[Extensions] gn check more targets from //extensions/browser

There are a few targets we can get to trivially pass gn check from
//extensions/browser. Add them.

Bug: None
Change-Id: If8c18b57300d1c8a8246a85bcbfbfdec43b7a9a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625859
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663042}
3 files changed