From 270cd1ba97836f049f4218cb62becc836580f394 Mon Sep 17 00:00:00 2001
From: Mats Palmgren <matspal@gmail.com>
Date: Sun, 13 Jul 2014 13:01:43 +0000
Subject: [PATCH] Bug 637242, patch 1 of 3: Fix ref-counting bug.  r=dbaron

---
 layout/style/nsRuleNode.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index f96a106d7604..bd8f9ed767fa 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -8955,7 +8955,7 @@ nsRuleNode::Sweep()
       PLDHashTable *children = ChildrenHash();
       uint32_t oldChildCount = children->entryCount;
       PL_DHashTableEnumerate(children, SweepRuleNodeChildren, nullptr);
-      childrenDestroyed = children->entryCount - oldChildCount;
+      childrenDestroyed = oldChildCount - children->entryCount;
     } else {
       childrenDestroyed = 0;
       for (nsRuleNode **children = ChildrenListPtr(); *children; ) {