Function-type templated CallbackRegistry

chrome/browser/chromeos/settings/cros_settings.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_SETTINGS_CROS_SETTINGS_H_
 #define CHROME_BROWSER_CHROMEOS_SETTINGS_CROS_SETTINGS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 76 matching lines @@
   // Helper function for the whitelist op. Implemented here because we will need
   // this in a few places. The functions searches for |email| in the pref |path|
   // It respects whitelists so foo@bar.baz will match *@bar.baz too.
   bool FindEmailInList(const std::string& path, const std::string& email) const;
 
   // Adding/removing of providers.
   bool AddSettingsProvider(CrosSettingsProvider* provider);
   bool RemoveSettingsProvider(CrosSettingsProvider* provider);
 
   // Add an observer Callback for changes for the given |path|.
-  typedef base::CallbackRegistry<void>::Subscription ObserverSubscription;
+  typedef base::CallbackRegistry<void(void)>::Subscription ObserverSubscription;
   scoped_ptr<ObserverSubscription> AddSettingsObserver(
       const std::string& path,
       const base::Closure& callback);
 
   // Returns the provider that handles settings with the |path| or prefix.
   CrosSettingsProvider* GetProvider(const std::string& path) const;
 
  private:
   friend class CrosSettingsTest;
 
   // Fires system setting change callback.
   void FireObservers(const std::string& path);
 
   // List of ChromeOS system settings providers.
   std::vector<CrosSettingsProvider*> providers_;
 
   // A map from settings names to a list of observers. Observers get fired in
   // the order they are added.
-  typedef base::hash_map<std::string, base::CallbackRegistry<void>*>
+  typedef base::hash_map<std::string, base::CallbackRegistry<void(void)>*>
       SettingsObserverMap;
   SettingsObserverMap settings_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(CrosSettings);
 };
 
 // Helper class for tests. Initializes the CrosSettings singleton on
 // construction and tears it down again on destruction.
 class ScopedTestCrosSettings {
  public:
   ScopedTestCrosSettings();
   ~ScopedTestCrosSettings();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedTestCrosSettings);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_SETTINGS_CROS_SETTINGS_H_