[scheduler] Implement time-based cpu throttling.

third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc b/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
index 1b0980a4f4e00ccf236f4bc2250683d0b744c3b7..2bd7aba0233369105e11c91b5d124aca6b8eb035 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
@@ -533,6 +533,20 @@ bool TaskQueueImpl::HasPendingImmediateWork() const {
   return !any_thread().immediate_incoming_queue.empty();
 }
 
+bool TaskQueueImpl::NextScheduledWakeUp(base::TimeTicks* wakeup) {
+  LazyNow lazy_now = main_thread_only().time_domain->CreateLazyNow();
+  MoveReadyDelayedTasksToDelayedWorkQueue(&lazy_now);
+
+  if (main_thread_only().delayed_incoming_queue.empty())
+    return false;
+
+  if (wakeup) {

[alex clarke (OOO till 29th), 2016/09/07 15:13:07]

I don't think we should allow |wakeup| to be null.  BTW
main_thread_only().delayed_incoming_queue.begin() is O(1).

[altimin, 2016/09/09 15:43:57]

Done.

+    *wakeup =
+        main_thread_only().delayed_incoming_queue.begin()->delayed_run_time;
+  }
+  return true;
+}
+
 void TaskQueueImpl::MoveReadyDelayedTasksToDelayedWorkQueue(LazyNow* lazy_now) {
   // Enqueue all delayed tasks that should be running now.
   while (!main_thread_only().delayed_incoming_queue.empty()) {