Also unifies the mock inheritance if they inherited from a ref counted interface: - it should only inherit from the interface - it should use make_ref_counted Bug: webrtc:14594 Change-Id: I7b0514b632ccd0798028b50f19812ac0a196e13c Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/262423 Commit-Queue: Florent Castelli <orphis@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#38602}