[enhancemement] [docs] How to write a a Mir backend for a shell

[Daniel Holbach]

Feedback from Daniel van Vugt:
 - Backend for a "window manager": This means a shell, linking to libmirserver.
 - Class structure (via libmirserver) maybe not quite right to go documenting this yet.
 - you can look at examples/demo-shell/* which is intended to be a totally generic
   shell with no links to Unity. It still needs more functionality yet, though.

We could link to this example more prominently on the main page to start this effort.

Is the class structure definition tracked somewhere else?

[Daniel van Vugt (vanvugt)]

This task should be deferred. Because the instructions will change significantly as we build and learn from writing our own initial Mir shells. The API is changing as much as the shells themselves right now.

[Daniel Holbach (dholbach)]

Maybe for now we could post some preliminary information. Like a disclaimer that things are moving quickly right now, but point to the IRC channel, the mailing list and which pieces of code to look at to get an idea of what's involved.

[Robert Ancell (robert-ancell)]

I've filed bug 1193933 to split out the request for toolkit documentation - shells and toolkit are completely different cases.

[Daniel Holbach (dholbach)]

Do we have code examples we could link to already? What are the concepts we need to explain here?

[Michał Sawicz (saviq)]

Syncing task from Mir.