Oilpan: Prepare moving AXObject to heap

Source/modules/accessibility/AXScrollView.cpp

Index: Source/modules/accessibility/AXScrollView.cpp
diff --git a/Source/modules/accessibility/AXScrollView.cpp b/Source/modules/accessibility/AXScrollView.cpp
index 168c8565b53e01fa9d5c29e4ef4415cc859ebf98..96363ad25a042ee97b638b6ae665cc72bf36bbf7 100644
--- a/Source/modules/accessibility/AXScrollView.cpp
+++ b/Source/modules/accessibility/AXScrollView.cpp
@@ -43,18 +43,20 @@ AXScrollView::AXScrollView(FrameView* view, AXObjectCacheImpl* axObjectCache)
 
 AXScrollView::~AXScrollView()
 {
+#if !ENABLE(OILPAN)
     ASSERT(isDetached());
+#endif
 }
 
 void AXScrollView::detach()
 {
     AXObject::detach();
-    m_scrollView = 0;
+    m_scrollView = nullptr;
 }
 
-PassRefPtr<AXScrollView> AXScrollView::create(FrameView* view, AXObjectCacheImpl* axObjectCache)
+PassRefPtrWillBeRawPtr<AXScrollView> AXScrollView::create(FrameView* view, AXObjectCacheImpl* axObjectCache)
 {
-    return adoptRef(new AXScrollView(view, axObjectCache));
+    return adoptRefWillBeNoop(new AXScrollView(view, axObjectCache));
 }
 
 AXObject* AXScrollView::scrollBar(AccessibilityOrientation orientation)
@@ -259,4 +261,12 @@ void AXScrollView::scrollTo(const IntPoint& point) const
         m_scrollView->setScrollPosition(point);
 }
 
+DEFINE_TRACE(AXScrollView)
+{
+    AXObject::trace(visitor);
+    visitor->trace(m_scrollView);
+    visitor->trace(m_horizontalScrollbar);
+    visitor->trace(m_verticalScrollbar);
+}
+
 } // namespace blink