[webnfc] Make NDEFReader#scan() return a Promise

Previously NDEFReader#scan() returns void and an NDEFErrorEvent will be
dispatched in case that the scan operation cannot be started
successfully.

This is not a well accepted pattern, and also to align with
NDEFWriter#push(), this CL makes NDEFReader#scan() return a Promise
instead.

Note that now NDEFErrorEvent is only used to notify Mojo disconnection,
a follow-up CL will remove it completely by using ErrorEvent instead.

The spec change:
https://github.com/w3c/web-nfc/pull/398
https://github.com/w3c/web-nfc/pull/432

BUG=520391

Change-Id: I1477258ab70f7e40da31ea8795d63125b6a13af0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899586
Commit-Queue: Leon Han <leon.han@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716904}

third_party/blink/renderer/modules/nfc/ndef_reader.cc

@@ -7,6 +7,7 @@
 #include <utility>
 
 #include "services/device/public/mojom/nfc.mojom-blink.h"
+#include "third_party/blink/renderer/bindings/core/v8/script_promise_resolver.h"
 #include "third_party/blink/renderer/core/dom/abort_signal.h"
 #include "third_party/blink/renderer/modules/event_target_modules.h"
 #include "third_party/blink/renderer/modules/nfc/ndef_error_event.h"
@@ -19,6 +20,19 @@
 
 namespace blink {
 
+namespace {
+
+void OnScanRequestCompleted(ScriptPromiseResolver* resolver,
+                            device::mojom::blink::NDEFErrorPtr error) {
+  if (error) {
+    resolver->Reject(NDEFErrorTypeToDOMException(error->error_type));
+    return;
+  }
+  resolver->Resolve();
+}
+
+}  // namespace
+
 // static
 NDEFReader* NDEFReader::Create(ExecutionContext* context) {
   return MakeGarbageCollected<NDEFReader>(context);
@@ -47,39 +61,70 @@ bool NDEFReader::HasPendingActivity() const {
 }
 
 // https://w3c.github.io/web-nfc/#the-scan-method
-void NDEFReader::scan(const NDEFScanOptions* options) {
-  if (!CheckSecurity())
-    return;
+ScriptPromise NDEFReader::scan(ScriptState* script_state,
+                               const NDEFScanOptions* options,
+                               ExceptionState& exception_state) {
+  ExecutionContext* execution_context = GetExecutionContext();
+  // https://w3c.github.io/web-nfc/#security-policies
+  // WebNFC API must be only accessible from top level browsing context.
+  if (!execution_context || !To<Document>(execution_context)->IsInMainFrame()) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kNotAllowedError,
+                                      "NFC interfaces are only avaliable "
+                                      "in a top-level browsing context");
+    return ScriptPromise();
+  }
 
-  if (options->hasSignal()) {
-    // 6. If reader.[[Signal]]'s aborted flag is set, then return.
-    if (options->signal()->aborted())
-      return;
-
-    // 7. If reader.[[Signal]] is not null, then add the following abort steps
-    // to reader.[[Signal]]:
-    options->signal()->AddAlgorithm(
-        WTF::Bind(&NDEFReader::Abort, WrapPersistent(this)));
+  // 7. If reader.[[Signal]]'s aborted flag is set, then reject p with a
+  // "AbortError" DOMException and return p.
+  if (options->hasSignal() && options->signal()->aborted()) {
+    exception_state.ThrowDOMException(DOMExceptionCode::kAbortError,
+                                      "The NFC operation was cancelled.");
+    return ScriptPromise();
   }
 
-  // Step 8.4, if the url is not an empty string and it is not a valid URL
-  // pattern, fire a NDEFErrorEvent with "SyntaxError" DOMException, then
-  // return.
+  // 9.4 If the reader.[[Id]] is not an empty string and it is not a valid URL
+  // pattern, then reject p with a "SyntaxError" DOMException and return p.
+  // TODO(https://crbug.com/520391): Instead of NDEFScanOptions#url, introduce
+  // and use NDEFScanOptions#id to do the filtering after we add support for
+  // writing NDEFRecord#id.
   if (options->hasURL() && !options->url().IsEmpty()) {
     KURL pattern_url(options->url());
     if (!pattern_url.IsValid() || pattern_url.Protocol() != "https") {
-      DispatchEvent(*MakeGarbageCollected<NDEFErrorEvent>(
-          event_type_names::kError, MakeGarbageCollected<DOMException>(
-                                        DOMExceptionCode::kSyntaxError,
-                                        "Invalid URL pattern was provided.")));
-      return;
+      exception_state.ThrowDOMException(DOMExceptionCode::kSyntaxError,
+                                        "Invalid URL pattern was provided.");
+      return ScriptPromise();
     }
   }
 
