Remove PrefServiceSimple, replacing it with PrefService and PrefRegistrySimple.

chrome/browser/metrics/variations/variations_service.h

Index: chrome/browser/metrics/variations/variations_service.h
diff --git a/chrome/browser/metrics/variations/variations_service.h b/chrome/browser/metrics/variations/variations_service.h
index cd5bd36cd199912fb0d43d478409f9cfcbdb2cd2..30b6f319654b7d53be8c3055b97b6fa7f6799f61 100644
--- a/chrome/browser/metrics/variations/variations_service.h
+++ b/chrome/browser/metrics/variations/variations_service.h
@@ -25,7 +25,7 @@
 #endif
 
 class PrefService;
-class PrefServiceSimple;
+class PrefRegistrySimple;
 
 namespace chrome_variations {
 
@@ -56,7 +56,7 @@ class VariationsService
   void SetCreateTrialsFromSeedCalledForTesting(bool called);
 
   // Register Variations related prefs in Local State.
-  static void RegisterPrefs(PrefServiceSimple* prefs);
+  static void RegisterPrefs(PrefRegistrySimple* prefs);
 
   // Factory method for creating a VariationsService.
   static VariationsService* Create();