Remove the importedDocument functions from HTML imports classes.

Source/core/html/imports/HTMLImportChild.cpp

 /*
  * 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 82 matching lines @@
 bool HTMLImportChild::isLoaded() const
 {
     return m_loader && m_loader->isDone();
 }
 
 bool HTMLImportChild::isFirst() const
 {
     return m_loader && m_loader->isFirstImport(this);
 }
 
-Document* HTMLImportChild::importedDocument() const
-{
-    if (!m_loader)
-        return 0;
-    return m_loader->importedDocument();
-}
-
 void HTMLImportChild::importDestroyed()
 {
     if (parent())
         parent()->removeChild(this);
     if (m_loader) {
         m_loader->removeImport(this);
         m_loader = 0;
     }
 }
 
@@ skipping 92 matching lines @@
     fprintf(stderr, " loader=%p first=%d, step=%p sync=%s url=%s",
         m_loader,
         isFirst,
         m_customElementMicrotaskStep.get(),
         isSync() ? "Y" : "N",
         url().string().utf8().data());
 }
 #endif
 
 } // namespace WebCore