[Remote suggestions] Clean up variation params in the request throttler

components/ntp_snippets/remote/request_throttler.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/remote/request_throttler.h"
 
 #include <climits>
 #include <set>
 #include <vector>
 
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
+#include "components/ntp_snippets/features.h"
 #include "components/ntp_snippets/ntp_snippets_constants.h"
 #include "components/ntp_snippets/pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace ntp_snippets {
 
 namespace {
 
@@ skipping 43 matching lines @@
     // RequestCounter::RequestType::CONTENT_SUGGESTION_THUMBNAIL,
     {"SuggestionThumbnailFetcher", prefs::kSnippetThumbnailsRequestCount,
      prefs::kSnippetThumbnailsInteractiveRequestCount,
      prefs::kSnippetThumbnailsRequestsDay, kUnlimitedQuota, kUnlimitedQuota}};
 
 RequestThrottler::RequestThrottler(PrefService* pref_service, RequestType type)
     : pref_service_(pref_service),
       type_info_(kRequestTypeInfo[static_cast<int>(type)]) {
   DCHECK(pref_service);
 
-  std::string quota = variations::GetVariationParamValue(
-      ntp_snippets::kStudyName,
+  std::string quota = variations::GetVariationParamValueByFeature(
+      ntp_snippets::kArticleSuggestionsFeature,
       base::StringPrintf("quota_%s", GetRequestTypeName()));
   if (!base::StringToInt(quota, &quota_)) {
     LOG_IF(WARNING, !quota.empty())
         << "Invalid variation parameter for quota for "
         << GetRequestTypeName();
     quota_ = type_info_.default_quota;
   }
 
-  std::string interactive_quota = variations::GetVariationParamValue(
-      ntp_snippets::kStudyName,
+  std::string interactive_quota = variations::GetVariationParamValueByFeature(
+      ntp_snippets::kArticleSuggestionsFeature,
       base::StringPrintf("interactive_quota_%s", GetRequestTypeName()));
   if (!base::StringToInt(interactive_quota, &interactive_quota_)) {
     LOG_IF(WARNING, !interactive_quota.empty())
         << "Invalid variation parameter for interactive quota for "
         << GetRequestTypeName();
     interactive_quota_ = type_info_.default_interactive_quota;
   }
 
   // Since the histogram names are dynamic, we cannot use the standard macros
   // and we need to lookup the histograms, instead.
@@ skipping 101 matching lines @@
 
 void RequestThrottler::SetDay(int day) {
   pref_service_->SetInteger(type_info_.day_pref, day);
 }
 
 bool RequestThrottler::HasDay() const {
   return pref_service_->HasPrefPath(type_info_.day_pref);
 }
 
 }  // namespace ntp_snippets