Remove PrefObserver usage, batch 9.

chrome/browser/profiles/gaia_info_update_service.cc

Index: chrome/browser/profiles/gaia_info_update_service.cc
diff --git a/chrome/browser/profiles/gaia_info_update_service.cc b/chrome/browser/profiles/gaia_info_update_service.cc
index 4d8b4a8935c26d056b45ac46e2d4cb5bdc7f614e..f555991c6039decab782901f7f605602a1ba30fe 100644
--- a/chrome/browser/profiles/gaia_info_update_service.cc
+++ b/chrome/browser/profiles/gaia_info_update_service.cc
@@ -32,7 +32,9 @@ const int kMinUpdateIntervalSeconds = 5;
 GAIAInfoUpdateService::GAIAInfoUpdateService(Profile* profile)
     : profile_(profile) {
   PrefService* prefs = profile_->GetPrefs();
-  username_pref_.Init(prefs::kGoogleServicesUsername, prefs, this);
+  username_pref_.Init(prefs::kGoogleServicesUsername, prefs,
+                      base::Bind(&GAIAInfoUpdateService::OnUsernameChanged,
+                                 base::Unretained(this)));
 
   last_updated_ = base::Time::FromInternalValue(
       prefs->GetInt64(prefs::kProfileGAIAInfoUpdateTime));
@@ -164,12 +166,6 @@ void GAIAInfoUpdateService::OnProfileDownloadFailure(
   ScheduleNextUpdate();
 }
 
-void GAIAInfoUpdateService::OnPreferenceChanged(PrefServiceBase* service,
-                                                const std::string& pref_name) {
-  if (prefs::kGoogleServicesUsername == pref_name)
-    OnUsernameChanged();
-}
-
 void GAIAInfoUpdateService::OnUsernameChanged() {
   ProfileInfoCache& cache =
       g_browser_process->profile_manager()->GetProfileInfoCache();