DOM wrappers that are not retained from Dart should be collected.

Source/WebCore/bindings/dart/DartDOMWrapper.cpp

Index: Source/WebCore/bindings/dart/DartDOMWrapper.cpp
diff --git a/Source/WebCore/bindings/dart/DartDOMWrapper.cpp b/Source/WebCore/bindings/dart/DartDOMWrapper.cpp
index 3d2b8ad651eb0f66e1af5cc12c8fad4a8a2bb43c..c63f3074f1eb733a51b695955fc17aeeb9ee33c9 100644
--- a/Source/WebCore/bindings/dart/DartDOMWrapper.cpp
+++ b/Source/WebCore/bindings/dart/DartDOMWrapper.cpp
@@ -76,13 +76,6 @@
 
 namespace WebCore {
 
-void DartDOMWrapper::derefDOMObject(Dart_Handle wrapper, void* domObject)
-{
-    ASSERT(domObject == readNativePointer(wrapper, kNativeImplementationIndex));
-    DerefObjectFunction derefObjectFunction = reinterpret_cast<DerefObjectFunction>(readNativePointer(wrapper, kDerefObjectFunctionIndex));
-    (*derefObjectFunction)(domObject);
-}
-
 Dart_Handle DartDOMWrapper::instantiateWrapper(const char* className)
 {
     // FIXME: this all is very ugly, but we're blocked by API here.