Add offscreen-canvas to the list of wpt directories to skip.

third_party/WebKit/LayoutTests/imported/wpt/offscreen-canvas/fill-and-stroke-styles/2d.pattern.basic.zerocanvas.worker.js

-// DO NOT EDIT! This test has been generated by tools/gentest.py.
-// OffscreenCanvas test in a worker:2d.pattern.basic.zerocanvas
-// Description:
-// Note:
-
-importScripts("/resources/testharness.js");
-importScripts("/common/canvas-tests.js");
-
-var t = async_test("");
-t.step(function() {
-
-var offscreenCanvas = new OffscreenCanvas(100, 50);
-var ctx = offscreenCanvas.getContext('2d');
-
-offscreenCanvas.width = 0;
-offscreenCanvas.height = 10;
-_assertSame(offscreenCanvas.width, 0, "offscreenCanvas.width", "0");
-_assertSame(offscreenCanvas.height, 10, "offscreenCanvas.height", "10");
-assert_throws("INVALID_STATE_ERR", function() { ctx.createPattern(offscreenCanvas, 'repeat'); });
-offscreenCanvas.width = 10;
-offscreenCanvas.height = 0;
-_assertSame(offscreenCanvas.width, 10, "offscreenCanvas.width", "10");
-_assertSame(offscreenCanvas.height, 0, "offscreenCanvas.height", "0");
-assert_throws("INVALID_STATE_ERR", function() { ctx.createPattern(offscreenCanvas, 'repeat'); });
-offscreenCanvas.width = 0;
-offscreenCanvas.height = 0;
-_assertSame(offscreenCanvas.width, 0, "offscreenCanvas.width", "0");
-_assertSame(offscreenCanvas.height, 0, "offscreenCanvas.height", "0");
-assert_throws("INVALID_STATE_ERR", function() { ctx.createPattern(offscreenCanvas, 'repeat'); });
-
-t.done();
-
-});
-done();