Three changes.

- Add FOR_EXPORT_ONLY to Data column.
- Make VCardComposer use Contacts instead of RawContacts.
- Make VCardComposer honor FOR_CONTACT_ONLY regardless of
  the intention of any caller, which makes composer unable to
  compose any contact with "is_restricted" flag, which is unseen
  from outside the contacts provider.

Internal Issue number: 2147248, 2143207

core/java/android/provider/ContactsContract.java

@@ -804,6 +804,22 @@ public final class ContactsContract {
          */
         public static final String CONTENT_TYPE = "vnd.android.cursor.dir/data";
 
+        /**
+         * If {@link #FOR_EXPORT_ONLY} is explicitly set to "1", returned Cursor toward
+         * Data.CONTENT_URI contains only exportable data.
+         *
+         * This flag is useful (currently) only for vCard exporter in Contacts app, which
+         * needs to exclude "un-exportable" data from available data to export, while
+         * Contacts app itself has priviledge to access all data including "un-expotable"
+         * ones and providers return all of them regardless of the callers' intention.
+         * <P>Type: INTEGER</p>
+         *
+         * @hide Maybe available only in Eclair and not really ready for public use.
+         * TODO: remove, or implement this feature completely. As of now (Eclair),
+         * we only use this flag in queryEntities(), not query().
+         */
+        public static final String FOR_EXPORT_ONLY = "for_export_only";
+
         /**
          * Build a {@link android.provider.ContactsContract.Contacts#CONTENT_LOOKUP_URI}
          * style {@link Uri} for the parent {@link android.provider.ContactsContract.Contacts}