[Extensions] Use compiled feature files

Use generated compiled feature files instead of parsing the JSON at
runtime. In local testing, this shows an order-of-magnitude performance
increase, as well as catching a number of invalid features.

BUG=280286

Review-Url: https://codereview.chromium.org/2165023003
Cr-Commit-Position: refs/heads/master@{#407511}
35 files changed