tree 7bb1cd37b7ddfaef6338866310cdce17d407eb2c
parent f4a3bb737a281554a9241f4a8289e2d2564cee83
author Joshua Seaton <joshuaseaton@google.com> 1573089720 -0800
committer Joshua Seaton <joshuaseaton@google.com> 1573253093 -0800

Update Root.UniqueKeys() to index by particular role

* We originally added this method - and have no known uses currently in
the tree.
* The updated logic is convenient, as it is a common calculation to find
the unique root keys corresponding to the "root" role alone.

Test: repo_tests were updated - and pass.

Change-Id: If2e74187d13eb85d965c843bdf4296b2c76b046a