Extend the capability of SystemMonitor to support watching storage free space change

chrome/browser/system_monitor/media_device_notifications_window_win.cc

 // 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.
 
 #include "chrome/browser/system_monitor/media_device_notifications_window_win.h"
 
 #include <windows.h>
 #include <dbt.h>
 
 #include <string>
@@ skipping 141 matching lines @@
     const std::string& id,
     const FilePath::StringType& device_name,
     const FilePath& path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   SystemMonitor::Get()->ProcessRemovableStorageAttached(id,
                                                         device_name,
                                                         path.value());
 }
 
+bool MediaDeviceNotificationsWindowWin::StartWatchingStorage(
+    const FilePath::StringType& path) {
+  return false;
+}
+
+bool MediaDeviceNotificationsWindowWin::StopWatchingStorage(
+    const FilePath::StringType& path) {
+  return false;
+}
+
+
 LRESULT CALLBACK MediaDeviceNotificationsWindowWin::WndProc(
     HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
   switch (message) {
     case WM_DEVICECHANGE:
       return OnDeviceChange(static_cast<UINT>(wparam),
                             static_cast<DWORD>(lparam));
     default:
       break;
   }
 
   return ::DefWindowProc(hwnd, message, wparam, lparam);
 }
 
 // static
 LRESULT CALLBACK MediaDeviceNotificationsWindowWin::WndProcThunk(
     HWND hwnd,
     UINT message,
     WPARAM wparam,
     LPARAM lparam) {
   MediaDeviceNotificationsWindowWin* msg_wnd =
       reinterpret_cast<MediaDeviceNotificationsWindowWin*>(
           GetWindowLongPtr(hwnd, GWLP_USERDATA));
   if (msg_wnd)
     return msg_wnd->WndProc(hwnd, message, wparam, lparam);
   return ::DefWindowProc(hwnd, message, wparam, lparam);
 }
 
 }  // namespace chrome