Explicitly ShutdownOnUIThread the HostContentSettingsMap when destroying the Profile.

chrome/browser/content_settings/content_settings_notification_provider.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_NOTIFICATION_PROVIDER_H_
 #define CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_NOTIFICATION_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 37 matching lines @@
       ContentSetting content_setting);
 
   virtual void GetAllContentSettingsRules(
       ContentSettingsType content_type,
       const ResourceIdentifier& resource_identifier,
       Rules* content_setting_rules) const;
 
   virtual void ClearAllContentSettingsRules(
       ContentSettingsType content_type);
 
+  virtual void ShutdownOnUIThread();
+
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
  private:
   void StartObserving();
   void StopObserving();
 
   void OnPrefsChanged(const std::string& pref_name);
 
@@ skipping 27 matching lines @@
 
   PrefChangeRegistrar prefs_registrar_;
   NotificationRegistrar notification_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationProvider);
 };
 
 }  // namespace content_settings
 
 #endif  // CHROME_BROWSER_CONTENT_SETTINGS_CONTENT_SETTINGS_NOTIFICATION_PROVIDER_H_