Cannot compile with ENABLE_SHADOW_DOM=0 and ENABLE_STYLE_SCOPED=1
https://bugs.webkit.org/show_bug.cgi?id=106207

Reviewed by Hajime Morita.

Guard StyleScopeResolver::addHostRule with SHADOW_DOM flag.

No tests, as no change in behavior.

* css/StyleScopeResolver.cpp:
(WebCore):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@138929 268f45cc-cd09-0410-ab3c-d52691b4dbfc