[scheduler] CPUTimeBudgetPool: Require a minimal level of budget to run

third_party/WebKit/Source/platform/scheduler/renderer/budget_pool_unittest.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/renderer/task_queue_throttler.h"
 
 #include <stddef.h>
 
 #include <memory>
 
@@ skipping 38 matching lines @@
   std::unique_ptr<base::SimpleTestTickClock> clock_;
   scoped_refptr<cc::OrderedSimpleTaskRunner> mock_task_runner_;
   scoped_refptr<SchedulerTqmDelegate> delegate_;
   std::unique_ptr<RendererSchedulerImpl> scheduler_;
   TaskQueueThrottler* task_queue_throttler_;  // NOT OWNED
 
   DISALLOW_COPY_AND_ASSIGN(BudgetPoolTest);
 };
 
 TEST_F(BudgetPoolTest, CPUTimeBudgetPool) {
-  CPUTimeBudgetPool* pool = task_queue_throttler_->CreateCPUTimeBudgetPool(
-      "test", base::nullopt, base::nullopt);
+  CPUTimeBudgetPool* pool =
+      task_queue_throttler_->CreateCPUTimeBudgetPool("test");
 
   base::TimeTicks time_zero = clock_->NowTicks();
 
   pool->SetTimeBudgetRecoveryRate(time_zero, 0.1);
 
   EXPECT_TRUE(pool->HasEnoughBudgetToRun(time_zero));
   EXPECT_EQ(time_zero, pool->GetNextAllowedRunTime());
 
   // Run an expensive task and make sure that we're throttled.
   pool->RecordTaskRunTime(time_zero,
@@ skipping 12 matching lines @@
   pool->RecordTaskRunTime(time_zero + base::TimeDelta::FromMilliseconds(2000),
                           time_zero + base::TimeDelta::FromMilliseconds(2020));
   EXPECT_TRUE(pool->HasEnoughBudgetToRun(
       time_zero + base::TimeDelta::FromMilliseconds(2020)));
   EXPECT_EQ(time_zero + base::TimeDelta::FromMilliseconds(2020),
             pool->GetNextAllowedRunTime());
 
   pool->Close();
 }
 
+TEST_F(BudgetPoolTest, CPUTimeBudgetPoolMinBudgetLevelToRun) {
+  CPUTimeBudgetPool* pool =
+      task_queue_throttler_->CreateCPUTimeBudgetPool("test");
+
+  base::TimeTicks time_zero = clock_->NowTicks();
+
+  pool->SetMinBudgetLevelToRun(time_zero,
+                               base::TimeDelta::FromMilliseconds(10));
+  pool->SetTimeBudgetRecoveryRate(time_zero, 0.1);
+
+  EXPECT_TRUE(pool->HasEnoughBudgetToRun(time_zero));
+  EXPECT_EQ(time_zero, pool->GetNextAllowedRunTime());
+
+  pool->RecordTaskRunTime(time_zero,
+                          time_zero + base::TimeDelta::FromMilliseconds(10));
+  EXPECT_FALSE(pool->HasEnoughBudgetToRun(
+      time_zero + base::TimeDelta::FromMilliseconds(15)));
+  EXPECT_FALSE(pool->HasEnoughBudgetToRun(
+      time_zero + base::TimeDelta::FromMilliseconds(150)));
+  // We need to wait extra 100ms to get budget of 10ms.
+  EXPECT_EQ(time_zero + base::TimeDelta::FromMilliseconds(200),
+            pool->GetNextAllowedRunTime());
+
+  pool->RecordTaskRunTime(time_zero + base::TimeDelta::FromMilliseconds(200),
+                          time_zero + base::TimeDelta::FromMilliseconds(205));
+  // We can run when budget is non-negative even when it less than 10ms.
+  EXPECT_EQ(time_zero + base::TimeDelta::FromMilliseconds(205),
+            pool->GetNextAllowedRunTime());
+
+  pool->RecordTaskRunTime(time_zero + base::TimeDelta::FromMilliseconds(205),
+                          time_zero + base::TimeDelta::FromMilliseconds(215));
+  EXPECT_EQ(time_zero + base::TimeDelta::FromMilliseconds(350),
+            pool->GetNextAllowedRunTime());
+}
+
 }  // namespace scheduler
 }  // namespace blink