[Previews] Adds DeferAllScript support to Decider and OptGuide

Adds new opt guide proto optimization type for DeferAllScript with
whitelist checking for it from PreviewsDeciderImpl thru PreviewsHints.

Bug: 965277
Change-Id: I7be59e6eda9b64d310027ac2c3ddfb7f91ac76eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1673754
Reviewed-by: Robert Ogden <robertogden@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Doug Arnett <dougarnett@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672122}
7 files changed