Fix crash when Proximity Auth BLE stops the discovery session.

components/proximity_auth/ble/bluetooth_low_energy_connection_finder.cc

 // Copyright 2015 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 "components/proximity_auth/ble/bluetooth_low_energy_connection_finder.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 111 matching lines @@
 
 void BluetoothLowEnergyConnectionFinder::StopDiscoverySession() {
   VLOG(1) << "Stopping discovery sesison";
 
   if (!adapter_) {
     VLOG(1) << "Adapter not initialized";
     return;
   }
   if (!discovery_session_ || !discovery_session_->IsActive()) {
     VLOG(1) << "No Active discovery session";
+    return;
   }
 
   discovery_session_->Stop(
       base::Bind(&BluetoothLowEnergyConnectionFinder::OnDiscoverySessionStopped,
                  weak_ptr_factory_.GetWeakPtr()),
       base::Bind(
           &BluetoothLowEnergyConnectionFinder::OnStopDiscoverySessionError,
           weak_ptr_factory_.GetWeakPtr()));
 }
 
@@ skipping 33 matching lines @@
           << "device = " << remote_device->GetAddress()
           << ", name = " << remote_device->GetName();
   remote_device->CreateGattConnection(
       base::Bind(&BluetoothLowEnergyConnectionFinder::OnConnectionCreated,
                  weak_ptr_factory_.GetWeakPtr()),
       base::Bind(&BluetoothLowEnergyConnectionFinder::OnCreateConnectionError,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 }  // namespace proximity_auth