Instead of crashing with a CHECK fail when an insertable stream of a Video RTPSender is given a frame from an RTPReceiver's insertable stream, construct a reasonable analogous sender frame and pass it through to be decoded. A small step towards removing the split we have between Sender and Receiver implementations of TransformableFrameInterface which just confuses users of the API. Counterpart to https://webrtc-review.googlesource.com/c/src/+/301181 in the opposite direction. Bug: chromium:1250638 Change-Id: If66da7d553f14979ff1c5b4e00bff715f58cfce0 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/303480 Reviewed-by: Stefan Holmer <stefan@webrtc.org> Commit-Queue: Tony Herre <herre@google.com> Reviewed-by: Palak Agarwal <agpalak@google.com> Cr-Commit-Position: refs/heads/main@{#39963}