Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/prefs/incognito_mode_prefs.h

Index: chrome/browser/prefs/incognito_mode_prefs.h
diff --git a/chrome/browser/prefs/incognito_mode_prefs.h b/chrome/browser/prefs/incognito_mode_prefs.h
index fb8c54bc8ef1fb06cc9e303aa212a0d1926a61b2..dc1afaa19d96b99a7185e3508a3992b7470e82e8 100644
--- a/chrome/browser/prefs/incognito_mode_prefs.h
+++ b/chrome/browser/prefs/incognito_mode_prefs.h
@@ -9,6 +9,7 @@
 
 class CommandLine;
 class PrefService;
+class PrefServiceSyncable;
 
 // Specifies Incognito mode availability preferences.
 class IncognitoModePrefs {
@@ -30,7 +31,7 @@ class IncognitoModePrefs {
   };
 
   // Register incognito related preferences.
-  static void RegisterUserPrefs(PrefService* prefs);
+  static void RegisterUserPrefs(PrefServiceSyncable* prefs);
 
   // Returns kIncognitoModeAvailability preference value stored
   // in the given pref service.