Add optional parameter to IVsyncSource::vsyncDeadlineAfter

vsyncDeadlineAfter just forwards its parameter to
VSyncTracker::nextAnticipatedVSyncTimeFrom, but the latter has an
optional parameter, too. Adding the optional parameter to
vsyncDeadlineAfter allows Scheduler::getNextFrameInterval to call it
directly. This will further help to move getNextFrameInterval's impl
into FrameTargeter::beginFrame, in
I229e09ccd760341268423fd4ba1ecc5105186f10.

Use Android's TimePoint and related classes directly in
getNextFrameInterval.

Bug: 315371484
Test: atest libscheduler_test:SchedulerTest#nextFrameIntervalTest
Change-Id: I1ede36d692b82a1f7276071fa558decced743334
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index fff97f7..c76d4bd 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -646,13 +646,13 @@
         return Fps{};
     }
     const Display& display = *displayOpt;
-    const nsecs_t threshold =
-            display.selectorPtr->getActiveMode().modePtr->getVsyncRate().getPeriodNsecs() / 2;
-    const nsecs_t nextVsyncTime =
-            display.schedulePtr->getTracker()
-                    .nextAnticipatedVSyncTimeFrom(currentExpectedPresentTime.ns() + threshold,
-                                                  currentExpectedPresentTime.ns());
-    return Fps::fromPeriodNsecs(nextVsyncTime - currentExpectedPresentTime.ns());
+    const Duration threshold =
+            display.selectorPtr->getActiveMode().modePtr->getVsyncRate().getPeriod() / 2;
+    const TimePoint nextVsyncTime =
+            display.schedulePtr->vsyncDeadlineAfter(currentExpectedPresentTime + threshold,
+                                                    currentExpectedPresentTime);
+    const Duration frameInterval = nextVsyncTime - currentExpectedPresentTime;
+    return Fps::fromPeriodNsecs(frameInterval.ns());
 }
 
 void Scheduler::resync() {