Refactor ScriptLoader::IsValidScriptTypeAndLanguage()

Previously, it returns

- `mojom::blink::ScriptType`,
- `bool is_import_map` and
- a `bool` as a return value indicating whether the type is valid or not.

To unify these, this CL introduces `ScriptTypeAtPrepare`
that includes `kImportMap` and uses it throughout ScriptLoader.

Change-Id: I6573bb2c07b81c4161d7ad51c425ac6499e2bc3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593737
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#838780}

third_party/blink/renderer/core/html/html_script_element.cc

@@ -107,9 +107,10 @@ void HTMLScriptElement::ParseAttribute(
 Node::InsertionNotificationRequest HTMLScriptElement::InsertedInto(
     ContainerNode& insertion_point) {
   if (insertion_point.isConnected() && HasSourceAttribute() &&
-      !ScriptLoader::IsValidScriptTypeAndLanguage(
+      ScriptLoader::GetScriptTypeAtPrepare(
           TypeAttributeValue(), LanguageAttributeValue(),
-          ScriptLoader::kDisallowLegacyTypeInTypeAttribute)) {
+          ScriptLoader::kDisallowLegacyTypeInTypeAttribute) ==
+          ScriptLoader::ScriptTypeAtPrepare::kInvalid) {
     UseCounter::Count(GetDocument(),
                       WebFeature::kScriptElementWithInvalidTypeHasSrc);
   }

third_party/blink/renderer/core/html/parser/html_preload_scanner.cc

@@ -669,21 +669,24 @@ class TokenPreloadScanner::StartTagScanner {
     if (Match(tag_impl_, html_names::kInputTag) && !input_is_image_)
       return false;
     if (Match(tag_impl_, html_names::kScriptTag)) {
-      mojom::blink::ScriptType script_type = mojom::blink::ScriptType::kClassic;
-      bool is_import_map = false;
-      if (!ScriptLoader::IsValidScriptTypeAndLanguage(
+      ScriptLoader::ScriptTypeAtPrepare script_type =
+          ScriptLoader::GetScriptTypeAtPrepare(
               type_attribute_value_, language_attribute_value_,
-              ScriptLoader::kAllowLegacyTypeInTypeAttribute, &script_type,
-              &is_import_map)) {
-        return false;
-      }
-      if (is_import_map) {
-        // External import maps are not yet supported. https://crbug.com/922212
-        return false;
-      }
-      if (ScriptLoader::BlockForNoModule(script_type,
-                                         nomodule_attribute_value_)) {
-        return false;
+              ScriptLoader::kAllowLegacyTypeInTypeAttribute);
+      switch (script_type) {
+        case ScriptLoader::ScriptTypeAtPrepare::kInvalid:
+          return false;
+
+        case ScriptLoader::ScriptTypeAtPrepare::kImportMap:
+          // TODO(crbug.com/922212): External import maps are not yet supported.
+          return false;
+
+        case ScriptLoader::ScriptTypeAtPrepare::kClassic:
+        case ScriptLoader::ScriptTypeAtPrepare::kModule:
+          if (ScriptLoader::BlockForNoModule(script_type,
+                                             nomodule_attribute_value_)) {
+            return false;
+          }
       }
     }
     return true;

third_party/blink/renderer/core/html/parser/html_tree_builder_simulator.cc

@@ -171,9 +171,10 @@ HTMLTreeBuilderSimulator::SimulatedToken HTMLTreeBuilderSimulator::Simulate(
           language_attribute_value = item->Value();
         }
 
-        if (ScriptLoader::IsValidScriptTypeAndLanguage(
+        if (ScriptLoader::GetScriptTypeAtPrepare(
                 type_attribute_value, language_attribute_value,
-                ScriptLoader::kAllowLegacyTypeInTypeAttribute)) {
+                ScriptLoader::kAllowLegacyTypeInTypeAttribute) !=
+            ScriptLoader::ScriptTypeAtPrepare::kInvalid) {
           simulated_token = kValidScriptStart;
         }
       } else if (ThreadSafeMatch(tag_name, html_names::kLinkTag)) {

third_party/blink/renderer/core/script/script_loader.h

@@ -61,19 +61,17 @@ class CORE_EXPORT ScriptLoader final : public GarbageCollected<ScriptLoader>,
     kAllowLegacyTypeInTypeAttribute
   };
 
-  // |out_is_import_map| is set separately from |out_script_type| in order
-  // to avoid adding import maps as a mojom::blink::ScriptType enum, because
-  // import maps are processed quite differently from classic/module scripts.
-  //
-  // TODO(hiroshige, kouhei): Make the method signature simpler.
-  static bool IsValidScriptTypeAndLanguage(
+  // Script type at the time of #prepare-a-script. Import maps are included here
+  // but not in `mojom::blink::ScriptType` because import maps are handled
+  // differently from ordinal scripts after PrepareScript().
+  enum class ScriptTypeAtPrepare { kClassic, kModule, kImportMap, kInvalid };
+
+  static ScriptTypeAtPrepare GetScriptTypeAtPrepare(
       const String& type_attribute_value,
       const String& language_attribute_value,
-      LegacyTypeSupport support_legacy_types,
-      mojom::blink::ScriptType* out_script_type = nullptr,
-      bool* out_is_import_map = nullptr);
+      LegacyTypeSupport support_legacy_types);
 
-  static bool BlockForNoModule(mojom::blink::ScriptType, bool nomodule);
+  static bool BlockForNoModule(ScriptTypeAtPrepare, bool nomodule);
 
   static network::mojom::CredentialsMode ModuleScriptCredentialsMode(
       CrossOriginAttributeValue);
@@ -97,7 +95,7 @@ class CORE_EXPORT ScriptLoader final : public GarbageCollected<ScriptLoader>,
   bool IsParserInserted() const { return parser_inserted_; }
   bool AlreadyStarted() const { return already_started_; }
   bool IsNonBlocking() const { return non_blocking_; }
-  mojom::blink::ScriptType GetScriptType() const { return script_type_; }
+  ScriptTypeAtPrepare GetScriptType() const { return script_type_; }
 
   // Helper functions used by our parent classes.
   void DidNotifySubtreeInsertionsToDocument();
@@ -178,7 +176,7 @@ class CORE_EXPORT ScriptLoader final : public GarbageCollected<ScriptLoader>,
 
   // <spec href="https://html.spec.whatwg.org/C/#concept-script-type">... It is
   // determined when the script is prepared, ...</spec>
-  mojom::blink::ScriptType script_type_ = mojom::blink::ScriptType::kClassic;
+  ScriptTypeAtPrepare script_type_ = ScriptTypeAtPrepare::kInvalid;
 
   // <spec href="https://html.spec.whatwg.org/C/#concept-script-external">
   // ... It is determined when the script is prepared, ...</spec>

third_party/blink/renderer/core/script/xml_parser_script_runner.cc

@@ -77,7 +77,8 @@ void XMLParserScriptRunner::ProcessScriptElement(
   bool success = script_loader->PrepareScript(
       script_start_position, ScriptLoader::kAllowLegacyTypeInTypeAttribute);
 
-  if (script_loader->GetScriptType() != mojom::blink::ScriptType::kClassic) {
+  if (script_loader->GetScriptType() ==
+      ScriptLoader::ScriptTypeAtPrepare::kModule) {
     // XMLDocumentParser does not support a module script, and thus ignores it.
     success = false;
     document.AddConsoleMessage(MakeGarbageCollected<ConsoleMessage>(