Allow multiple dart <script> tags in .sky files

sky/engine/core/app/AbstractModule.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SKY_ENGINE_CORE_APP_ABSTRACTMODULE_H_
 #define SKY_ENGINE_CORE_APP_ABSTRACTMODULE_H_
 
 #include "sky/engine/core/dom/ContextLifecycleObserver.h"
 #include "sky/engine/core/dom/Document.h"
 #include "sky/engine/core/events/EventTarget.h"
 #include "sky/engine/wtf/RefCounted.h"
 
 namespace blink {
 class Application;
 
+class LibraryEntry {
+ public:
+  LibraryEntry(PassRefPtr<DartValue> library, TextPosition position)
+      : dart_library_(library), text_position_(position) {}
+
+  DartValue* library() const { return dart_library_.get(); }
+  const TextPosition& position() const { return text_position_; }
+
+ private:
+  RefPtr<DartValue> dart_library_;
+  TextPosition text_position_;
+};
+
 class AbstractModule : public RefCounted<AbstractModule>,
                        public EventTargetWithInlineData,
                        public ContextLifecycleObserver {
   REFCOUNTED_EVENT_TARGET(AbstractModule);
  public:
   virtual ~AbstractModule();
 
   Document* document() const { return document_.get(); }
   const String& url() const { return url_; }
 
   virtual bool isApplication() const { return false; }
 
-  void set_library(RefPtr<DartValue> library) { library_ = library; }
+  String UrlForLibraryAt(TextPosition);
 
-  DartValue* library() const { return library_.get(); }
+  void AddLibrary(RefPtr<DartValue> library, TextPosition position);
+  const Vector<LibraryEntry>& libraries() const { return libraries_; }
 
  protected:
   AbstractModule(ExecutionContext*, PassRefPtr<Document>, const String& url);
 
   virtual Application* GetApplication() = 0;
 
  private:
   ExecutionContext* executionContext() const override;
 
   RefPtr<Document> document_;
   String url_;
-  RefPtr<DartValue> library_;
+  Vector<LibraryEntry> libraries_;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_APP_ABSTRACTMODULE_H_