Adding a request counter to the snippets fetcher.

components/ntp_snippets/ntp_snippets_fetcher.cc

 // 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.
 
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
 
 #include <stdlib.h>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 140 matching lines @@
       << "Error in translating language code to a locale string: " << error;
   return locale;
 }
 
 }  // namespace
 
 NTPSnippetsFetcher::NTPSnippetsFetcher(
     SigninManagerBase* signin_manager,
     OAuth2TokenService* token_service,
     scoped_refptr<URLRequestContextGetter> url_request_context_getter,
+    PrefService* pref_service,
     const ParseJSONCallback& parse_json_callback,
     bool is_stable_channel)
     : OAuth2TokenService::Consumer("ntp_snippets"),
       signin_manager_(signin_manager),
       token_service_(token_service),
       waiting_for_refresh_token_(false),
       url_request_context_getter_(url_request_context_getter),
       parse_json_callback_(parse_json_callback),
       fetch_url_(GetFetchEndpoint()),
       fetch_api_(UsesChromeContentSuggestionsAPI(fetch_url_)
                      ? CHROME_CONTENT_SUGGESTIONS_API
                      : CHROME_READER_API),
       is_stable_channel_(is_stable_channel),
       tick_clock_(new base::DefaultTickClock()),
+      request_throttler_(
+          pref_service,
+          RequestThrottler::RequestType::CONTENT_SUGGESTION_FETCHER),
       weak_ptr_factory_(this) {
   // Parse the variation parameters and set the defaults if missing.
   std::string personalization = variations::GetVariationParamValue(
       ntp_snippets::kStudyName, kPersonalizationName);
   if (personalization == kPersonalizationNonPersonalString) {
     personalization_ = Personalization::kNonPersonal;
   } else if (personalization == kPersonalizationPersonalString) {
     personalization_ = Personalization::kPersonal;
   } else {
     personalization_ = Personalization::kBoth;
@@ skipping 22 matching lines @@
 }
 
 void NTPSnippetsFetcher::SetCallback(
     const SnippetsAvailableCallback& callback) {
   snippets_available_callback_ = callback;
 }
 
 void NTPSnippetsFetcher::FetchSnippetsFromHosts(
     const std::set<std::string>& hosts,
     const std::string& language_code,
-    int count) {
+    int count,
+    bool force_request) {
+  if (!request_throttler_.DemandQuotaForRequest(force_request))
+    return;
+
   hosts_ = hosts;
   fetch_start_time_ = tick_clock_->NowTicks();
 
   if (UsesHostRestrictions() && hosts_.empty()) {
     FetchFinished(OptionalSnippets(), FetchResult::EMPTY_HOSTS,
                   /*extra_message=*/std::string());
     return;
   }
 
   locale_ = PosixLocaleFromBCP47Language(language_code);
@@ skipping 296 matching lines @@
                       tick_clock_->NowTicks() - fetch_start_time_);
   UMA_HISTOGRAM_ENUMERATION("NewTabPage.Snippets.FetchResult",
                             static_cast<int>(result),
                             static_cast<int>(FetchResult::RESULT_MAX));
 
   if (!snippets_available_callback_.is_null())
     snippets_available_callback_.Run(std::move(snippets));
 }
 
 }  // namespace ntp_snippets