Move throttling of background timers into the renderer scheduler

components/scheduler/base/time_domain.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_BASE_TIME_DOMAIN_H_
 #define COMPONENTS_SCHEDULER_BASE_TIME_DOMAIN_H_
 
 #include <map>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "components/scheduler/base/lazy_now.h"
 #include "components/scheduler/base/task_queue_impl.h"
 #include "components/scheduler/scheduler_export.h"
 
 namespace scheduler {
 namespace internal {
 class TaskQueueImpl;
 }  // internal
 class TaskQueueManager;
 class TaskQueueManagerDelegate;
 
 class SCHEDULER_EXPORT TimeDomain : public base::RefCounted<TimeDomain> {
  public:
-  TimeDomain();
+  class SCHEDULER_EXPORT Observer {
+   public:
+    virtual ~Observer() {}
+
+    // Called when RegisterAsUpdatableTaskQueue is called. Can fire from any

[Sami, 2015/11/25 17:12:25]

nit: these two comments don't really make sense unless you know how TimeDomain
works internally. Maybe just describe them more generally?

[alex clarke (OOO till 29th), 2015/11/26 18:43:27]

Done.

+    // thread.
+    virtual void OnTimeDomainHasImmediateWork() = 0;
+
+    // Called when RequestWakeup is called. Called only from the main thread.
+    virtual void OnTimeDomainHasDelayedWork() = 0;
+  };
+
+  explicit TimeDomain(Observer* observer);
 
   // Returns a LazyNow that evaluate this TimeDomain's Now.  Can be called from
   // any thread.
   // TODO(alexclarke): Make this main thread only.
   virtual LazyNow CreateLazyNow() = 0;
 
   // Some TimeDomains support virtual time, this method tells us to advance time
   // if possible and return true if time was advanced.
   virtual bool MaybeAdvanceTime() = 0;
 
@@ skipping 69 matching lines @@
 
   // This lock guards only |newly_updatable_|.  It's not expected to be heavily
   // contended.
   base::Lock newly_updatable_lock_;
   std::vector<internal::TaskQueueImpl*> newly_updatable_;
 
   // Set of task queues with avaliable work on the incoming queue.  This should
   // only be accessed from the main thread.
   std::set<internal::TaskQueueImpl*> updatable_queue_set_;
 
+  Observer* observer_;
+
   base::ThreadChecker main_thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeDomain);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_BASE_TIME_DOMAIN_H_