text: // Copyright (c) 2013 The Chromium OS 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 POWER_MANAGER_POWERD_SYSTEM_AMBIENT_LIGHT_OBSERVER_H_
  #define POWER_MANAGER_POWERD_SYSTEM_AMBIENT_LIGHT_OBSERVER_H_
  
  #include <base/observer_list_types.h>
  
  namespace power_manager {
  namespace system {
  
  class AmbientLightSensorInterface;
  
  // Interface for classes interested in receiving updates about the ambient
  // light level from AmbientLightSensor.
  class AmbientLightObserver : public base::CheckedObserver {
   public:
    virtual ~AmbientLightObserver() {}
  
    // Called when the light level is measured. The measured level may be
    // unchanged from the previously-observed level.
    virtual void OnAmbientLightUpdated(AmbientLightSensorInterface* sensor) = 0;
  };
  
  }  // namespace system
  }  // namespace power_manager
  
  #endif  // POWER_MANAGER_POWERD_SYSTEM_AMBIENT_LIGHT_OBSERVER_H_
  