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

chrome/browser/storage_monitor/storage_monitor_chromeos.h

Index: chrome/browser/storage_monitor/storage_monitor_chromeos.h
diff --git a/chrome/browser/storage_monitor/storage_monitor_chromeos.h b/chrome/browser/storage_monitor/storage_monitor_chromeos.h
index bd40f3e500936a67180a014192c184a3328c5b66..b7e0263d7f9f06a25fb10a463573b2f0edcd17cf 100644
--- a/chrome/browser/storage_monitor/storage_monitor_chromeos.h
+++ b/chrome/browser/storage_monitor/storage_monitor_chromeos.h
@@ -67,6 +67,8 @@ class StorageMonitorCros : public chrome::StorageMonitor,
       base::Callback<void(EjectStatus)> callback) OVERRIDE;
   virtual device::MediaTransferProtocolManager*
       media_transfer_protocol_manager() OVERRIDE;
+  virtual std::vector<chrome::StorageInfo>
+      GetAllAvailableStorages() const OVERRIDE;
 
  private:
   // Mapping of mount path to removable mass storage info.