Check whether qsIcon is null before using it

Bug: 176428921
Test: Unit Tests, Manual Tests
Change-Id: Ic76e9ad4237b1a5bf71d1ee9801c91d0f3b6e476

packages/SystemUI/src/com/android/systemui/qs/tiles/CastTile.java

@@ -274,7 +274,8 @@ public class CastTile extends QSTileImpl<BooleanState> {
                         NetworkController.IconState qsIcon, boolean activityIn, boolean activityOut,
                         String description, boolean isTransient, String statusLabel) {
                     // statusIcon.visible has the connected status information
-                    boolean enabledAndConnected = enabled && qsIcon.visible;
+                    boolean enabledAndConnected =
+                            enabled && (qsIcon == null ? false : qsIcon.visible);
                     if (enabledAndConnected != mWifiConnected) {
                         mWifiConnected = enabledAndConnected;
                         // Hotspot is not connected, so changes here should update