Experiment with redirecting all BrowserThreads (but UI/IO) to TaskScheduler

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 1c7ce3b7eb720ea5a87af2bd1158e39a2da07c23..70336a9ecc5f42699f2b9e3a901911b62a14582c 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -3289,6 +3289,12 @@ ChromeContentBrowserClient::GetMemoryCoordinatorDelegate() {
   return memory::ChromeMemoryCoordinatorDelegate::Create();
 }
 
+bool ChromeContentBrowserClient::
+    RedirectNonUINonIOBrowserThreadsToTaskScheduler() {
+  return variations::GetVariationParamValue(
+             "BrowserScheduler", "RedirectNonUINonIOBrowserThreads") == "true";
+}
+
 #if BUILDFLAG(ENABLE_MEDIA_REMOTING)
 void ChromeContentBrowserClient::CreateMediaRemoter(
     content::RenderFrameHost* render_frame_host,