Oilpan: move RenderObjects off heap.

Source/core/rendering/svg/RenderSVGResourceLinearGradient.h

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) Research In Motion Limited 2010. 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 20 matching lines @@
 class RenderSVGResourceLinearGradient final : public RenderSVGResourceGradient {
 public:
     explicit RenderSVGResourceLinearGradient(SVGLinearGradientElement*);
     virtual ~RenderSVGResourceLinearGradient();
 
     virtual const char* renderName() const override { return "RenderSVGResourceLinearGradient"; }
 
     static const RenderSVGResourceType s_resourceType = LinearGradientResourceType;
     virtual RenderSVGResourceType resourceType() const override { return s_resourceType; }
 
-    virtual SVGUnitTypes::SVGUnitType gradientUnits() const override { return m_attributes.gradientUnits(); }
-    virtual void calculateGradientTransform(AffineTransform& transform) override { transform = m_attributes.gradientTransform(); }
+    virtual SVGUnitTypes::SVGUnitType gradientUnits() const override { return attributes().gradientUnits(); }
+    virtual void calculateGradientTransform(AffineTransform& transform) override { transform = attributes().gradientTransform(); }
     virtual bool collectGradientAttributes(SVGGradientElement*) override;
     virtual void buildGradient(GradientData*) const override;
 
     FloatPoint startPoint(const LinearGradientAttributes&) const;
     FloatPoint endPoint(const LinearGradientAttributes&) const;
 
-    virtual void trace(Visitor*) override;
+private:
+#if ENABLE(OILPAN)
+    // FIXME: Oilpan: the RenderObject hierarchy isn't on the heap, but
+    // the SVG property hierarchy is. And the two meet here, so keep a
+    // persistent reference to the SVG part object by way of a heap-allocated
+    // wrapper object.
+    Persistent<LinearGradientAttributesWrapper> m_attributesWrapper;
 
-private:
+    LinearGradientAttributes& mutableAttributes() { return m_attributesWrapper->attributes(); }
+    const LinearGradientAttributes& attributes() const { return m_attributesWrapper->attributes(); }
+#else
     LinearGradientAttributes m_attributes;
+
+    LinearGradientAttributes& mutableAttributes() { return m_attributes; }
+    const LinearGradientAttributes& attributes() const { return m_attributes; }
+#endif
 };
 
 } // namespace blink
 
 #endif // RenderSVGResourceLinearGradient_h