Don't post position updates too frequently

i.e. don't hog my message queue.

related-to-bug: 5284760
Change-Id: I8e2d36a11dbee1567b18ed13dc5257a65c6eeda7
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
index 2713031..3a641a2 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerRenderer.h
@@ -74,6 +74,8 @@
         status_t mFinalResult;
     };
 
+    static const int64_t kMinPositionUpdateDelayUs;
+
     sp<MediaPlayerBase::AudioSink> mAudioSink;
     sp<AMessage> mNotify;
     List<QueueEntry> mAudioQueue;
@@ -98,6 +100,8 @@
 
     bool mPaused;
 
+    int64_t mLastPositionUpdateUs;
+
     void onDrainAudioQueue();
     void postDrainAudioQueue();