Oilpan: Prepare moving AXObject to heap

Source/modules/accessibility/AXTableColumn.h

 /*
  * 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 26 matching lines @@
 
 class AXObjectCacheImpl;
 class LayoutTableSection;
 
 class MODULES_EXPORT AXTableColumn final : public AXMockObject {
 
 private:
     explicit AXTableColumn(AXObjectCacheImpl&);
 
 public:
-    static PassRefPtr<AXTableColumn> create(AXObjectCacheImpl&);
+    static PassRefPtrWillBeRawPtr<AXTableColumn> create(AXObjectCacheImpl&);
     virtual ~AXTableColumn();
 
     // retrieves the topmost "column" header (th)
     AXObject* headerObject();
     // retrieves the "column" headers (th, scope) from top to bottom
     void headerObjectsForColumn(AccessibilityChildrenVector&);
 
     virtual AccessibilityRole roleValue() const override { return ColumnRole; }
 
     void setColumnIndex(int columnIndex) { m_columnIndex = columnIndex; }
@@ skipping 10 matching lines @@
 
     virtual bool isTableCol() const override { return true; }
     virtual bool computeAccessibilityIsIgnored(IgnoredReasons* = nullptr) const override;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXTableColumn, isTableCol());
 
 } // namespace blink
 
 #endif // AXTableColumn_h