This will make it easier to separate out parameter declaration from other other
parameter scope information tracking.

Change-Id: I8712dd7fc589c84bc1e1a1eab9038af6047b21cd
Reviewed-on: https://chromium-review.googlesource.com/c/1403118
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58698}