Delete the PreferenceMACs on profile deletion.

services/preferences/tracked/segregated_pref_store.cc

Index: services/preferences/tracked/segregated_pref_store.cc
diff --git a/services/preferences/tracked/segregated_pref_store.cc b/services/preferences/tracked/segregated_pref_store.cc
index af7349e0382f6a9ba07df994d017d85ac762eef8..7202cb842930358f259937a3244e0b8c9a76a833 100644
--- a/services/preferences/tracked/segregated_pref_store.cc
+++ b/services/preferences/tracked/segregated_pref_store.cc
@@ -174,6 +174,11 @@ void SegregatedPrefStore::ClearMutableValues() {
   NOTIMPLEMENTED();
 }
 
+void SegregatedPrefStore::OnStoreDeletionFromDisk() {
+  default_pref_store_->OnStoreDeletionFromDisk();
+  selected_pref_store_->OnStoreDeletionFromDisk();
+}
+
 SegregatedPrefStore::~SegregatedPrefStore() {
   default_pref_store_->RemoveObserver(&aggregating_observer_);
   selected_pref_store_->RemoveObserver(&aggregating_observer_);