Use a flag to switch between original skinmap model and an experimental model(use original skinmap by default). BUG= Review URL: https://codereview.webrtc.org/1776993004 Cr-Commit-Position: refs/heads/master@{#11956}
BUG=webrtc:5255 Review URL: https://codereview.webrtc.org/1466763002 Cr-Commit-Position: refs/heads/master@{#10800}