tree 28be8874eb403e5c32c6b9b1d0529f8d051ce1d8
parent dd66de13ea0461e133070d2a09a7befdd576f427
author Yo Chiang <yochiang@google.com> 1602051600 +0800
committer Yo Chiang <yochiang@google.com> 1602576043 +0800

Add IVold::destroyDsuMetadataKey()

destroyDsuMetadataKey() / destroy_dsu_metadata_key() calls
android::gsi::GetDsuMetadataKeyDir() to query the DSU metadata
encryption key dir and destroy the key.
This releases the resource and allows consecutive DSU installations to
use the same key *directory*, but not the same key *blob*.

Bug: 168571434
Test: 1. Install a DSU system.
  2. Boot the DSU system and reboot back to the host system.
  3. Wipe the DSU installation.
  4. DSU metadata key dir /metadata/vold/metadata_encryption/dsu/dsu is
     destroyed.
Change-Id: Ib851177315a5a266807f46ccfd446de1848232cf