-  GetNfcProxy()->StartReading(this, options);
+  // TODO(https://crbug.com/520391): With the note in
+  // https://w3c.github.io/web-nfc/#the-ndefreader-and-ndefwriter-objects,
+  // successive invocations of NDEFReader.scan() with new options should replace
+  // existing filters. For now we just reject this new scan() when there is an
+  // ongoing filter active.
+  if (GetNfcProxy()->IsReading(this)) {
+    exception_state.ThrowDOMException(
+        DOMExceptionCode::kInvalidStateError,
+        "There is already a scan() operation ongoing.");
+    return ScriptPromise();
+  }
+
+  resolver_ = MakeGarbageCollected<ScriptPromiseResolver>(script_state);
+  // 8. If reader.[[Signal]] is not null, then add the following abort steps to
+  // reader.[[Signal]]:
+  if (options->hasSignal()) {
+    options->signal()->AddAlgorithm(WTF::Bind(&NDEFReader::Abort,
+                                              WrapPersistent(this),
+                                              WrapPersistent(resolver_.Get())));
+  }
+
+  GetNfcProxy()->StartReading(
+      this, options,
+      WTF::Bind(&OnScanRequestCompleted, WrapPersistent(resolver_.Get())));
+  return resolver_->Promise();
 }
 
 void NDEFReader::Trace(blink::Visitor* visitor) {
+  visitor->Trace(resolver_);
   EventTargetWithInlineData::Trace(visitor);
   ActiveScriptWrappable::Trace(visitor);
   ContextLifecycleObserver::Trace(visitor);
@@ -98,29 +143,31 @@ void NDEFReader::OnError(device::mojom::blink::NDEFErrorType error) {
       event_type_names::kError, NDEFErrorTypeToDOMException(error)));
 }
 
-void NDEFReader::ContextDestroyed(ExecutionContext*) {
-  GetNfcProxy()->StopReading(this);
+void NDEFReader::OnMojoConnectionError() {
+  // If |resolver_| has already settled this rejection is silently ignored.
+  if (resolver_) {
+    resolver_->Reject(NDEFErrorTypeToDOMException(
+        device::mojom::blink::NDEFErrorType::NOT_SUPPORTED));
+  }
+  // Dispatches an error event.
+  OnError(device::mojom::blink::NDEFErrorType::NOT_SUPPORTED);
 }
 
-void NDEFReader::Abort() {
+void NDEFReader::ContextDestroyed(ExecutionContext*) {
+  // If |resolver_| has already settled this rejection is silently ignored.
+  if (resolver_) {
+    resolver_->Reject(MakeGarbageCollected<DOMException>(
+        DOMExceptionCode::kAbortError,
+        "The execution context is going to be gone."));
+  }
   GetNfcProxy()->StopReading(this);
 }
 
-bool NDEFReader::CheckSecurity() {
-  ExecutionContext* execution_context = GetExecutionContext();
-  if (!execution_context)
-    return false;
-  // https://w3c.github.io/web-nfc/#security-policies
-  // WebNFC API must be only accessible from top level browsing context.
-  if (!To<Document>(execution_context)->IsInMainFrame()) {
-    DispatchEvent(*MakeGarbageCollected<NDEFErrorEvent>(
-        event_type_names::kError,
-        MakeGarbageCollected<DOMException>(DOMExceptionCode::kNotAllowedError,
-                                           "NFC interfaces are only avaliable "
-                                           "in a top-level browsing context")));
-    return false;
-  }
-  return true;
+void NDEFReader::Abort(ScriptPromiseResolver* resolver) {
+  // If |resolver| has already settled this rejection is silently ignored.
+  resolver->Reject(MakeGarbageCollected<DOMException>(
+      DOMExceptionCode::kAbortError, "The NFC operation was cancelled."));
+  GetNfcProxy()->StopReading(this);
 }
 
 NFCProxy* NDEFReader::GetNfcProxy() const {

third_party/blink/renderer/modules/nfc/ndef_reader.h

@@ -7,6 +7,7 @@
 
 #include "services/device/public/mojom/nfc.mojom-blink-forward.h"
 #include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h"
+#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
 #include "third_party/blink/renderer/core/dom/events/event_target.h"
 #include "third_party/blink/renderer/core/execution_context/context_lifecycle_observer.h"
 #include "third_party/blink/renderer/modules/modules_export.h"
@@ -17,6 +18,7 @@ namespace blink {
 class ExecutionContext;
 class NFCProxy;
 class NDEFScanOptions;
+class ScriptPromiseResolver;
 
 class MODULES_EXPORT NDEFReader : public EventTargetWithInlineData,
                                   public ActiveScriptWrappable<NDEFReader>,
@@ -39,24 +41,30 @@ class MODULES_EXPORT NDEFReader : public EventTargetWithInlineData,
 
