title: Removing and adding activities to the back stack
body: <p>In the "System Back after cross navigation to lower hierarchy levels" section of the <a href="http://developer.android.com/design/patterns/navigation-drawer.html" rel="noreferrer">Navigation Drawer</a>, they say:</p>
  
  <blockquote>
    <p>If the user navigates to a lower hierarchy screen from the navigation
    drawer and the screen has a direct parent, then the Back stack is
    reset and Back points to the target screen’s parent. This Back
    behavior is the same as when a user navigates into an app from a
    notification.</p>
  </blockquote>
  
  <p><img src="https://i.stack.imgur.com/5jhkX.png" alt="resetting the back stack"></p>
  
  <p>I know the back stack can be reset by starting an activity with FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_NEW_TASK, but that does not seem to be usable here, as it would not create a back stack for Lower 1.1.1.</p>
  
  <p>Any idea how to remove TopView2 from the stack and at the same time add the TopView1 -> Lower 1.1 back stack when starting Lower 1.1.1 ? I'm expecting a simple solution, considering this is mentioned in the Navigation Drawer document.</p>