Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/css/resolver/StyleSharingDepthScope.h

 // Copyright 2016 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 StyleSharingDepthScope_h
 #define StyleSharingDepthScope_h
 
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Node.h"
 
 namespace blink {
 
 // Maintains the style sharing depth in the style resolver.
 class StyleSharingDepthScope final {
     STACK_ALLOCATED();
 public:
     explicit StyleSharingDepthScope(Node& parent)
         : m_resolver(parent.document().styleResolver())
     {
         m_resolver->increaseStyleSharingDepth();
     }
 
     ~StyleSharingDepthScope()
     {
         m_resolver->decreaseStyleSharingDepth();
     }
 
 private:
-    RawPtrWillBeMember<StyleResolver> m_resolver;
+    Member<StyleResolver> m_resolver;
 };
 
 } // namespace blink
 
 #endif // StyleSharingDepthScope_h