Include Event.h in fewer header files

Source/core/html/HTMLDetailsElement.cpp

 /*
  * Copyright (C) 2010, 2011 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "config.h"
 #include "core/html/HTMLDetailsElement.h"
 
 #include "bindings/v8/ExceptionStatePlaceholder.h"
 #include "core/CSSPropertyNames.h"
 #include "core/CSSValueKeywords.h"
 #include "core/HTMLNames.h"
 #include "core/dom/Text.h"
 #include "core/dom/shadow/ShadowRoot.h"
+#include "core/events/Event.h"
 #include "core/events/EventSender.h"
 #include "core/html/HTMLContentElement.h"
 #include "core/html/HTMLDivElement.h"
 #include "core/html/HTMLSummaryElement.h"
 #include "core/html/shadow/ShadowElementNames.h"
 #include "core/rendering/RenderBlockFlow.h"
 #include "platform/text/PlatformLocale.h"
 
 namespace WebCore {
 
@@ skipping 99 matching lines @@
 {
     setAttribute(openAttr, m_isOpen ? nullAtom : emptyAtom);
 }
 
 bool HTMLDetailsElement::isInteractiveContent() const
 {
     return true;
 }
 
 }