Currently we create URLs such as 'about:blank' through the StringView
or ByteString constructor of URL. However, in order to elimate the
use of URL::is_valid, we need to get rid of these constructors as it
makes it way too easy to create an invalid URL.
It is very cumbersome to construct an 'about:blank' URL when using
URL::Parser::basic_parse. So instead of doing that, create some
helper functions which will create the 'about:XXX' URLs with the
correct properties set.
Conveniently, this is also a much faster way of creating these URLs
as it means we do not need to parse the URL and can set all of the
members up front.
Instead of just putting in members directly, wrap them up in structs
which represent what a URL blob entry is meant to hold per the spec.
This makes more obvious what this is meant to represent, such as the
ByteBuffer being used to represent the bytes behind a Blob.
This also allows us to use a stronger type for a function that needs
to return a Blob URL entry's object.
A couple of reasons:
- Origin's Host (when in the tuple state) can't be null
- There's an "empty host" concept in the spec which is NOT the same as a
null Host, and that was confusing me.
