This is UI side unreadable device support.

chrome/browser/chromeos/cros/mount_library.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_CHROMEOS_CROS_MOUNT_LIBRARY_H_
 #define CHROME_BROWSER_CHROMEOS_CROS_MOUNT_LIBRARY_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 117 matching lines @@
     bool has_media_;
     bool on_boot_device_;
   };
   typedef std::map<std::string, Disk*> DiskMap;
   typedef std::map<std::string, std::string> PathMap;
 
   struct MountPointInfo {
     std::string source_path;
     std::string mount_path;
     MountType mount_type;
+    std::string special_data;
 
-    MountPointInfo(const char* source, const char* mount, const MountType type)
+    MountPointInfo(const char* source, const char* mount, const MountType type,
+        const char* special)

[tbarzic, 2011/08/24 03:59:44]

special data seems a bit vague.. maybe something like format_status, or
device_status..
Also, I'd rather make this enum, or even bool value  (can_be_formatted) if you
decide to go with unified error message (see comment in file_manager.js).

[sidor, 2011/08/24 04:26:06]

So the idea is that there are some special condition related to the mount info.
That's why I created that field. In the future there might be more special
conditions. Making it enum is not a bad idea. Also if you think there's better
name for that field I am open to any suggestions.

         : source_path(source ? source : ""),
           mount_path(mount ? mount : ""),
-          mount_type(type) {
+          mount_type(type),
+          special_data(special ? special : "") {
     }
   };
 
   // MountPointMap key is mount_path.
   typedef std::map<std::string, MountPointInfo> MountPointMap;
 
   typedef void(*UnmountDeviceRecursiveCallbackType)(void*, bool);
 
   class Observer {
    public:
     virtual ~Observer() {}
     // Async API events.
     virtual void DiskChanged(MountLibraryEventType event,
                              const Disk* disk) = 0;
     virtual void DeviceChanged(MountLibraryEventType event,
-                               const std::string& device_path ) = 0;
+                               const std::string& device_path) = 0;
     virtual void MountCompleted(MountEvent event_type,
                                 MountError error_code,
                                 const MountPointInfo& mount_info) = 0;
   };
 
   virtual ~MountLibrary() {}
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
   virtual const DiskMap& disks() const = 0;
   virtual const MountPointMap& mount_points() const = 0;
@@ skipping 25 matching lines @@
   virtual void SetLibcrosProxy(MountLibcrosProxy* proxy) {}
 
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via CrosLibrary::Get().
   static MountLibrary* GetImpl(bool stub);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_CROS_MOUNT_LIBRARY_H_