Worker: Introduce per-global-scope task scheduler

third_party/WebKit/Source/platform/scheduler/child/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/global_scope_scheduler.h"
+
+#include "public/platform/scheduler/child/worker_scheduler.h"
+
+namespace blink {
+namespace scheduler {
+
+GlobalScopeScheduler::GlobalScopeScheduler(WorkerScheduler* worker_scheduler)
+    : worker_scheduler_(worker_scheduler) {
+  unthrottled_task_queue_ = worker_scheduler_->NewUnthrottledTaskRunner(
+      TaskQueue::QueueType::UNTHROTTLED);
+  unthrottled_task_runner_ = WebTaskRunnerImpl::create(unthrottled_task_queue_);
+}
+
+GlobalScopeScheduler::~GlobalScopeScheduler() = default;
+
+void GlobalScopeScheduler::dispose() {
+  if (unthrottled_task_queue_)
+    unthrottled_task_queue_->UnregisterTaskQueue();
+}
+
+}  // namespace scheduler
+}  // namespace blink