AK: Percent encode URL fragments when parsed

This fixes URL fragments containing characters in the fragment encoding
set that were not being correctly percent encoded.

AK/URLParser.cpp

@@ -1635,10 +1635,11 @@ URL URLParser::basic_parse(StringView raw_input, Optional<URL> const& base_url,
                 if (code_point == '%' && !remaining_starts_with_two_ascii_hex_digits())
                     report_validation_error();
 
-                // FIXME: 3. UTF-8 percent-encode c using the fragment percent-encode set and append the result to url’s fragment.
+                // 3. UTF-8 percent-encode c using the fragment percent-encode set and append the result to url’s fragment.
+                // NOTE: The percent-encode is done on EOF on the entire buffer.
                 buffer.append_code_point(code_point);
             } else {
-                url->m_fragment = buffer.to_string().release_value_but_fixme_should_propagate_errors();
+                url->m_fragment = String::from_deprecated_string(percent_encode_after_encoding(buffer.string_view(), URL::PercentEncodeSet::Fragment)).release_value_but_fixme_should_propagate_errors();
                 buffer.clear();
             }
             break;

Tests/LibWeb/Text/expected/URL/url.txt

@@ -48,3 +48,13 @@ port => '0'
 pathname => ''
 search => ''
 hash => ''
+http://serenityos.org/cat?dog#meow"woof
+protocol => 'http:'
+username => ''
+password => ''
+host => 'serenityos.org'
+hostname => 'serenityos.org'
+port => ''
+pathname => '/cat'
+search => '?dog'
+hash => '#meow%22woof'

Tests/LibWeb/Text/input/URL/url.html

@@ -21,6 +21,7 @@
             'http://[1:0:1:0:1:0:1:0]',
             'http://[1:1:0:0:1:0:0:0]/',
             'unknown://serenityos.org:0',
+            'http://serenityos.org/cat?dog#meow"woof',
         ]) {
             printURL(url);
         }