Like aom and openh264, VP9 can be disabled with the gn argument. Bug: None Change-Id: I7d67e3946afae0bb4cac8a7e591445604dda9ce1 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215260 Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33737}