Set the file name of the webrtc-internals dump "webrtc_internals_dump.txt".

content/browser/resources/media/dump_creator.js

 // Copyright (c) 2013 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.
 
 
 /**
  * Provides the UI for dump creation.
  */
 var DumpCreator = (function() {
   /**
@@ skipping 68 matching lines @@
     onDownloadData_: function() {
       var dump_object =
       {
         'getUserMedia': userMediaRequests,
         'PeerConnections': peerConnectionDataStore,
       };
       var textBlob = new Blob([JSON.stringify(dump_object, null, ' ')],
                               {type: 'octet/stream'});
       var URL = window.URL.createObjectURL(textBlob);
 
-      this.root_.getElementsByTagName('a')[0].href = URL;
+      var anchor = this.root_.getElementsByTagName('a')[0];
+      anchor.href = URL;
+      anchor.download = 'webrtc_internals_dump.txt';
       // The default action of the anchor will download the URL.
     },
 
     /**
      * Handles the event of toggling the AEC recording state.
      *
      * @private
      */
     onAecRecordingChanged_: function() {
       var enabled = this.root_.getElementsByTagName('input')[0].checked;
       if (enabled) {
         chrome.send('enableAecRecording');
       } else {
         chrome.send('disableAecRecording');
       }
     },
   };
   return DumpCreator;
 })();