Add ContentSuggestion, ContentSuggestionCategory and ContentSuggestionProviderType

components/ntp_snippets/content_suggestions_provider_type.h

Index: components/ntp_snippets/content_suggestions_provider_type.h
diff --git a/components/ntp_snippets/content_suggestions_provider_type.h b/components/ntp_snippets/content_suggestions_provider_type.h
new file mode 100644
index 0000000000000000000000000000000000000000..9825de8bcd77e33c6ad4c9acb54a4f11d516c405
--- /dev/null
+++ b/components/ntp_snippets/content_suggestions_provider_type.h
@@ -0,0 +1,19 @@
+// 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_CONTENT_SUGGESTIONS_PROVIDER_TYPE_H_
+#define COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_PROVIDER_TYPE_H_
+
+namespace ntp_snippets {
+
+// A type of content suggestion provider. For each of these types, there will be
+// at most one provider instance registered and running. Note that these
+// provider types do not necessarily match the suggestion categories. The
+// provider type is used to identify the source of a suggestion and to direct
+// calls from the UI like discarding back to the right provider.
+enum class ContentSuggestionsProviderType : int { ARTICLES };
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_CONTENT_SUGGESTIONS_PROVIDER_TYPE_H_