Switch Safe Browsing's metadata from string to struct.

components/safe_browsing_db/database_manager.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 COMPONENTS_SAFE_BROWSING_DB_DATABASE_MANAGER_H_
 #define COMPONENTS_SAFE_BROWSING_DB_DATABASE_MANAGER_H_
 
@@ skipping 25 matching lines @@
   // Callers requesting a result should derive from this class.
   // The destructor should call db_manager->CancelCheck(client) if a
   // request is still pending.
   class Client {
    public:
     virtual ~Client() {}
 
     // Called when the result of checking a browse URL is known.
     virtual void OnCheckBrowseUrlResult(const GURL& url,
                                         SBThreatType threat_type,
-                                        const std::string& metadata) {}
+                                        const ThreatMetadata& metadata) {}
 
     // Called when the result of checking a download URL is known.
     virtual void OnCheckDownloadUrlResult(const std::vector<GURL>& url_chain,
                                           SBThreatType threat_type) {}
 
     // Called when the result of checking a set of extensions is known.
     virtual void OnCheckExtensionsResult(
         const std::set<std::string>& threats) {}
 
     // Called when the result of checking the API blacklist is known.
@@ skipping 118 matching lines @@
 
   friend class base::RefCountedThreadSafe<SafeBrowsingDatabaseManager>;
 
   // Created and destroyed via StartonIOThread/StopOnIOThread.
   V4GetHashProtocolManager* v4_get_hash_protocol_manager_;
 };  // class SafeBrowsingDatabaseManager
 
 }  // namespace safe_browsing
 
 #endif  // COMPONENTS_SAFE_BROWSING_DB_DATABASE_MANAGER_H_