[NTP::Push] Add the classes for sending a breaking news subscription request

components/ntp_snippets/breaking_news/subscription_json_request.cc

Index: components/ntp_snippets/breaking_news/subscription_json_request.cc
diff --git a/components/ntp_snippets/breaking_news/subscription_json_request.cc b/components/ntp_snippets/breaking_news/subscription_json_request.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8aec37c1699a4143d442d47fe2bc464ba58b8068
--- /dev/null
+++ b/components/ntp_snippets/breaking_news/subscription_json_request.cc
@@ -0,0 +1,181 @@
+// 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.
+
+#include "components/ntp_snippets/breaking_news/subscription_json_request.h"
+
+#include "base/json/json_writer.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/values.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
+#include "components/variations/net/variations_http_headers.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_context_getter.h"
+
+using net::URLFetcher;
+using net::URLRequestContextGetter;
+using net::HttpRequestHeaders;
+using net::URLRequestStatus;
+
+namespace ntp_snippets {
+
+namespace internal {
+
+SubscriptionJsonRequest::SubscriptionJsonRequest() = default;
+
+SubscriptionJsonRequest::~SubscriptionJsonRequest() {
+  if (!request_completed_callback_.is_null()) {
+    std::move(request_completed_callback_)
+        .Run(ntp_snippets::Status(ntp_snippets::StatusCode::TEMPORARY_ERROR,
+                                  "cancelled"));
+  }
+}
+
+void SubscriptionJsonRequest::Start(CompletedCallback callback) {
+  DCHECK(request_completed_callback_.is_null()) << "Request already running!";
+  request_completed_callback_ = std::move(callback);
+  url_fetcher_->Start();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// URLFetcherDelegate overrides
+void SubscriptionJsonRequest::OnURLFetchComplete(const URLFetcher* source) {
+  DCHECK_EQ(url_fetcher_.get(), source);
+  const URLRequestStatus& status = url_fetcher_->GetStatus();
+  int response = url_fetcher_->GetResponseCode();
+
+  if (!status.is_success()) {
+    std::move(request_completed_callback_)
+        .Run(ntp_snippets::Status(
+            ntp_snippets::StatusCode::TEMPORARY_ERROR,
+            base::StringPrintf("Internal Error: %d", status.error())));
+  } else if (response != net::HTTP_OK) {
+    std::move(request_completed_callback_)
+        .Run(ntp_snippets::Status(
+            ntp_snippets::StatusCode::PERMANENT_ERROR,
+            base::StringPrintf("HTTP Error: %d", response)));
+  } else {
+    std::move(request_completed_callback_)
+        .Run(ntp_snippets::Status(ntp_snippets::StatusCode::SUCCESS,
+                                  std::string()));
+  }
+}
+
+SubscriptionJsonRequest::Builder::Builder() = default;
+SubscriptionJsonRequest::Builder::Builder(SubscriptionJsonRequest::Builder&&) =
+    default;
+SubscriptionJsonRequest::Builder::~Builder() = default;
+
+std::unique_ptr<SubscriptionJsonRequest>
+SubscriptionJsonRequest::Builder::Build() const {
+  DCHECK(!url_.is_empty());
+  DCHECK(url_request_context_getter_);
+  auto request = base::WrapUnique(new SubscriptionJsonRequest());
+
+  std::string body = BuildBody();
+  std::string headers = BuildHeaders();
+  request->url_fetcher_ = BuildURLFetcher(request.get(), headers, body);
+
+  // Log the request for debugging network issues.
+  VLOG(1) << "Sending a subscription request to " << url_ << ":\n"
+          << headers << "\n"
+          << body;
+
+  return request;
+}
+
+SubscriptionJsonRequest::Builder& SubscriptionJsonRequest::Builder::SetToken(
+    const std::string& token) {
+  token_ = token;
+  return *this;
+}
+
+SubscriptionJsonRequest::Builder& SubscriptionJsonRequest::Builder::SetUrl(
+    const GURL& url) {
+  url_ = url;
+  return *this;
+}
+
+SubscriptionJsonRequest::Builder&
+SubscriptionJsonRequest::Builder::SetUrlRequestContextGetter(
+    const scoped_refptr<URLRequestContextGetter>& context_getter) {
+  url_request_context_getter_ = context_getter;
+  return *this;
+}
+
+std::string SubscriptionJsonRequest::Builder::BuildHeaders() const {
+  HttpRequestHeaders headers;
+  headers.SetHeader("Content-Type", "application/json; charset=UTF-8");
+
+  // Add X-Client-Data header with experiment IDs from field trials.
+  // Note: It's OK to pass |is_signed_in| false if it's unknown, as it does
+  // not affect transmission of experiments coming from the variations server.
+  variations::AppendVariationHeaders(url_,
+                                     false,  // incognito
+                                     false,  // uma_enabled
+                                     false,  // is_signed_in
+                                     &headers);
+  return headers.ToString();
+}
+
+std::string SubscriptionJsonRequest::Builder::BuildBody() const {
+  base::DictionaryValue request;
+  request.SetString("token", token_);
+
+  std::string request_json;
+  bool success = base::JSONWriter::Write(request, &request_json);
+  DCHECK(success);
+  return request_json;
+}
+
+std::unique_ptr<URLFetcher> SubscriptionJsonRequest::Builder::BuildURLFetcher(
+    URLFetcherDelegate* delegate,
+    const std::string& headers,
+    const std::string& body) const {
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("gcm_subscription", R"(
+        semantics {
+          sender: "Subscribe for breaking news delivered via GCM push messages"
+          description:
+            "Chromium can receive breaking news via GCM push messages. "
+            "This request suscribes the client to receiving them."
+          trigger:
+            "Subscription takes place only once per profile lifetime. "
+          data:
+            "The subscription token that identifies this Chromium profile."
+          destination: GOOGLE_OWNED_SERVICE
+        }
+        policy {
+          cookies_allowed: false
+          setting:
+            "This feature cannot be disabled by settings now"
+          chrome_policy {
+            NTPContentSuggestionsEnabled {
+              policy_options {mode: MANDATORY}
+              NTPContentSuggestionsEnabled: false
+            }
+          }
+        })");
+  std::unique_ptr<URLFetcher> url_fetcher =
+      URLFetcher::Create(url_, URLFetcher::POST, delegate, traffic_annotation);
+  url_fetcher->SetRequestContext(url_request_context_getter_.get());
+  url_fetcher->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                            net::LOAD_DO_NOT_SAVE_COOKIES);
+  data_use_measurement::DataUseUserData::AttachToFetcher(
+      url_fetcher.get(),
+      data_use_measurement::DataUseUserData::NTP_SNIPPETS_SUGGESTIONS);
+
+  url_fetcher->SetExtraRequestHeaders(headers);
+  url_fetcher->SetUploadData("application/json", body);
+
+  // Fetchers are sometimes cancelled because a network change was detected.
+  url_fetcher->SetAutomaticallyRetryOnNetworkChanges(1);
+  return url_fetcher;
+}
+
+}  // namespace internal
+
+}  // namespace ntp_snippets