# Chromium docs This directory contains [chromium project](https://www.chromium.org/Home/) documentation in [Gitiles-flavored Markdown]. It is automatically [rendered by Gitiles]. [Gitiles-flavored Markdown]: https://gerrit.googlesource.com/gitiles/+/master/Documentation/markdown.md [rendered by Gitiles]: https://chromium.googlesource.com/chromium/src/+/main/docs/ **If you add new documents, please also add a link to them in the Document Index below.** [TOC] ## Creating Documentation ### Guidelines * See the [Chromium Documentation Guidelines](documentation_guidelines.md) and the [Chromium Documentation Best Practices](documentation_best_practices.md). * Markdown documents must follow the [style guide](https://github.com/google/styleguide/tree/gh-pages/docguide). ### Previewing changes #### Locally using [md_browser](../tools/md_browser/) ```bash # 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 1. Upload a patch to gerrit, or receive a review request. e.g. https://chromium-review.googlesource.com/c/3362532 2. View a specific .md file. e.g. https://chromium-review.googlesource.com/c/3362532/2/docs/README.md 3. You will see something like
Base [preview](https://chromium.googlesource.com/chromium/src/+/ad44f6081ccc6b92479b12f1eb7e9482f474859d/docs/README.md) -> Patchset 3 [preview](https://chromium.googlesource.com/chromium/src/+/refs/changes/32/3362532/3/docs/README.md) | DOWNLOAD
at the top left of the page. Click on the second "[preview](https://chromium.googlesource.com/chromium/src/+/refs/changes/32/3362532/3/docs/README.md)" 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 ### Checking Out and Building * [Linux Build Instructions](linux/build_instructions.md) - Linux * [Mac Build Instructions](mac_build_instructions.md) - MacOS * [Windows Build Instructions](windows_build_instructions.md) - Windows * [Android Build Instructions](android_build_instructions.md) - Android target (on a Linux host) * [Cast Build Instructions](linux/cast_build_instructions.md) - Cast target (on a Linux host) * [Cast for Android Build Instructions](android_cast_build_instructions.md) - Cast for Android (on a Linux host) * [Fuchsia Build Instructions](fuchsia/build_instructions.md) - Fuchsia target (on a Linux host) * [iOS Build Instructions](ios/build_instructions.md) - iOS target (on a MacOS host) * [Chrome OS Build Instructions](chromeos_build_instructions.md) - Chrome OS * [Linux Chromium ARM Recipes](linux/chromium_arm.md) - Recipes for building Chromium for ARM on Linux. * [Chrome Component Build](component_build.md) - Faster builds using more libraries * [Using the BuildRunner](using_build_runner.md) - Scripts that extract build stops from builders and runs them locally on a slave * [Cr User Manual](cr_user_manual.md) - 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](design/README.md) ### Integrated Development Environment (IDE) Set Up Guides * [Android Studio](android_studio.md) - Android Studio for Android builds * [Atom](atom.md) - Atom multi-platform code editor * [CLion](clion.md) - CLion IDE, supports GUI debugging. * [Eclipse for Android](eclipse.md) - Eclipse for Android * [Eclipse for Linux](linux/eclipse_dev.md) - Eclipse for other platforms (This guide was written for Linux, but is probably usable on Windows/MacOS as well) * [EMACS Notes](emacs.md) - EMACS commands/styles/tool integrations * [Qt Creator](qtcreator.md) - Using Qt Creator as an IDE or GUI debugger * [Visual Studio Code](vscode.md) - Visual Studio Code ### Git * [Git Cookbook](git_cookbook.md) - A collection of git recipes for common tasks * [Git Tips](git_tips.md) - More git tips ### Clang * [Clang Compiler](clang.md) - General information on the clang compiler, used by default on Mac and Linux * [Clang Tool Refactoring](clang_tool_refactoring.md) - Leveraging clang tools to perform refactorings that are AST-aware * [The Clang Static Analyzer](clang_static_analyzer.md) - How to enable static analysis at build time * [Clang Code Coverage Wrapper](clang_code_coverage_wrapper.md) - Enable Clang code coverage instrumentation for a subset of source files. * [Writing Clang Plugins](writing_clang_plugins.md) - Don't write a clang plugin, but if you do, read this * [Updating Clang](updating_clang.md) - Updating the version of Clang used to build * [Using clang-format on Chromium C++ Code](clang_format.md) - Various ways to invoke clang-format on C++ code * [Clang Tidy](clang_tidy.md) - Support for the `clang-tidy` tool in Chromium * [Updating Clang Format Binaries](updating_clang_format_binaries.md) - How up update the clang-format binaries that come with a checkout of Chromium ### General Development * [Contributing to Chromium](contributing.md) - Reference workflow process for contributing to the Chromium code base. * [Commit Checklist](commit_checklist.md) - Streamlined checklist to go through before uploading CLs on Gerrit. * [Code Reviews](code_reviews.md) - Code review requirements and guidelines * [Respectful Code Reviews](cr_respect.md) - A guide for code reviewers * [Respectful Changes](cl_respect.md) - A guide for code authors * [Mandatory Code-Review Rollout](code_review_owners.md) - Upcoming policy changes related to code review and OWNERS * [LUCI Migration FAQ](luci_migration_faq.md) - FAQ on Buildbot-to-LUCI builder migration for Chromium * [Tour of Continuous Integration UI](tour_of_luci_ui.md) - A tour of our the user interface for LUCI, our continuous integration system * [Parsing Test Results](parsing_test_results.md) - An introduction for how to understand the results emitted by polygerrit and CI builds. * [Closure Compilation](closure_compilation.md) - The _Closure_ JavaScript compiler * [Threading and Tasks in Chrome](threading_and_tasks.md) - How to run tasks and handle thread safety in Chrome. * [Callback<> and Bind()](callback.md) - All about Callbacks, Closures, and Bind(). * [Chromium Views UI](ui/index.md) - Working with the desktop UI framework. * [Views Platform Styling](ui/views/platform_style.md) - How views are styled to fit in different native platforms * [Tab Helpers](tab_helpers.md) - Using WebContents/WebContentsObserver to add features to browser tabs. * [Adding third_party Libraries](adding_to_third_party.md) - How to get code into third_party/ * [Graphical Debugging Aid for Chromium Views](graphical_debugging_aid_chromium_views.md) - Visualizing view trees during debugging * [Bitmap Pipeline](bitmap_pipeline.md) - How bitmaps are moved from the renderer to the screen. * [Using the Origin Trials Framework](origin_trials_integration.md) - A framework for conditionally enabling experimental APIs for testing. * [Chrome Sync](https://source.chromium.org/chromium/chromium/src/+/main:docs/website/site/developers/design-documents/sync) - Docs for the subsystem that allows one to sync data across devices. * [Ozone Overview](ozone_overview.md) - Ozone is an abstraction layer between the window system and low level input and graphics. * [Optimizing Chrome Web UIs](optimizing_web_uis.md) - Notes on making webuis more performant * [Adding a new feature flag in chrome://flags](how_to_add_your_feature_flag.md) - Quick guide to add a new feature flag to experiment your feature. * [Guidelines for considering branch dates in project planning](release_branch_guidance.md) - What to do (and not to do) around branch dates when scheduling your project work. * [WebUI Explainer](webui_explainer.md) - An explanation of C++ and JavaScript infrastructural code for Chrome UIs implemented with web technologies (i.e. chrome:// URLs). * [Watchlists](infra/watchlists.md) - Use watchlists to get notified of CLs you are interested in. * [Shutdown](shutdown.md) - Explains the steps of Chrome shutdown, to make it easier to determine where to add a new shutdown operation. * [API Keys](api_keys.md) - When you need access to Google APIs for a custom build, fork, integration of stock Chromium, or are building ChromiumOS (for login). ### Testing * [Running and Debugging Web Tests](testing/web_tests.md) * [On disabling tests](testing/on_disabling_tests.md) * [Writing Web Tests](testing/writing_web_tests.md) - Web Tests using `content_shell` * [Web Test Expectations and Baselines](testing/web_test_expectations.md) - Setting expected results of web tests. * [Web Tests Tips](testing/web_tests_tips.md) - Best practices for web tests * [Web Tests with Manual Fallback](testing/web_tests_with_manual_fallback.md) - Writing tests that simulate manual interventions * [Extending the Web Test Framework](how_to_extend_web_test_framework.md) * [Fixing Web Test Flakiness](testing/identifying_tests_that_depend_on_order.md) - Diagnosing and fixing web test flakiness due to ordering dependencies. * [Running Web Tests using `content_shell`](testing/web_tests_in_content_shell.md) - Running web tests by hand. * [Web Platform Tests](testing/web_platform_tests.md) - Shared tests across browser vendors * [Using Crashpad with `content_shell`](testing/using_crashpad_with_content_shell.md) - Capture stack traces on layout test crashes without an attached debugger * [Test Descriptions](testing/test_descriptions.md) - Unit test targets that can be built, with associated descriptions. * [Fuzz Testing](../testing/libfuzzer/README.md) - Fuzz testing in Chromium. * [IPC Fuzzer](testing/ipc_fuzzer.md) - Fuzz testing of Chromium IPC interfaces. * [Running Chrome tests with AddressSanitizer (asan) and LeakSanitizer (lsan)](testing/linux_running_asan_tests.md) - Run Chrome tests with ASAN and LSAN builds to detect addressability issues and memory leaks. * [Code Coverage](testing/code_coverage.md) - Code coverage for Chromium. * [Code Coverage in Gerrit](testing/code_coverage_in_gerrit.md) - Per-CL code coverage in Gerrit to assist code reviews. ### GPU-related docs * [GPU Pixel Wrangling](gpu/pixel_wrangling.md) - Instructions for GPU pixel wrangling (the GPU sheriffing rotation). * [Debugging GPU related code](gpu/debugging_gpu_related_code.md) - Hints for debugging GPU- and graphics-related code. * [GPU Testing](gpu/gpu_testing.md) - Description of Chromium's GPU testing infrastructure. * [GPU Bot Details](gpu/gpu_testing_bot_details.md) - In-depth description of how the bots are maintained. ### Misc Linux-Specific Docs * [Linux Proxy Config](linux/proxy_config.md) - Network proxy sources on Linux * [Debugging SSL on Linux](linux/debugging_ssl.md) - Tips on debugging SSL code in Linux * [Linux Cert Management](linux/cert_management.md) - Managing X.509 Certificates in Linux * [Tips for Debugging on Linux](linux/debugging.md) * [Linux GTK Theme Integration](linux/gtk_theme_integration.md) - Having Chrome match the GTK+ theme. * [Browser Plugins on Linux](linux/plugins.md) - A collection of links to information on how browser plugins work on Linux * [Linux Crash Dumping](linux/crash_dumping.md) - How Breakpad uploads crash reports to Google crash servers. * [Linux Minidump to Core](linux/minidump_to_core.md) - How to convert a Breakpad-generated minidump files to a core file readable by most debuggersx * [Linux Sandbox IPC](linux/sandbox_ipc.md) - The lower level UPC system used to route requests from the bottom of the call stack up into the browser. * [Linux Dev Build as Default Browser](linux/dev_build_as_default_browser.md) - How to configure a Dev build of Chrome as the default browser in Linux. * [Linux Chromium Packages](linux/chromium_packages.md) - Packages of Chromium browser (not Chrome) provided by some Linux distributions. * [`seccomp` Sandbox Crash Dumping](seccomp_sandbox_crash_dumping.md) - Notes on crash dumping a process running in a seccomp sandbox. * [Linux Password Storage](linux/password_storage.md) - Keychain integrations between Chromium and Linux. * [Linux Sublime Development](sublime_ide.md) - Using Sublime as an IDE for Chromium development on Linux. * [Building and Debugging GTK](linux/building_debug_gtk.md) - Building Chromium against GTK using lower optimization levels and/or more debugging symbols. * [Debugging GTK](linux/debugging_gtk.md) - Using the GTK Debug packages and related tools. * [Chroot Notes](linux/using_a_chroot.md) - Setting up a chroot to work around libfreetype differences in some versions of Linux. * [Linux Sandboxing](linux/sandboxing.md) - The Linux multi-process model to isolate browser components with different privileges. * [Zygote Process](linux/zygote.md) - How the Linux Zygote process, used to spawn new processes, works. * [Running Web Tests on Linux](testing/web_tests_linux.md) - Linux-specific instructions for running web tests. * [Linux Sysroot Images](linux/sysroot.md) - How builds use libraries on Linux * [Linux Hardware Video Decoding](linux/hw_video_decode.md) - Enabling hardware video decode codepaths on Linux ### Misc MacOS-Specific Docs * [Mac Debugging Tips](mac/debugging.md) - An introduction to debugging on Mac, as well as a collection of useful tips. * [Using CCache on Mac](ccache_mac.md) - Speed up builds on Mac using ccache with clang/ninja * [Cocoa tips and tricks](cocoa_tips_and_tricks.md) - A collection of idioms used when writing Cocoa views and controllers * [MacViews Release