Full screen mode should not exit when application resigns active state.
https://bugs.webkit.org/show_bug.cgi?id=106129

Reviewed by Darin Adler.

Now that full screen windows get their own full screen space, there is no reason to exit full
screen mode when the application resigns active state. Instead, the windowserver will bring the
space containing the newly active application to the foreground. The user can then swipe back
to the full screen space (or use Mission Control) to get back to the full screen window.

* UIProcess/mac/WKFullScreenWindowController.mm:
(-[WKFullScreenWindowController windowDidLoad]): Remove the applicationDidResignActive: notification from WKFullScreenWindowController.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143982 268f45cc-cd09-0410-ab3c-d52691b4dbfc