[NTP Snippets] Show a status card when there are no available snippets

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardItemDecoration.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardItemDecoration.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardItemDecoration.java
new file mode 100644
index 0000000000000000000000000000000000000000..1bfee572b2d1e7aa2583d547b4359b5551f3a517
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardItemDecoration.java
@@ -0,0 +1,44 @@
+// 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.content.Context;
+import android.graphics.Rect;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+import org.chromium.chrome.R;
+
+/**
+ * A decorator that places separators between RecyclerView cards.
+ */
+public class CardItemDecoration extends RecyclerView.ItemDecoration {
+    private final int mCardsVerticalSpacing;
+
+    /**
+     * @param context used to retrieve resources.
+     */
+    public CardItemDecoration(Context context) {
+        mCardsVerticalSpacing =
+                context.getResources().getDimensionPixelSize(R.dimen.snippets_vertical_spacing);
+    }
+
+    @Override
+    public void getItemOffsets(
+            Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
+        int childPos = parent.getChildAdapterPosition(view);
+
+        // childPos can be NO_POSITION if the method is called with a view being removed from the
+        // RecyclerView, for example when dismissing an item.
+        if (childPos == RecyclerView.NO_POSITION) return;
+
+        // Add spacing if the current item and the next are cards.
+        if (parent.getChildViewHolder(view) instanceof CardViewHolder
+                && parent.findViewHolderForAdapterPosition(childPos + 1)
+                                instanceof CardViewHolder) {
+            outRect.set(0, 0, 0, mCardsVerticalSpacing);
+        }
+    }
+}