Don't delete the current NavigationEntry when leaving an interstitial page.

BUG=107182
TEST=See bug

Review URL: http://codereview.chromium.org/8976014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@115189 0039d316-1c4b-4281-b951-d872f2087c98
  void OnCheckBrowseURLDone(const GURL& gurl, Client* client) {
    SafeBrowsingService::SafeBrowsingCheck check;
    check.urls.push_back(gurl);
    check.client = client;
    check.result = badurls[gurl.spec()];
    client->OnSafeBrowsingResult(check);
  }

  void OnCheckBrowseURLDone(const GURL& gurl, Client* client) {
    SafeBrowsingService::SafeBrowsingCheck check;
    check.urls.push_back(gurl);
    check.client = client;
    check.result = badurls[gurl.spec()];
    client->OnSafeBrowsingResult(check);
  }
