Worker: Introduce per-global-scope task scheduler

third_party/WebKit/Source/platform/scheduler/child/worker_global_scope_scheduler.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "platform/scheduler/child/worker_global_scope_scheduler.h"
+
+#include "platform/scheduler/child/worker_scheduler.h"
+
+namespace blink {
+namespace scheduler {
+
+WorkerGlobalScopeScheduler::WorkerGlobalScopeScheduler(
+    WorkerScheduler* worker_scheduler) {
+  scoped_refptr<TaskQueue> task_queue =
+      worker_scheduler->CreateUnthrottledTaskRunner(
+          TaskQueue::QueueType::UNTHROTTLED);
+  unthrottled_task_runner_ = WebTaskRunnerImpl::Create(std::move(task_queue));
+}
+
+WorkerGlobalScopeScheduler::~WorkerGlobalScopeScheduler() {
+#if DCHECK_IS_ON()
+  DCHECK(is_disposed_);
+#endif
+}
+
+void WorkerGlobalScopeScheduler::Dispose() {
+  unthrottled_task_runner_->GetTaskQueue()->UnregisterTaskQueue();
+#if DCHECK_IS_ON()
+  is_disposed_ = true;
+#endif
+}
+
+}  // namespace scheduler
+}  // namespace blink