Use PrefChangeRegistrar everywhere

chrome/browser/prefs/pref_change_registrar.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prefs/pref_change_registrar.h"
 
 #include "chrome/browser/prefs/pref_service.h"
 
 PrefChangeRegistrar::PrefChangeRegistrar() : service_(NULL) {}
 
 PrefChangeRegistrar::~PrefChangeRegistrar() {
-  if (service_) {
-    for (std::set<ObserverRegistration>::const_iterator it = observers_.begin();
-         it != observers_.end(); ++it) {
-      service_->RemovePrefObserver(it->first.c_str(), it->second);
-    }
-  }
+  RemoveAll();
 }
 
 void PrefChangeRegistrar::Init(PrefService* service) {
-  DCHECK(!service_);
+  DCHECK(IsEmpty() || service_ == service);
   service_ = service;
 }
 
 void PrefChangeRegistrar::Add(const char* path, NotificationObserver* obs) {
   if (!service_) {
     NOTREACHED();
     return;
   }
   ObserverRegistration registration(path, obs);
   if (observers_.find(registration) != observers_.end()) {
@@ skipping 12 matching lines @@
   ObserverRegistration registration(path, obs);
   std::set<ObserverRegistration>::iterator it =
        observers_.find(registration);
   if (it == observers_.end()) {
     NOTREACHED();
     return;
   }
   service_->RemovePrefObserver(it->first.c_str(), it->second);
   observers_.erase(it);
 }
+
+void PrefChangeRegistrar::RemoveAll() {
+  if (service_) {
+    for (std::set<ObserverRegistration>::const_iterator it = observers_.begin();
+         it != observers_.end(); ++it) {
+      service_->RemovePrefObserver(it->first.c_str(), it->second);
+    }
+    observers_.clear();
+  }
+}
+
+bool PrefChangeRegistrar::IsEmpty() const {
+  return observers_.empty();
+}