CCodec: don't drop metadata for output with flag FLAG_DROP_FRAME.

Bug: 151995371
Test: local test ok.
Change-Id: I882b791f3d16a17ffd47ce0bf9e40c64c8b90357
(cherry picked from commit 55eff1412e942c13b0fc4af1f846843a554d7068)
1 file changed