Improve performance of registering font preferences

chrome/browser/prefs/pref_service.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.
 
 // This provides a way to access the application's current preferences.
 
 // Chromium settings and storage represent user-selected preferences and
 // information and MUST not be extracted, overwritten or modified except
 // through Chromium defined APIs.
 
@@ skipping 165 matching lines @@
                                    PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterIntegerPref(const char* path,
                                    int default_value,
                                    PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterDoublePref(const char* path,
                                   double default_value,
                                   PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterStringPref(const char* path,
                                   const std::string& default_value,
                                   PrefSyncStatus sync_status) OVERRIDE;
+  virtual void RegisterStringPrefIfNew(const char* path,
+                                       const std::string& default_value,
+                                       PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterFilePathPref(const char* path,
                                     const FilePath& default_value,
                                     PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterListPref(const char* path,
                                 PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterDictionaryPref(const char* path,
                                       PrefSyncStatus sync_status) OVERRIDE;
   virtual void RegisterListPref(const char* path,
                                 base::ListValue* default_value,
                                 PrefSyncStatus sync_status) OVERRIDE;
@@ skipping 107 matching lines @@
                                content::NotificationObserver* obs) OVERRIDE;
   virtual void RemovePrefObserver(const char* path,
                                   content::NotificationObserver* obs) OVERRIDE;
 
   // Sends notification of a changed preference. This needs to be called by
   // a ScopedUserPrefUpdate if a DictionaryValue or ListValue is changed.
   void ReportUserPrefChanged(const std::string& key);
 
   // Registers a new preference at |path|. The |default_value| must not be
   // NULL as it determines the preference value's type.
+  // This will only be called once we have checked that the preference is new.
+  // RegisterNewPreference must not be called twice for the same path.
+  // This method takes ownership of |default_value|.
+  void RegisterNewPreference(const char* path,
+                        Value* default_value,
+                        PrefSyncStatus sync_status);
+
+  // Registers a new preference at |path|. The |default_value| must not be
+  // NULL as it determines the preference value's type.
   // RegisterPreference must not be called twice for the same path.
   // This method takes ownership of |default_value|.
   void RegisterPreference(const char* path,
                           base::Value* default_value,
                           PrefSyncStatus sync_status);
 
+  // Registers a preference at |path|. The |default_value| must not be
+  // NULL as it determines the preference value's type.
+  // This does nothing if the preference is already registered.
+  // This method takes ownership of |default_value|.
+  // Introduced to improve performance by avoiding the need for a check before
+  // calling RegisterPreference.
+  void RegisterPreferenceIfNew(const char* path,
+                               base::Value* default_value,
+                               PrefSyncStatus sync_status);
+
   // Sets the value for this pref path in the user pref store and informs the
   // PrefNotifier of the change.
   void SetUserPrefValue(const char* path, base::Value* new_value);
 
   // Load preferences from storage, attempting to diagnose and handle errors.
   // This should only be called from the constructor.
   void InitFromStorage(bool async);
 
   // Used to set the value of dictionary or list values in the user pref store.
   // This will create a dictionary or list if one does not exist in the user
@@ skipping 25 matching lines @@
   // CreatePrefServiceWithPerTabPrefStore() have been called to create a
   // "forked" PrefService.
   bool pref_service_forked_;
 
   ObserverList<PrefServiceObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
 #endif  // CHROME_BROWSER_PREFS_PREF_SERVICE_H_