Merge "[SB][Location] Synchronize on location callbacks when adding/removing." into main

packages/SystemUI/src/com/android/systemui/statusbar/policy/LocationControllerImpl.java

@@ -40,6 +40,7 @@ import android.os.UserManager;
 import android.provider.DeviceConfig;
 import android.provider.Settings;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 
@@ -361,6 +362,7 @@ public class LocationControllerImpl extends BroadcastReceiver implements Locatio
         private static final int MSG_ADD_CALLBACK = 3;
         private static final int MSG_REMOVE_CALLBACK = 4;
 
+        @GuardedBy("mSettingsChangeCallbacks")
         private final ArrayList<LocationChangeCallback> mSettingsChangeCallbacks =
                 new ArrayList<>();
 
@@ -378,10 +380,14 @@ public class LocationControllerImpl extends BroadcastReceiver implements Locatio
                     locationActiveChanged();
                     break;
                 case MSG_ADD_CALLBACK:
-                    mSettingsChangeCallbacks.add((LocationChangeCallback) msg.obj);
+                    synchronized (mSettingsChangeCallbacks) {
+                        mSettingsChangeCallbacks.add((LocationChangeCallback) msg.obj);
+                    }
                     break;
                 case MSG_REMOVE_CALLBACK:
-                    mSettingsChangeCallbacks.remove((LocationChangeCallback) msg.obj);
+                    synchronized (mSettingsChangeCallbacks) {
+                        mSettingsChangeCallbacks.remove((LocationChangeCallback) msg.obj);
+                    }
                     break;
 
             }