Use WTF::Deque instead of std::queue in the blink scheduler

third_party/WebKit/Source/platform/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 "platform/scheduler/base/work_queue.h"
 
 #include "platform/scheduler/base/work_queue_sets.h"
 
 namespace blink {
 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),
       fence_(0) {}
 
 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();
+  for (const TaskQueueImpl::Task& task : work_queue_) {
+    TaskQueueImpl::TaskAsValueInto(task, state);
   }
-  *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;
@@ skipping 28 matching lines @@
   return true;
 }
 
 void WorkQueue::Push(TaskQueueImpl::Task task) {
   bool was_empty = work_queue_.empty();
 #ifndef NDEBUG
   DCHECK(task.enqueue_order_set());
 #endif
 
   // Amoritized O(1).
-  work_queue_.push(std::move(task));
+  work_queue_.push_back(std::move(task));
 
   if (!was_empty)
     return;
 
   // If we hit the fence, pretend to WorkQueueSets that we're empty.
   if (work_queue_sets_ && !BlockedByFence())
     work_queue_sets_->OnPushQueue(this);
 }
 
 void WorkQueue::PopTaskForTest() {
   if (work_queue_.empty())
     return;
-  work_queue_.pop();
+  work_queue_.pop_front();
 }
 
-void WorkQueue::SwapLocked(std::queue<TaskQueueImpl::Task>& incoming_queue) {
+void WorkQueue::SwapLocked(WTF::Deque<TaskQueueImpl::Task>& incoming_queue) {
   DCHECK(work_queue_.empty());
-  std::swap(work_queue_, incoming_queue);
+  work_queue_.swap(incoming_queue);
   if (work_queue_.empty())
     return;
   // If we hit the fence, pretend to WorkQueueSets that we're empty.
   if (work_queue_sets_ && !BlockedByFence())
     work_queue_sets_->OnPushQueue(this);
 }
 
 TaskQueueImpl::Task WorkQueue::TakeTaskFromWorkQueue() {
   DCHECK(work_queue_sets_);
   DCHECK(!work_queue_.empty());
 
   // Skip over canceled tasks, except for the last one since we always return
   // something.
   while (work_queue_.size() > 1u && work_queue_.front().task.IsCancelled()) {
-    work_queue_.pop();
+    work_queue_.pop_front();
   }
 
-  TaskQueueImpl::Task pending_task =
-      std::move(const_cast<TaskQueueImpl::Task&>(work_queue_.front()));
-  work_queue_.pop();
+  TaskQueueImpl::Task pending_task = work_queue_.takeFirst();
   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) {
@@ skipping 36 matching lines @@
   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
 }  // namespace blink