title: How to use chrome extension filesystem api?
body: <p>Hi as example i want to read </p>
  
  <pre><code>c:/x.txt
  </code></pre>
  
  <p>as text</p>
  
  <p>and write? is there any example about chrome.fileSystem ?</p>
  
  <p>Notice : I don't want to ask the path of file to user</p>