NuPlayerDecoder: check mCodec before dereferencing it.

Test: media cts tests
Bug: 37538141
Change-Id: Ib95fd4786242d6742f3bdc7aab28f79d43e8da81
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h b/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
index dcdfcaf..d44c396 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerDecoderBase.h
@@ -69,6 +69,8 @@
 
     virtual ~DecoderBase();
 
+    void stopLooper();
+
     virtual void onMessageReceived(const sp<AMessage> &msg);
 
     virtual void onConfigure(const sp<AMessage> &format) = 0;