Clean up includes and forward-declarations in the flowthread / multicol files.

Source/core/rendering/RenderRegion.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 12 matching lines @@
  * 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 "config.h"
 #include "core/rendering/RenderRegion.h"
 
-#include "core/css/resolver/StyleResolver.h"
-#include "core/rendering/FlowThreadController.h"
-#include "core/rendering/HitTestLocation.h"
-#include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderFlowThread.h"
-#include "core/rendering/RenderView.h"
 
 namespace blink {
 
 RenderRegion::RenderRegion(Element* element, RenderFlowThread* flowThread)
     : RenderBlockFlow(element)
     , m_flowThread(flowThread)
     , m_isValid(false)
 {
 }
 
@@ skipping 99 matching lines @@
     if (!isValid()) {
         RenderBlockFlow::computeIntrinsicLogicalWidths(minLogicalWidth, maxLogicalWidth);
         return;
     }
 
     minLogicalWidth = m_flowThread->minPreferredLogicalWidth();
     maxLogicalWidth = m_flowThread->maxPreferredLogicalWidth();
 }
 
 } // namespace blink