Created attachment 203864 [details] [review]
The patch, as stated in Gnome Submitting patches. Well commented inside

Here it goes a patch for solving this. It has been talked with the developers, and has implemented in-app notifications.

*** Bug 659746 has been marked as a duplicate of this bug. ***

I commited this patch with some minor changes like:

* Ported to master
* Fixed up whitespace in the files (space at end of lines, etc)
* Fixed a bunch of indentation issues (like space before parantesis, no brackes for one line if, etc
* No need to check twice for _is_hidden_to_delete in is_hidden
* Nicer label in the delete notification

There are still some issues though, that i'd like to clean up:

* We shouldn't be using the Gtk namespace in our app, that is just asking for problem when similar api appears in Gtk.
* The indentation in gtk-notification.c isn't typical gtk+ style
* I think the shadow can be made nicer, for instance there should not be rounded borders at the top, it should go up all the way to the window border
* We don't want to load a custom CSS snippet for the widget, but rather rely on Adwaita and other themes to get our default look
* We want to animate the notifications
* We want to handle stacking of notifications better, they should not cover each other
* "actioned" isn't a great name

*** Bug 666534 has been marked as a duplicate of this bug. ***