Remove dubroy@ from some OWNERS files. He doesn't work on Chrome anymore :(.

R=estade@chromium.org
BUG=none

Review URL: https://codereview.chromium.org/596883002

Cr-Commit-Position: refs/heads/master@{#296264}

chrome/browser/resources/OWNERS

 arv@chromium.org
 bauerb@chromium.org
 dbeam@chromium.org
-dubroy@chromium.org
 estade@chromium.org
 jhawkins@chromium.org
 nkostylev@chromium.org

chrome/browser/resources/history/OWNERS

-dubroy@chromium.org
+dbeam@chromium.org

chrome/browser/ui/webui/OWNERS

 arv@chromium.org
 bauerb@chromium.org
 dbeam@chromium.org
-dubroy@chromium.org
 estade@chromium.org
 jhawkins@chromium.org
 nkostylev@chromium.org

ui/webui/OWNERS

 arv@chromium.org
 bauerb@chromium.org
 dbeam@chromium.org
-dubroy@chromium.org
 estade@chromium.org
 jhawkins@chromium.org
 nkostylev@chromium.org