That way we can drop PatternRewriter::scope_ and just use parser_->scope()
instead.

Change-Id: I66137d3ff8e7b805afc7108fd2d55537f69f11e6
Reviewed-on: https://chromium-review.googlesource.com/c/1387500Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58432}