Provision to start base::SimpleTestTickClock at initial ticks

components/scheduler/renderer/webthread_impl_for_renderer_scheduler_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/webthread_impl_for_renderer_scheduler.h"
 
 #include <stddef.h>
 
 #include "base/location.h"
 #include "base/macros.h"
@@ skipping 23 matching lines @@
   MOCK_METHOD0(willProcessTask, void());
   MOCK_METHOD0(didProcessTask, void());
 };
 }  // namespace
 
 class WebThreadImplForRendererSchedulerTest : public testing::Test {
  public:
   WebThreadImplForRendererSchedulerTest() {}
 
   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)));
     scheduler_.reset(new RendererSchedulerImpl(SchedulerTqmDelegateImpl::Create(
         &message_loop_, make_scoped_ptr(new TestTimeSource(clock_.get())))));
     default_task_runner_ = scheduler_->DefaultTaskRunner();
     thread_ = scheduler_->CreateMainThread();
   }
 
   ~WebThreadImplForRendererSchedulerTest() override {}
 
   void SetWorkBatchSizeForTesting(size_t work_batch_size) {
     scheduler_->GetSchedulerHelperForTesting()->SetWorkBatchSizeForTesting(
@@ skipping 140 matching lines @@
   }
 
   message_loop_.task_runner()->PostTask(
       FROM_HERE, base::Bind(&EnterRunLoop, base::Unretained(&message_loop_),
                             base::Unretained(thread_.get())));
   message_loop_.RunUntilIdle();
   thread_->removeTaskObserver(&observer);
 }
 
 }  // namespace scheduler