[Night Light] CL2: Ash and system tray work

ash/system/night_light/night_light_controller.cc

Index: ash/system/night_light/night_light_controller.cc
diff --git a/ash/system/night_light/night_light_controller.cc b/ash/system/night_light/night_light_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bf1cae453389a00c818fa2f3b9af12303634b1fd
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+++ b/ash/system/night_light/night_light_controller.cc
@@ -0,0 +1,142 @@
+// Copyright 2017 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.
+
+#include "ash/system/night_light/night_light_controller.h"
+
+#include "ash/session/session_controller.h"
+#include "ash/shell.h"
+#include "base/time/time.h"
+#include "base/values.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/scoped_user_pref_update.h"
+#include "ui/compositor/layer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+
+namespace ash {
+
+namespace {
+
+// The key of the dictionary value in the user's pref service that contains all
+// the NightLight settings.
+constexpr char kNightLightPrefsKey[] = "prefs.night_light_prefs";
+
+// Keys to the various NightLight settings inside its dictionary value.
+constexpr char kStatusKey[] = "night_light_status";
+constexpr char kColorTemperatureKey[] = "night_light_color_temperature";
+
+// The duration of the temperature change animation when the change is a result
+// of a manual user setting.
+// TODO(afakhry): Add automatic schedule animation duration when you implement
+// that part. It should be large enough (20 seconds as agreed) to give the user
+// a nice smooth transition.
+constexpr int kManualToggleAnimationDurationSec = 2;
+
+}  // namespace
+
+NightLightController::NightLightController(
+    SessionController* session_controller)
+    : session_controller_(session_controller) {
+  session_controller_->AddObserver(this);
+}
+
+NightLightController::~NightLightController() {
+  session_controller_->RemoveObserver(this);
+}
+
+// static
+void NightLightController::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterDictionaryPref(kNightLightPrefsKey);
+}
+
+void NightLightController::AddObserver(Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void NightLightController::RemoveObserver(Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void NightLightController::Toggle() {
+  SetEnabled(!enabled_);
+}
+
+void NightLightController::SetEnabled(bool enabled) {
+  if (enabled_ == enabled)
+    return;
+
+  enabled_ = enabled;
+  Refresh();
+  NotifyStatusChanged();
+  PersistUserPrefs();
+}
+
+void NightLightController::SetColorTemperature(float temperature) {
+  // TODO(afakhry): Spport changing the temperature when you implement the
+  // settings part of this feature. Right now we'll keep it fixed at the value
+  // |color_temperature_| whenever NightLight is turned on.
+
+  for (aura::Window* root_window : Shell::GetAllRootWindows()) {
+    ui::Layer* layer = root_window->layer();
+
+    ui::ScopedLayerAnimationSettings settings(layer->GetAnimator());
+    settings.SetTransitionDuration(
+        base::TimeDelta::FromSeconds(kManualToggleAnimationDurationSec));
+    settings.SetPreemptionStrategy(
+        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+
+    layer->SetLayerTemperature(temperature);
+  }
+}
+
+void NightLightController::OnActiveUserSessionChanged(
+    const AccountId& account_id) {
+  // Initial login and user switching in multi profiles.
+  InitFromUserPrefs();
+}
+
+void NightLightController::Refresh() {
+  SetColorTemperature(enabled_ ? color_temperature_ : 0.0f);
+}
+
+void NightLightController::InitFromUserPrefs() {
+  auto* pref_service = Shell::Get()->GetActiveUserPrefService();
+  if (!pref_service) {
+    // The pref_service can be NULL in ash_unittests.
+    return;
+  }
+
+  const base::DictionaryValue* night_light_prefs =
+      pref_service->GetDictionary(kNightLightPrefsKey);
+  bool enabled = false;
+  night_light_prefs->GetBoolean(kStatusKey, &enabled);
+  enabled_ = enabled;
+
+  double color_temperature = 0.5;
+  night_light_prefs->GetDouble(kColorTemperatureKey, &color_temperature);
+  color_temperature_ = static_cast<float>(color_temperature);
+
+  Refresh();
+  NotifyStatusChanged();
+}
+
+void NightLightController::PersistUserPrefs() {
+  auto* pref_service = ash::Shell::Get()->GetActiveUserPrefService();
+  if (!pref_service) {
+    // The pref_service can be NULL in ash_unittests.
+    return;
+  }
+  DictionaryPrefUpdate pref_updater(pref_service, kNightLightPrefsKey);
+
+  base::DictionaryValue* dictionary = pref_updater.Get();
+  dictionary->SetBoolean(kStatusKey, enabled_);
+  dictionary->SetDouble(kColorTemperatureKey,
+                        static_cast<double>(color_temperature_));
+}
+
+void NightLightController::NotifyStatusChanged() {
+  for (auto& observer : observers_)
+    observer.OnNightLightEnabledChanged(enabled_);
+}
+
+}  // namespace ash