Clear an extension's filtered events when a context is destroyed.

chrome/test/data/extensions/api_test/events_are_unregistered/page1.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+'use strict';
+
 // Register for events in 4 configurations, then navigate to page2.html, which
 // will notify success and succeed the test on the C++ side. The C++ code
 // asserts that the events have been unregistered.
 
+//
+// Unfiltered events.
+//
+
 // A single listener.
 chrome.browserAction.onClicked.addListener(function() {});
 // Multiple listeners for the same event.
 chrome.runtime.onStartup.addListener(function() {});
 chrome.runtime.onStartup.addListener(function() {});
 // A single listener, which previously had multiple listeners.
-chrome.runtime.onSuspend.addListener(function() {});
-chrome.runtime.onSuspend.addListener(function() {});
-chrome.runtime.onSuspend.removeListener(function() {});
+{
+  let singleListener = function() {};
+  chrome.runtime.onSuspend.addListener(singleListener);
+  chrome.runtime.onSuspend.addListener(function() {});

[Devlin, 2015/07/10 17:57:30]

why some with singleListener and some with function() {}?

[not at google - send to devlin, 2015/07/10 20:39:17]

Listener identity comes from pointer identity. If you pass in (function(){})
then every time that's a new pointer, and therefore a new listener. If you
assign (function(){}) to a variable and then use it more than once, it's the
same listener.

Note that the old code was subtly "wrong" because of this (the assertions were
still correct, just not testing what it was supposed to be testing).

+  chrome.runtime.onSuspend.removeListener(singleListener);
+}
 // No listeners, which previously had listeners (all were removed).
-chrome.runtime.onInstalled.addListener(function() {});
-chrome.runtime.onInstalled.addListener(function() {});
-chrome.runtime.onInstalled.removeListener(function() {});
-chrome.runtime.onInstalled.removeListener(function() {});
+{
+  let listener1 = function() {};
+  let listener2 = function() {};
+  chrome.runtime.onInstalled.addListener(listener1);
+  chrome.runtime.onInstalled.addListener(listener2);
+  chrome.runtime.onInstalled.removeListener(listener1);
+  chrome.runtime.onInstalled.removeListener(listener2);
+}
+
+//
+// Filtered events.
+//
+
+function filterPort(portNumber) {
+  return {url: [{ports: [portNumber]}]};
+}
+
+// A single listener.
+chrome.webNavigation.onBeforeNavigate.addListener(function() {});
+// Multiple, different listeners.
+chrome.webNavigation.onCommitted.addListener(function() {});
+chrome.webNavigation.onCommitted.addListener(function() {});
+// Different listeners with the same filter.
+chrome.webNavigation.onDOMContentLoaded.addListener(
+    function() {}, filterPort(80));
+chrome.webNavigation.onDOMContentLoaded.addListener(
+    function() {}, filterPort(80));
+// Different listeners with different filters, same event added twice.
+{
+  let singleListener = function() {};
+  chrome.webNavigation.onCompleted.addListener(
+      function() {}, filterPort(80));
+  chrome.webNavigation.onCompleted.addListener(
+      function() {}, filterPort(81));
+  chrome.webNavigation.onCompleted.addListener(
+      function() {}, filterPort(81));
+  chrome.webNavigation.onCompleted.addListener(
+      singleListener, filterPort(82));
+  chrome.webNavigation.onCompleted.removeListener(singleListener);
+}
 
 location.assign('page2.html');