1 files changed, 9 insertions, 2 deletions
diff --git a/core/java/android/content/UndoOwner.java b/core/java/android/content/UndoOwner.java
index d0cdc95..9106588 100644
--- a/core/java/android/content/UndoOwner.java
+++ b/core/java/android/content/UndoOwner.java
@@ -23,8 +23,8 @@ package android.content;
  */
 public class UndoOwner {
     final String mTag;
+    final UndoManager mManager;
 
-    UndoManager mManager;
     Object mData;
     int mOpCount;
 
@@ -32,8 +32,15 @@ public class UndoOwner {
     int mStateSeq;
     int mSavedIdx;
 
-    UndoOwner(String tag) {
+    UndoOwner(String tag, UndoManager manager) {
+        if (tag == null) {
+            throw new NullPointerException("tag can't be null");
+        }
+        if (manager == null) {
+            throw new NullPointerException("manager can't be null");
+        }
         mTag = tag;
+        mManager = manager;
     }
 
     /**