Implement BluetoothGattNotifySession::Stop on Android, 2nd attempt

device/bluetooth/bluetooth_gatt_notify_session.cc

 // 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.
 
 #include "device/bluetooth/bluetooth_gatt_notify_session.h"
 
+#include "base/bind.h"
+#include "base/logging.h"
+#include "device/bluetooth/bluetooth_remote_gatt_characteristic.h"
+
 namespace device {
 
-BluetoothGattNotifySession::BluetoothGattNotifySession() {
+BluetoothGattNotifySession::BluetoothGattNotifySession(
+    base::WeakPtr<BluetoothRemoteGattCharacteristic> characteristic)
+    : characteristic_(characteristic),
+      characteristic_id_(characteristic.get() ? characteristic->GetIdentifier()
+                                              : std::string()) {}
+
+BluetoothGattNotifySession::~BluetoothGattNotifySession() {
+  if (characteristic_ != nullptr) {
+    Stop(base::Bind(&base::DoNothing));
+  }
 }
 
-BluetoothGattNotifySession::~BluetoothGattNotifySession() {
+std::string BluetoothGattNotifySession::GetCharacteristicIdentifier() const {
+  return characteristic_id_;
+}
+
+BluetoothRemoteGattCharacteristic*
+BluetoothGattNotifySession::GetCharacteristic() const {
+  return characteristic_.get();
+}
+
+bool BluetoothGattNotifySession::IsActive() {
+  return characteristic_ != nullptr && characteristic_->IsNotifying();
+}
+
+void BluetoothGattNotifySession::Stop(const base::Closure& callback) {
+  BluetoothRemoteGattCharacteristic* characteristic = characteristic_.get();
+  characteristic_.reset();
+  if (characteristic != nullptr) {
+    characteristic->StopNotifySession(this, callback);
+  } else {
+    callback.Run();
+  }
 }
 
 }  // namespace device