Fix paint invalidation rect tracking within composited scrolling layers.

Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 979 matching lines @@
 
     virtual void addOutlineRects(Vector<LayoutRect>&, const LayoutPoint& additionalOffset) const { }
 
     // Compute a list of hit-test rectangles per layer rooted at this layoutObject.
     virtual void computeLayerHitTestRects(LayerHitTestRects&) const;
 
     RespectImageOrientationEnum shouldRespectImageOrientation() const;
 
     bool isRelayoutBoundaryForInspector() const;
 
-    // The previous paint invalidation rect in the object's previous paint backing.
-    const LayoutRect& previousPaintInvalidationRect() const { return m_previousPaintInvalidationRect; }
+    // The previous paint invalidation rect, in the the space of the paint invalidation container (*not* the graphics layer that paints
+    // this object).
+    LayoutRect previousPaintInvalidationRectIncludingCompositedScrolling(const LayoutBoxModelObject& paintInvalidationContainer) const;
     void setPreviousPaintInvalidationRect(const LayoutRect& rect) { m_previousPaintInvalidationRect = rect; }
 
+    // Only adjusts if the paint invalidation container is not a composited scroller.
+    void adjustPreviousPaintInvalidationForScrollIfNeeded(const DoubleSize& scrollDelta);
+
     // The previous position of the top-left corner of the object in its previous paint backing.
     const LayoutPoint& previousPositionFromPaintInvalidationBacking() const { return m_previousPositionFromPaintInvalidationBacking; }
     void setPreviousPositionFromPaintInvalidationBacking(const LayoutPoint& positionFromPaintInvalidationBacking) { m_previousPositionFromPaintInvalidationBacking = positionFromPaintInvalidationBacking; }
 
     PaintInvalidationReason fullPaintInvalidationReason() const { return m_bitfields.fullPaintInvalidationReason(); }
     bool shouldDoFullPaintInvalidation() const { return m_bitfields.fullPaintInvalidationReason() != PaintInvalidationNone; }
     void setShouldDoFullPaintInvalidation(PaintInvalidationReason = PaintInvalidationFull);
     void clearShouldDoFullPaintInvalidation() { m_bitfields.setFullPaintInvalidationReason(PaintInvalidationNone); }
 
     bool shouldInvalidateOverflowForPaint() const { return m_bitfields.shouldInvalidateOverflowForPaint(); }
@@ skipping 169 matching lines @@
 
     // When this object is invalidated for paint, this method is called to invalidate any DisplayItemClients
     // owned by this object, including the object itself, LayoutText/LayoutInline line boxes, etc.,
     // not including children which will be invalidated normally during invalidateTreeIfNeeded() and
     // parts which are invalidated separately (e.g. scrollbars).
     virtual void invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) const;
 
     void setIsSlowRepaintObject(bool);
 
 private:
+    const LayoutRect& previousPaintInvalidationRect() const { return m_previousPaintInvalidationRect; }
+
+    // Adjusts a paint invalidation rect in the space of |m_previousPaintInvalidationRect| and |m_previousPositionFromPaintInvalidationBacking|
+    // to be in the space of the |paintInvalidationContainer|,
+    // if needed. They can be different only if |paintInvalidationContainer| is a composited scroller.
+    void adjustInvalidationRectForCompositedScrolling(LayoutRect&, const LayoutBoxModelObject& paintInvalidationContainer) const;
+
     void clearLayoutRootIfNeeded() const;
 
     bool isInert() const;
 
     void updateImage(StyleImage*, StyleImage*);
 
     void scheduleRelayout();
 
     void updateShapeImage(const ShapeValue*, const ShapeValue*);
     void updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers);
@@ skipping 216 matching lines @@
     void setIsDragging(bool b) { m_bitfields.setIsDragging(b); }
     void setEverHadLayout(bool b) { m_bitfields.setEverHadLayout(b); }
     void setShouldInvalidateOverflowForPaint(bool b) { m_bitfields.setShouldInvalidateOverflowForPaint(b); }
     void setSelfNeedsOverflowRecalcAfterStyleChange(bool b) { m_bitfields.setSelfNeedsOverflowRecalcAfterStyleChange(b); }
     void setChildNeedsOverflowRecalcAfterStyleChange(bool b) { m_bitfields.setChildNeedsOverflowRecalcAfterStyleChange(b); }
 
 private:
     // Store state between styleWillChange and styleDidChange
     static bool s_affectsParentBlock;
 
-    // This stores the paint invalidation rect from the previous frame.
+    // This stores the paint invalidation rect from the previous frame. This rect does *not* account for composited scrolling. See
+    // adjustInvalidationRectForCompositedScrolling().
     LayoutRect m_previousPaintInvalidationRect;
 
     // This stores the position in the paint invalidation backing's coordinate.
     // It is used to detect layoutObject shifts that forces a full invalidation.
+    // This point does *not* account for composited scrolling. See adjustInvalidationRectForCompositedScrolling().
     LayoutPoint m_previousPositionFromPaintInvalidationBacking;
 };
 
 // FIXME: remove this once the layout object lifecycle ASSERTS are no longer hit.
 class DeprecatedDisableModifyLayoutTreeStructureAsserts {
     WTF_MAKE_NONCOPYABLE(DeprecatedDisableModifyLayoutTreeStructureAsserts);
 public:
     DeprecatedDisableModifyLayoutTreeStructureAsserts();
 
     static bool canModifyLayoutTreeStateInAnyState();
@@ skipping 213 matching lines @@
 void showTree(const blink::LayoutObject*);
 void showLineTree(const blink::LayoutObject*);
 void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 void showLayoutTree(const blink::LayoutObject* object1, const blink::LayoutObject* object2);
 
 #endif
 
 #endif // LayoutObject_h