ScrollCustomizationCallbacks_h
 
 #include "core/CoreExport.h"
 #include "core/dom/Element.h"
 #include "platform/heap/Handle.h"
@@ skipping 17 matching lines @@
     {
         visitor->trace(m_applyScrollCallbacks);
         visitor->trace(m_distributeScrollCallbacks);
     };
 
 #if !ENABLE(OILPAN)
     void removeCallbacksForElement(Element*);
 #endif
 
 private:
-    using ScrollStateCallbackList = HeapHashMap<RawPtrWillBeWeakMember<Element>, Member<ScrollStateCallback>>;
+    using ScrollStateCallbackList = HeapHashMap<WeakMember<Element>, Member<ScrollStateCallback>>;
     ScrollStateCallbackList m_applyScrollCallbacks;
     ScrollStateCallbackList m_distributeScrollCallbacks;
 };
 
 } // namespace blink
 
 #endif // ScrollCustomizationCallbacks_h