Remove unnecessary explicit keywords from a constructor with more than one parameters in css directory.

BUG=None
TEST=None; No behavior change

Review URL: https://codereview.chromium.org/710293002

git-svn-id: svn://svn.chromium.org/blink/trunk@185114 bbb929c8-8fbe-4397-9dbb-9b2b20218538