You'd be eating noodles, rice and slop. Take the current scenario here and amplify it 20 times or more, you get the picture. 

Did you read "The Man in The High Castle" by Philip K. Dick ? It describes what would be the 60's (or was it the 70's), given that Nazi Germany and Imperial Japan won WWII, USA is split into between both. Some form of cold war is going on.

I would be speaking Chinese as 2nd language, working in the Federation of Central Africa, where's the real deal is happening, while the old empire of China is starting to crumble, slowly. I would grumble about those Europeans who can't reform themselves, who can't look at themselves honestly for 1 minute, feeling every damn city with an Euro-town full of sweatshop and illegal migrants, etc.

Do you think in this alternate Universe-

1)Anybody who doesn't look Chinese will be treated as second   grade citizen

(your look and blood will decide whether you a "Chinese Citizen" or  "a poor subject"

2)non-Chinese ideas,habits,thoughts will be gradually eliminated from the face of earth

3)Chinese will gradually outbreed others and by end of 21st century,world is 90% Chinese and rest of us reduced to minority

4)All will be 'forced' to adopt Chinese believes and life-style

5)Non-Chinese will never be treated equal in a Chinese World

6)The entire world gradually become "a Bigger China"...

7)Essentially,all non-Chinese looking people will either disappear and will be reduced

to "sample minority population"..culturally,linguistically,demographically...

 or it will be the opposite..any thought!

Do you have an agenda with this?

Is it a commentary on the perceived pervasiveness of "Western" culture and standards?

Are you a Chinese apologist?

In this situation, do we also presume that most migration has happened towards China? And that China gladly opened its doors to those immigrants and let them assimilate?

Did China colonise the Americas?

Did they take Confusicanism and Taosim to the new lands?

If we really want to consider this, and it is a valid argument*, then we have to ask these questions! I suspect that China would be vastly different! Certainly no CCP (or, perhaps, it took over a century or more ago..).

*it's valid, cos they had gunpowder! If they had bothered to learn it's most powerful use, then it's quite possible this scenario could have come to being!

Am I supposed to feel sorry for chinese people? Your scenario neglects one basic fact. This did happen to many of us... really, I am black. And you know what. .. I don't give a rats ass. The past is the past , accept it and live your life.
There are many variables missing from your scenario.
Is my country a pathetic 3 inch mentality country? Does my country teaches a made up version of history? Does my country teaches it's people to hate everyone who is not my ethnicity? Does my country try to bully it's peaceful neighbors? Does

When everyone outside of China looks back on the history of the world, they say all the war , colonization and slavery are bad and should not have happened. Those who did the wrongs apologize and they work together to make sure it doesn't happen again. 

But when Chinese people look back on the history of the world they say, "it should have been us enslaving the world, everyone should feel sorry for China because China did not dominate the world." 

And you wonder why China has no friends. 

Can you imagine everyone being made to shat and piss on the floor, in buses, planes and trains. Oh wait those inventions would never exist.

What about England's great leap forward and cultural revolution?  

In this alternate reality females would be aborted because chinese men prefer boys. And incest and rape would not be punishable.

That is an interesting question. Let me think about it.

Erm.

Lets not forget the UK want Chinese Maths teachers:

http://www.bbc.com/news/education-26541586

I don't think advert should specify 'Chinese Native speaker'! There're too many of them.