LibWeb: Support comments in the "in head" insertion mode

Libraries/LibWeb/Parser/HTMLDocumentParser.cpp

@@ -25,6 +25,7 @@
  */
 
 #include <AK/Utf32View.h>
+#include <LibWeb/DOM/Comment.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/DocumentType.h>
 #include <LibWeb/DOM/ElementFactory.h>
@@ -34,9 +35,9 @@
 #include <LibWeb/Parser/HTMLDocumentParser.h>
 #include <LibWeb/Parser/HTMLToken.h>
 
-#define TODO()                                                                                              \
-    do {                                                                                                    \
-        ASSERT_NOT_REACHED();                                                                               \
+#define TODO()                \
+    do {                      \
+        ASSERT_NOT_REACHED(); \
     } while (0)
 
 namespace Web {
@@ -179,6 +180,13 @@ void HTMLDocumentParser::handle_before_head(HTMLToken& token)
     ASSERT_NOT_REACHED();
 }
 
+void HTMLDocumentParser::insert_comment(HTMLToken& token)
+{
+    auto data = token.m_comment_or_character.data.to_string();
+    auto adjusted_insertion_location = find_appropriate_place_for_inserting_node();
+    adjusted_insertion_location->append_child(adopt(*new Comment(document(), data)));
+}
+
 void HTMLDocumentParser::handle_in_head(HTMLToken& token)
 {
     if (token.is_parser_whitespace()) {
@@ -186,6 +194,11 @@ void HTMLDocumentParser::handle_in_head(HTMLToken& token)
         return;
     }
 
+    if (token.is_comment()) {
+        insert_comment(token);
+        return;
+    }
+
     if (token.is_start_tag() && token.tag_name() == "title") {
         insert_html_element(token);
         m_tokenizer.switch_to({}, HTMLTokenizer::State::RCDATA);

Libraries/LibWeb/Parser/HTMLDocumentParser.h

@@ -96,6 +96,7 @@ private:
     RefPtr<Element> insert_html_element(HTMLToken&);
     Element& current_node();
     void insert_character(u32 data);
+    void insert_comment(HTMLToken&);
     void reconstruct_the_active_formatting_elements();
     void process_using_the_rules_for(InsertionMode, HTMLToken&);