Validate custom pointer icons aren't null.

Bug: 33853287
Test: cts
Change-Id: I844a9aec6e37e306a77eee0644a774f6470cf5df
diff --git a/services/core/java/com/android/server/input/InputManagerService.java b/services/core/java/com/android/server/input/InputManagerService.java
index 87f4030..fbb39384 100644
--- a/services/core/java/com/android/server/input/InputManagerService.java
+++ b/services/core/java/com/android/server/input/InputManagerService.java
@@ -25,6 +25,7 @@
 import com.android.internal.inputmethod.InputMethodSubtypeHandle;
 import com.android.internal.os.SomeArgs;
 import com.android.internal.R;
+import com.android.internal.util.Preconditions;
 import com.android.internal.util.XmlUtils;
 import com.android.server.DisplayThread;
 import com.android.server.LocalServices;
@@ -1700,6 +1701,7 @@
     // Binder call
     @Override
     public void setCustomPointerIcon(PointerIcon icon) {
+        Preconditions.checkNotNull(icon);
         nativeSetCustomPointerIcon(mPtr, icon);
     }