Improve performance of registering font preferences

chrome/browser/prefs/pref_service.h

Index: chrome/browser/prefs/pref_service.h
diff --git a/chrome/browser/prefs/pref_service.h b/chrome/browser/prefs/pref_service.h
index 94dc0f077caa1b6be042674be5d5472864f12f6b..e3237711e4e946cd9762865919a4e3aae700c466 100644
--- a/chrome/browser/prefs/pref_service.h
+++ b/chrome/browser/prefs/pref_service.h
@@ -183,6 +183,9 @@ class PrefService : public PrefServiceBase, public base::NonThreadSafe {
   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;
@@ -310,12 +313,31 @@ class PrefService : public PrefServiceBase, public base::NonThreadSafe {
 
   // 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);