Adds a flag to support "Virtual Time" to the blink scheduler

components/scheduler/child/scheduler_task_runner_delegate_impl.h

Index: components/scheduler/child/scheduler_task_runner_delegate_impl.h
diff --git a/components/scheduler/child/scheduler_task_runner_delegate_impl.h b/components/scheduler/child/scheduler_task_runner_delegate_impl.h
index 2f18b992c68728bbdd47c47a32e3bbf9c128098e..4bec96fdb96fd1b69ee81a60bc4487b9e26cd2fd 100644
--- a/components/scheduler/child/scheduler_task_runner_delegate_impl.h
+++ b/components/scheduler/child/scheduler_task_runner_delegate_impl.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_TASK_RUNNER_DELEGATE_IMPL_H_
 
 #include "base/message_loop/message_loop.h"
+#include "base/time/tick_clock.h"
 #include "components/scheduler/child/scheduler_task_runner_delegate.h"
 #include "components/scheduler/scheduler_export.h"
 
@@ -16,7 +17,8 @@ class SCHEDULER_EXPORT SchedulerTaskRunnerDelegateImpl
  public:
   // |message_loop| is not owned and must outlive the lifetime of this object.
   static scoped_refptr<SchedulerTaskRunnerDelegateImpl> Create(
-      base::MessageLoop* message_loop);
+      base::MessageLoop* message_loop,
+      scoped_ptr<base::TickClock> time_source);
 
   // SchedulerTaskRunnerDelegate implementation
   void SetDefaultTaskRunner(
@@ -30,16 +32,20 @@ class SCHEDULER_EXPORT SchedulerTaskRunnerDelegateImpl
                                   base::TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;
   bool IsNested() const override;
+  base::TimeTicks NowTicks() override;
+  void OnNoMoreWork() override;
 
  protected:
   ~SchedulerTaskRunnerDelegateImpl() override;
 
  private:
-  explicit SchedulerTaskRunnerDelegateImpl(base::MessageLoop* message_loop);
+  SchedulerTaskRunnerDelegateImpl(base::MessageLoop* message_loop,
+                                  scoped_ptr<base::TickClock> time_source);
 
   // Not owned.
   base::MessageLoop* message_loop_;
   scoped_refptr<SingleThreadTaskRunner> message_loop_task_runner_;
+  scoped_ptr<base::TickClock> time_source_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerTaskRunnerDelegateImpl);
 };