Bluetooth: macOS: Adding counter for service discovery callbacks.

device/bluetooth/bluetooth_low_energy_device_mac.h

Index: device/bluetooth/bluetooth_low_energy_device_mac.h
diff --git a/device/bluetooth/bluetooth_low_energy_device_mac.h b/device/bluetooth/bluetooth_low_energy_device_mac.h
index e33d5398ea023a8d1d06ab9781f6b24c03fe6042..b25bfff5aecc901ecf69e6055aee8140767817b7 100644
--- a/device/bluetooth/bluetooth_low_energy_device_mac.h
+++ b/device/bluetooth/bluetooth_low_energy_device_mac.h
@@ -107,6 +107,9 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothLowEnergyDeviceMac
   friend class BluetoothTestMac;
   friend class BluetoothRemoteGattServiceMac;
 
+  // Calls the macOS to discover primary services.
+  void DiscoverPrimaryServices();
+
   // Sends notification if this device is ready with all services discovered.
   void SendNotificationIfDiscoveryComplete();
 
@@ -140,6 +143,11 @@ class DEVICE_BLUETOOTH_EXPORT BluetoothLowEnergyDeviceMac
   // identifier.
   std::string hash_address_;
 
+  // Increases each time -[CBPeripheral discoverServices:] is called, and
+  // decreases each time DidDiscoverPrimaryServices() is called. Once the
+  // value is set to 0, characteristics and properties are discovered.
+  int discovery_pending_count_;
+
   DISALLOW_COPY_AND_ASSIGN(BluetoothLowEnergyDeviceMac);
 };