Add ContentSuggestion, ContentSuggestionCategory and ContentSuggestionProviderType

components/ntp_snippets/snippet_category.h

Index: components/ntp_snippets/snippet_category.h
diff --git a/components/ntp_snippets/snippet_category.h b/components/ntp_snippets/snippet_category.h
new file mode 100644
index 0000000000000000000000000000000000000000..c51779282e3429abafaa694192575eb72de04a72
--- /dev/null
+++ b/components/ntp_snippets/snippet_category.h
@@ -0,0 +1,18 @@
+// 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.
+
+#ifndef COMPONENTS_NTP_SNIPPETS_SNIPPET_CATEGORY_TYPE_H_
+#define COMPONENTS_NTP_SNIPPETS_SNIPPET_CATEGORY_TYPE_H_
+
+namespace ntp_snippets {
+
+// The category of a snippet. Note that even though these categories currently
+// match the provider types, a provider type is not limited to provide snippets
+// of a single (fixed) category only. The category is used to determine where
+// to display the snippet.
+enum class SnippetCategory : int { ARTICLE, OFFLINE_PAGE };
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_SNIPPET_CATEGORY_TYPE_H_