[Android NTP] Move dismissing items into the TreeNode interface.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/TreeNode.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/TreeNode.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/TreeNode.java
index 6816a1a46eec15e2304263945bf255a3d6c14dbb..b1cfafaabc2734b71034aad7dcca1408165ba3dd 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/TreeNode.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/TreeNode.java
@@ -4,6 +4,7 @@
 
 package org.chromium.chrome.browser.ntp.cards;
 
+import org.chromium.base.Callback;
 import org.chromium.chrome.browser.ntp.snippets.SnippetArticle;
 
 /**
@@ -50,6 +51,14 @@ interface TreeNode {
     SnippetArticle getSuggestionAt(int position);
 
     /**
+     * Dismiss the item at the given {@code position}.
+     * @param position The position of the item to be dismissed.
+     * @param itemRemovedCallback Should be called with the title of the dismissed item, to announce
+     * it for accessibility purposes.
+     */
+    public void dismissItem(int position, Callback<String> itemRemovedCallback);
+
+    /**
      * The dismiss sibling is an item that should be dismissed at the same time as the provided
      * one. For example, if we want to dismiss a status card that has a More button attached, the
      * button is the card's dismiss sibling. This function returns the adapter position delta to