SF: remove DispSyncSource

DispSyncSource is a legacy reminder of DispSync which was removed
a while ago. This changes removes the DispSyncSource and instead use
the VsyncDispatch interface directly.

Test: SF unit tests
Bug: 255601557
Bug: 256196556
Change-Id: I4247c3927b9ee9443437bf960f8cedc29759c4ac
diff --git a/services/surfaceflinger/Scheduler/VSyncDispatch.h b/services/surfaceflinger/Scheduler/VSyncDispatch.h
index 2bfe204..9520131 100644
--- a/services/surfaceflinger/Scheduler/VSyncDispatch.h
+++ b/services/surfaceflinger/Scheduler/VSyncDispatch.h
@@ -126,6 +126,17 @@
      */
     virtual ScheduleResult schedule(CallbackToken token, ScheduleTiming scheduleTiming) = 0;
 
+    /*
+     * Update the timing information for a scheduled callback.
+     * If the callback is not scheduled, then this function does nothing.
+     *
+     * \param [in] token           The callback to schedule.
+     * \param [in] scheduleTiming  The timing information for this schedule call
+     * \return                     The expected callback time if a callback was scheduled.
+     *                             std::nullopt if the callback is not registered.
+     */
+    virtual ScheduleResult update(CallbackToken token, ScheduleTiming scheduleTiming) = 0;
+
     /* Cancels a scheduled callback, if possible.
      *
      * \param [in] token    The callback to cancel.
@@ -159,6 +170,9 @@
     // See documentation for VSyncDispatch::schedule.
     ScheduleResult schedule(VSyncDispatch::ScheduleTiming scheduleTiming);
 
+    // See documentation for VSyncDispatch::update.
+    ScheduleResult update(VSyncDispatch::ScheduleTiming scheduleTiming);
+
     // See documentation for VSyncDispatch::cancel.
     CancelResult cancel();