Chromium uses a package of scripts, the depot_tools, to manage interaction with the Chromium source code repository and the Chromium development process. It contains the following utilities:
gclient: Meta-checkout tool managing both subversion and git checkouts. It is similar to repo tool except that it works on linux, mac and windows and supports both svn and git. On the other hand, gclient doesn't integrate any code review functionality.
gcl: Rietveld code review tool for subversion. The gcl tool runs presubmit scripts.
git-cl: Rietveld code review tool for git. The git-cl tool runs presubmit scripts.
hammer: (Obsolete) Wrapper script for building Chromium with the SCons software construction tool.