Fix the MiniBrowser build with newer clang

Fix the MiniBrowser build with newer clang

* MiniBrowser/mac/SettingsController.m:
(-[SettingsController _toggleBooleanDefault:]):
* MiniBrowser/mac/WK1BrowserWindowController.m:
(-[WK1BrowserWindowController windowWillClose:]):
* MiniBrowser/mac/WK2BrowserWindowController.m:
(-[WK2BrowserWindowController windowWillClose:]):
NSApp is id and clang gets confused about which -delegate we're talking about.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@180164 268f45cc-cd09-0410-ab3c-d52691b4dbfc