chromium/components/omnibox/browser/omnibox_feature_configs.h

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_FEATURE_CONFIGS_H_
#define COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_FEATURE_CONFIGS_H_

#include "base/feature_list.h"

namespace omnibox_feature_configs {

/*
Finch params aren't cached. Reading the params 100's of times per omnibox
input significantly impacts metrics. Configs cache the params to avoid
regressions. 3 steps:

(1) Declare/define the config:

  // omnibox_feature_configs.h

  struct MyFeature : Config<MyFeature> {
    DECLARE_FEATURE(kMyFeature);

    MyFeature();

    bool enabled;
    int my_param;
  }

  // omnibox_feature_configs.cc

  // static
  BASE_FEATURE(MyFeature::kMyFeature, "OmniboxMyFeature",
               base::FEATURE_DISABLED_BY_DEFAULT);

  MyFeature::MyFeature() {
    enabled = base::FeatureList::IsEnabled(kMyFeature);
    my_param = base::FeatureParam<int>(&kMyFeature, "my_param", 0).Get();
  }


(2) Use the config:

  int x = omnibox_feature_configs::MyFeature::Get().my_param;


(3) Override the config in tests:

  omnibox_feature_configs::ScopedConfigForTesting<
      omnibox_feature_configs::MyFeature> scoped_config;
  scoped_config.Get().enabled = true;
  scoped_config.Get().my_param = 1;
  scoped_config.Reset();
  scoped_config.Get().enabled = true;
  scoped_config.Get().my_param = 2;

  instead of:

  base::test::ScopedFeatureList scoped_feature_list;
  scoped_feature_list_.InitAndEnableFeatureWithParameters(
      omnibox_feature_configs::MyFeature::kMyFeature, {{"my_param", "1"}});
  scoped_feature_list.Reset();
  scoped_feature_list_.InitAndEnableFeatureWithParameters(
      omnibox_feature_configs::MyFeature::kMyFeature, {{"my_param", "2"}});

*/

// A substitute for `BASE_DECLARE_FEATURE` for nesting in structs.
#define DECLARE_FEATURE …

// Base class other configs should inherit from.
template <class T>
class Config { … };

// Util for overriding configs in tests.
template <class T>
class ScopedConfigForTesting : Config<T> { … };

// Add new configs below, ordered alphabetically.

// If enabled, adds recent calc suggestions.
struct CalcProvider : Config<CalcProvider> { … };

// If enabled, allow document provider requests when all other conditions are
// met.
struct DocumentProvider : Config<DocumentProvider> { … };

// If enabled, pretends all matches are allowed to be default. This is very
// blunt, and needs refining before being launch ready. E.g. how does this
// affect transferred matches? This might cause crashes. This can result in
// misleading inline autocompletion; e.g. the bing.com favicon looks like the
// search loupe, so inlined bing results will like DSE search suggestions.
struct ForceAllowedToBeDefault : Config<ForceAllowedToBeDefault> { … };

// If enabled, only suggestions from the keyword mode provider and historical
// keyword mode suggestions will be shown in keyword mode.
struct LimitKeywordModeSuggestions : Config<LimitKeywordModeSuggestions> { … };

// If enabled, NTP Realbox second column will allow displaying contextual and
// trending suggestions.
struct RealboxContextualAndTrendingSuggestions
    : Config<RealboxContextualAndTrendingSuggestions> { … };

// If enabled, omnibox reports the number of zero-prefix suggestions shown in
// the session which ends when autocomplete clears the set of results. The
// current behavior incorrectly reports the number of zero-prefix suggestions in
// the last set of results, which would be 0 for non-zps queries.
struct ReportNumZPSInSession : Config<ReportNumZPSInSession> { … };

// If enabled, uses RichAnswerTemplate instead of SuggestionAnswer to display
// answers.
struct SuggestionAnswerMigration : Config<SuggestionAnswerMigration> { … };

// If enabled, the shortcut provider is more aggressive in scoring.
struct ShortcutBoosting : Config<ShortcutBoosting> { … };

// If enabled, affects autocompleted keywords (e.g. input 'youtu Ispiryan' ->
// match 'Ispiryan - Search YouTube').
// 1) These autocompleted keywords will be scored `score` instead of the default
//    450.
// 2) Autocompletes keyword even when the full keyword is typed ('youtube.com').
//    Otherwise, only incomplete keywords ('youtube.co') are autocompleted.
struct VitalizeAutocompletedKeywords : Config<VitalizeAutocompletedKeywords> { … };

// Do not add new configs here at the bottom by default. They should be ordered
// alphabetically.

#undef DECLARE_FEATURE

}  // namespace omnibox_feature_configs

#endif  // COMPONENTS_OMNIBOX_BROWSER_OMNIBOX_FEATURE_CONFIGS_H_