calc expressions should support time, angle and frequency values.

According to the CSS3 standard calc() expressions can contain time,
angle and frequency values. (http://www.w3.org/TR/css3-values/#calc).
The patch implements this feature.

The patch is partially based on http://trac.webkit.org/changeset/168685
and http://trac.webkit.org/changeset/170544 (Patch by Martin Hodovan,
reviewers were: Darin Adler and Simon Fraser)

R=mikelawther@chromium.org,alancutter@chromium.org
BUG=390566

Review URL: https://codereview.chromium.org/345903005

git-svn-id: svn://svn.chromium.org/blink/trunk@179101 bbb929c8-8fbe-4397-9dbb-9b2b20218538