Implement a paint offset cache for slimming paint v2

Source/core/paint/PartPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/PartPainter.h"
 
 #include "core/layout/LayoutPart.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/DeprecatedPaintLayer.h"
@@ skipping 42 matching lines @@
                     -(m_layoutPart.paddingLeft() + m_layoutPart.borderLeft())),
                 true, true);
             clipper.emplace(m_layoutPart, paintInfo, borderRect, roundedInnerRect, ApplyToDisplayListIfEnabled);
         }
 
         if (m_layoutPart.widget())
             m_layoutPart.paintContents(paintInfo, paintOffset);
     }
 
     // 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());
     }
 
     if (m_layoutPart.canResize())
         ScrollableAreaPainter(*m_layoutPart.layer()->scrollableArea()).paintResizer(paintInfo.context, roundedIntPoint(adjustedPaintOffset), paintInfo.rect);
 }
 
 void PartPainter::paintContents(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     LayoutPoint adjustedPaintOffset = paintOffset + m_layoutPart.location();
@@ skipping 11 matching lines @@
     IntSize widgetPaintOffset = paintLocation - widgetLocation;
     // When painting widgets into compositing layers, tx and ty are relative to the enclosing compositing layer,
     // not the root. In this case, shift the CTM and adjust the paintRect to be root-relative to fix plugin drawing.
     TransformRecorder transform(*paintInfo.context, m_layoutPart,
         AffineTransform::translation(widgetPaintOffset.width(), widgetPaintOffset.height()));
     paintRect.move(-widgetPaintOffset);
     widget->paint(paintInfo.context, paintRect);
 }
 
 } // namespace blink