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

third_party/WebKit/Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 49 matching lines @@
 #include "core/frame/Settings.h"
 #include "core/html/HTMLBodyElement.h"
 #include "core/html/HTMLFormElement.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLSelectElement.h"
 #include "core/input/EventHandler.h"
 #include "core/layout/HitTestRequest.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutPart.h"
+#include "core/layout/api/LayoutViewItem.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/page/EditorClient.h"
 #include "core/page/FocusController.h"
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/SpatialNavigation.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/SecureTextInput.h"
 #include "platform/geometry/FloatQuad.h"
 #include "platform/graphics/GraphicsContext.h"
@@ skipping 1298 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         LOG(INFO) << "Cannot showTree for <null> FrameSelection.";
 }
 
 #endif