From 181f3f61e0c263b5b600fcbf19c480818593b223 Mon Sep 17 00:00:00 2001
From: Jean-Yves Avenard <jyavenard@mozilla.com>
Date: Wed, 30 Sep 2015 14:02:48 +1000
Subject: [PATCH] Bug 1207312: P1. Prevent crash when more than one promise is
 rejected. r=bholley

---
 xpcom/threads/MozPromise.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xpcom/threads/MozPromise.h b/xpcom/threads/MozPromise.h
index 160076ad067f..aa02f4974b28 100644
--- a/xpcom/threads/MozPromise.h
+++ b/xpcom/threads/MozPromise.h
@@ -237,6 +237,11 @@ private:
 
     void Reject(const RejectValueType& aRejectValue)
     {
+      if (!mPromise) {
+        // Already rejected.
+        return;
+      }
+
       mPromise->Reject(aRejectValue, __func__);
       mPromise = nullptr;
       mResolveValues.Clear();