Keep track of the list of currently mounted volumes in C++-side VolumeManager.

chrome/test/data/extensions/api_test/file_browser/mount_test/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.
 
 // These have to be sync'd with file_browser_private_apitest.cc
 var expectedVolume1 = {
   volumeId: 'removable:mount_path1',
   mountPath: '/removable/mount_path1',
   sourcePath: 'device_path1',
   volumeType: 'removable',
@@ skipping 52 matching lines @@
   volumeId: 'archive:archive_mount_path',
   mountPath: '/archive/archive_mount_path',
   sourcePath: 'archive_path',
   volumeType: 'archive',
   isReadOnly: true,
   profile: {profileId: "", displayName: "", isCurrentProfile: true}
 };
 
 // List of expected mount points.
 // NOTE: this has to be synced with values in file_browser_private_apitest.cc
-//       and values sorted by mountPath.
+//       and values sorted by volumeId.
 var expectedVolumeList = [
+  expectedArchiveVolume,
+  expectedDownloadsVolume,
   expectedDriveVolume,
-  expectedDownloadsVolume,
-  expectedArchiveVolume,
   expectedVolume1,
   expectedVolume2,
   expectedVolume3,
 ];
 
 function validateObject(received, expected, name) {
   for (var key in expected) {
     if (expected[key] instanceof RegExp) {
       if (!expected[key].test(received[key])) {
         console.warn('Expected "' + key + '" ' + name + ' property to match: ' +
@@ skipping 31 matching lines @@
     chrome.fileBrowserPrivate.removeMount('archive:archive_mount_path');
 
     // We actually check this one on C++ side. If MountLibrary.RemoveMount
     // doesn't get called, test will fail.
     chrome.test.succeed();
   },
 
   function getVolumeMetadataList() {
     chrome.fileBrowserPrivate.getVolumeMetadataList(
         chrome.test.callbackPass(function(result) {
-          chrome.test.assertEq(result.length, expectedVolumeList.length,
+          chrome.test.assertEq(expectedVolumeList.length, result.length,
               'getMountPoints returned wrong number of mount points.');
           for (var i = 0; i < expectedVolumeList.length; i++) {
             chrome.test.assertTrue(
                 validateObject(
                     result[i], expectedVolumeList[i], 'volumeMetadata'),
                 'getMountPoints result[' + i + '] not as expected');
           }
     }));
   }
 ]);