Fix Smart Lock crash when resuming from suspend.

components/proximity_auth/proximity_auth_system.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 "components/proximity_auth/proximity_auth_system.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "base/time/default_tick_clock.h"
 #include "components/proximity_auth/logging/logging.h"
 #include "components/proximity_auth/proximity_auth_client.h"
@@ skipping 38 matching lines @@
 
 void ProximityAuthSystem::OnAuthAttempted(const std::string& user_id) {
   // TODO(tengs): There is no reason to pass the |user_id| argument anymore.
   unlock_manager_->OnAuthAttempted(ScreenlockBridge::LockHandler::USER_CLICK);
 }
 
 void ProximityAuthSystem::OnSuspend() {
   PA_LOG(INFO) << "Preparing for device suspension.";
   DCHECK(!suspended_);
   suspended_ = true;
+  unlock_manager_->SetRemoteDeviceLifeCycle(nullptr);
   remote_device_life_cycle_.reset();
 }
 
 void ProximityAuthSystem::OnSuspendDone() {
   PA_LOG(INFO) << "Device resumed from suspension.";
   DCHECK(suspended_);
 
   // TODO(tengs): On ChromeOS, the system's Bluetooth adapter is invalidated
   // when the system suspends. However, Chrome does not receive this
   // notification until a second or so after the system wakes up. That means
@@ skipping 39 matching lines @@
     PA_LOG(INFO) << "Creating RemoteDeviceLifeCycle for focused user.";
     remote_device_life_cycle_.reset(
         new RemoteDeviceLifeCycleImpl(remote_device_, proximity_auth_client_));
     unlock_manager_->SetRemoteDeviceLifeCycle(remote_device_life_cycle_.get());
     remote_device_life_cycle_->AddObserver(this);
     remote_device_life_cycle_->Start();
   }
 }
 
 }  // proximity_auth