chromeos: Add screen-dim deferring to PowerManagerClient.

Make PowerManagerClient notify its observers about
ScreenDimImminent D-Bus signals from powerd, and expose a
new method that calls powerd's DeferScreenDim D-Bus method.

Bug: 854908
Change-Id: I28db70981ad44c6073db4ef90dd94180665012af
Reviewed-on: https://chromium-review.googlesource.com/1123410Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572051}

chromeos/dbus/fake_power_manager_client.cc

@@ -311,6 +311,10 @@ void FakePowerManagerClient::DeleteArcTimers(const std::string& tag,
       FROM_HERE, base::BindOnce(std::move(callback), true));
 }
 
+void FakePowerManagerClient::DeferScreenDim() {
+  num_defer_screen_dim_calls_++;
+}
+
 bool FakePowerManagerClient::PopVideoActivityReport() {
   CHECK(!video_activity_reports_.empty());
   bool fullscreen = video_activity_reports_.front();
@@ -364,6 +368,11 @@ void FakePowerManagerClient::SendPowerButtonEvent(
     observer.PowerButtonEventReceived(down, timestamp);
 }
 
+void FakePowerManagerClient::SendScreenDimImminent() {
+  for (auto& observer : observers_)
+    observer.ScreenDimImminent();
+}
+
 void FakePowerManagerClient::SetLidState(LidState state,
                                          const base::TimeTicks& timestamp) {
   lid_state_ = state;

chromeos/dbus/fake_power_manager_client.h

@@ -43,6 +43,7 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
   int num_set_is_projecting_calls() const {
     return num_set_is_projecting_calls_;
   }
+  int num_defer_screen_dim_calls() const { return num_defer_screen_dim_calls_; }
   double screen_brightness_percent() const {
     return screen_brightness_percent_.value();
   }
@@ -111,6 +112,7 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
                      VoidDBusMethodCallback callback) override;
   void DeleteArcTimers(const std::string& tag,
                        VoidDBusMethodCallback callback) override;
+  void DeferScreenDim() override;
 
   // Pops the first report from |video_activity_reports_|, returning whether the
   // activity was fullscreen or not. There must be at least one report.
@@ -135,6 +137,9 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
   // Notifies observers that the power button has been pressed or released.
   void SendPowerButtonEvent(bool down, const base::TimeTicks& timestamp);
 
+  // Notifies observers that the screen is about to be dimmed.
+  void SendScreenDimImminent();
+
   // Sets |lid_state_| or |tablet_mode_| and notifies |observers_| about the
   // change.
   void SetLidState(LidState state, const base::TimeTicks& timestamp);
@@ -192,6 +197,7 @@ class CHROMEOS_EXPORT FakePowerManagerClient : public PowerManagerClient {
   int num_set_policy_calls_ = 0;
   int num_set_is_projecting_calls_ = 0;
   int num_set_backlights_forced_off_calls_ = 0;
+  int num_defer_screen_dim_calls_ = 0;
 
   // Number of pending suspend readiness callbacks.
   int num_pending_suspend_readiness_callbacks_ = 0;

chromeos/dbus/power_manager_client.cc

@@ -463,6 +463,10 @@ class PowerManagerClientImpl : public PowerManagerClient {
         base::BindOnce(&OnVoidDBusMethod, std::move(callback)));
   }
 
+  void DeferScreenDim() override {
+    SimpleMethodCallToPowerManager(power_manager::kDeferScreenDimMethod);
+  }
+
  protected:
   void Init(dbus::Bus* bus) override {
     power_manager_proxy_ = bus->GetObjectProxy(
@@ -496,6 +500,8 @@ class PowerManagerClientImpl : public PowerManagerClient {
          &PowerManagerClientImpl::SuspendDoneReceived},
         {power_manager::kDarkSuspendImminentSignal,
          &PowerManagerClientImpl::DarkSuspendImminentReceived},
+        {power_manager::kScreenDimImminentSignal,
+         &PowerManagerClientImpl::ScreenDimImminentReceived},
         {power_manager::kIdleActionImminentSignal,
          &PowerManagerClientImpl::IdleActionImminentReceived},
         {power_manager::kIdleActionDeferredSignal,
@@ -886,6 +892,11 @@ class PowerManagerClientImpl : public PowerManagerClient {
     base::PowerMonitorDeviceSource::HandleSystemResumed();
   }
 
+  void ScreenDimImminentReceived(dbus::Signal* signal) {
+    for (auto& observer : observers_)
+      observer.ScreenDimImminent();
+  }
+
   void IdleActionImminentReceived(dbus::Signal* signal) {
     dbus::MessageReader reader(signal);
     power_manager::IdleActionImminent proto;

chromeos/dbus/power_manager_client.h

@@ -133,6 +133,9 @@ class CHROMEOS_EXPORT PowerManagerClient : public DBusClient {
     virtual void TabletModeEventReceived(TabletMode mode,
                                          const base::TimeTicks& timestamp) {}
 
+    // Called just before the screen is dimmed in response to user inactivity.
+    virtual void ScreenDimImminent() {}
+
     // Called when the idle action will be performed after
     // |time_until_idle_action|.
     virtual void IdleActionImminent(
@@ -298,6 +301,11 @@ class CHROMEOS_EXPORT PowerManagerClient : public DBusClient {
   virtual void DeleteArcTimers(const std::string& tag,
                                VoidDBusMethodCallback callback) = 0;
 
+  // Instructs powerd to defer dimming the screen. This only has an effect when
+  // called shortly (i.e. seconds) after observers have received
+  // ScreenDimImminent notifications.
+  virtual void DeferScreenDim() = 0;
+
   // Creates the instance.
   static PowerManagerClient* Create(DBusClientImplementationType type);