\mode<presentation>

\setbeamertemplate{navigation symbols}{}

\newif\ifbeamer@secheader
\beamer@secheaderfalse

\DeclareOptionBeamer{secheader}{\beamer@secheadertrue}
\ProcessOptionsBeamer

\usecolortheme{X}
\useinnertheme[shadow]{rounded}
\useoutertheme{infolines}

\ifbeamer@secheader\else\setbeamertemplate{headline}[default]\fi

\mode
<all>