Plan](ui/views/macviews_release.md) ### Misc Windows-Specific Docs * [Handling cygwin rebaseall failures](cygwin_dll_remapping_failure.md) * [Hacking on ANGLE in Chromium](angle_in_chromium.md) - OpenGL ES 2.0 built on top of DirectX * [Windows Split DLLs](windows_split_dll.md) - Splitting `chrome.dll` into multiple dlls to work around toolchain limitations on Windows. * [Windows Native Window Occlusion Tracking](windows_native_window_occlusion_tracking.md) * [Windows PWA Integration](windows_pwa_integration.md) - Integration with Progressive Web Apps on Windows * [Windows Shortcut and Taskbar Handling](windows_shortcut_and_taskbar_handling.md) * [Windows Virtual Desktop Integration](windows_virtual_desktop_handling.md) ### Misc Android-Specific Docs * [Google Play Services in Chrome for Android](google_play_services.md) * [Accessing C++ Enums in Java](android_accessing_cpp_enums_in_java.md) - How to use C++-defined enums in Java code * [Profiling Content Shell on Android](profiling_content_shell_on_android.md) - Setting up profiling for `content_shell` on Android * [Working Remotely with Android](working_remotely_with_android.md) - Building on a remote machine for an Android device connected to your local machine * [Android Test Instructions](testing/android_test_instructions.md) - Running a build on an Android device or emulator. * [Android Debugging](android_debugging_instructions.md) - Tools and tips for how to debug Java and/or C/C++ code running on Android. * [Android Logging](android_logging.md) - How Chrome's logging API works with `android.util.Log` on Android, and usage guidelines. * [Android Java Static Analysis](../build/android/docs/lint.md) - Catching Java related issues at compile time with the 'lint' tool. * [Java Code Coverage](../build/android/docs/coverage.md) - Collecting code coverage data with the EMMA tool. * [Dynamic Feature Modules (DFMs)](android_dynamic_feature_modules.md) - What are they and how to create new ones. * [Other build-related Android docs](../build/android/docs/index.md) * [Chrome for Android UI](ui/android/overview.md) - Resources and best practices for developing UI ### Misc iOS-Specific Docs * [Continuous Build and Test Infrastructure for Chromium for iOS](ios/infra.md) * [Opening links in Chrome for iOS](ios/opening_links.md) - How to have your iOS app open links in Chrome. * [User Agent in Chrome for iOS](ios/user_agent.md) - Notes on User Agent strings using Chrome for iOS. * [Running iOS test suites locally](ios/testing.md) * [Working With Project Files in iOS](ios/working_with_files.md) - How to add, remove, and rename files in the iOS Chromium project. ### Misc Chrome-OS-Specific Docs * [Setting up captive portals and other restrictive networks](login/restrictive_networks.md) * [Enterprise Enrollment](enterprise/enrollment.md) * [Kiosk mode and public sessions](enterprise/kiosk_public_session.md) * [Debugging UI in OOBE/login/lock](login/ui_debugging.md) * [Chrome Logging on Chrome OS](chrome_os_logging.md) * [Debugging tips](testing/chromeos_debugging_tips.md) ### Misc WebUI-Specific Docs * [Creating WebUI Interfaces in components/](webui_in_components.md) How to create a new WebUI component in the `components/` directory. * [Trusted Types on WebUI](trusted_types_on_webui.md) Tips for coding in WebUI with Trusted Types in mind. ### Media * [Audio Focus Handling](media/audio_focus.md) - How multiple MediaSession audio streams interact * [Autoplay of HTMLMediaElements](media/autoplay.md) - How HTMLMediaElements are autoplayed. * [Piranha Plant](piranha_plant.md) - Future architecture of MediaStreams * [Video Encode Accelerator Tests](media/gpu/veatest_usage.md) - How to use the accelerated video encoder test program. * [Video Decoder Tests](media/gpu/video_decoder_test_usage.md) - Running the video decoder tests. * [Video Decoder Performance Tests](media/gpu/video_decoder_perf_test_usage.md) - Running the video decoder performance tests. ### Accessibility * [Accessibility Overview](accessibility/overview.md) - Overview of accessibility concerns and approaches in Chromium. * [Accessibility Tests](accessibility/browser/tests.md) - Where to find accessibility-related tests in the codebase. * [ChromeVox on Chrome OS](accessibility/os/chromevox.md) - Enabling spoken feedback (ChromeVox) on Chrome OS. * [ChromeVox on Desktop Linux](accessibility/os/chromevox_on_desktop_linux.md) - Enabling