Don't use cached subsequence when clip changes

third_party/WebKit/Source/core/paint/PaintLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 598 matching lines @@
     static LayoutRect transparencyClipBox(const PaintLayer*, const PaintLayer* rootLayer, TransparencyClipBoxBehavior transparencyBehavior,
         TransparencyClipBoxMode transparencyMode, const LayoutSize& subPixelAccumulation, GlobalPaintFlags = GlobalPaintNormalPhase);
 
     bool needsRepaint() const { return m_needsRepaint; }
     void setNeedsRepaint();
     void clearNeedsRepaintRecursively();
 
     IntSize previousScrollOffsetAccumulationForPainting() const { return m_previousScrollOffsetAccumulationForPainting; }
     void setPreviousScrollOffsetAccumulationForPainting(const IntSize& s) { m_previousScrollOffsetAccumulationForPainting = s; }
 
+    ClipRects* previousPaintingClipRects() const { return m_previousPaintingClipRects.get(); }
+    void setPreviousPaintingClipRects(ClipRects* clipRects) { m_previousPaintingClipRects = clipRects; }
+
     // For subsequence display items.
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
 
 private:
     // Bounding box in the coordinates of this layer.
     LayoutRect logicalBoundingBox() const;
 
     bool hasOverflowControls() const;
 
     void dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();
@@ skipping 170 matching lines @@
 
     CompositedLayerMapping* m_groupedMapping;
 
     PaintLayerClipper m_clipper; // FIXME: Lazily allocate?
     OwnPtr<PaintLayerStackingNode> m_stackingNode;
     OwnPtr<PaintLayerReflectionInfo> m_reflectionInfo;
 
     LayoutSize m_subpixelAccumulation; // The accumulated subpixel offset of a composited layer's composited bounds compared to absolute coordinates.
 
     IntSize m_previousScrollOffsetAccumulationForPainting;
+    RefPtr<ClipRects> m_previousPaintingClipRects;
 };
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::PaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h