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

Source/core/rendering/RenderFlowThread.h

 /*
  * 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.
  */
 
 #ifndef RenderFlowThread_h
 #define RenderFlowThread_h
 
-
+#include "core/rendering/LayerFragment.h"
 #include "core/rendering/RenderBlockFlow.h"
-#include "wtf/HashCountedSet.h"
 #include "wtf/ListHashSet.h"
-#include "wtf/PassRefPtr.h"
 
 namespace blink {
 
-struct LayerFragment;
-typedef Vector<LayerFragment, 1> LayerFragments;
-class RenderFlowThread;
 class RenderMultiColumnSet;
 class RenderRegion;
 
 typedef ListHashSet<RenderMultiColumnSet*> RenderMultiColumnSetList;
 
 // RenderFlowThread is used to collect all the render objects that participate in a
 // flow thread. It will also help in doing the layout. However, it will not render
 // directly to screen. Instead, RenderRegion objects will redirect their paint
 // and nodeAtPoint methods to this object. Each RenderRegion will actually be a viewPort
 // of the RenderFlowThread.
@@ skipping 133 matching lines @@
 };
 
 template <> struct ValueToString<RenderMultiColumnSet*> {
     static String string(const RenderMultiColumnSet* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace blink
 
 #endif // RenderFlowThread_h