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

third_party/WebKit/Source/core/layout/LayoutPart.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  *           (C) 2000 Stefan Schimanski (1Stein@gmx.de)
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. 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
@@ skipping 14 matching lines @@
 #include "core/layout/LayoutPart.h"
 
 #include "core/dom/AXObjectCache.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutAnalyzer.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutAPIShim.h"
+#include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/PartPainter.h"
 #include "core/plugins/PluginView.h"
 
 namespace blink {
 
 LayoutPart::LayoutPart(Element* element)
     : LayoutReplaced(element)
     // Reference counting is used to prevent the part from being destroyed
     // while inside the Widget code, which might not be able to handle that.
     , m_refCount(1)
@@ skipping 324 matching lines @@
 
 bool LayoutPart::isThrottledFrameView() const
 {
     if (!widget() || !widget()->isFrameView())
         return false;
     const FrameView* frameView = toFrameView(widget());
     return frameView->shouldThrottleRendering();
 }
 
 } // namespace blink