Move LayoutBoxModelObject's PaintLayer member to rare paint data

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 217 matching lines @@
       }
     }
     return kBackgroundPaintInGraphicsLayer;
   }
   return paint_location;
 }
 
 LayoutBoxModelObject::~LayoutBoxModelObject() {
   // Our layer should have been destroyed and cleared by now
   DCHECK(!HasLayer());
-  DCHECK(!layer_);
+  DCHECK(!Layer());
 }
 
 void LayoutBoxModelObject::WillBeDestroyed() {
   ImageQualityController::Remove(*this);
 
   // A continuation of this LayoutObject should be destroyed at subclasses.
   DCHECK(!Continuation());
 
   if (IsPositioned()) {
     // Don't use this->view() because the document's layoutView has been set to
     // 0 during destruction.
     if (LocalFrame* frame = this->GetFrame()) {
       if (FrameView* frame_view = frame->View()) {
         if (Style()->HasViewportConstrainedPosition())
           frame_view->RemoveViewportConstrainedObject(*this);
       }
     }
   }
 
   LayoutObject::WillBeDestroyed();
 
-  DestroyLayer();
+  if (HasLayer())
+    DestroyLayer();
 }
 
 void LayoutBoxModelObject::StyleWillChange(StyleDifference diff,
                                            const ComputedStyle& new_style) {
   // This object's layer may begin or cease to be a stacking context, in which
   // case the paint invalidation container of this object and descendants may
   // change. Thus we need to invalidate paint eagerly for all such children.
   // PaintLayerCompositor::paintInvalidationOnCompositingChange() doesn't work
   // for the case because we can only see the new paintInvalidationContainer
   // during compositing update.
@@ skipping 50 matching lines @@
       ((old_style->OriginalDisplay() == EDisplay::kBlock) ||
        (old_style->OriginalDisplay() == EDisplay::kInlineBlock)))
     Parent()->SetNeedsLayout(LayoutInvalidationReason::kChildChanged,
                              kMarkContainerChain);
 
   PaintLayerType type = LayerTypeRequired();
   if (type != kNoPaintLayer) {
     if (!Layer() && LayerCreationAllowedForSubtree()) {
       if (was_floating_before_style_changed && IsFloating())
         SetChildNeedsLayout();
       CreateLayer();

[chrishtr, 2017/04/11 21:52:34]

Move 333 inside and call this CreateLayerAfterStyleChange?

[pdr., 2017/04/11 22:36:01]

Done

+      Layer()->InsertOnlyThisLayerAfterStyleChange();
       if (Parent() && !NeedsLayout()) {
         // FIXME: We should call a specialized version of this function.
         Layer()->UpdateLayerPositionsAfterLayout();
       }
     }
   } else if (Layer() && Layer()->Parent()) {
     PaintLayer* parent_layer = Layer()->Parent();
     // Either a transform wasn't specified or the object doesn't support
     // transforms, so just null out the bit.
     SetHasTransformRelatedProperty(false);
     SetHasReflection(false);
     Layer()->UpdateFilters(old_style, StyleRef());
     Layer()->UpdateClipPath(old_style, StyleRef());
-    // Calls destroyLayer() which clears m_layer.
+    // Calls DestroyLayer() which clears the layer.
     Layer()->RemoveOnlyThisLayerAfterStyleChange();
     if (was_floating_before_style_changed && IsFloating())
       SetChildNeedsLayout();
     if (had_transform_related_property) {
       SetNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(
           LayoutInvalidationReason::kStyleChange);
     }
     if (!NeedsLayout()) {
       // FIXME: We should call a specialized version of this function.
       parent_layer->UpdateLayerPositionsAfterLayout();
@@ skipping 140 matching lines @@
   // as if we have saved constraints for this layer they were saved in the
   // previous frame.
   DisableCompositingQueryAsserts disabler;
   if (const PaintLayer* ancestor_overflow_layer =
           enclosing->AncestorOverflowLayer())
     ancestor_overflow_layer->GetScrollableArea()
         ->InvalidateAllStickyConstraints();
 }
 
 void LayoutBoxModelObject::CreateLayer() {
-  DCHECK(!layer_);
-  layer_ = WTF::MakeUnique<PaintLayer>(*this);
+  DCHECK(!HasLayer() && !Layer());
+  EnsureRarePaintData().SetLayer(WTF::MakeUnique<PaintLayer>(*this));
   SetHasLayer(true);
-  layer_->InsertOnlyThisLayerAfterStyleChange();
 }
 
 void LayoutBoxModelObject::DestroyLayer() {
+  DCHECK(HasLayer() && Layer());
   SetHasLayer(false);
-  layer_ = nullptr;
+  GetRarePaintData()->SetLayer(nullptr);
 }
 
 bool LayoutBoxModelObject::HasSelfPaintingLayer() const {
-  return layer_ && layer_->IsSelfPaintingLayer();
+  return Layer() && Layer()->IsSelfPaintingLayer();
 }
 
 PaintLayerScrollableArea* LayoutBoxModelObject::GetScrollableArea() const {
-  return layer_ ? layer_->GetScrollableArea() : 0;
+  return Layer() ? Layer()->GetScrollableArea() : nullptr;
 }
 
 void LayoutBoxModelObject::AddLayerHitTestRects(
     LayerHitTestRects& rects,
     const PaintLayer* current_layer,
     const LayoutPoint& layer_offset,
     const LayoutRect& container_rect) const {
   if (HasLayer()) {
     if (IsLayoutView()) {
       // LayoutView is handled with a special fast-path, but it needs to know
@@ skipping 946 matching lines @@
   if (root_element_style->HasBackground())
     return false;
 
   if (GetNode() != GetDocument().FirstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink