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..f7929ddc19e8176b0328be4f9bbb82e39f96ff0a 100644
--- a/content/renderer/scheduler/renderer_scheduler_impl.h
+++ b/content/renderer/scheduler/renderer_scheduler_impl.h
@@ -53,6 +53,7 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
 
  private:
   friend class RendererSchedulerImplTest;
+  friend class MockRendererSchedulerImpl;
 
   // Keep RendererSchedulerImpl::TaskQueueIdToString in sync with this enum.
   enum QueueId {
@@ -118,14 +119,18 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
   Policy SchedulerPolicy() const;
 
   // Posts a call to UpdatePolicy on the control runner to be run after |delay|
-  void PostUpdatePolicyOnControlRunner(base::TimeDelta delay);
+  // Ensures that there can only be one pending delayed and one non-delayed
+  // UpdatePolicy task.
+  void PostUpdatePolicyOnControlRunnerLocked(base::TimeDelta delay);

[Sami, 2015/03/10 16:19:38]

Should we call this MaybePost... to match the other functions that do similar
things?

 
   // 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.
-  void UpdatePolicy();
+  // Updates the scheduler policy. Must be called from the main thread. If
+  // |clear_pending_non_delayed_update_policy| is true then
+  // pending_non_delayed_update_policy_ will be set to false.
+  virtual void UpdatePolicy(bool clear_pending_non_delayed_update_policy);
 
   // 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
@@ -159,6 +164,8 @@ class CONTENT_EXPORT RendererSchedulerImpl : public RendererScheduler {
 
   base::Closure update_policy_closure_;
   CancelableClosureHolder end_idle_period_closure_;
+  CancelableClosureHolder delayed_update_policy_closure_;
+  bool pending_non_delayed_update_policy_;
 
   // Don't access current_policy_ directly, instead use SchedulerPolicy().
   Policy current_policy_;