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

Source/core/rendering/svg/RenderSVGResourceMarker.cpp

Index: Source/core/rendering/svg/RenderSVGResourceMarker.cpp
diff --git a/Source/core/rendering/svg/RenderSVGResourceMarker.cpp b/Source/core/rendering/svg/RenderSVGResourceMarker.cpp
index d338016966fc9792ba3772d459d14c450716b86d..b2700df79a645e0f6d85308f3be76f5c08badb97 100644
--- a/Source/core/rendering/svg/RenderSVGResourceMarker.cpp
+++ b/Source/core/rendering/svg/RenderSVGResourceMarker.cpp
@@ -115,17 +115,21 @@ float RenderSVGResourceMarker::angle() const
     return angle;
 }
 
-AffineTransform RenderSVGResourceMarker::markerTransformation(const FloatPoint& origin, float autoAngle, float strokeWidth) const
+AffineTransform RenderSVGResourceMarker::markerTransformation(const FloatPoint& origin, float autoAngle, float strokeWidth, bool isStartMarker) const
 {
     SVGMarkerElement* marker = toSVGMarkerElement(element());
     ASSERT(marker);
 
     float markerAngle = angle();
     bool useStrokeWidth = marker->markerUnits()->currentValue()->enumValue() == SVGMarkerUnitsStrokeWidth;
-
+    if (markerAngle == -1) {
+        markerAngle = autoAngle;
+        if (isStartMarker && marker->orientType()->currentValue()->enumValue() == SVGMarkerOrientAutoStartReverse)
+            markerAngle += 180;

[fs, 2014/09/09 12:18:21]

I'm curious if this (adjustment) would be nicer in the SVGMarkerData-helper
(i.e. pass an auto-start-reverse flag to it, and then compute different
(auto-)angle in currentAngle(StartMarker) instead. That ought to cut
RenderSVGResourceMarker out of the patch entirely.

+    }
     AffineTransform transform;
     transform.translate(origin.x(), origin.y());
-    transform.rotate(markerAngle == -1 ? autoAngle : markerAngle);
+    transform.rotate(markerAngle);
     transform = markerContentTransformation(transform, referencePoint(), useStrokeWidth ? strokeWidth : -1);
     return transform;
 }