Chrome on mobile has had support for WebGL for a while now, and from what you describe it is enabled on your device, due to scan lines working. You could check that both the operating system and the browser is up to date, although probably not the problem as support has been there for years now. The full capability may be hidden behind a flag in chrome, try navigating to chrome://flags and enabling 'Override software rendering list'. If this fails, could you list the devices you have tested on along with the version of android and chrome?