DividerView choreographer set earlier to avoid null exception

DividerView sometimes gets attached (after created) after minimized mode
has triggered and therefore causes choreographer to trigger a null
exception. So put it in the constructor to avoid this issue.

Change-Id: Iad32fa42ab2bc60bde4ac0be8f8eac8b55de40ae
Fixes: 38017227
Test: manual - hard to repro, keep rotating screen while minimized