Add InterestsFetcher which retrieves a user's interests from the server.

chrome/browser/interests/interests_fetcher.h

Index: chrome/browser/interests/interests_fetcher.h
diff --git a/chrome/browser/interests/interests_fetcher.h b/chrome/browser/interests/interests_fetcher.h
new file mode 100644
index 0000000000000000000000000000000000000000..ac06c961256a088c65fafd8720bd9cd755830e17
--- /dev/null
+++ b/chrome/browser/interests/interests_fetcher.h
@@ -0,0 +1,76 @@
+// Copyright 2015 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 CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_
+#define CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "net/url_request/url_fetcher_factory.h"

[Marc Treib, 2015/09/22 12:02:59]

Not needed anymore

[tache, 2015/09/29 09:33:34]

Done.

+
+FORWARD_DECLARE_TEST(InterestsFetcherTest, DefaultFakeResponse);

[Marc Treib, 2015/09/22 12:02:59]

not needed anymore (test doesn't exist anymore)

[tache, 2015/09/29 09:33:34]

Done.

+
+// Class to asynchronously retrieve the topics of interests for a user.
+// Authentication is done using the user's OAuth access_token.
+//
+// The user of this class is responsible of ensuring that the instance is
+// deleted only after the callback has been called.

[Marc Treib, 2015/09/22 12:02:59]

This sounds like bad things will happen if you delete the InterestsFetcher
before it's done. But that's not actually the case, is it? It will basically
just abort the request (by deleting the URLFetcher), which is fine.

[tache, 2015/09/29 09:33:34]

Done.

+//
+// Example Usage:
+//
+// auto request = make_scoped_ptr(new InterestsFetcher(
+//    "user_access_token",
+//    callback));
+//
+class InterestsFetcher : public net::URLFetcherDelegate {
+ public:
+  struct Interest {
+    std::string name;
+    std::string image_url;
+    double relevance;
+
+    bool operator==(const Interest& interest) const;
+  };
+
+  typedef base::Callback<void(const std::vector<Interest>&)>
+      InterestsCallback;
+
+  InterestsFetcher(net::URLRequestContextGetter* url_request_context,
+                     const std::string& access_token);

[Marc Treib, 2015/09/22 12:02:59]

nit: alignment

[tache, 2015/09/29 09:33:34]

Done.

+
+  void Start(const InterestsCallback& callback);
+
+  ~InterestsFetcher() override;
+
+ private:
+  FRIEND_TEST_ALL_PREFIXES(::InterestsFetcherTest, DefaultFakeResponse);

[Marc Treib, 2015/09/22 12:02:59]

not needed anymore

[tache, 2015/09/29 09:33:34]

Done.

+
+  // net::URLFetcherDelegate implementation.
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
+
+  scoped_ptr<net::URLFetcher> CreateFetcher();
+
+  // parse the json response
+  std::vector<Interest> ExtractInterests(const std::string& response);
+
+  net::URLRequestContextGetter* url_request_context_;
+
+  std::string access_token_;
+
+  InterestsCallback callback_;
+
+  scoped_ptr<net::URLFetcher> fetcher_;
+
+
+  DISALLOW_COPY_AND_ASSIGN(InterestsFetcher);
+};
+
+#endif  // CHROME_BROWSER_INTERESTS_INTERESTS_FETCHER_H_