[GTK] Invalid charset encoding using when substituting a misspelled word in WebKit2
https://bugs.webkit.org/show_bug.cgi?id=112517

Patch by Carlos Garcia Campos <cgarcia@igalia.com> on 2013-03-17
Reviewed by Alexey Proskuryakov.

The problem is that we are creating the WebContextMenuItemData
with the GtkAction label as UTF-8.

* UIProcess/gtk/WebContextMenuProxyGtk.cpp:
(WebKit::contextMenuItemActivatedCallback): Use String::fromUTF8()
to convert the GtkAction label to UTF-16.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146011 268f45cc-cd09-0410-ab3c-d52691b4dbfc