app_shell: Initial skeleton of a GCD target device setup API

extensions/shell/common/api/shell_gcd.idl

+// Copyright 2014 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.
+
+// Setup related functions for a Google Cloud Devices (GCD) target device
+// running on Chrome OS Core. The actual bootstrapping and GCD registration is
+// handled by the privetd and buffet system daemons.
+namespace shell.gcd {
+
+  enum BootstrapStatus {
+    // Attempting to bootstrap onto Wi-Fi network.
+    bootstrapping,

[Ken Rockot(use gerrit already), 2014/10/30 20:47:21]

nit: I think the term "bootstrap" is being overloaded in this enum

[James Cook, 2014/10/30 21:30:50]

Maybe it should be SetupStatus?

I was trying to follow naming conventions from this doc's state diagram:

https://docs.google.com/a/google.com/document/d/1NeVPsiyZe2gjisNdK4Ce_Yb1kpUp...

+    
+    // Has bootstrapped, connecting to Wi-Fi.
+    connecting,
+    
+    // Has connected, registering with GCD backend.
+    registering,
+    
+    // Bootstrap completed.
+    completed
+  };
+  
+  callback BootstrapStatusCallback = void(BootstrapStatus status);
+
+  interface Functions {
+    // Returns the current bootstrap status via |callback|.
+    static void GetBootstrapStatus(BootstrapStatusCallback callback);

[Ken Rockot(use gerrit already), 2014/10/30 20:47:21]

nit: getBootstrapStatus

[James Cook, 2014/10/30 21:30:50]

Good catch.

+  };
+  
+  interface Events {
+    // Notifies that bootstrapping has transitioned to a new |status|.
+    static void onBootstrapStatusChanged(BootstrapStatus status);
+  };
+};