Revert of Run task queue manager work in batches

content/renderer/scheduler/task_queue_manager.cc

Index: content/renderer/scheduler/task_queue_manager.cc
diff --git a/content/renderer/scheduler/task_queue_manager.cc b/content/renderer/scheduler/task_queue_manager.cc
index 5db247bf7839045110afbfb3a2b051d02c2524fe..07d5e669919d408d9ea126a3d3291f13c0dc4eef 100644
--- a/content/renderer/scheduler/task_queue_manager.cc
+++ b/content/renderer/scheduler/task_queue_manager.cc
@@ -4,18 +4,13 @@
 
 #include "content/renderer/scheduler/task_queue_manager.h"
 
-#include <queue>
-
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
+#include "base/debug/trace_event_argument.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
-#include "cc/test/test_now_source.h"
 #include "content/renderer/scheduler/task_queue_selector.h"
 
-namespace {
-const int64_t kMaxTimeTicks = std::numeric_limits<int64>::max();
-}
-
 namespace content {
 namespace internal {
 
@@ -47,7 +42,7 @@ class TaskQueue : public base::SingleThreadTaskRunner {
   void SetAutoPump(bool auto_pump);
   void PumpQueue();
 
-  bool UpdateWorkQueue(base::TimeTicks* next_pending_delayed_task);
+  bool UpdateWorkQueue();
   base::PendingTask TakeTaskFromWorkQueue();
 
   void WillDeleteTaskQueueManager();
@@ -81,9 +76,6 @@ class TaskQueue : public base::SingleThreadTaskRunner {
   base::TaskQueue incoming_queue_;
   bool auto_pump_;
   const char* name_;
-  std::priority_queue<base::TimeTicks,
-                      std::vector<base::TimeTicks>,
-                      std::greater<base::TimeTicks>> delayed_task_run_times_;
 
   base::TaskQueue work_queue_;
 
@@ -123,8 +115,6 @@ bool TaskQueue::PostDelayedTaskImpl(const tracked_objects::Location& from_here,
   task_queue_manager_->DidQueueTask(&pending_task);
 
   if (delay > base::TimeDelta()) {
-    pending_task.delayed_run_time = task_queue_manager_->Now() + delay;
-    delayed_task_run_times_.push(pending_task.delayed_run_time);
     return task_queue_manager_->PostDelayedTask(
         from_here, Bind(&TaskQueue::EnqueueTask, this, pending_task), delay);
   }
@@ -142,16 +132,12 @@ bool TaskQueue::IsQueueEmpty() const {
   }
 }
 
-bool TaskQueue::UpdateWorkQueue(base::TimeTicks* next_pending_delayed_task) {
+bool TaskQueue::UpdateWorkQueue() {
   if (!work_queue_.empty())
     return true;
 
   {
     base::AutoLock lock(lock_);
-    if (!delayed_task_run_times_.empty()) {
-      *next_pending_delayed_task =
-          std::min(*next_pending_delayed_task, delayed_task_run_times_.top());
-    }
     if (!auto_pump_ || incoming_queue_.empty())
       return false;
     work_queue_.Swap(&incoming_queue_);
@@ -186,14 +172,6 @@ void TaskQueue::EnqueueTaskLocked(const base::PendingTask& pending_task) {
   if (auto_pump_ && incoming_queue_.empty())
     task_queue_manager_->MaybePostDoWorkOnMainRunner();
   incoming_queue_.push(pending_task);
-
-  if (!pending_task.delayed_run_time.is_null()) {
-    // Update the time of the next pending delayed task.
-    while (!delayed_task_run_times_.empty() &&
-           delayed_task_run_times_.top() <= pending_task.delayed_run_time) {
-      delayed_task_run_times_.pop();
-    }
-  }
 }
 
 void TaskQueue::SetAutoPump(bool auto_pump) {
@@ -269,8 +247,6 @@ TaskQueueManager::TaskQueueManager(
     : main_task_runner_(main_task_runner),
       selector_(selector),
       pending_dowork_count_(0),
-      work_batch_size_(1),
-      time_source_(nullptr),
       weak_factory_(this) {
   DCHECK(main_task_runner->RunsTasksOnCurrentThread());
   TRACE_EVENT_OBJECT_CREATED_WITH_ID(
@@ -325,15 +301,14 @@ void TaskQueueManager::PumpQueue(size_t queue_index) {
   queue->PumpQueue();
 }
 
-bool TaskQueueManager::UpdateWorkQueues(
-    base::TimeTicks* next_pending_delayed_task) {
+bool TaskQueueManager::UpdateWorkQueues() {
   // TODO(skyostil): This is not efficient when the number of queues grows very
   // large due to the number of locks taken. Consider optimizing when we get
   // there.
   main_thread_checker_.CalledOnValidThread();
   bool has_work = false;
   for (auto& queue : queues_)
-    has_work |= queue->UpdateWorkQueue(next_pending_delayed_task);
+    has_work |= queue->UpdateWorkQueue();
   return has_work;
 }
 
@@ -359,26 +334,14 @@ void TaskQueueManager::DoWork(bool posted_from_main_thread) {
     DCHECK_GE(pending_dowork_count_, 0);
   }
   main_thread_checker_.CalledOnValidThread();
+  if (!UpdateWorkQueues())
+    return;
 
-  base::TimeTicks next_pending_delayed_task(
-      base::TimeTicks::FromInternalValue(kMaxTimeTicks));
-  for (int i = 0; i < work_batch_size_; i++) {
-    if (!UpdateWorkQueues(&next_pending_delayed_task))
-      return;
-
-    // Interrupt the work batch if we should run the next delayed task.
-    if (i > 0 && next_pending_delayed_task.ToInternalValue() != kMaxTimeTicks &&
-        Now() >= next_pending_delayed_task)
-      return;
-
-    size_t queue_index;
-    if (!SelectWorkQueueToService(&queue_index))
-      return;
-    // Note that this function won't post another call to DoWork if one is
-    // already pending, so it is safe to call it in a loop.
-    MaybePostDoWorkOnMainRunner();
-    ProcessTaskFromWorkQueue(queue_index);
-  }
+  size_t queue_index;
+  if (!SelectWorkQueueToService(&queue_index))
+    return;
+  MaybePostDoWorkOnMainRunner();
+  ProcessTaskFromWorkQueue(queue_index);
 }
 
 bool TaskQueueManager::SelectWorkQueueToService(size_t* out_queue_index) {
@@ -427,22 +390,6 @@ void TaskQueueManager::SetQueueName(size_t queue_index, const char* name) {
   queue->set_name(name);
 }
 
-void TaskQueueManager::SetWorkBatchSize(int work_batch_size) {
-  main_thread_checker_.CalledOnValidThread();
-  DCHECK_GE(work_batch_size, 1);
-  work_batch_size_ = work_batch_size;
-}
-
-void TaskQueueManager::SetTimeSourceForTesting(
-    scoped_refptr<cc::TestNowSource> time_source) {
-  main_thread_checker_.CalledOnValidThread();
-  time_source_ = time_source;
-}
-
-base::TimeTicks TaskQueueManager::Now() const {
-  return UNLIKELY(time_source_) ? time_source_->Now() : base::TimeTicks::Now();
-}
-
 scoped_refptr<base::debug::ConvertableToTraceFormat>
 TaskQueueManager::AsValueWithSelectorResult(bool should_run,
                                             size_t selected_queue) const {