We began parsing SVG documents as HTML years ago in commit 05be648. This
was long before we had an XML parser, and actually violates the spec.
Since SVG documents have a MIME type of "image/svg+xml", the spec
mandates the document should be parsed as XML.
One impact here is that the SVG document is no longer "fixed" to include
<html>, <head>, and <body> tags. This will have prevented document.title
from detecting the document element is an SVG element.
Implements:
https://html.spec.whatwg.org/multipage/browsing-the-web.html#attempt-to-populate-the-history-entry's-document
This is going to be a replacement for `FrameLoader::load()` after
switching to navigables.
Brief description of `populate_session_history_entry_document`:
- If navigation params have url with fetch scheme then DOM document
will be populated by fetching url and parsing response. This
is going to be a replacement for `FrameLoader::load(AK::URL&)`.
- If url in navigation params is abort:srcdoc then DOM document
will be populated by parsing HTML text passed in document resource.
This is going to be a replacement for `FrameLoader::load_html()`
