Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/dom/TreeScopeAdopter.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 14 matching lines @@
 #ifndef TreeScopeAdopter_h
 #define TreeScopeAdopter_h
 
 #include "core/dom/Node.h"
 
 namespace WebCore {
 
 class TreeScope;
 
 class TreeScopeAdopter {
+    STACK_ALLOCATED();
 public:
     TreeScopeAdopter(Node& toAdopt, TreeScope& newScope);
 
     void execute() const { moveTreeToNewScope(m_toAdopt); }
     bool needsScopeChange() const { return m_oldScope != m_newScope; }
 
 #ifdef NDEBUG
     static void ensureDidMoveToNewDocumentWasCalled(Document&) { }
 #else
     static void ensureDidMoveToNewDocumentWasCalled(Document&);
 #endif
 
 private:
     void updateTreeScope(Node&) const;
     void moveTreeToNewScope(Node&) const;
     void moveTreeToNewDocument(Node&, Document& oldDocument, Document& newDocument) const;
     void moveNodeToNewDocument(Node&, Document& oldDocument, Document& newDocument) const;
 
     Node& m_toAdopt;
     TreeScope& m_newScope;
     TreeScope& m_oldScope;

[haraken, 2014/04/25 14:30:32]

Can we use Member<TreeScope> for m_newScope and m_oldScope?

[Mads Ager (chromium), 2014/04/28 09:45:21]

Yes, we can. However, good transition types for these are hard because these are
references (use . instead of ->, would have to change signatures from & to
Member). Therefore, if I were to replace them with Members I would have to ifdef
the entire implementation OR change the references here back to pointers and use
RawPtrWillBeMember. I would prefer to do the latter. However, the references
that are in use here have been introduced recently, so I think we should have a
discussion with the broader team about this before we replace these references
with pointers again. We should talk to the broader Blink community about this
issue at BlinkOn2. :)

Since this is STACK_ALLOCATED the references are safe and therefore I will leave
them for this change.

 };
 
 inline TreeScopeAdopter::TreeScopeAdopter(Node& toAdopt, TreeScope& newScope)
     : m_toAdopt(toAdopt)
     , m_newScope(newScope)
     , m_oldScope(toAdopt.treeScope())
 {
 }
 
 }
 
 #endif