Auto merge of #19647 - tigercosmos:x3, r=jdm

replace DocumentSource::NotFromParser with DocumentSource::FromParser

<!-- Please describe your changes on the following line: -->
per https://github.com/servo/servo/pull/4297/files#r158729975

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/19647)
<!-- Reviewable:end -->

components/script/dom/domparser.rs

@@ -77,7 +77,6 @@ impl DOMParserMethods for DOMParser {
                 Ok(document)
             }
             Text_xml | Application_xml | Application_xhtml_xml => {
-                // FIXME: this should probably be FromParser when we actually parse the string (#3756).
                 let document = Document::new(&self.window,
                                              HasBrowsingContext::No,
                                              Some(url.clone()),
@@ -86,12 +85,13 @@ impl DOMParserMethods for DOMParser {
                                              Some(content_type),
                                              None,
                                              DocumentActivity::Inactive,
-                                             DocumentSource::NotFromParser,
+                                             DocumentSource::FromParser,
                                              loader,
                                              None,
                                              None,
                                              Default::default());
                 ServoParser::parse_xml_document(&document, s, url);
+                document.set_ready_state(DocumentReadyState::Complete);
                 Ok(document)
             }
         }