Add ContentSuggestionsCategoryFactory; Store categories as ints

components/ntp_snippets/content_suggestions_category.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/content_suggestions_category.h"
+
+#include "base/logging.h"
+
+namespace ntp_snippets {
+
+ContentSuggestionsCategory::ContentSuggestionsCategory(int id) : id_(id) {}
+
+bool ContentSuggestionsCategory::IsKnownCategory(
+    KnownSuggestionsCategories known_category) const {
+  return id_ == static_cast<int>(known_category);
+}
+
+bool operator==(const ContentSuggestionsCategory& left,
+                const ContentSuggestionsCategory& right) {
+  return left.id() == right.id();
+}
+
+bool operator!=(const ContentSuggestionsCategory& left,
+                const ContentSuggestionsCategory& right) {
+  return !(left == right);
+}
+
+std::ostream& operator<<(std::ostream& os,
+                         const ContentSuggestionsCategory& obj) {
+  os << obj.id();
+  return os;
+}
+
+}  // namespace ntp_snippets