1 files changed, 43 insertions, 0 deletions
diff --git a/layout/style/test/test_mql_event_listener_leaks.html b/layout/style/test/test_mql_event_listener_leaks.html
new file mode 100644
index 0000000000..3ceb5412a2
--- /dev/null
+++ b/layout/style/test/test_mql_event_listener_leaks.html
@@ -0,0 +1,43 @@
+<!--
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Bug 1450271 - Test MediaQueryList event listener leak conditions</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="/tests/dom/events/test/event_leak_utils.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<script class="testbody" type="text/javascript">
+// Manipulate MediaQueryList.  Its important here that we create a
+// listener callback from the DOM objects back to the frame's global
+// in order to exercise the leak condition.
+async function useMediaQuery(contentWindow) {
+  contentWindow.messageCount = 0;
+
+  let mql = contentWindow.matchMedia("(max-width: 600px)");
+  mql.onchange = _ => {
+    contentWindow.mediaCount += 1;
+  };
+}
+
+async function runTest() {
+  try {
+    await checkForEventListenerLeaks("MediaQueryList", useMediaQuery);
+  } catch (e) {
+    ok(false, e);
+  } finally {
+    SimpleTest.finish();
+  }
+}
+
+SimpleTest.waitForExplicitFinish();
+addEventListener("load", runTest, { once: true });
+</script>
+</pre>
+</body>
+</html>
+