Delete the PreferenceMACs on profile deletion.

services/preferences/persistent_pref_store_impl.cc

Index: services/preferences/persistent_pref_store_impl.cc
diff --git a/services/preferences/persistent_pref_store_impl.cc b/services/preferences/persistent_pref_store_impl.cc
index f5b4ae14d6531ebcd6fce4032741eeacf8c06a93..7ed38b6513d35dbf0bacef0087c861ade14c4587 100644
--- a/services/preferences/persistent_pref_store_impl.cc
+++ b/services/preferences/persistent_pref_store_impl.cc
@@ -62,6 +62,9 @@ class PersistentPrefStoreImpl::Connection : public mojom::PersistentPrefStore {
     pref_store_->SchedulePendingLossyWrites();
   }
   void ClearMutableValues() override { pref_store_->ClearMutableValues(); }
+  void OnStoreDeletionFromDisk() override {
+    pref_store_->OnStoreDeletionFromDisk();
+  }
 
   void OnConnectionError() { pref_store_->OnConnectionError(this); }
 
@@ -183,6 +186,10 @@ void PersistentPrefStoreImpl::ClearMutableValues() {
   backing_pref_store_->ClearMutableValues();
 }
 
+void PersistentPrefStoreImpl::OnStoreDeletionFromDisk() {
+  backing_pref_store_->OnStoreDeletionFromDisk();
+}
+
 void PersistentPrefStoreImpl::OnConnectionError(Connection* connection) {
   connections_.erase(connection);
 }