Control TaskScheduler initialization params in renderers via field trial.

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index 653cf7788df15271ae9279cf110f902e9327115c..61012044bb9b1b5721340cb188018936d31b197b 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -7,6 +7,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/crash_logging.h"
 #include "base/logging.h"
@@ -80,6 +81,7 @@
 #include "components/startup_metric_utils/common/startup_metric.mojom.h"
 #include "components/subresource_filter/content/renderer/ruleset_dealer.h"
 #include "components/subresource_filter/content/renderer/subresource_filter_agent.h"
+#include "components/task_scheduler_util/renderer/initialization.h"
 #include "components/version_info/version_info.h"
 #include "components/visitedlink/renderer/visitedlink_slave.h"
 #include "components/web_cache/renderer/web_cache_impl.h"
@@ -1474,3 +1476,15 @@ GURL ChromeContentRendererClient::OverrideFlashEmbedWithHTML(const GURL& url) {
   RecordYouTubeRewriteUMA(result);
   return corrected_url.ReplaceComponents(r);
 }
+
+void ChromeContentRendererClient::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, content will fall back to the default params.
+  *params_vector = task_scheduler_util::GetRendererWorkerPoolParams();
+  *index_to_traits_callback =
+      base::Bind(&task_scheduler_util::RendererWorkerPoolIndexForTraits);
+}