Add a WorkerScheduler and a WebThreadImplForWorker

content/renderer/scheduler/webthread_impl_for_scheduler.cc

Index: content/renderer/scheduler/webthread_impl_for_scheduler.cc
diff --git a/content/renderer/scheduler/webthread_impl_for_scheduler.cc b/content/renderer/scheduler/webthread_impl_for_scheduler.cc
index b328142846ada43cee212c0b59c25fb2845acbd9..f05864ac61157dd1c598b45ac57d211caada4f93 100644
--- a/content/renderer/scheduler/webthread_impl_for_scheduler.cc
+++ b/content/renderer/scheduler/webthread_impl_for_scheduler.cc
@@ -12,6 +12,7 @@ namespace content {
 WebThreadImplForScheduler::WebThreadImplForScheduler(
     RendererScheduler* scheduler)
     : task_runner_(scheduler->DefaultTaskRunner()),
+      idle_task_runner_(scheduler->IdleTaskRunner()),
       scheduler_(scheduler),
       thread_id_(base::PlatformThread::CurrentId()) {
 }
@@ -32,6 +33,10 @@ base::SingleThreadTaskRunner* WebThreadImplForScheduler::TaskRunner() const {
   return task_runner_.get();
 }
 
+SingleThreadIdleTaskRunner* WebThreadImplForScheduler::IdleTaskRunner() const {
+  return idle_task_runner_.get();
+}
+
 void WebThreadImplForScheduler::AddTaskObserverInternal(
     base::MessageLoop::TaskObserver* observer) {
   scheduler_->AddTaskObserver(observer);