Revert "Change input injection security model to require INJECT_..."

Revert submission 17125748-require-inject-events-permission

Reason for revert: b/228203157, b/228194124
Reverted Changes:
Ib0d66eff3:Change input injection security model to require I...
Ief1a2f10c:Update WindowInputTests after changing injection p...
Ie2d8d0c3d:Change input injection security model to require I...

Change-Id: Iab079575c41821f5330002e23dc13884676a5249
9 files changed