Remove PrefObserver usages, batch 12.

chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc

Index: chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc
index b72cb255b7a911f671a26c6c3f4326ee9f0e1461..9fcfc557994f8fe158bedd1499b959b11c868936 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_per_browser.cc
@@ -174,7 +174,11 @@ ChromeLauncherControllerPerBrowser::ChromeLauncherControllerPerBrowser(
                               chrome::NOTIFICATION_EXTENSION_UNLOADED,
                               content::Source<Profile>(profile_));
   pref_change_registrar_.Init(profile_->GetPrefs());
-  pref_change_registrar_.Add(prefs::kPinnedLauncherApps, this);
+  pref_change_registrar_.Add(
+      prefs::kPinnedLauncherApps,
+      base::Bind(&ChromeLauncherControllerPerBrowser::
+                     UpdateAppLaunchersFromPref,
+                 base::Unretained(this)));
 }
 
 ChromeLauncherControllerPerBrowser::~ChromeLauncherControllerPerBrowser() {
@@ -231,6 +235,8 @@ void ChromeLauncherControllerPerBrowser::Init() {
     PrefService* prefs = profile_->GetPrefs();
     if (prefs->GetString(prefs::kShelfAlignmentLocal).empty() ||
         prefs->GetString(prefs::kShelfAutoHideBehaviorLocal).empty()) {
+      // This causes OnIsSyncingChanged to be called when the value of
+      // PrefService::IsSyncing() changes.
       prefs->AddObserver(this);
     }
     ash::Shell::GetInstance()->AddShellObserver(this);
@@ -788,20 +794,6 @@ void ChromeLauncherControllerPerBrowser::Observe(
   }
 }
 
-void ChromeLauncherControllerPerBrowser::OnPreferenceChanged(
-    PrefServiceBase* service,
-    const std::string& pref_name) {
-  if (pref_name == prefs::kPinnedLauncherApps) {
-    UpdateAppLaunchersFromPref();
-  } else if (pref_name == prefs::kShelfAlignmentLocal) {
-    SetShelfAlignmentFromPrefs();
-  } else if (pref_name == prefs::kShelfAutoHideBehaviorLocal) {
-    SetShelfAutoHideBehaviorFromPrefs();
-  } else {
-    NOTREACHED() << "Unexpected pref change for " << pref_name;
-  }
-}
-
 void ChromeLauncherControllerPerBrowser::OnShelfAlignmentChanged() {
   const char* pref_value = NULL;
   // TODO(oshima): Support multiple displays.
@@ -870,7 +862,11 @@ void ChromeLauncherControllerPerBrowser::PersistPinnedState() {
       }
     }
   }
-  pref_change_registrar_.Add(prefs::kPinnedLauncherApps, this);
+  pref_change_registrar_.Add(
+      prefs::kPinnedLauncherApps,
+      base::Bind(&ChromeLauncherControllerPerBrowser::
+                     UpdateAppLaunchersFromPref,
+                 base::Unretained(this)));
 }
 
 ash::LauncherModel* ChromeLauncherControllerPerBrowser::model() {