Replace base::CallbackList with base::ObserverList in CastConfigDelegate

chrome/browser/ui/ash/cast_config_delegate_chromeos.cc

Index: chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc b/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
index 2a210710c50458c2628a5fa54a0a0b4d1235c029..5be07bfcc78a7669e181f26a7290ebde487ea25a 100644
--- a/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/cast_config_delegate_chromeos.cc
@@ -65,11 +65,15 @@ bool CastConfigDelegateChromeos::HasCastExtension() const {
   return FindCastExtension() != nullptr;
 }
 
-CastConfigDelegateChromeos::DeviceUpdateSubscription
-CastConfigDelegateChromeos::RegisterDeviceUpdateObserver(
-    const ReceiversAndActivitesCallback& callback) {
-  auto listeners = extensions::CastDeviceUpdateListeners::Get(GetProfile());
-  return listeners->RegisterCallback(callback);
+void CastConfigDelegateChromeos::AddObserver(
+    ash::CastConfigDelegate::Observer* observer) {
+  return extensions::CastDeviceUpdateListeners::Get(GetProfile())
+      ->AddObserver(observer);
+}
+void CastConfigDelegateChromeos::RemoveObserver(
+    ash::CastConfigDelegate::Observer* observer) {
+  return extensions::CastDeviceUpdateListeners::Get(GetProfile())
+      ->RemoveObserver(observer);
 }
 
 void CastConfigDelegateChromeos::RequestDeviceRefresh() {