kwin_wayland and setWindowIcon()

[Elvis Angelaccio]

Hi,
kwin_wayland currently sets the application icon only if it can retrieve 
the .desktop filename of the application.

Is there a reason why it doesn't use the icon passed to setWindowIcon() as 
fallback? This seems to work with weston, so I guess it should be possible 
with kwin as well?

I'm asking this because we can't fix all third-party applications. Even 
when we can, sometimes it's just hard to figure out the name of the 
.desktop file. For example, see 
https://codereview.qt-project.org/#/c/205003/1//ALL

Cheers,
Elvis