Two phases to set the password for disk encryption

Revert "Revert "Two phases to set the password for disk encryption""

This reverts commit d402389290eeef86be7eb9241e20fdd125d44eb1.

In addition, fix the bug in the original commit.

Bug: 28154455
Bug: 28694324
Change-Id: I885f1d73e739416347c135d79979941c2bbdbe62
3 files changed