aw: Change OWNERS of gin java bridge renderer side.

Probably missed from https://codereview.chromium.org/1860703002, remove
mnaganov@chromium.org and add michaelbai@chromium.org per that CL.

Bug: None
Change-Id: I9b53713260e5ab9cbc1a819659b31efbed283dd3
Reviewed-on: https://chromium-review.googlesource.com/c/1471517Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632702}

content/renderer/java/OWNERS

-mnaganov@chromium.org
+michaelbai@chromium.org
 torne@chromium.org