Adds async interface method to PersistentPrefStore.

chrome/browser/prefs/overlay_persistent_pref_store.cc

Index: chrome/browser/prefs/overlay_persistent_pref_store.cc
diff --git a/chrome/browser/prefs/overlay_persistent_pref_store.cc b/chrome/browser/prefs/overlay_persistent_pref_store.cc
index e75fbc66b33a72da7e94f61e6d04867f6b903973..b47dab6e14df2bbaed0b0bd20236bfb5b8b54232 100644
--- a/chrome/browser/prefs/overlay_persistent_pref_store.cc
+++ b/chrome/browser/prefs/overlay_persistent_pref_store.cc
@@ -80,9 +80,21 @@ bool OverlayPersistentPrefStore::ReadOnly() const {
 
 PersistentPrefStore::PrefReadError OverlayPersistentPrefStore::ReadPrefs() {
   // We do not read intentionally.
+  OnInitializationCompleted();
   return PersistentPrefStore::PREF_READ_ERROR_NONE;
 }
 
+void OverlayPersistentPrefStore::ReadPrefsAsync() {
+  // We do not read intentionally.
+  OnInitializationCompleted();
+}
+
+void OverlayPersistentPrefStore::GetErrors(PrefReadError* error,
+                                           bool* is_fatal) {
+  (*error) = PersistentPrefStore::PREF_READ_ERROR_NONE;
+  (*is_fatal) = false;
+}
+
 bool OverlayPersistentPrefStore::WritePrefs() {
   // We do not write intentionally.
   return true;