Adding a previews IO-thread blacklist

chrome/browser/profiles/profile_impl_io_data.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/profiles/profile_impl_io_data.h"
 
 #include <memory>
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 194 matching lines @@
           profile_->GetRequestContext(), std::move(store),
           BrowserThread::GetTaskRunnerForThread(BrowserThread::UI),
           db_task_runner);
 
   io_data_->set_previews_io_data(base::MakeUnique<previews::PreviewsIOData>(
       BrowserThread::GetTaskRunnerForThread(BrowserThread::UI),
       BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)));
   PreviewsServiceFactory::GetForProfile(profile_)->set_previews_ui_service(
       base::MakeUnique<previews::PreviewsUIService>(
           io_data_->previews_io_data(),
-          BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)));
+          BrowserThread::GetTaskRunnerForThread(BrowserThread::IO), nullptr));
 }
 
 content::ResourceContext*
     ProfileImplIOData::Handle::GetResourceContext() const {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   LazyInitialize();
   return GetResourceContextNoInit();
 }
 
 content::ResourceContext*
@@ skipping 578 matching lines @@
     const base::Closure& completion) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(initialized());
 
   DCHECK(transport_security_state());
   // Completes synchronously.
   transport_security_state()->DeleteAllDynamicDataSince(time);
   DCHECK(http_server_properties_manager_);
   http_server_properties_manager_->Clear(completion);
 }