Simplify paint rect calculations in LayoutReplaced::shouldPaint

Source/core/layout/LayoutReplaced.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 106 matching lines @@
         && paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseMask && paintInfo.phase != PaintPhaseClippingMask)
         return false;
 
     if (!paintInfo.shouldPaintWithinRoot(this))
         return false;
 
     // if we're invisible or haven't received a layout yet, then just bail.
     if (style()->visibility() != VISIBLE)
         return false;
 
-    LayoutPoint adjustedPaintOffset = paintOffset + location();
+    LayoutRect paintRect(visualOverflowRect());
+    paintRect.moveBy(paintOffset + location());
 
     // Early exit if the element touches the edges.
-    LayoutUnit top = adjustedPaintOffset.y() + visualOverflowRect().y();
-    LayoutUnit bottom = adjustedPaintOffset.y() + visualOverflowRect().maxY();
+    LayoutUnit top = paintRect.y();
+    LayoutUnit bottom = paintRect.maxY();
     if (isSelected() && inlineBoxWrapper()) {
         LayoutUnit selTop = paintOffset.y() + inlineBoxWrapper()->root().selectionTop();
         LayoutUnit selBottom = paintOffset.y() + selTop + inlineBoxWrapper()->root().selectionHeight();
         top = std::min(selTop, top);
         bottom = std::max(selBottom, bottom);
     }
 
-    if (adjustedPaintOffset.x() + visualOverflowRect().x() >= paintInfo.rect.maxX() || adjustedPaintOffset.x() + visualOverflowRect().maxX() <= paintInfo.rect.x())
+    if (paintRect.x() >= paintInfo.rect.maxX() || paintRect.maxX() <= paintInfo.rect.x())
         return false;
 
     if (top >= paintInfo.rect.maxY() || bottom <= paintInfo.rect.y())
         return false;
 
     return true;
 }
 
 bool LayoutReplaced::hasReplacedLogicalHeight() const
 {
@@ skipping 360 matching lines @@
         return LayoutRect();
 
     // The selectionRect can project outside of the overflowRect, so take their union
     // for paint invalidation to avoid selection painting glitches.
     LayoutRect r = isSelected() ? localSelectionRect() : visualOverflowRect();
     mapRectToPaintInvalidationBacking(paintInvalidationContainer, r, paintInvalidationState);
     return r;
 }
 
 }