Refactor VideoDenoiser to work with I420Buffer, not VideoFrame.

BUG=webrtc:5921
R=jackychen@webrtc.org, marpan@webrtc.org

Review URL: https://codereview.webrtc.org/2005733003 .

Cr-Original-Commit-Position: refs/heads/master@{#13179}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 6af2e86b46a638f8a9309dffc3181053bd32974e
7 files changed