How would I save my preferences?
Do all websites have to be compiled as programs first, so they can be input as programs into new Chrome?
If my websites were provided as input and compiled into Chrome, how do I avoid rebuilding Chrome when the websites are updated?
If Chrome is the compiler, then Chrome is allowed to do all the I/O it wants, just like it does right now?
You save your preferences the same way you might save `jquery.js` on your computer.
Chrome IS the compiler, you don't need to compile them first to give them to Chrome.
I'm not sure what you mean by "compiled into Chrome". Since when you do compile a program "into" the compiler? Look, your browser probably JIT compiled a dozen programs just for you to be able to view this page and comment. Did you need to rebuild Chrome?
Yes, Chrome is doing the IO. Importantly, the page is NOT doing the IO. So, there's no XMLHttpRequest, for example.
Chrome is allowed to do whatever I/O it wants, but the programs it interprets (like user settings and web pages) are not allowed to do any I/O at all. These interpreted programs are sandboxed.
This isn't really surprising if you think about it. Chrome is already an interpreter for a sandboxed language (JavaScript)