Fix crash with mismatched vector sizes.

BUG=169295
Review URL: https://codereview.chromium.org/11817050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176252 0039d316-1c4b-4281-b951-d872f2087c98
void SavePackage::OnDownloadDestroyed(DownloadItem* download) {
  StopObservation();
}

void SavePackage::OnDownloadDestroyed(DownloadItem* download) {
  StopObservation();
}
