Add more FS types and introduce type field into IsolatedContext

webkit/fileapi/file_system_types.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 WEBKIT_FILEAPI_FILE_SYSTEM_TYPES_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_TYPES_H_
 
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebFileSystem.h"
 
 namespace fileapi {
@@ skipping 15 matching lines @@
   // Indicates non-sandboxed isolated filesystem.
   kFileSystemTypeIsolated = WebKit::WebFileSystem::TypeIsolated,
 
   // Indicates non-sandboxed filesystem where files are placed outside the
   // profile directory (thus called 'external' filesystem).
   // This filesystem is used only by Chrome OS as of writing.
   kFileSystemTypeExternal = WebKit::WebFileSystem::TypeExternal,
 
   // Should be used only for testing.
   kFileSystemTypeTest = 100,
+
+  // Internal filesystem types, which are not exposed to WebKit but are
+  // accessible via Isolated file system.
+  kFileSystemTypeDragged,
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_TYPES_H_