Refactor to simplify how layerType is stored on PaintLayers.

third_party/WebKit/Source/core/paint/PaintLayer.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 191 matching lines @@
 // introduction of satellite objects: PaintLayer*. Those helper objects then
 // need to be moved to the appropriate LayoutObject class, probably to a rare
 // data field to avoid growing all the LayoutObjects.
 //
 // A good example of this is PaintLayerScrollableArea, which can only happen
 // be instanciated for LayoutBoxes. With the current design, it's hard to know
 // that by reading the code.
 class CORE_EXPORT PaintLayer : public DisplayItemClient {
     WTF_MAKE_NONCOPYABLE(PaintLayer);
 public:
-    PaintLayer(LayoutBoxModelObject*, PaintLayerType);
+    PaintLayer(LayoutBoxModelObject*);
     ~PaintLayer() override;
 
     // DisplayItemClient methods
     String debugName() const final;
     LayoutRect visualRect() const final;
 
     LayoutBoxModelObject* layoutObject() const { return m_layoutObject; }
     LayoutBox* layoutBox() const { return m_layoutObject && m_layoutObject->isBox() ? toLayoutBox(m_layoutObject) : 0; }
     PaintLayer* parent() const { return m_parent; }
     PaintLayer* previousSibling() const { return m_previous; }
     PaintLayer* nextSibling() const { return m_next; }
     PaintLayer* firstChild() const { return m_first; }
     PaintLayer* lastChild() const { return m_last; }
 
     // TODO(wangxianzhu): Find a better name for it. 'paintContainer' might be good but
     // we can't use it for now because it conflicts with PaintInfo::paintContainer.
     PaintLayer* compositingContainer() const;
 
     void addChild(PaintLayer* newChild, PaintLayer* beforeChild = 0);
     PaintLayer* removeChild(PaintLayer*);
 
     void removeOnlyThisLayerAfterStyleChange();
     void insertOnlyThisLayerAfterStyleChange();
 
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle);
 
     // FIXME: Many people call this function while it has out-of-date information.
     bool isSelfPaintingLayer() const { return m_isSelfPaintingLayer; }
 
-    void setLayerType(PaintLayerType layerType) { m_layerType = layerType; ASSERT(static_cast<PaintLayerType>(m_layerType) == layerType); }
-
     bool isTransparent() const { return layoutObject()->isTransparent() || layoutObject()->style()->hasBlendMode() || layoutObject()->hasMask(); }
 
     bool isReflection() const { return layoutObject()->isReplica(); }
     PaintLayerReflectionInfo* reflectionInfo() { return m_rareData ? m_rareData->reflectionInfo.get() : nullptr; }
     const PaintLayerReflectionInfo* reflectionInfo() const { return const_cast<PaintLayer*>(this)->reflectionInfo(); }
 
     const PaintLayer* root() const
     {
         const PaintLayer* curr = this;
         while (curr->parent())
@@ skipping 525 matching lines @@
         return *m_rareData;
     }
 
     void mergeNeedsPaintPhaseFlagsFrom(const PaintLayer& layer)
     {
         m_needsPaintPhaseDescendantOutlines |= layer.m_needsPaintPhaseDescendantOutlines;
         m_needsPaintPhaseFloat |= layer.m_needsPaintPhaseFloat;
         m_needsPaintPhaseDescendantBlockBackgrounds |= layer.m_needsPaintPhaseDescendantBlockBackgrounds;
     }
 
-    unsigned m_layerType : 2; // PaintLayerType
-
     // Self-painting layer is an optimization where we avoid the heavy Layer painting
     // machinery for a Layer allocated only to handle the overflow clip case.
     // FIXME(crbug.com/332791): Self-painting layer should be merged into the overflow-only concept.
     unsigned m_isSelfPaintingLayer : 1;
 
     // If have no self-painting descendants, we don't have to walk our children during painting. This can lead to
     // significant savings, especially if the tree has lots of non-self-painting layers grouped together (e.g. table cells).
     mutable unsigned m_hasSelfPaintingLayerDescendant : 1;
     mutable unsigned m_hasSelfPaintingLayerDescendantDirty : 1;
 
@@ skipping 91 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::PaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h