Add base::FeatureParam<> struct

components/ntp_snippets/sessions/foreign_sessions_suggestions_provider.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/sessions/foreign_sessions_suggestions_provider.h"
 
 #include <algorithm>
 #include <map>
 #include <tuple>
 #include <utility>
 
 #include "base/strings/string_piece.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "components/ntp_snippets/category.h"
 #include "components/ntp_snippets/category_info.h"
 #include "components/ntp_snippets/content_suggestion.h"
 #include "components/ntp_snippets/features.h"
 #include "components/ntp_snippets/pref_names.h"
 #include "components/ntp_snippets/pref_util.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/sessions/core/session_types.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/sync_sessions/synced_session.h"
-#include "components/variations/variations_associated_data.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/image/image.h"
 #include "url/gurl.h"
 
 using base::Time;
 using base::TimeDelta;
 using sessions::SerializedNavigationEntry;
 using sessions::SessionTab;
 using sessions::SessionWindow;
 using sync_sessions::SyncedSessionWindow;
 using sync_sessions::SyncedSession;
 
 using DismissedFilter = base::Callback<bool(const std::string& id)>;
 
 namespace ntp_snippets {
 namespace {
 
-const int kMaxForeignTabsTotal = 10;
-const int kMaxForeignTabsPerDevice = 3;
-const int kMaxForeignTabAgeInMinutes = 180;
-
-const char* kMaxForeignTabsTotalParamName = "max_foreign_tabs_total";
-const char* kMaxForeignTabsPerDeviceParamName = "max_foreign_tabs_per_device";
-const char* kMaxForeignTabAgeInMinutesParamName =
-    "max_foreign_tabs_age_in_minutes";
-
-int GetMaxForeignTabsTotal() {
-  return variations::GetVariationParamByFeatureAsInt(
-      ntp_snippets::kForeignSessionsSuggestionsFeature,
-      kMaxForeignTabsTotalParamName, kMaxForeignTabsTotal);
-}
-
-int GetMaxForeignTabsPerDevice() {
-  return variations::GetVariationParamByFeatureAsInt(
-      ntp_snippets::kForeignSessionsSuggestionsFeature,
-      kMaxForeignTabsPerDeviceParamName, kMaxForeignTabsPerDevice);
-}
+constexpr base::FeatureParam<int> kMaxForeignTabsTotalParam{
+    &kForeignSessionsSuggestionsFeature, "max_foreign_tabs_total", 10};
+constexpr base::FeatureParam<int> kMaxForeignTabsPerDeviceParam{
+    &kForeignSessionsSuggestionsFeature, "max_foreign_tabs_per_device", 3};
+constexpr base::FeatureParam<int> kMaxForeignTabAgeInMinutesParam{
+    &kForeignSessionsSuggestionsFeature, "max_foreign_tabs_age_in_minutes",
+    180};
 
 TimeDelta GetMaxForeignTabAge() {
-  return TimeDelta::FromMinutes(variations::GetVariationParamByFeatureAsInt(
-      ntp_snippets::kForeignSessionsSuggestionsFeature,
-      kMaxForeignTabAgeInMinutesParamName, kMaxForeignTabAgeInMinutes));
+  return TimeDelta::FromMinutes(kMaxForeignTabAgeInMinutesParam.Get());
 }
 
 // This filter does two things. Most importantly it lets through only ids that
 // have not been dismissed. The other responsibility this class has is it tracks
 // all of the ids that fly past it, and it will save the intersection of
 // initially dismissed ids, and seen ids. This will aggressively prune any
 // dismissal that is not currently blocking a recent tab.
 class PrefsPruningDismissedItemFilter {
  public:
   explicit PrefsPruningDismissedItemFilter(PrefService* pref_service)
@@ skipping 233 matching lines @@
                                         category_status_);
   }
 
   // observer()->OnNewSuggestions must be called even when we have no
   // suggestions to remove previous suggestions that are now filtered out.
   observer()->OnNewSuggestions(this, provided_category_, BuildSuggestions());
 }
 
 std::vector<ContentSuggestion>
 ForeignSessionsSuggestionsProvider::BuildSuggestions() {
-  const int max_foreign_tabs_total = GetMaxForeignTabsTotal();
-  const int max_foreign_tabs_per_device = GetMaxForeignTabsPerDevice();
+  const int max_foreign_tabs_total = kMaxForeignTabsTotalParam.Get();
+  const int max_foreign_tabs_per_device = kMaxForeignTabsPerDeviceParam.Get();
 
   PrefsPruningDismissedItemFilter filter(pref_service_);
   std::vector<SessionData> suggestion_candidates =
       GetSuggestionCandidates(filter.ToCallback());
   // This sorts by recency so that we keep the most recent entries and they
   // appear as suggestions in reverse chronological order.
   std::sort(suggestion_candidates.begin(), suggestion_candidates.end());
 
   std::vector<ContentSuggestion> suggestions;
   std::set<std::string> included_urls;
@@ skipping 63 matching lines @@
                                data.navigation->virtual_url().spec(),
                                data.navigation->virtual_url());
   suggestion.set_title(data.navigation->title());
   suggestion.set_publish_date(data.tab->timestamp);
   suggestion.set_publisher_name(
       base::UTF8ToUTF16(data.navigation->virtual_url().host()));
   return suggestion;
 }
 
 }  // namespace ntp_snippets