Implement WebBluetooth descriptor.readValue()

third_party/WebKit/public/platform/modules/bluetooth/web_bluetooth.mojom

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module blink.mojom;
 
 import "device/bluetooth/public/interfaces/uuid.mojom";
 
 // Bluetooth Terminology:
 //
@@ skipping 85 matching lines @@
   GATT_NOT_AUTHORIZED,
   BLOCKLISTED_DESCRIPTOR_UUID,
   BLOCKLISTED_CHARACTERISTIC_UUID,
   BLOCKLISTED_READ,
   BLOCKLISTED_WRITE,
   NOT_ALLOWED_TO_ACCESS_ANY_SERVICE,
   NOT_ALLOWED_TO_ACCESS_SERVICE,
   REQUEST_DEVICE_WITH_BLOCKLISTED_UUID,
   REQUEST_DEVICE_FROM_CROSS_ORIGIN_IFRAME,
   REQUEST_DEVICE_WITHOUT_FRAME,
+  DESCRIPTOR_NO_LONGER_EXISTS,
 };
 
 struct WebBluetoothScanFilter {
   array<bluetooth.mojom.UUID>? services;
   string? name;
   string? name_prefix;
 };
 
 struct WebBluetoothRequestDeviceOptions {
   array<WebBluetoothScanFilter>? filters;
@@ skipping 116 matching lines @@
   // If |descriptor_uuid| is present, filters descriptors by
   // |descriptor_uuid|. Otherwise returns all non-blocklisted descriptors.
   // If |quantity| == WebBluetoothGATTQueryQuantity::SINGLE, at most one
   // characteristic will be returned.
   RemoteCharacteristicGetDescriptors(
     string characteristics_instance_id,
     WebBluetoothGATTQueryQuantity quantity,
     bluetooth.mojom.UUID? descriptor_uuid) => (
       WebBluetoothResult result,
       array<WebBluetoothRemoteGATTDescriptor>? descriptors);
+
+  // Reads the value for descriptor with |descriptor_instance_id|.

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

I think you wrote this comment twice?

[dougt, 2017/01/23 21:40:37]

Done.

+  // If the value is successfully read the callback will be run with
+  // WebBluetoothResult::SUCCESS and the descriptor's value. If the value is not
+  // successfully read the callback with be run with the corresponding error and
+  // nullptr for value.
+
+  // Reads the value for the descriptor identified by
+  // |descriptor_instance_id|. If the value is successfully read the callback
+  // will be run with WebBluetoothResult::SUCCESS and the descriptor's value. If
+  // the value is not successfully read the callback with be run with the
+  // corresponding error and nullptr for value

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

nit: Shouldn't this be nullopt.

[dougt, 2017/01/23 21:40:37]

Not sure.  On the C++ binding side, the callback is going to be called with an
Optional<Vector<uint8_t>>. I think when its not set (and when the result !=
SUCCESS), the value is testable with is_null.  Vince, do you know the answer
here since you just updated these docs?

+  RemoteDescriptorReadValue(
+    string descriptor_instance_id) => (
+    WebBluetoothResult result,
+    array<uint8>? value);
 };
 
 // Classes should implement this interface and pass an associated pointer
 // bound to them to the WebBluetoothService by using SetClient. Classes
 // that do this will be notified of device events e.g. device disconnection.
 interface WebBluetoothServiceClient {
   // The characteristic identified by |characteristic_instance_id| has received
   // a notification of value change.
   RemoteCharacteristicValueChanged(string characteristic_instance_id,
                                    array<uint8> value);
 
   // The device identified by |device_id| has been disconnected.
   GattServerDisconnected(WebBluetoothDeviceId device_id);
 };