Font Database: Add support for private, system UI font families

We introduce QPlatformFontDatabase::isPrivateFontFamily() to allow
testing for private, system UI font families. Both QFontComboBox
and QFontDialog need to filter out those private font families
which, by definition, should be hidden from the end user.

(The textedit example had to be updated to fix the issue where the
default font would be private. In 5.4, we will be adding an equivalent,
public API in QFontDatabase, and a better solution for the textedit
example and QTexEdit in general).

In particular, on OS X and iOS, private fonts are used for the system
UI font. Those have their font family name prefixed by a dot.
QCoreTextFontDatabase knows about this, and makes sure those are
tested positive as private font families. In order to have a cleaner
layer separation, we moved the QPA theme font resolution from the
platform theme classes into QCoreTextFontDatabase for both Cocoa and
iOS QPA plugins.

In both cases, we use CoreText's CTFontCreateUIFontForLanguage(), that
nicely maps to the HITheme API we were using so far on Mac. That means
one HITheme dependency less. We also cache the font descriptors we get
for these font for each time QCTFD::populateFamilies() gets called.
(While not common, this currently happens in auto-tests, like
tst_QFontDatabase, and could happen in actual applications -- specially
when adding and removing application fonts.)

Change-Id: Ic6f0b60f9f597afee1a43596a669742dc546b97f
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Fix build with QT_NO_DRAGANDDROP

viewportSizeHint() should be defined outside the QT_NO_DRAGANDDROP ifndef

Change-Id: I7c23c820ea58b3614eb030dc5b0f290ad891ccb1
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Fix build due to missing include when using a minimal config.

QStyle is used, so include it explicitly instead of relying on
indirect inclusions.

Build was broken when using a bunch of QT_NO_ defines, not sure
which one triggers the failure though.

Change-Id: Ib07218521648448576f1b55d2d91d1711c048f09
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Fix rendering alpha-blended text which needs to be clipped at the top.

Task-number: QTBUG-34148
Change-Id: I9c0694e67cc9883db318c1a1558bdf6e08088db4
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Doc: document that we have unfixed bugs with waitForXxx on Windows

We have to document because we don't know how to fix the bug and don't
know when they will be fixed. We should also disable the unit tests
related to those functions, as they probably cause CI instability.

Task-number: QTBUG-24451
Change-Id: I0e60682ec4af7570258b13735339051ba8f4a6e4
Reviewed-by: David Faure <david.faure@kdab.com>
Reviewed-by: Richard J. Moore <rich@kde.org>
Fix disconnect()ing from signals declared in a base class

Fix disconnection from pointer to member signal that belongs to the base
class, but whose type is a pointer to a member of the derived class.

Commit 9cc106d9d7d951fcf30f4b0f8606afa6b50892ec fixed connect, so apply
the same fix in disconnect

[ChangeLog][QtCore][QObject] Fixed disconnecting from pointer to member
signal that belongs in the base class but whose type is explicitly given
as a pointer to a member in the derived class

Task-number: QTBUG-40638
Change-Id: Ia546fc8f36e1ea0dd0645bdd820aea47f43677ac
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>