Don't remove Activities and Tasks until animation done

Just like stacks and displays, activities and tasks need to stick
around until animations have completed.

Change-Id: I54fe8f6855d60cbc3a25cbc6e762defd5ac50bf5
diff --git a/services/core/java/com/android/server/wm/AppWindowToken.java b/services/core/java/com/android/server/wm/AppWindowToken.java
index e98014b..ca4ad8a 100644
--- a/services/core/java/com/android/server/wm/AppWindowToken.java
+++ b/services/core/java/com/android/server/wm/AppWindowToken.java
@@ -105,6 +105,8 @@
     // Input application handle used by the input dispatcher.
     final InputApplicationHandle mInputApplicationHandle;
 
+    boolean mDeferRemoval;
+
     AppWindowToken(WindowManagerService _service, IApplicationToken _token) {
         super(_service, _token.asBinder(),
                 WindowManager.LayoutParams.TYPE_APPLICATION, true);