From c11ce45a79f0d97a2d9d02a822bc7af1a6269830 Mon Sep 17 00:00:00 2001
From: James Willcox <jwillcox@mozilla.com>
Date: Fri, 9 Aug 2013 17:19:21 -0400
Subject: [PATCH] Bug 902426 - Do not allow duplicate entries in the CRC2D
 demotion list r=mattwoodrow

--HG--
extra : rebase_source : c7c344f2b88065f46c06c99fa0bf868367b6b9ab
---
 content/canvas/src/CanvasRenderingContext2D.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/content/canvas/src/CanvasRenderingContext2D.cpp b/content/canvas/src/CanvasRenderingContext2D.cpp
index 52003f1a5c94..bf500031d699 100644
--- a/content/canvas/src/CanvasRenderingContext2D.cpp
+++ b/content/canvas/src/CanvasRenderingContext2D.cpp
@@ -797,6 +797,10 @@ CanvasRenderingContext2D::DemoteOldestContextIfNecessary()
 void
 CanvasRenderingContext2D::AddDemotableContext(CanvasRenderingContext2D* context)
 {
+  std::vector<CanvasRenderingContext2D*>::iterator iter = std::find(DemotableContexts().begin(), DemotableContexts().end(), context);
+  if (iter != DemotableContexts().end())
+    return;
+
   DemotableContexts().push_back(context);
 }