mash: Move session_types.h to ash/public

ash/public/cpp/session_types.h

 // Copyright 2015 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 ASH_COMMON_SESSION_SESSION_TYPES_H_
-#define ASH_COMMON_SESSION_SESSION_TYPES_H_
+#ifndef ASH_PUBLIC_CPP_SESSION_TYPES_H_
+#define ASH_PUBLIC_CPP_SESSION_TYPES_H_
 
 namespace ash {
 
 // The index of the user profile to use. The list is always LRU sorted so that
 // index 0 is the currently active user.
 using UserIndex = int;
 
 // Represents possible user adding scenarios.
 enum class AddUserSessionPolicy {
   // Adding a user is allowed.
   ALLOWED,
   // Disallowed due to primary user's policy.
   ERROR_NOT_ALLOWED_PRIMARY_USER,
   // Disallowed due to no eligible users.
   ERROR_NO_ELIGIBLE_USERS,
   // Disallowed due to reaching maximum supported user.
   ERROR_MAXIMUM_USERS_REACHED,
 };
 
 }  // namespace ash
 
-#endif  // ASH_COMMON_SESSION_SESSION_TYPES_H_
+#endif  // ASH_PUBLIC_CPP_SESSION_TYPES_H_