Redirect the MessageLoop's task runner to the renderer scheduler

components/scheduler/child/nestable_task_runner_for_test.cc

Index: components/scheduler/child/nestable_task_runner_for_test.cc
diff --git a/components/scheduler/child/nestable_task_runner_for_test.cc b/components/scheduler/child/nestable_task_runner_for_test.cc
index 5bcfde816db70f3286bea0b98629a55396cab686..74357f2aecc57a6ae6aa9301c9eb7d5f1dbc5c52 100644
--- a/components/scheduler/child/nestable_task_runner_for_test.cc
+++ b/components/scheduler/child/nestable_task_runner_for_test.cc
@@ -34,6 +34,11 @@ void NestableTaskRunnerForTest::WrapTask(
                     WillProcessTask(*wrapped_task));
 }
 
+void NestableTaskRunnerForTest::SetDefaultTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
+  default_task_runner_ = task_runner.Pass();
+}
+
 bool NestableTaskRunnerForTest::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,