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

Source/core/rendering/RenderFieldset.cpp

Index: Source/core/rendering/RenderFieldset.cpp
diff --git a/Source/core/rendering/RenderFieldset.cpp b/Source/core/rendering/RenderFieldset.cpp
index 928eb192be8a5adb3b1f07c6af901dfe20bf9d74..68d9ad2ca76c8d93b58493380e9c8ebae05d9110 100644
--- a/Source/core/rendering/RenderFieldset.cpp
+++ b/Source/core/rendering/RenderFieldset.cpp
@@ -27,6 +27,8 @@
 #include "core/CSSPropertyNames.h"
 #include "core/HTMLNames.h"
 #include "core/html/HTMLLegendElement.h"
+#include "core/paint/BoxDecorationData.h"
+#include "core/paint/BoxPainter.h"
 #include "core/rendering/PaintInfo.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 
@@ -159,11 +161,11 @@ void RenderFieldset::paintBoxDecorationBackground(PaintInfo& paintInfo, const La
         paintRect.setX(paintRect.x() + xOff);
     }
 
-    BoxDecorationData boxDecorationData(*style());
+    BoxDecorationData boxDecorationData(*style(), canRenderBorderImage(), backgroundHasOpaqueTopLayer(), paintInfo.context);
 
-    if (!boxShadowShouldBeAppliedToBackground(determineBackgroundBleedAvoidance(paintInfo.context, boxDecorationData)))
+    if (boxDecorationData.bleedAvoidance() == BackgroundBleedNone)
         paintBoxShadow(paintInfo, paintRect, style(), Normal);
-    paintFillLayers(paintInfo, boxDecorationData.backgroundColor, style()->backgroundLayers(), paintRect);
+    BoxPainter(*this).paintFillLayers(paintInfo, boxDecorationData.backgroundColor, style()->backgroundLayers(), paintRect);
     paintBoxShadow(paintInfo, paintRect, style(), Inset);
 
     if (!boxDecorationData.hasBorder)
@@ -212,7 +214,7 @@ void RenderFieldset::paintMask(PaintInfo& paintInfo, const LayoutPoint& paintOff
         paintRect.move(xOff, 0);
     }
 
-    paintMaskImages(paintInfo, paintRect);
+    BoxPainter(*this).paintMaskImages(paintInfo, paintRect);
 }
 
 } // namespace blink