There are instructions for other platforms linked from the get the code page.
Are you a Google employee? See go/building-android-chrome instead.
Most development is done on Ubuntu. Other distros may or may not work; see the Linux instructions for some suggestions.
Building the Android client on Windows or Mac is not supported and doesn't work.
Clone the depot_tools
repository:
git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
Add depot_tools
to the end of your PATH (you will probably want to put this in your ~/.bashrc
or ~/.zshrc
). Assuming you cloned depot_tools
to /path/to/depot_tools
:
export PATH="$PATH:/path/to/depot_tools"
Create a chromium
directory for the checkout and change to it (you can call this whatever you like and put it wherever you like, as long as the full path has no spaces):
mkdir ~/chromium && cd ~/chromium fetch --nohooks android
If you don't want the full repo history, you can save a lot of time by adding the --no-history
flag to fetch
.
Expect the command to take 30 minutes on even a fast connection, and many hours on slower ones.
If you've already installed the build dependencies on the machine (from another checkout, for example), you can omit the --nohooks
flag and fetch
will automatically execute gclient runhooks
at the end.
When fetch
completes, it will have created a hidden .gclient
file and a directory called src
in the working directory. The remaining instructions assume you have switched to the src
directory:
cd src
If you have an existing Linux checkout, you can add Android support by appending target_os = ['linux', 'android']
to your .gclient
file (in the directory above src
):
echo "target_os = [ 'linux', 'android' ]" >> ../.gclient
Then run gclient sync
to pull the new Android dependencies:
gclient sync
(This is the only difference between fetch android
and fetch chromium
.)
Once you have checked out the code, run
build/install-build-deps.sh
to get all of the dependencies you need to build on Linux, plus all of the Android-specific dependencies (you need some of the regular Linux dependencies because an Android build includes a bunch of the Linux tools and utilities).
NOTE: For 32-bit builds, the --lib32
command line switch could be used. You may run into issues where gperf
or pkgconf
don't get installed, without it. To remedy this, and potentially other missing packages, you will have to install them manually using:
sudo apt-get install {missing_pkg}
Once you've run install-build-deps
at least once, you can now run the Chromium-specific hooks, which will download additional binaries and other things you might need:
gclient runhooks
Optional: You can also install API keys if you want your build to talk to some Google services, but this is not necessary for most development and testing purposes.
Chromium uses Ninja as its main build tool along with a tool called GN to generate .ninja
files. You can create any number of build directories with different configurations. To create a build directory which builds Chrome for Android, run gn args out/Default
and edit the file to contain the following arguments:
target_os = "android" target_cpu = "arm64" # See "Figuring out target_cpu" below use_remoteexec = true # Enables distributed builds. See "Faster Builds".
Default
with another name, but it should be a subdirectory of out
.gn help
on the command line or read the quick start guide.Also be aware that some scripts (e.g. tombstones.py
, adb_gdb.py
) require you to set CHROMIUM_OUTPUT_DIR=out/Default
.
The value of target_cpu
determines what instruction set to use for native code. Given a device (or emulator), you can determine the correct instruction set with adb shell getprop ro.product.cpu.abi
:
getprop ro.product.cpu.abi output | target_cpu value |
---|---|
arm64-v8a | arm64 |
armeabi-v7a | arm |
x86 | x86 |
x86_64 | x64 |
arm
and x86
may optionally be used instead of arm64
and x64
for non-WebView targets. This is also allowed for Monochrome, but only when not set as the WebView provider.Build Chromium with Ninja using the command:
autoninja -C out/Default chrome_public_apk
(autoninja
is a wrapper that automatically provides optimal values for the arguments passed to ninja
.)
You can get a list of all of the other build targets from GN by running gn ls out/Default
from the command line. To compile one, pass the GN label to Ninja with no preceding “//” (so, for //chrome/test:unit_tests
use autoninja -C out/Default chrome/test:unit_tests
).
The Google Play Store allows apps to send customized bundles (.aab
files) depending on the version of Android running on a device. Chrome uses this feature to package optimized versions for different OS versions.
monochrome_public_bundle
(MonochromePublic.aab
)minSdkVersion=26
(Oreo).trichrome_chrome_bundle
(TrichromeChrome.aab
)minSdkVersion=29
(Android 10).trichrome_library_apk
trichrome_webview_bundle
chrome_public_bundle
& chrome_public_apk
(ChromePublic.aab
, ChromePublic.apk
)minSdkVersion=26
(Oreo).system_webview_bundle
/ system_webview_apk
).Notes:
chrome_public_apk
, but any of the other targets can be substituted.To update an existing checkout, you can run
$ git rebase-update $ gclient sync
The first command updates the primary Chromium source repository and rebases any of your local branches on top of tip-of-tree (aka the Git branch origin/main
). If you don't want to use this script, you can also just use git pull
or other common Git commands to update the repo.
The second command syncs dependencies to the appropriate versions and re-runs hooks as needed.
Make sure your Android device is plugged in via USB, and USB Debugging is enabled.
To enable USB Debugging:
You may also be prompted to allow access to your PC once your device is plugged in.
