Prevent multiple pending UpdatePolicy tasks.

content/renderer/scheduler/renderer_scheduler_impl.h

Index: content/renderer/scheduler/renderer_scheduler_impl.h
diff --git a/content/renderer/scheduler/renderer_scheduler_impl.h b/content/renderer/scheduler/renderer_scheduler_impl.h
index c908a974a0d8f21cf24f8cb34d36fc053a1d68c8..167b79691e4ac46a01a7ec85832b0ec88199877b 100644
--- a/content/renderer/scheduler/renderer_scheduler_impl.h
+++ b/content/renderer/scheduler/renderer_scheduler_impl.h
@@ -10,6 +10,7 @@
 #include "base/threading/thread_checker.h"
 #include "cc/test/test_now_source.h"
 #include "content/renderer/scheduler/cancelable_closure_holder.h"
+#include "content/renderer/scheduler/deadline_task_runner.h"
 #include "content/renderer/scheduler/renderer_scheduler.h"
 #include "content/renderer/scheduler/single_thread_idle_task_runner.h"
 #include "content/renderer/scheduler/task_queue_manager.h"
@@ -53,6 +54,7 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
 
  private:
   friend class RendererSchedulerImplTest;
+  friend class MockRendererSchedulerImpl;
 
   // Keep RendererSchedulerImpl::TaskQueueIdToString in sync with this enum.
   enum QueueId {
@@ -117,21 +119,27 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
   // Returns the current scheduler policy. Must be called from the main thread.
   Policy SchedulerPolicy() const;
 
-  // Posts a call to UpdatePolicy on the control runner to be run after |delay|
-  void PostUpdatePolicyOnControlRunner(base::TimeDelta delay);
+  // Schedules an immediate PolicyUpdate, if there isn't one already pending and
+  // sets |policy_may_need_update_|. Note |incoming_signals_lock_| must be
+  // locked.
+  void EnsureUgentPolicyUpdatePostedOnMainThread(

[Sami, 2015/03/12 18:15:22]

s/Ugent/Urgent/

[alex clarke (OOO till 29th), 2015/03/12 18:24:08]

Done.

+      const tracked_objects::Location& from_here);
 
   // Update the policy if a new signal has arrived. Must be called from the main
   // thread.
   void MaybeUpdatePolicy();
 
-  // Updates the scheduler policy. Must be called from the main thread.
+  // Locks |incoming_signals_lock_| and updates the scheduler policy.
+  // Must be called from the main thread.
   void UpdatePolicy();
+  virtual void UpdatePolicyLocked();
 
   // Helper for computing the new policy. |new_policy_duration| will be filled
   // with the amount of time after which the policy should be updated again. If
   // the duration is zero, a new policy update will not be scheduled. Must be
   // called with |incoming_signals_lock_| held.
-  Policy ComputeNewPolicy(base::TimeDelta* new_policy_duration);
+  Policy ComputeNewPolicy(base::TimeDelta* new_policy_duration,

[Sami, 2015/03/12 18:15:22]

nit: I'd swap the arguments so that the out argument is last.

[alex clarke (OOO till 29th), 2015/03/12 18:24:08]

Good point, that's actually in the style guide.

+                          base::TimeTicks now);
 
   // An input event of some sort happened, the policy may need updating.
   void UpdateForInputEvent(blink::WebInputEvent::Type type);
@@ -158,6 +166,7 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
   scoped_refptr<SingleThreadIdleTaskRunner> idle_task_runner_;
 
   base::Closure update_policy_closure_;
+  DeadlineTaskRunner delayed_update_policy_runner_;
   CancelableClosureHolder end_idle_period_closure_;
 
   // Don't access current_policy_ directly, instead use SchedulerPolicy().