Provision to start base::SimpleTestTickClock at initial ticks

components/scheduler/renderer/throttling_helper_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/throttling_helper.h"
 
 #include <stddef.h>
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ skipping 11 matching lines @@
 using testing::ElementsAre;
 
 namespace scheduler {
 
 class ThrottlingHelperTest : public testing::Test {
  public:
   ThrottlingHelperTest() {}
   ~ThrottlingHelperTest() 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)));
     mock_task_runner_ =
         make_scoped_refptr(new cc::OrderedSimpleTaskRunner(clock_.get(), true));
     delegate_ = SchedulerTqmDelegateForTest::Create(
         mock_task_runner_, make_scoped_ptr(new TestTimeSource(clock_.get())));
     scheduler_.reset(new RendererSchedulerImpl(delegate_));
     throttling_helper_ = scheduler_->throttling_helper();
     timer_queue_ = scheduler_->NewTimerTaskRunner("test_queue");
   }
 
   void TearDown() override {
@@ skipping 179 matching lines @@
   size_t task_count = 0;
   mock_task_runner_->RunTasksWhile(
       base::Bind(&MessageLoopTaskCounter, &task_count));
 
   // NOTE PumpThrottledTasks will always run at least twice because we can only
   // detect if the queues have become empty before pumping.
   EXPECT_EQ(2u, task_count);
 }
 
 }  // namespace scheduler