Minor comment nit fix

/shadow-deep/ -> /deep/
and one minor comment correction.

BUG=none
TEST=none

Review URL: https://codereview.chromium.org/334833002

git-svn-id: svn://svn.chromium.org/blink/trunk@176474 bbb929c8-8fbe-4397-9dbb-9b2b20218538