Adopt a less severe anti-starvation policy for immediate tasks

components/scheduler/base/task_queue_manager_unittest.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 "components/scheduler/base/task_queue_manager.h"
 
 #include "base/location.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/test/simple_test_tick_clock.h"
@@ skipping 1575 matching lines @@
   base::Callback<bool()> should_exit_;
   base::SimpleTestTickClock* now_src_;
 };
 
 bool ShouldExit(QuadraticTask* quadratic_task, LinearTask* linear_task) {
   return quadratic_task->count() == 1000 || linear_task->count() == 1000;
 }
 
 }  // namespace
 
-TEST_F(TaskQueueManagerTest, DelayedTasksDontStarveNonDelayedWork_SameQueue) {
+TEST_F(TaskQueueManagerTest,
+       DelayedTasksDontBadlyStarveNonDelayedWork_SameQueue) {
   Initialize(1u);
 
   QuadraticTask quadratic_delayed_task(
       runners_[0], base::TimeDelta::FromMilliseconds(10), now_src_.get());
   LinearTask linear_immediate_task(runners_[0], base::TimeDelta(),
                                    now_src_.get());
   base::Callback<bool()> should_exit =
       base::Bind(ShouldExit, &quadratic_delayed_task, &linear_immediate_task);
   quadratic_delayed_task.SetShouldExit(should_exit);
   linear_immediate_task.SetShouldExit(should_exit);
 
   quadratic_delayed_task.Run();
   linear_immediate_task.Run();
 
   test_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
   test_task_runner_->RunUntilIdle();
 
   double ratio = static_cast<double>(linear_immediate_task.count()) /
                  static_cast<double>(quadratic_delayed_task.count());
 
-  EXPECT_GT(ratio, 0.9);
+  EXPECT_GT(ratio, 0.333);
   EXPECT_LT(ratio, 1.1);
 }
 
 TEST_F(TaskQueueManagerTest, ImmediateWorkCanStarveDelayedTasks_SameQueue) {
   Initialize(1u);
 
   QuadraticTask quadratic_immediate_task(runners_[0], base::TimeDelta(),
                                          now_src_.get());
   LinearTask linear_delayed_task(
       runners_[0], base::TimeDelta::FromMilliseconds(10), now_src_.get());
@@ skipping 12 matching lines @@
   double ratio = static_cast<double>(linear_delayed_task.count()) /
                  static_cast<double>(quadratic_immediate_task.count());
 
   // This is by design, we want to enforce a strict ordering in task execution
   // where by delayed tasks can not skip ahead of non-delayed work.
   EXPECT_GT(ratio, 0.0);
   EXPECT_LT(ratio, 0.1);
 }
 
 TEST_F(TaskQueueManagerTest,
-       DelayedTasksDontStarveNonDelayedWork_DifferentQueue) {
+       DelayedTasksDontBadlyStarveNonDelayedWork_DifferentQueue) {
   Initialize(2u);
 
   QuadraticTask quadratic_delayed_task(
       runners_[0], base::TimeDelta::FromMilliseconds(10), now_src_.get());
   LinearTask linear_immediate_task(runners_[1], base::TimeDelta(),
                                    now_src_.get());
   base::Callback<bool()> should_exit =
       base::Bind(ShouldExit, &quadratic_delayed_task, &linear_immediate_task);
   quadratic_delayed_task.SetShouldExit(should_exit);
   linear_immediate_task.SetShouldExit(should_exit);
 
   quadratic_delayed_task.Run();
   linear_immediate_task.Run();
 
   test_task_runner_->SetAutoAdvanceNowToPendingTasks(true);
   test_task_runner_->RunUntilIdle();
 
   double ratio = static_cast<double>(linear_immediate_task.count()) /
                  static_cast<double>(quadratic_delayed_task.count());
 
-  EXPECT_GT(ratio, 0.9);
+  EXPECT_GT(ratio, 0.333);
   EXPECT_LT(ratio, 1.1);
 }
 
 TEST_F(TaskQueueManagerTest,
        ImmediateWorkCanStarveDelayedTasks_DifferentQueue) {
   Initialize(2u);
 
   QuadraticTask quadratic_immediate_task(runners_[0], base::TimeDelta(),
                                          now_src_.get());
   LinearTask linear_delayed_task(
@@ skipping 13 matching lines @@
   double ratio = static_cast<double>(linear_delayed_task.count()) /
                  static_cast<double>(quadratic_immediate_task.count());
 
   // This is by design, we want to enforce a strict ordering in task execution
   // where by delayed tasks can not skip ahead of non-delayed work.
   EXPECT_GT(ratio, 0.0);
   EXPECT_LT(ratio, 0.1);
 }
 
 }  // namespace scheduler