Improvement to my previous patch, suggested by Darin

        * dom/Document.cpp:
        (WebCore::Document::repaintMarkers):
        new method, similar in structure to removeMarkers but just repaints each node that
        has a marker of the specified type
        * dom/Document.h:
        declare new method, and tweak style in related method declarations
        
        * page/Frame.cpp:
        (WebCore::Frame::setMarkedTextMatchesAreHighlighted):
        if the value changes, call repaintMarkers



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@14455 268f45cc-cd09-0410-ab3c-d52691b4dbfc