Auto merge of #18747 - jdm:serializing-childrenonly, r=jdm

Serializing childrenonly

Rebased from #17896.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #14975 (github issue number if applicable).
- [x] There are tests for these changes

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components/script/dom/element.rs

@@ -2050,7 +2050,10 @@ impl ElementMethods for Element {
     /// https://w3c.github.io/DOM-Parsing/#widl-Element-innerHTML
     fn GetInnerHTML(&self) -> Fallible<DOMString> {
         // XXX TODO: XML case
-        self.serialize(ChildrenOnly)
+        let qname = QualName::new(self.prefix().clone(),
+                                  self.namespace().clone(),
+                                  self.local_name().clone());
+        self.serialize(ChildrenOnly(Some(qname)))
     }
 
     /// https://w3c.github.io/DOM-Parsing/#widl-Element-innerHTML

components/script/dom/servoparser/html.rs

@@ -21,7 +21,7 @@ use html5ever::QualName;
 use html5ever::buffer_queue::BufferQueue;
 use html5ever::serialize::{AttrRef, Serialize, Serializer};
 use html5ever::serialize::TraversalScope;
-use html5ever::serialize::TraversalScope::ChildrenOnly;
+use html5ever::serialize::TraversalScope::IncludeNode;
 use html5ever::tokenizer::{Tokenizer as HtmlTokenizer, TokenizerOpts, TokenizerResult};
 use html5ever::tree_builder::{Tracer as HtmlTracer, TreeBuilder, TreeBuilderOpts};
 use js::jsapi::JSTracer;
@@ -202,7 +202,7 @@ impl<'a> Serialize for &'a Node {
         let node = *self;
 
 
-        let iter = SerializationIterator::new(node, traversal_scope == ChildrenOnly);
+        let iter = SerializationIterator::new(node, traversal_scope != IncludeNode);
 
         for cmd in iter {
             match cmd {