[Suggestions] Remove TreeNode.getSuggestionAt() in favor of a visitor.

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/InnerNode.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.Nullable;
 
 import org.chromium.base.Callback;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.ntp.cards.NewTabPageViewHolder.PartialBindCallback;
-import org.chromium.chrome.browser.ntp.snippets.SnippetArticle;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
 /**
  * An inner node in the tree: the root of a subtree, with a list of child nodes.
  */
@@ skipping 54 matching lines @@
     }
 
     @Override
     public void onBindViewHolder(NewTabPageViewHolder holder, int position) {
         int index = getChildIndexForPosition(position);
         mChildren.get(index).onBindViewHolder(
                 holder, position - getStartingOffsetForChildIndex(index));
     }
 
     @Override
-    public SnippetArticle getSuggestionAt(int position) {
-        int index = getChildIndexForPosition(position);
-        return mChildren.get(index).getSuggestionAt(
-                position - getStartingOffsetForChildIndex(index));
-    }
-
-    @Override
     public Set<Integer> getItemDismissalGroup(int position) {
         int index = getChildIndexForPosition(position);
         int offset = getStartingOffsetForChildIndex(index);
         Set<Integer> itemDismissalGroup =
                 getChildren().get(index).getItemDismissalGroup(position - offset);
         return offsetBy(itemDismissalGroup, offset);
     }
 
     @Override
     public void dismissItem(int position, Callback<String> itemRemovedCallback) {
         int index = getChildIndexForPosition(position);
         getChildren().get(index).dismissItem(
                 position - getStartingOffsetForChildIndex(index), itemRemovedCallback);
     }
 
     @Override
+    public void visitItems(NodeVisitor visitor) {
+        for (TreeNode child : getChildren()) {
+            child.visitItems(visitor);
+        }
+    }
+
+    @Override
     public void onItemRangeChanged(
             TreeNode child, int index, int count, @Nullable PartialBindCallback callback) {
         notifyItemRangeChanged(getStartingOffsetForChild(child) + index, count, callback);
     }
 
     @Override
     public void onItemRangeInserted(TreeNode child, int index, int count) {
         notifyItemRangeInserted(getStartingOffsetForChild(child) + index, count);
     }
 
@@ skipping 78 matching lines @@
             return Collections.singleton(set.iterator().next() + offset);
         }
 
         Set<Integer> offsetSet = new HashSet<>();
         for (int value : set) {
             offsetSet.add(value + offset);
         }
         return offsetSet;
     }
 }