Add BrowserScheduler field trial to testing config for desktop.

testing/variations/fieldtrial_testing_config.json

Index: testing/variations/fieldtrial_testing_config.json
diff --git a/testing/variations/fieldtrial_testing_config.json b/testing/variations/fieldtrial_testing_config.json
index 36e2269255ea85d12c2ba237458fca41dfb79f9d..cae33b807c91150d43fe266626b7e343c6696599 100644
--- a/testing/variations/fieldtrial_testing_config.json
+++ b/testing/variations/fieldtrial_testing_config.json
@@ -182,6 +182,28 @@
             ]
         }
     ],
+    "BrowserScheduler": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "win"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "params": {
+                        "Background": "3;8;0.1;0;30000",
+                        "BackgroundFileIO": "3;8;0.1;0;30000",
+                        "Foreground": "8;32;0.3;0;30000",
+                        "ForegroundFileIO": "8;32;0.3;0;30000",
+                        "RedirectSequencedWorkerPools": "true"
+                    }
+                }
+            ]
+        }
+    ],
     "CaptivePortalInterstitial": [
         {
             "platforms": [