[SystemInfo API] Rewrite storage info provider using storage monitor impl

chrome/common/extensions/api/experimental_system_info_storage.idl

 // 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.
 
 namespace experimental.systemInfo.storage {
 
   enum StorageUnitType {
     // The storage has fixed media, e.g. hard disk or SSD.
     fixed,
     // The storage is removable, e.g. USB flash drive.
     removable,
     // The storage type is unknown.
     unknown
   };
 
   dictionary StorageUnitInfo {
-    // The unique id of the storage unit.
+    // The unique storage id. It is persistent between storage attachments.

[vandebo (ex-Chrome), 2013/05/28 20:00:29]

This will take more work.

[Hongbo Min, 2013/05/29 01:05:38]

Do you mean using transient ID instead?

     DOMString id;
-    // The media type of the storage unit.
+    // Human readable storage unit name.
+    DOMString name;
+    // The mount path of the storage unit. 
+    DOMString location;
+    // Human readable vendor name for the storage unit. May be empty if not
+    // collected.
+    DOMString vendorName;
+    // Human readable model name for the storage unit. May be empty if not
+    // collected.
+    DOMString modelName;
+    // The type of storage device. The value is one of the constants defined
+    // for this type.
     StorageUnitType type;
     // The total amount of the storage space, in bytes.
     double capacity;
     // The available amount of the storage space, in bytes.
     double availableCapacity;
   };
 
   dictionary StorageChangeInfo {
     // The uniue id of the storage unit already changed.
     DOMString id;
+    // The old value of the available capacity.
+    double oldValue;
     // The new value of the available capacity.
-    double availableCapacity;
+    double newValue;
   };
 
   callback StorageInfoCallback = void (StorageUnitInfo[] info);
 
   interface Functions {
     // Get the storage information from the system. The argument passed to the
     // callback is an array of StorageUnitInfo objects.
     static void get(StorageInfoCallback callback);
   };
 
   interface Events {
     // Fired when the storage device available capacity is changed.
     // |info|: The changed information for the specified storage unit.
     static void onAvailableCapacityChanged(StorageChangeInfo info);
 
     // Fired when a new removable storage is attached to the system.
     static void onAttached(StorageUnitInfo info);
 
     // Fired when a removable storage is detached from the system.
     static void onDetached(DOMString id);
   };
  
 };