Remove the HasOwnBackingButPaintsIntoAncestor compositing state.

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 98 matching lines @@
     GraphicsLayer* parentForSublayers() const;
     GraphicsLayer* childForSuperlayers() const;
 
     GraphicsLayer* childTransformLayer() const { return m_childTransformLayer.get(); }
 
     GraphicsLayer* squashingContainmentLayer() const { return m_squashingContainmentLayer.get(); }
     GraphicsLayer* squashingLayer() const { return m_squashingLayer.get(); }
     // Contains the bottommost layer in the hierarchy that can contain the children transform.
     GraphicsLayer* layerForChildrenTransform() const;
 
-    // Returns true for a composited layer that has no backing store of its own, so
-    // paints into some ancestor layer.
-    bool paintsIntoCompositedAncestor() const { return !(m_requiresOwnBackingStoreForAncestorReasons || m_requiresOwnBackingStoreForIntrinsicReasons); }
-
-    // Updates whether a backing store is needed based on the layer's compositing ancestor's
-    // properties; returns true if the need for a backing store for ancestor reasons changed.
-    bool updateRequiresOwnBackingStoreForAncestorReasons(const RenderLayer* compositingAncestor);
-
-    // Updates whether a backing store is needed for intrinsic reasons (that is, based on the
-    // layer's own properties or compositing reasons); returns true if the intrinsic need for
-    // a backing store changed.
-    bool updateRequiresOwnBackingStoreForIntrinsicReasons();
-
     void setSquashingContentsNeedDisplay();
     void setContentsNeedDisplay();
     // r is in the coordinate space of the layer's render object
     void setContentsNeedDisplayInRect(const LayoutRect&, PaintInvalidationReason);
 
     // Notification from the renderer that its content changed.
     void contentChanged(ContentChangeType);
 
     LayoutRect compositedBounds() const { return m_compositedBounds; }
     IntRect pixelSnappedCompositedBounds() const;
@@ skipping 272 matching lines @@
     Vector<GraphicsLayerPaintInfo> m_squashedLayers;
     LayoutPoint m_squashingLayerOffsetFromTransformedAncestor;
 
     LayoutRect m_compositedBounds;
 
     LayoutSize m_contentOffsetInCompositingLayer;
     unsigned m_contentOffsetInCompositingLayerDirty : 1;
 
     unsigned m_pendingUpdateScope : 2;
     unsigned m_isMainFrameRenderViewLayer : 1;
-    unsigned m_requiresOwnBackingStoreForIntrinsicReasons : 1;
-    unsigned m_requiresOwnBackingStoreForAncestorReasons : 1;
+
     unsigned m_backgroundLayerPaintsFixedRootBackground : 1;
     unsigned m_scrollingContentsAreEmpty : 1;
 };
 
 } // namespace blink
 
 #endif // CompositedLayerMapping_h