bluetooth: Introduce helper function for requesting a disconnection

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

Index: third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js
diff --git a/third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js b/third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js
index fd9719a503127e16868524ab3d36bc68be4464de..25cd7911ae71e0cd5361909ffb104661d0179ba3 100644
--- a/third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js
+++ b/third_party/WebKit/LayoutTests/resources/bluetooth/bluetooth-helpers.js
@@ -318,6 +318,18 @@ class EventCatcher {
   }
 }
 
+// Returns a function that when called returns a promise that resolves when

[scheib, 2016/10/25 04:28:05]

Returns via a promise a function 'request_disconnection()',
which via a promise resolves when the device has disconnected.
Use by:
  device.gatt.connect()
  .then(gattServer => get_request_disconnection(gattServer))
  .then(requestDisconnection => requestDisconnection())
  .then(() => // device has disconnected ...

[ortuno, 2016/10/26 04:03:22]

Done.

+// the device has 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 }]