Revert "hwui: remove FatVector"

Revert "libui: rewrite Region with FatVector"

Revert submission 10248126-fatvector-region

Reason for revert: b/149254345
Reverted Changes:
I09dc2fddd:hwui: remove FatVector
I265c6c831:libui: rewrite Region with FatVector

also fix wrong license in FatVector.h

Test: boots
Bug: 149254345

Change-Id: I8ac66acb8b635324051edd41c5d4092c223157ff