Remove some dead code about "acknowledged types"

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index f40ac51e93bda65448bb5706489188ba75b71882..aa1f46086850031eb7d351654622c89c3d1c3a72 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -702,10 +702,6 @@ class ProfileSyncService : public ProfileSyncServiceBase,
   // Resets the flag for suppressing sync startup and starts the sync backend.
   virtual void UnsuppressAndStart();
 
-  // Marks all currently registered types as "acknowledged" so we won't prompt
-  // the user about them any more.
-  void AcknowledgeSyncedTypes();
-
   SyncErrorController* sync_error_controller() {
     return sync_error_controller_.get();
   }