Remove PrefObserver usage, batch 9.

chrome/browser/safe_browsing/safe_browsing_tab_observer.cc

Index: chrome/browser/safe_browsing/safe_browsing_tab_observer.cc
diff --git a/chrome/browser/safe_browsing/safe_browsing_tab_observer.cc b/chrome/browser/safe_browsing/safe_browsing_tab_observer.cc
index 06d4ca13518108496cdbecf9deb5040e514b1b7d..113e3b1b1258cd83b630ff1ab71a717865d92b8a 100644
--- a/chrome/browser/safe_browsing/safe_browsing_tab_observer.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_tab_observer.cc
@@ -38,7 +38,10 @@ SafeBrowsingTabObserver::SafeBrowsingTabObserver(
   PrefService* prefs = profile->GetPrefs();
   if (prefs) {
     pref_change_registrar_.Init(prefs);
-    pref_change_registrar_.Add(prefs::kSafeBrowsingEnabled, this);
+    pref_change_registrar_.Add(
+        prefs::kSafeBrowsingEnabled,
+        base::Bind(&SafeBrowsingTabObserver::UpdateSafebrowsingDetectionHost,
+                   base::Unretained(this)));
 
     if (prefs->GetBoolean(prefs::kSafeBrowsingEnabled) &&
         g_browser_process->safe_browsing_detection_service()) {
@@ -53,22 +56,6 @@ SafeBrowsingTabObserver::~SafeBrowsingTabObserver() {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// content::NotificationObserver overrides
-
-void SafeBrowsingTabObserver::OnPreferenceChanged(
-    PrefServiceBase* service,
-    const std::string& pref_name) {
-  Profile* profile =
-      Profile::FromBrowserContext(web_contents_->GetBrowserContext());
-  DCHECK(service == profile->GetPrefs());
-  if (pref_name == prefs::kSafeBrowsingEnabled) {
-    UpdateSafebrowsingDetectionHost();
-  } else {
-    NOTREACHED() << "unexpected pref change notification" << pref_name;
-  }
-}
-
-////////////////////////////////////////////////////////////////////////////////
 // Internal helpers
 
 void SafeBrowsingTabObserver::UpdateSafebrowsingDetectionHost() {