Re-attach renderer for progress/meter when author shadow is allowed.

Source/core/html/HTMLMeterElement.h

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 51 matching lines @@
 
     virtual bool canContainRangeEndPoint() const override { return false; }
 
     virtual void trace(Visitor*) override;
 
 private:
     explicit HTMLMeterElement(Document&);
     virtual ~HTMLMeterElement();
 
     virtual bool areAuthorShadowsAllowed() const override { return false; }
+    virtual void willAddFirstAuthorShadowRoot() override;
     RenderMeter* renderMeter() const;
 
     virtual bool supportLabels() const override { return true; }
 
     virtual LayoutObject* createRenderer(const RenderStyle&) override;
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
 
     void didElementStateChange();
     virtual void didAddUserAgentShadowRoot(ShadowRoot&) override;
 
     RefPtrWillBeMember<MeterValueElement> m_value;
 };
 
 } // namespace blink
 
 #endif // HTMLMeterElement_h