Make compositing updates 30.7% faster for calculator

Source/core/rendering/RenderLayer.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 462 matching lines @@
     void setOffsetFromSquashingLayerOrigin(IntSize offset) { m_compositingProperties.offsetFromSquashingLayerOrigin = offset; }
     IntSize offsetFromSquashingLayerOrigin() const { return m_compositingProperties.offsetFromSquashingLayerOrigin; }
 
     bool scrollsOverflow() const;
 
     bool hasDirectReasonsForCompositing() const { return compositingReasons() & CompositingReasonComboAllDirectReasons; }
     CompositingReasons styleDeterminedCompositingReasons() const { return compositingReasons() & CompositingReasonComboAllStyleDeterminedReasons; }
 
     void clearAncestorDependentPropertyCache();
 
-    const IntRect& absoluteBoundingBox() { ASSERT(!m_needsToRecomputeBounds); return m_absoluteBoundingBox; }
-    void setAbsoluteBoundingBox(const IntRect&);
-    void clearNeedsToRecomputeBounds();
-    bool needsToRecomputeBounds() { return m_needsToRecomputeBounds; }
+    class AncestorDependentProperties {
+    public:
+        IntRect absoluteBoundingBox;
+    };
+
+    void setNeedsToUpdateAncestorDependentProperties();
+    bool childNeedsToUpdateAncestorDependantProperties() const { return m_childNeedsToUpdateAncestorDependantProperties; }
+    bool needsToUpdateAncestorDependentProperties() const { return m_needsToUpdateAncestorDependentProperties; }
+
+    void updateAncestorDependentProperties(const AncestorDependentProperties&);
+    void clearChildNeedsToUpdateAncestorDependantProperties();
+
+    const AncestorDependentProperties& ancestorDependentProperties() { ASSERT(!m_needsToUpdateAncestorDependentProperties); return m_ancestorDependentProperties; }
 
 private:
+    // FIXME: Merge with AncestorDependentProperties.
     class AncestorDependentPropertyCache {
         WTF_MAKE_NONCOPYABLE(AncestorDependentPropertyCache);
     public:
         AncestorDependentPropertyCache();
 
         RenderLayer* ancestorCompositedScrollingLayer() const;
         void setAncestorCompositedScrollingLayer(RenderLayer*);
 
         RenderLayer* scrollParent() const;
         void setScrollParent(RenderLayer*);
@@ skipping 207 matching lines @@
     unsigned m_has3DTransformedDescendant : 1;
 
     unsigned m_containsDirtyOverlayScrollbars : 1;
 
     // This is an optimization added for <table>.
     // Currently cells do not need to update their repaint rectangles when scrolling. This also
     // saves a lot of time when scrolling on a table.
     const unsigned m_canSkipRepaintRectsUpdateOnScroll : 1;
 
     unsigned m_hasFilterInfo : 1;
-    unsigned m_needsToRecomputeBounds : 1;
+    unsigned m_needsToUpdateAncestorDependentProperties : 1;
+    unsigned m_childNeedsToUpdateAncestorDependantProperties : 1;
 
     RenderLayerModelObject* m_renderer;
 
     RenderLayer* m_parent;
     RenderLayer* m_previous;
     RenderLayer* m_next;
     RenderLayer* m_first;
     RenderLayer* m_last;
 
     // Our current relative position offset.
     LayoutSize m_offsetForInFlowPosition;
 
     // Our (x,y) coordinates are in our parent layer's coordinate space.
     LayoutPoint m_topLeft;
 
     // The layer's width/height
     IntSize m_layerSize;
 
     // Cached normal flow values for absolute positioned elements with static left/top values.
     LayoutUnit m_staticInlinePosition;
     LayoutUnit m_staticBlockPosition;
 
-    IntRect m_absoluteBoundingBox;
-
     OwnPtr<TransformationMatrix> m_transform;
 
     // Pointer to the enclosing RenderLayer that caused us to be paginated. It is 0 if we are not paginated.
     RenderLayer* m_enclosingPaginationLayer;
 
     // Properties that are computed while updating compositing layers. These values may be dirty/invalid if
     // compositing status is not up-to-date before using them.
     struct CompositingProperties {
         CompositingProperties()
             : hasCompositingDescendant(false)
@@ skipping 21 matching lines @@
         // The reason, if any exists, that a fixed-position layer is chosen not to be composited.
         unsigned viewportConstrainedNotCompositedReason : ViewportConstrainedNotCompositedReasonBits;
 
         // Once computed, indicates all that a layer needs to become composited using the CompositingReasons enum bitfield.
         CompositingReasons compositingReasons;
 
         // Used for invalidating this layer's contents on the squashing GraphicsLayer.
         IntSize offsetFromSquashingLayerOrigin;
     };
 
+    // FIXME: Merge m_ancestorDependentPropertyCache into m_ancestorDependentProperties;
+    AncestorDependentProperties m_ancestorDependentProperties;
+
     CompositingProperties m_compositingProperties;
 
     IntRect m_blockSelectionGapsBounds;
 
     OwnPtr<CompositedLayerMapping> m_compositedLayerMapping;
     OwnPtr<RenderLayerScrollableArea> m_scrollableArea;
 
     mutable OwnPtr<AncestorDependentPropertyCache> m_ancestorDependentPropertyCache;
 
     CompositedLayerMapping* m_groupedMapping;
 
     RenderLayerRepainter m_repainter;
     RenderLayerClipper m_clipper; // FIXME: Lazily allocate?
     OwnPtr<RenderLayerStackingNode> m_stackingNode;
     OwnPtr<RenderLayerReflectionInfo> m_reflectionInfo;
     RenderLayerBlendInfo m_blendInfo;
 };
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const WebCore::RenderLayer*);
 void showLayerTree(const WebCore::RenderObject*);
 #endif
 
 #endif // RenderLayer_h