Use EnablePlayStoreAppSearch feature flag.

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

Index: chrome/browser/ui/app_list/search/search_controller_factory.cc
diff --git a/chrome/browser/ui/app_list/search/search_controller_factory.cc b/chrome/browser/ui/app_list/search/search_controller_factory.cc
index dfa37ec648e4876edff6a48dd28ffcae9b56a110..ab3a5226230892b7122c5c1dbdbf6fb322b7c19f 100644
--- a/chrome/browser/ui/app_list/search/search_controller_factory.cc
+++ b/chrome/browser/ui/app_list/search/search_controller_factory.cc
@@ -121,11 +121,14 @@ std::unique_ptr<SearchController> CreateSearchController(
   }
 
 #if defined(OS_CHROMEOS)
-  size_t playstore_api_group_id =
-      controller->AddGroup(kMaxPlayStoreResults, 1.0);
-  controller->AddProvider(playstore_api_group_id,
-                          base::MakeUnique<ArcPlayStoreSearchProvider>(
-                              kMaxPlayStoreResults, profile, list_controller));
+  if (features::IsPlayStoreAppSearchEnabled()) {
+    size_t playstore_api_group_id =
+        controller->AddGroup(kMaxPlayStoreResults, 1.0);
+    controller->AddProvider(
+        playstore_api_group_id,
+        base::MakeUnique<ArcPlayStoreSearchProvider>(kMaxPlayStoreResults,
+                                                     profile, list_controller));
+  }
 #endif
   return controller;
 }