Clean up DownloadAttribution Finch experiments

chrome/browser/safe_browsing/safe_browsing_service.cc

 // Copyright (c) 2012 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 "chrome/browser/safe_browsing/safe_browsing_service.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 306 matching lines @@
 
   url_request_context_getter_ = new SafeBrowsingURLRequestContextGetter(
       g_browser_process->system_request_context());
 
   ui_manager_ = CreateUIManager();
 
   if (!use_v4_only_) {
     database_manager_ = CreateDatabaseManager();
   }
 
-  if (base::FeatureList::IsEnabled(
-    SafeBrowsingNavigationObserverManager::kDownloadAttribution)) {
-    navigation_observer_manager_ = new SafeBrowsingNavigationObserverManager();
-  }
+  navigation_observer_manager_ = new SafeBrowsingNavigationObserverManager();
 
   services_delegate_->Initialize(v4_enabled_);
   services_delegate_->InitializeCsdService(url_request_context_getter_.get());
 
   // Track profile creation and destruction.
   profiles_registrar_.Add(this, chrome::NOTIFICATION_PROFILE_CREATED,
                           content::NotificationService::AllSources());
   profiles_registrar_.Add(this, chrome::NOTIFICATION_PROFILE_DESTROYED,
                           content::NotificationService::AllSources());
 
@@ skipping 432 matching lines @@
 
 void SafeBrowsingService::RemovePasswordProtectionService(Profile* profile) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(profile);
   auto it = password_protection_service_map_.find(profile);
   if (it != password_protection_service_map_.end())
     password_protection_service_map_.erase(it);
 }
 
 }  // namespace safe_browsing