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

components/scheduler/base/lazy_now.cc

Index: components/scheduler/base/lazy_now.cc
diff --git a/components/scheduler/base/lazy_now.cc b/components/scheduler/base/lazy_now.cc
index 411e51b56f49f1a013ba592efcfda651bba8b2e5..c80dd472440daed23fc2b274cb11fc0859398edf 100644
--- a/components/scheduler/base/lazy_now.cc
+++ b/components/scheduler/base/lazy_now.cc
@@ -4,6 +4,7 @@
 
 #include "components/scheduler/base/lazy_now.h"
 
+#include "base/time/tick_clock.h"
 #include "components/scheduler/base/task_queue_manager.h"
 
 namespace scheduler {
@@ -11,7 +12,7 @@ namespace internal {
 
 base::TimeTicks LazyNow::Now() {
   if (now_.is_null())
-    now_ = task_queue_manager_->Now();
+    now_ = tick_clock_->NowTicks();
   return now_;
 }