You can check if the device is connected by running:
third_party/android_sdk/public/platform-tools/adb devices
Which prints a list of connected devices. If not connected, try unplugging and reattaching your device.
Allow Android to run APKs that haven't been signed through the Play Store:
In case that setting isn't present, it may be possible to configure it via adb shell
instead:
third_party/android_sdk/public/platform-tools/adb shell settings put global verifier_verify_adb_installs 0
autoninja -C out/Default chrome_public_apk
And deploy it to your Android device:
out/Default/bin/chrome_public_apk install
The app will appear on the device as “Chromium”.
Wraps the content module (but not the /chrome embedder). See https://www.chromium.org/developers/content-module for details on the content module and content shell.
autoninja -C out/Default content_shell_apk out/Default/bin/content_shell_apk install
this will build and install an Android apk under out/Default/apks/ContentShell.apk
.
Android WebView is a system framework component. Since Android KitKat, it is implemented using Chromium code (based off the content module).
If you want to build the complete Android WebView framework component and test the effect of your chromium changes in Android apps using WebView, you should follow the Android AOSP + chromium WebView instructions
For Content shell:
out/Default/bin/content_shell_apk launch [--args='--foo --bar'] http://example.com
For Chrome public:
out/Default/bin/chrome_public_apk launch [--args='--foo --bar'] http://example.com
Logging is often the easiest way to understand code flow. In C++ you can print log statements using the LOG macro. In Java, refer to android_logging.md.
You can see these log via adb logcat
, or:
out/Default/bin/chrome_public_apk logcat
Logcat supports an additional feature of filtering and highlighting user-defined patterns. To use this mechanism, define a shell variable: CHROMIUM_LOGCAT_HIGHLIGHT
and assign your desired pattern. The pattern will be used to search for any substring (ie. no need to prefix or suffix it with .*
), eg:
export CHROMIUM_LOGCAT_HIGHLIGHT='(WARNING|cr_Child)' out/Default/bin/chrome_public_apk logcat # Highlights messages/tags containing WARNING and cr_Child strings.
Note: both Message and Tag portion of logcat are matched against the pattern.
To debug C++ code, use one of the following commands:
out/Default/bin/content_shell_apk gdb out/Default/bin/chrome_public_apk gdb
See Android Debugging Instructions for more on debugging, including how to debug Java code.
For information on running tests, see Android Test Instructions
Chromium's build can be sped up significantly by using a remote execution system compatible with REAPI. This allows you to benefit from remote caching and executing many build actions in parallel on a shared cluster of workers.
To use Reclient, follow the corresponding Linux build instructions.
Args that affect build speed:
use_remoteexec = true
(default=false)symbol_level = 0
(default=1)blink_symbol_level = 0
, v8_symbol_level = 0
is_component_build = true
(default=is_debug
).so
files instead of just one (faster links)is_java_debug = true
(default=is_debug
)treat_warnings_as_errors = false
(default=true
)android_static_analysis = "build_server"
(default="on"
)"off"
if you want to turn off static analysis altogether.incremental_install = true
(default=false
)enable_chrome_android_internal = false
(Googlers only)Normally analysis build steps like Lint and Error Prone will run as normal build steps. The build will then wait for all analysis steps to complete successfully. By offloading analysis build steps to a separate build server to be run lazily at a low priority when the machine is idle, the actual build can complete much faster.
Note: Since the build completes before the analysis checks finish, the build will not fail if an analysis check fails. Make sure to check the server's output at regular intervals to fix outstanding issues caught by these analysis checks.
There are two steps to using the build server.
android_static_analysis = "build_server"
All your local builds will now forward analysis steps to this server, including android lint, errorprone, bytecode processor.
If you run (2) in a terminal, the output of the checks will be displayed there.
Alternatively, you can set up the server as a Linux service, so it runs on the background and starts on boot. If you're using systemd:
Save the following as /etc/systemd/user/fast-local-dev-server.service.
[Unit] Description=Chrome server for android build static analysis [Service] Type=simple ExecStart=<path to fast_local_dev_server.py> Restart=always [Install] WantedBy=default.target
Then
systemctl --user daemon-reload systemctl --user enable fast-local-dev-server systemctl --user start fast-local-dev-server
The output can be inspected with
journalctl --user -e -u fast-local-dev-server
Incremental Install uses reflection and sideloading to speed up the edit & deploy cycle (normally < 10 seconds). The initial launch of the apk will be a lot slower on older Android versions (pre-N) where the OS needs to pre-optimize the side-loaded files, but then be only marginally slower after the first launch.
To enable Incremental Install, add the gn args:
incremental_install = true
Some APKs (e.g. WebView) do not work with incremental install = true
and are always built as normal APKs. This behavior is controlled via never_incremental = true
.
Running on an emulator is the same as on a device. Refer to android_emulator.md for setting up emulators.
These instructions are only necessary for Chrome 51 and earlier.
In the case where you want to modify the native code for an existing release of Chrome for Android (v25+) you can do the following steps. Note that in order to get your changes into the official release, you'll need to send your change for a codereview using the regular process for committing code to chromium.
To build Chromium for Android using Docker, please follow the instructions in the Docker in Linux build instructions.