Properly reset the number of frames we think we've written to the audio sink

in order to compute the final delay before posting end-of-stream correctly.

Change-Id: I4ff6d7142fdf1ea2d19d12ec78c1e84322d22e5f
related-to-bug: 5216930

media/libstagefright/AudioPlayer.cpp

@@ -180,6 +180,8 @@ void AudioPlayer::pause(bool playPendingSamples) {
         } else {
             mAudioTrack->stop();
         }
+
+        mNumFramesPlayed = 0;
     } else {
         if (mAudioSink.get() != NULL) {
             mAudioSink->pause();