Fix WebBluetooth generator to distinguish between different methods.

third_party/WebKit/LayoutTests/bluetooth/script-tests/service-garbage-collection-ran-during-error.js

-'use strict';
-promise_test(() => {
-  let promise;
-  return setBluetoothFakeAdapter('MissingServiceHeartRateAdapter')
-    .then(() => requestDeviceWithKeyDown({
-      filters: [{services: ['heart_rate']}]}))
-    .then(device => device.gatt.connect())
-    .then(gattServer => {
-      promise = assert_promise_rejects_with_message(
-        gattServer.CALLS([
-          getPrimaryService('heart_rate')|
-          getPrimaryServices()|
-          getPrimaryServices('heart_rate')[UUID]]),
-        new DOMException(
-          'GATT Server disconnected while retrieving services.',
-          'NetworkError'));
-      // Disconnect called to clear attributeInstanceMap and allow the
-      // object to get garbage collected.
-      gattServer.disconnect();
-    })
-    .then(runGarbageCollection)
-    .then(() => promise);
-}, 'Garbage Collection ran during a FUNCTION_NAME call that failed. ' +
-   'Should not crash.');