[cherrypick] Fix computation of runtime for throttled tasks

components/scheduler/renderer/throttled_time_domain.h

+// Copyright 2016 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_THROTTLED_TIME_DOMAIN_H_
+#define COMPONENTS_SCHEDULER_RENDERER_THROTTLED_TIME_DOMAIN_H_
+
+#include "base/macros.h"
+#include "components/scheduler/base/virtual_time_domain.h"
+
+namespace scheduler {
+
+// A time domain that's mostly a VirtualTimeDomain except that real time is used
+// when computing the delayed runtime.
+class SCHEDULER_EXPORT ThrottledTimeDomain : public VirtualTimeDomain {
+ public:
+  ThrottledTimeDomain(TimeDomain::Observer* observer,
+                      base::TickClock* tick_clock);
+  ~ThrottledTimeDomain() override;
+
+  // TimeDomain implementation:
+  base::TimeTicks ComputeDelayedRunTime(base::TimeTicks time_domain_now,
+                                        base::TimeDelta delay) const override;
+  const char* GetName() const override;
+
+ private:
+  base::TickClock* const tick_clock_;  // NOT OWNED
+
+  DISALLOW_COPY_AND_ASSIGN(ThrottledTimeDomain);
+};
+
+}  // namespace scheduler
+
+#endif  // COMPONENTS_SCHEDULER_RENDERER_THROTTLED_TIME_DOMAIN_H_