content: Add RendererScheduler.

content/renderer/scheduler/single_thread_idle_task_runner.cc

+// Copyright 2014 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/renderer/scheduler/single_thread_idle_task_runner.h"
+
+#include "base/location.h"
+
+namespace content {
+
+SingleThreadIdleTaskRunner::SingleThreadIdleTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+    base::WeakPtr<IdleTaskDeadlineSupplier> deadline_supplier)
+    : task_runner_(task_runner),
+      deadline_supplier_(deadline_supplier) { }
+
+SingleThreadIdleTaskRunner::~SingleThreadIdleTaskRunner() { }
+
+bool SingleThreadIdleTaskRunner::RunsTasksOnCurrentThread() const {
+  return task_runner_->RunsTasksOnCurrentThread();
+}
+
+void SingleThreadIdleTaskRunner::PostIdleTask(
+    const tracked_objects::Location& from_here,
+    const IdleTask& idle_task) {
+  task_runner_->PostTask(FROM_HERE, base::Bind(

[Sami, 2014/10/24 10:46:13]

Please pass the original |from_here| so we don't lose track of which task this
is.

[rmcilroy, 2014/10/24 14:58:29]

Argh, that's what I meant to do - good spot! Done.

+      &SingleThreadIdleTaskRunner::RunTask, base::Unretained(this), idle_task));

[Sami, 2014/10/24 10:46:13]

I guess Unretained shouldn't be used here since the class is refcounted and we
check the weak pointer in the callback.

[rmcilroy, 2014/10/24 14:58:29]

Done.

+}
+
+void SingleThreadIdleTaskRunner::RunTask(IdleTask idle_task) {
+  if (deadline_supplier_) {
+    idle_task.Run(deadline_supplier_->CurrentIdleTaskDeadline());
+  }
+}
+
+}  // namespace content