Implement WebBluetooth getDescriptor[s]

device/bluetooth/bluetooth_device.h

Index: device/bluetooth/bluetooth_device.h
diff --git a/device/bluetooth/bluetooth_device.h b/device/bluetooth/bluetooth_device.h
index 135aad616ae2e62398433d46ddcb2731be62673e..26cf85ca2b7dfb6d54136353e4742beb276aee67 100644
--- a/device/bluetooth/bluetooth_device.h
+++ b/device/bluetooth/bluetooth_device.h
@@ -32,6 +32,7 @@ namespace device {
 class BluetoothAdapter;
 class BluetoothGattConnection;
 class BluetoothRemoteGattCharacteristic;
+class BluetoothRemoteGattDescriptor;
 class BluetoothSocket;
 class BluetoothUUID;
 
@@ -565,6 +566,10 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothDevice {
       const std::string& service_instance_id,
       const BluetoothUUID& characteristic_uuid);
 
+  std::vector<device::BluetoothRemoteGattDescriptor*> GetDescriptorsByUUID(
+      device::BluetoothRemoteGattCharacteristic* characteristic,
+      const BluetoothUUID& descriptor_uuid);
+
  protected:
   // BluetoothGattConnection is a friend to call Add/RemoveGattConnection.
   friend BluetoothGattConnection;