Add testRunner.runIdleTasks() to force idle tasks to run.

components/scheduler/renderer/renderer_scheduler_impl.h

Index: components/scheduler/renderer/renderer_scheduler_impl.h
diff --git a/components/scheduler/renderer/renderer_scheduler_impl.h b/components/scheduler/renderer/renderer_scheduler_impl.h
index 8805cb6d13b73fb3ccea164cfde85d699b738327..165c85e14d92e104024c1ea6575da8186f2b9899 100644
--- a/components/scheduler/renderer/renderer_scheduler_impl.h
+++ b/components/scheduler/renderer/renderer_scheduler_impl.h
@@ -106,6 +106,7 @@ class SCHEDULER_EXPORT RendererSchedulerImpl
   TaskCostEstimator* GetTimerTaskCostEstimatorForTesting();
   IdleTimeEstimator* GetIdleTimeEstimatorForTesting();
   base::TimeTicks CurrentIdleTaskDeadlineForTesting() const;
+  void RunIdleTasksForTesting(const base::Closure&);

[Sami, 2016/04/06 15:52:37]

nit: Please name the parameter (Chromium style doesn't strictly require it but
the code here has names for everything).

[szager1, 2016/04/06 17:55:30]

Done.

 
   base::TickClock* tick_clock() const;
 
@@ -184,6 +185,9 @@ class SCHEDULER_EXPORT RendererSchedulerImpl
   void OnIdlePeriodEnded() override;
 
   void EndIdlePeriod();
+  void EndIdlePeriodForTesting(
+      const base::Closure& callback,
+      base::TimeTicks time_remaining);

[Sami, 2016/04/06 15:52:37]

Did you mean to remove this parameter?

Also, the callback doesn't seem that useful since it is just synchronously
executed.

[szager1, 2016/04/06 17:55:30]

Because this is posted as an idle task, it has to match the IdleTask interface,
which takes a TimeTicks argument.

The callback is useful because it runs *after* the call to EndIdlePeriod().  In
some cases, I'd like to be able to write test code that does not run during idle
time:

requestIdleCallback(testFunction1);
testRunner.runIdleTasks(() => {
  // Guaranteed not to be in idle time.
  requestIdleCallback(testFunction2);
  requestAnimationFrame(() => {
    // Guaranteed that testFunction2 has not yet run.
  });
});

[Sami, 2016/04/06 18:01:58]

Ah sorry, I wasn't paying attention while reading this. Somehow I thought this
was part of the public interface.

 
   // Returns the serialized scheduler state for tracing.
   scoped_ptr<base::trace_event::ConvertableToTraceFormat> AsValue(
@@ -343,6 +347,7 @@ class SCHEDULER_EXPORT RendererSchedulerImpl
     bool has_visible_render_widget_with_touch_handler;
     bool begin_frame_not_expected_soon;
     bool expensive_task_blocking_allowed;
+    bool in_idle_period_for_testing;
     std::set<WebViewSchedulerImpl*> web_view_schedulers_;  // Not owned.
   };