simplifying the validation BUG=webrtc:12575 Change-Id: I3f43347aec653ac0297523cda88f9101c57fe1c8 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/211867 Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34392}