This adds support for download progress reporting via the XApp
method currently used in the Cinnamon desktop, by establishing a new
X11 window property to be supported/read by the window manager.
See https://github.com/linuxmint/xapps/blob/master/libxapp/xapp-gtk-window.c,
as well as https://github.com/linuxmint/muffin/commit/39045da0ea06f
for more details.
The property-setting code lives in nsWindow - it's a small and stable
enough chunk that it made more sense to do this than actually depend on
another external library. As nsWindow is already using x11 calls, this
seemed the safest place for it, without affecting the build.
The TaskbarProgress instance is initialized via the DownloadsTaskbar
js module, and is handed a pointer to the current main window to call
SetProgress on. Most of the javascript side of this is in line with
how the other platforms are handled.
Without a supporting window manager/desktop environment (currently just
Cinnamon/Muffin 3.6,) the simplest way to observe working behavior is
by calling 'xprop -spy' on the browser window being testing and watching
for updates during a download.
--HG--
extra : rebase_source : 0606f6c87116204ec290c19276072d0c1c35691e