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 389f34cca11678f01ac2f958e02a0d28cbc3fdd5..0bd58af2d8bbaf129d56a45d2943430ff1f30043 100644
--- a/chrome/browser/metrics/variations/variations_service.h
+++ b/chrome/browser/metrics/variations/variations_service.h
@@ -21,7 +21,7 @@
 #include "net/url_request/url_fetcher_delegate.h"
 
 class PrefService;
-class PrefServiceSimple;
+class PrefRegistrySimple;
 
 namespace chrome_variations {
 
@@ -47,7 +47,7 @@ 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();