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 <utility>
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ skipping 208 matching lines @@
 // Lets gtest print human readable Policy values.
 ::std::ostream& operator<<(::std::ostream& os,
                            const RendererScheduler::UseCase& use_case) {
   return os << RendererScheduler::UseCaseToString(use_case);
 }
 
 class RendererSchedulerImplTest : public testing::Test {
  public:
   using UseCase = RendererSchedulerImpl::UseCase;
 
-  RendererSchedulerImplTest() : clock_(new base::SimpleTestTickClock()) {
-    clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-  }
+  RendererSchedulerImplTest()
+      : clock_(new base::SimpleTestTickClock(
+            base::TimeTicks() + base::TimeDelta::FromMicroseconds(1))) {}
 
   RendererSchedulerImplTest(base::MessageLoop* message_loop)
-      : clock_(new base::SimpleTestTickClock()), message_loop_(message_loop) {
-    clock_->Advance(base::TimeDelta::FromMicroseconds(5000));
-  }
+      : clock_(new base::SimpleTestTickClock(
+            base::TimeTicks() + base::TimeDelta::FromMicroseconds(1))),
+        message_loop_(message_loop) {}
 
   ~RendererSchedulerImplTest() override {}
 
   void SetUp() override {
     if (message_loop_) {
       main_task_runner_ = SchedulerTqmDelegateImpl::Create(
           message_loop_.get(),
           make_scoped_ptr(new TestTimeSource(clock_.get())));
     } else {
       mock_task_runner_ = make_scoped_refptr(
@@ skipping 2196 matching lines @@
     }
 
     base::TimeDelta time_till_next_frame =
         EstimatedNextFrameBegin() - clock_->NowTicks();
     if (time_till_next_frame > base::TimeDelta())
       clock_->Advance(time_till_next_frame);
   }
 }
 
 }  // namespace scheduler