• https://webrtc.googlesource.com/src/+/master/webrtc/sdk/android/api/org/webrtc
• https://webrtc.googlesource.com/src/+/master/webrtc/sdk/android/src/java/org/webrtc
• https://webrtc.googlesource.com/src/+/master/webrtc/rtc_base/java/src/org/webrtc
• https://webrtc.googlesource.com/src/+/master/webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine
• https://webrtc.googlesource.com/src/+/master/webrtc/examples/androidapp/

Edit gradle.properties, set compile_native_code=true and other variables according to your WebRTC checkout location, then enjoy :)

Note:

• use the same version of Android SDK and NDK;
• recreate protoc after updating webrtc repo, build WebRTC with ninja would create it;
• delete webrtc_build_dir after updating webrtc repo;