Support using CSS Calc in non-length numeric properties

When mapping CSSPrimitiveValues to primitive numeric types we fail to
consider the case where it is a CSS Calc value. This patch adds support
for using CSS Calc in non-length numeric properties like tab-size and
opacity.

BUG=328998

Review URL: https://codereview.chromium.org/114593004

git-svn-id: svn://svn.chromium.org/blink/trunk@165610 bbb929c8-8fbe-4397-9dbb-9b2b20218538