Implement WebBluetooth descriptor.readValue()

third_party/WebKit/LayoutTests/bluetooth/script-tests/descriptor/io-op-disconnect-called-before.js

+'use strict';
+promise_test(() => {
+  let val = new Uint8Array([1]);
+  return setBluetoothFakeAdapter('DisconnectingHealthThermometerAdapter')
+    .then(() => requestDeviceWithKeyDown({
+      filters: [{services: ['health_thermometer']}]}))
+    .then(device => device.gatt.connect())
+    .then(gattServer => {
+      return gattServer.getPrimaryService('health_thermometer')
+        .then(service => service.getCharacteristic('measurement_interval'))
+        .then(characteristic => characteristic.getDescriptor('gatt.characteristic_user_description'))
+        .then(descriptor => {
+          gattServer.disconnect();
+          return assert_promise_rejects_with_message(
+            descriptor.CALLS([
+              readValue()
+              ]),
+            new DOMException(
+              'GATT Server is disconnected. Cannot perform GATT operations.',
+              'NetworkError'));
+        });
+    });
+}, 'disconnect() called before FUNCTION_NAME. Reject with NetworkError.');