(Merge m52) Fix a bug with throttling and timer queue suspension

components/scheduler/renderer/throttling_helper.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
 #define COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
 
 #include <set>
 
 #include "base/macros.h"
@@ skipping 12 matching lines @@
  public:
   ThrottlingHelper(RendererSchedulerImpl* renderer_scheduler,
                    const char* tracing_category);
 
   ~ThrottlingHelper() override;
 
   // TimeDomain::Observer implementation:
   void OnTimeDomainHasImmediateWork() override;
   void OnTimeDomainHasDelayedWork() override;
 
+  // The purpose of this method is to make sure thottling doesn't conflict with
+  // enabling/disabling the queue for policy reasons.
+  // If |task_queue| is throttled then the ThrottlingHelper remembers the
+  // |enabled| setting.  In addition if |enabled| is false then the queue is
+  // immediatly disabled.  Otherwise if |task_queue| not throttled then
+  // TaskQueue::SetEnabled(enabled) is called.
+  void SetQueueEnabled(TaskQueue* task_queue, bool enabled);
+
   // Increments the throttled refcount and causes |task_queue| to be throttled
   // if its not already throttled.
   void IncreaseThrottleRefCount(TaskQueue* task_queue);
 
   // If the refcouint is non-zero it's decremented.  If the throttled refcount
   // becomes zero then |task_queue| is unthrottled.  If the refcount was already
   // zero this function does nothing.
   void DecreaseThrottleRefCount(TaskQueue* task_queue);
 
   // Removes |task_queue| from |throttled_queues_|.
   void UnregisterTaskQueue(TaskQueue* task_queue);
 
   const ThrottledTimeDomain* time_domain() const { return time_domain_.get(); }
 
   static base::TimeTicks ThrottledRunTime(base::TimeTicks unthrottled_runtime);
 
   const scoped_refptr<TaskQueue>& task_runner() const { return task_runner_; }
 
  private:
-  using TaskQueueMap = std::map<TaskQueue*, size_t>;
+  struct Metadata {
+    Metadata() : throttling_ref_count(0), enabled(false) {}
+
+    Metadata(size_t ref_count, bool is_enabled)
+        : throttling_ref_count(ref_count), enabled(is_enabled) {}
+
+    size_t throttling_ref_count;
+    bool enabled;
+  };
+  using TaskQueueMap = std::map<TaskQueue*, Metadata>;
 
   void PumpThrottledTasks();
 
   // Note |unthrottled_runtime| might be in the past. When this happens we
   // compute the delay to the next runtime based on now rather than
   // unthrottled_runtime.
   void MaybeSchedulePumpThrottledTasksLocked(
       const tracked_objects::Location& from_here,
       base::TimeTicks now,
       base::TimeTicks unthrottled_runtime);
@@ skipping 10 matching lines @@
   base::TimeTicks pending_pump_throttled_tasks_runtime_;
 
   base::WeakPtrFactory<ThrottlingHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThrottlingHelper);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_THROTTLING_HELPER_H_