Reland HTMLPlugInElement: Use custom focus logic only when there is a plugin.

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 34 matching lines @@
 class HTMLPlugInElement : public HTMLFrameOwnerElement {
 public:
     virtual ~HTMLPlugInElement();
     virtual void trace(Visitor*) override;
 #if ENABLE(OILPAN)
     virtual void disconnectContentFrame() override;
     void shouldDisposePlugin();
 #endif
 
     void resetInstance();
+
+    // Returns the existing plugin widget, if there is one.
+    Widget* existingPluginWidget() const;
+
+    // Returns the plugin widget, forcing layout and post-layout tasks
+    // to happen synchronously (e.g. for JS bindings).
+    // See also renderPartForJSBindings().
+    Widget* pluginWidgetForJSBindings();
+
     SharedPersistent<v8::Object>* pluginWrapper();
-    Widget* pluginWidget() const;
     NPObject* getNPObject();
     bool canProcessDrag() const;
     const String& url() const { return m_url; }
 
     // Public for FrameView::addPartToUpdate()
     bool needsWidgetUpdate() const { return m_needsWidgetUpdate; }
     void setNeedsWidgetUpdate(bool needsWidgetUpdate) { m_needsWidgetUpdate = needsWidgetUpdate; }
     void updateWidget();
 
     bool shouldAccelerate() const;
@@ skipping 91 matching lines @@
 inline bool isHTMLPlugInElement(const HTMLElement& element)
 {
     return element.isPluginElement();
 }
 
 DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLPlugInElement);
 
 } // namespace blink
 
 #endif // HTMLPlugInElement_h