Comment 2 for bug 1621637

This was discussed specific to Files, but might be helpful in other apps as well.

- If displayed text (i.e. folder name) is unique among items in the same tab bar, just show that
- If the folder name is not unique, show the path of the folder up to the point where it’s unique
  - If the folders are `~/Projects/artoo/images/oryp2` and `~/Projects/artoo/videos/oryp2`, show the tab names as `images/oryp2` and `videos/oryp2`.
  - If the folders are `~Projects/artoo/images/oryp2/optimized` and `~/Projects/artoo/videos/oryp2/optimized` , the tabs might show `images/oryp2/optimized` and `videos/oryp2/optimized` respectively.
  - The truncation/ellipsis rules of the HIG should apply; I believe the middle of the tab name should be truncated since the beginning and end of the string are most likely to be unique.
  - This convention puts the unique, distinguishing factors up front while also keeping the standard convention of `/` separation for directories.
- A tooltip should reveal the full path (relative to the home directory if relevant), i.e. `~/Projects/artoo/images/oryp2/optimized` in the previous example.