Make the drag input window fullscreen touchable again

Having it non-touchable was making it possible to e.g.
touch buttons and launch new activities out from under
an in-flight drag operation.

Bug 3370698

Change-Id: I46fe70a8fe8fbaa5cca48f6bb478ed7ded1f1cc3
diff --git a/services/java/com/android/server/WindowManagerService.java b/services/java/com/android/server/WindowManagerService.java
index b7ff64d..2af291d 100644
--- a/services/java/com/android/server/WindowManagerService.java
+++ b/services/java/com/android/server/WindowManagerService.java
@@ -5869,7 +5869,7 @@
             final InputWindow inputWindow = windowList.add();
             inputWindow.inputChannel = mDragState.mServerChannel;
             inputWindow.name = "drag";
-            inputWindow.layoutParamsFlags = WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
+            inputWindow.layoutParamsFlags = 0;
             inputWindow.layoutParamsType = WindowManager.LayoutParams.TYPE_DRAG;
             inputWindow.dispatchingTimeoutNanos = DEFAULT_INPUT_DISPATCHING_TIMEOUT_NANOS;
             inputWindow.visible = true;