title: how to hide chrome created website app title-bar
body: <p>I created an application extension from chrome, and I want to hide the bar of information:<br />
  <a href="https://i.stack.imgur.com/BlTdR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/BlTdR.png" alt="enter image description here"></a></p>
  
  <p>I want to hie the green area, which is show's in the above picture.</p>