Functions to estimate pitch period and gain. Bug: webrtc:9076 Change-Id: Icfe9430dcae11bdb96165c5bfe6e2b1d3bf848ab Reviewed-on: https://webrtc-review.googlesource.com/70382 Commit-Queue: Alex Loiko <aleloi@webrtc.org> Reviewed-by: Per Åhgren <peah@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23066}