Add support for reduced size mode. Bug: webrtc:8239 Change-Id: I1d646f0d7848af6632c9204ce5b96ae24cfc0ad3 Reviewed-on: https://webrtc-review.googlesource.com/23681 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20812}