Make isolated file system works for a device root (e.g. X:\\)

chrome/browser/extensions/api/app/app_api.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_APP_APP_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_APP_APP_API_H_
 #pragma once
 
 #include "chrome/browser/extensions/extension_function.h"
 
@@ skipping 46 matching lines @@
   // }
 
   // launchData.intent.data and launchData.intent.postResults are created in a
   // custom dispatch event in javascript. The FileEntry is created from
   // |file_system_id| and |base_name|.
   static void DispatchOnLaunchedEventWithFileEntry(
       Profile* profile,
       const Extension* extension,
       const string16& action,
       const std::string& file_system_id,
-      const FilePath& base_name);
+      const std::string& base_name);
 
   // Dispatches the onLaunched event to the app implemented by |extension|
   // running in |profile|. The event parameter launchData will have a field
   // called intent, populated by |web_intent_data|.
   static void DispatchOnLaunchedEventWithWebIntent(
       Profile* profile,
       const Extension* extension,
       const webkit_glue::WebIntentData web_intent_data);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_APP_APP_API_H_