Add width consumer for the location bar buttons

This adds a new ToolbarWidthConsumer for the location bar's buttons
(install, mic, lens, bookmark). The exact order is arbitrary, as
the buttons are all roughly the same priority other than the bookmark
button being the highest priority to keep visible.

https://screencast.googleplex.com/cast/NDkzNjUwODY4MjI3Mjc2OHwyZjNlYjhlMC00ZA

Bug: 427260734
Change-Id: Icf0ed2bcf86886ee7806d8c7bd4d9c081268debe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6945458
Reviewed-by: Patrick Noland <pnoland@chromium.org>
Commit-Queue: Charles Hager <clhager@google.com>
Reviewed-by: Sirisha Kavuluru <skavuluru@google.com>
Cr-Commit-Position: refs/heads/main@{#1524367}