(reland) Adds TimeDomains to the TaskQueueManager

components/scheduler/base/delayed_task_delegate.cc

+// 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.
+
+#include "components/scheduler/base/delayed_task_delegate.h"
+
+#include <set>
+
+#include "components/scheduler/base/task_queue_impl.h"
+#include "components/scheduler/base/task_queue_manager_delegate.h"
+#include "components/scheduler/scheduler_export.h"
+
+namespace scheduler {
+
+DelayedTaskDelegate::DelayedTaskDelegate() {}
+
+DelayedTaskDelegate::~DelayedTaskDelegate() {}
+
+void DelayedTaskDelegate::ScheduleDelayedWork(
+    internal::TaskQueueImpl* queue,
+    base::TimeTicks delayed_run_time) {
+  if (!BelongsToCurrentThread()) {
+    // NOTE posting a delayed task from a different thread is not expected to be
+    // common. This pathway is less optimal than perhaps it could be because
+    // it causes two main thread tasks to be run.  Should this assumption prove
+    // to be false in future, we may need to revisit this.
+    PostScheduleDelayedWorkTaskOnMainThread(queue, delayed_run_time);
+    return;
+  }
+
+  // Make sure there's one (and only one) task posted to |delegate_|
+  // to call |DelayedDoWork| at |delayed_run_time|.
+  if (delayed_wakeup_multimap_.find(delayed_run_time) ==
+      delayed_wakeup_multimap_.end()) {
+    base::TimeDelta delay =
+        std::max(base::TimeDelta(), delayed_run_time - CachedNow());
+    ScheduleDoWork(delay);
+  }
+  delayed_wakeup_multimap_.insert(std::make_pair(delayed_run_time, queue));
+}
+
+void DelayedTaskDelegate::ScheduleDelayedWorkTask(
+    scoped_refptr<internal::TaskQueueImpl> queue,
+    base::TimeTicks delayed_run_time) {
+  InvalidateNowCache();
+  ScheduleDelayedWork(queue.get(), delayed_run_time);
+}
+
+void DelayedTaskDelegate::CancelDelayedWork(internal::TaskQueueImpl* queue) {
+  // We need to remove |task_queue| from delayed_wakeup_multimap_ which is a
+  // little awkward since it's keyed by time. O(n) running time.
+  for (DelayedWakeupMultimap::iterator iter = delayed_wakeup_multimap_.begin();
+       iter != delayed_wakeup_multimap_.end();) {
+    if (iter->second == queue) {
+      DelayedWakeupMultimap::iterator temp = iter;
+      iter++;
+      // O(1) amortized.
+      delayed_wakeup_multimap_.erase(temp);
+    } else {
+      iter++;
+    }
+  }
+}
+
+void DelayedTaskDelegate::WakeupReadyDelayedQueues() {
+  // Wake up any queues with pending delayed work.  Note std::multipmap stores
+  // the elements sorted by key, so the begin() iterator points to the earliest
+  // queue to wakeup.
+  std::set<internal::TaskQueueImpl*> dedup_set;
+  while (!delayed_wakeup_multimap_.empty()) {
+    DelayedWakeupMultimap::iterator next_wakeup =
+        delayed_wakeup_multimap_.begin();
+    if (next_wakeup->first > CachedNow())
+      break;
+    // A queue could have any number of delayed tasks pending so it's worthwhile
+    // deduping calls to MoveReadyDelayedTasksToIncomingQueue since it takes a
+    // lock.  NOTE the order in which these are called matters since the order
+    // in which EnqueueTaskLocks is called is respected when choosing which
+    // queue to execute a task from.
+    if (dedup_set.insert(next_wakeup->second).second)
+      next_wakeup->second->MoveReadyDelayedTasksToIncomingQueue();
+    delayed_wakeup_multimap_.erase(next_wakeup);
+  }
+}
+
+}  // namespace scheduler