Extend TestAudioDeviceModule API to be able to create WavReader/WavWriter from rtc::PlatformFile Bug: webrtc:8946 Change-Id: Ieea16be91c40a5928689cdeaa8a17d75fee0cf82 Reviewed-on: https://webrtc-review.googlesource.com/63266 Commit-Queue: Artem Titov <titovartem@webrtc.org> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Cr-Commit-Position: refs/heads/master@{#22576}