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

Source/WebCore/bindings/dart/DartIsolate.h

 // Copyright 2012, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //    * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //    * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef DartIsolate_h
 #define DartIsolate_h
 
 #include <dart_api.h>
+#include <wtf/HashMap.h>
 #include <wtf/RefPtr.h>
 #include <wtf/ThreadSafeRefCounted.h>
 
 namespace WebCore {
 
 class DartIsolate : public ThreadSafeRefCounted<DartIsolate> {
     WTF_MAKE_NONCOPYABLE(DartIsolate);
 public:
     static PassRefPtr<DartIsolate> create(Dart_Isolate isolate)
     {
@@ skipping 23 matching lines @@
 
         ~Scope()
         {
             m_isolate->exit();
         }
 
     private:
         RefPtr<DartIsolate> m_isolate;
     };
 
+    Dart_Handle createWeakPersistentHandle(Dart_Handle object, void* peer, Dart_WeakPersistentHandleFinalizer);
+
 private:
     DartIsolate(Dart_Isolate);
 
     Dart_Isolate m_isolate;
+
+    static void weakCallbackWrapper(Dart_Handle object, void* peer);

[Anton Muhin, 2012/03/28 18:03:23]

do you really need a map here?  it looks like all you need is to be able to
iterate over all the elements and remove an element, couldn't you use doubly
linked list?

[podivilov, 2012/03/28 18:20:05]

I will need to dispose persistent handles in some cases, e.g. for inspected
values.

+
+    struct WeakCallbackData
+    {
+        WeakCallbackData()
+            : peer(0)
+            , weakCallback(0)
+        {
+        }
+
+        WeakCallbackData(void* peer, Dart_WeakPersistentHandleFinalizer weakCallback)
+            : peer(peer)
+            , weakCallback(weakCallback)
+        {
+        }
+
+        void* peer;
+        Dart_WeakPersistentHandleFinalizer weakCallback;
+    };
+    typedef HashMap<Dart_Handle, WeakCallbackData> WeakCallbackMap;
+    WeakCallbackMap m_weakCallbackMap;
 };
 
 
 
 }
 
 #endif // DartIsolate_h