LayoutFullScreen::m_placeholder is LayoutBlockFlow.

third_party/WebKit/Source/core/dom/Fullscreen.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 24 matching lines @@
 #include "core/events/Event.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/OriginsUsingFeatures.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/input/EventHandler.h"
 #include "core/inspector/ConsoleMessage.h"
+#include "core/layout/LayoutBlockFlow.h"
 #include "core/layout/LayoutFullScreen.h"
 #include "core/layout/api/LayoutFullScreenItem.h"
 #include "core/page/ChromeClient.h"
 #include "platform/UserGestureIndicator.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 static bool fullscreenIsAllowedForAllOwners(const Document& document)
@@ skipping 436 matching lines @@
 }
 
 void Fullscreen::setFullScreenLayoutObject(LayoutFullScreen* layoutObject)
 {
     if (layoutObject == m_fullScreenLayoutObject)
         return;
 
     if (layoutObject && m_savedPlaceholderComputedStyle) {
         layoutObject->createPlaceholder(m_savedPlaceholderComputedStyle.release(), m_savedPlaceholderFrameRect);
     } else if (layoutObject && m_fullScreenLayoutObject && m_fullScreenLayoutObject->placeholder()) {
-        LayoutBlock* placeholder = m_fullScreenLayoutObject->placeholder();
+        LayoutBlockFlow* placeholder = m_fullScreenLayoutObject->placeholder();
         layoutObject->createPlaceholder(ComputedStyle::clone(placeholder->styleRef()), placeholder->frameRect());
     }
 
     if (m_fullScreenLayoutObject)
         m_fullScreenLayoutObject->unwrapLayoutObject();
     DCHECK(!m_fullScreenLayoutObject);
 
     m_fullScreenLayoutObject = layoutObject;
 }
 
@@ skipping 95 matching lines @@
 DEFINE_TRACE(Fullscreen)
 {
     visitor->trace(m_fullScreenElement);
     visitor->trace(m_fullScreenElementStack);
     visitor->trace(m_eventQueue);
     Supplement<Document>::trace(visitor);
     ContextLifecycleObserver::trace(visitor);
 }
 
 } // namespace blink