[WPT] Microtasks around importScripts()

Bug: 1111134
Change-Id: I89c6b229c8871814faabadd08e3963adbe66e53e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2348239Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797197}

third_party/blink/web_tests/external/wpt/html/semantics/scripting-1/the-script-element/microtasks/checkpoint-importScripts.any.js

+// META: global=dedicatedworker,sharedworker
+
+// The `then` handlers for `Promise.resolve()` are evaluated in the first
+// microtasks checkpoint after `Promise.resolve()`.
+
+// ----------------------------------------------------------------
+// Check when microtasks checkpoint is performed around importScripts().
+
+// The expectation is: the `then` handlers are evaluated after the script
+// calling importScripts() is finished, not immediately after importScripts().
+// Although #clean-up-after-running-script is executed as a part of
+// #run-a-classic-script for importScripts()ed scripts, but at that time
+// microtasks checkpoint is NOT performed because JavaScript execution context
+// stack is not empty.
+
+self.log = [];
+
+// Microtasks should be executed before
+// #run-a-classic-script/#run-a-module-script is completed, and thus before
+// script evaluation scheduled by setTimeout().
+async_test(t => {
+  self.addEventListener('error',
+      t.unreached_func('error event should not be fired'));
+
+  t.step_timeout(() => {
+      assert_array_equals(log, [
+          'importScripts()ed script',
+          'catch',
+          'promise'
+        ]);
+      t.done();
+    },
+    0);
+}, "Promise resolved during importScripts()");
+
+try {
+  importScripts('resources/resolve-then-throw.js');
+} catch (e) {
+  self.log.push('catch');
+}

third_party/blink/web_tests/external/wpt/html/semantics/scripting-1/the-script-element/microtasks/resources/resolve-then-throw.js

+self.log.push('importScripts()ed script');
+Promise.resolve().then(() => self.log.push('promise'));
+throw new Error('foo');