tree 18d6a0d1ebe0f73c266a8194823c4ad4565615b5
parent 9cf526274905ff47ff26eab088c803916e7112d3
author Sen Jiang <senj@google.com> 1548368870 -0800
committer Treehugger Robot <treehugger-gerrit@google.com> 1550819167 +0000

Use string for Signatures protobuf.

To avoid conversion between brillo::Blob and string.
Also use SerializeToString() instead of AppendToString().

Test: update_engine_unittests
Change-Id: I0ad0fb5f45223f9f51f940de727660a9e62052bb