scheduler: Move the Blink scheduler into Blink

components/scheduler/base/work_queue.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 "components/scheduler/base/work_queue.h"
-
-#include "components/scheduler/base/work_queue_sets.h"
-
-namespace scheduler {
-namespace internal {
-
-WorkQueue::WorkQueue(TaskQueueImpl* task_queue, const char* name)
-    : work_queue_sets_(nullptr),
-      task_queue_(task_queue),
-      work_queue_set_index_(0),
-      name_(name) {}
-
-void WorkQueue::AsValueInto(base::trace_event::TracedValue* state) const {
-  // Remove const to search |work_queue_| in the destructive manner. Restore the
-  // content from |visited| later.
-  std::queue<TaskQueueImpl::Task>* mutable_queue =
-      const_cast<std::queue<TaskQueueImpl::Task>*>(&work_queue_);
-  std::queue<TaskQueueImpl::Task> visited;
-  while (!mutable_queue->empty()) {
-    TaskQueueImpl::TaskAsValueInto(mutable_queue->front(), state);
-    visited.push(std::move(mutable_queue->front()));
-    mutable_queue->pop();
-  }
-  *mutable_queue = std::move(visited);
-}
-
-WorkQueue::~WorkQueue() {
-  DCHECK(!work_queue_sets_) << task_queue_ ->GetName() << " : "
-      << work_queue_sets_->name() << " : " << name_;
-}
-
-const TaskQueueImpl::Task* WorkQueue::GetFrontTask() const {
-  if (work_queue_.empty())
-    return nullptr;
-  return &work_queue_.front();
-}
-
-bool WorkQueue::GetFrontTaskEnqueueOrder(EnqueueOrder* enqueue_order) const {
-  if (work_queue_.empty())
-    return false;
-  *enqueue_order = work_queue_.front().enqueue_order();
-  return true;
-}
-
-void WorkQueue::Push(TaskQueueImpl::Task task) {
-  bool was_empty = work_queue_.empty();
-  work_queue_.push(std::move(task));
-  if (was_empty && work_queue_sets_)
-    work_queue_sets_->OnPushQueue(this);
-}
-
-void WorkQueue::PushAndSetEnqueueOrder(TaskQueueImpl::Task task,
-                                       EnqueueOrder enqueue_order) {
-  bool was_empty = work_queue_.empty();
-  work_queue_.push(std::move(task));
-  work_queue_.back().set_enqueue_order(enqueue_order);
-
-  if (was_empty && work_queue_sets_)
-    work_queue_sets_->OnPushQueue(this);
-}
-
-void WorkQueue::PopTaskForTest() {
-  work_queue_.pop();
-}
-
-void WorkQueue::SwapLocked(std::queue<TaskQueueImpl::Task>& incoming_queue) {
-  std::swap(work_queue_, incoming_queue);
-
-  if (!work_queue_.empty() && work_queue_sets_)
-    work_queue_sets_->OnPushQueue(this);
-  task_queue_->TraceQueueSize(true);
-}
-
-TaskQueueImpl::Task WorkQueue::TakeTaskFromWorkQueue() {
-  DCHECK(work_queue_sets_);
-  DCHECK(!work_queue_.empty());
-  TaskQueueImpl::Task pending_task = std::move(work_queue_.front());
-  work_queue_.pop();
-  work_queue_sets_->OnPopQueue(this);
-  task_queue_->TraceQueueSize(false);
-  return pending_task;
-}
-
-void WorkQueue::AssignToWorkQueueSets(WorkQueueSets* work_queue_sets) {
-  work_queue_sets_ = work_queue_sets;
-}
-
-void WorkQueue::AssignSetIndex(size_t work_queue_set_index) {
-  work_queue_set_index_ = work_queue_set_index;
-}
-
-bool WorkQueue::ShouldRunBefore(const WorkQueue* other_queue) const {
-  DCHECK(!work_queue_.empty());
-  DCHECK(!other_queue->work_queue_.empty());
-  EnqueueOrder enqueue_order = 0;
-  EnqueueOrder other_enqueue_order = 0;
-  bool have_task = GetFrontTaskEnqueueOrder(&enqueue_order);
-  bool have_other_task =
-      other_queue->GetFrontTaskEnqueueOrder(&other_enqueue_order);
-  DCHECK(have_task);
-  DCHECK(have_other_task);
-  return enqueue_order < other_enqueue_order;
-}
-
-}  // namespace internal
-}  // namespace scheduler