- Avoid static methods.
- Instantiate the actual visitor on the stack.
- Get rid of unnecessary abstractions.

Bug: chromium:738865
Change-Id: I4115d7b88f17a7118aa9ee129eb39a28ec413696
Reviewed-on: https://chromium-review.googlesource.com/558878
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46384}