[GTK] Do not use GtkWindow:resize-grip-visible with recent GTK+ versions
https://bugs.webkit.org/show_bug.cgi?id=135699

Reviewed by Philippe Normand.

Resize grips support have been removed from GTK+ since 3.13.4, the
API has been deprecated and does nothing.

* UIProcess/API/gtk/WebKitWebViewBase.cpp:
(webkitWebViewBaseSetToplevelOnScreenWindow):
(resizeWebKitWebViewBaseFromAllocation):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@172341 268f45cc-cd09-0410-ab3c-d52691b4dbfc