Without selections, drags can't have them either.
Also included is removing the selection from GtkSelectionData.
Includes a bunch of crude cleanups to Wayland code that no longer has to
care about selection atoms.
In the motion compression phase the coalesced events will be saved
as a GdkTimeCoord on the motion event that shall be delivered.
For simplicity (and because history doesn't make much sense otherwise)
event history is only recorded while there are buttons pressed, this
also tidily ensures that those coalesced events would have the same
target widget on the gtk side than the delivered one, because of
implicit grabs.
Two warts remain. gdk_event_copy() should be unnecessary as
events should be considered static after delivery, so g_object_ref()
should be just as good. There's a few exceptional cases that the event
is copied and then modifier for later processing, those cases should be
reconsidered individually.
And gdk_event_free() could be likewise turned into g_object_unref(),
many callers remain though.
Now all events structs are private, it doesn't make as much sense
having GdkEventPrivate wrapping allocating events. This is a first
step towards removing it.
It won't stand true anymore that the GdkEventType argument is the
first field of the GdkEvent* structs. All callers have been updated
to use event->any.type instead.
Instead of just passing the GdkContentFormats, we are now passing the
GdkContentProvider to gdk_drag_begin().
This means that GDK itself can now query the data from the provider
directly instead of having to send selection events.
Use this to provide the private API gdk_drag_context_write() that allows
backends to pass an output stream that this data will be written to.
Implement this as the mechanism for providing drag data on Wayland.
And to make this all work, implement a content provider named
GtkDragContent that is implemented by reverting to the old DND
drag-data-get machinery inside GTK, so for widgets everything works just
like before.
We now have a GdkX11Display::xevent signal that gets emitted for every
XEvent and allows you to interrupt processing via TRUE/FALSE return
values.
These return values to correspond to GDK_FILTER_REMOVE and
GDK_FILTER_CONTINUE respectively.
The GDK_FILTER_TRANSLATE case from gdk_window_add_filter() is now meant
to be handled via gdk_display_put_event().
This is in preparation for DND.
It moves a lot of code from gdkclipboard-x11.c to
gdkselectionoutputstream-x11.c to untangle it from GdkX11Clipboard
usage.
Instead, pass the actions as part of gdk_drag_begin() and insist DND is
always managed.
A new side effect is that gdk_drag_begin() can now return %NULL.
