MonthGrid: fix dates being incorrect for certain timezonesHEADdev

When a QDate is passed to QML, it becomes to a JavaScript Date.
As Dates are stored in local time, the QDates we were passing to
QML had the potential to be one day off in certain timezones.
For example: 00:00 UTC converted to UTC-8 is 20:00 the day before.

Fix this by storing and providing dates as QDateTime so that we can
give it a time of day that can't possibly result in a different day
when converted to local time. It's fine to change the C++ API since
it's private, and nothing will change for the type that users see,
since they always get a Date.

Add a SystemEnvironment singleton to QQuickControlsTestUtils
(Qt.test.controls) to allow reading and writing environment
variables from QML.

Fixes: QTBUG-72208
Pick-to: 6.8 6.9 6.10
Change-Id: Idb4ab26568d8f1eddd5ab4cebe691e38173d02a9
Reviewed-by: Ulf Hermann <[email protected]>

0 files changed, 0 insertions, 0 deletions