Make sure that CSSSelector::setValue() is never called after parsing its pseudoType.
https://bugs.webkit.org/show_bug.cgi?id=111957

Reviewed by Hajime Morrita.

It'd be nice to have an assertion here since
CSSSelector::pseudoType() will never parse a new value after it
parses a value and m_pseudoType is set to non-PseudoNotParsed.

No new tests (no change in behaviour).

* css/CSSSelector.h:
(WebCore::CSSSelector::setValue):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145352 268f45cc-cd09-0410-ab3c-d52691b4dbfc