Adds async interface method to PersistentPrefStore.

chrome/browser/prefs/testing_pref_store.cc

Index: chrome/browser/prefs/testing_pref_store.cc
diff --git a/chrome/browser/prefs/testing_pref_store.cc b/chrome/browser/prefs/testing_pref_store.cc
index e85a8368364e8f255be2cb070297676c37cc5314..ebcb87164b9000413f881ffa459f3daddb934925 100644
--- a/chrome/browser/prefs/testing_pref_store.cc
+++ b/chrome/browser/prefs/testing_pref_store.cc
@@ -55,9 +55,15 @@ bool TestingPrefStore::ReadOnly() const {
 
 PersistentPrefStore::PrefReadError TestingPrefStore::ReadPrefs() {
   prefs_.Clear();
+  NotifyInitializationCompleted();
   return PersistentPrefStore::PREF_READ_ERROR_NONE;
 }
 
+void TestingPrefStore::ReadPrefsAsync(ReadErrorDelegate* error_delegate) {
+  prefs_.Clear();
+  NotifyInitializationCompleted();
+}
+
 bool TestingPrefStore::WritePrefs() {
   prefs_written_ = true;
   return prefs_written_;
@@ -73,7 +79,7 @@ void TestingPrefStore::NotifyPrefValueChanged(const std::string& key) {
 }
 
 void TestingPrefStore::NotifyInitializationCompleted() {
-  FOR_EACH_OBSERVER(Observer, observers_, OnInitializationCompleted());
+  FOR_EACH_OBSERVER(Observer, observers_, OnInitializationCompleted(true));
 }
 
 void TestingPrefStore::ReportValueChanged(const std::string& key) {