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# Checking out and building Chromium for Android
There are instructions for other platforms linked from the
[get the code]( page.
## Instructions for Google Employees
Are you a Google employee? See
[go/building-chrome]( instead.
## System requirements
* A 64-bit Intel machine running Linux with at least 8GB of RAM. More
than 16GB is highly recommended.
* At least 100GB of free disk space.
* You must have Git and Python installed already.
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.
## Install `depot_tools`
Clone the `depot_tools` repository:
git clone
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"
## Get the code
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
### Converting an existing Linux checkout
If you have an existing Linux checkout, you can add Android support by
appending `target_os = ['android']` to your `.gclient` file (in the
directory above `src`):
echo "target_os = [ '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`.)
### Install additional build dependencies
Once you have checked out the code, run
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).
### Run the hooks
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.
## Setting up the build
Chromium uses [Ninja]( as its main build tool along
with a tool called [GN](../tools/gn/docs/ 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,
gn gen --args='target_os="android"' out/Default
* You only have to run this once for each new build directory, Ninja will
update the build files as needed.
* You can replace `Default` with another name, but
it should be a subdirectory of `out`.
* For other build arguments, including release settings, see [GN build
The default will be a debug component build matching the current host
operating system and CPU.
* For more info on GN, run `gn help` on the command line or read the
[quick start guide](../tools/gn/docs/
Also be aware that some scripts (e.g. ``, ``)
require you to set `CHROMIUM_OUTPUT_DIR=out/Default`.
## Build Chromium
Build Chromium with Ninja using the command:
ninja -C out/Default chrome_public_apk
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 `ninja -C
out/Default chrome/test:unit_tests`).
### Multiple Chrome APK Targets
The Google Play Store allows apps to send customized `.apk` files depending on
the version of Android running on a device. Chrome uses this feature to target
3 different versions using 3 different ninja targets:
1. `chrome_public_apk` (ChromePublic.apk)
* `minSdkVersion=16` (Jelly Bean).
* Stores compressed within the APK.
* Uses [Crazy Linker](
* Shipped only for Android < 21, but still works fine on Android >= 21.
2. `chrome_modern_public_apk` (ChromeModernPublic.apk)
* `minSdkVersion=21` (Lollipop).
* Uses [Crazy Linker](
* Stores uncompressed within the APK.
* This APK is bigger, but the installation size is smaller since there is
no need to extract the .so file.
3. `monochrome_public_apk` (MonochromePublic.apk)
* `minSdkVersion=24` (Nougat).
* Contains both WebView and Chrome within the same APK.
* This APK is even bigger, but much smaller than SystemWebView.apk + ChromePublic.apk.
* Stores uncompressed within the APK.
* Does not use Crazy Linker (WebView requires system linker).
* But system linker supports crazy linker features now anyways.
**Note**: These instructions use `chrome_public_apk`, but either of the other
two targets can be substituted.
**Note**: These targets are actually the open-source equivalents to the
closed-source targets that get shipped to the Play Store.
## Updating your checkout
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/master`). 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.
## Installing and Running Chromium on a device
### Plug in your Android device
Make sure your Android device is plugged in via USB, and USB Debugging
is enabled.
To enable USB Debugging:
* Navigate to Settings \> About Phone \> Build number
* Click 'Build number' 7 times
* Now navigate back to Settings \> Developer Options
* Enable 'USB Debugging' and follow the prompts
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_tools/sdk/platform-tools/adb devices
Which prints a list of connected devices. If not connected, try
unplugging and reattaching your device.
### Build the full browser
ninja -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".
### Build Content shell
Wraps the content module (but not the /chrome embedder). See
for details on the content module and content shell.
ninja -C out/Default content_shell_apk
out/Default/bin/content_shell_apk install
this will build and install an Android apk under
### Build WebView
[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
### Running
For Content shell:
out/Default/bin/content_shell_apk launch [--args='--foo --bar']
For Chrome public:
out/Default/bin/chrome_public_apk launch [--args='--foo --bar']
### Logging and debugging
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
You can see these log via `adb logcat`, or:
out/Default/bin/chrome_public_apk logcat
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.
### Testing
For information on running tests, see [Android Test Instructions](
### Faster Edit/Deploy
"Incremental install" uses reflection and side-loading to speed up the edit
& deploy cycle (normally < 10 seconds). The initial launch of the apk will be
a little slower since updated dex files are installed manually.
* Make sure to set` is_component_build = true `in your GN args
* All apk targets have \*`_incremental` targets defined (e.g.
`chrome_public_apk_incremental`) except for Webview and Monochrome
Here's an example:
ninja -C out/Default chrome_public_apk_incremental
out/Default/bin/chrome_public_apk install --incremental --verbose
For gunit tests (note that run_*_incremental automatically add
`--fast-local-dev` when calling ``):
ninja -C out/Default base_unittests_incremental
For instrumentation tests:
ninja -C out/Default chrome_public_test_apk_incremental
To uninstall:
out/Default/bin/chrome_public_apk uninstall
To avoid typing `_incremental` when building targets, you can use the GN arg:
incremental_apk_by_default = true
This will make `chrome_public_apk` build in incremental mode.
## Tips, tricks, and troubleshooting
### Rebuilding for a particular release
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.
1. Open Chrome on your Android device and visit chrome://version
2. Copy down the id listed next to "Build ID:"
3. Go to
4. Download the listed files and follow the steps in the README.