Don't include headers from the layout API from other headers needlessly.

third_party/WebKit/Source/core/frame/Frame.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 22 matching lines @@
 #include "core/events/Event.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/input/EventHandler.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InstanceCounters.h"
 #include "core/layout/LayoutPart.h"
+#include "core/layout/api/LayoutPartItem.h"
 #include "core/loader/EmptyClients.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/loader/NavigationScheduler.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "platform/Histogram.h"
 #include "platform/UserGestureIndicator.h"
 
 namespace blink {
 
@@ skipping 225 matching lines @@
         return nullptr;
     // FIXME: If <object> is ever fixed to disassociate itself from frames
     // that it has started but canceled, then this can turn into an ASSERT
     // since ownerElement() would be 0 when the load is canceled.
     // https://bugs.webkit.org/show_bug.cgi?id=18585
     if (!object->isLayoutPart())
         return nullptr;
     return toLayoutPart(object);
 }
 
+LayoutPartItem Frame::ownerLayoutItem() const
+{
+    return LayoutPartItem(ownerLayoutObject());
+}
+
 Settings* Frame::settings() const
 {
     if (m_host)
         return &m_host->settings();
     return nullptr;
 }
 
 void Frame::didChangeVisibilityState()
 {
     HeapVector<Member<Frame>> childFrames;
@@ skipping 14 matching lines @@
 
     ASSERT(page());
 
     if (m_owner)
         m_owner->setContentFrame(*this);
     else
         page()->setMainFrame(this);
 }
 
 } // namespace blink