Provision to start base::SimpleTestTickClock at initial ticks

components/scheduler/renderer/renderer_scheduler_impl_unittest.cc

 // Copyright 2014 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/renderer_scheduler_impl.h"
 
 #include "base/callback.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/test/ordered_simple_task_runner.h"
@@ skipping 166 matching lines @@
 // Lets gtest print human readable Policy values.
 ::std::ostream& operator<<(::std::ostream& os,
                            const RendererSchedulerImplForTest::Policy& policy) {
   return os << RendererSchedulerImplForTest::PolicyToString(policy);
 }
 
 class RendererSchedulerImplTest : public testing::Test {
  public:
   using Policy = RendererSchedulerImpl::Policy;
 
-  RendererSchedulerImplTest() : clock_(new base::SimpleTestTickClock()) {
-    clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-  }
+  RendererSchedulerImplTest() : clock_(new base::SimpleTestTickClock()) {}
 
   RendererSchedulerImplTest(base::MessageLoop* message_loop)
-      : clock_(new base::SimpleTestTickClock()), message_loop_(message_loop) {
-    clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-  }
+      : clock_(new base::SimpleTestTickClock()), message_loop_(message_loop) {}
 
   ~RendererSchedulerImplTest() override {}
 
   void SetUp() override {
     if (message_loop_) {
       nestable_task_runner_ =
           SchedulerMessageLoopDelegate::Create(message_loop_.get());
     } else {
       mock_task_runner_ = make_scoped_refptr(
           new cc::OrderedSimpleTaskRunner(clock_.get(), false));
@@ skipping 1584 matching lines @@
 
 TEST_F(RendererSchedulerImplTest, ShutdownPreventsPostingOfNewTasks) {
   scheduler_->Shutdown();
   std::vector<std::string> run_order;
   PostTestTasks(&run_order, "D1 C1");
   RunUntilIdle();
   EXPECT_TRUE(run_order.empty());
 }
 
 }  // namespace scheduler