[reference - do not submit] Always create four pools in TaskSchedulerImpl.

content/public/browser/content_browser_client.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 32 matching lines @@
 
 #if defined(OS_POSIX)
 #include "content/public/browser/file_descriptor_info.h"
 #endif
 
 class GURL;
 
 namespace base {
 class CommandLine;
 class FilePath;
-class SchedulerWorkerPoolParams;
 }
 
 namespace gfx {
 class ImageSkia;
 }
 
 namespace gpu {
 class GpuChannelEstablishFactory;
 }
 
@@ skipping 742 matching lines @@
   // embedder, for the |source| that lives in the render frame represented
   // by |render_frame_host|. This may be called multiple times if there is more
   // than one source candidate in the same render frame.
   virtual void CreateMediaRemoter(RenderFrameHost* render_frame_host,
                                   media::mojom::RemotingSourcePtr source,
                                   media::mojom::RemoterRequest request) {}
 
   // Returns the RapporService from the browser process.
   virtual ::rappor::RapporService* GetRapporService();
 
-  // Provides parameters for initializing the global task scheduler. If
-  // |params_vector| is empty, default parameters are used.
-  virtual void GetTaskSchedulerInitializationParams(
-      std::vector<base::SchedulerWorkerPoolParams>* params_vector,
-      base::TaskScheduler::WorkerPoolIndexForTraitsCallback*
-          index_to_traits_callback) {}
+  // Provides parameters for initializing the global task scheduler. Default
+  // params are used if this returns nullptr.
+  virtual std::unique_ptr<base::TaskSchedulerInitParams>
+  GetTaskSchedulerInitParams();
 
   // Performs any necessary PostTask API redirection to the task scheduler.
   virtual void PerformExperimentalTaskSchedulerRedirections() {}
 
   // Returns true if the DOMStorageTaskRunner should be redirected to the task
   // scheduler.
   virtual bool ShouldRedirectDOMStorageTaskRunner();
 
   // If this returns true, all BrowserThreads (but UI/IO) that support it on
   // this platform will experimentally be redirected to TaskScheduler.
   virtual bool RedirectNonUINonIOBrowserThreadsToTaskScheduler();
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_