Skip non-critical updates during OOBE update check

If the system has not yet completed OOBE, and Omaha returns a response
with an empty deadline field, avoid initiating a background update
because doing so may violate an enterprise policy that gets pushed
down post-enrollment.

Bug: None
BUG=chromium:587101
TEST=`FEATURES=test emerge-link chromeos-base/update_engine`
TEST=powerwash, install lsb-release file from an old stable build,
     repeat OOBE, verify that download is skipped via logs, then verify
     that update proceeds after logging into a standard gmail account

Change-Id: I6e6fae02c609b2763abc6e9960bf6d87dd3534e2
diff --git a/metrics_utils.cc b/metrics_utils.cc
index 11260fc..e165e89 100644
--- a/metrics_utils.cc
+++ b/metrics_utils.cc
@@ -99,7 +99,10 @@
     case ErrorCode::kDownloadInvalidMetadataSignature:
     case ErrorCode::kOmahaResponseInvalid:
     case ErrorCode::kOmahaUpdateIgnoredPerPolicy:
+    // TODO(deymo): The next two items belong in their own category; they
+    // should not be counted as internal errors. b/27112092
     case ErrorCode::kOmahaUpdateDeferredPerPolicy:
+    case ErrorCode::kNonCriticalUpdateInOOBE:
     case ErrorCode::kOmahaErrorInHTTPResponse:
     case ErrorCode::kDownloadMetadataSignatureMissingError:
     case ErrorCode::kOmahaUpdateDeferredForBackoff:
@@ -193,6 +196,7 @@
     case ErrorCode::kOmahaResponseInvalid:
     case ErrorCode::kOmahaUpdateIgnoredPerPolicy:
     case ErrorCode::kOmahaUpdateDeferredPerPolicy:
+    case ErrorCode::kNonCriticalUpdateInOOBE:
     case ErrorCode::kOmahaErrorInHTTPResponse:
     case ErrorCode::kDownloadOperationHashMissingError:
     case ErrorCode::kDownloadMetadataSignatureMissingError: