update_engine: Report VPD write failure to UMA

Currently we see many first actives to come from non-FSI images. But we have not
been able to figure out why. This CL, reports a new error
kFirstActiveOmahaPingSentPersistenceError when writing the first active omaha
flag into VPD fails. This allows us to see if that is the actual cause of the
problem.

CL:1062659 adds the enum value on the Chrome side.

BUG=chromium:833980
TEST=unittests
TEST=precq

Change-Id: I65e233c5f895489ba905494fb20d7b00d0c4af10
Reviewed-on: https://chromium-review.googlesource.com/1062662
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/common/error_code_utils.cc b/common/error_code_utils.cc
index a0e75f0e..2a2a0a3e 100644
--- a/common/error_code_utils.cc
+++ b/common/error_code_utils.cc
@@ -152,6 +152,8 @@ string ErrorCodeToString(ErrorCode code) {
       return "ErrorCode::kNoUpdate";
     case ErrorCode::kRollbackNotPossible:
       return "ErrorCode::kRollbackNotPossible";
+    case ErrorCode::kFirstActiveOmahaPingSentPersistenceError:
+      return "ErrorCode::kFirstActiveOmahaPingSentPersistenceError";
       // Don't add a default case to let the compiler warn about newly added
       // error codes which should be added here.
   }