Use reference for paintInvalidationContainer param of invalidatePaintIfNeeded

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index f7ec67306de5cbf0cca3e93f9b28bf9d25ea7942..771e0ad4203c7647046241075c2810411ae9ddcd 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1619,7 +1619,7 @@ static PassRefPtr<TraceEvent::ConvertableToTraceFormat> jsonObjectForOldAndNewRe
     return value.finish();
 }
 
-bool RenderObject::invalidatePaintIfNeeded(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutPoint& oldLocation)
+bool RenderObject::invalidatePaintIfNeeded(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutPoint& oldLocation)
 {
     RenderView* v = view();
     if (v->document().printing())
@@ -1628,7 +1628,7 @@ bool RenderObject::invalidatePaintIfNeeded(const RenderLayerModelObject* paintIn
     const LayoutRect& newBounds = previousPaintInvalidationRect();
     const LayoutPoint& newLocation = previousPositionFromPaintInvalidationContainer();
 
-    ASSERT(newBounds == boundsRectForPaintInvalidation(paintInvalidationContainer));
+    ASSERT(newBounds == boundsRectForPaintInvalidation(&paintInvalidationContainer));
 
     // FIXME: This should use a ConvertableToTraceFormat when they are available in Blink.
     TRACE_EVENT2(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "RenderObject::invalidatePaintIfNeeded()",
@@ -1649,7 +1649,7 @@ bool RenderObject::invalidatePaintIfNeeded(const RenderLayerModelObject* paintIn
     return true;
 }
 
-InvalidationReason RenderObject::getPaintInvalidationReason(const RenderLayerModelObject* paintInvalidationContainer,
+InvalidationReason RenderObject::getPaintInvalidationReason(const RenderLayerModelObject& paintInvalidationContainer,
     const LayoutRect& oldBounds, const LayoutPoint& oldLocation, const LayoutRect& newBounds, const LayoutPoint& newLocation)
 {
     if (shouldDoFullPaintInvalidationAfterLayout())
@@ -1690,31 +1690,29 @@ InvalidationReason RenderObject::getPaintInvalidationReason(const RenderLayerMod
     return InvalidationIncremental;
 }
 
-void RenderObject::incrementallyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds)
+void RenderObject::incrementallyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds)
 {
-    ASSERT(paintInvalidationContainer);
-
     ASSERT(oldBounds.location() == newBounds.location());
 
     LayoutUnit deltaRight = newBounds.maxX() - oldBounds.maxX();
     if (deltaRight > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), InvalidationIncremental);
+        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), InvalidationIncremental);
     else if (deltaRight < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), InvalidationIncremental);
+        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), InvalidationIncremental);
 
     LayoutUnit deltaBottom = newBounds.maxY() - oldBounds.maxY();
     if (deltaBottom > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), InvalidationIncremental);
+        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), InvalidationIncremental);
     else if (deltaBottom < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), InvalidationIncremental);
+        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), InvalidationIncremental);
 }
 
-void RenderObject::fullyInvalidatePaint(const RenderLayerModelObject* paintInvalidationContainer, InvalidationReason invalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds)
+void RenderObject::fullyInvalidatePaint(const RenderLayerModelObject& paintInvalidationContainer, InvalidationReason invalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds)
 {
     // Otherwise do full paint invalidation.
-    invalidatePaintUsingContainer(paintInvalidationContainer, oldBounds, invalidationReason);
+    invalidatePaintUsingContainer(&paintInvalidationContainer, oldBounds, invalidationReason);
     if (newBounds != oldBounds)
-        invalidatePaintUsingContainer(paintInvalidationContainer, newBounds, invalidationReason);
+        invalidatePaintUsingContainer(&paintInvalidationContainer, newBounds, invalidationReason);
 }
 
 void RenderObject::invalidatePaintForOverflow()