Let ContentSecurityPolicy shared between imports and the master.

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 21 matching lines @@
 #include "core/html/imports/HTMLImportChild.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementMicrotaskImportStep.h"
 #include "core/html/imports/HTMLImportChildClient.h"
 #include "core/html/imports/HTMLImportLoader.h"
 
 namespace WebCore {
 
-HTMLImportChild::HTMLImportChild(const KURL& url, bool createdByParser)
+HTMLImportChild::HTMLImportChild(Document& master, const KURL& url, bool createdByParser)
     : HTMLImport(createdByParser)
+    , m_master(master)
     , m_url(url)
     , m_customElementMicrotaskStep(0)
     , m_client(0)
 {
+    m_master.guardRef();
 }
 
 HTMLImportChild::~HTMLImportChild()
 {
     // importDestroyed() should be called before the destruction.
     ASSERT(!m_loader);
 
     if (m_customElementMicrotaskStep) {
         // if Custom Elements were blocked, must unblock them before death
         m_customElementMicrotaskStep->importDidFinish();
         m_customElementMicrotaskStep = 0;
     }
 
     if (m_client)
         m_client->importChildWasDestroyed(this);
+
+    m_master.guardDeref();
 }
 
 void HTMLImportChild::wasAlreadyLoaded()
 {
     ASSERT(!m_loader);
     ASSERT(m_client);
     stateWillChange();
 }
 
 void HTMLImportChild::startLoading(const ResourcePtr<RawResource>& resource)
@@ skipping 165 matching lines @@
     HTMLImport::showThis();
     fprintf(stderr, " loader=%p own=%s async=%s url=%s",
         m_loader.get(),
         hasLoader() && ownsLoader() ? "Y" : "N",
         isCreatedByParser() ? "Y" : "N",
         url().string().utf8().data());
 }
 #endif
 
 } // namespace WebCore