Add initial Controller to DownloadService

components/download/internal/startup_status.h

Index: components/download/internal/startup_status.h
diff --git a/components/download/internal/startup_status.h b/components/download/internal/startup_status.h
new file mode 100644
index 0000000000000000000000000000000000000000..613fe15fec4e0fdef32f75aa69c8b64bd7f18949
--- /dev/null
+++ b/components/download/internal/startup_status.h
@@ -0,0 +1,37 @@
+// Copyright 2017 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.
+
+#ifndef COMPONENTS_DOWNLOAD_STARTUP_STATUS_H_
+#define COMPONENTS_DOWNLOAD_STARTUP_STATUS_H_
+
+#include "base/macros.h"
+#include "base/optional.h"
+
+namespace download {
+
+// Helper struct to track the initialization status of various Controller
+// internal components.
+struct StartupStatus {
+ public:

[xingliu, 2017/05/27 00:25:32]

optional nit: public can be removed.

[David Trainor- moved to gerrit, 2017/05/30 18:55:24]

Done.

+  StartupStatus();
+  ~StartupStatus();
+
+  base::Optional<bool> driver_ok;
+  base::Optional<bool> model_ok;
+
+  // Whether or not all components have finished initialization.  Note that this
+  // does not mean that all components were initialized successfully.
+  bool Complete() const;
+
+  // Whether or not all components have initialized successfully.  Should only
+  // be called if Complete() is true.
+  bool Ok() const;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StartupStatus);
+};
+
+}  // namespace download
+
+#endif  // COMPONENTS_DOWNLOAD_STARTUP_STATUS_H_