Bug 630588: use PRInt32 as iterator variable in nsGlobalWindow::FireDelayedDOMEvents to fix build warning. r=jst a=jst

dom/base/nsGlobalWindow.cpp

@@ -8414,7 +8414,7 @@ nsGlobalWindow::FireDelayedDOMEvents()
 {
   FORWARD_TO_INNER(FireDelayedDOMEvents, (), NS_ERROR_UNEXPECTED);
 
-  for (PRUint32 i = 0; i < mPendingStorageEvents.Count(); ++i) {
+  for (PRInt32 i = 0; i < mPendingStorageEvents.Count(); ++i) {
     Observe(mPendingStorageEvents[i], "dom-storage2-changed", nsnull);
   }