title: Support v7 MenuPopupHelper is now hidden and restricted to LIBRARY_GROUP
body: <p>Recently i've been getting a lint error on my usage of <code>android.support.v7.view.menu.MenuPopupHelper</code> which is now hidden and restricted to be only used within its library group.</p>
  
  <p><strong>Exact message:</strong></p>
  
  <p><code>MenuPopupHelper constructor can only be called from within the same library group (groupId=com.android.support)</code></p>
  
  <p><strong>Excerpt from the <code>MenuPopupHelper.java</code> class:</strong></p>
  
  <pre><code>/**
   * Presents a menu as a small, simple popup anchored to another view.
   *
   * @hide
   */
  @RestrictTo(LIBRARY_GROUP)
  public class MenuPopupHelper implements MenuHelper {
  </code></pre>
  
  <p><strong>Question:</strong>
  Any idea when and why this happened ? or whats the workaround that I should look for ?</p>