Android Dev Tips

Just an internal tips page for people working on the memory team.

Building clank

See instructions on the official android build page for the most up to date info. However, it will tell you how to build everything which is way way more than you need and way way harder. In short, you mostly need to do 3 (well, 2) things:

  1. Create a gn out directory with target_os="android" in the GN args
  2. Disable NaCl. (not strictly necessary, but it makes Albert feel better)
  3. Build the chrome_public_apk

Too much text! I just want to run my thing!

Fine fine. First, ensure only one phone is attached. If you have multiple, you‘ll need to pass the device ID everywhere. Also, despite common wisdom, you do NOT have to root your phone.’s command lines to copy-🍝.

Get your environment setup (adb in your path, etc):

$ source build/android/

Incremental build/deploy:

$ ninja -C out/clank -j1000 chrome_public_apk && ./build/android/ --keep_data out/clank/apks/ChromePublic.apk && ( ./build/android/adb_kill_chrome_public ; ./build/android/adb_run_chrome_public )

Setting flags (see next part!):

$ ./build/android/adb_chrome_public_command_line --my-happy-flag-here

Select chromium as the system debug app to pick up flags!:

  • Go to the Developer Options in Android Settings
  • Find the Select debug app option.
  • Select Chromium (after your first install)

If you neglect to do this AND you do not have a rooted phone, the adb_chrome_public_command_line tool cannot write a command line file into the right location for your Chrome binary to read. When in doubt, verify the flags in about://version.

What is chrome_public_apk?

This seems to be the Android moral equivalent of the the chrome target on desktop. It builds the APK that you want to install on your phone to run your version of chromium.

Running logcat without going crazy.

Logcat dumps a lot of system messages on periodic timers which can be noisy. Often you just want to look at stack traces and things from chrome logs. This can be filtered with a command like the following:

adb logcat -s chromium:* ActivityManager:* WindowManager:* libc:* DEBUG:* System.err:*

The -s silences everything that's not explicitly listed by default. ActivityManager shows the android life-cycle events for Chrome. WindowManager shows window changes. libc and DEBUG show stack traces. System.err is the Java interpretation of the C failures. And chromium is obviously the bulk of the interesting messages.

Running telemetry (aka ./tools/perf/run_benchmark)

Passing in --device= with the correct id from adb devices will make the script talk to your phone. You will need to go to the Developer Options and force the screen to not lock. Then you can select the executable to run with one of:

--browser=exact --browser-executable=out/clank/apks/ChromePublic.apk

or if you want to run something already installed on the phone, there's a set of nifty options to --browser like: