Provision to start base::SimpleTestTickClock at initial ticks

cc/scheduler/scheduler_unittest.cc

 // Copyright 2011 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 "cc/scheduler/scheduler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 193 matching lines @@
     return CallOnBeginFrame(args);
   }
 
  private:
   FakeSchedulerClient* client_;
 };
 
 class SchedulerTest : public testing::Test {
  public:
   SchedulerTest()
-      : now_src_(new base::SimpleTestTickClock()),
+      : now_src_(new base::SimpleTestTickClock(
+            base::TimeTicks() + base::TimeDelta::FromMicroseconds(1))),
         task_runner_(new OrderedSimpleTaskRunner(now_src_.get(), true)),
         fake_external_begin_frame_source_(nullptr) {
-    now_src_->Advance(base::TimeDelta::FromMicroseconds(10000));
     // A bunch of tests require NowTicks()
     // to be > BeginFrameArgs::DefaultInterval()
     now_src_->Advance(base::TimeDelta::FromMilliseconds(100));
     // Fail if we need to run 100 tasks in a row.
     task_runner_->SetRunTaskLimit(100);
   }
 
   ~SchedulerTest() override {}
 
  protected:
@@ skipping 2732 matching lines @@
   scheduler_->SetImplLatencyTakesPriority(true);
   scheduler_->SetChildrenNeedBeginFrames(true);
 
   EXPECT_SCOPED(AdvanceFrame());
   EXPECT_TRUE(client_->begin_frame_is_sent_to_children());
   EXPECT_FALSE(client_->begin_frame_args_sent_to_children().on_critical_path);
 }
 
 }  // namespace
 }  // namespace cc