Revert "NdkMediaExtractor: per-sample format metadata API"

This reverts commit 062ffd042fcbd237f445d499bc8ea8c5baf61d98.

Bug: 63934228
Bug: 74089496

Reason for revert: original change bypassed presubmit, causing mediaextractor crash, 

Change-Id: Iac4c49659dfa7415908d60da98a2285c583a1196
diff --git a/media/libmediaplayer2/nuplayer2/GenericSource2.cpp b/media/libmediaplayer2/nuplayer2/GenericSource2.cpp
index 936fb20..790581a 100644
--- a/media/libmediaplayer2/nuplayer2/GenericSource2.cpp
+++ b/media/libmediaplayer2/nuplayer2/GenericSource2.cpp
@@ -1239,7 +1239,7 @@
     }
 
     if (trackType == MEDIA_TRACK_TYPE_SUBTITLE) {
-        meta->setInt32(AMEDIAFORMAT_KEY_TRACK_INDEX, mSubtitleTrack.mIndex);
+        meta->setInt32("trackIndex", mSubtitleTrack.mIndex);
     }
 
     uint32_t dataType; // unused
@@ -1255,7 +1255,7 @@
     if (mb->meta_data().findData(
             kKeyMpegUserData, &dataType, &mpegUserDataPointer, &mpegUserDataLength)) {
         sp<ABuffer> mpegUserData = ABuffer::CreateAsCopy(mpegUserDataPointer, mpegUserDataLength);
-        meta->setBuffer(AMEDIAFORMAT_KEY_MPEG_USER_DATA, mpegUserData);
+        meta->setBuffer("mpegUserData", mpegUserData);
     }
 
     mb->release();