Convert CompositingLayerMapping code to use reference

Source/core/rendering/compositing/CompositedLayerMapping.h

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 61 matching lines @@
 // CompositedLayerMapping keeps track of how RenderLayers of the render tree correspond to
 // GraphicsLayers of the composited layer tree. Each instance of CompositedLayerMapping
 // manages a small cluster of GraphicsLayers and the references to which RenderLayers
 // and paint phases contribute to each GraphicsLayer.
 //
 // Currently (Oct. 2013) there is one CompositedLayerMapping for each RenderLayer,
 // but this is likely to evolve soon.
 class CompositedLayerMapping FINAL : public GraphicsLayerClient {
     WTF_MAKE_NONCOPYABLE(CompositedLayerMapping); WTF_MAKE_FAST_ALLOCATED;
 public:
-    explicit CompositedLayerMapping(RenderLayer*);
+    explicit CompositedLayerMapping(RenderLayer&);
     virtual ~CompositedLayerMapping();
 
-    RenderLayer* owningLayer() const { return m_owningLayer; }
+    RenderLayer& owningLayer() const { return m_owningLayer; }
 
     enum UpdateAfterLayoutFlag {
         CompositingChildrenOnly = 1 << 0,
         NeedsFullRepaint = 1 << 1,
         IsUpdateRoot = 1 << 2
     };
     typedef unsigned UpdateAfterLayoutFlags;
     void updateAfterLayout(UpdateAfterLayoutFlags);
 
     // Returns true if layer configuration changed.
@@ skipping 105 matching lines @@
     virtual String debugName(const GraphicsLayer*) OVERRIDE;
 
     LayoutSize subpixelAccumulation() const { return m_subpixelAccumulation; }
 private:
     void createPrimaryGraphicsLayer();
     void destroyGraphicsLayers();
 
     PassOwnPtr<GraphicsLayer> createGraphicsLayer(CompositingReasons);
     bool toggleScrollbarLayerIfNeeded(OwnPtr<GraphicsLayer>&, bool needsLayer, CompositingReasons);
 
-    RenderLayerModelObject* renderer() const { return m_owningLayer->renderer(); }
-    RenderLayerCompositor* compositor() const { return m_owningLayer->compositor(); }
+    RenderLayerModelObject* renderer() const { return m_owningLayer.renderer(); }
+    RenderLayerCompositor* compositor() const { return m_owningLayer.compositor(); }
 
     void updateInternalHierarchy();
     bool updateClippingLayers(bool needsAncestorClip, bool needsDescendantClip);
     bool updateChildTransformLayer(bool needsChildTransformLayer);
     bool updateOverflowControlsLayers(bool needsHorizontalScrollbarLayer, bool needsVerticalScrollbarLayer, bool needsScrollCornerLayer);
     bool updateForegroundLayer(bool needsForegroundLayer);
     bool updateBackgroundLayer(bool needsBackgroundLayer);
     bool updateMaskLayer(bool needsMaskLayer);
     bool updateClippingMaskLayers(bool needsChildClippingMaskLayer);
-    bool requiresHorizontalScrollbarLayer() const { return m_owningLayer->scrollableArea() && m_owningLayer->scrollableArea()->horizontalScrollbar(); }
-    bool requiresVerticalScrollbarLayer() const { return m_owningLayer->scrollableArea() && m_owningLayer->scrollableArea()->verticalScrollbar(); }
-    bool requiresScrollCornerLayer() const { return m_owningLayer->scrollableArea() && !m_owningLayer->scrollableArea()->scrollCornerAndResizerRect().isEmpty(); }
+    bool requiresHorizontalScrollbarLayer() const { return m_owningLayer.scrollableArea() && m_owningLayer.scrollableArea()->horizontalScrollbar(); }
+    bool requiresVerticalScrollbarLayer() const { return m_owningLayer.scrollableArea() && m_owningLayer.scrollableArea()->verticalScrollbar(); }
+    bool requiresScrollCornerLayer() const { return m_owningLayer.scrollableArea() && !m_owningLayer.scrollableArea()->scrollCornerAndResizerRect().isEmpty(); }
     bool updateScrollingLayers(bool scrollingLayers);
     void updateScrollParent(RenderLayer*);
     void updateClipParent(RenderLayer*);
     bool updateSquashingLayers(bool needsSquashingLayers);
     void updateDrawsContent();
     void updateChildrenTransform();
     void registerScrollingLayers();
 
     void adjustBoundsForSubPixelAccumulation(const RenderLayer* compositedAncestor, IntRect& localCompositingBounds, IntRect& relativeCompositingBounds, IntPoint& delta);
 
@@ skipping 33 matching lines @@
     void updateCompositingReasons();
 
     bool hasVisibleNonCompositingDescendantLayers() const;
 
     bool shouldClipCompositedBounds() const;
 
     void paintsIntoCompositedAncestorChanged();
 
     void doPaintTask(GraphicsLayerPaintInfo&, GraphicsContext*, const IntRect& clip);
 
-    RenderLayer* m_owningLayer;
+    RenderLayer& m_owningLayer;
 
     // The hierarchy of layers that is maintained by the CompositedLayerMapping looks like this:
     //
     //  + m_ancestorClippingLayer [OPTIONAL]
     //     + m_graphicsLayer
     //        + m_childContainmentLayer [OPTIONAL] <-OR-> m_scrollingLayer [OPTIONAL] <-OR-> m_childTransformLayer
     //                                                     + m_scrollingContentsLayer [OPTIONAL]
     //
     // We need an ancestor clipping layer if our clipping ancestor is not our ancestor in the
     // clipping tree. Here's what that might look like.
@@ skipping 70 matching lines @@
     bool m_requiresOwnBackingStoreForAncestorReasons : 1;
     bool m_canCompositeFilters : 1;
     bool m_backgroundLayerPaintsFixedRootBackground : 1;
     bool m_needToUpdateGeometry : 1;
     bool m_needToUpdateGeometryOfAllDecendants : 1;
 };
 
 } // namespace WebCore
 
 #endif // CompositedLayerMapping_h