Add notification for media changed, and notify volume mount watcher when it occurs.

components/storage_monitor/storage_monitor_win.h

Index: components/storage_monitor/storage_monitor_win.h
diff --git a/components/storage_monitor/storage_monitor_win.h b/components/storage_monitor/storage_monitor_win.h
index f59b3c3a9f16478fb2e7218816e2a3a339250fcc..537f0e5feb401436a3a32e960c705c084ee9c79a 100644
--- a/components/storage_monitor/storage_monitor_win.h
+++ b/components/storage_monitor/storage_monitor_win.h
@@ -50,6 +50,8 @@ class StorageMonitorWin : public StorageMonitor {
   class PortableDeviceNotifications;
   friend class TestStorageMonitorWin;
 
+  void MediaChangeNotificationRegister();
+
   // Gets the removable storage information given a |device_path|. On success,
   // returns true and fills in |info|.
   bool GetDeviceInfo(const base::FilePath& device_path,
@@ -62,6 +64,7 @@ class StorageMonitorWin : public StorageMonitor {
                            LPARAM lparam);
 
   void OnDeviceChange(UINT event_type, LPARAM data);
+  void OnMediaChange(WPARAM wparam, LPARAM lparam);
 
   // The window class of |window_|.
   ATOM window_class_;