Unreviewed fix build break on EFL port since r149259.

In EFL port, there is a non-compatible code when compiling based on C++11. This is a trivial build fix.

I got a confirm from Sam about landing a trivial build fix patch without sign-off from
WK2 owner.

* UIProcess/API/efl/EwkViewCallbacks.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149267 268f45cc-cd09-0410-ab3c-d52691b4dbfc