Avoid leaking ThreadingPrimitives.h from StackStats.h when collection is off.

Source/core/rendering/RenderObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 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
@@ skipping 22 matching lines @@
 #include "core/platform/graphics/FloatQuad.h"
 #include "core/platform/graphics/LayoutRect.h"
 #include "core/platform/graphics/transforms/TransformationMatrix.h"
 #include "core/rendering/PaintPhase.h"
 #include "core/rendering/RenderObjectChildList.h"
 #include "core/rendering/ScrollBehavior.h"
 #include "core/rendering/SubtreeLayoutScope.h"
 #include "core/rendering/style/RenderStyle.h"
 #include "core/rendering/style/StyleInheritedData.h"
 #include "wtf/HashSet.h"
-#include "wtf/StackStats.h"
-#include "wtf/UnusedParam.h"
 
 namespace WebCore {
 
 class AffineTransform;
 class AnimationController;
 class Cursor;
 class Document;
 class HitTestLocation;
 class HitTestResult;
 class InlineBox;
@@ skipping 1340 matching lines @@
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::RenderObject*);
 void showLineTree(const WebCore::RenderObject*);
 void showRenderTree(const WebCore::RenderObject* object1);
 // We don't make object2 an optional parameter so that showRenderTree
 // can be called from gdb easily.
 void showRenderTree(const WebCore::RenderObject* object1, const WebCore::RenderObject* object2);
 #endif
 
 #endif // RenderObject_h