[fsp] Let extensions decide about the file system id.

chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc

 // Copyright 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.
 
 #include "chrome/browser/chromeos/extensions/file_manager/private_api_mount.h"
 
 #include <string>
 
 #include "base/format_macros.h"
 #include "chrome/browser/chromeos/drive/file_system_interface.h"
@@ skipping 112 matching lines @@
           volume_info.mount_path.value(),
           chromeos::UNMOUNT_OPTIONS_NONE,
           DiskMountManager::UnmountPathCallback());
       break;
     }
     case file_manager::VOLUME_TYPE_PROVIDED: {
       chromeos::file_system_provider::Service* service =
           chromeos::file_system_provider::Service::Get(GetProfile());
       DCHECK(service);
       // TODO(mtomasz): Pass a more detailed error than just a bool.
-      if (!service->RequestUnmount(volume_info.file_system_id))
+      if (!service->RequestUnmount(volume_info.extension_id,
+                                   volume_info.file_system_id)) {
         return false;
+      }
       break;
     }
     default:
       // Requested unmounting a device which is not unmountable.
       return false;
   }
 
   SendResponse(true);
   return true;
 }
@@ skipping 26 matching lines @@
                 result.size());
   }
 
   results_ =
       file_browser_private::GetVolumeMetadataList::Results::Create(result);
   SendResponse(true);
   return true;
 }
 
 }  // namespace extensions