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

third_party/WebKit/LayoutTests/imported/wpt/offscreen-canvas/the-offscreen-canvas/initial.reset.pattern.worker.js

-// DO NOT EDIT! This test has been generated by tools/gentest.py.
-// OffscreenCanvas test in a worker:initial.reset.pattern
-// Description:Resetting the canvas state does not invalidate any existing patterns
-// Note:
-
-importScripts("/resources/testharness.js");
-importScripts("/common/canvas-tests.js");
-
-var t = async_test("Resetting the canvas state does not invalidate any existing patterns");
-t.step(function() {
-
-var offscreenCanvas = new OffscreenCanvas(100, 50);
-var ctx = offscreenCanvas.getContext('2d');
-
-offscreenCanvas.width = 30;
-ctx.fillStyle = '#0f0';
-ctx.fillRect(0, 0, 30, 50);
-var p = ctx.createPattern(offscreenCanvas, 'repeat-x');
-offscreenCanvas.width = 100;
-ctx.fillStyle = '#f00';
-ctx.fillRect(0, 0, 100, 50);
-ctx.fillStyle = p;
-ctx.fillRect(0, 0, 100, 50);
-_assertPixel(offscreenCanvas, 50,25, 0,255,0,255, "50,25", "0,255,0,255");
-
-t.done();
-
-});
-done();