Add implementation for clipping prediction and clipped level step estimation. Bug: webrtc:12774 Change-Id: I855d22980302aac7d49078ca29755f9422af9cb5 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/220935 Commit-Queue: Hanna Silen <silen@webrtc.org> Reviewed-by: Minyue Li <minyue@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34206}