Rewrote DOM integration

[koto]

This adds an entry point algorithm to call from DOM's append, change, and replace algorithms for Attr nodes.

whatwg/dom#789
Closes #401.

[annevk]

I haven't restudied the wider context, but I have some comments even without context. Hope they are helpful.

[annevk]

This green bit looks pretty solid to me now (modulo test coverage).

[mbrodesser-Igalia]

Couldn't add an inline comment for https://github.com/w3c/trusted-types/pull/418/files#diff-40cc3a1ba233cc3ca7b6d5873260da9676f6ae20bb897b62f7871c80d0bda4e9R1060-L1059, hence here: don't those lines imply

someIframe.setAttribute("srcdoc", "someHtml");

would set the srcdoc's value to "someHtml", because someIframe's global differs from the embedding document's global?

Asking because of #425 (comment).

CC @koto

[koto]

don't those lines imply

someIframe.setAttribute("srcdoc", "someHtml");

would set the srcdoc's value to "someHtml", because someIframe's global differs from the embedding document's global?

Isn't iframe element global the same? Only its content window can have a different global.

[mbrodesser-Igalia]

don't those lines imply

someIframe.setAttribute("srcdoc", "someHtml");

would set the srcdoc's value to "someHtml", because someIframe's global differs from the embedding document's global?

Isn't iframe element global the same?

It should be. Thanks for the context.

Only its content window can have a different global.