Provision to start base::SimpleTestTickClock at initial ticks

components/scheduler/renderer/deadline_task_runner_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 "base/test/simple_test_tick_clock.h"
 #include "components/scheduler/renderer/deadline_task_runner.h"
 
 #include "cc/test/ordered_simple_task_runner.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace scheduler {
 
 class DeadlineTaskRunnerTest : public testing::Test {
  public:
   DeadlineTaskRunnerTest() {}
   ~DeadlineTaskRunnerTest() override {}
 
   void SetUp() override {
-    clock_.reset(new base::SimpleTestTickClock());
-    clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
+    clock_.reset(new base::SimpleTestTickClock(
+        base::TimeTicks() + base::TimeDelta::FromMicroseconds(1)));
     mock_task_runner_ = new cc::OrderedSimpleTaskRunner(clock_.get(), true);
     deadline_task_runner_.reset(new DeadlineTaskRunner(
         base::Bind(&DeadlineTaskRunnerTest::TestTask, base::Unretained(this)),
         mock_task_runner_));
     run_times_.clear();
   }
 
   bool RunUntilIdle() { return mock_task_runner_->RunUntilIdle(); }
 
   void TestTask() { run_times_.push_back(clock_->NowTicks()); }
@@ skipping 58 matching lines @@
       FROM_HERE, base::TimeDelta::FromMilliseconds(10), clock_->NowTicks());
 
   // Deleting the pending task should cancel it.
   deadline_task_runner_.reset(nullptr);
   RunUntilIdle();
 
   EXPECT_TRUE(run_times_.empty());
 };
 
 }  // namespace scheduler