Generalize the usage of referrer chain

chrome/browser/safe_browsing/safe_browsing_service.h

 // 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.
 //
 // The Safe Browsing service is responsible for downloading anti-phishing and
 // anti-malware tables and checking urls against them.
 
 #ifndef CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_SERVICE_H_
 #define CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_SERVICE_H_
 
@@ skipping 320 matching lines @@
   base::CallbackList<void(void)> shutdown_callback_list_;
 
   // The UI manager handles showing interstitials.  Accessed on both UI and IO
   // thread.
   scoped_refptr<SafeBrowsingUIManager> ui_manager_;
 
   // The database manager handles the database and download logic.  Accessed on
   // both UI and IO thread.
   scoped_refptr<SafeBrowsingDatabaseManager> database_manager_;
 
-  // The navigation observer manager handles download attribution.
+  // The navigation observer manager handles attribution of safe browsing
+  // events.
   scoped_refptr<SafeBrowsingNavigationObserverManager>
-  navigation_observer_manager_;
+      navigation_observer_manager_;
 
   // The password protection service detects and handles password related
   // incidents.
   std::unique_ptr<PasswordProtectionService> password_protection_service_;
 
   DISALLOW_COPY_AND_ASSIGN(SafeBrowsingService);
 };
 
 // Factory for creating SafeBrowsingService.  Useful for tests.
 class SafeBrowsingServiceFactory {
  public:
   SafeBrowsingServiceFactory() { }
   virtual ~SafeBrowsingServiceFactory() { }
   virtual SafeBrowsingService* CreateSafeBrowsingService() = 0;
  private:
   DISALLOW_COPY_AND_ASSIGN(SafeBrowsingServiceFactory);
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_SERVICE_H_