Reviewed by Darin Adler.

        Fix percentage values in radius of radial gradients
        https://bugs.webkit.org/show_bug.cgi?id=51979

        Handle percentage values for the ending size of radial gradients.

        Test: fast/gradients/css3-radial-gradients3.html

        * css/CSSGradientValue.cpp:
        (WebCore::CSSRadialGradientValue::resolveRadius): Add parameter for height or width, which is
        non-null if percentage values are allowed, and compute percentage values when we see them.
        (WebCore::CSSRadialGradientValue::createGradient): Pass height or width down to say that
        percentages are OK when resolving end radii.
        * css/CSSGradientValue.h: New parameter for resolveRadius.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@75136 268f45cc-cd09-0410-ab3c-d52691b4dbfc