This is UI side unreadable device support.

chrome/browser/extensions/extension_file_browser_private_api.h

 // Copyright (c) 2011 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_EXTENSION_FILE_BROWSER_PRIVATE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_FILE_BROWSER_PRIVATE_API_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 278 matching lines @@
   virtual bool RunImpl() OVERRIDE;
 
 // FileBrowserFunction overrides.
   virtual void GetLocalPathsResponseOnUIThread(const FilePathList& files,
                                                void* context) OVERRIDE;
 
  private:
   DECLARE_EXTENSION_FUNCTION_NAME("fileBrowserPrivate.formatDevice");
 };
 
+// Formats Device given its file path.

[tbarzic, 2011/08/25 02:03:44]

If you don't use this (and don't plan to), I think it's better not to add it...
It won't be a problem to add it later if needed..

[sidor, 2011/08/25 18:02:13]

Done.

+class FormatUnmountedDeviceFunction
+    : public SyncExtensionFunction {
+ public:
+  FormatUnmountedDeviceFunction();
+
+ protected:
+  virtual ~FormatUnmountedDeviceFunction();
+
+  virtual bool RunImpl() OVERRIDE;
+
+ private:
+  DECLARE_EXTENSION_FUNCTION_NAME("fileBrowserPrivate.formatUnmountedDevice");
+};
+
 // Retrieves devices meta-data. Expects volume's device path as an argument.
 class GetVolumeMetadataFunction
     : public SyncExtensionFunction {
  public:
   GetVolumeMetadataFunction();
 
  protected:
   virtual ~GetVolumeMetadataFunction();
 
   virtual bool RunImpl() OVERRIDE;
@@ skipping 15 matching lines @@
   virtual ~FileDialogStringsFunction() {}
 
   // SyncExtensionFunction overrides.
   virtual bool RunImpl() OVERRIDE;
 
  private:
   DECLARE_EXTENSION_FUNCTION_NAME("fileBrowserPrivate.getStrings");
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_FILE_BROWSER_PRIVATE_API_H_