ReadableStream: test pipe options exceptions

Coverage indicated that the case where there is an exception looking up
a pipeTo or pipeThrough option was not actually tested. Add a web
platform test to verify that exceptions are thrown and that options are
accessed in the correct order.

Change-Id: I88d889a42853ee0625cc51fe30cd119b118289b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1903169Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713362}

third_party/blink/web_tests/external/wpt/streams/piping/throwing-options.any.js

+// META: global=worker,jsshell
+
+class ThrowingOptions {
+  constructor(whatShouldThrow) {
+    this.whatShouldThrow = whatShouldThrow;
+    this.touched = [];
+  }
+
+  get preventClose() {
+    this.maybeThrow('preventClose');
+    return false;
+  }
+
+  get preventAbort() {
+    this.maybeThrow('preventAbort');
+    return false;
+  }
+
+  get preventCancel() {
+    this.maybeThrow('preventCancel');
+    return false;
+  }
+
+  get signal() {
+    this.maybeThrow('signal');
+    return undefined;
+  }
+
+  maybeThrow(forWhat) {
+    this.touched.push(forWhat);
+    if (this.whatShouldThrow === forWhat) {
+      throw new Error(this.whatShouldThrow);
+    }
+  }
+}
+
+const checkOrder = ['preventClose', 'preventAbort', 'preventCancel', 'signal'];
+
+for (let i = 0; i < checkOrder.length; ++i) {
+  const whatShouldThrow = checkOrder[i];
+  const whatShouldBeTouched = checkOrder.slice(0, i + 1);
+
+  promise_test(t => {
+    const options = new ThrowingOptions(whatShouldThrow);
+    return promise_rejects(
+               t, new Error(),
+               new ReadableStream().pipeTo(new WritableStream(), options),
+               'pipeTo should reject')
+        .then(() => assert_array_equals(
+            options.touched, whatShouldBeTouched,
+            'options should be touched in the right order'));
+  }, `pipeTo should stop after getting ${whatShouldThrow} throws`);
+
+  test(() => {
+    const options = new ThrowingOptions(whatShouldThrow);
+    assert_throws(
+        new Error(),
+        () => new ReadableStream().pipeThrough(new TransformStream(), options),
+        'pipeThrough should throw');
+    assert_array_equals(
+        options.touched, whatShouldBeTouched,
+        'options should be touched in the right order');
+  }, `pipeThrough should stop after getting ${whatShouldThrow} throws`);
+}