[WIP Prototype] ES6 https://html.spec.whatwg.org/#fetch-a-single-module-script implementation

third_party/WebKit/Source/core/dom/ScriptLoader.cpp

Index: third_party/WebKit/Source/core/dom/ScriptLoader.cpp
diff --git a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
index a02e2ca2086a275cb4d1cf3ef5647e11e0236ce3..cafd04a047a2320ae27dee55890cd29982081d78 100644
--- a/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
+++ b/third_party/WebKit/Source/core/dom/ScriptLoader.cpp
@@ -34,6 +34,7 @@
 #include "core/dom/ScriptLoaderClient.h"
 #include "core/dom/ScriptRunner.h"
 #include "core/dom/ScriptableDocumentParser.h"
+#include "core/dom/ModuleMap.h"
 #include "core/dom/Text.h"
 #include "core/events/Event.h"
 #include "core/fetch/AccessControlStatus.h"
@@ -260,6 +261,7 @@ bool ScriptLoader::prepareScript(const TextPosition& scriptStartPosition,
     if (m_documentWriteIntervention ==
         DocumentWriteIntervention::FetchDocWrittenScriptDeferIdle)
       defer = FetchRequest::IdleLoad;
+
     if (!fetchScript(client->sourceAttributeValue(), defer))
       return false;
   }
@@ -335,10 +337,17 @@ bool ScriptLoader::fetchScript(const String& sourceUrl,
     return false;
 
   DCHECK(!m_resource);
+
   if (!stripLeadingAndTrailingHTMLSpaces(sourceUrl).isEmpty()) {
-    FetchRequest request(
-        ResourceRequest(elementDocument->completeURL(sourceUrl)),
-        m_element->localName());
+    KURL url = elementDocument->completeURL(sourceUrl);
+
+    if (RuntimeEnabledFeatures::moduleScriptsEnabled() &&
+        client()->typeAttributeValue() == "module") {
+      elementDocument->ensureModuleMap()->fetch(url);
+      return true;
+    }
+
+    FetchRequest request(ResourceRequest(url), m_element->localName());
 
     CrossOriginAttributeValue crossOrigin = crossOriginAttributeValue(
         m_element->fastGetAttribute(HTMLNames::crossoriginAttr));