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

chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SuggestionsSection.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.CallSuper;
 import android.support.annotation.Nullable;
 
 import org.chromium.base.Callback;
@@ skipping 119 matching lines @@
 
         @Override
         public void onBindViewHolder(NewTabPageViewHolder holder, int position) {
             checkIndex(position);
             assert holder instanceof SnippetArticleViewHolder;
             SnippetArticle suggestion = getSuggestionAt(position);
             mSuggestionsRanker.rankSuggestion(suggestion);
             ((SnippetArticleViewHolder) holder).onBindViewHolder(suggestion, mCategoryInfo);
         }
 
-        @Override
         public SnippetArticle getSuggestionAt(int position) {
             return mSuggestions.get(position);
         }
 
         public void clear() {
             int itemCount = mSuggestions.size();
             if (itemCount == 0) return;
 
             mSuggestions.clear();
             notifyItemRangeRemoved(0, itemCount);
@@ skipping 23 matching lines @@
             notifyItemRemoved(position);
             return suggestion;
         }
 
         @Override
         public Iterator<SnippetArticle> iterator() {
             return mSuggestions.iterator();
         }
 
         @Override
+        public void visitItems(NodeVisitor visitor) {
+            for (SnippetArticle suggestion : mSuggestions) {
+                visitor.visitSuggestion(suggestion);
+            }
+        }
+
+        @Override
         public Set<Integer> getItemDismissalGroup(int position) {
             return Collections.singleton(position);
         }
 
         @Override
         public void dismissItem(int position, Callback<String> itemRemovedCallback) {
             checkIndex(position);
             SuggestionsSource suggestionsSource = mUiDelegate.getSuggestionsSource();
             if (suggestionsSource == null) {
                 // It is possible for this method to be called after the NewTabPage has had
@@ skipping 122 matching lines @@
         int i = 0;
         for (SnippetArticle suggestion : mSuggestionsList) {
             if (suggestion.mIdWithinCategory.equals(idWithinCategory)) {
                 mSuggestionsList.remove(i);
                 return;
             }
             i++;
         }
     }
 
-    public boolean hasSuggestions() {
+    private boolean hasSuggestions() {
         return mSuggestionsList.getItemCount() != 0;
     }
 
     public int getSuggestionsCount() {
         return mSuggestionsList.getItemCount();
     }
 
     public boolean isDataStale() {
         return mIsDataStale;
     }
@@ skipping 197 matching lines @@
         public void onSuggestionOfflineIdChanged(SnippetArticle suggestion, @Nullable Long id) {
             mSuggestionsList.updateSuggestionOfflineId(suggestion, id);
         }
 
         @Override
         public Iterable<SnippetArticle> getOfflinableSuggestions() {
             return mSuggestionsList;
         }
     }
 }