Oilpan: move SVG property hierarchy to the heap.

Source/core/svg/SVGScriptElement.h

Index: Source/core/svg/SVGScriptElement.h
diff --git a/Source/core/svg/SVGScriptElement.h b/Source/core/svg/SVGScriptElement.h
index 3b728a17568858cc14265b0a2b4551dfd636fdf5..203b9c8380a12ea0a09ee81e06ff58004a188979 100644
--- a/Source/core/svg/SVGScriptElement.h
+++ b/Source/core/svg/SVGScriptElement.h
@@ -27,6 +27,7 @@
 #include "core/svg/SVGAnimatedString.h"
 #include "core/svg/SVGElement.h"
 #include "core/svg/SVGURIReference.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
@@ -37,6 +38,7 @@ class SVGScriptElement final
     , public SVGURIReference
     , public ScriptLoaderClient {
     DEFINE_WRAPPERTYPEINFO();
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(SVGScriptElement);
 public:
     static PassRefPtrWillBeRawPtr<SVGScriptElement> create(Document&, bool wasInsertedByParser);