Define canonical enum for "HeliumResult" status values.

blimp/net/helium/helium_errors.h

Index: blimp/net/helium/helium_errors.h
diff --git a/blimp/net/helium/helium_errors.h b/blimp/net/helium/helium_errors.h
new file mode 100644
index 0000000000000000000000000000000000000000..687b4b42de1894596e5b54b9320e794c2889d158
--- /dev/null
+++ b/blimp/net/helium/helium_errors.h
@@ -0,0 +1,14 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file intentionally does not have header guards, it's included
+// inside a macro to generate enum values.
+
+// This file contains the list of Helium error codes.
+
+HELIUM_ERROR(INTERNAL_ERROR, 1)

[Wez, 2016/10/08 00:44:53]

nit: Should this be UNKNOWN_ERROR? i.e. it indicates some condition that we
really never expected could possibly occur?

+
+// The operation could not be performed because the connection to the peer was
+// lost.
+HELIUM_ERROR(DISCONNECTED, 2)