Bug 718340 - Don't traverse black windows, r=mccr8,jst

dom/base/nsGlobalWindow.cpp

@@ -1404,8 +1404,9 @@ NS_IMPL_CYCLE_COLLECTING_RELEASE(nsGlobalWindow)
 
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsGlobalWindow)
-  if (tmp->mDoc && nsCCUncollectableMarker::InGeneration(
+  if ((tmp->mDoc && nsCCUncollectableMarker::InGeneration(
-                     cb, tmp->mDoc->GetMarkedCCGeneration())) {
+                      cb, tmp->mDoc->GetMarkedCCGeneration())) ||
+      (nsCCUncollectableMarker::sGeneration && tmp->IsBlack())) {
     return NS_SUCCESS_INTERRUPTED_TRAVERSE;
   }