bluetooth: Introduce helper function for requesting a disconnection

third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js

 'use strict';
 
 // Bluetooth UUID constants:
 // Services:
 var blacklist_test_service_uuid = "611c954a-263b-4f4a-aab6-01ddb953f985";
 var request_disconnection_service_uuid = "01d7d889-7451-419f-aeb8-d65e7b9277af";
 // Characteristics:
 var blacklist_exclude_reads_characteristic_uuid =
   "bad1c9a2-9a5b-4015-8b60-1579bbbf2135";
 var request_disconnection_characteristic_uuid =
@@ skipping 300 matching lines @@
   constructor(object, event) {
     this.eventFired = false;
     let event_listener = e => {
       object.removeEventListener(event, event_listener);
       this.eventFired = true;
     }
     object.addEventListener(event, event_listener);
   }
 }
 
+// Returns a function that when called returns a promise that resolves when
+// the device has disconnected. Example:
+// device.gatt.connect()
+//   .then(gatt => get_request_disconnection(gatt))
+//   .then(requestDisconnection => requestDisconnection())
+//   .then(() => // device is now disconnected)
+function get_request_disconnection(gattServer) {
+  return gattServer.getPrimaryService(request_disconnection_service_uuid)
+    .then(service => service.getCharacteristic(request_disconnection_characteristic_uuid))
+    .then(characteristic => {
+      // TODO(crbug.com/543466): Wrap in assert_promise_rejects_with_message()
+      // once connection is required for writeValue to succeed.
+      return () => characteristic.writeValue(new Uint8Array([0]));
+    });
+}
+
 function generateRequestDeviceArgsWithServices(services = ['heart_rate']) {
   return [{
     filters: [{ services: services }]
   }, {
     filters: [{ services: services, name: 'Name' }]
   }, {
     filters: [{ services: services, namePrefix: 'Pre' }]
   }, {
     filters: [{ services: services, name: 'Name', namePrefix: 'Pre' }]
   }, {
     filters: [{ services: services }],
     optionalServices: ['heart_rate']
   }, {
     filters: [{ services: services, name: 'Name' }],
     optionalServices: ['heart_rate']
   }, {
     filters: [{ services: services, namePrefix: 'Pre' }],
     optionalServices: ['heart_rate']
   }, {
     filters: [{ services: services, name: 'Name', namePrefix: 'Pre' }],
     optionalServices: ['heart_rate']
   }];
 }