Prepare for per-webview virtual time

components/scheduler/renderer/auto_advancing_virtual_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_AUTO_ADVANCING_VIRTUAL_TIME_DOMAIN_H_
+#define COMPONENTS_SCHEDULER_RENDERER_AUTO_ADVANCING_VIRTUAL_TIME_DOMAIN_H_
+
+#include "base/macros.h"
+#include "components/scheduler/base/virtual_time_domain.h"
+
+namespace scheduler {
+
+// A time domain that runs tasks sequentially in time order but doesn't sleep
+// between delayed tasks.
+//
+// KEY: A-E are delayed tasks
+// |    A   B C  D           E  (Execution with RealTimeDomain)
+// |-----------------------------> time
+//
+// |ABCDE                       (Execution with AutoAdvancingVirtualTimeDomain)
+// |-----------------------------> time
+class SCHEDULER_EXPORT AutoAdvancingVirtualTimeDomain
+    : public VirtualTimeDomain {
+ public:
+  explicit AutoAdvancingVirtualTimeDomain(base::TimeTicks initial_time);
+  ~AutoAdvancingVirtualTimeDomain() override;
+
+  // TimeDomain implementation:
+  bool MaybeAdvanceTime() override;
+  void RequestWakeup(base::TimeTicks now, base::TimeDelta delay) override;
+  const char* GetName() const override;
+
+  // Controls whether or not virtual time is allowed to advance, when the
+  // TaskQueueManager runs out of immediate work to do.
+  void SetCanAdvanceVirtualTime(bool can_advance_virtual_time);
+
+ private:
+  bool can_advance_virtual_time_;
+
+  DISALLOW_COPY_AND_ASSIGN(AutoAdvancingVirtualTimeDomain);
+};
+
+}  // namespace scheduler
+
+#endif  // COMPONENTS_SCHEDULER_RENDERER_AUTO_ADVANCING_VIRTUAL_TIME_DOMAIN_H_