Add extension permissions for Media Gallery API.

chrome/test/data/extensions/api_test/media_gallery/read_permission/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)) {
     expectedFileSystems = 0;
   }
   chrome.test.assertEq(expectedFileSystems, results.length);
-};
-var nullCallback = function(result) {
-  chrome.test.assertEq(null, result);
+  // TODO(vandebo) Test that we can read from the FS.
 };
 
 function runTests(tests) {
-  chrome.test.getConfig(function(config) {
-    operatingSystem = config.osName;
-    chrome.test.runTests(tests);
-  });
+  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()
-  },
-
-  function assembleMediaFile() {
-    mediaGalleries.assembleMediaFile(
-        {}, {}, chrome.test.callbackPass(nullCallback));
-  },
 ]);