Verify ProximityAuthProfilePrefManager local state before persisting to it.

The local_state_ pointer was initializing to garbage memory when Chrome was run
in debug mode, causing a check if local_state_ == nullptr to incorrectly return false.
leading to a crash. This issue was preventing developers from running Chrome in debug
mode if Smart Lock is enabled.

Bug: 881958
Change-Id: Ia796eefe244ca17a1905e489aeee9a310828802c
Reviewed-on: https://chromium-review.googlesource.com/1218442Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590379}

chromeos/components/proximity_auth/proximity_auth_profile_pref_manager.cc

@@ -195,7 +195,7 @@ void ProximityAuthProfilePrefManager::OnFeatureStatesChanged(
   }
   feature_state_ = it->second;
 
-  if (local_state_)
+  if (local_state_ && account_id_.is_valid())
     SyncPrefsToLocalState();
 }
 

chromeos/components/proximity_auth/proximity_auth_profile_pref_manager.h

@@ -79,20 +79,20 @@ class ProximityAuthProfilePrefManager
 
   // Contains perferences that outlive the lifetime of this object and across
   // process restarts. Not owned and must outlive this instance.
-  PrefService* pref_service_;
+  PrefService* pref_service_ = nullptr;
 
   // Listens to pref changes so they can be synced to the local state.
   PrefChangeRegistrar registrar_;
 
   // The local state to which to sync the profile prefs.
-  PrefService* local_state_;
+  PrefService* local_state_ = nullptr;
 
   // The account id of the current profile.
   AccountId account_id_;
 
   // Used to determine the FeatureState of Smart Lock. See |feature_state_|.
   chromeos::multidevice_setup::MultiDeviceSetupClient*
-      multidevice_setup_client_;
+      multidevice_setup_client_ = nullptr;
 
   // Caches feature state of Smart Lock. Populated by using
   // |multidevice_setup_client_|.