Draft change to use base::Closure instead of PrefObserver in PrefChangeRegistrar.

chrome/browser/api/prefs/pref_member.cc

 // Copyright (c) 2012 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/api/prefs/pref_member.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/prefs/public/pref_service_base.h"
 #include "base/value_conversions.h"
@@ skipping 19 matching lines @@
   DCHECK(prefs);
   DCHECK(pref_name_.empty());  // Check that Init is only called once.
   observer_ = observer;
   prefs_ = prefs;
   pref_name_ = pref_name;
   // Check that the preference is registered.
   DCHECK(prefs_->FindPreference(pref_name_.c_str()))
       << pref_name << " not registered.";
 
   // Add ourselves as a pref observer so we can keep our local value in sync.
-  prefs_->AddPrefObserver(pref_name, this);
+  prefs_->AddPrefObserver(pref_name,
+                          base::Bind(&PrefMemberBase::OnPreferenceChanged,
+                                     base::Unretained(this), prefs, pref_name));
 }
 
 void PrefMemberBase::Destroy() {
   if (prefs_ && !pref_name_.empty()) {
-    prefs_->RemovePrefObserver(pref_name_.c_str(), this);
+    prefs_->RemovePrefObserver(pref_name_.c_str(),
+                               base::Bind(&PrefMemberBase::OnPreferenceChanged,
+                                          base::Unretained(this),
+                                          prefs_, pref_name_.c_str()));
     prefs_ = NULL;
   }
 }
 
 void PrefMemberBase::MoveToThread(
     const scoped_refptr<MessageLoopProxy>& message_loop) {
   VerifyValuePrefName();
   // Load the value from preferences if it hasn't been loaded so far.
   if (!internal())
     UpdateValueFromPref();
   internal()->MoveToThread(message_loop);
 }
 
 void PrefMemberBase::OnPreferenceChanged(PrefServiceBase* service,
                                          const std::string& pref_name) {

[Mattias Nissler (ping if slow), 2012/11/06 13:26:48]

doesn't require these parameters any longer, can just use |prefs_| and
|pref_name_|

   VerifyValuePrefName();
   UpdateValueFromPref();
   if (!setting_value_ && observer_)
     observer_->OnPreferenceChanged(service, pref_name);
 }
 
 void PrefMemberBase::UpdateValueFromPref() const {
   VerifyValuePrefName();
   const PrefServiceBase::Preference* pref =
       prefs_->FindPreference(pref_name_.c_str());
@@ skipping 126 matching lines @@
   ListValue list_value;
   list_value.AppendStrings(value);
   prefs()->Set(pref_name().c_str(), list_value);
 }
 
 template <>
 bool PrefMember<std::vector<std::string> >::Internal::UpdateValueInternal(
     const Value& value) const {
   return subtle::PrefMemberVectorStringUpdate(value, &value_);
 }