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

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index 99c342b09fb7bc2f96d986827575ba24c5d1232d..4c619bb8fd567091e1704f2ccfa12705ce84eb76 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -1035,9 +1035,6 @@ private:
     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;
 
@@ -1098,7 +1095,7 @@ private:
     }
 
     // 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; }