Add title property to chrome.printerProvider pritn job

extensions/test/data/api_test/printer_provider/request_print/test.js

 // Copyright 2015 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.
 
 // Reads a blob content.
 // @param {!Blob} blob The blob to read.
 // @param {function(?string)} callback Called with the read blob content.
 //     the content will be null on error.
 function readBlob(blob, callback) {
   var reader = new FileReader();
@@ skipping 46 matching lines @@
         case 'INVALID_DATA':
           wrapPrintCallback(callback, test);
           break;
         case 'OK':
           readBlob(job.document, function(content) {
             wrapPrintCallback(callback, !!content ? 'OK' : 'INVALID_DATA');
 
             if (content)
               chrome.test.assertEq('bytes', content);
 
+            chrome.test.assertEq('Print job', job.title);
+
             chrome.test.succeed();
           });
 
           // Test will end asynchronously.
           return;
         default:
           callback('FAILED');
           chrome.test.fail('Invalid input');
           return;
       }
 
       chrome.test.succeed();
     });
 
     chrome.test.sendMessage('ready');
   }]);
 });