Add a function for QPA plugins to explicitly destroy QScreens

Previously QPlatformScreen was automatically deleting its QScreen
in ~QPlatformScreen(). That means that we cannot use QScreen's
methods when the screen is being removed, because doing so would
call virtual methods of QPlatformScreen. By that point the
QPlatformScreen subclass object does not exist anymore, and we
call the default implementation instead of the subclassed one, or
get a crash for the pure virtual methods. This happens for example
when removing a screen which contains a QWindow with some QML item
using QQuickScreenAttached.

This patch adds a QPlatformIntegration::destroyScreen() function,
which deletes the QScreen and later the QPlatformScreen.

~QPlatformScreen will still delete the QScreen if it was not deleted
with destroyScreen(), so code not ported to the new approach
will continue to work as before, with only a warning added.

Task-number: QTBUG-41141
Change-Id: Ie4a03dee08ceb4c3e94a81875411f6f723273fe1
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Fix build when using -egl and -no-xcb-xlib

Change-Id: I533f1d989b5f4b427ce572620e27c3870a64c2ae
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>
emit lastWindowClosed even if quitOnLastWindowClosed is false

Behavior will agree with the docs.

[ChangeLog][QtGui][QWindow] lastWindowClosed will be emitted even if
quitOnLastWindowClosed is not set

Task-number: QTBUG-32956
Change-Id: I7bb269d53894859fee27e171eea7ad472ea86af0
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>
[QFontDatabasePrivate] Drop unused `fallbackFamilies` member

It is probably a refactoring left-over.

Change-Id: Ic6f1e1a87c8603f600cd1736cf12c03ef0188074
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Re-use cached font engines when request only differs in script

When looking for engine of non-Common script and lookup in
the font cache failed, first check if we have already loaded that engine
for the same request but different script.

In general, this gives an arbitrary font engine a chance to be re-used
multiple times when request only differs in script, which saves a LOT
of memory (~10MB on my win7, after scrolling the QFontComboBox'es list).

Change-Id: I9c752ce65c27142237a0ed74b33742b6a8d90a24
Reviewed-by: Pierre Rossi <pierre.rossi@theqtcompany.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Make it obvious we never expect QFontDatabase::Any to be supported

This also unbreaks matching for scripts not covered
by qt_script_for_writing_system().

Change-Id: Iddf015281a57a9dbae2e09f0408359441b020df8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
QColorDialog: Move string into retranslateStrings()

Change-Id: I802b3e3463f77777cb0f25b60fc069da32d1c467
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>