Oilpan: Make the Node hierarchy RefCountedGarbageCollected instead of TreeShared.

Source/core/svg/SVGElementInstance.cpp

 /*
  * Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2011 Torch Mobile (Beijing) Co. Ltd. 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 68 matching lines @@
 DEFINE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(SVGElementInstance, correspondingElement(), selectstart);
 DEFINE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(SVGElementInstance, correspondingElement(), submit);
 DEFINE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(SVGElementInstance, correspondingElement(), unload);
 
 PassRefPtr<SVGElementInstance> SVGElementInstance::create(SVGUseElement* correspondingUseElement, SVGUseElement* directUseElement, PassRefPtr<SVGElement> originalElement)
 {
     return adoptRef(new SVGElementInstance(correspondingUseElement, directUseElement, originalElement));
 }
 
 SVGElementInstance::SVGElementInstance(SVGUseElement* correspondingUseElement, SVGUseElement* directUseElement, PassRefPtr<SVGElement> originalElement)
-    : m_parentInstance(0)
+    : m_parentInstance(nullptr)
     , m_correspondingUseElement(correspondingUseElement)
     , m_directUseElement(directUseElement)
-    , m_element(originalElement)
-    , m_previousSibling(0)
-    , m_nextSibling(0)
-    , m_firstChild(0)
-    , m_lastChild(0)
+    , m_element(originalElement.get()) // FIXME: Oilpan: Remove the .get() call.
+    , m_previousSibling(nullptr)
+    , m_nextSibling(nullptr)
+    , m_firstChild(nullptr)
+    , m_lastChild(nullptr)
 {
     ASSERT(m_correspondingUseElement);
     ASSERT(m_element);
     ScriptWrappable::init(this);
 
 #ifndef NDEBUG
     instanceCounter.increment();
 #endif
 }
 
 SVGElementInstance::~SVGElementInstance()
 {
-    // Call detach because we may be deleted directly if we are a child of a detached instance.
-    detach();
-
 #ifndef NDEBUG
     instanceCounter.decrement();
 #endif
 
+#if !ENABLE(OILPAN)
+    // Call detach because we may be deleted directly if we are a child of a detached instance.
+    detach();
     m_element = nullptr;
+#endif
 }
 
 // It's important not to inline removedLastRef, because we don't want to inline the code to
 // delete an SVGElementInstance at each deref call site.
 void SVGElementInstance::removedLastRef()
 {
 #if !ENABLE(OILPAN)
 #if SECURITY_ASSERT_ENABLED
     m_deletionHasBegun = true;
 #endif
@@ skipping 113 matching lines @@
 }
 
 EventTargetData& SVGElementInstance::ensureEventTargetData()
 {
     // EventTarget would use these methods if we were actually using its add/removeEventListener logic.
     // As we're forwarding those calls to the correspondingElement(), no one should ever call this function.
     ASSERT_NOT_REACHED();
     return *eventTargetData();
 }
 
+void SVGElementInstance::trace(Visitor* visitor)
+{
+    visitor->trace(m_parentInstance);
+    visitor->trace(m_element);
+    visitor->trace(m_shadowTreeElement);
+    visitor->trace(m_previousSibling);
+    visitor->trace(m_nextSibling);
+    visitor->trace(m_firstChild);
+    visitor->trace(m_lastChild);
+}
+
 SVGElementInstance::InstanceUpdateBlocker::InstanceUpdateBlocker(SVGElement* targetElement)
     : m_targetElement(targetElement)
 {
     if (m_targetElement)
         m_targetElement->setInstanceUpdatesBlocked(true);
 }
 
 SVGElementInstance::InstanceUpdateBlocker::~InstanceUpdateBlocker()
 {
     if (m_targetElement)
         m_targetElement->setInstanceUpdatesBlocked(false);
 }
 
 }