   DEFINE_ATTRIBUTE_EVENT_LISTENER(error, kError)
   DEFINE_ATTRIBUTE_EVENT_LISTENER(reading, kReading)
-  void scan(const NDEFScanOptions*);
+  ScriptPromise scan(ScriptState*, const NDEFScanOptions*, ExceptionState&);
 
   void Trace(blink::Visitor*) override;
 
   // Called by NFCProxy for dispatching events.
   virtual void OnReading(const String& serial_number,
-                         const device::mojom::blink::NDEFMessage& message);
-  virtual void OnError(device::mojom::blink::NDEFErrorType error);
+                         const device::mojom::blink::NDEFMessage&);
+  virtual void OnError(device::mojom::blink::NDEFErrorType);
+
+  // Called by NFCProxy for notification about connection error.
+  void OnMojoConnectionError();
 
  private:
   // ContextLifecycleObserver overrides.
   void ContextDestroyed(ExecutionContext*) override;
 
-  void Abort();
+  void Abort(ScriptPromiseResolver*);
 
   NFCProxy* GetNfcProxy() const;
 
-  bool CheckSecurity();
+  // |resolver_| is kept here to handle Mojo connection failures because in that
+  // case the callback passed to Watch() won't be called and
+  // mojo::WrapCallbackWithDefaultInvokeIfNotRun() is forbidden in Blink.
+  Member<ScriptPromiseResolver> resolver_;
 };
 
 }  // namespace blink

third_party/blink/renderer/modules/nfc/ndef_reader.idl

@@ -15,5 +15,6 @@
     attribute EventHandler onreading;
     attribute EventHandler onerror;
 
-    void scan(optional NDEFScanOptions options={});
+    [CallWith=ScriptState, RaisesException] Promise<void> scan(
+        optional NDEFScanOptions options={});
 };

third_party/blink/renderer/modules/nfc/nfc_proxy.cc

@@ -52,16 +52,16 @@ void NFCProxy::Trace(blink::Visitor* visitor) {
 }
 
 void NFCProxy::StartReading(NDEFReader* reader,
-                            const NDEFScanOptions* options) {
+                            const NDEFScanOptions* options,
+                            device::mojom::blink::NFC::WatchCallback callback) {
   DCHECK(reader);
-  if (readers_.Contains(reader))
-    return;
+  DCHECK(!readers_.Contains(reader));
 
   EnsureMojoConnection();
   nfc_remote_->Watch(
       device::mojom::blink::NDEFScanOptions::From(options), next_watch_id_,
       WTF::Bind(&NFCProxy::OnReaderRegistered, WrapPersistent(this),
-                WrapPersistent(reader), next_watch_id_));
+                WrapPersistent(reader), next_watch_id_, std::move(callback)));
   readers_.insert(reader, next_watch_id_);
   next_watch_id_++;
 }
@@ -119,9 +119,11 @@ void NFCProxy::OnWatch(const Vector<uint32_t>& watch_ids,
   }
 }
 
-void NFCProxy::OnReaderRegistered(NDEFReader* reader,
-                                  uint32_t watch_id,
-                                  device::mojom::blink::NDEFErrorPtr error) {
+void NFCProxy::OnReaderRegistered(
+    NDEFReader* reader,
+    uint32_t watch_id,
+    device::mojom::blink::NFC::WatchCallback callback,
+    device::mojom::blink::NDEFErrorPtr error) {
   DCHECK(reader);
   // |reader| may have already stopped reading.
   if (!readers_.Contains(reader))
@@ -134,13 +136,15 @@ void NFCProxy::OnReaderRegistered(NDEFReader* reader,
     return;
 
   if (error) {
-    reader->OnError(error->error_type);
     readers_.erase(reader);
+    std::move(callback).Run(std::move(error));
     return;
   }
 
-  // It's good the watch request has been accepted, we do nothing here but just
-  // wait for message notifications in OnWatch().
+  std::move(callback).Run(nullptr);
+
+  // It's good the watch request has been accepted, next we just wait for
+  // message notifications in OnWatch().
 }
 
 void NFCProxy::PageVisibilityChanged() {
@@ -182,9 +186,7 @@ void NFCProxy::OnMojoConnectionError() {
   // Notify all active readers about the connection error and clear the list.
   ReaderMap readers = std::move(readers_);
   for (auto& pair : readers) {
-    // The reader may call StopReading() to remove itself from |readers_| when
-    // handling the error.
-    pair.key->OnError(device::mojom::blink::NDEFErrorType::NOT_SUPPORTED);
+    pair.key->OnMojoConnectionError();
   }
 
