In preparation for landing https://webrtc-review.googlesource.com/c/src/+/72441 a downstream project that uses the VideoCodingModule needs to be able to inject a decoder object created from the outside, just like how encoders are possible to inject. Bug: webrtc:7925 Change-Id: Ibaeffda55f84410436d79f75730e7352e298b9f0 Reviewed-on: https://webrtc-review.googlesource.com/77160 Commit-Queue: Anders Carlsson <andersc@webrtc.org> Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23297}