The doc at http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/git-drover.html mentions you should use `gclient sync --with_branch_heads` but that didn't work for me until I also called `git fetch --tags` as mentioned at https://www.chromium.org/developers/how-tos/get-the-code/working-with-release-branches. It would probably be helpful to include that in the drover page too.