Add ScopedKeepAlive to c/b/lifetime

chrome/browser/lifetime/keep_alive_types.h

Index: chrome/browser/lifetime/keep_alive_types.h
diff --git a/chrome/browser/lifetime/keep_alive_types.h b/chrome/browser/lifetime/keep_alive_types.h
new file mode 100644
index 0000000000000000000000000000000000000000..04a4124f0303a4955212579a7c06c679fa20b58f
--- /dev/null
+++ b/chrome/browser/lifetime/keep_alive_types.h
@@ -0,0 +1,30 @@
+// 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.
+
+#ifndef CHROME_BROWSER_LIFETIME_KEEP_ALIVE_TYPES_H_
+#define CHROME_BROWSER_LIFETIME_KEEP_ALIVE_TYPES_H_
+
+#include <ostream>
+
+enum class KeepAliveOrigin {
+  // for tests
+  TEST,

[sky, 2016/02/25 18:43:50]

Is there a reason tests can't use one of the values below?

[dgn, 2016/02/25 20:08:50]

No...

+
+  // c/b/background
+  BACKGROUND_MODE_MANAGER,
+
+  // c/b/ui
+  APP_LIST_SERVICE_VIEWS,
+  APP_LIST_SHOWER,
+  CHROME_APP_DELEGATE,
+  PANEL_VIEW,
+  PROFILE_LOADER,
+  USER_MANAGER_VIEW
+};
+
+#ifndef NDEBUG
+std::ostream& operator<<(std::ostream& out, const KeepAliveOrigin& origin);
+#endif  // ndef NDEBUG
+
+#endif  // CHROME_BROWSER_LIFETIME_KEEP_ALIVE_TYPES_H_