HW Vsync turns off correctly in Doze/AOD.

Otherwise when entering AOD mode, SF keeps HW Vsync on indefinitely,
leading to power inefficiency.

Bug: 219109873
Test: atest libsurfaceflinger_test
Test: perfetto trace
Change-Id: Idf80d4c64abe78593809be9d1ba6b7dd42d29054
diff --git a/services/surfaceflinger/Scheduler/VSyncReactor.h b/services/surfaceflinger/Scheduler/VSyncReactor.h
index 6a1950a..4501487 100644
--- a/services/surfaceflinger/Scheduler/VSyncReactor.h
+++ b/services/surfaceflinger/Scheduler/VSyncReactor.h
@@ -49,6 +49,8 @@
     bool addHwVsyncTimestamp(nsecs_t timestamp, std::optional<nsecs_t> hwcVsyncPeriod,
                              bool* periodFlushed) final;
 
+    void setDisplayPowerMode(hal::PowerMode powerMode) final;
+
     void dump(std::string& result) const final;
 
 private:
@@ -73,6 +75,8 @@
     std::optional<nsecs_t> mPeriodTransitioningTo GUARDED_BY(mMutex);
     std::optional<nsecs_t> mLastHwVsync GUARDED_BY(mMutex);
 
+    hal::PowerMode mDisplayPowerMode GUARDED_BY(mMutex) = hal::PowerMode::ON;
+
     const bool mSupportKernelIdleTimer = false;
 };