Implement BluetoothRemoteGattCharacteristicWin::StartNotifySession and related unit tests

device/bluetooth/bluetooth_low_energy_win.h

 // Copyright 2014 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.
 
 #ifndef DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_WIN_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_WIN_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 158 matching lines @@
       const PBTH_LE_GATT_CHARACTERISTIC characteristic,
       scoped_ptr<BTH_LE_GATT_CHARACTERISTIC_VALUE>* out_value);
 
   // Writes |characteristic| value in service with service device path
   // |service_path| to |*new_value|.
   virtual HRESULT WriteCharacteristicValue(
       base::FilePath& service_path,
       const PBTH_LE_GATT_CHARACTERISTIC characteristic,
       PBTH_LE_GATT_CHARACTERISTIC_VALUE new_value);
 
+  // Register GATT events of |event_type| in the service with service device
+  // path |service_path|. |event_parameter| is the event's parameter. |callback|
+  // is the function to be invoked if the event happened. |context| is the input
+  // parameter to be given back through |callback|. |*out_handle| stores the
+  // unique handle in OS for this registration.

[ortuno, 2016/03/15 02:55:31]

Could you add here that this function will write to the CCC descriptor?

[gogerald1, 2016/03/15 18:28:22]

May not good since I do not see Windows implementation code. OS may implement it
in another way, like polling.

[gogerald1, 2016/03/17 14:07:56]

Add similar comments in bluetooth_remote_gatt_characteristic_win.cc

[ortuno, 2016/03/21 17:00:52]

I thought you said you tested it and it does write to the descriptor?

[gogerald1, 2016/03/21 22:09:16]

No, I said I tested the functionality of these interfaces, for this interface it
means I can receive characteristic value change notification from my mobile
after calling this interface.

[ortuno, 2016/03/22 15:02:24]

Maybe a little context will make it clear why we need to know if the descriptor
was written. Devices that support notifications are not always sending out
notifications. They only start sending notifications once the CCC descriptor has
been written to. If Windows doesn't write to the descriptor then we are going to
start getting reports of people not getting any notifications from their
devices. So please find out whether or not BluetoothGATTRegisterEvent writes to
the CCC descriptor or not.

[gogerald1, 2016/03/29 15:12:00]

Done. From HCI log, Windows does not write CCCD implicitly, modified by setting
CCCD explicitly, verified by HCI log.

+  virtual HRESULT RegisterGattEvents(base::FilePath& service_path,
+                                     BTH_LE_GATT_EVENT_TYPE event_type,
+                                     PVOID event_parameter,
+                                     PFNBLUETOOTH_GATT_EVENT_CALLBACK callback,
+                                     PVOID context,
+                                     BLUETOOTH_GATT_EVENT_HANDLE* out_handle);
+  virtual HRESULT UnregisterGattEvent(BLUETOOTH_GATT_EVENT_HANDLE event_handle);
+
  protected:
   BluetoothLowEnergyWrapper();
   virtual ~BluetoothLowEnergyWrapper();
 };
 
 }  // namespace win
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_LOW_ENERGY_WIN_H_