- clean up options for font code path

        * platform/Font.h:
        * platform/Font.cpp:
        (WebCore::Font::setCodePath): Added. Replaces boolean version.
        (WebCore::Font::canUseGlyphCache): Update to handle "never use complex" case too.

        * platform/mac/WebCoreTextRenderer.mm:
        (WebCoreSetAlwaysUseATSU): Change to call setCodePath.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@16594 268f45cc-cd09-0410-ab3c-d52691b4dbfc