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

chrome/browser/system_monitor/removable_device_notifications_window_win.h

Index: chrome/browser/system_monitor/removable_device_notifications_window_win.h
diff --git a/chrome/browser/system_monitor/removable_device_notifications_window_win.h b/chrome/browser/system_monitor/removable_device_notifications_window_win.h
index b05782677af63d7eaf2174182c47b9d159c37b4a..5584a13875b42cc8bfbd35017b4b49ba2ddba7cb 100644
--- a/chrome/browser/system_monitor/removable_device_notifications_window_win.h
+++ b/chrome/browser/system_monitor/removable_device_notifications_window_win.h
@@ -19,7 +19,8 @@ typedef LRESULT (*VolumeNameFunc)(LPCWSTR drive,
 namespace chrome {
 
 class RemovableDeviceNotificationsWindowWin
-    : public base::RefCountedThreadSafe<RemovableDeviceNotificationsWindowWin> {
+    : public base::RefCountedThreadSafe<RemovableDeviceNotificationsWindowWin>,
+      public base::SystemMonitor::StorageFreeSpaceDelegate {
  public:
   RemovableDeviceNotificationsWindowWin();
   // Only for use in unit tests.
@@ -54,6 +55,11 @@ class RemovableDeviceNotificationsWindowWin
       const FilePath::StringType& device_name,
       const FilePath& path);
 
+  // Overriden from SystemMonitor::StorageFreeSpaceDelegate.
+  virtual bool IsWatchingStorage(const FilePath& path) OVERRIDE;
+  virtual void StartWatchingStorage(const FilePath& path) OVERRIDE;
+  virtual void StopWatchingStorage(const FilePath& path) OVERRIDE;
+
   // The window class of |window_|.
   ATOM atom_;