Before we can use your code, you must sign the [Google Individual Contributor License Agreement] (https://cla.developers.google.com/about/google-individual) (CLA), which you can do online. The CLA is necessary mainly because you own the copyright to your changes, even after your contribution becomes part of our codebase, so we need your permission to use and distribute your code. We also need to be sure of various other things—for instance that you'll tell us if you know that your code infringes on other people's patents. You don't have to sign the CLA until after you've submitted your code for review and a member has approved it, but you must do it before we can put your code into our codebase.
Contributions made by corporations are covered by a different agreement than the one above, the [Software Grant and Corporate Contributor License Agreement] (https://cla.developers.google.com/about/google-corporate).
For all contributors, we recommend the standard GitHub flow based on forking and pull requests.
For significant changes, please create an issue to let everyone know what you're planning to work on, and to track progress and design decisions.