Use TaskScheduler::InitParams to initialize TaskScheduler in web_main_loop.mm.

ios/chrome/browser/web/chrome_web_client.mm

 // Copyright 2014 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 "ios/chrome/browser/web/chrome_web_client.h"
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/ios/ios_util.h"
 #include "base/mac/bundle_locations.h"
@@ skipping 153 matching lines @@
     web::WebState* web_state,
     int cert_error,
     const net::SSLInfo& info,
     const GURL& request_url,
     bool overridable,
     const base::Callback<void(bool)>& callback) {
   IOSSSLErrorHandler::HandleSSLError(web_state, cert_error, info, request_url,
                                      overridable, callback);
 }
 
-void ChromeWebClient::GetTaskSchedulerInitializationParams(
-    std::vector<base::SchedulerWorkerPoolParams>* params_vector,
-    base::TaskScheduler::WorkerPoolIndexForTraitsCallback*
-        index_to_traits_callback) {
-  DCHECK(params_vector);
-  DCHECK(index_to_traits_callback);
-  // If this call fails, web will fall back to the default params.
-  *params_vector =
-      task_scheduler_util::GetBrowserWorkerPoolParamsFromVariations();
-  *index_to_traits_callback =
-      base::Bind(&task_scheduler_util::BrowserWorkerPoolIndexForTraits);
+std::unique_ptr<base::TaskScheduler::InitParams>
+ChromeWebClient::GetTaskSchedulerInitParams() {
+  return task_scheduler_util::GetBrowserTaskSchedulerInitParamsFromVariations();
 }
 
 void ChromeWebClient::PerformExperimentalTaskSchedulerRedirections() {
   task_scheduler_util::MaybePerformBrowserTaskSchedulerRedirection();
 }