Fix NPE from startNewTransition

With shell transition, the token can be null from
WindowOrganizerController#startNewTransition.
E.g. entering split screen.

Bug: 258913831
Test: atest TransitionTests
Change-Id: I77e85c4a340a88056c8188f5da99cf57bf52197e

parent b18b7e97

services/core/java/com/android/server/wm/Transition.java

+2 −1

Original line number	Diff line number	Diff line
		@@ -228,7 +228,8 @@ class Transition implements BLASTSyncEngine.TransactionReadyListener {
		}

		@Nullable
		static Transition fromBinder(@NonNull IBinder token) {
		static Transition fromBinder(@Nullable IBinder token) {
		if (token == null) return null;
		try {
		return ((Token) token).mTransition.get();
		} catch (ClassCastException e) {