Switch DPLStackingNode to use LayoutBoxModelObject

Source/core/paint/DeprecatedPaintLayerStackingNode.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 43 matching lines @@
 namespace blink {
 
 class DeprecatedPaintLayer;
 class DeprecatedPaintLayerCompositor;
 class ComputedStyle;
 class LayoutBoxModelObject;
 
 class CORE_EXPORT DeprecatedPaintLayerStackingNode {
     WTF_MAKE_NONCOPYABLE(DeprecatedPaintLayerStackingNode);
 public:
-    explicit DeprecatedPaintLayerStackingNode(DeprecatedPaintLayer*);
+    explicit DeprecatedPaintLayerStackingNode(LayoutBoxModelObject&);
     ~DeprecatedPaintLayerStackingNode();
 
-    int zIndex() const { return layoutObject()->style()->zIndex(); }
+    int zIndex() const { return layoutObject().style()->zIndex(); }
 
-    bool isStackingContext() const { return layoutObject()->style()->isStackingContext(); }
+    bool isStackingContext() const { return layoutObject().style()->isStackingContext(); }
 
     // Update our normal and z-index lists.
     void updateLayerListsIfNeeded();
 
     bool zOrderListsDirty() const { return m_zOrderListsDirty; }
     void dirtyZOrderLists();
     void updateZOrderLists();
     void clearZOrderLists();
     void dirtyStackingContextZOrderLists();
 
     bool hasPositiveZOrderList() const { return posZOrderList() && posZOrderList()->size(); }
     bool hasNegativeZOrderList() const { return negZOrderList() && negZOrderList()->size(); }
 
     // FIXME: should check for dirtiness here?
     bool isNormalFlowOnly() const { return !isTreatedAsStackingContextForPainting(); }
     bool isTreatedAsStackingContextForPainting() const { return m_isTreatedAsStackingContextForPainting; }
     void updateIsTreatedAsStackingContextForPainting();
     bool normalFlowListDirty() const { return m_normalFlowListDirty; }
     void dirtyNormalFlowList();
 
     void updateStackingNodesAfterStyleChange(const ComputedStyle* oldStyle);
 
     DeprecatedPaintLayerStackingNode* ancestorStackingContextNode() const;
 
-    DeprecatedPaintLayer* layer() const { return m_layer; }
+    // FIXME: A lot of code depends on this function but shouldn't. We should
+    // build our code on top of LayoutBoxModelObject, not DeprecatedPaintLayer.
+    DeprecatedPaintLayer* layer() const;

[dsinclair, 2015/06/24 19:40:50]

Should we consider adding an ASSERT in here and a disabler so we don't add more
callers or are there just too many to do that at the moment?

crbug to fix?

[Julien - ping for review, 2015/06/24 21:40:00]

We could make it private and whitelist the classes / functions using it (seems
cleaner than an ASSERT triggering IMHO).
I am not sure about where the whole effort would go, right now I am just
exploring the dependencies. I filed a bug (crbug.com/504125) as it's a good
direction.

 
 #if ENABLE(ASSERT)
     bool layerListMutationAllowed() const { return m_layerListMutationAllowed; }
     void setLayerListMutationAllowed(bool flag) { m_layerListMutationAllowed = flag; }
 #endif
 
 private:
     friend class DeprecatedPaintLayerStackingNodeIterator;
     friend class DeprecatedPaintLayerStackingNodeReverseIterator;
     friend class LayoutTreeAsText;
@@ skipping 12 matching lines @@
     }
 
     Vector<DeprecatedPaintLayerStackingNode*>* negZOrderList() const
     {
         ASSERT(!m_zOrderListsDirty);
         ASSERT(isStackingContext() || !m_negZOrderList);
         return m_negZOrderList.get();
     }
 
     void rebuildZOrderLists();
-    void collectLayers(OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>>& posZOrderList, OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>>& negZOrderList);
 
 #if ENABLE(ASSERT)
     bool isInStackingParentZOrderLists() const;
     bool isInStackingParentNormalFlowList() const;
     void updateStackingParentForZOrderLists(DeprecatedPaintLayerStackingNode* stackingParent);
     void updateStackingParentForNormalFlowList(DeprecatedPaintLayerStackingNode* stackingParent);
     void setStackingParent(DeprecatedPaintLayerStackingNode* stackingParent) { m_stackingParent = stackingParent; }
 #endif
 
-    bool shouldBeTreatedAsStackingContextForPainting() const { return layoutObject()->style()->isTreatedAsStackingContextForPainting(); }
+    bool shouldBeTreatedAsStackingContextForPainting() const { return layoutObject().style()->isTreatedAsStackingContextForPainting(); }
 
     void updateNormalFlowList();
 
     bool isDirtyStackingContext() const { return m_zOrderListsDirty && isStackingContext(); }
 
     DeprecatedPaintLayerCompositor* compositor() const;
     // We can't return a LayoutBox as LayoutInline can be a stacking context.
-    LayoutBoxModelObject* layoutObject() const;
+    LayoutBoxModelObject& layoutObject() const { return m_layoutObject; }
 
-    DeprecatedPaintLayer* m_layer;
+    LayoutBoxModelObject& m_layoutObject;
 
     // m_posZOrderList holds a sorted list of all the descendant nodes within
     // that have z-indices of 0 or greater (auto will count as 0).
     // m_negZOrderList holds descendants within our stacking context with
     // negative z-indices.
     OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_posZOrderList;
     OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_negZOrderList;
 
     // This list contains child nodes that cannot create stacking contexts.
     OwnPtr<Vector<DeprecatedPaintLayerStackingNode*>> m_normalFlowList;
@@ skipping 51 matching lines @@
 
 private:
     DeprecatedPaintLayerStackingNode* m_stackingNode;
     bool m_previousMutationAllowedState;
 };
 #endif
 
 } // namespace blink
 
 #endif // DeprecatedPaintLayerStackingNode_h