Use reference for FillLayer if possible

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 994 matching lines @@
     RoundedRect roundedRect(pixelSnappedIntRect(innerRect));
 
     if (hasBorderRadius()) {
         RoundedRect::Radii radii = getRoundedBorderFor(borderRect).radii();
         radii.shrink(topWidth, bottomWidth, leftWidth, rightWidth);
         roundedRect.includeLogicalEdges(radii, isHorizontalWritingMode(), includeLogicalLeftEdge, includeLogicalRightEdge);
     }
     return roundedRect;
 }
 
-static bool allLayersAreFixed(const FillLayer* layer)
+static bool allLayersAreFixed(const FillLayer& layer)
 {
-    bool allFixed = true;
+    for (const FillLayer* currLayer = &layer; currLayer; currLayer = currLayer->next()) {
+        if (!currLayer->image() || currLayer->attachment() != FixedBackgroundAttachment)
+            return false;
+    }
 
-    for (const FillLayer* currLayer = layer; currLayer; currLayer = currLayer->next())
-        allFixed &= (currLayer->image() && currLayer->attachment() == FixedBackgroundAttachment);
-
-    return layer && allFixed;
+    return true;
 }
 
 bool RenderStyle::hasEntirelyFixedBackground() const
 {
     return allLayersAreFixed(backgroundLayers());
 }
 
 const CounterDirectiveMap* RenderStyle::counterDirectives() const
 {
     return rareNonInheritedData->m_counterDirectives.get();
@@ skipping 654 matching lines @@
     // right
     radiiSum = radii.topRight().height() + radii.bottomRight().height();
     if (radiiSum > rect.height())
         factor = std::min(rect.height() / radiiSum, factor);
 
     ASSERT(factor <= 1);
     return factor;
 }
 
 } // namespace WebCore