MediaCodec refactoring part 1-c: buffer ownership

- Buffers are (roughly) owned by themselves.
- As a corollary, remove output format change related events
and replace by inspecting formats associated with each buffers.

Bug: 32133435
Test: gts-tradefed run gts -m GtsExoPlayerTestCases
Test: (manual) Run Play Movies app to play a secure content.
Change-Id: I6b57da61c2d71acd0d5be4281de823ba1c95b72f
diff --git a/media/libmedia/MediaCodecBuffer.cpp b/media/libmedia/MediaCodecBuffer.cpp
index 2d255be..2af31d0 100644
--- a/media/libmedia/MediaCodecBuffer.cpp
+++ b/media/libmedia/MediaCodecBuffer.cpp
@@ -80,4 +80,8 @@
     return mFormat;
 }
 
+sp<MediaCodecBuffer> MediaCodecBuffer::clone(const sp<AMessage> &format) {
+    return new MediaCodecBuffer(format, mBuffer);
+}
+
 }  // namespace android