Change PaintLayer::m_layoutObject to a reference.

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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
@@ skipping 191 matching lines @@
 
   // A continuation of this LayoutObject should be destroyed at subclasses.
   ASSERT(!continuation());
 
   if (isPositioned()) {
     // Don't use this->view() because the document's layoutView has been set to
     // 0 during destruction.
     if (LocalFrame* frame = this->frame()) {
       if (FrameView* frameView = frame->view()) {
         if (style()->hasViewportConstrainedPosition())
-          frameView->removeViewportConstrainedObject(this);
+          frameView->removeViewportConstrainedObject(*this);
       }
     }
   }
 
   LayoutObject::willBeDestroyed();
 
   destroyLayer();
 }
 
 void LayoutBoxModelObject::styleWillChange(StyleDifference diff,
@@ skipping 175 matching lines @@
         // position constraints then.
         if (layer())
           layer()->setNeedsCompositingInputsUpdate();
 
         // TODO(pdr): When slimming paint v2 is enabled, we will need to
         // invalidate the scroll paint property subtree for this so main thread
         // scroll reasons are recomputed.
       } else {
         // This may get re-added to viewport constrained objects if the object
         // went from sticky to fixed.
-        frameView->removeViewportConstrainedObject(this);
+        frameView->removeViewportConstrainedObject(*this);
 
         // Remove sticky constraints for this layer.
         if (layer()) {
           DisableCompositingQueryAsserts disabler;
           if (const PaintLayer* ancestorOverflowLayer =
                   layer()->ancestorOverflowLayer()) {
             if (PaintLayerScrollableArea* scrollableArea =
                     ancestorOverflowLayer->getScrollableArea())
               scrollableArea->invalidateStickyConstraintsFor(layer());
           }
         }
 
         // TODO(pdr): When slimming paint v2 is enabled, we will need to
         // invalidate the scroll paint property subtree for this so main thread
         // scroll reasons are recomputed.
       }
     }
 
     if (newStyleIsViewportConstained != oldStyleIsViewportConstrained) {
       if (newStyleIsViewportConstained && layer())
-        frameView->addViewportConstrainedObject(this);
+        frameView->addViewportConstrainedObject(*this);
       else
-        frameView->removeViewportConstrainedObject(this);
+        frameView->removeViewportConstrainedObject(*this);
     }
   }
 }
 
 void LayoutBoxModelObject::invalidateStickyConstraints() {
   PaintLayer* enclosing = enclosingLayer();
 
   if (PaintLayerScrollableArea* scrollableArea =
           enclosing->getScrollableArea()) {
     scrollableArea->invalidateAllStickyConstraints();
     // If this object doesn't have a layer and its enclosing layer is a scroller
     // then we don't need to invalidate the sticky constraints on the ancestor
     // scroller because the enclosing scroller won't have changed size.
     if (!layer())
       return;
   }
 
   // This intentionally uses the stale ancestor overflow layer compositing input
   // as if we have saved constraints for this layer they were saved in the
   // previous frame.
   DisableCompositingQueryAsserts disabler;
   if (const PaintLayer* ancestorOverflowLayer =
           enclosing->ancestorOverflowLayer())
     ancestorOverflowLayer->getScrollableArea()
         ->invalidateAllStickyConstraints();
 }
 
 void LayoutBoxModelObject::createLayer() {
   ASSERT(!m_layer);
-  m_layer = WTF::makeUnique<PaintLayer>(this);
+  m_layer = WTF::makeUnique<PaintLayer>(*this);
   setHasLayer(true);
   m_layer->insertOnlyThisLayerAfterStyleChange();
 }
 
 void LayoutBoxModelObject::destroyLayer() {
   setHasLayer(false);
   m_layer = nullptr;
 }
 
 bool LayoutBoxModelObject::hasSelfPaintingLayer() const {
@@ skipping 332 matching lines @@
   MapCoordinatesFlags flags = 0;
   skippedContainersOffset =
       toFloatSize(locationContainer
                       ->localToAncestorQuadWithoutTransforms(
                           FloatQuad(), containingBlock, flags)
                       .boundingBox()
                       .location());
   LayoutBox* scrollAncestor =
       layer()->ancestorOverflowLayer()->isRootLayer()
           ? nullptr
-          : toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
+          : &toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
 
   LayoutUnit maxContainerWidth =
       containingBlock->isLayoutView()
           ? containingBlock->logicalWidth()
           : containingBlock->containingBlockLogicalWidthForContent();
   // Sticky positioned element ignore any override logical width on the
   // containing block, as they don't call containingBlockLogicalWidthForContent.
   // It's unclear whether this is totally fine.
   // Compute the container-relative area within which the sticky element is
   // allowed to move.
@@ skipping 138 matching lines @@
         StickyPositionScrollingConstraints::AnchorEdgeBottom);
   }
   scrollableArea->stickyConstraintsMap().set(layer(), constraints);
 }
 
 FloatRect LayoutBoxModelObject::computeStickyConstrainingRect() const {
   if (layer()->ancestorOverflowLayer()->isRootLayer())
     return view()->frameView()->visibleContentRect();
 
   LayoutBox* enclosingClippingBox =
-      toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
+      layer()->ancestorOverflowLayer()->layoutBox();
+  DCHECK(enclosingClippingBox);
   FloatRect constrainingRect;
   constrainingRect =
       FloatRect(enclosingClippingBox->overflowClipRect(LayoutPoint(DoublePoint(
           enclosingClippingBox->getScrollableArea()->scrollPosition()))));
   constrainingRect.move(
       -enclosingClippingBox->borderLeft() + enclosingClippingBox->paddingLeft(),
       -enclosingClippingBox->borderTop() + enclosingClippingBox->paddingTop());
   constrainingRect.contract(
       FloatSize(enclosingClippingBox->paddingLeft() +
                     enclosingClippingBox->paddingRight(),
@@ skipping 383 matching lines @@
   if (rootElementStyle->hasBackground())
     return false;
 
   if (node() != document().firstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink