Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGMaskElement.h

Index: Source/core/svg/SVGMaskElement.h
diff --git a/Source/core/svg/SVGMaskElement.h b/Source/core/svg/SVGMaskElement.h
index a0345bc8ab1568daae9781c41916d5afe84e54ca..87ad79125071ec1db21dd736f6f8fe06ce8bd95e 100644
--- a/Source/core/svg/SVGMaskElement.h
+++ b/Source/core/svg/SVGMaskElement.h
@@ -27,12 +27,14 @@
 #include "core/svg/SVGElement.h"
 #include "core/svg/SVGTests.h"
 #include "core/svg/SVGUnitTypes.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
 class SVGMaskElement final : public SVGElement,
                              public SVGTests {
     DEFINE_WRAPPERTYPEINFO();
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(SVGMaskElement);
 public:
     DECLARE_NODE_FACTORY(SVGMaskElement);
 
@@ -43,6 +45,8 @@ public:
     SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>* maskUnits() { return m_maskUnits.get(); }
     SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType>* maskContentUnits() { return m_maskContentUnits.get(); }
 
+    virtual void trace(Visitor*) override;
+
 private:
     explicit SVGMaskElement(Document&);
 
@@ -58,12 +62,12 @@ private:
 
     virtual bool selfHasRelativeLengths() const override;
 
-    RefPtr<SVGAnimatedLength> m_x;
-    RefPtr<SVGAnimatedLength> m_y;
-    RefPtr<SVGAnimatedLength> m_width;
-    RefPtr<SVGAnimatedLength> m_height;
-    RefPtr<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_maskUnits;
-    RefPtr<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_maskContentUnits;
+    RefPtrWillBeMember<SVGAnimatedLength> m_x;
+    RefPtrWillBeMember<SVGAnimatedLength> m_y;
+    RefPtrWillBeMember<SVGAnimatedLength> m_width;
+    RefPtrWillBeMember<SVGAnimatedLength> m_height;
+    RefPtrWillBeMember<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_maskUnits;
+    RefPtrWillBeMember<SVGAnimatedEnumeration<SVGUnitTypes::SVGUnitType> > m_maskContentUnits;
 };
 
 } // namespace blink