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

chrome/browser/safe_browsing/test_database_manager.cc

 // 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.
 
 #include "chrome/browser/safe_browsing/test_database_manager.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
 
+bool TestSafeBrowsingDatabaseManager::IsSupported() const {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 bool TestSafeBrowsingDatabaseManager::CanCheckUrl(const GURL& url) const {
   NOTIMPLEMENTED();
   return false;
 }
 
 bool TestSafeBrowsingDatabaseManager::download_protection_enabled() const {
   NOTIMPLEMENTED();
   return false;
 }
 
@@ skipping 58 matching lines @@
 
 void TestSafeBrowsingDatabaseManager::CancelCheck(Client* client) {
   NOTIMPLEMENTED();
 }
 
 void TestSafeBrowsingDatabaseManager::StartOnIOThread() {
 }
 
 void TestSafeBrowsingDatabaseManager::StopOnIOThread(bool shutdown) {
 }