ash: Use enum for SessionController::CycleActiveUser

ash/public/cpp/session_types.h

Index: ash/public/cpp/session_types.h
diff --git a/ash/public/cpp/session_types.h b/ash/public/cpp/session_types.h
index c5c59f031e36e3a5bdb5d2e8a3b2f9c93e56c1a8..7916b26b6adf75e98e67dacf43bc980de5c3325b 100644
--- a/ash/public/cpp/session_types.h
+++ b/ash/public/cpp/session_types.h
@@ -23,6 +23,12 @@ enum class AddUserSessionPolicy {
   ERROR_MAXIMUM_USERS_REACHED,
 };
 
+// Defines the cycle direction for |CycleActiveUser|.
+enum class CycleUser {

[James Cook, 2017/03/02 00:13:34]

I think this would be clearer as:

enum class CycleUserDirection {
  NEXT,
  PREVIOUS,
}

or something that has "direction" in it.

Then all the params/local variables could be called "direction".

[xiyuan, 2017/03/02 21:27:45]

Done.

+  CYCLE_TO_NEXT_USER = 0,  // Cycle to the next user.
+  CYCLE_TO_PREVIOUS_USER,  // Cycle to the previous user.
+};
+
 }  // namespace ash
 
 #endif  // ASH_PUBLIC_CPP_SESSION_TYPES_H_