Don't check URLs against Safe Browsing if not supported.

chrome/browser/safe_browsing/remote_database_manager.h

 // Copyright 2015 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.
 //
 // Implementation of the SafeBrowsingDatabaseManager that sends URLs
 // via IPC to a database that chromium doesn't manage locally.
 
 #ifndef CHROME_BROWSER_SAFE_BROWSING_REMOTE_DATABASE_MANAGER_H_
 #define CHROME_BROWSER_SAFE_BROWSING_REMOTE_DATABASE_MANAGER_H_
 
@@ skipping 11 matching lines @@
 class RemoteSafeBrowsingDatabaseManager : public SafeBrowsingDatabaseManager {
  public:
   // Construct RemoteSafeBrowsingDatabaseManager.
   // Must be initialized by calling StartOnIOThread() before using.
   RemoteSafeBrowsingDatabaseManager();
 
   //
   // SafeBrowsingDatabaseManager implementation
   //
 
+  bool IsSupported() const override;
   bool CanCheckUrl(const GURL& url) const override;
   bool download_protection_enabled() const override;
   bool CheckBrowseUrl(const GURL& url, Client* client) override;
   void CancelCheck(Client* client) override;
   void StartOnIOThread() override;
   void StopOnIOThread(bool shutdown) override;
 
   // These will fail with DCHECK() since their functionality isn't implemented.
   // We may later add support for a subset of them.
   bool CheckDownloadUrl(const std::vector<GURL>& url_chain,
@@ skipping 18 matching lines @@
 
   // Requests currently outstanding.  This owns the ptrs.
   std::vector<ClientRequest*> current_requests_;
   bool enabled_;
 
   friend class base::RefCountedThreadSafe<RemoteSafeBrowsingDatabaseManager>;
   DISALLOW_COPY_AND_ASSIGN(RemoteSafeBrowsingDatabaseManager);
 };  // class RemoteSafeBrowsingDatabaseManager
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_REMOTE_DATABASE_MANAGER_H_