UI refresh of Advanced Font Settings Extension

chrome/common/extensions/docs/examples/api/fontSettings/js/cr/event_target.js

-// Copyright (c) 2010 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 This contains an implementation of the EventTarget interface
- * as defined by DOM Level 2 Events.
- */
-
-cr.define('cr', function() {
-
-  /**
-   * Creates a new EventTarget. This class implements the DOM level 2
-   * EventTarget interface and can be used wherever those are used.
-   * @constructor
-   */
-  function EventTarget() {
-  }
-
-  EventTarget.prototype = {
-
-    /**
-     * Adds an event listener to the target.
-     * @param {string} type The name of the event.
-     * @param {!Function|{handleEvent:Function}} handler The handler for the
-     *     event. This is called when the event is dispatched.
-     */
-    addEventListener: function(type, handler) {
-      if (!this.listeners_)
-        this.listeners_ = Object.create(null);
-      if (!(type in this.listeners_)) {
-        this.listeners_[type] = [handler];
-      } else {
-        var handlers = this.listeners_[type];
-        if (handlers.indexOf(handler) < 0)
-          handlers.push(handler);
-      }
-    },
-
-    /**
-     * Removes an event listener from the target.
-     * @param {string} type The name of the event.
-     * @param {!Function|{handleEvent:Function}} handler The handler for the
-     *     event.
-     */
-    removeEventListener: function(type, handler) {
-      if (!this.listeners_)
-        return;
-      if (type in this.listeners_) {
-        var handlers = this.listeners_[type];
-        var index = handlers.indexOf(handler);
-        if (index >= 0) {
-          // Clean up if this was the last listener.
-          if (handlers.length == 1)
-            delete this.listeners_[type];
-          else
-            handlers.splice(index, 1);
-        }
-      }
-    },
-
-    /**
-     * Dispatches an event and calls all the listeners that are listening to
-     * the type of the event.
-     * @param {!cr.event.Event} event The event to dispatch.
-     * @return {boolean} Whether the default action was prevented. If someone
-     *     calls preventDefault on the event object then this returns false.
-     */
-    dispatchEvent: function(event) {
-      if (!this.listeners_)
-        return true;
-
-      // Since we are using DOM Event objects we need to override some of the
-      // properties and methods so that we can emulate this correctly.
-      var self = this;
-      event.__defineGetter__('target', function() {
-        return self;
-      });
-      event.preventDefault = function() {
-        this.returnValue = false;
-      };
-
-      var type = event.type;
-      var prevented = 0;
-      if (type in this.listeners_) {
-        // Clone to prevent removal during dispatch
-        var handlers = this.listeners_[type].concat();
-        for (var i = 0, handler; handler = handlers[i]; i++) {
-          if (handler.handleEvent)
-            prevented |= handler.handleEvent.call(handler, event) === false;
-          else
-            prevented |= handler.call(this, event) === false;
-        }
-      }
-
-      return !prevented && event.returnValue;
-    }
-  };
-
-  // Export
-  return {
-    EventTarget: EventTarget
-  };
-});