Factor painting code out of RenderBox into a new class called BoxPainter.

Source/core/rendering/RenderTableCell.cpp

Index: Source/core/rendering/RenderTableCell.cpp
diff --git a/Source/core/rendering/RenderTableCell.cpp b/Source/core/rendering/RenderTableCell.cpp
index a9b9d21fb05d8af6dc6bc44cff961e27934bc78d..a414d04accda2545ff3a8ad2bb1f379b8be576a4 100644
--- a/Source/core/rendering/RenderTableCell.cpp
+++ b/Source/core/rendering/RenderTableCell.cpp
@@ -43,7 +43,7 @@ using namespace HTMLNames;
 
 struct SameSizeAsRenderTableCell : public RenderBlockFlow {
     unsigned bitfields;
-    int paddings[2];
+    int paddings[4];
 };
 
 COMPILE_ASSERT(sizeof(RenderTableCell) == sizeof(SameSizeAsRenderTableCell), RenderTableCell_should_stay_small);
@@ -55,6 +55,7 @@ RenderTableCell::RenderTableCell(Element* element)
     , m_cellWidthChanged(false)
     , m_intrinsicPaddingBefore(0)
     , m_intrinsicPaddingAfter(0)
+    , m_boxPainter(BoxPainter(*this))
 {
     // We only update the flags when notified of DOM changes in colSpanOrRowSpanChanged()
     // so we need to set their initial values here in case something asks for colSpan()/rowSpan() before then.
@@ -1184,7 +1185,7 @@ void RenderTableCell::paintBackgroundsBehindCell(PaintInfo& paintInfo, const Lay
                 width() - borderLeft() - borderRight(), height() - borderTop() - borderBottom());
             paintInfo.context->clip(clipRect);
         }
-        paintFillLayers(paintInfo, c, bgLayer, LayoutRect(adjustedPaintOffset, pixelSnappedSize()), BackgroundBleedNone, CompositeSourceOver, backgroundObject);
+        m_boxPainter.paintFillLayers(paintInfo, c, bgLayer, LayoutRect(adjustedPaintOffset, pixelSnappedSize()), BackgroundBleedNone, CompositeSourceOver, backgroundObject);
     }
 }
 
@@ -1220,7 +1221,7 @@ void RenderTableCell::paintMask(PaintInfo& paintInfo, const LayoutPoint& paintOf
     if (!tableElt->collapseBorders() && style()->emptyCells() == HIDE && !firstChild())
         return;
 
-    paintMaskImages(paintInfo, LayoutRect(paintOffset, pixelSnappedSize()));
+    m_boxPainter.paintMaskImages(paintInfo, LayoutRect(paintOffset, pixelSnappedSize()));
 }
 
 bool RenderTableCell::boxShadowShouldBeAppliedToBackground(BackgroundBleedAvoidance, InlineFlowBox*) const