Implement WebBluetooth descriptor.readValue()

third_party/WebKit/LayoutTests/bluetooth/script-tests/descriptor/io-op-device-disconnects-before.js

+'use strict';
+promise_test(() => {
+  let val = new Uint8Array([1]);
+  return setBluetoothFakeAdapter('DisconnectingHealthThermometerAdapter')
+      .then(() => requestDeviceWithKeyDown({

[ortuno, 2017/01/20 04:30:52]

nit: align with 't'.

[dougt, 2017/01/23 21:40:36]

Acknowledged.

+              filters: [{services: ['health_thermometer']}],
+              optionalServices: [request_disconnection_service_uuid]
+            }))
+      .then(device => device.gatt.connect())
+      .then(gattServer => {
+        let measurement_interval;

[ortuno, 2017/01/20 04:30:52]

I think you meant user_description here.  Otherwise you are replacing
'user_description' in bluetooth_helpers.js.

[dougt, 2017/01/23 21:40:36]

Done.

+        return gattServer.getPrimaryService('health_thermometer')
+            .then(ht => ht.getCharacteristic('measurement_interval'))
+            .then(
+                characteristic => characteristic.getDescriptor(
+                    'gatt.characteristic_user_description'))
+            .then(d => user_description = d)
+            .then(() => get_request_disconnection(gattServer))
+            .then(requestDisconnection => requestDisconnection())
+            .then(
+                () => assert_promise_rejects_with_message(
+                    user_description.CALLS([readValue()]),
+                    new DOMException(
+                        'GATT Server is disconnected. Cannot perform GATT operations.',
+                        'NetworkError')));
+      });
+}, 'Device disconnects before FUNCTION_NAME. Reject with NetworkError.');