Leftover cleanups from https://codereview.chromium.org/324493002 .

base/prefs/value_map_pref_store.cc

Index: base/prefs/value_map_pref_store.cc
diff --git a/base/prefs/value_map_pref_store.cc b/base/prefs/value_map_pref_store.cc
index 5e890e2589fb1a4cc2b78e03c143636239834605..8af12826df370c424dad4566493cf1a7790fda52 100644
--- a/base/prefs/value_map_pref_store.cc
+++ b/base/prefs/value_map_pref_store.cc
@@ -47,6 +47,11 @@ void ValueMapPrefStore::ReportValueChanged(const std::string& key) {
   FOR_EACH_OBSERVER(Observer, observers_, OnPrefValueChanged(key));
 }
 
+void ValueMapPrefStore::SetValueSilently(const std::string& key,
+                                         base::Value* value) {
+  prefs_.SetValue(key, value);
+}
+
 ValueMapPrefStore::~ValueMapPrefStore() {}
 
 void ValueMapPrefStore::NotifyInitializationCompleted() {