Provision to start base::SimpleTestTickClock at initial ticks

components/metrics/profiler/tracking_synchronizer_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/metrics/profiler/tracking_synchronizer.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/macros.h"
@@ skipping 101 matching lines @@
   using TrackingSynchronizer::SendData;
 
  private:
   ~TestTrackingSynchronizer() override {}
 };
 
 }  // namespace
 
 TEST(TrackingSynchronizerTest, ProfilerData) {
   // Testing how TrackingSynchronizer reports 2 phases of profiling.
-  auto clock = new base::SimpleTestTickClock();  // Will be owned by
-                                                 // |tracking_synchronizer|.
-  clock->Advance(base::TimeDelta::FromMilliseconds(111));
+  auto clock = new base::SimpleTestTickClock(
+      base::TimeTicks() +
+      base::TimeDelta::FromMilliseconds(
+          111));  // Will be owned by |tracking_synchronizer|.
 
   scoped_refptr<TestTrackingSynchronizer> tracking_synchronizer =
       new TestTrackingSynchronizer(make_scoped_ptr(clock));
 
   clock->Advance(base::TimeDelta::FromMilliseconds(222));
 
   tracking_synchronizer->RegisterPhaseCompletion(
       ProfilerEventProto::EVENT_FIRST_NONEMPTY_PAINT);
 
   tracked_objects::ProcessDataSnapshot profiler_data;
   ProcessDataPhaseSnapshot snapshot0;
   tracked_objects::TaskSnapshot task_snapshot0;
   task_snapshot0.death_thread_name = "death_thread0";
   snapshot0.tasks.push_back(task_snapshot0);
   ProcessDataPhaseSnapshot snapshot1;
   profiler_data.phased_snapshots[0] = snapshot0;
   tracked_objects::TaskSnapshot task_snapshot1;
   task_snapshot1.death_thread_name = "death_thread1";
   snapshot1.tasks.push_back(task_snapshot1);
   profiler_data.phased_snapshots[1] = snapshot1;
   profiler_data.process_id = 239;
 
   clock->Advance(base::TimeDelta::FromMilliseconds(444));
   TestObserver test_observer;
   tracking_synchronizer->SendData(
       profiler_data, ProfilerEventProto::TrackedObject::PLUGIN, &test_observer);
 }
 
 }  // namespace metrics