   // Each connection maintains its own watch ID numbering, so reset to 1 on

third_party/blink/renderer/modules/nfc/nfc_proxy.h

@@ -45,7 +45,9 @@ class MODULES_EXPORT NFCProxy final : public GarbageCollected<NFCProxy>,
   // collected.
   void AddWriter(NDEFWriter*);
 
-  void StartReading(NDEFReader*, const NDEFScanOptions*);
+  void StartReading(NDEFReader*,
+                    const NDEFScanOptions*,
+                    device::mojom::blink::NFC::WatchCallback);
   void StopReading(NDEFReader*);
   bool IsReading(const NDEFReader*);
   void Push(device::mojom::blink::NDEFMessagePtr,
@@ -61,6 +63,7 @@ class MODULES_EXPORT NFCProxy final : public GarbageCollected<NFCProxy>,
 
   void OnReaderRegistered(NDEFReader*,
                           uint32_t watch_id,
+                          device::mojom::blink::NFC::WatchCallback,
                           device::mojom::blink::NDEFErrorPtr);
 
   // Implementation of PageVisibilityObserver.

third_party/blink/renderer/modules/nfc/nfc_proxy_test.cc

@@ -53,7 +53,6 @@ class MockNDEFReader : public NDEFReader {
   MOCK_METHOD2(OnReading,
                void(const String& serial_number,
                     const device::mojom::blink::NDEFMessage& message));
-  MOCK_METHOD1(OnError, void(device::mojom::blink::NDEFErrorType error));
 };
 
 class FakeNfcService : public device::mojom::blink::NFC {
@@ -96,6 +95,10 @@ class FakeNfcService : public device::mojom::blink::NFC {
     tag_message_ = std::move(message);
   }
 
+  void set_watch_error(device::mojom::blink::NDEFErrorPtr error) {
+    watch_error_ = std::move(error);
+  }
+
   WTF::Vector<uint32_t> GetWatches() {
     WTF::Vector<uint32_t> ids;
     for (auto& pair : watches_) {
@@ -123,6 +126,10 @@ class FakeNfcService : public device::mojom::blink::NFC {
   void Watch(device::mojom::blink::NDEFScanOptionsPtr options,
              uint32_t id,
              WatchCallback callback) override {
+    if (watch_error_) {
+      std::move(callback).Run(watch_error_.Clone());
+      return;
+    }
     watches_.emplace(id, std::move(options));
     std::move(callback).Run(nullptr);
   }
@@ -141,6 +148,7 @@ class FakeNfcService : public device::mojom::blink::NFC {
   void SuspendNFCOperations() override {}
   void ResumeNFCOperations() override {}
 
+  device::mojom::blink::NDEFErrorPtr watch_error_;
   device::mojom::blink::NDEFMessagePtr tag_message_;
   mojo::Remote<device::mojom::blink::NFCClient> client_;
   std::map<uint32_t, device::mojom::blink::NDEFScanOptionsPtr> watches_;
@@ -167,8 +175,6 @@ class NFCProxyTest : public PageTestBase {
 
   FakeNfcService* nfc_service() { return nfc_service_.get(); }
 
-  void DestroyNfcService() { nfc_service_.reset(); }
-
  private:
   std::unique_ptr<FakeNfcService> nfc_service_;
 };
@@ -180,10 +186,18 @@ TEST_F(NFCProxyTest, SuccessfulPath) {
   scan_options->setURL(kTestUrl);
   auto* reader = MakeGarbageCollected<MockNDEFReader>(&document);
 
-  nfc_proxy->StartReading(reader, scan_options);
-  EXPECT_TRUE(nfc_proxy->IsReading(reader));
-  test::RunPendingTasks();
-  EXPECT_EQ(nfc_service()->GetWatches().size(), 1u);
+  {
+    base::RunLoop loop;
+    nfc_proxy->StartReading(reader, scan_options,
+                            base::BindLambdaForTesting(
+                                [&](device::mojom::blink::NDEFErrorPtr error) {
+                                  EXPECT_TRUE(error.is_null());
+                                  loop.Quit();
+                                }));
+    EXPECT_TRUE(nfc_proxy->IsReading(reader));
+    loop.Run();
+    EXPECT_EQ(nfc_service()->GetWatches().size(), 1u);
+  }
 
   // Construct a NDEFMessagePtr
   auto message = device::mojom::blink::NDEFMessage::New();
@@ -191,24 +205,26 @@ TEST_F(NFCProxyTest, SuccessfulPath) {
   auto record = device::mojom::blink::NDEFRecord::New();
   WTF::Vector<uint8_t> record_data(
       {0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10});
-  record->record_type = "opaque";
+  record->record_type = "mime";
   record->data = WTF::Vector<uint8_t>(record_data);
   message->data.push_back(std::move(record));
 
