Simplify the paint invalidation bits.

sky/engine/core/rendering/RenderLayerModelObject.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 Apple Inc. All rights reserved.
  * Copyright (C) 2010, 2012 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 58 matching lines @@
 
 void RenderLayerModelObject::willBeDestroyed()
 {
     RenderObject::willBeDestroyed();
     destroyLayer();
 }
 
 void RenderLayerModelObject::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 {
     if (RenderStyle* oldStyle = style()) {
-        if (parent() && diff.needsPaintInvalidationLayer()) {
+        if (parent()) {
             if (oldStyle->hasAutoClip() != newStyle.hasAutoClip()
                 || oldStyle->clip() != newStyle.clip())
                 layer()->clipper().clearClipRectsIncludingDescendants();
         }
     }
 
     RenderObject::styleWillChange(diff, newStyle);
 }
 
 void RenderLayerModelObject::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
@@ skipping 22 matching lines @@
     if (layer()) {
         // FIXME: Ideally we shouldn't need this setter but we can't easily infer an overflow-only layer
         // from the style.
         layer()->setLayerType(type);
         layer()->styleChanged(diff, oldStyle);
     }
 }
 
 } // namespace blink