Chromium and Chromium OS use a package of scripts called depot_tools to manage checkouts and code reviews.  If you want more details about depot_tools, you can check the depot_tools information page. The depot_tools package includes gclient, gcl, git-cl, repo, and others.

1. Make sure you have the necessary Chromium dependencies set up locally:
   
   
1. On Linux: git is installed by default in normal configurations.
2. On Mac: git is installed and available once Xcode is installed.  See our Mac build instructions for more info on Xcode.
   
   
2. Fetch depot_tools: git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
   
   
3. Add depot_tools to your PATH:

1. $ export PATH="$PATH":`pwd`/depot_tools
2. You may want to add this to your .bashrc file or your shell's equivalent so that you don’t need to reset your $PATH manually each time you open a new shell.

Windows (Cygwin and non-Cygwin)

Preamble

First decide if you want to use cygwin or not. Then, do not switch. If you use native svn on a cygwin's svn checkout and it blows up, you are on your own, e.g. you'll need to do a fresh checkout.

Instructions

1. Get a copy of depot_tools:
• Cygwin: Check out the tools using the command in step (2) for Linux and Mac above.
  New versions of cygwin do not include root certs by default so you need to install a "ca-certificates-1.*-*" package!
• Non-cygwin: Download depot_tools.zip and decompress it. IMPORTANT: DO NOT use drag-n-drop or copy-n-paste extract from Explorer, this will not extract the hidden ".git" folder which is necessary for depot_tools to autoupdate itself. You can use "Extract all..." from the context menu though.
  
2. Add depot_tools to the end (not start!) of your PATH:
• With Administrator access:
• Control Panel > System and Security > System > Advanced system settings
• Modify the PATH system variable to include depot_tools
• Without Administrator access:
• Control Panel > User Accounts > User Accounts > Change my environment variables
• Add a PATH user variable: %PATH%;C:\path\to\depot_tools
3. Non-cygwin: Run gclient from the cmd shell. The first time it is run, it will install its own copy of svn and other tools. If you run gclient from a non-cmd shell, it may appear to run properly, but svn, python, and other tools may not get installed correctly. If you see strange errors with the file system on the first run of gclient, you may want to disable Windows Indexing.  If you see errors like "The system cannot execute the specified program", try installing "Microsoft Visual C++ 2008 Redistributable Package".
4. Cygwin only: Close your shells, reopen a Cygwin shell, and ensure that which svn reports /usr/bin/svn.  If not, you either didn't install the svn package properly when installing Cygwin, or you put depot_tools on the front of your PATH instead of the back.  Fix this before checking out any code, as once you check out, you want to always use the same svn (Cygwin or depot_tools) to work with that checkout -- otherwise strange things can happen that are most easily fixed by completely wiping the checkout.