Unify NewTabPageItem and ItemGroup into a single tree-structured interface.

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/AllDismissedItem.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.ntp.cards;
 
 import android.support.annotation.StringRes;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.TextView;
 
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ntp.NewTabPageUma;
 import org.chromium.chrome.browser.ntp.NewTabPageView.NewTabPageManager;
 
 import java.util.Calendar;
 
 /**
  * Displayed when all suggested content and their sections have been dismissed. Provides a button
  * to restore the dismissed sections and load new suggestions from the server.
  */
-public class AllDismissedItem extends SingleItemGroup {
+public class AllDismissedItem extends Leaf {
     @Override
-    public int getType() {
-        return NewTabPageItem.VIEW_TYPE_ALL_DISMISSED;
+    @ItemViewType
+    public int getItemViewType() {
+        return ItemViewType.ALL_DISMISSED;
     }
 
     @Override
     public void onBindViewHolder(NewTabPageViewHolder holder) {
         assert holder instanceof ViewHolder;
         ((ViewHolder) holder).onBindViewHolder();
     }
 
     /**
-     * ViewHolder for an item of type {@link #VIEW_TYPE_ALL_DISMISSED}.
+     * ViewHolder for an item of type {@link ItemViewType#ALL_DISMISSED}.
      */
     public static class ViewHolder extends NewTabPageViewHolder {
         private final TextView mBodyTextView;
 
         public ViewHolder(
                 ViewGroup root, final NewTabPageManager manager, final NewTabPageAdapter adapter) {
             super(LayoutInflater.from(root.getContext())
                             .inflate(R.layout.new_tab_page_all_dismissed, root, false));
             mBodyTextView = (TextView) itemView.findViewById(R.id.body_text);
 
@@ skipping 18 matching lines @@
                 messageId = R.string.ntp_all_dismissed_body_text_morning;
             } else if (hour >= 12 && hour < 17) {
                 messageId = R.string.ntp_all_dismissed_body_text_afternoon;
             } else {
                 messageId = R.string.ntp_all_dismissed_body_text_evening;
             }
             mBodyTextView.setText(messageId);
         }
     }
 }