WebGL Support

[Debadri-Redapple]

I'm trying to build and run the crowd demo scene in WebGL. However in the build none of the crowd is generated; only the plane is seen. Following error can be seen in the console:
Exception: Error, must invoke function from main thread! at GPUInstance.instancemesh.AssertInitializedAndMainThread () [0x00000] in <00000000000000000000000000000000>:0

Please look into this.
Attaching screenshot also for reference