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

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SignInPromo.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SignInPromo.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SignInPromo.java
index 2ff220c315aadadc6e7ef1d7cfcc377fc38770bc..1a53583ee4c6258f8f66304d3244231c58cb3b4f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SignInPromo.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/SignInPromo.java
@@ -60,7 +60,7 @@ public class SignInPromo extends OptionalLeaf
 
     @Override
     @ItemViewType
-    public int getItemViewType() {
+    protected int getItemViewType() {
         return ItemViewType.PROMO;
     }
 
@@ -74,13 +74,18 @@ public class SignInPromo extends OptionalLeaf
     }
 
     @Override
-    public void onBindViewHolder(NewTabPageViewHolder holder) {
+    protected void onBindViewHolder(NewTabPageViewHolder holder) {
         assert holder instanceof StatusCardViewHolder;
         ((StatusCardViewHolder) holder).onBindViewHolder(this);
         mImpressionTracker.reset(mImpressionTracker.wasTriggered() ? null : holder.itemView);
     }
 
     @Override
+    protected void visitOptionalItem(NodeVisitor visitor) {
+        visitor.visitSignInPromo();
+    }
+
+    @Override
     @StringRes
     public int getHeader() {
         return R.string.snippets_disabled_generic_prompt;