Provision to start base::SimpleTestTickClock at initial ticks

components/scheduler/renderer/idle_time_estimator_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 "components/scheduler/renderer/idle_time_estimator.h"
 
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/test/ordered_simple_task_runner.h"
 #include "components/scheduler/base/task_queue_manager.h"
 #include "components/scheduler/base/test_time_source.h"
@@ skipping 17 matching lines @@
 };
 
 class IdleTimeEstimatorTest : public testing::Test {
  public:
   IdleTimeEstimatorTest()
       : frame_length_(base::TimeDelta::FromMilliseconds(16)) {}
 
   ~IdleTimeEstimatorTest() 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(5000)));
     test_time_source_.reset(new TestTimeSource(clock_.get()));
     mock_task_runner_ = make_scoped_refptr(
         new cc::OrderedSimpleTaskRunner(clock_.get(), false));
     main_task_runner_ = SchedulerTqmDelegateForTest::Create(
         mock_task_runner_, make_scoped_ptr(new TestTimeSource(clock_.get())));
     manager_ = make_scoped_ptr(new TaskQueueManager(
         main_task_runner_, "test.scheduler", "test.scheduler",
         "test.scheduler.debug"));
     compositor_task_runner_ =
         manager_->NewTaskQueue(TaskQueue::Spec("compositor_tq"));
@@ skipping 107 matching lines @@
   SimulateFrameWithTwoCompositorTasks(4, 4);
   estimator_->DidCommitFrameToCompositor();
   estimator_->DidProcessTask(task);
 
   EXPECT_EQ(base::TimeDelta::FromMilliseconds(11),
             estimator_->GetExpectedIdleDuration(frame_length_));
 }
 
 
 }  // namespace scheduler