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

chrome/common/extensions/api/experimental_system_info_storage.idl

Index: chrome/common/extensions/api/experimental_system_info_storage.idl
diff --git a/chrome/common/extensions/api/experimental_system_info_storage.idl b/chrome/common/extensions/api/experimental_system_info_storage.idl
index d6d5002dfcc6a38f0c91ee6b271da30cf570c318..85501180f328035203cb0cd354a453cdbf3cc6c1 100644
--- a/chrome/common/extensions/api/experimental_system_info_storage.idl
+++ b/chrome/common/extensions/api/experimental_system_info_storage.idl
@@ -14,18 +14,20 @@ namespace experimental.systemInfo.storage {
   };
 
   dictionary StorageUnitInfo {
-    // The unique id of the storage unit.
+    // The unique storage id. It is persistent between storage attachments.
     DOMString id;
+    // The mount path of the storage unit.
+    DOMString location;
     // The media type of the storage unit.
     StorageUnitType type;
-    // The total amount of the storage space, in bytes.
+    // The total amount of the storage space, in bytes, default value is 0.
     double capacity;
-    // The available amount of the storage space, in bytes.
+    // The available amount of the storage space, in bytes, default value is 0.
     double availableCapacity;
   };
 
-  dictionary StorageChangeInfo {
-    // The uniue id of the storage unit already changed.
+  dictionary StorageCapacityChangeInfo {
+    // The unique id of the storage unit already changed.
     DOMString id;
     // The new value of the available capacity.
     double availableCapacity;
@@ -65,7 +67,7 @@ namespace experimental.systemInfo.storage {
   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);
+    static void onAvailableCapacityChanged(StorageCapacityChangeInfo info);
 
     // Fired when a new removable storage is attached to the system.
     static void onAttached(StorageUnitInfo info);