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/include/media/MediaCodecBuffer.h b/include/media/MediaCodecBuffer.h
index 2df81dd..05aaa14 100644
--- a/include/media/MediaCodecBuffer.h
+++ b/include/media/MediaCodecBuffer.h
@@ -58,6 +58,8 @@
     sp<AMessage> meta();
     sp<AMessage> format();
 
+    virtual sp<MediaCodecBuffer> clone(const sp<AMessage> &format);
+
 private:
     MediaCodecBuffer() = delete;