Don't allow extensions to take screenshots of interstitial pages. Branched from
https://codereview.chromium.org/14885004/ which is trying to test it.

BUG=229504

Review URL: https://chromiumcodereview.appspot.com/14954004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198297 0039d316-1c4b-4281-b951-d872f2087c98
void TabsUpdateFunction::OnExecuteCodeFinished(const std::string& error,
                                              int32 on_page_id,
                                              const GURL& url,
                                              const ListValue& script_result) {
  if (error.empty())
    PopulateResult();
  else
    error_ = error;
  SendResponse(error.empty());
}

void TabsUpdateFunction::OnExecuteCodeFinished(const std::string& error,
                                              int32 on_page_id,
                                              const GURL& url,
                                              const ListValue& script_result) {
  if (error.empty())
    PopulateResult();
  else
    error_ = error;
  SendResponse(error.empty());
}
