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

components/scheduler/base/lazy_now.h

 // Copyright 2015 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.
 
 #ifndef COMPONENTS_SCHEDULER_BASE_LAZY_NOW_H_
 #define COMPONENTS_SCHEDULER_BASE_LAZY_NOW_H_
 
 #include "base/time/time.h"
 
+namespace base {
+class TickClock;
+}
+
 namespace scheduler {
-class TaskQueueManager;
-
 namespace internal {
 
 // Now() is somewhat expensive so it makes sense not to call Now() unless we
 // really need to.
 class LazyNow {
  public:
-  explicit LazyNow(base::TimeTicks now)
-      : task_queue_manager_(nullptr), now_(now) {
+  explicit LazyNow(base::TimeTicks now) : tick_clock_(nullptr), now_(now) {
     DCHECK(!now.is_null());
   }
 
-  explicit LazyNow(TaskQueueManager* task_queue_manager)
-      : task_queue_manager_(task_queue_manager) {}
+  explicit LazyNow(base::TickClock* tick_clock) : tick_clock_(tick_clock) {}
 
   base::TimeTicks Now();
 
  private:
-  TaskQueueManager* task_queue_manager_;  // NOT OWNED
+  base::TickClock* tick_clock_;  // NOT OWNED
   base::TimeTicks now_;
 };
 
 }  // namespace internal
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_BASE_LAZY_NOW_H_