Reviewed by Beth.

        Fix: <rdar://problem/4939672> REGRESSION: With text selected that is
        not a link, the "Remove Link" contextual menu item remains active

        * platform/ContextMenuItem.h: Added enabled method.
        * platform/qt/ContextMenuItemQt.cpp:
        (WebCore::ContextMenuItem::enabled): Implemented.
        * platform/mac/ContextMenuItemMac.mm:
        (WebCore::ContextMenuItem::enabled): Ditto.
        * platform/mac/ContextMenuMac.mm:
        (-[WebCoreMenuTarget validateMenuItem:]): Implemented to fulfill the
        NSMenuValidation protocol.

WebKit:

        Reviewed by Beth.

        Fix <rdar://problem/4939672> REGRESSION: With text selected that is
        not a link, the "Remove Link" contextual menu item remains active

        * WebView/WebHTMLView.mm:
        (-[WebHTMLView menuForEvent:]): Leave autoenabling of menu items on so
        that clients can implement validateMenuItem:.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@18975 268f45cc-cd09-0410-ab3c-d52691b4dbfc