Control TaskScheduler initialization params in renderers via field trial.

chrome/renderer/chrome_content_renderer_client.h

Index: chrome/renderer/chrome_content_renderer_client.h
diff --git a/chrome/renderer/chrome_content_renderer_client.h b/chrome/renderer/chrome_content_renderer_client.h
index e86b79dd2edae5e564246df91c637133da3400fe..8d584069b63e490e6ed4ea94ddb0df922d275317 100644
--- a/chrome/renderer/chrome_content_renderer_client.h
+++ b/chrome/renderer/chrome_content_renderer_client.h
@@ -182,6 +182,10 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
       const GURL& url) override;
   bool ShouldEnforceWebRTCRoutingPreferences() override;
   GURL OverrideFlashEmbedWithHTML(const GURL& url) override;
+  void GetTaskSchedulerInitializationParams(
+      std::vector<base::SchedulerWorkerPoolParams>* params_vector,
+      base::TaskScheduler::WorkerPoolIndexForTraitsCallback*
+          index_to_traits_callback) override;
 
 #if BUILDFLAG(ENABLE_SPELLCHECK)
   // Sets a new |spellcheck|. Used for testing only.