Oilpan: Prepare moving AXObject to heap

Source/modules/accessibility/AXImageMapLink.cpp

 /*
  * Copyright (C) 2008 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 27 matching lines @@
 
 AXImageMapLink::AXImageMapLink(AXObjectCacheImpl& axObjectCache)
     : AXMockObject(axObjectCache)
     , m_areaElement(nullptr)
     , m_mapElement(nullptr)
 {
 }
 
 AXImageMapLink::~AXImageMapLink()
 {
+    ASSERT(!m_areaElement);
+    ASSERT(!m_mapElement);
+}
+
+void AXImageMapLink::detach()
+{
+    AXMockObject::detach();
+    m_areaElement = nullptr;
+    m_mapElement = nullptr;
 }
 
 void AXImageMapLink::detachFromParent()
 {
     AXMockObject::detachFromParent();
     m_areaElement = nullptr;
     m_mapElement = nullptr;
 }
 
-PassRefPtr<AXImageMapLink> AXImageMapLink::create(AXObjectCacheImpl& axObjectCache)
+PassRefPtrWillBeRawPtr<AXImageMapLink> AXImageMapLink::create(AXObjectCacheImpl& axObjectCache)
 {
-    return adoptRef(new AXImageMapLink(axObjectCache));
+    return adoptRefWillBeNoop(new AXImageMapLink(axObjectCache));
 }
 
 AXObject* AXImageMapLink::computeParent() const
 {
     if (m_parent)
         return m_parent;
 
     if (!m_mapElement.get() || !m_mapElement->layoutObject())
         return 0;
 
@@ skipping 64 matching lines @@
         layoutObject = toAXLayoutObject(m_parent)->layoutObject();
     else
         layoutObject = m_mapElement->layoutObject();
 
     if (!layoutObject)
         return LayoutRect();
 
     return m_areaElement->computeRect(layoutObject);
 }
 
+DEFINE_TRACE(AXImageMapLink)
+{
+    visitor->trace(m_areaElement);
+    visitor->trace(m_mapElement);
+    AXMockObject::trace(visitor);
+}
+
 } // namespace blink