Oilpan: move DOMImplementation to the heap.

Source/core/dom/DOMImplementation.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, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 22 matching lines @@
 class CSSStyleSheet;
 class Document;
 class DocumentInit;
 class DocumentType;
 class ExceptionState;
 class LocalFrame;
 class HTMLDocument;
 class KURL;
 class XMLDocument;
 
-class DOMImplementation : public ScriptWrappable {
-    WTF_MAKE_FAST_ALLOCATED;
+class DOMImplementation FINAL : public NoBaseWillBeGarbageCollectedFinalized<DOMImplementation>, public ScriptWrappable {
+    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
 public:
-    static PassOwnPtr<DOMImplementation> create(Document& document) { return adoptPtr(new DOMImplementation(document)); }
+    static PassOwnPtrWillBeRawPtr<DOMImplementation> create(Document* document)

[tkent, 2014/05/07 23:43:20]

Why do you change the argument type from a reference to a pointer?

[sof, 2014/05/08 05:24:13]

At the single call site, converting a pointer into a reference, only to convert
it back into a pointer (Member) is making work for questionable gain. Are there
some to be had?

[tkent, 2014/05/08 06:09:16]

Even in such case, the reference still has benefit as ever. It tells us that the
variable can't be null without any words.

[sof, 2014/05/08 06:14:53]

I'll switch back, but the lack of reviewing consistency is sub-optimal. i.e.,
asked in other ongoing dom/ reviews to switch away from refs in create()
signatures.

+    {
+        return adoptPtrWillBeNoop(new DOMImplementation(document));
+    }
 
-    void ref() { m_document.ref(); }
-    void deref() { m_document.deref(); }
-    Document& document() const { return m_document; }
+#if !ENABLE(OILPAN)
+    void ref() { m_document->ref(); }
+    void deref() { m_document->deref(); }
+#endif
+    Document& document() const { return *m_document.get(); }
 
     // DOM methods & attributes for DOMImplementation
     static bool hasFeature(const String& feature, const String& version);
     bool hasFeatureForBindings(const String& feature, const String& version);
     PassRefPtr<DocumentType> createDocumentType(const AtomicString& qualifiedName, const String& publicId, const String& systemId, ExceptionState&);
     PassRefPtr<XMLDocument> createDocument(const AtomicString& namespaceURI, const AtomicString& qualifiedName, DocumentType*, ExceptionState&);
 
     // From the HTMLDOMImplementation interface
     PassRefPtr<HTMLDocument> createHTMLDocument(const String& title);
 
     // Other methods (not part of DOM)
     static PassRefPtr<Document> createDocument(const String& mimeType, LocalFrame*, const KURL&, bool inViewSourceMode);
     static PassRefPtr<Document> createDocument(const String& mimeType, const DocumentInit&, bool inViewSourceMode);
 
     static bool isXMLMIMEType(const String&);
     static bool isTextMIMEType(const String&);
     static bool isJSONMIMEType(const String&);
 
+    void trace(Visitor*);
+
 private:
-    explicit DOMImplementation(Document&);
+    explicit DOMImplementation(Document*);
 
-    Document& m_document;
+    RawPtrWillBeMember<Document> m_document;
 };
 
 } // namespace WebCore
 
 #endif