[Reland] Make canceling Timers fast.

third_party/WebKit/Source/platform/scheduler/base/task_queue_manager_perftest.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/task_queue_manager.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
@@ skipping 20 matching lines @@
         num_tasks_to_post_(0),
         num_tasks_to_run_(0) {}
 
   void SetUp() override {
     if (base::ThreadTicks::IsSupported())
       base::ThreadTicks::WaitUntilInitialized();
   }
 
   void Initialize(size_t num_queues) {
     num_queues_ = num_queues;
-    message_loop_.reset(new base::MessageLoop());
-    run_loop_.reset(new base::RunLoop());
     manager_ = base::MakeUnique<TaskQueueManager>(
         TaskQueueManagerDelegateForTest::Create(
-            message_loop_->task_runner(),
+            base::MessageLoop::current()->task_runner(),
             base::WrapUnique(new base::DefaultTickClock())),
         "fake.category", "fake.category", "fake.category.debug");
     manager_->AddTaskTimeObserver(&test_task_time_observer_);
     for (size_t i = 0; i < num_queues; i++)
       queues_.push_back(manager_->NewTaskQueue(TaskQueue::Spec("test")));
   }
 
   void TestDelayedTask() {
     if (--num_tasks_to_run_ == 0) {
       run_loop_->QuitWhenIdle();
@@ skipping 35 matching lines @@
     num_tasks_to_run_ = num_tasks_to_run;
     TestDelayedTask();
   }
 
   void Benchmark(const std::string& trace, const base::Closure& test_task) {
     base::ThreadTicks start = base::ThreadTicks::Now();
     base::ThreadTicks now;
     unsigned long long num_iterations = 0;
     do {
       test_task.Run();
+      run_loop_.reset(new base::RunLoop());
       run_loop_->Run();
       now = base::ThreadTicks::Now();
       num_iterations++;
     } while (now - start < base::TimeDelta::FromSeconds(5));
     perf_test::PrintResult(
         "task", "", trace,
         (now - start).InMicroseconds() / static_cast<double>(num_iterations),
         "us/run", true);
   }
 
   size_t num_queues_;
   unsigned int max_tasks_in_flight_;
   unsigned int num_tasks_in_flight_;
   unsigned int num_tasks_to_post_;
   unsigned int num_tasks_to_run_;
   std::unique_ptr<TaskQueueManager> manager_;
-  std::unique_ptr<base::MessageLoop> message_loop_;
   std::unique_ptr<base::RunLoop> run_loop_;
   std::vector<scoped_refptr<base::SingleThreadTaskRunner>> queues_;
   // TODO(alexclarke): parameterize so we can measure with and without a
   // TaskTimeObserver.
   TestTaskTimeObserver test_task_time_observer_;
 };
 
 TEST_F(TaskQueueManagerPerfTest, RunTenThousandDelayedTasks_OneQueue) {
   if (!base::ThreadTicks::IsSupported())
     return;
@@ skipping 36 matching lines @@
   Benchmark("run 10000 delayed tasks with eight queues",
             base::Bind(&TaskQueueManagerPerfTest::ResetAndCallTestDelayedTask,
                        base::Unretained(this), 10000));
 }
 
 // TODO(alexclarke): Add additional tests with different mixes of non-delayed vs
 // delayed tasks.
 
 }  // namespace scheduler
 }  // namespace blink