Add support for new canvas ellipse method.

Source/core/platform/graphics/Path.cpp

 /*
  * Copyright (C) 2003, 2006 Apple Computer, Inc.  All rights reserved.
  *                     2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2013 Google Inc. 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
@@ skipping 341 matching lines @@
         sweepDegrees += s360;
 
     m_path->arcTo(oval, startDegrees, sweepDegrees, false);
 }
 
 void Path::addRect(const FloatRect& rect)
 {
     ensureSkPath()->addRect(rect);
 }
 
+void Path::addEllipse(const FloatPoint& p, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise)
+{
+    if (!radiusX || !radiusY || startAngle == endAngle) {
+        // The ellipse is empty but we still need to draw the connecting line to start point.
+        FloatPoint p1(p.x() + radiusX * cosf(startAngle + rotation), p.y() + radiusY * sinf(startAngle + rotation));
+        if (!hasCurrentPoint())
+            moveTo(p1);
+        else if (p1 != currentPoint())
+            addLineTo(p1);
+        return;
+    }
+
+    // Add an arc after the relevant transform.
+    AffineTransform ellipseTransform = AffineTransform().rotate(rad2deg(rotation)).scale(radiusX, radiusY);
+    ASSERT(ellipseTransform.isInvertible());
+    AffineTransform inverseEllipseTransform = ellipseTransform.inverse();
+    transform(inverseEllipseTransform);
+    float unitCircleRadius = 1.;
+    addArc(inverseEllipseTransform.mapPoint(p), unitCircleRadius, startAngle, endAngle, anticlockwise);
+    transform(ellipseTransform);
+}
+
 void Path::addEllipse(const FloatRect& rect)
 {
     ensureSkPath()->addOval(rect);
 }
 
 void Path::addRoundedRect(const RoundedRect& r)
 {
     addRoundedRect(r.rect(), r.radii().topLeft(), r.radii().topRight(), r.radii().bottomLeft(), r.radii().bottomRight());
 }
 
@@ skipping 83 matching lines @@
 
     closeSubpath();
 }
 
 void Path::translate(const FloatSize& size)
 {
     ensureSkPath()->offset(WebCoreFloatToSkScalar(size.width()), WebCoreFloatToSkScalar(size.height()));
 }
 
 }