Add ContentSuggestion, ContentSuggestionCategory and ContentSuggestionProviderType

components/ntp_snippets/snippet.cc

+// 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/snippet.h"
+
+namespace ntp_snippets {
+
+Snippet::Snippet(const std::string& id,
+                 const SnippetProviderType provider,
+                 const SnippetCategory category)
+    : id_(id), provider_(provider), category_(category), score_(0) {}
+
+Snippet::~Snippet() {}
+
+}  // namespace ntp_snippets