implement "load more" placeholder

app/src/main/java/com/keylesspalace/tusky/util/ViewDataUtils.java

@@ -1,3 +1,18 @@
+/* Copyright 2017 Andrew Dawson
+ *
+ * This file is a part of Tusky.
+ *
+ * This program is free software; you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * Tusky is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
+ * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with Tusky; if not,
+ * see <http://www.gnu.org/licenses>. */
+
 package com.keylesspalace.tusky.util;
 
 import android.arch.core.util.Function;
@@ -19,6 +34,11 @@ public final class ViewDataUtils {
     @Nullable
     public static StatusViewData statusToViewData(@Nullable Status status) {
         if (status == null) return null;
+        if(status.placeholder) {
+            return new StatusViewData.Builder().setId(status.id)
+                    .setPlaceholder(true)
+                    .createStatusViewData();
+        }
         Status visibleStatus = status.reblog == null ? status : status.reblog;
         return new StatusViewData.Builder().setId(status.id)
                 .setAttachments(visibleStatus.attachments)
@@ -61,7 +81,7 @@ public final class ViewDataUtils {
 
     public static NotificationViewData notificationToViewData(Notification notification) {
         return new NotificationViewData(notification.type, notification.id, notification.account,
-                statusToViewData(notification.status));
+                statusToViewData(notification.status), false);
     }
 
     public static List<NotificationViewData> notificationListToViewDataList(