Set up scroll and clip parents

Source/core/rendering/RenderLayerBacking.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 76 matching lines @@
     // Update whether layer needs blending.
     void updateContentsOpaque();
 
     GraphicsLayer* graphicsLayer() const { return m_graphicsLayer.get(); }
 
     // Layer to clip children
     bool hasClippingLayer() const { return m_childContainmentLayer; }
     GraphicsLayer* clippingLayer() const { return m_childContainmentLayer.get(); }
 
     // Layer to get clipped by ancestor
-    bool hasAncestorClippingLayer() const { return m_ancestorClippingLayer != 0; }
+    bool hasAncestorClippingLayer() const { return m_ancestorClippingLayer; }
     GraphicsLayer* ancestorClippingLayer() const { return m_ancestorClippingLayer.get(); }
 
+    bool hasAncestorScrollClippingLayer() const { return m_ancestorScrollClippingLayer; }
+    GraphicsLayer* ancestorScrollClippingLayer() const { return m_ancestorScrollClippingLayer.get(); }
+
     bool hasContentsLayer() const { return m_foregroundLayer != 0; }
     GraphicsLayer* foregroundLayer() const { return m_foregroundLayer.get(); }
 
     GraphicsLayer* backgroundLayer() const { return m_backgroundLayer.get(); }
     bool backgroundLayerPaintsFixedRootBackground() const { return m_backgroundLayerPaintsFixedRootBackground; }
 
     bool hasScrollingLayer() const { return m_scrollingLayer; }
     GraphicsLayer* scrollingLayer() const { return m_scrollingLayer.get(); }
     GraphicsLayer* scrollingContentsLayer() const { return m_scrollingContentsLayer.get(); }
 
@@ skipping 72 matching lines @@
 private:
     void createPrimaryGraphicsLayer();
     void destroyGraphicsLayers();
 
     PassOwnPtr<GraphicsLayer> createGraphicsLayer(CompositingReasons);
 
     RenderLayerModelObject* renderer() const { return m_owningLayer->renderer(); }
     RenderLayerCompositor* compositor() const { return m_owningLayer->compositor(); }
 
     void updateInternalHierarchy();
-    bool updateClippingLayers(bool needsAncestorClip, bool needsDescendantClip);
+    bool updateClippingLayers(bool needsAncestorClip, bool needsDescendantClip, bool needsScrollClip);
     bool updateOverflowControlsLayers(bool needsHorizontalScrollbarLayer, bool needsVerticalScrollbarLayer, bool needsScrollCornerLayer);
     bool updateForegroundLayer(bool needsForegroundLayer);
     bool updateBackgroundLayer(bool needsBackgroundLayer);
     bool updateMaskLayer(bool needsMaskLayer);
     bool requiresHorizontalScrollbarLayer() const { return m_owningLayer->horizontalScrollbar(); }
     bool requiresVerticalScrollbarLayer() const { return m_owningLayer->verticalScrollbar(); }
     bool requiresScrollCornerLayer() const { return !m_owningLayer->scrollCornerAndResizerRect().isEmpty(); }
     bool updateScrollingLayers(bool scrollingLayers);
+    void updateScrollParent(RenderLayer*);
+    void updateClipParent(RenderLayer*);
     void updateDrawsContent(bool isSimpleContainer);
     void registerScrollingLayers();
 
     void setBackgroundLayerPaintsFixedRootBackground(bool);
 
     GraphicsLayerPaintingPhase paintingPhaseForPrimaryLayer() const;
 
     IntSize contentOffsetInCompostingLayer() const;
     // Result is transform origin in pixels.
     FloatPoint3D computeTransformOrigin(const IntRect& borderBox) const;
@@ skipping 29 matching lines @@
 
     bool shouldClipCompositedBounds() const;
 
     void doPaintTask(GraphicsLayerPaintInfo&, GraphicsContext*, const IntRect& clip);
 
     static CSSPropertyID graphicsLayerToCSSProperty(AnimatedPropertyID);
     static AnimatedPropertyID cssToGraphicsLayerProperty(CSSPropertyID);
 
     RenderLayer* m_owningLayer;
 
+    OwnPtr<GraphicsLayer> m_ancestorScrollClippingLayer; // Only used if we have a scroll parent, and our clipping ancestor is not our scroll parent.

[enne (OOO), 2013/09/10 23:45:01]

The code looks like it says this is used if and only if there is a scroll
parent?

[Ian Vollick, 2013/09/11 17:57:52]

It is. I've updated the comment.

     OwnPtr<GraphicsLayer> m_ancestorClippingLayer; // Only used if we are clipped by an ancestor which is not a stacking context.
     OwnPtr<GraphicsLayer> m_graphicsLayer;
     OwnPtr<GraphicsLayer> m_foregroundLayer; // Only used in cases where we need to draw the foreground separately.
     OwnPtr<GraphicsLayer> m_backgroundLayer; // Only used in cases where we need to draw the background separately.
     OwnPtr<GraphicsLayer> m_childContainmentLayer; // Only used if we have clipping on a stacking context with compositing children, or if the layer has a tile cache.
     OwnPtr<GraphicsLayer> m_maskLayer; // Only used if we have a mask.
 
     OwnPtr<GraphicsLayer> m_layerForHorizontalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForVerticalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForScrollCorner;
 
     OwnPtr<GraphicsLayer> m_scrollingLayer; // Only used if the layer is using composited scrolling.
     OwnPtr<GraphicsLayer> m_scrollingContentsLayer; // Only used if the layer is using composited scrolling.
 
-    uint64_t m_scrollLayerID;
-
     IntRect m_compositedBounds;
 
     bool m_artificiallyInflatedBounds; // bounds had to be made non-zero to make transform-origin work
     bool m_boundsConstrainedByClipping;
     bool m_isMainFrameRenderViewLayer;
     bool m_requiresOwnBackingStore;
     bool m_canCompositeFilters;
     bool m_backgroundLayerPaintsFixedRootBackground;
 };
 
 } // namespace WebCore
 
 #endif // RenderLayerBacking_h