Cannot turn off WebPlayer Streaming?

When I build my project for web player it consumes twice more memory than a Windows version of same project. After profiling it I've found that half of memory in web build is taken by WebStream operation.

I suggest that WebStream operation stands for Streaming feature. However I have Streaming feature turned off (it was not checked in building settings while building). And WebStream operation still exists and still consumes that much memory.

I've created an empty project for test, and WebStream operation is still there, though consuming less memory. But once I start adding assets to the scene in that project the size of memory taken by WebStream becomes equal to total size of all assets in the scene.

So the question is whether I'm right in my suggestions that WebStream stands for Streaming? And is it a bug in Unity that it remains even if Streaming checkbox is unchecked on build?

Thank you.