a53472940e
Added VoipDtmf in VoipEngine as a sub-API to provide DTMF related interfaces; also added relevant unit tests. Bug: webrtc:11802 Change-Id: Ie9832aebe075a48ae1207be142361b73646673ca Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/180225 Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Reviewed-by: Tim Na <natim@webrtc.org> Reviewed-by: Per Åhgren <peah@webrtc.org> Commit-Queue: Tim Na <natim@webrtc.org> Cr-Commit-Position: refs/heads/master@{#31974}