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}