Backed out changeset e94dceac8090 (bug 1385181) for causing bug 1386011 (CCov build bustage) a=bustage

MozReview-Commit-ID: BK2XP0pcoE8

js/public/HashTable.h

@@ -1772,7 +1772,9 @@ class HashTable : private AllocPolicy
         if (!EnsureHash<HashPolicy>(l))
             return AddPtr();
         HashNumber keyHash = prepareHash(l);
-        return AddPtr(lookup(l, keyHash, sCollisionBit), *this, keyHash);
+        Entry& entry = lookup(l, keyHash, sCollisionBit);
+        AddPtr p(entry, *this, keyHash);
+        return p;
     }
 
     template <typename... Args>