AppCache: fix a browser crashing bug that can happen during updates.

BUG=558589

Review URL: https://codereview.chromium.org/1463463003

Cr-Commit-Position: refs/heads/master@{#360967}
void AppCacheUpdateJob::OnServiceReinitialized(
    AppCacheStorageReference* old_storage_ref) {
  if (old_storage_ref->storage() == storage_)
    disabled_storage_reference_ = old_storage_ref;
}

void AppCacheUpdateJob::OnServiceReinitialized(
    AppCacheStorageReference* old_storage_ref) {
  if (old_storage_ref->storage() == storage_)
    disabled_storage_reference_ = old_storage_ref;
}
