Use reference for paintInvalidationContainer param of invalidatePaintIfNeeded

Source/core/rendering/RenderBox.h

Index: Source/core/rendering/RenderBox.h
diff --git a/Source/core/rendering/RenderBox.h b/Source/core/rendering/RenderBox.h
index ec4682cbce8439c73d811e872f3c5adc10dbff1b..9eac296f2f483f37a52370a3889b34b96ce9bc3f 100644
--- a/Source/core/rendering/RenderBox.h
+++ b/Source/core/rendering/RenderBox.h
@@ -662,10 +662,10 @@ protected:
 
     void updateIntrinsicContentLogicalHeight(LayoutUnit intrinsicContentLogicalHeight) const { m_intrinsicContentLogicalHeight = intrinsicContentLogicalHeight; }
 
-    virtual InvalidationReason getPaintInvalidationReason(const RenderLayerModelObject* paintInvalidationContainer,
+    virtual InvalidationReason getPaintInvalidationReason(const RenderLayerModelObject& paintInvalidationContainer,
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer,
         const LayoutRect& newBounds, const LayoutPoint& newPositionFromPaintInvalidationContainer) OVERRIDE;
-    virtual void incrementallyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds) OVERRIDE;
+    virtual void incrementallyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds) OVERRIDE;
 
 private:
     void updateShapeOutsideInfoAfterStyleChange(const RenderStyle&, const RenderStyle* oldStyle);