Scheduler/child/TimeSource could be replaced with base/time/DefaultTickClock.

components/scheduler/child/task_queue_manager.cc

Index: components/scheduler/child/task_queue_manager.cc
diff --git a/components/scheduler/child/task_queue_manager.cc b/components/scheduler/child/task_queue_manager.cc
index d9fa47c9203ff6e4da49dc4f2ffb8e9eb088bad5..569c4fa737f9d7f0647d7bb1ceed15b07333bfe8 100644
--- a/components/scheduler/child/task_queue_manager.cc
+++ b/components/scheduler/child/task_queue_manager.cc
@@ -8,11 +8,11 @@
 #include <set>
 
 #include "base/bind.h"
+#include "base/time/default_tick_clock.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "components/scheduler/child/nestable_single_thread_task_runner.h"
 #include "components/scheduler/child/task_queue_selector.h"
-#include "components/scheduler/child/time_source.h"
 
 namespace {
 const int64_t kMaxTimeTicks = std::numeric_limits<int64>::max();
@@ -467,7 +467,7 @@ TaskQueueManager::TaskQueueManager(
       task_was_run_bitmap_(0),
       pending_dowork_count_(0),
       work_batch_size_(1),
-      time_source_(new TimeSource),
+      time_source_(new base::DefaultTickClock),
       disabled_by_default_tracing_category_(
           disabled_by_default_tracing_category),
       deletion_sentinel_(new DeletionSentinel()),
@@ -724,7 +724,7 @@ void TaskQueueManager::RemoveTaskObserver(
 }
 
 void TaskQueueManager::SetTimeSourceForTesting(
-    scoped_ptr<TimeSource> time_source) {
+    scoped_ptr<base::TickClock> time_source) {
   DCHECK(main_thread_checker_.CalledOnValidThread());
   time_source_ = time_source.Pass();
 }
@@ -736,7 +736,7 @@ uint64 TaskQueueManager::GetAndClearTaskWasRunOnQueueBitmap() {
 }
 
 base::TimeTicks TaskQueueManager::Now() const {
-  return time_source_->Now();
+  return time_source_->NowTicks();
 }
 
 scoped_refptr<base::trace_event::ConvertableToTraceFormat>