[Sync] Replace typedef with using.

ios/chrome/browser/sync/sync_setup_service.h

Index: ios/chrome/browser/sync/sync_setup_service.h
diff --git a/ios/chrome/browser/sync/sync_setup_service.h b/ios/chrome/browser/sync/sync_setup_service.h
index d18145b967a1644a1979568a76d1fd98ac906923..a8d14064a1ce20339daf9acf4960628f576ea698 100644
--- a/ios/chrome/browser/sync/sync_setup_service.h
+++ b/ios/chrome/browser/sync/sync_setup_service.h
@@ -26,7 +26,7 @@ class SyncSetupInProgressHandle;
 // to allow the complex sync setup flow on iOS.
 class SyncSetupService : public KeyedService {
  public:
-  typedef enum {
+  using SyncServiceState = enum {
     kNoSyncServiceError,
     kSyncServiceSignInNeedsUpdate,
     kSyncServiceCouldNotConnect,
@@ -34,10 +34,10 @@ class SyncSetupService : public KeyedService {
     kSyncServiceNeedsPassphrase,
     kSyncServiceUnrecoverableError,
     kLastSyncServiceError = kSyncServiceUnrecoverableError
-  } SyncServiceState;
+  };
 
   // The set of user-selectable datatypes handled by Chrome for iOS.
-  typedef enum {
+  using SyncableDatatype = enum {
     kSyncBookmarks,
     kSyncOmniboxHistory,
     kSyncPasswords,
@@ -46,7 +46,7 @@ class SyncSetupService : public KeyedService {
     kSyncPreferences,
     kSyncReadingList,
     kNumberOfSyncableDatatypes
-  } SyncableDatatype;
+  };
 
   SyncSetupService(syncer::SyncService* sync_service, PrefService* prefs);
   ~SyncSetupService() override;