[Adaptation] Adaptation holds restrictions

This refactoring enables us to do multi-step adaptations
instead of the normal single step adaptations.

This work is required pre-requisite work to remove the
DropDueToSize methods from the ResourceAdaptationProcessorInterface.

This work also gives a path to fixing webrtc:11719, since double
adaptations can be done in a controlled manner with this API.


Bug: webrtc:11700,webrtc:11719
Change-Id: Ic7d27a49c82d0cf7ebaf79d7bdf0bc6f382770ed
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178200
Commit-Queue: Evan Shrubsole <eshr@google.com>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31631}