Centralize TextStream functions to remove RenderTreeAsText dependency of the filters

Source/core/platform/graphics/filters/FEMerge.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 10 matching lines @@
  */
 
 #include "config.h"
 
 #include "core/platform/graphics/filters/FEMerge.h"
 
 #include "SkMergeImageFilter.h"
 #include "core/platform/graphics/GraphicsContext.h"
 #include "core/platform/graphics/filters/Filter.h"
 #include "core/platform/graphics/filters/SkiaImageFilterBuilder.h"
-#include "core/rendering/RenderTreeAsText.h"
 #include "platform/text/TextStream.h"
 #include "wtf/OwnPtr.h"
 
 namespace WebCore {
 
 FEMerge::FEMerge(Filter* filter)
     : FilterEffect(filter)
 {
 }
 
@@ skipping 39 matching lines @@
     FilterEffect::externalRepresentation(ts);
     unsigned size = numberOfEffectInputs();
     ASSERT(size > 0);
     ts << " mergeNodes=\"" << size << "\"]\n";
     for (unsigned i = 0; i < size; ++i)
         inputEffect(i)->externalRepresentation(ts, indent + 1);
     return ts;
 }
 
 } // namespace WebCore