Remove UserAgent ShadowRoot + Author ShadowRoot code.

third_party/WebKit/Source/core/html/HTMLPlugInElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  *
  * 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.
  *
@@ skipping 98 matching lines @@
     void attach(const AttachContext& = AttachContext()) final;
     void detach(const AttachContext& = AttachContext()) final;
     void finishParsingChildren() final;
 
     // Element functions:
     LayoutObject* createLayoutObject(const ComputedStyle&) override;
     bool supportsFocus() const final { return true; }
     bool layoutObjectIsFocusable() const final;
     bool isKeyboardFocusable() const final;
     void didAddUserAgentShadowRoot(ShadowRoot&) final;
-    void willAddFirstAuthorShadowRoot() final;
 
     // HTMLElement function:
     bool hasCustomFocusLogic() const override;
     bool isPluginElement() const final;
 
     // Return any existing LayoutPart without triggering relayout, or 0 if it
     // doesn't yet exist.
     virtual LayoutPart* existingLayoutPart() const = 0;
     virtual void updateWidgetInternal() = 0;
 
@@ skipping 22 matching lines @@
 inline bool isHTMLPlugInElement(const HTMLElement& element)
 {
     return element.isPluginElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLPlugInElement);
 
 } // namespace blink
 
 #endif // HTMLPlugInElement_h