remoting/host: Fix cpplint warning of header guards.

remoting/host/disconnect_window.h

Index: remoting/host/disconnect_window.h
diff --git a/remoting/host/disconnect_window.h b/remoting/host/disconnect_window.h
index f55a90b83809a15a41aa72f84264d94f9ea49445..9fd071c4b2c3c5bf6b01196b9cadefc1d8890dc4 100644
--- a/remoting/host/disconnect_window.h
+++ b/remoting/host/disconnect_window.h
@@ -2,8 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef REMOTING_HOST_DISCONNECT_WINDOW_H
-#define REMOTING_HOST_DISCONNECT_WINDOW_H
+#ifndef REMOTING_HOST_DISCONNECT_WINDOW_H_
+#define REMOTING_HOST_DISCONNECT_WINDOW_H_
+#pragma once
 
 #include <string>
 
@@ -16,7 +17,6 @@ class ChromotingHost;
 
 class DisconnectWindow {
  public:
-
   enum {
     kMaximumConnectedNameWidthInPixels = 400
   };
@@ -39,6 +39,6 @@ class DisconnectWindow {
   static scoped_ptr<DisconnectWindow> Create();
 };
 
-}
+}  // namespace remoting
 
-#endif  // REMOTING_HOST_DISCONNECT_WINDOW_H
+#endif  // REMOTING_HOST_DISCONNECT_WINDOW_H_