Worker: Introduce per-global-scope task scheduler

third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc
index a93dca0474ba97202e2b12c32a923b9577e2c5fa..db853d0ccf13728633b81f60998f75e00b8cd4ec 100644
--- a/third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/child/worker_scheduler_impl.cc
@@ -8,6 +8,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
+#include "platform/Histogram.h"
 #include "platform/scheduler/base/time_converter.h"
 #include "platform/scheduler/child/scheduler_tqm_delegate.h"
 #include "public/platform/scheduler/base/task_queue.h"
@@ -120,6 +121,16 @@ void WorkerSchedulerImpl::Shutdown() {
   helper_.Shutdown();
 }
 
+scoped_refptr<TaskQueue> WorkerSchedulerImpl::NewUnthrottledTaskRunner(
+    TaskQueue::QueueType queue_type) {
+  helper_.CheckOnValidThread();
+  scoped_refptr<TaskQueue> unthrottled_task_queue(
+      helper_.NewTaskQueue(TaskQueue::Spec(queue_type)
+                               .SetShouldMonitorQuiescence(true)
+                               .SetTimeDomain(nullptr)));
+  return unthrottled_task_queue;
+}
+
 SchedulerHelper* WorkerSchedulerImpl::GetSchedulerHelperForTesting() {
   return &helper_;
 }
@@ -139,6 +150,12 @@ void WorkerSchedulerImpl::WillProcessTask(TaskQueue* task_queue,
 void WorkerSchedulerImpl::DidProcessTask(TaskQueue* task_queue,
                                          double start_time,
                                          double end_time) {
+  DEFINE_THREAD_SAFE_STATIC_LOCAL(
+      CustomCountHistogram, task_time_counter,
+      new CustomCountHistogram("WorkerThread.Task.Time", 0, 10000000, 50));
+  task_time_counter.Count((end_time - start_time) *
+                          base::Time::kMicrosecondsPerSecond);
+
   base::TimeTicks start_time_ticks =
       MonotonicTimeInSecondsToTimeTicks(start_time);
   base::TimeTicks end_time_ticks = MonotonicTimeInSecondsToTimeTicks(end_time);