Pretty happy with cloud9 myself, I use the free plan for web development and besides the storage limitations (when using METEOR) I've been very happy with it!

If you have Developer Mode on your chromebook you can get to the Crosh shell with Ctrl+Alt+T, which will let you open a full bash shell if you have rights. From there you can just ssh into a server and develop directly on the "cloud".

If you're not comfortable with vi/emacs for this, then I'd suggest going with Cloud 9, because you can hook it to your github account and get stuff synched very easily. 

If you're doing hardware specifically, there is a tool called MBED, that ARM makes, that is specifically a cloud IDE for developing on hardware, mostly those intended to be networked or wireless, but it'll flash a lot of different stuff, direct from your chromebook, which is pretty cool. But it is limited in some ways, and depends on the platform you are developing for being supported, or you doing a lot of custom nonsense to make your board work. 

I use ipython-notebook for much of my development because there are a number of ways to deploy it. I've recently run across an article discussing working directly from github repos with Binder. Perhaps this would be helpful: http://mybinder.org/

Good luck!

I should precise that I'm more of a hardware guy so I'm not looking for something ultra complex. Just enough to code some python or C for my projects and sync it with Github.