| // Copyright 2012 The Chromium Authors | 
 | // Use of this source code is governed by a BSD-style license that can be | 
 | // found in the LICENSE file. | 
 |  | 
 | #ifndef BASE_TIME_DEFAULT_TICK_CLOCK_H_ | 
 | #define BASE_TIME_DEFAULT_TICK_CLOCK_H_ | 
 |  | 
 | #include "base/base_export.h" | 
 | #include "base/time/tick_clock.h" | 
 |  | 
 | namespace base { | 
 |  | 
 | // DefaultTickClock is a TickClock implementation that uses TimeTicks::Now(). | 
 | // This is typically used by components that expose a SetTickClockForTesting(). | 
 | // Note: Overriding Time/TimeTicks altogether via | 
 | // TaskEnvironment::TimeSource::MOCK_TIME is now the preferred way of overriding | 
 | // time in unit tests. As such, there shouldn't be many new use cases for | 
 | // TickClock/DefaultTickClock anymore. | 
 | class BASE_EXPORT DefaultTickClock : public TickClock { | 
 |  public: | 
 |   ~DefaultTickClock() override; | 
 |  | 
 |   // Simply returns TimeTicks::Now(). | 
 |   TimeTicks NowTicks() const override; | 
 |  | 
 |   // Returns a shared instance of DefaultTickClock. This is thread-safe. | 
 |   static const DefaultTickClock* GetInstance(); | 
 | }; | 
 |  | 
 | }  // namespace base | 
 |  | 
 | #endif  // BASE_TIME_DEFAULT_TICK_CLOCK_H_ |