Oilpan: move SVG property hierarchy to the heap.

Source/platform/graphics/filters/Filter.h

Index: Source/platform/graphics/filters/Filter.h
diff --git a/Source/platform/graphics/filters/Filter.h b/Source/platform/graphics/filters/Filter.h
index a8490eacb3b5884dd53dfb2bedd45c86b7323d09..b448733774117de4d42142c4156eb6b851f2cfd2 100644
--- a/Source/platform/graphics/filters/Filter.h
+++ b/Source/platform/graphics/filters/Filter.h
@@ -25,15 +25,15 @@
 #include "platform/geometry/FloatPoint3D.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/IntRect.h"
+#include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
-class PLATFORM_EXPORT Filter : public RefCounted<Filter> {
+class PLATFORM_EXPORT Filter : public RefCountedWillBeGarbageCollectedFinalized<Filter> {
 public:
-    Filter(float scale)
-    : m_scale(scale) { }
     virtual ~Filter() { }
+    virtual void trace(Visitor*) { }
 
     float scale() const { return m_scale; }
     FloatRect mapLocalRectToAbsoluteRect(const FloatRect& rect) const { FloatRect result(rect); result.scale(m_scale); return result; }
@@ -55,6 +55,12 @@ public:
         m_absoluteFilterRegion.scale(m_scale);
     }
 
+protected:
+    explicit Filter(float scale)
+        : m_scale(scale)
+    {
+    }
+
 private:
     float m_scale;
     FloatRect m_absoluteFilterRegion;