Run task queue manager work in batches

content/renderer/scheduler/task_queue_manager_unittest.cc

Index: content/renderer/scheduler/task_queue_manager_unittest.cc
diff --git a/content/renderer/scheduler/task_queue_manager_unittest.cc b/content/renderer/scheduler/task_queue_manager_unittest.cc
index a6c13478c7f6353cb1899bcd6903bab1be10fe65..34789f2754bc622908a46e96ba27fd16c0e25380 100644
--- a/content/renderer/scheduler/task_queue_manager_unittest.cc
+++ b/content/renderer/scheduler/task_queue_manager_unittest.cc
@@ -480,5 +480,36 @@ TEST_F(TaskQueueManagerTest, PostFromNestedRunloop) {
   EXPECT_THAT(run_order, ElementsAre(0, 2, 1));
 }
 
+TEST_F(TaskQueueManagerTest, WorkBatching) {
+  Initialize(1u);
+
+  manager_->SetWorkBatchSize(2);
+
+  std::vector<int> run_order;
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
+
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+  selector_->AppendQueueToService(0);
+
+  runner->PostTask(FROM_HERE, base::Bind(&TestTask, 1, &run_order));
+  runner->PostTask(FROM_HERE, base::Bind(&TestTask, 2, &run_order));
+  runner->PostTask(FROM_HERE, base::Bind(&TestTask, 3, &run_order));
+  runner->PostTask(FROM_HERE, base::Bind(&TestTask, 4, &run_order));
+
+  // Running one task in the host message loop should cause two posted tasks to
+  // get executed.
+  EXPECT_EQ(test_task_runner_->GetPendingTasks().size(), 1u);
+  test_task_runner_->RunPendingTasks();
+  EXPECT_THAT(run_order, ElementsAre(1, 2));
+
+  // The second task runs the remaining two posted tasks.
+  EXPECT_EQ(test_task_runner_->GetPendingTasks().size(), 1u);
+  test_task_runner_->RunPendingTasks();
+  EXPECT_THAT(run_order, ElementsAre(1, 2, 3, 4));
+}
+
 }  // namespace
 }  // namespace content