Implement WebBluetooth getDescriptor[s]

third_party/WebKit/LayoutTests/bluetooth/script-tests/gatt-op-reconnect-during-error.js

 promise_test(() => {
   let val = new Uint8Array([1]);
   return setBluetoothFakeAdapter('GATTOperationFailsAfterReconnectionAdapter')
     .then(() => requestDeviceWithKeyDown({
       filters: [{services: ['health_thermometer']}]}))
     .then(device => device.gatt.connect())
     .then(gatt => gatt.getPrimaryService('health_thermometer'))
     .then(service => service.getCharacteristic('measurement_interval'))
     .then(characteristic => {
       let promise = assert_promise_rejects_with_message(
         characteristic.CALLS([
-          readValue()| writeValue(val)| startNotifications()]),
+          readValue()|

[ortuno, 2016/12/02 06:14:50]

nit: unrelated to the CL.

[dougt, 2016/12/02 18:31:28]

Acknowledged.

+          writeValue(val)|
+          startNotifications()]),
         new DOMException('GATT Server disconnected while performing a GATT operation.',
                          'NetworkError'));
       let gatt = characteristic.service.device.gatt;
       gatt.disconnect();
       return gatt.connect().then(() => promise);
     });
 }, 'disconnect() and connect() called during a FUNCTION_NAME call that ' +
    'fails. Reject with NetworkError.');