Add proxy settings to network control at upper row of controls at login screen.

chrome/browser/chromeos/status/status_area_host.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_HOST_H_
 #define CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_HOST_H_
 #pragma once
 
 #include "gfx/native_widget_types.h"
 
@@ skipping 15 matching lines @@
 
   // Returns native window hosting the status area.
   virtual gfx::NativeWindow GetNativeWindow() const = 0;
 
   // Indicates if options dialog related to the button specified should be
   // shown.
   virtual bool ShouldOpenButtonOptions(
       const views::View* button_view) const = 0;
 
   // Opens options dialog related to the button specified.
-  virtual void OpenButtonOptions(const views::View* button_view) const = 0;
+  virtual void OpenButtonOptions(const views::View* button_view) = 0;
 
   // Executes browser command.
   virtual void ExecuteBrowserCommand(int id) const = 0;
 
   // True if status area hosted in browser. Otherwise it's OOBE/login state.
   virtual bool IsBrowserMode() const = 0;
 
   // True if status area hosted in screen locker.
   virtual bool IsScreenLockerMode() const = 0;
 
  protected:
   virtual ~StatusAreaHost() {}
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_HOST_H_