https://bugs.webkit.org/show_bug.cgi?id=50586
        
Reviewed by John Sullivan.

WebCore: 

ContextMenuMac.mm had a WebCoreMenuTarget class, which was responsible for wrapping
a ContextMenuItem, and calling through to the ContextMenuController to validate it
and call a function when it was selected.
        
It was a layering violation to have this class here, because ContextMenu can't know
about ContextMenuController.
        
This patch moves the class that wraps the ContextMenuItems to WebKit/mac/WebHTMLView.mm,
and sets up the menu targets there.

No change in behavior, no new tests.

* WebCore.exp.in: Added function that needs to be exported.
* platform/mac/ContextMenuMac.mm:
(WebCore::ContextMenu::ContextMenu): Don't set the sharedMenuTarget anymore.
(WebCore::ContextMenu::appendItem): Don't call setMenuItemTarget (this is done in WebKit now).
(WebCore::ContextMenu::insertItem): Ditto.

WebKit/mac: 

Move WebMenuTarget from ContextMenuMac to here, because having it in ContextMenuMac
was a layering violation. Also, make sure we set the menu item targets for all menu
items before showing them, because the ContextMenu constructor doesn't do that anymore.

* WebView/WebHTMLView.mm:
(+[WebMenuTarget sharedMenuTarget]): Moved from ContextMenuMac.mm.
(-[WebMenuTarget WebCore::]): Ditto.
(-[WebMenuTarget setMenuController:WebCore::]): Ditto.
(-[WebMenuTarget forwardContextMenuAction:]): Ditto.
(-[WebMenuTarget validateMenuItem:]): Ditto.

(setMenuItemTarget): Sets the target of the NSMenuItem to the shared WebMenuTarget.
(setMenuTargets): Recursively iterates over all NSMenuItems in an NSMenu (including
    submenus), and calls setMenuItemTarget on them.
(-[WebHTMLView menuForEvent:]): Call setMenuTarget on all the menu items before adding
    them to the menu.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@73469 268f45cc-cd09-0410-ab3c-d52691b4dbfc