README for TBLWebView
This explains how to build a custom native library for TBLWebView.
To be able to run the final WebViewInstrumentation APK, you need to obtain a dynamically linked build apk (shared library version) provided along with this source code package. From provided sources you may build dynamic libraries for the open source parts, and replace the ones from TBLWebView with them.
cd chromium/src
gn args out/Release
When the editor shows up, you need to add "is_component_build=true".
Then you can build your custom library.
ninja -C out/Release <custom_lib>
The custom library can be exchanged with the one used in dynamically linked build.