Fix incorrect border after folding/unfolding the device

The display size is changed after folding/unfolding the device.
We need to refetch the size to draw the correct boundary on
the screen. Display#realSize is not updated in time, so we get the
bounds directly from windowConfiguration.

Bug: 190007130
Test: manual test
Change-Id: I942e333f62510650eec8b49d77ccf46a85a7457e