Fix WebBluetooth generator to distinguish between different methods.

third_party/WebKit/LayoutTests/bluetooth/script-tests/gatt-op-device-reconnects-during-success.js

-promise_test(() => {
-  let val = new Uint8Array([1]);
-  return setBluetoothFakeAdapter('DisconnectingDuringSuccessGATTOperationAdapter')
-    .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 disconnected = eventPromise(characteristic.service.device, 'gattserverdisconnected');
-      let promise = assert_promise_rejects_with_message(
-        characteristic.CALLS([
-          readValue()|
-          writeValue(val)|
-          startNotifications()]),
-        new DOMException('GATT Server disconnected while performing a GATT operation.',
-                         'NetworkError'));
-      return disconnected.then(() => characteristic.service.device.gatt.connect())
-                         .then(() => promise);
-    });
-}, 'Device reconnects during a FUNCTION_NAME call that succeeds. Reject ' +
-   'with NetworkError.');