LibWeb: Implement CSS::Token::to_string()

This outputs valid CSS, as opposed to to_debug_string().

Userland/Libraries/LibWeb/CSS/Parser/Token.cpp

@@ -6,9 +6,71 @@
 
 #include <AK/String.h>
 #include <LibWeb/CSS/Parser/Token.h>
+#include <LibWeb/CSS/Serialize.h>
 
 namespace Web::CSS {
 
+String Token::to_string() const
+{
+    StringBuilder builder;
+
+    switch (m_type) {
+    case Type::EndOfFile:
+        return "";
+    case Type::Ident:
+        return serialize_an_identifier(ident());
+    case Type::Function:
+        return String::formatted("{}(", serialize_an_identifier(function()));
+    case Type::AtKeyword:
+        return String::formatted("@{}", serialize_an_identifier(at_keyword()));
+    case Type::Hash:
+        return String::formatted("#{}", serialize_an_identifier(hash_value()));
+    case Type::String:
+        return serialize_a_string(string());
+    case Type::BadString:
+        return "";
+    case Type::Url:
+        return serialize_a_url(url());
+    case Type::BadUrl:
+        return "url()";
+    case Type::Delim:
+        return m_value;
+    case Type::Number:
+        return String::number(m_number_value);
+    case Type::Percentage:
+        return String::formatted("{}%", m_number_value);
+    case Type::Dimension:
+        return String::formatted("{}{}", m_number_value, m_unit);
+    case Type::Whitespace:
+        return " ";
+    case Type::CDO:
+        return "<!--";
+    case Type::CDC:
+        return "-->";
+    case Type::Colon:
+        return ":";
+    case Type::Semicolon:
+        return ";";
+    case Type::Comma:
+        return ",";
+    case Type::OpenSquare:
+        return "[";
+    case Type::CloseSquare:
+        return "]";
+    case Type::OpenParen:
+        return "(";
+    case Type::CloseParen:
+        return ")";
+    case Type::OpenCurly:
+        return "{";
+    case Type::CloseCurly:
+        return "}";
+    case Type::Invalid:
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
 String Token::to_debug_string() const
 {
     StringBuilder builder;

Userland/Libraries/LibWeb/CSS/Parser/Token.h

@@ -157,6 +157,7 @@ public:
     String bracket_string() const;
     String bracket_mirror_string() const;
 
+    String to_string() const;
     String to_debug_string() const;
 
     Position const& start_position() const { return m_start_position; }