UI refresh of Advanced Font Settings Extension

chrome/common/extensions/docs/examples/api/fontSettings/js/event_tracker.js

-// Copyright (c) 2011 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.
-
-/** @fileoverview EventTracker is a simple class that manages the addition and
- *  removal of DOM event listeners. In particular, it keeps track of all
- *  listeners that have been added and makes it easy to remove some or all of
- *  them without requiring all the information again. This is particularly
- *  handy when the listener is a generated function such as a lambda or the
- *  result of calling Function.bind.
- */
-
-// Use an anonymous function to enable strict mode just for this file (which
-// will be concatenated with other files when embedded in Chrome)
-var EventTracker = (function() {
-  'use strict';
-
-  /**
-   *  Create an EventTracker to track a set of events.
-   *  EventTracker instances are typically tied 1:1 with other objects or
-   *  DOM elements whose listeners should be removed when the object is disposed
-   *  or the corresponding elements are removed from the DOM.
-   *  @constructor
-   */
-  function EventTracker() {
-    /**
-     *  @type {Array.<EventTracker.Entry>}
-     *  @private
-     */
-    this.listeners_ = [];
-  }
-
-  /**
-   * The type of the internal tracking entry.
-   *  @typedef {{node: !Node,
-   *            eventType: string,
-   *            listener: Function,
-   *            capture: boolean}}
-   */
-  EventTracker.Entry;
-
-  EventTracker.prototype = {
-    /**
-     * Add an event listener - replacement for Node.addEventListener.
-     * @param {!Node} node The DOM node to add a listener to.
-     * @param {string} eventType The type of event to subscribe to.
-     * @param {Function} listener The listener to add.
-     * @param {boolean} capture Whether to invoke during the capture phase.
-     */
-    add: function(node, eventType, listener, capture) {
-      var h = {
-        node: node,
-        eventType: eventType,
-        listener: listener,
-        capture: capture
-      };
-      this.listeners_.push(h);
-      node.addEventListener(eventType, listener, capture);
-    },
-
-    /**
-     * Remove any specified event listeners added with this EventTracker.
-     * @param {!Node} node The DOM node to remove a listener from.
-     * @param {?string} eventType The type of event to remove.
-     */
-    remove: function(node, eventType) {
-      this.listeners_ = this.listeners_.filter(function(h) {
-        if (h.node == node && (!eventType || (h.eventType == eventType))) {
-          EventTracker.removeEventListener_(h);
-          return false;
-        }
-        return true;
-      });
-    },
-
-    /**
-     * Remove all event listeners added with this EventTracker.
-     */
-    removeAll: function() {
-      this.listeners_.forEach(EventTracker.removeEventListener_);
-      this.listeners_ = [];
-    }
-  };
-
-  /**
-   * Remove a single event listener given it's tracker entry.  It's up to the
-   * caller to ensure the entry is removed from listeners_.
-   * @param {EventTracker.Entry} h The entry describing the listener to remove.
-   * @private
-   */
-  EventTracker.removeEventListener_ = function(h) {
-    h.node.removeEventListener(h.eventType, h.listener, h.capture);
-  };
-
-  return EventTracker;
-})();
-