Extract tree root responsibility out of HTMLImportsController.

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 19 matching lines @@
 
 #include "config.h"
 #include "core/html/imports/HTMLImportChild.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementMicrotaskDispatcher.h"
 #include "core/dom/custom/CustomElementMicrotaskImportStep.h"
 #include "core/html/imports/HTMLImportChildClient.h"
 #include "core/html/imports/HTMLImportLoader.h"
+#include "core/html/imports/HTMLImportTreeRoot.h"
 #include "core/html/imports/HTMLImportsController.h"
 
 namespace WebCore {
 
 HTMLImportChild::HTMLImportChild(const KURL& url, HTMLImportLoader* loader, SyncMode sync)
     : HTMLImport(sync)
     , m_url(url)
     , m_weakFactory(this)
     , m_loader(loader)
     , m_client(0)
@@ skipping 66 matching lines @@
     }
 }
 
 Document* HTMLImportChild::document() const
 {
     return m_loader ? m_loader->document() : 0;
 }
 
 void HTMLImportChild::stateWillChange()
 {
-    toHTMLImportsController(root())->scheduleRecalcState();
+    toHTMLImportTreeRoot(root())->scheduleRecalcState();
 }
 
 void HTMLImportChild::stateDidChange()
 {
     HTMLImport::stateDidChange();
 
     if (state().isReady())
         didFinish();
 }
 
@@ skipping 74 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