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

Source/WebCore/bindings/dart/DartUtilities.cpp

Index: Source/WebCore/bindings/dart/DartUtilities.cpp
diff --git a/Source/WebCore/bindings/dart/DartUtilities.cpp b/Source/WebCore/bindings/dart/DartUtilities.cpp
index 12210b23928436328a770c1f314d37d4f68b1fa6..af5f59e01a7d04c6ffffae3707285edad09980e5 100644
--- a/Source/WebCore/bindings/dart/DartUtilities.cpp
+++ b/Source/WebCore/bindings/dart/DartUtilities.cpp
@@ -262,7 +262,7 @@ static DartDOMData* domDataForIsolate(Dart_Isolate isolate)
 
 static DartDOMData* currentDOMData()
 {
-    return domDataForIsolate(DartIsolate::current()->isolate());
+    return domDataForIsolate(Dart_CurrentIsolate());
 }
 
 void DartUtilities::registerDOMIsolate(Dart_Isolate isolate, PassRefPtr<DartApplicationLoader> applicationLoader, ScriptExecutionContext* context)
@@ -382,6 +382,48 @@ PassRefPtr<ScriptCallStack> DartUtilities::createScriptCallStack()
     return ScriptCallStack::create(wrappedCallFrames);
 }
 
+class DartWeakCallback
+{
+public:
+    DartWeakCallback(void* peer, Dart_WeakPersistentHandleFinalizer weakCallback)
+        : peer(peer)
+        , weakCallback(weakCallback)
+        , object(0)
+    {
+    }
+
+    void* peer;

[Anton Muhin, 2012/03/30 11:36:00]

nit: m_peer, m_weakCallback, etc.?

+    Dart_WeakPersistentHandleFinalizer weakCallback;
+    Dart_Handle object;
+};
+
+static void weakCallbackWrapper(Dart_Handle object, void* peer)
+{
+    DartWeakCallback* callback = static_cast<DartWeakCallback*>(peer);
+    DartUtilities::domDataForCurrentIsolate()->weakCallbacks()->remove(callback);
+    (*callback->weakCallback)(object, callback->peer);
+    delete callback;
+}
+
+Dart_Handle DartUtilities::createWeakPersistentHandle(Dart_Handle object, void* peer, Dart_WeakPersistentHandleFinalizer weakCallback)
+{
+    DartWeakCallback* callback = new DartWeakCallback(peer, weakCallback);
+    callback->object = Dart_NewWeakPersistentHandle(object, callback, &weakCallbackWrapper);
+    domDataForCurrentIsolate()->weakCallbacks()->add(callback);
+    return callback->object;
+}
+
+void DartUtilities::disposeWeakPersistentHandles()
+{
+    DartWeakCallbacks* weakCallbacks = domDataForCurrentIsolate()->weakCallbacks();
+    for (DartWeakCallbacks::iterator it = weakCallbacks->begin(); it != weakCallbacks->end(); ++it) {
+        DartWeakCallback* callback = *it;
+        (*callback->weakCallback)(callback->object, callback->peer);
+        delete callback;
+    }
+    weakCallbacks->clear();
+}
+
 const uint8_t* DartUtilities::fullSnapshot()
 {
     static const uint8_t snapshotBuffer[] = {