Add support for new canvas ellipse method.

Source/core/platform/graphics/Path.cpp

Index: Source/core/platform/graphics/Path.cpp
diff --git a/Source/core/platform/graphics/Path.cpp b/Source/core/platform/graphics/Path.cpp
index 57479a3b747535e0324b7ff1123f0a12c21f830a..03c87c28e4b49e48e34321ec05c8f856c3bf397c 100644
--- a/Source/core/platform/graphics/Path.cpp
+++ b/Source/core/platform/graphics/Path.cpp
@@ -359,6 +359,28 @@ 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);