...complaining that "defaulted move assignment for ‘cppcanvas::SpriteCanvas’ calls a non-trivial move assignment operator for virtual base ‘cppcanvas::BitmapCanvas’." Change-Id: I4dc92176dbec62f0ae4fa7d2842073077ecb8fc3
Helper C++ classes for [[canvas]], plus a GDIMetaFile-to-XCanvas converter.