[webnfc] Do not support multiple scans on the same reader.

We added support for multiple scan invocations on the same Reader in
this CL https://chromium-review.googlesource.com/c/chromium/src/+/2145263

Since Origin Trials feedback was to remove Filtering,
spec : w3c/web-nfc#565
WIP CL : https://chromium-review.googlesource.com/c/chromium/src/+/2225770/
we tried to reason if in a world without filtering, multiple scans on
the same Reader is needed at all. The present thinking is to simply
reject scan promise when there's already an ongoing scan.

Spec discussions: w3c/web-nfc#592

Bug: 520391
Change-Id: Ic50873ddc30351cec6656ac7b030394dc9fa18ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2297559
Commit-Queue: Rijubrata Bhaumik <rijubrata.bhaumik@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790438}

web-nfc/NDEFReader_scan.https.html

@@ -284,4 +284,19 @@
   await promise;
 }, "Test that reading message with multiple records should succeed.");
 
+nfc_test(async (t, mockNFC) => {
+  const reader = new NDEFReader();
+  const promise1 = reader.scan();
+  const promise2 = promise_rejects_dom(t, 'InvalidStateError', reader.scan());
+  await promise1;
+  await promise2;
+}, "Test that NDEFReader.scan rejects if there is already an ongoing scan.");
+
+nfc_test(async (t, mockNFC) => {
+  const reader = new NDEFReader();
+  const controller = new AbortController();
+  await reader.scan({signal : controller.signal});
+  controller.abort();
+  await reader.scan();
+}, "Test that NDEFReader.scan can be started after the previous scan is aborted.");
 </script>

web-nfc/NDEFReader_scan_filter.https.html

@@ -162,79 +162,4 @@
   );
 }
 
-nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
-  const controller = new AbortController();
-  const signal = controller.signal;
-  const textMsg = createMessage([createTextRecord(test_text_data)]);
-  const urlMsg = createMessage([createUrlRecord(test_url_data)]);
-  const mimeMsg = createMessage([createMimeRecord(test_buffer_data)]);
-
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  const promise = readerWatcher.wait_for("reading").then(event => {
-    controller.abort();
-    assertWebNDEFMessagesEqual(event.message, new NDEFMessage(mimeMsg));
-  });
-
-  const scanOptions1 = {recordType: "text", signal: signal};
-  const scanOptions2 = {recordType: "url", signal: signal};
-  const scanOptions3 = {recordType: "mime", signal: signal};
-
-  await reader.scan(scanOptions1);
-  await reader.scan(scanOptions2);
-  // There is maximum one filter for an NDEFReader object,
-  // last filter will replace all previous ones.
-  await reader.scan(scanOptions3);
-
-  mockNFC.setReadingMessage(textMsg);
-  mockNFC.setReadingMessage(urlMsg);
-  mockNFC.setReadingMessage(mimeMsg);
-  await promise;
-}, "Multiple scan() from the same NDEFReader object with new options should \
-replace existing filters.");
-
-nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
-  const controller1 = new AbortController();
-  const controller2 = new AbortController();
-  const urlMsg = createMessage([createUrlRecord(test_url_data)]);
-  const mimeMsg = createMessage([createMimeRecord(test_buffer_data)]);
-
-  const readerWatcher = new EventWatcher(t, reader, ["reading", "error"]);
-  const promise = readerWatcher.wait_for("reading").then(event => {
-    assertWebNDEFMessagesEqual(event.message, new NDEFMessage(mimeMsg));
-    controller2.abort();
-  });
-
-  const scanOptions1 = {recordType: "url", signal: controller1.signal};
-  const scanOptions2 = {recordType: "mime", signal: controller2.signal};
-
-  // There is maximum one filter for an NDEFReader object,
-  // last filter will replace all previous ones.
-  await reader.scan(scanOptions1);
-  await reader.scan(scanOptions2);
-
-  mockNFC.setReadingMessage(urlMsg);
-
-  controller1.abort();
-
-  mockNFC.setReadingMessage(mimeMsg);
-  await promise;
-}, "Aborting on previous signal should not stop current reading for multiple \
-scan() with different signals.");
-
-nfc_test(async (t, mockNFC) => {
-  const reader = new NDEFReader();
-  const controller = new AbortController();
-  const scanOptions1 = {recordType: "url", signal: controller.signal };
-  const scanOptions2 = {recordType: "mime"};
-
-  await reader.scan(scanOptions1);
-  const promise = reader.scan(scanOptions2);
-  controller.abort();
-
-  await promise_rejects_dom(t, 'AbortError', promise);
-}, "Aborting on previous signal can stop current reading if no new signals \
-passed to successive scan().");
-
 </script>