-  base::RunLoop loop;
-  EXPECT_CALL(*reader, OnReading(String(kFakeNfcTagSerialNumber),
-                                 MessageEquals(record_data)))
-      .WillOnce(Invoke([&](const String& serial_number,
-                           const device::mojom::blink::NDEFMessage& message) {
-        loop.Quit();
-      }));
-
-  nfc_proxy->Push(
-      std::move(message), /*options=*/nullptr,
-      base::BindLambdaForTesting([&](device::mojom::blink::NDEFErrorPtr error) {
-        nfc_service()->TriggerWatchEvent();
-      }));
-  loop.Run();
+  {
+    base::RunLoop loop;
+    EXPECT_CALL(*reader, OnReading(String(kFakeNfcTagSerialNumber),
+                                   MessageEquals(record_data)))
+        .WillOnce(Invoke([&](const String& serial_number,
+                             const device::mojom::blink::NDEFMessage& message) {
+          loop.Quit();
+        }));
+
+    nfc_proxy->Push(std::move(message), /*options=*/nullptr,
+                    base::BindLambdaForTesting(
+                        [&](device::mojom::blink::NDEFErrorPtr error) {
+                          nfc_service()->TriggerWatchEvent();
+                        }));
+    loop.Run();
+  }
 
   nfc_proxy->StopReading(reader);
   EXPECT_FALSE(nfc_proxy->IsReading(reader));
@@ -223,16 +239,23 @@ TEST_F(NFCProxyTest, ErrorPath) {
   scan_options->setURL(kTestUrl);
   auto* reader = MakeGarbageCollected<MockNDEFReader>(&document);
 
-  nfc_proxy->StartReading(reader, scan_options);
-  EXPECT_TRUE(nfc_proxy->IsReading(reader));
-  test::RunPendingTasks();
-
+  // Make the fake NFC service return an error for the incoming watch request.
+  nfc_service()->set_watch_error(device::mojom::blink::NDEFError::New(
+      device::mojom::blink::NDEFErrorType::NOT_READABLE));
   base::RunLoop loop;
-  EXPECT_CALL(*reader, OnError(_))
-      .WillOnce(
-          Invoke([&](device::mojom::blink::NDEFErrorType) { loop.Quit(); }));
-  DestroyNfcService();
+  nfc_proxy->StartReading(
+      reader, scan_options,
+      base::BindLambdaForTesting([&](device::mojom::blink::NDEFErrorPtr error) {
+        // We got the error prepared before.
+        EXPECT_FALSE(error.is_null());
+        EXPECT_EQ(error->error_type,
+                  device::mojom::blink::NDEFErrorType::NOT_READABLE);
+        loop.Quit();
+      }));
+  EXPECT_TRUE(nfc_proxy->IsReading(reader));
   loop.Run();
+
+  EXPECT_EQ(nfc_service()->GetWatches().size(), 0u);
   EXPECT_FALSE(nfc_proxy->IsReading(reader));
 }
 

third_party/blink/web_tests/external/wpt/web-nfc/NDEFReader-document-hidden-manual.https.html

@@ -9,15 +9,13 @@
 
 promise_test(async t => {
   const reader = new NDEFReader();
-  reader.scan();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  return await new Promise((resolve, reject) => {
-    readerWatcher.wait_for("reading").then(event => {
-      if (document.hidden) reject();
-      resolve();
-    });
+  const promise = readerWatcher.wait_for("reading").then(event => {
+    if (document.hidden) reject();
+    resolve();
   });
+  await reader.scan();
+  await promise;
 }, "Test NDEFReader.onreading is not fired when document is hidden");
 
 </script>

third_party/blink/web_tests/external/wpt/web-nfc/NDEFReader_scan.https.html

@@ -22,59 +22,56 @@ const invalid_signals = [
 
 function waitSyntaxErrorPromise(t, scan_options) {
   const reader = new NDEFReader();
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  const promise = readerWatcher.wait_for("error").then(event => {
-    assert_equals(event.error.name, 'SyntaxError');
-  });
-  // NDEFReader#scan() asynchronously dispatches the syntax error event.
-  reader.scan(scan_options);
-  return promise;
+  return promise_rejects(t, 'SyntaxError', reader.scan(scan_options));
 }
 
