Fixed that the duplicated UserHandle not to be added when it's delivered while booting process

Fixed that the duplicated missed call notification not to be registered
in multi-user environment by not adding the duplicated UserHandle

Bug: 214485291
Test: Reboot the device in multi-user environment when missed call notification is already exist

Signed-off-by: Junyeong Bak <junyeong.bak@samsung.com>
Change-Id: I70a309250eb926d9d9aa888d4aa4fd6579fdfe95
diff --git a/src/com/android/server/telecom/ui/MissedCallNotifierImpl.java b/src/com/android/server/telecom/ui/MissedCallNotifierImpl.java
index 12d3820..8edf158 100644
--- a/src/com/android/server/telecom/ui/MissedCallNotifierImpl.java
+++ b/src/com/android/server/telecom/ui/MissedCallNotifierImpl.java
@@ -68,14 +68,15 @@
 
 import android.telecom.CallerInfo;
 import android.util.ArrayMap;
+import android.util.ArraySet;
 
 import java.lang.Override;
 import java.lang.String;
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * Creates a notification for calls that the user missed (neither answered nor rejected).
@@ -141,7 +142,7 @@
     // Used to track the number of missed calls.
     private final Map<UserHandle, Integer> mMissedCallCounts;
 
-    private List<UserHandle> mUsersToLoadAfterBootComplete = new ArrayList<>();
+    private Set<UserHandle> mUsersToLoadAfterBootComplete = new ArraySet<>();
 
     public MissedCallNotifierImpl(Context context, PhoneAccountRegistrar phoneAccountRegistrar,
             DefaultDialerCache defaultDialerCache,