[Sync] Rename syncable_prefs to sync_preferences.

chrome/browser/prefs/pref_metrics_service.h

Index: chrome/browser/prefs/pref_metrics_service.h
diff --git a/chrome/browser/prefs/pref_metrics_service.h b/chrome/browser/prefs/pref_metrics_service.h
index 6e61bb536b58831572fc140a86f6bbb2362a885a..88454b01287f2f50ec81e248f43c5cfa31f85d4e 100644
--- a/chrome/browser/prefs/pref_metrics_service.h
+++ b/chrome/browser/prefs/pref_metrics_service.h
@@ -15,7 +15,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 #include "components/keyed_service/core/keyed_service.h"
-#include "components/syncable_prefs/synced_pref_change_registrar.h"
+#include "components/sync_preferences/synced_pref_change_registrar.h"
 
 class PrefRegistrySimple;
 
@@ -89,7 +89,7 @@ class PrefMetricsService : public KeyedService {
   PrefService* prefs_;
   PrefService* local_state_;
 
-  std::unique_ptr<syncable_prefs::SyncedPrefChangeRegistrar>
+  std::unique_ptr<sync_preferences::SyncedPrefChangeRegistrar>
       synced_pref_change_registrar_;
 
   base::WeakPtrFactory<PrefMetricsService> weak_factory_;