Auto merge of #25627 - pshaughn:definedpseudo, r=emilio,jdm

Implement :defined CSS selector

<!-- Please describe your changes on the following line: -->
ElementState::IN_DEFINED_STATE already existed but wasn't hooked up to anything; now it is set appropriately, and CSS is aware of it. The main test for this selector needed the window named getter for no important reason, so I made a one-line test change to avoid that. Remaining failures in the test are all about SVG elements.

---
<!-- 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
- [X] These changes fix #25010

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

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tests/wpt/metadata/MANIFEST.json

@@ -667507,7 +667507,7 @@
    "testharness"
   ],
   "custom-elements/pseudo-class-defined.html": [
-   "24cb5fe4cd392246e292d255c0858aa7f2b5dd0e",
+   "ed12830d5a9582dbf3ec30c74a43fe381221a139",
    "testharness"
   ],
   "custom-elements/range-and-constructors.html": [

tests/wpt/metadata/custom-elements/Document-createElement.html.ini

@@ -1,3 +0,0 @@
-[Document-createElement.html]
-  [document.createElement must create an instance of autonomous custom elements when it has is attribute]
-    expected: FAIL

tests/wpt/metadata/custom-elements/pseudo-class-defined.html.ini

@@ -1,8 +1,37 @@
 [pseudo-class-defined.html]
-  expected: ERROR
   [Untitled]
     expected: FAIL
 
   [pseudo-class-defined]
     expected: FAIL
 
+  [createElementNS("http://www.w3.org/2000/svg", "div") should be :defined]
+    expected: FAIL
+
+  [Without browsing context: createElementNS("http://www.w3.org/2000/svg", "div") should be :defined]
+    expected: FAIL
+
+  [Without browsing context: createElementNS("http://www.w3.org/2000/svg", "p", { is: "" }) should be :defined]
+    expected: FAIL
+
+  [createElementNS("http://www.w3.org/2000/svg", "p", { is: "" }) should be :defined]
+    expected: FAIL
+
+  [Without browsing context: createElementNS("http://www.w3.org/2000/svg", "abbr", { is: "my-abbr" }) should be :defined]
+    expected: FAIL
+
+  [createElementNS("http://www.w3.org/2000/svg", "abbr", { is: "my-abbr" }) should be :defined]
+    expected: FAIL
+
+  [createElementNS("http://www.w3.org/2000/svg", "font-face") should be :defined]
+    expected: FAIL
+
+  [Without browsing context: createElementNS("http://www.w3.org/2000/svg", "font-face") should be :defined]
+    expected: FAIL
+
+  [createElementNS("http://www.w3.org/2000/svg", "a-a") should be :defined]
+    expected: FAIL
+
+  [Without browsing context: createElementNS("http://www.w3.org/2000/svg", "a-a") should be :defined]
+    expected: FAIL
+

tests/wpt/web-platform-tests/custom-elements/pseudo-class-defined.html

@@ -16,6 +16,7 @@ const testList = [
 const neither = 'rgb(255, 0, 0)';
 const defined = 'rgb(255, 165, 0)';
 const not_defined = 'rgb(0, 0, 255)';
+const iframe = document.getElementById("iframe");
 iframe.srcdoc = `<style>
   * { color:${neither}; }
   :defined { color:${defined}; }