text: // Copyright (c) 2012 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 ASH_SYSTEM_BRIGHTNESS_BRIGHTNESS_CONTROL_DELEGATE_H_
  #define ASH_SYSTEM_BRIGHTNESS_BRIGHTNESS_CONTROL_DELEGATE_H_
  #pragma once
  
  #include "base/callback.h"
  
  namespace ui {
  class Accelerator;
  }  // namespace ui
  
  namespace ash {
  
  // Delegate for controlling the brightness.
  class BrightnessControlDelegate {
   public:
    virtual ~BrightnessControlDelegate() {}
  
    // Handles an accelerator-driven request to decrease or increase the screen
    // brightness.
    virtual bool HandleBrightnessDown(const ui::Accelerator& accelerator) = 0;
    virtual bool HandleBrightnessUp(const ui::Accelerator& accelerator) = 0;
  
    // Requests that the brightness be set to |percent|, in the range
    // [0.0, 100.0].  |gradual| specifies whether the transition to the new
    // brightness should be animated or instantaneous.
    virtual void SetBrightnessPercent(double percent, bool gradual) = 0;
  
    // Asynchronously invokes |callback| with the current brightness, in the range
    // [0.0, 100.0].
    virtual void GetBrightnessPercent(
        const base::Callback<void(double)>& callback) = 0;
  };
  
  }  // namespace ash
  
  #endif  // ASH_SYSTEM_BRIGHTNESS_BRIGHTNESS_CONTROL_DELEGATE_H_
  