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

Source/WebCore/bindings/dart/DartDOMWrapper.h

Index: Source/WebCore/bindings/dart/DartDOMWrapper.h
diff --git a/Source/WebCore/bindings/dart/DartDOMWrapper.h b/Source/WebCore/bindings/dart/DartDOMWrapper.h
index 180c433d4ab042c5f48ca49c7ce3099d7651828d..cb17b9383746a9c90a4ff1fc930f4759a9bbd2e8 100644
--- a/Source/WebCore/bindings/dart/DartDOMWrapper.h
+++ b/Source/WebCore/bindings/dart/DartDOMWrapper.h
@@ -317,7 +317,7 @@ public:
     static Dart_Handle newWrapper(const char* className, WebkitClass* domObject)
     {
         Dart_Handle wrapper = instantiateWrapper(className);
-        installNativePointers(domObject, wrapper);
+        writeNativePointer(wrapper, kNativeImplementationIndex, domObject);
         return wrapper;
     }
 
@@ -350,10 +350,9 @@ public:
     {
         ASSERT(domObject);
         domObject->ref();
-        installNativePointers(domObject, wrapper);
+        writeNativePointer(wrapper, kNativeImplementationIndex, domObject);
 
-        // FIXME: make persistent handle weak and deref domObject in weak callback.
-        Dart_Handle persistentWrapperHandle = Dart_NewPersistentHandle(wrapper);
+        Dart_Handle persistentWrapperHandle = DartUtilities::createWeakPersistentHandle(wrapper, domObject, &wrapperWeakCallback<WebkitClass>);
 
         DartDOMMap* domMap = DartUtilities::domMapForCurrentIsolate();
         ASSERT(!domMap->contains(domObject));
@@ -374,8 +373,6 @@ public:
         return reinterpret_cast<typename BindingsClass::NativeType*>(nativePointer);
     }
 
-    static void derefDOMObject(Dart_Handle wrapper, void* domObject);
-
     template <class WebkitClass>
     static WebkitClass* receiver(Dart_NativeArguments args)
     {
@@ -412,7 +409,6 @@ public:
 private:
     enum NativeFieldIndices {
         kNativeImplementationIndex = 0,
-        kDerefObjectFunctionIndex,
         kNativeFieldCount
     };
 
@@ -437,30 +433,16 @@ private:
         return reinterpret_cast<void*>(value);
     }
 
-    template <class WebkitClass>
-    static void installNativePointers(WebkitClass* domObject, Dart_Handle wrapper)
-    {
-        ASSERT(domObject);
-        DerefObjectFunction derefObjectFunction = &DartDOMWrapper::derefObject<WebkitClass>;
-        writeNativePointer(wrapper, kNativeImplementationIndex, domObject);
-        writeNativePointer(wrapper, kDerefObjectFunctionIndex, reinterpret_cast<void*>(derefObjectFunction));
-    }
-
-    typedef void (*DerefObjectFunction)(void*);
-
     template<typename T>
-    static void derefObject(void* pointer)
+    static void wrapperWeakCallback(Dart_Handle, void* domObject)
     {
-        static_cast<T*>(pointer)->deref();
+        DartDOMMap* domMap = DartUtilities::domMapForCurrentIsolate();
+        ASSERT(domMap->contains(domObject));
+        domMap->remove(domObject);
+        static_cast<T*>(domObject)->deref();
     }
 };
 
-template<>
-inline void DartDOMWrapper::derefObject<NPObject>(void*)
-{
-    // FIXME: proper deref.
-}
-
 // ParameterAdapter.
 
 template <typename Value>