+promise_test(async t => {
+  const reader = new NDEFReader();
+  const promises = [];
+  invalid_signals.forEach(invalid_signal => {
+    promises.push(promise_rejects(t, new TypeError(),
+        reader.scan({ signal: invalid_signal })));
+  });
+  await Promise.all(promises);
+}, "Test that NDEFReader.scan rejects if signal is not an AbortSignal.");
+
 promise_test(async t => {
   await waitSyntaxErrorPromise(t, {url: "www.a.com"});
-}, "Test that NDEFReader.scan fails if NDEFScanOptions.url is missing \
+}, "Test that NDEFReader.scan rejects if NDEFScanOptions.url is missing \
 components.");
 
 promise_test(async t => {
   await waitSyntaxErrorPromise(t, {url: "invalid"});
-}, "Test that NDEFReader.scan fails if NDEFScanOptions.url is invalid.");
+}, "Test that NDEFReader.scan rejects if NDEFScanOptions.url is invalid.");
 
 promise_test(async t => {
   await waitSyntaxErrorPromise(t, {url: "http://a.com"});
-}, "Test that NDEFReader.scan fails if NDEFScanOptions.url has wrong \
+}, "Test that NDEFReader.scan rejects if NDEFScanOptions.url has wrong \
 protocol.");
 
 nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  reader.scan();
   mockNFC.setHWStatus(NFCHWStatus.DISABLED);
-  const event = await readerWatcher.wait_for("error");
-  assert_equals(event.error.name, 'NotReadableError');
+  const reader = new NDEFReader();
+  await promise_rejects(t, 'NotReadableError', reader.scan());
 }, "NDEFReader.scan should fail if NFC HW is disabled.");
 
 nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  reader.scan();
   mockNFC.setHWStatus(NFCHWStatus.NOT_SUPPORTED);
-  const event = await readerWatcher.wait_for("error");
-  assert_equals(event.error.name, 'NotSupportedError');
+  const reader = new NDEFReader();
+  await promise_rejects(t, 'NotSupportedError', reader.scan());
 }, "NDEFReader.scan should fail if NFC HW is not supported.");
 
 nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal});
+  await reader.scan({signal : controller.signal});
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await promise;
 }, "Test that nfc watch success if NFC HW is enabled.");
 
@@ -82,14 +79,13 @@ nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal, url: "https://a.com"});
+  await reader.scan({signal : controller.signal, url: "https://a.com"});
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await promise;
 }, "Test that NDEFReader.scan succeeds if NDEFScanOptions.url is valid URL.");
 
@@ -97,14 +93,13 @@ nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal, url: "https://a.com/*"});
+  await reader.scan({signal : controller.signal, url: "https://a.com/*"});
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await promise;
 }, "Test that NDEFReader.scan succeeds if NDEFScanOptions.url is valid URL \
 with '*' wildcard character in path.");
@@ -113,14 +108,13 @@ nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal, url: "https://a.com/*/bar"});
+  await reader.scan({signal : controller.signal, url: "https://a.com/*/bar"});
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await promise;
 }, "Test that NDEFReader.scan succeeds if NDEFScanOptions.url is valid URL \
 with '*' wildcard character in the beginning of path component followed by \
@@ -130,102 +124,90 @@ nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal, url: ""});
+  await reader.scan({signal : controller.signal, url: ""});
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await promise;
 }, "Test that NDEFReader.scan succeeds if NDEFScanOptions.url is empty.");
 
 nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
-
   const controller = new AbortController();
   controller.abort();
-  reader.scan({signal: controller.signal});
-
-  await new Promise((resolve, reject) => {
-    readerWatcher.wait_for("reading").then(event => {
-      reject("reading event should not be fired.");
-    });
-    t.step_timeout(resolve, 100);
-  });
+  await promise_rejects(t, 'AbortError', reader.scan({signal: controller.signal}));
+}, "Test that NDEFReader.scan rejects if NDEFScanOptions.signal is already aborted.");
 
-}, "Test that NDEFReader.onreading should not be fired if NDEFScanOptions.signal \
-is aborted.");
+nfc_test(async (t, mockNFC) => {
+  const reader = new NDEFReader();
+  const controller = new AbortController();
+  const promise = reader.scan({signal: controller.signal});
+  controller.abort();
+  await promise_rejects(t, 'AbortError', promise);
+}, "Test that NDEFReader.scan rejects if NDEFScanOptions.signal aborts right after \
+the scan invocation.");
 
 nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
   const message = createMessage([createTextRecord(test_text_data)]);
+  const promise = readerWatcher.wait_for("reading").then(event => {
+    assert_true(event instanceof NDEFReadingEvent);
+  });
+  await reader.scan({signal : controller.signal});
 
   mockNFC.setReadingMessage(message);
+  await promise;
 
