Display active media players on chrome://media-internals.

chrome/browser/resources/media_internals/event_list.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.
+
+cr.define('media', function() {
+  'use strict';
+
+  /**
+   * This class holds a list of MediaLogEvents.
+   * It inherits from <li> and contains a tabular list of said events,
+   * the time at which they occurred, and their parameters.
+   */
+  var EventList = cr.ui.define('li');
+
+  EventList.prototype = {
+    __proto__: HTMLLIElement.prototype,
+    startTime_: null,
+
+    /**
+     * Decorate this list item as an EventList.
+     */
+    decorate: function() {
+      this.table_ = document.createElement('table');
+      var details = document.createElement('details');
+      var summary = media.makeElement('summary', 'Log:');
+      details.appendChild(summary);
+      details.appendChild(this.table_);
+      this.appendChild(details);
+
+      var hRow = document.createElement('tr');
+      hRow.appendChild(media.makeElement('th', 'Time:'));
+      hRow.appendChild(media.makeElement('th', 'Event:'));
+      hRow.appendChild(media.makeElement('th', 'Parameters:'));
+      var header = document.createElement('thead');
+      header.appendChild(hRow);
+      this.table_.appendChild(header);
+    },
+
+    /**
+     * Add an event to the list. It is stored as a new row in this.table_.
+     * @param {Object} event The MediaLogEvent that has occurred.
+     */
+    addEvent: function(event) {
+      var timeInMs = event.time * 1000;  // Work with milliseconds.
+      this.startTime_ = this.startTime_ || timeInMs;
+      timeInMs -= this.startTime_;
+
+      var row = document.createElement('tr');
+      row.appendChild(media.makeElement('td', timeInMs.toFixed(1)));
+      row.appendChild(media.makeElement('td', event.type));
+      var params = [];
+      for (var i = 0; i < event.params.length; ++i) {
+        params.push(i + ': ' + event.params[i]);
+      }
+
+      row.appendChild(media.makeElement('td', params.join(', ')));
+      this.table_.appendChild(row);
+    }
+  };
+
+  return {
+    EventList: EventList
+  };
+});