Implement interfaces in PaintInfo and make it a class.

Source/core/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 4018 matching lines @@
     for (size_t i = 0; i < layerFragments.size(); ++i) {
         const LayerFragment& fragment = layerFragments.at(i);
         if (!fragment.shouldPaintContent || fragment.foregroundRect.isEmpty())
             continue;
 
         if (shouldClip)
             clipToRect(localPaintingInfo.rootLayer, context, localPaintingInfo.paintDirtyRect, fragment.foregroundRect);
 
         PaintInfo paintInfo(context, pixelSnappedIntRect(fragment.foregroundRect.rect()), phase, paintBehavior, paintingRootForRenderer, localPaintingInfo.region, 0, 0, localPaintingInfo.rootLayer->renderer());
         if (phase == PaintPhaseForeground)
-            paintInfo.overlapTestRequests = localPaintingInfo.overlapTestRequests;
+            paintInfo.setOverlapTestRequests(localPaintingInfo.overlapTestRequests);
         renderer()->paint(paintInfo, toPoint(fragment.layerBounds.location() - renderBoxLocation() + localPaintingInfo.subPixelAccumulation));
 
         if (shouldClip)
             restoreClip(context, localPaintingInfo.paintDirtyRect, fragment.foregroundRect);
     }
 }
 
 void RenderLayer::paintOutlineForFragments(const LayerFragments& layerFragments, GraphicsContext* context, const LayerPaintingInfo& localPaintingInfo,
     PaintBehavior paintBehavior, RenderObject* paintingRootForRenderer)
 {
@@ skipping 2316 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif