Allow to create read only testing volumes.

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

 // Copyright (c) 2013 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.
 
 // Browser test for basic Chrome OS file manager functionality:
 //  - The file list is updated when a file is added externally to the Downloads
 //    folder.
 //  - Selecting a file and copy-pasting it with the keyboard copies the file.
 //  - Selecting a file and pressing delete deletes it.
 
@@ skipping 315 matching lines @@
     mount_points->RevokeFileSystem(name());
     const bool result =
         mount_points->RegisterFileSystem(name(),
                                          storage::kFileSystemTypeNativeLocal,
                                          storage::FileSystemMountOption(),
                                          root_path());
     if (!result)
       return false;
 
     VolumeManager::Get(profile)->AddVolumeInfoForTesting(
-        root_path(), volume_type_, device_type_);
+        root_path(), volume_type_, device_type_, false /* read_only */);
     return true;
   }
 
  private:
   const VolumeType volume_type_;
   const chromeos::DeviceType device_type_;
 };
 
 // The drive volume class for test.
 // This class provides the operations for a test volume that simulates Google
@@ skipping 1112 matching lines @@
   StartTest();
 }
 
 IN_PROC_BROWSER_TEST_F(VideoPlayerBrowserTest, OpenSingleVideoOnDrive) {
   set_test_case_name("openSingleVideoOnDrive");
   StartTest();
 }
 
 }  // namespace
 }  // namespace file_manager