Use VDC for API 21 and 22 to workaround the ImageView scaling issue

The appCompat change is independent of the change inside VDC and AVDC.
However, it is better to keep them behaves consistently, such that dev using
VDC / AVDC directly by JAVA will have the same behavior.

b/27449545

Change-Id: Idd3115ec00651885dc5a32c8e38a26d0fd3eb63d
3 files changed