Remove prefixed EME.

media/test/data/eme_player_js/file_io_test_player.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.
 
 // File IO test player is used to test File IO CDM functionality.
 function FileIOTestPlayer(video, testConfig) {
   this.video = video;
   this.testConfig = testConfig;
 }
 
 FileIOTestPlayer.prototype.init = function() {
   // Returns a promise.
   return PlayerUtils.initEMEPlayer(this);
 };
 
 FileIOTestPlayer.prototype.registerEventListeners = function() {
   // Returns a promise.
-  return PlayerUtils.registerEMEEventListeners(this).then(function(result) {
-    return PlayerUtils.registerPrefixedEMEEventListeners(this);
-  });
+  return PlayerUtils.registerEMEEventListeners(this);
 };
 
 handleMessage = function(message) {
   // The test result is either '0' or '1' appended to the header.
   var msg = Utils.convertToUint8Array(message.message);
   if (Utils.hasPrefix(msg, FILE_IO_TEST_RESULT_HEADER)) {
     if (msg.length != FILE_IO_TEST_RESULT_HEADER.length + 1) {
       Utils.failTest('Unexpected FileIOTest CDM message' + msg);
       return;
     }
     var result_index = FILE_IO_TEST_RESULT_HEADER.length;
     var success = String.fromCharCode(msg[result_index]) == 1;
     Utils.timeLog('CDM file IO test: ' + (success ? 'Success' : 'Fail'));
     if (success)
       Utils.setResultInTitle(FILE_IO_TEST_SUCCESS);
     else
       Utils.failTest('File IO CDM message fail status.');
   }
 };
 
-// Check message for prefixed API.
-FileIOTestPlayer.prototype.onWebkitKeyMessage = handleMessage;
-
-// Check message for unprefixed API.
 FileIOTestPlayer.prototype.onMessage = handleMessage;