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

ios/chrome/browser/web/chrome_web_client.h

Index: ios/chrome/browser/web/chrome_web_client.h
diff --git a/ios/chrome/browser/web/chrome_web_client.h b/ios/chrome/browser/web/chrome_web_client.h
index ae2de1163d27a96fc5d0dea1afbea11a5ad958d9..440a75dda83768e116b92369c279234e75baf507 100644
--- a/ios/chrome/browser/web/chrome_web_client.h
+++ b/ios/chrome/browser/web/chrome_web_client.h
@@ -42,10 +42,8 @@ class ChromeWebClient : public web::WebClient {
       const GURL& request_url,
       bool overridable,
       const base::Callback<void(bool)>& callback) override;
-  void GetTaskSchedulerInitializationParams(
-      std::vector<base::SchedulerWorkerPoolParams>* params_vector,
-      base::TaskScheduler::WorkerPoolIndexForTraitsCallback*
-          index_to_traits_callback) override;
+  std::unique_ptr<base::TaskScheduler::InitParams> GetTaskSchedulerInitParams()
+      override;
   void PerformExperimentalTaskSchedulerRedirections() override;
 
  private: