cc @aarongustafson

Create a document using JS + add an iframe, try to install

1. Let context be node document 's browsing context Firefox None
2. If context is null, then return false.
3. If context is not a top-level browsing context , return false.
   Testing plan for Adding link[rel=manifest] whatwg/html#5581

Fetching test

1. Set request 's initiator to " manifest ".
2. Set request 's destination to " manifest ".
3. Set request 's mode to " cors ".

Cross origin attribute

1. Empty, invalid, Anonymous
2. Use credentials - set a cookie, and see if it's sent.

Test the mine type

Test default fetch steps

1. If el 's href attribute's value is the empty string, then return.

Request tests:

1. Let request be the result of creating a potential-CORS request given url , the empty string, and corsAttributeState .
2. Set request 's synchronous flag .
3. Set request 's client to el 's node document 's relevant settings object .

Integrity check:

4. Set request 's cryptographic nonce metadata to the current value of el 's [[CryptographicNonce]] internal slot.
5. Set request 's integrity metadata to the current value of el 's integrity content attribute.

Referrer policy check:
6. Set request 's referrer policy to the current state of the el 's referrerpolicy attribute.

Critical sub resources:

1. icons downloaded and inherit CORS.