Fix a build failure caused by an earlier cherry pick

third_party/WebKit/Source/core/frame/SuspendableTimer.h

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
 
 #ifndef SuspendableTimer_h
 #define SuspendableTimer_h
 
 #include "core/CoreExport.h"
 #include "core/dom/ActiveDOMObject.h"
+#include "core/dom/TaskRunnerHelper.h"
 #include "platform/Timer.h"
 
 namespace blink {
 
 class CORE_EXPORT SuspendableTimer : public TimerBase, public ActiveDOMObject {
  public:
   explicit SuspendableTimer(ExecutionContext*, TaskType);
   ~SuspendableTimer() override;
 
   // ActiveDOMObject
   void contextDestroyed() override;
   void suspend() final;
   void resume() final;
 
   void stop() override;
 
  private:
   void fired() override = 0;
 
   double m_nextFireInterval;
   double m_repeatInterval;
 #if ENABLE(ASSERT)
   bool m_suspended;
 #endif
 };
 
 }  // namespace blink
 
 #endif  // SuspendableTimer_h