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

components/scheduler/child/scheduler_task_runner_delegate_impl.cc

Index: components/scheduler/child/scheduler_task_runner_delegate_impl.cc
diff --git a/components/scheduler/child/scheduler_task_runner_delegate_impl.cc b/components/scheduler/child/scheduler_task_runner_delegate_impl.cc
index 0c34554b10675f665d04bd6235704d73624915ff..1046dab4ea70d68c6bcfef4cde115eb59d09b9c9 100644
--- a/components/scheduler/child/scheduler_task_runner_delegate_impl.cc
+++ b/components/scheduler/child/scheduler_task_runner_delegate_impl.cc
@@ -8,14 +8,19 @@ namespace scheduler {
 
 // static
 scoped_refptr<SchedulerTaskRunnerDelegateImpl>
-SchedulerTaskRunnerDelegateImpl::Create(base::MessageLoop* message_loop) {
-  return make_scoped_refptr(new SchedulerTaskRunnerDelegateImpl(message_loop));
+SchedulerTaskRunnerDelegateImpl::Create(
+    base::MessageLoop* message_loop,
+    scoped_ptr<base::TickClock> time_source) {
+  return make_scoped_refptr(
+      new SchedulerTaskRunnerDelegateImpl(message_loop, time_source.Pass()));
 }
 
 SchedulerTaskRunnerDelegateImpl::SchedulerTaskRunnerDelegateImpl(
-    base::MessageLoop* message_loop)
+    base::MessageLoop* message_loop,
+    scoped_ptr<base::TickClock> time_source)
     : message_loop_(message_loop),
-      message_loop_task_runner_(message_loop->task_runner()) {}
+      message_loop_task_runner_(message_loop->task_runner()),
+      time_source_(time_source.Pass()) {}
 
 SchedulerTaskRunnerDelegateImpl::~SchedulerTaskRunnerDelegateImpl() {
   RestoreDefaultTaskRunner();
@@ -54,4 +59,10 @@ bool SchedulerTaskRunnerDelegateImpl::IsNested() const {
   return message_loop_->IsNested();
 }
 
+base::TimeTicks SchedulerTaskRunnerDelegateImpl::NowTicks() {
+  return time_source_->NowTicks();
+}
+
+void SchedulerTaskRunnerDelegateImpl::OnNoMoreWork() {}
+
 }  // namespace scheduler