Code review comment for lp:~thomir-deactivatedaccount/nux/lockrect-overloaded-method-hiding

Is this a warning that we get in Unity right now? I couldn't see it. How can I reproduce?

* I think we need to had a comment to say that "the value of slice must be zero" that for IOpenGLBaseTexture::LockRect.
* IOpenGLTexture2D::LockRect and IOpenGLRectangleTexture::LockRect have to be changed accordingly