I'm currently integrating the WebRTC interface into a browser-like project by directly calling into their C++ code (when Java is the preferred interface). Most of the process so far has been trial-and-error (especially with hooking up their JNI calls back to Android from C++ land in order to access Android audio device info and state that can't be reached from C++). The code base is quite large and so gaining familiarity with it has been challenging.
I can see how a single engineer's time is necessary for this project, as I've already sunk over a week of work into my own integration, and I've only gotten the peering to work so far (audio is just about there).
Supposedly many years ago, there used to be an example inside the code base of what I am currently trying to pull off, but nevermore.
It is quite challenging to just integrate WebRTC -- one does not simply integrate WebRTC.