Update //build/android/OWNERS.

Remove owners who've left Chrome and add myself.

Change-Id: Icd28c0432ba688b4e5cff23310425e93f3d7ab09
Reviewed-on: https://chromium-review.googlesource.com/1037934Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555379}

build/android/OWNERS

+estevenson@chromium.org
 jbudorick@chromium.org
-mikecase@chromium.org
 pasko@chromium.org
 perezju@chromium.org
-rnephew@chromium.org
 
 # COMPONENT: Test>Android