Oh I am not sure why I am wasting time answering as it seems like there is brick wall that is reading it.
As I said before Gwadar provides a alternate and a shorter route for the Chinese. It is mutually beneficial for us (financially) and for them(alternate shorter route, diplomatic clout etc). We are not responsible for protecting their trade routes they are responsible for securing their own trade routes. And furthermore any blockade of Chinese freedom of movement will mean war which I don't think US affords (also vice versa) so this topic of whether we will be protecting Chinese sea lanes is useless.
I was responding to the comment
" Touching Gawadar will be treated as full scale war and Pakistan have means to make life in Middle East very difficult for Americans "