HTML Imports: Make sure new imports being added to the "first child"

Source/core/html/imports/HTMLImportLoader.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 55 matching lines @@
     {
         return adoptRef(new HTMLImportLoader(controller));
     }
 
     virtual ~HTMLImportLoader();
 
     Document* document() const { return m_importedDocument.get(); }
     Document* importedDocument() const;
     void addImport(HTMLImportChild*);
     void removeImport(HTMLImportChild*);
+    void moveToFirst(HTMLImportChild*);
     HTMLImportChild* firstImport() const { return m_imports[0]; }
+    bool isFirstImport(HTMLImportChild* child) const { return m_imports.size() ? firstImport() == child : false; }
 
     bool isDone() const { return m_state == StateLoaded || m_state == StateError; }
     bool hasError() const { return m_state == StateError; }
     bool shouldBlockScriptExecution() const;
 
     void importDestroyed();
     void startLoading(const ResourcePtr<RawResource>&);
     void didFinishParsing();
     void didRemoveAllPendingStylesheet();
 
@@ skipping 21 matching lines @@
     Vector<HTMLImportChild*> m_imports;
     State m_state;
     RefPtr<Document> m_importedDocument;
     RefPtr<DocumentWriter> m_writer;
     RefPtr<CustomElementMicrotaskQueue> m_microtaskQueue;
 };
 
 } // namespace WebCore
 
 #endif // HTMLImportLoader_h