<rdar://problem/3942647> Support AXStyleTextMarkerRangeForTextMarker parameterized attribute

        * bridge/mac/WebCoreAXObject.mm:
        (-[WebCoreAXObject accessibilityParameterizedAttributeNames]):
        Add AXStyleTextMarkerRangeForTextMarker.
        
        (startOfStyleRange):
        (endOfStyleRange):
        Return first/last VisiblePosition in range having the same style has the specified VisiblePosition.

        (-[WebCoreAXObject doAXStyleTextMarkerRangeForTextMarker:]):
        Return AXTextMarkerRange for startOfStyleRange/endOfStyleRange of the specified AXTextMarker.
        
        (-[WebCoreAXObject accessibilityAttributeValue:forParameter:]):
        Call doAXStyleTextMarkerRangeForTextMarker for AXStyleTextMarkerRangeForTextMarker.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@16072 268f45cc-cd09-0410-ab3c-d52691b4dbfc