Fix WebBluetooth generator to distinguish between different methods.

third_party/WebKit/LayoutTests/bluetooth/script-tests/server/disconnect-invalidates-objects.js

 'use strict';
 promise_test(() => {
   let promise;
   return setBluetoothFakeAdapter('TwoHeartRateServicesAdapter')
     .then(() => requestDeviceWithKeyDown({
       filters: [{services: ['heart_rate']}]}))
     .then(device => device.gatt.connect())
     .then(gattServer => {
       return gattServer
         .CALLS([
@@ skipping 25 matching lines @@
             error));
         promises = promises.then(() =>
           assert_promise_rejects_with_message(
             service.getCharacteristics('body_sensor_location'),
             error));
       }
       return promises;
     });
 }, 'Calls on services after we disconnect and connect again. '+
    'Should reject with InvalidStateError.');