libaaudio: implement getTimestamp for legacy path

Fix: 36659408
Test: CTS test_aaudio.cpp
Signed-off-by: Phil Burk <philburk@google.com>

Change-Id: Ic73e69a3747b2daa1df5757650f897a58511e571
diff --git a/media/libaaudio/src/legacy/AudioStreamTrack.h b/media/libaaudio/src/legacy/AudioStreamTrack.h
index 1de07ce..7a53022 100644
--- a/media/libaaudio/src/legacy/AudioStreamTrack.h
+++ b/media/libaaudio/src/legacy/AudioStreamTrack.h
@@ -47,9 +47,7 @@
 
     virtual aaudio_result_t getTimestamp(clockid_t clockId,
                                        int64_t *framePosition,
-                                       int64_t *timeNanoseconds) override {
-        return AAUDIO_ERROR_UNIMPLEMENTED; // TODO call getTimestamp(ExtendedTimestamp *timestamp);
-    }
+                                       int64_t *timeNanoseconds) override;
 
     virtual aaudio_result_t write(const void *buffer,
                              int32_t numFrames,