Modernise function to unified MOCK_METHOD macro, delete few deprecated functions on the way.
Remove default constructors to stress they do nothing special
Bug: None
Change-Id: Ie126f38f0589acb65886f25f754ca575c17af29b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/174583
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31191}