Added HAVE(ACCESSIBILITY) header guards to platform implementation
        source files.

        * page/gtk/AccessibilityObjectAtk.cpp: Added HAVE(ACCESSIBILITY)
        guards.
        * page/gtk/AccessibilityObjectWrapperAtk.cpp: Ditto.
        * page/qt/AccessibilityObjectQt.cpp: Ditto.
        * page/win/AccessibilityObjectWin.cpp: Ditto.
        * page/wx/AccessibilityObjectWx.cpp: Ditto.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@38244 268f45cc-cd09-0410-ab3c-d52691b4dbfc