[Background] Change ownership of background mode

s/drew/devlin

Bug: 1117280
Change-Id: I4ef12d12f3f5c58c62257a86ae8e07aceb55f6ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2356166
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Drew Wilson <atwilson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798893}

chrome/browser/background/OWNERS

-atwilson@chromium.org
+rdevlin.cronin@chromium.org
+
+# TODO(devlin): Figure out the ownership and future of background mode.
+# https://crbug.com/1117280.
 
 # COMPONENT: Platform>Apps>BackgroundPage