exo: Produce an error if get_keyboard_device_configuration is called with a keyboard object that al…

components/exo/keyboard.h

 // Copyright 2015 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 COMPONENTS_EXO_KEYBOARD_H_
 #define COMPONENTS_EXO_KEYBOARD_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 15 matching lines @@
 // devices.
 class Keyboard : public ui::EventHandler,
                  public WMHelper::FocusObserver,
                  public WMHelper::InputDeviceEventObserver,
                  public WMHelper::MaximizeModeObserver,
                  public SurfaceObserver {
  public:
   explicit Keyboard(KeyboardDelegate* delegate);
   ~Keyboard() override;
 
+  bool HasDeviceConfigurationDelegate() const;
   void SetDeviceConfigurationDelegate(
       KeyboardDeviceConfigurationDelegate* delegate);
 
   // Overridden from ui::EventHandler:
   void OnKeyEvent(ui::KeyEvent* event) override;
 
   // Overridden WMHelper::FocusObserver:
   void OnWindowFocused(aura::Window* gained_focus,
                        aura::Window* lost_focus) override;
 
@@ skipping 27 matching lines @@
 
   // Current set of modifier flags.
   int modifier_flags_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(Keyboard);
 };
 
 }  // namespace exo
 
 #endif  // COMPONENTS_EXO_KEYBOARD_H_