layout/style/test/test_mql_event_listener_leaks.html

   1 <!--
   2   Any copyright is dedicated to the Public Domain.
   3   http://creativecommons.org/publicdomain/zero/1.0/
   4 -->
   5 <!DOCTYPE HTML>
   6 <html>
   7 <head>
   8   <title>Bug 1450271 - Test MediaQueryList event listener leak conditions</title>
   9   <script src="/tests/SimpleTest/SimpleTest.js"></script>
  10   <script type="text/javascript" src="/tests/dom/events/test/event_leak_utils.js"></script>
  11   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
  12 </head>
  13 <body>
  14 <script class="testbody" type="text/javascript">
  15 // Manipulate MediaQueryList.  Its important here that we create a
  16 // listener callback from the DOM objects back to the frame's global
  17 // in order to exercise the leak condition.
  18 async function useMediaQuery(contentWindow) {
  19   contentWindow.messageCount = 0;
  20
  21   let mql = contentWindow.matchMedia("(max-width: 600px)");
  22   mql.onchange = _ => {
  23     contentWindow.mediaCount += 1;
  24   };
  25 }
  26
  27 async function runTest() {
  28   try {
  29     await checkForEventListenerLeaks("MediaQueryList", useMediaQuery);
  30   } catch (e) {
  31     ok(false, e);
  32   } finally {
  33     SimpleTest.finish();
  34   }
  35 }
  36
  37 SimpleTest.waitForExplicitFinish();
  38 addEventListener("load", runTest, { once: true });
  39 </script>
  40 </pre>
  41 </body>
  42 </html>
  43