if requery returns false, throw exception

bug:2894145
Change-Id: Iba36031fae90e53a6c71677e3ec23ba017234407
diff --git a/src/com/android/settings/UserDictionarySettings.java b/src/com/android/settings/UserDictionarySettings.java
index 6ffcb3d..8791e65 100644
--- a/src/com/android/settings/UserDictionarySettings.java
+++ b/src/com/android/settings/UserDictionarySettings.java
@@ -251,7 +251,9 @@
         // TODO: present UI for picking whether to add word to all locales, or current.
         UserDictionary.Words.addWord(this, word.toString(),
                 250, UserDictionary.Words.LOCALE_TYPE_ALL);
-        mCursor.requery();
+        if (!mCursor.requery()) {
+            throw new IllegalStateException("can't requery on already-closed cursor.");
+        }
         mAddedWordAlready = true;
     }