Introduce a Doodle Fetcher for NTP

components/doodle/doodle_fetcher.h

+// Copyright 2017 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_DOODLE_DOODLE_FETCHER_H_
+#define COMPONENTS_DOODLE_DOODLE_FETCHER_H_
+
+#include <memory>
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "url/gurl.h"
+
+namespace base {
+class DictionaryValue;
+class Value;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace doodle {
+
+enum class DoodleState {
+  UNKNOWN,

[Marc Treib, 2017/01/31 09:46:34]

Is this required? Would it ever be returned?

[fhorschig, 2017/01/31 13:59:18]

Removed. It used to be a default value.

+  AVAILABLE,
+  NO_DOODLE,
+  DOWNLOAD_ERROR,
+  PARSING_ERROR
+};
+
+struct DoodleImage {
+  GURL url;
+  int height;
+  int width;

[Marc Treib, 2017/01/31 09:46:34]

Make a ctor that initializes everything. Recent experience shows that
uninitialized variables are Evil :)

[fhorschig, 2017/01/31 13:59:18]

Done.

+  std::string background_color;
+};
+
+struct DoodleConfig {
+  DoodleConfig();
+  ~DoodleConfig();
+  explicit DoodleConfig(DoodleState doodle_state);
+  DoodleConfig(const DoodleConfig& config);
+
+  DoodleState state;
+
+  GURL search_url;
+  GURL fullpage_interactive_url;
+  std::string doodle_type;

[Marc Treib, 2017/01/31 09:46:34]

What's this? Should it be an enum?

[jshneier, 2017/01/31 13:08:26]

It's populated from this enum:

enum DoodleType {
  SIMPLE = 1;
  RANDOM = 2;
  VIDEO = 3;
  INTERACTIVE = 4;
  INLINE_INTERACTIVE = 5;
  SLIDESHOW = 6;
}

[fhorschig, 2017/01/31 13:59:18]

Why not.

+  base::Time time_to_live_ms;  // The passed "int" doesn't fit int32.

[Marc Treib, 2017/01/31 09:46:34]

nit: Remove comment, it doesn't belong here.
Also, "time_to_live" implies it's a TimeDelta. It's actually more of an
"expiry_date".

[fhorschig, 2017/01/31 13:59:18]

Done.

+  DoodleImage large_image;
+};
+
+class DoodleFetcher : public net::URLFetcherDelegate {
+ public:
+  using FinishedCallback =
+      base::Callback<void(const DoodleConfig& doodle_config)>;
+
+  DoodleFetcher(net::URLRequestContextGetter* download_context, GURL base_url);
+
+  ~DoodleFetcher() override;
+
+  void FetchDoodle(const FinishedCallback& callback);
+
+ private:
+  // net::URLFetcherDelegate implementation.
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
+
+  void OnJsonParsed(std::unique_ptr<base::Value> json);
+  void OnJsonParseFailed(const std::string& error_message);
+  void ParseDoodle(std::unique_ptr<base::DictionaryValue> config);
+
+  // Parameter set from constructor.
+  net::URLRequestContextGetter* const download_context_;
+  GURL base_url_;
+
+  FinishedCallback callback_;
+  std::unique_ptr<net::URLFetcher> fetcher_;
+
+  base::WeakPtrFactory<DoodleFetcher> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DoodleFetcher);
+};
+
+extern const char kDoodleConfigUrl[];
+
+}  // namespace doodle
+
+#endif  // COMPONENTS_DOODLE_DOODLE_FETCHER_H_