LayoutObject::invalidatePaintIfNeededForSynchronizedPainting() and plumbing

third_party/WebKit/Source/core/paint/BlockPainter.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/BlockPainter.h"
 
 #include "core/editing/DragCaretController.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/Settings.h"
@@ skipping 133 matching lines @@
 void BlockPainter::paintObject(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     if (RuntimeEnabledFeatures::slimmingPaintOffsetCachingEnabled() && m_layoutBlock.childrenInline() && !paintInfo.context->displayItemList()->skippingCache()) {
         if (m_layoutBlock.paintOffsetChanged(paintOffset)) {
             LineBoxListPainter(m_layoutBlock.lineBoxes()).invalidateLineBoxPaintOffsets(paintInfo);
             paintInfo.context->displayItemList()->invalidatePaintOffset(m_layoutBlock);
         }
         // Set previousPaintOffset here in case that m_layoutBlock paints nothing and no
         // LayoutObjectDrawingRecorder updates its previousPaintOffset.
         // TODO(wangxianzhu): Integrate paint offset checking into new paint invalidation.
-        m_layoutBlock.setPreviousPaintOffset(paintOffset);
+        m_layoutBlock.mutableForPainting().setPreviousPaintOffset(paintOffset);
     }
 
     const PaintPhase paintPhase = paintInfo.phase;
 
     if ((paintPhase == PaintPhaseBlockBackground || paintPhase == PaintPhaseChildBlockBackground)
         && m_layoutBlock.style()->visibility() == VISIBLE
         && m_layoutBlock.hasBoxDecorationBackground())
         m_layoutBlock.paintBoxDecorationBackground(paintInfo, paintOffset);
 
     if (paintPhase == PaintPhaseMask && m_layoutBlock.style()->visibility() == VISIBLE) {
@@ skipping 94 matching lines @@
 
         // We don't paint our own background, but we do let the kids paint their backgrounds.
         PaintInfo paintInfoForChild(paintInfo);
         paintInfoForChild.phase = newPhase;
         paintInfoForChild.updatePaintingRootForChildren(&m_layoutBlock);
         m_layoutBlock.paintChildren(paintInfoForChild, paintOffset);
     }
 }
 
 } // namespace blink