Merge "Fix CrossAppDragAndDropTests failed" into tm-dev am: 1ae1828729

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18753447

Change-Id: Id2b3b63560738ad2ed57aee74dc80941bff7673d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

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

@@ -342,6 +342,11 @@ class DragDropController {
     }
 
     void reportDropWindow(IBinder token, float x, float y) {
+        if (mDragState == null) {
+            Slog.w(TAG_WM, "Drag state is closed.");
+            return;
+        }
+
         synchronized (mService.mGlobalLock) {
             mDragState.reportDropWindowLock(token, x, y);
         }