Display active audio streams on chrome://media-internals.

chrome/browser/resources/media_internals/media_internals.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() {
+
+  // Stores information on open audio streams, referenced by id.
+  var audioStreams = new media.ItemStore;
+  // The <div> on the page in which to display audio stream data.
+  var audioStreamDiv;
+
+  /**
+   * Initialize variables and ask MediaInternals for all its data.
+   */
+  initialize = function() {
+    audioStreamDiv = document.getElementById('audio-streams');
+    // Get information about all currently active media.
+    chrome.send('getEverything');
+  };
+
+  /**
+   * Write the set of audio streams to the DOM.
+   */
+  printAudioStreams = function() {
+
+    /**
+     * Render a single stream as a <li>.
+     * @param {Object} stream The stream to render.
+     * @return {HTMLElement} A <li> containing the stream information.
+     */
+    printStream = function(stream) {
+      var out = document.createElement('li');
+      out.id = stream.id;
+      out.className = 'audio-stream';
+      out.setAttribute('status', stream.status);
+
+      out.innerHTML += 'Audio stream ' + stream.id.split('.')[1];
+      out.innerHTML += ' is ' + (stream.playing ? 'playing' : 'paused');
+      out.innerHTML += ' at ' + Math.round(stream.volume * 100) + '% volume.';
+      return out;
+    };
+
+    var out = document.createElement('ul');
+    audioStreams.map(printStream).forEach(function(s) {
+      out.appendChild(s)
+    });
+
+    audioStreamDiv.textContent = '';
+    audioStreamDiv.appendChild(out);
+  };
+
+  /**
+   * Receiving data for an audio stream.
+   * Add it to audioStreams and update the page.
+   * @param {Object} stream JSON representation of an audio stream.
+   */
+  addAudioStream = function(stream) {
+    audioStreams.addItem(stream);
+    printAudioStreams();
+  };
+
+  /**
+   * Receiving all data.
+   * Add it all to the appropriate stores and update the page.
+   * @param {Object} stuff JSON containing lists of data.
+   * @param {Object} stuff.audio_streams A dictionary of audio streams.
+   */
+  onReceiveEverything = function(stuff) {
+    audioStreams.addItems(stuff.audio_streams);
+    printAudioStreams();
+  };
+
+  /**
+   * Removing an item from the appropriate store.
+   * @param {string} id The id of the item to be removed, in the format
+   *    "item_type.identifying_info".
+   */
+  onItemDeleted = function(id) {
+    var type = id.split('.')[0];
+    switch (type) {
+    case 'audio_streams':
+      audioStreams.removeItem(id);
+      printAudioStreams();
+      break;
+    }
+  };
+
+  return {
+    initialize: initialize,
+    addAudioStream: addAudioStream,
+    onReceiveEverything: onReceiveEverything,
+    onItemDeleted: onItemDeleted,
+  };
+});
+
+/**
+ * Initialize everything once we have access to the DOM.
+ */
+window.onload = function() {
+  media.initialize();
+};