Turns out QWebEngineSettings.globalSettings() only sets things on the default
profile. We now get everything from the default profile settings, but set it on
both the default and the private profile.
Fixes#2638
(cherry picked from commit b11a4388cd10b6ff2fd917fca689ebdc50d581ae)
If we don't wait here, we might end up running the subsequent commands (like
:command-history-prev) on the old window while it's still closing, causing an
exception at least on AppVeyor:
Traceback (most recent call last):
File "C:\projects\qutebrowser\qutebrowser\app.py", line 110, in <lambda>
target_arg=target_arg))
File "C:\projects\qutebrowser\qutebrowser\app.py", line 265, in process_pos_args
win_id = mainwindow.get_window(via_ipc, force_tab=True)
File "C:\projects\qutebrowser\qutebrowser\mainwindow\mainwindow.py", line 89, in get_window
window.setWindowState(window.windowState() & ~Qt.WindowMinimized)
RuntimeError: wrapped C/C++ object of type MainWindow has been deleted
