title: When using Google Picker with drive.file scope, how long does access to selected files last?
body: <p>I have seen a few examples of folks using the Picker to select files and demonstrating that once the file is selected, it can be read, etc. But I am curious for how long the app's access to the file lasts once it has been picked. Is it indefinite? If not, how long does it last?</p>
  <p>And as a corollary, how does the Drive API &quot;know&quot; that the file I'm reading was just selected by the picker? Does it keep track internally somehow? I don't see any kind of token that gets passed to the API request. But maybe I'm missing it.</p>