|  | Want to contribute? Great! First, read this page (including the small print at | 
|  | the end). | 
|  |  | 
|  | ### Before you contribute | 
|  | 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. | 
|  |  | 
|  | Before you start working on a larger contribution, you should get in touch with | 
|  | us first through the issue tracker with your idea so that we can help out and | 
|  | possibly guide you. Coordinating up front makes it much easier to avoid | 
|  | frustration later on. | 
|  |  | 
|  | ### Code reviews | 
|  | All submissions, including submissions by project members, require review. | 
|  |  | 
|  | ### File headers | 
|  | All files in the project must start with the following header. | 
|  |  | 
|  | // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file | 
|  | // for details. All rights reserved. Use of this source code is governed by a | 
|  | // BSD-style license that can be found in the LICENSE file. | 
|  |  | 
|  | ### The small print | 
|  | Contributions made by corporations are covered by a different agreement than the | 
|  | one above, the | 
|  | [Software Grant and Corporate Contributor License Agreement](https://developers.google.com/open-source/cla/corporate). |