Cap chrome.mdns.onServiceList listeners per extension at 10

chrome/test/data/extensions/api_test/mdns/api-packaged-apps/register_too_many_listeners.js

Index: chrome/test/data/extensions/api_test/mdns/api-packaged-apps/register_too_many_listeners.js
diff --git a/chrome/test/data/extensions/api_test/mdns/api-packaged-apps/register_too_many_listeners.js b/chrome/test/data/extensions/api_test/mdns/api-packaged-apps/register_too_many_listeners.js
new file mode 100644
index 0000000000000000000000000000000000000000..ce110639dc710ccbcb5ebb0f09b82cff61c31e3a
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/mdns/api-packaged-apps/register_too_many_listeners.js
@@ -0,0 +1,43 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.

[mark a. foltz, 2015/03/30 17:44:57]

Update copyright

[Red Daly, 2015/03/30 20:28:34]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+chrome.app.runtime.onLaunched.addListener(function() {
+  chrome.test.runTests([
+    function registerListeners() {
+      // Add the maximum number of listeners.
+      var listeners = [];
+      var MAX_LISTENERS = 10;
+      for (var i = 0; i < MAX_LISTENERS; i++) {
+        listeners.push({
+          'callback': function() {},
+          'filter': {'serviceType': '_' + i + '._tcp.local'}
+        });
+      }
+      listeners.forEach(function(x) {
+        chrome.mdns.onServiceList.addListener(x.callback, x.filter);
+      });
+
+      var removeAllListeners = function() {
+      };
+
+      // Now try adding one more.  This should exceed the limit.
+      var failedToAddLast = false;
+      try {
+        chrome.mdns.onServiceList.addListener(
+            function() {},
+            {'serviceType': '_one_too_many._tcp.local'});
+      } catch (x) {
+        failedToAddLast = true;

[mark a. foltz, 2015/03/30 17:44:57]

Assert that the exception is actually for too many listeners?

[Red Daly, 2015/03/30 20:28:34]

Done.  (This depends on string matching the error message.  If there's another
way you think we could specify the error type, I can modify EventImpl
accordingly.)

+      }
+      chrome.test.assertBool(
+          true, failedToAddLast,
+          "there should be an error when adding the 11th listener");
+
+      listeners.forEach(function(x) {
+        chrome.mdns.onServiceList.removeListener(x.callback, x.filter);
+      });
+      chrome.test.notifyPass();
+    }
+  ]);
+});