dashplayer: Replace ACodec with DashCodec

- Enable smooth streaming.
- Notify flush completed for all states except executing.
  This prevents crash on seek, when seekbar is dragged.

Change-Id: I9cd15194002c93ce1a411aa4abbded9d13be5701
diff --git a/dashplayer/DashPlayerDecoder.h b/dashplayer/DashPlayerDecoder.h
index 3bb471c..adf7544 100644
--- a/dashplayer/DashPlayerDecoder.h
+++ b/dashplayer/DashPlayerDecoder.h
@@ -50,7 +50,7 @@
     sp<AMessage> mNotify;
     sp<NativeWindowWrapper> mNativeWindow;
 
-    sp<ACodec> mCodec;
+    sp<DashCodec> mCodec;
     sp<ALooper> mCodecLooper;
     sp<MediaPlayerBase::AudioSink> mAudioSink;
     sp<Renderer> mRenderer;