Show different error message if ARC is disabled.

chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h

Index: chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h
diff --git a/chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h b/chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h
index 0de66140e7f44791a56a30bd5d5cae713349ba17..036f7d93a63a2c42caa6d8af1872ca86cc3fc5e0 100644
--- a/chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h
+++ b/chrome/browser/chromeos/arc/auth/arc_auth_info_fetcher.h
@@ -11,18 +11,26 @@
 
 namespace arc {
 
+enum class ArcAuthInfoFetchStatus {
+  SUCCESS,       // The fetch was successful.
+  FAILURE,       // The request failed.
+  ARC_DISABLED,  // ARC is not enabled.
+  SIZE,          // The size of this enum; keep last.

[Luis Héctor Chávez, 2017/02/21 19:32:11]

Do you *need* the SIZE? Seems like you're only using this in tests and not for
UMA purposes, so you should be able to remove it and also remove all default:
labels in all the switch blocks where you use ArcAuthInfoFetchStatus, that way
the compiler will complain if you are not being exhaustive in the switch.

Also, how about moving this enum into ArcAuthInfoFetcher? That way it will be
ArcAuthInfoFetcher::Status :)

[Marton Hunyady, 2017/02/22 16:07:54]

Done. (This also means I can't forward declare it in arc_auth_service.h)

+};
+
 // Interface to implement auth_code or enrollment token fetching.
 class ArcAuthInfoFetcher {
  public:
   virtual ~ArcAuthInfoFetcher() = default;
 
-  // Fetches the auth code or the enrollment token. On success, |callback| is
-  // called with the fetched |auth_info|. Otherwise, |callback| is called with
-  // empty string.
+  // Fetches the auth code or the enrollment token.
+  // On success, |callback| is called with status = SUCCESS and with the fetched

[Luis Héctor Chávez, 2017/02/21 19:32:11]

nit: "|status|". Same below.

[Marton Hunyady, 2017/02/22 16:07:54]

Done.

+  // |auth_info|. Otherwise, status contains the reason of the failure.
   // Fetch() should be called once per instance, and it is expected that
   // the inflight operation is cancelled without calling the |callback|
   // when the instance is deleted.
-  using FetchCallback = base::Callback<void(const std::string& auth_info)>;
+  using FetchCallback = base::Callback<void(ArcAuthInfoFetchStatus status,
+                                            const std::string& auth_info)>;
   virtual void Fetch(const FetchCallback& callback) = 0;
 };