Add kbr@chromium.org to Source/platform/OWNERS; already core/ OWNER.

BUG=

Review URL: https://codereview.chromium.org/102213010

git-svn-id: svn://svn.chromium.org/blink/trunk@164253 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Disable virtual forum-comments-autosizing.html.

BUG=330286

Review URL: https://codereview.chromium.org/120293002

git-svn-id: svn://svn.chromium.org/blink/trunk@164254 bbb929c8-8fbe-4397-9dbb-9b2b20218538