LibWeb: Use correct URL parsing methods throughout LibWeb

There are essentially 3 URL parsing AOs defined by the spec:
1. Parse a URL
2. Encoding parse a URL
3. Encoding parse a URL and serialize the result

Further, these are replicated between the Document and the ESO.

This patch defines these methods in accordance with the spec and updates
existing users to invoke the correct method. In places where the correct
method is ambiguous, we use the encoding parser to preserve existing ad-
hoc behavior.

Libraries/LibWeb/HTML/Scripting/Environments.cpp

@@ -11,6 +11,7 @@
 #include <LibWeb/Bindings/PrincipalHostDefined.h>
 #include <LibWeb/Bindings/SyntheticHostDefined.h>
 #include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOMURL/DOMURL.h>
 #include <LibWeb/Fetch/Infrastructure/FetchRecord.h>
 #include <LibWeb/HTML/Scripting/Environments.h>
 #include <LibWeb/HTML/Scripting/ExceptionReporter.h>
@@ -201,17 +202,45 @@ void prepare_to_run_callback(JS::Realm& realm)
 // https://html.spec.whatwg.org/multipage/urls-and-fetching.html#parse-a-url
 URL::URL EnvironmentSettingsObject::parse_url(StringView url)
 {
-    // 1. Let encoding be document's character encoding, if document was given, and environment settings object's API URL character encoding otherwise.
-    // FIXME: Pass in environment settings object's API URL character encoding.
-
-    // 2. Let baseURL be document's base URL, if document was given, and environment settings object's API base URL otherwise.
+    // 1. Let baseURL be environment's base URL, if environment is a Document object; otherwise environment's API base URL.
     auto base_url = api_base_url();
 
-    // 3. Let urlRecord be the result of applying the URL parser to url, with baseURL and encoding.
-    // 4. If urlRecord is failure, then return failure.
-    // 5. Let urlString be the result of applying the URL serializer to urlRecord.
-    // 6. Return urlString as the resulting URL string and urlRecord as the resulting URL record.
-    return base_url.complete_url(url);
+    // 2. Return the result of applying the URL parser to url, with baseURL.
+    return DOMURL::parse(url, base_url);
+}
+
+// https://html.spec.whatwg.org/multipage/urls-and-fetching.html#encoding-parsing-a-url
+URL::URL EnvironmentSettingsObject::encoding_parse_url(StringView url)
+{
+    // 1. Let encoding be UTF-8.
+    auto encoding = "UTF-8"_string;
+
+    // 2. If environment is a Document object, then set encoding to environment's character encoding.
+
+    // 3. Otherwise, if environment's relevant global object is a Window object, set encoding to environment's relevant
+    //    global object's associated Document's character encoding.
+    if (is<HTML::Window>(global_object()))
+        encoding = static_cast<HTML::Window const&>(global_object()).associated_document().encoding_or_default();
+
+    // 4. Let baseURL be environment's base URL, if environment is a Document object; otherwise environment's API base URL.
+    auto base_url = api_base_url();
+
+    // 5. Return the result of applying the URL parser to url, with baseURL and encoding.
+    return DOMURL::parse(url, base_url, encoding);
+}
+
+// https://html.spec.whatwg.org/multipage/urls-and-fetching.html#encoding-parsing-and-serializing-a-url
+Optional<String> EnvironmentSettingsObject::encoding_parse_and_serialize_url(StringView url)
+{
+    // 1. Let url be the result of encoding-parsing a URL given url, relative to environment.
+    auto parsed_url = encoding_parse_url(url);
+
+    // 2. If url is failure, then return failure.
+    if (!parsed_url.is_valid())
+        return {};
+
+    // 3. Return the result of applying the URL serializer to url.
+    return parsed_url.serialize();
 }
 
 // https://html.spec.whatwg.org/multipage/webappapis.html#clean-up-after-running-a-callback