GitLab

Removes:
* feature
* previews type
* assoc params
* triggering logic

PreviewsState bit will come in the next CL.

Bug: 944286
Change-Id: I65410f30d1efa574a391d61723fd6788b2d2d66d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1642018
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667188}