private void succeedEntries() {
   // Do not allocate the iterator here.
   for (int i = 0; i < entries.size(); ++i) {
     FrameEntry entry = entries.get(i);
     notifyCallbackSuccess(entry.callback);
     entry.release();
   }
   entries.clear();
 }
 @Override
 public void onCompleteFailure(Throwable x) {
   for (FrameEntry entry : entries) {
     notifyCallbackFailure(entry.callback, x);
     entry.release();
   }
   entries.clear();
   failure = x;
   onFailure(x);
 }