Impl for supporting two video scaling modes

o allows the video scaling mode to change at any time
o also remove the scaling mode logic in OMXCodec.cpp

o related-to-bug: 5454345

Change-Id: I6f1714eb0c2774591ce650d56c1e779b8afd085f
diff --git a/include/media/mediaplayer.h b/include/media/mediaplayer.h
index a68ab4e..1fad383 100644
--- a/include/media/mediaplayer.h
+++ b/include/media/mediaplayer.h
@@ -162,6 +162,7 @@
     INVOKE_ID_ADD_EXTERNAL_SOURCE_FD = 3,
     INVOKE_ID_SELECT_TRACK = 4,
     INVOKE_ID_UNSELECT_TRACK = 5,
+    INVOKE_ID_SET_VIDEO_SCALING_MODE = 6,
 };
 
 // Keep MEDIA_TRACK_TYPE_* in sync with MediaPlayer.java.