[dbus] Use base::Contains() instead of std::find() in //dbus

Use base::Contains() instead of std::find() where appropriate in
//dbus.

Bug: 561800
Change-Id: Id31974ee5e7c559e5d1df6836586fda52ee228af
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4783169
Commit-Queue: Ho Cheung <uioptt24@gmail.com>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1184198}
NOKEYCHECK=True
GitOrigin-RevId: 361ebe3b561c196adb2d35ce580a1251155e3f68
3 files changed