Remove background obscuration checks.

sky/engine/core/rendering/RenderReplaced.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011-2012. 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 59 matching lines @@
     ASSERT(needsLayout());
 
     setHeight(minimumReplacedHeight());
 
     updateLogicalWidth();
     updateLogicalHeight();
 
     m_overflow.clear();
     addVisualEffectOverflow();
     updateLayerTransformAfterLayout();
-    invalidateBackgroundObscurationStatus();
 
     clearNeedsLayout();
 }
 
 void RenderReplaced::intrinsicSizeChanged()
 {
     m_intrinsicSize = IntSize(defaultWidth, defaultHeight);
     setNeedsLayoutAndPrefWidthsRecalc();
 }
 
@@ skipping 393 matching lines @@
     if (s == SelectionEnd)
         return selectionEnd == end;
     if (s == SelectionBoth)
         return selectionStart == 0 && selectionEnd == end;
 
     ASSERT(0);
     return false;
 }
 
 }