Fix time out on debug/asan.

Rebase from inbound.

Differential Revision: https://phabricator.services.mozilla.com/D6906

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1483696
gecko-commit: 2b8467cf2d75892a04fae973d5798f8a141c03c4
gecko-integration-branch: autoland
diff --git a/html/browsers/windows/auxiliary-browsing-contexts/opener-setter.html b/html/browsers/windows/auxiliary-browsing-contexts/opener-setter.html
index 85c52e0..e6ff4a1 100644
--- a/html/browsers/windows/auxiliary-browsing-contexts/opener-setter.html
+++ b/html/browsers/windows/auxiliary-browsing-contexts/opener-setter.html
@@ -2,6 +2,7 @@
 <html>
   <head>
     <title>Auxiliary Browing Contexts: window.opener setter</title>
+    <meta name=timeout content=long>
     <script src="/resources/testharness.js"></script>
     <script src="/resources/testharnessreport.js"></script>
     <script src="/common/PrefixedLocalStorage.js"></script>