Don't interpret embeded NULLs in a response header line as a line terminator.

BUG=95992

Review URL: http://codereview.chromium.org/7796025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@100863 0039d316-1c4b-4281-b951-d872f2087c98
void HttpUtil::AppendHeaderIfMissing(const char* header_name,
                                     const std::string& header_value,
                                     std::string* headers) {
  if (header_value.empty())
    return;
  if (net::HttpUtil::HasHeader(*headers, header_name))
    return;
  *headers += std::string(header_name) + ": " + header_value + "\r\n";
}

void HttpUtil::AppendHeaderIfMissing(const char* header_name,
                                     const std::string& header_value,
                                     std::string* headers) {
  if (header_value.empty())
    return;
  if (net::HttpUtil::HasHeader(*headers, header_name))
    return;
  *headers += std::string(header_name) + ": " + header_value + "\r\n";
}
