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

chrome/browser/safe_browsing/local_database_manager.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/local_database_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 292 matching lines @@
 
 LocalSafeBrowsingDatabaseManager::~LocalSafeBrowsingDatabaseManager() {
   // The DCHECK is disabled due to crbug.com/438754.
   // DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // We should have already been shut down. If we're still enabled, then the
   // database isn't going to be closed properly, which could lead to corruption.
   DCHECK(!enabled_);
 }
 
+bool LocalSafeBrowsingDatabaseManager::IsSupported() const {
+  return true;
+}
+
 bool LocalSafeBrowsingDatabaseManager::CanCheckUrl(const GURL& url) const {
   return url.SchemeIs(url::kFtpScheme) ||
          url.SchemeIs(url::kHttpScheme) ||
          url.SchemeIs(url::kHttpsScheme);
 }
 
 bool LocalSafeBrowsingDatabaseManager::CheckDownloadUrl(
     const std::vector<GURL>& url_chain,
     Client* client) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
@@ skipping 845 matching lines @@
                  check->weak_ptr_factory_->GetWeakPtr(), check));
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE, base::Bind(&LocalSafeBrowsingDatabaseManager::TimeoutCallback,
                             check->weak_ptr_factory_->GetWeakPtr(), check),
       check_timeout_);
 }
 
 bool LocalSafeBrowsingDatabaseManager::download_protection_enabled() const {
   return enable_download_protection_;
 }