Add keishi@ to core/OWNERS.

NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/189463004

git-svn-id: svn://svn.chromium.org/blink/trunk@168698 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Suppress fast/css-generated-content/crash-selection-editing-removes-pseudo.html timeouts on oilpan mac dbg builds.

TBR=leviw
BUG=342574

Review URL: https://codereview.chromium.org/189363003

git-svn-id: svn://svn.chromium.org/blink/trunk@168699 bbb929c8-8fbe-4397-9dbb-9b2b20218538