Use reference for paintInvalidationContainer param of invalidatePaintIfNeeded

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index 0acf4962c6c281f4ef9f01bebe56e798d2a47bff..bb132325c18078e308e23204f600a3a5be2a65c5 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -861,7 +861,7 @@ public:
     // Invalidate the paint of a specific subrectangle within a given object. The rect |r| is in the object's coordinate space.
     void invalidatePaintRectangle(const LayoutRect&) const;
 
-    bool invalidatePaintIfNeeded(const RenderLayerModelObject* paintInvalidationContainer,
+    bool invalidatePaintIfNeeded(const RenderLayerModelObject& paintInvalidationContainer,
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer);
 
     // Walk the tree after layout issuing paint invalidations for renderers that have changed or moved, updating bounds that have changed, and clearing paint invalidation state.
@@ -1114,11 +1114,11 @@ protected:
     // of this renderer within the current layer that should be used for each result.
     virtual void computeSelfHitTestRects(Vector<LayoutRect>&, const LayoutPoint& layerOffset) const { };
 
-    virtual InvalidationReason getPaintInvalidationReason(const RenderLayerModelObject* paintInvalidationContainer,
+    virtual InvalidationReason getPaintInvalidationReason(const RenderLayerModelObject& paintInvalidationContainer,
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer,
         const LayoutRect& newBounds, const LayoutPoint& newPositionFromPaintInvalidationContainer);
-    void incrementallyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds);
-    void fullyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, InvalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds);
+    void incrementallyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds);
+    void fullyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, InvalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds);
 
 private:
     const RenderLayerModelObject* enclosingCompositedContainer() const;