Reviewed by Adam and Beth.

        Initial cut at pushing Context Menus into WebCore. Nobody actually 
        calls this code just yet.

        * WebCore.exp:
        * WebCore.xcodeproj/project.pbxproj:
        * page/Chrome.cpp:
        (WebCore::Chrome::addCustomContextMenuItems): Use the chrome to 
        call into addContextMenuItems on the UIDelegate.
        * page/Chrome.h:
        * page/ChromeClient.h:
        * platform/ContextMenu.cpp: Added.
        (WebCore::addDefaultItems):
        (WebCore::ContextMenu::populate):
        * platform/ContextMenu.h: Added.
        (WebCore::):
        (WebCore::ContextMenuItem::ContextMenuItem):
        (WebCore::ContextMenu::ContextMenu):
        (WebCore::ContextMenu::hitTestResult):
        (WebCore::ContextMenu::platformMenuDescription):

WebKit:
        Reviewed by Adam & Beth.

        WebKit side of first cut at engine context menus. Use the client to 
        call into the UIDelegate.

        * WebCoreSupport/WebChromeClient.h:
        * WebCoreSupport/WebChromeClient.mm:
        (WebChromeClient::addCustomContextMenuItems):
        * WebKit.xcodeproj/project.pbxproj:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@17796 268f45cc-cd09-0410-ab3c-d52691b4dbfc