QtQuick Dialogs: don't use native windows on iOS
QtQuick Dialogs: don't use native windows on iOS

It makes more sense to show the dialogs as items in the scene
rather than as undecorated windows.

Task-number: QTBUG-35561
Change-Id: I2fb29ed8eeb999b99829a9d5ffc088f401d5d602
Reviewed-by: Liang Qi <0f3d3d9587f4f01263b2640b7eef7a92a160ec94@digia.com>

matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,matthewvogt/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,matthewvogt/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,matthewvogt/qtdeclarative