Smart Lock: Clean up EasyUnlockService subclass pointers on Shutdown.

Likely fixes crashes during shutdown seen in Smart Lock.

R=hansberry@chromium.org

Bug: 969142
Fixes: 969142
Test: none
Change-Id: I9c55e5995c27c2a93005e549a98b319f056123a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1639320
Commit-Queue: James Hawkins <jhawkins@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665584}

chrome/browser/chromeos/login/easy_unlock/easy_unlock_service_regular.cc

@@ -385,6 +385,7 @@ void EasyUnlockServiceRegular::InitializeInternal() {
 
 void EasyUnlockServiceRegular::ShutdownInternal() {
   pref_manager_.reset();
+  notification_controller_.reset();
 
   proximity_auth::ScreenlockBridge::Get()->RemoveObserver(this);
 

chrome/browser/chromeos/login/easy_unlock/easy_unlock_service_signin_chromeos.cc

@@ -321,6 +321,10 @@ void EasyUnlockServiceSignin::ShutdownInternal() {
     return;
   service_active_ = false;
 
+  remote_device_cache_.reset();
+  challenge_wrapper_.reset();
+  pref_manager_.reset();
+
   weak_ptr_factory_.InvalidateWeakPtrs();
   proximity_auth::ScreenlockBridge::Get()->RemoveObserver(this);
   user_data_.clear();