Avoid a SVG property list-induced leak (Oilpan).

Source/core/svg/SVGPathSeg.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 145 matching lines @@
     static PassRefPtrWillBeRawPtr<SVGPathSeg> create() { ASSERT_NOT_REACHED(); return nullptr; }
     virtual PassRefPtrWillBeRawPtr<SVGPathSeg> clone() = 0;
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     void commitChange();
 
 private:
     RawPtrWillBeMember<SVGPropertyBase> m_ownerList;
-    RawPtrWillBeMember<SVGElement> m_contextElement;
+    GC_PLUGIN_IGNORE("528275")
+    SVGElement* m_contextElement;
 };
 
 class SVGPathSegSingleCoordinate : public SVGPathSeg {
 public:
     float x() const { return m_x; }
     void setX(float x)
     {
         m_x = x;
         commitChange();
     }
@@ skipping 14 matching lines @@
     }
 
 private:
     float m_x;
     float m_y;
 };
 
 } // namespace blink
 
 #endif // SVGPathSeg_h