A single QWindow is QGuiApplication::focusWindow() at a time, and this
window is typically also QWindow::isActive(), but other windows may also
be QWindow::isActive(). For example, we treat any sibling or ancestor
of the focusWindow as being QWindow::isActive() as well.
In addition, in the case of non-QWindow child windows, we may have to
query the platform for the activation state, which means we also need
a way for the platform to reflect changes in this state through QWSI.
The current API for this, QWSI::handleWindowActivated, is in practice
a focus window change API, so as a first step let's rename it to better
reflect what it's doing.
Task-number: QTBUG-119287
Change-Id: I381baf8505dd13a4a829c961095a8d2ed120092b
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
8723daf696