Move popup management from QApplication to QGuiApplicationHEADdev

We need to be able to have true popup windows in Qt Quick and Controls,
including handling the press-drag-release sequence to select one entry
from a menu or combobox. After the mouse press, a new window is created.
On some platforms (such as xcb), the new window gets window system grabs
of both keyboard and mouse (QApplicationPrivate::openPopup() calls
grabForPopup() and it actually works); while on others, the pre-existing
window continues to get the whole sequence of mouse events until the
release. In the latter case, Qt needs to forward events from the
original window to the popup. Until now, the list of popups was
QApplicationPrivate::popupWidgets.

Now we track the open popups as a list of QWindows rather than QWidgets,
in QGuiApplicationPrivate::popup_list, and add a set of static functions
to manage that list. Functions such as QApplication::activePopupWidget()
QApplicationPrivate::openPopup() and closePopup() are rewritten to make
requests to QGuiApplicationPrivate.

276943c8b791ba5897dcdb1ecfda780ac33a090b made
QGuiApplicationPrivate::closeAllPopups() virtual. That is now reverted,
because we're putting QGuiApplication in charge of popup management
and trying to minimize widget-specific behavior. So far,
QApplicationPrivate::closePopup() is still overridden to take care
of focus changes.

So far, QtGui does not take care of closing popups when the user
clicks outside: the active popup window gets those events, and needs
to close itself if the click occurs outside. An attempt to move this
logic raised some issues with legacy widget test cases.

Using a touchscreen to press on QMenuBar and open a QMenu, drag to
a menu item and release, is temporarily broken for now. The plan is
to fix it in a subsequent patch.

Task-number: QTBUG-68080
Task-number: QTBUG-69777
Change-Id: I02b5034987b5ee8909917d305f414c8b0db9c7f5
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

0 files changed, 0 insertions, 0 deletions