Oilpan: Make the Node hierarchy RefCountedGarbageCollected instead of TreeShared.

Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 35 matching lines @@
 struct SameSizeAsShadowRoot : public DocumentFragment, public TreeScope, public DoublyLinkedListNode<ShadowRoot> {
     void* pointers[3];
     unsigned countersAndFlags[1];
 };
 
 COMPILE_ASSERT(sizeof(ShadowRoot) == sizeof(SameSizeAsShadowRoot), shadowroot_should_stay_small);
 
 ShadowRoot::ShadowRoot(Document& document, ShadowRootType type)
     : DocumentFragment(0, CreateShadowRoot)
     , TreeScope(*this, document)
-    , m_prev(0)
-    , m_next(0)
+    , m_prev(nullptr)
+    , m_next(nullptr)
     , m_numberOfStyles(0)
     , m_type(type)
     , m_registeredWithParentShadowRoot(false)
     , m_descendantInsertionPointsIsValid(false)
 {
     ScriptWrappable::init(this);
 }
 
 ShadowRoot::~ShadowRoot()
 {
+#if !ENABLE(OILPAN)
     ASSERT(!m_prev);
     ASSERT(!m_next);
 
-#if !ENABLE(OILPAN)
     if (m_shadowRootRareData && m_shadowRootRareData->styleSheets())
         m_shadowRootRareData->styleSheets()->detachFromDocument();
 
     document().styleEngine()->didRemoveShadowRoot(this);
-#endif
 
-#if !ENABLE(OILPAN)
     // We cannot let ContainerNode destructor call willBeDeletedFromDocument()
     // for this ShadowRoot instance because TreeScope destructor
     // clears Node::m_treeScope thus ContainerNode is no longer able
     // to access it Document reference after that.
     willBeDeletedFromDocument();
-#endif
 
     // We must remove all of our children first before the TreeScope destructor
     // runs so we don't go through TreeScopeAdopter for each child with a
     // destructed tree scope in each descendant.
     removeDetachedChildren();
+#endif
 
     // We must call clearRareData() here since a ShadowRoot class inherits TreeScope
     // as well as Node. See a comment on TreeScope.h for the reason.
     if (hasRareData())
         clearRareData();
 }
 
 void ShadowRoot::dispose()
 {
+#if !ENABLE(OILPAN)
     removeDetachedChildren();

[haraken, 2014/05/06 04:20:16]

The same question as before, but I got confused about when
removeDetachedChildrenInContainer is called in the Node hierarchy... :)

[Mads Ager (chromium), 2014/05/06 08:26:00]

removeDetachedChildren was only needed with RefCounting. Nothing to be done
here.

+#endif
 }
 
 ShadowRoot* ShadowRoot::olderShadowRootForBindings() const
 {
     ShadowRoot* older = olderShadowRoot();
     while (older && !older->shouldExposeToBindings())
         older = older->olderShadowRoot();
     ASSERT(!older || older->shouldExposeToBindings());
     return older;
 }
@@ skipping 222 matching lines @@
 StyleSheetList* ShadowRoot::styleSheets()
 {
     if (!ensureShadowRootRareData()->styleSheets())
         m_shadowRootRareData->setStyleSheets(StyleSheetList::create(this));
 
     return m_shadowRootRareData->styleSheets();
 }
 
 void ShadowRoot::trace(Visitor* visitor)
 {
+    visitor->trace(m_prev);
+    visitor->trace(m_next);
     visitor->trace(m_shadowRootRareData);
     TreeScope::trace(visitor);
     DocumentFragment::trace(visitor);
 }
 
 }