Implement Harmony sets and maps.

src/handles.h

Index: src/handles.h
diff --git a/src/handles.h b/src/handles.h
index 358f1b5db2b5e9017d56b243c5c3a69819102ed1..2607c4a903133d73c44408f5c469606fffc5267c 100644
--- a/src/handles.h
+++ b/src/handles.h
@@ -341,6 +341,12 @@ Handle<Object> SetPrototype(Handle<JSFunction> function,
 
 Handle<Object> PreventExtensions(Handle<JSObject> object);
 
+Handle<ObjectHashSet> ObjectHashSetAdd(Handle<ObjectHashSet> table,
+                                       Handle<Object> key);
+
+Handle<ObjectHashSet> ObjectHashSetRemove(Handle<ObjectHashSet> table,
+                                          Handle<Object> key);
+
 Handle<ObjectHashTable> PutIntoObjectHashTable(Handle<ObjectHashTable> table,
                                                Handle<JSReceiver> key,
                                                Handle<Object> value);