Refactor ShapeOutsideInfo so it isn't mutated for each line

Source/core/rendering/shapes/ShapeOutsideInfo.h

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. 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.
@@ skipping 25 matching lines @@
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/LayoutSize.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
 
 class RenderBlockFlow;
 class RenderBox;
 class FloatingObject;
 
+class ShapeOutsideDeltas FINAL {
+public:
+    ShapeOutsideDeltas()
+        : m_leftMarginBoxDelta(0)

[leviw_travelin_and_unemployed, 2014/08/15 22:42:10]

These constructors taking zeros aren't necessary, and actually are slower when
instantiating LayoutUnits than the default.

+        , m_rightMarginBoxDelta(0)
+        , m_borderBoxLineTop(0)
+        , m_lineHeight(0)
+        , m_lineOverlapsShape(false)
+        , m_isValid(false)
+    {
+    }
+
+    ShapeOutsideDeltas(LayoutUnit leftMarginBoxDelta, LayoutUnit rightMarginBoxDelta, bool lineOverlapsShape, LayoutUnit borderBoxLineTop, LayoutUnit lineHeight)
+        : m_leftMarginBoxDelta(leftMarginBoxDelta)
+        , m_rightMarginBoxDelta(rightMarginBoxDelta)
+        , m_borderBoxLineTop(borderBoxLineTop)
+        , m_lineHeight(lineHeight)
+        , m_lineOverlapsShape(lineOverlapsShape)
+        , m_isValid(true)
+    {
+    }
+
+    bool isForLine(LayoutUnit borderBoxLineTop, LayoutUnit lineHeight)
+    {
+        return m_isValid && m_borderBoxLineTop == borderBoxLineTop && m_lineHeight == lineHeight;
+    }
+
+    bool isValid() { return m_isValid; }
+    LayoutUnit leftMarginBoxDelta() { ASSERT(m_isValid); return m_leftMarginBoxDelta; }
+    LayoutUnit rightMarginBoxDelta() { ASSERT(m_isValid); return m_rightMarginBoxDelta; }
+    bool lineOverlapsShape() { ASSERT(m_isValid); return m_lineOverlapsShape; }
+
+private:
+    LayoutUnit m_leftMarginBoxDelta;
+    LayoutUnit m_rightMarginBoxDelta;
+    LayoutUnit m_borderBoxLineTop;
+    LayoutUnit m_lineHeight;
+    bool m_lineOverlapsShape;

[leviw_travelin_and_unemployed, 2014/08/15 22:42:10]

Nit: you could pack these by explicitly sizing them. I don't think we
necessarily get that for free?

+    bool m_isValid;
+};
+
 class ShapeOutsideInfo FINAL {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     void setReferenceBoxLogicalSize(LayoutSize);
 
     LayoutUnit shapeLogicalTop() const { return computedShape().shapeMarginLogicalBoundingBox().y() + logicalTopOffset(); }
     LayoutUnit shapeLogicalBottom() const { return computedShape().shapeMarginLogicalBoundingBox().maxY() + logicalTopOffset(); }
     LayoutUnit shapeLogicalLeft() const { return computedShape().shapeMarginLogicalBoundingBox().x() + logicalLeftOffset(); }
     LayoutUnit shapeLogicalRight() const { return computedShape().shapeMarginLogicalBoundingBox().maxX() + logicalLeftOffset(); }
     LayoutUnit shapeLogicalWidth() const { return computedShape().shapeMarginLogicalBoundingBox().width(); }
     LayoutUnit shapeLogicalHeight() const { return computedShape().shapeMarginLogicalBoundingBox().height(); }
 
-    LayoutUnit logicalLineTop() const { return m_referenceBoxLineTop + logicalTopOffset(); }
-    LayoutUnit logicalLineBottom() const { return m_referenceBoxLineTop + m_lineHeight + logicalTopOffset(); }
-
-    LayoutUnit leftMarginBoxDelta() const { return m_leftMarginBoxDelta; }
-    LayoutUnit rightMarginBoxDelta() const { return m_rightMarginBoxDelta; }
-    bool lineOverlapsShape() const { return m_lineOverlapsShape; }
-
     static PassOwnPtr<ShapeOutsideInfo> createInfo(const RenderBox& renderer) { return adoptPtr(new ShapeOutsideInfo(renderer)); }
     static bool isEnabledFor(const RenderBox&);
-    void updateDeltasForContainingBlockLine(const RenderBlockFlow&, const FloatingObject&, LayoutUnit lineTop, LayoutUnit lineHeight);
 
-    bool lineOverlapsShapeBounds() const
-    {
-        return computedShape().lineOverlapsShapeMarginBounds(m_referenceBoxLineTop, m_lineHeight);
-    }
+    ShapeOutsideDeltas computeDeltasForContainingBlockLine(const RenderBlockFlow&, const FloatingObject&, LayoutUnit lineTop, LayoutUnit lineHeight);
 
     static ShapeOutsideInfo& ensureInfo(const RenderBox& key)
     {
         InfoMap& infoMap = ShapeOutsideInfo::infoMap();
         if (ShapeOutsideInfo* info = infoMap.get(&key))
             return *info;
         InfoMap::AddResult result = infoMap.add(&key, ShapeOutsideInfo::createInfo(key));
         return *result.storedValue->value;
     }
     static void removeInfo(const RenderBox& key) { infoMap().remove(&key); }
     static ShapeOutsideInfo* info(const RenderBox& key) { return infoMap().get(&key); }
 
     void markShapeAsDirty() { m_shape.clear(); }
     bool isShapeDirty() { return !m_shape.get(); }
     LayoutSize shapeSize() const { return m_referenceBoxLogicalSize; }
 
     LayoutRect computedShapePhysicalBoundingBox() const;
     FloatPoint shapeToRendererPoint(FloatPoint) const;
     FloatSize shapeToRendererSize(FloatSize) const;
     const Shape& computedShape() const;
 
 protected:
     ShapeOutsideInfo(const RenderBox& renderer)
         : m_renderer(renderer)
-        , m_lineOverlapsShape(false)
     { }
 
 private:
     PassOwnPtr<Shape> createShapeForImage(StyleImage*, float shapeImageThreshold, WritingMode, float margin) const;
 
     LayoutUnit logicalTopOffset() const;
     LayoutUnit logicalLeftOffset() const;
 
     typedef HashMap<const RenderBox*, OwnPtr<ShapeOutsideInfo> > InfoMap;
     static InfoMap& infoMap()
     {
         DEFINE_STATIC_LOCAL(InfoMap, staticInfoMap, ());
         return staticInfoMap;
     }
 
-    LayoutUnit m_referenceBoxLineTop;
-    LayoutUnit m_lineHeight;
-
     const RenderBox& m_renderer;
     mutable OwnPtr<Shape> m_shape;
     LayoutSize m_referenceBoxLogicalSize;
-    LayoutUnit m_leftMarginBoxDelta;
-    LayoutUnit m_rightMarginBoxDelta;
-    LayoutUnit m_borderBoxLineTop;
-    bool m_lineOverlapsShape;
+    ShapeOutsideDeltas m_shapeOutsideDeltas;
 };
 
 }
 #endif