NuPlayer: do not create audio decoder if the player is still in shutdown process.

Bug: 23350795
Change-Id: I46b02cf31d7d4447806910a9ecd8c3bda05f2f5b
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
index 77b9799..c0146d5 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayer.cpp
@@ -1488,7 +1488,9 @@
 }
 
 status_t NuPlayer::instantiateDecoder(bool audio, sp<DecoderBase> *decoder) {
-    if (*decoder != NULL) {
+    // The audio decoder could be cleared by tear down. If still in shut down
+    // process, no need to create a new audio decoder.
+    if (*decoder != NULL || (audio && mFlushingAudio == SHUT_DOWN)) {
         return OK;
     }