| This repository contains hashes of build tools used by Chromium and related | 
 | projects. The actual binaries are pulled from Google Storage, normally as part | 
 | of a gclient hook. | 
 |  | 
 | The repository is separate so that the shared build tools can be shared between | 
 | the various Chromium-related projects without each one needing to maintain | 
 | their own versionining of each binary. | 
 |  | 
 | To update the GN binary, run (from the Chromium repo) tools/gn/bin/roll_gn.py | 
 | which will automatically upload the binaries and roll build tools. | 
 |  | 
 | ________________________________________ | 
 | UPDATING AND ROLLING BUILDTOOLS MANUALLY | 
 |  | 
 | When you update buildtools, you should roll the new version into the Chromium | 
 | repository right away. Otherwise, the next person who makes a change will end | 
 | up rolling (and testing) your change. If there are any unresolved problems with | 
 | your change, the next person will be blocked. | 
 |  | 
 |   - From the buildtools directory, make a branch, edit and upload normally. | 
 |  | 
 |   - Get your change reviewed and landed. There are no trybots so landing will | 
 |     be very fast. | 
 |  | 
 |   - Get the hash for the commit that commit-bot made. Make a new branch in | 
 |     the Chromium repository and paste the hash into the line in //DEPS | 
 |     labeled "buildtools_revision". | 
 |  | 
 |   - You can TBR changes to the DEPS file since the git hashes can't be reviewed | 
 |     in any practical way. Submit that patch to the commit queue. | 
 |  | 
 |   - If this roll identifies a problem with your patch, fix it promptly. If you | 
 |     are unable to fix it promptly, it's best to revert your buildtools patch | 
 |     to avoid blocking other people that want to make changes. | 
 |  | 
 | ________________________ | 
 | ADDING BINARIES MANUALLY | 
 |  | 
 | One uploads new versions of the tools using the 'gsutil' binary from the | 
 | Google Storage SDK: | 
 |  | 
 |   https://developers.google.com/storage/docs/gsutil | 
 |  | 
 | There is a checked-in version of gsutil as part of depot_tools. | 
 |  | 
 | To initialize gsutil's credentials: | 
 |  | 
 |   python ~/depot_tools/third_party/gsutil/gsutil config | 
 |  | 
 |   That will give a URL which you should log into with your web browser. For | 
 |   rolling GN, the username should be the one that is on the ACL for the | 
 |   "chromium-gn" bucket (probably your @google.com address). Contact the build | 
 |   team for help getting access if necessary. | 
 |  | 
 |   Copy the code back to the command line util. Ignore the project ID (it's OK | 
 |   to just leave blank when prompted). |