Script-based imports should basically work

sky/engine/core/app/AbstractModule.h

Index: sky/engine/core/app/AbstractModule.h
diff --git a/sky/engine/core/app/AbstractModule.h b/sky/engine/core/app/AbstractModule.h
index fc65261df2f8ae01a9f7faf56b481aeb4c6d5057..d9ece5a8cb93fff60328619650bc9729cf0e1e1b 100644
--- a/sky/engine/core/app/AbstractModule.h
+++ b/sky/engine/core/app/AbstractModule.h
@@ -5,16 +5,20 @@
 #ifndef SKY_ENGINE_CORE_APP_ABSTRACT_MODULE_H_
 #define SKY_ENGINE_CORE_APP_ABSTRACT_MODULE_H_
 
+#include "bindings/core/v8/ScriptPromiseResolver.h"
+#include "core/app/ModuleLoader.h"
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/dom/Document.h"
 #include "core/events/EventTarget.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
+class Application;
 
 class AbstractModule : public RefCounted<AbstractModule>,
                        public EventTargetWithInlineData,
-                       public ContextLifecycleObserver {
+                       public ContextLifecycleObserver,
+                       public ModuleLoader::Client {
   DEFINE_WRAPPERTYPEINFO();
   REFCOUNTED_EVENT_TARGET(AbstractModule);
  public:
@@ -23,14 +27,22 @@ class AbstractModule : public RefCounted<AbstractModule>,
   Document* document() const { return document_.get(); }
   const String& url() const { return url_; }
 
+  ScriptPromise import(ScriptState*, const String& url);
+
  protected:
   AbstractModule(ExecutionContext*, PassRefPtr<Document>, const String& url);
 
+  virtual Application* GetApplication() = 0;
+
  private:
   ExecutionContext* executionContext() const override;
 
+  void OnModuleLoadComplete(ModuleLoader*, Module*) override;
+
   RefPtr<Document> document_;
   String url_;
+
+  HashMap<OwnPtr<ModuleLoader>, RefPtr<ScriptPromiseResolver>> loaders_;
 };
 
 } // namespace blink