Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGLinearGradientElement.cpp

Index: Source/core/svg/SVGLinearGradientElement.cpp
diff --git a/Source/core/svg/SVGLinearGradientElement.cpp b/Source/core/svg/SVGLinearGradientElement.cpp
index 17ffb0bf7753ebc6f36f1bd14ff9d41211a22b6a..2b98ab30e34508e472147da1b46430050ec72e02 100644
--- a/Source/core/svg/SVGLinearGradientElement.cpp
+++ b/Source/core/svg/SVGLinearGradientElement.cpp
@@ -48,6 +48,15 @@ inline SVGLinearGradientElement::SVGLinearGradientElement(Document& document)
     addToPropertyMap(m_y2);
 }
 
+void SVGLinearGradientElement::trace(Visitor* visitor)
+{
+    visitor->trace(m_x1);
+    visitor->trace(m_y1);
+    visitor->trace(m_x2);
+    visitor->trace(m_y2);
+    SVGGradientElement::trace(visitor);
+}
+
 DEFINE_NODE_FACTORY(SVGLinearGradientElement)
 
 bool SVGLinearGradientElement::isSupportedAttribute(const QualifiedName& attrName)