Chromium docs

This directory contains chromium project documentation in Gitiles-flavored Markdown. It is automatically rendered by Gitiles.

If you add new documents, please also add a link to them in the Document Index below.

Creating Documentation

Guidelines

See the Chromium Documentation Guidelines and the Chromium Documentation Best Practices.
Markdown documents must follow the Markdown Style Guide.

Previewing changes

Locally using md_browser

# in chromium checkout
./tools/md_browser/md_browser.py

This is only an estimate. The gitiles view may differ.

Online with Gerrit's links to gitiles

Upload a patch to gerrit, or receive a review request. e.g. https://chromium-review.googlesource.com/c/3362532
View a specific .md file. e.g. https://chromium-review.googlesource.com/c/3362532/2/docs/README.md
You will see something like
Base preview -> Patchset 3 preview | DOWNLOAD
at the top left of the page. Click on the second “preview” link to open the preview for the current patch set.

This gitiles view is the authoritative view, exactly the same as will be used when committed.

Document Index

Note: this is not an exhaustive list of all documents.

Checking Out and Building

Linux Build Instructions - Linux
Mac Build Instructions - MacOS
Windows Build Instructions - Windows
Android Build Instructions - Android target (on a Linux host)
Cast Build Instructions - Cast target (on a Linux host)
Cast for Android Build Instructions - Cast for Android (on a Linux host)
Fuchsia Build Instructions - Fuchsia target (on a Linux host)
iOS Build Instructions - iOS target (on a MacOS host)
Chrome OS Build Instructions - Chrome OS
Lacros Build Instructions - Lacros
Linux Chromium ARM Recipes - Recipes for building Chromium for ARM on Linux.
Chrome Component Build - Faster builds using more libraries
Using the BuildRunner - Scripts that extract build stops from builders and runs them locally on a slave
Cr User Manual - Manual for cr, a tool that tries to hide some of the tools used for working on Chromium behind an abstraction layer

Design Docs

See design/README.md

Integrated Development Environment (IDE) Set Up Guides

Android Studio - Android Studio for Android builds
Atom - Atom multi-platform code editor
CLion - CLion IDE, supports GUI debugging.
Eclipse for Android - Eclipse for Android
Eclipse for Linux - Eclipse for other platforms (This guide was written for Linux, but is probably usable on Windows/MacOS as well)
EMACS Notes - EMACS commands/styles/tool integrations
Qt Creator - Using Qt Creator as an IDE or GUI debugger
Visual Studio Code - Visual Studio Code

Git

Git Cookbook - A collection of git recipes for common tasks
Git Tips - More git tips
Git submodules - Git submodule (tips, FAQ)

Clang

Clang Compiler - General information on the clang compiler, used by default on Mac and Linux
Clang Tool Refactoring - Leveraging clang tools to perform refactorings that are AST-aware
The Clang Static Analyzer - How to enable static analysis at build time
Clang Code Coverage Wrapper - Enable Clang code coverage instrumentation for a subset of source files.
Writing Clang Plugins - Don't write a clang plugin, but if you do, read this
Updating Clang - Updating the version of Clang used to build
Using clang-format on Chromium C++ Code - Various ways to invoke clang-format on C++ code
Clang Tidy - Support for the clang-tidy tool in Chromium
Updating Clang Format Binaries - How up update the clang-format binaries that come with a checkout of Chromium

General Development

Contributing to Chromium - Reference workflow process for contributing to the Chromium code base.
Commit Checklist - Streamlined checklist to go through before uploading CLs on Gerrit.
Code Reviews - Code review requirements and guidelines
Dependency management - Managing dependencies (DEPS, git submodules)
Respectful Code Reviews - A guide for code reviewers
Respectful Changes - A guide for code authors
Mandatory Code-Review Rollout - Upcoming policy changes related to code review and OWNERS
LUCI Migration FAQ - FAQ on Buildbot-to-LUCI builder migration for Chromium
Tour of Continuous Integration UI - A tour of our the user interface for LUCI, our continuous integration system
Parsing Test Results - An introduction for how to understand the results emitted by polygerrit and CI builds.
Closure Compilation - The Closure JavaScript compiler
Threading and Tasks in Chrome - How to run tasks and handle thread safety in Chrome.
Callback<> and Bind() - All about Callbacks, Closures, and Bind().
Chromium Views UI - Working with the desktop UI framework.
Views Platform Styling - How views are styled to fit in different native platforms
Tab Helpers - Using WebContents/WebContentsObserver to add features to browser tabs.
Adding third_party Libraries - How to get code into third_party/
Graphical Debugging Aid for Chromium Views - Visualizing view trees during debugging
Bitmap Pipeline - How bitmaps are moved from the renderer to the screen.
Flag Guarding Guidelines - When to use server controlled kill switches and A/B experiments to safely roll out changes.
Using the Origin Trials Framework - A framework for conditionally enabling experimental APIs for testing.
Chrome Sync - Docs for the subsystem that allows one to sync data across devices.
Ozone Overview - Ozone is an abstraction layer between the window system and low level input and graphics.
Guidelines for considering branch dates in project planning - What to do (and not to do) around branch dates when scheduling your project work.
WebUI Explainer - An explanation of C++ and JavaScript infrastructural code for Chrome UIs implemented with web technologies (i.e. chrome:// URLs).
Optimizing Chrome Web UIs - Notes on making webuis more performant
Watchlists - Use watchlists to get notified of CLs you are interested in.
Shutdown - Explains the steps of Chrome shutdown, to make it easier to determine where to add a new shutdown operation.
API Keys - When you need access to Google APIs for a custom build, fork, integration of stock Chromium, or are building ChromiumOS (for login).
User Education - Create in-product help (IPH) and tutorials to call out Chromium features

Testing

Running and Debugging Web Tests
On disabling tests
Writing Web Tests - Web Tests using content_shell
Web Test Expectations and Baselines - Setting expected results of web tests.
Web Tests Tips - Best practices for web tests
Web Tests with Manual Fallback - Writing tests that simulate manual interventions
Extending the Web Test Framework
Fixing Web Test Flakiness - Diagnosing and fixing web test flakiness due to ordering dependencies.
Running Web Tests using content_shell - Running web tests by hand.
Web Platform Tests - Shared tests across browser vendors
Using Crashpad with content_shell - Capture stack traces on layout test crashes without an attached debugger
Test Descriptions - Unit test targets that can be built, with associated descriptions.
Fuzz Testing - Fuzz testing in Chromium.
IPC Fuzzer - Fuzz testing of Chromium IPC interfaces.
Running Chrome tests with AddressSanitizer (asan) and LeakSanitizer (lsan) - Run Chrome tests with ASAN and LSAN builds to detect addressability issues and memory leaks.
Code Coverage - Code coverage for Chromium.
Code Coverage in Gerrit - Per-CL code coverage in Gerrit to assist code reviews.