bluetooth: async/await for test helper methods

This change updates the bluetooth-test.js and bluetooth-helpers.js file
to use async/await to improve readability.

Bug: 1070816
Change-Id: I26b3f66f971f73860e6f2e89ef63709b0da6d164
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2160087Reviewed-by: James Hollyer <jameshollyer@google.com>
Reviewed-by: Vincent Scheib <scheib@chromium.org>
Commit-Queue: Ovidio de Jesús Ruiz-Henríquez <odejesush@chromium.org>
Cr-Commit-Position: refs/heads/master@{#763374}

third_party/blink/web_tests/external/wpt/bluetooth/resources/bluetooth-test.js

@@ -24,12 +24,11 @@ function loadScript(path) {
  * @returns {Promise<void>} A promise chain that resolves when all scripts have
  *     finished loading.
  */
-function loadScripts(paths) {
-  let chain = Promise.resolve();
+async function loadScripts(paths) {
   for (let path of paths) {
-    chain = chain.then(() => loadScript(path));
+    await loadScript(path);
   }
-  return chain;
+  return;
 }
 
 /**
@@ -42,7 +41,7 @@ function loadScripts(paths) {
  * Bluetooth Blink Web Tests have been migrated into this repository.
  * @returns {Promise<void>} Resolves when Chromium specific setup is complete.
  */
-function performChromiumSetup() {
+async function performChromiumSetup() {
   // Make sure we are actually on Chromium with Mojo enabled.
   if (typeof Mojo === 'undefined') {
     return;
@@ -65,7 +64,7 @@ function performChromiumSetup() {
       '/js-test-resources/bluetooth/bluetooth-fake-adapter.js',
     ];
   }
-  return loadScripts([
+  await loadScripts([
     `${genPrefix}/layout_test_data/mojo/public/js/mojo_bindings.js`,
     `${genPrefix}/content/test/data/mojo_web_test_helper_test.mojom.js`,
     `${genPrefix}/device/bluetooth/public/mojom/uuid.mojom.js`,
@@ -73,19 +72,18 @@ function performChromiumSetup() {
     `${genPrefix}/device/bluetooth/public/mojom/test/fake_bluetooth.mojom.js`,
     `${genPrefix}/content/shell/common/web_test/fake_bluetooth_chooser.mojom.js`,
     `${prefix}/web-bluetooth-test.js`,
-         ].concat(extra))
-      // Call setBluetoothFakeAdapter() to clean up any fake adapters left over
-      // by legacy tests.
-      // Legacy tests that use setBluetoothFakeAdapter() sometimes fail to clean
-      // their fake adapter. This is not a problem for these tests because the
-      // next setBluetoothFakeAdapter() will clean it up anyway but it is a
-      // problem for the new tests that do not use setBluetoothFakeAdapter().
-      // TODO(https://crbug.com/569709): Remove once setBluetoothFakeAdapter is
-      // no longer used.
-      .then(
-          () => typeof setBluetoothFakeAdapter === 'undefined' ?
-              undefined :
-              setBluetoothFakeAdapter(''));
+  ].concat(extra));
+
+  // Call setBluetoothFakeAdapter() to clean up any fake adapters left over by
+  // legacy tests. Legacy tests that use setBluetoothFakeAdapter() sometimes
+  // fail to clean their fake adapter. This is not a problem for these tests
+  // because the next setBluetoothFakeAdapter() will clean it up anyway but it
+  // is a problem for the new tests that do not use setBluetoothFakeAdapter().
+  // TODO(https://crbug.com/569709): Remove once setBluetoothFakeAdapter is no
+  // longer used.
+  if (typeof setBluetoothFakeAdapter !== 'undefined') {
+    setBluetoothFakeAdapter('');
+  }
 }
 
 /**
@@ -99,16 +97,13 @@ function performChromiumSetup() {
  *     rejects if the test failed.
  */
 function bluetooth_test(test_function, name, properties) {
-  Promise.resolve().then(
-      () => promise_test(
-          t => Promise
-                   .resolve()
+  return promise_test(async (t) => {
     // Trigger Chromium-specific setup.
-                   .then(performChromiumSetup)
-                   .then(() => test_function(t))
-                   .then(() => navigator.bluetooth.test.allResponsesConsumed())
-                   .then(consumed => assert_true(consumed)),
-          name, properties));
+    await performChromiumSetup();
+    await test_function(t);
+    let consumed = await navigator.bluetooth.test.allResponsesConsumed();
+    assert_true(consumed);
+  }, name, properties);
 }
 
 /**
@@ -138,12 +133,11 @@ function waitForDocumentReady() {
  * @returns {Promise<*>} Resolves when the user activation has been simulated
  *     with the result of |callback|.
  */
-function callWithTrustedClick(callback) {
-  return waitForDocumentReady().then(() => new Promise(resolve => {
-                                       let button =
-                                           document.createElement('button');
-                                       button.textContent =
-                                           'click to continue test';
+async function callWithTrustedClick(callback) {
+  await waitForDocumentReady();
+  return new Promise(resolve => {
+    let button = document.createElement('button');
+    button.textContent = 'click to continue test';
     button.style.display = 'block';
     button.style.fontSize = '20px';
     button.style.padding = '10px';
@@ -153,7 +147,7 @@ function callWithTrustedClick(callback) {
     };
     document.body.appendChild(button);
     test_driver.click(button);
-                                     }));
+  });
 }
 
 /**
@@ -356,7 +350,7 @@ function assert_promise_resolves_after_event(
  * @returns {Promise<void>} Resolves if no events were fired.
  */
 function assert_no_events(object, event_name) {
-  return new Promise((resolve, reject) => {
+  return new Promise((resolve) => {
     let event_listener = (e) => {
       object.removeEventListener(event_name, event_listener);
       assert_unreached('Object should not fire an event.');