Please do not do this. Webgl and Webrtc are fundamental technologies needed to efficiently do basic activities like process an image or send sound data to another user.
I am all for a "lighter" browser, by removing UI, removing dev tools, etc. Get rid of the stuff that's not required to make a web page work well. But WebGL and WebRTC are cornerstone technologies for the web to thrive. WebRTC is critical for allowing open source software to thrive in particular (allows apps that don't need a central server) and WebGL is critical in particular for web software to compete in the AR/VR age. We need 100% browser support on these two APIs, and we need it yesterday.
I realize these technologies are not currently doing anything for you. I sympathize. But we need them in browsers now so that we can use them in 10 years.
Please, please, please jetsam other parts of the ship before you cut those features.