Calculate correct clip foregroundBound and backgroundBound

Source/core/paint/DeprecatedPaintLayer.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 1427 matching lines @@
         // TODO(chadarmstrong): If possible, this code should use the cache (one way would be by computing the root layer relative to |clipRectsCacheSlot|).
         ClipRectsContext clipRectsContext(ancestorLayer, UncachedClipRects, inOverlayScrollbarSizeRelevancy);
         if (respectOverflowClip == IgnoreOverflowClip)
             clipRectsContext.setIgnoreOverflowClip();
         ancestorClipRect = enclosingPaginationLayer()->clipper().backgroundClipRect(clipRectsContext);
         if (rootLayerIsInsidePaginationLayer)
             ancestorClipRect.moveBy(-rootLayer->visualOffsetFromAncestor(ancestorLayer));
         ancestorClipRect.intersect(dirtyRect);
     }
 
-    const LayoutSize subPixelAccumulationIfNeeded = compositingState() == PaintsIntoOwnBacking ? LayoutSize() : subPixelAccumulation;
+    const LayoutSize subPixelAccumulationIfNeeded = offsetFromRoot ? subPixelAccumulation : LayoutSize();
     for (size_t i = 0; i < fragments.size(); ++i) {
         DeprecatedPaintLayerFragment& fragment = fragments.at(i);
 
         // Set our four rects with all clipping applied that was internal to the flow thread.
         fragment.setRects(layerBoundsInFlowThread, backgroundRectInFlowThread, foregroundRectInFlowThread, outlineRectInFlowThread);
 
         // Shift to the root-relative physical position used when painting the flow thread in this fragment.
         fragment.moveBy(fragment.paginationOffset + offsetOfPaginationLayerFromRoot + subPixelAccumulationIfNeeded);
 
         // Intersect the fragment with our ancestor's background clip so that e.g., columns in an overflow:hidden block are
@@ skipping 1212 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif