device/bluetooth: Introduce BluetoothGattConnection.

device/bluetooth/bluetooth_gatt_connection.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_GATT_CONNECTION_H_
+#define DEVICE_BLUETOOTH_BLUETOOTH_GATT_CONNECTION_H_
+
+#include "base/callback.h"
+
+namespace device {
+
+// BluetoothGattConnection represents a GATT connection to a Bluetooth device
+// that has GATT services. Instances are obtained from a BluetoothDevice,
+// and the connection is kept alive as long as there is at least one
+// active BluetoothGattConnection object. BluetoothGattConnection objects
+// automatically update themselves, when the connection is terminated by the
+// operating system (e.g. due to user action).
+class BluetoothGattConnection {
+ public:
+  // Destructor automatically closes this GATT connection. If this is the last
+  // remaining GATT connection and this results in a call to the OS, that call
+  // may not always succeed. Users can make an explicit call to
+  // BluetoothGattConnection::Close to make sure that they are notified of
+  // a possible error via the callback.
+  virtual ~BluetoothGattConnection();
+
+  // Returns true if the connection is active.
+  virtual bool IsActive() const = 0;

[keybuk, 2014/06/17 21:41:06]

nit: "Connected" makes much more sense than "Active"

[armansito, 2014/06/18 02:03:06]

Done.

+
+  // Disconnects this GATT connection and calls |callback| upon completion.
+  // After a successful invocation, the device may still remain connected due to
+  // other GATT connections.
+  virtual void Disconnect(const base::Closure& callback) = 0;
+
+ protected:
+  BluetoothGattConnection();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BluetoothGattConnection);
+};
+
+}  // namespace device
+
+#endif  //  DEVICE_BLUETOOTH_BLUETOOTH_GATT_CONNECTION_H_