De-flake BluetoothLowEnergyWeave* tests.

components/proximity_auth/ble/bluetooth_low_energy_weave_client_connection_unittest.cc

 // 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.
 
 #include "components/proximity_auth/ble/bluetooth_low_energy_weave_client_connection.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
@@ skipping 343 matching lines @@
         generator_factory_(
             new MockBluetoothLowEnergyWeavePacketGeneratorFactory()),
         receiver_factory_(
             new MockBluetoothLowEnergyWeavePacketReceiverFactory()) {
     BluetoothLowEnergyWeavePacketGenerator::Factory::SetInstanceForTesting(
         generator_factory_);
     BluetoothLowEnergyWeavePacketReceiver::Factory::SetInstanceForTesting(
         receiver_factory_);
   }
 
+  ~ProximityAuthBluetoothLowEnergyWeaveClientConnectionTest() override {
+    BluetoothLowEnergyWeavePacketGenerator::Factory::SetInstanceForTesting(
+        nullptr);
+    BluetoothLowEnergyWeavePacketReceiver::Factory::SetInstanceForTesting(
+        nullptr);
+  }
+
   void SetUp() override {
     device_ = base::MakeUnique<NiceMock<device::MockBluetoothDevice>>(
         adapter_.get(), 0, kTestRemoteDeviceName,
         kTestRemoteDeviceBluetoothAddress, false, false);
 
     service_ = base::MakeUnique<NiceMock<device::MockBluetoothGattService>>(
         device_.get(), kServiceID, service_uuid_, true, false);
     tx_characteristic_ =
         base::MakeUnique<NiceMock<device::MockBluetoothGattCharacteristic>>(
             service_.get(), kTXCharacteristicID, tx_characteristic_uuid_, false,
@@ skipping 666 matching lines @@
           adapter_, kTestRemoteDeviceBluetoothAddress));
 
   CharacteristicsFound(connection.get());
   NotifySessionStarted(connection.get());
   ConnectionResponseReceived(connection.get(), kDefaultMaxPacketSize);
 }
 
 }  // namespace weave
 
 }  // namespace proximity_auth