I think that it would be useful to have an `ArcanistLogWorkflow` which provides a `arc log` command. I would expect the command to provide similar output to `git log --oneline`, but showing information relevant to Phabricator.
**Example output**
```
> arc log
Commit Differential Message
0d0b8ab D9263 set custom arcrc file earlier
1782044 D9269 Change double quotes to single quotes.
e34bdf6 D9271 Fix diffusion.looksoon call to actually work
042aa2e D9246 Add an `ArcanistGoLintLinter`.
85b8b2e D9246 Make `arc shell-complete` more robust.
```