kFileSystemTypeIsolated should be only used in the URL exposed to renderer

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 {
 
 enum FileSystemType {
   // Indicates uninitialized or invalid filesystem type.
   kFileSystemTypeUnknown = -1,
 
+  // ------------------------------------------------------------------------
+  // Public FileSystem types, that are embedded in filesystem: URL and exposed
+  // to WebKit/renderer. Both Chrome and WebKit know how to handle these types.
+
   // Following two types are for TEMPORARY or PERSISTENT filesystems that
   // can be used by webapps via standard app-facing API
   // as defined in File API: Directories and System.
   // http://www.w3.org/TR/file-system-api/#temporary-vs.-persistent-storage
   // They are sandboxed filesystems; all the files in the filesystems are
   // placed under the profile directory with path obfuscation and quota
   // enforcement.
   kFileSystemTypeTemporary = WebKit::WebFileSystem::TypeTemporary,
   kFileSystemTypePersistent = WebKit::WebFileSystem::TypePersistent,
 
   // 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,
 
+  // ------------------------------------------------------------------------
+  // Private FileSystem types, that should not appear in filesystem: URL as
+  // WebKit has no idea how to handle those types.
+  //
+  // One can register (mount) a new file system with a private file system type
+  // using IsolatedContext.  Files in such file systems can be accessed via
+  // either Isolated or External public file system types (depending on
+  // how the file system is registered).
+  // See the comments for IsolatedContext and/or FileSystemURL for more details.
+
   // Should be used only for testing.
   kFileSystemTypeTest = 100,
 
-  // Following file system types are internal and they are not exposed to
-  // WebKit, but are accessible via IsolatedContext.
-
-  // Indicates a transient, isolated file system for a native local path.
-  // TODO(kinuko): Rename all kFileSystemTypeIsolated used as internal type
-  // with this one.
+  // Indicates a local filesystem where we can access files using native
+  // local path.
   kFileSystemTypeNativeLocal,
 
   // Indicates a transient, isolated file system for dragged files (which could
   // contain multiple dragged paths in the virtual root).
   kFileSystemTypeDragged,
 
   // Indicates media filesystem which we can access with same manner to
   // regular filesystem.
   kFileSystemTypeNativeMedia,
 
   // Indicates media filesystem to which we need special protocol to access,
   // such as MTP or PTP.
   kFileSystemTypeDeviceMedia,
 
   // Indicates a Drive filesystem which provides access to Google Drive.
   kFileSystemTypeDrive,
 };
 
-enum FileSystemMountType {
-  kFileSystemMountTypeUnknown = -1,
-
-  // For kFileSystemTypeIsolated file systems. URLs for this type of
-  // file system is cracked via IsolatedContext.
-  kFileSystemMountTypeIsolated = kFileSystemTypeIsolated,
-
-  // For kFileSystemTypeIsolated file systems. URLs for this type of
-  // file system is cracked via IsolatedContext.
-  kFileSystemMountTypeExternal = kFileSystemTypeExternal,
-};
-
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_TYPES_H_