Bootstrapping: Send meaningful error code/message from Slave to Master

components/pairing/bluetooth_host_pairing_controller.h

Index: components/pairing/bluetooth_host_pairing_controller.h
diff --git a/components/pairing/bluetooth_host_pairing_controller.h b/components/pairing/bluetooth_host_pairing_controller.h
index 9c84a0d3dfa4d3f6340bfc8dc06372a45a90b905..8405ae0e95b86b56ecbd5513bac63f9d7b81b69f 100644
--- a/components/pairing/bluetooth_host_pairing_controller.h
+++ b/components/pairing/bluetooth_host_pairing_controller.h
@@ -74,6 +74,7 @@ class BluetoothHostPairingController
 
   void ChangeStage(Stage new_stage);
   void SendHostStatus();
+  void SendErrorCodeAndMessage();
 
   void OnGetAdapter(scoped_refptr<device::BluetoothAdapter> adapter);
   void SetName();
@@ -110,6 +111,8 @@ class BluetoothHostPairingController
   void OnUpdateStatusChanged(UpdateStatus update_status) override;
   void OnEnrollmentStatusChanged(EnrollmentStatus enrollment_status) override;
   void SetPermanentId(const std::string& permanent_id) override;
+  void SetErrorCodeAndMessage(int error_code,
+                              const std::string& error_message) override;
   void Reset() override;
 
   // ProtoDecoder::Observer:
@@ -149,6 +152,9 @@ class BluetoothHostPairingController
   std::string controller_device_address_;
   bool was_powered_ = false;
 
+  int error_code_ = 0;
+  std::string error_message_;
+
   scoped_refptr<device::BluetoothAdapter> adapter_;
   scoped_refptr<device::BluetoothSocket> service_socket_;
   scoped_refptr<device::BluetoothSocket> controller_socket_;