NTP: Extract JSON requests from Fetcher.

components/ntp_snippets/remote/ntp_snippets_request_params.h

+// 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_REMOTE_NTP_SNIPPETS_REQUEST_PARAMS_H_
+#define COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_REQUEST_PARAMS_H_
+
+#include <memory>
+#include <set>
+#include <string>
+
+#include "base/callback.h"
+#include "base/optional.h"
+#include "base/values.h"
+#include "components/ntp_snippets/category.h"
+
+namespace ntp_snippets {
+
+// Enumeration listing all possible variants of dealing with personalization.
+enum class Personalization { kPersonal, kNonPersonal, kBoth };
+
+// Contains all parameters for fetching NTPSnippets.
+struct NTPSnippetsRequestParams {
+  NTPSnippetsRequestParams();
+  NTPSnippetsRequestParams(const NTPSnippetsRequestParams&);
+  ~NTPSnippetsRequestParams();
+
+  // BCP 47 language code specifying the user's UI language.
+  std::string language_code;
+
+  // A set of suggestion IDs that should not be returned again.
+  std::set<std::string> excluded_ids;
+
+  // Maximum number of snippets to fetch.
+  int count_to_fetch = 0;
+
+  // Whether this is an interactive request, i.e. triggered by an explicit
+  // user action. Typically, non-interactive requests are subject to a daily
+  // quota.
+  bool interactive_request = false;
+
+  // If set, only return results for this category.
+  base::Optional<Category> exclusive_category;
+};
+
+// Callbacks for JSON parsing, needed because the parsing is platform-

[tschumann, 2016/12/20 10:22:26]

nit: Callbacks for JSON parsing to allow injecting platform-dependent code.

[fhorschig, 2016/12/20 10:30:32]

Done.

+// dependent.
+using SuccessCallback =
+    base::Callback<void(std::unique_ptr<base::Value> result)>;
+using ErrorCallback = base::Callback<void(const std::string& error)>;
+using ParseJSONCallback =
+    base::Callback<void(const std::string& raw_json_string,
+                        const SuccessCallback& success_callback,
+                        const ErrorCallback& error_callback)>;
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_REQUEST_PARAMS_H_