HTMLImportsController does not need to hold Document ptr.

Source/core/html/LinkResource.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 37 matching lines @@
 {
 }
 
 bool LinkResource::shouldLoadResource() const
 {
     return m_owner->document().frame() || m_owner->document().importsController();
 }
 
 LocalFrame* LinkResource::loadingFrame() const
 {
-    HTMLImportsController* import = m_owner->document().importsController();
-    if (!import)
+    HTMLImportsController* importsController = m_owner->document().importsController();
+    if (!importsController)
         return m_owner->document().frame();
-    return import->frame();
+    return importsController->master()->frame();
 }
 
 void LinkResource::trace(Visitor* visitor)
 {
     visitor->trace(m_owner);
 }
 
 LinkRequestBuilder::LinkRequestBuilder(HTMLLinkElement* owner)
     : m_owner(owner)
     , m_url(owner->getNonEmptyURLAttribute(hrefAttr))
 {
     m_charset = m_owner->getAttribute(charsetAttr);
     if (m_charset.isEmpty() && m_owner->document().frame())
         m_charset = m_owner->document().charset();
 }
 
 FetchRequest LinkRequestBuilder::build(bool blocking) const
 {
     ResourceLoadPriority priority = blocking ? ResourceLoadPriorityUnresolved : ResourceLoadPriorityVeryLow;
     return FetchRequest(ResourceRequest(m_owner->document().completeURL(m_url)), m_owner->localName(), m_charset, priority);
 }
 
 } // namespace WebCore