[Fuchsia] Migrate ApplicationConfigManager from using struct to table.

Returning a table will allow new fields to be added without breaking
existing clients in future.

Bug: 914610
Change-Id: I88544844e394c6524fc130544299221be1c948e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1529722
Reviewed-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641807}
4 files changed