mediaplayer: use non-blocking mode for AudioSink::write().

This cherry picks https://googleplex-android-review.git.corp.google.com/#/c/643541/ to master.

Bug: 19448263
Change-Id: I43dea830212de79c2b080185b6c6b36078f517d2
diff --git a/media/libmediaplayerservice/MediaPlayerService.h b/media/libmediaplayerservice/MediaPlayerService.h
index 7320311..4ce4b81 100644
--- a/media/libmediaplayerservice/MediaPlayerService.h
+++ b/media/libmediaplayerservice/MediaPlayerService.h
@@ -97,7 +97,7 @@
                 const audio_offload_info_t *offloadInfo = NULL);
 
         virtual status_t        start();
-        virtual ssize_t         write(const void* buffer, size_t size);
+        virtual ssize_t         write(const void* buffer, size_t size, bool blocking = true);
         virtual void            stop();
         virtual void            flush();
         virtual void            pause();