From 1fc4b4ee5dcbc7a6fb2fba2116da966d1795d2b2 Mon Sep 17 00:00:00 2001
From: Georg Koppen <gk@torproject.org>
Date: Mon, 29 May 2017 13:31:07 +0000
Subject: [PATCH] Bug 21972: about:support is partially broken

---
 toolkit/modules/Troubleshoot.jsm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/toolkit/modules/Troubleshoot.jsm b/toolkit/modules/Troubleshoot.jsm
index cc545b4c403ac..364d5e1e94741 100644
--- a/toolkit/modules/Troubleshoot.jsm
+++ b/toolkit/modules/Troubleshoot.jsm
@@ -469,8 +469,11 @@ var dataProviders = {
 
         // Eagerly free resources.
         let loseExt = gl.getExtension("WEBGL_lose_context");
-        loseExt.loseContext();
-
+        // This extension is not necessarily available. Check for it. Fixes bug
+        // 21972.
+        if (loseExt) {
+          loseExt.loseContext();
+        }
 
         return contextInfo;
     }
-- 
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