WIP: Skeleton for paint offset caching

Source/core/paint/PartPainter.cpp

Index: Source/core/paint/PartPainter.cpp
diff --git a/Source/core/paint/PartPainter.cpp b/Source/core/paint/PartPainter.cpp
index 8eba600cf3bd8803d8cdc048a2f848ac0a0a21e4..e3f28fdd2a9a53ce947fa5c3d13c7a6f98175f2b 100644
--- a/Source/core/paint/PartPainter.cpp
+++ b/Source/core/paint/PartPainter.cpp
@@ -37,7 +37,7 @@ void PartPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffs
     visualOverflowRect.moveBy(adjustedPaintOffset);
 
     if ((paintInfo.phase == PaintPhaseOutline || paintInfo.phase == PaintPhaseSelfOutline) && m_layoutPart.style()->hasOutline())
-        ObjectPainter(m_layoutPart).paintOutline(paintInfo, borderRect, visualOverflowRect);
+        ObjectPainter(m_layoutPart).paintOutline(paintInfo, borderRect, visualOverflowRect, adjustedPaintOffset);
 
     if (paintInfo.phase != PaintPhaseForeground)
         return;
@@ -63,11 +63,11 @@ void PartPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffs
     }
 
     // Paint a partially transparent wash over selected widgets.
-    if (m_layoutPart.isSelected() && !paintInfo.isPrinting() && !LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*paintInfo.context, m_layoutPart, paintInfo.phase)) {
+    if (m_layoutPart.isSelected() && !paintInfo.isPrinting() && !LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(*paintInfo.context, m_layoutPart, paintInfo.phase, adjustedPaintOffset)) {
         LayoutRect rect = m_layoutPart.localSelectionRect();
         rect.moveBy(adjustedPaintOffset);
         IntRect selectionRect = pixelSnappedIntRect(rect);
-        LayoutObjectDrawingRecorder drawingRecorder(*paintInfo.context, m_layoutPart, paintInfo.phase, selectionRect);
+        LayoutObjectDrawingRecorder drawingRecorder(*paintInfo.context, m_layoutPart, paintInfo.phase, selectionRect, adjustedPaintOffset);
         paintInfo.context->fillRect(selectionRect, m_layoutPart.selectionBackgroundColor());
     }