title: Using underscore templates in a chrome app
body: <p>I am building a chrome app and getting an unsafe eval error.
  I know that eval is now allowed on chrome extensions but when I am adding to the manifest </p>
  
  <pre><code>  "content_security_policy": "default-src  'unsafe-eval'; script-src   'unsafe-eval' 'unsafe-inline'; style-src 'unsafe-inline'"
  </code></pre>
  
  <p>I get an error in the extension tab</p>
  
  <pre><code>'content_security_policy' is only allowed for extensions and legacy packaged apps, but this is a packaged app.
  </code></pre>
  
  <p>Is there a way to allow unsafe eval in a chrome app</p>