This callback is enabled via the method AudioCodingModule::RegisterVADCallback, which is unused, and deleted in this cl. Bug: None Change-Id: I04c8690fbb673305e69fe5b1c32d88efd6c72d1b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/148420 Reviewed-by: Minyue Li <minyue@webrtc.org> Commit-Queue: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30735}