Don't invalidate paint on background image change if it's obscured

third_party/WebKit/Source/core/layout/LayoutBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 1017 matching lines @@
 
     void updateShapeOutsideInfoAfterStyleChange(const ComputedStyle&, const ComputedStyle* oldStyle);
     void updateGridPositionAfterStyleChange(const ComputedStyle*);
     void updateScrollSnapMappingAfterStyleChange(const ComputedStyle*, const ComputedStyle* oldStyle);
     void clearScrollSnapMapping();
     void addScrollSnapMapping();
 
     bool autoWidthShouldFitContent() const;
     LayoutUnit shrinkToFitLogicalWidth(LayoutUnit availableLogicalWidth, LayoutUnit bordersPlusPadding) const;
 
-    // Returns true if we queued up a paint invalidation.
-    bool invalidatePaintOfLayerRectsForImage(WrappedImagePtr, const FillLayer&, bool drawingBackground);
-
     bool stretchesToViewportInQuirksMode() const;
     bool skipContainingBlockForPercentHeightCalculation(const LayoutBox* containingBlock) const;
 
     virtual void computePositionedLogicalHeight(LogicalExtentComputedValues&) const;
     void computePositionedLogicalWidthUsing(SizeType, Length logicalWidth, const LayoutBoxModelObject* containerBlock, TextDirection containerDirection,
         LayoutUnit containerLogicalWidth, LayoutUnit bordersPlusPadding,
         const Length& logicalLeft, const Length& logicalRight, const Length& marginLogicalLeft,
         const Length& marginLogicalRight, LogicalExtentComputedValues&) const;
     void computePositionedLogicalHeightUsing(SizeType, Length logicalHeightLength, const LayoutBoxModelObject* containerBlock,
         LayoutUnit containerLogicalHeight, LayoutUnit bordersPlusPadding, LayoutUnit logicalHeight,
@@ skipping 40 matching lines @@
 
     void frameRectChanged()
     {
         // The frame rect may change because of layout of other objects.
         // Should check this object for paint invalidation.
         if (!needsLayout())
             setMayNeedPaintInvalidation();
     }
 
     // Returns true if the box intersects the viewport visible to the user.
-    bool intersectsVisibleViewport();
+    bool intersectsVisibleViewport() const;
 
     virtual bool isInSelfHitTestingPhase(HitTestAction hitTestAction) const { return hitTestAction == HitTestForeground; }
 
     void updateBackgroundAttachmentFixedStatusAfterStyleChange();
 
     // The CSS border box rect for this box.
     //
     // The rectangle is in this box's physical coordinates but with a
     // flipped block-flow direction (see the COORDINATE SYSTEMS section
     // in LayoutBoxModelObject). The location is the distance from this
@@ skipping 124 matching lines @@
         || breakValue == BreakLeft
         || breakValue == BreakPage
         || breakValue == BreakRecto
         || breakValue == BreakRight
         || breakValue == BreakVerso;
 }
 
 } // namespace blink
 
 #endif // LayoutBox_h