- Set the software as `initialized` later, and in particular after all
recovered images (from crash) then all command line images were
opened. The reason is that the DBus calls have necessarily been made
after GIMP was started (typically could be images double-clicked
through GUI). We don't want them to appear before the images given in
command line (or worse, some before and some after).
- Process DBus service's data queue as a FIFO. The image requested first
will be loaded first.
- When a DBus call happens while GIMP is not initialized or restored,
switch to a timeout handler. The problem with idle handlers is that
they would be attempted too often (probably even more during startup
when no user event happens). This is good for actions we want to
happen reasonably quickly (like would be normally DBus calls), but not
when we are unsure of program availability schedule (i.e. at startup).
Here not only the handler would run a lot uselessly but it would
likely even slow the startup down by doing so. So while GIMP is not
initialized, switch to half-a-second timeout handler, then only switch
back to idle handler when we are properly initialized and GIMP is
ready to answer calls in a timely manner.
(cherry picked from commit b2649daf11)