[EFL][WK2] Implement runBeforeUnloadConfirmPanel on EFL
https://bugs.webkit.org/show_bug.cgi?id=106979

Patch by Jaehun Lim <ljaehun.lim@samsung.com> on 2013-02-04
Reviewed by Benjamin Poulain.

Implement runBeforeUnloadConfirmPanel() to support window.onbeforeunload.
We can show confirmation window when beforeunload event is fired.

* UIProcess/efl/PageUIClientEfl.cpp:
(WebKit::PageUIClientEfl::PageUIClientEfl):
(WebKit::PageUIClientEfl::runBeforeUnloadConfirmPanel):
(WebKit):
* UIProcess/efl/PageUIClientEfl.h:
(PageUIClientEfl):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141848 268f45cc-cd09-0410-ab3c-d52691b4dbfc