Add WeakMap to v8.h

test/cctest/test-weaksets.cc

Index: test/cctest/test-weaksets.cc
diff --git a/test/cctest/test-weaksets.cc b/test/cctest/test-weaksets.cc
index 299cc92e9b28676db30df4d4e90f1713a842d85b..60f2d45dc358d8c186bc139a943763db21e39f38 100644
--- a/test/cctest/test-weaksets.cc
+++ b/test/cctest/test-weaksets.cc
@@ -58,11 +58,7 @@ static Handle<JSWeakSet> AllocateJSWeakSet(Isolate* isolate) {
 static void PutIntoWeakSet(Handle<JSWeakSet> weakset,
                            Handle<JSObject> key,
                            Handle<Object> value) {
-  Handle<ObjectHashTable> table = ObjectHashTable::Put(
-      Handle<ObjectHashTable>(ObjectHashTable::cast(weakset->table())),
-      Handle<JSObject>(JSObject::cast(*key)),
-      value);
-  weakset->set_table(*table);
+  Runtime::WeakCollectionSet(weakset, key, value);
 }
 
 static int NumberOfWeakCalls = 0;