Add provider support for undoUri

* Also added "seq" parameter for undo support in ConversationCursor

Change-Id: I482e4db437826276e4c13c60835259be175f7a4f
diff --git a/src/com/android/mail/providers/UIProvider.java b/src/com/android/mail/providers/UIProvider.java
index 71bd78c..b9f4879 100644
--- a/src/com/android/mail/providers/UIProvider.java
+++ b/src/com/android/mail/providers/UIProvider.java
@@ -604,4 +604,9 @@
         }
         statsUpdater.updateWithAddress(recipients);
     }
+
+    public static final String[] UNDO_PROJECTION = {
+        ConversationColumns.MESSAGE_LIST_URI
+    };
+    public static final int UNDO_MESSAGE_LIST_COLUMN = 0;
 }