switch mediaGalleries to .idl api definition

chrome/test/data/extensions/api_test/media_galleries/test.js

 // Copyright (c) 2012 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.
 
 var mediaGalleries = chrome.experimental.mediaGalleries;
 var mediaFileSystemsListCallback = function(results) {
   // There should be a "Pictures" directory on all desktop platforms.
   var expectedFileSystems = 1;
   // But not on Android and ChromeOS.
   if (/Android/.test(navigator.userAgent) || /CrOS/.test(navigator.userAgent)) {
@@ skipping 11 matching lines @@
     chrome.test.runTests(tests);
   });
 }
 
 chrome.test.runTests([
   function getGalleries() {
     mediaGalleries.getMediaFileSystems(
         chrome.test.callbackPass(mediaFileSystemsListCallback));
   },
 
-  function openMediaGalleryManager() {
-    // Just confirm that the function exists.
-    chrome.test.assertTrue(mediaGalleries.openMediaGalleryManager !== null);
-    chrome.test.succeed()
-  },
-
   function extractEmbeddedThumbnails() {
     var result = mediaGalleries.extractEmbeddedThumbnails({});
     chrome.test.assertEq(null, result);
-    chrome.test.succeed()
+    chrome.test.succeed();
   },
 
   function assembleMediaFile() {
     mediaGalleries.assembleMediaFile(
-        {}, {}, chrome.test.callbackPass(nullCallback));
+        new Blob, {},
+        chrome.test.callbackPass(nullCallback));
   },
 ]);