Remove linked_ptr from the extensions rules registry.

BUG=582001

Change-Id: Ia2abb1393718c8c0aa54a350ccc065077e362870
Reviewed-on: https://chromium-review.googlesource.com/c/1363797
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615702}
21 files changed