Add error handler for license request.

media/test/data/eme_player_js/utils.js

 // Copyright 2014 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.
 
 // Utils provide logging functions and other JS functions commonly used by the
 // app and media players.
 var Utils = new function() {
   this.titleChanged = false;
 };
 
@@ skipping 208 matching lines @@
 
   function sendRequestAttempt() {
     requestAttemptCount++;
     if (requestAttemptCount == MAXIMUM_REQUEST_ATTEMPTS) {
       Utils.failTest('FAILED: Exceeded maximum license request attempts.');
       return;
     }
     var xmlhttp = new XMLHttpRequest();
     xmlhttp.responseType = responseType;
     xmlhttp.open(requestType, serverURL, true);
-
+    xmlhttp.onerror = function(e) {
+      Utils.failTest('FAILED: Unable to request license.');

[ddorwin, 2014/09/30 20:43:44]

How about:
'FAILED: License request XHR failed.'

That's more meaningful to the reader.

Is there something in |e|, even in some cases, that we can print to provide more
context?
Also, we could print the serverURL and maybe other values.

[sandersd (OOO until July 31), 2014/09/30 20:56:35]

Done.

The server URL is logged at the start of the attempt.

All the other values are empty, but I've added logging of statusText anyway.

+    };
     xmlhttp.onload = function(e) {
       if (this.status == 200) {
         if (onSuccessCallbackFn)
           onSuccessCallbackFn(this.response);
       } else {
         Utils.timeLog('Bad response status: ' + this.status);
         Utils.timeLog('Bad response: ' + this.response);
         Utils.timeLog('Retrying request if possible in ' +
                       REQUEST_RETRY_DELAY_MS + 'ms');
         setTimeout(sendRequestAttempt, REQUEST_RETRY_DELAY_MS);
@@ skipping 27 matching lines @@
   var time = Utils.getCurrentTimeString();
   // Log to document.
   Utils.documentLog(arguments[0], time);
   // Log to JS console.
   var logString = time + ' - ';
   for (var i = 0; i < arguments.length; i++) {
     logString += ' ' + arguments[i];
   }
   console.log(logString);
 };