Handle no volume in chrome://media-internals

chrome/browser/resources/media_internals/media_internals.js

Index: chrome/browser/resources/media_internals/media_internals.js
diff --git a/chrome/browser/resources/media_internals/media_internals.js b/chrome/browser/resources/media_internals/media_internals.js
index 7218c06b8d8596c554c6f6bdf9ee337043d65822..09821c81f048f3b04d5c222c25244d5ac164db2d 100644
--- a/chrome/browser/resources/media_internals/media_internals.js
+++ b/chrome/browser/resources/media_internals/media_internals.js
@@ -41,8 +41,8 @@ cr.define('media', function() {
    * Initialize variables and ask MediaInternals for all its data.
    */
   function initialize() {
-    audioStreamDiv = document.getElementById('audio-streams');
-    cacheDiv = document.getElementById('cache-entries');
+    audioStreamDiv = $('audio-streams');
+    cacheDiv = $('cache-entries');
 
     // Get information about all currently active media.
     chrome.send('getEverything');
@@ -66,14 +66,16 @@ cr.define('media', function() {
 
       out.textContent += 'Audio stream ' + stream.id.split('.')[1];
       out.textContent += ' is ' + (stream.playing ? 'playing' : 'paused');
-      out.textContent += ' at ' + (stream.volume * 100).toFixed(0);
-      out.textContent += '% volume.';
+      if (typeof stream.volume != 'undefined') {
+        out.textContent += ' at ' + (stream.volume * 100).toFixed(0);
+        out.textContent += '% volume.';
+      }
       return out;
     }
 
     var out = document.createElement('ul');
     audioStreams.map(printStream).forEach(function(s) {
-      out.appendChild(s)
+      out.appendChild(s);
     });
 
     audioStreamDiv.textContent = '';
@@ -147,7 +149,7 @@ cr.define('media', function() {
   function onRendererTerminated(renderer) {
     for (var key in mediaPlayers) {
       if (mediaPlayers[key].renderer == renderer) {
-        document.getElementById('media-players').removeChild(mediaPlayers[key]);
+        $('media-players').removeChild(mediaPlayers[key]);
         delete mediaPlayers[key];
         break;
       }