Report expected task queueing time via UMA

components/scheduler/renderer/renderer_scheduler_impl.cc

Index: components/scheduler/renderer/renderer_scheduler_impl.cc
diff --git a/components/scheduler/renderer/renderer_scheduler_impl.cc b/components/scheduler/renderer/renderer_scheduler_impl.cc
index 9936a69f9fa5b9489f626e9bc478d8b8048f80a0..c58fd1fa77bb6a3d6526585097bef2c463e15ba7 100644
--- a/components/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/components/scheduler/renderer/renderer_scheduler_impl.cc
@@ -8,6 +8,8 @@
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/output/begin_frame_args.h"
@@ -56,8 +58,10 @@ RendererSchedulerImpl::RendererSchedulerImpl(
           base::Bind(&RendererSchedulerImpl::UpdatePolicy,
                      base::Unretained(this)),
           helper_.ControlTaskRunner()),
-      main_thread_only_(compositor_task_runner_,
+      main_thread_only_(this,
+                        compositor_task_runner_,
                         helper_.scheduler_tqm_delegate().get()),
+      coarse_duration_timer_observing_(false),
       policy_may_need_update_(&any_thread_lock_),
       weak_factory_(this) {
   throttling_helper_.reset(new ThrottlingHelper(this, "renderer.scheduler"));
@@ -78,6 +82,7 @@ RendererSchedulerImpl::RendererSchedulerImpl(
       this);
 
   helper_.SetObserver(this);
+  AddTaskObserver(&MainThreadOnly().queueing_time_estimator);
 }
 
 RendererSchedulerImpl::~RendererSchedulerImpl() {
@@ -93,6 +98,7 @@ RendererSchedulerImpl::~RendererSchedulerImpl() {
     timer_queue->RemoveTaskObserver(
         &MainThreadOnly().timer_task_cost_estimator);
   }
+  RemoveTaskObserver(&MainThreadOnly().queueing_time_estimator);
 
   // Ensure the renderer scheduler was shut down explicitly, because otherwise
   // we could end up having stale pointers to the Blink heap which has been
@@ -101,6 +107,7 @@ RendererSchedulerImpl::~RendererSchedulerImpl() {
 }
 
 RendererSchedulerImpl::MainThreadOnly::MainThreadOnly(
+    RendererSchedulerImpl* renderer_scheduler_impl,
     const scoped_refptr<TaskQueue>& compositor_task_runner,
     base::TickClock* time_source)
     : loading_task_cost_estimator(time_source,
@@ -113,6 +120,9 @@ RendererSchedulerImpl::MainThreadOnly::MainThreadOnly(
                           time_source,
                           kShortIdlePeriodDurationSampleCount,
                           kShortIdlePeriodDurationPercentile),
+      queueing_time_estimator(renderer_scheduler_impl,
+                              renderer_scheduler_impl->coarse_duration_timer(),
+                              base::TimeDelta::FromSeconds(5)),
       current_use_case(UseCase::NONE),
       timer_queue_suspend_count(0),
       navigation_task_expected_count(0),
@@ -444,6 +454,14 @@ bool RendererSchedulerImpl::ShouldPrioritizeInputEvent(
 void RendererSchedulerImpl::DidHandleInputEventOnCompositorThread(
     const blink::WebInputEvent& web_input_event,
     InputEventState event_state) {
+
+  // TODO - move this.
+  if (coarse_duration_timer_observing_ == false) {
+    coarse_duration_timer_observing_ = true;
+    base::MessageLoop::current()->AddRecentTimeObserver(
+        &coarse_duration_timer_);
+  }

[tdresser, 2016/05/30 19:07:46]

^

+
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
                "RendererSchedulerImpl::DidHandleInputEventOnCompositorThread");
   if (!ShouldPrioritizeInputEvent(web_input_event))
@@ -1330,4 +1348,14 @@ void RendererSchedulerImpl::OnTriedToExecuteBlockedTask(
   }
 }
 
+void RendererSchedulerImpl::OnQueueingTimeForWindowEstimated(
+    base::TimeDelta queueing_time) {
+  // TODO - UMA_HISTOGRAM_TIMES is probably wrong.
+  UMA_HISTOGRAM_TIMES("RendererScheduler.ExpectedTaskQueueingDuration",
+                      queueing_time);
+  TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
+                 "estimated_queueing_time_for_window",
+                 queueing_time.InMillisecondsF());
+}
+
 }  // namespace scheduler