The new QPageLayout methods weren't originally added to QPagePaintDevice
as no new virtuals can be added, instead static polymorphism was used to
add the methods directly in the derived classes QPdfWriter and QPrinter.
This however means that classes like QTextDocument with print() methods
that take a QPagedPaintDevice are unable to access the QPageLayout
methods. To fix this, instead make the QPagedPaintDevicePrivate a
virtual class and have QPdfWriter and QPrinter implement derived
private classes that are called by the non-virtual QPagedPaintDevice
base methods.
Change-Id: Ieb6e513b1fa05f5ae76ea1f9156b0b1a053089eb
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
bc46b591b2