Remove unnecessary includes of LayoutBlock-derived headers.

third_party/WebKit/Source/core/paint/PaintLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 44 matching lines @@
 #include "core/html/HTMLFrameElement.h"
 #include "core/layout/HitTestRequest.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/HitTestingTransformState.h"
 #include "core/layout/LayoutFlowThread.h"
 #include "core/layout/LayoutGeometryMap.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/LayoutReplica.h"
 #include "core/layout/LayoutScrollbar.h"
-#include "core/layout/LayoutScrollbarPart.h"
 #include "core/layout/LayoutTreeAsText.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/CompositedLayerMapping.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/layout/svg/LayoutSVGResourceClipper.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/layout/svg/ReferenceFilterBuilder.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/BoxReflectionUtils.h"
@@ skipping 2837 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif