Initialize focus overlay manager if it is not initialized.

Camera open thread initializes the focus overlay manager
after opening camera. In a rare scenario above background
thread had not initialized focus overlay manager by the
time UI thread start acessesing it, so we see a crash.
Initialize focus overlay manager from UI thread if it is
not initialized already.

Change-Id: I1635c8759d0e0647fe61fe975a0cc24df40df529
1 file changed