Add systeminfo.storage API implementation skeleton

chrome/common/extensions/api/experimental_systeminfo_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 {
+    // Unknow storage type
+    unknown,
+    // Hard disk
+    harddisk,
+    // USB Mass storage
+    usb,
+    // SD card
+    mmc
+  };
+
+  dictionary StorageUnitInfo {
+    // The unique id

[James Hawkins, 2012/08/09 15:47:34]

nit: Comments must end with a period, here and elsewhere.

[Hongbo Min, 2012/08/12 03:31:58]

Done.

+    DOMString id;
+    // 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 StorageInfo {
+    // The array of storage units connected to the system.
+    StorageUnitInfo[] units;
+  };
+
+  dictionary StorageUnitChangeInfo {
+    // The unique ID of storage unit on which the change is taken place.
+    DOMString id;
+    // The changed availableCapacity property
+    double availableCapacity;
+  };
+
+  callback StorageInfoCallback = void (StorageInfo info);
+  callback StorageUnitChangeCallback = void (StorageUnitChangeInfo unit);
+
+  interface Functions {
+    // Get the storage information in the system
+    static void get(StorageInfoCallback callback);
+  };
+
+  interface Events {
+    // Fired when the specified storage unit information is updated.
+    // |info|   : The changed information for the specified storage unit
+    static void onChanged(StorageUnitChangeInfo info);
+
+    // Fired when a new storage unit is added to the system,
+    // i.e. a new USB disk is plugged in.
+    // |unit| : The information of the new storage unit
+    static void onAdded(StorageUnitInfo unit);
+
+    // Fired when a storage unit is removed from the system
+    // i.e. a USB disk is unplugged
+    // |id| : The unique ID of storage unit already removed
+    static void onRemoved(DOMString id);
+  };
+};
+