Make custom elements work in HTML imports

third_party/WebKit/Source/core/html/imports/HTMLImportTreeRoot.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef HTMLImportTreeRoot_h
 #define HTMLImportTreeRoot_h
 
 #include "core/html/imports/HTMLImport.h"
 #include "platform/Timer.h"
 
@@ skipping 12 matching lines @@
     // HTMLImport
     Document* document() const override;
     bool hasFinishedLoading() const override;
     void stateWillChange() override;
     void stateDidChange() override;
 
     void scheduleRecalcState();
 
     HTMLImportChild* add(HTMLImportChild*);
     HTMLImportChild* find(const KURL&) const;
+    HTMLImportChild* find(const Document&) const;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit HTMLImportTreeRoot(Document*);
 
     void recalcTimerFired(TimerBase*);
 
     Member<Document> m_document;
     Timer<HTMLImportTreeRoot> m_recalcTimer;
 
     // List of import which has been loaded or being loaded.
     typedef HeapVector<Member<HTMLImportChild>> ImportList;
     ImportList m_imports;
 };
 
 DEFINE_TYPE_CASTS(HTMLImportTreeRoot, HTMLImport, import, import->isRoot(), import.isRoot());
 
 } // namespace blink
 
 #endif