From 24bdf2ca796b675cd58e7ebd96103e6752559887 Mon Sep 17 00:00:00 2001
From: Justin Lebar <justin.lebar@gmail.com>
Date: Mon, 3 Oct 2011 12:35:32 -0400
Subject: [PATCH] Bug 686345 - Don't subtract from our count of canvas's memory
 if we never added to the count. r=jmuizelaar

---
 content/canvas/src/nsCanvasRenderingContext2D.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/content/canvas/src/nsCanvasRenderingContext2D.cpp b/content/canvas/src/nsCanvasRenderingContext2D.cpp
index 51ed63c91e2..8281a80c946 100644
--- a/content/canvas/src/nsCanvasRenderingContext2D.cpp
+++ b/content/canvas/src/nsCanvasRenderingContext2D.cpp
@@ -852,7 +852,7 @@ nsCanvasRenderingContext2D::Reset()
 
     // only do this for non-docshell created contexts,
     // since those are the ones that we created a surface for
-    if (mValid && !mDocShell)
+    if (mValid && !mDocShell && mSurface)
         gCanvasMemoryUsed -= mWidth * mHeight * 4;
 
     mSurface = nsnull;