[Night Light] CL4: Automatic schedule backend.

ash/system/night_light/night_light_controller.h

Index: ash/system/night_light/night_light_controller.h
diff --git a/ash/system/night_light/night_light_controller.h b/ash/system/night_light/night_light_controller.h
index 8066d7c1ca45f55ac4a8e1353a0f54d89959a97d..93fdb7b302c95d6089f2ac96898998f5fbf1e4e1 100644
--- a/ash/system/night_light/night_light_controller.h
+++ b/ash/system/night_light/night_light_controller.h
@@ -9,7 +9,10 @@
 
 #include "ash/ash_export.h"
 #include "ash/session/session_observer.h"
+#include "ash/system/night_light/time_of_day.h"
 #include "base/observer_list.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
 #include "components/prefs/pref_change_registrar.h"
 
 class PrefRegistrySimple;
@@ -23,6 +26,46 @@ class SessionController;
 // screen.
 class ASH_EXPORT NightLightController : public SessionObserver {
  public:
+  enum class ScheduleType : int {
+    // Automatic toggling of NightLight is turned off.
+    kNone = 0,
+
+    // Turned automatically on at the user's local sunset time, and off at the
+    // user's local sunrise time.
+    kSunsetToSunrise = 1,
+
+    // Toggled automatically based on the custom set start and end times
+    // selected by the user from the system settings.
+    kCustom = 2,
+  };
+
+  enum class AnimationDurationType {
+    // Short animation (2 seconds) used for manual changes of NightLight status
+    // and temperature by the user.
+    kShort,
+
+    // Long animation (20 seconds) used for applying the color temperature
+    // gradually as a result of getting into or out of the automatically
+    // scheduled NightLight mode. This gives the user a smooth transition.
+    kLong,
+  };
+
+  // This class enables us to inject fake values for "Now" as well as the sunset
+  // and sunrise times, so that we can reliably test the behavior in various
+  // schedule types and times.
+  class Delegate {
+   public:
+    // NightLightController owns the delegate.
+    virtual ~Delegate() {}
+
+    // Gets the current time.
+    virtual base::Time GetNow() const = 0;
+
+    // Gets the sunset and sunrise times.
+    virtual base::Time GetSunsetTime() const = 0;
+    virtual base::Time GetSunriseTime() const = 0;
+  };
+
   class Observer {
    public:
     // Emitted when the NightLight status is changed.
@@ -37,24 +80,40 @@ class ASH_EXPORT NightLightController : public SessionObserver {
 
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
+  AnimationDurationType animation_type() const { return animation_type_; }
+  AnimationDurationType last_animation_type() const {
+    return last_animation_type_;
+  }
+  const base::OneShotTimer& timer() const { return timer_; }
+
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Get the NightLight settings stored in the current active user prefs.
   bool GetEnabled() const;
   float GetColorTemperature() const;
+  ScheduleType GetScheduleType() const;
+  TimeOfDay GetCustomStartTime() const;
+  TimeOfDay GetCustomEndTime() const;
 
   // Set the desired NightLight settings in the current active user prefs.
-  void SetEnabled(bool enabled);
+  void SetEnabled(bool enabled, AnimationDurationType animation_type);
   void SetColorTemperature(float temperature);
+  void SetScheduleType(ScheduleType type);
+  void SetCustomStartTime(TimeOfDay start_time);
+  void SetCustomEndTime(TimeOfDay end_time);
 
+  // This is always called as a result of a user action and will always use the
+  // AnimationDurationType::kShort.
   void Toggle();
 
   // ash::SessionObserver:
   void OnActiveUserSessionChanged(const AccountId& account_id) override;
 
+  void SetDelegateForTesting(std::unique_ptr<Delegate> delegate);
+
  private:
-  void Refresh();
+  void RefreshLayersTemperature();
 
   void StartWatchingPrefsChanges();
 
@@ -68,14 +127,50 @@ class ASH_EXPORT NightLightController : public SessionObserver {
   // Called when the user pref for the color temperature is changed.
   void OnColorTemperaturePrefChanged();
 
+  // Called when any of the schedule related prefs (schedule type, custom start
+  // and end times) are changed.
+  void OnScheduleParamsPrefsChanged();
+
+  // Refreshes the state of NightLight according to the currently set
+  // parameters. |did_schedule_change| is true when Refresh() is called as a
+  // result of a change in one of the schedule related prefs, and false
+  // otherwise.
+  void Refresh(bool did_schedule_change);
+
+  // Given the desired start and end times that determine the time interval
+  // during which NightLight will be ON, depending on the time of "now", it
+  // refreshes the |timer_| to either schedule the future start or end of
+  // NightLight mode, as well as update the current status if needed.
+  // For |did_schedule_change|, see Refresh() above.
+  // This function should never be called if the schedule type is |kNone|.
+  void RefreshScheduleTimer(base::Time start_time,
+                            base::Time end_time,
+                            bool did_schedule_change);
+
+  // Schedule the upcoming next toggle of NightLight mode. This is used for the
+  // automatic status changes of NightLight which always use an
+  // AnimationDurationType::kLong.
+  void ScheduleNextToggle(base::TimeDelta delay);
+
   // The observed session controller instance from which we know when to
   // initialize the NightLight settings from the user preferences.
   SessionController* const session_controller_;
 
+  std::unique_ptr<Delegate> delegate_;
+
   // The pref service of the currently active user. Can be null in
   // ash_unittests.
   PrefService* active_user_pref_service_ = nullptr;
 
+  // The animation type for any upcoming future change.
+  AnimationDurationType animation_type_ = AnimationDurationType::kShort;
+  // The animation type of the change that was just performed.
+  AnimationDurationType last_animation_type_ = AnimationDurationType::kShort;
+
+  // The timer that schedules the start and end of NightLight when the schedule
+  // type is either kSunsetToSunrise or kCustom.
+  base::OneShotTimer timer_;
+
   // The registrar used to watch NightLight prefs changes in the above
   // |active_user_pref_service_| from outside ash.
   // NOTE: Prefs are how Chrome communicates changes to the NightLight settings