Legacy icon treatment

- normalize
- circle detection
b/36563706

LEGACY_ICON_TREATMENT can only be turned on IF DISABLE_ICON_NORMALIZATION is false.
This is fine since, when all apps migrated to adaptive icons
we won't need icon normalization AND we won't need legacy icon treatment.


Change-Id: Ic5745a5c521e670ce699f6a74733739cb7986f71