For EventLoop, EventLoopBuilder, EventLoopProxy and by requiring it as
a supertrait of Window and ActiveEventLoop.
It is especially useful for user to be able to know that Window is Debug.
* Add cursor position drag and drop events.
* Reword drag events to match pointer ones.
* appkit: Use `convertPoint_fromView` for coordinate conversion.
* appkit: use ProtocolObject<dyn NSDraggingInfo>.
* x11: store dnd.position as pair of i16
It's what translate_coords takes anyway, so the extra precision is
misleading if we're going to cast it to i16 everywhere it's used.
We can also simplify the "unpacking" from the XdndPosition message--we
can and should use the value of 16 as the shift instead of
size_of::<c_short> * 2 or something like that, because the specification
gives us the constant 16.
* x11: store translated DnD coords.
* x11: don't emit DragLeave without DragEnter.
* windows: only emit DragEnter if valid.
* windows: in DnD, always set pdwEffect.
It appears other apps (like Chromium) set pdwEffect on Drop too:
61a391b86b/ui/base/dragdrop/drop_target_win.cc
* docs: make it clearer that drag events are for dragged *files*.
* examples/dnd: handle RedrawRequested event.
Co-authored-by: amrbashir <amr.bashir2015@gmail.com>
