This is a problem I recently encountered when I was trying to upload a model to Sketchfab. It shown that WebGL in not supported. I opened
chrome://flags and enabled
override rendering list. However, even doing that didn't resolve much. I was able to see primitive preview of model in sketchfab(but not original) and 3D settings still weren't aviable. So here are some screenshots.
Version 43.0.2357.81 Ubuntu 15.04 (64-bit)
Full resolution: http://i.stack.imgur.com/RWvA1.png
Full resolution: http://i.stack.imgur.com/Z0P8E.png
Full resolution: http://i.stack.imgur.com/AYkDJ.png
I hope that someone can find a solution for this!