[Launcher streamlining] Remove boost on search provider groups

This is part of a chain of CLs to simplify how we rank search results.
This removes an unused parameter of search provider groups - the boost -
that increases result scores by a fixed amount.

This used to be used to order the UI containers for apps and non-apps,
but now just makes the scores hard to compare.

Bug: 1028447
Change-Id: I407ca422b645069f4460db15d6bac42c44e4a745
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2374936
Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801682}

chrome/browser/ui/app_list/search/mixer.cc

@@ -45,8 +45,7 @@ bool Mixer::SortData::operator<(const SortData& other) const {
 // Used to group relevant providers together for mixing their results.
 class Mixer::Group {
  public:
-  Group(size_t max_results, double boost)
-      : max_results_(max_results), boost_(boost) {}
+  explicit Group(size_t max_results) : max_results_(max_results) {}
   ~Group() {}
 
   void AddProvider(SearchProvider* provider) {
@@ -62,9 +61,8 @@ class Mixer::Group {
 
         // We cannot rely on providers to give relevance scores in the range
         // [0.0, 1.0]. Clamp to that range.
-        const double relevance =
-            base::ClampToRange(result->relevance(), 0.0, 1.0);
-        results_.emplace_back(result.get(), relevance + boost_);
+        results_.emplace_back(
+            result.get(), base::ClampToRange(result->relevance(), 0.0, 1.0));
       }
     }
 
@@ -80,7 +78,6 @@ class Mixer::Group {
  private:
   typedef std::vector<SearchProvider*> Providers;
   const size_t max_results_;
-  const double boost_;
 
   Providers providers_;  // Not owned.
   SortedResults results_;
@@ -102,8 +99,8 @@ void Mixer::InitializeRankers(Profile* profile,
   }
 }
 
-size_t Mixer::AddGroup(size_t max_results, double boost) {
-  groups_.push_back(std::make_unique<Group>(max_results, boost));
+size_t Mixer::AddGroup(size_t max_results) {
+  groups_.push_back(std::make_unique<Group>(max_results));
   return groups_.size() - 1;
 }
 

chrome/browser/ui/app_list/search/mixer.h

@@ -43,9 +43,8 @@ class Mixer {
   // Adds a new mixer group. A "soft" maximum of |max_results| results will be
   // chosen from this group (if 0, will allow unlimited results from this
   // group). If there aren't enough results from all groups, more than
-  // |max_results| may be chosen from this group. Each result in the group will
-  // have its score increased by |boost|. Returns the group's group_id.
-  size_t AddGroup(size_t max_results, double boost);
+  // |max_results| may be chosen from this group. Returns the group's group_id.
+  size_t AddGroup(size_t max_results);
 
   // Associates a provider with a mixer group.
   void AddProviderToGroup(size_t group_id, SearchProvider* provider);

chrome/browser/ui/app_list/search/search_controller.cc

@@ -143,8 +143,8 @@ void SearchController::InvokeResultAction(ChromeSearchResult* result,
   result->InvokeAction(action_index, event_flags);
 }
 
-size_t SearchController::AddGroup(size_t max_results, double boost) {
-  return mixer_->AddGroup(max_results, boost);
+size_t SearchController::AddGroup(size_t max_results) {
+  return mixer_->AddGroup(max_results);
 }
 
 void SearchController::AddProvider(size_t group_id,

chrome/browser/ui/app_list/search/search_controller.h

@@ -59,7 +59,7 @@ class SearchController {
                           int event_flags);
 
   // Adds a new mixer group. See Mixer::AddGroup.
-  size_t AddGroup(size_t max_results, double boost = 0.0f);
+  size_t AddGroup(size_t max_results);
 
   // Takes ownership of |provider| and associates it with given mixer group.
   void AddProvider(size_t group_id, std::unique_ptr<SearchProvider> provider);

chrome/browser/ui/app_list/search/search_controller_factory.cc

@@ -80,8 +80,6 @@ constexpr size_t kMaxAssistantResults = 1;
 // TODO(wutao): Need UX spec.
 constexpr size_t kMaxSettingsShortcutResults = 6;
 
-constexpr double kAppBoost = 8.0;
-
 }  // namespace
 
 std::unique_ptr<SearchController> CreateSearchController(
@@ -96,16 +94,8 @@ std::unique_ptr<SearchController> CreateSearchController(
   // Set up rankers for search results.
   controller->InitializeRankers();
 