spoken feedback (ChromeVox) on desktop Linux. * [Offscreen, Invisible and Size](accessibility/browser/offscreen.md) - How Chrome defines offscreen, invisible and size in the accessibility tree. * [Text to Speech](accessibility/browser/tts.md) - Overview of text to speech in Chrome and Chrome OS. * [BRLTTY in Chrome OS](accessibility/os/brltty.md) - Chrome OS integration with BRLTTY to support refreshable braille displays * [PATTS on Chrome OS](accessibility/os/patts.md) - Notes on the PATTS speech synthesis engine used on Chrome OS * [VoiceOver](ios/voiceover.md) - Using Apple's VoiceOver feature with Chromium on iOS. ### Memory * [Memory Overview](memory/README.md) ### Memory Infrastructure Timeline Profiling (MemoryInfra) * [Overview](memory-infra/README.md) * [GPU Profiling](memory-infra/probe-gpu.md) * [Adding Tracing to a Component](memory-infra/adding_memory_infra_tracing.md) * [Enabling Startup Tracing](memory-infra/memory_infra_startup_tracing.md) * [Memory Usage in CC](memory-infra/probe-cc.md) * [Memory Benchmarks](memory-infra/memory_benchmarks.md) * [Heap Profiling](memory-infra/heap_profiler.md) ### Metrics * [Histograms](/tools/metrics/histograms/README.md) * [User Actions](/tools/metrics/actions/README.md) * [Code review guidelines](/tools/metrics/histograms/review_guidelines.md) ### Misc * [Useful URLs](useful_urls.md) - A collection of links to various tools and dashboards * [ERC IRC](erc_irc.md) - Using ERC in EMACS to access IRC * [Kiosk Mode](kiosk_mode.md) - Simulating kiosk mode. * [User Handle Mapping](user_handle_mapping.md) - Names of developers across Chromium/IRC/Google * [Documentation Best Practices](documentation_best_practices.md) * [Documentation Guidelines](documentation_guidelines.md) * [Chromium Browser vs Google Chrome](chromium_browser_vs_google_chrome.md) - What's the difference between _Chromium Browser_ and _Google Chrome_? * [Google Chrome branded builds](google_chrome_branded_builds.md) * [Proxy Auto Config using WPAD](proxy_auto_config.md) - How WPAD servers are used to automatically set proxy settings. * [Installing Chromium OS on VMWare](installation_at_vmware.md) - How to install Chromium OS on VMWare. * [User Data Directory](user_data_dir.md) - How the user data and cache directories are determined on all platforms. * [User Data Storage](user_data_storage.md) - Policy documentation for files in User Data. ### Mojo & Services * [Intro to Mojo & Services](mojo_and_services.md) - Quick introduction to Mojo and services in Chromium, with examples * [Mojo API Reference](/mojo/README.md) - Detailed reference documentation for all things Mojo * [Service Development Guidelines](/services/README.md) - Guidelines for service development in the Chromium tree * [Servicifying Chromium Features](servicification.md) - General advice for integrating new and existing subsystems into Chromium as services * [Converting Legacy IPC to Mojo](mojo_ipc_conversion.md) - Tips and common patterns for practical IPC conversion work * [Mojo “Style” Guide](security/mojo.md) - Recommendations for best practices from Mojo and IPC reviewers * [D-Bus Mojo Connection Service](dbus_mojo_connection_service.md) - A service in Chrome to bootstrap CrOS services' Mojo connection. ### Speed * [Chrome Speed](speed/README.md) - Documentation for performance measurements and regressions in Chrome. * [Chrome Speed Metrics](speed_metrics/README.md) - Documentation about user experience metrics on the web and their JavaScript APIs. ### Probably Obsolete * [TPM Quick Reference](tpm_quick_ref.md) - Trusted Platform Module notes. * [System Hardening Features](system_hardening_features.md) - A list of current and planned Chrome OS security features. * [WebView Policies](webview_policies.md) * [Linux Profiling](linux/profiling.md) - How to profile Chromium on Linux * [Linux Graphics Pipeline](linux/graphics_pipeline.md) * [Linux `SUID` Sandbox](linux/suid_sandbox.md) - Sandboxing renderers using a SUID binary on Linux * [Linux `SUID` Sandbox Development](linux/suid_sandbox_development.md) - Development on the above system. * [Linux PID Namespace Support](linux/pid_namespace_support.md) * [Vanilla msysgit workflow](vanilla_msysgit_workflow.md) - A workflow for using mostly vanilla git on Windows. * [Old Options](chrome_settings.md) - Pre-Material Design chrome://settings notes.