Remove obsolete FIXME that no longer applies for blink rendering architecture

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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 2024 matching lines @@
 
             if (layer() && layer()->transform())
                 rect = layer()->transform()->mapRect(pixelSnappedIntRect(rect));
 
             // We can't trust the bits on RenderObject, because this might be called while re-resolving style.
             if (styleToUse->hasInFlowPosition() && layer())
                 rect.move(layer()->offsetForInFlowPosition());
 
             rect.moveBy(location());
             rect.move(layoutState->m_paintOffset);
-            if (layoutState->m_clipped)
+            if (layoutState->m_clipped && !rect.isEmpty())

[eseidel, 2014/03/11 18:24:30]

I'm surprised this is necessary?  Doesn't rect.intersect already early-out when
one of them is empty?

                 rect.intersect(layoutState->m_clipRect);
             return;
         }
     }
 
     if (hasReflection())
         rect.unite(reflectedRect(rect));
 
     if (repaintContainer == this) {
         if (repaintContainer->style()->isFlippedBlocksWritingMode())
@@ skipping 2636 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore