Prevent 'recursive' update events when calling QToolButton::setMenu()

Commit bb3d2ca9f18 (QToolButton: properly reset the size hint when a
menu is set on it) didn't take the case of re-setting the same menu
into account, and the result was that we would unconditionally cause
an update, resulting in the following backtrace again and again, as
each posted update event was processed by the event loop:

    frame #0: QToolButton::setMenu(this=0x7af59500, menu=0x00000000)
    frame #1: QToolBarLayout::setUsePopupMenu(this=0x7ae65a30, set=false)
    frame #2: QToolBarLayout::checkUsePopupMenu(this=0x7ae65a30)
    frame #3: QToolBarAreaLayoutLine::fitLayout(this=0x78e5f870)
    frame #4: QToolBarAreaLayoutInfo::fitLayout(this=0x790be278)
    ...

Besides consuming needless CPU time this also uncovered a case on iOS
where Qt would starve native events and animations from being processed,
preventing eg. rotation animations from running.

Change-Id: Ib6bd4ba21d8e84ca73fb0a75b598016dbd9ae0fd
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Avoid sleeping 100ms in QProcessPrivate::drainOutputPipes()

There is no point in waiting 100 milliseconds after each iteration, as
all data that we may possibly read will be already in the pipe. We only
need to give the notifier thread a chance to inform us, which is best
achieved with a yield.

Task-number: QTBUG-41282
Change-Id: Id654b688246508494a5549c11900f9ad2957f192
Reviewed-by: Alessandro Portale <alessandro.portale@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Consolidate how contentDescription is calculated.

Previously, the behavior was different depending on if the
contentDescription was calculated as a result of an event, or if it was
calculated as a result of hierarchy traversal.
Refactor the functionality into one single function that will be used in
both scenarios.

'contentDescription' will now receive its value from one of the following
sources, listed in prioritised order (QAI == QAccessibleInterface):
1. QAI::text(QAccessible::Name)
2. QAI::text(QAccessible::Description)
3. QAI::text(QAccessible::Value)
4. QAI::valueInterface()->currentValue()

Change-Id: I2e4958a1e95b5f20d01da37c23ecbc09842360bc
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>
qdoc: Fixed recursion of \sincelist command handling

QDoc uses a recursive method of resolving all the classes, QML types,
properties, functions etc. added since a specified Qt version.

The code entered the next level of recursion only if its parent had
set a \since version, which was not always the case.

Task-number: QTBUG-41862
Change-Id: I3803ed9ffa472165754358f3906955430a893de1
Reviewed-by: Martin Smith <martin.smith@digia.com>
QTestLib: Remove valgrind version check.

Version 3.3 is now assumed to be widely available.

Task-number: QTBUG-41453
Change-Id: I453ce26d170b2bbb8179ddf4b91155ddd3e6379a
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Jason McDonald <macadder1@gmail.com>
QWindowsGuiEventDispatcher: Register timers in constructor.

Port change 3716a76704273fdbe5ad4ec978438daeda606c26 (Qt 4)
to Qt 5. Enforce the creation of the internal window
and registering of timers in the event dispatcher constructor
for GUI applications instead of delaying it to processEvents()
is called. Move the call to virtual wakeUp() out of
createInternalHwnd().

Task-number: QTBUG-40881
Change-Id: I82a4748897da140a39feff882c75ad5ac6155148
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>