Fix redrawing of a composited element with a filter.

Source/core/rendering/style/RenderStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 568 matching lines @@
 
     // If the counter directives change, trigger a relayout to re-calculate counter values and rebuild the counter node tree.
     const CounterDirectiveMap* mapA = rareNonInheritedData->m_counterDirectives.get();
     const CounterDirectiveMap* mapB = other->rareNonInheritedData->m_counterDirectives.get();
     if (!(mapA == mapB || (mapA && mapB && *mapA == *mapB)))
         return StyleDifferenceLayout;
 
     if ((visibility() == COLLAPSE) != (other->visibility() == COLLAPSE))
         return StyleDifferenceLayout;
 
-    if ((rareNonInheritedData->opacity == 1 && other->rareNonInheritedData->opacity < 1)
-        || (rareNonInheritedData->opacity < 1 && other->rareNonInheritedData->opacity == 1)) {
+    if (rareNonInheritedData->hasOpacity() != other->rareNonInheritedData->hasOpacity()) {
         // FIXME: We would like to use SimplifiedLayout here, but we can't quite do that yet.
         // We need to make sure SimplifiedLayout can operate correctly on RenderInlines (we will need
         // to add a selfNeedsSimplifiedLayout bit in order to not get confused and taint every line).
         // In addition we need to solve the floating object issue when layers come and go. Right now
         // a full layout is necessary to keep floating object lists sane.
         return StyleDifferenceLayout;
     }
 
+    if (rareNonInheritedData->hasFilters() != other->rareNonInheritedData->hasFilters())
+        return StyleDifferenceLayout;
+
     if (!QuotesData::equals(rareInheritedData->quotes.get(), other->rareInheritedData->quotes.get()))
         return StyleDifferenceLayout;
 
     // SVGRenderStyle::diff() might have returned StyleDifferenceRepaint, eg. if fill changes.
     // If eg. the font-size changed at the same time, we're not allowed to return StyleDifferenceRepaint,
     // but have to return StyleDifferenceLayout, that's why  this if branch comes after all branches
     // that are relevant for SVG and might return StyleDifferenceLayout.
     if (svgChange != StyleDifferenceEqual)
         return svgChange;
 
@@ skipping 994 matching lines @@
     surround.access()->border.m_image.setOutset(outset);
 }
 
 ShapeValue* RenderStyle::initialShapeInside()
 {
     DEFINE_STATIC_LOCAL(RefPtr<ShapeValue>, sOutsideValue, (ShapeValue::createOutsideValue()));
     return sOutsideValue.get();
 }
 
 } // namespace WebCore