Revert 170483 - Remove PrefObserver usages, batch 12.

TBR=ben@chromium.org
BUG=155525


Review URL: https://chromiumcodereview.appspot.com/11280115

Reason for revert: A review comment after commit showed that the
change is probably wrong (or at least changes behavior in a way that
was not intended). Reverting for now, until there is time to figure
out the correct change.

TBR=joi@chromium.org
Review URL: https://codereview.chromium.org/11308295

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@170519 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 12 insertions, 9 deletions

diff --git a/chrome/browser/ui/alternate_error_tab_observer.cc b/chrome/browser/ui/alternate_error_tab_observer.cc
index 6bac4c3..569a739 100644
--- a/chrome/browser/ui/alternate_error_tab_observer.cc
+++ b/chrome/browser/ui/alternate_error_tab_observer.cc
@@ -25,11 +25,7 @@ AlternateErrorPageTabObserver::AlternateErrorPageTabObserver(
   PrefService* prefs = profile_->GetPrefs();
   if (prefs) {
     pref_change_registrar_.Init(prefs);
-    pref_change_registrar_.Add(
-        prefs::kAlternateErrorPagesEnabled,
-        base::Bind(&AlternateErrorPageTabObserver::
-                       OnAlternateErrorPagesEnabledChanged,
-                   base::Unretained(this)));
+    pref_change_registrar_.Add(prefs::kAlternateErrorPagesEnabled, this);
   }
 
   registrar_.Add(this, chrome::NOTIFICATION_GOOGLE_URL_UPDATED,
@@ -65,6 +61,17 @@ void AlternateErrorPageTabObserver::Observe(
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// PrefObserver overrides
+
+void AlternateErrorPageTabObserver::OnPreferenceChanged(
+    PrefServiceBase* service,
+    const std::string& pref_name) {
+  DCHECK_EQ(profile_->GetPrefs(), service);
+  DCHECK(prefs::kAlternateErrorPagesEnabled == pref_name);
+  UpdateAlternateErrorPageURL(web_contents()->GetRenderViewHost());
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // Internal helpers
 
 GURL AlternateErrorPageTabObserver::GetAlternateErrorPageURL() const {
@@ -83,10 +90,6 @@ GURL AlternateErrorPageTabObserver::GetAlternateErrorPageURL() const {
   return url;
 }
 
-void AlternateErrorPageTabObserver::OnAlternateErrorPagesEnabledChanged() {
-  UpdateAlternateErrorPageURL(web_contents()->GetRenderViewHost());
-}
-
 void AlternateErrorPageTabObserver::UpdateAlternateErrorPageURL(
     RenderViewHost* rvh) {
   rvh->SetAltErrorPageURL(GetAlternateErrorPageURL());