SharedWorker: Add WPT for testing data URL

This CL adds WPT for a worker loaded from a data URL.
This test is basically same to dedicated-worker-import-data-url.any.js

Bug: 824646
Change-Id: I43faf747c9877c431157e2a3b71d3a2bbad05130
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2016784
Commit-Queue: Eriko Kurimoto <elkurin@google.com>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735311}

third_party/blink/web_tests/external/wpt/workers/modules/shared-worker-import-data-url.any.js

+// META: global=!worker
+// META: script=/workers/modules/resources/import-test-cases.js
+
+// Imports |testCase.scriptURL| on a shared worker loaded from a data URL,
+// and waits until the list of imported modules is sent from the worker. Passes
+// if the list is equal to |testCase.expectation|.
+function import_data_url_test(testCase) {
+  promise_test(async () => {
+    // The Access-Control-Allow-Origin header is necessary because a worker
+    // loaded from a data URL has a null origin and import() on the worker
+    // without the header is blocked.
+    const importURL = new URL(testCase.scriptURL, location.href) +
+        '?pipe=header(Access-Control-Allow-Origin, *)';
+    const dataURL = `data:text/javascript,import "${importURL}";`;
+
+    const worker = new SharedWorker(dataURL, { type: 'module'});
+    worker.port.postMessage('Send message for tests from main script.');
+    const msgEvent =
+        await new Promise(resolve => worker.port.onmessage = resolve);
+    assert_array_equals(msgEvent.data, testCase.expectation);
+  }, testCase.description);
+}
+
+testCases.forEach(import_data_url_test);