Dartium support for manual custom element upgrades.

Source/bindings/dart/DartCustomElementWrapper.h

Index: Source/bindings/dart/DartCustomElementWrapper.h
diff --git a/Source/bindings/dart/DartCustomElementWrapper.h b/Source/bindings/dart/DartCustomElementWrapper.h
index e74bc47178f577fde57e248146ed0039f0353bb6..bfe230a6294e40b463a937a0ded540636ab6b317 100644
--- a/Source/bindings/dart/DartCustomElementWrapper.h
+++ b/Source/bindings/dart/DartCustomElementWrapper.h
@@ -45,6 +45,8 @@ class DartCustomElementWrapper {
 public:
     static Dart_Handle upgradeDartWrapper(ElementType*, Dart_Handle (*createSpecificWrapper)(DartDOMData*, ElementType*));
 
+    static Dart_Handle changeElementWrapper(Dart_Handle element, Dart_Handle wrapperType);
+
     static void initializeCustomElement(Dart_Handle wrapper, Dart_Handle& exception);
 
 private:
@@ -53,6 +55,8 @@ private:
     friend Dart_Handle createDartHTMLWrapper(DartDOMData*, HTMLElement*);
     friend Dart_Handle createDartSVGWrapper(DartDOMData*, SVGElement*);
 
+    static Dart_Handle swapElementWrapper(DartDOMData*, HTMLElement*, Dart_Handle wrapperType, intptr_t nativeClassId);
+
     static Dart_Handle wrap(PassRefPtr<ElementType>, Dart_Handle (*createSpecificWrapper)(DartDOMData*, ElementType*));
 };