Add support for new canvas ellipse method.

LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js

Index: LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js
diff --git a/LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js b/LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js
index 576a6948f6fd7719e641236201e8e2cdebd0eaf9..0ffca0b3084f341ab157adccd4f7b528669b641e 100644
--- a/LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js
+++ b/LayoutTests/fast/canvas/script-tests/canvas-arc-connecting-line.js
@@ -5,16 +5,13 @@ document.body.appendChild(canvas)
 canvas.setAttribute('width', '300');
 canvas.setAttribute('height', '300');
 var ctx = canvas.getContext('2d');
-function deg2rad(x) {
-  return x * 3.141592653589 / 180;
-}
 ctx.fillStyle = '#0f0';
 ctx.fillRect(0, 0, canvas.width, canvas.height);
 ctx.lineJoin = 'bevel';
 ctx.lineWidth = 12;
 ctx.beginPath();
-ctx.arc(200, 50, 40, deg2rad(90), deg2rad(-90), false);
-ctx.arc(100, 50, 40, deg2rad(90), deg2rad(-90), false);
+ctx.arc(200, 50, 40, Math.PI / 2, -Math.PI / 2, false);
+ctx.arc(100, 50, 40, Math.PI / 2, -Math.PI / 2, false);
 ctx.stroke();
 
 var imageData = ctx.getImageData(0, 0, 1, 1);