Implement WebBluetooth descriptor.readValue()

third_party/WebKit/LayoutTests/bluetooth/script-tests/descriptor/io-op-device-reconnects-during-error.js

+promise_test(
+    () => {
+      let val = new Uint8Array([1]);
+      return setBluetoothFakeAdapter(
+                 'DisconnectingDuringFailureGATTOperationAdapter')
+          .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 => characteristic.getDescriptor(
+                  'gatt.characteristic_user_description'))
+          .then(descriptor => {
+            let disconnected = eventPromise(
+                descriptor.characteristic.service.device,
+                'gattserverdisconnected');
+            let promise = assert_promise_rejects_with_message(
+                descriptor.CALLS([readValue()]),
+                new DOMException(
+                    'GATT Server disconnected while performing a GATT operation.',
+                    'NetworkError'));
+            return disconnected
+                .then(
+                    () =>
+                        descriptor.characteristic.service.device.gatt.connect())
+                .then(() => promise);

[ortuno, 2017/01/20 04:30:53]

I don't think you need "() =>"

[dougt, 2017/01/23 21:40:36]

Acknowledged.

+          });
+    },
+    'Device reconnects during a FUNCTION_NAME call that fails. Reject ' +
+        'with NetworkError.');