Calculate correct clip foregroundBound and backgroundBound

Source/core/paint/DeprecatedPaintLayer.cpp

Index: Source/core/paint/DeprecatedPaintLayer.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayer.cpp b/Source/core/paint/DeprecatedPaintLayer.cpp
index 8f81438d191b53a8bd1b75dbbeec10a6ec70eaf8..6efb76d384a4df5ca8420ab7a76c556a635db1b2 100644
--- a/Source/core/paint/DeprecatedPaintLayer.cpp
+++ b/Source/core/paint/DeprecatedPaintLayer.cpp
@@ -1383,7 +1383,8 @@ void DeprecatedPaintLayer::collectFragments(DeprecatedPaintLayerFragments& fragm
 {
     if (!enclosingPaginationLayer()) {
         // For unpaginated layers, there is only one fragment.
-        appendSingleFragmentIgnoringPagination(fragments, rootLayer, dirtyRect, clipRectsCacheSlot, inOverlayScrollbarSizeRelevancy, respectOverflowClip, offsetFromRoot, subPixelAccumulation);
+        const LayoutSize subPixelAccumulationIfNeeded = compositingState() == PaintsIntoOwnBacking ? LayoutSize() : subPixelAccumulation;
+        appendSingleFragmentIgnoringPagination(fragments, rootLayer, dirtyRect, clipRectsCacheSlot, inOverlayScrollbarSizeRelevancy, respectOverflowClip, offsetFromRoot, subPixelAccumulationIfNeeded);
         return;
     }