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

chrome/browser/resources/media_internals/media_player.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 inherits from <li> and is designed to store and display
+   * information about an open media player.
+   */
+  var MediaPlayer = cr.ui.define('li');
+
+  MediaPlayer.prototype = {
+    __proto__: HTMLLIElement.prototype,
+    renderer: null,
+    id: null,
+
+    /**
+     * Decorate this <li> as a MediaPlayer.
+     */
+    decorate: function() {
+      this.properties = {};
+
+      this.details_ = document.createElement('details');
+      this.summary_ = document.createElement('summary');
+      this.details_.appendChild(this.summary_);
+
+      this.propertyTable_ = document.createElement('table');
+      this.events_ = new media.EventList;
+      this.metrics_ = new media.Metrics;
+
+      var properties = media.createDetailsLi();
+      properties.summary.textContent = 'Properties:';
+      properties.details.appendChild(this.propertyTable_);
+
+      var ul = document.createElement('ul');
+      ul.appendChild(properties);
+      ul.appendChild(this.metrics_);
+      ul.appendChild(this.events_);
+      this.details_.appendChild(ul);
+
+      this.appendChild(this.details_);
+      document.getElementById('media-players').appendChild(this);
+    },
+
+    /**
+     * Record an event and update statistics etc.
+     * @param {Object} event The event that occurred.
+     */
+    addEvent: function(event) {
+      for (var key in event.params) {
+        this.properties[key] = event.params[key];
+      }
+
+      if (event.type == 'BUFFERED_EXTENTS_CHANGED')
+        return;
+      this.events_.addEvent(event);
+      this.metrics_.addEvent(event);
+    },
+
+    /**
+     * Update the summary line and properties table and redraw the canvas.
+     * @return {HTMLElement} A <li> representing this MediaPlayer.
+     */
+    redraw: function() {
+      media.appendDictionaryToTable(this.properties, this.propertyTable_);
+
+      this.setAttribute('status', this.properties.state);
+      this.summary_.textContent = '';
+      this.summary_.appendChild(document.createTextNode(
+            this.id + ' (' + this.properties.url + '):'));
+      this.summary_.appendChild(document.createElement('br'));
+
+      // Don't bother drawing anything if we don't know the total size.
+      var size = this.properties.total_bytes;
+      if (!size) {
+        return;
+      }
+
+      var bufferedDiv = document.createElement('div');
+      bufferedDiv.className = 'buffered';
+      this.summary_.appendChild(bufferedDiv);
+
+      function addEntry(label, canvas) {
+        var labelDiv = document.createElement('div');
+        labelDiv.textContent = label;
+        var canvasDiv = document.createElement('div');
+        canvasDiv.appendChild(canvas);
+        var entryDiv = document.createElement('div');
+        entryDiv.appendChild(labelDiv);
+        entryDiv.appendChild(canvasDiv);
+        bufferedDiv.appendChild(entryDiv);
+      }
+
+      // Draw the state of BufferedResourceLoader.
+      var canvas = document.createElement('canvas');
+      canvas.width = media.BAR_WIDTH;
+      canvas.height = media.BAR_HEIGHT;
+
+      var context = canvas.getContext('2d');
+      context.fillStyle = '#aaa';
+      context.fillRect(0, 0, canvas.width, canvas.height);
+
+      var left = this.properties.buffer_start / size * canvas.width;
+      var middle = this.properties.buffer_current / size * canvas.width;
+      var right = this.properties.buffer_end / size * canvas.width;
+      context.fillStyle = '#a0a';
+      context.fillRect(left, 0, middle - left, canvas.height);
+      context.fillStyle = '#aa0';
+      context.fillRect(middle, 0, right - middle, canvas.height);
+      addEntry('Buffered', canvas);
+
+      // Only show cached file information if we have something.
+      var cacheEntry = media.cacheEntriesByKey[this.properties.url];
+      if (!cacheEntry) {
+        return;
+      }
+
+      // Draw cache reads.
+      canvas = document.createElement('canvas');
+      canvas.width = media.BAR_WIDTH;
+      canvas.height = media.BAR_HEIGHT;
+      cacheEntry.drawCacheReadsToCanvas(canvas);
+      addEntry('Cache Reads', canvas);
+
+      // Draw cache writes.
+      canvas = document.createElement('canvas');
+      canvas.width = media.BAR_WIDTH;
+      canvas.height = media.BAR_HEIGHT;
+      cacheEntry.drawCacheWritesToCanvas(canvas);
+      addEntry('Cache Writes', canvas);
+    },
+  };
+
+  return {
+    MediaPlayer: MediaPlayer
+  };
+});