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

third_party/WebKit/Source/modules/accessibility/AXObject.cpp

 /*
  * Copyright (C) 2008, 2009, 2011 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
@@ skipping 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "modules/accessibility/AXObject.h"
 
 #include "SkMatrix44.h"
+#include "core/css/resolver/StyleResolver.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
+#include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutTheme.h"
 #include "modules/accessibility/AXObjectCacheImpl.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/text/PlatformLocale.h"
 #include "wtf/HashSet.h"
 #include "wtf/StdLibExtras.h"
 #include "wtf/text/WTFString.h"
 
 using blink::WebLocalizedString;
@@ skipping 1766 matching lines @@
 
 DEFINE_TRACE(AXObject)
 {
     visitor->trace(m_children);
     visitor->trace(m_parent);
     visitor->trace(m_cachedLiveRegionRoot);
     visitor->trace(m_axObjectCache);
 }
 
 } // namespace blink