[NTP Snippets] Persist the set of snippets in a pref

components/ntp_snippets/pref_names.cc

Index: components/ntp_snippets/pref_names.cc
diff --git a/components/ntp_snippets/pref_names.cc b/components/ntp_snippets/pref_names.cc
new file mode 100644
index 0000000000000000000000000000000000000000..63085e260de107f71be9218c4175527d29c9f54d
--- /dev/null
+++ b/components/ntp_snippets/pref_names.cc
@@ -0,0 +1,13 @@
+// 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.
+
+#include "components/ntp_snippets/pref_names.h"
+
+namespace ntp_snippets {
+namespace prefs {
+
+const char kSnippets[] = "ntp_snippets.snippets";
+
+}  // namespace prefs
+}  // namespace ntp_snippets