Fix for https://bugs.webkit.org/show_bug.cgi?id=56068

Fix for https://bugs.webkit.org/show_bug.cgi?id=56068
<rdar://problem/9058245> WebKit2: Can't uncheck 'Spelling and Grammar' contextual items

Reviewed by Anders Carlsson.

* UIProcess/WebPageProxy.cpp: (WebKit::WebPageProxy::contextMenuItemSelected):
Add cases for ContextMenuItemTagCorrectSpellingAutomatically, ContextMenuItemTagCheckSpellingWhileTyping,
and ContextMenuItemTagCheckGrammarWithSpelling

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@80683 268f45cc-cd09-0410-ab3c-d52691b4dbfc