Fix issue #30013670: Phone AP crash when testing VT call

Intent categories may be null.

Change-Id: Ic2e0438460741b264ddbfe77d2a14973f9af7d95
diff --git a/services/core/java/com/android/server/am/AppErrors.java b/services/core/java/com/android/server/am/AppErrors.java
index 49106f4..03843d1 100644
--- a/services/core/java/com/android/server/am/AppErrors.java
+++ b/services/core/java/com/android/server/am/AppErrors.java
@@ -58,6 +58,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Set;
 import java.util.concurrent.Semaphore;
 
 import static com.android.server.Watchdog.NATIVE_STACKS_OF_INTEREST;
@@ -386,8 +387,8 @@
                     } catch (IllegalArgumentException e) {
                         // Hmm, that didn't work, app might have crashed before creating a
                         // recents entry. Let's see if we have a safe-to-restart intent.
-                        if (task.intent.getCategories().contains(
-                                Intent.CATEGORY_LAUNCHER)) {
+                        final Set<String> cats = task.intent.getCategories();
+                        if (cats != null && cats.contains(Intent.CATEGORY_LAUNCHER)) {
                             mService.startActivityInPackage(task.mCallingUid,
                                     task.mCallingPackage, task.intent,
                                     null, null, null, 0, 0,