atom/atom — pull request #3171 by dmnd (2014-08-04 00:20:26+00:00)
Title: Add OS X proxy icon to title bar

![image](https://cloud.githubusercontent.com/assets/4427/3792226/15dc419a-1b6d-11e4-856b-a6a87be9b3fa.png)

Fixes #1891.

Test Plan:

* Opened Atom window in directory, verified directory icon shows up
* Opened a file and verified icon changed
* Right clicked icon, verified menu appears
* Drag file to terminal and it pastes the file path (yay)
* Opened a new Atom window and opened some files in that to make sure that
it didn't change the original window

I didn't add any specs for this - advice welcome here. I also haven't tested
on Windows or Linux but it looks like `setRepresentedFilename` is a noop on
those platforms.