code: public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
          Session session = sessionTracker.getSession();
          if (session != null) {
              return session.onActivityResult((Activity)getContext(), requestCode,
                      resultCode, data);
          } else {
              return false;
          }
      }
docs: Provides an implementation for {@link Activity#onActivityResult
  onActivityResult} that updates the Session based on information returned
  during the authorization flow. The Activity containing this view
  should forward the resulting onActivityResult call here to
  update the Session state based on the contents of the resultCode and
  data.
  
  @param requestCode
  The requestCode parameter from the forwarded call. When this
  onActivityResult occurs as part of Facebook authorization
  flow, this value is the activityCode passed to open or
  authorize.
  @param resultCode
  An int containing the resultCode parameter from the forwarded
  call.
  @param data
  The Intent passed as the data parameter from the forwarded
  call.
  @return A boolean indicating whether the requestCode matched a pending
  authorization request for this Session.
  @see Session#onActivityResult(Activity, int, int, Intent)