Bug 111011: getPropertyValue for -webkit-columns returns null, should compute the shorthand value

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

PASS webkitColumnsValue("columns1") is "10px"
PASS webkitColumnsValue("columns2") is "10"
PASS webkitColumnsValue("columns3") is "10px"
PASS webkitColumnsValue("columns4") is "auto"
PASS webkitColumnsValue("columns5") is "2"
NOTE: 'foo' is an illegal CSS value for '-webkit-columns'.
PASS webkitColumnsValue("columns8") is ""
NOTE: If only few longhand properties are specified, getPropertyValue for shorthand property returns empty string.
PASS webkitColumnsValue("columns9") is ""
PASS successfullyParsed is true

TEST COMPLETE