Allow C++17 structured bindings in Chromium.

Change-Id: Ide96e30476210db59c67c17a950e5b9aed679249
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3356325


Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Roland Bock <rbock@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958211}