Clear notifier when PrefService is destroyed.

chrome/browser/prefs/pref_service.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/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 207 matching lines @@
 PrefService::~PrefService() {
   DCHECK(CalledOnValidThread());
   STLDeleteContainerPointers(prefs_.begin(), prefs_.end());
   prefs_.clear();
 
   // Reset pointers so accesses after destruction reliably crash.
   pref_value_store_.reset();
   user_pref_store_ = NULL;
   default_store_ = NULL;
   pref_sync_associator_.reset();
+  pref_notifier_.reset();

[Bernhard Bauer, 2012/06/08 13:08:46]

I don't really understand. What does this change do? Note that |pref_notifier_|
is a scoped_ptr member of PrefService, so it should be destroyed immediately
after the destructor runs, no?

 }
 
 void PrefService::InitFromStorage(bool async) {
   if (!async) {
     ReadErrorHandler error_handler;
     error_handler.OnError(user_pref_store_->ReadPrefs());
   } else {
     // Guarantee that initialization happens after this function returned.
     MessageLoop::current()->PostTask(
         FROM_HERE,
@@ skipping 753 matching lines @@
   return pref_value_store()->PrefValueFromDefaultStore(name_.c_str());
 }
 
 bool PrefService::Preference::IsUserModifiable() const {
   return pref_value_store()->PrefValueUserModifiable(name_.c_str());
 }
 
 bool PrefService::Preference::IsExtensionModifiable() const {
   return pref_value_store()->PrefValueExtensionModifiable(name_.c_str());
 }