bluetooth: Fix crash when a notification arrives during a write

device/bluetooth/bluetooth_remote_gatt_characteristic_mac.h

 // Copyright 2016 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_REMOTE_GATT_CHARACTERISTIC_MAC_H_
 #define DEVICE_BLUETOOTH_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_MAC_H_
 
 #include "device/bluetooth/bluetooth_remote_gatt_characteristic.h"
 
 #import <CoreBluetooth/CoreBluetooth.h>
@@ skipping 81 matching lines @@
   CBCharacteristic* GetCBCharacteristic() const;
   // Returns the mac adapter.
   BluetoothAdapterMac* GetMacAdapter() const;
   // Returns CoreBluetooth peripheral.
   CBPeripheral* GetCBPeripheral() const;
   // Returns true if this characteristic has been fully discovered.
   bool IsDiscoveryComplete() const;
   // Returns BluetoothRemoteGattDescriptorMac from CBDescriptor.
   BluetoothRemoteGattDescriptorMac* GetBluetoothRemoteGattDescriptorMac(
       CBDescriptor* cb_descriptor) const;
+  bool HasPendingRead() const {
+    return !read_characteristic_value_callbacks_.first.is_null();
+  };
+  bool HasPendingWrite() const {
+    return !write_characteristic_value_callbacks_.first.is_null();
+  };
   // Is true if the characteristic has been discovered with all its descriptors.
   bool is_discovery_complete_;
   // gatt_service_ owns instances of this class.
   BluetoothRemoteGattServiceMac* gatt_service_;
   // A characteristic from CBPeripheral.services.characteristics.
   base::scoped_nsobject<CBCharacteristic> cb_characteristic_;
   // Characteristic identifier.
   std::string identifier_;
   // Service UUID.
   BluetoothUUID uuid_;
   // Characteristic value.
   std::vector<uint8_t> value_;
-  // True if a gatt read or write request is in progress.
-  bool characteristic_value_read_or_write_in_progress_;
   // ReadRemoteCharacteristic request callbacks.
   std::pair<ValueCallback, ErrorCallback> read_characteristic_value_callbacks_;
   // WriteRemoteCharacteristic request callbacks.
   std::pair<base::Closure, ErrorCallback> write_characteristic_value_callbacks_;
   // Stores callbacks for SubscribeToNotifications and
   // UnsubscribeFromNotifications requests.
   typedef std::pair<base::Closure, ErrorCallback> PendingNotifyCallbacks;
   // Stores SubscribeToNotifications request callbacks.
   PendingNotifyCallbacks subscribe_to_notification_callbacks_;
   // Stores UnsubscribeFromNotifications request callbacks.
   PendingNotifyCallbacks unsubscribe_from_notification_callbacks_;
   // Map of descriptors, keyed by descriptor identifier.
   std::unordered_map<std::string,
                      std::unique_ptr<BluetoothRemoteGattDescriptorMac>>
       gatt_descriptor_macs_;
 };
 
 // Stream operator for logging.
 DEVICE_BLUETOOTH_EXPORT std::ostream& operator<<(
     std::ostream& out,
     const BluetoothRemoteGattCharacteristicMac& characteristic);
 
 }  // namespace device
 
 #endif  // DEVICE_BLUETOOTH_BLUETOOTH_REMOTE_GATT_CHARACTERISTIC_MAC_H_