-  reader.scan({signal: controller.signal});
-  const event = await readerWatcher.wait_for("reading");
-  assert_true(event instanceof NDEFReadingEvent);
+  reader.onreading = t.unreached_func("reading event should not be fired.");
   mockNFC.setReadingMessage(message);
   controller.abort();
-
   await new Promise((resolve, reject) => {
-    readerWatcher.wait_for("reading").then(event => {
-      reject("reading event should not be fired.");
-    });
     t.step_timeout(resolve, 100);
   });
-
-}, "Synchronously signaled abort.");
+}, "Test that NDEFReader can not get any reading events once the signal aborts.");
 
 nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
+  const promise = readerWatcher.wait_for("reading").then(event => {
+    controller.abort();
+    assert_true(event instanceof NDEFReadingEvent);
+    // The message contains only an external type record.
+    assert_equals(event.message.records.length, 1);
+    assert_equals(event.message.records[0].recordType, 'example.com:payloadIsMessage', 'recordType');
+    // The external type record's payload is a message, which contains only a text record.
+    const embeddedRecords = event.message.records[0].toRecords();
+    assert_equals(embeddedRecords.length, 1);
+    assert_equals(embeddedRecords[0].recordType, 'text', 'recordType');
+    assert_equals(embeddedRecords[0].mediaType, null, 'mediaType');
+    const decoder = new TextDecoder();
+    assert_equals(decoder.decode(embeddedRecords[0].data), test_text_data,
+                    'data has the same content with the original dictionary');
+  });
+  await reader.scan({signal : controller.signal});
 
   const payloadMessage = createMessage([createTextRecord(test_text_data)]);
   const message = createMessage([createRecord('example.com:payloadIsMessage',
           payloadMessage)]);
   mockNFC.setReadingMessage(message);
-
-  reader.scan({signal : controller.signal});
-  const event = await readerWatcher.wait_for("reading");
-  controller.abort();
-  assert_true(event instanceof NDEFReadingEvent);
-  // The message contains only an external type record.
-  assert_equals(event.message.records.length, 1);
-  assert_equals(event.message.records[0].recordType, 'example.com:payloadIsMessage', 'recordType');
-  // The external type record's payload is a message, which contains only a text record.
-  const embeddedRecords = event.message.records[0].toRecords();
-  assert_equals(embeddedRecords.length, 1);
-  assert_equals(embeddedRecords[0].recordType, 'text', 'recordType');
-  assert_equals(embeddedRecords[0].mediaType, null, 'mediaType');
-  const decoder = new TextDecoder();
-  assert_equals(decoder.decode(embeddedRecords[0].data), test_text_data,
-                  'data has the same content with the original dictionary');
+  await promise;
 }, "NDEFRecord.toRecords returns its embedded records correctly.");
 
-test(() => {
-  const reader = new NDEFReader();
-  invalid_signals.forEach(invalid_signal => {
-    assert_throws(new TypeError(),
-        () => { reader.scan({ signal: invalid_signal }); });
-  });
-}, "NDEFReader.scan should fail if signal is not an AbortSignal.");
-
 nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
   mockNFC.setIsNDEFTech(false);
-  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
 
+  const reader = new NDEFReader();
+  reader.onreading = t.unreached_func("reading event should not be fired.");
+  await reader.scan();
+
+  mockNFC.setReadingMessage(createMessage([createTextRecord(test_text_data)]));
   await new Promise((resolve, reject) => {
-    reader.onreading = () => reject("reading event should not be fired.");
-    reader.scan();
     t.step_timeout(resolve, 100);
   });
 }, "Test that NDEFReader.onreading should not be fired if the NFC tag does not \
@@ -234,16 +216,15 @@ expose NDEF technology.");
 nfc_test(async (t, mockNFC) => {
   const reader = new NDEFReader();
   const controller = new AbortController();
-  mockNFC.setReadingMessage({ records: [] });
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
   const promise = readerWatcher.wait_for("reading").then(event => {
     assert_equals(event.serialNumber, fake_tag_serial_number);
     assert_equals(event.message.records.length, 0);
     controller.abort();
   });
-  // NDEFReader#scan() asynchronously dispatches the reading event.
-  reader.scan({signal : controller.signal});
+  await reader.scan({signal : controller.signal});
+
+  mockNFC.setReadingMessage({ records: [] });
   await promise;
 }, "Test that NDEFReader.onreading should be fired on an unformatted NFC tag \
 with empty records array for NDEFMessage.");

third_party/blink/web_tests/external/wpt/web-nfc/NDEFReader_scan_iframe.https.html

@@ -17,7 +17,7 @@ nfc_test(async (t, mockNFC) => {
     assert_true(event instanceof NDEFReadingEvent);
     controller.abort();
   });
-  reader.scan({ signal: controller.signal });
+  await reader.scan({ signal: controller.signal });
 
   const iframe = document.createElement('iframe');
   iframe.src = 'resources/support-iframe.html';
@@ -40,4 +40,4 @@ nfc_test(async (t, mockNFC) => {
 }, 'Test that NDEFWriter.scan is not suspended if iframe gains focus.');
 
