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/bind_helpers.h"
+#include "base/callback.h"
 #include "base/location.h"
 #include "base/prefs/public/pref_service_base.h"
 #include "base/value_conversions.h"
 
 using base::MessageLoopProxy;
 
 namespace subtle {
 
 PrefMemberBase::PrefMemberBase()
-    : observer_(NULL),
+    : observer_(base::Bind(&base::DoNothing)),
       prefs_(NULL),
       setting_value_(false) {
 }
 
 PrefMemberBase::~PrefMemberBase() {
   Destroy();
 }
 
 void PrefMemberBase::Init(const char* pref_name,
                           PrefServiceBase* prefs,
-                          PrefObserver* observer) {
+                          const base::Closure& observer) {
+  observer_ = observer;
+  Init(pref_name, prefs);
+}
+
+void PrefMemberBase::Init(const char* pref_name,
+                          PrefServiceBase* prefs) {
   DCHECK(pref_name);
   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);
 }
 
@@ skipping 10 matching lines @@
   // 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) {
   VerifyValuePrefName();
   UpdateValueFromPref();
-  if (!setting_value_ && observer_)
-    observer_->OnPreferenceChanged(service, pref_name);
+  if (!setting_value_)
+    observer_.Run();
 }
 
 void PrefMemberBase::UpdateValueFromPref() const {
   VerifyValuePrefName();
   const PrefServiceBase::Preference* pref =
       prefs_->FindPreference(pref_name_.c_str());
   DCHECK(pref);
   if (!internal())
     CreateInternal();
   internal()->UpdateValue(pref->GetValue()->DeepCopy(),
@@ skipping 122 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_);
 }