...at least with --disable-pch it complained

> [build CXX] canvas/source/directx/dx_bitmapcanvashelper.cxx
> C:/lo/core/include\vcl/vclptr.hxx(98): error C2027: use of undefined type 'OutputDevice'
> c:\lo\core\canvas\source\directx\dx_devicehelper.hxx(33): note: see declaration of 'OutputDevice'
> c:\lo\core\canvas\source\directx\dx_devicehelper.hxx(109): note: see reference to class template instantiation 'VclPtr<OutputDevice>' being compiled

Change-Id: I3ba90acdb632fc209b8137818e30fb771ba0807c