Add PrefStore::GetValues

components/prefs/value_map_pref_store.cc

Index: components/prefs/value_map_pref_store.cc
diff --git a/components/prefs/value_map_pref_store.cc b/components/prefs/value_map_pref_store.cc
index 8b828b10d5c628cdc6b2bb9333269e0746554046..c31d7c771cc9358db4879386d37a53427e286363 100644
--- a/components/prefs/value_map_pref_store.cc
+++ b/components/prefs/value_map_pref_store.cc
@@ -17,6 +17,10 @@ bool ValueMapPrefStore::GetValue(const std::string& key,
   return prefs_.GetValue(key, value);
 }
 
+std::unique_ptr<base::DictionaryValue> ValueMapPrefStore::GetValues() const {
+  return prefs_.AsDictionaryValue();
+}
+
 void ValueMapPrefStore::AddObserver(PrefStore::Observer* observer) {
   observers_.AddObserver(observer);
 }