Refactor ShapeOutsideInfo so it isn't mutated for each line

Source/core/rendering/shapes/ShapeOutsideInfo.cpp

Index: Source/core/rendering/shapes/ShapeOutsideInfo.cpp
diff --git a/Source/core/rendering/shapes/ShapeOutsideInfo.cpp b/Source/core/rendering/shapes/ShapeOutsideInfo.cpp
index 81bae101e3385ce8671fecbda285b9393ac73a62..b4c02fc710d3d854e2a713b91282e5cdceb77a4a 100644
--- a/Source/core/rendering/shapes/ShapeOutsideInfo.cpp
+++ b/Source/core/rendering/shapes/ShapeOutsideInfo.cpp
@@ -274,42 +274,41 @@ bool ShapeOutsideInfo::isEnabledFor(const RenderBox& box)
 
     return false;
 }
-void ShapeOutsideInfo::updateDeltasForContainingBlockLine(const RenderBlockFlow& containingBlock, const FloatingObject& floatingObject, LayoutUnit lineTop, LayoutUnit lineHeight)
+ShapeOutsideDeltas ShapeOutsideInfo::computeDeltasForContainingBlockLine(const RenderBlockFlow& containingBlock, const FloatingObject& floatingObject, LayoutUnit lineTop, LayoutUnit lineHeight)
 {
     ASSERT(lineHeight >= 0);
 
     LayoutUnit borderBoxTop = containingBlock.logicalTopForFloat(&floatingObject) + containingBlock.marginBeforeForChild(&m_renderer);
     LayoutUnit borderBoxLineTop = lineTop - borderBoxTop;
 
-    if (isShapeDirty() || m_borderBoxLineTop != borderBoxLineTop || m_lineHeight != lineHeight) {
-        m_borderBoxLineTop = borderBoxLineTop;
-        m_referenceBoxLineTop = borderBoxLineTop - logicalTopOffset();
-        m_lineHeight = lineHeight;
-
+    if (isShapeDirty() || !m_shapeOutsideDeltas.isForLine(borderBoxLineTop, lineHeight)) {
+        LayoutUnit referenceBoxLineTop = borderBoxLineTop - logicalTopOffset();
         LayoutUnit floatMarginBoxWidth = containingBlock.logicalWidthForFloat(&floatingObject);
 
-        if (lineOverlapsShapeBounds()) {
+        if (computedShape().lineOverlapsShapeMarginBounds(referenceBoxLineTop, lineHeight)) {
             LineSegment segment = computedShape().getExcludedInterval((borderBoxLineTop - logicalTopOffset()), std::min(lineHeight, shapeLogicalBottom() - borderBoxLineTop));
             if (segment.isValid) {
                 LayoutUnit logicalLeftMargin = containingBlock.style()->isLeftToRightDirection() ? containingBlock.marginStartForChild(&m_renderer) : containingBlock.marginEndForChild(&m_renderer);
                 LayoutUnit rawLeftMarginBoxDelta = segment.logicalLeft + logicalLeftOffset() + logicalLeftMargin;
-                m_leftMarginBoxDelta = clampToLayoutUnit(rawLeftMarginBoxDelta, LayoutUnit(), floatMarginBoxWidth);
+                LayoutUnit leftMarginBoxDelta = clampTo<LayoutUnit>(rawLeftMarginBoxDelta, LayoutUnit(), floatMarginBoxWidth);
 
                 LayoutUnit logicalRightMargin = containingBlock.style()->isLeftToRightDirection() ? containingBlock.marginEndForChild(&m_renderer) : containingBlock.marginStartForChild(&m_renderer);
                 LayoutUnit rawRightMarginBoxDelta = segment.logicalRight + logicalLeftOffset() - containingBlock.logicalWidthForChild(&m_renderer) - logicalRightMargin;
-                m_rightMarginBoxDelta = clampToLayoutUnit(rawRightMarginBoxDelta, -floatMarginBoxWidth, LayoutUnit());
-                m_lineOverlapsShape = true;
-                return;
+                LayoutUnit rightMarginBoxDelta = clampTo<LayoutUnit>(rawRightMarginBoxDelta, -floatMarginBoxWidth, LayoutUnit());
+
+                m_shapeOutsideDeltas = ShapeOutsideDeltas(leftMarginBoxDelta, rightMarginBoxDelta, true, borderBoxLineTop, lineHeight);
+                return m_shapeOutsideDeltas;
             }
         }
 
         // Lines that do not overlap the shape should act as if the float
         // wasn't there for layout purposes. So we set the deltas to remove the
         // entire width of the float.
-        m_leftMarginBoxDelta = floatMarginBoxWidth;
-        m_rightMarginBoxDelta = -floatMarginBoxWidth;
-        m_lineOverlapsShape = false;
+        m_shapeOutsideDeltas = ShapeOutsideDeltas(floatMarginBoxWidth, -floatMarginBoxWidth, false, borderBoxLineTop, lineHeight);
+        return m_shapeOutsideDeltas;
     }
+
+    return m_shapeOutsideDeltas;
 }
 
 LayoutRect ShapeOutsideInfo::computedShapePhysicalBoundingBox() const