Bug 530373 followup. Fix build bustage.

content/base/src/nsContentUtils.cpp

@@ -4278,7 +4278,8 @@ nsContentUtils::GetLocalizedEllipsis()
   static PRUnichar sBuf[4] = { 0, 0, 0, 0 };
   if (!sBuf[0]) {
     nsAutoString tmp(GetLocalizedStringPref("intl.ellipsis"));
-    PRUint32 len = NS_MIN(tmp.Length(), NS_ARRAY_LENGTH(sBuf) - 1);
+    PRUint32 len = NS_MIN(PRUint32(tmp.Length()),
+                          PRUint32(NS_ARRAY_LENGTH(sBuf) - 1));
     CopyUnicodeTo(tmp, 0, sBuf, len);
     if (!sBuf[0])
       sBuf[0] = PRUnichar(0x2026);