Correctly sets the security origin for the IME window.

chrome/test/data/extensions/api_test/input_ime_nonchromeos/background.js

 // Copyright 2016 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.
 
 chrome.test.runTests([
   function testActivate() {
     var focused = false;
     var activated = false;
     chrome.input.ime.onFocus.addListener(function(context) {
       if (context.type == 'none') {
@@ skipping 14 matching lines @@
         chrome.test.succeed();
     });
   },
   function testNormalCreateWindow() {
     var options = { windowType: 'normal' };
     chrome.input.ime.createWindow(options, function(win) {
       chrome.test.assertNoLastError()
       chrome.test.assertTrue(!!win);
       chrome.test.assertTrue(win instanceof Window);
       chrome.test.assertFalse(win.document.webkitHidden);
+      // Test for security origin.
+      // If security origin is not correctly set, there will be securtiy
+      // exceptions when accessing DOM or add event listeners.
+      win.addEventListener('unload', function() {});
       chrome.test.succeed();
     });
   },
   function testFollowCursorCreateWindow() {
     var options = { windowType: 'followCursor' };
     chrome.input.ime.createWindow(options, function(win) {
       chrome.test.assertNoLastError()
       chrome.test.assertTrue(!!win);
+      chrome.test.assertTrue(win instanceof Window);
       chrome.test.assertFalse(win.document.webkitHidden);
+      // test for security origin.
+      // If security origin is not correctly set, there will be securtiy
+      // exceptions when accessing DOM or add event listeners.
+      win.addEventListener('unload', function() {});
       chrome.test.succeed();
     });
   }
 ]);