[SVG2] Add support for marker orient="auto-start-reverse".

Source/core/rendering/svg/SVGMarkerData.h

 /*
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 29 matching lines @@
     {
     }
 
     SVGMarkerType type;
     FloatPoint origin;
     float angle;
 };
 
 class SVGMarkerData {
 public:
-    SVGMarkerData(Vector<MarkerPosition>& positions)
+    SVGMarkerData(Vector<MarkerPosition>& positions, bool autoStartReverse)
         : m_positions(positions)
         , m_elementIndex(0)
+        , m_autoStartReverse(autoStartReverse)
     {
     }
 
     static void updateFromPathElement(void* info, const PathElement* element)
     {
         SVGMarkerData* markerData = static_cast<SVGMarkerData*>(info);
 
         // First update the outslope for the previous element.
         markerData->updateOutslope(element->points[0]);
 
@@ skipping 18 matching lines @@
     {
         // For details of this calculation, see: http://www.w3.org/TR/SVG/single-page.html#painting-MarkerElement
         FloatPoint inSlope(m_inslopePoints[1] - m_inslopePoints[0]);
         FloatPoint outSlope(m_outslopePoints[1] - m_outslopePoints[0]);
 
         double inAngle = rad2deg(inSlope.slopeAngleRadians());
         double outAngle = rad2deg(outSlope.slopeAngleRadians());
 
         switch (type) {
         case StartMarker:
+            if (m_autoStartReverse)
+                outAngle += 180;
             return narrowPrecisionToFloat(outAngle);
         case MidMarker:
             // WK193015: Prevent bugs due to angles being non-continuous.
             if (fabs(inAngle - outAngle) > 180)
                 inAngle += 360;
             return narrowPrecisionToFloat((inAngle + outAngle) / 2);
         case EndMarker:
             return narrowPrecisionToFloat(inAngle);
         }
 
@@ skipping 39 matching lines @@
         m_inslopePoints[0] = m_origin;
         m_inslopePoints[1] = point;
     }
 
     Vector<MarkerPosition>& m_positions;
     unsigned m_elementIndex;
     FloatPoint m_origin;
     FloatPoint m_subpathStart;
     FloatPoint m_inslopePoints[2];
     FloatPoint m_outslopePoints[2];
+    bool m_autoStartReverse;
 };
 
 }
 
 #endif // SVGMarkerData_h