-  // Add mixer groups. There are four main groups: answer card, apps
-  // and omnibox. Each group has a "soft" maximum number of results. However, if
-  // a query turns up very few results, the mixer may take more than this
-  // maximum from a particular group.
-
-  // For the fullscreen app list, apps appear above the answer card, which
-  // appears above other results. Set boosts to |kAppBoost| for apps of all
-  // kinds, 5.0 for answer card, and otherwise 0.0.
-  size_t apps_group_id = controller->AddGroup(kMaxAppsGroupResults, kAppBoost);
-  size_t answer_card_group_id = controller->AddGroup(1, 5.0);
+  size_t apps_group_id = controller->AddGroup(kMaxAppsGroupResults);
+  size_t answer_card_group_id = controller->AddGroup(1);
 
   size_t omnibox_group_id = controller->AddGroup(
       ash::AppListConfig::instance().max_search_result_list_items());
@@ -127,8 +117,7 @@ std::unique_ptr<SearchController> CreateSearchController(
   // The Assistant search provider currently only contributes search results
   // when launcher chip integration is enabled.
   if (chromeos::assistant::features::IsLauncherChipIntegrationEnabled()) {
-    size_t assistant_group_id =
-        controller->AddGroup(kMaxAssistantResults, kAppBoost);
+    size_t assistant_group_id = controller->AddGroup(kMaxAssistantResults);
     controller->AddProvider(assistant_group_id,
                             std::make_unique<AssistantSearchProvider>());
   }
@@ -146,7 +135,7 @@ std::unique_ptr<SearchController> CreateSearchController(
   if (app_list_features::IsAppReinstallZeroStateEnabled() &&
       arc::IsArcAllowedForProfile(profile)) {
     size_t recommended_app_group_id =
-        controller->AddGroup(kMaxAppReinstallSearchResults, kAppBoost);
+        controller->AddGroup(kMaxAppReinstallSearchResults);
     controller->AddProvider(recommended_app_group_id,
                             std::make_unique<ArcAppReinstallSearchProvider>(
                                 profile, kMaxAppReinstallSearchResults));
@@ -155,17 +144,15 @@ std::unique_ptr<SearchController> CreateSearchController(
   if (app_list_features::IsPlayStoreAppSearchEnabled()) {
     // Set same boost as apps group since Play store results are placed
     // with apps.
-    size_t playstore_api_group_id =
-        controller->AddGroup(kMaxPlayStoreResults, kAppBoost);
+    size_t playstore_api_group_id = controller->AddGroup(kMaxPlayStoreResults);
     controller->AddProvider(
         playstore_api_group_id,
         std::make_unique<ArcPlayStoreSearchProvider>(kMaxPlayStoreResults,
                                                      profile, list_controller));
   }
 
   if (app_list_features::IsAppDataSearchEnabled()) {
-    size_t app_data_api_group_id =
-        controller->AddGroup(kMaxAppDataResults, kAppBoost);
+    size_t app_data_api_group_id = controller->AddGroup(kMaxAppDataResults);
     controller->AddProvider(app_data_api_group_id,
                             std::make_unique<ArcAppDataSearchProvider>(
                                 kMaxAppDataResults, list_controller));
@@ -182,8 +169,7 @@ std::unique_ptr<SearchController> CreateSearchController(
   }
 
   if (arc::IsArcAllowedForProfile(profile)) {
-    size_t app_shortcut_group_id =
-        controller->AddGroup(kMaxAppShortcutResults, kAppBoost);
+    size_t app_shortcut_group_id = controller->AddGroup(kMaxAppShortcutResults);
     controller->AddProvider(
         app_shortcut_group_id,
         std::make_unique<ArcAppShortcutsSearchProvider>(

chrome/browser/ui/app_list/search/tests/mixer_unittest.cc

@@ -152,11 +152,9 @@ class MixerTest : public testing::Test {
   void CreateMixer() {
     mixer_ = std::make_unique<Mixer>(model_updater_.get());
 
-    // TODO(warx): when fullscreen app list is default enabled, modify this test
-    // to test answer card/apps group having relevance boost.
-    size_t apps_group_id = mixer_->AddGroup(kMaxAppsGroupResults, 0.0);
-    size_t omnibox_group_id = mixer_->AddGroup(kMaxOmniboxResults, 0.0);
-    size_t playstore_group_id = mixer_->AddGroup(kMaxPlaystoreResults, 0.0);
+    size_t apps_group_id = mixer_->AddGroup(kMaxAppsGroupResults);
+    size_t omnibox_group_id = mixer_->AddGroup(kMaxOmniboxResults);
+    size_t playstore_group_id = mixer_->AddGroup(kMaxPlaystoreResults);
 
     mixer_->AddProviderToGroup(apps_group_id, providers_[0].get());
     mixer_->AddProviderToGroup(omnibox_group_id, providers_[1].get());