aaudio: improve accuracy of timestamps

Account for latency added by the AAudio service.
Fix input timestamps.

Bug: 37080396
Test: test_timestamps.cpp input_monitor.cpp
Change-Id: I1053cd21af722bb9b9371df4e5731bf4a0a57b0b
diff --git a/services/oboeservice/AAudioServiceEndpoint.h b/services/oboeservice/AAudioServiceEndpoint.h
index e40a670..603d497 100644
--- a/services/oboeservice/AAudioServiceEndpoint.h
+++ b/services/oboeservice/AAudioServiceEndpoint.h
@@ -69,6 +69,8 @@
         mReferenceCount = count;
     }
 
+    aaudio_result_t getTimestamp(int64_t *positionFrames, int64_t *timeNanos);
+
     bool matches(const AAudioStreamConfiguration& configuration);
 
     virtual AudioStreamInternal *getStreamInternal() = 0;