Remove PrefServiceSimple, replacing it with PrefService and PrefRegistrySimple.

base/prefs/public/pref_service_base.h

Index: base/prefs/public/pref_service_base.h
diff --git a/base/prefs/public/pref_service_base.h b/base/prefs/public/pref_service_base.h
index 4115fa4070389709ae40ce707b0733ed38c6f169..2a9c623d27929c5057897b26441d93681c9c2ad7 100644
--- a/base/prefs/public/pref_service_base.h
+++ b/base/prefs/public/pref_service_base.h
@@ -104,9 +104,6 @@ class PrefServiceBase {
   // value can be changed by the user.
   virtual bool IsUserModifiablePreference(const char* pref_name) const = 0;
 
-  // Unregisters a preference.
-  virtual void UnregisterPreference(const char* path) = 0;
-
   // Look up a preference.  Returns NULL if the preference is not
   // registered.
   virtual const Preference* FindPreference(const char* pref_name) const = 0;