Check NTP Snippet index before dismissing.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java
index 44dbcdc2cd6df0cc0ebe67dc7f2d25868fa280cf..d2f44674def37b7d3c16c4946fb99444d95636e1 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/cards/CardViewHolder.java
@@ -276,6 +276,9 @@ public class CardViewHolder extends NewTabPageViewHolder {
     protected void dismiss() {
         assert isDismissable();
 
+        // In case the user pressed dismiss on the context menu after swiping to dismiss.
+        if (getAdapterPosition() == RecyclerView.NO_POSITION) return;
+
         // Any changes in the animation here should be reflected also in |updateViewStateForDismiss|
         // and reset in onBindViewHolder.
         AnimatorSet animation = new AnimatorSet();