I don't understand your point. Yes, it's using WebGL. Do you think that it's going to do WebGL -> OpenGL ES 2/3 calls -> ANGLE -> Direct3D -> PS4 graphics driver (like it does on e.g. chrome on windows) ? No, it's likely doing WebGL -> PS4 proprietary graphics API -> PS4 graphics driver, not going through ANGLE or whatnot
but why would it go through ANGLE's libGLESv2.so and add a backend to that for the PS4 when the PS4 team could most likely provide their own libGLESv2 which maps directly to their driver (since they were doing that already for the PS3) ? As this is what chrome actually calls, gles functions.
Unless I missed something, when were they doing that with PS3?
The only effort to do any GL like stuff was on the PS2, with GL ES 1.0 + Cg, an effort that was dropped when almost no dev cared to use it.
Other than that there was the PSGL library for PS2 Linux.
Anyway, I did a bit more research and Chrome was actually only used for development purposes, they created their own WebGL engine on top of PhyreEngine for the console OS.
https://news.softpedia.com/news/The-PS4-UI-Is-Built-Using-We...