Fill NotificationActionInfo with actual values

This finishes the NotificationActionInfo mojo struct with all required
members and implements the browser & utility process sides of it. This
allows us to properly handle notification actions triggered by the
utility process.

Bug: 1170731
Change-Id: Icc1a2b9bf3f7ec0fa20c633d1b7c65dbcd77c45c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2705394
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Commit-Queue: Richard Knoll <knollr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#855953}