We load a WebDocument with an unknown size the same way as we load
normal photos with FileLocation, that doesn't contain size as well.
If the size information from WebDocument and upload.WebFile is
inconsistent we still fail to load the file.
Currently the build without implicitly included precompiled header
is not supported anyway (because Qt MOC source files do not include
stdafx.h, they include plain headers).
So when we decide to support building without implicitly included
precompiled headers we'll have to fix all the headers anyway.
John Preston