 </script>
-</body>
\ No newline at end of file
+</body>

third_party/blink/web_tests/external/wpt/web-nfc/NDEFWriter_push.https.html

@@ -316,18 +316,18 @@ nfc_test(async (t, mockNFC) => {
   const message = createMessage([createTextRecord(test_text_data)]);
   const controller = new AbortController();
   const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  const promise = readerWatcher.wait_for("reading").then(event => {
-    controller.abort();
-    assertWebNDEFMessagesEqual(event.message, new NDEFMessage(message));
-  });
-
-  reader.scan({ signal: controller.signal });
+  await reader.scan({ signal: controller.signal });
 
   const writer = new NDEFWriter();
   await writer.push(test_text_data, { ignoreRead: false });
-  mockNFC.setReadingMessage(message);
   assertNDEFMessagesEqual(test_text_data, mockNFC.pushedMessage());
-  await promise;
+
+  mockNFC.setReadingMessage(message);
+  await readerWatcher.wait_for("reading").then(event => {
+    controller.abort();
+    assertWebNDEFMessagesEqual(event.message, new NDEFMessage(message));
+  });
+
 }, "NDEFWriter.push should read data when ignoreRead is false.");
 
 nfc_test(async (t, mockNFC) => {
@@ -335,7 +335,7 @@ nfc_test(async (t, mockNFC) => {
   const message = createMessage([createTextRecord(test_text_data)]);
   // Ignore reading if NDEFPushOptions.ignoreRead is true
   reader.onreading = t.unreached_func("reading event should not be fired.");
-  reader.scan();
+  await reader.scan();
 
   const writer = new NDEFWriter();
   await writer.push(test_text_data, { ignoreRead: true });

third_party/blink/web_tests/external/wpt/web-nfc/idlharness.https.window-expected.txt

 This is a testharness.js-based test.
-Found 72 tests; 70 PASS, 2 FAIL, 0 TIMEOUT, 0 NOTRUN.
+Found 72 tests; 71 PASS, 1 FAIL, 0 TIMEOUT, 0 NOTRUN.
 PASS idl_test setup
 PASS idl_test validation
 PASS NDEFMessage interface: existence and properties of interface object
@@ -53,7 +53,7 @@ PASS NDEFReader interface: existence and properties of interface prototype objec
 PASS NDEFReader interface: existence and properties of interface prototype object's @@unscopables property
 PASS NDEFReader interface: attribute onerror
 PASS NDEFReader interface: attribute onreading
-FAIL NDEFReader interface: operation scan(NDEFScanOptions) assert_unreached: Throws "TypeError: Illegal invocation" instead of rejecting promise Reached unreachable code
+PASS NDEFReader interface: operation scan(NDEFScanOptions)
 PASS NDEFReader must be primary interface of new NDEFReader();
 PASS Stringification of new NDEFReader();
 PASS NDEFReader interface: new NDEFReader(); must inherit property "onerror" with the proper type

third_party/blink/web_tests/external/wpt/web-nfc/resources/nfc-helpers.js

@@ -174,22 +174,20 @@ function testNDEFScanOptions(message, scanOptions, unmatchedScanOptions, desc) {
     const reader2 = new NDEFReader();
     const controller = new AbortController();
 
-    mockNFC.setReadingMessage(message);
-
     // Reading from unmatched reader will not be triggered
     reader1.onreading = t.unreached_func("reading event should not be fired.");
     unmatchedScanOptions.signal = controller.signal;
-    reader1.scan(unmatchedScanOptions);
+    await reader1.scan(unmatchedScanOptions);
 
     const readerWatcher = new EventWatcher(t, reader2, ["reading", "error"]);
-
     const promise = readerWatcher.wait_for("reading").then(event => {
       controller.abort();
       assertWebNDEFMessagesEqual(event.message, new NDEFMessage(message));
     });
-    // NDEFReader#scan() asynchronously dispatches the onreading event.
     scanOptions.signal = controller.signal;
-    reader2.scan(scanOptions);
+    await reader2.scan(scanOptions);
+
+    mockNFC.setReadingMessage(message);
     await promise;
   }, desc);
 }
@@ -200,19 +198,16 @@ function testReadingMultiMessages(
     const reader = new NDEFReader();
     const controller = new AbortController();
     const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-
     const promise = readerWatcher.wait_for("reading").then(event => {
       controller.abort();
       assertWebNDEFMessagesEqual(event.message, new NDEFMessage(message));
     });
-    // NDEFReader#scan() asynchronously dispatches the onreading event.
     scanOptions.signal = controller.signal;
-    reader.scan(scanOptions);
+    await reader.scan(scanOptions);
 
     // Unmatched message will not be read
     mockNFC.setReadingMessage(unmatchedMessage);
     mockNFC.setReadingMessage(message);
-
     await promise;
   }, desc);
 }