Add a WorkerScheduler and a WebThreadImplForWorker

content/child/scheduler/webthread_impl_for_worker.cc

+// Copyright 2015 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 "content/child/scheduler/webthread_impl_for_worker.h"
+
+#include "base/bind.h"
+#include "cc/base/completion_event.h"
+#include "content/child/scheduler/scheduler_message_loop_delegate.h"
+#include "content/child/scheduler/worker_scheduler_impl.h"
+#include "third_party/WebKit/public/platform/WebTraceLocation.h"
+
+namespace content {
+
+WebThreadImplForWorker::WebThreadImplForWorker(const char* name)
+    : thread_(new base::Thread(name)) {
+  thread_->Start();
+
+  cc::CompletionEvent completion;

[kinuko, 2015/04/02 13:03:08]

Drive-by question: I'm a bit surprised to see cc code here. It looks like we can
easily replace this with base::WaitableEvent, and to me it feels more natural.
Do you have a particular reason to use this class here?

[alex clarke (OOO till 29th), 2015/04/02 15:19:28]

No particular reason. Changed.

+  thread_->message_loop()->PostTask(
+      FROM_HERE, base::Bind(&WebThreadImplForWorker::InitOnThread,
+                            base::Unretained(this), &completion));
+  completion.Wait();
+}
+
+WebThreadImplForWorker::~WebThreadImplForWorker() {
+  cc::CompletionEvent completion;
+  thread_->message_loop()->PostTask(
+      FROM_HERE, base::Bind(&WebThreadImplForWorker::ShutDownOnThread,
+                            base::Unretained(this), &completion));
+  completion.Wait();
+
+  thread_->Stop();
+}
+
+void WebThreadImplForWorker::InitOnThread(cc::CompletionEvent* completion) {
+  worker_scheduler_ = WorkerScheduler::Create(thread_->message_loop());
+  worker_scheduler_->Init();
+  task_runner_ = worker_scheduler_->DefaultTaskRunner();
+  idle_task_runner_ = worker_scheduler_->IdleTaskRunner();
+  completion->Signal();
+}
+
+void WebThreadImplForWorker::ShutDownOnThread(cc::CompletionEvent* completion) {
+  task_runner_ = NULL;

[Sami, 2015/04/02 10:19:46]

nullptr (here and below)

[alex clarke (OOO till 29th), 2015/04/02 15:19:28]

Done.

+  idle_task_runner_ = NULL;
+  worker_scheduler_.reset(nullptr);
+  completion->Signal();
+}
+
+blink::PlatformThreadId WebThreadImplForWorker::threadId() const {
+  return thread_->thread_id();
+}
+
+base::MessageLoop* WebThreadImplForWorker::MessageLoop() const {
+  // As per WebThreadImpl::MessageLoop()
+  return nullptr;
+}
+
+base::SingleThreadTaskRunner* WebThreadImplForWorker::TaskRunner() const {
+  return task_runner_.get();
+}
+
+SingleThreadIdleTaskRunner* WebThreadImplForWorker::IdleTaskRunner() const {
+  return idle_task_runner_.get();
+}
+
+void WebThreadImplForWorker::AddTaskObserverInternal(
+    base::MessageLoop::TaskObserver* observer) {
+  worker_scheduler_->AddTaskObserver(observer);
+}
+
+void WebThreadImplForWorker::RemoveTaskObserverInternal(
+    base::MessageLoop::TaskObserver* observer) {
+  worker_scheduler_->RemoveTaskObserver(observer);
+}
+
+}  // namespace content